Image-forming apparatus and image-forming method for forming a density correction image

1. An image-forming apparatus comprising:

a forming unit that forms an image on an image holder that is a rotating body holding an image;

a measuring unit that measures a rotation amount of the image holder with reference to a certain position on the image holder;

a determining unit that:

identifies a position on the image holder from which an image is to be formed by the forming unit, according to the rotation amount measured by the measuring unit;

if, while a plurality of images are successively formed on the image holder, an image for density correction is to be formed, postpones forming of the image for density correction until a timing arrives at which one image of the plurality of images is to be formed from a predetermined position on the image holder, and

when the timing arrives at which the one image of the plurality of images is to be formed from the predetermined position on the image holder, determines to start forming of the image for density correction from the predetermined position, instead of forming the one image of the plurality of images; and

a correction unit that obtains a reading result of the image for density correction formed by the forming unit from the predetermined position, and corrects a density of at least one of the plurality of images on the basis of the obtained reading result,

wherein:

if, while a plurality of images are successively formed on the image holder, a timing arrives at which the image for density correction is to be formed, the determining unit specifies a position on the image holder from which a first image of the plurality of images is to be formed after the timing,

if the specified position is the predetermined position, the determining unit determines to start forming of the image for density correction from the predetermined position, instead of forming the first image,

if the specified position is not the predetermined position, the determining unit specifies a second image, that is to be formed from the predetermined position earliest of the plurality of images to be formed after the timing, and determines to start forming of the image for density correction from the predetermined position, instead of forming the second image.

2. The image-forming apparatus according to claim 1 , wherein:

if while a plurality of images are successively formed on the image holder, an instruction to immediately form the image for density correction is performed, the determining unit specifies a position on the image holder at which it is possible for the forming unit to form an image in the shortest period after the instruction performed, and determines to start forming the image for density correction from the specified position, even if the specified position is other than the predetermined position.

3. An image-forming method comprising:

forming an image on an image holder that is a rotating body holding an image;

measuring a rotation amount of the image holder with reference to a certain position on the image holder;

identifying a position on the image holder from which an image is to be formed, according to the measured rotation amount;

if, while a plurality of images are successively formed on the image holder, an image for density correction is to be formed, postponing forming of the image for density correction until a timing arrives at which one image of the plurality of images is to be formed from a predetermined position on the image holder, and

when the timing arrives at which the one image of the plurality of images is to be formed from the predetermined position on the image holder, determining to start forming of the image for density correction from the predetermined position, instead of forming the one image of the plurality of images; and

obtaining a reading result of the image for density correction formed from the predetermined position, and correcting a density of at least one of the plurality of images on the basis of the obtained reading result

wherein:

if, while a plurality of images are successively formed on the image holder, a timing arrives at which the image for density correction is to be formed, the determining unit specifies a position on the image holder from which a first image of the plurality of images is to be formed after the timing,

if the specified position is the predetermined position, the determining unit determines to start forming of the image for density correction from the predetermined position, instead of forming the first image,

if the specified position is not the predetermined position, the determining unit specifies a second image, that is to be formed from the predetermined position earliest of the plurality of images to be formed after the timing, and determines to start forming of the image for density correction from the predetermined position, instead of forming the second image.