Glass plate manufacturing method and manufacturing device thereof

Abstract

The present invention includes: a cutting step of cutting a glass ribbon (G) moving downward in a vertical position along the width direction of the glass ribbon at a standard cutting length (L0) to obtain a glass sheet (g); and a judging step of judging the presence or absence of breakage in at least one of the glass ribbon (G) and the glass sheet (g) after the cutting step. If the breakage in the judging step is determined to be present, the glass ribbon (G) is cut at an extended cutting length (L1) longer than the standard cutting length (L0) in the next cutting step.

Description

Technical Field

[0001] The present invention relates to a method for producing a glass sheet, and a manufacturing apparatus thereof, for obtaining a glass sheet by cutting a glass ribbon moving downward (moving downward) in a vertical posture at a standard cutting length along the width direction of the glass ribbon. Background Art

[0002] As is well known, in the field of glass sheet production, a glass sheet is cut out from a glass ribbon formed by a downdraw method and moving downward. Specific examples of such a method and apparatus for producing a glass sheet include those disclosed in Patent Document 1.

[0003] The device disclosed in this publication includes: a scoring mechanism that forms a score line on a glass ribbon moving downward in a longitudinal position; a breaking rod (a fulcrum rod in this publication) that presses against the score line-forming region of the glass ribbon; and a supporting mechanism (a breaking arm in this publication) that supports the portion of the glass ribbon below the score line. Furthermore, the method disclosed in this publication for using this device to cut a glass sheet involves, after forming a score line along the width of the glass ribbon using the scoring mechanism, first pressing the breaking rod against the score line-forming region of the glass ribbon. Next, the supporting mechanism, which is supporting the glass ribbon, is activated to bend the score line-forming region using the breaking rod as a fulcrum. This results in the glass ribbon being broken along the score line, and a glass sheet being cut from the glass ribbon.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-90446 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] However, if a cut failure occurs during the aforementioned cutting process, the lower end of the glass ribbon remaining after the glass sheets have been cut may develop damage, such as cracks or chips. If the glass ribbon is cut again using the same standard cutting length as in the case of no breakage, a longitudinal crack may develop during the cutting process, where the breakage in the glass ribbon propagates upward. If this longitudinal crack propagates upward beyond the cut point (e.g., the score line) of the glass ribbon, it may be impossible to cut a normal, unbroken glass sheet for a long period of time. Furthermore, in the worst case, the longitudinal crack may eventually lead to damage to the entire glass ribbon over time, ultimately making it impossible to cut a glass sheet from the glass ribbon.

[0009] An object of the present invention is to reliably suppress the occurrence of longitudinal cracks in a glass ribbon when a glass sheet is cut out from the glass ribbon.

[0010] Solutions to Problems

[0011] (1) The present invention, which is made to solve the above-mentioned problems, is a method for manufacturing a glass plate, including a cutting process of cutting a glass ribbon moving downward in a longitudinal posture along the width direction of the glass ribbon at a standard cutting length to obtain a glass plate, and the manufacturing method of the glass plate is characterized in that the manufacturing method of the glass plate includes a judgment process, wherein the judgment process uses at least one of the lower end portion of the glass ribbon and the upper end portion of the glass plate after being cut in the cutting process as a judgment object, and judges whether the judgment object is damaged. When it is determined in the judgment process that the judgment object is damaged, the glass ribbon is cut at an extended cutting length longer than the standard cutting length in the next cutting process.

[0012] If the lower end of the glass ribbon cut in the cutting process is damaged, the upper end of the glass sheet separated from the glass ribbon often also develops damage at a location corresponding to the damage in the glass ribbon. Therefore, in the above-described configuration, to determine whether the lower end of the glass ribbon cut in the cutting process is damaged, the determination step uses at least one of the lower end of the glass ribbon cut in the cutting process and the upper end of the glass sheet as the determination target, and determines whether the determination target is damaged. Furthermore, if the determination step determines that the determination target is damaged, the glass ribbon is cut in the next cutting process using an extended cutting length that is longer than the standard cutting length. This allows the damaged lower end to be fully separated downward from the cutting position of the glass ribbon in the next cutting process. Consequently, longitudinal cracking of the glass ribbon beyond the cutting position can be reliably prevented.

[0013] (2) In the configuration of (1) above, preferably, in the determination step, the determination target is measured by a sensor, and the presence or absence of damage to the determination target is determined based on the measurement result of the sensor.

[0014] In this manner, the presence or absence of damage to the determination target can be automatically determined.

[0015] (3) In the configuration of (2) above, it is preferable that the sensor measures the widthwise end portion of the determination target.

[0016] The widthwise ends of a glass ribbon generally include tabs that are thicker than the widthwise center. Furthermore, when the glass ribbon is cut (particularly broken) near the cutting position without the tabs, longitudinal cracks that extend beyond the cutting position are likely to occur in the glass ribbon. Therefore, as in the above-described configuration, it is preferable that the sensor measures the widthwise end of the glass ribbon to determine whether there is damage to the widthwise end of the glass ribbon.

[0017] (4) In the configuration of (2) or (3) above, it is preferred that the sensor measures the widthwise end portions and the widthwise center portion of the determination target.

[0018] When a glass ribbon is cut (particularly broken) near a cutting position while being damaged in the widthwise center, longitudinal cracks may occur in the glass ribbon beyond the cutting position. Therefore, as in the above-described configuration, it is preferable that the sensor measures both the widthwise end portions and the widthwise center portion of the determination target, thereby determining the presence or absence of damage in the widthwise center portion in addition to the widthwise end portions of the determination target.

[0019] (5) In any one of the above-mentioned structures (1) to (4), it is preferable that a value obtained by subtracting the standard cut length from the extended cut length is 0.05 m or more and 4.0 m or less.

[0020] If the value obtained by subtracting the standard cutting length from the extended cutting length (i.e., extended cutting length - standard cutting length) is set to 0.05 m or more, the damaged portion can be sufficiently separated downward from the cut position of the glass ribbon. On the other hand, if (extended cutting length - standard cutting length) is set to 4.0 m or less, the undue lengthening of the cutting length can be suppressed, thereby facilitating the securing of space during cutting.

[0021] (6) In any one of the above structures (1) to (4), it is preferable that the extended cutting length is 1.02 times or more and 4.1 times or less of the standard cutting length.

[0022] When the extended cutting length is set to 1.02 times or more of the standard cutting length, the damaged portion can be sufficiently separated downward from the cut position of the glass ribbon. On the other hand, when the extended cutting length is set to 4.1 times or less of the standard cutting length, the undue lengthening of the cutting length can be suppressed, thereby facilitating the securing of space during cutting.

[0023] (7) In any one of the above-mentioned configurations (1) to (6), in the cutting step, the length of the extended cutting length may be adjusted according to the type of damage to be determined.

[0024] In this way, the length of the glass sheet cut with the extended cutting length can be set to the optimal length according to the breakage pattern. Therefore, even if the glass sheet cut with the extended cutting length is discarded, waste of glass can be minimized.

[0025] (8) In the configuration of (7) above, in the cutting step, the length of the extended cutting length may be adjusted according to at least one of the position and size of the damage to be determined.

[0026] When considering the size of the breakage as the type of damage, for example, if the breakage is large, the extended cut length can be longer, while if the breakage is small, the extended cut length can be shorter. Furthermore, when considering the location of the breakage as the type of damage, for example, if the breakage is located at a location with a high likelihood of negative impact, the extended cut length can be longer, while if the breakage is located at a location with a low likelihood of negative impact, the extended cut length can be shorter. In other words, the length of a glass sheet cut with the extended cut length can be set to the optimal length corresponding to the location and size of the breakage. Therefore, even if a glass sheet cut with the extended cut length is discarded, glass waste can be minimized.

[0027] (9) In any of the above structures (1) to (8), it is preferred that the cutting process includes: a scoring process of forming a scoring line on the glass ribbon along the width direction of the glass ribbon; and a breaking process of breaking the glass ribbon along the scoring line to cut out a glass plate while supporting the glass ribbon at a portion below the scoring line by a supporting mechanism, and in the breaking process, the breaking rod is pressed against the scoring line formation area of ​​the glass ribbon (hereinafter referred to as the scoring line formation area).

[0028] In this way, the glass ribbon can be easily cut in the width direction. It should be noted that in the cutting step, the glass ribbon can also be cut by laser cutting, laser melting, etc., but the setting of the cutting conditions tends to be more complicated than the above-mentioned structure.

[0029] (10) In the structure of (9) above, it is preferred that the breaking process is the following process: while the breaking rod is pressed against the scoring line forming area, the supporting mechanism is operated, and the breaking rod is used as a fulcrum to bend the scoring line forming area in the longitudinal direction, thereby breaking the glass ribbon. When the glass ribbon is cut with an extended cutting length, the operating speed of the supporting mechanism for bending the scoring line forming area is set to a lower speed than when the glass ribbon is cut with a standard cutting length.

[0030] When the glass ribbon is cut with an extended cutting length, the glass ribbon may be broken. Therefore, from the viewpoint of suppressing longitudinal cracking of the glass ribbon, it is preferable to set the operating speed of the support mechanism to a lower speed than usual as in the above-mentioned configuration to safely cut the glass ribbon.

[0031] (11) In the structure of (9) above, it is preferred that the breaking process is a process in which the breaking rod is pressed against the score line forming area while the supporting mechanism is operated to bend the score line forming area in the longitudinal direction, thereby breaking the glass ribbon; and when the glass ribbon is cut with an extended cutting length, at least one of the operating speed of the supporting mechanism for bending the score line forming area and the operating speed of the breaking rod for pressing against the score line forming area is set to a lower speed than when the glass ribbon is cut with a standard cutting length.

[0032] When the glass ribbon is cut with an extended cutting length, the glass ribbon may be broken. Therefore, from the viewpoint of suppressing longitudinal cracking of the glass ribbon, it is preferable to set at least one of the operating speed of the support mechanism and the operating speed of the breaking rod to a lower speed than normal as in the above-mentioned structure, so as to safely cut the glass ribbon.

[0033] (12) In any one of the above-mentioned structures (9) to (11), it is preferred that, in the cutting process, when the glass ribbon is broken, the extended cutting length is set so that the broken portion of the glass ribbon is arranged at a position lower than the contact position of the supporting mechanism with respect to the glass ribbon.

[0034] In this manner, it is possible to reliably suppress the occurrence of a vertical crack in the glass ribbon due to the contact between the supporting mechanism and the damaged portion of the glass ribbon.

[0035] (13) The present invention made in order to solve the above-mentioned problems is a glass plate manufacturing device, which is provided with a cutting device for cutting a glass ribbon moving downward in a longitudinal posture along the width direction of the glass ribbon at a standard cutting length to obtain a glass plate, and the glass plate manufacturing device is characterized in that the glass plate manufacturing device is provided with: a judgment unit, which uses at least one of the lower end portion of the glass ribbon and the upper end portion of the glass plate after being cut by the cutting device as a judgment object and judges whether the judgment object is damaged; and a control unit, which adjusts the cutting length of the glass ribbon based on the judgment result of the judgment unit, and when the judgment unit determines that the judgment object is damaged, the control unit sets the cutting length of the glass ribbon to be cut by the cutting device next time to an extended cutting length longer than the standard cutting length.

[0036] In this way, the same operational effects as those of the corresponding structures already described can be achieved.

[0037] Effects of the Invention

[0038] According to the present invention, when a glass sheet is cut out from a glass ribbon, it is possible to reliably suppress the occurrence of vertical cracks in the glass ribbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1This is a schematic side view showing the entire structure of the glass plate manufacturing apparatus according to the first embodiment of the present invention.

[0040] Figure 2 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0041] Figure 3 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0042] Figure 4 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0043] Figure 5 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0044] Figure 6 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0045] Figure 7 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0046] Figure 8 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0047] Figure 9 This is a schematic front view showing an implementation of the method for manufacturing a glass plate according to the first embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0048] Figure 10 This is a schematic front view showing the main parts of a glass plate manufacturing apparatus according to a third embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0049] Figure 11 This is a schematic front view showing the main parts of a glass plate manufacturing apparatus according to a fourth embodiment of the present invention (from Figure 1(Figure when viewed from the A direction).

[0050] Figure 12 This is a schematic front view showing the main parts of a glass plate manufacturing apparatus according to a fifth embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0051] Figure 13 This is a schematic front view showing an implementation of a method for manufacturing a glass plate according to a fifth embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0052] Figure 14 This is a schematic front view showing an implementation of a method for manufacturing a glass plate according to a fifth embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0053] Figure 15 This is a schematic front view showing an implementation of a method for manufacturing a glass plate according to a fifth embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0054] Figure 16 This is a schematic front view showing an implementation of a method for manufacturing a glass plate according to a fifth embodiment of the present invention (from Figure 1 (Figure when viewed from the A direction).

[0055] Figure 17 This is a schematic front view (from the left) showing the main part of a modified example of the manufacturing apparatus of the glass plate according to the fifth embodiment of the present invention. Figure 1 (Figure when viewed from the A direction). DETAILED DESCRIPTION

[0056] The following describes a method and apparatus for manufacturing a glass sheet according to embodiments of the present invention with reference to the accompanying drawings. It should be noted that corresponding components in each embodiment are denoted by the same reference numerals, thereby omitting duplicate descriptions. While only a portion of a structure is described in each embodiment, the structure of the previously described other embodiments can be applied to the remaining portions of that structure. Furthermore, not only the combinations of structures explicitly described in the description of each embodiment are permitted, but also structures from multiple embodiments may be partially combined, even without explicit instruction, as long as there are no particular obstacles to the combination.

[0057] (First embodiment)

[0058] like Figure 1As shown, the glass sheet manufacturing apparatus of the first embodiment of the present invention includes a processing device 1 for a glass ribbon G, a cutting device 2, and a determination device 3. In this embodiment, the glass ribbon G is configured to move downward in a vertical posture (preferably a vertical posture) from the processing device 1 to the cutting device 2.

[0059] The processing device 1 includes: a forming zone 11, which continuously forms the glass ribbon G; a heat treatment zone 12, which heat treats (anneals) the glass ribbon G; a cooling zone 13, which cools the glass ribbon G to near room temperature; and a conveying device 14, which is composed of roller pairs R arranged in multiple levels above and below the forming zone 11, the heat treatment zone 12 and the cooling zone 13.

[0060] The forming zone 11 and the heat treatment zone 12 are formed by a furnace surrounded by a wall around the conveyance path of the glass ribbon G. Heating devices such as heaters for adjusting the temperature of the glass ribbon G are arranged at appropriate locations within the furnace. On the other hand, the cooling zone 13 is not surrounded by a wall around the conveyance path of the glass ribbon G but is open to the ambient temperature outside air and is not equipped with a heater or other heating device.

[0061] A forming body 15 is disposed within the interior of the forming area 11. Molten glass Gm is formed from molten glass Gm using an overflow downdraw method. Molten glass Gm supplied to the forming body 15 overflows from a groove (not shown) formed in the top 15a of the forming body 15. The overflowing molten glass Gm flows along the two side surfaces 15b of the wedge-shaped cross section of the forming body 15 and merges at the lower end. This continuously forms a sheet of glass ribbon G.

[0062] The interior of the heat treatment zone 12 has a predetermined temperature gradient downward. The vertically positioned glass ribbon G is heat-treated (annealed) so that its temperature decreases as it moves downward within the interior of the heat treatment zone 12. This heat treatment reduces the internal strain of the glass ribbon G. The temperature gradient within the heat treatment zone 12 is adjusted, for example, by a heating device provided on the inner surface of the wall of the heat treatment zone 12.

[0063] The multiple roller pairs R constituting the conveying device 14 clamp the widthwise ends of the longitudinally positioned glass ribbon G from both sides. The roller pairs R located at the top of the forming zone 11 are cooling rollers, sometimes also referred to as edge rollers. It should be noted that within the interior space of the heat treatment zone 12, the multiple roller pairs R may not include roller pairs clamping the side ends of the glass ribbon G. In other words, the spacing between the roller pairs R may be greater than the thickness of the widthwise ends of the glass ribbon G, allowing the glass ribbon G to pass between the roller pairs R.

[0064] In this embodiment, both widthwise end portions of the glass ribbon G manufactured by the processing apparatus 1 have portions (hereinafter referred to as ear portions) thicker than the widthwise central portion due to shrinkage during the forming process.

[0065] The cutting device 2 is configured to cut the vertical glass ribbon G into a predetermined length (standard cutting length L0) along the width direction below the processing device 1, thereby sequentially cutting out glass sheets g from the glass ribbon G. Here, the width direction is a direction perpendicular to the longitudinal direction (conveying direction) of the glass ribbon G and is substantially aligned with the horizontal direction in the present embodiment.

[0066] The cutting device 2 includes a scoring device 21 and a breaking device 22. The scoring device 21 and the breaking device 22 are configured to perform cutting-related operations while moving downward at the same speed as the glass ribbon G.

[0067] The scoring device 21 includes a cutter wheel 23 which cuts the first main surface of the glass ribbon G moving downward along the width direction (in the scoring position P1). Figure 1 and a support rod 24, which supports the glass ribbon G from the second main surface side of the cutter wheel 23 travels and is longer in the width direction.

[0068] The cutter wheel 23 has a cutting edge (edge) on its circumference that rotates when traveling, and is formed in a disk shape.

[0069] The support rods 24 have contact surfaces that abut against the portion where the cutter wheel 23 travels. The contact surfaces of the support rods 24 extend from both ends in the width direction of the glass ribbon G. The cutter wheel 23 and the support rods 24 are configured to form score lines S across the entire width direction of the glass ribbon G or a portion thereof as they move downward along with the glass ribbon G. In this embodiment, score lines S are also formed on the ears.

[0070] The breaking device 22 is a device that breaks the downwardly moving glass ribbon G along the score line S at a breaking position P2 located below the scoring position P1, thereby cutting the region of the glass ribbon G below the score line S (the lower region of the glass ribbon G) as a glass sheet g. In this embodiment, the breaking device 22 includes a breaking rod 25 that contacts the score line forming region Sx from the second main surface, and a support mechanism 26 that supports the glass ribbon G below the breaking position P2. It should be noted that in this embodiment, in order to perform the cutting operation while the glass ribbon G is moving downward, strictly speaking, the scoring position P1 and the breaking position P2 constitute regions having a width in the vertical direction.

[0071] The breaking rod 25 has a contact surface with a convex longitudinal cross-section (e.g., a semicircular or curved shape) that contacts the second main surface of the score line forming region Sx. The contact surface of the breaking rod 25 extends from both ends in the width direction of the glass ribbon G. Here, the score line forming region Sx refers to the region including the score line S, for example, the region between portions of the glass ribbon G separated by 80 to 120 mm in the upper and lower directions from the score line S.

[0072] The supporting mechanism 26 includes a plurality of chucks 27 for gripping both end portions in the width direction of the glass ribbon G and arms 28 for holding the plurality of chucks 27 (see FIG. Figure 2 ).

[0073] The supporting mechanism 26 is configured to support the glass ribbon G and change its posture from Figure 1 The basic posture shown by the dotted line changes to the structure of the tilted posture shown by the solid line in the figure. The posture change of the support mechanism 26 is achieved by breaking the position of the rod 25 ( Figure 1 The rotation movement of the support mechanism 4 (shown as the solid line position) as the center Figure 1 The support mechanism 26 is rotated in the direction B (direction B). Furthermore, the posture of the support mechanism 26 changes while the support mechanism 26 moves downward at the same speed as the glass ribbon G. Furthermore, the support mechanism 26, through the aforementioned rotational movement, bends the scored line forming region Sx so that the first main surface side becomes convex in the longitudinal direction. This rotational movement of the support mechanism 26 cooperates with the movement of the breaking rod 25 against the scored line forming region Sx to break the glass ribbon G along the scored line S.

[0074] The above-mentioned cutter wheel 23, support rod 24, breaking rod 25 and support mechanism 26 are configured to move downward at the same speed as the glass ribbon G while performing their own functions. In addition, the cutter wheel 23, support rod 24 and breaking rod 25 are configured to move along the thickness direction of the glass ribbon G between a working position for performing their own functions and a retreat position for separating from the glass ribbon G and retreating. The movement of these components along the thickness direction is performed while the glass ribbon G moves downward at the same speed as the glass ribbon G. It should be noted that, with respect to the breaking rod 25, Figure 1 The position shown by the solid line is the working position, and the position shown by the dotted line in the figure is the retreat position. On the other hand, for the cutter wheel 23 and the support rod 24, Figure 1 The position shown by the mid-dotted line is the operating position, and the position shown by the solid line in the figure is the retreat position.

[0075] like Figure 4 、 Figure 5 、 Figure 8 as well as Figure 9As shown, the determination device 3 is a device for determining whether or not damage occurs in the determination objects Gt and gt, using the lower end Gt of the glass ribbon G and the upper end gt of the glass sheet g (standard glass sheet gx or extended glass sheet gy) cut by the cutting device 2. It should be noted that the determination object may be only one of the lower end Gt of the glass ribbon G and the upper end gt of the glass sheet g. The reason why only the upper end gt of the glass sheet g can be used as the determination object is that: Figure 5 As shown, when a crack D1 is present at the lower end portion Gt of the glass ribbon G, a crack D2 is often also present at a corresponding position in the upper end portion gt of the glass sheet g. Therefore, the presence or absence of the crack D1 at the lower end portion Gt of the glass ribbon G can be predicted based on the presence or absence of the crack D2 at the upper end portion gt of the glass sheet g. The determination target may also include a portion of the glass ribbon G above the lower end portion Gt and / or a portion of the glass sheet g below the upper end portion gt.

[0076] In this embodiment, the determination device 3 includes a sensor 31 , a determination unit 32 , and a control unit 33 .

[0077] The sensor 31 is comprised of a thermal imager that measures the temperature distribution of the evaluation targets Gt and gt. It is located below the height of the cutter wheel 23 and above the lower end of the support mechanism 26. The sensor 31 of this embodiment is located below the height of the breaking rod 25 and above the lower end of the support mechanism 26, and measures the temperature distribution across the entire width of the evaluation targets Gt and gt. Furthermore, the sensor 31 is located at a position separated from the main surface of one of the evaluation targets Gt and gt (the first main surface of the glass ribbon G) at the center of the width of the evaluation targets Gt and gt. The separation distance between the sensor 31 and the evaluation targets Gt and gt can be arbitrarily set within a range capable of non-contact measurement of the temperature distribution of the evaluation targets Gt and gt (e.g., within a range of 800 to 3000 mm). Note that the sensor 31 may also be located on the other main surface of the evaluation targets Gt and gt.

[0078] Determination unit 32 analyzes the thermal image representing the temperature distribution obtained by sensor 31 and, based on the analysis, determines the presence or absence of damage in the determination targets Gt and gt. Because the temperature differs between areas where glass exists and areas where glass is absent due to damage, using a thermal imager as sensor 31 allows determination of the presence or absence of damage based on the temperature distribution. Determination unit 32 is comprised of, for example, an information processing device such as a personal computer.

[0079] Here, when the glass ribbon G is cut by breaking, not only the cut glass ribbon G may sway, but the glass sheet g may also sway due to vibration or swaying of the support mechanism 26. Furthermore, if the glass ribbon G is thin or warped, the swaying of the cut glass ribbon G and the glass sheet g may become noticeable. However, since the determination unit 32 determines the presence or absence of damage in the determination targets Gt and gt based on the temperature distribution obtained by the sensor 31, it is less susceptible to negative effects from the swaying of the glass ribbon G and the glass sheet g.

[0080] The control unit 33 adjusts the cut length of the glass ribbon based on the determination result of the determination unit 32. Specifically, when the determination unit 32 determines that the determination target Gt, gt is not broken, the control unit 33 adjusts the cut length of the glass ribbon based on the determination result of the determination unit 32. Figures 2 to 4 As shown in FIG, the cutting length of the glass ribbon G to be cut next time by the cutting device 2 is set to the standard cutting length L0. On the other hand, when the determination unit 32 determines that the determination target Gt, gt is broken, the control unit 33 Figures 6 to 8 As shown, the cutting length of the glass ribbon G to be cut next by the cutting device 2 is set to an extended cutting length L1, which is longer than the standard cutting length L0. The control unit 33 issues control signals corresponding to the respective cutting lengths L0 and L1 to the cutter wheel 23, support rod 24, breaking rod 25, support mechanism 26, etc., in order to execute cutting at the standard cutting length L0 or the extended cutting length L1. It should be noted that the cutting lengths L0 and L1 are managed based on the downward movement distance and / or movement time of the glass ribbon G.

[0081] Next, a method for producing a glass plate using the production apparatus configured as described above will be described.

[0082] like Figure 1 As shown, the method for manufacturing a glass sheet according to this embodiment includes a forming step, a conveying step, and a judging step. The conveying step includes a heat treatment step, a cooling step, and a cutting step.

[0083] The forming step is a step of forming the glass ribbon G by the overflow down-draw method in the forming zone 11. In the forming step, the glass ribbon G may be formed by other down-draw methods such as the redraw method and the slot down-draw method.

[0084] Here, the width direction length of the glass ribbon G and the glass plate g is 1000 to 3500 mm, and the thickness is 100 to 2000 μm. The standard cutting length L0 of the glass ribbon G is 800 to 3000 mm. The extended cutting length L1 is longer than the standard cutting length L0, and the difference (L1-L0) is preferably 0.05 m or more and 4.0 m or less, and more preferably 0.5 m or more and 1.5 m or less. In addition, the ratio (L1 / L0) of the extended cutting length L1 to the standard cutting length L0 is preferably 1.02 or more and 4.1 or less, and more preferably 1.05 or more and 2.0 or less. Here, as Figure 2 as well as Figure 6 As shown, the standard cutting length L0 and the extended cutting length L1 are respectively the lengths from the position (upper end) of the score line S formed in the current (nth) cutting process to the position (lower end) of the score line S formed in the previous (n-1th) cutting process. Therefore, when the glass ribbon G is broken, the position of the score line S, which serves as the reference for the cutting length, is a hypothetical position where no glass exists.

[0085] The conveying step is a step of conveying the glass ribbon G formed by the roller pair R (conveying device) downward.

[0086] The heat treatment step is a step of heat-treating (annealing) the glass ribbon G while conveying the glass ribbon G that has undergone the forming step in the heat treatment zone 12 .

[0087] The cooling step is a step of cooling the glass ribbon G while conveying the glass ribbon G that has undergone the heat treatment step in the cooling zone 13 .

[0088] The cutting step is a step of cutting the glass ribbon G in the width direction by the cutting device 2 while conveying the glass ribbon G that has undergone the cooling step, and cutting out the glass ribbon G as a glass sheet g.

[0089] The cutting process includes: a scoring process, in which a scoring line S is formed on the glass ribbon G along the width direction of the glass ribbon; and a breaking process, in which the glass ribbon G is broken along the scoring line S while the glass ribbon G is supported at a position below the scoring line S by the clamp 27 of the support mechanism 26 to cut out a glass plate g (standard glass plate gx or extended glass plate gy).

[0090] In the scribing process, first, the cutter wheel 23 and the support rod 24 are moved from the retreat position to the operating position while the glass ribbon G is supported by the plurality of chucks 27 of the support mechanism 26. Figure 2 or Figure 6 As shown, the cutter wheel 23 moved to the working position is moved along the width direction on the first main surface of the glass ribbon G to form the scored line S.

[0091] After the scoring process is completed, the cutter wheel 23 and the support rod 24 are moved from the working position to the retreat position. In this case, the support of the glass ribbon G by the clamp 27 of the support mechanism 26 continues even after the scoring process is completed. Here, at the moment when the scoring process is completed, the cutter wheel 23 and the support rod 24 are at the same height position as the scoring line S. Thereafter, as the glass ribbon G further moves downward, Figure 3 or Figure 7 As shown, a breaking rod 25 is held at the same height as the score line S instead of the cutter wheel 23 and the support rod 24 .

[0092] In the breaking process, Figure 1 As shown, while the breaking rod 25 is moved from the retreat position to the working position, the support mechanism 26 is rotated as shown by the arrow B. That is, in the breaking process, while the breaking rod 25 is pressed against the first main surface of the scoring line forming area Sx, the support mechanism 26 is rotated, and the scoring line forming area Sx is bent in a manner that the first main surface side becomes convex in the longitudinal direction using the breaking rod 25 as a fulcrum. As a result, as shown in FIG. Figure 4 or Figure 8 As shown, the glass ribbon G is broken along the score line S to cut out a glass sheet g.

[0093] The determination step involves analyzing the thermal image obtained by the sensor 31, which shows the temperature distribution, and determining the presence of damage in the determination targets Gt and gt based on the analysis results. It should be noted that in this embodiment, if damage is determined to be present in the determination targets Gt and gt during the determination step, detailed information such as the location, shape, and size of the damage is also determined based on the thermal image. In this embodiment, the determination step is automatically performed by the determination unit 32.

[0094] One method for determining the size of a crack is to determine the area of ​​a high-temperature region exceeding a predetermined temperature in an image obtained by a thermal imager. In this case, for example, if the area of ​​the high-temperature region falls below a predetermined threshold, it can be determined that the glass has a large crack. This is because the area where the glass is present is hot, while the area where the glass is absent due to the crack is cold.

[0095] In the determination process, if the determination unit 32 determines that the determination target Gt, gt does not have any breakage, the control unit 33 sets the cutting length of the glass ribbon G in the next cutting process to the standard cutting length L0, and sends a control signal corresponding to the standard cutting length L0 to the cutter wheel 23, the support rod 24, the breaking rod 25, the support mechanism 26, etc. Figures 2 to 4As shown, in the next cutting step, the glass ribbon G is broken in the width direction at the standard cutting length L0, and a standard glass plate gx cut at the standard cutting length L0 is obtained as the glass plate g. Figure 2 As shown, at the scoring position P1, at a position corresponding to the standard cutting length L0, the cutter wheel 23 and the support rod 24 form a scoring line S along the width direction on the first main surface of the glass ribbon G. Figure 3 as well as Figure 4 As shown, at the breaking position P2, the glass ribbon G is broken along the width direction at the standard cutting length L0 by the breaking rod 25 and the supporting mechanism 26, thereby cutting out a standard glass sheet gx. The cut standard glass sheet gx becomes the original glass sheet (mother glass sheet) from which one or more product glass sheets are extracted. Specifically, if the cut standard glass sheet gx is intact, it is transported to subsequent processes including the ear cutting process, the cleaning process, the inspection process, and the packaging process.

[0096] On the other hand, Figure 5 As shown, in the determination process, when the determination unit 32 determines that the determination objects Gt and gt have damage D1 and D2, the control unit 33 sets the cutting length of the glass ribbon G in the next cutting process to the extended cutting length L1, and sends a control signal corresponding to the extended cutting length L1 to the cutter wheel 23, the support rod 24, the breaking rod 25, the support mechanism 26, etc. Figures 6 to 8 As shown, in the next cutting step, the glass ribbon G is broken in the width direction by the extended cutting length L1, and the extended glass sheet gy cut by the extended cutting length L1 is obtained as the glass sheet g. Figure 6 As shown, at the scoring position P1, at a position corresponding to the extended cutting length L1, the cutter wheel 23 and the support rod 24 form a scoring line S along the width direction on the first main surface of the glass ribbon G. Figure 7 as well as Figure 8 As shown, at the breaking position P2, the glass ribbon G is broken along the width direction by the extended cutting length L1 by the breaking rod 25 and the support mechanism 26, thereby cutting out an extended glass sheet gy. The cut extended glass sheet gy is discarded as a defective product. It should be noted that if the determination unit 32 determines that the determination targets Gt and gt have damage D1 and D2, the glass sheet g including the determination target gt is also discarded. In other words, if the determination unit 32 determines that the determination targets Gt and gt have damage D1 and D2, at least two glass sheets g are discarded consecutively. For example, the glass sheets g are discarded by releasing the support provided by the chuck 27 of the support mechanism 26, causing them to fall into a collection chamber located below the cutting chamber.

[0097] Here, as Figure 9As shown, after the glass ribbon G is cut with the extended cutting length L1, if it is again determined in the determination step that the determination targets Gt and gt have damage D3 and D4, the glass ribbon G is cut with the extended cutting length L1 in the subsequent cutting step. On the other hand, after the glass ribbon G is cut with the extended cutting length L1, if it is determined in the determination step that the determination targets Gt and gt do not have damage, the glass ribbon G is cut with the standard cutting length L0 in the subsequent cutting step. Thereafter, based on the result of the determination step, the cutting length of the glass ribbon G is adjusted to either the standard cutting length L0 or the extended cutting length L1, and the same operation is repeated.

[0098] According to the above configuration, when the determination targets Gt and gt are damaged, the glass ribbon G is cut using an extended cutting length L1 that is longer than the standard cutting length L0. Therefore, the damaged portion of the glass ribbon G can be sufficiently separated downward from the cut position (scored line forming region Sx) of the glass ribbon G. Consequently, the occurrence of longitudinal cracks in the glass ribbon G that extend beyond the cut position of the glass ribbon G can be reliably suppressed.

[0099] The extended cutting length L1 is preferably set so that the portion of the glass ribbon G where the crack D1 is located is positioned below the position where the lowest chuck 27 of the support mechanism 26 contacts the glass ribbon G. Thus, the occurrence of longitudinal cracks in the glass ribbon G due to contact between the portion of the glass ribbon G where the crack D1 is located and the chuck 27 can be reliably suppressed.

[0100] While the extended cutting length L1 is a predetermined fixed value in this embodiment, it can also be a variable value that changes based on the size (vertical length or area on the thermal image, etc.) of the defects D1 and D2 of the determination targets Gt and gt. Specifically, if the defects D1 and D2 are larger as determined by the determination unit 32, the extended cutting length L1 can be increased, while if the defects D1 and D2 are smaller, the extended cutting length L1 can be decreased. In this way, the length of the extended glass sheet gy can be set to the optimal length corresponding to the defect size, thereby reducing glass waste.

[0101] In the scribing process, it is preferred that Figure 2 As shown in FIG, the travel speed V0 of the cutter wheel 23 when the glass ribbon G is cut with the standard cutting length L0 is compared. Figure 6 As shown in FIG, the travel speed V1 of the cutter wheel 23 when the glass ribbon G is cut with the extended cutting length L1 is set to a low speed. Figure 4 When the glass ribbon G is cut with the standard cutting length L0 as shown in FIG. 1 , the operating speed W0 of the support mechanism 26 for bending the scored line forming region Sx is compared with the operating speed W0 of the support mechanism 26 for bending the scored line forming region Sx. Figure 8The operating speed of the support mechanism 26 for bending the scored line forming region Sx when the glass ribbon G is cut with the extended cutting length L1 as shown in FIG. Figure 1 The operating speed W1 in the B direction is set to a low speed. Thereby, the glass ribbon G having a crack can be cut more safely by extending the cutting length L1, so that the longitudinal cracking of the glass ribbon G can be suppressed more reliably.

[0102] (Second embodiment)

[0103] The glass sheet manufacturing apparatus and method according to the second embodiment of the present invention differ from the first embodiment in the breaking step for breaking the glass ribbon G. In the breaking step of the first embodiment, the following is described: while the breaking rod 25 is pressed against the score-line forming region Sx, the support mechanism 26 is rotated, and the score-line forming region Sx is bent longitudinally using the breaking rod 25 as a fulcrum, thereby breaking the glass ribbon. In contrast, in the breaking step of the second embodiment, while the support mechanism 26 is operated to longitudinally bend the score-line forming region Sx, the breaking rod 25 is pressed against the score-line forming region Sx, thereby breaking the glass ribbon. In other words, the timing of pressing the breaking rod 25 and rotating the support mechanism 26 differs from the first embodiment.

[0104] This breaking process allows the glass ribbon G to be properly broken even if it warps in the longitudinal direction (longitudinal direction) or in the orthogonal width direction while moving downward in a vertical position. This warping can minimize the negative effects of the warping and minimize damage to the lower end of the glass ribbon G caused by cutting. Specifically, in this method, in the breaking process following the scoring process, the scored line forming region Sx of the glass ribbon G is first bent in the longitudinal direction. This forced bending deformation in this region Sx naturally eliminates the warp. Next, the breaking rod 25 is pressed against the bent scored line forming region Sx, which has eliminated the warp. This ensures uniform, non-partial contact between the breaking rod 25 and the region Sx. Furthermore, since the glass ribbon G is broken while maintaining uniform contact with the breaking rod 25, erroneous cutting is less likely to occur. Furthermore, since the need to account for erroneous cutting during breaking is reduced, the support mechanism 26 can be operated at high speed, shortening production cycle time.

[0105] In this case, in the breaking step, when the glass ribbon G is cut with the extended cutting length L1, it is preferable that the operating speed of the support mechanism 26 for bending the scored line forming area Sx and the operating speed of the breaking rod 25 for pressing against the scored line forming area Sx are increased ( Figure 1At least one of the speed of movement of the breaking rod 25 from the retreat position to the operating position is set to a low speed. As a result, the broken glass ribbon G can be cut more safely with the extended cutting length L1, thereby more reliably suppressing longitudinal cracking of the glass ribbon G.

[0106] When the operating speed of the support mechanism 26 when cutting with the extended cutting length L1 is X1 and the operating speed of the support mechanism 26 when cutting with the standard cutting length L0 is X0, X1 / X0 is preferably 10% to 90%. In addition, when the operating speed of the breaking rod 25 when cutting with the extended cutting length L1 is Y1 and the operating speed of the breaking rod 25 when cutting with the standard cutting length L0 is Y0, Y1 / Y0 is preferably 10% to 90%.

[0107] (Third embodiment)

[0108] like Figure 10 As shown, the glass sheet manufacturing apparatus and glass sheet manufacturing method of the third embodiment differ from the aforementioned embodiments in that multiple (three in the example) sensors (thermal imagers) 31 are provided along the width direction. This allows for more detailed measurement of the entire width of the determination targets Gt and gt, compared to using a single sensor 31 to measure the entire width of the determination targets Gt and gt. Consequently, during the determination process, the determination unit 32 can more accurately determine the presence or absence of damage in the width direction of the determination targets Gt and gt. When multiple sensors 31 are provided, it is preferable to provide a dedicated sensor 31 for each of at least three regions of the determination targets Gt and gt: one widthwise end, the center, and the other widthwise end.

[0109] (Fourth embodiment)

[0110] like Figure 11 As shown, the glass plate manufacturing apparatus and glass plate manufacturing method according to the fourth embodiment of the present invention are different from the above-mentioned embodiments in that in the determination step, the sensor 31 is used to measure only the width direction end edge (ear) of the determination object (the lower end portion of the glass ribbon G) Gt.

[0111] In this embodiment, sensors 31 are provided on each arm 28 of the support mechanism 26. In the illustrated example, one sensor 31 is provided on each arm 28, between the lowest chuck 27 and the second-lowest chuck 27. With the chucks 27 of the support mechanism 26 open, the determination unit 32 measures the presence of both widthwise end edges of the determination target Gt as it moves downward while passing between the chucks 27. The control unit 33 issues control signals to the cutter wheel 23, support rod 24, breaking rod 25, support mechanism 26, and the like, such that the cutting operation begins a predetermined time after the determination unit 32 determines that both widthwise end edges of the determination target Gt are present. Specifically, if the widthwise end edges of the determination target Gt are damaged, the cut length of the glass ribbon G (the length from the position of the score line S formed in the nth cutting step (upper end) to the position of the score line S formed in the n-1th cutting step (lower end)) is increased compared to if the widthwise end edges of the determination target Gt are not damaged. Therefore, even in such a configuration, when it is determined in the determination step that the determination target Gt is broken, the glass ribbon G is cut at an extended cutting length longer than the standard cutting length in the next cutting step.

[0112] It should be noted that, in the case of the above-described configuration, even if there is a break in the widthwise central portion of the glass ribbon G, if there is no break at either end edge in the widthwise direction of the glass ribbon G, it is not determined that there is a break in the glass ribbon G. However, longitudinal breakage of the glass ribbon G is particularly likely to occur near the cutting position of the glass ribbon G when the glass ribbon G is cut without either end edge in the widthwise direction of the glass ribbon G. Therefore, even if only the presence or absence of breakage at either end edge in the widthwise direction of the glass ribbon G is determined, longitudinal breakage of the glass ribbon G is suppressed. It should be noted that, from the perspective of further suppressing longitudinal breakage, it is preferable to add a sensor for determining the presence or absence of the widthwise central portion of the glass ribbon G to the above-described configuration.

[0113] (Fifth embodiment)

[0114] like Figure 12 As shown, the glass plate manufacturing device and glass plate manufacturing method of the fifth embodiment of the present invention are different from the above embodiments in that multiple sensors 31 are arranged in the vertical direction, and in the judgment process, the objects of judgment are different according to the upper sensor 31a and the lower sensor 31b.

[0115] For example, Figure 13 as well as Figure 14As shown, the judgment area Ja of the upper sensor 31a (the area surrounded by the dotted line) includes the entire width direction area of ​​the upper end gt of the glass plate g as the judgment object, and the judgment area Jb of the lower sensor 31b (the area surrounded by the dotted line) includes the entire width direction area of ​​the central part gu below the upper end gt of the glass plate g as the judgment object.

[0116] If this structure is Figure 13 as well as Figure 14 As shown in FIG. 1 , when there are large cracks D5 and D6 extending from the upper end gt to the center gu of the glass plate g, not only the upper sensor 31a but also the lower sensor 31b will detect the glass breakage. When the lower sensor 31b detects the glass breakage, the extended cutting length L1 is set to the first length. On the other hand, if Figure 15 As shown in FIG, there is a case where a break D7 occurs only at the upper end gt of the glass sheet g, rather than a large break extending from the upper end gt to the central portion gu. In this case, the breakage of the glass is detected only by the upper sensor 31a. In this case, when the breakage of the glass is detected only by the upper sensor 31a, the extended cutting length L1 is set to a second length shorter than the first length. Figure 16 As shown, there may be cases where a breakage D8 occurs only in the central portion gu of the glass sheet g (in the example shown, at the widthwise end of the central portion gu). In this case, the glass breakage is detected only by the lower sensor 31b. Even when the glass breakage is detected only by the lower sensor 31b, there may be minor damage at the upper end gt of the glass sheet g. Therefore, it is preferable to set the extended cutting length L1 to the first length (> the second length).

[0117] For example, it is preferable that the vertical ranges of the determination area Ja of the upper sensor 31a and the determination area Jb of the lower sensor 31b are equal, or the vertical range of the determination area Ja of the upper sensor 31a is larger than the vertical range of the determination area Jb of the lower sensor 31b. The vertical ranges of the determination area Ja of the upper sensor 31a and the determination area Jb of the lower sensor 31b are each preferably 0.5 to 10%, more preferably 1 to 7%, of the standard cutting length L0 of the glass ribbon G.

[0118] like Figure 17As shown, the determination area Jb of the lower sensor 31b (area surrounded by a dotted line) may include the entire widthwise area of ​​the lower end Gt of the glass ribbon G as a determination target, and the determination area Ja of the upper sensor 31a (area surrounded by a dotted line) may include the entire widthwise area of ​​the central portion Gu above the lower end Gt of the glass ribbon G as a determination target. In this case, as in the above, it is possible to distinguish (1) the presence of a large crack extending from the lower end Gt of the glass ribbon G to the central portion Gu, (2) the presence of a crack only at the lower end Gt of the glass ribbon G, and (3) the presence of a crack only at the central portion Gu of the glass ribbon G, and adjust the length of the extended cutting length L1. For example, in the case of a large crack extending from the lower end Gt of the glass ribbon G to the central portion Gu and in the case of a crack only at the central portion Gu of the glass ribbon G, the extended cutting length L1 may be set to a relatively long first length, and in the case of a crack only at the lower end Gt of the glass ribbon G, the extended cutting length L1 may be set to a relatively short second length.

[0119] It should be noted that, in the present embodiment, the situation of adjusting the extended cut length L1 according to the damaged mode, specifically the vertical position of the damaged, is described, but the extended cut length L1 can also be adjusted according to the width position of the damaged (or the vertical position and the width position). For example, it is also possible to set the extended cut length L1 to be relatively long when the damaged position includes the width end portion, and to set the extended cut length L1 to be relatively short when the damaged position is only the width center portion. In addition, the damaged mode includes not only the location of the damaged, but also the size of the damaged, and the extended cut length L1 can be adjusted considering the size of the damaged. For example, it is possible to set the extended cut length L1 to be relatively long when the size of the damaged is large, and to set the extended cut length L1 to be relatively short when the size of the damaged is small. In addition, as the damaged mode, for example, the shape of the damaged part can be included, and the extended cut length L1 can be set according to the shape of the damaged part.

[0120] As mentioned above, the glass plate manufacturing apparatus and the manufacturing method thereof according to the embodiment of the present invention have been described, but the embodiment of the present invention is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

[0121] In the above embodiment, a thermal imager is used as the sensor 31 for measuring the determination target. However, the sensor 31 is not limited to this. For example, the sensor 31 may be another temperature sensor such as a radiation thermometer, or a laser sensor that irradiates laser light and detects transmitted or reflected light from the determination targets Gt and gt.

[0122] In the above embodiment, the breaking rod 25 is pressed against the glass ribbon G (scored line forming region Gx) at the same or approximately the same height as the score line S. However, the breaking rod 25 may also be pressed against a portion of the glass ribbon G above the score line S. Here, the portion above the score line S refers to a portion of the glass ribbon G that is not bent in the longitudinal direction and is separated upward from the score line S by a predetermined distance. This predetermined distance can be set to be greater than 5 mm and less than 70 mm. Furthermore, considering the existence of an effective region (the region that becomes a glass sheet after breaking) in the glass ribbon G, the predetermined distance may be set to be greater than 5 mm and less than the distance from the score line S to the bottom end of the effective region. In this case, the predetermined distance is set to be greater than 5 mm and less than 20 mm, taking into account the effective region of the glass ribbon G in this embodiment.

[0123] In the above embodiment, the support mechanism 4 is configured to move the position of the breaking rod 25 (at Figure 1 The support mechanism 4 may be configured to rotate along a circular orbit (shown by the solid line in the middle) as its center, but may also be configured to rotate along a curved orbit other than a circular orbit. Furthermore, the support mechanism 4 may be configured to be other than a rotational motion as long as it can bend the scribed line forming area Gx.

[0124] In the above embodiment, the support mechanism 4 is configured to clamp and support the glass ribbon G using the chuck 27. However, the support method of the support mechanism 4 is not limited thereto. For example, the support mechanism 4 may be configured to support the first or second main surface of the glass ribbon G by suction using a suction pad or the like.

[0125] In the above-described embodiment, the glass ribbon G is cut by breaking along the score lines S. However, the glass ribbon G may be cut by other methods such as laser cutting and laser melting.

[0126] Description of Reference Numerals

[0127] 1: Processing device, 2: Cutting device, 3: Determination device, 4: Support mechanism, 11: Forming zone, 12: Heat treatment zone, 13: Cooling zone, 14: Transport device, 15: Forming body, 21: Scoring device, 22: Breaking device, 23: Cutter wheel, 24: Support rod, 25: Breaking rod, 26: Support mechanism, 27: Chuck, 31: Sensor, 32: Determination unit, 33: Control unit, D1 to D8: Breakage, G: Glass ribbon, g: Glass sheet, Gt: Determination object (lower end of glass ribbon), gt: Determination object (upper end of glass sheet), Gx: Score line forming area, gx: Standard glass sheet, gy: Extended glass sheet, L0: Standard cutting length, L1: Extended cutting length, S: Score line, Sx: Score line forming area.

Claims

1. A method for producing a glass sheet, comprising the step of cutting a glass ribbon moving downward in a longitudinal position by cutting the glass ribbon along the width direction of the glass ribbon at a standard cutting length to obtain a glass sheet, The method for manufacturing the glass plate is characterized in that: The method for manufacturing a glass sheet includes a determination step of determining whether or not the determination target is damaged by taking at least one of a lower end portion of the glass ribbon and an upper end portion of the glass sheet after being cut in the cutting step as a determination target. When it is determined in the determination step that the breakage of the determination target exists, the glass ribbon is cut at an extended cutting length longer than the standard cutting length in the next cutting step.

2. The method for manufacturing a glass plate according to claim 1, wherein: In the determination step, the determination object is measured by a sensor, and the presence or absence of damage to the determination object is determined based on the measurement result of the sensor.

3. The method for manufacturing a glass plate according to claim 2, wherein: The sensor measures a widthwise end portion of the determination object.

4. The method for producing a glass plate according to claim 2 or 3, wherein: The sensor measures widthwise end portions and a widthwise center portion of the determination object.

5. The method for producing a glass plate according to any one of claims 1 to 3, wherein A value obtained by subtracting the standard cut length from the extended cut length is 0.05 m or more and 4.0 m or less.

6. The method for producing a glass plate according to any one of claims 1 to 3, wherein: The extended cutting length is not less than 1.02 times and not more than 4.1 times the standard cutting length.

7. The method for producing a glass plate according to any one of claims 1 to 3, wherein: In the cutting step, the length of the extended cutting length is adjusted according to the type of damage of the determination target.

8. The method for manufacturing a glass plate according to claim 7, wherein: In the cutting step, the length of the extended cutting length is adjusted according to at least one of the position and size of the damage to be determined.

9. The method for producing a glass plate according to any one of claims 1 to 3, wherein: The cutting step includes: a scoring step of forming a score line on the glass ribbon along the width direction of the glass ribbon; and a breaking step of breaking the glass ribbon along the score line while supporting the glass ribbon at a portion below the score line by a supporting mechanism to cut out the glass sheet. In the breaking step, a breaking rod is pressed against a region of the glass ribbon where the scored line is formed.

10. The method for manufacturing a glass plate according to claim 9, wherein: The breaking step is a step of operating the support mechanism while pressing the breaking rod against the scored line forming area, bending the scored line forming area in the longitudinal direction using the breaking rod as a fulcrum, thereby breaking the glass ribbon. When the glass ribbon is cut at the extended cutting length, the operating speed of the support mechanism for bending the scored line formation region is set to be lower than when the glass ribbon is cut at the standard cutting length.

11. The method for manufacturing a glass plate according to claim 9, wherein: The breaking step is a step of: operating the support mechanism to bend the scored line forming area in the longitudinal direction, pressing the breaking rod toward the scored line forming area to break the glass ribbon; When the glass ribbon is cut with the extended cutting length, at least one of the movement speed of the support mechanism that bends the area where the scored line is formed and the movement speed of the breaking rod that presses against the area where the scored line is formed is set to a lower speed than when the glass ribbon is cut with the standard cutting length.

12. The method for manufacturing a glass plate according to claim 9, wherein: In the cutting step, when the glass ribbon is broken, the extended cutting length is set so that the broken portion of the glass ribbon is arranged below a contact position of the supporting mechanism with respect to the glass ribbon.

13. A glass sheet manufacturing apparatus comprising a cutting device for cutting a glass ribbon moving downward in a longitudinal position along the width direction of the glass ribbon at a standard cutting length to obtain a glass sheet, The glass plate manufacturing device is characterized in that: The glass plate manufacturing device comprises: a determination unit that determines whether or not the determination target is damaged by taking a portion including at least one of a lower end portion of the glass ribbon and an upper end portion of the glass sheet cut by the cutting device as a determination target; and a control unit that adjusts the cut length of the glass ribbon based on the determination result of the determination unit, The control unit sets the cutting length of the glass ribbon to be cut next by the cutting device to an extended cutting length longer than the standard cutting length when the determination unit determines that the breakage of the determination target exists.

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