Recorders – Combined with autographic apparatus
Reexamination Certificate
2002-01-29
2004-03-02
Do, An H (Department: 2853)
Recorders
Combined with autographic apparatus
C347S019000
Reexamination Certificate
active
06700593
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a technique for printing images by forming dots on a print medium during main scanning, and more particularly to a technique for determining an adjustment value for correcting the recording misalignment of dots in the direction of main scanning.
2. Description of the Related Art
Colorprinters having a head for ejecting several color inks are currently used on a wide scale as the output devices for computers. Some color printers print images by ejecting ink drops from nozzles to form dots on a print medium during main scanning.
In a printing operation in which ink drops are ejected from nozzles to form dots on the print medium, the recording positions of the dots sometimes become misaligned due to the backlash of the drive mechanism in the direction of main scanning, the warping of the platen that supports the print medium from below, and the like. The method disclosed in JP 5-69625A, filed by the present applicant, is known as an example of a technique aimed at preventing such misalignments. According to this conventional technique, adjustment values designed to cancel out the misalignment of dot formation in the direction of main scanning are registered in advance, and the recording positions in the forward and reverse passes are corrected based on these adjustment values.
Some color printers have a so-called bidirectional printing feature whereby ink drops are ejected both in the forward pass and reverse pass of main scanning in order to increase the printing speed. The aforementioned correction method can be used to prevent formed dots from being misaligned in the forward and reverse passes during such bidirectional printing. The aforementioned correction method can also be used to prevent formed dots from being misaligned among a plurality of nozzles during so-called unidirectional printing, in which ink drops are ejected only in either forward pass or reverse pass of main scanning.
With such conventional correction methods, however, it is difficult to provide optimal settings aimed at preventing printed images from acquiring graininess due to misaligned dot formation.
An object of the present invention, which was devised in order to overcome the above-described shortcomings of the prior art, is to achieve high efficiency in setting an adjustment value for adjusting a recording misalignment in the direction of main scanning when ink drops are ejected from nozzles to form dots on a print medium.
SUMMARY OF THE INVENTION
Aimed at partially addressing the above-described problems, the present invention entails setting adjustment values designed to reduce dot formation misalignments in the direction of main scanning during a printing process. In the printing process, a printing device equipped with a plurality of single-color nozzle groups for ejecting ink drops having mutually different colors is used. The printing device deposits the ink drops to form dots on a print medium while the plurality of single-color nozzle groups and/or the print medium is moved in a main scan. In the setting adjustment values, a first adjustment value is selected from a plurality of first possible adjustment values using a first misalignment verification pattern. A second adjustment value is selected from a plurality of second possible adjustment values using a second misalignment verification pattern, which is different from the first misalignment verification pattern. Adopting this approach makes it possible to set first and second adjustment values on the basis of actual print results. It is also possible to take into account different traits by setting adjustment values on the basis of different misalignment verification patterns.
It is preferable that the plurality of second possible adjustment values are set in a vicinity of the first adjustment value. Adopting this approach makes it possible to efficiently set a second adjustment value on the basis of a first adjustment value.
In setting of the second adjustment value, the second adjustment value may preferably be selected from the plurality of second possible adjustment values whose difference is less than the difference between the plurality of first possible adjustment values respectively. Adopting this approach makes it possible to set second adjustment values in smaller increments without analyzing a large volume of possible adjustment values.
In setting of the first adjustment value, the first misalignment verification pattern may preferably be formed on a print medium by one or more single-color nozzle groups, wherein the first misalignment verification pattern contains a plurality of first sub-patterns associated with the plurality of first possible adjustment values. The first adjustment value may preferably be set in accordance with correction information about a preferred corrected state selected from the first misalignment verification pattern. In setting of the second adjustment value, the second misalignment verification pattern may preferably be formed on a print medium by two or more of the single-color nozzle groups, wherein the second misalignment verification pattern contains a plurality of second sub-patterns associated with the plurality of second possible adjustment values respectively. The second adjustment value may preferably be set in accordance with correction information about a preferred corrected state selected from the second misalignment verification pattern. With this approach, a second adjustment value can be set on the basis of an evaluation involving two or more ink colors.
The following procedure should preferably be adopted when the first misalignment verification pattern is formed. First ruled lines each contained in the first sub-pattern and oriented in a direction that intersects the direction of main scanning may be printed. Second ruled lines each contained in the first sub-pattern, oriented in a direction that intersects the direction of main scanning and associated with the first ruled line may be printed. With this approach, an appropriate first adjustment value can be set based on the relation between the relative positions of the first and second ruled lines.
The following procedure should preferably be adopted when the adjustment value is a value designed to reduce a dot formation misalignment occurring in the direction of main scanning in the course of a printing process in which ink drops are deposited and dots are formed on a print medium while main scanning is performed in opposite directions. In the printing of the first ruled lines, the first ruled lines may be printed in a forward pass of the main scan. In the printing of the second ruled lines, the second ruled lines are printed in a reverse pass of the main scan. Adopting this approach allows an appropriate first adjustment value to be set based on the relation between the relative positions of first ruled lines which reflect the dot formation misalignment of a forward pass, and second ruled lines, which reflect the dot formation misalignment of a reverse pass. The first adjustment value such decided may reduce any dot formation misalignments occurring during bidirectional printing.
In the printing of first ruled lines, the first ruled lines may preferably be printed by a specific single-color nozzle group. In the printing of second ruled lines, the second ruled lines may preferably be printed by a single-color nozzle group that is different from the single-color nozzle group used in the printing of the first ruled lines. With this approach, it is possible to set an appropriate first adjustment value for reducing dot formation misalignments between pairs of different single-color nozzle groups.
In the printing of the second misalignment verification pattern, uniform color patches may preferably be formed as the second sub-patterns. With this approach, a second adjustment value capable of providing print results with higher picture quality can be selected in an efficient manner when the aim is to perform uniformly dense printing.
In the printing of
Do An H
Seiko Epson Corporation
Sughrue & Mion, PLLC
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