Printing device having a printing fluid detector
First Claim
1. A printing device, comprising:
- a printing fluid reservoir configured to hold a volume of a printing fluid;
a print head assembly configured to transfer the printing fluid to a printing medium;
a conduit fluidically connecting the printing fluid reservoir and the print head assembly; and
a printing fluid detector including a first electrode and a second electrode configured to detect an impedance characteristic of the printing fluid, wherein the printing fluid detector is configured to distinguish printing fluid from printing fluid froth by taking an impedance measurement across the first electrode and the second electrode and then comparing the impedance measurement to a froth threshold impedance value that is calibrated to a measured printing fluid temperature.
1 Assignment
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Accused Products
Abstract
A printing device is provided, wherein the printing device includes a printing fluid reservoir configured to hold a volume of a printing fluid, a print head assembly configured to transfer the printing fluid to a printing medium, a conduit fluidically connecting the printing fluid reservoir and the print head assembly, and a printing fluid detector. The printing fluid detector includes first and second electrodes configured to be in contact with the printing fluid, and is configured to distinguish printing fluid from printing fluid froth by taking an impedance measurement across the first and second electrodes and comparing the impedance measurement to a froth threshold impedance value that is calibrated to a measured printing fluid temperature.
50 Citations
68 Claims
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1. A printing device, comprising:
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a printing fluid reservoir configured to hold a volume of a printing fluid; a print head assembly configured to transfer the printing fluid to a printing medium; a conduit fluidically connecting the printing fluid reservoir and the print head assembly; and a printing fluid detector including a first electrode and a second electrode configured to detect an impedance characteristic of the printing fluid, wherein the printing fluid detector is configured to distinguish printing fluid from printing fluid froth by taking an impedance measurement across the first electrode and the second electrode and then comparing the impedance measurement to a froth threshold impedance value that is calibrated to a measured printing fluid temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A printing device, comprising:
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a printing fluid reservoir configured to hold a volume of a printing fluid; a print head assembly configured to transfer the printing fluid to a printing medium; a conduit fluidically connecting the printing fluid reservoir to the print head assembly; and a printing fluid detector having a first electrode and a second electrode configured to be in contact with the printing fluid, wherein the printing fluid detector is configured to take a plurality of impedance measurements across the first electrode and the second electrode, to compute a calculated statistical deviation of the plurality of impedance measurements, and to compare the calculated statistical deviation to a predetermined statistical deviation threshold to determine whether the conduit contains printing fluid froth. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. In a printing device having a printing fluid detector that includes a first electrode and a second electrode configured to be in contact with the printing fluid, a method of determining the presence of printing fluid froth between the first electrode and the second electrode, the method comprising:
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taking a plurality of impedance measurements across the first electrode and the second electrode; determining a measured statistical deviation of the plurality of impedance measurements; and comparing the measured statistical deviation of the plurality of impedance measurements to a predetermined statistical deviation threshold. - View Dependent Claims (39, 40, 41, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 55, 56)
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48. The method of claim 48, wherein the calibrated printing fluid froth threshold value is updated periodically.
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57. In a printing device having a printing fluid detector configured to determine a presence of printing fluid froth in a printing fluid delivery system, wherein the printing fluid detector includes a first electrode and a second electrode configured to be in contact with the printing fluid, a method of distinguishing printing fluid from printing fluid froth, the method comprising:
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taking an impedance measurement across the first electrode and the second electrode; comparing the impedance measurement to a froth threshold impedance value that is calibrated to a measured printing fluid temperature; and if the impedance measurement has a preselected relationship to the froth threshold impedance value, then determining that at least some froth exists between the first electrode and the second electrode. - View Dependent Claims (58, 59, 60, 61)
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62. A printing device, comprising:
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a printing fluid reservoir configured to hold a volume of printing fluid; a print head assembly configured to transfer the printing fluid onto a printing medium; a conduit configured to transport the printing fluid from the printing fluid reservoir to the print head assembly; and a printing fluid detector configured to detect a presence or absence of printing fluid in at least one of the printing fluid reservoir, the conduit and the print head assembly, wherein the printing fluid detector includes a first electrode, a second electrode, and a power supply configured to output a unipolar alternating signal, and wherein the printing fluid detector also includes a bipolar conversion circuit configured to form a bipolar alternating signal using the unipolar alternating signal and to provide the bipolar alternating signal to the first electrode and the second electrode. - View Dependent Claims (63, 64, 65, 66, 67, 68)
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Specification