Patent US6443548B1 successfully refreshed from Google Patents.
US6443548B1
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Printing apparatus and method for printing using a plurality of inks having different densities
Assignee: Canon Inc
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Filing: 1999-06-24
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Granted: 2002-09-03
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Expires: 2019-06-24
Abstract
Abstract A printing method and printing apparatus capable of printing a high-quality image representing excellent tonality even when a plurality of inks having the same color and different densities are adhered to the substantially same pixel position on a printing medium to form one print dot and represent tonality. When printing is to be performed on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, this apparatus calculates a lapse time from previous ink discharge, predicts a density change according to the lapse time based on the calculated lapse time, selects an ink and ink discharge amount suitable for representing a density value indicated by input multi-valued image data based on the predicted density change of ink, and drives the printhead so as to cause ink discharge from the printhead based on the selected ink and ink discharge amount.
Inventors
- 👤 Hidehito Takayama
- 👤 Kazumasa Matsumoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 14:56
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/40; H04N1/40087; B; B41; B41J; B41J2/00; B41J2/005; B41J2/01; B41J2/205; B41J2/2056
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
142 words
A printing method of performing printing on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, comprising: an input step, of inputting multi-valued image data; a calculation step, of calculating a lapse time from previous ink discharges by the printhead; a prediction step, of predicting a print density change according to a time variation of ink based on the lapse time calculated in said calculation step; a selection step, of selecting a type of ink and ink discharge amount suitable for representing a density value indicated by the input multi-valued image data based on the print density change predicted in said prediction step; and a driving step, of driving the printhead to cause ink discharge from the printhead based on the type of ink and ink discharge amount selected in said selection step.
Claim 2
Dependent Claim
142 words
A printing method of performing printing on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, comprising: an input step, of inputting multi-valued image data; a calculation step, of calculating a lapse time from previous ink discharges by the printhead; a prediction step, of predicting a print density change according to a time variation of ink based on the lapse time calculated in said calculation step; a selection step, of selecting a type of ink and ink discharge amount suitable for representing a density value indicated by the input multi-valued image data based on the print density change predicted in said prediction step; and a driving step, of driving the printhead to cause ink discharge from the printhead based on the type of ink and ink discharge amount selected in said selection step.
Claim 3
Dependent Claim
51 words
The method according to claim 1 , wherein said selection step includes: a step of selecting a type of ink to be discharged based on the multi-valued image data; and a step of changing a discharge amount of the selected type of ink in accordance with the predicted print density change.
Claim 4
Dependent Claim
35 words
The method according to claim 1 , wherein, in said driving step, droplets of a plurality of types of inks having different densities are discharged on the substantially same pixel position of the printing medium.
Claim 5
Dependent Claim
30 words
The method according to claim 1 , wherein said prediction step includes using a characteristic change table storing a relationship between the lapse time and the density change of ink.
Claim 6
Dependent Claim
24 words
The method according to claim 4 , wherein the characteristic change table is provided for each of a plurality of inks having different densities.
Claim 7
Dependent Claim
14 words
The method according to claim 4 , wherein the characteristic change table is rewritable.
Claim 8
Dependent Claim
24 words
The method according to claim 1 , wherein a plurality of printheads are used in correspondence with the plurality of inks having different densities.
Claim 9
Dependent Claim
27 words
The method according to claim 1 , wherein said selection step selects a type of ink and an ink discharge amount for each pixel subjected to printing.
Claim 10
Dependent Claim
21 words
The method according to claim 1 , wherein the plurality of inks having different densities are inks of the same color.
Claim 11
Dependent Claim
32 words
The method according to claim 1 , further comprising a pseudo half-tone step of performing pseudo half-tone processing in order to represent a density value indicated by the input multi-valued image data.
Claim 12
Dependent Claim
17 words
The method according to claim 10 , wherein the pseudo half-tone processing uses an error diffusion method.
Claim 13
Dependent Claim
141 words
A printing apparatus for performing printing on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, comprising: input means for inputting multi-valued image data; calculation means for calculating a lapse time from previous ink discharges by the printhead; prediction means for predicting a print density change according to a time variation of ink based on the lapse time calculated by said calculation means; selection means for selecting a type of ink and ink discharge amount suitable for representing a density value indicated by the multi-valued image data inputted by said input means, based on the print density change predicted by said prediction means; and driving means for driving the printhead to cause ink discharge from the printhead based on the type of ink and ink discharge amount selected by said selection means.
Claim 14
Dependent Claim
141 words
A printing apparatus for performing printing on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, comprising: input means for inputting multi-valued image data; calculation means for calculating a lapse time from previous ink discharges by the printhead; prediction means for predicting a print density change according to a time variation of ink based on the lapse time calculated by said calculation means; selection means for selecting a type of ink and ink discharge amount suitable for representing a density value indicated by the multi-valued image data inputted by said input means, based on the print density change predicted by said prediction means; and driving means for driving the printhead to cause ink discharge from the printhead based on the type of ink and ink discharge amount selected by said selection means.
Claim 15
Dependent Claim
53 words
The apparatus according to claim 12 , wherein said selection means includes: means for selecting a type of ink to be discharged based on the multi-valued image data; and means for changing a discharge amount of the selected type of ink in accordance with the print density change predicted by said prediction means.
Claim 16
Dependent Claim
33 words
The apparatus according to claim 12 , wherein said driving means discharges droplets of a plurality of types of inks having different densities to the substantially same pixel position of the printing medium.
Claim 17
Dependent Claim
33 words
The apparatus according to claim 12 , wherein said prediction means performs prediction by using a characteristic change table, which stores a relationship between the lapse time and the density change of ink.
Claim 18
Dependent Claim
24 words
The apparatus according to claim 12 , wherein a plurality of printheads are used in correspondence with the plurality of inks having different densities.
Claim 19
Dependent Claim
18 words
The apparatus according to claim 12 , wherein the printhead comprises a plurality of nozzles for discharging ink.
Claim 20
Dependent Claim
34 words
The apparatus according to claim 17 , wherein each of the plurality of nozzles of the printhead comprises an electrothermal transducer for generating heat energy in order to discharge ink by the heat energy.
Claim 21
Dependent Claim
33 words
The apparatus according to claim 17 , wherein each of the plurality of nozzles comprises a plurality of electrothermal transducers for changing an ink discharge amount from each of the plurality of nozzles.
Claim 22
Dependent Claim
27 words
The apparatus according to claim 12 , wherein said selection means selects a type of ink and an ink discharge amount for each pixel subjected to printing.
Claim 23
Dependent Claim
44 words
The apparatus according to claim 20 , wherein said selection means performs selection by referring to a table representing a relationship between a density value represented by the multi-valued image data, and a representable density value by a combination of inks having different densities.
Claim 24
Dependent Claim
21 words
The apparatus according to claim 12 , wherein the plurality of inks having different densities are inks of the same color.
Claim 25
Dependent Claim
40 words
The apparatus according to claim 12 , further comprising pseudo half-tone means for performing pseudo half-tone processing using an error diffusion method in order to represent a density value indicated by the multi-valued image data inputted by said input means.
Claim 26
Dependent Claim
160 words
A computer-readable memory which stores a program for executing printing processing of printing on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, the program comprising: codes for executing input processing of inputting multi-valued image data; codes for executing calculation processing of calculating a lapse time from previous ink discharges by the printhead; codes for executing prediction processing of predicting a print density change according to a time variation of ink based on the lapse time calculated in the calculation processing; codes for executing selection processing of selecting a type of ink and ink discharge amount suitable for representing a density value indicated by the input multi-valued image data based on the print density change predicted in prediction processing; and codes for executing driving processing of driving the printhead to cause ink discharge from the printhead based on the type of ink and ink discharge amount selected in the selection processing.
Claim 27
Dependent Claim
160 words
A computer-readable memory which stores a program for executing printing processing of printing on a printing medium by discharging ink from an inkjet printhead using a plurality of inks having different densities, the program comprising: codes for executing input processing of inputting multi-valued image data; codes for executing calculation processing of calculating a lapse time from previous ink discharges by the printhead; codes for executing prediction processing of predicting a print density change according to a time variation of ink based on the lapse time calculated in the calculation processing; codes for executing selection processing of selecting a type of ink and ink discharge amount suitable for representing a density value indicated by the input multi-valued image data based on the print density change predicted in prediction processing; and codes for executing driving processing of driving the printhead to cause ink discharge from the printhead based on the type of ink and ink discharge amount selected in the selection processing.
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| 3.5 Years (Year 4) | 2005-09-02 | 2006-03-04 | 2006-09-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2009-09-02 | 2010-03-04 | 2010-09-03 | $3760.00 | Window Closed / Lapsed |
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