US5644343A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for measuring the temperature of drops ejected by an ink jet printhead
Assignee: Hewlett Packard Development Co LP
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Filing: 1994-12-20
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Granted: 1997-07-01
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Expires: 2014-12-20
Abstract
Abstract The volume of ink drops ejected from ink jet printers is temperature dependent because physical properties of the ink, such as surface tension and viscosity, depend on the ink temperature. The volume of the ejected ink drop strongly influences the size of the printed spot and this size effects the quality of the recorded text and graphics. The temperature of the ejected drop depends on the temperature of the drop ejection mechanism. The present invention measures the temperature of the ejected drops with a temperature sensor placed within the trajectory of the drops. The printhead carriage mechanism aligns the drop ejector and the temperature sensor. Then, the drop ejector ejects multiple drops onto the temperature sensor. The temperature sensor may reside in an ink drop collection chamber having a capillary device for wicking ink away from the temperature sensor to a waste ink accumulator.
Inventors
- 👤 Ross R. Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:27
CPC Classifications
B; B41; B41J; B41J29/00; B41J29/38; B41J2/00; B41J2/005; B41J2/01; B41J2/17; B41J2/195; B41J2/135; B41J2/14; B41J2002/14387
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
99 words
An apparatus for monitoring thermal-inkjet elector temperature, for control of thermal-inkjet print quality, by measuring the temperature of drops ejected by thermal-inkjet printhead; said apparatus comprising: a drop ejector on the thermal-inkjet printhead for ejecting drops to form printed images, said ejector having temperature-dependent print-quality characteristics; and means for monitoring the ejector temperature for control of said print-quality characteristics, said monitoring means comprising: temperature sensor means for measuring the temperature of the drops; means for aligning the drop ejector and the temperature sensor; and means for causing the drop ejector to eject multiple drops onto the temperature sensor means.
Claim 2
Independent Claim
99 words
An apparatus for monitoring thermal-inkjet elector temperature, for control of thermal-inkjet print quality, by measuring the temperature of drops ejected by thermal-inkjet printhead; said apparatus comprising: a drop ejector on the thermal-inkjet printhead for ejecting drops to form printed images, said ejector having temperature-dependent print-quality characteristics; and means for monitoring the ejector temperature for control of said print-quality characteristics, said monitoring means comprising: temperature sensor means for measuring the temperature of the drops; means for aligning the drop ejector and the temperature sensor; and means for causing the drop ejector to eject multiple drops onto the temperature sensor means.
Claim 3
Dependent Claim
57 words
An apparatus, as in claim 1, wherein: the ejected drops have a trajectory; the means for aligning further comprise a means for placing the temperature sensor in the trajectory of the drops; and further comprising a capillary bundle having a first end located near the temperature sensor and a second end located near a waste ink accumulator.
Claim 4
Dependent Claim
40 words
An apparatus, as in claim 1, further comprising: an ink drop collection chamber enclosing the temperature sensor; and wherein the means for aligning the drop ejector and the temperature sensor align the drop ejector with the ink drop collection chamber.
Claim 5
Dependent Claim
29 words
An apparatus, as in claim 3, further comprising: a capillary bundle having one end located near the temperature sensor and a second end located near a waste ink accumulator.
Claim 6
Dependent Claim
28 words
An apparatus, as in claim 4, wherein the means for aligning the drop ejector and the temperature sensor place the temperature sensor in the trajectory of the drops.
Claim 7
Dependent Claim
15 words
An apparatus, as in claim 1, wherein the temperature sensor has a low heat capacity.
Claim 8
Dependent Claim
43 words
The apparatus of claim 1, wherein: the printhead has multiple said drop ejectors; the causing means operate each of the multiple said ejectors independently; and the monitoring means monitor the temperature of each ejector for control of said print-quality characteristics of each ejector.
Claim 9
Independent Claim
144 words
An apparatus for monitoring and controlling thermal-inkjet ejector temperature, for control of thermal-inkjet print quality, by measuring the temperature of drops ejected from a thermal-inkjet printhead; said apparatus comprising: a drop ejector on the thermal-inkjet printhead for ejecting drops along a trajectory to form printed images, said ejector having temperature-dependent print-quality characteristics; a temperature sensor positioned within a range of drop trajectories, the temperature sensor producing an output signal in response to a sensed temperature; means for moving the printhead to align the trajectory of the drops with the temperature sensor; drop ejector controller means for driving the drop ejector to eject drops, the drops striking the temperature sensor and the temperature sensor producing the output signal in response to the temperature of the drops; and means, responsive to the output signal, for controlling the ejector temperature during printing and thereby said print quality.
Claim 10
Independent Claim
144 words
An apparatus for monitoring and controlling thermal-inkjet ejector temperature, for control of thermal-inkjet print quality, by measuring the temperature of drops ejected from a thermal-inkjet printhead; said apparatus comprising: a drop ejector on the thermal-inkjet printhead for ejecting drops along a trajectory to form printed images, said ejector having temperature-dependent print-quality characteristics; a temperature sensor positioned within a range of drop trajectories, the temperature sensor producing an output signal in response to a sensed temperature; means for moving the printhead to align the trajectory of the drops with the temperature sensor; drop ejector controller means for driving the drop ejector to eject drops, the drops striking the temperature sensor and the temperature sensor producing the output signal in response to the temperature of the drops; and means, responsive to the output signal, for controlling the ejector temperature during printing and thereby said print quality.
Claim 11
Dependent Claim
30 words
An apparatus, as in claim 8, further comprising: a capillary bundle having a first end located near the temperature sensor and a second end located near a waste ink accumulator.
Claim 12
Dependent Claim
31 words
An apparatus, as in claim 8, further comprising: an ink drop collection chamber located in the trajectory of the ejected drops, the temperature sensor resides inside the ink drop collection chamber.
Claim 13
Dependent Claim
29 words
An apparatus, as in claim 10, further comprising: a capillary bundle having one end located near the temperature sensor and a second end located near a waste ink accumulator.
Claim 14
Dependent Claim
15 words
An apparatus, as in claim 7, wherein the temperature sensor has a low heat capacity.
Claim 15
Dependent Claim
47 words
The apparatus of claim 8, wherein: the printhead has multiple said drop ejectors; the controller means drive each of the multiple said ejectors independently; and the temperature-controlling means control the temperature of each ejector substantially independently, for control of said print-quality characteristics for each ejector substantially independently.
Claim 16
Independent Claim
73 words
A method for monitoring and controlling the temperature of drops ejected by a drop ejector in a thermal-inkjet printhead, comprising the steps of: aligning the drop ejector with a temperature sensor so that the temperature sensor is in a trajectory of the drops; striking the temperature sensor with the drops ejected from the drop ejector; measuring the temperature of the ink drops; and in response to the measured temperature, controlling the printhead temperature.
Claim 17
Independent Claim
73 words
A method for monitoring and controlling the temperature of drops ejected by a drop ejector in a thermal-inkjet printhead, comprising the steps of: aligning the drop ejector with a temperature sensor so that the temperature sensor is in a trajectory of the drops; striking the temperature sensor with the drops ejected from the drop ejector; measuring the temperature of the ink drops; and in response to the measured temperature, controlling the printhead temperature.
Claim 18
Dependent Claim
26 words
A method, as in claim 14, further comprising the step of: ejecting ink drops until an output temperature of the temperature sensor reaches an equilibrium value.
Claim 19
Dependent Claim
18 words
A method, as in claim 14, further comprising the step of: wicking ink away from the temperature sensor.
Claim 20
Dependent Claim
59 words
A method, as in claim 14, wherein the steps aligning the drop ejector with a temperature sensor and striking the temperature sensor are replaced with the steps: aligning the drop ejector with an ink drop collection chamber that the temperature sensor resides in; and ejecting drops into the ink drop collection chamber until the drops cover the temperature sensor.
Claim 21
Dependent Claim
18 words
A method, as in claim 17, further comprising the step of: wicking ink away from the temperature sensor.
Claim 22
Dependent Claim
51 words
The method of claim 14, particularly for use with such a thermal-inkjet printhead which has multiple said drop ejectors, and wherein: the striking step strikes the sensor with drops ejected from each of the multiple said ejectors, substantially independently; and the temperature-controlling step controls the temperature of each ejector substantially independently.
References Cited (Backward Citations)
JPS58217365A
Cited
EP0562786A2
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-06-30 | 2000-12-30 | 2001-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-06-30 | 2004-12-30 | 2005-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-06-30 | 2008-12-30 | 2009-07-01 | $7700.00 | Window Closed / Lapsed |