JPH0868760A - Surface laser flaw detector - Google Patents

Abstract

PURPOSE: To discriminate the unevenness of the surface flaw of a cylindrical body such as a photosensitive drum or a charge roll by irradiating the surface to be inspected of the cylindrical body with slit inspection light and spot inspection light. CONSTITUTION: The cylindrical surface layer of the object R to be inspected rotated by a support device U1 is irradiated with slit inspection light L1 along the axial direction of the object to be inspected. The spot inspection light L2 emitted from the end part of the object R to be inspected is projected on the surface of the object R to be inspected in almost parallel to the center axis thereof. A line sensor S is arranged so as to detect the regular reflected light of the slit inspection light L1 when there is no uneven flaw on the surface of the object R to be inspected. The scattered reflected light going toward the line sensor S from the surface of the object R to be inspected of the spot inspection light L2 increases at the inclined part on the side near to the emitting position of the light L2 in a protruding flaw and increases in the inclined part on the side remote from the emitting position thereof in a recessed flaw. Therefore, when there is a protruding or recessed flaw, the decrease and increase parts of the quantity of detection light is generated along the axial direction of the object R to be inspected and the protruding and recessed flaws can be discriminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically detects surface defects of a cylindrical inspection object such as a photosensitive drum, a fixing roll, a charging roll, etc. used in an electrophotographic image output device such as a copying machine or a laser printer. Regarding the device to be inspected.

[0002]

2. Description of the Related Art In an electrophotographic image output device such as a copying machine or a laser printer, cylindrical parts such as a photosensitive drum, a heat fixing roll, and a charging roll are important functional parts that influence the quality of an output image. is there. The photosensitive drum is formed by dip coating a multi-layered photosensitive layer on a metal pipe, the heat fixing roll is electrostatically coated with a release layer of fluororesin on the metal pipe, and the charging roll is on a polished rubber roll. It is manufactured by applying a semiconductive surface layer. In the roll manufacturing process, "circumferential scratches" on the roll surface in the cutting and polishing processes of metal pipes, in the coating process non-uniformity of the coating material "contamination" and "color unevenness", and in uneven coating conditions "dents" In terms of handling, there are more than ten types of defects such as "dents" and "scratches".

Since these defects appear as black spots or streaks on the copy surface, the quality is ensured by performing an appearance inspection. When there is a defect on the roll, the defect limit standard determines whether the roll is a defective product or a good product. For each type of roll, the physical quantity such as the position of the defect, the size A, the diameter D, the depth P, the height H, the number M in the entire roll, and the number N per unit area is used,
Limiting standards are stipulated to judge good products and defective products. The mechanism that affects the copy surface depends on the type of defect.

Next, it will be described with reference to FIG. 13 that different influences appear on the copy surface depending on the type of the unevenness of the defect. For example, in the fixing roll, the portion corresponding to the convex defect 01 and the peripheral portion 02 thereof are largely defective in fixing, whereas the concave defect 03 has a portion 04 corresponding to the concave defect.
Only the defect becomes a fixing defect, and the convex defect 01 affects the copy surface more than the concave defect 03. For this reason,
Defect limit standards differ depending on the defect type. The same applies to other types of cylindrical parts. For concave defects and convex defects, which are typical defects among the dozens of types of defects, limit standards are set as shown in Table 1 of FIG. 14, for example. Therefore, it is necessary to determine the defect type and determine whether the product is a good product or a defective product. Conventionally, in the visual inspection of these cylindrical parts, the inspector has identified the defect type and judged the defective product while comparing it with the limit sample sample, but the visual inspection visually increases the inspection cost and inspection man-hours, Problems such as variations in inspection quality and difficulty in securing inspection personnel have been pointed out.
On the other hand, a device for automatically inspecting the appearance of these cylindrical parts has been proposed.

The following technology (J01) is known as an apparatus for automatically inspecting surface layer defects of a cylindrical part (inspection object). (J01) Technology shown in FIG. 15 (technology described in Japanese Patent Laid-Open No. 5-107196) In the conventional surface layer defect detection apparatus shown in FIG. 15, light emitted from a light source 06 such as a fluorescent lamp emitting white diffused light is The slit 07 irradiates the surface of the photosensitive drum (that is, the cylindrical object to be inspected) 08 as strip slit inspection light L1. The photoconductor drum 08 is rotatably driven by a rotation driving means 09 composed of a rotary main shaft 09a and a tailstock shaft 09b which sandwich a central axis between the both ends. While rotating the photoconductor drum 08, the light receiving field of the line sensor S is divided into a bright and dark boundary line portion H1 extending in the longitudinal direction of the strip slit inspection light on the surface (surface layer) thereof.
At the first detection position set to 1 and the second detection position set to the center line portion H2 of the band-shaped slit inspection light in the light-receiving field, defects in the surface layer are detected from the respective detected light amount signals.

That is, in the prior art described in this publication, the first detection position H is detected while rotating the photosensitive drum 08.
In 1, the unevenness of the surface of the surface layer, mechanical scratches, etc. are detected,
At the second detection position H2, the change in the film thickness of the photosensitive layer inside the transparent surface layer, the presence of impurities (foreign matter) in the surface layer, etc. are detected. As a result of the research conducted by the inventor of the present application, in the case of an object to be inspected in which a photosensitive layer is present inside a transparent layer on the surface such as a photosensitive drum, the change in the thickness of the photosensitive layer inside the transparent layer is:
It was found that it is possible to detect with higher accuracy by detecting the amount of scattered reflected light from the portion H3 further outside the boundary portion H1, that is, the portion (dark portion) that is slightly vaguely bright. However, in this case, the amount of light detected by the light receiving element is small, and it takes time to accumulate the light amount of the light receiving element, so it takes time to detect the change in the film thickness. The width of the visual field in the circumferential direction of the roll (cylindrical object to be inspected) that can be measured in the light receiving visual field is 0.5 mm at the slit inspection light boundary line portion H1 and the slit inspection light center line portion in the roll having a diameter of 30 mm. It is about 1 mm for H2 and about 2 mm at the outside of the slit inspection light. The width of the visual field in the circumferential direction of the roll becomes narrower as the roll diameter becomes smaller, which makes it difficult to set the light-receiving visual field of the line sensor.

Next, the principle that unevenness can be detected by the slit inspection light boundary line light receiving system for detecting the reflected light from the boundary line portion H1 will be described with reference to FIG. As shown in FIG. 16A, when there is no defect on the surface, the slit inspection light L1 from the light source 06 is projected on the surface of the photoconductor 08 to form a slit inspection light image 08a, which is directed in the regular reflection direction 011. The reflected light is slightly received on the light receiving optical axis S1 of the line sensor S which receives the boundary portion H1 of the slit inspection light L1 from an angle slightly deviated from the regular reflection direction 011. On the other hand, FIG. 16B
When there is a gentle unevenness 012 on the surface, the reflection direction 013 of the slit inspection light L1 deviates from the regular reflection direction 011 shown in FIG. 16A when there is no unevenness. The amount of detected light increases when the direction of this deviation approaches the received light optical axis S1, and decreases when it departs. Defects can be detected by increasing or decreasing the amount of detected light.

However, in the above method, as the roll diameter becomes smaller, the measurable width of the visual field in the circumferential direction of the roll becomes narrower, which makes it difficult to detect defects. Further, as can be seen from FIG. 16C, in the concave or convex defect 014 generated along the circumferential direction, the extending direction of the defect 014 is along the incident and reflecting directions of the slit inspection light L1.
Light is less likely to be scattered by the defect 014 and reflected only in the specular reflection direction 011. Therefore, detection is difficult. Therefore,
The applicant has already applied for the following technology (J02).

(J02) Technology shown in FIGS. 17 and 18 (Technology described in Japanese Patent Application No. 5-235183) FIG. 17 shows an uneven defect generated in the circumferential direction which is difficult to detect by the method (J01). It is a figure which shows schematic structure of the surface layer defect detection apparatus which targets the roll 08 of a small diameter. The structure of the rotation driving means 9 for the roll 08 shown in FIG. 17 is the same as that shown in FIG. Light source 016 to optical fiber 0
The surface of the roll 08 is irradiated with the spot inspection light L2 having a directivity, which is projected through the 17 and the spot inspection light emitter 018 in a direction substantially parallel to the axial center direction. The light-receiving visual field of the line sensor S is set at the center position of the surface of the roll 08 for the spot inspection light L2. FIG. 18 is an operation explanatory view of the surface device defect detection device shown in FIG. 17, and FIG. 18A shows a roll 08.
FIG. 18 is a diagram showing the reflection direction of the spot inspection light L2 when there is no defect on the surface and when there is a defect, and FIG. 18B is a diagram showing the detected light amount signal of the line sensor S in those cases. In FIG. 18, when there is no unevenness defect, the reflected light of the spot inspection light L2 from the surface of the roll 08 goes in the regular reflection direction, so that it is hardly received by the line sensor S and becomes a low-level normal surface signal 021. When there is a defect 012 on the surface, the spot inspection light L2 irradiated on the surface of the roll 08
Is scattered by a defect and is received by the line sensor S as a defect signal 022. In this method, since the direction of the projected spot inspection light L2 and the direction of the circumferential unevenness defect are perpendicular to each other, light is scattered at the defect portion and the defect can be detected.

[0010]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
1) and (J02) have the following problems. (Problems of (J01) and (J02) above) (J01) and
The method of (J02) is bulge (convex defect) or dent (concave defect)
The presence or absence of such defects can be detected. However, those methods have not been clear about a method and an apparatus for discriminating whether the defect is a convex defect or a concave defect. Therefore, in the inspection apparatus according to the above-mentioned conventional method, in order not to overlook defects, that is, the ratio of the genuine defective products judged by the device to be defective (hereinafter referred to as the detection rate) is 100.
In order to make the percentage, it is necessary to make a judgment according to the one having a stricter defect limit standard among the uneven defects as a judgment standard. For this reason, the rate of determining a roll that is a non-defective product as a non-defective product (hereinafter referred to as a false report) may reach a dozen percent. For example, in the case of a fixing roll, in the case of uneven defects, the standard of convex defects is diameter D = 0.4 mm (see FIG. 14).
In order to match the determination criteria with, the defect which is a defective product from 0.4 mm to 2 mm, which is a concave defect, is determined to be a defective product. For this reason, it is necessary to re-inspect the rolls that have been determined to be defective products and pick out non-defective products by visual inspection by an inspector.

By the way, the following technology (J03) is conventionally known as an apparatus for inspecting irregularities on the surface of a car body, which is different from the technical field of the present invention. (J03) The technique shown in FIGS.
In JP-A-5-45142, an apparatus shown in FIG. 19 is used, and a surface illumination light source having repeated light-dark gradients (see FIG. 20) is used for a coating surface defect on a vehicle body surface 023a of an automobile 023. It is illuminated by 024 and received by the CCD camera 025, and the unevenness defect is discriminated by the brightness of the inspection coated surface which changes according to the convex defect and the concave defect. In FIG. 20, when there is a convex defect inside one change region that changes from dark (a portion having a high vertical line density) to bright (a portion having a low vertical line density), the dark portion a1 and the bright portion a2 are adjacent to each other due to the convex mirror effect. Then, dark changes to bright, and if there is a concave defect, the bright portion a1 ′ and the dark portion a2 ′ become adjacent to each other due to the concave mirror effect, and change from bright to dark. As a result, it is possible to discriminate the unevenness and perform the repair operation according to the type of the defect.

The conventional technique (J03) has the following problems. (Problem of (J03)) The method of (J03) requires a large-scale illumination light source and a flat body-coated surface of a vehicle body, and is a cylindrical inspection object used in a copying machine or a printer. It is difficult to apply to a curved surface having a small radius of curvature (that is, a large curvature) such as a body having a diameter of about 20 mm to 80 mm. Therefore, the present applicant has already applied for the following technology (J04) as a method for detecting the unevenness of a defect in a cylindrical inspection object having a large curvature used in a copying machine or a printer.

(J04) Technology shown in FIGS. 21 and 22 (technology described in Japanese Patent Application No. 6-30105) This technology is based on the slit inspection light boundary line receiving system shown in FIG. A process for extracting a defect image and a defect image in the negative direction, and a processing unit for calculating a feature amount from the surface development image are provided, and a concave defect and a convex defect are generated depending on the order of generation of the extracted defect image in the positive direction and defect image in the negative direction. It is possible to discriminate. Next, a method of discriminating between the concave defect and the convex defect will be described with reference to FIGS. With this method,
As shown in FIG. 1A, the light receiving optical axis (field of view) S1 of the sensor S receives the boundary position (the position indicated by H1 in FIG. 15) of the slit inspection light L1 irradiated on the surface of the roll 08,
The reflected light at a position slightly deviated from the regular reflection direction 011 is received. The defect passes through the field of view of the sensor S while rotating in the sub-scanning direction SS of the roll 08. However, as shown in FIG. 21B, when the first half of the convex defect SW reaches the field of view of the sensor S, the reflection direction of the slit inspection light L1 changes. Varying and convex defects increase the sensor signal compared to normal surfaces. When the roll 08 further rotates in the sub-scanning direction SS and the latter half of the convex defect reaches the field of view of the sensor S as shown in FIG. 21C, the reflection direction of the slit inspection light L1 changes, and the convex defect is smaller than the normal surface. Reduce the sensor signal. In the case of a concave defect, FIG. 21D,
As can be seen from 21E, the sensor signal decreases from the normal value in the first half of the concave defect and increases in the latter half.

Therefore, the sensor signal is the sub-scanning direction SS.
On the other hand, convex defects appear in the positive and negative directions, and concave defects appear in the negative and positive directions. FIG. 22 shows a two-dimensional image in which a defect signal is extracted from the obtained sensor signal waveform by a threshold value in the positive direction and a threshold value in the negative direction. The horizontal axis represents the main scanning direction FS and the vertical axis represents the sub-scanning direction SS. A positive direction defect image (reception amount increase region) is obtained from the positive direction threshold value, and a negative direction defect image (reception amount decrease region) is obtained from the negative direction threshold value,
The uneven defect is a combination of defect images in the positive direction and the negative direction. As shown in FIG. 21, the line sensor S is provided downstream of the regular reflection direction of the slit inspection light L1 in the sub-scanning direction SS.
In the case of arranging, the convex defects appear in the order of the positive direction defect image (reception amount increase region) 026 and the negative direction defect image (reception amount decrease region) 027 (see FIG. 22A) with respect to the sub-scanning direction SS. , The concave defect is a negative direction defect image (reception amount decrease region) 027, the positive direction defect image (reception amount increase region) 026
Appear in the order of. In FIG. 21, when the sub-scanning direction SS is the reverse direction, the order of the sensor signal and the defect image is reversed.

The prior art (J04) has the following problems. (Problem of (J04)) In the surface layer defect detection device of (J04), the amount of light reflected from the slit inspection light boundary line is extracted by a positive / negative threshold value, and an image of different polarity obtained from the extracted signal is generated. We propose an inspection device that can distinguish concave and convex defects in order. However, an inspection object with a black surface and a low reflectance, such as a charging roll, has a low amount of light reflected from the slit inspection light boundary line portion, and the level of the sensor output signal of the normal surface that serves as a reference when extracting a defect is low. . Therefore, the contrast of the defect signal generated in the negative direction with respect to the normal surface is not sufficient, and it is difficult to extract the defect image in the negative direction by the threshold value in the negative direction. Therefore, it is difficult to detect defects on the surface having a black surface and a low reflectance by the method of (J04) without omission. In addition, (J0
In the method of 4), the concave or convex defect generated along the circumferential direction has the defect extending along the incident and reflecting directions of the inspection light. Is difficult to occur, and it is difficult to detect it and determine the unevenness.

In view of the above circumstances, the present invention provides the following (O01)
The content described in is the subject. (O01) To make it possible to discriminate the irregularities of the irregularities on the surface of the cylindrical body such as the photosensitive drum or the charging roll. (O02) To enable a good / bad determination according to the type of defect so that an accurate good / bad determination can be performed without re-inspection. (O03) It is also possible to determine the defect type for uneven defects on the surface of a cylindrical body such as a charging roll having a black surface and low reflectance, and uneven defects occurring in the circumferential direction.

[0017]

The present invention devised to solve the above problems will now be described. The elements of the present invention are to facilitate correspondence with the elements of the embodiments described later. Note that the reference numerals of the elements of the embodiments are enclosed in parentheses. Further, the reason why the present invention is described in association with the reference numerals of the embodiments described later is to facilitate understanding of the present invention and not to limit the scope of the present invention to the embodiments.

(First Invention) In order to solve the above problems,
The surface layer defect detection device (U) of the first invention of the present application is an object support device (U1) for rotating an object (R) having a cylindrical surface layer around its axis, and an object to be inspected. Slit inspection light (L) along the axial direction of the cylindrical surface layer of (R)
Slit inspection light irradiating device (4) for irradiating 1) and line sensor (S) for detecting the amount of reflected light from the surface layer of the inspected object (R) rotated by the inspected object supporting device (U1). And a surface layer defect detecting device (U) for detecting a defect in the surface layer depending on whether or not the detected light amount signal (Sa) of the line sensor (S) with respect to the reference light amount signal is provided with the following requirements. Characteristic, (Y01)
A spot inspection light irradiation device that irradiates the spot inspection light (L2) along the surface of the inspection object (R) from the vicinity of the end portion in the axial direction of the inspection object (R) so as to overlap the slit inspection light (L2) ( 5), (Y02) The line sensor (S) is arranged in the direction of regular reflection light of the slit inspection light (L1) from the surface of the inspection object (R),
(Y03) Defects (WS, H) in the surface layer of the inspection object (R)
O) exists, the unevenness state of the defect area, which is determined according to the order in which the detected light quantity of the reflected light from the defective area increases or decreases along the main scanning direction (FS), is associated with the increase or decrease of the detected light quantity. Data storage memory for judgment (2
2), (Y04) means for outputting a digital signal of the detected light amount signal of the line sensor (S), that is, digital signal output means (11), (Y05) the digital signal (15a) as defect determination image data. Image memory (17) to be stored, (Y06) An area where the image data (15a) stored in the image memory (17) is increased or decreased compared to the digital signal of the reference light amount signal is detected as a defective area. Defect area detection means (16), (Y07)
Increasing / decreasing order determining means (2) for detecting the order in which the amount of reflected light (Sa) detected from the defective area detected by the defective area detecting means (16) increases or decreases along the main scanning direction (FS).
3), (Y08) Defects detected by the defect area detection means (16) using the output signal of the increase / decrease order determination means (23) and the data stored in the determination data storage memory (22). Defect type determination means (24) for determining the unevenness state of the area.

(2nd invention) A 2nd invention of the present application is characterized in that the surface layer defect device of the 1st invention has the following requirements: (Y09) The digital signal output means (11) Is a defective digital signal (15) having a different value for the detected light amount signal of the line sensor (S) above a normal value within a predetermined range and below the normal value.
It must have the function of outputting as a).

(Embodiment 1) Embodiment 1 of the surface layer defect detection apparatus (U) of the present invention is characterized in that the following requirements are satisfied in the present invention: (Y001) Slit inspection light irradiation Device (4) is slit inspection light (L1)
Having a light source (6) that emits white diffused light as
(Y002) The spot inspection light irradiation device (5) has a halogen light source as a light source of the spot inspection light (L2),

(Embodiment 2) In the embodiment 2 of the surface layer defect detection apparatus (U) of the present invention, the defect type judging means (24) in the present invention or the embodiment 1 has the following requirements. (Y003) The digital signal output means (11) includes a positive direction threshold value memory (12) storing a positive direction threshold value (12a) and a negative direction threshold value (13).
a) a negative direction threshold value memory (13) storing the detected light amount signal (Sa) and digitizing the detected light amount signal (Sa) to A / D (analog / analog /
An A / D converter (14) that performs digital) conversion, and an output signal of the A / D converter (14) from each of the thresholds (1
2a, 13a) and comparison means (15) for comparison.

[0022]

Next, the operation of the present invention having the above features will be described. (Operation of First Invention) In the surface layer defect detecting apparatus (U) of the first invention of the present application having the above-mentioned characteristics, the inspected object supporting device (U1) has an inspected object ( Rotate R) about its axis. The inspection light irradiation device (3) irradiates the cylindrical surface layer of the inspection object (R) with slit inspection light (L1) along the axial direction thereof. The spot inspection light (L2) emitted from the end portion of the inspection object (R) is projected along the surface of the inspection object (R) substantially parallel to the central axis thereof. Then, the spot inspection light (L2) is applied to the inspection object (R).
The surface is superposed with the slit inspection light (L1). A line sensor (S) that detects the amount of light reflected from the surface layer of the inspection object (R) rotated by the inspection object supporting device (U1) is a slit inspection light (L1) from the inspection object (R) surface. Since the width of the field of view for receiving the specularly reflected light of) in the sub-scanning direction is wider than the width of the field of view of the light-dark boundary of the slit inspection light (L1), it is easy to adjust the field of light reception. Since the line sensor (S) is arranged in the direction of the specular reflection light of the slit inspection light (L1) from the surface of the inspection object (R), there are many defects in the surface layer. Receives the amount of reflected light. However, when a defect exists in the surface layer, the defect changes the direction of the reflected light of the slit inspection light (L1) from the surface of the inspection object (R), and the slit inspection light (L1) is arranged in the regular reflection direction. The amount of light (that is, the amount of detected light) reflected from the defect of the slit inspection light (L1) that should reach the line sensor (S) is reduced. Therefore, the line sensor (S) arranged so as to receive the specularly reflected light of the slit inspection light (L1) when the surface of the inspection object (R) has no unevenness defect is the surface of the inspection object (R). If there is a defect, the defect signal is generated in the negative direction as compared with the detection signal level of the normal surface.

The spot inspection light (L2) projected from the end to the center along the surface of the object (R) to be inspected is
When there is no defect, the scattered reflection light reflected toward the line sensor (S) is extremely small, but when there is a convex or concave defect, the scattered reflection light reflected toward the line sensor (S). Will increase. That is, of the spot inspection light (L1) emitted from the end of the inspection object (R),
The scattered reflected light from the surface of the object (R) to be inspected to the line sensor (S) increases at the inclined portion on the side closer to the emission position of the spot inspection light (L2) in the convex defect, and from the emission position in the concave defect. Increases at the distant slope. Therefore, the slit inspection light (L1) is applied to the surface of the inspection object (R).
And the spot inspection light (L2) are simultaneously projected to detect the amount of light reflected (Sa) from the surface of the inspection object (R) by the line sensor (S). A decreasing portion and an increasing portion of the detected light amount appear along the axial direction of the body (R). When the defect is a convex defect, the amount of light (Sa) detected by the line sensor (S) increases on the side closer to the emission position of the spot inspection light (L2) of the convex defect and decreases on the far side. . Further, when the defect is a concave defect, the amount of light (Sa) detected by the line sensor (S) is the spot inspection light (L) of the concave defect.
It decreases on the side closer to the emission position of 2) and increases on the side farther.

Therefore, after extracting the defect images in the positive and negative directions by the threshold value in the positive and negative directions and calculating the distance between the positive and negative defect images, the combination in which the defect images of different polarities are adjacent to each other is defined as the concavo-convex defect image. The convex defect and the concave defect can be discriminated from the order of polarities of the combined defect image (the order in which the defect image in the positive direction and the defect image in the negative direction are arranged along the axial direction of the inspection object (R)). Further, since the spot inspection light (L2) is projected from the end portion of the object (R) to be inspected toward the center portion, the defect in the circumferential direction (extends in the direction perpendicular to the optical path of the spot inspection light (L2)). (Streak-shaped uneven defects)
With respect to, the defect signal can be obtained, and the uneven defect can be discriminated.

The digital signal output means (11) outputs a digital signal (15a) of the detected light amount signal (Sa) of the line sensor (S). The digital signal (15a) is stored in the image memory (17) as image data (15a) for defect detection. Defect area detection means (16)
Detects a region where the image data (15a) stored in the image memory (17) increases or decreases as compared with the digital signal of the reference light amount signal as a defective region. The increasing / decreasing order determination means (23) is a defective area detection means (1
The order in which the amount of reflected light detected from the defective area detected in 6) increases or decreases along the main scanning direction (FS) is detected. When a defective area is detected by the defective area detecting means (16) (that is, the image data (15a) stored in the image memory (17) is increased or decreased as compared with the digital signal of the reference light amount signal. If there is a region), the defect type determination means (24) is the increase / decrease order determination means (23).
From the output signal (23a) and the data (22a) stored in the judgment data storage memory (22), the concave / convex state of the defective area detected by the defective area detecting means (16) is judged. That is, the defect type determining means (24)
Is the uneven state of the defect area (that is, the unevenness of the defect) according to the order in which the detected light amount increases and decreases along the main scanning direction.
To judge.

(Operation of the Second Invention) The digital signal output means (11) is different from the normal value above the normal value within which the detected light amount signal of the line sensor (S) falls within a predetermined range and below the normal value. The defective area detection means (16) outputs the image data (15a) stored in the image memory (17) as the reference light amount because it outputs as the defective digital signal (15a) of the value (“01”, “10”). It is possible to easily detect an area (that is, a defective area) that increases or decreases as compared with the digital signal of the signal.

(Operation of Embodiment 1) In the surface layer defect detection apparatus (U) of Embodiment 1 of the present invention, the slit inspection light irradiation device (4) irradiates white diffused light as inspection light (L1). . Further, the spot inspection light irradiation device (5)
Has a halogen light source, it is possible to emit high-intensity spot inspection light (L2). Inspection object (R)
When the surface is normal, even if high-intensity spot inspection light (L2) is used, very little spot inspection light (L2) is reflected by the inspection object (R) and enters the line sensor (S). However, if there is a convex or concave defect, the amount of light scattered and reflected by the defective portion and incident on the line sensor (S) increases. At this time, since the high-intensity spot inspection light (L2) emitted from the high-intensity halogen light source is used, a large amount of detectable scattered reflected light enters the line sensor (S).

(Operation of Embodiment 2) In the surface layer defect detecting device (U) of Embodiment 2 of the present invention, the A / D converter 14 of the digital signal output means (11) outputs the detected light amount signal as a digital signal. The digital signal is converted into the threshold value (12) stored in the positive threshold memory (12) and the negative threshold memory (13) by the comparison means 15, respectively.
The defective digital signal is output as compared with a) and (13a).

[0029]

EXAMPLES Examples of the present invention will now be described with reference to the drawings, but the present invention is not limited to the following examples. FIG. 1 is an overall schematic perspective view of an embodiment of a surface layer defect detecting device of the present invention. FIG. 2 is a functional block diagram of the signal processing portion U2 of the embodiment. FIG. 3 is a flowchart of the signal processing of the signal processing portion U2 shown in FIG. FIG. 4 is an explanatory diagram of a method of determining a threshold level when detecting a defect signal in the same embodiment.

In FIG. 1, the whole surface layer defect detecting apparatus for inspecting the surface of the object R to be inspected having a cylindrical surface layer is indicated by U. The surface layer defect detection device U has a rotating main shaft 1 and a tailstock shaft 2 that sandwich the shaft of the inspection object R from both ends in the front-rear direction (X-axis direction). The rotary main shaft 1 is rotationally driven by a motor (not shown), and the tailstock shaft 2 is rotatably supported by a bearing (not shown) movable in the axial direction. An element-to-be-inspected supporting device U1 is constituted by the elements indicated by the reference numerals 1 and 2.

In FIG. 1, the device under test support U1
The inspection light irradiation device 3 for irradiating the cylindrical surface layer of the inspection object R supported by the inspection light along the axial direction thereof has a slit inspection light irradiation device 4 and a spot inspection light irradiation device 5. . The slit inspection light irradiation device 4 is composed of a fluorescent lamp 6 as a light source and a light shielding case 7 surrounding the fluorescent lamp 6. The light shielding case 7 is formed with a slit 7a for projecting light. The slit inspection light L1 emitted from the fluorescent lamp (that is, the light source) 6 that emits white diffused light and passed through the slit 7a is applied to the surface of the inspection object R along the axial direction (X direction). In FIG. 1, a spot inspection light irradiation device 5 includes a point light source device 8 such as a halogen light source, a light guide 9 formed of an optical fiber bundle that guides light emitted from the point light source device 8, the roll to be inspected (having a cylindrical surface layer. The object to be inspected) R is constituted by a spot inspection light emitter 10 and the like.

The spot inspection light emitter 10 has a condenser lens that collects the light emitted from the tip of the light guide 9 and emits it toward the surface of the object R to be inspected. The spot inspection light (inspection light that linearly irradiates the surface of the inspection object R) L2 is emitted so as to be superimposed on the slit inspection light L1 of the surface (inspection surface) of the inspection object R. The optical axis of the spot inspection light L2 is a value close to an angle (projection angle) θ formed by the central axis of the inspection object R to approximately 0 (that is, the optical axis of the spot inspection light L2 and the inspection target roll). The surface (inspection surface) of the object R to be inspected is irradiated as a value in which the central axis is approximately parallel. Further, it is preferable that the distance d between the optical axis of the spot inspection light L2 and the inspection surface of the object R to be inspected is close to each other. From experiments, it is preferable that the angle θ is 0 to 5 degrees and the distance d is about 10 mm.

The line sensor S has the slit inspection light L.
The light receiving visual field was adjusted to the center of the irradiation area of the slit inspection light L1 and the spot inspection light L2 along the axial direction (main scanning direction) FS of the inspection object R so as to receive 1 specularly reflected light. It has a reduction optical system and a large number of photoelectric conversion elements arranged in parallel with the main scanning direction FS. The object to be inspected R is placed on the photoelectric conversion element of the line sensor (light receiving sensor) S.
In a state where the reflected light from the surface (inspection surface) is converged, scanning is performed by the line sensor S while rotating the inspected object R to detect the detection signal of the amount of reflected light from the surface (inspection surface) of the inspected object R. obtain.

Next, the signal processing portion U2 of this embodiment will be described with reference to FIG. The signal processing portion U2 has a digital signal output means 11 to which the detected light amount signal Sa output from the line sensor S is input. The digital signal output means 11 includes a positive direction threshold value memory 12 storing a positive direction threshold value 12a, a negative direction threshold value memory 13 storing a negative direction threshold value 13a, and the detected light amount signal Sa in A / D.
A / D converter 14 for (analog / digital) conversion
And comparison means 15. The comparison means 15 is the A
The digital signal "Sa" of the detected light amount signal Sa output from the / D converter 14 is compared with the positive and negative threshold values 12a and 13a to output a 2-bit digital signal (that is, image data for defect determination) 15a.

When the object R to be inspected is, for example, a fixing roll, the thresholds 12a and 13a have a height H <when the defect is a convex defect, as can be seen from the defect limit standard shown in FIG.
In the case of a concave defect of 5 μm, the defect is determined so that a defect outside the range of depth D <8 μm is detected. Next, the threshold 12
The method of defining a and 13a will be described. For example, for the threshold value 12a of the convex defect, the signal level of the defective portion is measured using a sample having a convex defect whose height H = 2 μm, 5 μm, and 10 μm is known. The signal level in this case is as shown in FIG. Since the height of the signal level is proportional to the height H of the convex defect, the threshold 12a is determined to the level shown in FIG. 4 from the signal level corresponding to the limit standard of the height H = 5 μm.
In addition, the threshold value 13a of the concave defect is the depth D = 5 μm, 8 μ
m and 11 μm are determined in the same manner as the above convex defect using a sample having a known concave defect.

The digital signal output means 11 has a unit 12a.
>“Sa”> 13a, a 2-bit signal “00” (that is, the surface layer of the object R to be inspected is normal)
A digital signal of the reference light amount) is output as image data 15a for defect determination, and when "Sa"> 12a, a 2-bit signal "0" indicating that the detected light amount exceeds the normal value.
1 "is output as the image data 15a for defect determination.
When "Sa"<13a, a 2-bit signal "10" indicating that the detected light amount is equal to or less than the normal value is output as the image data 15a for defect determination.

The signal processing portion U2 has a defective area detecting means 16, and the defective area detecting means 16 has an image memory 17. The defect area detecting means 16 surface develops the 2-bit image data 15a output from the digital signal outputting means 11 and stores it in the image memory 17 as image data 15a for defect determination. Also,
The defective area detecting means 16 detects, as a defective area, an area in which the image data 15a stored in the image memory 17 increases or decreases as compared with the digital signal of the reference light amount signal. That is, the defect area detecting means 16 calculates the type of unevenness, the center position, the area, and the perimeter of the defect image from the image data 15a of the image memory 17, and the information obtained by this calculation is used as the defect image (the "Sa" above). > 12a, "Sa"<13a
(Collection part of data of), that is, a function of outputting it as defect image information 16a.

Further, the signal processing portion U2 has a judgment information output means 21. This determination information output means 21
Has a determination data storage memory 22. The determination data storage memory 22 stores determination data 22a according to the type of the inspection object R. As the judgment data 22a, there is unevenness judgment data for judging whether the defect is an unevenness, and for area judgment for judging that the size (area) of the defect exceeds an allowable value. Data and the like are stored.

In the unevenness determination data, a defective area of "Sa"> 12a appears first along the main scanning direction, and then "Sa".
This is data for determining the unevenness of the defect depending on whether the defect area of <13a appears or vice versa. Although details will be described later, for example, when there is a convex defect SW, “Sa” along the main scanning direction depends on which end of the both ends of the inspected object R in the spot inspection light emitter 10 in the axial direction. >
The order in which the defect area of 12a and the defect area of "Sa"<13a appear is different. Therefore, the spot inspection light emitting device 1
0 and the position of the line sensor S are determined in an actual inspection state, and in that state, a defect area of "Sa"> 12a and "Sa"<13a along the main scanning direction are determined.
The order of appearance of the defective areas and the defective areas will be investigated.
The order in which the defect areas appear and the type of defect (convex defect or concave defect) corresponding thereto are stored in the determination data storage memory as unevenness determination data.

For example, when the object R to be inspected is a fixing roll, the area determination data is such that the diameter (size) of the convex defect A <0.4 mm and the diameter (size of the concave defect are as shown in FIG. A) Diameter (size) outside the range of A <2 mm
Data that can detect the defect of A, that is, A = 0.
The data corresponds to 4 mm and A = 2 mm. Actual data for determining the size of the diameter A is stored by the number of pixels of the line sensor S. The defect determination data may be stored as the number of pixels representing the area of the defect instead of storing the number of pixels representing the size of the diameter A of the defect.

The judgment information output means 21 has an increase / decrease order judgment means 23 for detecting the order in which the amount of reflected light from the defective area detected by the defective area detecting means 16 increases or decreases along the main scanning direction FS. There is. Further, the determination information output means 21 outputs the increase / decrease order determination signal 23a output from the increase / decrease order determination means 23 to the determination data storage memory 22.
The judgment data 22a is used to judge the unevenness of the defect, and the good or bad of the inspection object R is judged.
It has a defect type judging means 24 which outputs a pass / fail judgment signal 21a.

Next, referring to FIGS. 5 to 12, the principle of discriminating uneven defects according to this embodiment will be described. 5 to 8 are explanatory views of changes in the amount of reflected light of the slit inspection light L1 or the spot inspection light L2 from the surface of the inspection object R, and FIGS. 9 to 12 show the slit inspection light L1 and the spot inspection light L2 simultaneously. It is explanatory drawing of the change of the reflected light amount from the to-be-inspected object R surface at the time of using. Next, FIGS. 5 to 8 will be described first. FIG. 5 is an explanatory view of the operation of the embodiment and shows a state in which the surface layer of the inspection object R has no defects. FIG. 6 is an operation explanatory view of the same embodiment when there is a convex defect in the surface layer of the object to be inspected, and FIG. 6A is a front half portion of the convex defect (half of the front half in the rotational direction of the cylindrical object R to be inspected). ) S
6B shows a state in which the detected reflected light amount of the slit inspection light L1 decreases in W1, FIG. 6B shows a state in which the detected reflected light amount of the slit inspection light L1 decreases in the latter half portion SW2 of the convex defect, and FIG. 6C shows a position where the convex defect exists. With slit inspection light L1
It shows that the amount S1a of the reflected light detected by is decreased. Figure 7
7A is an operation explanatory view of the same embodiment when the surface layer of the inspection object R has a concave defect, and FIG. 7A shows a front half portion of the concave defect (half on the front side in the rotational direction of the cylindrical inspection object R) HO1. 7B shows the state in which the detected reflected light amount S1a of the slit inspection light L1 decreases, FIG. 7B shows the state in which the detected reflected light amount S1a of the slit inspection light L1 decreases in the latter half HO2 of the concave defect, and FIG. 7C shows the concave defect. At the position, slit inspection light L1
It shows that the amount S1a of the reflected light detected by is decreased. FIG.
Is a spot inspection light emitter 1 when there is a convex or concave defect in the surface layer of the inspection object R in the operation explanatory view of the embodiment.
FIG. 7 is a diagram showing that the amount of reflected light of spot inspection light L2 from the slope facing 0 is increased.

As shown in FIG. 5, the inspection object R has an arrow SS.
Direction (sub-scanning direction), the line sensor S
Are arranged in the direction of the regular reflection light of the slit inspection light L1 emitted from the slit inspection light irradiator 4 which is regularly reflected by the normal surface (the surface of the portion having no defect) of the inspection object R.
The slit inspection light L1 emitted from the slit inspection light irradiation device 4 to the normal surface is specularly reflected and is incident on the line sensor S. In this case, a high level of constant slit inspection light reflected light is incident on the line sensor S. On the other hand, as shown in FIG. 8, most of the spot inspection light L2 emitted from the spot inspection light emitter 10 is reflected in the regular reflection direction on the normal surface of the inspection object R, and the line sensor S has a low level. Spot inspection light Reflected light enters. The total sum of the reflected lights of the slit inspection light L1 and the spot inspection light L2 from the normal surface of the inspection object R is constant.

Next, the reflected light of the slit inspection light L1 when the convex defect SW exists will be described with reference to FIG. In FIG. 6A, when the right side portion (downstream side portion in the sub scanning direction) SW1 of the convex defect SW on the surface of the inspection object R enters the irradiation area of the slit inspection light L1, the projected slit inspection light L1 is scattered by SW1. Alternatively, since the light is deflected and not reflected in the regular reflection direction, the amount of light incident on the line sensor S arranged in the regular reflection direction is reduced, and a defect signal appears in the negative direction as compared with the normal surface signal. In FIG. 6B, the convex defect S on the surface of the inspection object R
When the left side portion of W (upstream side portion in the sub-scanning direction) SW2 enters the irradiation area of the slit inspection light L1, the projected slit inspection light L1 is scattered or deflected by SW2 and is not reflected in the regular reflection direction. The amount of light incident on the line sensor S arranged in the reflection direction decreases, and a defect signal appears in the negative direction compared to the normal surface signal. In FIG. 6C, the slit inspection light (inspection light) L1 emitted from the slit inspection light irradiation device 4 and irradiating the surface of the inspection object R is reflected in the direction deviated from the regular reflection direction when the convex defect SW is present. , The amount of light incident on the line sensor S decreases. That is, the reflected light amount S1a of the slit inspection light L1 detected by the line sensor S from the convex defect SW is always reduced as compared with the detected reflected light amount from the normal surface.

Next, the reflected light of the slit inspection light L1 when the concave defect HO exists will be described with reference to FIG. In FIG. 7A, when the right side portion (downstream side portion in the sub-scanning direction) HO1 of the concave defect HO on the surface of the inspection object R enters the irradiation area of the slit inspection light L1, the projected slit inspection light L1 is scattered by HO1. Alternatively, since the light is deflected and not reflected in the regular reflection direction, the amount of light incident on the line sensor S arranged in the regular reflection direction is reduced, and a defect signal appears in the negative direction as compared with the normal surface signal. In FIG. 7B, the concave defect H on the surface of the inspection object R
Even when HO2 on the left side of O (upstream side in the sub-scanning direction) enters the irradiation area of the slit inspection light L1, the amount of incident light on the line sensor S arranged in the regular reflection direction is reduced for the same reason as described above. However, the defect signal appears in the negative direction as compared with the normal surface signal. In FIG. 7C, slit inspection light irradiation device 4
The slit inspection light L1 emitted from the and irradiating the surface of the inspection object R is reflected in a direction deviated from the regular reflection direction when the concave defect HO is present, so that the amount of light incident on the line sensor S is reduced. That is, the amount of reflected light S1a of the slit inspection light L1 detected by the line sensor S from the concave defect HO.
Is always reduced compared to the amount of reflected light detected from the normal surface.

Next, referring to FIG. 8, the amount of spot inspection light reflected by the line sensor S when the spot inspection light L2 is reflected by the convex defect SW or the concave defect HO on the surface of the object R to be inspected will be described. The spot inspection light emitter 10 is arranged on the left end side of FIG.
The case of irradiating the surface of the inspection object R from the left side of FIG. When the angle θ formed by the spot inspection light L2 with the normal surface of the inspection object R is incident at a small angle of 0 <θ ≦ 5 °, the spot inspection light L2 is specularly reflected and travels along the surface of the inspection object R. Go in the direction. Therefore, the reflected light of the spot inspection light L2 from the normal surface of the inspection object R hardly enters the line sensor S. When the spot inspection light L2 is incident on the left side portion (the left side portion in the main scanning direction FS in FIG. 8) of the convex defect SW on the surface of the inspection object R, the scattered reflection light toward the line sensor S increases and the line sensor S increases. In the detected reflected light amount S2a of the spot inspection light L2 detected by, a signal in the positive direction (a detected light amount increase signal) appears as compared with the normal surface signal. However, in the spot inspection light L2, the scattered reflection light toward the line sensor S does not increase in the right side portion of the convex defect SW (right side portion in the main scanning direction FS in FIG. 8). Further, when the spot inspection light L2 is incident on the right side portion of the concave defect HO on the surface of the inspection object R (right side portion in the main scanning direction FS in FIG. 8), the scattered reflected light toward the line sensor S increases and the line Regarding the detected reflected light amount S2a of the spot inspection light L2 detected by the sensor S, a signal in the positive direction (a detected light amount increase signal) appears as compared with the normal surface signal. However, in the spot inspection light L2, the scattered reflection light toward the line sensor S does not increase in the left side portion of the concave defect HO (the left side portion in the main scanning direction FS in FIG. 8).

As described above, according to FIGS. 5 to 8, the slit L1
The change in the amount of reflected light detected from the surface of the object R to be inspected and the change in the amount of reflected light detected from the surface of the object R to be inspected L2 have been described. Next, referring to FIGS. When the inspection light L2 is used simultaneously, the amount of reflected light detected by the line sensor S Sa (S1a + S2
The changes in a) will be explained. FIG. 9 is an operation explanatory view of the same embodiment when there is a convex defect in the surface layer of the inspection object R,
FIG. 9A is a diagram showing a positional relationship between the slit inspection light L1 and the spot inspection light L2 irradiation device and the line sensor S with respect to the convex defect, and FIG. 9B shows that the detected reflected light amount S1a of the slit inspection light L1 decreases due to the convex defect. 9C shows that the detected reflected light amount S2a of the spot inspection light L2 from the slope portion near the spot inspection light emitter 10 of the convex defect increases, and FIG. 9D shows the total amount Sa of the detected light by the line sensor S Sa. FIG. 6 is a diagram showing that (S1a + S2a) increases on the side closer to the spot inspection light emitter 10 and decreases on the far side due to a convex defect.

FIG. 10 is an explanatory view of the operation of the same embodiment when the surface layer of the inspection object R has a concave defect, and FIG. 10A is a slit inspection light L1 and a spot inspection light L2 for the concave defect.
10B is a diagram showing the positional relationship between the irradiation device and the line sensor S. FIG. 10B shows that the detected reflected light amount S1a of the slit inspection light L1 decreases due to the concave defect, and FIG. 10C shows the spot inspection light emitter for the concave defect. 10 shows that the detected reflected light amount S2a of the spot inspection light L2 from the distant slope portion increases, and FIG. 10D shows that the total sum Sa (S1a + S2a) of the detected light amounts by the line sensor S is a spot inspection light emitter 10 due to a concave defect. It is a figure which shows that it decreases on the side closer to and increases on the side far away. FIG. 11 is a diagram showing that the amount of reflected light due to a convex defect increases on the side closer to the spot inspection light emitter 10 along the main scanning direction FS and decreases on the side farther. FIG. 12 is a diagram showing that the amount of reflected light due to the concave defect decreases along the main scanning direction FS on the side closer to the spot inspection light emitter 10 and increases on the side farther.

As shown in FIG. 9A, the inspection object R is irradiated with the slit inspection light L1, the line sensor S is arranged at a position for receiving the specularly reflected light, and the slit inspection light on the inspection object R is provided. Consider a case where the spot inspection light L2 is superposed on the L1 from the left side of FIG. 9A. In this case, the convex defect S
When W is present, the amount of light detected by the line sensor S is represented by the amount of reflected light S1a detected by the slit inspection light L1 in FIG. 9B and the amount of reflected light S2a detected by the spot inspection light L2 in FIG. 9C. The total sum Sa (S1a + S2a) of the detected reflected light amounts of the slit inspection light L1 and the spot inspection light L2 is shown in FIG. 9D.
Is represented by. In FIG. 9D, if there is a convex defect WS on the surface of the object R to be inspected, a positive direction defect signal (from the side closer to the spot inspection light emitter 10 (the light source side of the spot inspection light L2) is sequentially arranged along the main scanning direction FS. A value larger than the threshold 12a) and a negative direction defect signal (value smaller than the threshold 13a) appear. That is, the defects in which the positive direction defect signal and the negative direction defect signal appear in order from the side closer to the spot inspection light emitter 10 (the light source side of the spot inspection light L2) along the main scanning direction FS are convex defects. I understand.

Digital signal output means 11 shown in FIG.
As described above, the detection signal Sa of the line sensor S is
(= S1a + S2a) is compared with the forward threshold 12a,
When "Sa"> 12a, a 2-bit signal "01" indicating that the detected light amount exceeds the normal value is output as the defect determination image data 15a (see FIG. 2). In addition, "S
When "a"<13a, a 2-bit signal "10" indicating that the detected light amount is equal to or less than the normal value is output as the image data 15a for defect determination. When the detection signal Sa of the line sensor S is 13a ≦ “Sa” ≦ 12a, the 2-bit signal “00” is output as the image data 15a for defect determination.

As shown in FIG. 10A, when there is a concave defect HO on the surface of the object R to be inspected, the detected light amount of the line sensor S is the reflected light amount S1a of the slit inspection light L1 shown in FIG. 10B. The detected reflected light amount S2a of L2 is shown in FIG. 10C.
Is represented by. Then, the sum Sa of the detected reflected light amounts of the slit inspection light L1 and the spot inspection light L2 (= S1a + S2a)
Is represented in FIG. 10D. From FIG. 10D, the main scanning direction F
It can be seen that the defects in which the negative defect signal and the positive defect signal appear in order from the side closer to the spot inspection light emitter 10 (the emission side of the spot inspection light L2) along S are concave defects.

When the image data 15a (see FIG. 2) is surface-developed, as shown in FIG. 11, areas of the defect signal "01" are sequentially arranged from the light source side of the spot inspection light L2 along the main scanning direction FS. 26 and area 27 of the defect signal “10”
The part where is shown is a convex defect. In the surface-developed image data 15a, as shown in FIG.
A portion along which the region 27 of the defect signal "10" and the region 26 of the defect signal "01" appear in sequence from the light source side of the spot inspection light L2 along S is a concave defect.

(Operation of Embodiment) In FIG. 1, when the inspection object R is to be inspected, the inspection object R is moved from both ends in the axial direction by the rotating main shaft 1 and tailstock shaft 2 of the inspection object supporting device U1. Hold it. Then, the inspection subject R is rotated by rotating the rotating main shaft 1. The line sensor S detects the combined reflected light of the slit inspection light L1 and the spot inspection light L2 with respect to the inspection object R. The line sensor S scans in the main scanning direction FS (see FIG. 1) and, for example, 500
An analog signal train for 0 pixels is output as the sensor signal Sa. Since the inspection object R rotates in the sub-scanning direction SS,
The entire surface of the roll is inspected by the line sensor S extending in the main scanning direction (X-axis direction).

In FIG. 2, digital signal output means 11
After the sensor signal Sa is A / D converted by the above, the threshold memory 12 set in the positive direction and the threshold memory 1 set in the negative direction with respect to the signal level of the normal surface of the inspection object R.
3 threshold values 12a, 13a. And 12a>
When “Sa”> 13a, a 2-bit signal “00” indicating that the surface layer of the inspection object R is normal is output,
When "Sa"> 12a, a 2-bit signal "01" indicating that the detected light amount exceeds the normal value is output.
When "Sa"<13a, a 2-bit signal "10" indicating that the detected light amount is equal to or less than the normal value is output as the image data 15a for defect determination. Detected image data 15a
Is surface-developed in the sub-scanning direction by the defect area detecting means 16 and stored in the image memory 17 as image data 15a. The defect area detecting means 16 calculates the type of unevenness, the center position, the area, and the perimeter of the defect image from the image data 15a, and outputs the defect image information. The determination information output means 21 stores the calculated defect image information 16a in the determination data storage memory 22.
The non-defective / defective determination signal 21a is compared with the unevenness determination data and area determination data (defect limit standard)
Is output.

Next, the signal processing portion U2 from the defect image in which the sensor signal is surface-developed using the flowchart of FIG.
The operation of will be described. In step ST1, the distance K between the center positions of the defect image 26 in the positive direction and the defect image 27 in the negative direction is calculated. That is, of the defect images 26 and 27, the distance between the center positions is calculated for the one where the position in the sub-scanning direction overlaps, and the one where the distance between the center positions in the main scanning direction is the shortest. In step ST2, a pair of adjacent positions where the distance K is equal to or less than a constant value (for example, K = 1 mm) is detected as an uneven defect image. In step ST3, a positive direction image (image in which the detected light amount is increased) and a negative direction image (image in which the detected light amount is decreased) of the detected uneven defect image are detected.
The coordinates of the center position of in the main scanning direction FS are compared. That is, it is determined whether the image in the positive direction appears first and then the image in the negative direction appears along the main scanning direction FS. In steps ST4 and ST5, it is determined from the comparison result whether the defect is a concave defect or a convex defect. In the apparatus of the present embodiment, when a defect image in the negative direction appears subsequently to a defect image in the positive direction, it is a convex defect, and the opposite is a concave defect.
If YES in step 3, it is determined to be a convex defect in step ST4, and if NO, it is determined to be a concave defect in step ST5.

(Modifications) Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, but is within the scope of the gist of the present invention described in the claims. Thus, various changes can be made. A modified embodiment of the present invention is illustrated below. (H01) In the above embodiment, instead of the digital signal output means 11 which outputs the digital signal 15a according to whether the detected light amount signal of the line sensor S is a normal value within a predetermined range, the line sensor S It is possible to configure by a digital signal output means that simply converts the detected light amount signal into a digital signal and outputs it. In this case, the defective area detection unit 16 may have a function of determining which range of the digital signal is a normal value or not. (H02) The present invention is not limited to the photoconductor drum, the fixing roll, and the charging roll, and inspects an inspected object in which a film is formed on the surface of a cylindrical substrate and the surface layer has a mirror surface or a slight mirror surface. Etc. can also be applied. (H03) The digital signal output means can convert the sensor signal Sa into a digital signal and then compare the sensor signal Sa with the positive threshold value and the negative threshold value. However, the threshold value in the state of the analog signal before the digital signal conversion is performed. It is also possible to convert it into a digital signal after comparing with. (H04) A fluorescent lamp was used as the light source of the slit inspection light and a halogen light source was used as the light source of the spot inspection light. However, the light source of the slit inspection light is not limited to the fluorescent lamp, and the halogen light source is used as the slit inspection light by the fiber bundle and the perfect diffusion lens. It is possible to use a light source that emits white diffused light by adding a light source, and the light source for spot inspection light is not limited to a halogen light source. It is possible to use a light beam.

[0057]

The effects of the surface layer defect detecting device of the present invention described above can achieve the following effects. (E01) Concavity and convexity of a defect can be determined for a concavo-convex defect on the surface of a cylindrical body such as a photosensitive drum or a charging roll. (E02) The quality of the product can be determined according to the type of defect, and since the false information of the quality determination is deleted, accurate quality determination can be performed without re-inspection. (E03) It is possible to discriminate an uneven defect that occurs in the inspected object whose surface to be inspected is almost black and has a low reflectance, or an uneven defect that occurs in the circumferential direction.

[Brief description of drawings]

FIG. 1 is an overall schematic perspective view of an embodiment of a surface layer defect detection device of the present invention.

2 is a functional block diagram of a signal processing portion of FIG. 2 embodiment.

3 is a flowchart of signal processing of the signal processing portion shown in FIG.

FIG. 4 is an explanatory diagram of a method of determining a threshold level when detecting a defect signal in the same embodiment.

FIG. 5 is an explanatory view of the operation of the embodiment, showing a state in which there is no defect in the surface layer of the inspection object.

FIG. 6 is an operation explanatory view of the same embodiment when the surface layer of the inspection object has a convex defect, and FIG. 6A shows the first half of the convex defect (the front side in the rotation direction of the inspection object R). Half) shows a state in which the detected reflected light amount of the slit inspection light L1 decreases, FIG. 6B shows a state in which the detected reflected light amount of the slit inspection light L1 decreases in the latter half of the convex defect, and FIG. 6C shows a case where the convex defect exists. Shows that the detected reflected light amount of the slit inspection light L1 decreases.

FIG. 7 is an explanatory view of the operation of the same embodiment when the surface layer of the object to be inspected has a concave defect, and FIG. 7A is a front half portion of the concave defect (half on the front side in the rotational direction of the object to be inspected R). ) Shows a state in which the detected reflected light amount of the slit inspection light L1 decreases, FIG. 7B shows a state in which the detected reflected light amount of the slit inspection light L1 decreases in the latter half of the concave defect, and FIG. 7C shows a case where the concave defect exists. Indicates that the amount of reflected light detected by the slit inspection light L1 decreases.

FIG. 8 is an explanatory view of the operation of the embodiment, in which the spot inspection light L from the surface facing the spot inspection light emitter 10 side when the surface layer of the inspection object has a convex or concave defect.
FIG. 7 is a diagram showing that the amount of reflected light of No. 2 increases.

FIG. 9 is an operation explanatory view of the same embodiment when the surface layer of the inspection object R has a convex defect, and FIG. 9A is an irradiation device of the slit inspection light L1 and the spot inspection light L2 for the convex defect. FIG. 6 is a diagram showing a positional relationship between the line sensor S and
FIG. 9B shows that the detected reflected light amount of the slit inspection light L1 decreases due to the convex defect, and FIG. 9C shows the spot inspection light L from the slope portion near the spot inspection light emitter of the convex defect.
2 shows that the amount of reflected light detected increases, and FIG. 9D is a diagram showing that the total amount of light detected by the line sensor S increases on the side closer to the spot inspection light emitter and decreases on the far side due to the convex defect. .

FIG. 10 is an operation explanatory view of the same embodiment when the surface layer of the inspection object R has a concave defect, and FIG. 10A is a slit inspection light L1 and a spot inspection light L2 for the concave defect.
10B is a diagram showing the positional relationship between the irradiation device and the line sensor S, FIG. 10B shows that the amount of reflected light detected by the slit inspection light L1 decreases due to the concave defect, and FIG. 10C shows the spot inspection light emitter for the concave defect. FIG. 10D shows that the detected reflected light amount of the spot inspection light L2 from the distant slope portion increases, and the total amount of detected light by the line sensor S decreases on the side closer to the spot inspection light emitter due to the concave defect,
It is a figure which shows that it increases on the far side.

FIG. 11 is a diagram showing that the amount of light reflected by a convex defect increases along the main scanning direction on the side closer to the spot inspection light emitter and decreases on the side farther from the spot inspection light emitter.

FIG. 12 is a diagram showing that the amount of reflected light due to a concave defect decreases along the main scanning direction on the side closer to the spot inspection light emitter and increases on the far side.

FIG. 13 is a diagram for explaining that even a defect having the same size has a different effect on fixing between a convex defect and a concave defect.

FIG. 14 is a diagram showing a table of roll component defect limit standard examples.

FIG. 15 is a schematic explanatory view for explaining a conventional surface layer defect detection device.

16 is an explanatory view of the operation of the prior art shown in FIG. 15, FIG. 16A is an explanatory view of the operation in the absence of a defect, FIG. 16B is an explanatory view of the operation when there is a defect, and FIG. 16C is a circumferential direction. It is an explanatory view of the operation when there is a streak-like defect along the.

FIG. 17 is an explanatory diagram of another conventional technique, which is an explanatory diagram of what can detect streak defects along the circumferential direction.

FIG. 18 is a schematic explanatory view for explaining a conventional surface layer defect detecting device for an automobile body.

FIG. 19 is a schematic explanatory diagram for explaining a conventional surface layer defect detecting device for an automobile body.

FIG. 20 is an operation explanatory view of the conventional surface layer defect detecting apparatus shown in FIG.

FIG. 21 is an explanatory view of another conventional surface device defect detection apparatus, which is an explanatory view of what can determine the unevenness of a defect, FIG. 21A is a view showing a state without a defect, and FIG. 21B is a convex defect. FIG. 21C is a diagram showing the amount of reflected light detected in the first half of the sub-scanning direction, FIG. 21C is a diagram showing the amount of reflected light detected in the second half of the convex defect in the sub-scanning direction, and FIG. 21D is a diagram showing the amount of reflected light detected in the first half of the concave defect in the sub-scanning direction. FIG. 21E is a diagram showing the amount of reflected light detected in the second half of the concave defect in the sub-scanning direction.

FIG. 22 is a diagram showing increase / decrease in the amount of detected reflected light from a convex or concave defect, and FIG. 22A is a diagram showing that the amount of reflected light due to a convex defect increases along the sub-scanning direction and then decreases. 22B is a diagram showing that the amount of reflected light due to a concave defect decreases along the sub-scanning direction and then increases.

[Explanation of symbols]

L1 ... Slit inspection light, L2 ... Spot inspection light, R ... Inspected object, S ... Line sensor, U ... Surface layer defect detection device, U
1 ... Device to be inspected, U2 ... Signal processing part, 3 ... Inspection light irradiation device, 4 ... Slit inspection light irradiation device, 5 ... Spot inspection light irradiation device, 11 ... Digital signal output means (digital signal output means), 15a ... Digital signal (image data), 16 ... Defect area detecting means, 17 ... Image memory, 2
2 ... Judgment data storage memory, 23 ... Increasing / decreasing order judging means, 24 ... Defect type judging means,

Claims (2)

[Claims] 1. A device under test supporting device for rotating a device under test having a cylindrical surface layer around its axis, and a cylindrical surface layer of the device under test is irradiated with slit inspection light along its axial direction. A slit inspection light irradiating device and a line sensor for detecting the amount of light reflected from the surface layer of the object to be inspected rotated by the device to be inspected are provided, and the amount of light detected by the line sensor relative to the reference light amount signal A surface layer defect detection apparatus for detecting defects in the surface layer according to claim 1, wherein the surface layer defect detection apparatus has the following requirements: (Y01) From the vicinity of the axial end portion of the inspection object A spot inspection light irradiation device that emits spot inspection light so as to overlap the slit inspection light along a surface, (Y02) The line sensor is the slit inspection light on the surface of the inspection object. And (Y03) in the order of increasing or decreasing the detected light amount of the reflected light from the defective area when there is a defect in the surface layer to be inspected. A determination data storage memory that stores the unevenness state of the defective area determined according to the increase or decrease of the detected light amount, (Y04) means for outputting a digital signal of the detected light amount signal of the line sensor, that is, a digital signal Outputting means, (Y05) Image memory for storing the digital signal as defect determination image data, (Y06) The image data stored in the image memory is increased or decreased in comparison with the digital signal of the reference light amount signal. Defective area detecting means for detecting an area as a defective area, (Y07) The detected light amount of the inspection light reflected from the defective area detected by the defective area detecting means is in the main scanning direction. Decrease the order determination means for detecting the order of increasing or decreasing I, (Y
08) Defect type determination means for determining the concavo-convex state of the defect area detected by the defect area detection means using the output signal of the increase / decrease order determination means and the data stored in the determination data storage memory. 2. The surface device defect detection device according to claim 1, wherein the digital signal output means has a normal light detection signal of the line sensor within a predetermined range. It shall have a function to output values above the value and below the normal value as defective digital signals with different values.