Claims
- 1. A method of dynamically adjusting thermal ink-jet printhead drop generator firing energy for a given set of drop generators, the method comprising:monitoring energy accumulation values for each separately addressable set of the drop generators; and adjusting firing energy to addressed drop generators for a next firing sequence based on the energy accumulation values.
- 2. The method as set forth in claim 1, comprising:a) setting a predetermined accumulated energy budget value for each addressable subset of drop generators; b) determining a next drop generator firing sequence; c) setting firing energy for addressed subsets of drop generators based on a function of current accumulated energy budget; d) printing with the next drop generator firing sequence; e) resetting said predetermined accumulated energy budget value for addressed subsets of drop generators as a function of number of nozzles fired in the step of printing as reset accumulated energy budget values; f) repeating steps b) through f) for each firing sequence of a current print job; and g) retaining said reset accumulated energy budget values as said predetermined accumulated energy budget values for a next print job.
- 3. The method as set forth in claim 2, said resetting comprising:said firing energy for an addressed subset is determined by the equation: E*=(PW)(in/n)2(R) where PW=pulse width, i=electrical current=V/R, where V=firing voltage source, R=resistance of each drop generator in the subset, n=number of resistors used in next firing sequence.
- 4. The method as set forth in claim 3, wherein setting firing energy for addressed subsets of drop generators based on a function of current accumulated energy budget further comprises:determining when E1<Em<E2, and setting PW=a and V=b, where E1 and E2 are variables associated with predetermined values of Em, and a and b are predetermined pulse width and supply voltage values, respectively, associated with each of said predetermined values of Em within each range of E1 to E2.
- 5. The method as set forth in claim 4, comprising:determining when Em≧Eeol, where Eeol is a predetermined value indicating an end of printhead life.
- 6. The method as set forth in claim 5, comprising further:providing a signal indicative of end of life of a current printhead.
- 7. The method as set forth in claim 3 the resetting said predetermined accumulated energy budget value for addressed subsets of drop generators as a function of number of nozzles fired in the printing as reset accumulated energy budget values further comprising:Em is reset to reflect the energy experienced during the firing sequence, where: (Em)new=(Em)old+(x/n)(En), where En is the energy seen by each nozzle if all “n” nozzles were fired in the address, and x=actual number of nozzles fired.
- 8. The method as set forth in claim 2, comprising:monitoring each said addressable subset reset accumulated energy budget value; automatically servicing said printhead at predetermined accumulated energy budget values.
- 9. The method as set forth in claim 2, comprising:monitoring each said addressable subset reset accumulated energy budget value; detecting at least one predetermined accumulated energy budget value, Echeck, indicative of a predetermined printhead condition; and sending a signal indicative of a condition of current accumulated energy budget value Em exceeding the predetermined accumulated energy budget value, Em>Echeck.
- 10. A computer memory comprising:computer code for monitoring energy accumulation values for each separately addressable set of drop generators of an ink-jet printhead having a predetermined matrix of drop generators; and computer code for indicating printhead performance characteristics based on the energy accumulation values.
- 11. The computer memory as set forth in claim 10, for a given predetermined accumulated energy budget value for each addressable subset of drop generators, the computer code for monitoring further comprising:computer code for resetting said predetermined accumulated energy budget value for addressed subsets of drop generators as a function of number of nozzles fired in each printing cycle as reset accumulated energy budget values; and computer code for retaining said reset accumulated energy budget values as revised accumulated energy budget values for a next print job, substituting said revised accumulated energy budget values for said given predetermined accumulated energy budget value for each addressable subset of drop generators respectively.
- 12. The computer memory as set forth in claim 11 comprising:computer code for monitoring each said addressable subset reset accumulated energy budget value; computer code for detecting at least one predetermined accumulated energy budget value indicative of a predetermined printhead condition.
- 13. The computer memory as set forth in claim 12, said computer code for indicating printhead performance characteristics based on the energy accumulation values further comprising:computer code for sending a signal indicative of a condition of current accumulated energy budget value exceeding the given predetermined accumulated energy budget value.
- 14. A method for determining printhead life, the method comprising:monitoring energy accumulation data for a first printhead; comparing data derived from said step of monitoring with predetermined energy accumulation data empirically derived for at least one printhead of a substantially comparable printhead type to said first printhead; and predicting remaining printhead life from data derived from said comparing.
- 15. The method as set forth in claim 14 comprising:monitoring each addressable subset of printhead nozzles; detecting at least one predetermined accumulated energy budget value indicative of a predetermined printhead condition related to at least one said subset; and sending a signal indicative of a condition of current accumulated energy budget value, Em, exceeding a predetermined accumulated energy budget value related to said predetermined energy accumulation data empirically derived.
CROSS REFERENCE TO RELATED APPLICATION(S)
This is a continuation of copending application Ser. No. 09/449,239 filed on Nov. 24, 1999 and now U.S. Pat. No. 6,354,687, which is hereby incorporated by reference herein.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
6354687 |
Su et al. |
Mar 2002 |
B1 |
Continuations (1)
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Number |
Date |
Country |
Parent |
09/449239 |
Nov 1999 |
US |
Child |
10/072283 |
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US |