Printing with multiple pixels as unit of gradation reproduction

A printing method employing a print head having a plurality of nozzles ejecting a same given ink and a plurality of eject drive elements for causing droplets of ink to be ejected from the plurality of nozzles, for printing on a print medium while performing main scanning;

• the method comprising the step of performing gradation reproduction with the same ink by:
• (i) designating as a unit of gradation reproduction a group of N contiguous pixels arranged in a selected one of a main scan direction and a sub scan direction where N is an integer of at least 2;
• (ii) setting a volume of ink ejectable onto at least one pixel location of the N pixels to a value different from a volume of ink ejectable onto other pixel locations;
• and
• (iii) controlling the volume of ink at each pixel location of the N pixels to reproduce M gradation levels for each group of the N pixels where M is an integer of at least N+2.

A print control device for supplying print data to a print device, the print device including a print head having a plurality of nozzles ejecting a same given ink and a plurality of eject drive elements for causing droplets of ink to be ejected from the plurality of nozzles, the print control device being capable of producing the print data for reproducing gradation levels with the same ink, the gradation reproduction being performed by:

• (i) designating as a unit of gradation reproduction a group of N contiguous pixels arranged in a selected one of a main scan direction and a sub scan direction where N is an integer of at least 2;
• (ii) setting a volume of ink ejectable onto at least one pixel location of the N pixels to a value different from a volume of ink ejectable onto other pixel locations;
• and
• (iii) controlling the volume of ink at each pixel location of the N pixels to reproduce M gradation levels for each group of the N pixels where M is an integer of at least N+2.

A print control method for supplying print data to a print device, the print device including a print head having a plurality of nozzles ejecting a same given ink and a plurality of eject drive elements for causing droplets of ink to be ejected from the plurality of nozzles, the print control method comprising the step of producing the print data for reproducing gradation levels with the same ink, the gradation reproduction being performed by:

• (i) designating as a unit of gradation reproduction a group of N contiguous pixels arranged in a selected one of a main scan direction and a sub scan direction where N is an integer of at least 2;
• (ii) setting a volume of ink ejectable onto at least one pixel location of the N pixels to a value different from a volume of ink ejectable onto other pixel locations;
• and
• (iii) controlling the volume of ink at each pixel location of the N pixels to reproduce M gradation levels for each group of the N pixels where M is an integer of at least N+2.

A computer program product for producing print data to be supplied to a print device, the print device including a print head having a plurality of nozzles ejecting a same given ink and a plurality of eject drive elements for causing droplets of ink to be ejected from the plurality of nozzles, the computer program product comprising:

• a computer readable medium;
• and
• a computer program stored on the computer readable medium, the computer program comprising:
• a program for causing a computer to produce the print data for reproducing gradation levels with the same ink, the gradation reproduction being performed by:
• (i) designating as a unit of gradation reproduction a group of N contiguous pixels arranged in a selected one of a main scan direction and a sub scan direction where N is an integer of at least 2;
• (ii) setting a volume of ink ejectable onto at least one pixel location of the N pixels to a value different from a volume of ink ejectable onto other pixel locations;
• and
• (iii) controlling the volume of ink at each pixel location of the N pixels to reproduce M gradation levels for each group of the N pixels where M is an integer of at least N+2.

A method of adjusting placement of ink droplets for a printing device including a print head having a plurality of nozzles ejecting a same given ink and a plurality of eject drive elements for causing droplets of ink to be ejected from the plurality of nozzles,

• wherein gradation reproduction with the same given ink is performed by:
• (i) designating as a unit of gradation reproduction a group of N contiguous pixels arranged in a selected one of a main scan direction and a sub scan direction where N is an integer of at least 2;
• (ii) setting a volume of ink ejectable onto at least one pixel location of the N pixels to a value different from a volume of ink ejectable onto other pixel locations;
• and
• (iii) controlling the volume of ink at each pixel location of the N pixels to reproduce M gradation levels for each group of the N pixels where M is an integer of at least N+2;
• wherein during printing the plurality of eject drive elements, in the course of one main scan, are driven so as to eject droplets of a predetermined volume of ink, predetermined for each main scan, exclusively at intermittent pixel locations selected from pixel locations on each main scan line scanned by the plurality of nozzles;
• and wherein the method comprises the steps of:
• (a) printing a first test pattern including two dot types of different size such that the two dot types are recorded substantially arrayed in single columns in the sub scanning direction;
• (b) determining a relative correction value for placement in the main scanning direction for the two dot types with reference to the first test pattern;
• and
• (c) performing correction of relative position of the two dot types using the relative correction value during printing, while forming the two dot types at different pixel locations on a same main scan line.

A computer program product for adjusting placement of ink droplets for a computer system comprising a printing device, the printing device including a print head having a plurality of nozzles ejecting a same given ink and a plurality of eject drive elements for causing droplets of ink to be ejected from the plurality of nozzles, the computer program product comprising:

• a computer readable medium;
• and
• a computer program stored on the computer readable medium,
• wherein gradation reproduction with the same given ink is performed by:
• (i) designating as a unit of gradation reproduction a group of N contiguous pixels arranged in a selected one of a main scan direction and a sub scan direction where N is an integer of at least 2;
• (ii) setting a volume of ink ejectable onto at least one pixel location of the N pixels to a value different from a volume of ink ejectable onto other pixel locations;
• and
• (iii) controlling the volume of ink at each pixel location of the N pixels to reproduce M gradation levels for each group of the N pixels where M is an integer of at least N+2;
• wherein during printing the plurality of eject drive elements, in the course of one main scan, are driven so as to eject droplets of a predetermined volume of ink, predetermined for each main scan, exclusively at intermittent pixel locations selected from pixel locations on each main scan line scanned by the plurality of nozzles;
• and wherein the computer program comprises:
• a first program for causing a computer to print out a first test pattern including two dot types of different size such that the two dot types are recorded substantially arrayed in single columns in the sub scanning direction;
• and
• a second program for causing the computer to perform correction of relative position of the two dot types using a relative correction value during printing where the relative correction value is determined with reference to the first test pattern, while forming the two dot types at different pixel locations on a same main scan line.

A print control device for controlling a printing device comprising a print head having a plurality of nozzles capable of performing high-resolution printing by ejecting ink drops onto each high-resolution pixel,

• wherein the print control device has a high-speed print mode and a low-speed print mode, and
• wherein when the high-speed print mode is selected, the print control device performs:
• resolution reduction to generate low-resolution image data from high-resolution image data, the high-resolution image data having a pixel value at each high-resolution pixel, the low-resolution image data having a pixel value at each low-resolution pixel consisting of a group of high-resolution pixels adjacent to each other;
• and
• printing of a low-resolution image by ejecting ink drops onto each high-resolution pixel according to the low-resolution image data.

A printing device comprising a print head having a plurality of nozzles capable of performing high-resolution printing by ejecting ink drops onto each high-resolution pixel,

• wherein the printing device has a high-speed print mode and a low-speed print mode, and
• wherein when the high-speed print mode is selected, the printing device performs:
• resolution reduction to generate low-resolution image data from high resolution image data, the high-resolution image data having a pixel value at each high-resolution pixel, the low-resolution image data having a pixel value at each low-resolution pixel consisting of a group of high-resolution pixels adjacent to each other;
• and
• printing of a low-resolution image by ejecting ink drops onto each high-resolution pixel according to the low-resolution image data.

A printing method using a print head having a plurality of nozzles capable of performing high-resolution printing by ejecting ink drops onto each high-resolution pixel, the method comprising:

• providing a high-speed print mode and a low-speed print mode, and
• when the high-speed print mode is selected,
• performing resolution reduction to generate low-resolution image data from high-resolution image data, the high-resolution image data having a pixel value at each high-resolution pixel, the low-resolution image data having a pixel value at each low-resolution pixel consisting of a group of high-resolution pixels adjacent to each other;
• and
• printing a low-resolution image by ejecting ink drops onto each high-resolution pixel according to the low-resolution image data.