Pseudo-halftoning device, image forming apparatus, and image forming system

An image forming system comprising:

• a pseudo-halftoning device;
• an image forming apparatus that forms a toner image on a recording medium;
• and
• a reading apparatus that reads the toner image on the recording medium, wherein
• the pseudo-halftoning device is such that
• pseudo-halftoning is performed on a target image by using a threshold matrix set including a plurality of threshold matrices,
• one threshold matrix for use is selected from the threshold matrix set according to a position of the target image to be used in the pseudo-halftoning performed on the target image,
• the threshold matrices in the threshold matrix set are generated from a same parent matrix having a higher degree of freedom in number of gray levels, and
• a gradation characteristic of a threshold matrix generated from the parent matrix is generated based on toner-image information data obtained by reading the toner image by the reading apparatus.

An image forming system comprising:

• a pseudo-halftoning device;
• an image forming apparatus that forms a toner image on a recording medium;
• and
• a reading apparatus that reads the toner image on the recording medium, wherein
• the pseudo-halftoning device is such that
• pseudo-halftoning is performed on a target image by using a threshold matrix,
• a parent matrix having a greater number of gray levels than number of gray levels of the target image is included,
• a threshold-value generating device is included, which generates, from the parent matrix, a threshold value used when performing the pseudo-halftoning on the target image,
• the threshold-value generating device generates a threshold value that varies according to a position of the target image and uses generated threshold value in the pseudo-halftoning performed on the target image, and
• the threshold value generated from the parent matrix is determined based on toner-image information data obtained by reading the toner image by the reading apparatus.

An image forming apparatus comprising:

• a pseudo-halftoning unit;
• an image forming unit that forms a toner image on a recording medium;
• and
• a reading unit that read the toner image on the recording medium, wherein the pseudo-halftoning unit is such that
• pseudo-halftoning is performed on a target image by using a threshold matrix set including a plurality of threshold matrices,
• one threshold matrix for use is selected from the threshold matrix set according to a position of the target image to be used in the pseudo-halftoning performed on the target image,
• the threshold matrices in the threshold matrix set are identical with one another in periodic structure but different from one another only in a gradation characteristic, and
• a threshold matrix to be used is determined based on toner-image information data obtained by reading the toner image by the reading unit.