Image processing method and image forming device

1. An image processing method used in an image forming in which ink drops are discharged from a plurality of recording elements of a recording head toward a recording medium as the recording head and the recording medium are moved relative to each other to convert an input image having an M number of tones into an image having an N number of tones (N<M) on the recording medium, the method comprising:

a characteristic information acquiring step of acquiring recording characteristic information of the recording elements;

an inconsistent density correction information calculating step of obtaining inconsistent density correction information from the recording characteristic information acquired in the characteristic information acquiring step;

a density correction processing step of obtaining inconsistency corrected image data from the inconsistent density correction information and data of the input image;

an unfit image detection step of generating inconsistency correction unfit image position information by detecting an inconsistency correction unfit image from data of the input image;

an N-value conversion processing step of obtaining image data having an N number of tones from the inconsistency corrected image data;

an image anomaly judgment processing step of judging whether non-correctable conditions arise according to the inconsistent density correction information and the inconsistency correction unfit image position information; and

an image anomaly alerting step of alerting a user to an image anomaly according to judgment results given in the image anomaly judgment processing step.

2. The image processing method according to claim 1 , wherein the unfit image detection step is performed to detect a line-work image.

3. An image processing method according to claim 1 , further comprising a treatment instruction receiving step of allowing the user to select a treatment in response to occurrence of a predetermined abnormal image.

4. An image forming device comprising:

printing means including a full-line type recording head having a plurality of recording elements arranged over a length corresponding to a full width of a recording medium;

transporting means that moves the recording head relative to the recording medium by moving at least one of the recording head and the recording medium;

information acquiring means that acquires information indicating recording characteristics including a recording position error and discharge failure of the recording elements;

inconsistent density correction information calculating means that obtains inconsistent density correction information based on the recording characteristic information acquired by the information acquiring means;

density correction processing means that obtains inconsistency corrected image data from the inconsistent density correction information and data of the input image;

unfit image detection means that generates inconsistency correction unfit image position information by detecting an inconsistency correction unfit image from data of the input image;

N-value conversion processing means that obtains image data having an N number of tones from the inconsistency corrected image data;

image anomaly judgment processing means that judges whether non-correctable conditions arise according to the inconsistent density correction information and the inconsistency correction unfit image position information; and

image anomaly alert means that alerts a user to an image anomaly according to judgment results given by the image anomaly judgment processing means.

5. The image forming device according to claim 4 , wherein the unfit image detection means detects a line-work image.

6. The image forming device according to claim 4 , further comprising treatment instruction receiving means that allows the user to select a treatment in response to occurrence of a predetermined abnormal image.