Method for manufacturing glass article

Abstract

To quickly remove a defect crack from a glass ribbon when causing the defect crack in the glass ribbon while manufacturing a glass article based on a glass ribbon.SOLUTION: A method for manufacturing a glass article comprises: a conveying step P4 of conveying a glass ribbon G along a conveying path 11; an acquisition step P5 of acquiring a glass plate Gs from the glass ribbon G at the downstream end 11e of the conveying path 11; and a guidance step P6 of guiding a defect crack C to the edge Ge of the glass ribbon G in the width direction when the defect crack C progressing toward the upstream side of the glass ribbon G is caused in the glass ribbon G. The guidance step P6 provides a tension difference between the one and other side parts G1 and G2 of the glass ribbon G separated using the defect crack C as a boundary in the width direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a glass article. [Background technology]

[0002] Glass articles such as glass sheets and glass rolls are often manufactured from glass ribbons. Patent Document 1 discloses an example of a method for manufacturing a glass roll from a glass ribbon.

[0003] In this embodiment, first, a glass ribbon is continuously formed from molten glass using a down-draw method. Next, the conveying direction of the formed glass ribbon is changed from the vertical direction to the horizontal direction. After that, unnecessary portions present on one side and the other side in the width direction of the glass ribbon are cut and removed from the glass ribbon. Finally, the glass ribbon from which the unnecessary portions have been removed is wound into a roll around a winding core to form a glass roll. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-40755 Summary of the Invention [Problem to be solved by the invention]

[0005] When manufacturing glass articles from a glass ribbon as described above, production losses of glass articles may occur due to cracks that unintentionally occur in the glass ribbon (hereinafter referred to as "defective cracks").

[0006] For example, as in the embodiment shown in Fig. 6, when the glass ribbon 100 transported in the A direction is repeatedly cut at the downstream end of the transport path to continuously cut out glass sheets 200 from the glass ribbon 100, production loss may occur. In this embodiment, if the cutting of the glass sheet 200 fails, the glass ribbon 100 may break, causing a defective crack C. The defective crack C propagates toward the upstream side (direction B) of the glass ribbon 100, opposite to the transport direction (direction A) of the glass ribbon 100. Note that one side portion 101 and the other side portion 102 in the width direction of the glass ribbon 100 shown in the figure are separated at the defective crack C as a boundary.

[0007] When the above-mentioned defective crack C occurs, it becomes impossible to cut out a new glass sheet 200 from the glass ribbon 100 until the defective crack C is removed from the glass ribbon 100. In detail, the defective crack C does not stop progressing upstream and continues to exist on the glass ribbon 100 unless the defective crack C is deflected to the width-direction edge 100a of the glass ribbon 100. Therefore, the cutting out of the glass sheet 200 has to be stopped until the defective crack C accidentally deflects to the width-direction edge 100a. This causes a production loss of the glass sheet 200. Therefore, it has been expected to establish a technology that can quickly remove the defective crack C from the glass ribbon 100 when the defective crack C occurs in the glass ribbon 100.

[0008] In view of the above circumstances, a technical problem to be solved is to be able to quickly remove defective cracks from a glass ribbon when the defective cracks occur in the glass ribbon when a glass article is manufactured from the glass ribbon. [Means for solving the problem]

[0009] A first glass article manufacturing method for solving the above problem is a glass article manufacturing method comprising a conveying step of conveying a glass ribbon along a conveying path, and an acquisition step of acquiring a glass article from the glass ribbon at a downstream end of the conveying path, and further comprising an guiding step of guiding a defective crack that propagates toward the upstream side of the glass ribbon to a widthwise edge of the glass ribbon when the defective crack occurs in the glass ribbon, and is characterized in that in the guiding step, a tension difference is provided between the tension generated in one side portion of the glass ribbon in the widthwise direction and the tension generated in the other side portion separated by the defective crack.

[0010] In the first glass article manufacturing method, as the induction step is performed, a tension difference occurs between the tension generated in one side region of the glass ribbon in the width direction and the tension generated in the other side region separated by the defective crack (hereinafter, the region with the greater tension of the two regions will be referred to as the "high tension region"). Due to the occurrence of this tension difference, the defective crack advances toward one of both width direction end edges of the glass ribbon that is included in the high tension region, and quickly reaches that end edge. As a result, the defective crack can be removed from the glass ribbon. As such, according to this manufacturing method, when a defective crack occurs in the glass ribbon, it becomes possible to quickly remove the defective crack from the glass ribbon.

[0011] The second method for manufacturing a glass article is the same as the first manufacturing method described above, except that in the induction process, a tension difference is created by accelerating the conveying speed of one of the one-side portions and the other-side portion.

[0012] In the second method for producing a glass article, the tension difference is created by accelerating the conveying speed of one of the two sections, so that the tension difference can be created quickly and reliably between the two sections. In addition, since the conveying speed is accelerated, unlike the case where the conveying speed is decelerated, the risk of wrinkles or slackness occurring in the glass ribbon due to the execution of the guiding step can be eliminated.

[0013] The third method for manufacturing a glass article is the above-mentioned first or second manufacturing method, wherein in the induction process, a tension difference is created by applying to one of the one side portion and the other side portion (1) an external force directed downstream in the conveying direction of the glass ribbon, or (2) an external force having a component directed downstream in the conveying direction of the glass ribbon and a component directed from the center toward the outside in the width direction.

[0014] In the third method for producing a glass article, the above-mentioned external force (1) or (2) is applied to one of the two regions. Both of the external forces (1) and (2) have a component directed toward the downstream side in the conveying direction of the glass ribbon. This has the effect of reliably creating a tension difference between the two regions by applying the external force, and the effect of making it easier for bad cracks to progress toward the widthwise edge of the glass ribbon.

[0015] A fourth method for manufacturing a glass article is the same as the third manufacturing method described above, except that an external force is applied to a portion of the glass ribbon located between a widthwise edge of the glass ribbon and a defective crack.

[0016] In the fourth method for producing a glass article, an external force is applied to a portion of the glass ribbon that is on the inside of the widthwise edge. Therefore, it is possible to avoid a load being applied to the widthwise edge, which is a portion of the glass ribbon that has low strength, during the guiding step. Therefore, it is possible to eliminate the risk of new defective cracks being generated from the widthwise edge to which the load is applied.

[0017] The fifth method for manufacturing a glass article is the third or fourth manufacturing method described above, except that an external force is applied to the area having the smaller width dimension between the one side area and the other side area.

[0018] In the fifth method for producing a glass article, the defective crack propagates toward one of both widthwise edges of the glass ribbon that is closer to the defective crack, which shortens the time required for the defective crack to reach the widthwise edge, and enables the defective crack to be removed from the glass ribbon more quickly.

[0019] The sixth method for manufacturing a glass article is any one of the third to fifth manufacturing methods described above, in which, when applying an external force, a feed member having a feed direction that is the same as the direction of the external force is brought into contact with the glass ribbon.

[0020] In the sixth method for producing a glass article, an external force is applied by bringing the feed member into contact with the glass ribbon, so that the external force can be applied stably.

[0021] The seventh method for producing a glass article is the same as the sixth method, except that the feed member is a roller.

[0022] In the seventh method for producing a glass article, since a roller is used as the feed member, it becomes possible to realize the application of an external force with a simple configuration.

[0023] An eighth method for producing a glass article is the above-mentioned seventh production method, except that the peripheral speed of the roller is made faster than the conveying speed of the glass ribbon when the roller comes into contact with the glass ribbon.

[0024] In the eighth method for producing a glass article, an external force can be applied by the frictional force between the peripheral surface of the roller and the surface of the glass ribbon (one of the one side portion and the other side portion).

[0025] A ninth method for manufacturing a glass article is any one of the third to fifth manufacturing methods described above, in which the external force is applied by spraying a gas toward the glass ribbon.

[0026] In the ninth method of manufacturing a glass article, an external force is applied by spraying gas, making it easy to apply an external force even if the width dimension of the area to which the external force is to be applied (one of the one side area and the other side area) is small.

[0027] A tenth method for manufacturing a glass article is any one of the first to ninth manufacturing methods described above, in which in the induction process, the glass ribbon is photographed to obtain an image, and the image is processed to detect the occurrence of defective cracks.

[0028] In the tenth method for manufacturing a glass article, images of a glass ribbon are captured and image processing is used, so that defective cracks occurring in the glass ribbon can be detected with high accuracy.

[0029] An eleventh method for manufacturing a glass article is any one of the first to tenth manufacturing methods described above, in which the obtaining process involves repeatedly cutting the glass ribbon in the width direction to continuously obtain glass plates as the glass article.

[0030] In the eleventh method for producing a glass article, the glass ribbon is repeatedly cut in the width direction, and therefore defective cracks are likely to occur at the ends (cut ends) formed in the glass ribbon as a result of cutting. Therefore, in this production method, it is possible to preferably enjoy the effect of being able to quickly remove defective cracks from the glass ribbon.

[0031] A twelfth method for manufacturing a glass article is a method in which, in any one of the first to eleventh manufacturing methods described above, the glass ribbon has a thickness of 200 μm or less, and is subjected to a forming process, a conveying direction changing process after the forming process, and a process of cutting off unnecessary parts after the conveying direction changing process, and then is subjected to a conveying process, in which in the forming process, the glass ribbon is formed while being drawn out in the vertical direction from the molten glass supplied to the forming body, in the conveying direction changing process, the conveying direction of the glass ribbon after the forming process is changed from the vertical direction to the horizontal direction, and in the unnecessary part cutting process, the unnecessary parts present on one side and the other side of the width direction of the glass ribbon are cut and removed from the glass ribbon.

[0032] In the twelfth method for producing a glass article, the thickness of the glass ribbon is extremely thin, at 200 μm or less, and an unnecessary portion cutting step is performed, so that defective cracks are likely to occur in the glass ribbon that has been subjected to the unnecessary portion cutting step. Therefore, in this production method, it is possible to more suitably enjoy the effect of being able to quickly remove defective cracks from the glass ribbon.

[0033] A thirteenth method for manufacturing a glass article for solving the above problem is a method for manufacturing a glass article comprising a conveying step of conveying a glass ribbon along a conveying path, and an acquiring step of acquiring a glass article from the glass ribbon at a downstream end of the conveying path, and further comprising a guiding step of guiding a defective crack that propagates toward the upstream side of the glass ribbon to a widthwise edge of the glass ribbon when the defective crack occurs in the glass ribbon, and is characterized in that in the guiding step, an external force for guiding is applied to one of one side portion and the other side portion in the widthwise direction of the glass ribbon separated by the defective crack as a boundary.

[0034] In the thirteenth method for manufacturing a glass article, it is possible to obtain the same functions and effects as in the first manufacturing method described above. Effect of the Invention

[0035] According to the method for manufacturing a glass article according to the present disclosure, when a glass article is manufactured from a glass ribbon, if a defective crack occurs in the glass ribbon, it is possible to quickly remove the defective crack from the glass ribbon. [Brief description of the drawings]

[0036] [Figure 1] FIG. 2 is a side view showing a method for manufacturing a glass article. [Diagram 2] FIG. 2 is a plan view showing a method for manufacturing a glass article. [Diagram 3] FIG. [Figure 4] FIG. 4(a) is a plan view showing the guiding step, and FIG. 4(b) is a side view showing the guiding step. [Diagram 5]FIG. 11 is a side view showing a modified example of the guiding step. [Figure 6] FIG. 11 is a plan view for explaining a problem in the conventional art. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Hereinafter, a method for manufacturing a glass article according to an embodiment will be described with reference to the accompanying drawings. Note that the X direction, Y direction, and Z direction shown in each drawing referred to in the description of the embodiment are directions perpendicular to each other.

[0038] 1 and 2, in the method for manufacturing a glass article according to this embodiment, a glass sheet Gs as a glass article is cut out from a glass ribbon G formed using a downdraw method (overflow downdraw method in the illustrated example). This manufacturing method includes, as main steps, a forming step P1, a conveying direction changing step P2, an unnecessary part cutting step P3, a conveying step P4, and an obtaining step P5.

[0039] In the forming step P1, a glass ribbon G is formed while being drawn out in the vertical direction (Z direction) from the molten glass MG supplied to the forming body 1. A roller group 2 arranged in multiple stages vertically is used for drawing out the glass ribbon G. The roller group 2 includes edge rollers 3, annealer rollers 4, and support rollers 5.

[0040] The edge rollers 3 contact the width direction ends of the glass ribbon G directly below the forming body 1 to suppress shrinkage of the glass ribbon G in the width direction (X direction). The annealer rollers 4 guide the downward movement of the glass ribbon G which is slowly cooled to a temperature below the strain point in an annealing furnace (not shown). The support rollers 5 support and pull downward the glass ribbon G whose temperature has been reduced to near room temperature in a cooling chamber (not shown).

[0041] An unnecessary portion Gx is present on each of one and the other sides in the width direction of the formed glass ribbon G (in FIG. 2, the boundary between the unnecessary portion Gx and other portions is indicated by a two-dot chain line). The unnecessary portion Gx is a portion that is cut off and removed from the glass ribbon G in an unnecessary portion cutting process P3 that is executed downstream of the forming process P1. The unnecessary portion Gx includes an edge portion that is thicker than other portions of the glass ribbon G. The thickness of the glass ribbon G (the thickness of the portion excluding the edge portion) is, for example, 200 μm or less, 100 μm or less, or 50 μm or less.

[0042] In the conveying direction changing step P2, the conveying direction of the glass ribbon G after the forming step P1 is changed from the vertical direction to the horizontal direction (Y direction). To change the conveying direction of the glass ribbon G, a roller conveyor 6 consisting of a plurality of rollers is used.

[0043] The glass ribbon G after the conveying direction changing step P2 is conveyed downstream by a belt conveyor 7 and a strip-shaped protective sheet 9 (for example, a strip-shaped resin sheet) moving on a support table 8, and sent to an unnecessary portion cutting step P3.

[0044] In the unnecessary portion cutting process P3, the unnecessary portion Gx is cut and removed from the glass ribbon G. A laser cutting device 10 is used to cut off the unnecessary portion Gx. A laser L is irradiated from the device 10 toward the glass ribbon G, and the unnecessary portion Gx is cut off by continuously cutting the glass ribbon G along the longitudinal direction (Y direction). The unnecessary portion Gx after cutting is separated from the conveying path 11 of the glass ribbon G downstream of the unnecessary portion cutting process P3 and discarded.

[0045] In the conveying step P4, the glass ribbon G after the unnecessary portion cutting step P3 (the glass ribbon G from which the unnecessary portion Gx has been removed) is conveyed along a conveying path 11 and sent to an obtaining step P5. A strip-shaped protective sheet 9 moving on a belt conveyor 12 and a board 13 is used to convey the glass ribbon G in the conveying step P4.

[0046] Above the transport path 11 for the glass ribbon G, an imaging device 14 and a pair of rollers 15, 15 (feeding members) used in a guiding step P6 described later are disposed.

[0047] The pair of rollers 15, 15 are disposed corresponding to one side and the other side in the width direction of the glass ribbon G, respectively. Each roller 15 is located between the width direction center and the width direction edge Ge of the glass ribbon G when viewed from the Z direction. Both of the pair of rollers 15, 15 are located above the board 13. Each roller 15 can move in the vertical direction, and can contact and separate from the surface of the glass ribbon G as it moves. Each roller 15 contacts the surface of the glass ribbon G when used in the guiding step P6, and separates from the surface when not in use. The function of the imaging device 14 and the operation of the pair of rollers 15, 15 in the guiding step P6 will be described in detail later.

[0048] In the obtaining step P5, the glass ribbon G is repeatedly cut in the width direction (X direction) at the downstream end 11e of the conveying path 11 to obtain glass sheets Gs continuously from the glass ribbon G. The cutting of the glass ribbon G in the width direction can be performed by a known cutting device or by cutting work by an operator. The multiple glass sheets Gs obtained from the glass ribbon G are packaged after being alternately stacked with, for example, buffer sheets.

[0049] In addition to the above-mentioned steps P1 to P5, this manufacturing method further includes an induction step P6 shown in FIGS.

[0050] The guiding process P6 is a process executed when a defective crack C that progresses toward the upstream side (D1 direction) of the glass ribbon G occurs, as shown in FIG. 3. In the guiding process P6, the defective crack C is guided to the widthwise edge Ge of the glass ribbon G, and the defective crack C is removed from the glass ribbon G accordingly. In this embodiment, a case where a defective crack C occurs from a cut end (a leading end of the glass ribbon G) when the glass ribbon G is cut in the width direction in the obtaining process P5 is taken as an example. During the execution of the guiding process P6, the execution of the obtaining process P5 is interrupted to stop the acquisition of the glass sheet Gs from the glass ribbon G. During the execution of the guiding process P6, the glass ribbon G that has reached the downstream end 11e of the conveying path 11 is continuously discarded.

[0051] The defective crack C is a crack that propagates in the opposite direction to the conveying direction of the glass ribbon G. When this defective crack C occurs in the glass ribbon G, one side region G1 and the other side region G2 in the width direction of the glass ribbon G, which are separated by the defective crack C, are separated. In this embodiment, as one occurrence mode of the defective crack C, the defective crack C occurs near one side in the width direction of the glass ribbon G. As a result, the width dimension W1 of the one side region G1 is smaller than the width dimension W2 of the other side region G2. Of course, there are also cases where the defective crack C occurs near the center in the width direction of the glass ribbon G (cases where W1 and W2 are approximately the same dimension).

[0052] In the induction process P6, it is first necessary to detect the occurrence of a defective crack C in the glass ribbon G. To detect the defective crack C, an imaging device 14 that images the glass ribbon G and an image processing device (not shown) that processes the captured image are used.

[0053] The imaging device 14 has a field of view that covers a predetermined range in the X direction and the Y direction. In the X direction, the field of view covers the entire width of the glass ribbon G after the unnecessary portion cutting process P3 (the entire width after the unnecessary portion Gx is cut off). In the Y direction, the field of view covers at least a portion of the longitudinal section of the glass ribbon G. This allows the imaging device 14 to reliably capture the defective crack C in its field of view when the defective crack C occurs in the glass ribbon G, regardless of the position where the defective crack C occurs in the width direction (whether toward one side or the other side in the width direction).

[0054] The image processing device can detect the defective crack C by, for example, using a differential image (imaging the difference in pixel values ​​between the captured image and an image captured in the past) based on the image captured by the imaging device 14. Of course, other image processing may be used to detect the defective crack C as long as the presence or absence of the defective crack C can be determined.

[0055] When occurrence of a bad crack C in the glass ribbon G is detected, the bad crack C is guided to the widthwise edge Ge of the glass ribbon G, as shown in Fig. 4(a). To guide the bad crack C to the widthwise edge Ge, one roller 15 of the pair of rollers 15, 15 described above is used. Note that Figs. 4(a) and (b) only show one roller 15 of the pair of rollers 15, 15 that is used to guide the bad crack C (the other roller 15 is not shown).

[0056] The one roller 15 is a roller 15 arranged above the one side region G1, which is the region having a smaller width dimension, of the one side region G1 and the other side region G2 of the glass ribbon G. In the guiding process P6, as shown in Figs. 4(a) and (b), the roller 15 is brought into contact with the one side region G1 to apply an external force F toward the downstream side of the conveying direction of the glass ribbon G to the one side region G1. At this time, the feed direction of the roller 15 is the same direction as the direction of the external force F to be applied, and further, the peripheral speed V1 of the roller 15 is set to be faster than the conveying speed V2 of the glass ribbon G. The position where the external force F is applied is between the width direction edge Ge and the defective crack C in the X direction. The position where the external force F is applied is sufficiently separated from the position where the unnecessary part cutting process P3 is performed in the Y direction. Therefore, the risk of the properties of the width direction edge Ge of the glass ribbon G being deteriorated due to the application of the external force F is eliminated.

[0057] When the roller 15 is brought into contact with the one-side region G1, the one-side region G1 is sandwiched in the thickness direction (Z direction) between the roller 15 and the board 13. In other words, during the guiding step P6, the board 13 functions as a support member that supports the roller 15 via the glass ribbon G (one-side region G1).

[0058] In the present embodiment, the external force F directed toward the downstream side of the conveying direction of the glass ribbon G is applied to the one-side region G1, but is not limited thereto. An external force F having a component directed toward the downstream side of the conveying direction of the glass ribbon G and a component directed from the center side toward the outside in the width direction may be applied to the one-side region G1. In other words, the direction of the external force F may be inclined with respect to the conveying direction of the glass ribbon G, and the magnitude of the inclination (angle θ shown in FIG. 4(a)) may be less than 90°. In this case, the feed direction of the roller 15 is set to the same direction as the direction of the external force F to be applied, and further, the component of the conveying direction of the glass ribbon G at the circumferential speed V1 of the roller 15 is set to be faster than the conveying speed V2 of the glass ribbon G.

[0059] When the external force F is applied to the one-side region G1 as described above, the conveying speed of the one-side region G1 is accelerated. This causes a tension difference between the one-side region G1 and the other-side region G2. Specifically, the tension T1 acting on the one-side region G1 becomes larger than the tension T2 acting on the other-side region G2. Due to this tension difference, the defective crack C advances (advances in the D2 direction) toward the edge Ge included in the one-side region G1 among both widthwise ends Ge, Ge of the glass ribbon G, and quickly reaches the edge Ge. When the defective crack C reaches the widthwise edge Ge, the advancement of the defective crack C toward the upstream side is stopped. Thereafter, the portion of the glass ribbon G upstream of the defective crack C is cut in the width direction. This separates the section in the longitudinal direction of the glass ribbon G where the defective crack C exists from the section where the defective crack C does not exist. Accordingly, the defective crack C is removed from the glass ribbon G, and the guiding process P6 is completed. After the completion of the guidance step P6, the execution of the interrupted acquisition step P5 is resumed.

[0060] Here, from the viewpoint of suitably applying the above-mentioned external force F, it is preferable to adopt, for example, butyl rubber, nitrile rubber, etc. as the material for the peripheral surface of the roller 15 (the surface in contact with the glass ribbon G). Furthermore, from the viewpoint of preventing the tension T1 acting on the glass ribbon G (one side region G1) from becoming excessive, it is preferable that the peripheral speed V1 of the roller 15 is within a range of 101% to 500% of the conveying speed V2 of the glass ribbon G as a reference.

[0061] It should be noted that the following modified examples can also be applied to the above embodiment.

[0062] In the above embodiment, when the defective crack C generated in the glass ribbon G is guided to the width direction edge Ge, a pair of rollers 15, 15 is arranged, and one of the rollers 15 is used. However, either one of the pair of rollers 15, 15 does not necessarily have to be present originally, and only a single roller 15 may be arranged. This single roller 15 may be arranged corresponding to either one side or the other side in the width direction of the glass ribbon G. Even if a single roller 15 is arranged corresponding to either one side or the other side, as long as a tension difference is provided between the tension T1 and the tension T2 (the magnitude relationship between T1 and T2 may be reversed), the defective crack C can be guided to the width direction edge Ge regardless of the generation position of the defective crack C (regardless of whether it is closer to one side or the other side in the width direction).

[0063] In the above embodiment, as an example of the occurrence of the defective crack C, a case where the defective crack C occurs from the cut end (the leading end of the glass ribbon G) when the glass ribbon G is cut in the width direction in the acquisition process P5 is given. Of course, the occurrence of the defective crack C is not limited to this, and the defective crack C may occur from the width direction edge Ge of the glass ribbon G after the unnecessary portion cutting process P3, or the defective crack C may occur in the glass ribbon G upstream of the unnecessary portion cutting process P3. In these cases, the guiding process P6 may be executed. Even in these cases, if the guiding process P6 is executed under the same arrangement of the imaging device 14 and the pair of rollers 15, 15 as in the above embodiment, the defective crack C occurring in the glass ribbon G can be guided to the width direction edge Ge.

[0064] In the above embodiment, the external force F is applied by bringing the roller 15 into contact with one side region G1 of the glass ribbon G. However, this is not limited thereto, and as shown in Fig. 5, the external force F may be applied by air A (gas) sprayed from a spray nozzle 16 toward the glass ribbon G on the board 13. The spray nozzle 16 is directed toward the downstream side in the conveying direction of the glass ribbon G from above the conveying path 11. Furthermore, instead of the air A sprayed from the roller 15 or the spray nozzle 16, the external force F may be applied manually by an operator.

[0065] In the above embodiment, the conveying speed of the one-side region G1 is accelerated to provide a tension difference between the one-side region G1 and the other-side region G2 of the glass ribbon G. However, this is not limited thereto, and the conveying speed of the one-side region G1 may be decelerated to provide a tension difference between the one-side region G1 and the other-side region G2.

[0066] In the above embodiment, the glass sheet Gs serving as the glass article is cut out from the glass ribbon G to produce the glass article. However, the glass ribbon G may be wound into a roll to produce a glass roll. [Explanation of symbols]

[0067] 1 Molded body 11 Transport Route 11e Downstream end 15 Roller A Air C Bad crack F external force G Glass ribbon G1 One side area G2 Other side part Ge Width direction edge Gs Glass plate Gx unnecessary part MG Molten Glass P1 Molding process P2 Conveyor direction change process P3 Unnecessary part cutting process P4 Transport process P5 acquisition process P6 Induction process T1,T2 tension V1 circumferential speed V2 conveying speed W1, W2 width dimensions

Claims

1. A method for manufacturing a glass article, comprising: a conveying step of conveying a glass ribbon along a conveying path; and an acquiring step of acquiring a glass article from the glass ribbon at a downstream end of the conveying path, When a defective crack that propagates toward an upstream side of the glass ribbon occurs in the glass ribbon, the defective crack is guided to a width direction edge of the glass ribbon, A method for manufacturing a glass article, characterized in that in the induction process, a tension difference is created between the tension generated in one side portion of the glass ribbon in the width direction and the tension generated in the other side portion separated by the defective crack.

2. The method for manufacturing a glass article according to claim 1 , characterized in that in the guiding step, the tension difference is provided by accelerating a transport speed of one of the one-side region and the other-side region.

3. The method for manufacturing a glass article as described in claim 2, characterized in that in the guiding process, the tension difference is created by applying to one of the one side portion and the other side portion (1) an external force directed downstream in the conveying direction of the glass ribbon, or (2) an external force having a component directed downstream in the conveying direction of the glass ribbon and a component directed from the center toward the outside in the width direction.

4. The method for manufacturing a glass article according to claim 3 , wherein the external force is applied to a portion of the glass ribbon located between a widthwise edge of the glass ribbon and the defective crack.

5. 5. The method for manufacturing a glass article according to claim 3, wherein the external force is applied to one of the one-side region and the other-side region, the one having a smaller width dimension.

6. The method for manufacturing a glass article according to claim 3 or 4, characterized in that, when applying the external force, a feed member having a feed direction that is the same as the direction of the external force is brought into contact with the glass ribbon.

7. The method for producing a glass article according to claim 6, wherein the feeding member is a roller.

8. The method for manufacturing a glass article according to claim 7, characterized in that the peripheral speed of the roller is set to be faster than the conveying speed of the glass ribbon when the roller is in contact with the glass ribbon.

9. 5. The method for manufacturing a glass article according to claim 3, wherein the external force is applied by spraying a gas toward the glass ribbon.

10. The method for manufacturing a glass article according to any one of claims 1 to 4, characterized in that in the guiding step, the glass ribbon is photographed to obtain an image, and the image is subjected to image processing to detect the occurrence of the defective crack.

11. The method for manufacturing a glass article according to any one of claims 1 to 4, characterized in that in the obtaining step, the glass ribbon is repeatedly cut in a width direction to continuously obtain a glass plate as the glass article.

12. The glass ribbon comprises: The thickness is 200 μm or less, The sheet is subjected to a forming step, a conveying direction changing step after the forming step, and an unnecessary part cutting step after the conveying direction changing step, and then to the conveying step; In the forming step, the glass ribbon is formed while being drawn out in a longitudinal direction from the molten glass supplied to a forming body, In the conveying direction changing process, the conveying direction of the glass ribbon after the forming process is changed from a vertical direction to a horizontal direction, The method for manufacturing a glass article according to any one of claims 1 to 4, characterized in that in the unnecessary portion cutting step, unnecessary portions present on one side and the other side in the width direction of the glass ribbon are cut and removed from the glass ribbon.

13. A method for manufacturing a glass article, comprising: a conveying step of conveying a glass ribbon along a conveying path; and an acquiring step of acquiring a glass article from the glass ribbon at a downstream end of the conveying path, When a defective crack that propagates toward an upstream side of the glass ribbon occurs in the glass ribbon, the defective crack is guided to a width direction edge of the glass ribbon, A method for manufacturing a glass article, characterized in that in the guiding step, an external force for guiding is applied to one of one side portion and the other side portion in the width direction of the glass ribbon separated by the defective crack as a boundary.

Images