Abstract:
A counterfeit ink detector comprises a color printer calibrated by determining authentic ink color values for several authentic inks used by the color printer. A multi-color pattern is printed using multi-colored inks of a print cartridge. A light source outputs light to the color pattern and a color sensor detects light from the light source reflected from the color pattern. A processor processes the detected light to calculate pattern color values for color components of the color pattern, and compares the pattern color values to the authentic ink color values. A counterfeit ink signal is output by the processor if the difference between the pattern color values and the authentic ink color values is greater than a threshold value indicating counterfeit ink.

Description:
FIELD OF THE INVENTION  
       [0001]     The invention relates to the field of detecting counterfeit ink.  
       BACKGROUND OF THE INVENTION  
       [0002]     Color printers are becoming more popular and are taking over from black and white printers such as monochrome inkjet and dot matrix printers. Moreover, the color quality of the prints made by color printers has become photo-like due to the increase of the number of inks used from the conventional 3 different color inks to as many as 6 or even 8 different color inks.  
         [0003]     The use of more inks has resulted in more expensive ink cartridges thereby providing motivation for counterfeited ink and/or ink cartridges for use in color printers. Counterfeiters refill authentic, but used, ink cartridges with counterfeit inks or else provide an entire counterfeit cartridge with counterfeit inks. Selling printer cartridges and ink is an important source of revenue for printer manufacturers. This counterfeiting has seriously hurt the revenues of printer manufacturers. Moreover, the widespread use of cheap clone ink cartridges and ink refill kits can make the quality of the printer seem poor and hurt the reputation of the printer manufacturer.  
         [0004]     It would be desirable to give a printer the ability to detect when it is being used with counterfeit inks. Such an ability would allow printer manufacturers to stop the use of such counterfeit inks.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides a reliable counterfeit ink detector and counterfeit ink detection method.  
         [0006]     A counterfeit ink detector comprises a color printer calibrated by determining authentic ink color values for several authentic inks used by the color printer. A multi-color print cartridge is inserted into the color printer. A multi-color pattern is printed using multi-colored inks of the print cartridge. A light source outputs light to the color pattern. A color sensor detects light from the light source reflected from the color pattern. A processor processes the detected light to calculate pattern color values for color components of the color pattern, and compares the pattern color values to the authentic ink color values. A counterfeit ink signal is output by the processor if the difference between the pattern color values and the authentic ink color values is greater than a threshold value to therefore indicate that the multi-colored inks of the print cartridge are counterfeit.  
         [0007]     A method for detecting counterfeit ink used by the counterfeit ink detector comprises: calibrating the color printer by determining authentic ink color values for several authentic inks used by the color printer; inserting a multi-color print cartridge into the color printer; printing a multi-color pattern using multi-colored inks of the print cartridge; outputting light to the color pattern from a light source; detecting light from the light source reflected from the color pattern using a color sensor; processing the detected light to calculate pattern color values for color components of the color pattern; comparing the pattern color values to the authentic ink color values; and outputting a counterfeit ink signal if the difference between the pattern color values and the authentic ink color values is greater than a threshold value to therefore indicate that the multi-colored inks of the print cartridge are counterfeit. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  illustrates a configuration of the counterfeit ink detector of the present invention.  
         [0009]      FIG. 2  is a black and white representation of a multi-color test pattern comprising multiple colored squares of different colors used by the invention of  FIG. 1  to detect counterfeit ink.  
         [0010]      FIG. 3  illustrates tabulated data of the differences of xyY values for red, green, blue, cyan, magenta, yellow and gray scale between Hewlett Packard® ink and Saint® ink.  
         [0011]      FIG. 4  is a plot of the delta xyY values of  FIG. 3  vs. the gradient of the colors.  
         [0012]      FIG. 5  is a flowchart of the method for detecting counterfeit ink used by the counterfeit ink detection system of  FIG. 1 .  
     
    
     DETAILED DESCRIPTION  
       [0013]      FIG. 1  illustrates a configuration of a counterfeit ink detection system  101  of the present invention.  FIG. 5  is a flowchart of the method  500  for detecting counterfeit ink used by the counterfeit ink detection system  101 .  
         [0014]     At step  501  a printer  103  is calibrated. The printer can be a HP DESKJET 890c printer, for example. An authentic color ink cartridge  105  is inserted into the printer  103 . The authentic color ink cartridge includes authentic cyan, yellow, magenta and black inks  115 , for example. Here authentic can mean “authorized by the printer manufacturer” or at least can mean that it is not counterfeit.  
         [0015]     Multi-color test pattern data  107  is stored in a storage section  109 . This data  107  is processed by a CPU  111  and used by the printer  103  to print out, using the authentic inks  115 , a multi-color test pattern  201  (see  FIG. 2 ) comprised of multiple colored squares of different colors onto a media  113 .  FIG. 2  is a black and white representation of the actual pattern  201 . The actual pattern  201  includes both the primary colors and secondary colors. The printed primary colors allows the detection of differences in ink color, while the printed secondary colors allows the detection of differences in ink mixing properties. The pattern  201  includes multiple tones of red, blue, green, cyan, yellow and magenta. The media  113  can be paper, for example.  
         [0016]     Next, light  125  is output to the color pattern  201  from a light source  121 . The light source  121  is preferably a broad spectrum source since such a source can capture more information about the pattern  201 . A white LED (light emitting diode) is one such broadband source, although other LED colors or types of light sources can be used. One such white light producing LED can be a blue LED with yellow phosphor. Another type of light source that can be used is an RGB LED where red, green and blue LEDs are combined to produce white light. The choice of light source can be made based on the types of inks used by the printer  103 .  
         [0017]     A color sensor  123  detects light diffusely reflected from the pattern  201 . Preferably the color sensor  123  detects reflected light  127  reflected orthogonally from the pattern  201  and media  113 . The color sensor  123  can be a photo diode or light-to-voltage converter, for example. Also, multiple color sensors can be used in the system. Using more color sensors offers more accurate color detection. The color sensors can use various types of filters coated onto photodiodes, various types of interference filters and can have various shapes.  
         [0018]     The color sensor  123  outputs to the CPU  111  sensor color values  129 . These sensor color values  129  are processed by the CPU  111  to calculate authentic ink color values  131  (x,y, Y coordinates for example) for color components of the color pattern  201  and the authentic ink color values  131  are stored in the storage section  109 . Thus the counterfeit ink detection system  101  is calibrated by programming it with authentic ink color values  131 .  
         [0019]     Alternatively, the calibration step  501  for calibrating the printer  103  can be performed by programming previously determined authentic ink color values  131  into the counterfeit ink detection system  101 . In this way, for given types of ink the same authentic ink color values  131  can be programmed into many different counterfeit ink detection systems  101  associated with many printers so that the full calibration procedure need not be performed for every separate printer.  
         [0020]     The subsequent steps for detecting counterfeit ink can be performed using the same printer  103 , storage device  109 , CPU  111 , light source  121 , and color sensor  123 . In another embodiment, the calibration step  501  is performed using a different printer  103 , storage device  109 , CPU  111 , light source  121 , and color sensor  123 . For example, the authentic ink color values  131  used in the calibration step might be determined from a system at the manufacturer&#39;s location and then used to calibrate a counterfeit ink detection system  101  of a color printer sold to a home or business consumer. In either embodiment, the important thing is that the counterfeit ink detection system  101  is calibrated using the authentic ink color values  131 .  
         [0021]     Next, a step  503  is performed whereby a multi-color print cartridge  141  using cyan, yellow, magenta and black inks  143  is inserted into the color printer  103 . The counterfeit ink detection system  101  is then used to determine whether the multi-color print cartridge  141  is an authentic color ink cartridge or a color ink cartridge using counterfeit ink. The multi-color print cartridge  141  can include all the different inks in a single housing or can comprise separate housings each containing an ink of a different color.  
         [0022]     At step  505 , just as in the calibration step, the multi-color test pattern data  107  stored in the storage section  109  is processed by a CPU  111  and used by the printer  103  to print out, using the inks  143 , the multi-color test pattern  201  (see  FIG. 2 ) comprising multiple colored squares of different colors onto the media  113  (preferably onto a sheet of media  113  different than the sheet of media  113  used in step  501 . Again,  FIG. 2  is a black and white representation of the actual pattern  201 .  
         [0023]     Rather than printing the multi-color test pattern data  107  at step  505 , an actual color image to be printed can be used as a test image. Such an image can be sent to the printer from a personal computer which in turn might receive the image from a scanner, digital camera, storage device, or as a download from the Internet. By using an actual image to be printed rather than the pre-defined multi-color test pattern data  107 , the user does not have to waste paper printing an image that will only be used for counterfeit ink detection. Rather, the image will be one that the user wanted to print out.  
         [0024]     At step  507 , just as in the calibration step, the light  125  is output to the color pattern  201  from the light source  121 .  
         [0025]     At step  509 , just as in the calibration step, the color sensor  123  detects light diffusely reflected from the pattern  201 . The color sensor  123  can be a red-blue-green color sensor and the multi-colored inks  143  can include the colors cyan, yellow and magenta as well as black, for example. In other embodiments the color sensor  123  can be a cyan, yellow, magenta (CYM) color sensor or can be a sensor using other colors.  
         [0026]     At step  511 , the color sensor  123  outputs to the CPU  111  sensor color values  129 . These sensor color values  129  are processed by the CPU  111  to calculate pattern color values  135  for color components (x,y, Y coordinates for example) of the color pattern  201 . The pattern color values  135  are stored in the storage device  109  along with the authentic ink color values  131 .  
         [0027]     At step  513  the pattern color values  135  are compared to the authentic ink color values  131  to determine if the color pattern  201  was printed using counterfeit ink.  
         [0028]      FIG. 3  illustrates tabulated data of the differences of xyY values for red, green, blue, cyan, magenta, yellow and gray scale between Hewlett Packard® ink and Saint® ink.  
         [0029]      FIG. 4  is a plot of the delta xyY values of  FIG. 3  vs. the gradient of the colors.  
         [0030]     From  FIGS. 3 and 4  it is apparent that the present invention distinguishes between different brands of ink.  
         [0031]     At step  515  the counterfeit ink detection systems  101  outputs a counterfeit ink signal if the difference between the pattern color values and the authentic ink color values is greater than a threshold value to therefore indicate that the multi-colored inks  143  of the print cartridge  141  are counterfeit. The counterfeit ink output signal can be used to shut down the printer when the ink  143  is determined to be counterfeit ink. Alternatively or additionally, the counterfeit ink output signal can be used to send a message to the manufacturer of the printer  103  that counterfeit inks  143  are being used. The message can travel to the manufacturer at least in part over the Internet. The counterfeit ink output signal can also be used to provide a warning to a user of the printer  103  that the inks  143  are counterfeit.  
         [0032]     The light source  121  and color sensor  123  used in both the calibration steps and can be embodied in a scanner, integral with the printer  103 , or embodied in some other device.  
         [0033]     In the above system and method, the processing and storage can be performed using a computer such as a personal computer. Alternatively, the processing and storage can be performed by an ASIC can have storage and processing capabilities. The ASIC can come as part of the counterfeit ink detection system  101  or can be a part of the printer  103 .  
         [0034]     In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.