Image forming apparatus and registration inspection method of image forming apparatus

Abstract

An image forming apparatus for forming a print image, which is composed of a first color image and a second color image, on a print medium, including: a test pattern printing portion that prints a test pattern including the first color and the second color; an image pickup portion that pictures an image of the test pattern printed by the test pattern printing portion; and a registration failure discrimination portion that discriminates a registration failure between the first color and the second color according to the pictured image of the test pattern pictured by the image pickup portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described in detail based on the following figures, wherein:

FIG. 1 is a block diagram showing control configuration related to registration inspection and registration correction of an image forming apparatus of the invention;

FIG. 2 is an image diagram showing an example of a test pattern;

FIG. 3 is a diagram showing an example of test pattern definition information;

FIG. 4A and FIG. 4B are diagrams showing examples of scanned images of test patterns in a case where registration displacement has occurred in a main scanning direction of a plus-one-color image forming section;

FIG. 5A and FIG. 5B are diagrams showing examples of scanned images of test patterns in a case where registration displacement has occurred in a sub-scanning direction of a plus-one-color image forming section;

FIG. 6 is a diagram showing an example of a scanned image of a test pattern in a case where registration displacement has occurred in both a main scanning direction and a sub-scanning direction of a plus-one-color image forming section;

FIG. 7 is a flow chart showing operations for registration displacement detection and correction processing; and

FIG. 8 is a diagram showing a modified example of test pattern images.

Claims

1. An image forming apparatus for forming a print image, which is composed of a first color image and a second color image, on a print medium, comprising: a test pattern printing portion that prints a test pattern including the first color and the second color;an image pickup portion that pictures an image of the test pattern printed by the test pattern printing portion; anda registration failure discrimination portion that discriminates a registration failure between the first color and the second color according to the pictured image of the test pattern pictured by the image pickup portion.

2. The image forming apparatus according to claim 1, wherein: the test pattern is formed of a lattice-shaped pattern that the first color and the second color have a same area when the first color and the second color do not have a registration failure, andthe registration failure discrimination portion judges as the registration failure when a ratio of either the first color or the second color of the pictured image to the area of another color becomes a prescribed value or less.

3. The image forming apparatus according to claim 1, further comprising: a first detecting portion that detects a first displacement amount in a main scanning direction of the pictured image,a second detecting portion that detects a second displacement amount in a sub-scanning direction of the pictured image, anda registration correction portion that performs registration correction in the main scanning direction of the first color and the second color according to the first displacement amount detected by the first detecting portion and performs registration correction in the sub-scanning direction of the first color and the second color according to the second displacement amount detected by the second detecting portion.

4. The image forming apparatus according to claim 2, further comprising: a first detecting portion that detects a first displacement amount in a main scanning direction of the pictured image,a second detecting portion that detects a second displacement amount in a sub-scanning direction of the pictured image, anda registration correction portion that performs registration correction in the main scanning direction of the first color and the second color according to the first displacement amount detected by the first detecting portion and performs registration correction in the sub-scanning direction of the first color and the second color according to the second displacement amount detected by the second detecting portion.

5. A registration inspection method of an image forming apparatus that forms a print image, which is composed of a first color image and a second color image, on a print medium, comprising: printing a test pattern including the first color and the second color,picturing an image of the printed test pattern, andjudging a failure of registration of the first color and the second color according to the pictured image of the test pattern.