Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2002-05-21
2003-12-02
Nguyen, Lamson (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S041000
Reexamination Certificate
active
06655783
ABSTRACT:
BACKGROUND 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 that is monochromatic only, 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 having a plurality of single chromatic nozzle groups and an achromatic nozzle group, a main scan drive unit that moves at least one of the printing head and the printing medium to perform main scanning, a sub-scan drive unit that 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, and a control unit that controls each of these units (the printing head, the main scan drive unit and the sub-scan drive unit). Each of the plurality of single chromatic nozzle groups consists of plurality of nozzles that are arranged at nozzle pitch k×D where k is an integer of at least 2 and D is a pitch of main scan lines. The plurality of single chromatic nozzle groups are configured to eject mutually different chromatic inks. The achromatic nozzle group for ejecting achromatic ink consists of a greater number of nozzles that are arranged at nozzle pitch k×D than each of the single chromatic nozzle groups.
It is preferable that the plurality of single chromatic nozzle groups each consists of mutually equal numbers of nozzles. It is also preferable that the specific achromatic nozzle group includes a same number of nozzles as each of the single chromatic nozzle groups.
In that apparatus, monochromatic mode printing is also executed by repeating a unit scan operation using all the nozzles of the achromatic nozzle group but without using the single chromatic nozzle groups. The unit scan operation consists of k main scans and (k−1) sub-scans of a first feed amount. The unit scan operation in the monochromatic mode printing may be performed such that all dot positions in an achromatic unit band consisting of plural main scan lines without any gap therebetween are serviced by the achromatic nozzle group. A monochromatic mode sub-scan of a second feed amount is performed in each interval between each unit scan operations.
In that apparatus, color mode printing is executed by repeating the unit scan operation using a specific achromatic nozzle group and the plurality of single chromatic nozzle groups while a color mode sub-scan of a third feed amount less than the second feed amount is performed in each interval between each unit scan operations. The specific achromatic nozzle group is part of the achromatic nozzle group.
In specific case in the monochromatic mode printing, specific process is executed. The case is when a lowermost main scan line of a second achromatic unit band comes to be positioned within the color area when it is assumed that a set of the color mode sub-scan and the unit scan operation is performed J times (where J is an integer of two or greater). The second achromatic unit band consists of plural main scan lines without any gap therebetween for which the specific achromatic nozzle group services with a single unit scan operation.
In above specific case, a sub-scan whose feed amount is equal to a sum of (J−1) times the third feed amount and (J−2) times a total feed amount of sub-scans performed in one unit scan operation is performed. The printing process proceeds to the color mode printing. Such an embodiment makes it possible to efficiently execute monochromatic printing when an attempt is made to transition to color mode printing.
It should be preferred that the printing process proceeds to the color mode printing, in a case that a lowermost main scan line of the first achromatic unit band comes to be positioned within the color area when it is assumed that the monochromatic mode sub-scan of the second feed amount and the unit scan operation are performed. Such an embodiment makes it possible, based on simple decision criteria, to execute the transition process from monochromatic mode printing to color mode printing.
The printing mode transitioning procedure may be as follows. The case the specific procedure to be performed may include three conditions all to be qualified. (i) A lowermost main scan line of the first achromatic unit band comes to be positioned within the color area when it is assumed that the monochromatic mode sub-scan and the unit scan operation are performed next. (ii) A lowermost main scan line of a second achromatic unit band comes to be positioned within the color area when it is assumed that a set of the color mode sub-scan and the unit scan operation is performed J times (where J is an integer of two or greater). (iii) A lowermost main scan line of the second achromatic unit band comes to be positioned within the monochromatic area when it is assumed that the set of the color mode sub-scan and the unit scan operation is performed (J−1) times. The second achromatic unit band consists of plural main scan lines without any gap therebetween for which the specific achromatic nozzle group services with a single unit scan operation.
If above conditions are all fulfilled, then a sub-scan whose feed amount is equal to a sum of (J−1) times the third feed amount and (J−2) times a total feed amount of sub-scans performed in one unit scan operation is performed; The unit scan operation is performed once, while forming dots in the monochromatic area using the achromatic nozzle group; The printing procedure proceeds to the color mode printing. Such an embodiment also makes it possible to efficiently execute monochromatic printing when an attempt is made to transition to color mode printing.
It is preferable that the printing procedure proceeds to the color mode printing in a case that a lowermost main scan line of the second achromatic unit band comes to be positioned within the color area when it is assumed that the color mode sub-scan and the unit scan operation are performed next. Such an embodiment makes it possible to efficiently transition from monochromatic mode printing to color mode printing when the distance from the lower tip of the print head to the color area and boundary is smaller than a prescribed value.
In a case that main scan line count Lr
1
of a remaining monochromatic a
Nguyen Lamson
Seiko Epson Corporation
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