US5659342A
Expired / Lapsed
US
⏱️ 0.0 years remaining
On-page inkjet printhead spitting system
Assignee: Hewlett Packard Development Co LP
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Filing: 1994-09-30
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Granted: 1997-08-19
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Expires: 2014-09-30
Abstract
Abstract An on-page inkjet printhead spitting system purges the printhead nozzles across the printed page, and occasionally in the conventional service station spittoon. In addition to the image-forming droplets, extra purging droplets are fired to maintain pen health. To determine when to purge each nozzle, the number of times each nozzle is fired to print the image is counted or estimated, or printhead characteristics are monitored. The purging dots may be located on the page, in the spittoon, or both. On the page, the purging dots may be hidden from view, in the image background or over the image dots, or hidden in plain sight adjacent image dots, in speed bars, in a watermark type design, or in a repeating pattern. Use of this on-page spitting system conserves ink and improves throughput of the printing mechanism, without requiring any sacrifice in the print quality appearance to the naked eye.
Inventors
- 👤 Mark D. Lund
- 👤 Jefferson P. Ward
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:11
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/135; B41J2/165; B41J2/16517; B41J2/1652; B41J2/16526; B41J2/16529; B41J2002/1657
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
64 words
A method of purging an inkjet printhead used in an inkjet printing mechanism, comprising the steps of: firing selected nozzles of the printhead to deposit image ink droplets on a print media page to print a selected image; purging selected nozzles by firing to deposit purging ink droplets on the page; and blending the purging ink droplets into a background portion of the page.
Claim 2
Independent Claim
64 words
A method of purging an inkjet printhead used in an inkjet printing mechanism, comprising the steps of: firing selected nozzles of the printhead to deposit image ink droplets on a print media page to print a selected image; purging selected nozzles by firing to deposit purging ink droplets on the page; and blending the purging ink droplets into a background portion of the page.
Claim 3
Dependent Claim
27 words
A method according to claim 1, further comprising the step of locating the purging ink droplets on the page in a blank space without image ink droplets.
Claim 4
Dependent Claim
37 words
A method according to claim 2, further comprising the steps of: analyzing the firing required of each nozzle to print the image; selecting the nozzles in need of purging; and conducting the firing and purging steps concurrently.
Claim 5
Dependent Claim
25 words
A method according to claim 1, wherein the purging step comprises locating purging ink droplets in a pattern along two opposing edges of the page.
Claim 6
Dependent Claim
23 words
A method according to claim 1, wherein the blending step comprises randomly distributing the purging droplets in the background portion of the page.
Claim 7
Dependent Claim
42 words
A method according to claim 1, wherein: each droplet has a dot width when deposited on the page; and the blending step comprises the step of locating each purging ink droplet at least three dot widths away from other purging ink droplets.
Claim 8
Dependent Claim
44 words
A method according to claim 1, wherein: the method further includes the step of counting the number of image ink droplets fired from each nozzle; and the purging step responds to the counting step by firing purging droplets from nozzles in need of purging.
Claim 9
Dependent Claim
73 words
A method according to claim 1, further comprising the steps of: monitoring the number of image ink droplets fired by each nozzle; comparing the monitored number of image droplets fired with a selected standard number; and in response to the comparing step, firing a number of purging ink droplets from each nozzle so the sum of the numbers of purging and image ink droplets for each nozzle substantially exceeds the selected standard number.
Claim 10
Dependent Claim
18 words
A method according to claim 8, wherein the comparing step is repeated at selected time intervals during printing.
Claim 11
Dependent Claim
17 words
A method according to claim 1, wherein the purging step comprises selecting all the nozzles for purging.
Claim 12
Dependent Claim
43 words
A method according to claim 1, further comprising the step of firing a number of purging ink droplets from each nozzle to ensure that each nozzle has been fired a selected number of times during printing for consecutive time intervals of selected duration.
Claim 13
Dependent Claim
33 words
A method according to claim 1, further including the steps of: monitoring a characteristic of each nozzle; and determining from the monitored characteristic which nozzles to select for firing in the purging step.
Claim 14
Dependent Claim
54 words
A method according to claim 12, wherein: the monitoring step comprises the step of monitoring the temperature of each nozzle; and the determining step comprises the step of comparing the monitored temperature of each nozzle with a threshold limit to select any nozzle for the purging step that has a temperature failing the threshold.
Claim 15
Dependent Claim
53 words
A method according to claim 12, wherein: the monitoring step comprises the step of monitoring the efficiency of each nozzle; and the determining step comprises the step of comparing the monitored efficiency of each nozzle with a threshold limit to select any nozzle having an efficiency failing the threshold for the purging step.
Claim 16
Dependent Claim
46 words
A method according to claim 1, wherein: the printed image includes at least one black printed area or a color printed area; and the purging step comprises locating the purging ink droplets in at least one of the black or color printed areas of the image.
Claim 17
Dependent Claim
23 words
A method according to claim 15, wherein the locating step comprises locating the purging ink droplets away from edges of any printed area.
Claim 18
Dependent Claim
22 words
A method according to claim 15, wherein the purging step comprises locating color ink droplets in the black areas of the image.
Claim 19
Dependent Claim
34 words
A method according to claim 1, wherein: the printing mechanism includes a spittoon portion; and the method further includes the step of spitting by firing selected nozzles to deposit ink droplets into the spittoon.
Claim 20
Dependent Claim
19 words
A method according to claim 1, wherein the purging step comprises locating purging ink droplets beside image ink droplets.
Claim 21
Dependent Claim
21 words
A method according to claim 1, wherein the purging step comprises locating purging ink droplets in a pattern on the page.
Claim 22
Dependent Claim
24 words
A method according to claim 1, wherein the purging step comprises locating purging ink droplets in a pattern that is repeated on the page.
Claim 23
Independent Claim
117 words
A method of purging an inkjet printhead used in an inkjet printing mechanism, comprising the steps of: firing selected nozzles of the printhead to deposit image ink droplets on a print media page to print a selected image; purging selected nozzles by firing to deposit purging ink droplets on the page; in consecutive passes, scanning the printhead through a print zone of the inkjet printing mechanism during the firing and purging steps; tracking the number of times each nozzle is fired during each pass; monitoring the timing of each pass; and determining from the tracking and monitoring steps of one pass which nozzles to fire in the purging step during the next pass following said one pass.
Claim 24
Independent Claim
117 words
A method of purging an inkjet printhead used in an inkjet printing mechanism, comprising the steps of: firing selected nozzles of the printhead to deposit image ink droplets on a print media page to print a selected image; purging selected nozzles by firing to deposit purging ink droplets on the page; in consecutive passes, scanning the printhead through a print zone of the inkjet printing mechanism during the firing and purging steps; tracking the number of times each nozzle is fired during each pass; monitoring the timing of each pass; and determining from the tracking and monitoring steps of one pass which nozzles to fire in the purging step during the next pass following said one pass.
Claim 25
Independent Claim
102 words
A method of purging an inkjet printhead used in an inkjet printing mechanism including a spittoon portion, comprising the steps of: firing selected nozzles of the printhead to deposit image ink droplets on a print media page to print a selected image; providing a selection of at least two different modes of print quality; identifying nozzles in need of purging; and purging the identified nozzles by firing to deposit purging ink droplets, and depositing the purging ink droplets on the page for a first print quality mode, and depositing the purging ink droplets in the spittoon for a second print quality mode.
Claim 26
Independent Claim
102 words
A method of purging an inkjet printhead used in an inkjet printing mechanism including a spittoon portion, comprising the steps of: firing selected nozzles of the printhead to deposit image ink droplets on a print media page to print a selected image; providing a selection of at least two different modes of print quality; identifying nozzles in need of purging; and purging the identified nozzles by firing to deposit purging ink droplets, and depositing the purging ink droplets on the page for a first print quality mode, and depositing the purging ink droplets in the spittoon for a second print quality mode.
Claim 27
Dependent Claim
69 words
A method according to claim 23, wherein: the inkjet printing mechanism comprises an inkjet printhead that makes multiple passes across a print zone to print the image in a multipass shingled print mode; and while printing in the first print quality mode, the purging step further comprises the step of depositing the purging ink droplets under or on top of image ink droplets in a multipass shingled print mode.
Claim 28
Dependent Claim
32 words
A method according to claim 23, wherein the purging step comprises depositing the purging ink droplets on the page by blending the purging ink droplets into a background portion of the page.
Claim 29
Dependent Claim
25 words
A method according to claim 23, wherein the identifying step comprises the step of counting the number of image ink droplets fired from each nozzle.
Claim 30
Dependent Claim
34 words
A method according to claim 23, wherein the identifying step comprises the steps of: monitoring a characteristic of each nozzle; and determining from the monitored characteristic whether the nozzle is in need of purging.
Claim 31
Dependent Claim
51 words
A method according to claim 27, wherein: the monitoring step comprises the step monitoring the temperature of each nozzle; and the determining step comprises comparing the monitored temperature of each nozzle with a threshold limit to identify any nozzle having a temperature failing the limit as being in need of purging.
Claim 32
Dependent Claim
51 words
A method according to claim 27, wherein: the monitoring step comprises the step monitoring the efficiency of each nozzle; and the determining step comprises comparing the monitored efficiency of each nozzle with a threshold limit to identify any nozzle having an efficiency failing the limit as being in need of purging.
Claim 33
Dependent Claim
96 words
An inkjet printing mechanism, comprising: a chassis; a printhead mounted to the chassis for movement across a print zone, the printhead having plural nozzles selectively fired to deposit image ink droplets on a print media page to print a selected image in response to a control signal; a spittoon portion; and a controller that generates the control signal to fire purging ink droplets from selected nozzles to deposit purging ink droplets on the page for a first print quality mode, and to deposit the purging ink droplets in the spittoon for a second print quality mode.
Claim 34
Dependent Claim
96 words
An inkjet printing mechanism, comprising: a chassis; a printhead mounted to the chassis for movement across a print zone, the printhead having plural nozzles selectively fired to deposit image ink droplets on a print media page to print a selected image in response to a control signal; a spittoon portion; and a controller that generates the control signal to fire purging ink droplets from selected nozzles to deposit purging ink droplets on the page for a first print quality mode, and to deposit the purging ink droplets in the spittoon for a second print quality mode.
Claim 35
Dependent Claim
25 words
An inkjet printing mechanism according to claim 30, wherein the controller generates the control signal in response to a signal received from a host device.
Claim 36
Dependent Claim
31 words
An inkjet printing mechanism according to claim 31, wherein the controller or the host device monitors the number of image ink droplets designated for each nozzle to generate the control signal.
Claim 37
Dependent Claim
45 words
An inkjet printing mechanism according to claim 30, wherein: the mechanism further includes for each nozzle, a monitor device that monitors a nozzle characteristic; and either the controller or the host device responds to the monitored characteristic of each nozzle to adjust the control signal.
Claim 38
Dependent Claim
42 words
An inkjet printing mechanism according to claim 33, wherein: the monitor device monitors the temperature of each nozzle; and the control signal is adjusted to, select nozzles from which purging ink droplets are fired when the monitored temperature fails a threshold limit.
Claim 39
Dependent Claim
42 words
An inkjet printing mechanism according to claim 33, wherein: the monitor device monitors the efficiency of each nozzle; and the control signal is adjusted to select nozzles from which purging ink droplets are fired when the monitored efficiency fails a threshold limit.
Claim 40
Dependent Claim
74 words
An inkjet printing mechanism according to claim 30, wherein: the inkjet printhead is mounted to the chassis for movement in multiple passes across the print zone to print the image in a multipass shingled print mode; and while printing in the first print quality mode, the controller generates the control signal to deposit purging ink droplets on the page either under or on top of image ink droplets in the multipass shingled print mode.
Claim 41
Dependent Claim
45 words
An inkjet printing mechanism according to claim 30 wherein, while printing in the first print quality mode, the controller generates the control signal to deposit the purging ink droplets on the page by blending the purging ink droplets into a background portion of the page.
References Cited (Backward Citations)
US4791435A
Cited
EP0316198A2
Cited
JPH01174459A
Cited
JPH023324A
Cited
EP0443832A1
Cited
EP0451827A2
Cited
US5177505A
Cited
JPH05338134A
Cited
US5369428A
Cited
JPH0615815A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-08-18 | 2001-02-17 | 2001-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-08-18 | 2005-02-17 | 2005-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-08-18 | 2009-02-17 | 2009-08-19 | $7700.00 | Window Closed / Lapsed |