JPH0731133B2 - Inspection method for photosensitive materials - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for inspecting a light-sensitive material, and more particularly, to inspecting the light-sensitive material by irradiating the light-sensitive material with light having polarized light having a wavelength characteristic that does not substantially expose the light-sensitive material. It relates to an inspection method for performing.

[Background of technology]

In the process of manufacturing a photosensitive material, defects may occur on the surface of the photosensitive material. That is, when the base sheet itself of the light-sensitive material is scratched or bubbles are generated in the coating film during the emulsion coating process, defects are likely to occur on the surface of the light-sensitive material.

As a method of inspecting a photosensitive material for detecting such a defect, conventionally, S-polarized light (polarized light perpendicular to the incident surface) is used, and the surface of the photosensitive material is irradiated with this light to detect reflected light therefrom. There is known an inspection method for detecting defects on the surface by doing.

In the case of a color photographic paper, which is a light-sensitive material, however, the peculiar defect that the dyes of the respective layers constituting the color photographic paper are disturbed and discolored is likely to occur. That is, a color photographic paper is usually formed by simultaneously coating multiple emulsions on a base sheet with a non-photosensitive dye (non-photosensitive dye) added by a slide hopper method or the like. On the sheet, a blue-sensitive regular layer that is sensitive to blue light, a green-sensitive ortho layer that is sensitive to green light, and a red-sensitive pan layer that is sensitive to red light are laminated in this order, and the surface is protected. It is formed by applying layers,
The colorants of different colors contained in each layer may be disturbed, resulting in a defect that the color printing paper is discolored.

[Problems to be solved by the invention]

However, with the conventional inspection method using S-polarized light, defects such as irregularities on the surface of the photosensitive material can be detected with high accuracy, but the accuracy of detecting discoloration defects such as color changes is considerably low. .

The present invention has been made under the circumstances described above, and provides a method for inspecting a photosensitive material capable of increasing the detection accuracy of a discoloration defect.

[Means for solving problems]

The present invention is characterized by using P polarized light as the polarized light in an inspection method of irradiating the photosensitive material with light having polarized light having a wavelength characteristic that does not substantially expose the photosensitive material to the inspection.

[Advantageous effects of the invention]

According to the present invention, since P-polarized light is used as the polarized light, it is possible to detect with high accuracy not only the surface of the photosensitive material but also the discoloration defect that occurs inside.

[Specific configuration of the invention]

 Hereinafter, the present invention will be specifically described.

In the present invention, the inspection is performed by irradiating the photosensitive material with light having P-polarized light (polarized light that is horizontal to the incident surface) having a wavelength characteristic that does not substantially expose the photosensitive material. The specific means for obtaining P-polarized light is not particularly limited.

The light source for obtaining P-polarized light is not particularly limited as long as the light having P-polarized light that directly irradiates the photosensitive material has a wavelength characteristic that does not substantially expose the photosensitive material, and can be appropriately selected. Here, "substantially do not expose"
Means that the sensitivity of the photosensitive material is extremely low or insensitive to the light having P-polarized light that irradiates the photosensitive material. It is inconvenient if the photosensitive material is irradiated with light having P-polarized light so that the photosensitive material is highly sensitive, because the photosensitive material becomes unusable.

For example, as shown in FIG. 1, a light-sensitive material A is coated on a base sheet 61 with an emulsion containing a dye (non-light-sensitive dye) that is not light-sensitive by a slide hopper method or the like at the same time, and is exposed to blue light. A blue-sensitive regular layer 62, a green-sensitive ortho layer 63 that is sensitive to green light, and a red-sensitive pan layer 64 that is dried to red light are laminated in this order, and a protective layer 65 is further laminated on the surface. The specific sensitivities of the regular layer 62, the ortho layer 63, and the pan layer 64 are 350 to 510 nm and 440 to 6 respectively.
In the case of wavelengths in the range of 00 nm and 570 to 770 nm, synthesizing these results in about 550 to 6 as shown in FIG.
Since there is a portion with low specific sensitivity in the wavelength region d of 35 nm, a He-Ne laser having an oscillation wavelength of 632 nm (visible light) can be preferably used as the light source.

FIG. 3 is an example of an inspection apparatus that can be used for implementing the present invention. In the figure, 10 is a light source, 31 is a roll,
32 is a rotary encoder, 33 is a shutter, 34 is an ND filter, 35 is a rotary scanner, 36 is an Fθ lens, 37 is a power monitor, 38 is a scanner rotation detection device, 39 is a mirror, 40 is a light receiving portion for diffuse reflection light, 41 Is a light receiving portion for specular reflection light, 42 is a high-voltage power supply, and 50 is a defective portion due to discoloration.

According to the inspection device, the photosensitive material A can be inspected as follows.

The photosensitive material A is conveyed through the roll 31 at a predetermined speed. The roll 31 is provided with a rotary encoder 32 from which a carrier pulse is output. By forming this carrying pulse, the carrying speed of the photosensitive material A is detected. When the carrying speed is low, a signal is sent to close the shutter 33. This is to prevent fogging of the photosensitive material A.

The light having P-polarized light from the light source 10 is attenuated by the ND filter 34, reflected by the rotary scanner 35, and scans the surface of the photosensitive material A via the Fθ lens 36. ND during inspection
The power monitor 37 detects the reflected light from the filter 34 and constantly monitors the state of the ND filter 34. When an abnormality occurs, the shutter 33 is closed to prevent the fog on the photosensitive material A from occurring.

Further, the light reflected by the rotary scanner 35 is detected by the scanner rotation detection device 38 to constantly monitor the rotation speed of the rotation scanner 35, and when the rotation speed decreases, the shutter 33 is closed. Further, a mirror 39 is arranged between the rotary scanner 35 and the roll 31, so that the origin of the scanning light is detected and the scanning light from the rotary scanner 35 does not cause relative fluctuation for each scanning. Is corrected as follows.

The light receiving section for detecting the reflected light from the surface of the photosensitive material A is composed of a diffused reflected light receiving section 40 and a specular reflected light receiving section 41. A plurality of photomultipliers for converting electricity into electricity and a plurality of preamplifiers arranged at the next stage for amplifying are stored.
The outputs of the plurality of preamplifiers are added by an adding amplifier, and only a defective portion 50 is extracted by a high pass filter, and a detection signal is output.

When the P-polarized light hits the defect portion 50 due to the discoloration of the photosensitive material A, diffuse reflected light is formed. Therefore, the diffuse reflected light is received by the light receiving unit 40 for diffuse reflected light to detect the defect portion 50 with high accuracy. be able to. Since this diffusely reflected light is less likely to be disturbed by the difference in image quality of the photosensitive material A, for example, silk, matte, E surface, glossy, etc.,
The S / N ratio of the detection signal can be maintained large, and the detection accuracy of the defect portion 50 is high. In the case of glossy, the specular reflection light is less likely to be disturbed, so the specular reflection light receiving unit
It is also possible to detect the defective portion 50 by receiving light at 41.

As described above, according to the inspection method of the present invention, since light having P-polarized light is used as the light for irradiating the photosensitive material A, not only the surface of the photosensitive material A but also the defect portion 50 due to discoloration generated inside is high. It is possible to detect with accuracy.

[Experimental example]

Experimental Example 1 As shown in FIG. 4, light having P-polarized light is applied to a defect portion due to discoloration of the photosensitive material A, and the output of diffuse reflected light from this is changed by the optical sensor 71 while changing the light receiving angle x. An experiment was performed to detect. Further, the same experiment as above was performed using light having S-polarized light. The results of these experiments are shown in FIG.

As can be seen from the figure, when the light having the P polarization is used, the region where the light amount of the diffuse reflection light is uniform becomes wider than that when the light having the S polarization is used.
The influence of the formation of the surface of the
It is understood that the amount of reflected light is increased by about 1.3 to 1.4 times, and thus the detection power of the defective portion is increased. Actually, the detection power is S
It has been confirmed that it is about 1.3 to 2.0 times that when using polarized light.

Experimental Example 2 As shown in FIG. 6, a light source 81 composed of a He—Ne laser,
Using the rotary scanner 82 and the shutter 83, an experiment was conducted to irradiate the photosensitive material A with P-polarized light while scanning it with the opening time of the shutter 83 as a parameter. I checked. For comparison, an experiment similar to the above was performed using light having S polarization. The results of these experiments are shown in Table 1.

In Table 1, "1/125 + 1/250" means that the first area was scanned at 1/125 sec and then the same region was scanned at 1/250 sec. The same applies to "1/250 + 1/500". Further, “◯” means that fog did not occur, and “x” means that fog occurred.

As can be understood from the results shown in Table 1, by attenuating the amount of light having P-polarized light, it is possible to detect a defective portion without causing fog.

Experimental Example 3 Three types of defect samples A1 (pinkish bubble tailing), A2 (whiteish tailing), and A3 (pinky bubble tailing) were tested by detecting the defect location due to discoloration. The signal S / N ratio was measured. However, from the results of Experiment 2, P
For polarized light, the shutter open time is 1/250
The light intensity is reduced so that fog does not occur at +1/500, and the light intensity has the same fog safety as the light with S-polarized light. The results are shown in Table 2.

As can be seen from the results in Table 2, the detection power is about 1.4 times or more when the light having P polarization is used as compared with the case where the light having S polarization is used.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of the structure of a light-sensitive material and the specific sensitivity of each emulsion layer, FIG. 2 is a view showing the specific sensitivity of the entire light-sensitive material, and FIG. 3 is an inspection apparatus that can be used for carrying out the present invention. FIG. 4 is a schematic diagram of an experimental apparatus for measuring the amount of diffusely reflected light, FIG. 5 is a diagram showing the relationship between the reflection angle of diffusely reflected light and light output, and FIG. 6 is a fog. FIG. 3 is a schematic view of an experimental device for checking the occurrence of 10 …… Light source, 20 …… Polarization selection means A …… Photosensitive material, 31 …… Roll 32 …… Rotary encoder 33 …… Shutter, 34 …… ND filter 35 …… Rotation scanner, 36 …… Fθ lens 37 …… Power monitor 38 …… Scanner rotation detector 39 …… Mirror, 40 …… Diffuse reflection light receiving part 41 …… Specular reflection light receiving part, 42 …… High voltage power supply 50 …… Defect location, 61 …… Base sheet 62 ...... Pan layer, 63 …… Ortho layer 64 …… Regular layer, 71 …… Optical sensor 81 …… Light source, 82 …… Rotating scanner 83 …… Shutter

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Claims (1)

[Claims] 1. An inspection method for inspecting a photosensitive material by irradiating the photosensitive material with light having polarized light having a wavelength characteristic which does not substantially expose the photosensitive material, wherein P polarized light is used as the polarized light. Inspection method.