Glass plate manufacturing method and glass raw plate package

Abstract

To suppress harm caused by glass powder generated in a plurality of cutting steps to improve the quality of a glass plate obtained from a glass original plate as a product.SOLUTION: A method for manufacturing a glass plate comprises: the molding step A of molding a glass ribbon GR; the first cutting step B of cutting a glass original plate G1 by scribe cutting in the width direction from the molded glass ribbon GR; the second cutting step C of holding the glass original plate G1 subjected to the first cutting step B in the vertical posture to remove both ends of the glass original plate G1 in the width direction by scribe cutting in the vertical direction; and the step of cutting a glass plate g from the glass original plate G2 subjected to the second cutting step C. A scribe line is formed on non-guaranteed surface 3 of the glass original plate in at least one of the first cutting step B and the second cutting step C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a glass plate, which includes a step of scribing to obtain a glass raw plate that will become a glass plate from a glass ribbon formed by a down-draw method, and to a glass raw plate package in which the glass raw plate obtained by the scribing is packaged. [Background technology]

[0002] As is well known, techniques using downdraw methods, such as the overflow downdraw method, the slot downdraw method, and the redraw method, are widely used to manufacture glass sheets. One example of a glass sheet manufacturing process using the overflow downdraw method is shown below. The example below is a manufacturing process for a glass sheet that is suitable for use as a glass substrate or cover glass in displays such as liquid crystal displays and organic EL displays.

[0003] First, in this type of manufacturing process, as disclosed in Patent Document 1, a forming step of forming a glass ribbon and a first cutting step (X-cutting step) of cutting out a glass base plate from the formed glass ribbon by scribing are carried out.

[0004] In the forming process, molten glass is supplied to an overflow groove provided at the top of a wedge-shaped forming body and allowed to overflow. The overflowing molten glass flows down along the side surfaces of the forming body and is then fused and integrated at the lower end of the forming body. This forms a plate-shaped glass ribbon. The formed glass ribbon is then drawn downward while being clamped from both sides by pairs of rollers arranged in multiple stages above and below. The glass ribbon obtained in this way has ears formed at both widthwise ends that are thicker than the widthwise central portion.

[0005] The scribe cutting performed in the first cutting step involves forming a scribe line along the width direction on the main surface of the glass ribbon being conveyed downward, curving the area surrounding the scribe line to apply bending stress and cutting the glass ribbon along the scribe line. When performing this scribe cutting, the glass ribbon is curved so that the main surface side on which the scribe line is formed is convex.

[0006] Next, in this type of manufacturing process, as disclosed in Patent Document 2, a second cutting step (Y cutting step) is carried out to remove the edge portions formed at both widthwise ends of the above-mentioned glass original plate by scribing.

[0007] The scribe cutting performed in the second cutting step involves forming a scribe line along the longitudinal direction on the main surface of the widthwise end portion of the glass ribbon held in a vertical position, curving the area surrounding the scribe line to apply bending stress and cutting the glass ribbon along the scribe line. When performing this scribe cutting, the glass ribbon is also curved so that the main surface side on which the scribe line is formed is convex. This scribe cutting is performed separately on one widthwise end portion and the other widthwise end portion of the glass raw sheet. As a result, a glass raw sheet without ear portions at both widthwise end portions is obtained.

[0008] Thereafter, in a predetermined post-process, a glass plate of a predetermined size is obtained from the glass original plate having no edge portions by scribing or the like. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Publication No. 2017-202958 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-226549 Summary of the Invention [Problem to be solved by the invention]

[0010] Incidentally, when scribing in the first cutting step and the second cutting step, glass powder scatters. This glass powder tends to scatter toward the main surface of the glass plate where the scribe line was formed, and a considerable amount of the scattered glass powder adheres to the main surface.

[0011] One main surface of a glass blank is a guaranteed surface, and the other main surface is a non-guaranteed surface. Here, the guaranteed surface is the surface on which elements, etc. are formed, and its surface quality is guaranteed, whereas the non-guaranteed surface is a surface whose surface quality does not need to be guaranteed to the same extent as the guaranteed surface. Therefore, if glass powder adheres to the guaranteed surface of a glass blank, the guaranteed surface may be scratched by the glass powder, or some of the glass powder may remain after cleaning, leading to a decrease in the quality of the glass sheet as a product obtained from the glass blank.

[0012] From the above viewpoints, an object of the present invention is to suppress the adverse effects of glass powder generated in the first cutting step of cutting out a glass raw sheet from a glass ribbon formed by the down-draw method and the second cutting step of removing both widthwise end portions of the glass raw sheet, thereby improving the quality of the glass sheet as a product obtained from the glass raw sheet. [Means for solving the problem]

[0013] A first aspect of the present invention, which has been invented to solve the above-mentioned problems, is a method for manufacturing a glass plate, comprising: a forming step of forming a glass ribbon by a down-draw method; a first cutting step of cutting out a glass raw plate from the glass ribbon formed in the forming step by scribing along the width direction; and a second cutting step of holding the glass raw plate that has undergone the first cutting step in a vertical position and removing both widthwise end portions of the glass raw plate by scribing along the vertical direction, and obtaining a glass plate from the glass raw plate that has undergone the second cutting step, characterized in that in at least one of the first cutting step and the second cutting step, a scribe line is formed on the non-guaranteed surface of the glass raw plate, which is one of the main surfaces of the glass raw plate, that is, the guaranteed surface, and the other main surface of the glass raw plate.

[0014] According to this configuration, a scribe line is formed on the non-guaranteed side of the glass blank in at least one of the first cutting step and the second cutting step, which suppresses adhesion of scattered glass powder to the guaranteed side when scribing in these steps. This reduces scratches on the guaranteed side caused by glass powder and also reduces the possibility that some of the glass powder adhering to the guaranteed side remains unremoved in the cleaning step. As a result, the quality of the glass blank obtained as a product from the glass blank can be improved.

[0015] In this configuration, a scribe line may be formed on the non-guaranteed surface of the glass original plate in both the first cutting step and the second cutting step.

[0016] This makes it possible to reliably prevent glass powder from adhering to the protection surface of the glass plate when scribing is performed in the two cutting steps, thereby achieving a significant improvement in the quality of the glass plate as a product.

[0017] In the above configuration, the method may further include a storage step of stacking the glass original plate and the protective sheet that have undergone the second cutting step alternately in a vertical position on a pallet for storage, and in the storage step, the guaranteed surface of the glass original plate may be supported by a back support portion provided on the pallet.

[0018] In this way, the guaranteed side of the glass blank is positioned on the rear support side of the pallet, and the non-guaranteed side is positioned on the opposite side. Here, when the glass blanks and protective sheets are stacked one after another on the pallet, the corner between the guaranteed side and its lower end surface (cut surface) of the glass blank to be loaded may come into contact with the non-guaranteed side of the front-most loaded glass blank (see Figure 8, described below). While this contact could potentially scratch the non-guaranteed side of the loaded glass blank, the guaranteed side is reliably protected without any risk of scratching. Furthermore, if scribe marks are present on the non-guaranteed side of the lower end surface of the glass blank to be loaded, even if the above-mentioned contact occurs, the corner where the scribe marks are formed will not come into contact. Here, the scribe marks are marks left as scribe lines on the cut surface of the glass blank. Because these scribe marks have numerous cracks, if they come into contact with the non-guaranteed side of the glass blank, glass powder may be generated from the scribe marks or breakage may occur starting from the scribe marks. However, if the corners where the scribe marks are formed do not come into contact as described above, such a problem will not occur.

[0019] In this configuration, the storing step may include a transporting step of transporting the glass original plates and the protective sheets stacked on the pallet.

[0020] This effectively protects the glass blanks when the glass blanks and protective sheets stacked on the pallet are transported (for example, to another factory or within the same factory). During transport, the lower end surface of the glass blank may shift away from the rear support due to shaking, vibration, or the like (a shift that reduces the angle of inclination of the glass blank relative to the horizontal plane) (see FIG. 10 , described below). When this shift occurs, friction occurs at the corner between the guaranteed side of the glass blank and its lower end surface, and the pressure acting on the corner increases. If scribe marks are present on the non-guaranteed side of the lower end surface of the glass blank, the friction and increased pressure acting on the corner where the scribe marks are formed do not occur, preventing the generation of glass powder and breakage.

[0021] In these configurations, the protective sheet may be a foamed resin sheet.

[0022] In this way, even if glass powder adheres to the guaranteed or non-guaranteed side of the glass blanks loaded on the pallet, the force pressing the glass powder against the glass blanks is reduced by the deformation of the foamed resin sheet, thereby reducing the risk of the glass blanks being scratched or broken by the glass powder during the storage process.

[0023] The above-described configuration may further include a third cutting step of scribing and cutting out a glass plate from the glass plate that has undergone the storage step, and a cleaning step of cleaning the glass plate that has undergone the third cutting step, wherein in the third cutting step, the glass plate is placed flat and the non-guaranteed surface of the glass plate is supported from below, and a scribe line is formed on the guaranteed surface of the glass plate; and in the cleaning step, the glass plate is placed flat and the non-guaranteed surface of the glass plate is supported from below, and the glass plate is cleaned.

[0024] In this way, during the third cutting step and the cleaning step, defects such as contact marks and dirt may occur on the non-guaranteed side of the flat-laid glass sheet and the glass sheet due to contact with the support member supporting it from below, but such defects do not occur on the guaranteed side, and therefore the guaranteed side is reliably protected. Furthermore, during the third cutting step, glass powder due to scribing adheres to the guaranteed side of the cut glass sheet. However, by removing the glass powder adhered to the guaranteed side of the glass sheet as quickly as possible in the subsequent cleaning step, scratches on the guaranteed side due to the glass powder can be prevented. Furthermore, because scribe marks are formed on the non-guaranteed side (lower side) of the edge of the glass sheet, there is a risk that the scribe marks may come into contact with the supporting member below. However, if the glass sheet is placed on the above-mentioned protective sheet (e.g., a foam resin sheet), its cushioning and elasticity reduce scratches and breakage caused by glass powder. On the other hand, with respect to the glass plate, the scribe marks are formed on the secure surface side (upper side) of the edge face, so that the scribe marks cannot come into contact with the supporting member below.

[0025] In this configuration, a processing step of processing an edge surface of the glass plate with a processing tool may be further provided between the third cutting step and the cleaning step.

[0026] Here, the scribe marks on the guaranteed side of the edge of the glass plate have better linearity than the portions on the non-guaranteed side of the edge. Therefore, even if the edge of the glass plate is subjected to processing such as cutting or polishing, chipping or cracking is unlikely to occur on the guaranteed side of the glass plate. Moreover, this processing step eliminates the scribe marks on the glass plate, preventing the generation of glass powder and breakage.

[0027] A second aspect of the present invention, which has been devised to solve the above-mentioned problems, is a glass original sheet package comprising a glass original sheet laminate in which glass original sheets and protective sheets are alternately laminated in a vertical position, and a pallet on which the glass original sheet laminate is loaded, characterized in that both the vertical end face and the horizontal end face of the glass original sheet are cut surfaces produced by scribe cutting, and at least one of the end faces has a scribe mark on the non-guaranteed surface side of the glass original sheet, which is one of the main surfaces, a guaranteed surface, and the other main surface, a non-guaranteed surface.

[0028] According to this configuration, at least one of the longitudinal end face and the lateral end face of the glass blank sheet included in the package has a scribe mark on the non-guaranteed side, thereby suppressing adhesion of glass powder to the guaranteed side of the glass blank sheet. Furthermore, even if glass powder is generated from the scribe mark while the glass blank sheet is stored in the package, problems caused by the glass powder on the guaranteed side can be suppressed.

[0029] In this configuration, both the longitudinal end face and the lateral end face of the glass plate may have scribe marks on the non-guaranteed surface side.

[0030] This reliably prevents glass powder from adhering to the guaranteed surface of the glass blank, and also reliably prevents glass powder generated from the scribe marks from causing problems on the guaranteed surface while the glass blank is stored in a package.

[0031] In these configurations, the pallet may include a rear support portion that supports the rear surface of the glass original plate laminate and a bottom support portion that supports the bottom surface of the glass original plate laminate, and the guaranteed surface of the glass original plate may be located on the rear support portion side.

[0032] In this way, when the glass original sheets and protective sheets are stacked one after another on the pallet, even if the corner between the guaranteed side of the glass original sheet to be loaded and its lower end surface (cut surface) abuts against the non-guaranteed side of the loaded glass original sheet, the guaranteed side is reliably protected. Moreover, if scribe marks are present on the non-guaranteed side of the lower end surface of the glass original sheet, even if the abutment or the like occurs, the abutment or the like will not occur at the corner where the scribe marks are formed, thereby preventing the generation of glass powder and breakage. [Effects of the Invention]

[0033] According to the present invention, the adverse effects of glass powder generated in the first cutting step of cutting out a glass raw sheet from a glass ribbon formed by the down-draw method and the second cutting step of removing both widthwise ends of the glass raw sheet are suppressed, thereby improving the quality of the glass sheet as a product obtained from the glass raw sheet. [Brief explanation of the drawings]

[0034] [Figure 1] 1 is a flowchart illustrating a method for manufacturing a glass plate according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view illustrating an example of how a forming step, a first cutting step, and a second cutting step are performed in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 3] FIG. 2 is a side view schematically illustrating a state in which a first cutting step is performed in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 4] FIG. 2 is a vertical cross-sectional side view showing an original glass plate cut out in a first cutting step in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 5] FIG. 3 is a plan view schematically showing a state in which a second cutting step is carried out in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 6] FIG. 2 is a cross-sectional plan view showing the glass plate cut out in the second cutting step in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 7] FIG. 2 is a perspective view illustrating an example of a storage step in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 8] FIG. 2 is a partially enlarged vertical cross-sectional side view illustrating an example of a storage step in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 9] 1 is a perspective view illustrating an example of a glass original sheet package according to an embodiment of the present invention. FIG. [Figure 10] FIG. 2 is a partially enlarged vertical cross-sectional side view showing a main part of a glass substrate package according to an embodiment of the present invention. [Figure 11] FIG. 2 is a perspective view illustrating an example of a state in which a posture changing step is performed in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 12] FIG. 10 is a perspective view illustrating an example of a state in which a third cutting step is performed in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 13] FIG. 2 is a perspective view illustrating an example of how a processing step, a cleaning step, an etching step, and a loading step are carried out in the glass plate manufacturing method according to the embodiment of the present invention. [Figure 14] FIG. 3 is a plan view showing a main part of the glass plate cut out in a third cutting step in the glass plate manufacturing method according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, a method for manufacturing a glass sheet and a glass original sheet package according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0036] As shown in Fig. 1, the method for manufacturing a glass plate mainly comprises a shaping step A, a first cutting step B, a second cutting step C, a storage step D, a position changing step E, a third cutting step F, a processing step G, and a cleaning step H. This method for manufacturing a glass plate relates to a glass plate used as a substrate or cover for a display such as a liquid crystal display or an organic EL display. Below, the implementation status of these steps A to H and the glass blank package produced in the storage step D will be described. In the following description, the direction of the arrow X shown in Figs. 2 to 14 is the front side, and the direction of the arrow Y is the rear side.

[0037] 2 is a perspective view illustrating an example of the implementation status of the forming step A, the first cutting step B, and the second cutting step C. The forming step A is a step of forming a glass ribbon GR from the molten glass GM. The first cutting step B is a step of cutting out a first glass original sheet G1 by scribing along the width direction from the glass ribbon GR formed in the forming step A. The second cutting step C is a step of cutting out a second glass original sheet G2 by removing both width direction end portions Ga of the first glass original sheet G1 that has undergone the first cutting step B by scribing along the vertical direction.

[0038] More specifically, in the forming step A, molten glass GM is supplied to an overflow groove 1a at the top of a wedge-shaped forming body 1 and allowed to overflow. The overflowing molten glass GM flows down along the side surfaces of the forming body 1 and is then fused and integrated at the lower end of the forming body 1. This forms a plate-shaped glass ribbon. The formed glass ribbon is then drawn downward while being sandwiched from both the front and back sides by roller pairs (not shown) arranged in multiple vertical stages. A cooling roller pair is arranged in the uppermost stage of the roller pairs arranged in multiple vertical stages. Each of the widthwise end ends Ga of the drawn glass ribbon GR has an ear portion that is thicker than the widthwise central portion. The front main surface 3 of the glass ribbon GR is a non-guaranteed surface, and the rear main surface 4 is a guaranteed surface. Here, the guaranteed surface 4 is the surface on which elements and the like of a glass sheet finally obtained from the glass ribbon GR will be formed, and is a surface for which the surface quality is guaranteed, whereas the non-guaranteed surface 3 is a surface for which the surface quality does not need to be guaranteed to the same extent as the guaranteed surface 4. The thickness of the glass ribbon GR at the center in the width direction is 1000 μm or less, preferably 700 μm or less, and the lower limit thereof is, for example, 50 μm or more.

[0039] In the first cutting step B, first, the scribe wheel 5 is pressed against the non-guaranteed surface 3 of the glass ribbon GR and moves from the position indicated by the dashed line to the position indicated by the solid line, thereby forming a scribe line S1 along the width direction of the non-guaranteed surface 3 of the glass ribbon GR. At this time, the formation area of ​​the scribe line S1 is supported from the guaranteed surface 4 side by a support member not shown in the figure, and the gripping mechanism 6 is not operating. After the scribe line S1 is formed, the scribe wheel 5 and the support member retract to a retracted position. Note that in the illustrated example, the scribe line S1 does not reach both widthwise end edges of the glass ribbon GR, but it may reach both widthwise end edges. Next, with the breaking member 2x supporting the formation area of ​​the scribe line S1 from the guaranteed surface 3 side, the gripping mechanism 6 gripping the lower end of the glass ribbon GR rotates in the direction of arrow a, thereby breaking the glass ribbon GR along the scribe line S1. This scribing and cutting by bending cuts out a first glass base plate G1 having ears at both widthwise end portions Ga. The scribe cutting is performed in a curved state so that the non-guaranteed surface 3 side of the glass ribbon GR is convex. When this scribe cutting is performed, a large amount of glass powder GF is scattered onto the non-guaranteed surface 3 side of the first glass original plate G1, as shown in Figure 3. Therefore, a considerable amount of glass powder GF adheres to the non-guaranteed surface 3 of the first glass original plate G1, but such a small amount of glass powder GF does not adhere to the guaranteed surface 4.

[0040] As shown in Fig. 4, the upper end face (cut face) Pa of the cut-out first glass original plate G1 has scribe marks Sx formed by the current scribe cutting, and the lower end face (cut face) Pb has scribe marks Sx formed by the previous scribe cutting. These scribe marks Sx are each left as traces of the scribe line S1. Therefore, both scribe marks Sx are formed on the non-guaranteed surface 3 side of the upper end face Pa and the lower end face Pb.

[0041] Referring to FIG. 2, when the second cutting step C is performed, the first glass original sheet G1 is suspended and supported in a vertical position. In this second cutting step C, first, two scribe wheels 7 form scribe lines S2 at predetermined positions (positions slightly inward in the width direction from the edge portions) on both widthwise ends Ga of the first glass original sheet G1. Specifically, the two scribe wheels 7 press predetermined positions on both widthwise ends Ga on the non-guaranteed surface 3 of the first glass original sheet G1 while moving from the position indicated by the dashed line to the position indicated by the solid line, thereby forming two scribe lines S2 along the vertical direction on the non-guaranteed surface 3 of the first glass original sheet G1. In the illustrated example, the two scribe lines S2 do not reach both vertical edges of the glass ribbon GR, but they may reach both edges. In this case, the two scribe lines S2 may be formed simultaneously or separately over time. Next, with the guaranteed surface 4 of the first glass blank G1 supported by two rear support members 8, the first glass blank G1 is bent and split along the two scribe lines S2. Specifically, with the rear support members 8 supporting portions of the first glass blank G1 slightly toward the center in the width direction relative to the two scribe lines S2, both widthwise ends Ga of the non-guaranteed surface 3 of the first glass blank G1 are pressed toward the back side (guaranteed surface 4 side) with a pusher (not shown), thereby bending and splitting the first glass blank G1. By scribing and cutting at these two locations, both widthwise ends Ga of the first glass blank G1, including the edge portions, are removed. This results in a second glass blank G2 without edge portions. In this case, the scribing and cutting at the two locations may be performed simultaneously or separately over time. When the scribing and cutting at these two locations is performed, a large amount of glass powder GF scatters toward the non-guaranteed surface 3 of the second glass blank G2, as shown in FIG. 5. Therefore, a considerable amount of glass powder GF adheres to the non-guaranteed surface 3 of the second glass original plate G2 in addition to the glass powder adhered in the first cutting process B described above, but such a large amount of glass powder GF does not adhere to the guaranteed surface 4.

[0042] 6, scribe marks Sx formed by scribing exist on the end faces (cut faces) Pc and Pd on both sides in the width direction of the second glass original plate G2. These scribe marks Sx are all formed on the non-guaranteed surface 3 side of the end faces Pc and Pd on both sides in the width direction.

[0043] FIG. 7 is a perspective view illustrating an example of the state of implementation of the storage step D. As shown in the figure, in the storage step D, the second glass original sheets G2 cut in the second cutting step C are suspended and supported in a vertical position and loaded on a pallet 10 alternately with the protective sheets 9. Therefore, the second glass original sheets G2 to be loaded on the pallet 10 are oriented along a vertical plane. In contrast, the back support surface 11a of the back support portion 11 of the pallet 10 is an inclined surface that slopes rearward as it moves upward. The inclination angle of the back support surface 11a with respect to the horizontal plane is, for example, 60° to 85°. Therefore, the glass original sheet laminate 12 composed of the second glass original sheet G2 and the protective sheet 9 loaded on the pallet 10 is also oriented vertically, but is inclined in accordance with the back support surface 11a. In this case, the second glass original sheet G2 is suspended and supported while being cut in the second cutting step C and loaded onto the pallet 10, so that the front main surface 3 of the second glass original sheet G2 is the non-guaranteed surface and the rear main surface 4 is the guaranteed surface 4. In this embodiment, the protective sheet 9 is a foamed resin sheet, but it may also be a non-foamable resin sheet or interleaf paper.

[0044] In this situation, as shown in FIG. 8 , when the second glass original sheet G2 and the protective sheet 9 are sequentially stacked on the pallet 10, the corner Px between the guaranteed surface 4 of the second glass original sheet G2 to be loaded and its lower edge Pb may abut against the non-guaranteed surface 3 of the second glass original sheet G2 in the front row of the stacked sheets. In this case, after the abutment, the corner Px slides downward on the non-guaranteed surface 3, causing the second glass original sheet G2 to be loaded to assume the tilted position described above. While this action may cause scratches on the non-guaranteed surface 3 of the second glass original sheet G2 in the front row of the stacked sheets, it does not cause scratches on the guaranteed surface 4. Therefore, the guaranteed surface 4 is reliably protected. Furthermore, because the scribe marks Sx are present on the lower edge Pb of the second glass original sheet G2 to be loaded on the non-guaranteed surface 3 side, even if the abutment or sliding occurs, the corner Py where the scribe marks Sx are formed does not abut or slide. Here, since the scribe marks Sx have many cracks, if abutment or sliding occurs between the scribe marks Sx and the non-guaranteed surface 3 of the second glass original plate G2, glass powder may be generated from the scribe marks Sx or breakage may occur starting from the scribe marks Sx. However, such abutment or sliding does not occur at the corners Py where the scribe marks Sx are formed, so such problems do not occur.

[0045] FIG. 9 is a perspective view illustrating a glass original sheet package Z produced in the storage process D. As shown in the figure, the glass original sheet package Z includes glass original sheet stacks 12 in which second glass original sheets G2 and protective sheets 9 are alternately stacked in a vertical position (strictly speaking, in the inclined position described above), and a pallet 10 on which the glass original sheet stacks 12 are loaded. The glass original sheet package Z also includes packaging tools such as cable ties Ba to prevent the glass original sheet stacks 12 from collapsing. The pallet 10 includes a back support portion 11 having the inclined back support surface 11a described above, and a bottom support portion 13 that supports the bottom of the glass original sheet stacks 12. The bottom support surface 13a of the bottom support portion 13 is an inclined surface that slopes upward as it moves toward the front. The inclination angle of this bottom support surface 13a with respect to the horizontal plane is, for example, 5° to 30°. 4, 6, and 8, all of the second glass original plates G2 in the glass original plate laminate 12 have a front main surface 3 as a non-guaranteed surface and a rear main surface 4 as a guaranteed surface. All of the second glass original plates G2 have scribe marks Sx on the non-guaranteed surface 3 side of all four end faces Pa to Pd along the four sides.

[0046] The storage process D includes a transfer process in which the second glass original sheet G2 and the protective sheet 9 stacked on the pallet 10 are transferred in the form of a glass original sheet package Z. The transfer process involves transporting the glass original sheet package Z to another factory or transporting it within the same factory. During the transfer process, as shown in FIG. 10 , due to shaking, vibration, etc., the lower end face Pb of the second glass original sheet G2 may shift away from the rear support portion 11 of the pallet 10 (a shift that reduces the inclination angle of the second glass original sheet G2 relative to the horizontal plane). If this shift occurs, friction may occur at the corner Px between the guaranteed surface 4 of the second glass original sheet G2 and the lower end face Pb, or the pressure acting on the corner Px may increase. However, because the corner Px does not have a scribe mark Sx, the generation of glass powder and breakage due to the friction and increased pressure can be prevented.

[0047] FIG. 11 is a perspective view illustrating the implementation of the position change process E. As shown in FIG. 11, in the position change process E, first, the glass original sheet package Z produced in the storage process D and subjected to the transport process is unpacked, and one second glass original sheet G2 and one protective sheet 9 are sequentially removed as a set from the pallet 10. The removed set of second glass original sheet G2 and protective sheet 9 is transported toward the position change table 14 in a suspended state. During this transport, the protective sheet 9 is placed in front of the second glass original sheet G2. The front main surface 3 of the second glass original sheet G2 is the non-guaranteed surface, and the rear main surface 4 is the guaranteed surface. The second glass original sheet G2 and protective sheet 9 are transported in a direction perpendicular to both main surfaces 3 and 4 of the second glass original sheet G2. In this case, it is preferable that the protective sheet 9 be superimposed on the front of the second glass original sheet G2 and transported by the same chuck member provided in the hanging device (not shown).

[0048] The position change table 14 has a support plate 15 and a receiving plate 16. When the second glass original plate G2 and the protective sheet 9 are transported to the installation location of the position change table 14, the position change table 14 is in the state shown by the dotted line in the figure. In this state, the mounting surface 15a of the support plate 15 is an inclined surface that slopes forward as it moves upward. The inclination angle of this mounting surface 15a with respect to the horizontal plane is, for example, 60° to 85°. In addition, in this state, the receiving surface 16a of the receiving plate 16 is an inclined surface that slopes upward as it moves rearward. The inclination angle of this receiving surface 16a with respect to the horizontal plane is, for example, 5° to 30°. The transported second glass original plate G2 and protective sheet 9 are placed on the position change table 14, which is in the state shown by the dotted line. At this point, the front surface 9a of the protective sheet 9 contacts the mounting surface 15a of the support plate 15, and the non-protective surface 3 of the second glass original sheet G2 contacts the rear surface 9b of the protective sheet 9. The position change table 14 then rotates in the direction of arrow b, changing from the state indicated by the dotted line to the state indicated by the solid line. This places the second glass original sheet G2 and the protective sheet 9 in a flat position. Specifically, the protective sheet 9 is placed in a flat position on the mounting surface 15a of the support plate 15, and the second glass original sheet G2 is placed on the protective sheet 9. At this time, the upper main surface 4 of the second glass original sheet G2 becomes the protected surface. The second glass original sheet G2 and the protective sheet 9 are fed from the position change table 14 while remaining in this flat position. The position change table 14 then rotates in the direction of arrow c, returning to its original position (the state indicated by the dotted line). In this state, the subsequent second glass original plate G2 and protective sheet 9 that have been removed from the pallet 10 and transported are placed on the position change table 14, and the same operations as those described above are repeatedly performed. Note that the position change table 14 does not necessarily have to have the backing plate 16, but in this case, it is preferable that the backing plate 16 is configured to be able to hold the second glass original plate G2 and protective sheet 9 by suction or the like.

[0049] FIG. 12 is a perspective view illustrating the implementation of the third cutting step F. As shown in the figure, in the third cutting step F, a total of four scribe lines S4 are first formed on the guaranteed surface 4 of the second glass original sheet G2, which has been fed from the above-mentioned position change table 14 and arrived on the support table 17 in a flat position, using a scribe wheel or the like (not shown). Two of the scribe lines S4 along the vertical direction (front-to-back direction) are formed at positions spaced a short distance inward from the two end faces Pa and Pb along the vertical direction, and two scribe lines S4 along the horizontal direction (left-to-right direction), which are perpendicular to the two scribe lines S4, are formed at positions spaced a short distance inward from the two end faces Pc and Pd along the horizontal direction. The second glass original sheet G2 is placed with its non-guaranteed surface 3 in contact with the upper surface 9b of the protective sheet 9, which is placed flat on the support table 17. The second glass original sheet G2 and protective sheet 9 are fed from the support stand 17 in this state and transported by a conveyor (not shown). During this transport process, a folding / splitting member (not shown) pushes up the areas where the scribe lines S4 of the second glass original sheet G2 are formed from below the protective sheet 9, folding / splitting the second glass original sheet G2 along the scribe lines S4. By scribing and cutting by folding / splitting at these four locations, four unnecessary portions Gz are removed from the second glass original sheet G2, and a glass sheet g of the desired size is cut out. Note that in the third cutting process F, multiple glass sheets g of the desired size may be cut out from a single second glass original sheet G2. Furthermore, the removal of the four unnecessary portions Gz by folding / splitting does not need to be performed simultaneously. For example, two scribe lines S4 may be formed to remove two unnecessary portions Gz, and then the remaining scribe line S4 may be formed to remove the remaining unnecessary portion Gz.

[0050] In this third cutting process F, when the second glass original sheet G2 is fed or transported, its non-guaranteed side 3 comes into contact with the upper surface of the support table 17 or the conveyor via the protective sheet 9. Therefore, the non-guaranteed side 3 of the second glass original sheet G2 is easily scratched, but the guaranteed side 4 does not suffer from such defects and is therefore reliably protected. Furthermore, the second glass original sheet G2 has scribe marks Sx formed on the non-guaranteed side 3 (lower side) of each of the end faces Pa to Pd. If the scribe marks Sx come into contact with the upper surface of the support table 17 or the conveyor, this could result in glass powder or breakage. However, because the second glass original sheet G2 is placed on the protective sheet 9 (a foam resin sheet), the cushioning and elasticity of the foam resin sheet 9 make such defects less likely to occur. Furthermore, when the cut glass sheet G is transported, its non-guaranteed side 3 comes into contact with the upper surface of the support table 17 or the conveyor via the protective sheet 9, so its guaranteed side 4 is reliably protected. Furthermore, since the glass sheet g has scribe marks Sx formed on the guaranteed surface 4 side (upper side) of each of the end faces pa to pd, the scribe marks Sx cannot come into contact with the conveyor.

[0051] Furthermore, in this third cutting step F, glass powder due to scribing adheres to the guaranteed surface 4 of the glass plate g. However, since the cleaning treatment described below is performed as soon as possible after the glass plate g is cut out, in other words, the number of treatments performed on the glass plate g from the time the glass plate g is cut out until the cleaning treatment described below is reduced as much as possible, it is possible to prevent the guaranteed surface 4 of the glass plate g from being damaged by the glass powder adhering to the guaranteed surface 4.

[0052] FIG. 13 is a perspective view illustrating the implementation status of the processing step G, cleaning step H, drying step J, and stacking step K. As shown in the figure, in the processing step G, the end faces pa to pd of the glass plate g cut out in the third cutting step F are ground and polished using a grinding wheel 18 and a polishing wheel 19. During this grinding and polishing, the glass plate g is held on a surface plate (not shown) and is carried in and out of the surface plate by a conveyor (not shown). In this processing step G, too, the upper main surface 4 of the glass plate g is the guaranteed surface, and the lower main surface 3 is the non-guaranteed surface. In addition, the protective sheet 9 is removed between the third cutting step F and the processing step G. The grinding and polishing are performed on the four end faces pa to pd of the glass plate g by, for example, changing the orientation of the glass plate g by 90° in a plan view. In this case, in the plan view shown in FIG. 14 , each of the end faces pa to pd of the glass sheet g before grinding and polishing has scribe marks Sx formed on the guaranteed surface 4 side, so the portion of each of the end faces pa to pd on the guaranteed surface 4 side has good linearity. In contrast, each of the end faces pa to pd does not have scribe marks Sx formed on the non-guaranteed surface 3 side, so the linearity of each of the end faces pa to pd on the non-guaranteed surface 3 side is poorer than that on the guaranteed surface 4 side. Therefore, when each of the end faces pa to pd of the glass sheet g is cut and polished, chips and cracks are less likely to occur on the guaranteed surface 4 side of the glass sheet g, leading to improved quality of the glass sheet g. Moreover, by performing this processing step G, the scribe marks Sx on the glass sheet g are eliminated, preventing the generation of glass powder and breakage in subsequent processes.

[0053] As shown in FIG. 13 , the glass sheet g that has completed the processing step G is transported by a conveyor while maintaining its flat position, and is then cleaned by a cleaning device 20 in a cleaning step H. This cleaning removes glass powder that has adhered to the guaranteed surface 4 of the glass sheet g during the third cutting step F. Furthermore, the glass sheet g that has undergone the cleaning process is transported by a conveyor while maintaining its flat position, and is then dried by a drying device 21 in a drying step J. In this manner, the glass sheet g is obtained as a finished product. After this, in a stacking step K, the finished glass sheets g and the protective sheets 9 are alternately stacked on a pallet 22 in their flat position. In the cleaning step H and the drying step J, the position of the glass sheet g may be changed from the flat position to a position in which the guaranteed surface 4 is tilted, for example, by 1 to 10 degrees relative to the horizontal plane, in order to facilitate the removal of the cleaning solution.

[0054] In the above embodiment, scribe lines S1, S2 were formed on the non-guaranteed surfaces 3 of the glass original sheets G1, G2 in both the first cutting step B and the second cutting step C, but scribe lines may be formed on the guaranteed surfaces 4 of the glass original sheets in either the first cutting step B or the second cutting step C. From the viewpoint of reliably suppressing adhesion of glass powder to the guaranteed surfaces of the glass original sheets, it is preferable to form scribe lines S1, S2 on the non-guaranteed surfaces 3 of the glass original sheets G1, G2 in both the first cutting step B and the second cutting step C, as in the above embodiment.

[0055] In the above embodiment, the glass ribbon is formed by the overflow downdraw method, but other downdraw methods such as the slot downdraw method or the redraw method may also be adopted. [Explanation of symbols]

[0056] A Molding process B First cutting process C Second cutting process D Storage process E. Posture change process F Third cutting process G Machining process H Cleaning process 3 Non-guaranteed aspects 4 Warranty 9 Protective Sheet 10 palettes 11 Back support part 12 Glass substrate laminate 13 Bottom support part GR Glass Ribbon G1 Glass Plate (First Glass Plate) G2 glass substrate (second glass substrate) Both ends of Ga glass substrate in the width direction g Glass plate Each end face of the Pa~Pd glass substrate pa~pd Each edge of the glass plate Sx Scribe marks Z Glass raw sheet packaging

Claims

1. A method for manufacturing a glass plate, comprising: a forming step of forming a glass ribbon by a down-draw method; a first cutting step of cutting out a glass raw plate from the glass ribbon formed in the forming step by scribing along a width direction; and a second cutting step of holding the glass raw plate that has been subjected to the first cutting step in a vertical position and removing both end portions in the width direction of the glass raw plate by scribing along the vertical direction, wherein a glass plate is obtained from the glass raw plate that has been subjected to the second cutting step, In at least one of the first cutting step and the second cutting step, a scribe line is formed on a non-guaranteed surface of the guaranteed surface which is one main surface of the glass original plate and a non-guaranteed surface which is the other main surface thereof, using a scribe wheel; The method for manufacturing a glass plate further comprises a storage step of stacking the glass original plate and the protective sheet that have undergone the second cutting step in a vertical position on a pallet and storing them, wherein in the storage step, the guaranteed surface of the glass original plate is supported by a back support portion provided on the pallet.

2. The method for manufacturing a glass plate according to claim 1 , wherein a scribe line is formed on the non-guaranteed surface of the glass original plate in both the first cutting step and the second cutting step.

3. The method for manufacturing a glass plate according to claim 1 or 2, wherein the storing step includes a transporting step of transporting the glass blanks and the protective sheets stacked on the pallet.

4. 4. The method for manufacturing a glass plate according to claim 1, wherein the protective sheet is a foamed resin sheet.

5. 5. The method for manufacturing a glass plate according to claim 1, further comprising: a third cutting step of cutting out a glass plate from the glass original plate that has been through the storing step by scribing; and a cleaning step of cleaning the glass plate that has been through the third cutting step, wherein in the third cutting step, a scribe line is formed on the guaranteed surface of the glass original plate while the glass original plate is laid flat and the non-guaranteed surface of the glass original plate is supported from below, and in the cleaning step, the glass plate is cleaned while the glass original plate is laid flat and the non-guaranteed surface of the glass plate is supported from below.

6. The method for manufacturing a glass plate according to claim 5 , further comprising a processing step of processing an edge surface of the glass plate with a processing tool between the third cutting step and the cleaning step.

7. A glass original sheet package including a glass original sheet laminate in which glass original sheets and protective sheets are laminated in a vertical position, and a pallet on which the glass original sheet laminate is loaded, both end faces along the longitudinal direction and end faces along the lateral direction of the glass original plate are cut surfaces by scribe cutting, and at least one of the end faces has a scribe mark on a non-guaranteed surface side of a guaranteed surface which is one main surface of the glass original plate and a non-guaranteed surface which is the other main surface, The pallet is provided with a rear support portion that supports the rear surface of the glass original plate laminate and a bottom support portion that supports the bottom surface of the glass original plate laminate, and the protective surface of the glass original plate is located on the rear support portion side.

8. The glass blank package according to claim 7, wherein both of the longitudinal end faces and the lateral end faces of the glass blank have scribe marks on the non-guaranteed surface side.

Images