JPH06118007A - Method and device for inspecting defect on cylinder surface - Google Patents

Abstract

PURPOSE:To automatically inspect surface defects such as very gentle irregularities on the low-glossiness surface of a cylinder. CONSTITUTION:A slit light image 10 which has repeated patterns of a bright portion 11, a dark portion 12 and a shade portion 13 between the bright portion 11 and the dark portion 12 on the low-glossiness surface 2 in the axial direction of a cylinder 1 is formed to detect reflected light actualized due to surface defects at the shade portion 13 of the formed slit light image 10. The repeated patterns of the slit light image are moved to the axial direction and the cylinder is rotated so that the surface defects all over the surface of the cylinder 1 is automatically detected.

Description

Detailed Description of the Invention

[0001]

The present invention relates to surface defect inspection,
In particular, the present invention relates to a surface defect inspection method for a roll-shaped part such as a heat roll used for a fixing device in an image output device such as an electrostatic copying machine or a laser printer, and the device therefor.

[0002]

2. Description of the Related Art Many of fixing devices used in image output devices of electrostatic photocopiers and laser printers develop an electrostatic latent image formed on a photoconductor with toner and then develop the electrostatic latent image. A so-called heat roll system is adopted in which the toner is melted by fixing the image on the paper by transferring the paper onto the paper and passing the paper on which the toner image is transferred between two heated rolls.

In this type of heat roll, a surface layer such as fluororesin or fluororubber is applied through an adhesive to the surface of a raw tube (cylindrical base) made of aluminum or the like containing a heat source such as a lamp, and then the It is manufactured through a process of polishing the surface to finish a smooth curved surface. In this manufacturing process, coating unevenness of the surface layer in the coating process of the surface of the cylindrical body and contamination of foreign matter, or defects such as dents and scratches may occur on the surface during handling in the process of incorporating into the fixing device. is there.

FIG. 5 is an explanatory view of surface defects of a cylindrical body having a low gloss surface such as a heat roll, and 40 is a cylindrical body,
Reference numeral 41 schematically shows defects attached in the axial direction of the surface, and 42 schematically shows defects attached in the circumferential direction of the surface. The size of the defect is usually 0.1 mm or more and a few mm, and the depth thereof is a few μm. Among these defects, the one that causes unevenness on the surface cannot sufficiently fix the toner image, resulting in image defects such as white spots on the copy.
In addition, coating unevenness affects the durability of the surface layer. Therefore, the surface inspection of all the cylindrical bodies such as heat rolls is performed.

Surface defects such as "stains" and "unevenness" appear as subtle changes in color tone, and defects such as "scratches" (mechanical scratches) appear as thin lines on the surface of the heat roll. It can be detected. As a surface inspection method, a visual inspection has been conventionally performed by an inspector (see, for example, Japanese Utility Model Laid-Open No. 63-54166). However, the visual inspection has problems such as variation in inspection quality, increase in inspection man-hours, increase in inspection space, deterioration of work environment due to visual fatigue, difficulty in securing workers, and increase in training time for workers. As the automation of the visual inspection work, the following has been proposed as an application of the one for the photosensitive drum.

FIG. 6 is an explanatory view of a first example of the conventional automatic inspection device for the surface of the photosensitive drum, in which the spot light of the laser 113 is passed through the deflector 114 and the surface of the photosensitive drum 111 which is the object to be inspected. The line is scanned above, and the light collected by the defects on the inspection surface is collected by the condenser 112, guided by the optical fiber bundle 115, received by the light receiver 116 composed of a photomultiplier tube, and the predetermined threshold value is set by the calculation means 117. The calculation is performed, and the calculation result is displayed on the display means 118 (Japanese Patent Laid-Open No. 6-68242).
0-86405). However, in this conventional example, there is a problem that interference fringes are generated in the photosensitive layer and the inspection accuracy is lowered.

FIG. 7 is an explanatory view of a second example of a conventional automatic inspection device for the surface of a cylindrical body, in which the surface of the photosensitive drum 141 is illuminated by an illuminating device 143, and reflected light is imaged at an equal magnification 145.
The defect data obtained by forming an image on the sensor array 146 with the image processing device 147 is processed by the surface means 148.
(Japanese Patent Laid-Open No. 3-54438).

FIG. 8 is an explanatory view of a third example of the conventional automatic inspection device for the surface of a cylindrical body, in which 81a and 81b are halogen light sources, 82a and 82b are optical fiber bundles, and 84.
Is a lens holder, 85 is a cylinder lens forming a reduction optical system, 86 is a cylindrical body, 88 is a slit light device, and 89 is a line sensor. As shown in the figure, the light from the halogen light sources 81a and 81b is transmitted to the optical fiber bundles 82a and 81a.
The slit light passing through 82b and the slit light device 88 is reduced by the cylinder lens 85 and applied to the axial surface of the cylindrical body 86, and the reflected light is received by the line sensor 89 to detect the surface defect.

FIG. 9 is an explanatory view of a fourth example of an automatic inspection device for the surface of a cylindrical body. 191 is a photosensitive drum, 192 is a slit light source consisting of a fluorescent lamp 1921 and a slit 1922, and 193 is a light receiving unit consisting of a line sensor. Reference numeral 194 is a projected light image, 195 is a central portion of the projected light image, 196 is a boundary portion of the projected light image, 197 is an image processing portion, and 198 is a defect determination portion.

As shown in the figure, in this apparatus, a white light source forming a slit light source 192 is used as a light source, and a projected light image 19 on the surface of a photosensitive drum 191 which is an object to be inspected is used.
The central portion 195 and the boundary portion 196 of No. 4 are received by the photodetector 193 composed of a line sensor, and the received light signal is received by the image processing unit 197.
And the defect is judged by the defect judgment unit 198, which has been previously proposed by the present inventors (Japanese Patent Application No. 3-2714787).

FIG. 10 is a schematic view for explaining a schematic structure of a surface defect inspection apparatus for a cylindrical body according to another application of the present applicant, in which 90 is a cylindrical body, 91 is the surface of the cylindrical body, and 92 is Projector, 93 is a projected light image, 94 is a surface outside the projected light image area, 95 is a field of view of a light receiver, 96 is a defect, 97 is a light receiver,
Reference numeral 98 is a reduction optical system, 99 is a three-axis attitude adjustment device, 100 is a defect signal extraction unit, and 101 is a defect determination processing unit.

In the figure, a fluorescent lamp is used as a light source forming the floodlight 92, a slit is provided on the front surface of the fluorescent lamp along the longitudinal direction of the fluorescent lamp, and a surface 91 of the cylindrical body 90 is provided.
On the other hand, the long axis thereof is installed in the direction orthogonal to the axial direction of the cylindrical body 90, and the band-shaped projected light image 93 is formed. The light projector 92 and the light receiver 97 move synchronously along the axial direction (longitudinal direction) of the cylindrical body 90.

When the scanning of the cylindrical body 90 along the axial direction is completed, the cylindrical body is rotated by a certain angle (an angle corresponding to the longitudinal width of the band-shaped projected light image). The entire area of the surface 91 of the cylindrical body 90 is scanned by alternately performing the longitudinal scanning of the cylindrical body and the rotational scanning of the cylindrical body. The longitudinal direction of the line sensor forming the light receiver 97 is aligned with the boundary portion of the strip-shaped projected light image 93, and the reflected light near the boundary line (near the boundary portion) is received through the reduction optical system 98.

The light-receiving visual field 95 of the line sensor is set by the three-axis posture adjusting device 99 so as to coincide with the above-mentioned boundary portion. When the boundary portion of the projected light image 93 is scanned in the vicinity of the dent or bulge defect 96 on the surface, the boundary line portion (edge portion) of the projected light image 96 is disturbed, and scattered light is received by the light receiving field 95. The line sensor photoelectrically converts the reflected light in the vicinity of this boundary portion, supplies the output signal to the defect signal extraction circuit 100 to extract the defect signal, and the defect determination processing unit 101 determines whether the defect is good or not and the defect type determination device determines. Be seen.

[0015]

However, among the prior arts of FIGS. 6 to 8 described above, the one using laser light requires a dark room condition, the size of the apparatus becomes large, and the surface of the heat roll to be inspected. Is a relatively rough surface (low gloss surface), so that the laser spot light is scattered and it is difficult to distinguish the normal surface from the defective portion. Further, since the same-magnification imaging element is used, there is a problem that a sensor array or an imaging element having a width larger than the inspection drum width is required and the apparatus becomes large in size.
In the case of using the halogen slit light of 2a and 92b, there is a problem that subtle color unevenness cannot be detected.

The automatic inspection device described with reference to FIG.
As a result of experiments conducted by the present inventors, foreign matter and dents were detected at the position 195 at which the specular reflection light of the slit light on the roll surface 191 was received.
It has been found that the type of main defects such as color unevenness can be detected by the position 196 where the scratches and diffused light are received. Also,
The irregularities on the surface of the cylindrical body can be detected by the position 196 where the scattered light is received at the boundary portion of the regular reflection light reception, and the axial defect 41 among the line-shaped defects such as “dents” and “scratches”.
(See FIG. 5) can be detected, but with respect to streak-like “dents” and abrasions 42 that are continuous in the circumferential direction, as shown in the schematic diagram shown in FIG. 11, the slit 62 has an axial direction of the cylindrical body 60. That is, by being orthogonal to the direction of the streak defect 41,
Since the slit light 63 is irradiated at a wide angle with respect to the inclination of the surface, there is no shadow portion, and there is a problem in that streaky “dents” and abrasions 42 continuous in the circumferential direction cannot be detected.

On the other hand, the cylindrical body 9 described with reference to FIG.
The slit light is projected from the light source 92 arranged in the direction (circumferential direction) orthogonal to the axial surface 91 of 0, and the bright portion (projection light image 93) and the dark portion (projection light image area) are formed in the axial direction of the cylindrical body. In the method of forming only one set of the outer surface 94) and detecting the reflected light at the boundary portion 95, the dent defect 9 in the circumferential direction of the cylindrical body is detected.
6 is detectable. This detection target is a mirror surface OPC
On the surface of the photoconductor drum having a low gloss which is the object of the present invention, the boundary portion 95 between the bright portion and the dark portion has a wide range, while the bright portion and the dark portion are also clear. Therefore, with this device,
A light projector 92 for projecting slit light in a direction orthogonal to the cylinder axis direction is arranged, and a light receiver 97 for receiving light is also arranged in a direction perpendicular to the cylinder axis direction. The light projector 92 and the light receiver 97 are synchronized with each other. Since the structure is such that the entire surface of the photoconductor drum is scanned by moving the device, the size of the apparatus becomes large and the inspection takes time.

The object of the present invention is to solve the above-mentioned problems of the prior art and to apply a surface layer of fluororesin or fluororubber to the surface of a metal base tube (cylindrical substrate) of aluminum or the like via an adhesive. Later, among the defects that occur on the surface of a heat roller with a smooth curved surface by polishing the surface, or on the surface of a cylindrical body with a low gloss surface such as a pressure roller, especially "dents" that are gentle in the circumferential direction Another object of the present invention is to provide a surface defect inspection method and apparatus capable of detecting a "bulge" defect.

[0019]

In order to achieve the above object, the present invention provides a bright portion 11 on the surface of a cylindrical body 1 having a low gloss surface 2 along an axial direction 15 of the cylindrical body 1. A slit light image 10 having a repeating pattern of dark and dark portions 12 is formed, and a light and dark portion 13 region intermediate between the light portion 11 and the dark portion 12 of the slit light image 10 due to the surface defect 5 existing on the low-gloss surface 2. The method is characterized in that the surface defect is detected based on the change in the reflected light level.

Further, the present invention is an apparatus for inspecting surface defects by irradiating the surface of a cylindrical body 1 having a low gloss surface 2 with light and receiving the reflected light to inspect for surface defects. A slit light source 3 having a light shielding plate 8 for forming a slit light image 10 of a repeating pattern of bright portions 11 and dark portions 12 along the axial direction 15 of the cylindrical body 1 on the transparent surface 2,
The line sensor 6 for scanning the slit light image 10 formed on the low-gloss surface 2 of the cylinder 1 along the direction of the axis 15 of the cylinder 1, and the bright portion 11 and the dark portion 12 of the slit light image 10. Repeat pattern 15 in the axial direction of the cylindrical body 1
And a light shielding plate moving mechanism 9 for moving the slit light image 1 by the surface defect 5 existing on the low gloss surface 2.
It is characterized in that the surface defect 5 is detected along the axial direction 15 of the cylindrical body 1 by the change of the reflected light level of the bright and dark portion 13 between the bright portion 11 and the dark portion 12 of 0.

Further, the present invention is an apparatus for inspecting a surface defect by irradiating the surface of a cylindrical body 1 having a low gloss surface 2 with light, and receiving the reflected light to inspect for surface defects. A slit light source 3 having a light shielding plate 8 for forming a slit light image 10 having a repeating pattern of bright portions 11 and dark portions 12 along the axial direction 15 of the cylindrical body 1 on the transparent surface 2, and the cylindrical body. 1. A line sensor 6 for scanning a slit light image 10 formed on a low-gloss surface 2 of the cylindrical body 1 along an axis 15 direction of the cylindrical body 1, and a cylindrical body rotating mechanism 18 for rotating the cylindrical body 1 around the axis. And the slit light image 10
Existing on the low-gloss surface 2 with a light-shielding plate moving mechanism 9 for moving a repeating pattern of the bright portion 11 and the dark portion 12 along the axial direction 15 of the cylindrical body 1 for each rotation of the cylindrical body 1. The surface defect 5 is detected over the entire surface of the cylindrical body 1 by the change in the reflected light level of the bright and dark part 13 between the bright part 11 and the dark part 12 of the slit light image 10 due to the surface defect 5. Characterize.

The slit light source 3 has a grid-shaped light-shielding plate 8 having an opening 7 in front of a linear light source such as a fluorescent lamp, and has a bright portion 11 and a dark portion in the axial direction 15 of the cylindrical body 1. 12
The slit light 4 having a repeating pattern is formed. The line sensor 6 is a slit light image 1 projected on the cylindrical body 1.
0 is scanned in the axial direction 15, and the light-dark portion 13 in the middle of the light portion 11 and the dark portion 12 is set as the inspection range, and the light-shielding plate 8 is moved in the longitudinal direction 14 of the slit light source 3 every time the roll rotates. The light shielding plate moving mechanism 9 is provided.

[0023]

As shown in FIG. 1, the slit light 4 from the slit light source 3 becomes a lattice-shaped slit light image 10 by the light shielding plate 8, and the bright portion in the direction of the cylinder axis 15 on the surface 2 of the cylinder 1 is shown. Irradiation is performed so that the illuminance distribution is a repeating pattern of 11, the bright and dark portions 13, and the dark portions 12. When the cylindrical body 1 is rotated and surface defects such as gentle dents and abrasions in the circumferential direction reach the bright and dark portions of the slit light, as shown in FIG. Light 4 is surface defect 5
The portion of becomes a shadow or a scattering portion 61. This is detected by the line sensor 6 which scans in the axial direction 15 of the cylindrical body 1 along the center line portion 17 of the slit light image 10.

After the cylindrical body 1 makes one rotation, the slit light moving mechanism 9 moves the slit in the horizontal direction (longitudinal direction 14 of the slit light source 3) to form a slit light image 10 on the non-mirror surface 2 of the cylindrical body 1. The entire surface of the cylindrical body 1 is inspected by moving the bright and dark parts and sequentially repeating this.

[0025]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view for explaining an embodiment of an apparatus configuration for applying a method for inspecting a surface defect of a cylindrical body according to the present invention, in which 1 is a cylindrical body to be inspected and 2 is a low gloss surface of the cylindrical body. 3 is a slit light source, 4 is slit light, 5 is a surface defect, 6 is a line sensor, 7 is an opening of a light shielding plate, 8 is a light shielding plate, 9 is a light shielding plate moving mechanism, 10 is a slit light image, 11 is The bright part of the slit light image, 12 is the same dark part, 1
Reference numeral 3 is a bright / dark portion between the bright portion and the dark portion of the slit light image, 1
4 is the slit light horizontal movement direction, 15 is the cylindrical body axial direction, 1
6 is a light-shielding portion, 17 is a center line portion of slit light, and 18 is a cylindrical body rotating mechanism.

In the figure, the slit light source 3 comprises a line-shaped light source having a lattice-shaped light-shielding plate 8 installed in front thereof, and the light-dark repeating slit light 4 passing through the light-shielding plate 8 is used to inspect the surface of the cylindrical body 1. Slit light image 1 by illuminating (low gloss surface 2)
Form 0. It is preferable to use a white fluorescent lamp as a diffused light source for the slit light source because the diffused surface has a high illuminance and a uniform light amount distribution. According to experiments conducted by the present inventors, the distance from the slit light source 3 to the surface 2 of the cylindrical body 1 is about 100 mm, the circumferential width of the cylindrical body of the slit light source 3 is about 30 mm, and a cylinder having a diameter of 17 mmφ. A slit light image 10 having a width of about 1.5 mm is obtained in the circumferential direction on the body surface.

A lattice-shaped light-shielding plate 8 is installed on the front surface of the slit light source 3 to form a repeating pattern of a dark portion 12, a bright / dark portion 13, a bright portion 11, a bright / dark portion 13, a dark portion 12 ...
The surface 2 of the cylindrical body 1 is a rough surface (low gloss surface) to some extent, the boundary portion between the bright portion 11 and the dark portion 12 is not clear as compared with the OPC photosensitive drum, and the area of the bright and dark portion 13 is wide. According to experiments conducted by the present inventors, the dent defect in the circumferential direction of the cylindrical body becomes a black shadow in the area of the bright and dark portion 13 or becomes visible by being scattered brightly. This is because the irradiation of light on the defective portion in the bright and dark portion 13 is
This is because the irradiation light 4 from the opening 72 (FIG. 12) of the light shielding plate 8 is the irradiation light from an angle from one direction.

Since the bright and dark portions 13 are formed at a plurality of positions by the repeating pattern of the slit light 4, it is possible to scan the line sensor 6 in the axial direction 15 of the cylindrical body 1, which is faster than the method described in FIG. Inspection is possible. The setting of the opening 7 and the light shielding portion 16 of the light shielding plate 8 becomes an important factor in the detection time of the dent in the circumferential direction of the cylindrical body 1. The width and ratio of the opening 7 and the light-shielding portion 16 determine the width of the light-dark portion 13 that enables defect detection. The width of the bright and dark portion 13 determines the number of times the light shielding plate 8 is switched and the time for rotating the cylindrical body 1 to inspect the entire surface.

According to the experiment, the width of the bright and dark portions is the largest, and it is possible to detect the indentation in the circumferential direction with high sensitivity. The width of the opening 16 is 10 mm and the width of the light shielding portion is 30 mm.
For example, a depression having a width of 0.4 mm, a circumferential length of 2 mm, and a depth of several μm was detected in the circumferential direction. A dark portion 12 formed on the surface 2 of the cylindrical body 1,
The ratio of the widths of the light-dark portion 13, the light portion 11, the light-dark portion 13, ... Is 1: 1: 1: 1, and the line sensor 6 uses the light-dark portion 13 as a detection area at the first rotation of the roll and the surface of the cylindrical body 1. The entire circumference is inspected, and then the position of the light shielding plate 8 is moved by the light shielding plate driving mechanism 9 to perform the second rotation of the roll, and the entire circumference inspection of the surface 2 of the entire cylindrical body 1 is completed.

2A and 2B are operation explanatory views in one embodiment of the apparatus configuration to which the method for inspecting a surface defect of a cylindrical body according to the present invention is applied. FIG. 2A is a slit for the first rotation, and FIG. The position of the light image 10 is shown, and 11a, 11b, 12a,
Reference numerals 12b, 13a, and 13b denote the light portion, the dark portion, and the light / dark portion of the first and second rotations of the cylindrical body 1, respectively. In the figure, the light-shielding plate 8 is moved after the first scanning by the drum rotation, so that the light-dark portion 1 on the roll surface of the first rotation is changed.
It is a principal part schematic diagram of FIG. 1 which shows that the distribution of 3a is moving to the bright / dark part 13b of the 2nd rotation.

The opening portion 7 and the light shielding portion 16 of the light shielding plate 8 described above.
With respect to the width of, the light shielding plate 8 may be moved in parallel in the slit light horizontal movement direction by a distance of ¼ of the distance between the openings 7. FIG. 3 is an explanatory diagram of the inspection signal output from the line sensor, where the horizontal axis represents the sensor pixel position of the line sensor,
The vertical axis represents the sensor signal level, 31 is the inspection output from the line sensor, 32 is the high level region, 33 is the low level region, and 34a and 34b are the signal distribution regions.

In the figure, the inspection area is a light and dark portion 13a,
Since it is 13b, the sensor signal 31 of the line sensor 6 (FIG. 1) has the bright portion 11 in the high level region 3 as shown in the figure.
2. While the dark part 12 is in the low level area 33,
The bright and dark portion 13 has a one-sided uneven signal distribution region 34a,
34b. For this, the sensor signal distribution region 3
The defect signal 35 is extracted by setting the threshold value 36 in the positive direction and the threshold value 37 in the negative direction according to 4a and 34b.

In the first rotation of the cylindrical body 1 shown in (a), the sensor signal distribution area 34a of the bright and dark portion 13 is used as an inspection area,
In the second rotation of the cylindrical body 1 shown in (b), the entire surface inspection is achieved by using the signal distribution region 34b as the inspection region in accordance with the bright and dark portion 13b which is moved in parallel by the movement of the light shielding plate 8. The height of the threshold values 36 and 37 with respect to the sensor signal 31 may be experimentally determined by measuring the surface defect of the limit sample.

FIG. 4 is a schematic diagram for explaining an application example of an apparatus configuration for applying the method for inspecting a surface defect of a cylindrical body according to the present invention. 4'is a slit, 5'is a surface defect, 8'is a light-shielding plate, Reference numeral 10 'denotes a slit light image, the same reference numerals as those in FIG. 1 correspond to the same portions, and shows a method for detecting defects other than the defects in the circumferential direction of the cylindrical body described in the above-mentioned embodiment. That is, the surface defect 5 ′ existing in the axial direction of the low-gloss surface of the cylindrical body 1 to be surface-inspected is replaced with the shading plate 8 in FIG. 1, and the shading plate 8 having a uniform slit 4 ′ in the axial direction. 'Is provided and a slit light image 10' parallel to the axial direction of the cylindrical body 1 is provided on the surface 2
The line sensor 6 detects the level change of the reflected light.

In the above embodiment, the light shielding plate 8 having the opening 7 is mechanically moved as the slit light source, but the invention is not limited to this, and for example, a liquid crystal shutter array is provided on the entire surface of the slit light source. The opening portion and the light shielding portion may be formed by providing an electric light shielding means such as. As a result, an arbitrary light-shielding pattern can be formed, it is possible to cope with the change of the parameters of the opening and the light-shielding portion depending on the type of defect, and to significantly reduce the time for switching the light-shielding position during inspection.

Further, in the above description, the heat roll constituting a copying machine or a printer is described as an object to be inspected for detecting a surface defect, but the present invention is not limited to this, and the heat roll is paired with a fixing device as a fixing device. It is also effective for detecting a dent defect in the circumferential direction of pressure rolls, contact charging rolls used, and other rolls manufactured by applying a resin or rubber material to the surface of a pipe-shaped substrate or a shaft-shaped substrate.

[0037]

As described above, according to the present invention,
By projecting slit light having alternating bright and dark parts in the axial direction of a cylinder with a low gloss surface, a bright and dark part in which the direction of light emitted from the axial direction is limited to one direction can be made, In the light and dark part, the circumferential dent defect on the surface of the cylinder becomes a shadow part or a brightly scattered part, and the defect can be detected by detecting this scattered light.

Since the bright and dark portions can be formed at a plurality of positions on the axial surface of the cylindrical body by the slit light image of the repeating pattern of the bright and dark portions, the entire surface of the cylindrical body can be inspected at high speed with the scanning direction of the line sensor as the axial direction. It becomes possible. The present invention is a surface defect capable of detecting a particularly gentle "dent" or "bulge" defect in the circumferential direction only by attaching a light shielding plate to a conventional slit light source device that projects slit light in the axial direction of a cylindrical body. It is possible to provide an inspection method and an apparatus therefor, and it is easy to configure it as an automated device.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of an apparatus configuration to which a method for inspecting a surface defect of a cylindrical body according to the present invention is applied.

FIG. 2 is an operation explanatory diagram in one embodiment of an apparatus configuration to which the method for inspecting a surface defect of a cylindrical body according to the present invention is applied.

FIG. 3 is an explanatory diagram of an inspection signal output from a line sensor.

FIG. 4 is a schematic diagram for explaining an application example of an apparatus configuration to which the cylindrical body surface defect inspection method according to the present invention is applied.

FIG. 5 is an explanatory diagram of surface defects of a cylindrical body having a low gloss surface such as a heat roll.

FIG. 6 is an explanatory diagram of a first example of a conventional automatic inspection device for the surface of a photosensitive drum.

FIG. 7 is an explanatory diagram of a second example of a conventional automatic inspection device for the surface of a cylindrical body.

FIG. 8 is an explanatory diagram of a third example of a conventional automatic inspection device for the surface of a cylindrical body.

FIG. 9 is an explanatory diagram of a fourth example of the automatic inspection device for the surface of the cylindrical body.

FIG. 10 is a schematic diagram illustrating a schematic configuration of a surface defect inspection device for a cylindrical body according to another application of the applicant.

FIG. 11 is an explanatory diagram of a problem in detecting defects such as streak-shaped “dents” and abrasions that are continuous in the circumferential direction.

FIG. 12 is an explanatory diagram of a shadow or a scattering portion generated when a surface defect such as a gentle dent in the circumferential direction or a scratch is located at the bright and dark portion of the slit light.

[Explanation of symbols]

1 ...- Cylinder body to be inspected, 2 ... Low-gloss surface of the cylinder body, 3 ...- Slit light source, 4 ...
・ Slit light, 5 ・ ・ ・ Surface defects, 6 ・ ・ ・ ・ Line sensor, 7 ・ ・ ・ ・ Aperture of light shield plate, 8 ・ ・ ・ ・ Light shield plate, 9 ・ ・ ・ ・ Light shield plate moving mechanism, 10・ ・ ・ ・ Slit light image, 11 ・ ・ ・ ・ Bright part of slit light image, 12 ・ ・ ・ ・
Same dark part, 13 ... Bright and dark part between the bright part and dark part of the slit light image, 14 ...
15 ... Cylindrical body axial direction, 16 ... Light-shielding portion, 17
・ ・ ・ Center line part of slit light, ・ ・ ・ 18 Cylindrical body rotation mechanism.

Claims (3)

[Claims] 1. A slit light image having a repeating pattern of bright portions and dark portions is formed on the surface of a cylindrical body having a low gloss surface along the axial direction of the cylindrical body, and is present on the low gloss surface. A method for inspecting a surface defect of a cylindrical body, wherein the surface defect is detected by a change in a reflected light level in a bright and dark part region located between a bright part and a dark part of the slit light image due to the surface defect. 2. A surface defect inspection apparatus for a cylindrical body, which irradiates the surface of a cylindrical body having a low gloss surface with light and receives the reflected light to inspect for surface defects. A slit light source having a light shielding plate that forms a slit light image of a repeating pattern of bright portions and dark portions along the axial direction of the cylinder with respect to the surface, and a slit formed on the low-gloss surface of the cylinder. A line sensor that scans an optical image along the axial direction of the cylindrical body; and a light shielding plate moving mechanism that moves a repeating pattern of bright and dark portions of the slit optical image in the axial direction of the cylindrical body, It is configured to detect the surface defect along the axial direction of the cylindrical body by a change in the reflected light level of the bright and dark portion in the middle of the bright portion and the dark portion of the slit light image due to the surface defect existing on the glossy surface. Characteristic cylinder Surface defect inspection apparatus. 3. A cylindrical surface defect inspection apparatus for irradiating the surface of a cylindrical body having a low gloss surface with light, and receiving the reflected light to inspect for surface defects. A slit light source having a light shielding plate that forms a slit light image of a repeating pattern of bright portions and dark portions along the axial direction of the cylinder with respect to the surface, and a slit formed on the low-gloss surface of the cylinder. A line sensor that scans an optical image along the axial direction of the cylindrical body, a cylindrical body rotating mechanism that rotates the cylindrical body around its axis, and a repeating pattern of bright and dark portions of the slit optical image that is the cylindrical body. And a light-shielding plate moving mechanism that moves along the axial direction of the cylindrical body for each rotation of the slit light image of the slit light image due to a surface defect existing on the low-gloss surface. For changes in reflected light level Ri surface defect inspection device of the cylinder, characterized in that over the entire surface of the cylindrical body and configured to detect the surface defects.