Patent Abstract:
A method of providing a number approximating a total number of ink drops fired by an imaging device, including the steps of incrementing a COUNT variable associated with a color of ink if an ink drop of that color is fired by a printhead in the imaging device, evaluating the value of the COUNT variable and incrementing a TOTAL INK CONSUMED variable associated with the color, dependent upon the evaluating step.

Full Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an imaging system, and, more particularly, to the storage of the total ink drops fired in an imaging device. 
     2. Description of the Related Art 
     Ink jet printing involves the ejection of tiny ink drops through small nozzles in a controlled manner to create a desired image. Ink is supplied from an ink reservoir to a print head, which includes various passageways from the reservoir to the nozzle orifices. Energy is applied to the ink from an ink droplet generator near each orifice, which may include the application of electrostatic attraction, the application of oscillating forces from piezo-electric elements, the application of heat from heating elements or the like. 
     It is known for ink jet printers to monitor either by actual measurement or by estimation methods the amount of ink used from a printhead. This measurement or estimate of the amount of ink used by a printhead is used by the printer to estimate the remaining amount of ink in the printhead, which is sometimes displayed to indicate the ink supply status or to indicate a low ink supply. A disadvantage of this arrangement is that the information gathered relates to the use of a single printhead. 
     Various methods are used to gather information for sales and marketing relative to the consumption of printheads and use of printers. However, such approaches are based upon sales data and may not be based upon actual usage of printhead cartridges in printers. 
     What is needed in the art is a way to determine, from an ink jet printer, the ink usage data for the entire life of the printer. 
     SUMMARY OF THE INVENTION 
     The present invention provides a method and an apparatus for obtaining and storing the total ink drop fired count for an imaging device over the life of the imaging device. 
     The invention comprises, in one form thereof, a method for providing a number approximating a total number of ink drops fired by an imaging device, including the steps of incrementing a COUNT variable associated with a color of ink if an ink drop of that color is fired by a printhead in the imaging device, evaluating the value of the COUNT variable and incrementing a TOTAL INK CONSUMED variable associated with the color, dependent upon the evaluating step. 
     An advantage of the present invention is that the total ink usage through an ink jet printer is compiled and saved in an imaging device. 
     Another advantage is the implementation of the present invention will provide both marketing and printer usage information not currently available. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a block diagram of an imaging system embodying the present invention; 
     FIG. 2 shows a flow diagram of a process for providing for the storage of a total ink drop fired count for an imaging system shown in FIG. 1; and 
     FIG. 3 shows a flow diagram for a process providing information regarding the total ink drop fired count to the imaging system of FIG.  1 . 
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one preferred embodiment of the invention, in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, and particularly to FIG. 1, there is shown a host based imaging system  10  that includes computer  12 , interface cable  14  and imaging device  16 . Computer  12  is communicatively connected with imaging device  16  by way of interface cable  14  thereby providing communications between computer  12  and imaging device  16 . Of course, appropriate I/O ports may be provided on computer  12  and imaging device  16 . 
     Imaging device  16 , which is an ink jet printer in the embodiment shown, includes nonvolatile memory  18 , volatile memory  20 , front panel interface device  22 , printhead  24 , controller  26  and interconnections  28 ,  32 ,  34  and  36 . 
     Nonvolatile memory  18  may be, for example, electrically erasable programmable read only (EEPROM), read/write compact disk read only memory (CDROM), a floppy disk, a hard disk or flash memory. Nonvolatile memory  18  is communicatively connected to controller  26  by way of interconnection  36 . 
     Volatile memory  20  only has storage capability when power is available to imaging device  16 ; when electrical power is lost volatile memory  20  loses the information stored therein. Volatile memory  20  may consist of, for example, CMOS random access memory (RAM) or any other type of memory requiring power for data retention. Volatile memory  20  is communicatively connected to controller  26  by way of interconnection  34 . 
     Front panel interface device  22  is located on an accessible portion of imaging device  16  providing a user interface for setting parameters of imaging device  16  or receiving information from imaging device  16  and providing the information in a user readable form. Front panel interface device  22  is interconnected with controller  26  by way of interconnection  32 . 
     Printhead  24  contains an ink reservoir and a nozzle plate having nozzle orifices (not shown). It is known to provide printhead  24  with a removable mounting in a carriage assembly in an ink jet printer. The carriage assembly moves printhead  24  in a controlled manner as printhead  24  ejects ink dots therefrom onto paper  30 . Printhead  24  may actually be multiple printheads  24  each with a separate color or printhead  24  may have multi-color capability. Printhead  24  is interconnected with controller  26  by way of interconnection  28 . Interconnection  28  allows controller  26  to send information to printhead  24  thereby controlling the ink jet dots that are ejected from printhead  24 . 
     Controller  26  is interconnected with printhead  24  by way of interconnection  28 ; front panel interface device by way of interconnection  32 ; volatile memory  20  by way of interconnection  34 ; and nonvolatile memory  18  by way of interconnection  36 . Controller  26  is also interconnected with computer  12  by way of interface cable  14 . Controller  26  contains the interface hardware and software necessary to communicate with computer  12  or alternatively to communicate with a network in a manner such that imaging device  16  is embodied as a network printer. Controller  26  may be a microprocessor based control system or alternatively a state machine capable of controlling imaging device  16 . 
     Interconnections  28 ,  32 ,  34  and  36  may each be separately connected to controller  26  or alternatively all or at least some of interconnections  28 ,  32 ,  34  and  36  may be a common bus system. 
     Now additionally referring to FIG. 2, there is depicted a plurality of processor executable process steps, typically executed in a microprocessor, as more fully described below. 
     At the point of beginning of the process and specifically at step  102  nonvolatile memory  18  is initialized. Included in the initialization of nonvolatile memory  18 , in step  102 , a variable TOTAL also known as TOTAL INK CONSUMED is set to zero or a null value. The initializing of nonvolatile memory  18  may be done in a factory environment and may be the state of nonvolatile memory  18  prior to installation in imaging device  16 . 
     Once imaging device  16  is built, the point of beginning of the process is specifically at the point of power up for imaging device  16 , that being step  104 . At step  104 , a variable COUNT is initialized to an initial state, which may be a value of zero. At step  106 , controller  26  determines whether an ink drop has been fired from printhead  24 . If controller  26  determines that no ink drop has been fired the process returns to step  106 . If controller  26  determines that an ink drop has been fired then the process proceeds to step  108 . 
     At step  108 , controller  26  increments the variable COUNT, which may, for example, be accomplished by reading COUNT from volatile memory  20 , adding one to COUNT and storing the result back into volatile memory  20 . At step  110 , controller  26  evaluates the value of variable COUNT and compares it with a predetermined number N. If COUNT exceeds or equals predetermined number N then process flow continues to step  112  else process flow returns to step  106 . 
     If at step  110  COUNT equals or exceeds predetermined value N the process continues to step  112 . At step  112 , variable TOTAL is incremented, which may, for example, be accomplished by controller  26  reading TOTAL from nonvolatile memory  18 , adding one to TOTAL and storing the result back into nonvolatile memory  18 . The process flow then returns to step  104 , which is the point of beginning of the power up start. 
     Now additionally referring to FIG. 3, there is depicted a plurality of processor executable process steps, typically executed in a microprocessor as more fully described below. 
     At the point of beginning of the process, and specifically, at step  122 , controller  26  determines whether a request for the total ink drops fired in imaging device  16  has been received by controller  26 . If controller  26  has received a request for the total ink drops fired in imaging device  16 , then the process continues to step  124 . At step  124 , controller  26  reads variable TOTAL from nonvolatile memory  18  and the process flow continues to step  126 . 
     At step  126 , controller  26  multiplies variable TOTAL by predetermined value N resulting in a value that approximates the total number of ink drops fired during the life of imaging device  16 . The value thus calculated is then sent to the requesting device by controller  26 . 
     Although the foregoing processes, as depicted in FIGS. 2 and 3, are described without reference to a particular color of ink, the processes are carried out for each color contained in printhead  24  or for each color of each printhead  24  if imaging device  16  has multiple printheads  24  with separate colors in each printhead  24 . The implementation of the processes shown in FIGS. 2 and 3, for each color, result in a separate COUNT and a separate TOTAL for each color. This may be accomplished in many ways; for example, an enumerated type of color may be used as an array index, which is utilized in a loop, wherein color is stepped through each of its enumerated elements. 
     An advantage of the present invention is that variable TOTAL is only incremented when the variable COUNT equals or exceeds predetermined number N, which may be 2,000, thereby allowing TOTAL to represent a significant number of fired ink drops. A further advantage is that this allows a memory space in nonvolatile memory to store a larger maximum number, for example, if the memory space is 32 bits long, that memory space can store a maximum count of 2 32 −1, which then would represent (2 32 −1)×2,000 ink drops fired. 
     While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Technology Classification (CPC): 1