Patent EP0674993A2 successfully refreshed from Google Patents.
EP0674993A2
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System, control circuit and method for electronic correction of pen misalignment in ink jet printers
Assignee: HP Inc
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Filing: 1995-03-28
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Granted: —
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Expires: 2015-03-28
Abstract
Abstract An ink-jet printing system includes a print head which, due to mechanical misalignment, produces images having a rotational ϑ-Z error if left uncorrected. The printing system has an error correction circuit which causes sets of nozzles within the print head to fire at slightly different times. The result of this is a printed image having one portion offset relative to another portion. The relative offset has the visual effect of reducing the ϑ-Z error. Several techniques for achieving the time spaced nozzle firing and resultant image offset are described. A method for correcting the ϑ-Z error in a printed image is also described.
Inventors
- 👤 Gary L. Miller
- 👤 Pirooz Emad
- 👤 Paul Dembiczak
- 👤 Richard I. Klaus
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:16
CPC Classifications
B; B41; B41J; B41J25/00; B41J25/001; B41J2/00; B41J2/005; B41J2/01; B41J2/015; B41J2/04; B41J2/045; B41J2/04501; B41J2/04505; B41J2/04541; B41J2/04543; B41J2/04573; B41J2/0458; B41J2/04581
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
186 words
An ink-jet printing system comprising: a print head (34) having an array of multiple nozzles (n1-n48) for depositing drops of ink onto a recording media during a swath to produce printed images; a print head controller (32) for commanding the print head (34) to fire individual nozzles to controllably deposit the ink drops according to a desired pattern, the desired pattern being defined by a stream of data; the printed images produced by the print head being different from the desired pattern by a rotational ϑ-Z error if the ink-jet printing system is left uncorrected; and error correction means for reducing the ϑ-Z error in the printed image by causing the print head to fire during the same swath (a) a first set of nozzles in the print head array to deposit first ink drops and (b) a second set of nozzles in the print head array to deposit second ink drops which are offset relative to the first ink drops on the recording media, the relative offset of the first and second ink drops being effective to reduce the ϑ-Z error in the printed image.
Claim 2
Dependent Claim
50 words
An ink-jet printing system according to claim 1 wherein the error correction means generates time spaced first and second fire signals for firing the first and second sets of nozzles, respectively, at different times to produce the relative offset of the first and second ink drops on the recording media.
Claim 3
Dependent Claim
103 words
An ink-jet printing system according to claim 1 wherein the error correction means comprises: a fire signal generator (58) to produce first and second fire signals at different times; and coupling circuitry (60) to connect the first fire signal to the first set of nozzles in the print head array and to connect the second fire signal to the second set of nozzles in the print head array, the first and second fire signals causing the first and second sets of nozzles to fire at different times to produce the relative offset of the first and second ink drops on the recording media.
Claim 4
Dependent Claim
140 words
An ink-jet printing system according to claim 1 wherein the print head controller has a fire signal generator (78) to create a fire signal for firing the nozzles (n1-n48) within the print head array; and the error correction means comprises: a delay circuit (82) coupled to the fire signal generator (78) to delay the fire signal by a time duration and thereby produce a delayed fire signal; and coupling circuitry (84) to connect the fire signal to the first set of nozzles in the print head array and to connect the delayed fire signal to the second set of nozzles in the print head array, the non-delayed and delayed fire signals causing the first and second sets of nozzles to fire at different times to produce the relative offset of the first and second ink drops on the recording media.
Claim 5
Dependent Claim
124 words
An ink-jet printing system according to claim 1 wherein the print head controller (92) has a fire signal generator (98) to create a fire signal for firing the nozzles (n1-n48) within the print head array; and the error correction means comprises: a switching circuit (102) coupled to the fire signal generator (98) to alternately distribute the fire signal to the first set of nozzles at a first time and to the second set of nozzles at a second time different than the first time, the time distributed fire signals output from the switching circuit (102) causing the first and second sets of nozzles to fire at different times to produce the relative offset of the first and second ink drops on the recording media.
Claim 6
Dependent Claim
107 words
An ink-jet printing system according to claim 1 wherein the error correction means comprises: logic circuitry (120) coupled between the print head controller (112) and the print head (114), the logic circuitry (120) receiving the data stream and selectively passing the data to the first set of nozzles in the print head at a different time than to the second set of nozzles, the logic circuitry (120) selectively passing the data to the first and second sets of nozzles in response to at least one enable signal; and a logic control circuit (128) coupled to the logic circuitry (120) to generate the at least one enable signal.
Claim 7
Dependent Claim
133 words
An ink-jet printing system according to claim 1 further comprising: a memory (152) for storing and outputting the stream of data, the data including first data for firing nozzles within the first set of nozzles and second data for firing nozzles within the second set of nozzles; and the error correction means being coupled to the memory (152) and manipulating the data output from the memory before the data is input into the print head (144), the error correction means shifting one of the first and second data relative to the other so that the print head fires the first set of nozzles at a first time and the second set of nozzles at a second time to produce the relative offset of the first and second ink drops on the recording medium.
Claim 8
Dependent Claim
128 words
An ink-jet printing system according to claim 1 further comprising: a memory (162) for receiving, storing and outputting the stream of data, the data including first data for firing nozzles within the first set of nozzles and second data for firing nozzles within the second set of nozzles; and the error correction means being coupled to the memory (162) and manipulating the data before the data is input to the memory, the error correction means shifting one of the first and second data relative to the other so that the print head fires the first set of nozzles at a first time and the second set of nozzles at a second time to produce the relative offset of the first and second ink drops on the recording medium.
Claim 9
Dependent Claim
126 words
An ink-jet printing system according to claim 1 wherein: the first set of nozzles comprises an upper portion of the print head nozzles and the second set of nozzles comprises a lower portion of the print head nozzles; and the error correction means is configured to (a) cause a rightward offset of the second ink drops deposited by the lower portion of nozzles relative to the first ink drops deposited by the upper portion of nozzles to reduce a ϑ-Z error in one rotational direction, and (b) cause a leftward offset of the second ink drops deposited by the lower portion of nozzles relative to the first ink drops deposited by the upper portion of nozzles to reduce a ϑ-Z error in an opposite rotational direction.
Claim 10
Dependent Claim
58 words
An ink-jet printing system according to claim 1 wherein the error correction means is configured to cause the print head to fire three or more sets of nozzles in the print head array to yield multiple groups of relatively offset ink drops on the recording media which are effective to reduce the ϑ-Z error in the printed image.
References Cited (Backward Citations)
No citation records indexed.
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