US6832825B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Test pattern printing method, information processing apparatus, printing apparatus and density variation correction method
Assignee: Canon Inc
•
Filing: 2000-10-04
•
Granted: 2004-12-21
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Expires: 2020-10-04
Abstract
Abstract An apparatus and method capable of obtaining an output characteristic of the print unit and determining a correction value for an output density, without using an expensive scanner. To realize this, a nozzle array consisting of a plurality of nozzles provided in the print head is divided into a plurality of nozzle blocks [a] to [d] and each of patches is formed by using the nozzles of the same nozzle block allocated to the patch. The patches are printed in a size and shape that allows the densities of the patches to be optically detected by the density sensor. A test pattern comprising these patches is measured by the density sensor to make a density correction for each nozzle of the print head.
Inventors
- 👤 Hitoshi Nishikori
- 👤 Naoji Otsuka
- 👤 Hitoshi Sugimoto
- 👤 Kiichiro Takahashi
- 👤 Osamu Iwasaki
- 👤 Kaneji Yamada
- 👤 Minoru Teshigawara
- 👤 Takeshi Yazawa
- 👤 Toshiyuki Chikuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 10:32
CPC Classifications
B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/21; B41J2/2121; B41J2/2128
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
166 words
A printing apparatus for performing a printing operation with a print head having a plurality of print elements, comprising: an optical sensor having a light emitting portion and a light receiving portion; pattern forming means for printing on a print medium a plurality of predetermined patterns conforming to a light emitting wavelength range of said optical sensor, each of the plurality of patterns being formed by each corresponding print element or each corresponding block made up of a plurality of print elements; measuring means for emitting light from the light emitting portion of said optical sensor against the patterns printed on the print medium by said pattern forming means and measuring optical characteristics of the plurality of patterns; and correction means for taking, as a reference density, a predetermined density obtained from the optical characteristics of each of the plurality of patterns, and calculating a ratio of a density of the patterns to the reference density to perform a correction process based upon the calculated ratio.
Claim 2
Dependent Claim
166 words
A printing apparatus for performing a printing operation with a print head having a plurality of print elements, comprising: an optical sensor having a light emitting portion and a light receiving portion; pattern forming means for printing on a print medium a plurality of predetermined patterns conforming to a light emitting wavelength range of said optical sensor, each of the plurality of patterns being formed by each corresponding print element or each corresponding block made up of a plurality of print elements; measuring means for emitting light from the light emitting portion of said optical sensor against the patterns printed on the print medium by said pattern forming means and measuring optical characteristics of the plurality of patterns; and correction means for taking, as a reference density, a predetermined density obtained from the optical characteristics of each of the plurality of patterns, and calculating a ratio of a density of the patterns to the reference density to perform a correction process based upon the calculated ratio.
Claim 3
Dependent Claim
89 words
A printing apparatus according to claim 1 , wherein said correction means has: a plurality of output density correction tables used to correct, according to a density value of print data, an output density value of the print data to be printed by the corresponding print element or by the corresponding block made up of a plurality of print data; and output density correction table selection means for selecting from among the output density correction tables according to the optical characteristic of each pattern read by said optical sensor.
Claim 4
Dependent Claim
79 words
A printing apparatus according to claim 2 , wherein said correction means further includes calculation means for detecting the lowest density from the optical characteristics of the measured patterns, taking the lowest density as a reference density and calculating a ratio of each pattern's density to the reference density, and said output density correction table selection means selects, based on the ratio calculated by said calculation means, an output density table for each block allocated to the corresponding pattern.
Claim 5
Dependent Claim
34 words
A printing apparatus according to claim 1 , further including a calibration means for calibrating the light emitting portion or light receiving portion of said optical sensor according to the tone of the pattern.
Claim 6
Dependent Claim
41 words
A printing apparatus according to claim 4 , wherein a drive signal supplied to a drive unit for driving the light emitting portion of said optical sensor can be modulated, and said calibration means performs calibration by modulating the drive signal.
Claim 7
Dependent Claim
21 words
A printing apparatus according to claim 1 , wherein the light emitting portion of said optical sensor is a white LED.
Claim 8
Dependent Claim
89 words
A printing apparatus according to claim 1 , wherein if the tone of a colorant forming the pattern has a wavelength that cannot be detected by said optical sensor, said pattern forming means forms a base with a colorant of a tone that can be detected by said optical sensor and then forms the pattern over the base with the colorant of the tone that cannot be detected by said optical sensor, and said measuring means measures the pattern of a secondary color formed by said pattern forming means.
Claim 9
Dependent Claim
26 words
A printing apparatus according to claim 1 , wherein said optical sensor has a plurality of light emitting portions and light receiving portions with different wavelengths.
Claim 10
Dependent Claim
28 words
A printing apparatus according to claim 8 , wherein the light emitting portions of said optical sensor are a green LED, a red LED and a blue LED.
Claim 11
Dependent Claim
20 words
A printing apparatus according to claim 1 , wherein the print elements perform printing according to an ink jet system.
Claim 12
Dependent Claim
34 words
A printing apparatus according to claim 10 , wherein said correction means adjusts the amount of ink ejected from the print elements according to a difference between the measured sensor output and the reference.
Claim 13
Dependent Claim
34 words
A printing apparatus according to claim 10 , wherein the print elements generate a bubble in the ink by using thermal energy and eject an ink droplet by a pressure of the generated bubble.
Claim 14
Dependent Claim
185 words
A density variation correction method using a printing apparatus, the printing apparatus performing a printing operation by using a print head having a plurality of print elements, the correction method comprising: a step of using an optical sensor having a light emitting portion and a light receiving portion; a pattern forming step for printing on a print medium a plurality of predetermined patterns conforming to a light emitting wavelength range of said optical sensor, each of the plurality of patterns being formed by each corresponding print element or each corresponding block made up of a plurality of print elements; a measuring step for emitting light from the light emitting portion of said optical sensor against the patterns printed on the print medium by the pattern forming step and measuring optical characteristics of the plurality of patterns; and a correction step for taking, as a reference density, a predetermined density obtained from the optical characteristics of each of the plurality of patterns, and calculating a ratio of a density of the patterns to the reference density to perform a correction process based upon the calculated ratio.
Claim 15
Dependent Claim
185 words
A density variation correction method using a printing apparatus, the printing apparatus performing a printing operation by using a print head having a plurality of print elements, the correction method comprising: a step of using an optical sensor having a light emitting portion and a light receiving portion; a pattern forming step for printing on a print medium a plurality of predetermined patterns conforming to a light emitting wavelength range of said optical sensor, each of the plurality of patterns being formed by each corresponding print element or each corresponding block made up of a plurality of print elements; a measuring step for emitting light from the light emitting portion of said optical sensor against the patterns printed on the print medium by the pattern forming step and measuring optical characteristics of the plurality of patterns; and a correction step for taking, as a reference density, a predetermined density obtained from the optical characteristics of each of the plurality of patterns, and calculating a ratio of a density of the patterns to the reference density to perform a correction process based upon the calculated ratio.
Claim 16
Dependent Claim
92 words
A density variation correction method according to claim 13 , wherein said correction step has: a plurality of output density correction tables used to correct, according to a density value of print data, an output density value of the print data to be printed by the corresponding print element or by the corresponding block made up of a plurality of print data; and an output density correction table selection step for selecting from among the output density correction tables according to the optical characteristic of each pattern read by said optical sensor.
Claim 17
Dependent Claim
82 words
A density variation correction method according to claim 14 , wherein said correction step further includes a calculation step for detecting the lowest density from the optical characteristics of the measured patterns, taking the lowest density as a reference density and calculating a ratio of each pattern's density to the reference density, and said output density correction table selection step selects, based on the ratio calculated by a calculation means, an output density table for each block allocated to the corresponding pattern.
Claim 18
Dependent Claim
36 words
A density variation correction method according to claim 13 , further including a calibration step for calibrating the light emitting portion or light receiving portion of said optical sensor according to the tone of the pattern.
Claim 19
Dependent Claim
43 words
A density variation correction method according to claim 16 , wherein a drive signal supplied to a drive unit for driving the light emitting portion of said optical sensor can be modulated, and the calibration step performs calibration by modulating the drive signal.
Claim 20
Dependent Claim
91 words
A density variation correction method according to claim 13 , wherein if the tone of a colorant forming the pattern has a wavelength that cannot be detected by said optical sensor, the pattern forming step forms a base with a colorant of a tone that can be detected by said optical sensor and then forms the pattern over the base with the colorant of the tone that cannot be detected by said optical sensor, and said measuring step measures the pattern of a secondary color formed by said pattern forming step.
Claim 21
Dependent Claim
164 words
A test pattern printing method for printing on a predetermined print medium a test pattern whose density is optically detected by a density sensor to obtain output characteristic information on a plurality of nozzles provided in a print unit mounted on said printing apparatus that reciprocates the print unit in a main scan direction and at the same time moves the print medium in a sub-scan direction crossing the main scan direction to perform printing on a predetermined area of the print medium, the test pattern printing method comprising the steps of: dividing a nozzle array made up of a plurality of nozzles provided in the print unit into a plurality of nozzle blocks; and printing each of patches in a size and shape that enables the density of the patch to be optically detected by said density sensor by using only the nozzles of the same nozzle block allocated to the patch being printed; wherein said test pattern comprises a plurality of patches.
Claim 22
Dependent Claim
164 words
A test pattern printing method for printing on a predetermined print medium a test pattern whose density is optically detected by a density sensor to obtain output characteristic information on a plurality of nozzles provided in a print unit mounted on said printing apparatus that reciprocates the print unit in a main scan direction and at the same time moves the print medium in a sub-scan direction crossing the main scan direction to perform printing on a predetermined area of the print medium, the test pattern printing method comprising the steps of: dividing a nozzle array made up of a plurality of nozzles provided in the print unit into a plurality of nozzle blocks; and printing each of patches in a size and shape that enables the density of the patch to be optically detected by said density sensor by using only the nozzles of the same nozzle block allocated to the patch being printed; wherein said test pattern comprises a plurality of patches.
Claim 23
Dependent Claim
50 words
A test pattern printing method according to claim 19 , wherein the test pattern comprises forward printing patches formed by the corresponding nozzle blocks during a forward movement of the print unit and backward printing patches formed by the corresponding nozzle blocks during a backward movement of the print unit.
Claim 24
Dependent Claim
33 words
A test pattern printing method according to claim 19 , wherein the test pattern comprises only forward printing patches formed by the corresponding nozzle blocks during a forward movement of the print unit.
Claim 25
Dependent Claim
23 words
A test pattern printing method according to claim 19 , wherein the plurality of nozzle blocks each have the same number of nozzles.
Claim 26
Dependent Claim
21 words
A test pattern printing method according to claim 19 , wherein the plurality of nozzle blocks have different numbers of nozzles.
Claim 27
Dependent Claim
37 words
A test pattern printing method according to claim 23 , wherein only those of the plurality of nozzle blocks which are situated at ends of the print unit have smaller numbers of nozzles than other nozzle blocks.
Claim 28
Dependent Claim
75 words
A test pattern printing method according to claim 19 , wherein the patches are formed by alternating a plurality of times a printing scan in the main scan direction with a movement of the print medium by a minimum width of the nozzle block, the single printing scan in the main scan direction being adapted to print a part of each of the plurality of patches on the print medium with the corresponding nozzle block.
Claim 29
Dependent Claim
165 words
An information processing apparatus for printing on a predetermined print medium a test pattern whose density is optically detected by a density sensor to obtain output characteristic information on a plurality of nozzles provided in a print unit mounted on a printing apparatus that reciprocates the print unit in a main scan direction and at the same time moves the print medium in a sub-scan direction crossing the main scan direction to perform printing on a predetermined area of the print medium, the information processing apparatus comprising: a means for dividing a nozzle array made up of a plurality of nozzles provided in the print unit into a plurality of nozzle blocks; and a means for printing each of patches in a size and shape that enables the density of the patch to be optically detected by said density sensor by using only the nozzles of the same nozzle block allocated to the patch being printed; wherein the test pattern comprises a plurality of patches.
Claim 30
Dependent Claim
165 words
An information processing apparatus for printing on a predetermined print medium a test pattern whose density is optically detected by a density sensor to obtain output characteristic information on a plurality of nozzles provided in a print unit mounted on a printing apparatus that reciprocates the print unit in a main scan direction and at the same time moves the print medium in a sub-scan direction crossing the main scan direction to perform printing on a predetermined area of the print medium, the information processing apparatus comprising: a means for dividing a nozzle array made up of a plurality of nozzles provided in the print unit into a plurality of nozzle blocks; and a means for printing each of patches in a size and shape that enables the density of the patch to be optically detected by said density sensor by using only the nozzles of the same nozzle block allocated to the patch being printed; wherein the test pattern comprises a plurality of patches.
Claim 31
Dependent Claim
49 words
An information processing apparatus according to claim 26 , wherein the test pattern comprises forward printing patches formed by the corresponding nozzle blocks during a forward movement of the print unit and backward printing patches formed by the corresponding nozzle blocks during a backward movement of the print unit.
Claim 32
Dependent Claim
32 words
An information processing apparatus according to claim 26 , wherein the test pattern comprises only forward printing patches formed by the corresponding nozzle blocks during a forward movement of the print unit.
Claim 33
Dependent Claim
22 words
An information processing apparatus according to claim 28 , wherein the plurality of nozzle blocks each have the same number of nozzles.
Claim 34
Dependent Claim
20 words
An information processing apparatus according to claim 28 , wherein the plurality of nozzle blocks have different numbers of nozzles.
Claim 35
Dependent Claim
36 words
An information processing apparatus according to claim 28 , wherein only those of the plurality of nozzle blocks which are situated at ends of the print unit have smaller numbers of nozzles than other nozzle blocks.
Claim 36
Dependent Claim
100 words
An information processing apparatus according to claim 26 , including: a density sensor for optically reading a density of each patch of the test pattern; an output density correction means having a plurality of output density correction tables, the output density correction tables being used to correct an output density value of print data according to a density value of the print data to be printed by the corresponding nozzle block; and an output density correction table selection means for selecting from among the output density correction tables according to the density of each patch read by said density sensor.
Claim 37
Dependent Claim
78 words
An information processing apparatus according to claim 32 , wherein the density correction means has a calculation means for taking as a reference density the lowest of the patch densities read by said density sensor and calculating a ratio of each patch's density to the reference density, and the output density correction table selection means selects, based on the ratio calculated by said calculation means, an output density table for each nozzle block allocated to the corresponding patch.
Claim 38
Dependent Claim
74 words
An information processing apparatus according to claim 26 , wherein the patches are formed by alternating a plurality of times a printing scan in the main scan direction with a movement of the print medium by a minimum width of the nozzle block, the single printing scan in the main scan direction being adapted to print a part of each of the plurality of patches on the print medium with the corresponding nozzle block.
Claim 39
Dependent Claim
147 words
A printing apparatus for printing on a predetermined print medium a test pattern whose density is optically detected by a density sensor to obtain output characteristic information on a plurality of nozzles provided in a print unit mounted on said printing apparatus that reciprocates the print unit in a main scan direction and at the same time moves the print medium in a sub-scan direction crossing the main scan direction to perform printing on a predetermined area of the print medium, said printing apparatus comprising: a means for dividing a nozzle array made up of a plurality of nozzles provided in the print unit into a plurality of nozzle blocks; and a means for printing each of patches on the print medium by using only the nozzles of the same nozzle block allocated to the patch being printed; wherein said test pattern comprises a plurality of patches.
Claim 40
Dependent Claim
147 words
A printing apparatus for printing on a predetermined print medium a test pattern whose density is optically detected by a density sensor to obtain output characteristic information on a plurality of nozzles provided in a print unit mounted on said printing apparatus that reciprocates the print unit in a main scan direction and at the same time moves the print medium in a sub-scan direction crossing the main scan direction to perform printing on a predetermined area of the print medium, said printing apparatus comprising: a means for dividing a nozzle array made up of a plurality of nozzles provided in the print unit into a plurality of nozzle blocks; and a means for printing each of patches on the print medium by using only the nozzles of the same nozzle block allocated to the patch being printed; wherein said test pattern comprises a plurality of patches.
Claim 41
Dependent Claim
48 words
A printing apparatus according to claim 35 , wherein said test pattern comprises forward printing patches formed by the corresponding nozzle blocks during a forward movement of the print unit and backward printing patches formed by the corresponding nozzle blocks during a backward movement of the print unit.
Claim 42
Dependent Claim
31 words
A printing apparatus according to claim 35 , wherein said test pattern comprises only forward printing patches formed by the corresponding nozzle blocks during a forward movement of the print unit.
Claim 43
Dependent Claim
21 words
A printing apparatus according to claim 35 , wherein the plurality of nozzle blocks each have the same number of nozzles.
Claim 44
Dependent Claim
19 words
A printing apparatus according to claim 35 , wherein the plurality of nozzle blocks have different numbers of nozzles.
Claim 45
Dependent Claim
35 words
A printing apparatus according to claim 39 , wherein only those of the plurality of nozzle blocks which are situated at ends of the print unit have smaller numbers of nozzles than other nozzle blocks.
Claim 46
Dependent Claim
73 words
A printing apparatus according to claim 35 , wherein the patches are formed by alternating a plurality of times a printing scan in the main scan direction with a movement of the print medium by a minimum width of the nozzle block, the single printing scan in the main scan direction being adapted to print a part of each of the plurality of patches on the print medium with the corresponding nozzle block.
Claim 47
Dependent Claim
33 words
A printing apparatus according to claim 35 , wherein the print unit applies a thermal energy to ink to generate a bubble and ejects the ink by an energy generated by the bubble.
References Cited (Backward Citations)
US4740796A
Cited
US4723129A
Cited
JPS5456847A
Cited
US4459600A
Cited
US4345262A
Cited
US4463359A
Cited
US4313124A
Cited
US4558333A
Cited
JPS5931949A
Cited
JPS59123670A
Cited
JPS59138461A
Cited
US4608577A
Cited
JPS6071260A
Cited
JPS6441375A
Cited
US5353052A
Cited
JPH0569545A
Cited
US5528270A
Cited
US6361139B1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-12-21 | 2008-06-21 | 2008-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-12-21 | 2012-06-21 | 2012-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-12-21 | 2016-06-21 | 2016-12-21 | $7700.00 | Window Closed / Lapsed |