TW201247566A - Production method for glass sheet and glass sheet production device - Google Patents

Abstract

When producing a glass sheet, a glass raw material is melted to create molten glass, the molten glass is molded using the downdraw method, a glass ribbon is formed, and the glass ribbon is drawn downwards and annealed while being sandwiched between a plurality of roller pairs disposed along the conveyance direction for the glass ribbon. During molding, both ends of the glass ribbon are cooled while the glass ribbon continues to be sandwiched between the roller pairs and drawn downwards. Each roller in a first roller pair, which is one of the roller pairs used either in molding or annealing, is rotatably driven on the basis of a roller rotation speed determined so as to compensate for roller diameter change.

Description

201247566 VI. Description of the Invention: [Technical Field of the Invention] The present invention relates to a method for producing a glass sheet and a shock for manufacturing a broken board. [Prior Art] The manufacturing method of the glass plate by the down-draw method is that the glass ribbon is stretched to a desired thickness by being pulled downward by the conveyance report, and further, to avoid strain inside, and Avoid the way the glass ribbon is warped and cool. The glass ribbon is cut to a specific size, and is loaded with each other via paper loss or the like, or conveyed in the subsequent step (for example, chemical processing of shape processing and ion exchange). As a method of manufacturing a glass sheet using the down-draw method, it is known that the rotation of each of the transport rollers is controlled by the same load to prevent slippage due to the difference in outer diameter between the transfer rollers. On the other hand, the transfer roller is prevented from being idling (Patent Document 1). According to this, it is possible to prevent breakage of the glass surface and the conveyance roller. Further, in the quenching furnace in which the ambient temperature and the temperature of the glass ribbon are changed in the direction in which the glass ribbon is conveyed, it is preferable to provide the circumferential speed of the conveying roller at each position in the conveying direction of the glass ribbon and the conveying speed of the glass ribbon. The relative speed is 0, but since the thermal expansion coefficient of the glass is different from the thermal expansion coefficient of the conveying roller, and the temperature dependence thereof is also different, the relative speed is not the same between the plurality of conveying roller pairs, and in the relative speed. Produce a difference. Such a difference in relative speed is caused, for example, by a change in the conveying speed or thickness of the glass ribbon, a change in the airflow generated in the quenching furnace, etc., resulting in a change in the temperature of the ring θ 4 clothing/m degree or the glass ribbon in the chilling furnace of the 163507.doc 201247566 And produced. Therefore, as described in Patent Document 1, it is impossible to eliminate the actual conveyance speed of the glass ribbon generated between the plurality of conveyance roller pairs, that is, the actual conveyance speed and conveyance even if the conveyance roller load of the conveyance roller pair is controlled to be equivalent. The S of the relative speed of the circumferential speed is observed, so that the damage of the glass surface caused by the slip cannot be prevented. Further, when between the plurality of conveying roller pairs, the relative speed is not fixed between the required conveying speed of the target speed of the conveyance of the glass ribbon and the peripheral speed of the conveying roller, that is, the difference in relative speed occurs. Under the condition that the actual conveying speed is slower than the necessary conveying speed, the glass ribbon will be deformed above the moving light and cause deformation. On the contrary, under the condition that the real conveying speed is faster than the necessary conveying speed, the glass ribbon is pulled downward. Stretch

S is born from the damage of the surface of the fine damage and broken. Further, since the glass ribbon is continuously formed and cold-cooled for a long period of time, the manufacturing apparatus of the glass sheet undergoes a change with time β, so that the glass sheet can be manufactured to a quality (internal strain, small curvature). The manufacturing conditions at the time of initial setting and cold cooling are also not allowed to maintain a high-quality glass plate due to continuous operation for a long time. In particular, the conveyance of the contact with the glass ribbon causes a change in diameter, which has a large influence on the quality of the glass sheet. [Prior Art Document] [Patent Document 1] [Patent Document 1] Japanese Patent Application Publication No. 2008-501605 [Draft] [Problems to be Solved by the Invention] 163507.doc 201247566 Therefore, in order to solve the above problems, the present invention A first object of the invention is to provide a method for producing a glass sheet which can maintain the manufacture of a high quality glass sheet even if the manufacturing equipment is changed over time due to continuous production of the glass sheet. A second object of the present invention is to provide a circumferential speed distribution in which the circumferential speed of a conveying roller which is changed by the change in the diameter of the conveying roller is maintained, and the peripheral speed of the conveying roller and the conveying speed of the glass ribbon are prevented between the plurality of conveying roller pairs. A difference in the relative speed is produced, whereby a method for producing a glass sheet of a glass sheet excellent in surface quality and a glass sheet manufacturing apparatus can be produced. [Technical means for solving the problem] One aspect of the present invention is a method for producing a glass plate. The manufacturing method includes: a melting step of melting a glass raw material to form a molten glass; a forming step of “forming a molten glass to form a glass ribbon by a pulling method; and a cold cooling step of separating the glass ribbon The plurality of rolls provided in the conveying direction of the glass ribbon are sandwiched and guided downward by oxygen to be quenched. The forming step includes the step of cooling the both ends of the glass ribbon by holding the glass (four)-face held by the roll and depleting it downward. At least one of the above-mentioned pairs of the above-mentioned forming steps and the above-mentioned cold-pressing step, that is, the first pair of rollers, which are determined by the method of compensating for the change of the straightness of the roller It is driven by rotation according to the % turning speed. Another aspect of the invention is a method of making a glass sheet. The manufacturing method comprises: 163507.doc 201247566 a dazzling step, a forming step, a belt; and melting the glass raw material to produce a molten glass; and forming a molten glass using a down-draw method to form a glass 2 cold step, which comprises the glass ribbon The cold is carried out by a plurality of reconciliations along the conveyor side of the glass ribbon. In the above-described cold cooling step, at least any one of the pair of rolls, i.e., the first pair of rolls, is rotationally driven based on the rotational speed of the roll determined by compensating for the diameter change of the roll. In this case, preferably, the step of cooling includes: a detecting step of detecting a direct control change of each of the first pair of rollers by a detecting portion provided along a conveying direction of the glass ribbon; and The control step 'determines the rotation speed of each of the rolls of the i-th roll pair, determines the rotation speed of each of the rolls, and rotationally drives the respective rolls of the i-th roll pair. Preferably, each of the roll sets of the pair of rolls is disposed in a temperature range in which at least the glass transition point is equal to or higher than a glass transition point and a softening point or less in the cold rolling step, and in the above-described cold cooling step, The rotation speed of each of the first roller pairs is determined so as to compensate for the change in the diameter of each of the first roller pairs, and the rollers of the first roller pair are rotationally driven. Preferably, the forming step and the quenching step are performed by controlling the temperature of the glass ribbon as follows. The temperature in the central portion of the glass ribbon is in the region above the softening point of the glass. The end portion in the width direction of the glass ribbon is lower than the end portion. 163507.doc

The temperature in the central region of S -6 · 201247566 is controlled so that the temperature in the central region is substantially uniform. Further, in a region where the temperature of the central portion of the glass ribbon is not higher than the softening point and is higher than the strain point, the tensile stress in the transport direction is applied to the central portion of the glass ribbon to control the glass. The temperature in the width direction of the belt is lowered from the central portion of the glass ribbon toward the end portion. Further, in the forming step and the cooling step, the glass ribbon is controlled such that the temperature gradient between the end portion and the central portion in the width direction of the glass ribbon disappears in a temperature region near the glass strain point of the glass ribbon Temperature distribution. Preferably, in the step of cooling, the glass ribbon is controlled such that the tensile stress in the transport direction acts on the central portion of the glass ribbon in a region where the temperature in the central portion of the glass ribbon is not near the strain point. The temperature distribution is such that the temperature distribution of the glass ribbon becomes lower from the end portion in the width direction of the upper I glass ribbon toward the central portion. Preferably, the cold cooling step includes: a first cold portion step of cooling at a first average cooling rate until a temperature at a central portion of the glass ribbon reaches a cold point; and a second cold rolling step Cooling is performed at the second average cooling rate until the center β degree is reached from the above-mentioned cold point to the strain point _5 generations; and the seventh step is 'cooling at the third average cooling rate until the upper v center# 'The degree of the dish reaches the above strain point-touch from the above strain point. . until. The first average cooling rate is 5.0 ° C /sec or more, the first 163507.doc 201247566 average cooling rate is faster than the third average cooling rate, and the third average cooling rate is faster than the second average cooling rate. Preferably, the method of determining the deviation of the circumferential speed caused by the change in the diameter of each of the rolls of the first roll caused by the thermal expansion of each of the first roll pairs is determined by the first roll pair. The rotation speed is used to rotationally drive the respective rollers of the i-th roller pair. Further, it is preferable that the first roller pair is determined such that the circumferential speed difference caused by the change in the diameter of each of the first roller pairs caused by the abrasion of each of the first roller pairs is compensated. The rotation speed of each of the rolls is driven by the rotation of each of the first pair of parents. A pair of rollers having a roller that is rotationally driven based on a rotational speed of the roller determined by compensating for a change in the diameter of the roller among the plurality of roller pairs includes a second roller pair in addition to the first roller pair. In this case, the manufacturing method includes a detecting step of detecting a diameter of each of the first roller pair and the second roller pair by a plurality of detecting portions provided along a conveying direction of the glass ribbon Variety. Further, between the respective rolls of the first pair of rolls and the rolls of the second pair of rolls, the diameter of each of the rolls is determined to be fixed so that the relative speed of the peripheral speed of the rolls and the conveying speed of the glass ribbon are fixed. The rotational speed of each of the above rolls is varied. Preferably, the manufacturing method detects the temperature of the glass ribbon by detecting a state of the glass ribbon in a direction in which the glass ribbon is conveyed in the direction in which the glass ribbon is conveyed, and uses the detected thermal expansion of the glass in the temperature of the glass ribbon. Coefficient, 163507.doc 201247566 Detects the culture of the above-mentioned glass ribbon conveyance speed caused by the thermal expansion of the above-mentioned glass ribbon, and determines the above-mentioned nip roller pair by compensating for the deviation between the transport speed of the glass ribbon and the peripheral speed of the roller. The rotational speed of each roller. The thickness of the glass plate obtained by subjecting the glass ribbon to a cold is, for example, 0.5 mm or less. Further, an aspect of the present invention is a glass sheet manufacturing apparatus. The apparatus includes: a molding apparatus which uses a down-draw method to form a glass ribbon from molten glass; and a quenching apparatus which presses the glass ribbon by a plurality of conveying roller pairs and pulls it downward to perform cold cooling. The subcooling device includes the plurality of conveying roller pairs, the detection control unit, and the driving unit. The plurality of conveying roller pairs are disposed along the conveying direction of the glass ribbon, and the glass ribbon is conveyed by pulling the glass ribbon downward. The detection control unit includes a plurality of conveyance roller state detecting sections that are provided along the conveyance direction of the glass ribbon and that detect a change in the diameter of the conveyance roller of the conveyance roller pair. The driving unit is configured to maintain a circumferential speed distribution between the plurality of transporting pairs when the relative speed of the peripheral speed of the transport roller and the transport speed of the glass ribbon is fixed between the plurality of transport roller pairs The rotation speed of each of the conveyance rollers determined by the change in the diameter of the conveyance roller is detected, and the conveyance roller is rotationally driven. Preferably, the conveyance roller state detecting unit detects a change in diameter of the conveyance report based on a temperature of the conveyance roller of 163507.doc -9·201247566 degrees, and the drive unit compensates the roller caused by thermal expansion of the conveyance roller. The deviation of the peripheral speed of the transport roller caused by the change in diameter and the circumferential speed distribution is determined based on the rotation of each of the transport rollers determined by the detected thermal expansion coefficient in the /ja degree of the transport roller The speed is such that the conveying roller is rotationally driven. Preferably, the detecting unit further includes a plurality of glass state detecting portions that are provided along the conveying direction of the glass ribbon to detect the state of the glass ribbon, and the driving portion is configured based on the circumferential speed distribution set by the state of the glass ribbon. The rotation of the transport roller is driven. Preferably, the glass state detecting unit detects the temperature of the glass ribbon, and the driving unit transmits the glass ribbon based on a glass thermal expansion coefficient in the temperature of the glass ribbon detected and corresponding to thermal expansion of the glass ribbon. The circumferential speed distribution set by the speed change causes the conveyance roller to be rotationally driven. Preferably, the conveyance roller state detecting unit detects a change in the diameter of the conveyance roller based on the amount of wear of the conveyance roller, and the drive unit compensates for a change in the diameter of the conveyance roller caused by the detected abrasion of the conveyance roller. The conveyance roller is rotationally driven by the rotation speed of each of the conveyance reports determined by the deviation of the peripheral speed of the conveyance roller from the circumferential speed distribution. The thickness of the glass plate obtained by quenching the above glass ribbon is, for example, 0.5 mm or less. 163507.doc 201247566 [Effects of the Invention] The method for producing a glass sheet is to maintain a high-quality glass sheet even if the glass-belt-contacting production equipment is changed over time due to continuous production of the glass sheet for a long period of time. . Further, in the method for producing a glass sheet and the glass sheet manufacturing apparatus, the peripheral speed of the conveyance crucible which is changed by the change in the diameter of the conveyance roller can be maintained at the set circumferential speed distribution, and the circumference of the conveyance roller can be avoided between the plurality of conveyance roller pairs. The difference between the speed and the relative speed of the transport speed of the glass ribbon. Thereby, a glass plate excellent in surface quality can be produced. [Embodiment] Hereinafter, a method for producing a glass sheet and a glass sheet manufacturing apparatus of the present invention will be described in detail. The method and apparatus for producing a glass sheet according to the embodiment or its modification are at least one of a forming step of a method for producing a glass sheet and a pair of rolls (a pair of cooling rolls and a pair of conveying rolls) used in the step of cooling. Each of the rollers of the pair of rollers (the first pair of rollers) is driven to rotate by β x based on the rotational speed of the roller determined by the diameter of the compensation roller, and the cold cooling step is at least one of a plurality of conveying reports. Each of the rolls of the (second roll pair) is rotationally driven based on the rotational speed of the roll which is determined in such a manner as to compensate for the change in the diameter of the roll. The rotation speed of such a roller is determined by compensating for the change in diameter by detecting the change in the diameter of each of the ith reports. Namely, the rotation speed of the control roller is fed back based on the detection result of the change in the diameter of the roller. Alternatively, the rotational speed of the rolls is determined based on the information on the number of days of use of each of the first pair of rolls. That is, based on the information of the use of each roller, the rotation speed of the roller is determined by the financial position 163507.doc •11-201247566 degrees. The “Information on the number of days of use” is used to change the diameter of the roller based on the wear of the first roller pair. The conversion speed is determined based on the converted value of the change in the diameter of the roll. The first roller pair which determines the rotation speed of such a roller may be singular or plural. The "diameter change of the compensation roller" means a reasonable circumferential speed of the roller before the change in diameter is maintained in consideration of the change in the diameter of each roller of the first roller pair. In addition, the following statements in this specification are as follows. The term "cold cold point" refers to a range in which the viscosity η of the glass is logll=12.5 to 13.5. The so-called cold spot of glass refers to the temperature at which the viscosity η of the glass reaches 1〇gr) = 1 3 . The strain point of the glass refers to a temperature at which the viscosity η of the glass reaches 1〇gT1==14 5 . The vicinity of the strain point of the glass refers to a range in which the viscosity η of the glass reaches a temperature of logn = 14 to 15. The central region of the glass ribbon refers to a range within 85% of the width of the width direction of the glass ribbon in the width direction of the glass ribbon. The central portion of the glass ribbon refers to the center of the width direction of the glass ribbon. The fact that the temperature in the central portion of the glass ribbon is substantially uniform means that the temperature is within the allowable range of ±20 °C. The end portion of the glass ribbon refers to a range within 200 mm from the edge in the width direction of the glass ribbon. (Manufacturing Method of Glass Plate) FIG. 1 is a flow chart showing the method of manufacturing the glass plate of the present embodiment. 163507.doc

• 12· S 201247566 The manufacturing method of the glass plate mainly includes a melting step (step si〇), a clarification step (step S20), a stirring step (step s3〇), a forming step (step S40), and a cold cooling step (step S5〇). ), a paneling step (step (4)), and a shape processing step (step S70). In the melting step (step sl), in the melting furnace (not shown), the glass raw material is heated to a high temperature by direct heating from above, and direct heating by flowing a current into the glass to produce a molten glass. . The dissolution of the glass can also be carried out by other methods. Next, a clarification step (step S2 〇) is performed. The clarification step is carried out in a state where the molten glass is accumulated in a liquid tank (not shown), for example, the temperature of the molten glass is increased as compared with the heating in the melting step, whereby the defoaming of the bubbles in the molten glass is promoted. Thereby, the bubble content in the finally obtained glass plate can be lowered, and the yield can be improved. The clarification step can also be carried out by other methods, for example, by using a clarifying agent to remove the bubbles in the molten glass while the molten glass is accumulated in the liquid tank. The clarifying agent is not particularly limited. For example, a metal oxide such as tin oxide or iron oxide is used. Specifically, the clarification step in this case is carried out by a redox reaction of a metal oxide whose valence is varied in the molten glass. In the molten glass at a high temperature, the metal oxide releases oxygen by the reduction reaction, and the oxygen becomes a gas, and the bubbles in the molten glass grow to float on the liquid surface. Thereby, the bubbles in the molten glass are defoamed. Alternatively, the bubble of oxygen is sucked up by the gas in the other bubbles in the molten glass to grow, thereby floating on the liquid surface of the molten glass. Thereby, the bubbles in the glazed glass are defoamed. Further, if the temperature of the molten glass is lowered, the metal oxide absorbs oxygen remaining in the molten glass by the oxidation reaction 163507.doc -13 - 201247566 to reduce the bubbles in the molten glass. Next, the stirring step is performed (step S30). The agitation step mechanically agitates the molten glass by means of a search device to maintain the chemical and thermal uniformity of the glass. Thereby, the unevenness of the glass such as the pulse can be suppressed. Next, a forming step (step S40) is performed. The forming step is a pull-down method. The following methods include an overflow down-draw method or a flow-down method, such as Patent No. 3586142, or a known method using the apparatus shown in Figs. 3 and 4. The forming steps in the downdraw method will be described below. Thereby, a glass ribbon having a plate thickness of a specific thickness and width is formed. As the forming method, in the down-draw method, the overflow down method is preferable, but the orifice down method can also be used. The forming step includes a step of cooling the both ends of the glass ribbon while the glass ribbon formed by molding is pulled by the crucible pair and pulled downward in the conveying direction (the direction of the downstream side). Next, the step of cooling is performed (step S50). The Xu cold step is to form a glass ribbon which is formed into a plate shape to control the cooling rate without strain or strain reduction, and is cooled to below the freezing point in the quench furnace shown in Figs. 3 and 4 . Specifically, 'the vicinity of the width direction of the end portion in the width direction of the glass ribbon' is held by at least two or more transport roller pairs provided along the direction in which the glass ribbon is conveyed, and is set in advance. The conveying speed is pulled downwards and the side is cold. Fig. 2 is a view showing an example of the flow of the step of cooling. The cold step includes a detecting step (step S51), a speed determining step (step S52)', and a speed controlling step (step S53). Further, although the method of manufacturing the glass sheet of the present embodiment includes the detecting step (step S51), it may be as described in the following modification.

163507.doc • 14- S 201247566 The detection step is not performed, and the speed determination step (step S52) and the speed control step (step S53) are included in the cold step. In the detecting step (step S51), the diameters of the respective conveying rollers of the plurality of conveying roller pairs are detected by a plurality of detecting portions provided corresponding to the plurality of conveying roller pairs in the conveying direction of the glass ribbon. The change in the diameter of the conveying roller is, for example, the amount of change in the diameter of the conveying roller calculated based on the temperature of the conveying roller or the amount of wear of the conveying roller. The detecting portion in this case includes, for example, a temperature sensor or a distance measuring sensor described below, and a computer connected to the sensors. The diameter 'is a diameter or a radius of a conveyance roller. The speed determination step (step S52) sets a plurality of conveying roller pairs when the relative speed of the peripheral speed of the plurality of conveying inter-feeding conveying rollers and the conveying speed of the glass ribbon is fixed, that is, when no difference occurs in the relative speed. The circumferential speed distribution 'and the rotation speed of each conveying roller is determined so as to maintain the set circumferential speed distribution based on the detected change in the diameter of the conveying roller. As the circumferential speed distribution ', for example, a peripheral speed ratio between a plurality of conveying roller pairs and a specific peripheral speed of each conveying view can be used. Here, since the relative speed of the glass ribbon is not damaged or the shape is deformed, the difference in the relative speed means that the relative speed of a pair of the plurality of conveying roller pairs is 〇, and the other relative speeds The relative velocity such as the enthalpy has a distribution β. For example, when the diameter change of the conveying roller is based on the temperature-calculated amount of the thermal expansion of the conveying roller (the amount of change in the diameter), specifically, the following detecting portion 37 is used. In the same manner as the speed determining unit 38, the circumferential speed of the conveying roller caused by the change in the diameter of the roller due to the thermal expansion of the conveying roller is compensated by the detected coefficient of thermal expansion of the roller in the temperature of the conveying roller. 15 201247566 The deviation of the distribution is such that the rotation speed of the conveyance roller is determined such that the circumferential speed of each conveyance roller is maintained at the set circumferential speed distribution. The thermal expansion coefficient of the transfer roller is previously stored in the speed determining unit 38. Further, the peripheral speed of the conveying roller is determined, for example, by adjusting the thickness of the glass plate to be produced by the formed glass ribbon. Further, for example, when the change in the diameter of the transfer roller is based on the amount of change in the radius of the conveyance report calculated based on the wear amount, specifically, the conveyance roller is compensated for as described in the second embodiment described below. The deviation of the circumferential speed of the conveyance report caused by the change in the radius of the conveyance report due to the wear and tear, that is, the circumferential speed of each conveyance roller is maintained at the set circumferential speed distribution, and the rotation of the conveyance roller is determined. speed. Further, the speed determining unit 38 may determine the rotational speed of each of the transport rollers based on the contents input by the operator. In this case, the operator can calculate the rotational speed of each transport roller based on the detected diameter change of the transport report to maintain the set circumferential speed distribution. For example, when the diameter change of the conveyance report is the above-described thermal expansion amount, the operator can compensate the circumferential speed of the conveyance roller caused by the change in the diameter of the roller due to the thermal expansion of the conveyance roller based on the detected temperature of the conveyance roller. The method of calculating the deviation of the circumferential speed distribution 'calculates the circumferential speed of each of the conveying rollers to the set circumferential speed distribution' is calculated as the rotational speed of the conveying roller. The rotation speed of each of the transports that have been input after the calculation is determined by the speed determining unit 38, and the rotation of the transport roller is controlled in the speed control step (step S53). The speed control step (step S53) is based on determining in the speed decision step

163507.doc Μ S 201247566 The rotation speed controls the rotation of the conveying roller. Specifically, after the cutting is performed, the cutting step (step (10)) is performed. 5 ' Cut the continuously formed glass ribbon into a fixed length per glass to the glass plate. <& , the shape processing step (step (4)). The shape processing not only cuts the size or shape of the specific glass plate, but also performs the physical properties of the glass end face; ^ ° shape processing can be used to manufacture a cutting machine Or the physical method of laser, you can also use (4) and other chemical methods. Also 'preferably' the forming step and the cold (4) is in the zone where the temperature is above the softening point of the glass, The end of the width 2 is lower than the temperature of the central region sandwiched by the end portion, and the temperature of the central region is substantially uniform - to control the temperature of the glass (4) to suppress the shrinkage of the width direction of the glass ribbon. In the aspect of suppressing the warpage of the glass sheet, it is preferable that the tensile stress in the conveying direction acts on the glass ribbon in the region where the temperature of the central portion of the glass ribbon does not reach the softening point and is higher than the strain point. Central way, control The temperature of the glass ribbon is such that the temperature in the width direction of the glass ribbon descends from the central portion of the glass ribbon toward the end portion. Further, in terms of suppressing the internal strain of the glass ribbon, it is preferable that the temperature of the glass ribbon reaches the strain point. In the temperature region in the vicinity, the temperature distribution of the glass is controlled such that the temperature gradient between the end portion and the central portion in the width direction of the glass ribbon disappears. Further, it is preferable to suppress the warpage of the glass ribbon in the conveying direction. In the region where the temperature in the central portion of the glass ribbon is not near the strain point, and the tensile stress in the transport direction acts on the central portion of the glass ribbon to control the temperature distribution of the glass ribbon of 163507.doc •17·201247566, The temperature distribution of the glass ribbon is decreased from the end portion in the width direction of the glass ribbon toward the central portion. Further, preferably, the cold cooling step includes a second cooling step of cooling at an average cooling rate until the center of the glass ribbon The temperature of the part reaches the cold point; the second cooling step 'cools it at the second average cooling rate' until the temperature in the central part of the glass ribbon is from the cold The strain point is reached until the thief; and the third cooling step is performed at the third average cooling rate until the temperature in the central portion of the glass ribbon is from the strain point of 5 (rc reaches the strain point. In this case) i The average cooling rate is 5 〇 or more, and the 1st average cooling rate is faster than the 3rd average cooling rate, and the 3rd average cooling rate is faster than the 2nd average cooling catch. Xiao Wei, the average cooling rate is high to low. The order is the first average cooling rate and the third average cooling rate 'the second average cooling rate. The cooling rate in the direction in which the glass ribbon is conveyed affects the heat shrinkage of the produced glass sheet. However, as described above, in the cold step The glass sheet having a better heat shrinkage rate can be obtained by increasing the glass sheet by increasing the cooling rate. Further, the method for manufacturing the glass sheet includes a washing step and an inspection step, but the steps are omitted. Description. Further, the clarification step and the stirring step can be omitted, respectively. (Glass plate manufacturing apparatus) Fig. 3 and Fig. 4 are schematic configuration diagrams of a glass sheet manufacturing apparatus 1 according to a third embodiment of the present invention. The glass sheet manufacturing apparatus 1 of the present embodiment and the method of manufacturing the glass sheet using the glass sheet manufacturing apparatus 1 can be preferably applied to a liquid b day display device or an organic EL (Electro Luminescence) 163507.doc 201247566 display. The manufacture of a cover glass for a glass substrate of a flat panel display or a display surface of a portable terminal device. The reason for this is that liquid crystal display devices or organic EL display devices have required high precision and high quality in recent years, and therefore high surface quality is required for the glass substrates used therefor. Further, the reason is that since the cover glass is applied to the display surface of the device, etc., the surface quality of the glass substrate for the glass substrate is required. In the glass plate manufacturing apparatus 1 , the glass plate glass plate manufacturing apparatus 1 is manufactured by the molten glass A by the down-draw method, and the furnace chamber 11 which isolate|separates the heat insulation board 21 and 22 '23 arrange|positioned by the three positions of the up-down direction. 1 Xu cold furnace 12, second Xu cold furnace 13, and a panel chamber (not shown). The heat insulating panels 21 to 23 are plate-shaped members including heat insulating materials such as ceramic fibers. The transfer holes 16 are formed in the heat insulating plates 21 to 23, respectively, so that the glass ribbons b described below are directed downward through the heat insulating plates 21 to 23, respectively, in Fig. 3, and are in contact with the furnace wall 15 described below for easy understanding. The two portions in the horizontal direction are removed, and the illustration is omitted. However, in the glass ribbon B, two portions in the horizontal direction are integrally connected to the front side and the back side of the paper. In addition, in FIGS. 3 and 4, there is an example in which the insulation is used to separate the three clamps. However, the number of the heat shields and the installation position are not particularly limited. More than that. Furthermore, since the number of the heat shields is more than one, the more space that can independently control the ambient temperature, the easier the adjustment of the ambient temperature (the adjustment of the cold condition) becomes, and therefore, preferably, the cold storage device 3 & A number of insulation panels are placed to isolate multiple spaces. In other words, the Xu cold furnace may be provided with four or more, but it is more preferable to provide three or more f glass plate manufacturing apparatuses including a forming device 2, a cold cooling device 3, and a cutting device 4. 163507.doc .19· 201247566 The forming apparatus 2 is a device for forming the glass ribbon B from the molten glass A by a down-draw method. The forming apparatus 2 includes a furnace chamber u surrounded by a furnace wall 15 assembled of refractory bricks or block-shaped electroformed refractories. A forming body 10 and a pair of rolls (cooling roll pairs) 17 are provided in the furnace chamber. The molded body 1 includes a groove 10a (see Fig. 4) opened upward, and the molten glass A flows in the groove 1A. The formed body 10 includes, for example, a brick. The roller pair 17 is provided in a pair at a position corresponding to the end portions on both sides in the width direction of the molten glass A fused to the lower end of the molded body 1 ,, and the molten glass A is pulled downward while being pulled downward. A pair of cooling rolls cooled at both ends of the glass ribbon B. Further, the left-right direction in the paper surface in Fig. 3 and the direction perpendicular to the paper surface in Fig. 4 are the width directions of the glass ribbon B. In Fig. 3 and Fig. 4, the direction of conveyance of the glass ribbon 8 is in the upper and lower directions in the plane of the paper. In addition, in FIGS. 3 and 4, the molded body 1 is not provided in isolation from the roller pair 17 but it is easy to adjust the cold conditions, and a heat insulating plate may be provided for isolation therebetween. . Also, the report 17 can be set to two or more pairs. In this case, in the forming step, when the temperature of the glass ribbon 3 is in a temperature range from a temperature higher than the softening point to a vicinity of the near-cold point, it is preferable to apply tension to both end portions of the glass ribbon. Cooling is performed in such a manner that the viscosity 11 at both end portions reaches 1 = 11 = 9.0 to 14.5. This cooling is performed by, for example, holding the both end portions of the glass ribbon b by the pair of rollers 17 to perform β by cooling the both ends of the glass ribbon 17 by the respective rollers of the roller pair 17 as the cooling roller. The viscosity rises, so that the shrinkage of the width of the glass ribbon can be suppressed. (Xu cold device) The X-cooling device 3 system transports the β-face of the glass belt from a plurality of pairs to the Μ, β clip 163507.doc • 20- 201247566 The holder is dragged downwards while performing a cold. The X-cooling device 3 includes a second cooling furnace 12 and a second quenching furnace 13 which are disposed adjacent to the furnace chamber. The first Xu cold furnace 12 and the second quench furnace 13 are surrounded by the furnace wall 15 which also constitutes a furnace chamber. The chilling device 3 is provided with a heating mechanism that is automatically controlled by the following computer, which is disposed along the conveying direction of the glass ribbon B, in the second cooling furnace 12 and the second chill furnace 13. The heating mechanism is not particularly limited, and for example, an electric heater can be used. In the first Xu-cooling furnace 12, three transporting pairs 18 arranged along the transport direction of the glass ribbon B are provided. In the second cooling furnace 3, four conveying roller pairs 19 disposed along the conveying direction of the glass ribbon B are provided. Further, the rapid cooling device 3 includes the detection control unit 30 and the driving unit 32 (see Fig. 5). Further, the number of the transport roller pairs 18 and 19 in the cold furnaces 12 and 13 is not limited, and it is sufficient to provide at least "solid." The transport roller pairs 18 and 19 are carried by pulling the glass ribbon b downward to convey the glass ribbon. B. Each of the transport roller pairs 18 includes four transport rollers 18a disposed on both sides of the glass ribbon B so as to sandwich a region adjacent to both end portions in the width direction of the glass ribbon b, and will be located at the glass ribbon b The two transport rollers 18a on the same side are connected to the two drive shafts 18b disposed on both sides of the glass ribbon B. Each of the transport roller pairs 19 includes a region adjacent to both end portions in the width direction of the glass ribbon B. The four conveying rollers 19a disposed on both sides of the glass ribbon B and the two driving rollers 19b that are disposed on the both sides of the glass ribbon B are connected to the four conveying rollers 19a on the both sides of the glass ribbon B. In Fig. 3, the both ends of the drive shafts 18b and 19b are not shown. In Fig. 3, the conveyance rollers 18a and 19a are not limited to the above. For example, the conveyance rollers i8a and 19a may be located in the same manner. The same side of the glass ribbon B is not connected to each other by the drive shaft, but with 163507.doc •21-201247566 Similarly, the rolls of 17 are independently disposed at both end portions in the width direction of the glass ribbon 3. In the rapid cooling device 3 for performing the cold cooling step, it is preferable that the temperature of the glass ribbon B is distributed in the width direction to become a mountain peak. Then, the heater or the like disposed around the glass ribbon B is controlled so that the distribution of the mountain peak gradually decreases toward the downstream side in the transport direction. At this time, the temperature near the strain point of the glass ribbon B In the region, it is preferable to control the heater or the like (not shown) so that the distribution of the peaks becomes a flat linear shape, that is, the temperature distribution in the width direction is fixed. In other words, it is cooled from the glass ribbon B. Preferably, the cooling rate of the central portion in the width direction of the glass ribbon is faster than the cooling speed of both ends in the width direction, and the glass is added to the temperature region up to the strain point from the temperature of 15 〇t. The temperature in the central portion in the width direction of the belt B is higher than the temperature at the end portion in the vicinity of the strain point, and the temperature distribution becomes solid. Such a temperature distribution causes the tensile stress to act toward the downstream side in the conveying direction of the glass ribbon. Therefore, the glass ribbon B can suppress the warpage in the conveying direction. Further, since the temperature region in the vicinity of the strain point becomes a uniform temperature distribution, The internal strain can be reduced in the glass sheet. Further, in the temperature at which the temperature of the glass ribbon B becomes (strain point _5〇t > c) from the cold point, it is preferable to slowly compare with other temperature regions. The glass ribbon B is cooled, whereby the heat shrinkage rate of the glass ribbon 8 can be lowered. Further, in the temperature region where the temperature of the glass ribbon B is from the strain point to a temperature obtained by subtracting 200 cm from the strain point, it is preferable that In such a manner that the temperature distribution of the glass ribbon B becomes a valley in the width direction, and the depth of the valley becomes larger as the depth of the valley 163507.doc -22·201247566 is shifted to the downstream side, that is, the temperature of the central portion is increased. The heaters and the like (not shown) are controlled so that the end portions are gradually lowered. In this way, the valley is gradually deepened in the temperature distribution, and the tensile stress is applied to the downstream side in the transport direction. Therefore, the charm of the transport direction can be suppressed. As shown in Fig. 5, the detection control unit 3 includes a computer (not shown) that functions as a conveyance roller state detection unit (hereinafter also referred to as a detection unit) 37 and a speed determination unit 38. Fig. 5 is a block diagram showing the construction of a control system for rotational driving of the pair of feed rollers 18, 19. The detecting unit 37 has a temperature sensor (glass state detecting unit) 3 corresponding to the pair of conveying rollers 18 and 19, and the speed determining unit 38 is connected to the conveying roller pair 8 and the weir 9 via the driving unit 32. The details of the detection control unit 30 will be described later. The drive unit 32 rotationally drives the transport rollers 18a and i9a based on the rotational speeds of the transport rollers 18&, 19a determined by the speed determining unit 38. The drive unit w has a motor (not shown) provided corresponding to each of the transport roller pairs 18 and 19. Further, the motor may not be provided corresponding to each of the pair of conveying rollers 18, 19, and the number thereof may be, for example, less than the number of the pair of conveying rollers 18, 19. In this case, a plurality of conveying rollers 18a and 19a can be driven by one motor by using a gear having a speed ratio change between the respective conveying rollers 18a and 19a. In this case, the driving force from the motor is transmitted to the transport 辋 il 8a, 19a 〇 (detection control unit) via a universal joint or the like, for example, and the detection control unit 30 will be described in further detail. The detection step (step S5 1) performed by the detection control unit 30 is performed as described above in 163507.doc -23-201247566, but the detection step 'may not be performed as described in the following modification. The Xu cold step includes a speed determining step and a speed control step. In this case, the detection control unit 30 is not used. The temperature sensor 34 detects the temperatures of the conveying rollers 18a, 19a. As the temperature sensor 34, for example, a contact type or a non-contact type is used. Here, the detection of the temperatures of the conveyance rollers 18a and 19a also includes calculating the temperatures of the conveyance rollers 18a and 19a. Specifically, each temperature sensor 34 detects the ambient temperature of the arrangement position in the first quenching furnace 12 and the second quenching furnace 13, respectively. Then, the temperatures of the transport rollers 18a and 19a are calculated with reference to the temperature difference data ' stored in the memory unit 36 of the speed determining unit 38 in the detected environmental temperature. The detecting unit 37 calculates the amount of thermal expansion of the transporting members 18a and 19a as a change in diameter based on the detected temperatures of the transporting ports 18a and 19a. The speed determining unit 38 includes a storage unit 36. The memory unit 36 is a memory temperature difference data. The temperature difference data includes data of the difference between the ambient temperature of the quenching furnaces 12 and 13 and the temperature (surface temperature) of the conveying rollers 18a and 19a in each of the environmental temperatures measured in the setting of the cold furnaces 2 and 3. The temperature difference data is memorized differently due to the structure of your furnaces 12, 13. The thermal expansion coefficient of the conveying rollers 18a and 19a (hereinafter also referred to as the coefficient of thermal expansion of the roller) is more stored in the memory unit 36. The coefficient of thermal expansion of the roller is determined by the material of the conveying rollers 18a and 19a. Further, in the memory unit 36, the rotational speed of each of the transport rollers 18a and 19a determined by the speed determining unit 38, the peripheral speed distribution set as a reference between the plurality of transport pro-pairs 18 and 19, and the transport rollers 18a and The reference value of the diameter of 19a. The reference values of the diameters of the respective conveying rollers 18a and 19a are the diameters of the new products at normal temperature (e.g., 25 degrees). In addition, the memory department 36 memory reaches 163507.doc •24·

S 201247566 The conditions for the circumferential speed distribution as the reference (temperature of the conveying roller, temperature of the glass ribbon, thermal expansion coefficient of the glass ribbon, thickness of the glass ribbon, width, flow rate of the glass ribbon, etc.). The speed determining unit 38 sets the peripheral speed between the plurality of conveying roller pairs 18 and 19 when the relative speeds of the peripheral speeds of the conveying rollers 18a and 19a between the plurality of conveying roller pairs 18 and 19 and the conveying speed of the glass ribbon B are fixed. Ratio (circumferential velocity distribution). Next, the speed determining unit 38 determines the respective conveying rollers i8a and 19a so as to maintain the peripheral speed ratio between the plurality of conveying roller pairs 18 and 19 based on the change in the diameter of the conveying rollers 18a and 19a calculated by the detecting unit 37. spinning speed. ((circumferential speed ratio setting)) The peripheral speed ratio between the plurality of conveying roller pairs 18 and 19 is set to 1 (), for example, in such a manner that all of the conveying rollers 18a and 19a have the same circumferential speed. The circumferential speed ratio set as the reference in this manner is the circumferential speed ratio when the cold glass ribbon B is not damaged or the shape is deformed as the circumferential speed distribution of the reference and the temperature of the glass ribbon B. Conditions such as the coefficient of thermal expansion, the thickness, the width, and the flow rate of the glass are collectively stored in the speed determining unit 38. When the circumferential speed ratio is changed as follows when the temperature of the glass ribbon b changes, such as when the temperature changes, the circumferential speed distribution is corrected and set. Further, it is preferable to prevent the "transition of the glass ribbon B" from the transfer rollers 18 & and l9a from the viewpoint of the monthly shift, and the transfer speed of the glass ribbon B between the plurality of transport roller pairs 丨8 and 丨9. The relative speed to the peripheral speed of the conveying roller 18a' 19a is 〇. 163507.doc -25- 201247566 Further, the speed determining unit 38 corrects the circumferential speed ratio of the setting reference by the temperature of the glass ribbon B, the coefficient of thermal expansion, the thickness, the flow rate of the glass, and the like. Specifically, the temperature as a reference for each of the transport roller pairs is set as the condition at the circumferential speed ratio set as the reference circumferential speed distribution. Therefore, when the temperature of the current glass ribbon B changes with respect to the temperature as the reference, for example, when the temperature is changed to the temperature of 2, the speed determining unit 38 uses the thermal expansion coefficient in the temperature difference between the butyl 2 and the dicing The difference is corrected by the circumferential speed ratio set as the reference circumferential speed distribution. The reason for this is that the conveying speed of the glass ribbon B changes due to the thermal expansion coefficient determined by the temperature of the glass ribbon 3 and the coefficient of thermal expansion. In this case, since the coefficient of thermal expansion differs depending on the type of the glass ribbon B, the circumferential speed ratio can be more commonly corrected by taking into consideration the difference between the thermal expansion coefficient of the glass ribbon b and the thermal expansion coefficient of the temperature. Such a peripheral speed ratio is corrected and set not only according to the temperature dependence of the temperature and thermal expansion coefficient of the glass ribbon B but also by changes in the thickness, width, and glass flow weight of the glass ribbon B. Therefore, the conditions of the temperature dependence of the temperature of the glass ribbon B, the temperature dependence of the thermal expansion coefficient, the thickness ratio of the thickness, the width, and the glass flow rate are preliminarily stored in the speed determining unit 38. The coefficient of thermal expansion of the glass is determined by the composition of the molten glass. Based on the set peripheral speed ratio, the peripheral speed of each pair of transport rollers on the downstream side is calculated based on the current peripheral speed of the most upstream transport roller pair. In this manner, the rotational speed of the more appropriate transport rollers 18a, 19a can be determined by correcting the peripheral speed ratio corresponding to the change in the state including the temperature of the glass ribbon B. 163507.doc *26·201247566 (Determining the rotation speed of the conveyance roller) The speed determination determines the rotation speed of each of the conveyance rollers 18a and 19a based on the calculated circumferential speed of each of the conveyance rollers 18a and 19a. Rotation speed = circumferential speed / (diameter of the conveyance roller after thermal expansion χ π) Here, the ambient temperature detected at the arrangement position of each of the conveyance roller pairs 18 and 19 in the cold furnaces 12 and 13 is relative to the above-mentioned peripheral speed as a reference When the temperature of the pair of conveyance rollers is changed, the rotation speeds of the conveyance rollers 18a and i9a are determined so as to maintain the circumferential speed ratio. Specifically, the detecting unit 37 of the conveying rollers 18a and 19a' detecting the temperature change detected by the temperature sensor 34 refers to the thermal expansion coefficient of the rollers in the temperatures of the conveying rollers 18a and 19a, and the reference of the diameters of the respective conveying rollers 18a and 19a. The value of the amount of expansion (the amount of change in diameter) of the conveying roller 18a was calculated according to the following formula. dD=p-DAT dD : expansion amount β : thermal expansion coefficient D: reference value of the diameter of the conveyance roller AT: temperature difference speed determination unit 38 based on the temperature of the conveyance roller set in the reference peripheral speed ratio is based on the detection unit 37 The amount of change in the straight diameter of the conveyance roller 18a is calculated by the following equation, and the amount of change in the circumferential speed is 1, and a new rotation speed is calculated to change the rotation speed of the conveyance rollers 18a and 19a. The new rotation speed = (circumference speed + change amount of the peripheral speed) / ((the diameter of the conveyance roller + the amount of change in the diameter of the conveyance light) χ π) The rotation speed determined by the speed determination unit 38 is conveyed to the drive unit 32, and is controlled. 163507.doc -27- 201247566 The rotation of the conveying rollers 18a, 19a. Further, the computer (not shown) automatically controls the inside of the quenching furnaces 12 and 13 in such a manner that the ambient temperatures in the quenching furnaces 12 and 13 are maintained within a specific temperature range based on the ambient temperature detected by the temperature sensor 34. Heating mechanism. The specific temperature range of the first quenching furnace 12 is set to, for example, 5 〇〇 to 8 〇〇. The specific temperature range of the second quenching furnace 13 is set to, for example, 2 〇〇 to 5 〇〇. Even if the ambient temperature in the quench ovens 12, 13 is controlled in this manner, the temperature of the glass ribbon B or the temperature of the conveying rollers 183, 19a changes as described above. However, since the change is relatively small, even if the peripheral speed ratio as the reference is corrected corresponding to the temperature, the correction amount is small, and the distribution of the peripheral speed ratio as the reference for setting is not largely changed. Further, the speed determining unit 38 can determine the rotational speed of the transport rollers 18a and 19a based on the contents input by the operator. In this case, the glass sheet manufacturing apparatus 1 further includes an input unit (not shown) that accepts an input operation by an operator, and the input unit receives the rotational speeds of the transport rollers 18 & 19 & The memory unit 36 may not memorize the temperature difference data, the roller thermal expansion coefficient, the circumferential speed distribution, the reference value of the diameters of the respective conveying rollers 18a and 19a, the conditions at which the circumferential speed distribution as the reference is obtained, and the like, as long as the memory is based on the temperature difference by the operator. The data, the coefficient of thermal expansion of the roll, the circumferential speed distribution, the reference value of the diameter of each of the transport rollers 18a and 19a, the condition at which the circumferential speed distribution is determined as a reference, and the like may be calculated and input. The isothermal temperature data, the roller thermal expansion coefficient, and the circumferential speed distribution 'the reference values of the diameters of the respective conveying rollers 18a and 19a, and the circumferential velocity distribution as the reference can be calculated by the operator, and the calculated values can be stored in the memory unit 36. 163507.doc • 28-201247566 The panel device 4 includes a panel (not shown) disposed on the downstream side of the second quenching furnace 13. In the paneling room, the glass ribbon B is cut into each fixed length, and the panel is obtained to obtain a glass plate c. The thickness of the glass plate c is, for example, 〇 7 mmW or less than 0.5 mm. Further, since the flat panel display has been required to be thinner in recent years, a glass substrate for a flat panel display such as a liquid crystal display or an organic EL display is required to be thinned. On the other hand, since the thickness of the glass sheet is thinner, the strength of the glass sheet is lowered, so that damage is likely to occur. In consideration of the above, the thickness of the glass plate for a flat panel display is preferably 〇〇1 to 1 mm, more preferably 〇.05 to 0 7 mm, and further preferably 〇5 to 〇5 claws. Further, since the thinner glass plate is used, the strength is lowered, so that it is easily broken due to damage caused by slippage between the roll of the glass ribbon and the glass ribbon. That is, as described above, the actual shape of the slip between the roll and the glass ribbon can be suppressed, for example, it is suitable for the manufacture of a glass plate of 5 to 0.7 mm, and is particularly suitable for the manufacture of a thin plate glass of 0.05 to 0.5 mm. . Further, for example, the length of the glass plate C in the width direction may be 1000 mm or more, 1500 mm or more, 2000 mm or more, 2500 mm or more, and the length in the longitudinal direction may be 1000 mm or more, 15 mm or more, or 2000 mm or more. , 2500 mm or more. As the glass plate c is increased in size, it is easier to cause a relative speed difference (slip) between the glass sheets c and the respective conveyance lamps 18a and 19a due to the weight of the glass ribbon. Therefore, when the length of the glass sheet C in the width direction is 1000 mm or more, the above-mentioned relative speed difference tends to occur, but the effect of preventing the above-described relative speed difference becomes apparent. The length of the sheet C in the width direction is 1500 mm or more, 2000 mm or more, and 2500 mm or more. The effect of the present invention is more advantageous. 163507.doc •29·201247566 (Composition of a glass plate) The glass plate manufactured by the glass plate manufacturing method and the glass plate manufacturing apparatus is preferably a glass substrate for liquid crystal displays, for example. The glass composition of the glass substrate for a liquid crystal display can exemplify the following glass composition. Preferably, it contains:

Si02 50~70 quality. /〇, b2〇3 〇~15% by mass,

Al2〇3 5 to 25% by mass,

MgO 0~1〇% by mass,

CaO 〇~2〇% by mass,

SrO 〇~2〇% by mass,

BaO 〇~1〇% by mass, R0 5~2〇% by mass (wherein R is at least one selected from the total components contained in the glass sheets of Mg, Ca, Sr and Ba). Further, from the viewpoint of suppressing the destruction of a TFT (Thin Film Transistor') formed on a glass substrate for a liquid crystal display, it is preferable to have no glass (substantially free of alkali-containing glass). On the other hand, in order to improve the refining property and the clarification property of the molten glass, it may be made to contain a minute amount of the component. In this case, it is preferred that R'O exceeds 〇.〇5 mass ❶/❶ and is 2.0 mass%/〇 or less, more preferably Rio exceeds 〇1 mass% and is 2% by mass or less (wherein R· is The total composition contained in the glass plate selected from the group consisting of Li, Na, and lanthanum is at least i). According to the glass sheet manufacturing apparatus 1 constructed as described above, it is considered to generate 163507.doc • 30-

S 201247566, the diameters of the conveying rollers 18a and 19a are changed, and the rotation speed of each of the conveying rollers 18a and 19a is controlled so as to compensate for the change in the diameter. Therefore, the peripheral speed of each of the conveying rollers 18a and 19a can be suppressed with higher accuracy. The relative speed of the transport speed of the glass ribbon B is different between the plurality of transport roller pairs 18, 19. Thereby, the slip between the glass ribbon B and the conveying rollers 18a and 19a can be prevented, thereby improving the quality of the surface of the glass sheet. • Moreover, since the circumferential speed distribution of the plurality of conveying roller pairs for conveying the glass ribbon is corrected and set according to the temperature of the glass ribbon, the glass ribbon residual can be prevented from causing deformation of the glass ribbon, and can be made more demanding Fast, and prevent the glass ribbon from being stretched, causing the glass ribbon to break. The effect is such that when the conveying speed of the glass is fast (for example, when the conveying speed is 2 〇〇m/above), or the strength of the glass ribbon is small, the thickness is easily 变形5 mm or less, preferably 〇.〇5~〇.5 mm of thin sheet glass is more obvious in the manufacture. Further, the number of the plurality of conveying roller pairs is at least two, and there is no particular limitation. Further, the above example is for detecting the temperature of the glass ribbon and the temperature of the conveying roller by using the ambient temperature in the temperature sensor of the quenching furnaces 12 and 13, but the glass ribbon temperature and the conveying roller temperature can be directly measured. For this reason, for example, a radiation thermometer for continuously measuring the temperature of the glass ribbon can be used as the glass state detecting portion, and a thermometer for continuously measuring the temperature of the conveying roller can be used as the conveying roller state detecting portion. The peripheral speed ratio is not limited to the above. Further, the speed determining unit 38 can calculate the specific peripheral speed of each of the transport rollers 18a and 19a as the peripheral speed score I63507, doc -31 - 201247566, and replace the ai weekly speed. In this case, the circumferential speed distribution of the material reference and the corrected circumferential speed are also set to specific speed values. In the present embodiment, the rotational speed is adjusted not only in accordance with the change in the diameter of the transport roller so as to reach the set circumferential velocity distribution, but also in the circumferential speed distribution, the circumferential speed distribution as the reference is corrected based on the temperature of the glass ribbon. However, it is also possible to correct the circumferential speed distribution as a reference without depending on the current temperature of the glass ribbon. However, in terms of producing a glass sheet excellent in surface quality, it is preferred to adjust the circumferential speed as a reference based on the current temperature correction of the glass ribbon. (Modification of the first embodiment) In the first embodiment, the rotation speed of the conveyance rollers 18a and 19a is determined so as to compensate for the change in the diameter of the conveyance rollers generated in the respective rollers of the conveyance roller pairs 18 and 19. (4) In addition to 19a, it is also possible to compensate for the change in the diameter of each of the rolls of the pair of rolls 17 used as the pair of cooling rolls in the forming step, and determine the rotational speed of each of the rolls of the light pair 17. The detection unit such as the conveyance roller state detecting unit 37 is used to detect the state of each roller of the roller pair 7 and the diameter of each roller of the roller pair 17 is changed based on the detection result. The rotation speed of each roller of the pair of rollers 17 is determined. In general, since the circumferential speed of each roller of the pair of rollers 7 is set to an appropriate value such that the thickness distribution of the glass sheet or the unevenness of the glass surface is minimized, the deviation from the value causes the thickness distribution of the glass sheet. Or the unevenness of the surface of the glass is deteriorated. That is, if the peripheral speed of the pair of rolls 17 is changed, the amount of stretching of the glass ribbon B between the lower end of the formed body 1〇 between the pair of rolls 17 and the self-rolling pair 17 are moved.

163507.doc ^2 S 201247566 The amount of stretching of the glass ribbon B between the pair of rollers 18 is changed. (Because of the lower end of the formed body 1 , the temperature distribution in the width direction of the 17 strips B is The thickness of the glass ribbon of the pair of conveying rollers 18 and 19 is different in the width direction of the conveying belt). Therefore, the thickness distribution in the width direction of the glass sheet to be produced or the size of the unevenness of the glass surface is changed. Therefore, it is preferable to determine the rotational speed of each of the rollers of the light pair 17 in such a manner as to compensate for the change in the diameter of each of the rollers of the pair of rollers 17. Further, in the present modification, in addition to the lightness of the conveyance reports 18 and 19, the rotation speed is determined by compensating for the diameter change of each of the rollers 17 serving as the pair of cooling rollers in the forming step, but it is also possible At least one of the rollers of the transport roller pair 丨8, Μ and the pair of rollers 17 determines the rotational speed in such a manner as to compensate for the change in the diameter of each roller. In other words, the rotation speed of the roller can be determined so as to compensate for the change in the diameter of the cooling roller or the conveying roller, and it is not necessary to perform the roller only for all the rollers (cooling roller, conveying roller). For example, the rotation speed of the conveyance roller can be determined by compensating for the change in the diameter of the conveyance roller in the region where the center portion of the glass ribbon B is at a softening point (the temperature at which the viscosity η becomes l〇gT1==7.65). Further, the conveyance roller is rotationally driven to suppress the slip of the glass ribbon B or the like, thereby suppressing damage on the surface of the glass ribbon B. If the glass is at least the softening point, the glass ribbon B is not sufficiently cured, so that slippage is less likely to occur. On the other hand, the glass ribbon 3 below the softening point becomes liable to cause slippage. Therefore, it is preferable to determine the rotation speed of the conveyance roller so as to compensate for the change in the diameter of the conveyance roller provided in the region where the center portion of the glass ribbon B is below the softening point, 163507.doc • 33 - 201247566. Further, in the above-described cold cooling step, the rotation of the conveying roller is determined so as to compensate for the change in the diameter of the conveying roller in the temperature region at least the glass transition point and the softening point or lower in the central portion of the glass ribbon B. The speed, therefore, the effect of suppressing the plastic deformation of the glass ribbon B becomes large. Therefore, it is preferable to determine the rotational speed of the transport roller by compensating for the change in the diameter of the transport roller in the temperature region where the temperature at the central portion of the glass ribbon 5 is equal to or higher than the glass transition point and below the softening point. Further, since the conveying roller provided in the central portion of the glass ribbon B reaches a temperature higher than the glass transition point and below the softening point, the diameter of the conveying roller is likely to change. Therefore, it is preferable to compensate the conveying roller provided in the region. The way in which the diameter changes 'determines the rotation speed of the conveying roller. When the glass temperature is higher than the softening point, since the compressive stress acting on the glass is instantaneously relieved, the plastic deformation of the waveform is less likely to occur in the glass ribbon B. On the other hand, when the glass temperature is lower than the glass transition point, since the viscosity of the glass ribbon 3 is sufficiently increased, plastic deformation of the waveform is less likely to occur. Further, the more the transfer roller on the upstream side, the more likely the roll diameter changes due to abrasion or thermal expansion. That is, it is preferable to determine the rotation speed of the conveyance roller so as to compensate for the change in the diameter of the conveyance roller provided in at least the temperature range of the glass transition point or more and the softening point or less. In addition, the rotational speed of the transporting parent can be determined by compensating for the change in the diameter of the transport roller in the temperature region where the temperature at the central portion of the glass ribbon B is reached from the cold point (strain point _5 〇t). And the above-mentioned transfer pro is rotated 163507.doc -34·

S 201247566 turns to drive and inhibits the plastic deformation of the glass ribbon. As described above, the position of the conveying roller which determines the rotation speed in such a manner that the diameter of the compensation roller changes is different depending on which characteristic of the glass ribbon B is improved. (Second Embodiment) Next, a glass sheet manufacturing apparatus according to a second embodiment of the present invention will be described. Here, the description will be made focusing on differences from the above-described first embodiment. The conveyance roller state detecting unit 37 of the first embodiment includes a temperature sensor 34 that detects the temperature of the conveyance report. However, as shown in FIG. 6, the conveyance roller state detection unit of the second embodiment (hereinafter also referred to simply as detection) The portion 47 includes a distance measuring sensor 44 for detecting the amount of wear of the conveying roller. Fig. 6 is a block diagram showing the configuration of a control system for controlling the rotational driving of the transport roller pair 18, 19 in the second embodiment. Further, in Fig. 6, the elements indicated by the same symbols as in the first embodiment are different from the configurations described in the first embodiment. The distance measuring sensor 44 is provided in plural for each of the conveying roller pairs 18, 19. The distance measuring sensor 44 detects the shaft spacing for driving. The drive shaft spacing means the drive shafts 18b and 19b that connect the conveyance rollers 18a and 19a on the same side as the glass ribbon B, and the drive shafts 18b and 19b that are disposed opposite to the drive shafts 18b and 19b. distance. The pair of conveying rollers 18 and 19 hold the glass ribbon B while the pair of conveying rollers 18a and 19a are biased to each other. Therefore, the amount of wear of each of the transport rollers 18a and 19a is detected by the detecting unit 47 as a result of the amount of change in the roll radius calculated by the following formula as compared with the roll radius of the new product due to the abrasion of the transport rollers 18a and 19a. In this formula, 163507.doc -35 - 201247566 is used to fix the thickness of the glass ribbon B at the position of each of the transport rollers 18a and 19a. Therefore, by measuring the distance between the drive shafts 18b and 19b, the proximate handle is calculated. . Roller radius = (drive shaft interval - glass ribbon thickness) / 2 The speed determining portion 48 of the detection control portion 40 generates compensation for the change in the radius of the transport rollers 18a, 19a due to the abrasion of the detected transport rollers 18a, 19a. The rotational speeds of the transport rollers 18a and 19a are determined such that the circumferential speeds of the transport rollers 18a and 19a deviate from the peripheral speed ratio. In addition, in the second embodiment, the diameters of the conveyance rollers 18a and 19a are changed by the change in the radius calculated based on the state of wear, but they may be combined with the temperatures of the conveyance rollers 18a and 19a used in the i-th embodiment. The state of wear is applied. In this case, the diameters of the conveying rollers 18a and 19a vary depending on the amount of wear and change due to thermal expansion. The rotational speed of the transport rollers 18a and 19a can be calculated by maintaining the peripheral speed of the transport roller that changes in accordance with the diameter change to the peripheral speed ratio. Further, in addition to the change in the diameter of the conveyance marks 18a and 19a, the change in the conveyance speed of the glass ribbon B in accordance with the temperature change of the glass ribbon B caused by the thermal expansion of the glass ribbon B can be comprehensively applied as the state of the glass ribbon. According to the second embodiment described above, it is possible to compensate for the deviation of the circumferential speed of the conveying roller from the circumferential speed ratio caused by the change in the diameter caused by the abrasion of the conveying rollers 18a and 19a. Further, in the glass sheet manufacturing apparatus, the distance measuring sensor 44 may read the deviation of the driving shafts 18b and 19b of the pair of conveying rollers 18 and 19 from the origin position, instead of the pair of conveying rollers 18, The driving shafts 18b, 19b of 19 are spaced apart from each other to detect the amount of wear. The origin position conveyance rollers 18a and 19a are

163507.doc -36- S 201247566 The center position of the drive shafts 18b, 19b at the time of the new product, and is stored in the memory unit 46. The deviation between the driving axes i8b and i9b of the pair of conveying rollers 18 and 19 and the origin position is detected, and the amount of wear of the conveying rollers 18a and 19a is detected, whereby the diameter of the worn conveying roller can be calculated. Further, the diameters of the conveying rollers 18a and 19a are not limited to the detection unit 47, and may be calculated by the operator based on, for example, the amount of wear. In this case, the rotation speed of the conveyance rollers 18 and 19a is calculated by the speed determination unit 48 based on the diameters of the conveyance rollers 18a and 19a which are calculated by the operator and input to the speed determination unit 48. Alternatively, the rotation speeds of the conveyance rollers 18a and 19a can be further calculated based on the diameters of the conveyance rollers 18a and 19a calculated by the operator, and the calculation result can be input to the speed determination unit 48. The speed of the nose or the input of the speed determining unit 48 is determined by the speed determining unit 48 and transmitted to the driving unit 32. Further, the amount of wear and the position of the origin of the transport rollers 18a and 19a can be calculated by the operator, and the calculated value can be stored in the memory unit 46. (Variation of the second embodiment) Instead of the second embodiment, a device for counting the change in the diameter of the transport roller calculated based on the number of days of use of the transport rollers 18a and 19a as the change in the diameter of the transport rollers 18a and 19a may be used. The distance measuring sensor 44 of the glass plate manufacturing apparatus. For example, the device for counting the change in diameter conveys the number of days of use of the transport rollers 18a and 19a to the speed determining portion 48. The speed determining unit 48 refers to the memory unit 46 stored in the speed determining unit 48, and the respective conveying rollers 18a and 19a are used as the grinding amount of the conventional replacement performance when the roller diameter is replaced with the new product, and until the replacement. The number of days of use is used, and based on these, the amount of wear per day is calculated. Next, referring to the pro-diameter of the new product in the memory section 163507.doc • 37- 201247566 46, the diameter is calculated according to the following formula. In this case, the number of days of use of the apparatus for counting the change in diameter is not as follows, and the product of the amount of wear per day/the number of days of use corresponds to the amount of wear of the conveyance rollers 18a and 19a. Roll diameter = diameter at the time of the new product _ (the amount of wear per day 乂 the number of days of use) The speed determining unit 48 is attached to the storage unit 46, and remembers the previous transfer performance and new products for each of the transfer rollers 19, 19& Roll diameter. According to this modification, it is possible to compensate for the deviation of the circumferential speed of the conveying rollers 18a and 19a caused by the change in the diameter of the conveying roller 18a1 by the simpler method. Further, the amount of wear per day can also be The operator calculates and memorizes it in the memory unit 46. Further, the diameter change of the conveyance rollers 18a and 19a caused by the above-described wear amount can be calculated by the operator and transmitted to the detection control unit 40 or the drive unit 32. Further, the amount of wear of the intimate diameter in the conventional replacement and the number of days until the replacement of the new product can be changed by the operator, and the calculated value can be stored in the memory unit 46. As described above, in the present modification, the conveyance rollers 18a and 19a are red-rotated based on the rotation speed determined based on the number of days of use of the conveyance rollers 18a and 19a so as to compensate for the change in the diameter of the compensation roller. The present modification is different from the first embodiment in that the first embodiment and the second embodiment are different in that the number of days of use of the transport pro iga and i9a is determined sequentially, and the rotation speed is not determined as described in the first embodiment and the second embodiment. 'The conveyance roller state detecting unit detects the state of the conveyance roller, and determines the roller rotation speed based on the detection result'. Furthermore, the first embodiment or the modification of the first embodiment and the second embodiment 163507.doc

The modification of the S-38-201247566 embodiment or the 谏2 embodiment may be combined. By combining the modification of the first embodiment or the first embodiment with the modification of the second embodiment or the second embodiment, the modification of the third embodiment or the first embodiment or the 2 Compared with the case of the modification of the second embodiment, the deviation from the peripheral speed ratio is compensated with higher accuracy. (Examples) In order to investigate the effects of the present invention, the glass ribbon manufacturing apparatus of the present embodiment and the glass sheet manufacturing apparatus of the present embodiment were used to produce a glass ribbon ′ according to the following method, and the undulation of the undulations generated in the glass ribbon was measured. . Further, the glass plate manufacturing apparatus used is a glass plate manufacturing apparatus 1 of the lower drawing method shown in Figs. 3 and 4, and an aluminosilicate glass containing the components shown below is used.

Si02 60% by mass,

Al2〇3 19.5 mass%, b2o3 10 mass%,

CaO 5 mass%,

SrO 5 mass%,

Sn02 0.5% by mass. In the first embodiment, the speed determining unit 38 determines the rotational speed of each of the transport rollers 18a and 19a, and controls the rotational driving of the transport rollers 18a and 19a based on the determined rotational speed. 7.7 mm thickness Manufacture of a glass substrate for a liquid crystal display having a length of 2000 mm in the width direction and a length of 2500 mm in the longitudinal direction. The circumferential speeds of the respective conveying rollers 18a, 163507.doc - 39 - 201247566 19a which are circumferential speed ratios are the same. The temperature of the glass ribbon and the temperature of the transfer roller were measured using a contact type temperature sensor. In the second embodiment, a glass substrate for a liquid crystal display is produced in the same manner as in the first embodiment except that the rotation speed of each of the conveyance marks iga and i9a is determined by the speed determining unit 48. Specifically, the amount of wear of the conveyance rollers 18a and 19a is calculated by the drive shaft interval measured by the distance measuring sensor 44. In addition, the amount of change in the diameter of the roller caused by the amount of wear of the conveying rollers 18a and 19a is considered, and the rotational speed of the conveying rollers 18a and i9a is calculated in consideration of the amount of change in the diameter of the roller caused by the temperatures of the conveying rollers 18a and 19a. In the third embodiment, the circumferential speeds of the respective transfer rollers 18a and 19a are changed to one-to-one times that of the first embodiment, and the glass for a liquid crystal display having a thickness of 0.5 mm is produced in the process of determining the rotational speed of the transport rollers 18a and 19a. A glass substrate for a liquid crystal display was produced in the same manner as in Example 1 except for the substrate. In Comparative Examples 1 and 2, the control of the rotation speed of the state of the glass ribbon and the change of the diameter of the conveyance rollers 18a and 19a was not performed in the speed determination unit, and the conditions were the same as those of the first and second examples. . With respect to the obtained glass substrates for liquid crystal displays of Examples 1 to 3 and Comparative Examples 1 and 2, the surface of the glass substrate for liquid crystal display was visually observed to have no damage, and the waveform was measured by a thickness gauge. The waveform was deformed in a glass substrate for a liquid crystal display having a thickness of 0.7 mm, and the surface quality was set to be within 0.4 mm in the thickness direction. For glass substrates for liquid crystal displays with a thickness of 〇 5 mm, set 〇2 mm in the thickness direction to 163507.doc •40-

S 201247566 Meets surface quality. The glass substrates for liquid crystal displays of Comparative Examples 2 and 2 obtained by the prior art manufacturing apparatus were visually confirmed to have damage on the glass surface. Further, deformation of a waveform of 0.5 mm in the thickness direction is generated. On the other hand, in the glass substrate for liquid B 曰 display of Example 13 obtained by the production apparatus of the present embodiment, the damage was not visually observed on the surface of the glass. Further, in the case of "deformation of the waveform", the first embodiment produced a deformation of about 〇 2 mm in the thickness direction. In the second embodiment, deformation in the thickness direction of about 1 mm was produced. In the third embodiment, the deformation in the thickness direction is 〇 〇 2 瓜山. Each of Examples 1 to 3 satisfies the above surface quality. In the above, the glass sheet manufacturing method and the glass sheet manufacturing apparatus of the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and it is needless to say that it can be carried out without departing from the spirit of the invention. Various improvements or changes. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an example of a flow of a method for producing a glass sheet according to the present embodiment. Fig. 2 is a view showing an example of the flow of the cold step. Fig. 3 is a plan view showing the inside of a glass sheet manufacturing apparatus according to a first embodiment of the present invention. Figure 4 is a cross-sectional view of the arrow line of the IV line of Figure 3. Fig. 5 is a block diagram showing the configuration of a control system for controlling the rotational driving of the pair of conveying rollers. Fig. 6 is a block diagram showing the configuration of a control system for rotational driving of a transport roller pair according to a control unit of a glass sheet manufacturing apparatus according to a second embodiment of the present invention. 163507.doc • 41 · 201247566. [Description of main component symbols] 1 Glass plate manufacturing apparatus 2 Forming device 3 Pressing device 4 Cutting device 10 Molded body 10a Groove 11 Furnace chamber 12 First cold furnace 13 Second cold furnace 15 Furnace wall 16 Transfer hole 17 Roll pair 18, 19 Transfer roller pair 18a, 19a Transport roller 18b, 19b Drive shaft 21 to 23 Heat shield 30 Detection control unit 32 Drive unit 34 Temperature sensor (glass state detecting unit) 36 Memory unit 37 Transport roller state detecting unit 38 Speed determination 163507.doc •42- 201247566 40 Detection control unit 44 Distance measurement sensor 46 Memory unit 47 Transport roller state detection unit 48 Speed determination unit A Molten glass B Glass ribbon C Glass plate IV line S10 Melting step S20 Clarification step S30 Stirring Step S40 Forming Step S50 Thawing Step S51 Detection Step S52 Speed Determination Step S53 Speed Control Step S60 Panel Step S70 Shape Processing Step 163507.doc -43-

Claims (1)

201247566 VII. Patent application scope: ι_ - A method for manufacturing a glass plate, characterized by comprising: a melting step of melting a glass raw material to produce molten glass; and a forming step of forming a molten glass by using a down-draw method to form a glass ribbon And a cold step of tempering the glass ribbon by a plurality of rollers disposed along a direction in which the glass ribbon is conveyed and dragging downward; and the forming step comprises: arranging the glass ribbon on one side by a roller pair a step of cooling the both ends of the glass ribbon while holding it downward, and at least one of the pair of rollers used in any one of the forming step and the quenching step is a pair of rollers Each of them is lightly driven based on the rotational speed of the roller of the shirt in such a manner as to compensate for the change in the diameter of the roller. A method for producing a glass sheet, comprising: a melting step of melting a glass raw material to produce a molten glass; and a forming step of forming a glass ribbon by using a down-draw method to form a glass ribbon; and "Xu cold step", which uses the plurality of rollers disposed in the direction in which the glass ribbon is transported by the sloping slope, and the locating hole is pulled downward to perform the cold cooling; and the above-mentioned cold cooling step In the above roller pair, at least one of the pair of rollers, that is, each roller of the first roller pair, is rotationally driven based on the rotation speed of the roller determined by the diameter change of the complementary roller. 3. The garment of the glass sheet of claim 1 or 2, wherein the above-mentioned cold cooling step 163507.doc 201247566 includes: a detecting step of detecting the above-mentioned first and second directions by the glass ribbon detecting portion Going to "the diameter change of each roller of the first roller pair; and 々 & /, based on the detected first roller pair, ten. the diameter change of each roller, also - the above-mentioned _th Each of the rotation speeds of the respective rotations, and the above-mentioned 4. The broken glass 'Hungry Ilk method' of the claim 1 or 2, wherein each of the roller systems of the first roller is disposed at least the above-mentioned cold step The temperature in the center of the glass ribbon is in the temperature region above the glass transition point and below the softening point, and in the above-mentioned cold cooling step, the above-mentioned i-th light pair is determined by compensating for the lightness of the above-mentioned old pair. The light-rotating speed of each of the first roller pairs is rotatably driven. 5. The method of manufacturing the glass sheet of claim 2, wherein in the forming step and the quenching step, the glass is The temperature in the center of the belt is glass In the region above the softening point of the glass, the end portion of the glass ribbon in the width direction is controlled to be lower than the temperature of the central region sandwiched by the end portion, and the temperature of the central region is substantially uniform, and the glass ribbon is controlled. The temperature in the central portion is controlled in a region where the softening point is not higher than the strain point, and the tensile stress in the transport direction acts on the central portion of the glass ribbon to control the temperature in the width direction of the glass ribbon. From the central portion of the glass ribbon toward the end portion, and in the temperature region near the glass strain point of the glass ribbon, the temperature gradient between the end portion and the central portion of the width direction of the glass ribbon is described above. 6. The method of manufacturing the glass sheet according to claim 1 or 2, wherein in the step of cooling, the temperature in the central portion of the glass ribbon is not near the strain point. In the region, the temperature distribution of the glass ribbon is controlled such that the tensile stress in the conveying direction acts on the central portion of the glass ribbon. The temperature distribution of the glass ribbon is lowered from the end portion in the width direction of the glass ribbon toward the central portion. The method of manufacturing the glass sheet according to claim 1 or 2, wherein the step of cooling comprises: a first cooling step Cooling at the second average cooling rate until the temperature in the central portion of the glass ribbon reaches the freezing point; and in the second cooling step, cooling at the second average cooling rate until the temperature in the central portion is from the above-mentioned cold point Achieving a strain point of 5 〇. 及; and a third cooling step, which is cooled at a third average cooling rate until the temperature of the center Zou reaches the strain point _ 2 〇〇 ° C from the strain point machine; The first average cooling rate is 5 〇〇 c / sec - 8. The first average cooling rate is faster than the third average cooling rate, and the third average cooling rate is faster than the second average cooling rate. The method for producing a glass sheet according to claim 1 or 2, wherein the method of compensating for the deviation of the circumferential speed caused by the change of the lightness of the first and the first light caused by the thermal expansion of each of the first pair of rollers is determined In the above-mentioned W 163507.doc 201247566, the rotation speed of each roller is changed to 0, and the first roller pair is rotated. 9. The manufacturing method of the glass plate of claim 2 or 2, wherein the compensation is made by the above The first i = the rotational speed of each of the first pair of pairs is determined by the difference in the circumferential speed caused by the change in the diameter of each of the first roller pairs caused by the abrasion of each of the first roller pairs Each roller of the roller pair is rotationally driven. 10. The method of producing a glass sheet according to claim 1 or 2, wherein the plurality of pairs of rolls have a pair of rolls that are rotationally driven based on a rotation speed of the stick determined by compensating for a change in diameter of the roll, The second roller pair is included in addition to the first roller pair; the method for manufacturing the glass plate includes detecting the first roller pair and the second roller pair by a plurality of detecting portions provided along a conveying direction of the glass ribbon a step of detecting a diameter change of each of the members, wherein a speed at which the circumferential speed of the roller and the conveying speed of the glass ribbon are fixed between the rollers of the first roller pair and the rollers of the second roller pair is fixed It is decided to compensate for the above-mentioned respective rotation speeds of the respective diameter changes. The method for producing a glass sheet according to claim 1 or 2, wherein the temperature of the glass ribbon is detected by a glass state detecting portion which is disposed along a conveying direction of the glass ribbon and detects the state of the glass ribbon; The coefficient of thermal expansion of the glass in the temperature of the glass ribbon 'detects the change in the conveying speed of the glass ribbon caused by the thermal expansion of the glass ribbon' and compensates for the deviation of the conveying speed of the glass ribbon from the circumferential speed of the roller 163507.doc S 201247566 The method 'determines the rotation speed of each of the first roller pairs. 12. The method of producing a glass sheet according to claim 1 or 2, wherein the thickness of the glass sheet obtained by quenching the glass ribbon is 0.5 mm or less. 13. A glass sheet manufacturing apparatus characterized by comprising: a forming apparatus that shapes a glass ribbon from a molten glass using a down-draw method; and a "cold cooling apparatus" that holds the glass ribbon by a plurality of conveyance reports The cold cooling device includes a plurality of conveying roller pairs, a detection control unit, and a driving unit, and the plurality of conveying roller pairs are disposed along the conveying direction of the glass ribbon, and are borrowed The glass ribbon is conveyed by pulling the glass ribbon downward; the detection control unit includes a plurality of conveyance roller state detecting sections that are provided along the conveyance direction of the glass ribbon and that detect a change in the diameter of the conveyance roller of the conveyance roller pair; The driving unit is configured to detect the circumferential speed distribution between the plurality of conveying roller pairs when the relative speed between the peripheral speed of the conveying roller and the conveying speed of the glass ribbon is fixed between the plurality of conveying pairs The rotation speed of each of the conveyance rollers determined by the change in the diameter of the conveyance roller is made to convey the conveyance Rotary drive. 163507.doc