Image processing apparatus and method and non-transitory computer-readable storage medium storing a computer-executable program for causing a computer to perform the method, for outputting or generating a pulse-width modulated signal

An image processing method of outputting an image signal to an image forming device which uses an electrophotographic method, the image processing method comprising:

• using a processor to perform the steps of:
• generating directional data representing a pattern which indicates a growing direction of a dot on a scanning line and in which the growing direction changes every predetermined number of scanning lines;
• setting correction coefficients to be used to distribute image data of a pixel of interest to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in a sub-scanning direction;
• detecting an edge portion of an image represented by input image data;
• distributing the image data of the pixel of interest of the input image data to the pixel of interest and the adjacent pixel in accordance with the correction coefficients;
• adding the image data distributed from the adjacent pixel to image data of the pixel of interest on which the distribution is performed, and outputting the added image data as corrected image data of the pixel of interest;
• selecting the corrected image data of the pixel of interest and the generated directional data for an edge portion of the image, and selecting the image data of the pixel of interest and input directional data supplied together with the input image data for a non-edge portion of the image;
• generating an image signal pulse-width modulated using the image data of the pixel of interest and the directional data selected in the selecting step;
• and
• outputting the pulse-width modulated image signal to the image forming device.

A non-transitory computer readable medium storing a computer-executable program for causing a computer to perform an image processing method of outputting an image signal to an image forming device which uses an electrophotographic method, the image processing method comprising the steps of:

• generating directional data representing a pattern which indicates a growing direction of a dot on a scanning line and in which the growing direction changes every predetermined number of scanning lines;
• setting correction coefficients to be used to distribute image data of a pixel of interest to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in a sub-scanning direction;
• detecting an edge portion of an image represented by input image data;
• distributing the image data of the pixel of interest of the input image data to the pixel of interest and the adjacent pixel in accordance with the correction coefficients;
• adding the image data distributed from the adjacent pixel to image data of the pixel of interest on which the distribution is performed, and outputting the added image data as corrected image data of the pixel of interest;
• selecting the corrected image data of the pixel of interest and the generated directional data for an edge portion of the image, and selecting the image data of the pixel of interest and input directional data supplied together with the input image data for a non-edge portion of the image;
• generating an image signal pulse-width modulated using the image data of the pixel of interest and the directional data selected in the selecting step;
• and
• outputting the pulse-width modulated image signal to the image forming device.

An image processing apparatus for outputting an image signal to an image forming device which uses an electrophotographic method, the apparatus comprising:

• a detector configured to detect an edge of an image represented by input image data in a main scanning direction of the image forming device so as to detect a line contained in the input image data;
• a distributor configured to distribute a pixel value of a pixel of interest, which is in the edge detected by the detector, of the input image data to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in a sub-scanning direction of the image forming device so as to correct pixel values of the pixel of interest and the adjacent pixel;
• an acquisition unit configured to acquire a dot growing direction for each scanning line in the main scanning direction;
• and
• a generator configured to generate, for each pixel, an image signal pulse-width modulated from a pixel value corrected by the distributor or a pixel value of the input image data in accordance with the dot growing direction,
• wherein the dot growing direction in the scanning line corresponding to an upper end of the edge is different from the dot growing direction in the scanning line corresponding to a lower end of the edge.

An image processing apparatus for outputting an image signal to an image forming device which uses an electrophotographic method, the apparatus comprising:

• an acquisition unit configured to acquire a distribution ratio for each scanning line in a main scanning direction of the image forming device, wherein the distribution ratio is set to correct a positional deviation in a sub-scanning direction of an image to be formed by the image forming device;
• a distributor configured to distribute a pixel value of a pixel of interest of input image data to the pixel of interest and a pixel adjacent to the pixel of interest in the sub-scanning direction based on the distribution ratio;
• a setting unit configured to set a dot growing direction for each scanning line in the main scanning direction;
• and
• a generator configured to generate an image signal pulse-width modulated from image data obtained as a distribution result by the distributor in accordance with the dot growing direction,
• wherein a pixel PK−1 on a scanning line K−1, a pixel PK on a scanning line K, and a pixel PK+1 on a scanning line K+1 are located in the same position in the main scanning direction, and the growing direction of the pixel PK−1 is different from that of the pixel PK+1.

An image processing method of outputting an image signal to an image forming device which uses an electrophotographic method, the method comprising:

• using a processor to perform the steps of:
• detecting an edge of an image represented by input image data in a main scanning direction of the image forming device so as to detect a line contained in the input image data;
• distributing a pixel value of a pixel of interest, which is in the edge detected in the detecting step, of the input image data to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in a sub-scanning direction of the image forming device so as to correct pixel values of the pixel of interest and the adjacent pixel;
• acquiring a dot growing direction for each scanning line in the main scanning direction;
• and
• generating, for each pixel, an image signal pulse-width modulated from a pixel value corrected in the distributing step or a pixel value of the input image data in accordance with the dot growing direction,
• wherein the dot growing direction in the scanning line corresponding to an upper end of the edge is different from the dot growing direction in the scanning line corresponding to a lower end of the edge.

An image processing method of outputting an image signal to an image forming device which uses an electrophotographic method, the method comprising:

• using a processor to perform the steps of:
• acquiring a distribution ratio for each scanning line in a main scanning direction of the image forming device, wherein the distribution ratio is set to correct a positional deviation in a sub-scanning direction of the image forming device;
• distributing a pixel value of a pixel of interest of input image data to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in the sub-scanning direction based on the distribution ratio;
• setting a dot growing direction for each scanning line in the main scanning direction;
• and
• generating an image signal pulse-width modulated from image data obtained as a distribution result in the distributing step in accordance with the dot growing direction,
• wherein a pixel PK−1 on a scanning line K−1, a pixel PK on a scanning line K, and a pixel PK+1 on a scanning line K+1 are located in the same position in the main scanning direction, and the growing direction of the pixel PK−1 is different from that of the pixel PK+1.

A non-transitory computer readable medium storing a computer-executable program for causing a computer to perform an image processing method of outputting an image signal to an image forming device which uses an electrophotographic method, the method comprising the steps of:

• detecting an edge of an image represented by input image data in a main scanning direction of the image forming device so as to detect a line contained in the input image data;
• distributing a pixel value of a pixel of interest, which is in the edge detected in the detecting step, of the input image data to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in a sub-scanning direction of the image forming device so as to correct pixel values of the pixel of interest and the adjacent pixel;
• acquiring a dot growing direction for each scanning line in the main scanning direction;
• and
• generating, for each pixel, an image signal pulse-width modulated from a pixel value corrected in the distributing step or a pixel value of the input image data in accordance with the dot growing direction,
• wherein the dot growing direction in the scanning line corresponding to an upper end of the edge is different from the dot growing direction in the scanning line corresponding to a lower end of the edge.

A non-transitory computer readable medium storing a computer-executable program for causing a computer to perform an image processing method of outputting an image signal to an image forming device which uses an electrophotographic method, the method comprising the steps of:

• acquiring a distribution ratio for each scanning line in a main scanning direction of the image forming device, wherein the distribution ratio is set to correct positional deviation in a sub-scanning direction of the image forming device;
• distributing a pixel value of a pixel of interest of input image data to the pixel of interest and an adjacent pixel adjacent to the pixel of interest in the sub-scanning direction based on the distribution ratio;
• setting a dot growing direction for each scanning line in the main scanning direction;
• and
• generating an image signal pulse-width modulated from image data obtained as a distribution result in the distributing step in accordance with the dot growing direction,
• wherein a pixel PK, on a scanning line K−1, a pixel PK on a scanning line K, and a pixel PK+1 on a scanning line K+1 are located in the same position in the main scanning direction, and the growing direction of the pixel PK−1 is different from that of the pixel PK+1.