Abstract: Threshold values in a dither matrix are arranged such that, in a case when screen processing is executed on a multi-tone image that has a first density, halftone dots are formed at a first screen angle, and, in a case when screen processing is executed on a multi-tone image that has a density being higher than a second density that is higher than the first density, halftone dots are formed at a second screen angle that is different from the first screen angle.

Abstract: An image forming apparatus in which a lighting position of a dot to be firstly generated by screen processing is changed, in a vertical direction, between a first sub-matrix and a second sub-matrix that are included in a dithering matrix and that are adjacent to each other in a lateral direction, in order not to generate a region where no dot exists in a main scanning direction.

Abstract: An image forming apparatus includes an image processing unit that executes, with respect to image data, image processing that adjusts an amount of a printing material to be applied to a printing medium, a calculation unit that calculates an amount of change of pixel values between a target pixel and a peripheral pixel that is adjacent to the target pixel, and a control unit that controls whether to execute the image processing for the target pixel based on the calculated amount of change of pixel values. In addition, a printing unit prints an image on the printing medium based on image data resulting from the control of execution of the image processing by the control unit.

Abstract: An image processing apparatus decides first growth points indicating positions at which dots for generating a screen having a low ruling are generated based on a predetermined screen ruling and screen angle, and second growth points that indicate positions at which dots for increasing the screen ruling of a screen represented by the first growth points are generated. The apparatus generates a screen for growing, in accordance with increase in pixel values of an input image, dots generated centered on the first growth points, and switching, when the pixel values exceed a threshold value, growth points from the first growth points to the second growth points, and growing, in accordance with increase in the pixel values, dots generated centered on the second growth points, and uses the generated screen for screen processing on image data to be printed.

Abstract: An image forming apparatus in which a lighting position of a dot to be firstly generated by screen processing is changed, in a vertical direction, between a first sub-matrix and a second sub-matrix that are included in a dithering matrix and that are adjacent to each other in a lateral direction, in order not to generate a region where no dot exists in a main scanning direction.

Abstract: Threshold values in a dither matrix according to the present invention are arranged such that in a case where screen processing is executed on a multi-tone image that has a first density, halftone dots are formed at a first screen angle, and in a case where screen processing is executed on a multi-tone image that has a density being higher than a second density that is higher than the first density, halftone dots are formed at a second screen angle that is different from the first screen angle.

Abstract: Controlling execution of image processing that adjusts an amount of a printing material applied to the printing medium based on an amount of change of pixel values of image data.

Abstract: An image processing apparatus decides first growth points indicating positions at which dots for generating a screen having a low ruling are generated based on a predetermined screen ruling and screen angle, and second growth points that indicate positions at which dots for increasing the screen ruling of a screen represented by the first growth points are generated. The apparatus generates a screen for growing, in accordance with increase in pixel values of an input image, dots generated centered on the first growth points, and switching, when the pixel values exceed a threshold value, growth points from the first growth points to the second growth points, and growing, in accordance with increase in the pixel values, dots generated centered on the second growth points, and uses the generated screen for screen processing on image data to be printed.