Printing system and method for recording images using multivaluing techniques
First Claim
1. A printing system with a head, which forms at least two different dots having different densities per unit area on an object, for recording a multi-tone image by a distribution of the dots, said printing system comprising:
- input means for successively receiving a tone signal of each target pixel included in an image to be printed;
recording density setting means for specifying a recording density to be realized by at least a selected one of a dot having a higher density per unit area, that is, a higher-density dot, and a dot having a lower density per unit area, that is, a lower-density dot, which are both included in said at least two different dots having different densities, based on the input tone signal;
first dot formation determination means for carrying out a multivaluing operation based on the specified recording density, and determining whether or not the selected one of the higher-density dot and the lower-density dot is to be formed;
second dot formation determination means for making a result of the multivaluing operation by said first dot formation determination means reflect upon a recording density to be realized by the other one of the higher-density dot and the lower-density dot, causing the other one of the higher-density dot and the lower-density dot to be subjected to a multivaluing operation according to the reflected recording density, and determining whether or not the other one of the higher-density dot and the lower-density dot is to be formed; and
head driving means for driving the head based on results of the determination by said first dot formation determination means and said second dot formation determination means, in order to form said at least two different dots having different densities per unit area.
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Accused Products
Abstract
A system which enables a printer to print images with a plurality of dots having different densities per unit area to appropriately determine the on/off state of the plurality of dots and thereby improve the printing quality. The system of the present invention first refers to a table of a recording ratio with respect to a higher-density ink and determines whether or not deep dots are to be formed, based on input tone data, according to a systematic dither method. When it is determined that deep dots are formed, the system drives a piezoelectric element PE of an ink head corresponding to the higher-density ink to form deep dots and computes a resulting value RV of the deep dots. When it is determined that deep dots are not formed, the system sets the resulting value RV of the deep dots equal to zero, determines whether or not light dots are to be formed by a lower-density ink, based on the input tone data, according to an error diffusion technique, and computes a resulting value RV of the light dots. The on/off control of the light dots minimizes a density error or a difference of a resulting image from an original image. Another applicable structure makes the existence or non-existence of dots by an achromatic color ink reflect upon formation of dots by cyan ink.
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Citations
45 Claims
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1. A printing system with a head, which forms at least two different dots having different densities per unit area on an object, for recording a multi-tone image by a distribution of the dots, said printing system comprising:
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input means for successively receiving a tone signal of each target pixel included in an image to be printed; recording density setting means for specifying a recording density to be realized by at least a selected one of a dot having a higher density per unit area, that is, a higher-density dot, and a dot having a lower density per unit area, that is, a lower-density dot, which are both included in said at least two different dots having different densities, based on the input tone signal; first dot formation determination means for carrying out a multivaluing operation based on the specified recording density, and determining whether or not the selected one of the higher-density dot and the lower-density dot is to be formed; second dot formation determination means for making a result of the multivaluing operation by said first dot formation determination means reflect upon a recording density to be realized by the other one of the higher-density dot and the lower-density dot, causing the other one of the higher-density dot and the lower-density dot to be subjected to a multivaluing operation according to the reflected recording density, and determining whether or not the other one of the higher-density dot and the lower-density dot is to be formed; and head driving means for driving the head based on results of the determination by said first dot formation determination means and said second dot formation determination means, in order to form said at least two different dots having different densities per unit area. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A printing system with a head, which forms at least two different dots having different densities per unit area on an object, for recording a multi-tone image by a distribution of the dots, said printing system comprising:
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input means for successively receiving a tone signal of each target pixel included in an image to be printed; recording density setting means for specifying a first dot recording density, that is, a tone value to be realized by a first dot selected among said at least two different dots having different densities per unit area, based on the input tone signal; first dot formation determination means for determining whether or not the first dot is to be formed, based on the first dot recording density; correction signal computing means for computing a correction signal by adding quantization errors distributed from peripheral processed pixels in the vicinity of said target pixel to the input tone signal; second dot formation determination means for, when said first dot formation determination means determines no formation of the first dot, determining whether or not a second dot having a different density per unit area from that of the first dot is to be formed, based on the correction signal; head driving means for driving the head based on results of the determination by said first dot formation determination means and said second dot formation determination means, in order to form said at least two different dots having different densities per unit area; and error diffusion means for computing a quantization error, which is a difference between the correction signal and a tone value realized by the formed dots, as a density error, based on the results of the determination by said first dot formation determination means and said second dot formation determination means, and distributing and diffusing the computed density error to peripheral pixels in the vicinity of said target pixel. - View Dependent Claims (20, 21, 22, 23)
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24. A printing system with a head, which forms at least two different dots having different densities per unit area by a chromatic color ink as well as an achromatic dot by an achromatic color ink on an object, for recording a multi-tone image by a distribution of the dots, said printing system comprising:
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input means for successively receiving a tone signal of each target pixel included in an image to be printed; density specifying means for specifying a density to be realized by said chromatic color ink and a density to be realized by said achromatic color ink, based on the input tone signal; achromatic dot formation determination means for carrying out a multivaluing operation for said achromatic color ink, based on the density to be realized by said achromatic color ink, and determining whether or not the achromatic dot is to be formed by said achromatic color ink; density correcting means for obtaining correction data, which reflects upon the density to be realized by said chromatic color ink, based on the result of the multivaluing operation with respect to said achromatic color ink, in order to correct the density to be realized by said chromatic color ink; chromatic dot formation determination means for carrying out a multivaluing operation with respect to said at least two different dots having different densities per unit area, based on the corrected density to be realized by said chromatic color ink, and determining whether or not said at least two different dots are to be formed; and head driving means for driving the head based on results of the determination by said achromatic dot formation determination means and said chromatic dot formation determination means, in order to form said at least two different dots having different densities per unit area by said chromatic color ink and said achromatic dot by said achromatic color ink. - View Dependent Claims (25, 26, 27, 28, 29, 30)
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31. A printing system with a head, which forms at least two different dots having different densities per unit area on an object, for recording a multi-tone image by a distribution of the dots, said printing system comprising:
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input means for successively receiving a tone signal of each target pixel included in an image to be printed; first dot formation determination means for carrying out a multivaluing operation with respect to a selected dot among said at least two different dots having different densities per unit area, based on the input tone signal, and determining whether or not the selected dot is to be formed; difference computing means for computing a difference between the input tone signal and a printing density realized by the selected dot; second dot formation determination means for carrying out a multivaluing operation with respect to another dot among said at least two different dots having different densities, based on the difference, and determining whether or not the another dot is to be formed; and head driving means for driving the head based on results of the determination by said first dot formation determination means and said second dot formation determination means, in order to form said at least two different dots having different densities per unit area. - View Dependent Claims (32, 33, 34, 35, 36, 37, 38)
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39. A method of recording a multi-tone image by a distribution of at least two different dots having different densities per unit area, which are formed on an object by a head, said method comprising the steps of:
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successively receiving a tone signal of each target pixel included in an image to be printed; specifying a recording density to be realized by at least a selected one of a dot having a higher density per unit area, that is, a higher-density dot, and a dot having a lower density per unit area, that is, a lower-density dot, which are both included in said at least two different dots having different densities, based on the input tone signal; carrying out a multivaluing operation based on the specified recording density, and determining whether or not the selected one of the higher-density dot and the lower-density dot is to be formed; making a result of the multivaluing operation with respect to the selected dot reflect upon a recording density to be realized by the other one of the higher-density dot and the lower-density dot, causing the other one of the higher-density dot and the lower-density dot to be subjected to a multivaluing operation according to the reflected recording density, and determining whether or not the other one of the higher-density dot and the lower-density dot is to be formed; and driving the head based on results of the determination with respect to the selected dot and the other dot, in order to form said at least two different dots having different densities per unit area. - View Dependent Claims (40)
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41. A method of recording a multi-tone image by a distribution of at least two different dots having different densities per unit area, which are formed on an object by a head, said method comprising the steps of:
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successively receiving a tone signal of each target pixel included in an image to be printed; specifying a first dot tone value, that is, a tone value to be realized by a first dot selected among said at least two different dots having different densities per unit area, based on the input tone signal; determining whether or not the first dot is to be formed, based on the first dot tone value; computing a correction signal by adding quantization errors distributed from peripheral processed pixels in the vicinity of said target pixel to the input tone signal; when no formation of the first dot is determined according to the first dot tone value, determining whether or not a second dot having a different density per unit area from that of the first dot is to be formed, based on the correction signal; driving the head based on results of the determination with respect to the first dot and the second dot, in order to form said at least two different dots having different densities per unit area; and computing a quantization error, which is a difference between the correction signal and a tone value realized by the formed dots, as a density error, based on the results of the determination with respect to the first dot and the second dot, and distributing and diffusing the computed density error to peripheral pixels in the vicinity of said target pixel.
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42. A method of recording a multi-tone image by a distribution of at least two different dots having different densities per unit area as well as an achromatic dot, which are respectively formed on an object by a chromatic color ink and an achromatic color ink discharged from a head, said method comprising the steps of:
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successively receiving a tone signal of each target pixel included in an image to be printed; specifying a density to be realized by said chromatic color ink and a density to be realized by said achromatic color ink, based on the input tone signal; carrying out a multivaluing operation for said achromatic color ink, based on the density to be realized by said achromatic color ink, and determining whether or not the achromatic dot is to be formed by said achromatic color ink; obtaining correction data, which reflects upon the density to be realized by said chromatic color ink, based on the result of the multivaluing operation with respect to said achromatic color ink, in order to correct the density to be realized by said chromatic color ink; carrying out a multivaluing operation with respect to said at least two different dots having different densities per unit area, based on the corrected density to be realized by said chromatic color ink, and determining whether or not said at least two different dots are to be formed; and driving the head based on results of the determination with respect to said achromatic dot and said at least two different dots having different densities, in order to form said at least two different dots having different densities per unit area by said chromatic color ink and said achromatic dot by said achromatic color ink.
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43. A program product for controlling a head, which forms at least two different dots having different densities per unit area on an object, and recording a multi-tone image by a distribution of the dots, said program product comprising:
- a computer readable medium; and
computer program code means stored on said computer readable medium, said computer program code means comprising;first program code means for causing a computer to specify a recording density to be realized by at least a selected one of a dot having a higher density per unit area, that is, a higher-density dot, and a dot having a lower density per unit area, that is, a lower-density dot, which are both included in said at least two different dots having different densities, based on a tone signal successively input for each target pixel included in an image to be printed; second program code means for causing the computer to carry out a multivaluing operation based on the specified recording density, and to determine whether or not the selected one of the higher-density dot and the lower-density dot is to be formed; and third program code means for causing the computer to make a result of the multivaluing operation with respect to the selected dot reflect upon a recording density to be realized by the other one of the higher-density dot and the lower-density dot, to cause the other one of the higher-density dot and the lower-density dot to be subjected to a multivaluing operation according to the reflected recording density, and to determine whether or not the other one of the higher-density dot and the lower-density dot is to be formed.
- a computer readable medium; and
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44. A program product for controlling a head, which forms at least two different dots having different densities per unit area on an object, and recording a multi-tone image by a distribution of the dots, said program product comprising:
- a computer readable medium; and
computer program code means stored on said computer readable medium, said computer program code means comprising;first program code means for causing a computer to specify a first dot tone value, that is, a tone value to be realized by a first dot selected among said at least two different dots having different densities per unit area, based on a tone signal successively input for each target pixel included in an image to be printed; second program code means for causing the computer to determine whether or not the first dot is to be formed, based on the first dot tone value; third program code means for causing the computer to compute a correction signal by adding quantization errors distributed from peripheral processed pixels in the vicinity of said target pixel to the input tone signal; program code means for, when no formation of the first dot is determined according to the first dot tone value, causing the computer to determine whether or not a second dot having a different density per unit area from that of the first dot is to be formed, based on the correction signal; fourth program code means for causing the computer to drive the head based on results of the determination with respect to the first dot and the second dot, in order to form said at least two different dots having different densities per unit area; and fifth program code means for causing the computer to compute a quantization error, which is a difference between the correction signal and a tone value realized by the formed dots, as a density error, based on the results of the determination with respect to the first dot and the second dot, and to distribute and diffuse the computed density error to peripheral pixels in the vicinity of said target pixel.
- a computer readable medium; and
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45. A program product for controlling a head, which forms at least two different dots having different densities per unit area by a chromatic color ink as well as an achromatic dot by an achromatic color ink on an object, and recording a multi-tone image by a distribution of the dots, said program product comprising:
- a computer readable medium; and
computer program code means stored on said computer readable medium, said computer program code means comprising;first program code means for causing a computer to specify a density to be realized by said chromatic color ink and a density to be realized by said achromatic color ink, based on a tone signal successively input for each target pixel included in an image to be printed; second program code means for causing the computer to carry out a multivaluing operation for said achromatic color ink, based on the density to be realized by said achromatic color ink, and to determine whether or not the achromatic dot is to be formed by said achromatic color ink; third program code means for causing the computer to obtain correction data, which reflects upon the density to be realized by said chromatic color ink, based on the result of the multivaluing operation with respect to said achromatic color ink, in order to correct the density to be realized by said chromatic color ink; and fourth program code means for causing the computer to carry out a multivaluing operation with respect to said at least two different dots having different densities per unit area, based on the corrected density to be realized by said chromatic color ink, and to determine whether or not said at least two different dots are to be formed.
- a computer readable medium; and
Specification