TECHNICAL FIELD

The present disclosure relates to an image recording apparatus.

BACKGROUND

As an example of an image recording apparatus configured to record an image, JP-A-2004-58617 discloses an inkjet printer configured to discharge ink from a head, thereby recording an image. The inkjet printer of JP-A-2004-58617 is configured to alternately repeat a conveyance operation of moving a sheet (an example of a medium) in a conveyance direction and a printing operation of discharging ink to form dot rows while moving nozzles in a scanning direction, thereby printing an image on the sheet.

In the inkjet printer, when any image is printed by the two consecutive printing operations, diverse image quality degradations may be generated. JP-A-2004-58617 discloses a technology of suppressing banding, which is a kind of the image quality degradation. Specifically, when the adjacent dot rows are formed by the different printing operations, a mixed degree of the inks between the dot rows is different from a case where the adjacent dot rows are formed by the same printing operation, so that the banding may be generated. In JP-A-2004-58617, in order to suppress the banding, when forming the adjacent dot rows by the different printing operations, an amount of the ink to be discharged is regulated on the basis of information about a color of the image upon formation of at least one dot row.

As one kind of the image quality degradation, a step in an image has been known which is generated at a connecting region of images of the two consecutive printing operations. The step in the image is generated when a formation position of a dot row to be formed by one printing operation entirely deviates in the scanning direction elative to a formation position of a dot row to be formed by the other printing operation, at a connecting region of images of the two consecutive printing operations. For example, the deviation of the formation position of the dot row may be caused when a spaced distance between the head and the sheet is different at upstream and downstream sides with respect to the conveyance direction upon the printing operation.

As the image recording apparatus, a line-type image recording apparatus including a plurality of recording heads arranged in a direction intersecting with a conveyance direction of a medium has been also known (refer toFIG. 21A). In the line-type image recording apparatus, a step in an image may be generated when a formation position of a dot row to be formed by one recording head entirely deviates in the conveyance direction relative to a formation position of a dot row to be formed by the other recording head, in a connecting region of images of the two adjacent recording heads. However, JP-A-2004-58617 does not disclosure countermeasures against the step in the image.

SUMMARY

An object of the present disclosure is to provide an image recording apparatus enables to record an image where a step in the image is inconspicuous.

One illustrative aspect provides an image recording apparatus having:

a conveyer configured to convey a medium in a conveyance direction;

a carriage configured to reciprocally move in a scanning direction intersecting with the conveyance direction;

a recording head mounted to the carriage and including a discharge surface in which a plurality of nozzles are aligned in the conveyance direction;

a memory configured to store image data including a plurality of dot elements corresponding to a plurality of dots to be formed on a medium, a discharge amount of liquid discharged for forming a corresponding dot is set for each of the plurality of dot elements in the image data; and

a controller configured to alternately execute a recording operation in which while moving the carriage in the scanning direction, the recording head discharges liquid of the discharge amount set for the dot elements of the image data from the plurality of nozzles to form dots on the medium, and a conveyance operation in which the conveyer conveys the medium in the conveyance direction, to record an image on the medium,

in which in a case of recording the image, the controller causes the conveyer, in the conveyance operation, to convey a medium in the conveyance direction such that a first dot formation range where dots are to be formed in a preceding recording operation of two consecutive recording operations and a second dot formation range where dots are to be formed in a subsequent recording operation of the two consecutive recording operations do not overlap each other, and

in which in a case of recording a specific image over a boundary between the first dot formation range and the second dot formation range, the specific image consisting of a plurality of discharged dots corresponding to dot elements having the set discharge amounts greater than zero among the plurality of dot elements of the image data, and having widths for a plurality of dots in the conveyance direction and in the scanning direction, the controller:

sets, as a correction portion, an end portion in the scanning direction of a specific region including at least one of a first boundary region and a second boundary region in the specific image, the first boundary region being located in a first image region recorded within the first dot formation range, the first boundary region being adjacent to the second dot formation range and having a length shorter than a length of the first dot formation range in the conveyance direction, and the second boundary region being located in a second image region recorded within the second dot formation range, the second boundary region being adjacent to the first dot formation range and having a length shorter than a length of the second dot formation range in the conveyance direction; and

forms the dot placed at the correction portion by discharging liquid of a discharge amount smaller than the discharge amount set for the dot element corresponding to the dot from at least one of the plurality of nozzles.

According to the above configuration, the size of the dot placed at the end portion in the scanning direction of at least one of the first boundary region and the second boundary region becomes smaller than the size of the dot formed in the discharge amount set for the dot element corresponding to the dot. Thereby, even when the formation position of the dot formed by the preceding recording operation and the formation position of the dot formed by the subsequent recording operation entirely deviate in the scanning direction and a step is thus generated in the image, it is possible to reduce the size of the dot formed at a corner portion of the step. As a result, it is possible to record an image where a step in the image is inconspicuous.

Another illustrative aspect provides an image recording apparatus having:

a conveyer configured to convey a medium in a conveyance direction;

a recording head unit including a plurality of recording heads each of which includes a nozzle row having a plurality of nozzles aligned in an intersection direction intersecting with the conveyance direction, the plurality of recording heads being aligned in the intersection direction such that arrangement regions having the nozzles arranged in two recording heads being adjacent to each other in the intersection direction among the plurality of recording heads, do not overlap each other in the conveyance direction;

a memory configured to store image data including a plurality of dot elements corresponding to a plurality of dots formed on a medium, a discharge amount of liquid discharged for forming a corresponding dot is set for each of the plurality of dot elements in the image data; and

a controller configured to cause the conveyer to convey a medium in the conveyance direction and cause the recording head unit to discharge liquid of the discharge amount set for the dot elements of the image data from the plurality of nozzles to form dots on the medium, to record an image on the medium, and

in which in a case of recording a specific image over a boundary between a first dot formation range where dots are formed by one of the two adjacent recording heads and a second dot formation range where dots are formed by the other of the two adjacent recording heads, the specific image consisting of a plurality of discharged dots corresponding to dot elements having the set discharge amounts greater than zero among the plurality of dot elements of the image data, and the specific image having widths for a plurality of dots in the conveyance direction and in the scanning direction, the controller:

sets, as a correction portion, an end portion in the conveyance direction of a specific region including at least one of a first boundary region and a second boundary region in the specific image, the first boundary region being located in a first image region recorded within the first dot formation range, the first boundary region being adjacent to the second dot formation range and having a length shorter than a length of the first dot formation range in the intersection direction, and the second boundary region being located in a second image region recorded within the second dot formation range, the second boundary region being adjacent to the first dot formation range and having a length shorter than a length of the second dot formation range in the intersection direction; and

forms the dot placed at the correction portion by discharging liquid of a discharge amount different from the discharge amount set for the dot element corresponding to the dot from at least one of the plurality of nozzles.

According to the above configuration, the size of the dot placed at the end portion in the conveyance direction of at least one of the first boundary region and the second boundary region is different from the size of the dot formed in the discharge amount set for the dot element corresponding to the dot. Thereby, even when the formation position of the dot formed by one of the two recording heads adjacent to each other and the formation position of the dot formed by the other entirely deviate in the conveyance direction and a step is thus generated in the image, it is possible to reduce the size of the dot formed at a corner portion of the step. As a result, it is possible to record an image where a step in the image is inconspicuous.

According to the present disclosure, is possible to record an image where a step in the image is inconspicuous.

