Liquid ejection apparatus

A liquid ejection apparatus, comprising:

• a head which has a plurality of ejection openings for ejecting liquid, the ejection openings being arranged at equal intervals relative to one direction,
• wherein the head includes a first head which ejects a first liquid, and a second head positioned upstream of the first head relative to a conveyance direction, which ejects a second liquid containing a component aggregated or precipitated by the first liquid;
• a conveyor which conveys a recording medium relatively to the head, in the conveyance direction intersecting the one direction;
• an image dot controller which controls the head based on image data so that the liquid is ejected from the ejection openings to form image dots structuring pixels of an image on the recording medium conveyed by the conveyor;
• a determiner which successively determines, for each of the ejection openings, whether an image dot non-forming period is equal to or longer than a predetermined time period, the image dot non-forming period being a period from a first time point where an image dot is formed to another time point where a subsequent image dot is formed under control by the image dot controller;
• a non-image ejection data generator which generates non-image ejection data for non-image dot formation,
• wherein the non-image ejection data generator is configured to set a non-image dot forming period for each ejection opening for which the determiner determined that the image dot non-forming period is equal to or longer than the predetermined time period, the non-image dot forming period being a period within which a single non-image dot is to be formed by the respective ejection opening, and the non-image dot forming period being a period from a third time point which is after the first time point to a second time point which is the predetermined time period after the first time point,
• wherein the non-image ejection data generator is configured to determine an ejection time within the non-image dot forming period for the respective ejection opening, the ejection time being a time at which the respective ejection opening is to form the single non-image dot,
• wherein the non-image ejection data generator is configured to determine whether the ejection time for a first ejection opening of the first head and the ejection time for a second ejection opening of the second head are such that the respective ejection times would cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening, the first ejection opening and the second ejection opening being aligned in the conveyance direction,
• wherein the non-image ejection data generator is configured to adjust one or more of the ejection time for the first ejection opening and the ejection time for the second ejection opening in response to determining that the respective ejection times would cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening such that, after adjusting the one or more of the ejection time for the first ejection opening and the ejection time for the second ejection opening, the respective ejection times would not cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening,
• wherein the non-image ejection data generator is configured to generate the non-image ejection data for each of the ejection openings, the non-image ejection data including the ejection time for the respective ejection opening as adjusted, and
• wherein the determiner successively determines, for each of the ejection openings, whether a non-ejection period is equal to or longer than another predetermined time period, the non-ejection period being a period from a fourth time point where the liquid is ejected from the ejection opening to another time point where subsequent ejection of the liquid from the ejection opening occurs under control by the image dot controller;
• and
• a non-image dot controller which controls the head so that each of the ejection openings, whose non-ejection period is equal to or longer than the other predetermined time period, ejects the liquid once within another time period ranging from the fourth time point to a fifth time point which is the other predetermined time period after the fourth time point, the other time period being in a beginning section subsequent to the fourth time point in the non-ejection period,
• wherein the non-image dot controller controls the head such that, for each ejection opening, a probability of ejecting liquid from the ejection opening is controlled to be a lesser value when a length of the period elapsed from the fourth time point is a first length than when the length of the period elapsed from the fourth time point is a second length greater than the first length, and
• wherein the non-image dot controller controls the head so that each of the ejection openings ejects, based on the non-image ejection data for the respective ejection opening, the liquid once within the non-image dot forming period in the image dot non-forming period for the respective ejection opening to form on the recording medium the non-image dot, which is not based on the image data, so that a plurality of the non-image dots structured by the liquid ejected from the ejection openings are scattered in the conveyance direction.

A liquid ejection apparatus, comprising:

• a head which has a plurality of ejection openings for ejecting liquid, the ejection openings being arranged at equal intervals relative to one direction,
• wherein the head includes a first head which ejects a first liquid, and a second head positioned upstream of the first head relative to a conveyance direction, which ejects a second liquid containing a component aggregated or precipitated by the first liquid;
• a conveyor which conveys a recording medium relatively to the head, in the conveyance direction intersecting the one direction;
• an image dot controller which controls the head based on image data so that the liquid is ejected from the ejection openings to form image dots structuring pixels of an image on the recording medium conveyed by the conveyor;
• a determiner which successively determines, for each of the ejection openings, whether an image dot non-forming period is equal to or longer than a predetermined time period, the image dot non-forming period being a period from a first time point where an image dot is formed to another time point where a subsequent image dot is formed under control by the image dot controller;
• a non-image ejection data generator which generates non-image ejection data for non-image dot formation,
• wherein the non-image ejection data generator is configured to set a non-image dot forming period for each ejection opening for which the determiner determined that the image dot non-forming period is equal to or longer than the predetermined time period, the non-image dot forming period being a period within which a single non-image dot is to be formed by the respective ejection opening, and the non-image dot forming period being a period from a third time point which is after the first time point to a second time point which is the predetermined time period after the first time point,
• wherein the non-image ejection data generator is configured to determine an ejection time within the non-image dot forming period for the respective ejection opening, the ejection time being a time at which the respective ejection opening is to form the single non-image dot,
• wherein the non-image ejection data generator is configured to determine whether the ejection time for a first ejection opening of the first head and the ejection time for a second ejection opening of the second head are such that the respective ejection times would cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening, the first ejection opening and the second ejection opening being aligned in the conveyance direction,
• wherein the non-image ejection data generator is configured to adjust one or more of the ejection time for the first ejection opening and the ejection time for the second ejection opening in response to determining that the respective ejection times would cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening such that, after adjusting the one or more of the ejection time for the first ejection opening and the ejection time for the second ejection opening, the respective ejection times would not cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening,
• wherein the non-image ejection data generator is configured to generate the non-image ejection data for each of the ejection openings, the non-image ejection data including the ejection time for the respective ejection opening as adjusted, and
• wherein the determiner successively determines, for each of the ejection openings, whether a non-ejection period is equal to or longer than another predetermined time period, the non-ejection period being a period from a fourth time point where the liquid is ejected from the ejection opening to another time point where subsequent ejection of the liquid from the ejection opening occurs under control by the image dot controller;
• and
• a non-image dot controller which controls the head so that each of the ejection openings, whose non-ejection period is equal to or longer than the other predetermined time period, ejects the liquid once within another time period ranging from the fourth time point to a fifth time point which is the other predetermined time period after the first time point, the other time period being in a beginning section subsequent to the fourth time point in the non-ejection period,
• wherein the non-image dot controller controls the head such that, for each ejection opening, an amount of liquid ejected from the ejection opening in the one ejection within the other time period ranging from the fourth time point to the fifth time point is positively correlated with a length of the period elapsed from the fourth time point, whereby the amount of liquid ejected from the ejection opening in the one ejection is a lesser amount when the length of the period elapsed from the fourth time point is a first length than when the length of the period elapsed from the fourth time point is a second length that is greater than the first length, and
• wherein the non-image dot controller controls the head so that each of the ejection openings ejects, based on the non-image ejection data for the respective ejection opening, the liquid once within the non-image dot forming period in the image dot non-forming period for the respective ejection opening to form on the recording medium the non-image dot, which is not based on the image data, so that a plurality of the non-image dots structured by the liquid ejected from the ejection openings are scattered in the conveyance direction.

A liquid ejection apparatus, comprising:

• a head which has a plurality of ejection openings for ejecting liquid, the ejection openings being arranged at equal intervals relative to one direction,
• wherein the head includes a first head which ejects a first liquid, and a second head positioned upstream of the first head relative to a conveyance direction, which ejects a second liquid containing a component aggregated or precipitated by the first liquid;
• a conveyor which conveys a recording medium relatively to the head, in the conveyance direction intersecting the one direction;
• an image dot controller which controls the head based on image data so that the liquid is ejected from the ejection openings to form image dots structuring pixels of an image on the recording medium conveyed by the conveyor;
• a non-image dot controller which controls the head so that the liquid is ejected from the ejection openings to form a non-image dot, which is not based on the image data, on the recording medium conveyed by the conveyor;
• and
• a determiner which successively determines, for each of the ejection openings, whether an image dot non-forming period is equal to or longer than a predetermined time period, the image dot non-forming period being a period from a first time point where an image dot is formed to another time point where a subsequent image dot is formed under control by the image dot controller;
• and
• a non-image ejection data generator which generates non-image ejection data for non-image dot formation,
• wherein the non-image ejection data generator is configured to set a non-image dot forming period for each ejection opening for which the determiner determined that the image dot non-forming period is equal to or longer than the predetermined time period, the non-image dot forming period being a period within which a single non-image dot is to be formed by the respective ejection opening, and the non-image dot forming period being a period from a third time point which is after the first time point to a second time point which is the predetermined time period after the first time point,
• wherein the non-image ejection data generator is configured to determine an ejection time within the non-image dot forming period for the respective ejection opening, the ejection time being a time at which the respective ejection opening is to form the single non-image dot,
• wherein the non-image ejection data generator is configured to determine whether the ejection time for a first ejection opening of the first head and the ejection time for a second ejection opening of the second head are such that the respective ejection times would cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening, the first ejection opening and the second ejection opening being aligned in the conveyance direction,
• wherein the non-image ejection data generator is configured to adjust one or more of the ejection time for the first ejection opening and the ejection time for the second ejection opening in response to determining that the respective ejection times would cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening such that, after adjusting the one or more of the ejection time for the first ejection opening and the ejection time for the second ejection opening, the respective ejection times would not cause the second ejection opening to eject the second liquid onto the single non-image dot formed by the first ejection opening,
• wherein the non-image ejection data generator is configured to generate the non-image ejection data for each of the ejection openings, the non-image ejection data including the ejection time for the respective ejection opening as adjusted, and
• wherein the non-image dot controller controls the head so that each of the ejection openings, whose image dot non-forming period is equal to or longer than the predetermined time period, ejects the liquid once within a non-image dot forming period in the image dot non-forming period to form on the recording medium the non-image dot, the non-image dot forming period being a period from a third time point which is after the first time point to a second time point which is the predetermined time period after the first time point, and so that a plurality of the non-image dots structured by the liquid ejected from the ejection openings are scattered in the conveyance direction.