Glass plate manufacturing method and manufacturing device

Abstract

To properly deal with poor cutting, impossible cutting or the like to prevent a longitudinal crack or the like when conducting a second cutting step instead of a first cutting step to a glass ribbon continuously moving downward while formed.SOLUTION: A manufacturing method of a glass plate includes a first cutting step for taking a glass plate out by cutting a glass ribbon G along the width direction, the glass ribbon G continuously moving downward while formed in a forming zone 11 and a second cutting step for cutting the glass ribbon G using a device 3 of different composition from a device 2 used in the first cutting step when the first cutting step is not conducted. In the second cutting step, the state of cutting of the glass ribbon G is checked by a sensor 35 and the glass ribbon G is cut based on the result checked by the sensor 35.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a technology for manufacturing glass sheets, and more particularly to a technology for performing a first cut to cut a glass sheet by cutting a glass ribbon that is continuously moving downward while being formed, and a second cut to cut the glass ribbon when the first cut is not performed. [Background technology]

[0002] In the field of glass sheet manufacturing, it is known to perform a first cutting step in which a glass ribbon that is being formed in a forming zone and moving downward continuously is cut in the width direction at predetermined lengths to sequentially cut out glass sheets. In this case, since the melting furnace or the like of the glass sheet manufacturing facility is usually operated continuously, even if the device for performing the first cutting step cannot be used during maintenance or the like, the glass ribbon generally continues to be formed. Therefore, even if the first cutting step is not performed, it is necessary to cut and recover the glass ribbon that continues to be formed.

[0003] In order to meet such a demand, for example, Patent Document 1 discloses that when the first cutting step is not performed, a second cutting step is performed in which the glass ribbon is cut using an apparatus having a configuration different from that of the apparatus used in the first cutting step. The apparatus used in this second cutting step includes a holding member for holding the glass ribbon, a pressing member for applying stress to the glass ribbon while the glass ribbon is held by the holding member, and a scribing member for scribing a scribing line in the portion of the glass ribbon to which stress is applied. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] China Utility Model Publication No. 205493369 Summary of the Invention [Problem to be solved by the invention]

[0005] The device used in the second cutting step in Patent Document 1 has a simpler configuration than the device used in the first cutting step (see paragraph

[0005] in the same document, etc.). However, when this device is used, cutting defects or inability to cut easily occur.

[0006] For example, in the process of the glass ribbon continuously moving downward, the lower end of the glass ribbon may get caught on a component (e.g., a pressing member) of the above-mentioned device or may collide with a dead end of the moving path of the glass ribbon, resulting in defects such as a crack progressing along the vertical direction of the glass ribbon to cause vertical cracks.

[0007] From the above viewpoints, the present invention aims to prevent the occurrence of vertical cracks, etc., by being able to appropriately respond to cutting defects or inability to cut when a second cutting process is performed instead of a first cutting process on a glass ribbon that is being formed and moving continuously downward. [Means for solving the problem]

[0008] A first aspect of the present invention, which has been devised to solve the above-mentioned problems, is a glass sheet manufacturing method comprising: a first cutting step of cutting a glass ribbon, which is being formed in a forming zone and moving continuously downward, along the width direction to cut out a glass sheet; and a second cutting step of cutting the glass ribbon using an apparatus having a configuration different from that of the apparatus used in the first cutting step when the first cutting step is not performed, wherein the second cutting step is characterized in that a state of the glass ribbon is inspected by a sensor, and a cutting process of the glass ribbon is performed based on the inspection result of the sensor.

[0009] According to this configuration, when the second cutting step is performed instead of the first cutting step, the state of the glass ribbon is inspected by the sensor, so that it is possible to take appropriate measures against occurrence of poor cutting, inability to cut, etc. In detail, for example, if poor cutting, inability to cut, etc. occurs during the preceding cutting process, the sensor quickly and accurately detects this, and the detection result is reflected in the cutting process. Therefore, in the cutting process, appropriate cutting can be performed so that the lower end of the glass ribbon does not get in the way. As a result, it is possible to prevent occurrence of vertical cracks in the glass ribbon in advance.

[0010] In this configuration, the sensor may inspect whether or not the glass ribbon has a protrusion protruding downward.

[0011] In this manner, even if there is a protrusion protruding below the glass ribbon, which is formed, for example, when poor cutting or inability to cut occurs, the protrusion is detected by the sensor and the detection result is reflected in the cutting process, thereby effectively preventing the occurrence of vertical cracks in the glass ribbon due to the presence of the protrusion.

[0012] In the above configuration, a plurality of the sensors may be installed corresponding to a plurality of positions in the width direction of the glass ribbon.

[0013] In this manner, the cutting state is inspected at each of a plurality of locations in the width direction of the glass ribbon by a plurality of sensors, so that inspection by the sensors becomes precise and highly accurate.

[0014] In this configuration, the manner of the cutting process may be changed depending on the difference in the inspection results of the plurality of sensors.

[0015] In this way, the manner of the cutting process differs according to the differences in the cutting states inspected by the multiple sensors, so that the cutting process can be performed appropriately taking into account the states of each of the multiple locations.

[0016] In the above-described configuration, the plurality of sensors may have an inspection area at a position a predetermined length downward from a cutting position where the cutting process is performed in the second cutting step, and a first inspection result by the plurality of sensors may be obtained at a first time period until the glass ribbon is scheduled to reach the inspection area.

[0017] In this way, it is possible to obtain results of inspection of the states of the respective multiple locations of the glass ribbon by the multiple sensors, in comparison with a case where the glass ribbon has undergone a normal cutting process at the cutting position. In detail, by obtaining a first detection result at a first time period, it is possible to obtain information on the lower end portion of the glass ribbon.

[0018] In this configuration, if none of the plurality of sensors detects the glass ribbon during the first period, a second inspection result by the plurality of sensors is obtained during a second period following the first period, and if all of the plurality of sensors detect the glass ribbon during the second period, the glass ribbon may be cut over its entire width as the cutting process.

[0019] Here, when all of the multiple sensors do not detect the glass ribbon in the first period, it means that the glass ribbon has undergone a normal cutting process at the cutting position, or when the cut end of the glass ribbon after the cutting process is located above the cutting position. When this information is acquired, the process waits until all of the multiple sensors detect the presence of the glass ribbon in the second period, and when all of the multiple sensors detect this, the subsequent cutting process is performed on the glass ribbon. Here, the process waits until all of the multiple sensors detect the glass ribbon in order to properly cut the glass ribbon over its entire width in the subsequent cutting process. According to the configuration here, the glass ribbon can be cut to an appropriate length (for example, a length that is set in advance).

[0020] In the above-described configuration, when all of the plurality of sensors detect the glass ribbon during the first period, the glass ribbon may be cut across its entire width as the cutting process.

[0021] Here, the case where all of the multiple sensors detect the glass ribbon in the first period is the case where cutting failure occurs when the preceding cutting process is performed. When this information is acquired, it is preferable to immediately perform the cutting process after the detection by the sensors. In this way, it is possible to prevent the lower end of the glass ribbon from becoming unduly long downward over the entirety.

[0022] In the above-described configuration, if, in the first period, two or more sensors among the plurality of sensors detect the glass ribbon and the remaining one or more sensors do not detect the glass ribbon, a second inspection result by the plurality of sensors is obtained in a second period following the first period, and, in the second period, it is waited until the remaining one or more sensors detect the glass ribbon, and when the remaining one or more sensors detect the glass ribbon, the glass ribbon is cut over its entire width direction as the cutting process.

[0023] The reason why the glass ribbon is not immediately cut when it is detected in two or more locations in the width direction in the first period is that cutting the glass ribbon over the entire width direction can ensure ease and reliability of the cutting operation. In this case, the reason why the glass ribbon is waited for until one or more remaining sensors detect the glass ribbon in the second period is to wait until the glass ribbon can be appropriately cut over the entire width direction in the cutting process.

[0024] In the above-described configuration, when cutting the glass ribbon over its entire width as the cutting process, bending stress may be applied to the region of the glass ribbon to be cut.

[0025] In this way, the bending stress can be effectively utilized to cut the glass ribbon over its entire width, and the cutting process can be carried out smoothly and reliably.

[0026] In the above-described configuration, if, during the first period, one of the multiple sensors detects the glass ribbon and the remaining one or more sensors do not detect the glass ribbon, the cutting process may involve cutting only one location in the width direction of the glass ribbon corresponding to the one sensor.

[0027] In this way, when it is detected in the first period that the glass ribbon is present only at one of the multiple locations in the width direction, the glass ribbon is cut at only one location. Therefore, the glass ribbon can be cut more easily and quickly than when the glass ribbon is cut over its entire width direction.

[0028] In this configuration, the one location in the width direction of the glass ribbon may be one end portion in the width direction of the glass ribbon.

[0029] Here, both ends of the glass ribbon in the width direction have ears, and since the ears are thicker than the central region, a long narrow protrusion is likely to occur downward. When such a protrusion occurs at one end in the width direction, the protrusion can be cut off by a cutting process at an early stage. This makes it possible to efficiently cut off a particularly troublesome protrusion.

[0030] In these configurations, when the cutting process cuts the glass ribbon at only one location in the width direction, it is not necessary to apply bending stress to the region of the glass ribbon to be cut.

[0031] In this way, the time and effort required for applying bending stress is eliminated, and the cutting process can be carried out more quickly and simply.

[0032] A second aspect of the present invention devised to solve the above problems is a glass sheet manufacturing apparatus including a first cutting device that cuts, along the width direction, a glass ribbon that is being formed in a forming zone and moving continuously downward to cut out a glass sheet, and a second cutting device that is configured differently from the first cutting device and cuts the glass ribbon when the first cutting device is not in use, wherein the second cutting device is configured to inspect the state of the glass ribbon with a sensor and perform a cutting process of the glass ribbon based on the inspection result of the sensor.

[0033] This makes it possible to obtain the same effects as those of the previously described manufacturing method having substantially the same configuration as this manufacturing apparatus. Effect of the Invention

[0034] According to the present invention, when a second cutting process is performed instead of a first cutting process on a glass ribbon that is being formed and continuously moving downward, even if poor cutting or inability to cut occurs, it is possible to respond appropriately to these and prevent the occurrence of vertical cracks, etc. [Brief description of the drawings]

[0035] [Figure 1] 1 is a side view showing an overall configuration of a glass sheet manufacturing apparatus according to an embodiment of the present invention. [Diagram 2] 1 is a schematic front view showing a main part of a glass sheet manufacturing apparatus according to an embodiment of the present invention. [Diagram 3] FIG. 4 is an enlarged schematic plan view showing a second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged schematic plan view showing a second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Diagram 5] FIG. 4 is an enlarged side view showing a second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 6] FIG. 2 is a schematic front view showing a basic configuration when cutting a glass ribbon using a second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 7] 7(a) and (b) are schematic front views showing a first example of a specific mode when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 8] 8(a) and (b) are each a schematic front view showing a second example of a specific mode when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 9] 9(a) and (b) are schematic front views showing a third example of a specific mode when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 10] 10(a) and (b) are schematic front views showing a fourth example of a specific mode when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 11] 11(a) and (b) are schematic front views showing a fifth example of a specific mode when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 12] 12(a) and (b) are schematic front views showing a sixth example of a specific mode when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 13] 13(a) and (b) are schematic front views showing a first modified example of a specific aspect when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. [Figure 14] 14(a) and (b) are schematic front views showing a second modified example of a specific aspect when cutting a glass ribbon using the second cutting device in the glass sheet manufacturing apparatus according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0037] 1 is a side view showing an overall configuration of a glass sheet manufacturing apparatus according to the present embodiment. As shown in the drawing, the glass sheet manufacturing apparatus includes, as main components, a processing device 1 for a glass ribbon G, a first cutting device 2, and a second cutting device 3.

[0038] The processing device 1 includes a forming zone 11 for continuously forming a glass ribbon G, a heat treatment zone 12 for heat treating (slowly cooling) the glass ribbon G, a cooling zone 13 for cooling the glass ribbon G to approximately room temperature, and a conveying device 14 consisting of roller pairs R arranged in multiple stages above and below in each of the forming zone 11, the heat treatment zone 12, and the cooling zone 13.

[0039] The forming zone 11 and the heat treatment zone 12 are constituted by a furnace in which the periphery of the transport path of the glass ribbon G is surrounded by walls, and heating devices such as heaters for adjusting the temperature of the glass ribbon G are disposed at appropriate positions within the furnace. On the other hand, the cooling zone 13 is open to the external atmosphere at room temperature without the periphery of the transport path of the glass ribbon G being surrounded by walls, and no heating device such as a heater is disposed therein.

[0040] In the internal space of the forming zone 11, a forming body 15 is disposed, which forms a glass ribbon G from molten glass Gm by an overflow downdraw method. The molten glass Gm supplied to the forming body 15 overflows from a groove (not shown) formed in a top portion 15a of the forming body 15. The overflowing molten glass Gm flows along both side surfaces 15b, which have a wedge-shaped cross section, of the forming body 15 and joins at the lower end. In this way, a plate-shaped glass ribbon G is continuously formed. The continuously formed glass ribbon G is sent downward in a vertical position (preferably a vertical position).

[0041] The internal space of the heat treatment zone 12 has a predetermined temperature gradient downward. The glass ribbon G in the vertical position is heat treated (slowly cooled) so that the temperature decreases as it moves downward through the internal space of the heat treatment zone 12. This heat treatment reduces internal distortion of the glass ribbon G. The temperature gradient in the internal space of the heat treatment zone 12 is adjusted, for example, by a heating device provided on the inner wall surface of the heat treatment zone 12.

[0042] The multiple roller pairs R constituting the conveying device 14 clamp both widthwise ends of the glass ribbon G in a vertical position from both the front and back sides. The uppermost roller pair R arranged in the forming zone 11 is a cooling roller. Note that, in the internal space of the heat treatment zone 12, the multiple roller pairs R may include ones that do not clamp the side ends of the glass ribbon G. In other words, the opposing distance between the roller pairs R may be made larger than the thickness of both widthwise ends of the glass ribbon G, and the glass ribbon G may pass between the roller pairs R.

[0043] In this embodiment, both widthwise end portions of the glass ribbon G produced by the processing device 1 have portions (hereinafter also referred to as "ear portions") that are thicker than the widthwise central portion due to the influence of shrinkage during the molding process.

[0044] The first cutting device 2 is configured to cut the glass ribbon G in a vertical position below the processing device 1 in the width direction at predetermined lengths to sequentially cut out glass plates from the glass ribbon G. The glass plates become original glass plates (mother glass plates) from which one or more product glass plates are obtained in a later process by removing the edge portions. Here, the width direction is a direction perpendicular to the longitudinal direction (transport direction) of the glass ribbon G, and in this embodiment, substantially coincides with the horizontal direction.

[0045] As shown in FIGS. 1 and 2, the first cutting device 2 includes a scribe line forming device 21 and a breaking device 22.

[0046] The scribe line forming device 21 is a device that forms a scribe line S on a first main surface Ga of the glass ribbon G in a vertical position that has descended from the processing device 1 at a scribe line forming position P1. In this embodiment, the scribe line forming device 21 includes a wheel cutter 23 that forms a scribe line S on the first main surface Ga of the glass ribbon G along its width direction, and a support member 24 (e.g., a support bar or a support roller) that supports a second main surface (the surface opposite to the first main surface Ga) Gb of the glass ribbon G at a position corresponding to the wheel cutter 23. The scribe line S may be formed by irradiating a laser or the like.

[0047] The slicing device 22 is a device that slicing the glass ribbon G along the scribe line S at a slicing position P2 provided below the scribe line forming position P1 to cut out a glass sheet. In this embodiment, the slicing device 22 includes a slicing member 25 that abuts against the region where the scribe line S is formed from the second main surface Gb side, and a gripping mechanism 26 that grips a lower region of the glass ribbon G below the slicing position P2.

[0048] The breaking member 25 is composed of a plate-like body (plate) having a flat surface that contacts the entire width or a part of the width of the glass ribbon G. The contact surface of the breaking member 25 may be a curved surface that is curved in the width direction.

[0049] The gripping mechanism 26 includes chucks 27 disposed at multiple locations in the vertical direction at both widthwise ends of the glass ribbon G, and arms 28 (see FIG. 2) that hold the multiple chucks 27 at both widthwise ends. Note that the chucks 27 may be changed to another holding form, such as holding the glass ribbon G by negative pressure suction.

[0050] 1 and 2, the second cutting device 3 is disposed below the first cutting device 2, and when the first cutting device 2 is not in use, for example during maintenance, cuts the glass ribbon G that is being formed in the forming zone 11 and moves continuously downward. In the following description, the second main surface Gb side (the side indicated by the arrow X in FIG. 1) of the glass ribbon G is defined as the front side, and the first main surface Ga side (the side indicated by the arrow Y in FIG. 1) is defined as the rear side.

[0051] The second cutting device 3 includes a main body frame 31 consisting of a framework disposed behind the glass ribbon G. A pair of holding devices 32, a pair of cutting devices 33, and a stress applying device 34 are attached to the front end of the main body frame 31 in this order from above. Furthermore, the second cutting device 3 includes a sensor 35 installed behind the glass ribbon G.

[0052] The pair of holding devices 32 include holding members 36 arranged corresponding to both widthwise ends of the glass ribbon G, and each of these holding members 36 is rotatable around a rotation shaft 37 (see Figs. 3 and 4). Furthermore, each of these holding members 36 is changeable between a state in which it is retracted outward in the width direction from the glass ribbon G as shown in Fig. 3 (a state shown by a solid line in Fig. 5) and a state in which it supports the second main surface Gb of the glass ribbon G as shown in Fig. 4 (a state shown by a dashed line in Fig. 5).

[0053] The pair of cutting devices 33 includes rotary blades 38 arranged corresponding to both ends of the glass ribbon G in the width direction, and each of these rotary blades 38 is movable in the front-rear direction (a direction inclining upward toward the front) (see Figs. 2 and 5). Furthermore, each of these rotary blades 38 can be changed between a state in which it is retreated backward from the glass ribbon G as shown in Fig. 3 (a state shown by a solid line in Fig. 5) and a state in which it contacts both ends of the glass ribbon G in the width direction as shown in Fig. 4 (a state shown by a dashed line in Fig. 5). Furthermore, these rotary blades 38 are held at the same height position, and each of them can move and operate independently. When the rotary blade 38 is in contact with the glass ribbon G, it is possible to perform a process of inscribing a scribe line at the end of the glass ribbon G in the width direction and a process of cutting the end of the glass ribbon G in the width direction.

[0054] The stress applying device 34 has a pressing member 41 attached to the tip of a pair of swinging arms 40 that can swing around a support shaft 39 (see Figs. 1 and 2). The pressing member 41 is a roller-shaped member extending in the width direction, and is longer than the width direction length of the glass ribbon G. Furthermore, the pressing member 41 is changeable between a state in which it is retreated rearward from the glass ribbon G as shown in Fig. 3 (a state shown by a solid line in Fig. 5) and a state in which it presses the glass ribbon G as shown in Fig. 4 (a state shown by a dashed line in Fig. 5).

[0055] A plurality of sensors 35 are provided corresponding to a plurality of positions in the width direction of the glass ribbon G. In this embodiment, a total of three sensors 35 are provided at positions corresponding to both ends in the width direction of the glass ribbon G and at a position corresponding to the center in the width direction (see FIG. 2). These sensors 35 are fixed to the front end of the main body frame 31 so as to be aligned in a straight line in the width direction and are held at fixed positions. As the sensors 35, a laser sensor, an ultrasonic sensor, a thermosensor, or the like is used.

[0056] The basic cutting process by the second cutting device 3 is performed as follows. First, as shown by a solid line in FIG. 5, the holding member 36 rotates while the glass ribbon G is being formed and continuously moving downward. As a result, the holding member 36 is in a state in which it is possible to hold the second main surface Gb of the glass ribbon G as shown by a dashed line in the same figure. In this state, the pressing member 41 swings forward. As a result, the pressing member 41 presses the glass ribbon G as shown by a dashed line in the same figure, and applies bending stress to the region Gx of the glass ribbon G to be cut, that is, the peripheral region Gx of the cutting position P3 where the cutting is performed by the rotary blade 38. At this time, the holding member 36 holds the second main surface Gb of the glass ribbon G above the cutting position P3, and prevents the glass ribbon G from being displaced forward. In this state, the rotary blade 38 moves forward. As a result, the rotary blade 38 comes into contact with the first main surface Ga of the glass ribbon G at the cutting position P3 as shown by the dashed line in the figure, and carves a scribe line (initial crack) in the glass ribbon G. The initial crack is simultaneously carved at both ends of the glass ribbon G in the width direction by the pair of rotary blades 38. The carved position of the initial crack may be a position including the ear of the glass ribbon G, or may be a position not including the ear. Then, the glass ribbon G is cut by the initial crack progressing along the width direction of the glass ribbon G. The glass after the cut falls downward as unnecessary glass Gy and is collected in the collection area 42. Thereafter, the subsequent cutting process is performed on the glass ribbon G in the same manner. The three sensors 35 inspect the cutting state of the glass ribbon G that has been subjected to the preceding cutting process during a predetermined period until the subsequent cutting process is performed on the glass ribbon G.

[0057] Next, a method for producing a glass sheet using the glass sheet producing apparatus having the above-mentioned configuration will be described.

[0058] The glass sheet manufacturing method according to the present embodiment includes a forming step, a transporting step, a first cutting step, and a second cutting step.

[0059] The forming step is a step of forming a glass ribbon G in the forming zone 11 .

[0060] The conveying step is a step of conveying the formed glass ribbon G by the roller pair R of the conveying device 14. The conveying step includes a heat treatment step and a cooling step.

[0061] The heat treatment step is a step of carrying out a heat treatment on the glass ribbon G that has been subjected to the forming step in the heat treatment zone 12 while transporting the glass ribbon G.

[0062] The cooling step is a step in which the glass ribbon G that has been subjected to the heat treatment step is cooled while being transported in the cooling zone 13.

[0063] The first cutting step is a step in which the glass ribbon G that has been subjected to the cooling step is conveyed and cut in the width direction by a first cutting device 2 to obtain a glass plate.

[0064] More specifically, as shown in FIG. 1 and FIG. 2, in the first cutting step, first, the wheel cutter 23 and the support member 24 move following the glass ribbon G moving continuously downward, and form a scribe line S in the entire area or part of the width direction of the glass ribbon G. In this embodiment, the scribe line S is also formed in the ear portion having a relatively large thickness. Next, after the plurality of chucks 27 grip the glass ribbon G, the arm 28 moves the plurality of chucks 27 following the glass ribbon G. At this time, the bending member 25 also moves following the glass ribbon G. During these movements, the arm 28 performs an operation for bending the glass ribbon G with the bending member 25 as a fulcrum (operation in the B direction shown in FIG. 1). As a result, bending stress is applied to the scribe line S and its vicinity, and the glass ribbon G is bent and broken in the width direction along the scribe line S. As a result of cutting by this bending and breaking, a glass plate is cut out from the glass ribbon G.

[0065] The second cutting step is a step of cutting the glass ribbon G using the second cutting device 3 when the first cutting device 2 is not used.

[0066] For example, in the second cutting process, after the glass ribbon G has undergone a preceding cutting process, the cutting state of the glass ribbon G is inspected by a sensor 35, and a subsequent cutting process is performed on the glass ribbon G based on the inspection results of the sensor 35.

[0067] In this embodiment, as described above, the three sensors 35 are held at fixed positions. Therefore, as shown in Fig. 6, the inspection area E by the three sensors 35 is separated downward by a predetermined length L1 from the cutting position P3 where the glass ribbon G is cut by the rotary blade 38. Therefore, the three sensors 35 according to this embodiment inspect the cutting state of the glass ribbon G during the process in which the glass ribbon G cut at the cutting position P3 approaches the inspection area E and passes through it.

[0068] Specifically, the three sensors 35 inspect whether or not the glass ribbon G has an uncut portion (details of which will be described later) after the glass ribbon G has undergone a preceding cutting process. The uncut portion is a protruding portion of the glass ribbon G that protruded downward from the cutting position P3 when the glass ribbon G has undergone a preceding cutting process.

[0069] In this embodiment, a first inspection result is obtained by the three sensors 35 at a first time when the moving length of the glass ribbon G from the time when the preceding cutting process is completed reaches a predetermined length L1, and a second inspection result is obtained by the three sensors 35 at a second time following the first time, as necessary. The first inspection result and the second inspection result may be obtained continuously from the time when the preceding cutting process is completed, or may be obtained at a predetermined time interval. Here, the first and second inspection results by the three sensors 35 may be obtained by an operator or the like, or may be obtained by an automatic control means such as a personal computer. An example of a specific mode when performing such an operation is shown below.

[0070] 7(a) and (b) show a first example of the specific embodiment. In this first example, as shown in FIG. 7(a), when the glass ribbon G has undergone the preceding cutting process, the glass ribbon G is cut in a straight line in the width direction at the cutting position P3. This means that the glass ribbon G has been cut normally. When the glass ribbon G moves downward, at the first time, as shown by the solid line in FIG. 7(b), none of the three sensors 35 detect the glass ribbon G. When this information is acquired, at the second time, the process waits until all of the three sensors 35 detect the glass ribbon G. Then, when all of the three sensors 35 detect the glass ribbon G at the second time, for example, as shown by the dashed line in FIG. 7(b), when the glass ribbon G reaches a preset set position P4, the glass ribbon G is cut at the cutting position P3 over the entire width direction as the subsequent cutting process. This set position P4 is a position that is a predetermined length L2 longer than L1 downward from the cutting position P3. As a result, the glass ribbon G is cut to a preset length L2. This subsequent cutting process is performed by forming an initial crack with the pair of rotary blades 38 in a state in which bending stress is applied to the region Gx of the glass ribbon G to be cut by the holding member 36 and the pressing member 41. When the glass ribbon G is normally cut, all of the three sensors 35 detect the glass ribbon G at the timing when the first period changes to the second period.

[0071] FIG. 8 shows a second example of the specific embodiment. In this second example, when the glass ribbon G has undergone the preceding cutting process, the glass ribbon G has not been cut at the cutting position P3. Therefore, when the glass ribbon G moves downward, at the first time, all of the three sensors 35 detect the glass ribbon G as shown by the solid line in the figure. When this information is acquired, the glass ribbon G is immediately cut over the entire width direction as the subsequent cutting process. Note that, when this information is acquired, if the glass ribbon G has not reached the set position P4, the subsequent cutting process may be performed on the glass ribbon G at the time when it reaches the set position P4 as shown by the dashed line in the figure. The subsequent cutting process in this second example is also performed using the holding member 36, the pressing member 41, and a pair of rotary blades 38, as in the first example described above.

[0072] 9(a) and (b) show a third example of the specific embodiment. In this third example, as shown in FIG. 9(a), when the glass ribbon G has undergone the preceding cutting process, an uncut portion Gc protruding downward from the cutting position P3 remains in more than half of the width direction of the glass ribbon G (more than half on the left side). When this glass ribbon G moves downward, in the first period, as shown by the solid line in FIG. 9(b), a total of two sensors 35 at the left end and the center in the width direction detect the glass ribbon G. When this information is acquired, in the second period, the sensor 35 at the right end in the width direction detects the glass ribbon G. Then, in the second period, as shown by the dashed line in FIG. 9(b), when the sensor 35 at the right end in the width direction detects the glass ribbon G, this information is acquired, and the glass ribbon G is cut at the cutting position P3 over the entire width direction length as the subsequent cutting process. In this case, the subsequent cutting process may be immediately performed on the glass ribbon G when the sensor 35 at the right end in the width direction detects the glass ribbon G. In order to achieve this, it is necessary to configure the pressing member 41 to press the glass ribbon G at a position above the inspection areas E of the three sensors 35. In addition, if the bottom end Gcx of the uncut portion Gc of the glass ribbon G has not reached the set position P4 as shown in the figure when it becomes possible to perform the subsequent cutting process, the subsequent cutting process may be performed on the glass ribbon G when it reaches the set position P4. The subsequent cutting process in this third example is also performed using the holding member 36, the pressing member 41, and a pair of rotary blades 38, as in the first example described above.

[0073] 10(a) and (b) show a fourth example of the specific embodiment. The fourth example differs from the third example in that, as shown in FIG. 10(a), when the glass ribbon G has undergone the preceding cutting process, an uncut portion Gc protruding downward from the cutting position P3 remains at each of both ends in the width direction of the glass ribbon G. Therefore, when the glass ribbon G moves downward, in the first period, as shown by the solid line in FIG. 10(b), a total of two sensors 35 at both ends in the width direction detect the glass ribbon G. After acquiring this information, the operation of performing the subsequent cutting process on the glass ribbon G at the second period is performed in the same manner as the third example described above.

[0074] 11(a) and (b) show a fifth example of the specific embodiment. In this fifth example, as shown in FIG. 11(a), when the glass ribbon G has undergone the preceding cutting process, an uncut portion Gc protruding downward from the cutting position P3 remains only at one end (left end) in the width direction of the glass ribbon G. When this glass ribbon G moves downward, at the first time, as shown by the solid line in FIG. 11(b), only the sensor 35 at the left end in the width direction detects the glass ribbon G. When this information is acquired, at the second time, the uncut portion Gc alone is cut along the width direction by the rotary blade 38 as the subsequent cutting process, either before or after the total of two sensors 35 at the center and right end in the width direction detect the glass ribbon G. When cutting only the uncut portion Gc in this way, it is necessary to make the rotary blade 38 movable in the vertical direction and move the rotary blade 38 to a position where only the uncut portion Gc can be cut. Therefore, in this case, it is not necessary to operate the holding member 36 and the pressing member 41. Also in this case, if the lowermost end Gcx of the uncut portion Gc of the glass ribbon G has not reached the set position P4 as shown by the dashed line in Fig. 1(b) when it becomes possible to perform the subsequent cutting process, only the uncut portion Gc may be cut at the time of reaching the set position P4. Furthermore, if the two sensors 35 at the widthwise center and right end do not detect the glass ribbon G for a predetermined period in the second period, the subsequent cutting process may be performed on the glass ribbon G.

[0075] 12(a) and (b) show a sixth example of the specific embodiment. In this sixth example, as shown in FIG. 12(a), when the glass ribbon G has undergone the preceding cutting process, the glass ribbon G has a remaining uncut portion Gc protruding downward from the cutting position P3 and a chipped portion Gd recessed upward from the cutting position P3. When this glass ribbon G moves downward, in the first period, as shown by the solid line in FIG. 12(b), a total of two sensors 35 detect the glass ribbon G. When this information is acquired, in the second period, the subsequent cutting process may be performed on the glass ribbon G in the same manner as in the third example described above, after waiting until the remaining sensor 35 detects the glass ribbon G, but the following response may also be made. That is, in the second period, when the remaining sensor 35 does not detect the glass ribbon G within a predetermined time set in advance, the subsequent cutting process is performed on the glass ribbon G in the same manner as in the third example described above after the predetermined time has elapsed. The predetermined time here is set, for example, based on the time when the glass ribbon G has undergone the preceding cutting process. Also in this case, when the lowermost end Gcx of the uncut portion Gc of the glass ribbon G reaches the set position P4, the glass ribbon G may be subjected to the subsequent cutting process in the same manner as in the third example described above.

[0076] The above specific embodiment has been described with reference to an example in which the glass ribbon G is cut using three sensors 35, but the glass ribbon G can also be cut using two sensors 35. In this case, the ears at both ends in the width direction of the glass ribbon G are thicker than the central portion, so that long, narrow uncut portions tend to remain around the ears, particularly at the lower portion. For this reason, of the three sensors 35 described above, the sensor 35 at the center in the width direction may be eliminated, and a total of two sensors 35 at both ends in the width direction may be used. An example of a specific embodiment in this case (hereinafter referred to as a modified example) is shown below.

[0077] 13(a) and (b) show a first modified example. In this first modified example, as shown in FIG. 13(a), when the glass ribbon G has undergone a preceding cutting process, a narrow uncut portion Gc protruding downward from the cutting position P3 remains at one end (left end) in the width direction of the glass ribbon G. When this glass ribbon G moves downward, at a first time, as shown by a solid line in FIG. 13(b), the sensor 35 at the left end in the width direction detects the glass ribbon G. When this information is acquired, in the same manner as the fifth example shown in FIG. 11(a) and (b), only the uncut portion Gc is cut along the width direction by the rotary blade 38 as a subsequent cutting process, either before or after the sensor 35 at the right end in the width direction detects the glass ribbon G. Also in this case, when it becomes possible to perform the subsequent cutting process, if the lowermost end Gcx of the remaining cut portion Gc of the glass ribbon G has not reached the set position P4, as shown by the dotted line in Figure (b), only the remaining cut portion Gc may be cut when it reaches the set position P4.

[0078] 14(a) and (b) show a second modified example. In this second modified example, as shown in FIG. 14(a), when the glass ribbon G has undergone a preceding cutting process, narrow uncut portions Gc protruding downward from the cutting position P3 remain at both ends in the width direction of the glass ribbon G. When this glass ribbon G moves downward, at a first time, as shown by a solid line in FIG. 14(b), the sensors 35 at both ends in the width direction detect the glass ribbon G. When this information is acquired, after a predetermined time has elapsed, the subsequent cutting process is performed on the glass ribbon G in the same manner as in the third example shown in FIG. 9(a) and (b). The predetermined time here is set, for example, based on the time when the glass ribbon G has undergone a preceding cutting process. Also in this case, when it becomes possible to perform the subsequent cutting process, if the lowermost end Gcx of the remaining cut portion Gc of the glass ribbon G has not reached the set position P4, as shown by the dotted line in Figure (b), only the remaining cut portion Gc may be cut when it reaches the set position P4.

[0079] According to the glass sheet manufacturing apparatus and the manufacturing method thereof according to the embodiment of the present invention having the above-mentioned configuration, the following effects can be obtained.

[0080] In the above embodiment, when the first cutting step is performed, the wheel cutter 23, the support member 24, the arm 28, the multiple chucks 27, and the breaker member 25 move following the glass ribbon G, so that the glass ribbon G can be cut accurately with good quality, although the configuration of the first cutting device 2 is complicated. In contrast, when the second cutting step is performed, each component of the second cutting device 3 does not move following the glass ribbon G. Therefore, since the second cutting device 3 has a much simpler configuration than the first cutting device 2, poor cutting or inability to cut is likely to occur in the second cutting step. Therefore, in the second cutting step, various measures as already described are taken to avoid such problems. As a result, it is possible to perform appropriate cutting operations in both the first cutting step and the second cutting step.

[0081] In the above embodiment, when the second cutting process is performed instead of the first cutting process, the state of the lower end of the glass ribbon G after the preceding cutting process is inspected by the sensor 35, so that it is possible to appropriately respond to the occurrence of poor cutting, inability to cut, and the like. In detail, when the lower end of the glass ribbon G becomes unduly long downward due to poor cutting, inability to cut, and the like occurring during the preceding cutting process, the sensor 35 quickly and accurately detects the fact, and the detection result is reflected in the subsequent cutting process. Therefore, in the subsequent cutting process, it is possible to perform appropriate cutting so that the lower end of the glass ribbon G does not get in the way. This makes it possible to avoid problems such as the lower end of the glass ribbon G getting caught on components of the second cutting device 3 or colliding with a dead end part of the movement path of the glass ribbon G during the process in which the glass ribbon G continuously moves downward. That is, when the lower end of the glass ribbon G is unduly long downward, when the pressing member 41 of the second cutting device 3 has not returned to the retracted position, the lower end of the glass ribbon G may get caught on the swinging arm 40 supporting the pressing member 41, and the like. Similarly, if the lower end of the glass ribbon G is unduly long downward, the lower end of the glass ribbon G may collide with the collection area 42 for collecting the unwanted glass Gy. In the above embodiment, it is possible to prevent such situations from occurring. As a result, it is possible to prevent the occurrence of vertical cracks in the glass ribbon G.

[0082] The second cutting step in the above embodiment is to inspect whether or not there is an uncut portion Gc in the glass ribbon G after the glass ribbon G has undergone a preceding cutting process. Therefore, even if there is an uncut portion Gc in the glass ribbon G, the uncut portion Gc is detected by the sensor 35, and the detection result is reflected in the subsequent cutting process, so that it is possible to effectively prevent the occurrence of vertical cracks in the glass ribbon G due to the presence of the uncut portion Gc.

[0083] In this case, the above-mentioned uncut portion is a protruding portion of the glass ribbon G that protruded downward from the cutting position P3 when the glass ribbon underwent the preceding cutting process. According to this, when the glass ribbon G has undergone a normal cutting process at the cutting position P3, a protruding portion protruding downward from the cutting position P3 is not formed in the glass ribbon G. In contrast, when poor cutting or inability to cut occurs, a protruding portion protruding downward from the cutting position P3, that is, an uncut portion Gc remains in the glass ribbon G. Therefore, by the sensor 35 inspecting the presence or absence of the uncut portion Gc, it is possible to accurately know whether or not the glass ribbon has undergone a normal cutting process, and accordingly, it is possible to accurately determine whether or not the second cutting device 3 needs to be replaced.

[0084] In the second cutting step of the above embodiment, a plurality of (three or two) sensors 35 are installed corresponding to a plurality of positions in the width direction of the glass ribbon G. Therefore, the plurality of sensors 35 can inspect the cutting state for each of the plurality of positions in the width direction of the glass ribbon G, and therefore inspection by the sensors 35 becomes precise and highly accurate.

[0085] In the second cutting step of the above embodiment, the manner of the subsequent cutting process is changed according to the difference in the inspection results of the multiple sensors 35. Therefore, the manner of the subsequent cutting process can be changed according to the difference in the cutting state inspected by each of the multiple sensors 35, and the subsequent cutting process can be appropriately performed taking into account the cutting state of each of the multiple locations.

[0086] In the second cutting step of the above embodiment, the multiple sensors 35 have an inspection area at a position that is a predetermined length L1 downward from the cutting position P3. Then, a first inspection result is obtained by the multiple sensors 35 at a first time when the moving length of the glass ribbon G from the time when the preceding cutting process is performed is expected to reach the predetermined length L1. In addition, a second inspection result is obtained by the multiple sensors 35 at a second time following the first time, as necessary. In this way, the results of the multiple sensors 35 inspecting the cutting state of each of the multiple locations of the glass ribbon G can be obtained in comparison with the case where the glass ribbon G has been normally cut at the cutting position P3. In detail, by obtaining the first detection result at the first time, it is possible to know whether or not the lower end of the glass ribbon G is unduly long downward. In addition, by obtaining the second detection result at the second time, it is possible to know the appropriate time for performing the subsequent cutting process on the glass ribbon G. This allows the inspection by the multiple sensors 35 to be performed more precisely, and the inspection results are effectively utilized.

[0087] In the second cutting step of the above embodiment, when the glass ribbon G is cut over its entire width direction as a subsequent cutting process, a bending stress is applied to the region Gx to be cut of the glass ribbon G. Therefore, the glass ribbon G can be cut over its entire width direction by effectively utilizing the bending stress, and the subsequent cutting process can be performed smoothly and reliably.

[0088] In the second cutting step of the above embodiment, when cutting only one location in the width direction of the glass ribbon G as the subsequent cutting process, bending stress is not applied to the region Gx to be cut of the glass ribbon G. Therefore, the effort of applying bending stress is saved, and the subsequent cutting process can be performed early and simply.

[0089] The above describes the glass sheet manufacturing apparatus and the manufacturing method thereof according to an embodiment of the present invention. However, the embodiment of the present invention is not limited to this, and various modifications are possible without departing from the gist of the present invention.

[0090] In the above embodiment, the glass ribbon G is formed by the overflow downdraw method. However, it may be formed by other downdraw methods such as a slot downdraw method or a redraw method.

[0091] In the above embodiment, in the first cutting step, the glass ribbon G is cut by bending along the scribe lines S, but it may be cut by other methods such as laser cleavage or laser melting.

[0092] In the above embodiment, the second cutting device 3 is disposed below the first cutting device 2, but these devices 2, 3 may be disposed in parallel so as to overlap in the vertical direction. In this case, the main body frame 31 of the second cutting device 3 is held in a fixed position, and when the first cutting device 2 is in use, the holding member 36, the rotary blade 38, and the pressing member 41 are retreated to positions where they do not interfere with the operation of the first cutting device 2.

[0093] In the above embodiment, the rotary blade 38 is used to cut the glass ribbon G, but the present invention is not limited to this as long as it has a cutting edge.

[0094] In the above embodiment, two or three sensors 35 are arranged in the width direction, but four or more sensors 35 may be arranged in the width direction.

[0095] In the above embodiment, there is a preceding cutting process, but it may be, for example, an early stage of forming the glass ribbon G and not yet cutting the glass ribbon G. In that case, the starting point of the first period may be, for example, the time point when the leading end of the glass ribbon G reaches a position where it coincides with the holding member 36 of the second cutting device 3 in the height direction. [Explanation of symbols]

[0096] 1 Glass ribbon processing equipment 2 First cutting device 3 Second cutting device 11 Forming Zone 31 Main frame 32 Holding device 34 Stress Applicator 35 Sensors 36 Retaining member 38 Rotary Blade 40 Swing Arm 41 Pressing member E Sensor inspection area G Glass ribbon Gc Remaining part Gm Molten Glass Gx Area of ​​glass ribbon to be cut P3 cutting position

Claims

1. A glass sheet manufacturing method comprising: a first cutting step of cutting a glass ribbon, which is being formed in a forming zone and moving downward continuously, along a width direction to cut out a glass sheet; and a second cutting step of cutting the glass ribbon using an apparatus having a configuration different from that of an apparatus used in the first cutting step when the first cutting step is not performed, In the second cutting step, a state of the glass ribbon is inspected by a sensor, and a cutting process of the glass ribbon is performed based on an inspection result of the sensor, The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors have an inspection area at a position a predetermined length below a cutting position where a cutting process is performed in the second cutting step, and a first inspection result is obtained by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area, A glass plate manufacturing method characterized in that, if none of the plurality of sensors detects the glass ribbon during the first period, a second inspection result is obtained by the plurality of sensors during a second period following the first period, and, if all of the plurality of sensors detect the glass ribbon during the second period, the glass ribbon is cut over its entire width as the cutting process.

2. A glass sheet manufacturing method comprising: a first cutting step of cutting a glass ribbon, which is being formed in a forming zone and moving downward continuously, along a width direction to cut out a glass sheet; and a second cutting step of cutting the glass ribbon using an apparatus having a configuration different from that of an apparatus used in the first cutting step when the first cutting step is not performed, In the second cutting step, a state of the glass ribbon is inspected by a sensor, and a cutting process of the glass ribbon is performed based on an inspection result of the sensor, The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors have an inspection area at a position a predetermined length below a cutting position where a cutting process is performed in the second cutting step, and a first inspection result is obtained by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area, A glass sheet manufacturing method characterized in that, when all of the plurality of sensors detect the glass ribbon during the first period, the glass ribbon is cut across its entire width as the cutting process.

3. A glass sheet manufacturing method comprising: a first cutting step of cutting a glass ribbon, which is being formed in a forming zone and moving downward continuously, along a width direction to cut out a glass sheet; and a second cutting step of cutting the glass ribbon using an apparatus having a configuration different from that of an apparatus used in the first cutting step when the first cutting step is not performed, In the second cutting step, a state of the glass ribbon is inspected by a sensor, and a cutting process of the glass ribbon is performed based on an inspection result of the sensor, The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors have an inspection area at a position a predetermined length below a cutting position where a cutting process is performed in the second cutting step, and a first inspection result is obtained by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area, a second inspection result obtained by the sensors during a second period following the first period when two or more of the plurality of sensors detect the glass ribbon and one or more remaining sensors do not detect the glass ribbon during the first period; a second inspection result obtained by the sensors during the second period is waited until the one or more remaining sensors detect the glass ribbon during the second period; and when the one or more remaining sensors detect the glass ribbon, the glass ribbon is cut over its entire width as the cutting process.

4. The method for manufacturing a glass sheet according to any one of claims 1 to 3, wherein when the glass ribbon is cut over its entire width as the cutting process, a bending stress is applied to a region of the glass ribbon to be cut.

5. A glass sheet manufacturing method comprising: a first cutting step of cutting a glass ribbon, which is being formed in a forming zone and moving downward continuously, along a width direction to cut out a glass sheet; and a second cutting step of cutting the glass ribbon using an apparatus having a configuration different from that of an apparatus used in the first cutting step when the first cutting step is not performed, In the second cutting step, a state of the glass ribbon is inspected by a sensor, and a cutting process of the glass ribbon is performed based on an inspection result of the sensor, The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors have an inspection area at a position a predetermined length below a cutting position where a cutting process is performed in the second cutting step, and a first inspection result is obtained by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area, A glass plate manufacturing method characterized in that, during the first period, if one of the plurality of sensors detects the glass ribbon and the remaining one or more sensors do not detect the glass ribbon, the cutting process involves cutting only one location in the width direction of the glass ribbon corresponding to the one sensor.

6. The method for manufacturing a glass sheet according to claim 5 , wherein the one location in the width direction of the glass ribbon is one end portion in the width direction of the glass ribbon.

7. The method for manufacturing a glass sheet according to claim 5 or 6, wherein when the cutting process cuts the glass ribbon at only one location in the width direction, no bending stress is applied to the region of the glass ribbon to be cut.

8. The method for manufacturing a glass sheet according to any one of claims 1 to 7, wherein the sensor inspects whether or not the glass ribbon has a protruding portion protruding downward.

9. 9. The method for producing a glass sheet according to claim 1, wherein a mode of the cutting process is changed depending on differences in the inspection results of the plurality of sensors.

10. A glass sheet manufacturing apparatus including: a first cutting device that cuts a glass ribbon, which is formed in a forming zone and moves continuously downward, along a width direction to cut out a glass sheet; and a second cutting device that is configured differently from the first cutting device and cuts the glass ribbon when the first cutting device is not used, The second cutting device is configured to inspect a state of the glass ribbon by a sensor and perform a cutting process of the glass ribbon based on an inspection result of the sensor; The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors has an inspection area at a position spaced a predetermined length downward from a cutting position where a cutting process is performed by the second cutting device, and is configured to obtain a first inspection result by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area; The glass sheet manufacturing apparatus is characterized in that, if none of the plurality of sensors detects the glass ribbon during the first period, a second inspection result is obtained by the plurality of sensors during a second period following the first period, and if all of the plurality of sensors detect the glass ribbon during the second period, the glass ribbon is cut over its entire width as the cutting process.

11. A glass sheet manufacturing apparatus including: a first cutting device that cuts a glass ribbon, which is formed in a forming zone and moves continuously downward, along a width direction to cut out a glass sheet; and a second cutting device that is configured differently from the first cutting device and cuts the glass ribbon when the first cutting device is not used, The second cutting device is configured to inspect a state of the glass ribbon by a sensor and perform a cutting process of the glass ribbon based on an inspection result of the sensor; The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors has an inspection area at a position spaced a predetermined length downward from a cutting position where a cutting process is performed by the second cutting device, and is configured to obtain a first inspection result by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area; The glass sheet manufacturing apparatus is characterized in that, when all of the plurality of sensors detect the glass ribbon during the first period, the glass ribbon is cut across its entire width as the cutting process.

12. A glass sheet manufacturing apparatus including: a first cutting device that cuts a glass ribbon, which is formed in a forming zone and moves continuously downward, along a width direction to cut out a glass sheet; and a second cutting device that is configured differently from the first cutting device and cuts the glass ribbon when the first cutting device is not used, The second cutting device is configured to inspect a state of the glass ribbon by a sensor and perform a cutting process of the glass ribbon based on an inspection result of the sensor; The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors has an inspection area at a position spaced a predetermined length downward from a cutting position where a cutting process is performed by the second cutting device, and is configured to obtain a first inspection result by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area; the glass ribbon is cut across its entire width as the cutting process, when two or more of the plurality of sensors detect the glass ribbon during the first period and the remaining one or more sensors do not detect the glass ribbon, a second inspection result is obtained by the sensors during a second period following the first period, the glass ribbon is cut across its entire width as the cutting process, and the glass ribbon is cut across its entire width as the cutting process, when the remaining one or more sensors detect the glass ribbon during the second period.

13. A glass sheet manufacturing apparatus including: a first cutting device that cuts a glass ribbon, which is formed in a forming zone and moves continuously downward, along a width direction to cut out a glass sheet; and a second cutting device that is configured differently from the first cutting device and cuts the glass ribbon when the first cutting device is not used, The second cutting device is configured to inspect a state of the glass ribbon by a sensor and perform a cutting process of the glass ribbon based on an inspection result of the sensor; The sensor is provided in a plurality of locations corresponding to a plurality of locations in the width direction of the glass ribbon, The plurality of sensors has an inspection area at a position spaced a predetermined length downward from a cutting position where a cutting process is performed by the second cutting device, and is configured to obtain a first inspection result by the plurality of sensors at a first time period until the glass ribbon is scheduled to reach the inspection area; The glass sheet manufacturing apparatus is characterized in that, during the first period, when one of the plurality of sensors detects the glass ribbon and the remaining one or more sensors do not detect the glass ribbon, the cutting process cuts only one location in the width direction of the glass ribbon corresponding to the one sensor.

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