Image data generating method, printing method, image data generating apparatus, and printer

An image data generating method of generating image data used in an inkjet printer, wherein

• said printer comprises a head for ejecting fine droplets of ink onto a printing medium and a scanning mechanism for moving said printing medium relatively to said head in a predetermined scan direction,
• said head has one or more outlet rows arranged in said scan direction, each of said one or more outlet rows includes a plurality of outlets arranged in a width direction perpendicular to said scan direction, and
• said image data generating method comprises the steps of:
• a) preparing a halftone image which represents ON/OFF of ejection of ink from said plurality of outlets in printing or a grayscale original image compared with a threshold matrix in generating a halftone image;
• and
• b) making sleep pixels representing sleep of ejection of ink, included in each pixel row which is a plurality of pixels arranged in a row direction corresponding to said width direction in said halftone image or said original image, to generate data of a final halftone image where while printing is performed, the number of outlets included in each outlet group which is brought into a sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows, and the number of outlets included in each outlet group which is not brought into said sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows.

A printing method using a head for ejecting fine droplets of ink onto a printing medium, wherein

• said head has one or more outlet rows arranged in a predetermined scan direction, each of said one or more outlet rows includes a plurality of outlets arranged in a width direction perpendicular to said scan direction,
• said printing method comprises the steps of:
• a) moving said printing medium relatively to said head in said scan direction;
• and
• b) performing ejection control of ink from said head while setting outlets of a sleep state in each of said one or more outlet rows, in parallel with said step a), and
• the number of outlets included in each outlet group which is brought into said sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows, and the number of outlets included in each outlet group which is not brought into said sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows, in said step b).

An image data generating apparatus for generating image data used in an inkjet printer, wherein

• said printer comprises a head for ejecting fine droplets of ink onto a printing medium and a scanning mechanism for moving said printing medium relatively to said head in a predetermined scan direction,
• said head has one or more outlet rows arranged in said scan direction, each of said one or more outlet rows includes a plurality of outlets arranged in a width direction perpendicular to said scan direction, and
• said image data generating apparatus comprises:
• a memory for storing a threshold matrix which is an array compared with a grayscale original image in generating a halftone image which represents ON/OFF of ejection of ink from said plurality of outlets in printing, said threshold matrix including sleep elements representing sleep of ejection of ink in each element row which is a plurality of elements arranged in a row direction corresponding to said width direction;
• and
• an image data generator for comparing said threshold matrix with said original image to generate data of a halftone image where while printing is performed, the number of outlets included in each outlet group which is brought into a sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows, and the number of outlets included in each outlet group which is not brought into said sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows.

An image data generating apparatus for generating image data used in an inkjet printer, wherein

• said printer comprises a head for ejecting fine droplets of ink onto a printing medium and a scanning mechanism for moving said printing medium relatively to said head in a predetermined scan direction,
• said head has one or more outlet rows arranged in said scan direction, each of said one or more outlet rows includes a plurality of outlets arranged in a width direction perpendicular to said scan direction, and
• said image data generating apparatus comprises:
• a memory for storing a halftone image which represents ON/OFF of ejection of ink from said plurality of outlets in printing or a grayscale original image compared with a threshold matrix in generating a halftone image;
• and
• an image data generator for making sleep pixels representing sleep of ejection of ink, included in each pixel row which is a plurality of pixels arranged in a row direction corresponding to said width direction in said halftone image or said original image, to generate data of a final halftone image where while printing is performed, the number of outlets included in each outlet group which is brought into a sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows, and the number of outlets included in each outlet group which is not brought into said sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows.

An inkjet printer, comprising:

• a head for ejecting fine droplets of ink onto a printing medium and having one or more outlet rows arranged in a predetermined scan direction, each of said one or more outlet rows including a plurality of outlets arranged in a width direction perpendicular to said scan direction;
• a scanning mechanism for moving said printing medium relatively to said head in said scan direction;
• and
• an ejection controller for performing ejection control of ink from said head while setting outlets of a sleep state in each of said one or more outlet rows, in parallel with relative movement of said printing medium to said head, wherein
• while printing is performed, the number of outlets included in each outlet group which is brought into a sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows, and the number of outlets included in each outlet group which is not brought into said sleep state continuously in said width direction is made to be equal to or larger than 1 and equal to or smaller than a predetermined number in each of said one or more outlet rows.