Patent Publication Number: US-2007097175-A1

Title: Custom color printing apparatus and process

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is a Continuation of pending Utility patent application Ser. No. 10/807,794, filed on Mar. 24, 2004, entitled CUSTOM COLOR PRINTING APPARATUS AND PROCESS and Provisional Patent Application Ser. No. 60/458,789 filed on Mar. 28, 2003, entitled CUSTOM COLOR PRINTING APPARATUS AND PROCESS, commonly assigned to the Eastman Kodak Company. 
    
    
     BACKGROUND OF THE INVENTION  
      The invention relates to the use of custom color inks in printing. In printing, custom colors are often used for accent colors. For use with printing presses, custom color inks are pre-mixed and are typically used for large runs with long setup times for each job. Such pre-mixing of large batches is inefficient for smaller print jobs that make use of custom colors, and setup and cleanup can be difficult and time consuming.  
     SUMMARY OF THE INVENTION  
      According to various aspects of the invention, printing apparatus and processes are provided for dispensing a first primary color ink to a custom color chamber associated with a print head; dispensing a second primary color ink to the custom color chamber; mixing the first primary color ink and the second primary color ink to create a custom color; and printing the custom color ink from the custom color chamber with a print head. A related aspect of the invention is an arrangement of valves for selecting a printing ink from a number of available ink chambers, and feeding the selected ink to a print head. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic block diagram of a custom-color print apparatus.  
       FIG. 2  is a schematic diagram of a custom-color print apparatus including a controller.  
       FIGS. 3   a  and  3   b  are plan views of a valve used in the custom-color print apparatus of  FIGS. 1-2 .  
       FIG. 4  is a partial schematic view of a custom-color print apparatus employing the valves of  FIGS. 3   a  and  3   b.   
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      As illustrated in  FIG. 1 , a custom color print apparatus  10  is provided for feeding custom ink colors to a print head  12  for printing custom accent colors, for example. The print head  12  may be, for example, an inkjet print head. The custom color print apparatus is provided with a number of primary color chambers  14   a ,  14   b , and  14   n  for storing primary color ink (first primary color chamber, second primary color chamber, third primary color chamber, . . . n primary color chambers, where n is an integer number greater than 2). The number of primary color chambers is preferably at least two, but it may be any number as determined by appropriateness for any particular application. The primary color ink may include ink in the colors of cyan, magenta, yellow, black, and white. The term primary color ink as used herein is not limited to a “primary color” as defined under color theory. Rather, the term primary color ink is used herein to include any color of ink that may be mixed with another ink to form a custom color of ink.  
      Dispensing pumps  16   a ,  16   b ,  16   n  are provided to dispense a predetermined quantity (for example metered quantities) of the primary color ink to one or more custom color chambers  20   a ,  20   b ,  20   n  (first custom color chamber, second custom color chamber, third custom color chamber, . . . n custom color chambers, where n is an integer number greater than 1). As illustrated in  FIG. 1 , each custom color chamber is fitted with supply lines from each primary color. The custom color chambers need not be limited to separate containers but may be, for example a region of tubing in which inks are capable of blending.  
      Custom color selectors such as valves  18   a ,  18   b ,  18   n  may be provided to control the flow of primary color ink into the custom color chambers to ensure that primary color ink pumped by the dispensing pumps is directed into a selected one of the custom color chambers  20   a ,  20   b ,  20   n . One or more of the valves  18   a ,  18   b ,  18   n  may comprise a dispensing valve operative to dispense a predetermined quantity (for example metered quantities) of ink into the custom color chamber, for example a low-resolution, low speed inkjet nozzle such as a Lee Valve (VHS-Lt Direct Dispensing Micro-Drop Valve, The Lee Company, Westbrook, Conn.), which can be used to put drops of primary color ink in the custom color chambers  20   a ,  20   b ,  20   n . One such valve may be provided for each line leading from the primary color chambers to the secondary color chambers (e.g., an individual valve  18   a , and/or  18   b , . . . and/or  18   n , may include two, three, or more Lee Valves, one for each of the primary color chambers  14   a ,  14   b , and  14   n ).  
      Although three custom color chambers and three primary color chambers are illustrated in  FIG. 1 , the number of primary color chambers and custom color chambers need not be the same. In one embodiment, five primary color chambers might be used in conjunction with a single custom color chamber.  
      The custom color chambers  20   a ,  20   b ,  20   n  may be provided with one or more mixers (not illustrated), which may be, for example, mechanical, magnetic, pneumatic, hydraulic, or ultrasonic stirrers, powered by electricity or other suitable source. The custom color chambers may be removable for storage outside the color print apparatus, and/or to enable swapping of custom colors. Moreover, the custom color chambers may be disposable to simplify cleanup when a new custom color is desired. Preferably, where a previously-mixed color is obtained (such as a color mixed outside of the print apparatus), a chamber containing that color can be added to the print apparatus.  
      The custom color chambers  20   a ,  20   b ,  20   n  are associated with the print head  12 . When printing is performed using custom colors, one or more feed pumps  22   a ,  22   b ,  22   n  feed custom color ink from the custom color chambers  20   a ,  20   b ,  20   n  through feed valves  24   a ,  24   b ,  24   n  to the print head  12 .  
      A source of purging fluid is provided, such as a reservoir  21  with a pump  23  to pump the purging fluid through the portions of the color print apparatus such as the feed valves  24   a ,  24   b ,  24   n  and the print head  12 . The purging fluid pump is operative to direct purging fluid from the purging fluid reservoir  21  to the feed valves  24   a ,  24   b ,  24   n . The feed valves are operative to alternatively direct purging fluid from the purging fluid pump  23  or ink from a corresponding custom color chamber  20   a ,  20   b ,  20   n  to the print head  12 . The purging fluid is used to clear one color of ink from the print apparatus when it is desired to switch to another color of ink, thereby preventing different ink colors from mixing unintentionally. The print apparatus can be purged by printing ink to a waste receptacle or to the receiver. The feed valves  24   a ,  24   b , and  24   n  may be provided with bleed lines (illustrated in groups of three)  26   a ,  26   b , and  26   n  to release purging fluid and/or excess ink from the apparatus.  
      The pumps in the apparatus may be systolic pumps. The term “pump,” as used herein is broadly used to encompass various arrangements for propelling liquid, such as an arrangement for providing a pressure gradient or a gravity-feed arrangement.  
      A schematic illustration of the print apparatus is provided in  FIG. 2 . Primary color chambers  14   a  and  14   b  are shown, together with dispensing pumps  16   a  and  16   b , both of which feed to the valve  18   a  leading to the custom color chamber  20   a . A feed tube  56  passes from the custom color chamber  20   a  through a wiper  58  to the feed pump  22   a . The feed pump  22   a  draws the custom color through the feed tube  56  and provides it, through the valve  24   a , to the print head  12 . Additional components of the print apparatus, such as additional primary and/or custom color chambers and associated valves, are not illustrated in  FIG. 2  for simplicity.  
      The print apparatus is preferably operated under the control of a controller  50 , which may include a central processing unit (CPU), such as the CPU of a general-purpose computer programmed by software to operate the print apparatus, or a special-purpose computer or logic circuit designed to operate the print apparatus. The controller may accept an input indicating one or more custom colors to be used by the print apparatus. The input may accept a color identification through, for example, RGB value or Pantone number, or the input may include an optical scanner that reads a color sample to create a match, or the input may receive a formula that identifies proportions for mixing primary color inks to form a custom color. As the print head  12  prints on a receiver  52 , such as a sheet of paper, a print color sensor  54  may detect the color printed by the print head  12 . This sensing may be used to verify the changing of the color of ink printed by the print head  12 , and the constancy of the ink color during print jobs. An ink color sensor  86  may be positioned to sense a color of ink in the custom color chamber. The sensors  52  and  86  may be optical sensors, for example, or any sensor suitable for sensing a print or ink color, respectively.  
      Based on the readings from the print sensor  54  and/or the ink sensor  86 , the controller  50  may make corrections to the custom colors. The print apparatus may, for example, print one or more proofs monitored by the sensor  54 , with the controller  50  controlling a cycle that may include adjusting the custom color ink, purging, and printing until the detected color on the page matches a desired custom color. The print sensor  54  may also be used to measure the color of the custom color portions of the image during print jobs. If this custom color varies from the specified color, it can be corrected during the print job by the controller  50 . The controller  50  may be operative to induce dispensing of ink from one or more of the primary color chambers  14   a ,  14   b ,  14   n  into the custom color chamber  20   a ,  20   b ,  20   n  in order to match a color printed by the print head  12  to a predetermined print color with feedback from the print sensor  54 . In similar manner, the controller  50  may be operative to induce dispensing of ink from one or more of the primary color chambers  14   a ,  14   b ,  14   n  into the custom color chamber  20   a ,  20   b ,  20   n  in order to match the color of ink in the custom color chamber  20   a ,  20   b ,  20   n  to a predetermined custom color of ink with feedback from the ink sensor  86 . The controller  50  may be operative to report the color of ink in the custom color chamber  20   a ,  20   b ,  20   n , and/or the color printed by the print head  50 , to a print apparatus operator.  
      The print sensor  54  may be implemented to verify the changing of the color of ink printed by the print head. A change of the custom color to another custom color may be verified by printing the purging fluid and/or the another custom color on at least one receiver with the print head  50 . The printing process may comprise directing the at least one receiver to a different destination than a bulk of receivers printed with the custom color, for example for proofing, or to a waste receptacle. The apparatus operator may verify the color change, or the controller  50  may be operative to verify the color change with feedback from the print sensor  54 .  
      The primary color chambers  14   a ,  14   b ,  14   n , color chambers  20   a ,  20   b ,  20   n , and the purging fluid reservoir  21  may be provided with low-level sensors (not shown) to indicate when fluid levels are low. The controller  50  may be operative to halt printing by the print head  12  in response to the at least one low level sensor sensing a low fluid level and to notify a print apparatus operator.  
      Multiple sets of the custom color printing apparatus  10 , each with at least one print head, may be included in a printing machine to print color separations sequentially in register on the receiver. These separations may contain primaries C,M,Y,K, custom colors, or other color sets, such as for duotones.  
      The valves of the apparatus are selected so that they do not retain fluid and are easily purged. They can be controlled by, for example, stepper motors or solenoids operated by the controller. One type of valve that is well adapted for use in the print apparatus as a feed valve, such as one or more of the valves  24   a ,  24   b , and  24   n , is illustrated in  FIGS. 3   a  and  3   b . The valve  24   a  includes external ports  70 ,  72 ,  74 ,  76 ,  78 ,  80 ,  82 , and  84 . The valve  24   a  also includes internal ports  73 ,  75 ,  79 , and  83 . The rotary portion of the valve contains straight passages  71  and  81 . In the view shown in  FIGS. 3   a  and  3   b , passage  71  and  81  are at different levels, and passage  71  crosses over passage  81 . Correspondingly, passage  71  is shown with heavily dashed lines and passage  81  is shown with lines having alternating dashed and dotted sections. The level of the other passages in the valve is indicated by like-dotted lines. For example, the passage from external port  74  to external port  84  is at the level of passage  81 . The openings of internal ports  73 ,  75 ,  79 , and  83  are enlarged to connect to openings in the rotary portion of the valve at either the level of passage  71  or the level of passage  81 .  
       FIG. 3   a  illustrates the feed valve  24   a  in the bleed/prime position. The ports  72  and  74  are coupled to the purging fluid pump  23 , the ports  76 ,  78 , and  80  are coupled to the bleed lines  26   a  (see  FIG. 1 ), and the ports  82  and  84  are coupled to the next feed valve  24   b . In the bleed/purge position of  FIG. 3   a , the ports  70 ,  74 , and  84  are all coupled to the bleed lines, while the port  72  flows to the port  82 .  
       FIG. 3   b  illustrates the valve  24   a  in the feed position. In the feed position, the ports  72 ,  74 , and  84  are coupled to the bleed lines, while the port  70  flows to the port  82 . When the valve  24   a  is in either the feed position or in the bleed/prime position, a portion of the purging fluid fed into the port  74  flows out of the port  84 , and a portion of the purging fluid fed into the port  74  pressurizes and purges the internal passages in the valve  24   a  that are not connected to the ports  72 ,  82 , or  70 . These passages are purged through the ports  76  and  80 , which are coupled to the bleed lines  26   a  (see  FIG. 1 ). Modifications and additions can be made to the valve arrangement shown in  FIGS. 3   a  and  3   b  to adapt the system for long idle periods, evaporative ink, or infrequent ink changes. For example, the ports  76 ,  78 , and  80  may be fitted with solenoid valves or other automated valves, and purging can be done at intervals. Port  70  may be fitted with a one-way valve only allowing passage of ink into valve  24   a . Passage  71  may be eliminated and the openings of internal ports  73  and  79  sized to connect only at the level of passage  81  if ink from port  70  is to be purged through the print head or through other ports downstream from port  84 .  
       FIG. 4  illustrates the valves  24   a ,  24   b , and  24   n  implemented in a print apparatus. In  FIG. 4 , the color associated with the pump  22   b  is the selected printing color. To print using the color associated with the pump  22   b , the valve  24   b  is arranged in the feed position (see  FIG. 3   b ). The remaining valves in the apparatus are arranged in the bleed/prime position (see  FIG. 3   a ). In this arrangement, when custom color ink is pumped by the selected pump  22   b , the ink is directed by the valve  24   b  to the print head  12 . Any flow from the unselected color pumps  22   a ,  22   n  and from the purging fluid pump  23  is directed to one or more of the bleed lines  26   a ,  26   b ,  26   n . The flow of the ink and purging fluid is illustrated in part by arrows drawn through the valves  24   a ,  24   b , and  24   n . (Arrows are omitted from other potential fluid paths to enhance readability.) The line or tube connecting the ports  72   a ,  72   b ,  72   n  and  82   a ,  82   b ,  82   n  is the main ink line and can contain either ink, purge fluid, or a mixture of ink and purge fluid in normal operation. The line or tube connecting the ports  74   a ,  74   b ,  74   n  and  84   a ,  84   b ,  84   n  is an auxiliary line that contains purge fluid in normal operation.  
      The color print apparatus operates as follows, with steps that may be taken under the direction of the controller  50 :  
      To purge custom colors, the feed valves are set to bleed/prime, the custom colors chambers are pumped at bleed pressure or bleed speed (low speed), and purging fluid is run through the print head until the output is clear.  
      To make a new custom color, controlled amounts of primary color ink are provided to one of the custom color chambers and are mixed or allowed to mix.  
      To start printing the new color from a custom color chamber (e.g., the chamber  20   b ), the color is primed, the associated feed valve  24   b  is set to feed, and the ink is pumped at purging speed through the print head. When the print head is loaded with the new color, printing is started. All other valves ( 24   a and  24   n ) are set to bleed/prime. The valve  24   n  will pass fluid sent through the upstream valves to print head  12 . Passages in valve  24   n  that are not connected to print head  12  are purged to the bleed lines  26   n  or pass ink from deselected color pump  22   n  to the bleed lines  26   n . The purging fluid is fed at bleed pressure or bleed speed. Passages in valves that are set to feed or are set to bleed/prime are filled with either purge fluid, ink, or a mixture of purge fluid and ink. The passages in valves  26   a ,  26   b , and  26   n  are always filled with fluid so that changing valve settings does not introduce air bubbles into the ink lines. In such manner, the feed valves  24  are operative to alternatively direct purging fluid from the purging fluid source  21 / 23  or ink from the custom color chamber  20  to the print head  12  without generating bubbles in the feed valve.  
      To use a premixed color, one of the custom color chambers (such as chamber  20   a ) is removed and the feed tube  56  is cleaned as necessary, possibly during removal by the wiper  58  or a sponge or squeegie attached to the chamber. While the chamber  20   a  is removed, pumping from that chamber is disabled. The premixed color chamber with the desired color is installed and the new color is primed. This can be done during a printing operation.  
      The controller  50  and supporting software are implemented to control the various functions described herein. Such implementation is well within ordinary skill in the relevant art. It should be understood that the programs, processes, methods and apparatus described herein are not related or limited to any particular type of computer or network apparatus (hardware or software), unless indicated otherwise. Various types of general purpose or specialized computer apparatus may be used with or perform operations in accordance with the teachings described herein. The control implementation may be expressed in software, hardware, and/or firmware.  
      Although the invention has been described and illustrated with reference to specific illustrative embodiments thereof, it is not intended that the invention be limited to those illustrative embodiments. Those skilled in the art will recognize that variations and modifications can be made without departing from the true scope and spirit of the invention as defined by the claims that follow. It is therefore intended to include within the invention all such variations and modifications as fall within the scope of the appended claims and equivalents thereof. The claims should not be read as limited to the described order or elements unless stated to that effect. In addition, use of the term “means” in any claim is intended to invoke 35 U.S.C. §112, paragraph 6, and any claim without the word “means” is not so intended.  
      The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.