Image forming apparatus, image forming method, and storage medium storing program for forming image

Abstract

An image forming apparatus includes a screen processing part that performs a screen processing on image data, a correction processing part that divides the image data subjected to the screen processing into plural regions, determines a correction parameter for each of the regions in response to a characteristic of the screen processing, and performs the correction processing, and an image formation part that forms an image based on the image data subjected to correction processing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the invention will be described in detail based on the following figures, wherein:

FIG. 1 is a view showing a configuration of an image forming apparatus 10 according to an exemplary embodiment of the invention;

FIG. 2 is a view showing a functional configuration of an image processing device 20;

FIGS. 3A to 3C are views for illustrating an insertion method of pixels;

FIGS. 4A and 4B are views showing a periodic structure incorporated in an image by a screen processing;

FIG. 5 is a view for illustrating a correction processing according to the exemplary embodiment of the invention;

FIGS. 6A and 6B are views for illustrating a correction processing to deal with an image deformation in a fixing unit;

FIG. 7 is a view for illustrating a correction processing to deal with an image deformation in a fixing unit;

FIGS. 8A and 8B are views for illustrating a correction processing to deal with an image deformation in a fixing unit;

FIG. 9 is a view for illustrating a correction processing to deal with an image deformation in a fixing unit;

FIG. 10 is a view for illustrating a correction processing to deal with an image deformation due to skewing;

FIG. 11 is a view for illustrating a correction processing to deal with an image deformation due to transfer rotation;

FIGS. 12A to 12D are views for illustrating the details of correction processing to deal with the image deformation due to the transfer rotation;

FIG. 13 is a view for illustrating a correction processing at a first stage to deal with the image deformation due to the transfer rotation;

FIG. 14 is a view for illustrating a correction processing at a second stage to deal with the image deformation due to the transfer rotation;

FIGS. 15A and 15B are views for illustrating a second transfer mechanism;

FIGS. 16A and 16B are views for illustrating an image defect due to belt skewing in a first transfer part;

FIG. 17 is a view for illustrating belt skewing in a second transfer part;

FIG. 18 is a view showing an example of an image distorted by rotation of a sheet in the second transfer part;

FIG. 19 is a view showing an example of sheet deformation in a fixing unit;

FIG. 20 is a view showing an example of sheet deformation in the fixing unit; and

FIGS. 21A and 21B are views showing examples of image deformation in the fixing unit.

Claims

1. An image forming apparatus comprising: a screen processing part that performs a screen processing on image data;a correction processing part that divides the image data subjected to the screen processing into a plurality of regions, determines a correction parameter for each of the regions in response to a characteristic of the screen processing, and performs the correction processing; andan image formation part that forms an image based on the image data subjected to correction processing.

2. The image forming apparatus according to claim 1, further comprising a distortion detection part to detect a distortion of an output image.

3. The image forming apparatus according to claim 2, wherein the correction processing part determines the division number of the regions and the correction parameter according to the distortion detected by the distortion detection part.

4. The image forming apparatus according to claim 1, wherein the characteristic of the screen processing is at least one of a period and an angle of the screen processing, andthe correction processing part selects at least one of a correction period and a correction angle which does not interfere with the at least one of the period and the angle of the screen processing.

5. The image forming apparatus according to claim 4, wherein the correction processing part performs a pixel operation for each line to perform the correction processing, anddetermines a pixel arrangement parameter to make a pixel operation period different from the period of the screen processing.

6. The image forming apparatus according to claim 4, wherein the correction processing part performs a pixel operation for each line to perform the correction processing, anddetermines a pixel arrangement parameter to make a correction angle different from the angle of the screen processing.

7. The image forming apparatus according to claim 1, wherein the plurality of regions are a plurality of band-shaped regions extending in a main scanning direction.

8. The image forming apparatus according to claim 1, wherein the plurality of regions are a plurality of band-shaped regions extending in a sub-scanning direction.

9. The image forming apparatus according to claim 1, wherein the correction processing part combines a plurality of correction processings with different correction parameters to perform the correction processing.

10. The image forming apparatus according to claim 9, wherein the correction processing part combines reduction or enlargement of the regions and movement of the regions to perform the correction processing.

11. The image forming apparatus according to claim 10, wherein the correction processing part displaces positions to be operated in adjacent regions from each other.

12. An image forming method comprising: detecting distortion in an image outputted based on image data;performing screen processing on the image data;dividing the image data into a plurality of regions;determining a pixel arrangement parameter corresponding to a characteristic of the screen processing for each region and a correction amount corresponding to the detected distortion;correcting the image data subjected to the screen processing using the pixel arrangement parameter and the correction amount; andforming an image based on the corrected image data.

13. A storage medium readable by a computer, the storage medium storing a program of instructions executable by the computer to perform a function for forming an image, the function comprising: detecting distortion in an image outputted based on image data;performing screen processing on the image data;dividing the image data into a plurality of regions;determining a pixel arrangement parameter corresponding to a characteristic of the screen processing for each region and a correction amount corresponding to the detected distortion;correcting the image data subjected to the screen processing using the pixel arrangement parameter and the correction amount; andforming an image based on the corrected image data.