Method and system for measuring and compensating for sensitivity and backlash in electrical motors that laterally move printheads in a continuous web inkjet printer
First Claim
1. A method for calibrating electrical motors that move printheads in a printer comprising:
- generating a first plurality of dashes on media with a plurality of printheads as the media moves past the plurality of printheads;
identifying a first position for each printhead in the plurality of printheads from image data of the first plurality of dashes;
operating at least one electrical motor operatively connected to at least one of the printheads in the plurality of printheads to move the at least one printhead in a first direction in the cross-process direction by a predetermined distance;
generating a second plurality of dashes on media with the plurality of printheads as the media moves past the plurality of printheads;
identifying a second position for each printhead in the plurality of printheads from image data of the second plurality of dashes;
comparing the second position of the at least one printhead with the first position of the at least one printhead to measure a distance moved by the at least one printhead;
identifying a first calibration parameter for the at least one electrical motor with reference to the predetermined distance and measured distance; and
operating the at least one electrical motor with reference to the first calibration parameter.
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Accused Products
Abstract
A method of operating a printer enables a controller in the printer to operate electrical motors for aligning printheads in the printer with greater accuracy. The method includes generating a test pattern on media with a plurality of printheads, identifying a first position for each printhead in the plurality of printheads from test pattern image data, operating an electrical motor operatively connected to one of the printheads to move the printhead in a first direction in the cross-process direction by a predetermined distance, generating a second test pattern on the media, identifying a second position for each printhead, comparing the second position of the printhead with the first position of the printhead to measure a distance moved by the printhead, identifying a first calibration parameter with reference to the predetermined distance and measured distance, and operating the electrical motor with reference to the first calibration parameter.
37 Citations
21 Claims
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1. A method for calibrating electrical motors that move printheads in a printer comprising:
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generating a first plurality of dashes on media with a plurality of printheads as the media moves past the plurality of printheads; identifying a first position for each printhead in the plurality of printheads from image data of the first plurality of dashes; operating at least one electrical motor operatively connected to at least one of the printheads in the plurality of printheads to move the at least one printhead in a first direction in the cross-process direction by a predetermined distance; generating a second plurality of dashes on media with the plurality of printheads as the media moves past the plurality of printheads; identifying a second position for each printhead in the plurality of printheads from image data of the second plurality of dashes; comparing the second position of the at least one printhead with the first position of the at least one printhead to measure a distance moved by the at least one printhead; identifying a first calibration parameter for the at least one electrical motor with reference to the predetermined distance and measured distance; and operating the at least one electrical motor with reference to the first calibration parameter. - View Dependent Claims (2, 3, 4, 5)
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6. A method for calibrating electrical motors that move printheads in a printer comprising:
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generating a first plurality of dashes on media with a plurality of printheads as the media moves past the plurality of printheads in a process direction; identifying a first distance between a first identified position for each printhead in the plurality of printheads that is identified from image data of the first plurality of dashes and a target position for each printhead in the plurality of printheads; operating a plurality of electrical motors operatively connected to printheads in the plurality of printheads to move printheads in the plurality of printheads from the first identified positions to the target positions by the first distance identified for each printhead, the printhead movement being in a first direction in a cross-process direction; generating a second plurality of dashes on media with the plurality of printheads as the media moves past the plurality of printheads in the process direction; identifying a second distance moved by each printhead for which an electrical motor was operated to move the printhead from image data of the second plurality of dashes, the identified second distance being between a second identified position for each printhead in the plurality of printheads that is identified from image data of the second plurality of dashes and the first identified position for each printhead in the plurality of printheads; identifying a first calibration parameter for each electrical motor used to move a printhead, the first calibration parameter being identified with reference to the first distance and the identified second distance; and operating the electrical motors for which a first calibration parameter was identified with reference to the first calibration parameter. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A printer comprising:
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a media transport that is configured to transport media through the printer in a process direction; a plurality of printheads configured to eject ink onto media being transported past the plurality of printheads by the media transport; at least one electrical motor operatively connected to at least one printhead in the plurality of printheads; an imaging device mounted proximate to a portion of the media transport to generate image data corresponding to a cross-process portion of the media being transported through the printer in the process direction after the media has received ink ejected from the printheads; and a controller operatively connected to the imaging device, the at least one electrical motor, and the plurality of printheads, the controller being configured to operate the printheads to eject ink onto media to form a first plurality of dashes as the media is being transported past the printheads on the bars, to receive image data of the media and the ink ejected onto the media generated by the imaging device, to operate the at least one electrical motor to move the at least one printhead in a cross-process direction with reference to the media in a first direction, and to process the image data to identify a first calibration parameter for the at least one electrical motor with reference to a first position for the at least one printhead that is identified before the at least one electrical motor is operated to move the at least one printhead and to a second position for the at least one printhead that is identified after the at least one electrical motor is operated to move the at least one printhead. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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Specification