Inspection device for cylinder and inspection method for cylinder

Abstract

Provided are an inspection device for a cylinder and an inspection method for a cylinder, wherein even in an ordinary environment such as a non-clean room, it is possible to reduce the total amount detected by an inspection to prevent over-detection, while also accurately detecting foreign matter and defects on an outer peripheral surface of a cylinder before platemaking and / or after platemaking, said cylinder being used in gravure printing.　This inspection device for a cylinder includes: a support mechanism that rotatably supports the cylinder; a pressing wiping cloth part that is provided with a wiping cloth on a surface thereof, and presses the wiping cloth on an outer peripheral surface of the cylinder, toward the center of rotation of the cylinder and along a prescribed width, to wipe and clean the outer peripheral surface of the cylinder; and a sensor part that, along the prescribed width, images the outer peripheral surface of the cylinder located further downstream than the pressing location of the pressing wiping cloth part, to detect defects or foreign matter on the cylinder.

Description

Cylinder inspection device and cylinder inspection method

[0001] The present invention relates to a cylinder inspection device and a cylinder inspection method for inspecting the outer peripheral surface of a cylinder used in gravure printing before and / or after platemaking, and in particular to a cylinder inspection device and a cylinder inspection method that prevent overdetection.

[0002] In gravure printing, a gravure cylinder is manufactured by forming minute recesses (cells) corresponding to the image on the cylinder to create a printing plate, and the cells are filled with ink to transfer the ink to the printing substrate. A typical gravure cylinder uses a cylindrical iron or aluminum core as its base material, and multiple layers such as a primer layer and a release layer are formed on the outer surface of the base material, followed by a copper plating layer (plate material) for forming the image. Cells corresponding to the platemaking information (original image) are then formed in the copper plating layer using a laser exposure device, and a surface-hardening coating layer such as chrome plating is then formed to increase the printing durability of the gravure cylinder, completing the platemaking (production of the printing plate surface).

[0003] The present applicant has proposed a fully automatic gravure plate making processing system, such as that shown in Patent Document 1, which performs the above gravure plate making process fully automatically, and has received positive feedback.

[0004] In the above-mentioned plate-making process, a defect inspection is carried out before the plate-making (before the formation of cells) to check whether or not there are any initial defects such as scratches or dents on the smooth outer peripheral surface (copper plating layer) of the gravure cylinder, and there are also known devices for automatically carrying out this inspection (see, for example, Patent Documents 2 and 3).

[0005] The applicant has also proposed a gravure cylinder inspection device and method capable of inspecting the outer peripheral surface (plate surface) of a gravure cylinder after plate making, as shown in Patent Document 4, and this has been well received.

[0006] However, in a conventional gravure cylinder inspection device such as that shown in Patent Document 4, although it can detect adhesion of foreign matter or defects on the plate surface by capturing an image using an image sensor unit, it has the problem of not being able to determine whether the foreign matter is a foreign matter or a defect. Foreign matter is often mistaken for a defect, so when the sensor unit detects something, a human being must observe the plate surface using a microscope or the like to make a final confirmation and judgment.

[0007] Although detection by imaging using an image sensor unit can be highly accurate, for example, if 60 foreign objects or defects are detected in a single inspection, it would take a significant amount of time for a person to manually observe and confirm each one of them using a microscope or the like. Even if foreign objects are found and the plate surface is cleaned and inspected again, there is a risk that floating foreign objects will re-adhere. On the other hand, if detection accuracy is reduced to prevent overdetection, foreign objects or defects may be overlooked. In particular, gravure plates have become increasingly high-resolution in recent years, and more accurate inspection is required to detect even the smallest defects and foreign objects.

[0008] To reduce the total amount detected by inspection and prevent overdetection, it is possible to conduct inspections in a clean room where there is no risk of foreign matter adhering. However, installing a cylinder inspection device in a clean room poses problems such as layout restrictions when incorporating the cylinder inspection device into a fully automatic platemaking system and high costs.

[0009] WO2011 / 125926 JP 05-93694 A JP 2002-254590 A JP 2006-194702

[0010] The present invention has been made in consideration of the above-mentioned problems of the conventional technology, and has as its object to provide a cylinder inspection device and a cylinder inspection method that can reduce the total amount detected by inspection to prevent overdetection, even in a general environment such as a non-clean room, and that can accurately detect foreign matter and defects on the outer peripheral surface of a cylinder used in gravure printing before and / or after platemaking.

[0011] In order to solve the above problems, the cylinder inspection device of the present invention is a cylinder inspection device that inspects the outer peripheral surface of a cylinder used in gravure printing before and / or after platemaking, and includes a support mechanism that rotatably supports the cylinder, a pressing wiping cloth section that is provided on its surface and presses the wiping cloth against the outer peripheral surface of the cylinder toward the center of rotation of the cylinder over a predetermined width to wipe the outer peripheral surface of the cylinder, and a sensor section that images the outer peripheral surface of the cylinder located downstream of the pressing point of the pressing wiping cloth section over a predetermined width to detect defects or foreign matter in the cylinder, and when the cylinder is rotated in a predetermined direction, the pressing point revolves around the outer peripheral surface of the cylinder over the predetermined width, and the imaging point by the sensor section also revolves around the outer peripheral surface of the cylinder over the predetermined width.

[0012] It is preferable that the area from the pressed point to the imaging point on the outer peripheral surface of the cylinder be a clean surface zone.

[0013] It is preferable that the pressing wiping cross section is a linear pressing wiping cross section that has a wiping cloth on its surface and wipes the outer peripheral surface of the cylinder by pressing the wiping cloth toward the center of rotation of the cylinder so as to form at least one line of linear pressing points extending longitudinally over a predetermined width on the outer peripheral surface of the cylinder, and that the sensor section is a line sensor section that images the outer peripheral surface of the cylinder located downstream of the linear pressing points of the linear pressing wiping cross section so as to form at least one line of linear imaging points extending longitudinally over a predetermined width, and detects defects or foreign matter on the cylinder.

[0014] It is preferable that the linear pressing area and the linear imaging area are parallel to each other.

[0015] It is preferable that the sensor portion and the pressing wiping cloth portion are movable in the longitudinal direction of the cylinder 12 by the same moving mechanism.

[0016] It is preferable that the wiping cloth is in the form of a web, and that the pressing wiping cloth section is provided with a wiping cloth unwinding section around which the wiping cloth before use is wound, and a wiping cloth winding section around which the wiping cloth after use is wound.

[0017] It is preferable that the wiping cloth unwinding section is provided with a sensor for detecting the remaining amount of wiping cloth before use.

[0018] It is preferable that the imaging device further includes an illumination unit having a light for illuminating the outer peripheral surface of the cylinder and adjusting the illuminance of the image captured by the sensor unit.

[0019] It is preferable that the cleaning device further includes a cleaning liquid dripping section for dripping cleaning liquid onto the wiping cloth before the wiping cloth is pressed against the outer peripheral surface of the cylinder.

[0020] It is preferable that the printing apparatus further comprises a marking means for making a predetermined mark on the outer peripheral surface of the cylinder corresponding to a defective portion in the plate surface image detected by the sensor section.

[0021] The coefficient of dynamic friction between the wiping cloth and the outer peripheral surface of the cylinder is preferably 0.1 to 1.0.

[0022] It is preferable that the pressing force for pressing the wiping cloth toward the center of rotation of the cylinder over a width of 160 mm is 5N to 100N.

[0023] The cylinder inspection method of the present invention is a cylinder inspection method that uses the cylinder inspection device to inspect the outer peripheral surface of a cylinder used in gravure printing before and / or after platemaking, and is a cylinder inspection method that detects defects or foreign matter on the outer peripheral surface of the cylinder before and / or after platemaking.

[0024] The present invention has the significant effect of providing a cylinder inspection device and a cylinder inspection method that can reduce the total amount detected by inspection to prevent overdetection, even in a general environment such as a non-clean room, and that can accurately detect foreign matter and defects on the outer peripheral surface of a cylinder used in gravure printing before and / or after platemaking.

[0025] The present invention relates to a cylinder inspection device and a method for inspecting a cylinder using the same.

[0026] The following describes embodiments of the present invention, but these embodiments are shown by way of example only, and it goes without saying that various modifications are possible without departing from the technical concept of the present invention. Note that the same members are denoted by the same reference numerals.

[0027] 1 and 2, reference numeral 10 denotes one embodiment of a cylinder inspection device according to the present invention.

[0028] The cylinder inspection device 10 of the present invention is a cylinder inspection device that inspects the outer peripheral surface of a cylinder used in gravure printing before and / or after platemaking, and is configured to include a support mechanism 14 that rotatably supports a cylinder 12, a pressing wiping cloth section 20 that is provided with a wiping cloth 16 on its surface and presses the wiping cloth 16 against the outer peripheral surface 18 of the cylinder 12 toward the center of rotation of the cylinder 12 over a predetermined width D1 to wipe and clean the outer peripheral surface 18 of the cylinder 12, and a sensor section 24 that images the outer peripheral surface 18 of the cylinder 12, which is located downstream of the pressing point 22 of the pressing wiping cloth section 20, over a predetermined width D2, and detects defects or foreign matter in the cylinder.

[0029] The aforementioned "gravure cylinder before plate-making" means a gravure cylinder in which gravure cells have not been formed, and is not particularly limited as long as it is a gravure cylinder before cell formation, and may be at any stage before cell formation, such as a plate base material (aluminum hollow roll), a treated roll on which a plate material such as a copper plating layer has been formed, etc. Furthermore, the aforementioned "gravure cylinder after plate-making" means a gravure cylinder in which gravure cells have been formed, and is not particularly limited as long as it is a gravure cylinder after cell formation, and may be at any stage after cell formation, such as a plate-making roll in which gravure cells have been formed in the plate material, a plate-making roll in which the surface of the cells is covered with a coating layer, etc.

[0030] The sensor unit 24 is preferably a line sensor unit using a line sensor, as will be described later. The above-mentioned meaning of "located downstream" means that the image capturing location 26 by the sensor unit 24 is located downstream of the pressing location 22 of the pressing wiping cloth unit 20 with respect to the rotation of the cylinder, and that the image capturing by the sensor unit 24 is performed after wiping is performed by the pressing wiping cloth unit 20.

[0031] When the cylinder 12 is rotated in a predetermined direction, the pressing point 22 moves around the outer peripheral surface 18 of the cylinder 12 over a predetermined width D1, and the imaging point 26 captured by the sensor unit 24 also moves around the outer peripheral surface 18 of the cylinder 12 over a predetermined width D2. It is preferable that the predetermined widths D1 and D2 are the same width.

[0032] The distance D3 between the image capture point 26 captured by the sensor unit 24 and the pressing point 22 of the wiping cloth unit 20 varies depending on the cylinder diameter, but can be, for example, 0.1 mm to 170 mm, preferably 35 mm to 170 mm, and more preferably 60 mm to 100 mm. The wiping cloth unit 20 creates a clean surface zone 44 from the pressing point on the cylinder's outer surface to the image capture point (see FIG. 3). Because the distance from the pressing point on the cylinder's outer surface to the image capture point is relatively short and the image capture is performed after wiping with a wiping cloth immediately before image capture, the image capture can be performed before dust or other foreign matter has time to adhere (the image capture can be performed in the clean surface zone 44). The wiping cloth unit 20 is movable toward and away from the cylinder 12.

[0033] The support mechanism 14 rotatably supports the cylinder 12, and a rotating shaft 15 inserted into the hollow cylinder portion 13 is rotated by a servo motor or the like. If a rotary encoder is provided to monitor the operating state of the servo motor and the servo motor is connected to a control device, the cylinder 12 can be supported in a rotatable state with precision. For example, the support means described in Patent Document 4 can be used as this support mechanism 14.

[0034] In addition, in the illustrated example, the pressing wiping cloth portion 20 has a wiping cloth 16 on its surface, and is a linear pressing wiping cloth portion that wipes the outer peripheral surface 18 of the cylinder 12 by pressing the wiping cloth 16 toward the center of rotation of the cylinder 12 so as to form at least one row of linear pressing points (pressing points 22 in Figure 3) extending longitudinally over a predetermined width D1 on the outer peripheral surface 18 of the cylinder 12.

[0035] As shown in FIG. 2 , the pressing wiping cloth unit 20 includes an arm 42 that extends and retracts, allowing the pressing wiping cloth unit 20 to move toward and away from the cylinder 12. The extension and retraction of the arm can be controlled, for example, by a combination of a servo motor and a control device. This allows the pressing wiping cloth unit 20 to move the wiping cloth 16 between a wiping position where the wiping cloth 16 is pressed against the outer peripheral surface 18 of the cylinder 12 to wipe the outer peripheral surface 18, and a standby position where the wiping cloth 16 is separated from the outer peripheral surface 18 of the cylinder 12 and does not wipe the outer peripheral surface 18. Because the extension and retraction of the arm allows the pressing wiping cloth unit 20 to move toward and away from the cylinder 12, the cylinder inspection device of the present invention can be applied to various types of cylinders with different diameters.

[0036] The sensor unit 24 is preferably a line sensor. Because the cylinder 12 is cylindrical, an area sensor would distort the captured image, making a line sensor preferable. The sensor unit 24 includes an image sensor unit incorporating an imaging element such as a CCD or CMOS, and captures an image of the outer peripheral surface 18 of the cylinder 12 to obtain plate surface image data. As mentioned above, the image sensor unit is preferably a line sensor (also called a linear sensor). The sensor unit 24 is connected to a computer, which detects defects and foreign matter from the plate surface image data captured from the outer peripheral surface 18 of the cylinder 12. Furthermore, if the cylinder 12 is a cylinder after platemaking, defects and foreign matter can be detected by comparing the plate surface image data captured from the outer peripheral surface 18 of the cylinder 12 with the original image used in platemaking using a computer.

[0037] In the illustrated example, the sensor unit 24 is a line sensor unit that images the outer peripheral surface 18 of the cylinder 12 located downstream of the linear pressing point (pressing point 22 in Figure 3) of the linear pressing wiping cloth portion, which is the wiping cloth 16, so as to form at least one row of linear imaging points (imaging points 26 in Figure 3) extending in the longitudinal direction over a predetermined width, and detects defects or foreign objects in the cylinder 12.

[0038] The sensor unit 24 and the pressing wiping cross unit 20 are movable in the longitudinal direction of the cylinder 12 by the same movement mechanism. The movement mechanism of the sensor unit 24 and the pressing wiping cross unit 20 is intended to allow them to move freely in the longitudinal direction of the cylinder 12 (the direction of the rotation axis; horizontal in the drawing). To allow them to move freely in the longitudinal direction of the cylinder 12, for example, although not shown, a screw shaft, a servo motor that drives the screw shaft, and a linear scale that measures the positions of the sensor unit 24 and the pressing wiping cross unit 20 may be provided, and the servo motor may be controlled by a control device.

[0039] In the example shown in FIG. 3, the linear pressed portion, which is the pressed portion 22, and the linear imaged portion, which is the imaged portion 26, are parallel to each other.

[0040] As shown in Figure 2, the wiping cloth 16 is in the form of a web in the pressing wiping cloth section 20, and the pressing wiping cloth section 20 is provided with a wiping cloth unwinding section 28 around which the wiping cloth 16 before use is wound, and a wiping cloth winding section 30 around which the wiping cloth after use is wound.

[0041] A sensor 32 is also provided to detect the remaining amount of wiping cloth 16 before use in wiping cloth payout section 28. A photoelectric sensor, for example, is suitable as sensor 32. By detecting the remaining amount of wiping cloth 16 before use in wiping cloth payout section 28 with sensor 32, it is possible to replace the wiping cloth 16 with a new web-shaped wiping cloth when the remaining amount becomes low.

[0042] As shown in Figures 1 and 2, the cylinder inspection device 10 is further configured to include an illumination unit 34 equipped with illumination for illuminating the outer peripheral surface 18 of the cylinder 12 and adjusting the illuminance of the image captured by the sensor unit 24.

[0043] Furthermore, the pressing wiping cloth unit 20 is configured to further include a cleaning liquid dripping unit 36 ​​that drips cleaning liquid onto the wiping cloth 16 before the wiping cloth 16 is pressed against the outer peripheral surface 18 of the cylinder 12. Suitable cleaning liquids include, for example, alcohol such as isopropyl alcohol (IPA) and an alcohol-containing mixed solvent obtained by mixing alcohol such as isopropyl alcohol (IPA) with another solvent.

[0044] The pressing wiping cloth section 20 is provided with a rubber roller 38 and a nip roll 40, and the rubber roller 38 presses the wiping cloth 16 toward the center of rotation of the cylinder 12, wiping the outer surface 18 of the cylinder 12 clean.

[0045] It is also preferable to further provide a marking means for making a predetermined mark on the outer peripheral surface 18 of the cylinder 12 corresponding to a defective portion in the plate image detected by the sensor unit 24. A laser pointer, for example, can be used as the marking means.

[0046] The dynamic friction coefficient between the wiping cloth and the outer peripheral surface of the cylinder is preferably 0.1 to 1.0, and more preferably 0.1 to 0.7. When the outer peripheral surface of the cylinder is coated with DLC (diamond-like carbon), the dynamic friction coefficient between the wiping cloth and the outer peripheral surface of the cylinder is preferably 0.15 to 0.20. When the outer peripheral surface of the cylinder is coated with chrome plating, the dynamic friction coefficient between the wiping cloth and the outer peripheral surface of the cylinder is preferably 0.58 to 0.62.

[0047] The pressing force for pressing the wiping cloth 16 toward the center of rotation of the cylinder 12 over a width of 160 mm is preferably 5 to 100 N, and more preferably 30 to 60 N.

[0048] The cylinder inspection method of the present invention is achieved by using the above-described cylinder inspection device 10 to inspect the outer peripheral surface 18 of the cylinder 12 used in gravure printing before and / or after platemaking, and detecting defects or foreign matter on the outer peripheral surface 18 of the cylinder 12 before and / or after platemaking.

[0049] The cylinder inspection device 10 of the present invention can be used as one processing device in a fully automatic gravure plate-making processing system such as that shown in Patent Document 1. That is, by incorporating the cylinder inspection device of the present invention into a fully automatic gravure plate-making processing system such as that shown in Patent Document 1 and arranging it in the handling area of ​​an industrial robot, it is possible to inspect the outer peripheral surface 18 of a cylinder 12 used in gravure printing before and / or after plate-making, and to detect defects or foreign matter on the outer peripheral surface 18 of the cylinder 12 before and / or after plate-making.

[0050] The present invention will be explained in more detail below by way of examples, but it goes without saying that these examples are given for illustrative purposes and should not be construed as limiting.

[0051] Example 1 Preparation of Plate-Making Roll A plate base material (aluminum hollow roll) having a circumference of 600 mm and a face length of 1100 mm was prepared, and the plate-making roll (plate-made gravure cylinder) described below was manufactured using a New FX device (a fully automatic laser gravure plate-making roll manufacturing device manufactured by Think Laboratory Co., Ltd.) Furthermore, a cylinder inspection device having a configuration similar to the cylinder inspection device 10 of the present invention described above was incorporated as one of the processing devices into the fully automatic laser gravure plate-making roll manufacturing device, and the cylinder inspection device was placed in the handling area of ​​an industrial robot.

[0052] First, the plate base material (aluminum hollow roll) was placed in a copper plating tank, and the hollow roll was completely submerged in the plating solution at a current density of 30 A / dm ２ A copper plating layer of 80 μm was formed at a voltage of 6.0 V. The plated surface was free of bumps or pits, resulting in a uniform copper plating layer. The surface of this copper plating layer was polished using a two-head polisher (polished by Think Laboratory Co., Ltd.) to obtain a uniformly polished surface, thereby obtaining a treated roll having a copper plating layer. The outer peripheral surface of the treated roll (gravure cylinder before platemaking) having the copper plating layer obtained above was inspected using the method described below.

[0053] <Cell Formation Step> A photosensitive material (thermal resist: TSER2104E4 (manufactured by Think Laboratory Co., Ltd.)) was applied (using a fountain coater) to the surface of the treated roll having the obtained copper plating layer, and then dried. The film thickness of the obtained photosensitive material was measured with a film thickness meter (F20 manufactured by FILLMETRICS Co., Ltd.) and found to be 4.5 μm. Next, the image was exposed to laser light and developed. The laser exposure was performed using Laser Stream FX under the exposure conditions of 300 mJ / cm. ２ A predetermined pattern of exposure was performed using a TLD developer (developer manufactured by Think Laboratory Co., Ltd.) at a developer dilution ratio of 1 part stock solution to 7 parts water at 24°C for 90 seconds to form a predetermined resist pattern. The copper plating layer was then etched using the formed resist pattern as an etching mask. A cupric chloride solution was used as the etching solution, and the etching was performed by spraying at 35°C for 100 seconds. Next, sodium hydroxide was used at a dilution ratio of 20 g / L at 40°C for 180 seconds to strip the resist pattern. In this manner, numerous square recesses (gravure cells) with a depth of 10 μm and a side length of 100 μm were formed in the solid area. A 3 μm-thick chrome plating layer was formed on the copper plating layer of the plate-making roll on which the gravure cells were formed, and the surface was roll-polished to obtain a plate-making roll (a gravure cylinder on which a plate was made). The outer peripheral surface of the obtained plate-making roll (a gravure cylinder after plate-making) was inspected using the method described below.

[0054] <Inspection of the outer peripheral surface of the gravure cylinder> Using a cylinder inspection device having the structure shown in Figures 1 and 2, the outer peripheral surfaces of the treated roll (gravure cylinder before plate making) having the copper plating layer and the plate making roll (gravure cylinder after plate making) were inspected by the following method. As the wiping cloth for the pressing wiping cloth part, CRN505 (100% polyester, basis weight 211 g / m) manufactured by Miraikosen Co., Ltd. was used. ２A 0.61 mm thick, 160 mm wide, and 330% water retention (after 5 seconds) roll was used. A 20 mm diameter x 160 mm wide urethane rubber roller was used to press the roll with a force of 50 N. The cylinder (the above-mentioned processed roll and plate-making roll) was rotated at a surface speed of 160 to 220 mm / sec. The cylinder's outer surface was then wiped clean with a wiping cloth, and an image of the cylinder's outer surface was captured with a 10 μm resolution optical line camera. The optical line camera was a line sensor. A 10 μm resolution optical line camera can detect defects or foreign matter as small as 20 μm in size. The distance D3 between the image capture point of the sensor line camera and the press point of the press wiping cloth was set between 85 mm and 70 mm. The area from the press point to the image capture point on the cylinder's outer surface was defined as a clean surface zone 44 by the press wiping cloth 20. After capturing images for one rotation of the cylinder, the optical line camera and the pressing wiping cloth were moved longitudinally (toward the axis of rotation; horizontally in the drawing) by 160 mm, the width that the optical line camera can capture in one rotation, and the next 160 mm was captured for one rotation of the cylinder. Depending on the size of the effective printing area to be inspected, capturing images was completed in 2 to 2.5 minutes per cylinder (processed roll and plate-making roll). The imaging time was the same whether the optical line camera was used to capture the outer surface of a copper-plated cylinder (an aluminum hollow roll) or a DLC (diamond-like carbon)-coated cylinder after copper plating, or the base iron surface of an iron hollow roll. When using an optical line camera with a 2.5 μm resolution as the sensor to detect even smaller defects or foreign objects, the cylinder rotation speed had to be slowed to 1 / 4 due to the data transfer rate from the line camera, and the width captured by the camera per rotation of the cylinder was also reduced to 1 / 4. After the image was captured, a computer performed calculations to extract defects, and if a defect was detected, a mark was applied using a marking mechanism mounted next to the camera so that the location of the defect on the cylinder surface could be seen visually.After that, because dirt adheres to the surface of the wiping cloth that has been used once, the wiping cloth is rolled up by about 10 mm each time one plate surface of the cylinder is inspected and moved to an unused surface. The wiping cloth can be left dry, but wetting it with a cleaning liquid such as IPA improves the wiping effect.

[0055] When the outer peripheral surfaces of the treated roll having the copper plating layer (gravure cylinder before plate-making) and the chrome-plated plate-making roll (gravure cylinder after plate-making) were inspected under the conditions described below, the number of defects / foreign matter detected was as follows. Whether or not there was an overdetection (i.e., erroneous detection) was determined by checking the detected locations using a microscope. In the case of the treated roll having the obtained copper plating layer (gravure cylinder before plate-making), pinholes in the copper plating and scratches formed during polishing were detected as defects. 1) Inspection results for the plate-making roll plate-making room (cleanliness: class 10,000 clean room) using a cylinder inspection device without wetting the wiping cloth with IPA; Processed roll: Number of defects / foreign matter detected by the line camera (number of detected by the sensor) was 2, with 2 over-detections, and the number of defects / foreign matter visually detected by the microscope (actual number) was 0. Plate-making roll: Number of defects / foreign matter detected by the sensor was 3, with 1 over-detection, and the actual number was 2. 2) Inspection results for the plate-making roll plate-making room (cleanliness: class 10,000 clean room) using a cylinder inspection device while wetting the wiping cloth with IPA; Processed roll: Number of defects / foreign matter detected by the sensor was 1, with 0 over-detections, and the actual number was 1. Plate-making roll: Number of defects / foreign matter detected by the sensor was 3, with 0 over-detections (no false detections, and defects / foreign matter definitely existed), and the actual number was 3. 3) Results of inspection in a general office environment (non-clean room) using a cylinder inspection device without wetting the wiping cloth with IPA: Processed roll: The sensor detected 3 defects / foreign objects, 2 overdetections, and 1 actual object. Plate-making roll: The sensor detected 3 defects / foreign objects, 1 overdetection, and 2 actual objects. 4) Results of inspection in a general office environment (non-clean room) using a cylinder inspection device while wetting the wiping cloth with IPA: Processed roll: The sensor detected 0 defects / foreign objects, 0 overdetections, and 0 actual objects. Plate-making roll: The sensor detected 3 defects / foreign objects, 0 overdetections, and 3 actual objects.

[0056] (Comparative Example 1) Conventionally, a wiping cloth (e.g., CRN505 manufactured by Miraikosen Co., Ltd.) moistened with IPA or the like was held in hand to wipe the outer peripheral surface of the cylinder, wiping off any foreign matter on the surface, and then an image was taken. Alternatively, an air blower or brush was attached to a position just before the line camera was used to image the outer peripheral surface of the cylinder, and the image was taken while blowing away any foreign matter with the air blower or removing it with the brush. When the outer peripheral surfaces of the above-mentioned copper-plated treated roll (gravure cylinder before platemaking) and chrome-plated platemaking roll (gravure cylinder after platemaking) were inspected using this conventional method under the following conditions, the number of defects / foreign matter detected was as follows. Whether or not there was an overdetection (i.e., erroneous detection) was determined by checking the detected locations using a microscope. 1) In a plate-making roll plate-making room (clean room with cleanliness of class 10,000), a wiping cloth moistened with IPA was held in hand to wipe the outer surface of the cylinder, and then multiple flat-type nozzles such as CKD Corporation's BNE-8P 10F were arranged to blow air onto the outer surface of the cylinder at an air pressure of 0.1 to 0.3 MPa, and then measurements were taken with a line camera immediately after brushing (distance between the line camera and the brush was 80 mm). Processed roll: Number of defects / foreign matter detected by the sensor was 18, with 17 overdetections and 1 actual count. Plate-making roll: Number of defects / foreign matter detected by the sensor was 15, with 12 overdetections and 3 actual count. 2) In a general office environment (non-clean room), a wiping cloth moistened with IPA was held in hand to wipe the outer surface of the cylinder, and then multiple flat-type nozzles such as CKD Corporation's BNE-8P 10F were arranged to blow air onto the outer surface of the cylinder at an air pressure of 0.1 to 0.3 MPa, and then measurements were taken with a line camera immediately after brushing (distance between the line camera and the brush was 80 mm). The results were as follows: Multiple flat-type nozzles such as 10F were arranged to blow air onto the outer surface of the cylinder at an air pressure of 0.1 to 0.3 MPa, and immediately after brushing, measurements were taken with a line camera; Processed roll: The number of defects / foreign matter detected by the sensor was 35, with 35 being overdetected and 0 being the actual number. Plate-making roll: The number of defects / foreign matter detected by the sensor was 43, with 40 being overdetected and 3 being the actual number.

[0057] According to the above results, by using the cylinder inspection device of the present invention and performing the cylinder inspection method of the present invention, it was possible to reduce the total amount detected by inspection and prevent overdetection in both pre- and post-plate-making gravure cylinders. Since overdetection can be prevented even in a general office environment (non-clean room), inspection is possible without installing a cylinder inspection device in a clean room. Furthermore, it was possible to accurately detect foreign matter and defects on the outer peripheral surface of cylinders used in gravure printing before and / or after plate-making.

[0058] 10: Cylinder inspection device, 12: Cylinder, 13: Cylinder hollow portion, 14: Support mechanism, 15: Rotating shaft, 16: Wiping cloth, 18: Outer circumferential surface, 20: Pressing wiping cloth portion, 22: Pressing point, 24: Sensor portion, 26: Imaging point, 28: Wiping cloth unwinding portion, 30: Wiping cloth winding portion, 32: Sensor, 34: Illumination portion, 36: Cleaning liquid dripping portion, 38: Rubber roller, 40: Nip roll, 42: Arm portion, 44: Clean surface zone, D1: Width of pressing point, D2: Width of imaging point, D3: Distance between the imaging point of the sensor portion and the pressing point of the pressing wiping cloth portion.

Claims

1. A cylinder inspection device that inspects the outer peripheral surface of a cylinder used in gravure printing before and / or after plate making, comprising: a support mechanism that rotatably supports the cylinder; a pressing wiping cloth section that has a wiping cloth on its surface and presses the wiping cloth against the outer peripheral surface of the cylinder over a predetermined width toward the center of rotation of the cylinder to wipe and clean the outer peripheral surface of the cylinder; and a sensor section that takes an image of the outer peripheral surface of the cylinder located downstream from the pressing point of the pressing wiping cloth section over the predetermined width and detects defects or foreign matter on the cylinder; and when the cylinder is rotated in a predetermined direction, the pressing point moves around the outer peripheral surface of the cylinder over the predetermined width, and the imaged point by the sensor section also moves around the outer peripheral surface of the cylinder over the predetermined width.

2. A cylinder inspection device according to claim 1, wherein the area from the pressed point to the imaging point on the outer peripheral surface of the cylinder is a clean surface zone.

3. A cylinder inspection device as set forth in claim 1, wherein the pressing wiping cloth section is a linear pressing wiping cloth section that has a wiping cloth on its surface and wipes the outer peripheral surface of the cylinder by pressing the wiping cloth toward the center of the cylinder so as to form at least one line of linear pressing points extending longitudinally over a predetermined width on the outer peripheral surface of the cylinder, and the sensor section is a line sensor section that images the outer peripheral surface of the cylinder located downstream of the linear pressing points of the linear pressing wiping cloth section so as to form at least one line of linear imaging points extending longitudinally over a predetermined width, thereby detecting defects or foreign matter on the cylinder.

4. The cylinder inspection device according to claim 3, wherein the linear pressing portion and the linear imaging portion are parallel to each other.

5. The cylinder inspection device according to claim 1, wherein the sensor section and the pressing wiping cloth section are movable in the longitudinal direction of the cylinder by the same moving mechanism.

6. The cylinder inspection device according to claim 1, wherein the wiping cloth is in the form of a web, and the pressing wiping cloth section is provided with a wiping cloth unwinding section around which the wiping cloth before use is wound, and a wiping cloth winding section around which the wiping cloth after use is wound.

7. The cylinder inspection device according to claim 6, further comprising a sensor for detecting the remaining amount of wiping cloth before use at said wiping cloth unwinding section.

8. The cylinder inspection device according to claim 1, further comprising an illumination unit provided with illumination for illuminating the outer peripheral surface of said cylinder and adjusting the illuminance of the image taken by said sensor unit.

9. The cylinder inspection device according to claim 1, further comprising a cleaning liquid dripping unit for dripping cleaning liquid onto the wiping cloth before the wiping cloth is pressed against the outer peripheral surface of the cylinder.

10. The cylinder inspection device according to claim 1, further comprising marking means for making a predetermined mark on the outer peripheral surface of the cylinder corresponding to a defective portion in the plate surface image detected by said sensor section.

11. The cylinder inspection device according to claim 1, wherein the coefficient of dynamic friction between the wiping cloth and the outer peripheral surface of the cylinder is 0.1 to 1.

0.

12. The cylinder inspection device according to claim 1, wherein the pressing force for pressing the wiping cloth toward the center of the cylinder over a width of 160 mm is 5N to 100N.

13. A cylinder inspection method using the cylinder inspection device of any one of claims 1 to 12 to inspect the outer peripheral surface of a cylinder used in gravure printing before and / or after plate making, which is designed to detect defects or foreign matter on the outer peripheral surface of the cylinder before and / or after plate making.

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