US3690756A - Color xerography - Google Patents

Color xerography Download PDF

Info

Publication number
US3690756A
US3690756A US126742A US3690756DA US3690756A US 3690756 A US3690756 A US 3690756A US 126742 A US126742 A US 126742A US 3690756D A US3690756D A US 3690756DA US 3690756 A US3690756 A US 3690756A
Authority
US
United States
Prior art keywords
image
light
photoconductive
color
copy
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US126742A
Other languages
English (en)
Inventor
William A Smith
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Northrop Grumman Systems Corp
Xerox Corp
Original Assignee
Xerox Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Application granted granted Critical
Publication of US3690756A publication Critical patent/US3690756A/en
Assigned to NORTHROP CORPORATION, A DEL. CORP. reassignment NORTHROP CORPORATION, A DEL. CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: NORTHROP CORPORATION, A CA. CORP.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0105—Details of unit
    • G03G15/011—Details of unit for exposing
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0142—Structure of complete machines
    • G03G15/0178—Structure of complete machines using more than one reusable electrographic recording member, e.g. one for every monocolour image
    • G03G15/0194—Structure of complete machines using more than one reusable electrographic recording member, e.g. one for every monocolour image primary transfer to the final recording medium
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/01—Apparatus for electrographic processes using a charge pattern for producing multicoloured copies
    • G03G15/0142—Structure of complete machines
    • G03G15/0147—Structure of complete machines using a single reusable electrographic recording member
    • G03G15/0152—Structure of complete machines using a single reusable electrographic recording member onto which the monocolour toner images are superposed before common transfer from the recording member
    • G03G15/0163—Structure of complete machines using a single reusable electrographic recording member onto which the monocolour toner images are superposed before common transfer from the recording member primary transfer to the final recording medium
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
    • G03G2215/0103—Plural electrographic recording members
    • G03G2215/0119—Linear arrangement adjacent plural transfer points
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/01—Apparatus for electrophotographic processes for producing multicoloured copies
    • G03G2215/0151—Apparatus for electrophotographic processes for producing multicoloured copies characterised by the technical problem
    • G03G2215/0158—Colour registration

Definitions

  • beam splitting means for separating the light image into at least a first and second light beam, which are conducted along different optical paths of equal lengths through separate filters of dissimilar colors;
  • PATENTEIISEP I2 I972 SHEEI 2 BF 3 DRUM '3 (5h: Q 53fi LIGHT SPLITTER I SECTION ORIGINAL LIGHT SPLITTER "I SECTION B STEPS Tic, 3
  • This invention relates to polychromatic electrostatographic imaging and, more particularly, a xerographic system wherein an original is light scanned, .and the resultant light beam is separated into at least two parts which are sent through separate filters and used to simultaneously discharge in imagewise configuration separate charged photoconductive areas.
  • the imagewise discharged photoconductive areas are developed with toner compositions of different colors and the developed images are successively transferred in registered configuration onto a copy material which may be a stack of separate sheets or a continuous copyweb.
  • separate photoconductive surfaces are placed at the terminus of each optical path.
  • the size and location of the photoconductive surfaces are such that the copy material traveling from one surface to another, receives superimposed toner images of different color thereby producing a color reproduction of the original.
  • each surface can be driven by the same drive means at the same lineal speed, the copy material can likewise move at one and the same speed, and critical timing problems, which would arise if three photoconductor surfaces of the same circumference were used, are obviated.
  • the electrostatographic system of this invention may suitably include three photoconductive areas, each being discharged in imagewise configuration representative of a single color component of the original, and developed with toner of a primary color, whereby when all three developed images are superimposed on the copy material, a full color reproduction of the original is created.
  • the formation and development of latent electrostatic images on an electrostatographic imaging surface is well known.
  • the basic electrostatographic process as taught by C. F. Carlson in U.S. Pat. No. 2,297,691, involves placing a uniform electrostatic charge on a photoconductive insulating layer, exposing the layer to a light and shadow image to dissipate the charge on the areas of the layer exposed to the light and developing the resulting latent electrostatic image by depositing on the image a finely-divided electroscopic material referred to in the art as toner.
  • the toner will normally be attracted to those areas of the layer which retain a charge, thereby forming a toner image corresponding to the latent electrostatic image.
  • This powder image may then be transferred to a support surface such as paper.
  • the transferred image may subsequently be permanently affixed to the support surface as by heat.
  • the powder image may be fixed to the photoconductive layer if elimination of the powder image transfer step is desired.
  • Other suitable fixing means such as solvent or overcoating treatment may be substituted for the foregoing heat fixing step.
  • the electrostatographic preparation of a color copy employs the same principles used in lithography for substractive color printing. This involves formation of three .or more light images, each image representing the proportionate amount of a colored toner to be used in developing the exposed photoconductive surface. To do this, requires separation of the colors of the original. Color separation is effected through the absorption and transmission characteristics of the transparent ink films printed on a white paper original. The yellow ink in the original reflects almost as much red and green as the paper, but almost completely absorbs blue. Thus, yellow controls where blue reflects from the white paper. A blue filter transmitting only its third of the spectrum is the correct filter to use to provide correct filter separation tone values for a yellow toner. The desired effect is to record only where the blue light comes from the original. When a positive is made from this negative, it will be a record of the minus-blue (yellow) of the copy.
  • magenta ink on the original absorbs green light without disturbing the reflectance of the red and blue light by the paper.
  • a green filter which transmits its own third of the spectrum will be the proper filter to record the red areas of the original.
  • magenta toner When a positive is made from this negative with magenta toner, it will record the minus-green (red) areas of the original.
  • the blue ink (cyan) in the original absorbs red light without disturbing the reflectance of the green and blue light.
  • a red filter which transmits its own third of the spectrum is used to control the red light reflected by the copy.
  • Developing the resultant negative with cyan ink will give a positive which is a record of the blue areas in the original.
  • an object of this invention is to provide an electrostatographic apparatus which has the capacity to conveniently produce color images using one or more photoconductive areas to transfer different color images of a color original to a copy material.
  • FIG. 1 is a schematic representation of one copying system of this invention employing three separate photoconductive surfaces imaged simultaneously by a single light scanning of an original document.
  • FIG. 2 is a graphic illustration of the travel of two points on the copy material relative to three imaged photoconductive surfaces, moving at the same lineal speed.
  • FIG. 3 is a graphic illustration of the image inversions and reversals at the several mirrors and light splitters in the light path, showing that by the system given in FIG. 1, the three images arrive in phase with respect to both each other and the original.
  • FIG. 4 is a schematic representation of another embodiment of this invention in which a single photoconductive surface is simultaneously imaged in three separate areas with color separation images of the original copy.
  • an optical system which uses the light image produced by a single scanning of a color original to simultaneously form color separation images on three different photoconductive areas.
  • the light image formed by scanning the original copy is passed through a focusing lens assembly separated by beam splitters into at least three light beams which are color filtered and conducted along optical paths of equal lengths to expose separate photoconductive areas and thereby record the respective color separation images.
  • An essential part of the present invention is that a single light scanning of the original copy can be employed to simultaneously produce three or more color separation images on three or more separate photoconductive areas, thus overcoming the difficulties inherent in known reproduction systems which required a separate light scanning step for each color separation image.
  • the choice of specific beam splitting devices, color filters or photoconductors is not a critical part of the present invention.
  • monochromatic beam splitters can be used to concurrently separate the light beam into parts and produce one color separation image or the beam splitting and color filtration functions can be performed by separate beam splitting and filter devices.
  • conventional commercial subtractive printing processes which divide the color spectrum into thirds and produces three color separation images can be used herein, but other modifications involving a lesser or greater number of color separations are also useful.
  • the color separation images can be used to image separate areas on one photoconductive surface or three separate photoconductive surfaces.
  • FIG. 1 is depicted an imaging system of the invention in which an optical system with two light splitters and three color filters is used to form three color separation images on three separate photoconductive surfaces.
  • a color original depicted by reference numeral 1 is moved, in the direction shown, past exposure lamps 2 producing a light beam image which passes through slit 3 along path 4 through focusing lens 5 and along path 6 to light splitter No. 1 shown generally by reference numeral 7.
  • the beam is split into 2 parts shown generally by reference numerals 9 and 10.
  • the part of the light beam conducted along path 10 proceeds to light splitter No. 2 shown generally by reference numeral 11.
  • the beam is separated and conducted along paths 13 and 14 respectively.
  • the beam conducted along path 13 impinges upon mirror No. 4 shown by reference numeral 15.
  • the reflected light follows path 16 through blue filter 17 to give one color separation image which impinges upon photoconductive drum 18 at point 19.
  • point 19 passes developer station shown generally by reference numeral 20 whereat yellow toner is supplied to the imaged drum surface. Further rotation of drum 3 past the developer station brings the developed imaged drum to point 38 at which the image is transferred to the copy material shown generally by line 35.
  • the light proceeds along path 14 to mirror No. 3 shown by reference numeral 21.
  • the reflected light proceeds along path 22 to mirror No. 2 shown by reference numeral 23.
  • the reflected light proceeds along path 24 through green filter 25 to give a second color separation image which impinges at point 27 on Drum No. 2 shown by reference numeral 26.
  • the remaining charge on its surface cause it to attract red toner at developer station 28 thus producing a developed image on the surface of the drum for transfers to copy material 35 at point 37.
  • Drum No. 1 The other part of the light beam emitted by light splitter No. 1 is used to discharge Drum No. 1 in imagewise fashion.
  • the beam proceeds along path 9 to mirror No. 1 shown by reference numeral 29 whereat it is reflected along path 30 through red color filter 31 to form the third color separation image on the surface of Drum No. 1 (reference numeral 32) at point 33.
  • Drum No. l As Drum No. l is rotated in the direction shown, it passes developer station 34 whereat it is developed with blue toner in imagewise fashion corresponding to the blue component of color original 1. Further rotation past developer station 34 brings the developed image to point 36 at which it is to be transferred to copy material 35.
  • Drum No. 1 after imaging through a red filter and development with blue pigment is imbued with a developed image corresponding to the blue components of the color original.
  • Drum No. 2 after imaging through a green filter and development with a red pigmented toner, has a red image corresponding to the red component of the color original.
  • the Drum No. 2 after imaging through a green filter and development with a red pigmented toner, has a red image corresponding to the red component of the color original.
  • the light beam produced by scanning the color original is simultaneously conducted along optical paths of equal lengths to impinge upon the three photoconductive drums which are caused to rotate at the same lineal speed during imaging, development, transfer, etc. concomitantly, the copy material is moved along the indicated path at a speed which is equal to the speed at which the drums are moving.
  • Drum No. l is moved one half revolution, so that the first point to be imaged at point 33 and the point on the copy material, simultaneously reach transfer station 36.
  • the developed image corresponding to the blue components of the color original is transferred to the copy material as it and Drum No. 1 move in synchronous relationship past point 36.
  • the blue imaged copy material continues to move along the path between points 36 and 37 (shown in FIG. 1 as X Drum No. 2 (shown by reference numeral 26) which is imaged simultaneously with the imaging of Drum No. l is rotated one half revolution by the time the copy material reaches point 37. Since the drums are being simultaneously rotated at the same lineal speed, the lineal distance between imaging point 27 and transfer point 37 of Drum No. 2 must be equal to the sum of one half the circumference of Drum No.
  • Drum No. 2 is transferred to the copy material in perfect registry with the blue toner-developed image previously deposited at point 36.
  • the transfer is effected by imparting a suitable charge by conventional means to the copy material whereby the toner on Drum No. 2 is electrostatically attracted from the drum surface to the copymaterial.
  • Drum No. 3 Since the imaging of Drum No. 3 was simultaneous with the imaging of the other two drums, and, by definition, all drums-are moving at the same lineal speed, the size of Drum No. 3 must be such that one half its:circumference is equal to the distance which the copy web moves in traversing its path between points 35 and38. If this condition is met, then the material will have moved with its two previously imparted images to point 38 in the time that it takes for Drum No. 3 to make one half revolution whereby the'image which is imparted at point 19 and developed at developer station 20 reaches point 38 at the proper time to enable superimposition of the yellow image in perfect registry with the other images.
  • the copy material after being charged by conventional means, receives the yellow developed image in perfect registry with the other two imagesat point 38.
  • the distance between points 37 and 38 (shown as X in FIG. 1) must be such that the sum of X and one half the circumference of Drum No. 2 is equal to one half the circumference of Drum No. 3.
  • the copy material is conducted past a fixing station (not shown) to permanently affix the images thereto and is then collected in a collection station (not shown) at point 39.
  • each drum is cleaned and recharged by conventional means (not shown) in preparation for future reproduction cycles.
  • FIG. 2 which shows the relative movement of two points from start to finish along the copying path versus two points on the respective photoconductive surfaces, one can see graphically the movement of the copy material relative to the movement of the respective drums.
  • the copy web moves at the same lineal speed as the drum surfaces.
  • a first point on the copy material is positioned at the input side of the copy material path.
  • the leading edge of the image indicated by an X is in the 12 oclock position shown respectively by the reference numerals 51A, 51B and 51C.
  • step 2 the leading edge of the copy material (indicated by. a check mark) has moved the distance X bringing it into contact with Drum No. 1, while the trailing edge of the copy material, indicated by a circle appears at point 50.
  • Drum No. l rotates one half revolution thereby bringing the leading edge of the image (X) in contact with the leading edge of the copy material.
  • the image is formed on Drums No. 2 and No. 3; however, in view of the larger size of the latter, the leading edges of the images have not yet reached the path of copy travel.
  • the leading edge has rotated approximately one quarter a revolution to point 52 and in the case of Drum No. 3 the leading edge has rotated approximately one eighth of a revolution to point 53.
  • the trailing edges of the images shown by a dot are located in the 12 o'clock position of the drum.
  • step No. 3 the leading edge of the copy moves the distance X; as Drum No. 2 rotates a further quarter of a revolution bringing the leading edge of the image thereon into contact with the leading edge of the copy at point 54.
  • the travel'of the copy past Drum No. 1 it receives the: image :of thatdrum as both'the drum and the copy move in contact with each other at the same lineal speed. Accordingly, by the time the leading edge of the copy reaches Drum No. 2 it has received the image present on the left half of Drum No. 1. Meanwhile continuing its rotation at the same lineal speed, both the leading and trailing edges of the image on Drum No. 3 have still not reached the copy path although they have approached it to a greater degree than in step 2.
  • step 4 it can be seen that the leading edge of the copy has traversed the distance between the centers of rotation of Drums Nos. 2 and 3.
  • the leading edge of the copy is in contact with the leading edge of the image on Drum No. 3 whereas the trailing edge of the copy has moved past the point of contact with Drum No. 2.
  • the image on Drum No. 3 is transferred to the copy material.
  • step 5 the trailing edge of the copy has reached the transfer point of Drum No. 3 thus traversing the distance X between the centers of rotation of Drums Nos. 2 and 3.
  • the simultaneous continued rotation of Drum No. 3 brings the trailing edge of the image to the point of transfer of the image to the copy thus completing the transfer of the images in registration with each other on the copy material.
  • the optical path between the color original and the three photoconductive surfaces be identical. Once either the optical path length or the size of the drums to be used are decided upon, then the other can be determined.
  • FIG. 3 shows the inversions and reversals which occur as the light beam passes through the lens and various light splitters and mirrors shown in the system represented in FIG. 1. Like numerical designations are used in both FIG. 1 and FIG. 3 to designate various light splitters, mirrors and drums. It can be seen by following the image of the letter E through the separate light paths that the reversals and inversions occasioned by the light splitters and mirrors in each path cause the respective images to arrive at the copy in phase with each other.
  • FIGS. 1, 2 and 3 show an embodiment of the present invention in which three separate photoconductive surfaces are simultaneously imaged by the single light scanning of an original document.
  • the present invention also encompasses systems in which a single continuous photoconductive surface is simultaneously imaged in three areas with a color separation image and each imaged area is separately developed with color toner.
  • the separation images can then be sequentially transferred in registry to a copy material by known means to produce a full color reproduction of the color original.
  • FIG. 4 A schematic representation of such a system is shown in FIG. 4.
  • a color original shown by reference numeral 100 is in position over scanning station 101 consisting of slit 102, lamps 103 and focusing lens 104.
  • monochromatic light splitter No. 1 shown by reference numeral 105
  • monochromatic light splitter No. 2 (106)
  • mirror 107 In the optical path of lens 104 is monochromatic light splitter No. 1 shown by reference numeral 105, monochromatic light splitter No. 2 (106) and mirror 107.
  • Photoconductive belt 108 travels around top guide roller 109 and bottom guide roller 110, in the direction shown, from charging station 111, to exposure stations 112, 113 and 114 respectively, and past developer stations 115, 116 and 117 where powder images are formed by attraction of toner to the charged portions of the photoconductive belt.
  • Copy material (for example, a sheet of paper) is fed into the nip 118 formed between top guide roller 109 and copy roll 119.
  • Transfer of the powder image from the photoconductive belt to the sheet of the support material is effected by means of the corona transfer device 119a that is located at or immediately after the line of contact between the support material and the photoconductive belt.
  • the electrostatic field created by the corona transfer device is effective to tack the support material electrostatically to the belt surface, whereby the support material moves synchronously with the belt while in contact therewith. Simultaneously with the tacking action, the electrostatic field is effective to attract the toner particles comprising the powder image from the photoconductive belt and cause them to adhere electrostatically to the surface of the support material.
  • the support material with the powder image travels past fuser 120 and is taken up by copy take-off rolls 121. Just passed the nip formed by rolls 109 and 119 in the direction of travel of the photoconductor is cleaning brush 122 and photoconductor discharge light 123.
  • the imaging system of FIG. 4 will simultaneously image photoconductor 108 at points 1 12, l 13 and 1 14, if the optical paths between these points and lens 104 are of identical length. Identity of optical paths can be achieved by positioning the photoconductor at the correct angle with respect to the vertical component of the optical path (i.e., 45).
  • Document moves passed slit 102 and reflects an image through slit 102 to lens 104.
  • the light image hits monochromatic light splitter where the image is split into one color separation image which is directed to point 112 on photoconductor 108, and the remainder of the light image is transmitted to light splitter 106.
  • light splitter 105 can be chosen to split off the thirdof the spectrum which is transmitted by a blue filter while transmitting the remaining two-thirds to monochromatic light splitter 106.
  • the image which is split off exposes photoconductor 108 at point 112 with a blue color separation image which will be developed with yellow toner.
  • the two-thirds of the spectrum which impinges upon monochromatic light splitter 106 is separated by the latter into two parts. For example, if light splitter 106 has the property of reflecting the red third of the spectrum, photoconductor 108 at point 113 will form the red color separation image of original copy 100 which should be developed with green color toner.
  • the light source 103 is energized as the original copy is moved passed slit 102.
  • Photoconductor 108 is caused to move in the direction shown passed charging station 1 1 l.
  • the light image passing through lens 104 is split into color separation images which impinge upon photoconductor 108 at points 112, 1.13 and 114 respectively.
  • the charged photoconductor is discharged in imagewise configuration at the three points where light impinges upon it, thus forming three latent images on the photoconductor in the areas indicated by reference letters A, B and C.
  • developer station 115 can be activated to develop image A
  • developer station 116 can be activated to develop image B
  • developer station 117 can be activated to develop image C.
  • a sheet of copy material is fed into nip 1 18 by suitable feed means which keep the sheet on the copy roll for three revolutions of the latter.
  • a uniform charge'is imparted to the sheet to cause it to attract the toner image from the photoconductor.
  • Simultaneous movement of the copy roll in contact with the three imaged areas of the photoconductor causes sequential transfer of the three developed images'to the copy sheet in perfect registration with each other.
  • the imaged copy sheet is removed from the copy roll by suitable take-off means and then conducted passed fuser station 120 to copy take-off rolls 121.
  • the color xerographic system of the present invention thus provides a simplified way for producing full color reproductions of a color original. It is based upon the simple concept that'two or more photoconductive surfaces moving at the same lineal speed can beimaged simultaneously, but transferred sequentially to a copy web if the photoconductive surfaces are of successively larger circumferences.
  • this aspect of the present invention provides a method for storing the image on the second and following photoconductive surfaces while the first photoconductive surface contacts the copy material.
  • the storage capacity is pro vided by the greater distance which the image must travel on the successively larger photoconductive surfaces.
  • the apparatus in essence comprises a series of two or more reproducing stations in the path followed by the copy material. The components of each station are those required to make a monochromatic reproduction of an original, using equipment such as is well known in the art and commercially available.
  • each of the photoconductive surfaces used herein comprises a photoconductive layer on the conductive substrate which can be suitably formed in the shape of a drum or any othercontinuous surface.
  • the surface may also include a'nonphotoconductive layer on the photoconductive surface astaught for'example in commonly assigned U.S. Pat. Nos. 3,146,145 (Kinsella) and 3,25 1,686 (Gundlach).
  • each photoconductive surface of the apparatus of thepresent invention must be subjected to the following operations to complete a reproduction cycle:
  • a photoconductive surface is imbued with a uniform electrostatic charge.
  • An exposure station at which the light beam'isprojected onto the photoconductive surface to dissipate the drum charge in exposed areas thereof and thereby form a latent electrostatic image of the copy to ⁇ be reproduced.
  • a developing station at which a xerographic developing .material including toner particles having an electrostatic charge opposite tothat of the electrostatic latent image, is brought into contact with the photoconductive surface whereby the toner particles adhere to the electrostatic latent image to form a powdered image in the configuration of the copy being reproduced.
  • a transfer station at which the toner powder image is electrostatically attracted from the photoconductive surface to the copy web material.
  • Aphotoconductive cleaning and discharge station at which the photoconductive surface is brushed to remove residual toner particles remaining thereon after the image has been transferred to the copy web and at which the surface is exposed to a relatively bright light source to effect substantially. complete discharge of any residual electrostatic charge remaining thereon.
  • the apparatus of the present invention must comprise one or more stations at which the imaged copy web is subjected to treatment which permanently affixes the image thereto. This result can be accomplished in any of several ways depending upon the nature of the toner. If the toner is a pigmented thermoplastic material, fixation is readily accomplished by passing the imaged copy web through a fusing unit which causes the toner particle to momentarily melt and become permanently affixed to the copy web.
  • the apparatus of this invention must have three separate photoconductive areas simultaneously imaged by light passing through different color filters and developed with a color toner, the color of which is dictated by the color of the filter.
  • Colored toners are well known in the art. They are pigmented thermoplastic materials in particulate form.
  • the thermoplastic material whichforms the matrix of the toner particles can be any homopolymer or copolymer previously used in electrostatographic reproduction processes.
  • a commonly used material is a-copolymer of styrene anda acrylic acid ester containing percent styrene and 35 percent of the acrylate.
  • Other suitable materials are disclosed in U.S. Pat. No.
  • the photoconductive surface may be a continuous belt traveling around two or more rollers between the various stations required for producing and transferring a developed electrostatic image to a copy material.
  • it may be desired to improve copy quality by fixing each color separation image before the next is transferred to the copy material.
  • Filters of other colors than those specifically employed hereinabove may be used.
  • other combinations of mirrors, light splitters and lenses may be substituted for those specifically shown in FIGS. 1 and 4.
  • An electrostatographic reproduction apparatus capable of continuously producing a polychromatic reproduction of a color original comprising: light scanning means for forming a light image of the color original, a single photoconductive surface, means for imparting a uniform charge to said photoconductive surface, optical means for separating the image formed by said light scanning means into at least two separation images, means for conducting said color separation images along different optical paths of equal length to different areas linearly arranged on said photoconductive surface whereby different areas on said surface are simultaneously imaged with different color separation images of the color original, means for separately developing each color separation image with a different marking material, the color of which corresponds to the separation image being developed by said marking material, and means for transferring and affixing the developed images in superimposed relationship onto a copy material.
  • An electrostatographic reproduction apparatus capable of continuously providing a polychromatic reproduction of a color original comprising:
  • a. light scanning means for forming a light image of the color original
  • beam splitting means for separating the light image into at least a first and a second light beam, and then conducting said beams along different optical paths of equal lengths through separate filters of dissimilar colors
  • each optical path c. a continuous photoconductive surface at the terminus of each optical path, each surface being of a predetermined different size and means for moving each surface at the same lineal speed;
  • each succeeding photoconductive surface being equal to the sum of the perimeter of the immediately preceding photoconductive surface plus twice the distance separating the transfer points of the surfaces, measured along the copy web path.
  • An electrostatographic reproduction apparatus capable of continuously producing a polychromatic reproduction of a color original comprising:
  • a. light scanning means for forming a light image of the color original
  • beam splitting means for separating the light image into at least a first and a second light beam, and then conducting said beams along different optical paths of equal lengths through separate filters of dissimilar colors
  • each optical path c. a photoconductive surface at the terminus of each optical path, each surface being of a predetermined different size and means for moving each surface at the same lineal speed;
  • each succeeding photoconductive surface being equal to the sum of the perimeter of the immediately preceding photoconductive surface plus twice the distance separating the transfer points of the surfaces, measured along the copy web path.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Color Electrophotography (AREA)
US126742A 1971-03-22 1971-03-22 Color xerography Expired - Lifetime US3690756A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US12674271A 1971-03-22 1971-03-22

Publications (1)

Publication Number Publication Date
US3690756A true US3690756A (en) 1972-09-12

Family

ID=22426440

Family Applications (1)

Application Number Title Priority Date Filing Date
US126742A Expired - Lifetime US3690756A (en) 1971-03-22 1971-03-22 Color xerography

Country Status (8)

Country Link
US (1) US3690756A (fr)
BE (1) BE781001A (fr)
CA (1) CA963522A (fr)
DE (1) DE2213998A1 (fr)
FR (1) FR2130718B1 (fr)
GB (1) GB1365753A (fr)
IT (1) IT950399B (fr)
NL (1) NL7203733A (fr)

Cited By (32)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4985015U (fr) * 1972-11-13 1974-07-23
US3841751A (en) * 1969-06-04 1974-10-15 Xerox Corp Electrostatic color reproduction method
JPS5099334A (fr) * 1973-12-28 1975-08-07
US3999988A (en) * 1974-07-29 1976-12-28 Xerox Corporation Method for real-time color masking
US4162843A (en) * 1976-12-14 1979-07-31 Ricoh Company, Ltd. Color electrostatic copying machine
EP0004736A2 (fr) * 1978-04-03 1979-10-17 Xerox Corporation Dispositif pour enregistrer ligne par ligne des images de composantes de couleur différentes
US4232961A (en) * 1977-07-22 1980-11-11 Canon Kabushiki Kaisha Image formation apparatus
US4239370A (en) * 1976-12-20 1980-12-16 Minolta Camera Kabushiki Kaisha Electrophotocopying machine for production of colored photocopies
US4286031A (en) * 1978-06-22 1981-08-25 Coulter Stork U.S.A., Inc. Electrostatic multicolor composite printing method and apparatus
WO1982002606A1 (fr) * 1981-01-19 1982-08-05 Kodak Co Eastman Copieur couleur electrophotographique pourvu d'une lentille catadioptre
US4370047A (en) * 1978-04-03 1983-01-25 Xerox Corporation High speed color apparatus
US4410263A (en) * 1982-03-01 1983-10-18 Eastman Kodak Company Sheet handling device for image transfer in an electrographic copier
US4477176A (en) * 1983-12-27 1984-10-16 Eastman Kodak Company Apparatus for producing multiple image simplex and duplex copies in a single pass
US4537493A (en) * 1984-02-01 1985-08-27 Eastman Kodak Company Copy sheet positioning apparatus
EP0163791A1 (fr) * 1984-06-08 1985-12-11 Fuji Xerox Co., Ltd. Appareil xérographique à couleurs
US4577954A (en) * 1983-03-07 1986-03-25 Ricoh Company, Ltd. Two-color copying apparatus
US4593995A (en) * 1984-06-11 1986-06-10 Eastman Kodak Company Method and apparatus for producing multiple sets of copies of a document
US4690542A (en) * 1984-12-29 1987-09-01 Ricoh Company, Ltd. Color copying apparatus
FR2598230A1 (fr) * 1986-05-01 1987-11-06 Ricoh Kk Systeme optique pour copieur en couleurs
EP0320985A2 (fr) * 1987-12-18 1989-06-21 Colorocs Corporation Dispositif vertical d'impression pour appareil électrophotographique
US5027158A (en) * 1987-12-18 1991-06-25 Colorocs Corporation Vertical print engine for electrophotographic apparatus
US5187521A (en) * 1990-03-22 1993-02-16 Canon Kabushiki Kaisha Multicolor image forming apparatus with color component discrimination function
US5243359A (en) * 1991-12-19 1993-09-07 Xerox Corporation Raster output scanner for a multistation xerographic printing system
US5262259A (en) * 1990-01-03 1993-11-16 Minnesota Mining And Manufacturing Company Toner developed electrostatic imaging process for outdoor signs
US5283148A (en) * 1992-09-18 1994-02-01 Minnesota Mining And Manufacturing Company Liquid toners for use with perfluorinated solvents
US5325381A (en) * 1992-12-22 1994-06-28 Xerox Corporation Multiple beam diode laser output scanning system
EP0683436A1 (fr) 1994-05-17 1995-11-22 Minnesota Mining And Manufacturing Company Révélateurs liquides utilisant des solvants hautement fluorés
US5521271A (en) * 1994-09-29 1996-05-28 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US5604070A (en) * 1995-02-17 1997-02-18 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US20030108366A1 (en) * 2001-12-12 2003-06-12 Minolta Co., Ltd. Image forming apparatus
US20050063739A1 (en) * 2003-09-18 2005-03-24 Fuji Xerox Co., Ltd. Image forming device
US20050079435A1 (en) * 2003-10-09 2005-04-14 Motoi Ebizuka Process cartridge and image forming apparatus and method of manufacturing the same

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3206948C2 (de) * 1982-02-26 1986-04-30 Canon K.K., Tokio/Tokyo Fotokopiergerät zur Erzeugung von Mehrfach-Farbkopien
DE3217461C2 (de) * 1982-05-08 1987-01-08 Canon K.K., Tokio/Tokyo Verfahren zur Herstellung von Mehrfarbenkopien sowie Gerät zur Durchführung des Verfahrens
JPH065410B2 (ja) * 1984-04-27 1994-01-19 株式会社東芝 画像形成装置
JPH0690562B2 (ja) * 1985-12-28 1994-11-14 株式会社リコー カラ−複写機
US4803515A (en) * 1986-07-03 1989-02-07 Canon Kabushiki Kaisha Image forming apparatus
JP3515788B2 (ja) * 1991-06-25 2004-04-05 株式会社リコー 書込装置

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986466A (en) * 1955-12-06 1961-05-30 Edward K Kaprelian Color electrophotography
US3292486A (en) * 1962-12-07 1966-12-20 Gretag Ag Apparatus for reversing colour images

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2986466A (en) * 1955-12-06 1961-05-30 Edward K Kaprelian Color electrophotography
US3292486A (en) * 1962-12-07 1966-12-20 Gretag Ag Apparatus for reversing colour images

Cited By (47)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3841751A (en) * 1969-06-04 1974-10-15 Xerox Corp Electrostatic color reproduction method
JPS4985015U (fr) * 1972-11-13 1974-07-23
JPS6137628B2 (fr) * 1973-12-28 1986-08-25 Canon Kk
JPS5099334A (fr) * 1973-12-28 1975-08-07
US3999988A (en) * 1974-07-29 1976-12-28 Xerox Corporation Method for real-time color masking
US4162843A (en) * 1976-12-14 1979-07-31 Ricoh Company, Ltd. Color electrostatic copying machine
US4239370A (en) * 1976-12-20 1980-12-16 Minolta Camera Kabushiki Kaisha Electrophotocopying machine for production of colored photocopies
US4232961A (en) * 1977-07-22 1980-11-11 Canon Kabushiki Kaisha Image formation apparatus
EP0004736A2 (fr) * 1978-04-03 1979-10-17 Xerox Corporation Dispositif pour enregistrer ligne par ligne des images de composantes de couleur différentes
EP0004736A3 (en) * 1978-04-03 1979-10-31 Xerox Corporation An apparatus for line-to-line recording of different color component images
US4370047A (en) * 1978-04-03 1983-01-25 Xerox Corporation High speed color apparatus
US4286031A (en) * 1978-06-22 1981-08-25 Coulter Stork U.S.A., Inc. Electrostatic multicolor composite printing method and apparatus
WO1982002606A1 (fr) * 1981-01-19 1982-08-05 Kodak Co Eastman Copieur couleur electrophotographique pourvu d'une lentille catadioptre
US4371253A (en) * 1981-01-19 1983-02-01 Eastman Kodak Company Color electrophotographic copier
US4410263A (en) * 1982-03-01 1983-10-18 Eastman Kodak Company Sheet handling device for image transfer in an electrographic copier
US4577954A (en) * 1983-03-07 1986-03-25 Ricoh Company, Ltd. Two-color copying apparatus
US4477176A (en) * 1983-12-27 1984-10-16 Eastman Kodak Company Apparatus for producing multiple image simplex and duplex copies in a single pass
US4537493A (en) * 1984-02-01 1985-08-27 Eastman Kodak Company Copy sheet positioning apparatus
EP0163791A1 (fr) * 1984-06-08 1985-12-11 Fuji Xerox Co., Ltd. Appareil xérographique à couleurs
US4580889A (en) * 1984-06-08 1986-04-08 Fuji Xerox Co., Ltd. Color image reproduction apparatus
US4593995A (en) * 1984-06-11 1986-06-10 Eastman Kodak Company Method and apparatus for producing multiple sets of copies of a document
US4690542A (en) * 1984-12-29 1987-09-01 Ricoh Company, Ltd. Color copying apparatus
FR2598230A1 (fr) * 1986-05-01 1987-11-06 Ricoh Kk Systeme optique pour copieur en couleurs
EP0320985A2 (fr) * 1987-12-18 1989-06-21 Colorocs Corporation Dispositif vertical d'impression pour appareil électrophotographique
EP0320985A3 (fr) * 1987-12-18 1990-06-27 Colorocs Corporation Dispositif vertical d'impression pour appareil électrophotographique
US5027158A (en) * 1987-12-18 1991-06-25 Colorocs Corporation Vertical print engine for electrophotographic apparatus
US5262259A (en) * 1990-01-03 1993-11-16 Minnesota Mining And Manufacturing Company Toner developed electrostatic imaging process for outdoor signs
US5187521A (en) * 1990-03-22 1993-02-16 Canon Kabushiki Kaisha Multicolor image forming apparatus with color component discrimination function
US5243359A (en) * 1991-12-19 1993-09-07 Xerox Corporation Raster output scanner for a multistation xerographic printing system
US5283148A (en) * 1992-09-18 1994-02-01 Minnesota Mining And Manufacturing Company Liquid toners for use with perfluorinated solvents
US5325381A (en) * 1992-12-22 1994-06-28 Xerox Corporation Multiple beam diode laser output scanning system
EP0604077A2 (fr) * 1992-12-22 1994-06-29 Xerox Corporation Système de balayage de sortie à diodes laser à plusieurs faisceaux
EP0604077A3 (fr) * 1992-12-22 1994-12-28 Xerox Corp Système de balayage de sortie à diodes laser à plusieurs faisceaux.
US5530067A (en) * 1994-05-17 1996-06-25 Minnesota Mining And Manufacturing Company Liquid toners utilizing highly fluorinated solvents
EP0683436A1 (fr) 1994-05-17 1995-11-22 Minnesota Mining And Manufacturing Company Révélateurs liquides utilisant des solvants hautement fluorés
US5530053A (en) * 1994-05-17 1996-06-25 Minnesota Mining And Manufacturing Company Liquid toners utilizing highly fluorinated solvents
US5663024A (en) * 1994-09-29 1997-09-02 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US5599886A (en) * 1994-09-29 1997-02-04 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US5521271A (en) * 1994-09-29 1996-05-28 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US5753763A (en) * 1995-02-17 1998-05-19 Minnesota Mining And Manufacturing Company Process for preparing liquid toners with hydrocarbon solvents
US5604070A (en) * 1995-02-17 1997-02-18 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US5919866A (en) * 1995-02-17 1999-07-06 Minnesota Mining And Manufacturing Company Liquid toners with hydrocarbon solvents
US20030108366A1 (en) * 2001-12-12 2003-06-12 Minolta Co., Ltd. Image forming apparatus
US6823158B2 (en) * 2001-12-12 2004-11-23 Minolta Co., Ltd. Tandem style color image forming apparatus
US20050063739A1 (en) * 2003-09-18 2005-03-24 Fuji Xerox Co., Ltd. Image forming device
US6938351B2 (en) * 2003-09-18 2005-09-06 Fuji Xerox Co., Ltd. Image forming device
US20050079435A1 (en) * 2003-10-09 2005-04-14 Motoi Ebizuka Process cartridge and image forming apparatus and method of manufacturing the same

Also Published As

Publication number Publication date
DE2213998A1 (de) 1972-09-28
IT950399B (it) 1973-06-20
GB1365753A (en) 1974-09-04
FR2130718A1 (fr) 1972-11-03
FR2130718B1 (fr) 1973-06-29
CA963522A (en) 1975-02-25
NL7203733A (fr) 1972-09-26
BE781001A (fr) 1972-09-21

Similar Documents

Publication Publication Date Title
US3690756A (en) Color xerography
US3697170A (en) Automatic duplexing apparatus
US4660059A (en) Color printing machine
EP0247838A2 (fr) Appareil de transfert
US5019859A (en) Process control for highlight color with developer switching
US4035073A (en) Duplex reproduction machine
US4251154A (en) Electrophotographic color copier
US3970042A (en) Color development apparatus
JPH01189664A (ja) フリンジフリー、３レベルの画像形成方法
JPS6211344B2 (fr)
US4371253A (en) Color electrophotographic copier
US4240723A (en) Process for electrographic image production and an apparatus for carrying out this process
US3848989A (en) Multicolor electrophotographic reproduction device
JPH056033A (ja) 平坦面画像形成方法
US4297422A (en) Electrophotographic process for printing a plurality of copies
US4349268A (en) Electrostatic image-forming process and an apparatus therefor
US4275134A (en) Electrophotographic method for reproducing a multicolor image
JPS59228680A (ja) 電子写真複写機
US5030531A (en) Tri-level xerographic two-color forms printer with slide attachment
US4141728A (en) Transfer of dry developed electrostatic image using plural oppositely charged fields
JPS59111653A (ja) カラ−複写装置
CA1084102A (fr) Methode de transfert
JPH03236070A (ja) 画像形成装置
US5049936A (en) Electrophotographic copier/duplicator having dual imaging apparatus
JPS54115139A (en) Electrophotographic apparatus

Legal Events

Date Code Title Description
AS Assignment

Owner name: NORTHROP CORPORATION, A DEL. CORP.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:NORTHROP CORPORATION, A CA. CORP.;REEL/FRAME:004634/0284

Effective date: 19860516