Printing system and image recording method
First Claim
1. A printing system having a head, from which inks are dischargeable to record at least two different dots having different characteristics on an object, and recording a multi-tone image by a distribution of said at least two different dots, said printing system comprising:
- input means for successively receiving a tone signal of each pixel included in an image to be printed;
recording ratio setting means for specifying recording ratios of said at least two different dots having different characteristics with respect to said each pixel, based on said input tone signal;
first dot formation determination means for comparing the recording ratio specified for a first dot among said at least two different dots having different characteristics with a threshold value corresponding to said each pixel and read from a threshold matrix, which corresponds to a dither pattern provided in advance, in order to determine whether or not said first dot is to be formed at a position corresponding to said each pixel;
second dot formation determination means for comparing the recording ratio specified for a second dot among said at least two different dots having different characteristics with the threshold value of said threshold matrix, in order to determine whether or not said second dot is to be formed at a position corresponding to said each pixel, except positions corresponding to the pixels where formation of said first dot has been determined; and
head driving means for driving said head to form said at least two different dots having different characteristics, based on the results of determination by said first dot formation determination means and said second dot formation determination means.
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Accused Products
Abstract
In a printer for printing an image by a distribution of dots having different densities per unit area or dots having different hues, the structure of the present invention accurately determines the on/off state of the different dots and ensuring high quality of printing. Recording ratios Rn and Rt of deep dots and light dots corresponding to input tone data DS in a target pixel are read from a map representing the relationship between the recording ratios and the tone data. The systematic dither method is adopted to determine formation or non-formation of a deep dot in the target pixel. This method compares the recording ratio Rn of deep dots with a threshold value Dref corresponding to the target pixel and read from a threshold matrix TM. In case that a deep dot is not formed, the recording ratio Rt of light dots is corrected by adding the recording ratio Rn of deep dots and subsequently compared with the same threshold value Dref to determine formation or non-formation of a light dot in the target pixel. The structure of the present invention uses only one threshold matrix to realize desired recording ratios without causing any over lap of deep dots with light dots. This structure is also applicable to dots having different hues. In this case, one threshold matrix is used to determine the on/off state of dots having different hues without causing any interference of the different hues.
40 Citations
24 Claims
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1. A printing system having a head, from which inks are dischargeable to record at least two different dots having different characteristics on an object, and recording a multi-tone image by a distribution of said at least two different dots, said printing system comprising:
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input means for successively receiving a tone signal of each pixel included in an image to be printed; recording ratio setting means for specifying recording ratios of said at least two different dots having different characteristics with respect to said each pixel, based on said input tone signal; first dot formation determination means for comparing the recording ratio specified for a first dot among said at least two different dots having different characteristics with a threshold value corresponding to said each pixel and read from a threshold matrix, which corresponds to a dither pattern provided in advance, in order to determine whether or not said first dot is to be formed at a position corresponding to said each pixel; second dot formation determination means for comparing the recording ratio specified for a second dot among said at least two different dots having different characteristics with the threshold value of said threshold matrix, in order to determine whether or not said second dot is to be formed at a position corresponding to said each pixel, except positions corresponding to the pixels where formation of said first dot has been determined; and head driving means for driving said head to form said at least two different dots having different characteristics, based on the results of determination by said first dot formation determination means and said second dot formation determination means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. An image recording method for recording a multi-tone image by a distribution of at least two different dots having different characteristics in a printing system with a head, from which inks are dischargeable to record said at least two different dots having different characteristics on an object, said method comprising the steps of:
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(a) successively receiving a tone signal of each pixel included in an image to be printed; (b) specifying recording ratios of said at least two different dots having different characteristics with respect to said each pixel, based on said input tone signal; (c) comparing the recording ratio specified for a first dot among said at least two different dots having different characteristics with a threshold value corresponding to said each pixel and read from a threshold matrix, which corresponds to a dither pattern provided in advance, in order to determine whether or not said first dot is to be formed at a position corresponding to said each pixel; (d) comparing the recording ratio specified for a second dot among said at least two different dots having different characteristics with the threshold value of said threshold matrix, in order to determine whether or not said second dot is to be formed at a position corresponding to said each pixel, except positions corresponding to the pixels where formation of said first dot has been determined; and (e) driving said head to form said at least two different dots having different characteristics, based on the results of determination in said step (c) and said step (d). - View Dependent Claims (23)
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24. Computer program product for driving a head of a printing system, from which inks are dischargeable to record at least two different dots having different characteristics on an object, said computer program product comprising:
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a computer readable medium; and computer program code means stored on said computer readable medium, said computer program code means storing at least part of a program for recording a multi-tone image by a distribution of said at least two different dots, said computer program code means comprising; first program code means for causing said computer to realize; second program code means for successively receiving a tone signal of each pixel included in an image to be printed; third program code means for specifying recording ratios of said at least two different dots having different characteristics with respect to said each pixel, based on said input tone signal; forth program code means for comparing the recording ratio specified for a first dot among said at least two different dots having different characteristics with a threshold value corresponding to said each pixel and read from a threshold matrix, which corresponds to a dither pattern provided in advance, in order to determine whether or not said first dot is to be formed at a position corresponding to said each pixel; and fifth program code means for comparing the recording ratio specified for a second dot among said at least two different dots having different characteristics with the threshold value of said threshold matrix, in order to determine whether or not said second dot is to be formed at a position corresponding to said each pixel, except positions corresponding to the pixels where formation of said first dot has been determined.
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Specification