Tint block image generation program and tint block image generation device

A non-transitory computer-readable medium which stores an image generation program for causing a computer to execute an image generation step of generating image data for forming, on a print medium, an image including a first image portion and a second image portion, wherein the image generation step comprises:

• a first screen processing step of generating image data by an area modulation screen having a first screen ruling, for pixels of the first image portion;
• and
• a second screen processing step of generating image data by an area modulation screen or a density modulation screen having a second screen ruling which is higher than the first screen ruling, for pixels of the second image portion, wherein
• in the first screen processing step, a halftone dot is generated at a center of gravity position of an image of the first image portion in a cell corresponding to a halftone dot formation area in the area modulation screen processing, when the image of the first image portion and the image of the second image portion exist in the cell.

A tint block image generation device that generates, on a print medium, a tint block image including a latent image portion and a background portion having different output densities to be reproduced by copying, comprising:

• a first screen processing unit which generates latent image portion image data by an area modulation screen having a first screen ruling, for pixels of the latent image portion;
• and
• a second screen processing unit which generates background portion image data by an area modulation screen or a density modulation screen having a second screen ruling which is higher than the first screen ruling, for pixels of the background portion, wherein
• the first screen processing unit generates the latent image portion image data for forming a halftone dot at a center of gravity position of an image of the latent image portion in a cell corresponding to a halftone dot formation area in the area modulation screen, when the image of the latent image portion and the image of the background portion exist in the cell.

An image generation device that generates, on a print medium, an image including a first image portion and a second image portion, comprising:

• a first screen processing unit which generates image data by an area modulation screen having a first screen ruling, for pixels of the first image portion;
• and
• a second screen processing unit which generates image data by an area modulation screen or a density modulation screen having a second screen ruling which is higher than the first screen ruling for pixels of the second image portion, wherein
• the first screen processing unit generates a halftone dot at a center of gravity position of an image of the first image portion in a cell corresponding to a halftone dot formation area in the area modulation screen processing, when the image of the first image portion and the image of the second image portion exist in the cell.