Title:
METHOD OF CREATING COLOR TRANSPARENCIES
United States Patent 3833293
Abstract:
A method in which an electrophotographic printing machine creates a multi-color copy of an original document on a support sheet. The multi-color image is transferred from the support sheet to a transparent sheet forming a color transparency.
US Patent References:
Process of printing multicolored pictures
McNett - June 1937 - 2084353
Method of making colored pictures
Pohl - March 1960 - 2927857
IMAGING SYSTEM
Bresnick - December 1970 - 3549447
/3667841.html
Ross - June 1972 - 3667841
COLOR RENDITION METHOD
Fantuzzo - November 1972 - 3702483
Process of printing multicolored pictures
McNett - June 1937 - 2084353
Method of making colored pictures
Pohl - March 1960 - 2927857
IMAGING SYSTEM
Bresnick - December 1970 - 3549447
/3667841.html
Ross - June 1972 - 3667841
COLOR RENDITION METHOD
Fantuzzo - November 1972 - 3702483
Inventors:
Serio, John P. (Webster, NY)
Wieloch, Francis J. (Penfield, NY)
Wieloch, Francis J. (Penfield, NY)
Application Number:
05/381107
Publication Date:
09/03/1974
Filing Date:
07/20/1973
View Patent Images:
Export Citation:
Assignee:
Xerox Corporation (Stamford, CT)
Primary Class:
Other Classes:
355/88, 430/47.400, 355/32, 399/342
International Classes:
G03G13/01; G03F1/00
Field of Search:
355/3,4,17,32,88 96/1.2,30
Primary Examiner:
Horan, John M.
Attorney, Agent or Firm:
Fleischer, Ralabate Green Green H. J. J. C. A. C. A.
Claims:
What is claimed is
1. A method of creating a multi-color copy from a colored original document, including the steps of:
2. A method as recited in claim 1, wherein the backing layer includes preferably a fibrous material.
3. A method of creating a multicolor copy from a black and white original document, including the steps of:
4. A method as recited in claim 3, further including the steps of:
5. A method as recited in claim 4, wherein said step of reproducing the composite multi-color copy includes the steps of:
6. A method as recited in claim 5, wherein said step of laminating includes the steps of:
7. A method as recited in claim 6, wherein said step of reproducing the black and white original document in the first selected color includes the steps of:
8. A method as recited in claim 7, wherein the copy sheet is preferably a substantially transparent sheet.
9. A method as recited in claim 8, wherein the release coating includes preferably a melamine formaldehyde and silicone coating.
10. A method as recited in claim 9, wherein the backing layer includes preferably a fibrous material.
1. A method of creating a multi-color copy from a colored original document, including the steps of:
2. A method as recited in claim 1, wherein the backing layer includes preferably a fibrous material.
3. A method of creating a multicolor copy from a black and white original document, including the steps of:
4. A method as recited in claim 3, further including the steps of:
5. A method as recited in claim 4, wherein said step of reproducing the composite multi-color copy includes the steps of:
6. A method as recited in claim 5, wherein said step of laminating includes the steps of:
7. A method as recited in claim 6, wherein said step of reproducing the black and white original document in the first selected color includes the steps of:
8. A method as recited in claim 7, wherein the copy sheet is preferably a substantially transparent sheet.
9. A method as recited in claim 8, wherein the release coating includes preferably a melamine formaldehyde and silicone coating.
10. A method as recited in claim 9, wherein the backing layer includes preferably a fibrous material.
Description:
The foregoing abstract is neither intended to define the invention disclosed in the specification, nor is it intended to be limiting as to the scope of the invention in any way.
BACKGROUND OF THE INVENTION
This invention relates generally to a method of color reproduction, and more particularly, concerns a method of preparing a color transparency from a black and white or color original.
The process of electrophotographic printing is presently well developed and generally employs an electrostatic latent image recorded on a photoconductive surface which is developed with heat settable toner particles. The toner powder image is tranferred from the electrostatic latent image to a support sheet positioned in contact therewith. Thereupon, the toner power image is permanently affixed to the support sheet. Such a process is described in detail in U.S. Pat. No. 2,297,691 issued to Carlson in 1942.
Multi-color electrophotographic printing is substantially identical to black and white printing, however, rather than forming a total light image of the original document, the light image is filtered producing a single color partial light image. This single color light image exposes the charge photoconductive surface and records a single color electrostatic latent image thereon. The single color electrostatic latent image is developed with toner particles of a color complementary to the single color light image. Thereafter, the single color toner powder image is transferred from the electrostatic latent image to the support sheet. This process is repeated for a plurality of cycles with differently colored light images and the respective complementary color toner particles. Each single color toner powder image is transferred to the support sheet in superimposed registration with the prior toner powder image. In this manner, a composite multi-layered powder image is produced on the support sheet. The multi-color powder image is coalesced and permanently affixed to the support sheet forming a color image thereon.
Although transparencies have heretofore been made by the use of a thermographic process, this has not generally been true for electrophotographic printing machines. Various support sheets have been developed for use in electrophotographic printing machines but these support sheets have generally been opaque and no transparent materials have been widely developed for multi-color electrophotographic printing. Moreover, no technique has as of yet been developed for obtaining color transparencies from a black and white original. Furthermore, no process has been developed wherein a black and white original may be utilized to form a multiplicity of multi-color opaque copies.
Accordingly, it is the primary object of the present invention to improve the method of forming color transparencies from color originals.
An additional object of the present invention is a composite multi-color copy from a plurality of differently colored single color copies reproduced from a single black and white original.
SUMMARY OF THE INVENTION
Briefly stated, and in accordance with the present invention, there is provided a method of creating a multicolor transparency.
Pursuant to the present invention, the method includes producing a multi-color image by an electrophotographic process. The multi-color image is formed on a support sheet having a backing layer and a release coating overlying the backing layer. A transparent sheet is laminated to the surface of the support sheet having the multi-color image thereon. Thereafter, the transparent sheet is separated from the support sheet, the multi-color image being transferred from the support sheet to the transparent sheet. In this manner, a multi-color transparency is formed corresponding to the color original.
Further in accordance with the present invention, a multi-color copy may be created from a black and white original. Initially, a multi-Color transparency is formed which is then utilized as an original to produce color copies therefrom. This is achieved by creating a first single color image of the black and white original on the support sheet. Undesired portions of the single color image are removed from the support sheet. A transparent sheet is then laminated to the surface of the support sheet having the desired portions of the single color image thereon. The transparent sheet is separated from the support sheet transferring thereto the desired portion of the single color image. This process is repeated for successive single color images to form a multicolor transparency from the black and white original. Subsequently, the color transparency is utilized as an original in the multi-color electrophotographic printing machine to create a color copy therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:
FIG. 1 is a schematic perspective view of a multi-color electrophotographic printing machine;
FIG. 2 schematically illustrates the support sheet of the present invention;
FIG. 3 is an elevational view showing a black and white original;
FIG. 4 shows a first single-color image formed on the support sheet from the FIG. 3 black and white original;
FIG. 5 illustrates the desired portions of the first single color image transferred to a transparent sheet;
FIG. 6 depicts a second single color image formed on the support sheet from the FIG. 3 black and white original;
FIG. 7 shows the desired portions of the second single color image transferred to the transparent sheet;
FIG. 8 illustrates a third single color image formed on the support sheet from the FIG. 3 black and white original; and
FIG. 9 depicts the desired portions of the third single color image transferred to the support sheet.
While the present invention will be described in connection with a preferred procedure, it will be understood that it is not intended to limit the invention to that procedure. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be found within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
For a general understanding of the process of electrophotographic printing employing the features of the present invention therein, reference is had to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements. Turning now to FIG. 1, the various components of a multi-color electrophotographic printing machine are illustrated schematically therein. Although the process of creating a multi-color transparency is particularly well-adapted for use in this type of an electrophotographic printing machine, it should become evident from the following discussion that it is equally well-suited for use in a wide variety of printing machines, and is not necessarily limited to the particular embodiment shown herein.
In the subsequent discussion, the general structure of the multi-color electrophotographic printing machine will be discussed. The present invention will be further explained by describing the method of employing the multi-color printing machine to produce color transparencies from a color original. Thereafter, an additional aspect of the present invention will be disclosed, i.e., the method of forming color transparencies and color opaque copies from a black and white original.
Referring now to FIG. 1, the electrophotographic printing machine employs a drum 10 having a photoconductive surface 12 secured to the exterior circumferential surface thereof and entrained thereabout. Drum 10 is mounted rotatably on the machine frame (not shown) and driven at a substantially constant angular velocity, in the direction of arrow 14, by a drive motor (not shown). As drum 10 rotates, photoconductive surface 12 passes sequentially through a series of processing stations. The drive motor rotates drum 10 at a predetermined speed relative to the other operating mechanisms of the printing machine. A timing disc (not shown) mounted in the region of one end of the shaft of drum 10 cooperates with the machine logic to synchronize the various operations with the rotation of drum 10. In this way, the proper sequence of events is produced at the respective processing stations.
First, drum 10 rotates photoconductive surface 12 through charging station A. At charging station A, a corona generating device, indicated generally at 16 extends longitudinally in a transverse direction across photoconductive surface 12. This readily enables corona generating device 16 to spray ions onto photoconductive surface 12 to produce a relatively high, substantially uniform charge thereon. Preferably, corona generating device 16 is of the type described in U.S. Pat. No. 2,778,946 issued to Mayo in 1957.
After photoconductive surface 12 is charged to a substantially uniform potential, drum 10 rotates to exposure station B. Exposure station B is adapted to project a color filtered light image of original document 18 onto charged photoconductive surface 12. A moving lens system, generally designated by the reference numeral 20, and a color filter mechanism shown generally at 22 are located at exposure station B. A suitable moving lens system is disclosed in U.S. Pat. No. 3,062,108 issued to Mayo in 1962. An original document 18, such as a sheet of paper, book, or the like, is placed face down upon transparent viewing platen 24. As will be described hereinafter in greater detail, original document 18 may be a black and white original or a multi-color original. Initially, the description will pertain to a multi-color original. Subsequently, the preparation of multi-color copies from a black and white original utilizing the printing machine of FIG. 1 will be described in detail.
With continued reference to FIG. 1, lamps 26 move in a timed relation with lens 20 and filter mechanism 22 to scan successive incremental areas of original document 18 disposed upon platen 24. This creates a flowing light image of original document 18 which is projected onto photoconductive surface 12. During the exposure process, filter mechanism 20 interposes selected color filters into the optical light path of lens 20. The appropriate filter operates on the light rays transmitted through lens 20 to record an electrostatic latent image on photoconductive surface 12 corresponding to a pre-selected spectral region of the electromagnetic wave spectrum, hereinafter referred to as a single color electrostatic latent image.
Drum 10 next rotates to development station C. Development station C includes three developer units, generally indicated by the reference numerals 28, 30, and 32, respectively. These developer units are arranged to render visible the electrostatic latent image recorded on photoconductive surface 12. Preferably, the developer units are all of the type generally referred to in the art as "magnetic brush developer units." A typical magnetic brush system employs a magnetizable developer mix having carrier granules and toner particles. Generally, the toner particles are heat settable. In operation, the developer mix is continually brought through a directional flux field to form a brush thereof. The electrostatic latent image recorded on photoconductive surface 12 is brought into contact with the brush of developer mix. Toner particles are attracted from the carrier granules of the developer mix to the latent image. Each of the developer units contain toner particles corresponding in color to the complement of the spectral region of the wavelength of light transmitted through filter 22. By way of example, a green filtered electrostatic latent image is developed by depositing green absorbing magenta toner particles thereon. Similarly, blue and red filtered latent images are developed with yellow and cyan toner particles, respectively.
After development, the now visible image is advanced to transfer station D. The toner powder image adhering electrostatically to photoconductive surface 12 is transferred to a support sheet, indicated generally at 34. Support sheet 34 will be described hereinafter in greater detail with reference to FIG. 2. A transfer roll, shown generally at 36, secures support sheet 34 releasably thereto for movement in a recirculating path therewith. Transfer roll 6 is adapted to rotate in synchronism with drum 10 (in this case at substantially the same angular velocity). As shown in FIG. 1, transfer roll 36 rotates in the direction of arrow 38. Thus, successive single color toner powder images may be transferred from photoconductive surface 12 to support sheet 34, each toner powder image being superimposed in registration with the prior one. Image transfer is achieved by electrically biasing transfer roll 36 to a potential having sufficient magnitude and the proper polarity to attract electrostatically toner particles from the latent image recorded on photoconductive surface 12 to support sheet 34. U.S. Pat. No. 3,612,677 issued to Langdon et al. in 1971 depicts a suitable electeically biased transfer roll adapted to effect transfer of the toner particles from the electrostatic latent image recorded on photoconductive surface 12 to support sheet 34.
Prior to proceeding with the description of the remaining process stations associated with the multi-color electrophotographic printing machine illustrated in FIG. 1, the sheet feeding path thereof will be briefly described. A stack 40 of support sheets 34 is disposed on tray 42. Feed roll 44 cooperates with retard roll 46 to separate and advance the uppermost support sheet 34 from the remainder of the sheets of stack 40. The advancing support sheet 34 enters chute 48 which directs it into the nip between register rolls 50. Register rolls 50 align support sheet 34 and move it into engagement with gripper fingers 52 on transfer roll 36. Gripper fingers 52 secure support sheet 34 to transfer roll 36. After a plurality of toner powder images have been transferred to support sheet 34, gripper fingers 52 space support sheet 34 from transfer roll 36 permitting gripper bar 54 to be interposed therebetween. In this manner, gripper bar 54 separates support sheet 34 from transfer roll 36.
Proceeding now with the remaining processes associated with the multi-color electrophotographic printing machine, after transfer, endless belt conveyor 56 advances support sheet 34 to fusing station E. At fusing station E, a fuser, indicated generally by the reference numeral 58, permanently affixes the toner powder image to support sheet 34. One type of suitable fuser is described in U.S. Pat. No. 3,498,592 issued to Moser et al. in 1970. Support sheet 34, with the toner powder image affixed thereto, is, thereupon, advanced by endless belt conveyors 60 and 62 to catch tray 64. Catch tray 64 is arranged to permit the machine operator to readily remove the completed color copy from the printing machine.
The last processing station in the direction of drum 10, as indicated by arrow 14, is cleaning station F. As heretofore indicated, a preponderance of the toner particles are transferred to support sheet 34, however, some residual particles remain on photoconductive surface 12. Cleaning station F removes these residual toner particles from photoconductive surface 12. The residual toner particles are initially brought under the influence of a cleaning corona generating device (not shown) adapted to neutralize the remaining electrostatic charge on photoconductive surface 12 and the residual toner particles. Thereafter, the neutralized toner particles are cleaned from photoconductive surface 12 by a rotating fibrous brush 66. Brush 66 is positioned in contact with photoconductive surface 12. One type of suitable brush cleaning device is described in U.S. Pat. No. 3,590,412 issued to Gerbasi in 1971.
While the electrophotographic printing machine has been described in connection with the formation of a color copy, one skilled in the art will appreciate that the printing machine is not necessarily so limited and that single color copies may be reproduced as well as multi-color copies. A single color copy may be obtained by activating the printing machine in the single color mode. The machine logic, thereupon, regulates the gripping mechanism of the transfer roll such that the support sheet is stripped therefrom after one layer of toner powder is transferred thereto. For example, a magenta copy may be obtained by exposing the photoconductive surface to a green filtered light image. Thereafter, the green electrostatic latent image is developed with magenta toner particles which are then transferred to the support sheet. The support sheet is separated from the transfer roll and the magenta toner particles fused thereto. In a similar fashion, cyan and yellow copies may be created from either a black and white original or a multicolor original. It should be noted that in forming a single color copy from a black and white original it is not necessary to utilize a filter. Hence, a light image of the original is created which irradiates the charged photoconductive surface recording an electrostatic latent image thereon. The latent image is developed with the desired toner particles and transferred to the support sheet. After fusing, the copy is removed from the printing machine. A copy formed in this manner will correspond to the black and white original with the exception that the color thereof will be that of the selected toner particles.
It is believed that the foregoing description is sufficient to illustrate the general operation of a multi-color electrophotographic printing machine employing the support sheet of the present invention therein.
As illustrated in FIG. 2, support sheet 34 is a multi-layer structure comprising backing layer 66 and release layer 68. In the present invention, this structure is used as a support sheet to receive a single layer or a multi-layered toner powder image from photoconductive surface 12 during the transfer operation. Thereafter, the toner powder image is fused to support sheet 34. The image receiving surface, or the toner powder receiving surface is release layer 68. Release layer 68 is incorporated into the structure to facilitate the separation of the toner powder image from backing layer 66. Release layer 68 may be in both surfaces of backing layer 66. Support sheet 34 may be utilized to produce a multi-color image on a transparent sheet. This is achieved by forming the color image on support sheet 34 as heretofore indicated in the multi-color electrophotographic printing machine disclosed in FIG. 1. Thereafter the transparent sheet is laminated to support sheet 34. This laminating process occurs by heating support sheet 34 preferably to about 300°F to facilitate the transfer of the toner powder image to the transparent sheet. After support sheet 34 has attained the desired temperature, the transparent sheet is placed in contact therewith. Release layer 68 permits the toner powder image recorded thereon to be stripped from support 34 and transferred to the transparent sheet.
By way of example, release layer 36 is preferably, a melamine formaldehyde and silicone coating. Backing layer 66 is preferably made from a suitable fibrous material, such as plain paper. The transparent sheet is made of a substantially transparent, non-fibrous material, e.g., a polysulfone thermoplastic, in sheets of about 4 mils thickness. In the alternative, a sheet of polyethylene terephtalate polyester may be used.
While the preferred embodiment of the present invention discusses laminating a transparent sheet to the support sheet having the toner powder image thereon, one skilled in the art will appreciate that the invention is not necessarily so limited. For example, the multi-color toner powder image may be transferred to numerous other types of suitable materials, i.e., wood, cloth, metal, etc. It should be noted, however, that the image formed on an opaque member, i.e. wood, cloth, metal, etc., is reversed from the original. Although the creation of a reversed image is not significant in forming transparencies, i.e., the transparency may simply be appropriately reversed, it may be significant with regard to opaque materials. Accordingly, a first transparency may be formed in manner heretofore described and reversed in the printing machine. A second reversed transparency is formed from the first transparency. The image is then transferred to the opaque material, i.e., wood, cloth, metal, etc. creating a non-reversed color image thereon.
Support sheet 34 has been described in conjunction with the multi-color electrophotographic printing machine for effecting the reproduction of a multi-color original on a transparent sheet. This enables the color image to be projected onto a screen. However, it is apparent to one skilled in the art that a similar process may be utilized to produce a multi-color copy from a black and white original. The process will be described hereinafter with reference to FIGS. 3 through 9, inclusive.
Referring now to FIG. 3, a black and white original 70 is shown therein. Black and white original 70 includes three regions 72, 74 and 76 respectively, each region being designed to be reproduced in a discrete color. By way of example, a plurality of multi-color copies will be created wherein region 72 is cyan, region 74 is magenta, and region 76 is yellow.
Turning now to FIG. 4, there is illustrated a cyan copy of the black and white original depicted in FIG. 3. The cyan copy has been made on support sheet 34 in accordance with the procedure heretofore discussed with reference to the multi-color electrophotographic printing machine of FIG. 1. Each region depicted in FIG. 4 is cyan, i.e., region 72 is cyan, region 74 is cyan, and region 76 is cyan. Thereupon, the operator removes the undesired regions 74 and 76 from support sheet 34 by erasing or simply cutting support sheets 74 along line 78. The desired cyan portion, region 72, of support sheet 34 is laminated, i.e., heated and placed in contact with transparent sheet 80. Transparent sheet 80 is then separated from support sheet 34 and region 72 is transferred thereto, as shown in FIG. 5. Hence, a transparent sheet 80 is depicted in FIG. 5 as having a cyan region 72 thereon, the remaining portion of transparent sheet 80 being blank.
Referring now to FIG. 6, support sheet 34 is shown therein as having regions 72, 74 and 76 reproduced thereon in magenta. As heretofore indicated, the electrophotographic machine described in FIG. 1 produces a single color copy from the black and white original shown in FIG. 3. This single color copy has been selected to be magenta. The undesired magenta portions are removed from support sheet 34 by erasing the undesired portions 72 and 76 or by cutting support sheet 34 along lines 78 and 82. Magenta region 74 is now laminated to transparent sheet 80 adjacent to cyan region 72. When support sheet 34 is separated from transparent sheet 80 the magenta region 74 adheres thereto. Hence, FIG. 7 depicts transparent sheet 80 having a cyan region 72 and a magenta region 74 thereon, the remaining portion of transparent sheet 80 being blank.
Turning now to FIG. 8, a yellow copy of black and white original 70 is reproduced on support sheet 34. This is achieved by placing black and white original 70 in the multi-color electrophotographic printing machine depicted in FIG. 1, the machine being actuated in the single color mode, in this case yellow. As shown therein regions 72, 74 and 76 are yellow. Once again, the undesired regions 72 and 74 are removed from support sheet 34 by erasure or by severing, i.e. cutting, support sheet 34 along line 82. The remaining desired portion, i.e., yellow region 76 is laminated to transparent sheet 80 i.e., heated and placed in contact with transparent sheet 80 adjacent to magenta region 74 thereon. Support sheet 34 is then separated from transparent sheet 80 effecting the transfer of the yellow toner powder image to transparent sheet 80. FIG. 9 depicts transparent sheet 80 as having a cyan region 72, a magenta region 74 and a yellow region 76. This transparency may now be utilized to produce multi-color opaque copies therefrom.
Multi-color transparency 80 is positioned on platen 24 of the electrophotographic printing machine depicted in FIG. 1. The printing machine of FIG. 1 is energized in the multi-color mode hereinbefore described with a stack of conventional support sheets disposed on tray 42 thereof. In this manner, a plurality of multi-color opaque copies may be reproduced from the multi-color transparency 80 heretofore produced from the black and white original 70.
In recapitulation, it is apparent that the present invention provides a process for producing multi-color transparencies from a color original as well as from a black and white original. As heretofore indicated, a multi-color transparency may be created by forming a color image on a support sheet having a release coating thereon. The color image is then transferred to the transparent sheet by laminating the transparent sheet to the support sheet. In this manner, a multi-color transparency is produced from a multicolor original. Similarly, a multi-color copy may be produced from a black and white original. This is achieved by producing successive single color copies on support sheets having a release coating thereon. The undesired portions are removed from the support sheet and the desired portions transferred to the transparent sheet. In this way, successive single color images are transferred to a common transparent sheet producing a multi-color transparency from the black and white original. This multi-color transparency is now employed as an original document in the electrophotogrphic printing machine to produce a plurality of color copies therefrom. In this manner a color transparency or a color copy may be produced from a black and white original.
Thus, it is apparent that there has been provided, in accordance with the present invention, a support sheet that fully satisfies the objects, aims, and advantages set forth above. While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.
BACKGROUND OF THE INVENTION
This invention relates generally to a method of color reproduction, and more particularly, concerns a method of preparing a color transparency from a black and white or color original.
The process of electrophotographic printing is presently well developed and generally employs an electrostatic latent image recorded on a photoconductive surface which is developed with heat settable toner particles. The toner powder image is tranferred from the electrostatic latent image to a support sheet positioned in contact therewith. Thereupon, the toner power image is permanently affixed to the support sheet. Such a process is described in detail in U.S. Pat. No. 2,297,691 issued to Carlson in 1942.
Multi-color electrophotographic printing is substantially identical to black and white printing, however, rather than forming a total light image of the original document, the light image is filtered producing a single color partial light image. This single color light image exposes the charge photoconductive surface and records a single color electrostatic latent image thereon. The single color electrostatic latent image is developed with toner particles of a color complementary to the single color light image. Thereafter, the single color toner powder image is transferred from the electrostatic latent image to the support sheet. This process is repeated for a plurality of cycles with differently colored light images and the respective complementary color toner particles. Each single color toner powder image is transferred to the support sheet in superimposed registration with the prior toner powder image. In this manner, a composite multi-layered powder image is produced on the support sheet. The multi-color powder image is coalesced and permanently affixed to the support sheet forming a color image thereon.
Although transparencies have heretofore been made by the use of a thermographic process, this has not generally been true for electrophotographic printing machines. Various support sheets have been developed for use in electrophotographic printing machines but these support sheets have generally been opaque and no transparent materials have been widely developed for multi-color electrophotographic printing. Moreover, no technique has as of yet been developed for obtaining color transparencies from a black and white original. Furthermore, no process has been developed wherein a black and white original may be utilized to form a multiplicity of multi-color opaque copies.
Accordingly, it is the primary object of the present invention to improve the method of forming color transparencies from color originals.
An additional object of the present invention is a composite multi-color copy from a plurality of differently colored single color copies reproduced from a single black and white original.
SUMMARY OF THE INVENTION
Briefly stated, and in accordance with the present invention, there is provided a method of creating a multicolor transparency.
Pursuant to the present invention, the method includes producing a multi-color image by an electrophotographic process. The multi-color image is formed on a support sheet having a backing layer and a release coating overlying the backing layer. A transparent sheet is laminated to the surface of the support sheet having the multi-color image thereon. Thereafter, the transparent sheet is separated from the support sheet, the multi-color image being transferred from the support sheet to the transparent sheet. In this manner, a multi-color transparency is formed corresponding to the color original.
Further in accordance with the present invention, a multi-color copy may be created from a black and white original. Initially, a multi-Color transparency is formed which is then utilized as an original to produce color copies therefrom. This is achieved by creating a first single color image of the black and white original on the support sheet. Undesired portions of the single color image are removed from the support sheet. A transparent sheet is then laminated to the surface of the support sheet having the desired portions of the single color image thereon. The transparent sheet is separated from the support sheet transferring thereto the desired portion of the single color image. This process is repeated for successive single color images to form a multicolor transparency from the black and white original. Subsequently, the color transparency is utilized as an original in the multi-color electrophotographic printing machine to create a color copy therefrom.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become apparent upon reading the following detailed description and upon reference to the drawings, in which:
FIG. 1 is a schematic perspective view of a multi-color electrophotographic printing machine;
FIG. 2 schematically illustrates the support sheet of the present invention;
FIG. 3 is an elevational view showing a black and white original;
FIG. 4 shows a first single-color image formed on the support sheet from the FIG. 3 black and white original;
FIG. 5 illustrates the desired portions of the first single color image transferred to a transparent sheet;
FIG. 6 depicts a second single color image formed on the support sheet from the FIG. 3 black and white original;
FIG. 7 shows the desired portions of the second single color image transferred to the transparent sheet;
FIG. 8 illustrates a third single color image formed on the support sheet from the FIG. 3 black and white original; and
FIG. 9 depicts the desired portions of the third single color image transferred to the support sheet.
While the present invention will be described in connection with a preferred procedure, it will be understood that it is not intended to limit the invention to that procedure. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be found within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
For a general understanding of the process of electrophotographic printing employing the features of the present invention therein, reference is had to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements. Turning now to FIG. 1, the various components of a multi-color electrophotographic printing machine are illustrated schematically therein. Although the process of creating a multi-color transparency is particularly well-adapted for use in this type of an electrophotographic printing machine, it should become evident from the following discussion that it is equally well-suited for use in a wide variety of printing machines, and is not necessarily limited to the particular embodiment shown herein.
In the subsequent discussion, the general structure of the multi-color electrophotographic printing machine will be discussed. The present invention will be further explained by describing the method of employing the multi-color printing machine to produce color transparencies from a color original. Thereafter, an additional aspect of the present invention will be disclosed, i.e., the method of forming color transparencies and color opaque copies from a black and white original.
Referring now to FIG. 1, the electrophotographic printing machine employs a drum 10 having a photoconductive surface 12 secured to the exterior circumferential surface thereof and entrained thereabout. Drum 10 is mounted rotatably on the machine frame (not shown) and driven at a substantially constant angular velocity, in the direction of arrow 14, by a drive motor (not shown). As drum 10 rotates, photoconductive surface 12 passes sequentially through a series of processing stations. The drive motor rotates drum 10 at a predetermined speed relative to the other operating mechanisms of the printing machine. A timing disc (not shown) mounted in the region of one end of the shaft of drum 10 cooperates with the machine logic to synchronize the various operations with the rotation of drum 10. In this way, the proper sequence of events is produced at the respective processing stations.
First, drum 10 rotates photoconductive surface 12 through charging station A. At charging station A, a corona generating device, indicated generally at 16 extends longitudinally in a transverse direction across photoconductive surface 12. This readily enables corona generating device 16 to spray ions onto photoconductive surface 12 to produce a relatively high, substantially uniform charge thereon. Preferably, corona generating device 16 is of the type described in U.S. Pat. No. 2,778,946 issued to Mayo in 1957.
After photoconductive surface 12 is charged to a substantially uniform potential, drum 10 rotates to exposure station B. Exposure station B is adapted to project a color filtered light image of original document 18 onto charged photoconductive surface 12. A moving lens system, generally designated by the reference numeral 20, and a color filter mechanism shown generally at 22 are located at exposure station B. A suitable moving lens system is disclosed in U.S. Pat. No. 3,062,108 issued to Mayo in 1962. An original document 18, such as a sheet of paper, book, or the like, is placed face down upon transparent viewing platen 24. As will be described hereinafter in greater detail, original document 18 may be a black and white original or a multi-color original. Initially, the description will pertain to a multi-color original. Subsequently, the preparation of multi-color copies from a black and white original utilizing the printing machine of FIG. 1 will be described in detail.
With continued reference to FIG. 1, lamps 26 move in a timed relation with lens 20 and filter mechanism 22 to scan successive incremental areas of original document 18 disposed upon platen 24. This creates a flowing light image of original document 18 which is projected onto photoconductive surface 12. During the exposure process, filter mechanism 20 interposes selected color filters into the optical light path of lens 20. The appropriate filter operates on the light rays transmitted through lens 20 to record an electrostatic latent image on photoconductive surface 12 corresponding to a pre-selected spectral region of the electromagnetic wave spectrum, hereinafter referred to as a single color electrostatic latent image.
Drum 10 next rotates to development station C. Development station C includes three developer units, generally indicated by the reference numerals 28, 30, and 32, respectively. These developer units are arranged to render visible the electrostatic latent image recorded on photoconductive surface 12. Preferably, the developer units are all of the type generally referred to in the art as "magnetic brush developer units." A typical magnetic brush system employs a magnetizable developer mix having carrier granules and toner particles. Generally, the toner particles are heat settable. In operation, the developer mix is continually brought through a directional flux field to form a brush thereof. The electrostatic latent image recorded on photoconductive surface 12 is brought into contact with the brush of developer mix. Toner particles are attracted from the carrier granules of the developer mix to the latent image. Each of the developer units contain toner particles corresponding in color to the complement of the spectral region of the wavelength of light transmitted through filter 22. By way of example, a green filtered electrostatic latent image is developed by depositing green absorbing magenta toner particles thereon. Similarly, blue and red filtered latent images are developed with yellow and cyan toner particles, respectively.
After development, the now visible image is advanced to transfer station D. The toner powder image adhering electrostatically to photoconductive surface 12 is transferred to a support sheet, indicated generally at 34. Support sheet 34 will be described hereinafter in greater detail with reference to FIG. 2. A transfer roll, shown generally at 36, secures support sheet 34 releasably thereto for movement in a recirculating path therewith. Transfer roll 6 is adapted to rotate in synchronism with drum 10 (in this case at substantially the same angular velocity). As shown in FIG. 1, transfer roll 36 rotates in the direction of arrow 38. Thus, successive single color toner powder images may be transferred from photoconductive surface 12 to support sheet 34, each toner powder image being superimposed in registration with the prior one. Image transfer is achieved by electrically biasing transfer roll 36 to a potential having sufficient magnitude and the proper polarity to attract electrostatically toner particles from the latent image recorded on photoconductive surface 12 to support sheet 34. U.S. Pat. No. 3,612,677 issued to Langdon et al. in 1971 depicts a suitable electeically biased transfer roll adapted to effect transfer of the toner particles from the electrostatic latent image recorded on photoconductive surface 12 to support sheet 34.
Prior to proceeding with the description of the remaining process stations associated with the multi-color electrophotographic printing machine illustrated in FIG. 1, the sheet feeding path thereof will be briefly described. A stack 40 of support sheets 34 is disposed on tray 42. Feed roll 44 cooperates with retard roll 46 to separate and advance the uppermost support sheet 34 from the remainder of the sheets of stack 40. The advancing support sheet 34 enters chute 48 which directs it into the nip between register rolls 50. Register rolls 50 align support sheet 34 and move it into engagement with gripper fingers 52 on transfer roll 36. Gripper fingers 52 secure support sheet 34 to transfer roll 36. After a plurality of toner powder images have been transferred to support sheet 34, gripper fingers 52 space support sheet 34 from transfer roll 36 permitting gripper bar 54 to be interposed therebetween. In this manner, gripper bar 54 separates support sheet 34 from transfer roll 36.
Proceeding now with the remaining processes associated with the multi-color electrophotographic printing machine, after transfer, endless belt conveyor 56 advances support sheet 34 to fusing station E. At fusing station E, a fuser, indicated generally by the reference numeral 58, permanently affixes the toner powder image to support sheet 34. One type of suitable fuser is described in U.S. Pat. No. 3,498,592 issued to Moser et al. in 1970. Support sheet 34, with the toner powder image affixed thereto, is, thereupon, advanced by endless belt conveyors 60 and 62 to catch tray 64. Catch tray 64 is arranged to permit the machine operator to readily remove the completed color copy from the printing machine.
The last processing station in the direction of drum 10, as indicated by arrow 14, is cleaning station F. As heretofore indicated, a preponderance of the toner particles are transferred to support sheet 34, however, some residual particles remain on photoconductive surface 12. Cleaning station F removes these residual toner particles from photoconductive surface 12. The residual toner particles are initially brought under the influence of a cleaning corona generating device (not shown) adapted to neutralize the remaining electrostatic charge on photoconductive surface 12 and the residual toner particles. Thereafter, the neutralized toner particles are cleaned from photoconductive surface 12 by a rotating fibrous brush 66. Brush 66 is positioned in contact with photoconductive surface 12. One type of suitable brush cleaning device is described in U.S. Pat. No. 3,590,412 issued to Gerbasi in 1971.
While the electrophotographic printing machine has been described in connection with the formation of a color copy, one skilled in the art will appreciate that the printing machine is not necessarily so limited and that single color copies may be reproduced as well as multi-color copies. A single color copy may be obtained by activating the printing machine in the single color mode. The machine logic, thereupon, regulates the gripping mechanism of the transfer roll such that the support sheet is stripped therefrom after one layer of toner powder is transferred thereto. For example, a magenta copy may be obtained by exposing the photoconductive surface to a green filtered light image. Thereafter, the green electrostatic latent image is developed with magenta toner particles which are then transferred to the support sheet. The support sheet is separated from the transfer roll and the magenta toner particles fused thereto. In a similar fashion, cyan and yellow copies may be created from either a black and white original or a multicolor original. It should be noted that in forming a single color copy from a black and white original it is not necessary to utilize a filter. Hence, a light image of the original is created which irradiates the charged photoconductive surface recording an electrostatic latent image thereon. The latent image is developed with the desired toner particles and transferred to the support sheet. After fusing, the copy is removed from the printing machine. A copy formed in this manner will correspond to the black and white original with the exception that the color thereof will be that of the selected toner particles.
It is believed that the foregoing description is sufficient to illustrate the general operation of a multi-color electrophotographic printing machine employing the support sheet of the present invention therein.
As illustrated in FIG. 2, support sheet 34 is a multi-layer structure comprising backing layer 66 and release layer 68. In the present invention, this structure is used as a support sheet to receive a single layer or a multi-layered toner powder image from photoconductive surface 12 during the transfer operation. Thereafter, the toner powder image is fused to support sheet 34. The image receiving surface, or the toner powder receiving surface is release layer 68. Release layer 68 is incorporated into the structure to facilitate the separation of the toner powder image from backing layer 66. Release layer 68 may be in both surfaces of backing layer 66. Support sheet 34 may be utilized to produce a multi-color image on a transparent sheet. This is achieved by forming the color image on support sheet 34 as heretofore indicated in the multi-color electrophotographic printing machine disclosed in FIG. 1. Thereafter the transparent sheet is laminated to support sheet 34. This laminating process occurs by heating support sheet 34 preferably to about 300°F to facilitate the transfer of the toner powder image to the transparent sheet. After support sheet 34 has attained the desired temperature, the transparent sheet is placed in contact therewith. Release layer 68 permits the toner powder image recorded thereon to be stripped from support 34 and transferred to the transparent sheet.
By way of example, release layer 36 is preferably, a melamine formaldehyde and silicone coating. Backing layer 66 is preferably made from a suitable fibrous material, such as plain paper. The transparent sheet is made of a substantially transparent, non-fibrous material, e.g., a polysulfone thermoplastic, in sheets of about 4 mils thickness. In the alternative, a sheet of polyethylene terephtalate polyester may be used.
While the preferred embodiment of the present invention discusses laminating a transparent sheet to the support sheet having the toner powder image thereon, one skilled in the art will appreciate that the invention is not necessarily so limited. For example, the multi-color toner powder image may be transferred to numerous other types of suitable materials, i.e., wood, cloth, metal, etc. It should be noted, however, that the image formed on an opaque member, i.e. wood, cloth, metal, etc., is reversed from the original. Although the creation of a reversed image is not significant in forming transparencies, i.e., the transparency may simply be appropriately reversed, it may be significant with regard to opaque materials. Accordingly, a first transparency may be formed in manner heretofore described and reversed in the printing machine. A second reversed transparency is formed from the first transparency. The image is then transferred to the opaque material, i.e., wood, cloth, metal, etc. creating a non-reversed color image thereon.
Support sheet 34 has been described in conjunction with the multi-color electrophotographic printing machine for effecting the reproduction of a multi-color original on a transparent sheet. This enables the color image to be projected onto a screen. However, it is apparent to one skilled in the art that a similar process may be utilized to produce a multi-color copy from a black and white original. The process will be described hereinafter with reference to FIGS. 3 through 9, inclusive.
Referring now to FIG. 3, a black and white original 70 is shown therein. Black and white original 70 includes three regions 72, 74 and 76 respectively, each region being designed to be reproduced in a discrete color. By way of example, a plurality of multi-color copies will be created wherein region 72 is cyan, region 74 is magenta, and region 76 is yellow.
Turning now to FIG. 4, there is illustrated a cyan copy of the black and white original depicted in FIG. 3. The cyan copy has been made on support sheet 34 in accordance with the procedure heretofore discussed with reference to the multi-color electrophotographic printing machine of FIG. 1. Each region depicted in FIG. 4 is cyan, i.e., region 72 is cyan, region 74 is cyan, and region 76 is cyan. Thereupon, the operator removes the undesired regions 74 and 76 from support sheet 34 by erasing or simply cutting support sheets 74 along line 78. The desired cyan portion, region 72, of support sheet 34 is laminated, i.e., heated and placed in contact with transparent sheet 80. Transparent sheet 80 is then separated from support sheet 34 and region 72 is transferred thereto, as shown in FIG. 5. Hence, a transparent sheet 80 is depicted in FIG. 5 as having a cyan region 72 thereon, the remaining portion of transparent sheet 80 being blank.
Referring now to FIG. 6, support sheet 34 is shown therein as having regions 72, 74 and 76 reproduced thereon in magenta. As heretofore indicated, the electrophotographic machine described in FIG. 1 produces a single color copy from the black and white original shown in FIG. 3. This single color copy has been selected to be magenta. The undesired magenta portions are removed from support sheet 34 by erasing the undesired portions 72 and 76 or by cutting support sheet 34 along lines 78 and 82. Magenta region 74 is now laminated to transparent sheet 80 adjacent to cyan region 72. When support sheet 34 is separated from transparent sheet 80 the magenta region 74 adheres thereto. Hence, FIG. 7 depicts transparent sheet 80 having a cyan region 72 and a magenta region 74 thereon, the remaining portion of transparent sheet 80 being blank.
Turning now to FIG. 8, a yellow copy of black and white original 70 is reproduced on support sheet 34. This is achieved by placing black and white original 70 in the multi-color electrophotographic printing machine depicted in FIG. 1, the machine being actuated in the single color mode, in this case yellow. As shown therein regions 72, 74 and 76 are yellow. Once again, the undesired regions 72 and 74 are removed from support sheet 34 by erasure or by severing, i.e. cutting, support sheet 34 along line 82. The remaining desired portion, i.e., yellow region 76 is laminated to transparent sheet 80 i.e., heated and placed in contact with transparent sheet 80 adjacent to magenta region 74 thereon. Support sheet 34 is then separated from transparent sheet 80 effecting the transfer of the yellow toner powder image to transparent sheet 80. FIG. 9 depicts transparent sheet 80 as having a cyan region 72, a magenta region 74 and a yellow region 76. This transparency may now be utilized to produce multi-color opaque copies therefrom.
Multi-color transparency 80 is positioned on platen 24 of the electrophotographic printing machine depicted in FIG. 1. The printing machine of FIG. 1 is energized in the multi-color mode hereinbefore described with a stack of conventional support sheets disposed on tray 42 thereof. In this manner, a plurality of multi-color opaque copies may be reproduced from the multi-color transparency 80 heretofore produced from the black and white original 70.
In recapitulation, it is apparent that the present invention provides a process for producing multi-color transparencies from a color original as well as from a black and white original. As heretofore indicated, a multi-color transparency may be created by forming a color image on a support sheet having a release coating thereon. The color image is then transferred to the transparent sheet by laminating the transparent sheet to the support sheet. In this manner, a multi-color transparency is produced from a multicolor original. Similarly, a multi-color copy may be produced from a black and white original. This is achieved by producing successive single color copies on support sheets having a release coating thereon. The undesired portions are removed from the support sheet and the desired portions transferred to the transparent sheet. In this way, successive single color images are transferred to a common transparent sheet producing a multi-color transparency from the black and white original. This multi-color transparency is now employed as an original document in the electrophotogrphic printing machine to produce a plurality of color copies therefrom. In this manner a color transparency or a color copy may be produced from a black and white original.
Thus, it is apparent that there has been provided, in accordance with the present invention, a support sheet that fully satisfies the objects, aims, and advantages set forth above. While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications, and variations as fall within the spirit and broad scope of the appended claims.