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

• US 20110222125A1
• Filed: 03/01/2011
• Published: 09/15/2011
• Est. Priority Date: 03/09/2010
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Sone, Takuroh, Yasutomi, Kei, Funahashi, Kazuki
• Granted Patent: US 8,553,287 B2
• Time in Patent Office: Days
• US Class Current: 358/3.06
• CPC Class Codes: H04N 1/4053 with threshold modulated relative to input image data or vice versa
• CPC Class Codes: H04N 1/4058 with details for producing a halftone screen at an oblique angle H04N1/4056 takes precedence

Abstract

An image forming system includes a pseudo-halftoning device; an image forming apparatus that forms a toner image on a recording medium; and a reading apparatus that read the toner image on the recording medium, in which 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 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 apparatus.

Claims

1. 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 read 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 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 apparatus.

2. The image forming system according to claim 1, wherein in the pseudo-halftoning device, not all of segments, to which different gradation characteristics are to be applied, have a same size.

3. The image forming system according to claim 1, wherein in the pseudo-halftoning device, number of segments, which are segmented according to a gradation characteristic and to which different gradation characteristics are to be applied, is in a range of three to ten in each of a length direction and a width direction when the recording medium is an A3-size recording medium.

4. The image forming system according to claim 1, wherein in the pseudo-halftoning device, a periodicity of segments, to which different gradation characteristics are to be applied, matches a periodicity other than a size of the recording medium.

5. The image forming system according to claim 1, wherein the reading apparatus obtains the toner-image information data by reading toner images on a plurality of recording media.

6. 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.

7. The image forming system according to claim 6, wherein in the pseudo-halftoning device, not all of segments, to which different gradation characteristics are to be applied, have a same size.

8. The image forming system according to claim 6, wherein in the pseudo-halftoning device, number of segments, which are segmented according to a gradation characteristic and to which different gradation characteristics are to be applied, is in a range of three to ten in each of a length direction and a width direction when the recording medium is an A3-size recording medium.

9. The image forming system according to claim 6, wherein in the pseudo-halftoning device, a periodicity of segments, to which different gradation characteristics are to be applied, matches a periodicity other than a size of the recording medium.

10. The image forming system according to claim 6, wherein the reading apparatus obtains the toner-image information data by reading toner images on a plurality of recording media.

11. 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.

12. The image forming system according to claim 11, wherein in the pseudo-halftoning device, not all of segments, to which different gradation characteristics are to be applied, have a same size.

13. The image forming system according to claim 11, wherein in the pseudo-halftoning device, number of segments, which are segmented according to a gradation characteristic and to which different gradation characteristics are to be applied, is in a range of three to ten in each of a length direction and a width direction when the recording medium is an A3-size recording medium.

14. The image forming system according to claim 11, wherein in the pseudo-halftoning device, a periodicity of segments, to which different gradation characteristics are to be applied, matches a periodicity other than a size of the recording medium.

15. The image forming system according to claim 11, wherein the reading apparatus obtains the toner-image information data by reading toner images on a plurality of recording media.

16. 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.