Image recording apparatus

摘要

Nozzles for ejecting color ink are aligned in the conveying direction of a recording sheet at a pitch corresponding to three times the pitch of nozzles ejecting black ink. A region in which an image is printed is divided into sixteen regions segmented into four parts in the scanning and conveying directions. Each region includes eight dots in the scanning direction and four dots in the conveying direction. With respect to regions which include one character, in one side attachment regions, black ink is ejected only when an ink jet head is moved to the right side. With respect to regions which include one character, in the other side attachment regions, black ink is ejected only when the ink jet head is moved to the left side.

主权项

1. An image recording apparatus, comprising:
an ink jet head which includes a plurality of nozzles ejecting ink while moving in a main scanning direction; a conveyance section conveying a recording medium to which ink ejected from the plurality of nozzles is attached, in a sub-scanning direction perpendicular to the main scanning direction; and a control section controlling operation of the ink jet head and the conveyance section; wherein the plurality of nozzles include:
a plurality of first nozzles which are aligned at a first pitch P1 with respect to the sub-scanning direction; anda plurality of second nozzles which are aligned at a second pitch P2 (P2=nP1, n is an integer more than 1) with respect to the sub-scanning direction and eject ink of a type different from ink ejected from the plurality of the first nozzles;the aligned first and second nozzles being arranged in parallel with respect to the main scanning direction; wherein the control section performs control to alternately execute a one-side recording operation and an other-side recording operation for n times; wherein the control section performs control in the one-side recording operation to eject ink from the first nozzles while moving the ink jet head to one side in the main scanning direction; wherein the control section performs control in the other-side recording operation to eject ink from the second nozzles while moving the ink jet head to the other side in the main scanning direction; wherein the control section performs control to execute a conveying operation in which the recording medium is conveyed by a length equal to the first pitch P1 or by a length that is obtained by adding multiplication of the second pitch P2 by an integer to the first pitch P1 in the sub-scanning direction, every time any one of the one-side recording operation and the other-side recording operation is executed; wherein the control section performs control to repeatedly execute the conveying operation to repeatedly execute a unit recording operation for recording an image in a unit recording region of the recording medium extending in the main scanning direction, so as to record an image on the recording medium; wherein, in the one-side recording operation, ink is attached to a one-side attachment region which is a part of the unit recording region and in which a plurality of dots formed by the attached ink are aligned with respect to the main scanning direction; wherein, in the other-side recording operation, ink is attached to an other-side attachment region which is a part of the unit recording region and a part other than the one-side attachment region and in which a plurality of dots are aligned with respect to the main scanning direction; wherein the one-side attachment regions are determined so that an arbitrary one-side attachment region corresponding to an arbitrary unit recording operation and a second one-side attachment region corresponding to at least one unit recording operation among unit recording operations just before and after the arbitrary unit recording operation are in contact with each other with respect to the sub-scanning direction; and wherein the other-side attachment regions are determined so that an arbitrary other-side attachment region corresponding to the arbitrary unit recording operation and a second other-side attachment region corresponding to at least one unit recording operation among unit recording operations just before and after the arbitrary unit recording operation are in contact with each other with respect to the sub-scanning direction.