Image processing device, cockling detection method, machine learning system
Provided is technology enabling detecting cockling in a print medium without printing a cockling detection pattern on the print medium. An image processing device has: a light source configured to illuminate a print medium; a sensor configured to scan the print medium; and a controller configured to control the light source and sensor. The controller determines if there is cockling in an evaluation area of the print medium based on change in the detection values of the sensor in the evaluation area.
1. An image processing device comprising:
a light source configured to illuminate a print medium;
a sensor configured to scan a cockling evaluation area in the print medium illuminated by the light source; and
a controller configured to control the light source and sensor;
the controller determining if there is cockling based on change in a detection value that is either a gradation value read by the sensor in the evaluation area, or reflectivity acquired by converting the gradation value,
wherein change in the detection value is change from a detection value expected when there is no cockling on the print medium,
a minimum limit of a specific range including a detection value used as a white reference of the print medium is a threshold, and
the controller determines there is cockling when the detection value is less than or equal to the threshold.
2. The image processing device described in claim 1 , wherein:
the detection value used as a white reference of the print medium is a detection value read by the sensor from an area of the print medium that is unprinted and has no cockling.
3. The image processing device described in claim 1 , wherein:
the detection value used as a white reference of the print medium is a detection value acquired when multiple light sources are on.
4. The image processing device described in claim 1 , wherein:
the controller determines there is cockling when change in the detection value in the evaluation area is abrupt and greater than a reference.
5. The image processing device described in claim 1 , wherein:
the controller determines there is cockling when the detection value in the evaluation area drops from a first range to a second range, and then returns to the first range.
6. The image processing device described in claim 1 , wherein:
the controller controls the sensor to scan the print medium when one light source is on.
7. The image processing device described in claim 1 , wherein:
there are N (where N is an integer of two or more) light sources configured to illuminate the evaluation area from mutually different positions; and
the controller causes N light sources or fewer of the N light sources to emit one at a time while the sensor scans the print medium, and determines if cockling is present.
8. The image processing device described in claim 1 , wherein:
at least two of the multiple light sources are disposed to opposing positions.
9. The image processing device described in claim 1 , wherein:
the controller determines if cockling is present in each of multiple evaluation areas in a main scanning direction of the print medium.
10. A cockling detection method comprising:
acquiring a detection value of a sensor that scans a print medium illuminated by a light source; and
determining if there is cockling in an evaluation area of a print medium based on change in a detection value that is either a gradation value read by the sensor in the evaluation area, or reflectivity acquired by converting the gradation value,
wherein change in the detection value is change from a detection value expected when there is no cockling on the print medium,
a minimum limit of a specific range including a detection value used as a white reference of the print medium is a threshold, and
there is cockling when the detection value is less than or equal to the threshold.