Method and apparatus for manufacturing glass plate

Abstract

To maintain stable cutting of a glass ribbon over a long period of time.SOLUTION: A method for manufacturing a glass plate includes: a shaping step of shaping a glass ribbon Gr in a shaping furnace 2; an annealing step of annealing the glass ribbon Gr in an annealing furnace 3; a scribing step of forming a scribe line S on the glass ribbon Gr in a cutting chamber 5; a breaking step of obtaining a glass plate Gp of a predetermined size by breaking the glass ribbon Gr along the scribe line S in the cutting chamber 5; and a cooling step of blowing a cooling gas C1 onto the glass ribbon Gr in a cooling chamber 4 before the scribing step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and an apparatus for producing a glass sheet. [Background technology]

[0002] An example of a glass sheet manufacturing apparatus includes an apparatus including a forming furnace that forms a glass ribbon from molten glass by a down-draw method, an annealing furnace that communicates with the lower part of the forming furnace and anneals the glass ribbon, a cooling chamber that communicates with the lower part of the annealing furnace and cools the glass ribbon, and a cutting chamber that communicates with the lower part of the cooling chamber and cuts the glass ribbon at predetermined lengths to obtain glass sheets.

[0003] In the cutting chamber, a scribing device forms scribe lines on the glass ribbon, and then a breaking device breaks the glass ribbon along the scribe lines to obtain glass plates of a predetermined size (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 129907 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the flow rate of molten glass supplied to a forming furnace has been increasing in order to improve the production efficiency of glass sheets. Accordingly, the conveying speed of the glass ribbon is increasing downstream of the forming furnace, and the amount of heat brought by the glass ribbon to a cooling chamber or a cutting chamber per unit time is also increasing.

[0006] When the amount of heat brought in by the glass ribbon increases in this way, the glass ribbon cannot be sufficiently cooled in a conventional cooling chamber, and an insufficiently cooled glass ribbon is brought into the cutting chamber. Therefore, when forming a scribe line, the cutter of the scribing device comes into contact with the insufficiently cooled glass ribbon. However, the cutter of the scribing device is often made of a material with low heat resistance, such as a diamond tip. As a result, there is a problem that the cutter of the scribing device wears out due to heat and quickly loses its sharpness, making it impossible to properly form a scribe line on the glass ribbon. And when a scribe line is poorly formed in this way, poor cutting (failure to break) of the glass ribbon is likely to occur when the glass ribbon is bent and broken by the breaking device.

[0007] An object of the present invention is to cut a glass ribbon stably over a long period of time. [Means for solving the problem]

[0008] (1) The present invention, which has been invented to solve the above problems, is a method for manufacturing a glass sheet, comprising: a shaping step of forming a glass ribbon; an annealing step of annealing the glass ribbon in an annealing furnace; a scribing step of forming a scribe line in the glass ribbon; and a folding step of folding the glass ribbon along the scribe line to obtain a glass sheet of a predetermined size, and is characterized in that it comprises a cooling step of blowing a first cooling gas onto the glass ribbon before carrying out the scribing step.

[0009] In this way, in the scribing step, a scribe line can be formed on the glass ribbon that has been sufficiently cooled by blowing the first cooling gas, and therefore the cutter of the scribing device for forming the scribe line is less likely to be worn down by heat, making it possible to stably cut the glass ribbon for a long period of time.

[0010] (2) In the above configuration (1), the first cooling gas is preferably blown onto both sides of the glass ribbon.

[0011] In this way, the glass ribbon can be efficiently cooled by the first cooling gas.

[0012] (3) In the above configuration (1) or (2), the temperature of the first cooling gas is preferably 25° C. or less.

[0013] In this way, the glass ribbon can be efficiently cooled by the first cooling gas.

[0014] (4) In any of the configurations (1) to (3) above, it is preferable that the scribing step and the breaking step are performed in a cutting chamber, and the cooling step is performed in a cooling chamber that is provided upstream of the cutting chamber and downstream of the annealing furnace and communicates with the cutting chamber.

[0015] In this way, the cooling chamber in which the first cooling gas is blown onto the glass ribbon and the cutting chamber in which the glass ribbon is cut are separate chambers. Therefore, when the first cooling gas is blown onto the glass ribbon, foreign matter (particles) are less likely to adhere to the glass ribbon, and the glass ribbon can be kept in a clean state.

[0016] (5) In the above configuration (4), in the cooling step, it is preferable that the first cooling gas has a flow along the glass ribbon from the cooling chamber to the cutting chamber.

[0017] In this way, the direction in which the glass ribbon is transported and the direction in which the first cooling gas flows are the same, so that the time during which the glass ribbon is in contact with the first cooling gas can be extended, and the glass ribbon can be efficiently cooled.

[0018] (6) In the above configuration (5), the first cooling gas is preferably blown onto the glass ribbon at a position in the cooling chamber closer to the cutting chamber.

[0019] In this way, the first cooling gas is sprayed in the vicinity of the cutting chamber, making it easier to generate an airflow heading from the cooling chamber toward the cutting chamber.

[0020] (7) In the above configuration (5) or (6), in the cooling step, a first cooling gas that has been sucked from within the cutting chamber and cooled may be blown onto the glass ribbon in the cooling chamber.

[0021] This makes it easier to generate an air current flowing from the cooling chamber to the cutting chamber.

[0022] (8) In any of the above configurations (1) to (7), the first cooling gas is preferably blown onto the glass ribbon after passing through a filter.

[0023] In this way, foreign matter is less likely to adhere to the glass ribbon when the first cooling gas is blown thereon.

[0024] (9) In any of the above configurations (4) to (8), it is preferable that the second cooling gas is supplied into the cutting chamber through an air supply port provided in the cutting chamber.

[0025] In this way, the room temperature in the cutting chamber can be lowered by the second cooling gas, so that the glass ribbon can be cooled more effectively in the cutting chamber, and as a result, wear of the cutter of the scribing device due to heat is less likely to occur.

[0026] (10) In the above configuration (9), the second cooling gas that has been sucked in from within the cutting chamber and cooled may be supplied into the cutting chamber.

[0027] In this way, the temperature in the cutting chamber can be efficiently adjusted.

[0028] (11) In the above configuration (9) or (10), the second cooling gas is preferably supplied into the cutting chamber after passing through a filter.

[0029] In this way, the cleanliness of the gas in the cutting chamber can be improved, and adhesion of foreign matter to the glass ribbon and the glass sheet can be reduced.

[0030] (12) In any of the above configurations (1) to (11), the glass ribbon preferably has a sheet thickness of 0.3 mm or more and 0.7 mm or less.

[0031] In this way, a glass plate can be obtained that can be suitably used as a cover glass or a substrate for various electronic terminals and display devices.

[0032] (13) The present invention, which has been invented to solve the above problems, is a glass sheet manufacturing apparatus including a forming furnace for forming a glass ribbon, an annealing furnace for annealing the glass ribbon, a scribing device for forming a scribe line in the glass ribbon, and a bending and breaking device for bending and breaking the glass ribbon along the scribe line to obtain a glass sheet of a predetermined size, characterized in that it includes a cooling device that blows a first cooling gas onto the glass ribbon before the scribe line is formed by the scribing device.

[0033] In this way, the same effects as those of the corresponding configuration described above can be obtained. Effect of the Invention

[0034] According to the present invention, it is possible to stably cut a glass ribbon over a long period of time. [Brief description of the drawings]

[0035] [Figure 1] 1 is a vertical sectional side view showing a glass sheet manufacturing apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a vertical sectional front view showing a glass sheet manufacturing apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a cross-sectional view of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, XYZ is a Cartesian coordinate system. The X and Y directions are horizontal directions, and the Z direction is vertical. Among the horizontal directions, the X direction may be called the width direction.

[0037] (Glass plate manufacturing equipment) As shown in FIG. 1 and FIG. 2, the glass sheet manufacturing apparatus 1 according to the present embodiment includes a forming furnace 2, an annealing furnace 3 located below the forming furnace 2, a cooling chamber 4 located below the annealing furnace 3, and a cutting chamber 5 located below the cooling chamber 4. The forming furnace 2 and the annealing furnace 3, the annealing furnace 3 and the cooling chamber 4, and the cooling chamber 4 and the cutting chamber 5 are separated by partition members (e.g., floors of buildings) 6, 7, and 8 having openings (e.g., slits) 6a, 7a, and 8a through which the glass ribbon Gr passes, respectively. The glass ribbon Gr is transported in the order of the forming furnace 2, the annealing furnace 3, the cooling chamber 4, and the cutting chamber 5, so that the upper side where the forming furnace 2 is arranged is the upstream side, and the lower side where the cutting chamber 5 is arranged is the downstream side. That is, the glass ribbon Gr is transported from the upper side to the lower side of the glass sheet manufacturing apparatus 1.

[0038] The forming furnace 2 is a region for forming the glass ribbon Gr from the molten glass Gm by the overflow downdraw method. Inside the forming furnace 2, a forming body 9 for forming the glass ribbon Gr from the molten glass Gm and edge rollers 10 for cooling both ends in the width direction of the glass ribbon Gr formed by the forming body 9 are arranged.

[0039] A groove (overflow groove) 9a is formed in the width direction at the top of the forming body 9. One end of the groove 9a is connected to a supply pipe 11. Molten glass Gm is supplied into the groove 9a through the supply pipe 11.

[0040] Both outer sides of the molded body 9 each include a vertical surface portion 9b along the vertical direction and an inclined surface portion 9c that is connected to the lower side of the vertical surface portion 9b and inclined with respect to the vertical direction. The vertical surface portions 9b are planes parallel to each other. The inclined surface portions 9c are planes that are inclined so as to approach each other as they go downward. In other words, the molded body 9 has a wedge shape that tapers downward when viewed from the side due to the formation of the inclined surface portions 9c, and the corner where the inclined surface portions 9c intersect forms the lower end portion 9d of the molded body 9.

[0041] The edge rollers 10 are configured as a pair of rollers that pinch each end of the glass ribbon Gr in the width direction below the forming body 9. The edge rollers 10 are constantly cooled internally during the forming process. Therefore, the edge rollers 10 are sometimes referred to as cooling rollers.

[0042] The annealing furnace 3 is a region for reducing warpage and distortion of the glass ribbon Gr. An annealing roller 12 is arranged inside the annealing furnace 3. The annealing roller 12 is configured as a pair of rollers that hold both ends of the glass ribbon Gr in the width direction. The annealing rollers 12 are provided in a plurality of stages on a transport path of the glass ribbon Gr along the vertical direction.

[0043] The cooling chamber 4 is a region for cooling the glass ribbon Gr to near room temperature. Inside the cooling chamber 4, transport rollers 13 are arranged. The transport rollers 13 are configured as a pair of rollers that hold both ends of the glass ribbon Gr in the width direction. The transport rollers 13 are provided in a plurality of stages in the vertical direction.

[0044] The cutting chamber 5 is a region for cutting the glass ribbon Gr into pieces of a predetermined length in the width direction to obtain a glass sheet Gp. In this embodiment, the cutting chamber 5 includes a first cutting chamber 5a and a second cutting chamber 5b located below the first cutting chamber 5a. The first cutting chamber 5a and the second cutting chamber 5b are separated by a partition member (e.g., a floor surface of a building) 14 having an opening (e.g., a slit) 14a through which the glass ribbon Gr can pass.

[0045] A first cutting device 15 is disposed inside the first cutting chamber 5a. The first cutting device 15 includes a scribing device 16 and a cutting device 17.

[0046] The scribing device 16 is a device that forms a scribe line S on the first main surface Ga of the glass ribbon Gr descending from the cooling chamber 4 at a scribe line forming position P1. In this embodiment, the scribing device 16 includes a cutter (e.g., a wheel cutter) 18 that forms a scribe line S along the width direction on the first main surface Ga of the glass ribbon Gr, and a support member 19 (e.g., a support bar or a support roller) that supports the second main surface Gb of the glass ribbon Gr at a position corresponding to the cutter 18. The cutter 18 and the support member 19 are configured to form the scribe line S on the entire area or part of the width direction of the first main surface Ga of the glass ribbon Gr while moving following the glass ribbon Gr that moves continuously downward. Specifically, for example, the cutter 18 moves obliquely downward while contacting the first main surface Ga of the descending glass ribbon Gr in order to form a linear scribe line S along the width direction of the glass ribbon Gr.

[0047] The breaking device 17 is a device that breaks the glass ribbon Gr along the scribe line S at a breaking position P2 provided below the scribe line forming position P1 to cut out a glass sheet Gp. In this embodiment, the breaking device 17 includes a breaking member 20 that contacts the region where the scribe line S is formed from the second main surface Gb side, and a gripping mechanism 21 that grips the lower region of the glass ribbon Gr below the breaking position P2. The breaking member 20 is composed of a plate-like body having a contact surface that contacts the entire region or a part of the second main surface Gb of the glass ribbon Gr in the width direction. The gripping mechanism 21 includes chucks 22 provided at multiple positions in the up and down directions at both ends in the width direction of the glass ribbon Gr, and arms 23 that hold the multiple chucks 22 at both ends in the width direction.

[0048] The breaking member 20 and the gripping mechanism 21 perform the following operations. First, the multiple chucks 22 grip the glass ribbon Gr, and then the arm 23 moves the multiple chucks 22 following the descent of the glass ribbon Gr. At this time, the breaking member 20 also moves following the downward movement of the glass ribbon Gr. While these movements are being performed, the arm 23 performs an operation for bending the glass ribbon Gr with the breaking member 20 as a fulcrum. This applies bending stress to the scribe line S and its vicinity, and the glass ribbon Gr is broken in the width direction along the scribe line S. As a result of cutting by this bending, a glass plate Gp is ​​cut out from the glass ribbon Gr.

[0049] A second cutting device 24 is disposed inside the second cutting chamber 5b. The second cutting device 24 is a device for cutting and recovering the glass ribbon Gr that continues to be formed when the first cutting device 15 cannot be used due to maintenance or the like. A recovery chamber 25 for recovering the glass cut by the second cutting device 24 is provided below the second cutting chamber 5b. The second cutting chamber 5b and the recovery chamber 25 are separated by a partition member (e.g., a floor surface of a building) 26 having an opening (e.g., a slit) 26a for dropping the cut glass into the recovery chamber 25.

[0050] Here, if the cooling of the glass ribbon Gr is insufficient, the cutter 18 of the scribing device 16 will wear out early. As a result, the scribe line S cannot be properly formed, and the cutting of the glass ribbon Gr cannot be stably continued. Therefore, the manufacturing apparatus 1 further includes a cooling device 27 in order to sufficiently cool the glass ribbon Gr. In the present embodiment, the cooling device 27 includes a first cooling device 28 and a second cooling device 29.

[0051] The first cooling device 28 includes a main body 30, a pipe 31, air inlets 32, 33, and 34, and a filter 35.

[0052] In this embodiment, the main body 30 is disposed in the second cutting chamber 5b. The main body 30 is, for example, an air conditioner, and is configured to form the cooling gas C1 by sucking in and cooling the gas A1 in the second cutting chamber 5b. In other words, the cooling gas C1 is air. The temperature of the cooling gas C1 is preferably, for example, 12°C or higher and 25°C or lower. The upper limit of the temperature of the cooling gas C1 is more preferably 23°C or lower, and even more preferably 20°C or lower.

[0053] The piping 31 is for circulating the cooling gas C1 formed in the main body 30 inside, and extends from the second cutting chamber 5b through the first cutting chamber 5a to the cooling chamber 4. In the present embodiment, a tip portion of the piping 31 is branched in the first cutting chamber 5a into a first branch piping 31a extending to the first main surface Ga side of the glass ribbon Gr and a second branch piping 31b extending to the second main surface Gb side.

[0054] The air supply ports 32, 33, and 34 are provided in the pipe 31 and serve to supply the cooling gas C1 circulating inside the pipe 31 to the outside.

[0055] The air supply port 32 provided in the middle of the piping 31 is located in the first cutting chamber 5a. The air supply port 32 is arranged to supply a cooling gas (corresponding to a second cooling gas) C1 into the first cutting chamber 5a at a position away from the glass ribbon Gr in the first cutting chamber 5a. That is, the cooling gas C1 supplied from the air supply port 32 is not directly blown onto the glass ribbon Gr in the first cutting chamber 5a, but is mainly used to adjust the temperature in the first cutting chamber 5a. The position of the air supply port 32 is not particularly limited as long as it is in the first cutting chamber 5a. For example, the air supply port 32 may be provided at a middle position in the height direction of the first cutting chamber 5a, but in this embodiment, it is provided on the ceiling of the first cutting chamber 5a. The number of the air supply port 32 may be more than one, but in this embodiment, it is one.

[0056] The air supply ports 33, 34 provided at the tip of the pipe 31 are located inside the cooling chamber 4. The air supply ports 33, 34 are configured to blow a cooling gas (corresponding to a first cooling gas) C1 onto the glass ribbon Gr in the cooling chamber 4.

[0057] In detail, the cooling gas C1 supplied from the air supply port 33 provided in the first branch pipe 31a is blown onto the first main surface Ga of the glass ribbon Gr on which the scribe line S is formed. On the other hand, the cooling gas C1 supplied from the air supply port 34 provided in the second branch pipe 31b is blown onto the second main surface Gb of the glass ribbon Gr on which the scribe line S is not formed. The lower limit of the surface temperature of the glass ribbon Gr when the cooling gas C1 is blown onto the glass ribbon Gr is preferably 100°C or more, more preferably 120°C or more, and further preferably 140°C or more. The upper limit of the surface temperature of the glass ribbon Gr when the cooling gas C1 is blown onto the glass ribbon Gr is preferably 240°C or less, more preferably 220°C or less, and further preferably 200°C or less. In this embodiment, as shown in FIG. 3, the air supply ports 33 and 34 are each provided in a plurality (three in the illustrated example) in the width direction of the glass ribbon Gr, so that the entire width direction of both main surfaces Ga and Gb of the glass ribbon Gr is cooled by the cooling gas C1. In addition, at both ends in the width direction of the glass ribbon Gr, there are cases where ears Gy having a greater sheet thickness than the width direction central portion Gx are formed. The ears Gy are difficult to cool because they have a greater sheet thickness than the width direction central portion Gx of the glass ribbon Gr. Therefore, when the cutter 18 of the scribing device 16 is used to form a scribe line S over the entire width direction of the glass ribbon Gr, it is preferable to directly blow the cooling gas C1 onto the portion including the ears Gy. On the other hand, when the cutter 18 of the scribing device 16 is used to form a scribe line S only in the width direction central portion Gx of the glass ribbon Gr, it is preferable to directly blow the cooling gas C1 onto only the width direction central portion Gx.

[0058] The positions of the air supply ports 33, 34 are not particularly limited as long as they are within the cooling chamber 4, but in this embodiment, they are located at the lower part of the cooling chamber 4 (near the opening 8a). By supplying the cooling gas C1 at the lower part of the cooling chamber 4 in this manner, an air flow F1 directed from the cooling chamber 4 toward the first cutting chamber 5a is easily formed, so that foreign matter such as glass powder generated in the first cutting chamber 5a is less likely to enter the cooling chamber 4.

[0059] The height position of the air supply port 33 may be different from the height position of the air supply port 34, but is preferably the same as the height position of the air supply port 34. If the air supply ports 33, 34 are at the same height positions, both main surfaces Ga, Gb of the glass ribbon Gr are pressed simultaneously at the same height positions by the cooling gas C1. Therefore, even if the flow rate (air volume) of the cooling gas C1 to be blown is increased, it is possible to prevent the glass ribbon Gr from unduly warping or shaking.

[0060] Either one of the air inlets 33, 34 may be omitted. When only one of the air inlets 33, 34 is provided, it is preferable to provide the air inlet 33 that blows the cooling gas C1 onto the first main surface Ga of the glass ribbon Gr on which the scribe line S is to be formed. However, from the viewpoint of efficiently cooling the portion of the glass ribbon Gr on which the scribe line S is to be formed, it is preferable to provide both air inlets 33, 34 and blow the cooling gas C1 onto both main surfaces Ga, Gb of the glass ribbon Gr.

[0061] The filter 35 is provided on the flow path of the piping 31 from the main body 30 to the air inlet 32 ​​(the air inlet located closest to the main body 30), and removes foreign matter contained in the cooling gas C1 flowing through the piping 31. This allows the air inlets 32, 33, and 34 to supply the cooling gas C1 with high cleanliness that has passed through the filter 35. That is, even if the cleanliness of the gas A1 sucked by the main body 30 in the second cutting chamber 5b is low, the filter 35 can provide the cooling gas C1 with high cleanliness. Therefore, adhesion of foreign matter to the glass ribbon Gr and the glass sheet Gp can be suppressed. The filter 35 is composed of a high-performance filter such as a HEPA filter or a ULPA filter. In this embodiment, the filter 35 is provided in the piping 31 at a position away from the air inlet 32 ​​to the main body 30 (in the illustrated example, near the floor surface of the first cutting chamber 5a), but may be provided immediately before the air inlet 32. Alternatively, the filters may be provided immediately before each of the air intakes 32, 33, and 34 individually.

[0062] The second cooling device 29 includes a main body 36, a pipe 37, an air supply port 38, and a filter 39. Unlike the first cooling device 28, the second cooling device 29 does not directly supply the cooling gas C2 into the cooling chamber 4.

[0063] In this embodiment, the main body 36 is disposed in the second cutting chamber 5b. The main body 36 is, for example, an air conditioner, and is configured to form the cooling gas C2 by sucking in and cooling the gas A2 in the second cutting chamber 5b. That is, the cooling gas C2 is air. The temperature of the cooling gas C2 is preferably, for example, 12°C or higher and 25°C or lower. The upper limit of the temperature of the cooling gas C2 is more preferably 23°C or lower, and further preferably 20°C or lower. The temperature of the cooling gas C1 supplied by the first cooling device 28 and the temperature of the cooling gas C2 supplied by the second cooling device 29 may be the same or different.

[0064] The flow rate of the cooling gas C1 supplied from the air inlet 32 ​​to the first cutting chamber 5a and the flow rate of the cooling gas C2 supplied from the air inlet 38 to the first cutting chamber 5a are, for example, 4000 m 3 / hour more than 25000m 3 / hour or less. The flow rates of the cooling gas C1 supplied from the air inlet 32 ​​to the first cutting chamber 5a and the cooling gas C2 supplied from the air inlet 38 to the first cutting chamber 5a may be the same or different.

[0065] The piping 37 is for circulating the cooling gas C2 formed in the main body portion 36 inside, and extends from the second cutting chamber 5b to the first cutting chamber 5a.

[0066] The air supply port 38 is provided in the piping 37, and is for supplying the cooling gas C2 circulated in the piping 37 to the outside. The air supply port 38 is provided in the first cutting chamber 5a. The air supply port 38 is configured to supply the cooling gas (corresponding to the second cooling gas) C2 into the first cutting chamber 5a at a position away from the glass ribbon Gr in the first cutting chamber 5a. The position of the air supply port 38 is not particularly limited as long as it is in the first cutting chamber 5a. For example, the air supply port 38 may be provided at a middle position in the height direction of the first cutting chamber 5a, but in this embodiment, it is provided on the ceiling of the first cutting chamber 5a. The number of the air supply ports 38 may be one, but is multiple (two in the illustrated example) in this embodiment.

[0067] The filter 39 is provided on the flow path of the piping 37 from the main body 36 to the air inlet 38 (the air inlet located closest to the main body 30) and removes foreign matter contained in the cooling gas C2 flowing through the piping 37. The filter 39 is composed of a high-performance filter such as a HEPA filter or a ULPA filter. In this embodiment, the filter 39 is provided on the piping 37 at a position away from the air inlet 38 to the main body 36 side (in the illustrated example, near the floor surface of the first cutting chamber 5a), but may be provided just before the air inlet 38.

[0068] (Glass plate manufacturing method) The method for manufacturing a glass sheet according to this embodiment is carried out using the manufacturing apparatus 1 having the above-mentioned configuration. This manufacturing method includes a forming step, an annealing step, a cooling step, and a cutting step.

[0069] In the forming process, in the forming furnace 2, the molten glass Gm is supplied to the groove 9a of the forming body 9, and the molten glass Gm overflowing from the groove 9a on both sides flows down along the vertical surface 9b and the inclined surface 9c and joins again at the lower end 9d. In this way, the glass ribbon Gr is continuously formed from the molten glass Gm. The thickness of the glass ribbon Gr is preferably 0.3 mm or more and 0.7 mm or less. A glass sheet Gp cut out from such a glass ribbon Gr can be suitably used as a cover glass or a substrate for various electronic terminals and display devices.

[0070] In the annealing step, the glass ribbon Gr is annealed in the annealing furnace 3 while being conveyed downward by annealer rollers 12.

[0071] In the cooling step, in the cooling chamber 4, the glass ribbon Gr is transported downward by the transport rollers 13 and cooled to approximately room temperature.

[0072] In the cutting step, in the first cutting chamber 5a, the glass ribbon Gr is cut in the width direction at predetermined lengths by the first cutting device 15 to obtain a glass sheet Gp. In detail, the cutting step includes a scribing step of forming a scribe line S in the glass ribbon Gr by the scribing device 16, and a folding step of folding the glass ribbon Gr along the scribe line S to obtain a glass sheet Gp by the folding device 17. Note that the cutting step may further include a step of removing ears (corresponding to the ears Gy of the glass ribbon Gr) at both ends in the width direction of the glass sheet Gp by a cutting device not shown after cutting out the glass sheet Gp from the glass ribbon Gr.

[0073] Here, in the cooling step, in order to sufficiently cool the glass ribbon Gr, before the scribing step is performed, a cooling gas C1 is blown onto both main surfaces Ga, Gb of the glass ribbon Gr in the cooling chamber 4 from the air inlets 33, 34 of the first cooling device 28. As a result, the glass ribbon Gr reaching the scribe line forming position P1 in the first cutting chamber 5a is in a sufficiently cooled state. Therefore, even if the cutter 18 is brought into contact with the first main surface Ga of the glass ribbon Gr at the scribe line forming position P1 to form the scribe line S, the cutter 18 is unlikely to be worn down by heat. As a result, the scribe line S can be appropriately formed, and the glass ribbon Gr can be stably cut for a long period of time.

[0074] In addition, by blowing the cooling gas C1 to the glass ribbon Gr in the cooling chamber 4, at least a part of the cooling gas C1 becomes the air flow F1 moving from the cooling chamber 4 to the first cutting chamber 5a along the glass ribbon Gr. As a result, the direction in which the glass ribbon Gr is transported and the direction in which the cooling gas C1 (air flow F1) are transported become the same direction, and the time in which the glass ribbon Gr and the cooling gas C1 are in contact with each other becomes longer, so that the glass ribbon Gr can be efficiently cooled. In addition, this air flow F1 can suppress the intrusion of foreign matter such as glass powder generated in the first cutting chamber 5a into the cooling chamber 4. Here, the air flow F1 is more likely to be generated by blowing the cooling gas C1 to the glass ribbon Gr at the lower part in the cooling chamber 4. This is because the cooling gas C1 pressurizes the vicinity of the opening 8a in the cooling chamber 4, making it easier for gas to flow from the cooling chamber 4 to the first cutting chamber 5a. Moreover, the airflow F1 is more easily generated by sucking in the gas A1 in the first cutting chamber 5a and / or the second cutting chamber 5b (in this embodiment, the second cutting chamber 5b) and supplying the cooled gas C1 into the cooling chamber 4. This is because the cooling chamber 4 is pressurized and the first cutting chamber 5a and / or the second cutting chamber 5b are depressurized.

[0075] In the cooling process, the cooling gases C1 and C2 are also supplied into the first cutting chamber 5a from the air supply ports 32 and 38 provided in the first cutting chamber 5a. In this way, the room temperature of the first cutting chamber 5a can be lowered by the cooling gases C1 and C2. Therefore, the cooling effect of the glass ribbon Gr can be improved. In addition, if the room temperature of the first cutting chamber 5a becomes too high, the grease of various devices arranged in the first cutting chamber 5a may liquefy and contaminate the glass ribbon Gr and the glass sheet Gp, but this can be prevented. As a result, the glass ribbon Gr and the glass sheet Gp can be easily kept in a clean state. The room temperature of the first cutting chamber 5a is preferably 18°C ​​or higher and 25°C or lower. If the temperature is within such a range, there is also an advantage that the operator can easily work in the first cutting chamber 5a.

[0076] In this embodiment, the cooling gases C1 and C2 sucked and cooled from the second cutting chamber 5b are supplied into the first cutting chamber 5a by the first cooling device 28 and the second cooling device 29. This makes it easier to adjust the room temperature in the first cutting chamber 5a. In addition, since the first cutting chamber 5a is pressurized and the second cutting chamber 5b is depressurized, it is easier to form the airflow F2 from the first cutting chamber 5a to the second cutting chamber 5b.

[0077] In order to form an airflow F1 from the cooling chamber 4 to the first cutting chamber 5a, an airflow F2 from the first cutting chamber 5a to the second cutting chamber 5b, and an airflow F3 from the second cutting chamber 5b to the recovery chamber 25, it is preferable to adjust the air pressure in each chamber 4, 5a, 5b, 25 so that the air pressure decreases in the order of the cooling chamber 4, the first cutting chamber 5a, and the second cutting chamber 5b.

[0078] In the cooling step, the cooling gas C1 that has passed through the filter 35 is supplied into the cooling chamber 4, so that the glass ribbon Gr can be kept clean. In addition, the cooling gases C1 and C2 that have passed through the filters 35 and 39 are supplied into the first cutting chamber 5a, so that the cleanliness of the gas in the first cutting chamber 5a can be improved.

[0079] Although an embodiment of the present invention has been described, the embodiment of the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention.

[0080] In the above embodiment, the case where the cooling gas C1 is blown over the entire width of the glass ribbon Gr is described. However, the cooling gas C1 may be blown over only a portion of the width of the glass ribbon Gr, for example, only the width central portion Gx of the glass ribbon Gr.

[0081] In the above embodiment, when the cooling gas C1 is blown onto the glass ribbon Gr from a plurality of air supply ports, the temperature and / or flow rate of the cooling gas C1 supplied from one cooling port may be different from the temperature and / or flow rate of the cooling gas C1 supplied from the other cooling ports. For example, the temperature and / or flow rate of the cooling gas C1 supplied from each air supply port may be adjusted so that the edge portions Gy of the glass ribbon Gr are cooled more strongly than the width direction central portion Gx of the glass ribbon Gr. Alternatively, the temperature and / or flow rate of the cooling gas C1 supplied from each air supply port may be adjusted so that the first main surface Ga side of the glass ribbon Gr is cooled more strongly than the second main surface Gb side of the glass ribbon Gr.

[0082] In the above embodiment, the cooling gas C1 is blown onto the glass ribbon Gr in the cooling chamber 4, but this is not limited thereto. The blowing position of the cooling gas C1 may be, for example, in the first cutting chamber 5a, so long as it is the scribe line forming position P1 (strictly speaking, the position where the cutter 18 first comes into contact with the glass ribbon Gr) or above (upstream) it.

[0083] In the above embodiment, the case has been described in which the cooling gas C1 is continuously blown at a predetermined position against the continuously descending glass ribbon Gr to cool a wide range including the portion where the scribe line S is to be formed, but the present invention is not limited to this. For example, the cooling gas C1 may be intermittently blown at a predetermined position against the continuously descending glass ribbon Gr to cool only the portion where the scribe line S is to be formed or a narrow range including the portion where the scribe line S is to be formed (for example, a linear region extending in the width direction including the portion where the scribe line S is to be formed).

[0084] In the above embodiment, the cooling gases C1 and C2 are air, but the cooling gases C1 and C2 may be, for example, oxygen, nitrogen, dry air, or the like.

[0085] In the above embodiment, the location of the main body parts 30, 36 of the cooling devices 28, 29 is not particularly limited. For example, the main body parts 30, 36 may be disposed in the first cutting chamber 5a. In this case, the main body parts 30, 36 form the cooling gases C1, C2 by sucking in and cooling the gas in the first cutting chamber 5a.

[0086] In the above embodiment, the case where the cutting chamber 5 is separated into two, the first cutting chamber 5a and the second cutting chamber 5b, has been described, but the second cutting chamber 5b may be omitted.

[0087] In the above embodiment, the case where the glass ribbon Gr is formed by using the overflow downdraw method has been described, but the method for forming the glass ribbon Gr is not particularly limited. For example, as the method for forming the glass ribbon Gr, other downdraw methods such as a slot downdraw method or a redraw method, or a float method may be used.

[0088] In the above embodiment, the first cooling device 28 blows the cooling gas C1 onto the glass ribbon in the cooling chamber 4 to generate the airflow F1 from the cooling chamber 4 to the first cutting chamber 5a, but this is not limited thereto. In addition to the first cooling device 28, a gas supply device that supplies gas into the cooling chamber 4 may be provided. The gas supply device may supply gas from a location other than the second cutting chamber 5b in the glass sheet manufacturing apparatus 1, or may supply gas from outside the glass sheet manufacturing apparatus 1. In addition, the gas supplied to the cooling chamber 4 by the gas supply device may or may not be cooled by the gas supply device. [Explanation of symbols]

[0089] 1 Manufacturing equipment 2 Molding furnace 3 Annealing furnace 4 Cooling room 5 Cutting chamber 5a First cutting room 5b Second cutting room 9 Molded body 15 First cutting device 16 Scribing device 17 Folding device 24 Second cutting device 25 Recovery Room 27 Cooling device 28 First cooling device 29 Second cooling device 30 Main body 31 Piping 32 Air supply port 33 Air supply port 34 Air supply port 35 Filters 36 Main body 37 Piping 38 Air supply port 39 Filters C1 Cooling gas C2 Cooling Gas Gp Glass Plate Gr Glass ribbon P1 scribe line formation position P2 folding position S scribe line

Claims

1. A method for manufacturing a glass sheet, comprising: a forming step of forming a glass ribbon; an annealing step of annealing the glass ribbon in an annealing furnace; a scribing step of forming a scribe line in the glass ribbon; and a folding step of folding the glass ribbon along the scribe line to obtain a glass sheet of a predetermined size, A method for manufacturing a glass sheet, comprising the steps of: blowing a first cooling gas onto the glass ribbon before the scribing step is performed.

2. The method for producing a glass sheet according to claim 1 , wherein the first cooling gas is blown onto both sides of the glass ribbon.

3. The method for producing a glass sheet according to claim 1 or 2, wherein the first cooling gas has a temperature of 25° C. or lower.

4. 3. The method for manufacturing a glass sheet according to claim 1, wherein the scribing step and the bending step are performed in a cutting chamber, and the cooling step is performed in a cooling chamber that is provided upstream of the cutting chamber and downstream of the annealing furnace and communicates with the cutting chamber.

5. The method for producing a glass sheet according to claim 4 , wherein in the cooling step, the first cooling gas has a flow along the glass ribbon from the cooling chamber to the cutting chamber.

6. The method for manufacturing a glass sheet according to claim 5 , wherein the first cooling gas is blown onto the glass ribbon at a position in the cooling chamber closer to the cutting chamber.

7. The method for manufacturing a glass sheet according to claim 5 , wherein in the cooling step, the first cooling gas that has been sucked from the cutting chamber and cooled is blown onto the glass ribbon in the cooling chamber.

8. The method for producing a glass sheet according to claim 7 , wherein the first cooling gas is blown onto the glass ribbon after passing through a filter.

9. The method for manufacturing a glass sheet according to claim 4, wherein a second cooling gas is supplied into the cutting chamber through an air supply port provided in the cutting chamber.

10. The method for manufacturing a glass sheet according to claim 9, wherein the second cooling gas that has been sucked from within the cutting chamber and cooled is supplied into the cutting chamber.

11. The method for producing a glass sheet according to claim 10, wherein the second cooling gas is supplied into the cutting chamber after passing through a filter.

12. The method for producing a glass sheet according to claim 1 or 2, wherein the glass ribbon has a thickness of 0.3 mm or more and 0.7 mm or less.

13. A glass sheet manufacturing apparatus including: a forming furnace that forms a glass ribbon; an annealing furnace that anneals the glass ribbon; a scribing device that forms a scribe line in the glass ribbon; and a breaking device that breaks the glass ribbon along the scribe line to obtain a glass sheet of a predetermined size, An apparatus for manufacturing a glass sheet, comprising: a cooling device that blows a first cooling gas onto the glass ribbon before the scribe line is formed by the scribing device.

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