Method for manufacturing a glass article

Abstract

A method for manufacturing a glass article, comprising: a forming step (P1) of forming a glass ribbon (2) from molten glass (6); and a conveying step (P2) of conveying the glass ribbon (2) along a conveying path, wherein, in the conveying step (P2), a first roller (9a) and a second roller (9b) are disposed to respectively contact and convey one end portion (2s) and the other end portion (2t) in the width direction of the glass ribbon (2), and a speed difference is provided between the first roller (9a) and the second roller (9b).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing glass articles. Background Art

[0002] In glass substrates used in displays such as liquid crystal displays, plasma displays, and organic EL displays, thinning is being promoted in response to increasing requirements for weight reduction. As a result, glass films thinned to a thickness of 300 μm or less or 200 μm or less have been developed and manufactured.

[0003] As an example of a method for manufacturing a glass film, Patent Document 1 discloses a manufacturing method using a drawing method typified by an overflow down-draw method, a redraw method, a slot down-draw method, etc.

[0004] In the method disclosed in this document, first, a glass ribbon (ribbon-shaped glass film) that is a raw material for the glass film is formed (forming step) using the drawing method. Next, after the formed glass ribbon is transported longitudinally (longitudinal transport step), it is transported along a curved transport path so that its transport direction is changed from longitudinal to lateral (transport direction change step). At the time of this transport direction change, a roller conveyor composed of a plurality of rollers arranged along the curved transport path is used. After that, while the glass ribbon whose transport direction has been changed is transported laterally (lateral transport step), unnecessary portions existing at both ends in the width direction of the glass ribbon are cut off and separated (separation step). Furthermore, then, the glass ribbon from which the unnecessary portions have been separated is wound around a winding core in a roll shape to form a glass roll (winding step). The glass ribbon wound into a glass roll is then unwound from the winding core and cut along the width direction. Thus, a glass film is manufactured by cutting out from the glass ribbon.

[0005] In addition, in the above method, sometimes the glass ribbon that has passed through the longitudinal transport step enters the roller conveyor for performing the transport direction change step in a state of being improperly inclined with respect to its transport path. In this case, torsion occurs between the portion of the glass ribbon before passing through the roller conveyor and the portion after passing through the roller conveyor, and sometimes the glass ribbon breaks as a result.

[0006] Therefore, in order to solve the above problems, in the method disclosed in Patent Document 1, when performing the transport direction change step, a plurality of conveyors are arranged in parallel along the above transport path. Then, the glass ribbon is transported by the plurality of conveyors, and the transport speed based on each conveyor can be independently adjusted. In this way, a difference can be set in the transport speed of the glass ribbon between the plurality of conveyors. That is, each portion in the width direction of the glass ribbon transported by each conveyor can be transported at a different transport speed. By using this solution, torsion of the glass ribbon is avoided, and breakage of the glass ribbon is prevented.

[0007] Prior Art Documents

[0008] Patent Document

[0009] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-113342 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] In the above method, the torsion of the glass ribbon is avoided and the breakage of the glass ribbon can be prevented, but there are still problems to be solved. Here, the torsion of the glass ribbon is caused by the dimensional difference (the difference in length along the length direction of the glass ribbon) between one end and the other end in the width direction of the glass ribbon, and the dimensional difference between the two ends is caused by the different elongation amounts when forming the glass ribbon between one end and the other end.

[0012] Therefore, in the subsequent process of the transfer direction changing process, the torsion of the glass ribbon may occur again and the glass ribbon may break. That is, the following problem remains: when winding the glass ribbon around the winding core in the winding process, wrinkles or torsion occur on one side in the width direction of the glass ribbon, making it difficult to wind the glass ribbon. Therefore, in order to fundamentally eliminate the problems caused by the dimensional difference between the two ends, it is necessary to equalize the elongation amounts when forming the glass ribbon between one end and the other end in the width direction of the glass ribbon.

[0013] It should be noted that the problems caused by the dimensional difference between the two ends are not only problems that occur when manufacturing a glass film using the above method. Similar problems may occur when forming a glass ribbon in the manufacture of glass articles including glass plates having a larger thickness than the glass film. For example, in the case of cutting a glass ribbon that has undergone a longitudinal transfer process along the width direction while continuing to transfer it longitudinally and cutting out a glass plate from the glass ribbon, defects such as wrinkles and warping are formed along one side of the cut-out glass plate.

[0014] In view of the above situation, the technical problem of the present invention is to equalize the elongation amounts during forming between one end and the other end in the width direction of the glass ribbon when forming the glass ribbon in the manufacture of glass articles.

[0015] Solutions to the Problems

[0016] A method for manufacturing a glass article for solving the above problems includes: a forming process of forming a glass ribbon from molten glass; and a transfer process of transferring the glass ribbon along a transfer path. The method for manufacturing the glass article is characterized in that, in the transfer process, for the glass ribbon in a temperature region of 300°C or higher, a first roller and a second roller that are respectively in contact with and transfer one end and the other end in the width direction of the glass ribbon are arranged, and a speed difference is provided between the first roller and the second roller.

[0017] In this method, a speed difference can be set between a first roller at one end in the width direction of the glass ribbon being conveyed and a second roller at the other end during the conveying process. By setting such a speed difference, it is possible to change the balance of the elongation amounts between one end and the other end of the glass ribbon during forming. As a result, it is possible to equalize the elongation amounts of one end and the other end along with the change in the balance.

[0018] In the above method, preferably, it further includes: a measurement process in which, for a measurement target section that is a section along the length direction of the glass ribbon, the lengths from the leading end to the trailing end are respectively measured along one end and the other end of the glass ribbon to obtain a first measurement length and a second measurement length; and an adjustment process in which the speed difference between the first roller and the second roller is adjusted based on the dimensional difference between the first measurement length and the second measurement length.

[0019] In this way, by performing the measurement process, it is possible to quantitatively determine whether the elongation amounts of one end and the other end of the glass ribbon are sufficiently equalized based on the dimensional difference between the first measurement length and the second measurement length. By performing the adjustment process of adjusting the speed difference between the first roller and the second roller based on the result quantitatively obtained in this way, it is possible to equalize the elongation amounts of one end and the other end with high precision.

[0020] In the above method, preferably, when one end of the glass ribbon with a relatively long measurement length measured according to the result of the measurement process is set as the long-side end, and one end of the glass ribbon with a relatively short measurement length measured according to the result of the measurement process is set as the short-side end, in the adjustment process, the speed of the roller on the side corresponding to the long-side end among the first roller and the second roller is slowed down, and the speed of the roller on the side corresponding to the short-side end among the first roller and the second roller is increased.

[0021] In this way, by performing the adjustment process, the elongation amount of the long-side end is reduced and the elongation amount of the short-side end is increased, so that it is possible to efficiently equalize the elongation amounts of one end and the other end of the glass ribbon.

[0022] In the above method, preferably, the conveying process includes a cooling process of cooling one end and the other end of the glass ribbon while conveying the glass ribbon and an annealing process of annealing the glass ribbon after the cooling process while conveying it, and at least one of the cooling process and the annealing process uses the first roller and the second roller.

[0023] In the cooling process and the annealing process, the glass ribbon is in a state where the elongation amounts of one end portion and the other end portion can be adjusted. In particular, in the annealing process, it is easy to adjust the elongation amounts of one end portion and the other end portion. Therefore, if the first roller and the second roller are used in at least one of the cooling process and the annealing process, the elongation amounts of one end portion and the other end portion can be effectively equalized.

[0024] In the above method, preferably, the two rollers of the first roller and the second roller are taken as a group, and multiple groups are arranged along the conveying path.

[0025] In this way, a speed difference can be set between the first roller and the second roller at multiple positions on the conveying path of the glass ribbon, so that the effect of equalizing the elongation amounts of one end portion and the other end portion of the glass ribbon can be stably obtained.

[0026] In the above method, preferably, as the first roller and the second roller, a pair of rollers that sandwich the glass ribbon from the front and back sides are respectively used.

[0027] In this way, compared with the case where rollers are arranged only on the front side or only on the back side of the glass ribbon, by using a pair of rollers that sandwich the glass ribbon from the front and back sides, it is easier to adjust the elongation amounts of one end portion and the other end portion respectively by the first roller and the second roller. Thereby, the effect of equalizing the elongation amounts can be obtained more stably.

[0028] In the above method, it may also be that the glass ribbon is formed by the down-draw method.

[0029] In the down-draw method, problems caused by the dimensional difference between one end portion and the other end portion of the glass ribbon are likely to occur. Therefore, if the present invention is applied to the case where the glass ribbon is formed by the down-draw method, its effects can be appropriately enjoyed.

[0030] In the above method, it may also be that a winding process of winding the glass ribbon into a roll shape at the downstream end of the conveying path to form a glass roll is further included.

[0031] According to the above method, the elongation amounts of one end portion and the other end portion of the glass ribbon can be equalized, so that a glass ribbon with as small a dimensional difference between the two end portions as possible can be obtained after the conveying process. Therefore, by winding this glass ribbon in the winding process, a glass roll that does not have defects such as wrinkles or twists on one side in the width direction due to the dimensional difference between the two end portions can be obtained.

[0032] In addition, a method for manufacturing glass articles for solving the above-mentioned problems includes: a forming step of forming a glass ribbon by a down-drawing method; a longitudinal conveying step of conveying the glass ribbon in the longitudinal direction; a conveying direction conversion step of conveying the glass ribbon that has undergone the longitudinal conveying step along a curved conveying track, thereby converting the conveying direction of the glass ribbon from the longitudinal direction to the transverse direction; and a transverse conveying step of conveying the glass ribbon with the converted conveying direction in the transverse direction. The method for manufacturing glass articles is characterized in that, in the longitudinal conveying step, a first roller and a second roller are arranged to contact and convey one end and the other end of the glass ribbon in the width direction, respectively, and a speed difference is set between the first roller and the second roller.

[0033] Effects of the Invention

[0034] According to the present invention, when a glass ribbon is formed during production of a glass product, the amount of elongation during forming can be equalized between one end portion and the other end portion in the width direction of the glass ribbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a perspective view showing a glass roll.

[0036] Figure 2 It is a plan view showing a state in which the entire length of the glass ribbon constituting the glass roll is virtually unwound from the winding core.

[0037] Figure 3 It is a top view which shows the method of measuring the 1st length - the 3rd length of a glass ribbon.

[0038] Figure 4a It is a side view which shows the form of measuring the 1st length - the 3rd length of a glass ribbon.

[0039] Figure 4b It is a side view which shows the form of measuring the 1st length - the 3rd length of a glass ribbon.

[0040] Figure 4c It is a side view which shows the form of measuring the 1st length - the 3rd length of a glass ribbon.

[0041] Figure 5 It is a side view showing the manufacturing method of a glass article.

[0042] Figure 6 It is a top view showing a method for manufacturing a glass article.

[0043] Figure 7 This is a front view showing a method for manufacturing a glass article. DETAILED DESCRIPTION

[0044] Hereinafter, a method for producing a glass article according to an embodiment will be described with reference to the drawings.

[0045] <Glass Ribbon>

[0046] First, the glass ribbon manufactured by the manufacturing method of the glass article of this embodiment is described. The glass ribbon has an extremely long total length (length along the longitudinal direction), so the glass ribbon is usually rolled up to form a glass roll during storage and transportation.

[0047] like Figure 1 As shown, the glass roll 1 is wound around a winding core 4 in a state where a flexible glass ribbon 2 and a flexible belt-shaped protective sheet 3 for protecting the glass ribbon 2 from damage etc. overlap. The glass ribbon 2 is formed to have a substantially uniform thickness over the entire width, and as an example, the thickness is 300 μm or less. It should be noted that the thickness of the glass ribbon 2 is preferably 200 μm or less, more preferably 100 μm or less, and most preferably 50 μm or less. The lower limit of the thickness of the glass ribbon 2 is, for example, 10 μm. In addition, the total length of the glass ribbon 2 is, as an example, 100 m or more.

[0048] Here, in this embodiment, the width dimension of the strip-shaped protective sheet 3 is larger than the width dimension of the glass ribbon 2, but it is not limited to this. As a modification of this embodiment, the width dimensions of both 2 and 3 may be the same, or the width dimension of the glass ribbon 2 may be larger than the width dimension of the strip-shaped protective sheet 3.

[0049] If the entire length of the glass ribbon 2 constituting the glass roll 1 is virtually unwound from the winding core 4, the glass ribbon 2 is Figure 2 As shown in the figure, in the present glass ribbon 2, the leading end 2a which is one end in the longitudinal direction thereof and the rearward end 2b which is the other end thereof are each formed parallel to the width direction of the glass ribbon 2.

[0050] The glass ribbon 2 is formed by a down-draw method (such as overflow down-draw method). The ear portions (portions with a thickness greater than other portions) formed at both ends in the width direction during the forming are cut off and removed. The glass ribbon 2 has: one end portion 2c in the width direction, which includes a first position PS1 described later; the other end portion 2d in the width direction, which includes a second position PS2 described later; and a central portion 2e, which includes a center position PS3 in the width direction and is located between the two end portions 2c and 2d.

[0051] Figure 2The first length L1, the second length L2, and the third length L3 shown are lengths obtained by measuring the length of the glass ribbon 2 from the leading end 2a to the trailing end 2b along the surface 2f along the first position PS1, the second position PS2, and the center position PS3 in the width direction, respectively. By measuring each length L1 to L3 along the surface 2f in this way, the influence of the unevenness of the surface 2f is reflected in the measurement results of the lengths L1 to L3, and the number and size of the unevenness are reflected as the length of the measurement results.

[0052] The first position PS1 and the second position PS2 are positions separated 200 mm inward from one side edge 2g and the other side edge 2h in the width direction of the glass ribbon 2, respectively. In the present embodiment, each of the lengths L1 to L3 measured along the first position PS1, the second position PS2, and the center position PS3 in the width direction is measured using a roll encoder 5 described later.

[0053] When measuring the above first length L1 to third length L3, for each 100 m length measured along the center position PS3 in the width direction, the dimensional difference between the length measured along the first position PS1 and the length measured along the second position PS2 is 37 mm or less. That is, based on the length measured along the center position PS3 in the width direction, when the glass ribbon 2 is divided into a plurality of sections each having a length of 100 m, in each section, the difference between the length measured along the first position PS1 and the length measured along the second position PS2 is within 37 mm. The above dimensional difference is preferably 25 mm or less, more preferably 15 mm or less. The above dimensional difference is, for example, 0 mm or more, and from the viewpoint of suppressing an increase in manufacturing cost, it is 10 mm or more.

[0054] <Measurement method of the first length to the third length>

[0055] Hereinafter, the measurement method of the first length L1 to the third length L3 will be described.

[0056] As a first method for measuring the first length L1 to the third length L3, the following method can be cited. That is, it is a method in which, after the glass ribbon 2 formed by the down-draw method is transported along the transport path while disconnecting and removing unnecessary portions (including the ear portions) existing at both ends in its width direction, when the glass ribbon 2 is wound at the downstream end of the transport path to produce the glass roll 1, the lengths L1 to L3 are measured on the transport path.

[0057] Further, as a second method for measuring the first length L1 to the third length L3, a so-called roll to roll method can be cited. That is, it is as follows: The above-mentioned core 4 is set as the first core, and after the glass tape 2 constituting the glass roll 1 is unrolled from the first core and transported while measuring the respective lengths L1 to L3 on its transport path, the glass tape 2 is wound around a second winding core different from the first core to become a glass roll again.

[0058] Here, a specific example in the case of performing measurement using the above-mentioned first method or second method is cited. In this specific example, as Figure 3 and Figures 4a to 4c shown, for the glass tape 2 transported in a flat attitude on a transport mechanism (not shown) such as a belt conveyor or a roller conveyor, a roller encoder 5 in contact with its surface 2f is used to measure the first length L1 to the third length L3.

[0059] The roller 5a provided in the roller encoder 5 can rotate without slipping by friction with the surface 2f in a state of always being in contact with the surface 2f of the glass tape 2. And the roller 5a measures the respective lengths L1 to L3 based on the distance rolled on the surface 2f.

[0060] As Figure 3 shown, three roller encoders 5 are arranged as measuring devices for the first length L1, the second length L2, and the third length L3 respectively measured along the first position PS1, the second position PS2, and the center position PS3 in the width direction. The three rollers 5a provided in the three roller encoders 5 are arranged along the width direction of the glass tape 2 and are located at the same location on the transport path of the glass tape 2.

[0061] As Figures 4a to 4c shown, the roller 5a provided in each roller encoder 5 can move in the thickness direction of the glass tape 2 following the unevenness of the surface 2f. It should be noted that in Figures 4a to 4c the unevenness of the surface 2f is exaggerated. When the roller 5a crosses the unevenness along with the transport of the glass tape 2, the roller 5a moves upward from the position shown by the double-dot chain line in Figure 4b to the position shown by the solid line. In addition, the roller 5a is structured to always apply a certain load (a load acting in the thickness direction of the glass tape 2) to the glass tape 2. The magnitude of the load is such that it can maintain the state where the roller 5a is always in contact with the surface 2f and does not flatten the unevenness by crushing it.

[0062] Here, as a modification example of the present embodiment, the magnitude of the load applied by the roller 5a to the glass ribbon 2 may also be set to the magnitude of the degree to which the unevenness is flattened by the roller 5a being flattened. Even in this case, the first length L1, the second length L2, and the third length L3 can be measured without problems.

[0063] When the rollers 5a provided in the respective roller encoders 5 respectively roll from the leading end 2a to the trailing end 2b along the surface 2f of the glass ribbon 2 at the first position PS1, the second position PS2, and the center position PS3 in the width direction and end, the measurement of the above-mentioned respective lengths L1 to L3 is completed.

[0064] <Method for manufacturing a glass article>

[0065] Hereinafter, a method for manufacturing the above-mentioned glass roll 1, which is an example of a glass article, will be described. In this manufacturing method, as the main process for manufacturing the glass roll 1, the overflow down-draw method is used to form the glass ribbon 2.

[0066] As Figures 5 to 7 shown, this manufacturing method includes: a forming step P1 of forming the glass ribbon 2 from the molten glass 6; a conveying step P2 (longitudinal conveying step) of conveying the glass ribbon 2 in a temperature region of 300 °C or higher along a conveying path; a conveying direction conversion step P3 of conveying the glass ribbon 2 along a bent conveying track so as to convert its conveying direction from longitudinal to transverse; a transverse conveying step P4 of conveying the glass ribbon 2 whose conveying direction has been converted in the transverse direction; a cutting step P5 of cutting off unnecessary portions 2x existing at both ends in the width direction of the glass ribbon 2 conveyed in the transverse direction and disconnecting them from the effective portion 2y; and a winding step P6 of winding the glass ribbon 2 composed only of the effective portion 2y with the unnecessary portions 2x disconnected in a roll shape at the downstream end of the conveying path to form the glass roll 1.

[0067] In the execution of the forming step P1, a forming body 7 for the overflow down-draw method having a wedge-shaped cross-sectional shape is used.

[0068] The forming body 7 has: a groove 7a formed at the top for the molten glass 6 to flow in; a pair of side faces 7b, 7b for guiding the molten glass 6 that has overflowed from the groove 7a to both sides to flow down respectively; and a lower end portion 7c for fusing and integrating the molten glass 6 flowing down along the side faces 7b, 7b. And the glass ribbon 2 is continuously formed from the molten glass 6 fused and integrated at the lower end portion 7c by the forming body 7.

[0069] The conveying process P2 includes a cooling process P2a of cooling one end 2s and the other end 2t of the glass ribbon 2 while conveying the glass ribbon 2, and an annealing process P2b of annealing the glass ribbon 2 that has undergone the cooling process P2a while conveying it. Here, in the annealing process P2b, when the viscosity of the glass ribbon 2 is set to η, the value of logη using the common logarithm becomes 14.5 Poise (1.45 Pa·s) or less. It should be noted that the "one end 2s" includes the unnecessary part 2x that is later disconnected from the effective part 2y and one end 2c in the width direction of the effective part 2y. Similarly, the "other end 2t" includes the unnecessary part 2x that is later disconnected from the effective part 2y and the other end 2d in the width direction of the effective part 2y.

[0070] During the execution of the conveying process P2, rolls arranged in multiple upper and lower stages are used. Among these rolls, in order from the upper stage side, there are a cooling roll 8, an annealing roll 9, and a support roll 10. Each of the rolls 8, 9, 10 is configured by a pair of rolls that sandwich the glass ribbon 2 from both the front and back sides and are respectively corresponding to one end 2s and the other end 2t in the width direction of the glass ribbon 2. Here, in the following description, among each of the rolls 8, 9, 10, the roll corresponding to the one end 2s is denoted as the "first roll 8a, 9a, 10a", and the roll corresponding to the other end 2t is denoted as the "second roll 8b, 9b, 10b". It should be noted that in this embodiment, there is one stage of cooling roll 8, six stages of annealing roll 9, and one stage of support roll 10, but the number of stages of each of the rolls 8, 9, 10 can be appropriately increased or decreased.

[0071] The cooling roll 8 is a roll for executing the cooling process P2a, and has a function of respectively contacting and cooling one end 2s and the other end 2t of the glass ribbon 2 directly below the formed body 7 and suppressing the shrinkage in the width direction of the glass ribbon 2. The annealing roll 9 has a function of guiding the glass ribbon 2 that has been annealed to a temperature below, for example, the strain point downward in an annealing furnace (not shown) for executing the annealing process P2b. The support roll 10 has a function of supporting the glass ribbon 2 during the process of reducing the temperature to near room temperature in a cooling chamber (not shown) provided below the annealing furnace.

[0072] Here, the annealing roll 9 will be described in detail. As described above, the annealing roll 9 is arranged in six upper and lower stages. Each of the annealing rolls 9 respectively pulls one end 2s and the other end 2t of the glass ribbon 2 by the first roll 9a and the second roll 9b. The amount of elongation (elongation along the length direction of the glass ribbon 2) of one end 2s and the other end 2t of the glass ribbon 2 conveyed in the annealing furnace is increased or decreased by the magnitude of the pulling force (speed) of these first roll 9a and second roll 9b.

[0073] The glass ribbon 2 is taken as an example and its thickness is formed to be 300 μm or less. It should be noted that it is preferably formed to have a thickness of 200 μm or less, more preferably 100 μm or less, and most preferably 50 μm or less. The unnecessary portion 2x of the glass ribbon 2 includes ears with a larger thickness compared to other parts. Here, in the present embodiment, the glass ribbon 2 is formed by the overflow down-draw method, but as a modified example of the present embodiment, the glass ribbon 2 can also be formed by the slot down-draw method, the re-draw method, etc.

[0074] During the execution of the transfer direction conversion process P3, a roller conveyor 11 composed of a plurality of rollers arranged along the bent transfer track is used. And the transfer direction of the glass ribbon 2 is smoothly converted from the longitudinal direction to the lateral direction by the roller conveyor 11.

[0075] During the execution of the horizontal transfer process P4, conveyors 12 to 14 are used. And the glass ribbon 2 is transferred horizontally by these conveyors 12, 13, and 14.

[0076] During the execution of the cutting process P5, a laser cutter 15 that cuts the glass ribbon 2 by the laser cutting method is used. And laser 15a is irradiated from the laser cutter 15 along the boundary lines B between the effective portion 2y and the two unnecessary portions 2x, 2x in the glass ribbon 2, and the two unnecessary portions 2x, 2x are respectively cut off from the effective portion 2y. It should be noted that the two cut-off unnecessary portions 2x, 2x fall downward from the conveyor 14 and are discarded.

[0077] During the execution of the winding process P6, a core 4 and a sheet roll 16 formed by winding a strip-shaped protective sheet 3 are used. And the glass ribbon 2 composed only of the effective portion 2y that arrives at the core 4 along with the transfer is wound around the core 4 in a state of being overlapped with the strip-shaped protective sheet 3 supplied from the sheet roll 16.

[0078] In this manufacturing method, in addition to the above-mentioned respective processes P1 to P6, a measurement process P7 and an adjustment process P8 are also executed. It should be noted that the two processes P7 and P8 are not always executed, but are intermittently executed at a prescribed time interval or are executed after the replacement of the manufacturing equipment (such as the replacement of the annealing roller 9, etc.).

[0079] In the measurement process P7, for the measurement target section S, which is an interval along the length direction of the glass ribbon 2, the lengths from the leading end Sa to the trailing end Sb of the target section S are measured respectively along one end 2c, the other end 2d, and the central section 2e (here, the center position in the width direction) of the effective section 2y, and the first measurement length LL1 to the third measurement length LL3 are obtained. As a method of the measurement process P7, for example, the first or second method for measuring the first length L1 to the third length L3 described above can be adopted. In the present embodiment, the first method described above is adopted.

[0080] Here, the length of the measurement target section S (the length along the length direction of the glass ribbon 2) can be any length, but it is preferably 20 m or more in order to accurately grasp the balance of the elongation amounts between the two end sections 2s and 2t of the glass ribbon 2. It should be noted that the "length of the measurement target section S" as described here refers to the length along the center position in the width direction of the glass ribbon 2 (effective section 2y). Therefore, in the present embodiment, the third measurement length LL3 becomes the length of the measurement target section S.

[0081] In multiple stages of the six-stage annealing roller 9, a speed difference is provided between the first roller 9a and the second roller 9b (hereinafter, each of these multiple stages may be referred to as a "stage where a speed difference is provided"). In the adjustment process P8, when a speed difference is provided between the first roller 9a and the second roller 9b based on the dimensional difference between the first measurement length LL1 and the second measurement length LL2, the magnitude of the speed difference (for example, the difference in peripheral speed) is adjusted. Thereby, the balance of the traction force between the two rollers 9a and 9b is changed, and the elongation amounts of the one end section 2s and the other end section 2t of the glass ribbon 2 are equalized. It should be noted that the two rollers 9a and 9b are connected to different drive sources (for example, motors), and the speed V1 of the first roller 9a and the speed V2 of the second roller 9b can be independently changed. Here, in the multiple-stage annealing roller 9, the method of providing a speed difference between multiple stages may be the same or different.

[0082] Hereinafter, the adjustment process P8 will be described in detail. Here, an example where the first measurement length LL1 is longer than the second measurement length LL2 based on the result of the measurement process P7 is given. It should be noted that between the first measurement length LL1 and the second measurement length LL2, neither specific one is always longer, but sometimes the longer side alternates. As an example, it may alternate when the annealing roller 9 is replaced or the like.

[0083] In the present embodiment, when the length of the measurement target section S is set to 100 m (i.e., the third measurement length LL3 is 100 m), and the dimensional difference between the first measurement length LL1 and the second measurement length LL2 exceeds 37 mm set as a threshold value, the adjustment process P8 is executed. Note that the value set as the threshold value can be arbitrarily set according to, for example, the required quality of the glass ribbon 2 and the breakage condition of the glass ribbon.

[0084] Of the one end portion 2s and the other end portion 2t of the glass ribbon 2, the end portion on the side with the relatively longer measured length measured according to the result of the measurement process P7 is set as the long side end portion, and the end portion on the side with the relatively shorter measured length measured according to the result of the measurement process P7 is set as the short side end portion. At this time, in the present embodiment, the one end portion 2s becomes the long side end portion and the other end portion 2t becomes the short side end portion. That is, at the moment before the execution of the adjustment process P8, in the glass ribbon 2, the extension amount of the one end portion 2s is in a state where it is larger than the extension amount of the other end portion 2t.

[0085] In the adjustment process P8, the speed V1 of the first roller 9a on the side corresponding to the long side end portion (one end portion 2s) of the first roller 9a and the second roller 9b in the section where the speed difference is set is reduced. On the other hand, the speed V2 of the second roller 9b on the side corresponding to the short side end portion (the other end portion 2t) is increased. Thereby, the extension amount of the one end portion 2s is reduced, and the extension amount of the other end portion 2t is increased. In this way, the extension amounts of the both end portions 2s and 2t are equalized. Note that, in the present embodiment, at the moment before the execution of the adjustment process P8, the speed V1 of the first roller 9a and the speed V2 of the second roller 9b are the same speed, and the speed difference between the two rollers 9a and 9b becomes zero. On the other hand, in the cooling roller 8, the support roller 10, and the roller conveyor 11, before and after the execution of the adjustment process P8, no speed difference is set between the two rollers corresponding to the one end portion 2s and the other end portion 2t, and they are at the same speed.

[0086] Here, as a modification example of the present embodiment, it may be that when equalizing the extension amounts of the both end portions 2s and 2t, while maintaining the speed V1 of the first roller 9a in the section where the speed difference is set at the speed before the adjustment process P8, the speed V2 of the second roller 9b is increased. Moreover, as another modification example, it may be that while maintaining the speed V2 of the second roller 9b at the speed before the adjustment process P8, the speed V1 of the first roller 9a is reduced. Note that in both the present embodiment and the modification examples of the present embodiment, it is preferably that the speed of the relatively faster one of the speed V1 and the speed V2 becomes 100.1% or less based on the speed of the relatively slower one.

[0087] Further, as a modification of this embodiment, it is also possible to provide a speed difference between the first roller 9a and the second roller 9b in a part (e.g., only one section) of the above-described multi-stage annealing roller 9. Moreover, the first roller and the second roller with the speed difference provided therebetween may be used in the conveying process P2 (longitudinal conveying process). Alternatively, a speed difference may be provided between the first roller 8a and the second roller 8b in the cooling roller 8 (in the cooling process P2a in addition to the annealing process P2b) or instead of the annealing roller 9 (in the cooling process P2a instead of the annealing process P2b). In these cases, from the viewpoint of making the elongation amounts of the both end portions 2s and 2t more uniform, it is preferable to provide the speed difference after the second section excluding the uppermost section on the basis that the cooling roller 8 is arranged in two or more upper and lower stages. In addition, in any case, from the viewpoint of making the elongation amounts of the both end portions 2s and 2t more uniform, it is preferable that the first roller and the second roller with the speed difference provided therebetween be arranged in two or more stages, and more preferably in three or more stages. Moreover, in any case, it is also possible to provide a speed difference between the first roller 10a and the second roller 10b in the support roller 10 arranged in the cooling chamber in addition to the annealing roller 9 and the cooling roller 8.

[0088] Here, as a further modification of this embodiment, it is also possible to adopt a method of providing a speed difference between the first roller and the second roller by focusing on the temperature region and viscosity region of the glass ribbon 2 in the conveying process P2. For example, in the case of focusing on the temperature region, it is also possible to provide a speed difference between the first roller and the second roller in the section that contacts the region where the glass ribbon 2 is in a temperature region of 300 °C or higher during the execution of the conveying process P2 among the rollers 8, 9, and 10 arranged in multiple upper and lower stages. From the viewpoint of efficiently equalizing the elongation amounts of the both end portions 2s and 2t, the above temperature region is preferably 450 °C or higher, and more preferably 600 °C or higher. On the other hand, the upper limit of the above temperature region is not particularly limited as long as the glass ribbon 2 can be formed. However, as described above, it is preferable to provide the speed difference after the second section excluding the uppermost section.

[0089] On the other hand, in the case of focusing on the viscosity region, it is also possible to provide a speed difference between the first roller and the second roller in the section that contacts the region where the viscosity of the glass ribbon 2 is set to η and the value of log η is 28.1 Poise or less using the common logarithm among the rollers 8, 9, and 10 arranged in multiple upper and lower stages. From the viewpoint of efficiently equalizing the elongation amounts of the both end portions 2s and 2t, the above viscosity region is preferably 22.0 Poise or less, and more preferably 17.0 Poise or less. On the other hand, the upper limit of the above viscosity region is not particularly limited as long as the glass ribbon 2 can be formed. However, as described above, it is preferable to provide the speed difference after the second section excluding the uppermost section.

[0090] After performing the adjustment process P8, the measurement process P7 is performed again with a section different from the above-described measurement target section S as a new measurement target section S. It should be noted that the "new measurement target section S" refers to a section along the length direction of the formed glass ribbon 2 after the execution of the adjustment process P8.

[0091] If the result of the re-performed measurement process P7 is that the dimensional difference between the first measurement length LL1 and the second measurement length LL2 is 37 mm or less, it is regarded that the elongation amounts of one end portion 2s and the other end portion 2t of the glass ribbon 2 are equalized. And the speed V1 of the first roller 9a and the speed V2 of the second roller 9b of the section where the speed difference is set are maintained at the speeds after the adjustment process P8. Moreover, in the state after the adjustment process P8, the effective portion 2y in the formed glass ribbon 2 is wound around the winding core 4.

[0092] On the other hand, if the result of the re-performed measurement process P7 is that the dimensional difference between the first measurement length LL1 and the second measurement length LL2 still exceeds 37 mm, the two processes P7 and P8, namely the measurement process P7 and the adjustment process P8, are alternately performed while changing the measurement target section S to a new section every time the measurement process P7 is performed until the dimensional difference between the first measurement length LL1 and the second measurement length LL2 is 37 mm or less.

[0093] It should be noted that in the measurement process P7 performed one or more times, the surface 2f of the section that becomes the measurement target section S in the effective portion 2y may be contaminated due to contact with the roller 5a provided in the roller encoder 5. Therefore, it may also be discarded after disconnecting from the section that becomes the winding target in the effective portion 2y (the section actually wound around the winding core 4). Moreover, regarding the section formed in the effective portion 2y before the dimensional difference between the first measurement length LL1 and the second measurement length LL2 becomes 37 mm or less, it may also be discarded as a defective product after disconnecting from the section that becomes the winding target in the effective portion 2y.

[0094] According to the manufacturing method of the glass article described above, the glass ribbon 2 (the glass ribbon 2 composed only of the effective portion 2y) with the elongation amounts of one end portion 2c and the other end portion 2d equalized can be wound around the winding core 4. Therefore, it is possible to obtain the glass roll 1 that does not have defects such as wrinkles or torsion occurring on one side in the width direction due to the dimensional difference between the two end portions 2c and 2d.

[0095] Here, in the above-described embodiment, the glass roll 1 is manufactured as a glass article, but it is not limited thereto. For example, it may be a method of manufacturing a glass plate as a glass article by cutting the glass ribbon 2 that has undergone the conveying process P2 along the width direction while continuing to convey it longitudinally and cutting it out from the glass ribbon 2, and performing the measurement process P7 and the adjustment process P8 on the glass ribbon 2 before cutting as the object. The thickness of the glass plate is, for example, 200 μm to 2000 μm.

[0096] In addition, in the above-described embodiment, the measurement process P7 and the adjustment process P8 are provided, but it is not limited thereto. For example, the measurement process P7 and the adjustment process P8 may be omitted, and based on the past operation results, the first roller 9a and the second roller 9b with a set speed difference are arranged and their speed difference is set.

[0097] Examples

[0098] In order to verify the effects of the present invention, in the same manner as the above-described embodiment, the glass ribbon 2 was formed when manufacturing the glass roll 1, and a speed difference was set between the first roller 9a and the second roller 9b in a part of the six annealing rollers 9 by the adjustment process. Then, it was confirmed whether torsion occurred in the glass ribbon 2. The conditions of Examples 1 to 3 and the comparative example are as shown in [Table 1] below. Here, each item in [Table 1] will be described.

[0099] "Number of annealing roller segments" indicates how many upper and lower segments of the annealing roller 9 with a speed difference set between the first roller 9a and the second roller 9b exist.

[0100] "Speed ratio" indicates what percentage of the speed the roller with a relatively faster speed between the first roller 9a and the second roller 9b has with respect to the roller with a relatively slower speed in the annealing roller 9 with a speed difference set.

[0101] "Glass viscosity" refers to the viscosity represented by the value of logη using the common logarithm when the viscosity of the glass ribbon 2 in the region where the annealing roller 9 with a speed difference set is arranged is set to η.

[0102] "Dimension difference at the edge portion" indicates the dimension difference between the first measurement length LL1 and the second measurement length LL2 per 100 m length of the third measurement length LL3 when measuring the first measurement length LL1 to the third measurement length LL3 in the measurement process P7.

[0103] [Table 1]

[0104] Comparative Example Example 1 Example 2 Example 3 Number of annealing roller segments 0 1 2 3 Speed ratio [%] - 100.1 100.05 100.03 Glass viscosity [poise] - 11.0 11.0～11.6 10.6～11.6 Dimension difference at the edge [converted to mm / 100m] 40～80 11～34 10～26 4～12 Generation of torsion × Δ ○ ○

[0105] As a result of the verification, in the comparative example, since torsion was constantly generated in the glass ribbon 2, it was judged as "×". In Example 1, the torsion was reduced to an allowable range, so it was judged as "Δ". In Examples 2 and 3, generation of torsion was not confirmed at all, so it was judged as "○". It is presumed that such a result was obtained because a speed difference was provided between the first roller 9a and the second roller 9b in Examples 1 to 3, thereby equalizing the elongation amounts between one end portion 2s and the other end portion 2t in the glass ribbon 2.

[0106] Explanation of Reference Numerals

[0107] 1 Glass coil

[0108] 2 Glass ribbon

[0109] 2s One end portion

[0110] 2t The other end portion

[0111] 2g One side edge

[0112] 2h One side edge

[0113] 6 Molten glass

[0114] 8a First roller

[0115] 8b Second roller

[0116] 9a First roller

[0117] 9b Second roller

[0118] 10a First roller

[0119] 10b Second roller

[0120] L1 First length

[0121] L2 Second length

[0122] L3 Third length

[0123] LL1 First measured length

[0124] LL2 Second measured length

[0125] P1 Generation process

[0126] P2 Forming process

[0127] P2a Cooling process

[0128] P2b Annealing process

[0129] P3 Handling direction changing process

[0130] P4 Horizontal handling process

[0131] P6 Winding Process

[0132] P7 Measurement Process

[0133] P8 Adjustment Process

[0134] PS1 First Position

[0135] PS2 Second Position

[0136] PS3 Center Position in Width Direction

[0137] S Measurement Object Interval

[0138] Sa Leading End

[0139] Sb Trailing End

[0140] V1 Speed of the First Roller

[0141] V2 Speed of the Second Roller.

Claims

1. A method for manufacturing a glass article, comprising: a forming step of forming a glass ribbon from molten glass; and a conveying step of conveying the glass ribbon along a conveying path, wherein the method for manufacturing the glass article is characterized in that in the conveying step, for the glass ribbon in a temperature region of 300 °C or higher, a first roller and a second roller are arranged to respectively contact and convey one end portion and the other end portion in the width direction of the glass ribbon, and a speed difference is set between the first roller and the second roller; the method for manufacturing the glass article further comprises: a measuring step of measuring the lengths from the leading end portion to the trailing end portion of a measurement target section, which is an interval along the length direction of the glass ribbon, along one end portion and the other end portion of the glass ribbon respectively, and obtaining a first measured length and a second measured length; and an adjusting step of adjusting the speed difference between the first roller and the second roller based on the dimensional difference between the first measured length and the second measured length; the leading end portion and the trailing end portion of the measurement target section extend in a direction orthogonal to the conveying direction of the glass ribbon; through the adjusting step, the extension amounts of one end portion and the other end portion along the length direction of the glass ribbon are adjusted.

2. The method for manufacturing a glass article according to claim 1, wherein when one end portion of the glass ribbon, which has a relatively long measured length according to the result of the measuring step, is set as the long side end portion, and the other end portion of the glass ribbon, which has a relatively short measured length according to the result of the measuring step, is set as the short side end portion, in the adjusting step, the speed of the roller on the side corresponding to the long side end portion among the first roller and the second roller is slowed down, and the speed of the roller on the side corresponding to the short side end portion among the first roller and the second roller is increased.

3. The method for manufacturing a glass article according to claim 1 or 2, wherein the conveying step includes a cooling step of cooling one end portion and the other end portion of the glass ribbon while conveying the glass ribbon, and an annealing step of annealing the glass ribbon after the cooling step while conveying it, the first roller and the second roller are used in at least one of the cooling step and the annealing step.

4. The method for manufacturing a glass article according to claim 1 or 2, wherein the first roller and the second roller are grouped as a set, and multiple sets are arranged along the conveying path.

5. The method for manufacturing a glass article according to claim 1 or 2, wherein as the first roller and the second roller, a pair of rollers that sandwich the glass ribbon from both sides of the front and back are respectively used.

6. The method for manufacturing a glass article according to claim 1 or 2, wherein the glass ribbon is formed by the down-draw method.

7. The method for manufacturing a glass article according to claim 1 or 2, wherein The method for manufacturing the glass article further includes a winding step of winding the glass ribbon in a roll shape at the downstream end of the conveying path to form a glass roll.

8. A method for manufacturing a glass article, comprising: a forming step of forming a glass ribbon by the down-draw method; a longitudinal conveying step of conveying the glass ribbon in the longitudinal direction; a conveying direction changing step of conveying the glass ribbon that has undergone the longitudinal conveying step along a curved conveying track, thereby changing the conveying direction of the glass ribbon from the longitudinal direction to the lateral direction; and a lateral conveying step of conveying the glass ribbon whose conveying direction has been changed in the lateral direction, The method for manufacturing the glass article is characterized in that in the longitudinal conveying step, a first roller and a second roller that are respectively in contact with and convey one end portion and the other end portion in the width direction of the glass ribbon are arranged, and a speed difference is provided between the first roller and the second roller, The method for manufacturing the glass article further includes: a measuring step of measuring the lengths from the leading end portion to the trailing end portion of a measurement target section, which is an interval in the length direction of the glass ribbon, along the one end portion and the other end portion of the glass ribbon, respectively, to obtain a first measurement length and a second measurement length; and an adjusting step of adjusting the speed difference between the first roller and the second roller based on the dimensional difference between the first measurement length and the second measurement length, the leading end portion and the trailing end portion of the measurement target section extend in a direction orthogonal to the conveying direction of the glass ribbon, through the adjusting step, the extension amounts of the one end portion and the other end portion in the length direction of the glass ribbon are adjusted.

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