Method and apparatus for detecting anomalous nozzles in an ink jet printer device
AssigneeHewlett-Packard Company
InventorsAntoni Murcia, Xavier Bruch, Josë Luís Valero, Xavier Girones
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Abstract
A method for detecting clogged or otherwise anomalous nozzles in an ink jet printing device having a printer head containing at least one nozzle configured to eject droplets of ink, the method including sending an instruction to the printer head to eject droplets of ink, generating an output signal from a detecting means configured to detect a passage of droplets past the detecting means and applying an algorithm to the output signal which is configurable to check a correct functioning of the nozzles.
Claims21
A method of determining an operating characteristic of a printer head comprising a plurality of nozzles each configured to eject a plurality of droplets of ink, said method comprising the steps of:
- detecting a signal resulting from ejection of a predetermined sequence of ink drops from a selected said nozzle;
- for each of a set of said plurality of said nozzles, detecting a corresponding respective signal resulting from ejection of a corresponding predetermined sequence of ink drops;
- determining a generic signal response from said plurality of detected signal responses of said set of nozzles;
- and
- comparing said detected signal of said selected nozzle with said generic signal determined from said set of nozzles.
A method for checking a functionality of a selected nozzle of a printer head containing a plurality of nozzles configured to eject droplets of ink, said method comprising the steps of:
- sending an instruction to said printer head to eject a predetermined sequence of droplets of ink from said selected nozzle;
- generating an output signal from a detecting means configured to detect a passage of said predetermined sequence of droplets of ink past said detecting means, wherein all of said droplets in said sequence are transiently within a detection zone of said detecting means at a same time;
- and
- applying an algorithm to said output signal to generate an error signal that identifies an anomalous behavior of said selected nozzle.
A method for checking a functionality of at least one selected nozzle of a printer head containing a plurality of nozzles configured to eject droplets of ink, said method comprising the steps of:
- for each nozzle of a set of nozzles of said plurality of nozzles, sending an instruction to a print head to eject a predetermined sequence of ink droplets from said nozzle;
- for each nozzle of said set, generating a corresponding respective output signal from said detecting means;
- and
- applying an algorithm to said output signal to generate an error signal that identifies an anomalous behavior of said at least one selected nozzle,
- wherein said step of applying an algorithm to said output signal comprises the steps of:
- (A) for each of a plurality of sample intervals:
- (i) determining an average output signal of said detecting means for a plurality of output signals corresponding to said set of nozzles;
- (ii) calculating a difference between said average output signal and an output signal of said detecting means corresponding to said at least one selected nozzle;
- and
- (iii) calculating a square of said difference between said average output signal and said output signal of said selected nozzle;
- (B) summing said squared differences for said at least one selected nozzle from said plurality of sample intervals;
- and
- (C) calculating a positive square root of said summed squared differences.
A method for checking a functionality of a selected nozzle of a printer head containing a plurality of nozzles configured to eject droplets of ink, said method comprising the steps of:
- sending an instruction to said printer head to eject a predetermined sequence of droplets of ink from said selected nozzle;
- generating an output signal from a detecting means configured to detect a passage of said predetermined sequence of droplets of ink past said detecting means;
- and
- applying an algorithm to said output signal to generate an error signal that identifies an anomalous behavior of said selected nozzle,
- wherein said step of applying an algorithm to said output signal comprises:
- finding a maximum value of said output signal of said detecting means corresponding to said selected nozzle;
- finding a minimum value of said output signal from said detecting means corresponding to said selected nozzle;
- calculating a peak-to-peak difference value between said maximum output signal value and said minimum output signal value of said selected nozzle;
- for each of a set of said plurality of nozzles located substantially adjacent said selected nozzle, finding a maximum value of an output signal of said detecting means generated in response to a corresponding respective predetermined sequence of ink droplets ejected from each nozzle in said set, and finding a minimum value of said output signal for each nozzle in said set;
- for each nozzle of said set of nozzles, calculating a respective peak-to-peak output signal value;
- calculating an average peak-to-peak value from said plurality of peak-to-peak signal values of said set of nozzles;
- and
- calculating a difference value representing a difference between said peak-to-peak signal value of said selected nozzle, and said average peak-to-peak signal value of said set of nozzles.
A method of determining an operating characteristic of a selected nozzle of an ink jet head device comprising a plurality of nozzles, said method comprising the steps of:
- obtaining for each nozzle of a set of nozzles, a corresponding respective nozzle signal output from a detecting means configured to detect a passage of at least one droplet of ink ejected from said nozzle, thus yielding a plurality of nozzle signals;
- obtaining for a selected nozzle a selected nozzle signal output from said detecting means;
- determining an amount of perturbation signal determined from said plurality of nozzle signals;
- comparing said perturbation signal of said selected nozzle signal with said genetic perturbation signal;
- and
- determining whether said selected nozzle is operating satisfactorily, based on said comparison of perturbation signals.
A method of determining an operating characteristic of an ink jet printer head comprising a plurality of nozzles, said method comprising the steps of:
- for each said nozzle, ejecting a predetermined sequence of ink droplets;
- for a selected said nozzle, generating a corresponding respective perturbation signal having a perturbation produced in response to a said predetermined sequence of ink droplets ejected from said selected nozzle;
- from said perturbation signal of said selected nozzle, generating a magnitude signal representing a magnitude of said perturbation;
- for each of a set of said nozzles, generating a corresponding respective perturbation signal having a perturbation produced in response to a said predetermined sequence of ink droplets ejected from said nozzle;
- generating a generic magnitude signal determined from said plurality of perturbation signals of said set of nozzles;
- and
- for said selected nozzle generating an error signal determined from said magnitude signal of said perturbation of said selected nozzle and said generic magnitude signal.
A method of detecting at least one anomalous nozzle of an ink jet printer device having (a) a plurality of nozzles arranged substantially in at least one row, and (b) a means for detecting a drop of ink ejected from a nozzle, said method comprising the steps of:
- selecting a nozzle of said plurality of nozzles;
- finding a maximum value of an output signal of said detecting means corresponding to said selected nozzle;
- finding a minimum value of said output signal from said detecting means corresponding to said selected nozzle;
- calculating a peak-to-peak difference value between said maximum output signal value and said minimum output signal value of said selected nozzle;
- for each of a set of said plurality of nozzles located substantially adjacent said selected nozzle, finding a maximum value of an output signal of said detecting means generated in response to a corresponding respective predetermined sequence of ink droplets ejected from each nozzle in said set, and finding a minimum value of said output signals for each nozzle in said set;
- for each nozzle of a said set of nozzles, calculating a respective peak-to-peak output signal value;
- calculating an average peak-to-peak signal value from said plurality of peak-to-peak signal values of said set of nozzles;
- and
- calculating a difference between said peak-to-peak signal value of said selected nozzle, and said average peak-to-peak signal value of said set of nozzles.
Dependencies are inferred from the claim text.