Manufacturing method of glass plate

Abstract

To appropriately execute an end surface processing step after abnormality of a glass plate is detected while suppressing breakage or the like of the glass plate in detecting the abnormality of the glass plate.SOLUTION: A manufacturing method of a glass plate includes an end surface processing step in which a first end surface Ga1 is processed by contacting a grindstone 12 with the first end surface Ga1 of a glass plate G extending in a relative movement direction while relatively moving the grindstone 12 and the glass plate G, and also includes: an abnormality detection step of detecting abnormality of the glass plate G by contacting a contactor 6 of an abnormality detection device 4, which relatively moves together with the grindstone 12 with respect to the glass plate G and can come in contact with the first end surface Ga1 of the glass plate G prior to the grindstone 12, with at least one of the first end surface Ga1 of the glass plate G and a second end surface Gb2 orthogonal to the first end surface Ga1; and a cancelling step of cancelling the end surface processing step when the abnormality of the glass plate G is detected in the abnormality detection step.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a glass sheet, and more particularly to a method for manufacturing a glass sheet including an edge processing step. [Background technology]

[0002] In the manufacturing process of glass substrates used for liquid crystal displays and the like, one or more glass plates are cut out from a large glass original plate (formed original plate). The edge faces of the cut glass plates are usually subjected to grinding (rough processing) and polishing (finishing processing). When carrying out such an edge processing process of the glass plate, there are cases where an abnormality occurs in the glass plate.

[0003] One example of a measure against an abnormality in a glass plate is disclosed in Patent Document 1. In this document, abnormal irregularities occurring on an end face of a glass plate are considered to be an abnormality in the glass plate. This document also discloses that when a processing tool (e.g., a grinding wheel) is pressed against the end face of the glass plate to perform an end face processing step, the processing tool is made to detect the abnormal irregularities, and at the point in time when the processing tool detects the abnormal irregularities, the processing tool is moved away from the end face of the glass plate.

[0004] Another example is a measure disclosed in Patent Document 2. In this document, a positional deviation of an end face of a glass plate is regarded as an abnormality of the glass plate. This document also discloses that a contactor that can contact the end face of the glass plate before a processing tool (grindstone) detects the positional deviation of the end face of the glass plate, adjusts the position of the processing tool according to the detected positional deviation, and then executes an end face processing step using the processing tool. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6978724 [Patent Document 2] Patent No. 7108240 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the countermeasures disclosed in Patent Document 1, an abnormality in the glass plate is detected when a processing tool that is strongly pressed against an edge face of the glass plate reaches an abnormal unevenness occurring on the edge face. Therefore, at the time when the abnormality in the glass plate is detected, there is a risk that the glass plate will be damaged, such as cracked, starting from the unevenness.

[0007] On the other hand, as disclosed in Patent Document 2, the measure of performing the edge processing step by adjusting the position of the processing tool according to the positional deviation of the edge of the glass plate makes it difficult to perform high-precision edge processing because the adjustment of the position of the processing tool is likely to be misaligned. Moreover, when the positional deviation of the edge of the glass plate is large, there are cases where it is not possible to deal with it by adjusting the position of the processing tool.

[0008] From the above perspective, an object of the present invention is to be able to properly execute an edge processing process after detecting an abnormality in a glass plate, while preventing damage to the glass plate, etc., when detecting an abnormality in the glass plate. [Means for solving the problem]

[0009] (1) A first aspect of the present invention devised to solve the above-mentioned problems is a method for manufacturing a glass plate, comprising an edge processing step in which a processing tool and a glass plate are moved relative to each other while the processing tool is brought into contact with an end face of a first side of the glass plate extending in the direction of relative movement to process the end face, and the method is characterized by comprising an abnormality detection step in which a contactor of an abnormality detection device, which moves relative to the glass plate together with the processing tool and is configured to contact the end face of the first side of the glass plate before the processing tool does, is brought into contact with at least one of the end faces of the first side and the end face of a second side perpendicular to the end face of the first side of the glass plate to detect an abnormality in the glass plate, and an interruption step in which an abnormality in the glass plate is detected in the abnormality detection step.

[0010] According to this configuration, since the detection of an abnormality in the glass plate is performed by the contact of the abnormality detection device, it is not necessary to apply a strong pressing force to the glass plate as with a processing tool. Moreover, since the edge processing process is stopped when an abnormality in the glass plate is detected, when the edge processing process is performed again thereafter, a new edge processing process can be performed regardless of the abnormality in the glass plate. This makes it possible to properly perform the edge processing process after the abnormality in the glass plate is detected while preventing damage to the glass plate when the abnormality in the glass plate is detected.

[0011] (2) In the configuration of (1) above, the abnormality in the glass plate is a convex or concave portion that occurs partially on the end face of a first side of the glass plate, and an abnormality detection process is carried out during the end face processing process, and in the abnormality detection process, a case in which the contactor rides up on the convex portion or enters the concave portion may be determined to be an abnormality in the glass plate.

[0012] In this way, a protrusion or recess that occurs partially on the edge face of the glass sheet can be properly detected as an abnormality in the glass sheet.

[0013] (3) In the configuration of (2) above, in the stopping step, the processing tool is retracted to a position where it does not interfere with the glass plate, and after the stopping step is performed, the glass plate may be discarded or reused by removing the convex or concave portions.

[0014] In this way, as soon as the contact detects the presence of a convex or concave portion, the processing tool can be retracted to a position where it does not interfere with the glass plate, thereby quickly preventing unnecessary edge processing by the processing tool.

[0015] (4) In any one of the above configurations (1) to (3), the contact of the abnormality detection device may have a smaller contact pressure with respect to the end face of the first side of the glass plate than the processing tool.

[0016] This makes it possible to more reliably prevent damage to the glass plate when detecting an abnormality in the glass plate.

[0017] (5) In any of the configurations (1) to (4) above, the abnormality detection device may include a swingable arm member, the contactor is attached to a tip of the arm member and urged toward an end face of a first side of the glass plate, the glass plate is set in a fixed position, and the processing tool and the arm member may be held on a single movable base and moved together.

[0018] In this way, the end face processing step and the abnormality detection step can be smoothly performed by a compact device.

[0019] (6) In any of the configurations (1) to (5) above, the edge processing step is performed by bringing a pair of processing tools into contact with edge faces of a pair of first sides of the glass plate, and an abnormality detection step may be performed before the edge processing step is performed.

[0020] In this way, abnormalities in the posture or position of the glass plate can be detected.

[0021] (7) In the configuration of (6) above, the abnormality in the glass plate is an abnormality in the position of the glass plate in a direction along the first side, and in the abnormality detection process, a case in which a pair of contacts contact an end face of one of the second sides of the glass plate at the same position in the direction along the first side and that position is different from a normal position may be detected as an abnormality in the glass plate.

[0022] With this arrangement, in the abnormality detection step, an abnormality in the position of the glass plate with respect to the direction along the first side is appropriately detected as an abnormality in the glass plate.

[0023] (8) In the configuration of (7) above, in the interruption step, the relative movement between the pair of processing tools and the glass plate is interrupted, and after the interruption step is performed, the positional abnormality is corrected and an edge processing step is performed on the glass plate.

[0024] In this way, the stopping step is performed properly, and the subsequent edge processing step is also performed properly. In this case, if the stopping step is performed when an abnormality in the glass plate is detected in the abnormality detection step, that is, when the pair of contacts are in contact with the edge of the second side of the glass plate, the relative movement of the processing tool and the contacts can be stopped before the processing tool reaches the edge of the first side of the glass plate. This makes it possible to appropriately avoid a problem in which the edge of the first side of the glass plate is improperly processed by the processing tool.

[0025] (9) In the above configuration (6), the abnormality in the glass plate is an abnormality in the position of the glass plate in the direction along the second side, and in the abnormality detection process, when the pair of contacts are in contact with the end faces of a pair of first sides of the glass plate, the glass plate may be judged to be abnormal if any of the positions of the pair of contacts in the direction along the second side of the glass plate is different from the normal positions and the distance between the pair of contacts is the same as the normal distance.

[0026] With this arrangement, in the abnormality detection step, an abnormality in the position of the glass plate with respect to the direction along the second side is appropriately detected as an abnormality in the glass plate.

[0027] (10) In the configuration of (9) above, in the interruption step, the pair of processing tools may be retracted to a position where they do not interfere with the glass plate, and after the interruption step is performed, the positional abnormality may be corrected and the edge processing step may be performed on the glass plate.

[0028] In this way, the stopping step is properly performed, and the subsequent edge processing step is also properly performed. In this case, after an abnormality in the glass sheet is detected in the abnormality detection step, the stopping step can be performed to retract the processing tool before the processing tool reaches the edge of the first side of the glass sheet. This can appropriately avoid the problem of the processing tool improperly processing the edge of the first side of the glass sheet.

[0029] (11) In the above configuration (6), the abnormality in the glass plate is a deviation in the dimension of the glass plate in the direction along the second side, and in the abnormality detection process, a case in which the spacing between the pair of contacts is different from a normal spacing when the pair of contacts are in contact with end faces of a pair of first sides of the glass plate may be detected as an abnormality in the glass plate.

[0030] With this arrangement, in the anomaly detection step, a deviation in the dimension of the glass plate in the direction along the second side is appropriately detected as an anomaly of the glass plate.

[0031] (12) In the configuration of (11) above, in the stopping step, the pair of processing tools are retracted to a position where they do not interfere with the glass plate, and after the stopping step is performed, the glass plate may be discarded or the size of the glass plate may be adjusted and reused.

[0032] In this way, the interruption step is properly performed, and the subsequent edge processing step is also properly performed. In this case, as in the case of the above-mentioned (10), it is possible to properly avoid the problem of the edge of the first side of the glass sheet being improperly processed by the processing tool.

[0033] (13) In the configuration of (6) above, the abnormality of the glass plate is a misalignment of the glass plate such that the glass plate is in an inclined position. In the abnormality detection process, the glass plate may be abnormal when one contactor and the other contactor of a pair of contacts contact an end face of a second side of the glass plate at different positions in the direction along the first side, or when one contactor contacts an end face of a second side of the glass plate and the other contactor contacts an end face of the first side of the glass plate.

[0034] In this way, any deviation in the orientation of the glass plate that results in the glass plate being in an inclined orientation is appropriately detected as an abnormality in the glass plate in the abnormality detection step.

[0035] (14) In the configuration of (13) above, in the interruption step, the relative movement between the pair of processing tools and the glass plate is interrupted, and after the interruption step is performed, the misalignment of the glass plate is corrected and an end face processing step is performed on the glass plate.

[0036] In this way, the stopping step is properly performed, and the subsequent edge processing step is also properly performed. In this case, if the stopping step is performed when an abnormality in the glass sheet is detected in the abnormality detection step, that is, when at least one of the pair of contacts is in contact with the edge of the second side of the glass sheet, the relative movement of the processing tool and the contacts can be stopped before the processing tool reaches the edge of the first side. This makes it possible to properly avoid a problem in which the edge of the first side of the glass sheet is improperly processed by the processing tool. Effect of the Invention

[0037] According to the present invention, it is possible to properly execute an edge processing step after detecting an abnormality in a glass plate, while preventing damage to the glass plate when detecting an abnormality in the glass plate. [Brief description of the drawings]

[0038] [Figure 1] 1 is a plan view showing an overall configuration of a glass sheet manufacturing apparatus used to carry out a glass sheet manufacturing method according to an embodiment of the present invention. [Diagram 2] 1 is a plan view showing a configuration of a main part of a glass sheet manufacturing apparatus used to carry out a glass sheet manufacturing method according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view showing the operation of a main part of a glass sheet manufacturing apparatus used to carry out a glass sheet manufacturing method according to an embodiment of the present invention. [Figure 4] 1 is a plan view showing a configuration of a main part of a glass sheet manufacturing apparatus used to carry out a glass sheet manufacturing method according to an embodiment of the present invention. [Diagram 5] 1 is a plan view showing a configuration of a main part of a glass sheet manufacturing apparatus used to carry out a glass sheet manufacturing method according to an embodiment of the present invention. [Figure 6] FIG. 1 is a schematic plan view showing a state in which a first example of a method for producing a glass plate according to an embodiment of the present invention is carried out. [Figure 7] FIG. 2 is a schematic plan view showing a state in which a second example of a method for producing a glass plate according to an embodiment of the present invention is carried out. [Figure 8]FIG. 4 is a schematic plan view showing a state in which a third example of a method for producing a glass plate according to an embodiment of the present invention is carried out. [Figure 9] FIG. 11 is a schematic plan view showing a state in which a fourth example of a method for producing a glass plate according to an embodiment of the present invention is carried out. [Figure 10] FIG. 13 is a schematic plan view showing a state in which a fifth example of a method for producing a glass plate according to an embodiment of the present invention is implemented. [Figure 11] FIG. 13 is a schematic plan view showing a state in which a sixth example of a method for producing a glass plate according to an embodiment of the present invention is carried out. [Figure 12] FIG. 13 is a schematic plan view showing a state in which a seventh example of a method for producing a glass plate according to an embodiment of the present invention is carried out. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] Hereinafter, a method for producing a glass sheet according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0040] 1 is a plan view showing a state in which a glass sheet manufacturing method according to an embodiment of the present invention is carried out using a glass sheet manufacturing apparatus 1. First, the glass sheet manufacturing apparatus 1 will be described with reference to the drawing.

[0041] The glass sheet manufacturing apparatus 1 includes two processing units 2. Each of these processing units 2 includes a moving base 3, an abnormality detection device 4, and two edge surface processing devices 5. In this embodiment, the two processing units 2 are configured to move in the X direction in the figure with a rectangular glass sheet G set in a fixed position.

[0042] The two processing units 2 are arranged corresponding to end faces Ga1 (hereinafter referred to as first end faces Ga1) of a pair of first sides Ga along the X direction of the glass sheet G. The abnormality detection device 4 and the two end face processing devices 5 in the two processing units 2 are both held on a single moving base 3. Therefore, the abnormality detection device 4 and the two end face processing devices 5 in the two processing units 2 are both configured to move integrally in the X direction. When the two processing units 2 move in the X direction, one abnormality detection device 4 first contacts the first end face Ga1 of the glass sheet G, and then the two end face processing devices 5 contact the first end face Ga1 of the glass sheet G in turn.

[0043] In addition, since the upper and lower processing units 2 in the figure have substantially the same configuration, the following description will be given taking the lower processing unit 2 as an example.

[0044] The abnormality detection device 4 in the processing unit 2 is configured to contact not only the first end face Ga1 of the glass sheet G, but also one end face Gb2 (hereinafter referred to as the second end face Gb2) of the end faces Gb1, Gb2 of a pair of second sides Gb along the Y direction perpendicular to the X direction. The second end face Gb2 is the rear end face of the end faces Gb1, Gb2 in the X direction (movement direction).

[0045] More specifically, the abnormality detection device 4 includes a roller 6 which is a contactor that contacts the second end face Gb2 of the glass sheet G and then contacts the first end face Ga1. As shown in FIG. 2, the contactor 6 is configured as a cylindrical roller in this embodiment. The diameter of the roller 6 is 10 to 500 mm. As shown in the figure, the roller 6 is attached to the tip of an arm member 7 via a support shaft 8. The roller 6 may be a free roller that rotates around the support shaft 8, but in this embodiment, it is fixed to the tip of the arm member 7. The material of at least the outer periphery of the roller 6 is preferably resin, but may also be metal such as aluminum, hard rubber, or the like.

[0046] Furthermore, the abnormality detection device 4 includes a servo motor 9 that swings the arm member 7 so as to change the angle. The servo motor 9 has a motor shaft 9a that can rotate in forward and reverse directions. The base end of the arm member 7 is connected to the motor shaft 9a of the servo motor 9. Therefore, the arm member 7 can swing within a plane along the main surface G1 of the glass sheet G in accordance with the rotation of the motor shaft 9a.

[0047] The arm member 7 is configured to change its posture between an upright posture in which it extends in a direction along the second end face Gb2 of the glass sheet as shown by a chain line in the figure, and an inclined posture in which it extends in an inclined direction as shown by a solid line in the figure, in accordance with the rotation of the motor shaft 9a of the servo motor 9. The arm member 7 is biased by the servo motor 9 in a direction in which it moves from the inclined posture to the upright posture. In this case, when the arm member 7 is in the upright posture, the clockwise swing of the arm member 7 is restricted by a stopper (not shown).

[0048] With this configuration, as shown by the solid line in the figure, while the abnormality detection device 4 moves in the X direction in conjunction with the movement of the processing unit 2, the roller 6 is pressed against the first end face Ga1 of the glass sheet G while being urged toward the first end face Ga1 by the arm member 7. In this state, the roller 6 moves on the first end face Ga1. Also, as shown by the chain line in the figure, when the abnormality detection device 4 moves in the X direction from a state in which the roller 6 is in contact with the second end face Gb2 of the glass sheet G, the roller 6 is pressed against the second end face Gb2 of the glass sheet G while being urged toward the second end face Gb2 by the arm member 7. In this state, the roller 6 moves on the second end face Gb2 while the arm member 7 gradually tilts.

[0049] In this case, the X-direction position and Y-direction position of the roller 6 with respect to the machining unit 2 as a reference are calculated from the angle α between a straight line L1 along the Y direction and a center line L2 of the arm member 7 (a straight line L2 connecting the support shaft 8 and the motor shaft 9a in the illustrated example). In this embodiment, since the base end of the arm member 7 is directly connected to the motor shaft 9a of the servo motor 9, the angle α is the rotation angle of the motor shaft 9a. In this case, the position of the roller 6 is calculated by a control unit 10 of the servo motor 9. The servo motor 9 is fixed to an assembly base 11.

[0050] 3 illustrates the states of the roller 6 and the arm member 7 in the process in which the abnormality detection device 4 moves in the X direction in accordance with the movement of the machining unit 2. As shown by the solid line in the figure, when the roller 6 comes into contact with the second end face Gb2 of the glass sheet G, the arm member 7 is maintained in an upright position. From this state, the roller 6 climbs over the corner Gc between the second end face Gb2 and the first end face Ga1 of the glass sheet G as shown by the reference character A in the figure, and reaches the first end face Ga1 of the glass sheet G as shown by the reference character B in the figure. When the roller 6 climbs over the corner Gc and when it reaches the first end face Ga1, the arm member 7 is in an inclined position.

[0051] As shown in FIG. 4, each of the two edge processing devices 5 includes a motor 13 that rotates and drives a grindstone 12 as a processing tool, a support member 14 that rotatably supports the grindstone 12, and a first actuator (not shown) that generates a driving force for the grindstone 12 to press the first edge Ga1 of the glass sheet G. Each of the two edge processing devices 5 moves between a position shown by a solid line in the figure and a position shown by a chain line in the figure by the operation of a second actuator (not shown). The state shown by the solid line in the figure is a state in which the grindstone 12 is processing the first edge Ga1 of the glass sheet G. The state shown by the chain line in the figure is a state in which the grindstone 12 is retracted from the first edge Ga1 of the glass sheet G. In this case, the movement of the two edge processing devices 5 is performed while being guided by a guide member (not shown). These guide members are fixed to the moving base 3. Both of the two end surface processing devices 5 move linearly along the Y direction on a plane parallel to the surface 3a of the movable base 3. Furthermore, the two end surface processing devices 5 are each capable of moving independently.

[0052] The motor 13 may be, but is not limited to, a synchronous motor, an induction motor, a servo motor, etc. The first actuator may be, but is not limited to, a coreless linear motor from the viewpoint of compactness, etc. The second actuator may be, but is not limited to, an air cylinder, a linear cylinder using a ball screw mechanism, etc.

[0053] The grindstone 12 that processes the first end face Ga1 of the glass sheet G first is for grinding (rough processing) and has a large pressing force (contact pressure) on the first end face Ga1. The grindstone 12 that processes the first end face Ga1 later is for polishing (finish processing) and has a smaller pressing force (contact pressure) on the first end face Ga1 than the grindstone 12 for grinding. All of these grindstones 12 are controlled so that the pressing force on the first end face Ga1 is constant. In addition, the pressing force of each of these grindstones 12 on the first end face Ga1 is greater than the pressing force of the roller 6 described above. The grain size of the abrasive grains in the grindstone 12 for polishing is the same as or larger than the grain size of the abrasive grains in the grindstone 12 for grinding. The grain size of the abrasive grains in the grinding wheel 12 for grinding can be, for example, #100 to #1000, and the grain size of the abrasive grains in the polishing wheel 12 can be, for example, #200 to #3000. The diameter of each of these grinding wheels 12 is, for example, 100 to 200 mm.

[0054] The direction in which the grindstones 12 move between the processing position P1 and the retreat position P2 is the Y direction. The lower limit of a distance M1 between the processing position P1 of the grindstones 12 when processing the first end face Ga1 of the glass sheet G and the retreat position P2 of the grindstones 12 when retreating from the first end face Ga1 of the glass sheet G is preferably 50 mm, more preferably 80 mm. The upper limit of the distance M1 is preferably 500 mm, more preferably 300 mm.

[0055] 5, an assembly base 11 of the abnormality detection device 4 is fixed to the movable base 3. Therefore, the abnormality detection device 4 and the two end face processing devices 5 are configured to move integrally in the X direction.

[0056] The glass sheet manufacturing apparatus 1 also includes a control device (not shown). The control device includes a storage unit that stores various pieces of positional information, a calculation unit that calculates the positions of the above-mentioned components based on the various pieces of positional information, and a main control unit that controls the operation of each component based on the positions.

[0057] Next, a method for producing a glass sheet using the glass sheet producing apparatus 1 having the above configuration will be described.

[0058] This manufacturing method includes a preparation step of setting a glass sheet G at a fixed position, an edge processing step of processing a pair of first edge faces Ga1 of the glass sheet G, an abnormality detection step of detecting an abnormality in the glass sheet G, and an interruption step of interrupting the edge processing step when an abnormality is detected in the glass sheet G. Note that, after the edge processing step, steps such as cleaning, inspection, and packaging of the glass sheet G may be performed.

[0059] In the preparation step, the glass sheet G is fixed by any method such as suction on a mounting table (e.g., a surface plate) arranged at a fixed position. At this time, the processing unit 2 waits upstream of the second end surface Gb2 of the glass sheet G (left side in FIG. 1). In the following description, this waiting position is referred to as the initial position. The initial position is stored as position information in the memory unit of the control device. In addition, the processing position P1 and the retreat position P2 described above are also stored as position information in the memory unit of the control device.

[0060] The glass plate G is obtained by obtaining a forming original plate by a predetermined forming method, and then cutting the forming original plate to a predetermined size. As the forming method, for example, down-draw methods such as overflow down-draw method, slot down-draw method, and re-draw method, and a float method can be used. Among them, the overflow down-draw method is preferable because the surfaces on both sides are high quality. The glass plate G is cut out, for example, by forming scribe lines on the forming original plate and folding the forming original plate along the scribe lines. In this case, a pair of first end faces Ga1 and a pair of second end faces Gb2 of the glass plate G are surfaces formed by folding. The glass plate G is used, for example, as a glass substrate for a flat panel display such as a liquid crystal display.

[0061] The glass plate G has a rectangular plate shape. The thickness of the glass plate G is, for example, preferably 0.05 to 10 mm, and more preferably 0.2 to 0.7 mm. Of course, the glass plate G to which the present invention can be applied is not limited to the above-mentioned form. For example, the present invention can be applied to glass plates having shapes other than a rectangle (e.g., a polygon) and glass plates having a thickness outside the range of 0.05 to 10 mm.

[0062] Hereinafter, first to seventh examples of the present manufacturing method (in particular, first to seventh examples of the end face processing step, the abnormality detection step, and the interruption step) will be described.

[0063] 6 is a schematic plan view showing a first example of the present manufacturing method. As shown in FIG. 6, in this first example, an abnormality in the glass sheet G is a recess Gx such as a crack or chip on one of the first end faces Ga1 (the lower first end face Ga1 in FIG. 6). This recess Gx cannot be removed by the grindstone 12.

[0064] Furthermore, in this first example, the abnormality detection step is performed during the end face processing step, and the stop step is performed after the abnormality detection step. In detail, in the end face processing step, as the processing unit 2 moves in the X direction, the two grindstones 12 grind and polish the first end face Ga1 in sequence as shown by solid lines in the figure, and prior to this, the roller (contact) 6 moves in contact with the first end face Ga1. At this time, the abnormality detection step is performed. Then, in the process of the roller 6 entering the recess Gx, the stop step is performed at the point when the position of the roller 6 in the Y direction is displaced from the normal position to the center side in the Y direction of the glass sheet G. Here, "displaced from the normal position to the center side in the Y direction of the glass sheet G" strictly means that the roller 6 is displaced from the normal position to the center side in the Y direction of the glass sheet G beyond a predetermined threshold value. This threshold value is set to 0.1 to 10 mm. The normal position and threshold value are stored as position information in the storage unit of the control device. It should be noted that the position of the roller 6 in the Y direction here is the position of the roller 6 in the Y direction calculated by the control unit 10 of the servo motor 9 from the angle α.

[0065] In the stop step, the two grindstones 12 are retreated from the processing position P1 to the retreat position P2. At this time, the roller 6 may also be retreated to a retreat position away from the first end face Ga1, but since the pressing force from the roller 6 to the first end face Ga1 is significantly smaller than that of the two grindstones 12, it may be left as it is. This prevents problems such as damage to the glass sheet G starting from the recess Gx of the first end face Ga1. In addition, the retreat of the grindstones 12 to the retreat position P2 is performed in the shortest time, thereby improving productivity. Furthermore, the movement of the processing unit 2 in the X direction may be stopped at the same time as the retreat of the grindstones 12 to the retreat position P2, and the processing unit 2 may be returned to the initial position.

[0066] After the interruption step is performed, the glass plate G is discarded. Alternatively, the recess Gx on the first end face Ga1 can be removed to make a smaller-sized glass plate (product) and reused.

[0067] FIG. 7 is a schematic plan view showing the implementation state of the second example of the present manufacturing method. As shown in the figure, the second example differs from the first example described above in that a convex portion Gy such as a cut-out portion is generated on one of the first end faces Ga1 (the lower first end face Ga1 in the figure) as an abnormality of the glass sheet G. This convex portion Gy cannot be removed by the grindstone 12. Therefore, according to the second example, the stopping step is executed at the point when the position of the roller 6 in the Y direction is displaced from the normal position to the outside in the Y direction of the glass sheet G in the process of the roller 6 climbing up the convex portion Gy. Here, "displaced from the normal position to the outside in the Y direction of the glass sheet G" strictly means that the glass sheet G is displaced from the normal position to the outside in the Y direction of the glass sheet G by exceeding a predetermined threshold value. This threshold value is set to 0.1 to 10 mm. Other matters are the same as those described in the first example described above.

[0068] FIG. 8 is a schematic plan view showing the implementation status of the third example of the present manufacturing method. The dotted line in the figure indicates the contour shape of the glass sheet G when there is no abnormality (the same applies to the following FIGS. 9 to 12). In this third example, as an abnormality of the glass sheet G, the positions of the pair of second end faces Gb2 of the glass sheet G are both shifted by the dimension a in the X direction. In other words, the glass sheet G is shifted by the dimension a on the rear side in the moving direction of the processing unit 2. In this third example, the abnormality detection process is performed before the end face processing process is performed (the same applies to the following fourth to seventh examples). The abnormality detection process is performed in the process in which the roller 6 contacts the second end face Gb2 of the glass sheet G as shown in the figure, more specifically, in the process in which the roller 6 applies a pressing force to the second end face Gb2, when the processing unit 2 moves from the initial position in the X direction. Specifically, in this abnormality detection process, when the pair of rollers 6 contact the second end face Gb2 of the glass sheet G at the same position and the position is different from the normal position, it is determined that the glass sheet G is abnormal. The above "same position" strictly means that the difference between the positions is below a predetermined threshold. This threshold is set to, for example, 5 mm or less, preferably 2 mm or less. Moreover, the above "when different from the normal position" strictly means that the position is different from the normal position by more than a predetermined threshold. This threshold is set to, for example, 10 mm or more, preferably 15 mm or more. The above normal position and the two thresholds are stored as position information in the storage unit of the control device. The above position when the abnormality detection process is performed can also be grasped by detecting the time. In the abnormality detection process in this case, when the pair of rollers 6 contact the second end surface Gb2 of the glass sheet G at the same time and the time is different from the normal time, it is determined that the glass sheet G is abnormal. The above "same time" strictly means that the difference between the two times is below a predetermined threshold. This threshold can be calculated from the threshold at the above "same position" according to the moving speed of the processing unit 2. Moreover, the above "when different from the normal time" strictly means that the position is different from the normal time by more than a predetermined threshold. This threshold value can also be calculated from the threshold value in the case where the position is different from the normal position described above, depending on the moving speed of the machining unit 2. Here, the position of the roller 6 in the X direction is calculated based on the initial position.Therefore, the position of the roller 6 in the X direction is determined based on the position of the processing unit 2 in the X direction, which is determined by the moving distance from the initial position, and the position of the roller 6 in the X direction, which is determined by the control unit 10 of the servo motor 9 from the angle α, based on the processing unit 2. In this third example, when the roller 6 contacts the second end face Gb2 of the glass sheet G, the angle α becomes 0° or approximately 0°. Then, as the processing unit 2 moves further in the X direction, the roller 6 moves along the second end face Gb2, so the angle α becomes larger. That is, whether or not a positional deviation occurs in the X direction can be determined from the position where the angle α starts to change from 0° and the normal position stored in the storage unit of the control device. Then, if the above-mentioned abnormality of the glass sheet G is detected in the abnormality detection step, the movement of the pair of processing units 2 in the X direction is stopped in the stop step. After the stop step is performed, the pair of processing units 2 is returned to the initial position to correct the above-mentioned positional deviation of the glass sheet G, and then the end face processing step is performed on the pair of first end faces Ga1 of the glass sheet G. In this way, when the pair of rollers 6 are in contact with the second end face Gb2 of the glass sheet G, the movement of the pair of processing units 2 in the X direction is stopped, so that it is possible to avoid with sufficient time the inconvenience of the pair of first end faces Ga1 of the glass sheet G being inappropriately ground and polished by the grindstone 12. This makes it possible to increase the movement speed of the processing units 2 in the X direction, thereby improving productivity.

[0069] In the above third example, a case was described in which a positional shift of the glass plate G occurs on the rear side of the movement direction of the processing unit 2, but this third example can also be applied in a similar manner to a case in which a positional shift of the glass plate G occurs on the front side of the movement direction of the processing unit 2.

[0070] FIG. 9 is a schematic plan view showing the implementation state of the fourth example of the manufacturing method. In this fourth example, as an abnormality of the glass sheet G, the positions of the pair of first end faces Ga1 of the glass sheet G are shifted by a dimension b in the same direction along the Y direction. In other words, the glass sheet G is shifted by a dimension b to the lower side in the figure. The abnormality detection process is performed in the process in which the roller 6 contacts the second end face Gb2 of the glass sheet G as shown by a chain line in the figure and then reaches the first end face Ga1 of the glass sheet G as shown by a solid line in the figure when the processing unit 2 moves from the initial position to the X direction. Specifically, in this abnormality detection process, when the pair of rollers 6 contact the pair of first end faces Ga1 of the glass sheet G, the positions of the pair of rollers 6 in the Y direction are both different from the normal positions and the interval between the pair of rollers 6 is the same as the normal interval, it is determined that the glass sheet G is abnormal. Strictly speaking, the above "different from the normal position" means that the position is different from the normal position by more than a predetermined threshold value. This threshold is set to, for example, 10 mm or more, preferably 15 mm or more. The above "if the distance is the same as the normal distance" strictly means that the distance is less than a predetermined threshold with respect to the normal distance. This threshold is set to, for example, 5 mm or less, preferably 2 mm or less. The normal position, the normal distance, and the two thresholds are stored as position information in the storage unit of the control device. In this case, the Y-direction position of the pair of rollers 6 when in contact with the pair of first end faces Ga1 of the glass sheet G is calculated from the angle α by the control unit 10 of each servo motor 9. Here, the Y-direction position of the processing unit 2 is always constant. Therefore, in order to recognize the Y-direction position of the rollers 6, it is not necessary to consider the Y-direction position of the processing unit 2. The X-direction position of the pair of rollers 6 when determining whether the glass sheet G is displaced in the same direction along the Y direction is the position when the pair of rollers 6 are separated from the corner Gc of the glass sheet G by a predetermined length M2 (for example, 10 to 50 mm) in the X-direction. If the above-mentioned abnormality of the glass sheet G is detected during this determination, all the grindstones 12 are retracted to the retracted position P2 in the abort step. In this case, when the pair of rollers 6 are spaced apart from the corners Gc of the glass sheet G in the X direction by the above-mentioned predetermined length M2, none of the grindstones 12 have reached the pair of first end faces Ga1 of the glass sheet G.Therefore, by retracting all the grindstones 12 to the retracted position P2 at this time, it is possible to avoid a problem in which the pair of first end faces Ga1 of the glass sheet G are inappropriately ground and polished by the grindstones 12. After the execution of this interruption step, the pair of processing units 2 are returned to their initial positions, the above-mentioned positional deviation of the glass sheet G is corrected, and then the end face processing step is performed on the pair of first end faces Ga1 of the glass sheet G. Alternatively, even after the execution of the interruption step, the processing units 2 may be continuously moved to the movement end position and then returned to their initial positions, the above-mentioned positional deviation of the glass sheet G is corrected, and the end face processing step may be performed on the pair of first end faces Ga1 of the glass sheet G.

[0071] In the above fourth example, a case where a positional shift of the glass plate G occurs on the lower side in Figure 9 is described. However, this fourth example can also be applied in the same manner to a case where a positional shift of the glass plate G occurs on the upper side in Figure 9.

[0072] FIG. 10 is a schematic plan view showing the implementation state of the fifth example of the present manufacturing method. In this fifth example, as an abnormality of the glass sheet G, the position of one first end face Ga1 of the glass sheet G is shifted by a dimension c in the direction away from the center of the glass sheet G in the Y direction, and the position of the other first end face Ga1 is shifted by a dimension d in the direction away from the center of the glass sheet G in the Y direction. In other words, the glass sheet G has a deviation in the dimension along the Y direction. The abnormality detection process is performed in the process in which the roller 6 contacts the second end face Gb2 of the glass sheet G as shown by the chain line in the figure and then reaches the first end face Ga1 of the glass sheet G as shown by the solid line in the figure when the processing unit 2 moves from the initial position to the X direction. Specifically, in this abnormality detection process, when the pair of rollers 6 contact the pair of first end faces Ga1 of the glass sheet G, the case where the interval between the pair of rollers 6 is different from the normal interval is determined to be an abnormality of the glass sheet G. The above "when the interval is different from the normal interval" strictly means when the interval is different from the normal interval by more than a predetermined threshold value. This threshold value is set, for example, to 0.5 mm or more, preferably 1 mm or more. The above normal interval and threshold value are stored as position information in the storage unit of the control device. In this case, the Y-direction position of the pair of rollers 6 when in contact with the pair of first end faces Ga1 of the glass sheet G is determined in the same manner as in the fourth example described above. In addition, the X-direction position of the pair of rollers 6 when determining whether the glass sheet G is abnormal or not is also determined in the same manner as in the fourth example described above. Furthermore, when the above-mentioned abnormality of the glass sheet G is detected in the abnormality detection step, in the suspension step, all the grindstones 12 are retreated to the retreat position P2, and the timing of retreating all the grindstones 12 are the same as those described in the fourth example described above. Therefore, in this fifth example as well, the problem that the pair of first end faces Ga1 of the glass sheet G are unfairly ground and polished by the grindstones 12 can be avoided. In this fifth example, the glass sheet G is discarded after the suspension step is performed. Therefore, after the abort process is performed, the processing unit 2 is returned to its initial position (including the case where it is returned to its initial position via the movement end position) and all the grinding wheels 12 are returned to the processing position P1, and then the processing unit 2 is moved again in the X direction to perform the end face processing process on a pair of first end faces Ga1 of the subsequent glass sheet G that is free of abnormalities.In addition, the glass plate G may be reused by adjusting the size thereof, instead of being discarded.

[0073] In the above fifth example, a case was described in which the length of the glass plate G along the Y direction is longer than the normal length. However, this fifth example can also be applied in a similar manner to a case in which the length of the glass plate G along the Y direction is shorter than the normal length.

[0074] FIG. 11 is a schematic plan view showing the implementation state of the sixth example of the present manufacturing method. In this sixth example, as an abnormality of the glass sheet G, a pair of first end faces Ga1 and a pair of second end faces Gb2 of the glass sheet G are inclined. In other words, the glass sheet G is in an inclined posture due to a deviation in posture. The abnormality detection process is performed in the process in which the pair of rollers 6 contact the second end faces Gb2 of the glass sheet G when the processing unit 2 moves from the initial position in the X direction. In this abnormality detection process, a case in which the positions of one roller 6 and the other roller 6 when they contact the second end faces Gb2 are different is regarded as an abnormality of the glass sheet G. The above "case in which the positions are different" strictly means a case in which the difference between the position when one roller 6 contacts the second end faces Gb2 and the position when the other roller 6 contacts the second end faces Gb2 exceeds a predetermined threshold. This threshold is set to, for example, 0.5 mm or more, preferably 1 mm or more. This threshold is stored as position information in the storage unit of the control device. The above position when the abnormality detection process is performed can also be grasped by detecting time. In the abnormality detection process in this case, the glass sheet G is determined to be abnormal when the timings at which one roller 6 and the other roller 6 contact the second end surface Gb2 of the glass sheet G differ. Strictly speaking, the above "when the timings differ" means when the timings differ by more than a predetermined threshold. This threshold can be calculated from the threshold in the above "when the positions differ" according to the moving speed of the processing unit 2. In this case, the position of the roller 6 in the X direction when it contacts the second end surface Gb2 of the glass sheet G is obtained in the same manner as in the third example described above. In addition, when the above abnormality of the glass sheet G is detected in the abnormality detection process, the movement of the pair of processing units 2 in the X direction is stopped in the stopping process, which is the same as in the third example described above. Then, after the stopping process is performed, the pair of processing units 2 are returned to their initial positions, and the above-mentioned deviation in the attitude of the glass sheet G is corrected, and then the end surface processing process is performed on the pair of first end surfaces Ga1 of the glass sheet G.

[0075] In the above sixth example, the case has been described in which the glass plate G is inclined so that the first end face Ga1 moves toward the upper side in FIG. 11 as it moves in the X direction. However, this sixth example can also be applied in a similar manner to the case in which the glass plate G is inclined so that the first end face Ga1 moves toward the lower side in FIG. 11 as it moves in the X direction.

[0076] FIG. 12 is a schematic plan view showing the implementation state of the seventh example of the present manufacturing method. In this seventh example, as an abnormality of the glass sheet G, a pair of first end faces Ga1 and a pair of second end faces Gb2 of the glass sheet G are inclined. Therefore, this glass sheet G is inclined due to a deviation in posture, but the degree of inclination is greater than that of the sixth example. Therefore, in the abnormality detection process, when one roller 6 contacts the second end face Gb2 of the glass sheet G and the other roller 6 contacts the first end face Ga1, it is determined that the glass sheet G is abnormal. As a method of determining whether one roller 6 contacts the second end face Gb2 of the glass sheet G and the other roller 6 contacts the first end face Ga1, the difference between the rate of change of one roller 6 in the Y direction when the roller 6 moves in the X direction and the rate of change of the other roller 6 in the Y direction is compared. Specifically, in FIG. 12, the angle α between the line extending from one roller 6 in the X direction and the first end face Ga1 is smaller than the angle β between the line extending from the other roller 6 in the X direction and the second end face Gb2, so the rate of change in the Y direction when one roller 6 moves in the X direction is small. In this case, the position in the X direction when one roller 6 contacts the second end face Gb2 is obtained in the same manner as in the third example described above. In addition, the position in the X direction of the roller 6 when the other roller 6 contacts the first end face Ga1 and is judged to be abnormal is obtained in the same manner as in the fourth example described above. Then, as in the sixth example described above, if the above-mentioned abnormality of the glass sheet G is detected in the abnormality detection step, the movement of the pair of processing units 2 in the X direction is stopped in the stop step. In addition, after the stop step is performed, the pair of processing units 2 are returned to their initial positions, and the above-mentioned deviation in the attitude of the glass sheet G is corrected, and then the end face processing step is performed on the pair of first end faces Ga1 of the glass sheet G.

[0077] In the above seventh example, the case has been described in which the glass plate G is inclined so that the first end face Ga1 moves toward the upper side in FIG. 12 as it moves in the X direction. However, this seventh example can also be applied in a similar manner to the case in which the glass plate G is inclined so that the first end face Ga1 moves toward the lower side in FIG. 12 as it moves in the X direction.

[0078] The above describes the method for manufacturing a glass plate 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.

[0079] For example, in the above embodiment, the glass sheet G is set at a fixed position, and the abnormality detection device 4 and the edge processing device 5 are moved in the X direction as the processing unit 2. However, the abnormality detection device 4 and the edge processing device 5 may be set at a fixed position (not necessarily as the processing unit 2), and the glass sheet G may be moved in the opposite direction to the X direction. In this case, it is preferable to move a plurality of glass sheets G in sequence. As a moving method, it is preferable to sandwich each glass sheet G with belts extending in the moving direction from both the front and back sides so that the entire first end face Ga1 and a part of the second end face Gb2 of each glass sheet G are exposed, and to transport each glass sheet G with the belts. In this case, the transport speed of each glass sheet G can be increased, so that the roller 6 of the abnormality detection device 4 may collide with the second end face Gb2 of the glass sheet G, causing a malfunction such as damage to the abnormality detection device 4. Therefore, in this case, the arm member 7 of the abnormality detection device 4 is always kept in an inclined state, and the roller 6 is configured to contact the corner portion Gc and then contact the first end face Ga1 without contacting the second end face Gb2. Note that even in this case, the roller 6 may be brought into contact with the second end face Gb2 if the conveying speed at which each glass sheet G approaches the abnormality detection device 4 is approximately the same as the speed at which the abnormality detection device 4 and the edge face processing device 5 are moved with the glass sheet G set in a fixed position.

[0080] In the above embodiment, the number of edge processing devices 5 corresponding to one first end face Ga1 of the glass sheet G is two, but the number of edge processing devices 5 may be one or three or more. When the number is three or more, the pressing force (contact pressure) from all the grindstones 12 of the edge processing devices 5 to the first end face Ga1 is greater than the pressing force (contact pressure) from the roller 6 to the first end face Ga1.

[0081] In the first and second examples of the manufacturing method in the above embodiment, the abnormality detection device 4 and the edge surface processing device 5 are arranged corresponding to a pair of first end surfaces Ga1 of the glass plate G, respectively, but the abnormality detection device 4 and the edge surface processing device 5 may be arranged corresponding to only one of the first end surfaces Ga1. [Explanation of symbols]

[0082] 1. Glass plate manufacturing equipment 2 Processing unit 3 Mobile base 4. Anomaly detection device 5 Edge processing equipment 6 Roller (contact) 7 Arm parts 9. Servo motor 12 Grindstone (tool) G Glass plate Ga First side of glass plate Ga1 First end face of glass plate (first side end face) Gb Second edge of glass plate Gb1: The other end face of the second side of the glass plate Gb2: Second end face of the glass plate (one end face of the second side of the glass plate) Gx Concave (anomaly occurring on the first edge of the glass plate) Gy Convex part (abnormality occurring on the first edge surface of the glass plate) α Arm component angle

Claims

1. A method for manufacturing a glass plate, comprising: an edge processing step of processing an edge of a first side of the glass plate extending in a direction of the relative movement of the processing tool by contacting the processing tool with the edge of the first side of the glass plate while moving the processing tool relative to the glass plate; an abnormality detection process in which a contactor of an abnormality detection device that moves relative to the glass plate together with the processing tool and is configured to contact the end face of a first side of the glass plate before the processing tool does is brought into contact with at least one of the end faces of the first side and the end face of a second side perpendicular to the end face of the first side of the glass plate to detect an abnormality in the glass plate; a stop step of stopping the edge processing step when an abnormality in the glass plate is detected in the abnormality detection step.

2. the abnormality of the glass plate is a convex portion or a concave portion partially occurring on an end surface of a first side of the glass plate, The abnormality detection step is carried out during the end face processing step, 2. The method for manufacturing a glass plate according to claim 1, wherein in the abnormality detection step, a case in which the contactor climbs onto the convex portion or enters into the concave portion is determined to be an abnormality in the glass plate.

3. 3. The method for manufacturing a glass plate according to claim 2, wherein in the interruption step, the processing tool is retreated to a position where it does not interfere with the glass plate, and after the interruption step is performed, the glass plate is discarded or reused by removing the convex portion or the concave portion.

4. 4. The method for manufacturing a glass sheet according to claim 1, wherein the contactor exerts a smaller contact pressure on the end face of the first side of the glass sheet than the processing tool.

5. the abnormality detection device includes a swingable arm member, the contactor is attached to a tip of the arm member and biased toward an end face of a first side of the glass plate, The method for manufacturing a glass plate according to any one of claims 1 to 3, characterized in that the glass plate is set in a fixed position, and the processing tool and the arm member are held by a single movable base and move integrally.

6. The edge processing step is performed by bringing the pair of processing tools into contact with edge surfaces of a pair of first sides of the glass plate, The method for manufacturing a glass sheet according to claim 1 , wherein the abnormality detection step is performed before the edge processing step is performed.

7. The abnormality of the glass plate is an abnormality in the position of the glass plate with respect to a direction along a first edge, 7. The method for manufacturing a glass plate according to claim 6, wherein in the abnormality detection process, a pair of the contacts contact an end face of one of the second sides of the glass plate at the same position in a direction along the first side, and the position is different from a normal position, the glass plate is judged to be abnormal.

8. The method for manufacturing a glass plate according to claim 7, characterized in that in the interruption process, the relative movement between the pair of processing tools and the glass plate is interrupted, and after the interruption process is performed, the positional abnormality is corrected and the edge processing process is performed on the glass plate.

9. The abnormality of the glass sheet is an abnormality in the position of the glass sheet with respect to a direction along the second side, 7. The method for manufacturing a glass plate according to claim 6, wherein in the abnormality detection process, when the pair of contacts are in contact with the end faces of a pair of first sides of the glass plate, if any of the positions of the pair of contacts in a direction along the second side of the glass plate is different from a normal position and the distance between the pair of contacts is the same as the normal distance, the glass plate is deemed to be abnormal.

10. The method for manufacturing a glass plate according to claim 9, characterized in that, in the interruption process, the pair of processing tools are retreated to a position where they do not interfere with the glass plate, and after the interruption process is performed, the positional abnormality is corrected and the edge processing process is performed on the glass plate.

11. The abnormality of the glass plate is a dimensional deviation of the glass plate in a direction along the second side, 7. The method for manufacturing a glass plate according to claim 6, characterized in that in the abnormality detection process, when the pair of contacts are in contact with the end faces of a pair of first sides of the glass plate, a case in which the spacing between the pair of contacts is different from a normal spacing is determined to be an abnormality in the glass plate.

12. The method for manufacturing a glass plate according to claim 11, characterized in that, in the interruption step, the pair of processing tools are retreated to a position where they do not interfere with the glass plate, and after the interruption step is performed, the glass plate is discarded or the size of the glass plate is adjusted and reused.

13. The abnormality of the glass plate is a misalignment of the glass plate such that the glass plate is in an inclined position, 7. The method for manufacturing a glass plate according to claim 6, wherein in the abnormality detection process, an abnormality is detected in the glass plate when one contactor and the other contactor of a pair of contacts contact an end face of one of the second sides of the glass plate at different positions in a direction along the first side, or when one contactor contacts an end face of the one of the second sides of the glass plate and the other contactor contacts an end face of the first side of the glass plate.

14. The method for manufacturing a glass plate according to claim 13, characterized in that in the interruption process, the relative movement between the pair of processing tools and the glass plate is interrupted, and after the interruption process is performed, the misalignment of the posture is corrected and the edge processing process is performed on the glass plate.

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