US5946006A
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Method for correcting density unevenness for a recording head and an image formation apparatus provided with such a method
Assignee: Canon Inc
•
Filing: 1997-06-12
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Granted: 1999-08-31
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Expires: 2017-06-12
Abstract
Abstract An image formation apparatus provided according to the present invention does not generate any printing density streaks in low density areas of an image and is therefore capable of outputting stabilized images without any density unevennesses and density streaks in any tonality. The apparatus is structured so as to correct density signals in accordance with a correction table 1 for indicating the recording characteristics of each of the recording elements of the head and the recording characteristics indicated by this correction table 1, and to drive the recording head in accordance with a correction table 2, which does not allow the fore-going corrections to be made when the density signals are lower than a given density, and the density signals corrected by this correction table 2.
Inventors
- 👤 Hiroshi Tajika
- 👤 Masato Katayama
- 👤 Noribumi Koitabashi
- 👤 Miyuki Matsubara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:06
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/015; B41J2/04; B41J2/045; B41J2/04501; B41J2/04508; B41J2/04558; B41J2/0458; B41J2/21; B41J2/2132; B41J2/2139; B41J29/00; B41J29/38; B41J29/393; H; H04; H04N; H04N1/00; H04N1/40; H04N1/401; H04N1/4015
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
141 words
A method for correcting density unevenness for an image formation apparatus, the apparatus having a recording head with a plurality of recording elements arranged therein, each recording element having a recording characteristic, and driving means for driving the recording head, said method comprising the steps of: receiving image signals; generating correction signals to make corrections corresponding to each of the recording elements in accordance with data representing the recording characteristic of each of the recording elements of the recording head; correcting the image signals received in said receiving step with the correction signals; and driving the recording head with the driving means in accordance with the image signals corrected in said correction step to perform printing, wherein when the image signals indicate an image density lower than a predetermined density, a ratio of the corrections is reduced in said correction step.
Claim 2
Independent Claim
141 words
A method for correcting density unevenness for an image formation apparatus, the apparatus having a recording head with a plurality of recording elements arranged therein, each recording element having a recording characteristic, and driving means for driving the recording head, said method comprising the steps of: receiving image signals; generating correction signals to make corrections corresponding to each of the recording elements in accordance with data representing the recording characteristic of each of the recording elements of the recording head; correcting the image signals received in said receiving step with the correction signals; and driving the recording head with the driving means in accordance with the image signals corrected in said correction step to perform printing, wherein when the image signals indicate an image density lower than a predetermined density, a ratio of the corrections is reduced in said correction step.
Claim 3
Dependent Claim
29 words
A method for correcting density unevenness according to claim 1, wherein said correction step does not make the corrections when the image signals are lower than the predetermined density.
Claim 4
Dependent Claim
23 words
A method for correcting density unevenness according to claim 1, wherein the correction signals perform linear corrections in accordance with the image signals.
Claim 5
Dependent Claim
23 words
A method for correcting density unevenness according to claim 1, wherein the correction signals perform non-linear corrections in accordance with the image signals.
Claim 6
Dependent Claim
27 words
A method for correcting density unevenness according to claim 1, wherein the correction signals vary correction amounts in accordance with the densities indicated by the image signals.
Claim 7
Dependent Claim
31 words
A method according to claim 1, wherein the correction signals are generated in accordance with a correction table representing the recording elements and the correction signals corresponding to the recording elements.
Claim 8
Dependent Claim
23 words
A method according to claim 6, wherein the correction table is determined in accordance with results by forming and reading a test pattern.
Claim 9
Dependent Claim
26 words
A method according to claim 7, wherein the correction table is determined by density characteristics based on plural densities of a plurality of density test patterns.
Claim 10
Dependent Claim
31 words
A method according to claim 7, wherein the correction table is determined by density characteristics based on average density of recordings by each of the recording elements of the recording head.
Claim 11
Dependent Claim
31 words
A method according to claim 7, wherein the correction table is determined by density characteristics based on standard deviation of densities in each of the recording elements of the recording head.
Claim 12
Dependent Claim
24 words
A method according to claim 1, wherein a plurality of recording heads are provided and said correcting step is effected for each recording head.
Claim 13
Dependent Claim
35 words
A method according to claim 1, wherein the recording head comprises an ink jet recording head having a discharge port, and the recording head discharges ink through the discharge port by driving the recording elements.
Claim 14
Dependent Claim
28 words
A method according to claim 12, wherein each of the recording elements comprises means for generating thermal energy to be applied to the ink to discharge the ink.
Claim 15
Independent Claim
132 words
A method for correcting density unevenness for an image formation apparatus, the apparatus having a recording head with a plurality of recording elements arranged therein, each recording element having a recording characteristic, and driving means for driving the recording head, said method comprising the steps of: receiving image signals, the image signals being signals which represent density information of an image to be recorded; correcting the image signals corresponding to each recording element based on data representing a recording density characteristic of each of the recording elements of the recording head; and driving the recording head with the driving means in accordance with the image signal corrected in said correcting step, wherein said correcting step reduces a degree of correction of an image signal representing density information lower than a predetermined density.
Claim 16
Independent Claim
132 words
A method for correcting density unevenness for an image formation apparatus, the apparatus having a recording head with a plurality of recording elements arranged therein, each recording element having a recording characteristic, and driving means for driving the recording head, said method comprising the steps of: receiving image signals, the image signals being signals which represent density information of an image to be recorded; correcting the image signals corresponding to each recording element based on data representing a recording density characteristic of each of the recording elements of the recording head; and driving the recording head with the driving means in accordance with the image signal corrected in said correcting step, wherein said correcting step reduces a degree of correction of an image signal representing density information lower than a predetermined density.
Claim 17
Dependent Claim
49 words
A method according to claim 14, further comprising the step of image-processing to generate driving signals for driving the plurality of recording elements based on corrected image signals, wherein said driving step drives the recording elements of the recording head by the driving signals generated in said image-processing step.
Claim 18
Dependent Claim
29 words
A method according to claim 14, wherein said correcting step corrects an image signal based on a correction table representing a correction amount corresponding to the recording density characteristic.
Claim 19
Dependent Claim
23 words
A method according to claim 16, wherein the correction table is determined in accordance with results of forming and reading a test pattern.
Claim 20
Dependent Claim
26 words
A method according to claim 17, wherein the correction table is determined by density characteristics based on plural densities of a plurality of density test patterns.
Claim 21
Dependent Claim
31 words
A method according to claim 17, wherein the correction table is determined by density characteristics based on average density of recordings by each of the recording elements of the recording head.
Claim 22
Dependent Claim
31 words
A method according to claim 17, wherein the correction table is determined by density characteristics based on standard deviation of densities in each of the recording elements of the recording head.
Claim 23
Dependent Claim
24 words
A method according to claim 14, wherein a plurality of recording heads are provided and said correcting step is effected for each recording head.
Claim 24
Dependent Claim
35 words
A method according to claim 14, wherein the recording head comprises an ink jet recording head having a discharge port, and the recording head discharges ink through the discharge port by driving the recording elements.
Claim 25
Dependent Claim
28 words
A method according to claim 21, wherein each of the recording elements comprises means for generating thermal energy to be applied to the ink to discharge the ink.
Claim 26
Independent Claim
127 words
A method for correcting density unevenness for an image formation apparatus, the apparatus having a recording head with a plurality of recording elements arranged therein, each recording element having a recording characteristic, and driving means for driving the recording head, said method comprising the steps of: receiving image signals, the image signals being signals which represent density information of an image to be recorded; correcting the image signals corresponding to each recording element based on data representing a recording density characteristic of each of the recording elements of the recording head; and driving the recording head with the driving means in accordance with the image signals corrected in said correcting step, wherein said correcting step corrects an image signal representing density information higher than a predetermined density.
Claim 27
Independent Claim
127 words
A method for correcting density unevenness for an image formation apparatus, the apparatus having a recording head with a plurality of recording elements arranged therein, each recording element having a recording characteristic, and driving means for driving the recording head, said method comprising the steps of: receiving image signals, the image signals being signals which represent density information of an image to be recorded; correcting the image signals corresponding to each recording element based on data representing a recording density characteristic of each of the recording elements of the recording head; and driving the recording head with the driving means in accordance with the image signals corrected in said correcting step, wherein said correcting step corrects an image signal representing density information higher than a predetermined density.
Claim 28
Dependent Claim
49 words
A method according to claim 24, further comprising the step of image-processing to generate driving signals for driving the plurality of recording elements based on corrected image signals, wherein said driving step drives the recording elements of the recording head by the driving signals generated in said image-processing step.
Claim 29
Dependent Claim
29 words
A method according to claim 24, wherein said correcting step corrects an image signal based on a correction table representing a correction amount corresponding to the recording density characteristic.
Claim 30
Dependent Claim
23 words
A method according to claim 26, wherein the correction table is determined in accordance with results of forming and reading a test pattern.
Claim 31
Dependent Claim
26 words
A method according to claim 27, wherein the correction table is determined by density characteristics based on plural densities of a plurality of density test patterns.
Claim 32
Dependent Claim
31 words
A method according to claim 27, wherein the correction table is determined by density characteristics based on average density of recordings by each of the recording elements of the recording head.
Claim 33
Dependent Claim
31 words
A method according to claim 27, wherein the correction table is determined by density characteristics based on standard deviation of densities in each of the recording elements of the recording head.
Claim 34
Dependent Claim
24 words
A method according to claim 24, wherein a plurality of recording heads are provided and said correcting step is effected for each recording head.
Claim 35
Dependent Claim
34 words
A method according to claim 24, wherein the recording-head comprises an ink jet recording head having a discharge port, and the recording head discharges ink through the discharge port by driving the recording elements.
Claim 36
Dependent Claim
28 words
A method according to claim 31, wherein each of the recording elements comprises means for generating thermal energy to be applied to the ink to discharge the ink.
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2002-08-30 | 2003-03-01 | 2003-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-30 | 2007-03-01 | 2007-08-31 | $3760.00 | Window Closed / Lapsed |
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