Image forming apparatus

1. An image forming apparatus comprising:

an extraction unit configured to extract an image for position detection from job image data;

a first image forming unit configured to form the image for position detection on a recording medium;

a second image forming unit disposed on a downstream in a feeding direction of the recording medium relative to the first image forming unit;

a first detection unit configured to detect the image for position detection formed by the first image forming unit; and

a determining unit configured to determine a correction amount of an image forming position of the second image forming unit based on a position of the image for position detection that is detected by the detection unit and a position of the image for position detection in the image data.

2. The image forming apparatus according to claim 1 , further comprising:

a second detection unit that is disposed on a downstream in the feeding direction of the second image forming unit, the second detection unit being configured to detect the image for position detection formed by the first image forming unit; and

a third image forming unit disposed on a downstream in the feeding direction of the second detection unit, wherein

the first detection unit is disposed on an upstream in the feeding direction relative to the second image forming unit and on a downstream in the feeding direction relative to the first image forming unit, and

the determining unit is configured to determine a correction amount of an image forming position of the third image forming unit based on a position of an image for position detection that is detected by the second detection unit and a position of the image for position detection in the job image data.

3. The image forming apparatus according to claim 2 ,

wherein the extraction unit is configured to extract a single image configured with only an image formed by the first image forming unit as the image for position detection.

4. The image forming apparatus according to claim 3 , wherein

the extraction unit is configured to extract a first image formed by the first image forming unit and a second image formed by the second image forming unit as the image for position detection in a case where the job image data does not include the single image, and

the determining unit is configured to determine

a correction amount of a formation position of the second image forming unit based on a position of the first image detected by the first detection unit and a position of the first image in the image data, and

a correction amount of a formation position of the third image forming unit based on a position of the second image detected by the second detection unit and a position of the second image in the image data.

5. The image forming apparatus according to claim 4 ,

wherein the extraction unit extracts a processing mark as an image for position detection.

6. The image forming apparatus according to claim 5 ,

wherein the extraction unit is configured to extract the processing mark with priority over other images when the processing mark is included in the image data.

7. The image forming apparatus according to claim 1 ,

wherein the extraction unit extracts a processing mark as an image for position detection.

8. The image forming apparatus according to claim 7 ,

wherein the extraction unit is configured to extract the processing mark with priority over other images when the processing mark is included in the image data.

9. The image forming apparatus according to claim 1 , wherein

the first detection unit is disposed on a downstream in the feeding direction relative to the second image forming unit,

the first extraction unit is configured to extract a first image formed by the first image forming unit and a second image formed by the second image forming unit as the images for position detection, and

the determining unit is configured to determine a correction amount of a formation position of the second image forming unit based on:

a first difference between a position of the first image detected by the detection unit and a position of the first image in the image data; and

a second difference between a position of the second image detected by the detection unit and a position of the second image in the image data.

10. The image forming apparatus according to claim 1 , wherein

the first detection unit has a length that is equal to or larger than a width of an image region of the recording medium.

11. The image forming apparatus according to claim 10 , wherein

the first detection unit has a length that is equal to or larger than a width of the recording medium.

12. The image forming apparatus according to claim 1 , further comprising

a reception unit configured to receive an instruction designating the image for position detection.

13. The image forming apparatus according to claim 1 , further comprising

a correction unit configured to correct the image forming position based on the correction amount determined by the determining unit.

14. The image forming apparatus according to claim 2 ,

wherein the extraction unit extracts a processing mark as an image for position detection.

15. The image forming apparatus according to claim 14 ,

wherein the extraction unit is configured to extract the processing mark with priority over other images when the processing mark is included in the image data.

16. The image forming apparatus according to claim 2 , wherein

the first detection unit is disposed on a downstream in the feeding direction relative to the second image forming unit,

the first extraction unit is configured to extract a first image formed by the first image forming unit and a second image formed by the second image forming unit as the images for position detection, and

the determining unit is configured to determine a correction amount of a formation position of the second image forming unit based on:

a first difference between a position of the first image detected by the detection unit and a position of the first image in the image data; and

a second difference between a position of the second image detected by the detection unit and a position of the second image in the image data.

17. The image forming apparatus according to claim 3 ,

wherein the extraction unit extracts a processing mark as an image for position detection.

18. The image forming apparatus according to claim 17 ,

wherein the extraction unit is configured to extract the processing mark with priority over other images when the processing mark is included in the image data.

19. The image forming apparatus according to claim 3 , wherein

the first detection unit is disposed on a downstream in the feeding direction relative to the second image forming unit,

the first extraction unit is configured to extract a first image formed by the first image forming unit and a second image formed by the second image forming unit as the images for position detection, and

the determining unit is configured to determine a correction amount of a formation position of the second image forming unit based on:

a first difference between a position of the first image detected by the detection unit and a position of the first image in the image data; and

a second difference between a position of the second image detected by the detection unit and a position of the second image in the image data.

20. The image forming apparatus according to claim 4 , wherein

the first detection unit is disposed on a downstream in the feeding direction relative to the second image forming unit,

the first extraction unit is configured to extract a first image formed by the first image forming unit and a second image formed by the second image forming unit as the images for position detection, and

the determining unit is configured to determine a correction amount of a formation position of the second image forming unit based on:

a first difference between a position of the first image detected by the detection unit and a position of the first image in the image data; and

a second difference between a position of the second image detected by the detection unit and a position of the second image in the image data.