Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2002-05-20
2003-10-07
Nguyen, Lamson (Department: 2861)
Incremental printing of symbolic information
Ink jet
Controller
C347S043000, C347S041000
Reexamination Certificate
active
06629744
ABSTRACT:
BACK GROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to technology for printing by forming dots on a printing medium while performing a main scan, and specifically relates to technology for printing images for which there are two types of areas, color areas and monochromatic areas, in the sub-scan direction.
2. Description of the Related Art
In recent years, as computer output devices, there has been a broad popularization of color printers of the type that eject several colors of ink from a head. Among this type of color printer, there are printers that print an image by forming dots on a printing medium by ejecting ink drops from a nozzle while performing a main scan.
Also, there are printing devices that are equipped with a higher number of nozzles that eject only black ink than those for other colored inks. For that kind of printing device, when printing color data, color printing is done using the same number of nozzles for each color. Only the same number of nozzles as the number of nozzles for each color is used for the black nozzles. Then, when printing data represent a monochromatic image, the monochromatic printing is performed at high speed using all of the black nozzles.
However, with the printing device noted above, when within the printed image there are two types of areas, monochromatic areas that use only black ink, and color areas, there is the problem that printing cannot be performed efficiently.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to efficiently print images for which two types of areas, color areas and monochromatic areas, exist in the sub-scan direction.
To attain at least part of the above and other related objects of the present invention, there is provided a printing apparatus that prints images in a monochromatic area on a printing medium with an achromatic ink alone, and in a color area with chromatic inks, by ejecting ink drops from a nozzle to deposit the ink drops on the printing medium to form dots.
This printing apparatus comprises a printing head, a main scan drive unit, a sub-scan drive unit and a control unit. The printing head has a plurality of single chromatic nozzle groups for ejecting mutually different chromatic inks and an achromatic nozzle group for ejecting achromatic ink. The plurality of single chromatic nozzle groups each consists of plurality of nozzles. The achromatic nozzle group consists of a greater number of nozzles than each of the single chromatic nozzle groups. The main scan drive unit moves at least one of the printing head and the printing medium to perform main scanning. The sub-scan drive unit moves at least one of the printing head and the printing medium in a direction that intersects a main scanning direction to perform sub-scanning. The control unit controls the printing head, the main scan drive unit and the sub-scan drive unit.
The printing device performs the following procedure when the lower edge of a monochromatic area and the upper edge of a color area come into contact with each other. Regular monochromatic mode printing is executed whereby sub-scans are performed in a first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area. Lower-edge monochromatic mode printing is executed whereby sub-scans are performed in a second sub-scan mode in which a maximum sub-scan feed increment is less than a maximum sub-scan feed increment of the first sub-scan mode, and dots are formed along the main scan lines in the monochromatic area in the vicinity of a border with the color area. Upper-edge color mode printing is executed whereby sub-scans are performed in a third sub-scan mode, and dots are formed along the main scan lines in the color area in the vicinity of the border with the monochromatic area. Regular color mode printing is executed whereby sub-scans are performed in a fourth sub-scan mode in which a maximum sub-scan feed increment is greater than a maximum sub-scan feed increment of the third sub-scan mode, and dots are formed along the main scan lines in the color area. Adopting this arrangement will result in a smooth transfer from the printing of a monochromatic area to the printing of a color area.
When the nozzles of the single chromatic nozzle groups are arranged at a nozzle pitch kc×D, and the nozzles of the achromatic nozzle group are arranged at a nozzle pitch km×D, the printing procedure may be preferably performed as follows. Specifically, the printing in each of the regular monochromatic mode printing, the lower-edge monochromatic mode printing, the upper-edge color mode printing and the regular color mode printing may be interlaced printing. Note that kc is an integer of 2 or greater, D is a pitch of main scan lines, and km is an integer of 2 or greater. Adopting this arrangement makes it possible to improve the quality of printed results.
The following approach should preferably be adopted when the single chromatic nozzle groups have mutually equal numbers of Nc nozzles (where Nc is an integer of 2 or greater) arranged at a nozzle pitch kc×D (where kc is an integer of 2 or greater), which is kc times the pitch D of the main scan lines, and the achromatic nozzle group has Nm nozzles (where Nm is an integer grate than Nc) arranged at a nozzle pitch km×D (where km is an integer equal to the inverse of the natural portion of kc).
In the regular monochromatic mode printing, monochromatic mode main scans may be preferably performed alternately with the sub-scans in which the achromatic nozzle group is used but the single chromatic nozzle groups are not used. In the lower-edge monochromatic mode printing, the monochromatic mode main scans may be preferably performed at least (km−1) times alternately with the sub-scans. In the upper-edge color mode printing, color mode main scans may be preferably performed at least (kc−1) times alternately with sub-scans in which the plurality of single chromatic nozzle groups and specific achromatic nozzle group are used. The specific achromatic nozzle group may be selected from the achromatic nozzle group and consist of Nc nozzles arranged at a nozzle pitch kc×D. In the regular color mode printing, color mode main scans may be performed alternately with the sub-scans. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines, and to transfer from the printing of monochromatic area to the printing of color area.
It is preferable that the plurality of single chromatic nozzle groups comprise a cyan nozzle group for ejecting a cyan ink, a magenta nozzle group for ejecting a magenta ink and a yellow nozzle group for ejecting a yellow ink. The cyan nozzle group, magenta nozzle group, and yellow nozzle group should preferably be disposed in the order indicated in the direction of sub-scanning. The achromatic nozzle group should preferably be equipped with Nc×3 nozzles arranged at a nozzle pitch kc×D and be disposed in the area for accommodating the nozzles cyan nozzle group, magenta nozzle group, and yellow nozzle group. The specific achromatic nozzle group should preferably be disposed in the area for accommodating the nozzles of the cyan nozzle group in the direction of sub-scanning. Adopting this arrangement makes it less likely that inks will bleed into each other, because the cyan, magenta, and yellow inks ejected within the same pixel are deposited onto this pixel during different main scans. It is also possible to arrange the nozzles of the achromatic nozzle groups in an optimal manner without unduly increasing the size of the print head in the direction of sub-scanning.
When the nozzles of the achromatic nozzle group are arranged at a nozzle pitch km×D, where km is an integer of 2 or greater, the sub-scans should preferably be performed (km−1) times in lower-edge monochromatic mode printing. Adopting this arrangement makes it possible to record images along each main scan line with no gaps between the lines in the monochromatic area in th
Nguyen Lamson
Seiko Epson Corporation
Sughrue & Mion, PLLC
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