Method and apparatus for manufacturing glass article

Abstract

To detect positional deviation in the width direction of a glass ribbon conveyed in the longitudinal direction.SOLUTION: A method for manufacturing a glass article comprises: the imaging step S31 of imaging the ends GRa and GRb of a glass ribbon GR in the width direction X by imaging devices 16a and 16b while conveying the glass ribbon GR in the longitudinal direction Y; and the detection step S32 of detecting positions of the ends GRa and GRb of the glass ribbon GR on the basis of an image 19 imaged in the imaging step S31.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for manufacturing glass articles, such as glass sheets. [Background technology]

[0002] As is well known, glass sheets are used as components for displays such as liquid crystal displays and organic EL displays, and for mobile terminals such as smartphones. The downdraw method is widely used as a method for manufacturing glass sheets. Known downdraw methods include, for example, the overflow downdraw method and the slot downdraw method.

[0003] The overflow downdraw method involves pouring molten glass into an overflow groove provided at the top of a forming body having a generally wedge-shaped cross section, allowing the molten glass overflowing from the overflow groove to flow down along both sidewalls of the forming body and to fuse and integrate at the lower end of the forming body, thereby continuously forming a single glass ribbon.The slot downdraw method involves forming a slot-shaped opening in the bottom wall of the forming body to which molten glass is supplied, and allowing the molten glass to flow down through this opening to continuously form a single glass ribbon.

[0004] For example, Patent Document 1 discloses a method for manufacturing a glass sheet using an overflow downdraw method. This manufacturing method uses a forming zone in which a glass ribbon is formed from molten glass using a forming body, an annealing zone in which the glass ribbon descending from the forming zone is guided downward and gradually cooled, and a cooling zone in which the glass ribbon that has passed through the annealing zone is pulled downward by support rollers and cooled, and the glass ribbon that has passed through the cooling zone is obtained as a strip-shaped glass sheet (glass film) (see claim 1 of the same document).

[0005] In this manufacturing method, the glass ribbon is conveyed in the longitudinal direction by edge rollers provided in the forming zone, annealing rollers provided in the annealing zone, and support rollers provided in the cooling zone (see paragraphs 0032 to 0038 of the same document). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2022-91351 Summary of the Invention [Problem to be solved by the invention]

[0007] In a conventional method for manufacturing a glass article, the glass ribbon may meander due to movement in its width direction during conveyance, resulting in misalignment of the glass ribbon. When misalignment occurs in the glass ribbon during conveyance, the warp or distortion of the glass ribbon may change, causing an abnormality in the quality of the glass ribbon.

[0008] The present invention has been made in view of the above circumstances, and has as its technical object to detect a positional deviation in the width direction of a glass ribbon that is transported in the vertical direction. [Means for solving the problem]

[0009] (1) The present invention is intended to solve the above-mentioned problems, and is a method for manufacturing a glass article, comprising a forming step of forming a glass ribbon from molten glass, and an annealing step of annealing the formed glass ribbon in an annealing furnace while transporting the glass ribbon in a vertical direction, and is characterized by comprising an imaging step of imaging an end portion in the width direction of the glass ribbon while transporting the glass ribbon in the vertical direction, and a detection step of detecting the position of the end portion of the glass ribbon based on the image captured in the imaging step.

[0010] According to this configuration, by detecting the position of the end of the glass ribbon in the detection step based on the image of the end of the glass ribbon acquired in the imaging step, if a positional deviation occurs in the glass ribbon during transport, the positional deviation can be detected from a change in the position of the end of the glass ribbon. By detecting an abnormality in the transport of the glass ribbon in this manner, it is possible to detect quality abnormalities due to changes in warp or distortion of the glass ribbon at an early stage, and to take appropriate measures to resolve the abnormality.

[0011] (2) In the method for manufacturing a glass article described in (1) above, in the imaging step, light may be irradiated onto the end portion of the glass ribbon by an illumination device.

[0012] According to this configuration, when the lighting device irradiates the end of the glass ribbon with light, the end of the glass ribbon becomes dark or black. In the image captured by the imaging device, the position of the end of the glass ribbon can be easily detected based on the darkened or blackened portion.

[0013] (3) In the method for manufacturing a glass article described in (1) or (2) above, the detection step may use an image processing device to detect the position of the end based on one or more of the hue, saturation, and brightness of the end of the glass ribbon contained in the image.

[0014] According to this configuration, it becomes easier to identify the position of the end of the glass ribbon in an image including the end of the glass ribbon.

[0015] (4) In the method for manufacturing a glass article described in any one of (1) to (3) above, the detection step may detect the width of the ear portion included in the end of the glass ribbon based on the image captured in the imaging step.

[0016] The ears formed at the ends of the glass ribbon have a thickness greater than that of the product portion (useful portion) in the center of the glass ribbon. If the width of these ears decreases, the strength of the ends of the glass ribbon may decrease, which may lead to breakage of the glass ribbon. Furthermore, if the width of the ears increases, this may cause poor cutting when the glass ribbon is cut in a later process. According to the present invention, by detecting the width of the ears at the ends of the glass ribbon in the detection process, it is possible to detect abnormalities in the ears early and take appropriate action.

[0017] (5) In the method for manufacturing a glass article described in (4) above, the detection step may use an image processing device to detect the width of the ear portion based on one or more of the hue, saturation, and brightness of the end portion of the glass ribbon contained in the image.

[0018] According to this configuration, it becomes easier to identify the width of the ear portion at the end of the glass ribbon in an image including the end of the glass ribbon.

[0019] (6) In the method for producing a glass article according to any one of (1) to (5) above, the imaging step may be carried out below the annealing furnace.

[0020] According to this configuration, the imaging step is performed at a position below and away from the annealing furnace, thereby preventing the imaging device used in the imaging step from being damaged by the heat of the annealing furnace.

[0021] (7) In the method for manufacturing a glass article according to any one of (1) to (6) above, the method may further include a cooling step of cooling the glass ribbon that has undergone the annealing step while transporting it in a vertical direction, and a cutting step of cutting a glass plate out of the glass ribbon after the cooling step, and the imaging step may be performed during the cooling step.

[0022] According to this configuration, the temperature of the glass ribbon is lower in the cooling process than in the annealing furnace, so that the imaging device used in the imaging process is prevented from being exposed to high temperatures, and therefore, failure of the imaging device can be prevented. Also, compared to when the imaging process is performed between the cooling process and the cutting process, the glass ribbon vibrates less, so that misalignment of the glass ribbon can be easily detected. From this perspective, it is more preferable to perform the imaging process upstream of the cooling process (upstream of the cooling zone described below).

[0023] (8) The method for manufacturing a glass article according to any one of (1) to (7) above may further include a determination step for determining whether the position of the end of the glass ribbon is good or bad, and in the determination step, when the position of the end of the glass ribbon exceeds a reference value, it may be determined that excessive misalignment has occurred in the glass ribbon, and a countermeasure step for changing conditions for the forming step and / or the annealing step when excessive misalignment of the glass ribbon is determined.

[0024] According to this configuration, when excessive misalignment of the glass ribbon is detected in the determination process, the excessive misalignment can be eliminated by changing the conditions of the forming process and / or the annealing process.

[0025] (9) The present invention is intended to solve the above-mentioned problems, and is a glass article manufacturing apparatus comprising: a forming device that forms a glass ribbon from molten glass; a conveying device that conveys the glass ribbon vertically; and an annealing furnace that anneals the glass ribbon conveyed by the conveying device, characterized in that it also comprises an imaging device that images the widthwise end of the glass ribbon conveyed by the conveying device; and an image processing device that detects the position of the end of the glass ribbon based on the image captured by the imaging device.

[0026] According to this configuration, by using the image processing device to detect the position of the end of the glass ribbon based on the image of the end of the glass ribbon acquired by the imaging device, if a positional deviation occurs in the glass ribbon during transport, this positional deviation can be detected from a change in the position of the end of the glass ribbon. By detecting an abnormality in the transport of the glass ribbon in this manner, it is possible to detect quality abnormalities due to changes in warp or distortion of the glass ribbon at an early stage and to take appropriate measures to resolve this abnormality. [Effects of the Invention]

[0027] According to the present invention, it is possible to detect positional deviation in the width direction of a glass ribbon that is transported in the vertical direction. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 2 is a cross-sectional view showing a glass sheet manufacturing apparatus. [Figure 2] FIG. 2 is a front view showing the glass sheet manufacturing apparatus. [Figure 3] FIG. 3 is a cross-sectional view taken along the line of the arrows III-III in FIG. 2. [Figure 4] FIG. 2 is a plan view showing an imaging device and an illumination device. [Figure 5] FIG. 2 is a diagram illustrating an example of an image captured by an imaging device. [Figure 6] FIG. 2 is a diagram illustrating an example of an image captured by an imaging device. [Figure 7] 1 is a flowchart showing a method for manufacturing a glass article. [Figure 8] 1 is a flowchart showing an inspection process in a glass article manufacturing method. DETAILED DESCRIPTION OF THE INVENTION

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Figures 1 to 8 show an embodiment of a glass article manufacturing apparatus and manufacturing method according to the present invention.

[0030] As shown in Figures 1 and 2, the glass article manufacturing apparatus 1 includes a forming furnace 2 that forms a glass ribbon GR from molten glass GM, an annealing furnace 3 that slowly cools (anneals) the glass ribbon GR, a cooling zone 4 that cools the glass ribbon GR to near room temperature, and a cutting device 5 that is arranged below the cooling zone 4.

[0031] The glass ribbon GR is a long, transparent glass sheet having a predetermined width. Hereinafter, one end of the glass ribbon GR in the width direction X is referred to as a first end GRa, and the other end of the glass ribbon GR in the width direction X is referred to as a second end GRb. In the following description, one main surface of the glass ribbon GR is referred to as a first main surface GR1, and the other main surface is referred to as a second main surface GR2.

[0032] As shown in Fig. 3 , the first end GRa and the second end GRb of the glass ribbon GR include edge portions TP that are thicker than effective portions located at the center of the glass ribbon GR in the width direction X, and non-effective portions that are formed between the effective portions and the edge portions TP. The effective portions are portions that correspond to glass sheets as glass articles cut out from the glass ribbon GR, and the non-effective portions are portions that are thinner than the edge portions TP and are non-product portions that are cut out together with the edge portions TP.

[0033] A forming device 6 that forms a glass ribbon GR from the molten glass GM by the overflow downdraw method is disposed in the internal space of the forming furnace 2. The forming device 6 includes a forming body 7 and edge rollers 8a and 8b.

[0034] The molded body 7 is made of, for example, an alumina-based or zirconia-based refractory brick, but the material of the molded body 7 is not limited to that in this embodiment.

[0035] 1 and 2, the forming body 7 has an overflow groove 9 at its upper part for overflowing the molten glass GM. In addition, the forming body 7 has a pair of side wall surfaces 10, 11 through which the molten glass GM flows down, and a lower end portion 12 that fuses the molten glass GM flowing down the pair of side wall surfaces 10, 11.

[0036] The edge rollers 8a, 8b include a first edge roller 8a that clamps a first end GRa of the glass ribbon GR, and a second edge roller 8b that clamps a second end GRb of the glass ribbon GR. The edge rollers 8a, 8b are provided below the forming body 7 and are configured as a roller pair that clamps each end GRa, GRb of the glass ribbon GR formed by the forming body 7. The roller pair includes a roller arranged on the first main surface GR1 side of the glass ribbon GR, and a roller arranged on the second main surface GR2 side of the glass ribbon GR.

[0037] The pair of rollers constituting the edge rollers 8a, 8b are configured to be able to move individually along the thickness direction T of the glass ribbon GR. This allows the edge rollers 8a, 8b to adjust the clamping pressure on the glass ribbon GR.

[0038] The annealing furnace 3 is provided below the forming furnace 2. The annealing furnace 3 anneals the glass ribbon GR sent downward from the forming furnace 2 while transporting it in the vertical direction Y. As shown in FIGS. 1 and 2 , multiple stages of upper and lower transport rollers 13a, 13b for transporting the glass ribbon GR are arranged inside the annealing furnace 3. The transport rollers 13a, 13b include a first transport roller 13a arranged on the side of a first end GRa of the glass ribbon GR and a second transport roller 13b arranged on the side of a second end GRb of the glass ribbon GR. Each transport roller 13a, 13b clamps an ineffective portion of the glass ribbon GR that is located inside the edge portion TP of the glass ribbon GR so as not to come into contact with the edge portion TP of the glass ribbon GR.

[0039] The conveying rollers 13a, 13b are configured as a roller pair that sandwiches each end GRa, GRb of the glass ribbon GR. The roller pair includes a roller arranged on the first main surface GR1 side of the glass ribbon GR and a roller arranged on the second main surface GR2 side of the glass ribbon GR. Each roller is configured to be independently movable along the thickness direction T of the glass ribbon GR. This allows the conveying rollers 13a, 13b to adjust the sandwiching pressure on the glass ribbon GR.

[0040] The cooling zone 4 is provided below the annealing furnace 3. In the cooling zone 4, multiple stages of support rollers 14a, 14b are arranged in upper and lower rows to transport the glass ribbon GR. The support rollers 14a, 14b include a first support roller 14a arranged on the side of a first end GRa of the glass ribbon GR and a second support roller 14b arranged on the side of a second end GRb of the glass ribbon GR. Each support roller 14a, 14b clamps an ineffective portion of the glass ribbon GR that is located inside the edge portion TP of the glass ribbon GR so as not to come into contact with the edge portion TP of the glass ribbon GR.

[0041] The support rollers 14a, 14b are configured as a pair of rollers that sandwich each end GRa, GRb of the glass ribbon GR. The pair of rollers includes a roller arranged on the first main surface GR1 side of the glass ribbon GR and a roller arranged on the second main surface GR2 side of the glass ribbon GR. Each roller is configured to be independently movable along the thickness direction T of the glass ribbon GR. This allows the support rollers 14a, 14b to adjust the sandwiching pressure on the glass ribbon GR.

[0042] 1, an inspection device 15 that inspects the position of the glass ribbon GR is disposed in the cooling zone 4, more specifically, on the upstream side of the cooling zone 4. The inspection device 15 includes imaging devices 16a and 16b that capture images of the ends GRa and GRb of the glass ribbon GR, lighting devices 17a and 17b that irradiate the glass ribbon GR with light L, and an image processing device 18.

[0043] 1 and 2, the imaging devices 16a and 16b are disposed below the annealing furnace 3. The imaging devices 16a and 16b are disposed above the detection position DP of the glass ribbon GR. Therefore, the imaging devices 16a and 16b are in an inclined position facing diagonally downward as shown in Fig. 1. However, the imaging devices 16a and 16b may be disposed in a horizontal position.

[0044] The imaging devices 16a, 16b image each end GRa, GRb at a detection position DP set in the middle of the glass ribbon GR transported in the longitudinal direction Y, and transmit the images to the image processing device 18. As shown in Figures 2 and 3, the imaging devices 16a, 16b include a first imaging device 16a that images a first end GRa of the glass ribbon GR, and a second imaging device 16b that images a second end GRb of the glass ribbon GR.

[0045] As shown in FIG. 3 , the first imaging device 16a is arranged more inward than the first end portion GRa in the width direction X of the glass ribbon GR. Furthermore, the first imaging device 16a is arranged in an inclined position with respect to the thickness direction T of the glass ribbon GR so as to capture an image of a detection position DP of the first end portion GRa of the glass ribbon GR that is positioned more outward than the first imaging device 16a in the width direction X. The inclination angle θ1 of the first imaging device 16a with respect to the thickness direction T of the glass ribbon GR is 1° or more and 45° or less. Note that the first imaging device 16a may be arranged more outward than the first end portion GRa in the width direction X of the glass ribbon GR. From the viewpoint of securing installation space without increasing the size of the annealing furnace 3, it is preferable that the first imaging device 16a be arranged more inward than the first end portion GRa in the width direction X of the glass ribbon GR.

[0046] As shown in FIG. 3 , the second imaging device 16b is arranged more inward than the second end portion GRb in the width direction X of the glass ribbon GR. Furthermore, the second imaging device 16b is arranged in an inclined position with respect to the thickness direction T of the glass ribbon GR so as to capture an image of a detection position DP of the second end portion GRb of the glass ribbon GR located more outward in the width direction X than the second imaging device 16b. The inclination angle θ2 of the second imaging device 16b with respect to the thickness direction T of the glass ribbon GR is equal to or greater than 1° and equal to or less than 45°. Note that the second imaging device 16b may be arranged more outward than the second end portion GRb in the width direction X of the glass ribbon GR. From the viewpoint of securing installation space without increasing the size of the annealing furnace 3, it is preferable that the second imaging device 16b be arranged more inward than the second end portion GRb in the width direction X of the glass ribbon GR.

[0047] The arrangement of the imaging devices 16a, 16b is not limited to the embodiment shown in Fig. 3. For example, as shown in Fig. 4, the first imaging device 16a and the second imaging device 16b may be arranged in an orientation parallel to the thickness direction T of the glass ribbon GR. In this case, the first illumination device 17a may be arranged in an inclined orientation outward from the first imaging device 16a in the width direction X, and the second illumination device 17b may be arranged in an inclined orientation outward from the second imaging device 16b in the width direction X. From the viewpoint of ensuring installation space without increasing the size of the annealing furnace 3, it is preferable that the first illumination device 17a be arranged in an inclined orientation inward from the first imaging device 16a in the width direction X, and the second illumination device 17b be arranged in an inclined orientation inward from the second imaging device 16b in the width direction X.

[0048] 1 and 2, the illumination devices 17a and 17b are disposed below the annealing furnace 3. The illumination devices 17a and 17b include a first illumination device 17a used for imaging by the first imaging device 16a and a second illumination device 17b used for imaging by the second imaging device 16b.

[0049] 3, the first lighting device 17a and the second lighting device 17b each include a plurality of illumination devices. That is, each of the illumination devices 17a and 17b includes an illumination device arranged on the first main surface GR1 side of the glass ribbon GR and irradiating light L toward the first main surface GR1, and an illumination device arranged on the second main surface GR2 side of the glass ribbon GR and irradiating light L toward the second main surface GR2.

[0050] 1, each of the illumination devices 17a and 17b is disposed so as to irradiate light L in the horizontal direction. However, each of the illumination devices 17a and 17b may be configured to irradiate light L obliquely downward, similar to each of the imaging devices 16a and 16b.

[0051] 3, each of the illumination devices 17a, 17b is disposed so as to irradiate light L along the thickness direction T of the glass ribbon GR. The first illumination device 17a is disposed further outward in the width direction X than the first imaging device 16a. The second illumination device 17b is disposed further outward in the width direction X than the second imaging device 16b.

[0052] The image processing device 18 can detect the positions of the ends GRa and GRb of the glass ribbon GR based on the images captured by the imaging devices 16a and 16b. The image processing device 18 is a computer having built-in image analysis software. The image processing device 18 includes a monitor that displays the images transmitted from the imaging devices 16a and 16b.

[0053] 5 and 6 schematically show images displayed on the monitor of the image processing device 18. The examples of Fig. 5 and Fig. 6 illustrate an image 19 including the second end portion GRb of the glass ribbon GR. This image 19 includes the ear portion TP at the second end portion GRb of the glass ribbon GR and a non-effective portion formed integrally with the ear portion TP.

[0054] The image processing device 18 can display the measurement areas 20 superimposed within the range of the image 19. As shown in Fig. 5, one measurement area 20 displayed on the image 19 is configured as a rectangular frame along the width direction X. The image processing device 18 can detect the positions of the ends GRa and GRb of the glass ribbon GR and the width W of the edge portions TP within the range of the measurement area 20 (inside the frame).

[0055] Specifically, the image processing device 18 detects the positions of the edges TPa and TPb of the ear TP that are captured within the measurement area 20. The edges TPa and TPb of the ear TP include a first edge TPa located on the outer side in the width direction X and a second edge TPb located on the inner side in the width direction X of the first edge TPa. The image processing device 18 detects the position of the first edge TPa within the measurement area 20 as the position of the second end GRb. Furthermore, by detecting the positions of the first edge TPa and the second edge TPb, the image processing device 18 can detect the distance in the width direction X between the first edge TPa and the second edge TPb, i.e., the width W of the ear TP.

[0056] In the example shown in Figure 6, two measurement areas 20a and 20b are included in image 19. Hereinafter, one of the two measurement areas 20a and 20b will be referred to as the first measurement area 20a, and the other will be referred to as the second measurement area 20b. The first measurement area 20a can detect the position of a first edge portion TPa of the ear portion TP. The second measurement area 20b can detect the position of a second edge portion TPb of the ear portion TP.

[0057] The edge rollers 8a, 8b of the forming device 6, the conveying rollers 13a, 13b of the annealing furnace 3, and the support rollers 14a, 14b of the cooling zone 4 constitute a conveying device that conveys the glass ribbon GR in the longitudinal direction Y.

[0058] 1, the cutting device 5 is provided below the cooling zone 4. The cutting device 5 includes a scribing device (not shown), a contact unit 21, and a stress applying unit 22.

[0059] The scribing device forms a scribe line SL on the first main surface GR1 of the glass ribbon GR along the width direction X. The scribing device includes, for example, a wheel cutter for forming the scribe line SL. The scribing device is not limited to the wheel cutter, and may also form the scribe line SL by another method such as laser irradiation.

[0060] The contact portion 21 supports the second main surface GR2 of the glass ribbon GR at a position corresponding to the scribe line SL. The contact portion 21 is composed of a plate-like body (surface plate) having a contact surface that comes into contact with the second main surface GR2 of the glass ribbon GR along the width direction X of the glass ribbon GR while descending following the glass ribbon GR during its descent.

[0061] The stress applying unit 22 holds a portion of the glass ribbon GR corresponding to the glass plate GF to be cut out (a portion below the scribe line SL) and applies bending stress to the scribe line SL. The stress applying unit 22 includes gripping units (e.g., chucks) that grip the ends GRa, GRb of the glass ribbon GR.

[0062] The following describes a method for manufacturing a glass plate GF as a glass article using the manufacturing apparatus 1 configured as described above. As shown in Fig. 7, this method includes a forming step S1, an annealing step S2, a cooling step S3, and a cutting step S4.

[0063] 1, in the forming step S1, a glass ribbon GR is continuously formed from molten glass GM by a forming device 6. The forming body 7 causes the molten glass GM to overflow from an overflow groove 9 and flow down along side wall surfaces 10 and 11 on both sides of the forming body 7.

[0064] Furthermore, the forming body 7 fuses (merges) the molten glass GM that has flowed down at the lower end 12. This forms a glass ribbon GR having a predetermined width. The edge rollers 8a, 8b feed the glass ribbon GR downward while clamping the ends GRa, GRb of the glass ribbon GR with a predetermined pressure so as to suppress shrinkage of the glass ribbon GR in the width direction X.

[0065] In the annealing step S2, the glass ribbon GR is conveyed downward by conveying rollers 13a and 13b in the annealing furnace 3. A predetermined temperature gradient is set in the annealing furnace 3, and the glass ribbon GR is annealed by passing through the annealing furnace 3.

[0066] In the cooling step S3 after the slow cooling step S2, the glass ribbon GR passes through the cooling zone 4 while being conveyed in the longitudinal direction Y while being tensioned by the support rollers 14a, 14b, and is cooled to near room temperature.

[0067] During the cooling step S3, an inspection step is carried out to inspect the position of the glass ribbon GR passing through the cooling zone 4. As shown in Fig. 8, the inspection step includes an imaging step S31, a detection step S32, and a determination step S33.

[0068] In the imaging step S31, the glass ribbon GR is transported in the longitudinal direction Y while the imaging devices 16a and 16b image the ends GRa and GRb of the glass ribbon GR to obtain the images 19. Also in the imaging step S31, the illumination devices 17a and 17b irradiate the ends GRa and GRb of the glass ribbon GR with light L.

[0069] The imaging step S31 is performed so that the edge portions TP of the ends GRa, GRb of the glass ribbon GR can be easily detected in the acquired image 19 in the subsequent detection step S32. That is, by arranging the positions and attitudes of the imaging devices 16a, 16b and the irradiation angles of the light L from the lighting devices 17a, 17b in the manner described with reference to Fig. 3 or Fig. 4, the positions of the edge portions TPa, TPb of the edge portions TP become dark or black, for example. Note that it is presumed that the reason the positions of the edge portions TPa, TPb of the edge portions TP become dark or black is due to light reflection or shadows formed by the unevenness of the edge portions TP.

[0070] In the detection step S32, the image processing device 18 detects the positions of the ends GRa, GRb of the glass ribbon GR (the position of the first edge portion TPa of the ear portion TP) based on the image 19 captured in the imaging step S31. Furthermore, the image processing device 18 detects the width W of the ear portion TP at each end GRa, GRb of the glass ribbon GR based on the image 19 of the glass ribbon GR received from the imaging devices 16a, 16b.

[0071] In the detection step S32, the image processing device 18 detects the position and width W of the edge portion TP based on one or more of the hue, saturation, and brightness of each end portion GRa, GRb of the glass ribbon GR included in the image 19. That is, as shown in FIGS. 5 and 6, in the image 19 captured in the imaging step S31, the first edge portion TPa and the second edge portion TPb of the edge portion TP at each end portion GRa, GRb are displayed in low-brightness black. In contrast, the portions of the edge portion TP other than the edge portions TPa, TPb are displayed in high-brightness. The image processing device 18 can accurately detect the position and width W of each edge portion TPa, TPb of the edge portion TP based on these black portions.

[0072] In the determination step S33, the quality of the positions of the ends GRa, GRb of the glass ribbon GR is determined by the image processing device 18. In the determination step S33, when the positions of the ends GRa, GRb of the glass ribbon GR exceed a reference value, the image processing device 18 determines that excessive positional deviation has occurred in the glass ribbon GR.

[0073] In addition, in a determination step S33, the image processing device 18 determines whether the edge portions TP of each end portion GRa, GRb of the glass ribbon GR are good or bad. That is, the image processing device 18 compares the width W of the detected edge portions TP with reference values (threshold values). The reference values include a first reference value that is the maximum allowable value for the width W of the edge portions TP and a second reference value that is the minimum allowable value for the width W of the edge portions TP.

[0074] The image processing device 18 compares the detected width W of the selvage portion TP with a first reference value. If the width W of the selvage portion TP exceeds the first reference value, the image processing device 18 determines that the width W of the selvage portion TP is abnormal. The image processing device 18 compares the detected width W of the selvage portion TP with a second reference value. If the width W of the selvage portion TP is less than the second reference value, the image processing device 18 determines that the width W of the selvage portion TP is abnormal. The image processing device 18 can display the determination result (normal or abnormal) on a monitor.

[0075] This method includes a countermeasure process for changing the conditions of the forming process S1 and / or the slow cooling process S2 when a positional abnormality (excessive positional deviation) in the glass ribbon GR or an abnormality in the width W of the edge portion TP is detected in the judgment process S33.

[0076] For example, in the countermeasure process, the position of the glass ribbon GR is adjusted using a conveying device (edge rollers 8a, 8b, conveying rollers 13a, 13b, support rollers 14a, 14b) to eliminate the positional deviation caused by the detected meandering of the glass ribbon GR and return the glass ribbon GR to the desired position.

[0077] Specifically, the countermeasures include adjusting the rotation speed of the edge rollers 8a, 8b and adjusting the clamping pressure of the glass ribbon GR by the edge rollers 8a, 8b, adjusting the rotation speed of the conveying rollers 13a, 13b in the annealing furnace 3 and adjusting the clamping pressure of the glass ribbon GR by the conveying rollers 13a, 13b, or adjusting the rotation speed of the support rollers 14a, 14b in the cooling zone 4 and adjusting the clamping pressure of the glass ribbon GR by the support rollers 14a, 14b.

[0078] Hereinafter, the detection step S32, the determination step S33, and the handling step will be described in detail using as an example a case where the second end portion GRb of the glass ribbon GR has moved outward X1 in the width direction X as shown in Fig. 5. As shown in Fig. 5, when the second end portion GRb of the glass ribbon GR has moved from the appropriate position indicated by the solid line to the position indicated by the two-dot chain line, the image processing device 18 calculates the movement distance D of this second end portion GRb (detection step S32).

[0079] Thereafter, the image processing device 18 starts the determination step S33 and compares the calculated movement distance D of the second end portion GRb with a reference value (threshold value). When the movement distance D of the second end portion GRb exceeds the reference value, the image processing device 18 determines that an abnormal positional deviation has occurred in the glass ribbon GR.

[0080] When this abnormal positional deviation of the glass ribbon GR is detected, the manager of the manufacturing apparatus 1 executes a countermeasure step to return the position of the glass ribbon GR to an appropriate position. This is not limitative, and the countermeasure step may be executed by automatic control using a control device. In the countermeasure step, the following processing is performed to return the glass ribbon GR that has moved outward X1 in the width direction X to its original appropriate position.

[0081] For example, in the countermeasure step, the manufacturing apparatus 1 increases the rotation speeds of the first edge roller 8a, the first conveying roller 13a, and the first support roller 14a. As a result, the glass ribbon GR is drawn toward the first edge roller 8a, the first conveying roller 13a, and the first support roller 14a. As another process, the manufacturing apparatus 1 increases the clamping pressure of the glass ribbon GR by the first edge roller 8a, the first conveying roller 13a, and the first support roller 14a. As a result, the glass ribbon GR is drawn toward the first edge roller 8a, the first conveying roller 13a, and the first support roller 14a. In this way, the glass ribbon GR that has moved excessively outward X1 in the width direction X can be drawn back to its original appropriate position.

[0082] The cutting step S4 is a step of cutting out a glass sheet GF from the glass ribbon GR after the cooling step S3. The cutting step S4 includes a first cutting step and a second cutting step. In the first cutting step, a cutting device 5 cuts a middle portion of the glass ribbon GR along the width direction X to cut out a glass sheet GF of a predetermined size. That is, in the first cutting step, a scribe line SL is formed along the width direction X by a scribing device in a middle portion of the glass ribbon GR moving downward (scribing step), and a portion of the glass ribbon GR is bent and split along the scribe line SL to form a sheet-shaped glass sheet GF (bending and splitting step).

[0083] In the scribing process, the wheel cutter of the scribing device descends, following the glass ribbon GR as it descends, and forms a scribe line SL in the width direction X of the glass ribbon GR. In the bending and splitting process, the stress applying unit 22 descends, following the glass ribbon GR as it descends, and performs an operation to bend the glass ribbon GR with the contact unit 21 as a fulcrum. This operation of the stress applying unit 22 applies a bending stress to the scribe line SL. As a result, the glass ribbon GR is bent and split in the width direction X along the scribe line SL, and a glass plate GF is cut out from the glass ribbon GR.

[0084] In the second cutting step, widthwise ends of the glass plate GF corresponding to the ends GRa and GRb of the glass ribbon GR are cut and removed by a cutting device (not shown), thereby forming a rectangular glass plate GF.

[0085] According to the glass article manufacturing apparatus 1 and manufacturing method of this embodiment described above, the positions of each end GRa, GRb of the glass ribbon GR can be detected by the detection process S32 (image processing device 18) based on the images 19 of each end GRa, GRb of the glass ribbon GR acquired by the imaging process S31 (imaging devices 16a, 16b).

[0086] As a result, when a positional deviation occurs in the glass ribbon GR during conveyance, this positional deviation can be detected from a change in the positions of the ends GRa and GRb of the glass ribbon GR. By detecting an abnormality in the conveyance of the glass ribbon GR in this manner, it is possible to detect a quality abnormality due to a change in the warp or distortion of the glass ribbon GR at an early stage, and to take appropriate action to resolve the abnormality.

[0087] The present invention is not limited to the configuration of the above-described embodiment, nor is it limited to the above-described effects. The present invention can be modified in various ways without departing from the spirit of the present invention.

[0088] In the above embodiment, a method for manufacturing a glass sheet GF by cutting the glass ribbon GR has been described, but the present invention is not limited to this example. For example, the present invention is also applicable to a case where a glass roll is manufactured by winding the glass ribbon GR into a roll.

[0089] In the above embodiment, an example of manufacturing a glass article by the overflow downdraw method has been described, but the present invention is not limited to this. For example, the present invention can also manufacture a glass article by the slot downdraw method.

[0090] In the above embodiment, an example has been shown in which the imaging step S31 is performed by the imaging devices 16a, 16b and the lighting devices 17a, 17b provided in the cooling zone 4, but the present invention is not limited to this configuration. The imaging step S31 may also be performed by the imaging devices 16a, 16b and the lighting devices 17a, 17b provided in the annealing furnace 3. Alternatively, the imaging step S31 may also be performed by the imaging devices 16a, 16b and the lighting devices 17a, 17b provided between the cooling zone 4 and the cutting device 5. [Explanation of symbols]

[0091] 1. Glass product manufacturing equipment 3 Annealing furnace 6 Molding equipment 8a First edge roller (conveyor device) 8b Second edge roller (conveyor device) 13a First conveying roller (conveying device) 13b Second conveying roller (conveying device) 14a First support roller (conveyor device) 14b Second support roller (conveyor device) 16a First imaging device 16b Second imaging device 17a First lighting device 17b Second lighting device 18 Image processing device 19 images GM Molten Glass GR Glass Ribbon GRa First end of glass ribbon GRb Second end of glass ribbon L Light from lighting equipment S1 Molding process S2 slow cooling process S3 cooling process S4 Cutting process S31 Imaging process S32 Detection process S33 Judgment process TP ears X: Width direction of the glass ribbon Y vertical direction W Width of ear

Claims

1. A method for manufacturing a glass article, comprising: a forming step of forming a glass ribbon from molten glass; and an annealing step of annealing the formed glass ribbon in an annealing furnace while conveying the formed glass ribbon in a vertical direction, A method for manufacturing a glass article, comprising: an imaging step of imaging an end portion in a width direction of the glass ribbon while transporting the glass ribbon in a vertical direction; and a detection step of detecting the position of the end portion of the glass ribbon based on the image captured in the imaging step.

2. The method for manufacturing a glass article according to claim 1 , wherein in the imaging step, light is irradiated onto the end portion of the glass ribbon by an illumination device.

3. 3. The method for manufacturing a glass article according to claim 1 or 2, wherein the detection step uses an image processing device to detect the position of the end portion based on one or more of the hue, saturation, and brightness of the end portion of the glass ribbon contained in the image.

4. The method for manufacturing a glass article according to claim 1 or 2, wherein the detection step detects a width of an edge portion included in the end portion of the glass ribbon based on the image captured in the imaging step.

5. The method for manufacturing a glass article according to claim 4, wherein the detection step uses an image processing device to detect the width of the ear portion based on one or more of the hue, saturation, and brightness of the end portion of the glass ribbon contained in the image.

6. The method for manufacturing a glass article according to claim 1 or 2, wherein the imaging step is carried out below the annealing furnace.

7. a cooling step of cooling the glass ribbon that has been subjected to the annealing step while conveying it in a vertical direction; and a cutting step of cutting a glass sheet from the glass ribbon after the cooling step, The method for manufacturing a glass article according to claim 1 or 2, wherein the imaging step is carried out during the cooling step.

8. A determination step of determining whether the position of the end of the glass ribbon is good or bad, In the determination step, when a position of the end portion of the glass ribbon exceeds a reference value, it is determined that an excessive positional deviation has occurred in the glass ribbon, The method for manufacturing a glass article according to claim 1 or 2, further comprising a countermeasure step of changing conditions for the forming step and / or the annealing step when excessive misalignment of the glass ribbon is determined.

9. An apparatus for manufacturing a glass article, comprising: a forming device that forms a glass ribbon from molten glass; a conveying device that conveys the glass ribbon in a vertical direction; and an annealing furnace that anneals the glass ribbon conveyed by the conveying device, A glass article manufacturing apparatus comprising: an imaging device that images the widthwise end of the glass ribbon transported by the transport device; and an image processing device that detects the position of the end of the glass ribbon based on the image captured by the imaging device.

Images