Image processing device, print control device, image processing method, and recording medium

An image processing apparatus that converts image data representing a tone value of each pixel with regard to each of multiple colors into intermediate data representing dot creation densities of variable dots, that is, a first dot, a second dot, and a third dot, which have different tone values expressed by respective single dots, and determines on-off state of each of the variable dots in each pixel based on the converted intermediate data, thereby converting the image data into dot data expressed by the on-off state of the each variable dot with regard to each of the multiple colors,

• said image processing apparatus comprising:
• a first image data conversion module that converts the image data of a first color into the dot data with regard to each of the multiple colors, where the first color is selected in advance among the multiple colors such that conspicuousness of a dot having a largest tone value expressible for each color is in an allowable range when an image is formed according to the dot data;
• and
• a second image data conversion module that converts the image data of a second color into the dot data with regard to each of the multiple colors, where the second color is selected among the multiple colors except the first color,
• said first image data conversion module comprising:
• a first intermediate data conversion sub-module that converts the image data of the first color into first intermediate data representing a sum of dot creation density of the first dot and dot creation density of the third dot among the variable dots, where the first dot has a smallest tone value expressed among the variable dots and the third dot has a largest tone value expressed among the variable dots;
• a second intermediate data conversion sub-module that converts the image data of the first color into second intermediate data representing a sum of dot creation density of the second dot and dot creation density of the third dot among the variable dots;
• a first dot creation specification sub-module that specifies the on-off state of the first dot in each pixel, based on the first intermediate data;
• a second dot creation specification sub-module that specifies the on-off state of the second dot in each pixel, based on the second intermediate data;
• and
• a third dot creation specification sub-module that specifies creation of the third dot in place of the first dot and the second dot, in a pixel where both the first dot and the second dot are specified to be in the on state,
• said second image data conversion module comprising:
• a variable dot intermediate data conversion sub-module that converts the image data of the second color into intermediate data representing a dot creation density of each of the variable dots or the first through the third dots;
• and
• a variable dot creation specification sub-module that specifies on-off state of each of the variable dots in each pixel, based on the intermediate data.

A print control apparatus that converts image data representing a tone value of each pixel into intermediate data representing dot creation densities of variable dots, that is, a first dot, a second dot, and a third dot, which have different tone values expressed by respective single dots, and determines on-off state of each of the variable dots in each pixel based on the converted intermediate data, thus converting the image data into dot data expressed by the on-off state of the each variable dot, said print control apparatus outputting the converted dot data to a printing device that creates ink dots on a printing medium to print an image and thereby controls said printing device,

• said print control apparatus comprising:
• a first intermediate data conversion module that converts the image data into first intermediate data representing a sum of dot creation density of the first dot and dot creation density of the third dot among the variable dots;
• a second intermediate data conversion module that converts the image data into second intermediate data representing a sum of dot creation density of the second dot and dot creation density of the third dot among the variable dots;
• a first dot creation specification module that specifies the on-off state of the first dot in each pixel, based on the first intermediate data;
• a second dot creation specification module that specifies the on-off state of the second dot in each pixel, based on the second intermediate data;
• a dot data conversion module that converts a result of specification representing the on-off state of the first dot and the second dot into the dot data in a pixel where both the first dot and the second dot are specified in the on state;
• and
• a dot data output module that outputs the dot data to said printing device.

An image processing method that converts image data representing a tone value of each pixel into intermediate data representing dot creation densities of variable dots, that is, a first dot, a second dot, and a third dot, which have different tone values expressed by respective single dots, and determines on-off state of each of the variable dots in each pixel based on the converted intermediate data, thereby converting the image data into dot data expressed by the on-off state of the each variable dot,

• said image processing method comprising the steps of:
• converting the image data into first intermediate data representing a sum of dot creation density of the first dot and dot creation density of the third dot among the variable dots;
• converting the image data into second intermediate data representing a sum of dot creation density of the second dot and dot creation density of the third dot among the variable dots;
• specifying the on-off state of the first dot in each pixel, based on the first intermediate data;
• specifying the on-off state of the second dot in each pixel, based on the second intermediate data;
• and
• specifying creation of the third dot in place of the first dot and the second dot, in a pixel where both the first dot and the second dot are specified to be in the on state.

A recording medium in which a computer program is recorded, said computer program actualizing a method that converts image data representing a tone value of each pixel into intermediate data representing dot creation densities of variable dots, that is, a first dot, a second dot, and a third dot, which have different tone values expressed by respective single dots, and determines on-off state of each of the variable dots in each pixel based on the converted intermediate data, thereby converting the image data into dot data expressed by the on-off state of the each variable dot,

• said computer program causing a computer to attain the functions of:
• converting the image data into first intermediate data representing a sum of dot creation density of the first dot and dot creation density of the third dot among the variable dots;
• converting the image data into second intermediate data representing a sum of dot creation density of the second dot and dot creation density of the third dot among the variable dots;
• specifying the on-off state of the first dot in each pixel, based on the first intermediate data;
• specifying the on-off state of the second dot in each pixel, based on the second intermediate data;
• and
• specifying creation of the third dot in place of the first dot and the second dot, in a pixel where both the first dot and the second dot are specified to be in the on state.

A computer program causing a computer to actualize a method that converts image data representing a tone value of each pixel into intermediate data representing dot creation densities of variable dots, that is, a first dot, a second dot, and a third dot, which have different tone values expressed by respective single dots, and determines on-off state of each of the variable dots in each pixel based on the converted intermediate data, thereby converting the image data into dot data expressed by the on-off state of the each variable dot,

• said computer program causing the computer to attain the functions of:
• converting the image data into first intermediate data representing a sum of dot creation density of the first dot and dot creation density of the third dot among the variable dots;
• converting the image data into second intermediate data representing a sum of dot creation density of the second dot and dot creation density of the third dot among the variable dots;
• specifying the on-off state of the first dot in each pixel, based on the first intermediate data;
• specifying the on-off state of the second dot in each pixel, based on the second intermediate data;
• and
• specifying creation of the third dot in place of the first dot and the second dot, in a pixel where both the first dot and the second dot are specified to be in the on state.