Inspection device and inspection method

1 . An inspection device configured to inspect a printed state of an inspected object surface which is a printed metallic base, the inspection device comprising:

a processor; and

a memory connected to the processor to be able to communicate with the processor,

the processor being configured to:

acquire inspection image data obtained by imaging the inspected object surface;

measure an L* value for each of colors in an L*a*b* colorimetric system of the inspection image data; and

inspect the printed state of the inspected object surface based on a difference value ΔL* between the L* value of the Lab* colorimetric system of standard image data as an inspection standard and the L* value of the Lab* colorimetric system of the inspection image data.

2 . The inspection device according to one of claim 1 , wherein:

the inspection image data is first image data obtained by irradiating the inspected object surface with light emitted from a light source, and receiving reflected light including regularly reflected light and irregularly reflected light from the inspected object surface by a line sensor; and

the processor is further configured to inspect the printed state of the inspected object surface, based on first L* value of the first image data.

3 . The inspection device according to claim 2 , wherein the processor is further configured to inspect the printed state of a region of the inspected object surface based on the first L* value, the region being printed in at least colors other than white.

4 . The inspection device according to one of claim 1 , wherein:

the inspection image data is second image data obtained by irradiating the inspected object surface with light emitted from a light source, and receiving only irregularly reflected light from the inspected object surface by a line sensor; and

the processor is further configured to inspect the printed state of the inspected object surface, based on second L* value of the second image data.

5 . The inspection device according to claim 4 , wherein the processor is further configured to inspect the printed state of a region of the inspected object surface based on the second L* value, the region being printed in at least white.

6 . The inspection device according to claim 1 , wherein the inspection image data includes:

first image data obtained by irradiating the inspected object surface with light emitted from a light source, and receiving reflected light including regularly reflected light and irregularly reflected light from the inspected object surface by a line sensor; and

second image data obtained by irradiating the inspected object surface with light emitted from a light source, and receiving only irregularly reflected light from the inspected object surface by the line sensor, and

the processor is further configured to inspect the printed state of the inspected object surface based on a first L* value of the first image data and a second L* value of the second image data.

7 . The inspection device according to claim 2 , wherein:

at least part of the inspected object surface is a curved surface protruding to the light source; and

the processor is further configured to inspect the printed state of the inspected object surface by rotating the inspected object surface around a center of curvature of the curved surface as a rotation axis.

8 . An inspection method for inspecting a printed state of an inspected object surface which is a printed metallic base, the inspection method comprising:

acquiring inspection image data obtained by imaging the inspected object surface;

measuring an L* value for each of colors in an L*a*b* colorimetric system of the inspection image data; and

inspecting the printed state of the inspected object surface based on a difference value ΔL* between the L* value of the Lab* colorimetric system of standard image data as an inspection standard and the L* value of the Lab* colorimetric system of the inspection image data.