Image forming apparatus and method for selecting an optimal image space frequency for an output image

• US 7,315,402 B2
• Filed: 03/13/2002
• Issued: 01/01/2008
• Est. Priority Date: 03/16/2001
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Aoyagi, Masato, Takahashi, Hiroshi
• Primary Examiner(s): Grant, II; Jerome
• Application Number:
  US10/095,473
• Publication Number:
  US 20020131061A1
• Time in Patent Office: 2,120 Days
• Field of Search: 358/1.9, 358/3.06, 358 313- 324, 358/533, 358/534, 358/536, 358/1.2, 358/528, 358/449, 358/451, 358/3.11, 358/270, 358/298, 358/299, 358/465, 382/270, 382/298, 382/299
• US Class Current: 358/3.13
• CPC Class Codes: H04N 1/2307 Circuits or arrangements for the control thereof, e.g. using a programmed control device, according to a measured quantity H04N1/27, H04N1/29 take precedence
• CPC Class Codes: H04N 1/2315 according to characteristics of the reproducing apparatus, e.g. capability
• CPC Class Codes: H04N 1/2323 according to characteristics of the reproducing medium, e.g. type, size or availability
• CPC Class Codes: H04N 1/2369 Selecting a particular reproducing mode from amongst a plurality of modes, e.g. paper saving or normal, or simplex or duplex
• CPC Class Codes: H04N 1/3935 with modification of image resolution, i.e. determining the values of picture elements at new relative positions
• CPC Class Codes: H04N 1/4055 producing a clustered dots or a size modulated halftone pattern

Abstract

An image forming apparatus includes an image forming device configured to form an output image using at least two or more image space frequencies and an image size acquisition device configured to recognize a size of the output image. A switching device is configured to select one of the at least two or more image frequencies for the output image according to the size of the output image recognized by the image size acquisition device and to switch the image forming device so as to form the output image using the one of two or more image frequencies.

Claims

1. An image forming apparatus, comprising:

an image forming device configured to form an output image onto a sheet by at least two or more dither patterns;

an image area size acquisition device configured to recognize a size of an area of the output image to be formed on the sheet;

a switching device configured to select one of the at least two or more dither patterns for the output image according to the size of the area of the output image recognized by the image area size acquisition device and to switch the image forming device so as to form the output image by the one of the at least two or more dither patterns;

wherein the image size acquisition device is configured to recognize, when the output image includes a plurality of output images in a same page, respective sizes of the plurality of output images in the same page, and

wherein the switching device is configured to select, when the output image includes a plurality of output images in a same page, one of the at least two or more dither patterns for the plurality of output images in the same page based on one of the respective sizes of the plurality of output images in the same page recognized by the image acquisition device, and to switch the image forming device so as to form each of the plurality of output images in the same page using the one of at least two or more dither patterns.

2. An image forming apparatus, comprising:

an image forming device configured to form an output image onto a sheet by at least two or more dither patterns;

an image area size acquisition device configured to recognize a size of an area of the output image to be formed on the sheet;

a switching device configured to select one of the at least two or more dither patterns for the output image according to the size of the area of the output image recognized by the image area size acquisition device and to switch the image forming device so as to form the output image by the one of the at least two or more dither patterns;

wherein the image area size acquisition device is configured to recognize, when the output image includes a plurality of output images in a same file, respective sizes of the plurality of output images in the same file, and

wherein the switching device is configured to select, when the output image includes a plurality of output images in a same file, one of the at least two or more dither patterns for the plurality of output images in the same file based on one of the respective sizes of the plurality of output images in the same file recognized by the image acquisition device, and to switch the image forming device so as to form each of the plurality of output images in the same file using the one of at least two or more dither patterns.

3. An image forming apparatus, comprising:

an image forming device configured to form an output image onto a sheet by at least two or more dither patterns;

an image area size acquisition device configured to recognize a size of an area of the output image to be formed on the sheet;

a switching device configured to select one of the at least two or more dither patterns for the output image according to the size of the area of the output image recognized by the image area size acquisition device and to switch the image forming device so as to form the output image by the one of the at least two or more dither patterns;

wherein the image forming device includes a plurality of dither patterns, each having a substantially same basic tone; and

wherein the plurality of dither patterns have predetermined screen angles respectively that are substantially identical to each other.

4. An image forming apparatus, comprising:

an image forming device configured to form an output image outputted onto a sheet by at least two or more dither patterns;

an output size acquisition device configured to recognize a size of an output sheet for the output image;

a switching device configured to select one of the at least two or more dither patterns for the output image according to the size of the output sheet size for the output image recognized by the output size acquisition device and to switch the image forming device so as to form the output image using the one of the at least two or more dither patterns;

wherein the image forming device includes a plurality of dither patterns, each having a substantially same basic tone; and

wherein the plurality of dither patterns have predetermined screen angles respectively that are substantially identical to each other.

5. An image forming apparatus, comprising:

an image forming device configured to form an output image onto a sheet by at least two or more dither patterns;

an output size acquisition device configured to recognize a size of an output sheet for the output image;

an image area size acquisition device configured to recognize a size of the area of the output image to be formed on the sheet;

a switching device configured to select one of the at least two or more dither patterns for the output image according to the size of an area of the output image recognized by the output area size acquisition device and the size of the area of the output image recognized by the image area size acquisition device and to switch the image forming device so as to form the output image using the one of at least two or more dither patterns;

wherein the image forming device includes a plurality of dither patterns, each having a substantially same basic tone; and

wherein the plurality of dither patterns have predetermined screen angles respectively that are substantially identical to each other.

6. An image forming method, comprising the steps of:

recognizing a size of an output image;

selecting one of at least two or more dither patterns for the output image based on the size of an area of the output image recognized in the recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein when the output image includes a plurality of output images in a same page, the recognizing step includes recognizing respective sizes of the plurality of output images in the same page, the selecting step includes selecting one of at least two or more dither patterns for the plurality of output images in the same page according to one of the respective sizes of the plurality of output images in the same page, and the image forming steps includes forming each of the plurality of output images in the same page using the one of at least two or more dither patterns selected in the selecting step for the plurality of output images in the same page.

7. An image forming method, comprising the steps of:

recognizing a size of an output image;

selecting one of at least two or more dither patterns for the output image based on the size of an area of the output image recognized in the recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein when the output image includes a plurality of output images in a same file, the recognizing step includes recognizing respective sizes of the plurality of output images in the same file, the selecting step includes selecting one of at least two or more dither patterns for the plurality of output images in the same file, and the image forming step includes forming each of the plurality of output images in the same file using the one of at least two or more dither patterns selected in the selecting step for the plurality of output images in the same file.

8. An image forming method, comprising the steps of:

recognizing a size of an output image;

selecting one of at least two or more dither patterns for the output image based on the size of an area of the output image recognized in the recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein in the image forming step a plurality of dither patterns have screen angles of predetermined directions respectively that are substantially identical to each other.

9. An image forming method, comprising the steps of:

recognizing a size of an output sheet for an output image;

selecting one of at least two or more dither patterns for the output image based on the size of the output sheet for the output image recognized in the recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein in the image forming step a plurality of dither patterns have screen angles of predetermined directions respectively that are substantially identical to each other.

10. An image forming method, comprising the steps of:

recognizing a size of an area of an output image;

recognizing a size of an output sheet for the output image;

selecting one of at least two or more dither patterns for the output image based on the size of the area of the output image recognized in the output image size recognizing step and the size of the output sheet for the output image recognized in the output sheet size recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein in the image forming step a plurality of dither patterns have screen angles of predetermined directions respectively that are substantially identical to each other.

11. A computer readable medium storing computer program instructions which when executed by a computer performs an image forming operation comprising the steps of:

recognizing a size of an area of an output image;

selecting one of at least two or more dither patterns for the output image based on the size of the area of the output image recognized in the recognizing step;

forming the output image onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein when the output image includes a plurality of output images in a same page, the recognizing step includes recognizing respective sizes of the plurality of output images in the same page, the selecting step includes selecting one of at least two or more dither patterns for the plurality of output images in the same page according to one of the respective sizes of the plurality of output images in the same page, and the image forming steps includes forming each of the plurality of output images in the same page using the one of at least two or more dither patterns selected in the selecting step for the plurality of output images in the same page.

12. A computer readable medium storing computer program instructions which when executed by a computer performs an image forming operation comprising the steps of:

recognizing a size of an area of an output image;

selecting one of at least two or more dither patterns for the output image based on the size of the area of the output image recognized in the recognizing step;

forming the output image onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein when the output image includes a plurality of output images in a same file, the recognizing step includes recognizing respective sizes of the plurality of output images in the same file, the selecting step includes selecting one of at least two or more dither patterns for the plurality of output images in the same file, and the image forming step includes forming each of the plurality of output images in the same file using the one of at least two or more dither patterns selected in the selecting step for the plurality of output images in the same file.

13. A computer readable medium storing computer program instructions which when executed by a computer performs an image forming operation comprising the steps of:

recognizing a size of an area of an output image;

selecting one of at least two or more dither patterns for the output image based on the size of the area of the output image recognized in the recognizing step;

forming the output image onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein in the image forming step a plurality of dither patterns have screen angles of predetermined directions respectively that are substantially identical to each other.

14. A computer readable medium storing computer program instructions which when executed by a computer performs an image forming operation comprising the steps of:

recognizing a size of an output sheet for an output image;

selecting one of at least two or more dither patterns for the output image based on the size of the output sheet for the output image recognized in the recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein in the image forming step a plurality of dither patterns have screen angles of predetermined directions respectively that are substantially identical to each other.

15. A computer readable medium storing computer program instructions which when executed by a computer performs an image forming operation comprising the steps of:

recognizing a size of an area of an output image;

recognizing a size of an output sheet for the output image;

selecting one of at least two or more dither patterns for the output image based on the size of the area of the output image recognized in the output image size recognizing step and the size of the output sheet for the output image recognized in the output sheet size recognizing step;

forming the output image outputted onto a sheet using the one of at least two or more dither patterns selected in the selecting step; and

wherein in the image forming step a plurality of dither patterns have screen angles of predetermined directions respectively that are substantially identical to each other.

16. An image forming apparatus, comprising:

an image forming device configured to form an output image by at least two or more dither patterns;

an image area size acquisition device configured to recognize a size of an area of the output image;

image contents acquisition device configured to recognize contents of the output image; and

switching device configured to select one of the at least two or more dither patterns for the output image according to the size of the output image recognized by the image area size acquisition device and the contents of the output image recognized by the image contents acquisition device and to switch the image forming device so as to form the output image using the one of the at least two or more dither patterns.

17. An image forming method, comprising the steps of:

recognizing a size of an output image;

recognizing contents of the output image;

selecting one of at least two or more dither patterns for the output image based on the size of an area of the output image recognized in the image size recognizing step and the contents of the output image recognized in the image contents recognizing step; and

forming the output image using the one of at least two or more dither patterns selected in the selecting step.

18. A computer readable medium storing computer program instructions which when executed by a computer performs an image forming operation comprising the steps of:

recognizing a size of an area of an output image;

recognizing contents of the output image;

selecting one of at least two or more dither patterns for the output image based on the size of the area of the output image recognized in the image size recognizing step and the contents of the output image recognized in the image contents recognizing step; and

forming the output image using the one of at least two or more dither patterns selected in the selecting step.