Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-11-12
2004-09-21
Nguyen, Lamson D (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S014000
Reexamination Certificate
active
06793321
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a print control apparatus, a print control method, and a medium storing a print control program. More particularly, the present invention relates to a print control apparatus to change the number of nozzles to be used, a print control method, and a medium storing a print control program.
2. Description of the Prior Art
A conventional method of color image printing involves scanning a print head having columnarly arranged nozzles to eject different color inks according to printing data. Printing in this manner produces image lines each consisting of pixels, and the number of nozzles corresponding to individual pixels is previously determined. If one nozzle is assigned to a certain color, each image line is printed with as many nozzles as color inks used. Likewise, if two nozzles are assigned to a certain color, each image line is printed with twice as many nozzles as color inks used. Increasing the number of nozzles constituting one line diminishes banding in full-overlap printing; however, this poses a problem with a decrease in printing speed.
SUMMARY OF THE INVENTION
The present invention was completed in view of the foregoing. It is an object of the present invention to provide a print control apparatus to change the number of nozzles to be used for each image line, a print control method, and a medium storing a print control program.
The invention to achieve the above-mentioned object is directed to a print control apparatus which causes a print head to print pixels constituting each image line during its primary scanning, said print head having columnarly arranged nozzles to eject different color inks according to printing data, said print control apparatus comprising an image line judging unit to judge whether or not a prescribed printing condition holds for the image line to be printed and a print control unit to change the number of nozzles to be used for printing each image line depending on whether or not said printing condition holds.
The print control apparatus according to the present invention causes a print head to print pixels constituting each image line during its primary scanning, said print head having columnarly arranged nozzles to eject different color inks according to printing data. While performing printing, the print control apparatus judges whether or not a prescribed printing condition holds for the image line to be printed. Then, the print control unit changes the number of nozzles (overlapping with each other) during the printing of each image line under the printing condition which has been established. In other words, each image line is printed such that the number of nozzles is changed depending on whether or not the printing condition has been established. The printing condition is not specifically restricted; it may be one which is based on the characteristic properties of the print pixels contained in each image line. Alternatively, it may be one which requires the number of nozzles to be changed in specific regions or which specifies specific pixel regions. The mode in which change is made is not specifically restricted; it may be 2-pattern (1 nozzle or 2 nozzles) or 3-pattern (1 nozzle, 2 nozzles, or 3 nozzles).
As explained above, the present invention makes it possible to change the number of nozzles adequately according to the printing condition for each image line at the time of printing.
The print control apparatus of the present invention may be constructed such that the print control unit (which changes the number of nozzles according to the printing condition) causes N nozzles to be used for the printing of an image line for which the printing condition is not established and also causes N+1 or more nozzles to be used for the printing of an image line for which the printing condition holds.
In this case, the print control unit causes N nozzles to be used for the printing of an image line for which the image line judging unit has judged that the printing condition does not hold. Also, the print control unit causes N+1 or more nozzles to be used for the printing of an image line for which the image line judging unit has judged that the printing condition holds. In this way it is possible to present one embodiment in which the number of nozzles is changed.
The printing condition is not specifically restricted as mentioned above. Therefore, it is possible to adopt an embodiment that permits the user to specify the printing condition to change the number of nozzles. In this case the user can conveniently change the number of nozzles at his discretion. Therefore, the print control apparatus of the present invention may be provided with a printing condition specifying unit which specifies the printing condition requiring a change to be made in the number of nozzles to be used for a specific image line.
In this case, the printing condition specifying unit can specify the printing condition (requiring a change to be made in the number of nozzles to be used) for a specific image line. Once the printing condition has been specified, the print control unit changes the number of nozzles to be used in the specific region which has been specified. In this way it is possible for the user to specify the image line for which the number of nozzles should be changed.
For the print control unit to judge whether or not the printing condition holds, the print control apparatus of the present invention may be constructed such that the image line judging unit judges whether or not the image line contains specific print pixels as the print condition.
In this case, the image line judging unit judges whether or not the image line contains specific print pixels as the print condition. In this way it is possible for the user to change the number of nozzles on the basis of print pixels.
Thus the print control apparatus of the present invention may be constructed such that the print control unit causes an image line to be printed with N+1 or more nozzles if the image line judging unit judges that the image line contains print pixels to be formed in a specific dot pattern.
In this case, the image line judging unit judges whether or not the image line contains print pixels to be formed in a specific dot pattern. If judge is so, the print control unit causes the image line to be printed with N+1 or more nozzles.
In this way it is possible to prevent banding by using more nozzles than usual for the printing of an image line which contains print pixels in a dot pattern which is subject to banding.
According to the present invention, the dot pattern in an image line to be printed with N+1 or more nozzles may be one which is formed with dots whose size is approximately equal to the resolution.
In this case, the image line judging unit judges that the print condition holds if an image line to be printed contains print dots formed with dots whose size is approximately equal to the resolution. Thus, the print control unit causes this image line to be printed with N+1 or more nozzles. In this way it is possible to show the dot pattern which is subject to banding.
Alternatively, the print control apparatus of the present invention may be constructed such that the print control unit causes an image line to be printed with N+1 or more nozzles if the image line judging unit judges that the image line contains print pixels to be formed with prescribed inks.
In this case, the image line judging unit judges whether or not the image line contains print pixels to be formed with prescribed inks. And, the print control unit causes the image line to be printed with N+1 or more nozzles if the image line judging unit judges that the image line contains such print pixels.
In this way it is possible to prevent banding by using more nozzles than usual for the printing of an image line which contains print pixels with ink colors which are subject to banding.
According to one embodiment of the present invention, the image line to be printed with N+1 or more nozz
Nguyen Lamson D
Sughrue & Mion, PLLC
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