JP2018095518A - Production method of glass article, and release powder spraying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress generation of a defect such as a pit caused by an adhesion state of release powder onto a glass sheet.SOLUTION: A production method of a glass article has an adhesion step S1 for allowing release powder to adhere onto the surface of a crystalline glass sheet, a heating step S4 for heating and crystallizing the glass sheet in the piled state, a deposit rate measuring step S2 for calculating a deposit rate of the release powder by analyzing an image of the surface of the glass sheet after the adhesion step S1, and a determination step S3 for determining whether the deposit rate is within a specific range or not. When determined that the deposit rate is within the specific range, the glass sheet is supplied to the heating step S4.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing a glass article and a mold release device.

  As a method for producing a heat-resistant plate-shaped glass article, a production method is known in which a glass plate formed by roll forming or the like is heated to crystallize (for example, see Patent Document 1).

Japanese Patent Laid-Open No. 11-228180

  In the manufacturing method of said glass article, in order to improve the production efficiency, the process which bakes simultaneously as the state which accumulated the several glass plate is performed. Specifically, mold release powder is made to adhere to one side of a glass plate. As a method for attaching the release powder to the surface of the glass plate, for example, there is a method in which the release powder dispersed in the atmosphere is naturally settled and laminated on the surface of the flat glass plate. Then, a glass plate is placed on the setter for heat treatment with the surface to which the release powder is attached facing downward, and the surface to which the release powder is attached is placed on the lower side of the glass plate. The glass plates are stacked sequentially. And the laminated | stacked several glass plate is baked simultaneously.

  In this case, if the release powder adhered to the surface of the glass plate is insufficient, defects such as welding between the glass plates and pits (transfer marks) may occur. In particular, when the release powder between the heat treatment setter is insufficient, foreign matter existing on the heat treatment setter, or a concave defect caused by the difference in thermal shrinkage between the heat treatment setter and the glass plate (so-called , Pits) are likely to occur.

  Therefore, it is necessary to appropriately manage the amount of the release powder attached to the glass plate. As a method of managing the amount of release powder adhered, there is a method of managing the amount of release powder applied to the glass plate and the time of application, but it is sufficient to adjust the amount of release powder applied and the time of application. Even when a large amount of release powder was sprayed, defects such as transfer marks sometimes occurred.

  The present invention has been made in view of such circumstances, and an object thereof is to suppress the occurrence of defects such as pits due to the state of the release powder adhering to the glass plate.

  A method for producing a glass article for achieving the above object includes an attaching step of attaching a release powder to the surface of a crystalline glass plate, and a heating step of heating and crystallizing the glass plate in a stacked state. A method of manufacturing a glass article having an adhesion rate measuring step of calculating an adhesion rate of a release powder by analyzing an image of the surface of the glass plate after the adhesion step, and the adhesion rate is within a specific range The glass plate is subjected to the heating step when the adhesion rate of the glass plate is determined to be within a specific range.

  The cause of defects such as pits generated when a sufficient amount of release powder is sprayed is due to unevenness in the amount of release powder adhered to the surface of the glass plate. That is, even if a sufficient amount of release powder is adhered, if there is a part where the amount of the release powder is partially attached to the surface of the glass plate, defects such as pits are generated in that part. In addition, as a cause which the nonuniformity in the adhesion amount of mold release powder, environmental factors, such as temperature and humidity, and the mechanical factor by a mold release powder spraying apparatus are mentioned. Therefore, the image of the surface of the glass plate to which the release powder is adhered is analyzed to determine the adhesion rate of the release powder, and based on the adhesion rate, the glass plate to which the release powder is suitably attached is heated. By using this, it is possible to suppress the occurrence of defects such as pits due to the adhered state of the release powder.

  In the method for producing a glass article, the area of the adhesion region of the release powder occupying the surface of the glass plate is calculated as an adhesion rate, and it is determined whether or not the adhesion rate is within a range of 20 to 90%. Is preferred.

In this case, the occurrence of defects such as pits can be suitably suppressed.
In the manufacturing method of the said glass article, it is preferable to have the adjustment process which adjusts the parameter relevant to the dispersion | distribution state of the mold release powder in the said adhesion process based on the said adhesion rate measured in the said adhesion ratio measurement process.

  In this case, it can suppress that the glass plate in which the adhesion rate of a mold release powder does not exist in a specific range is continued in an adhesion process. And the glass plate which has the adhesion rate of mold release powder in a specific range, ie, the glass plate which cannot produce defects, such as a pit, can be produced efficiently. As a result, the production efficiency of the glass article can be increased.

  In the method for manufacturing a glass article, the attaching step sprays release powder from above the glass plate using a release powder spraying device on the glass plate that is continuously conveyed in a flat state. The release powder spraying device is disposed at a position where the release powder is attached to the surface of the supply roller and in contact with the supply roller, and rotates in the opposite direction to the supply roller. And a spray brush roller that scrapes and disperses the release powder adhering to the surface of the supply roller, and the parameter is preferably the rotational speed of at least one of the supply roller and the spray brush roller.

In this case, it is possible to easily adjust the adhesion rate of the release powder.
In the glass article manufacturing method, the adhesion rate measurement step and the determination step are selectively performed on the specific glass plate that has undergone the adhesion step, and the adhesion rate is determined to be within the specific range. In this case, the glass plate that has undergone the attachment step within a predetermined period in which the release powder is dispersed in the attachment step is the same as the glass plate, and the heating step assumes that the adhesion rate is within the specific range. It is preferable to use for.

In this case, the production efficiency of the glass article can be increased as compared with the case where the adhesion rate measurement process and the determination process are performed on all the glass plates that have undergone the adhesion process.
In the manufacturing method of the said glass article, it is preferable to perform the said adhesion process, the said adhesion rate measurement process, and the said determination process with respect to the glass for a test | inspection different from the color tone of mold release powder. Moreover, it is preferable to analyze the image of the surface of the said glass plate in the state which has arrange | positioned the coloring member of the color tone different from the color tone of a mold release powder in the said adhesion rate measurement process in the back side.

  In these cases, in the adhesion rate measuring step, the contrast between the part where the release powder is attached and the part where the release powder is not attached on the surface of the glass plate is clarified, and the process for obtaining the adhesion rate of the release powder is performed. It becomes easy.

  In the manufacturing method of the said glass article, when it determines with the said adhesion rate of the said release powder in the said glass plate being smaller than the said specific range, it implements the process of the said adhesion process again to the said glass plate, In the said glass plate When it determines with the said adhesion rate of the said mold release powder being larger than the said specific range, it is preferable to remove at least one part of the mold release powder of the said glass plate.

  In this case, the release powder is temporarily removed from all the glass plates for which the adhesion rate is determined to be out of the specific range, and the separation process is performed again compared to the case where the adhesion process is performed again. It is possible to efficiently produce a glass plate having a mold powder adhesion rate within a specific range.

  A release powder spraying device for achieving the above-mentioned object is a release powder spraying device for spraying a release powder and attaching the release powder to the surface of a glass plate. A supply roller that rotates in an attached state, and a spray that is arranged at a position in contact with the supply roller and rotates in the opposite direction to the supply roller to scrape and release the release powder adhering to the surface of the supply roller. A brush roller and an auxiliary roller that is disposed at a position in contact with the supply roller on the side where the release powder scraped by the spray brush roller scatters and rotates in a direction opposite to the spray brush roller. And

  According to the said structure, release powder is scattered in the range of the downward side of a spreading | diffusion brush roller, and scattering of the release powder to the range which is not intended other than that is suppressed. Thereby, unevenness is hardly generated in the amount of the release powder adhering to the surface of the glass plate, and the occurrence of defects such as pits due to the uneven amount of the release powder adherence can be suppressed. Moreover, it is suitable as a mold release powder dispersion apparatus used for the manufacturing method of the said glass article.

  According to this invention, generation | occurrence | production of defects, such as a pit resulting from mold release powder, can be suppressed.

The flowchart of the manufacturing method of a glass article. Explanatory drawing of an adhesion process. Explanatory drawing of a mold release powder spraying apparatus.

[First embodiment]
The first embodiment of the present invention will be described below.
As shown in FIG. 1, the manufacturing method of the glass article of 1st Embodiment is the adhesion process S1 which makes mold release powder adhere to the surface of a glass plate, and the adhesion which measures the adhesion rate of mold release powder on the surface of a glass plate A rate measuring step S2, a determining step S3 for determining whether or not the adhesion rate is within a specific range, and a heating step S4 for heating the glass plate. Hereinafter, each step will be specifically described.

(Adhesion process)
Adhesion process S1 is a process which makes mold release powder adhere to the surface of a glass plate. The glass plate used for the adhesion step S1 is a crystalline glass plate that is crystallized by heating to become crystallized glass. For example, Li ₂ containing TiO ₂ or P ₂ O ₅ as a crystal nucleating agent. O—Al ₂ O ₃ —SiO ₂ crystalline glass. As the crystalline glass plate, a glass plate formed by a known method such as roll forming can be used. Moreover, as the release powder, a powdery substance having at least one of cleavage property and cleavage property is preferably used. Specific examples of the release powder include talc and alumina. Moreover, it is preferable that the average particle diameter of mold release powder exists in the range of 1-50 micrometers, and it is more preferable that it exists in the range of 5-15 micrometers.

  As shown in FIGS. 2 and 3, the attaching step S <b> 1 includes a conveying device 10 that continuously conveys the glass plate G in a flat state, and a release powder spraying device installed above the conveying path of the conveying device 10. 20 is used.

  The release powder spraying device 20 includes an accommodating portion 21 that accommodates the release powder F. A supply roller 22 that is rotatable around an axis extending in the direction orthogonal to the conveyance path and in the horizontal direction is attached to the lower portion of the storage portion 21 with the lower portion exposed from the storage portion 21. On the outer peripheral surface of the supply roller 22, a plurality of recesses 22 a that contain the release powder F are formed. The magnitude | size of the recessed part 22a can be suitably set according to the particle diameter of the mold release powder F, etc. In addition, a pair of scrapers 23 are attached to the lower portion of the accommodating portion 21. The pair of scrapers 23 are disposed at positions where the supply roller 22 is sandwiched therebetween, and are attached in a state where the tip portions thereof are in close contact with the outer peripheral surface of the supply roller 22.

  The supply roller 22 is configured to rotate as indicated by an arrow so that the release powder F accommodated in the recess 22a is scraped off by the scraper 23 and sent to the lower portion of the supply roller 22 exposed from the accommodation portion 21. ing. The supply roller 22 is connected to a first drive unit 24 such as a motor for rotating the supply roller 22.

  The release powder spraying device 20 includes a spraying brush roller 25 that can rotate around an axis extending in the direction orthogonal to the transport path and in the horizontal direction. The spray brush roller 25 is a roller for scraping and scattering the release powder F accommodated in the recess 22 a of the supply roller 22, and is disposed at a position in contact with the supply roller 22. A brush portion 25 a made up of a plurality of linear portions protruding in the radial direction is provided on the outer peripheral portion of the spray brush roller 25. It is preferable that the wire diameter of the linear part which comprises the brush part 25a is 0.01-0.2 mm, for example. In this case, the release powder F can be finely dispersed.

  The spray brush roller 25 rotates in the direction opposite to the supply roller 22 as indicated by an arrow, thereby scraping off the release powder F accommodated in the recess 22a of the supply roller 22, and the spray brush from the contact point with the supply roller 22 The release powder F is scattered to the front side in the rotation direction of the roller 25 (the lower right side in FIG. 2 and FIG. 3). Further, a second drive unit 26 such as a motor for rotating the spray brush roller 25 is connected to the spray brush roller 25. The rotation speed of the spray brush roller 25 is preferably 40 to 400 rpm, for example. In this case, the release powder F can be finely dispersed.

  The release powder spraying device 20 includes an auxiliary roller 27 that can rotate around an axis extending in a direction orthogonal to the conveyance path and in the horizontal direction. The auxiliary roller 27 is a roller for narrowing the scattering range of the release powder F, and on the side where the release powder F scraped out by the spray brush roller 25 is scattered (the lower right side in FIG. 2 and FIG. 3). These are arranged at positions in contact with the spray brush roller 25. Here, as shown in FIG. 3, the distance L1 between the auxiliary roller 27 and the supply roller 22 is between the contact point of the supply roller 22 and the spray brush roller 25 and the contact point of the spray brush roller 25 and the auxiliary roller 27. It is preferable that the distance is shorter than the distance L2. In this case, the effect of narrowing the scattering range of the release powder F is enhanced.

  The auxiliary roller 27 rotates in the direction opposite to the spray brush roller 25 as indicated by the arrow, thereby releasing the release powder F scraped by the spray brush roller 25 and the release powder F adhering to the spray brush roller 25. Further, it is configured to scatter from the contact point with the spray brush roller 25 to the front side in the rotational direction of the auxiliary roller 27 (the lower left side in FIG. 2 and FIG. 3). The auxiliary roller 27 is connected to a third drive unit 28 such as a motor for rotating the auxiliary roller 27.

  Further, the release powder spraying device 20 includes a control unit 29 that controls driving of the first drive unit 24, the second drive unit 26, and the third drive unit 28. The control unit 29 is configured such that the rotation speeds of the supply roller 22, the spray brush roller 25, and the auxiliary roller 27 can be set independently by controlling the driving of each driving unit.

  As shown in FIG. 2, in the adhesion step S <b> 1, the release powder spraying device 20 is driven to spray the release powder F over a specific range in the transport path of the transport device 10, and by the transport device 10, The glass plate G in a flat state is continuously conveyed. Thereby, when the glass plate G passes the lower position of the release powder spraying device 20, the release powder F sprayed from the release powder spraying device 20 adheres to the surface (upper surface) of the glass plate G. In addition, the adhesion amount of the release powder F with respect to the glass plate G can be adjusted by changing the conveyance speed of the conveyance apparatus 10 and the rotational speed of each roller of the release powder spraying apparatus 20.

(Adhesion rate measurement process)
The adhesion rate measurement step S2 is a step of measuring the adhesion rate of the release powder F on the surface of the glass plate that has undergone the adhesion step S1.

  In the adhesion rate measurement step S2, first, an image of the surface of the glass plate G on which the release powder F is adhered in the adhesion step S1 is acquired using an imaging device such as a CCD camera. At this time, when it is difficult to distinguish the surface of the glass plate G itself from the release powder F, for example, when the glass plate G is a colorless and transparent glass plate, the color tone of the release powder F is different. It is preferable to acquire an image of the surface of the glass plate G in a state in which the color tone coloring member is disposed on the back side of the glass plate G. As an example, when the glass plate G is colorless and transparent and the release powder F is white, it is preferable to use a black colored member. In addition, you may acquire the said image by imaging the arbitrary area | regions of the glass plate G. FIG. That is, the entire surface of the glass plate G may be imaged, or a part of the surface of the glass plate G may be imaged. When a part of the surface of the glass plate G is imaged, the position and size of the area to be imaged may be arbitrarily determined. For example, a range of 2 cm × 2 cm square may be imaged.

  Next, the obtained image is binarized based on the contrast between the color tone of the glass plate G (color tone of the coloring member) and the color tone of the release powder F. Then, while analyzing the said image, while calculating | requiring the area (attachment area) of the part (attachment area | region of the release powder F which occupies for the surface of the glass plate G) covered with the release powder F in the surface of the glass plate G The adhesion rate calculated as a ratio of the adhesion area to the surface (upper surface) of the glass plate G is obtained. In addition, about an adhesion area, a line is drawn along the outline of the mold release powder F with respect to the binarized image, and the area surrounded by the line is defined as the area of the portion covered with the mold release powder F. Can be sought.

(Judgment process)
Judgment process S3 is a process of judging whether the adhesion rate of mold release powder F is in a specific range. In determination process S3, when it determines with the adhesion rate of mold release powder F being in a specific range, the said glass plate G is used for the subsequent heating process. Moreover, when it determines with the adhesion rate of the mold release powder F being outside a specific range, the said glass plate G is excluded from the glass plate G which uses for a heating process. As said specific range, it is preferable that it is 30 to 90%, for example. In this case, the occurrence of defects such as pits due to the release powder can be suitably suppressed.

  In the present embodiment, the adhesion rate measurement step S2 and the determination step S3 are selectively performed on a part of the glass plate G that has undergone the adhesion step S1. In this case, for example, the spraying state of the release powder F in the adhesion step S1 adheres within a predetermined period (for example, a predetermined time or a predetermined number of sheets) that is the same as the glass plate G subjected to the adhesion rate measurement step S2 and the determination step S3. The adhesion rate of the glass plate G that has been subjected to the adhesion rate measurement step S2 and the determination step S3 is applied to the glass plate G that has undergone the step S1. Specifically, when it is determined that the adhesion rate of the glass sheet G on which the adhesion rate measurement step S2 has been performed is within a specific range, the dispersion state of the release powder F in the adhesion step S1 is the adhesion rate measurement step S2 and the determination. The glass plate G that has undergone the adhesion step S1 within the predetermined period that is the same as the glass plate G that has undergone the step S3 is also considered to be within a specific range and subjected to the subsequent heating step.

(Heating process)
The heating step S4 is a step of crystallizing by heating and baking the glass plates G in a stacked state. In the heating step S4, the glass plate G is placed on the setter for heat treatment with the surface on which the release powder is attached facing downward, and the release powder F is also attached on the glass plate G. The glass plates G are sequentially stacked with the formed surfaces facing downward. And the several glass plate G piled up is baked using a well-known heating apparatus (for example, roller hearth kiln). By this firing, the glass plate G becomes crystallized glass. The obtained crystallized glass is subjected to a cooling treatment and then separated one by one and used as a glass article. In addition, when isolate | separating heat resistant crystallized glass, glass can be easily isolate | separated by the release powder F interposing between the laminated | stacked glass plates G. FIG.

Next, operations and effects of the first embodiment will be described.
(1) The method for producing a glass article includes an adhesion step S1 for attaching the release powder F to the surface of the crystalline glass plate G, and a heating step S4 for heating and crystallizing the glass plate G in a stacked state. Have. Further, an adhesion rate measurement step S2 for analyzing the image of the surface of the glass plate G after the adhesion step S1 to calculate the adhesion rate of the release powder F, and a determination for determining whether or not the adhesion rate is within a specific range When it has been determined that the adhesion rate is within a specific range, the glass plate G is subjected to the heating step S4.

  The cause of defects such as pits generated when a sufficient amount of release powder F is sprayed is unevenness in the amount of the release powder F attached to the surface of the glass plate G. That is, even if a sufficient amount of the release powder F is adhered, if there is a portion where the amount of the release powder F is partially attached to the surface of the glass plate G, defects such as that will occur in that portion. . In addition, as a cause which the nonuniformity in the adhesion amount of mold release powder F produces | generates environmental factors, such as temperature and humidity, and the mechanical factor by a mold release powder spraying apparatus are mentioned. Therefore, the image of the surface of the glass plate G to which the release powder F is adhered is analyzed to determine the adhesion rate of the release powder F, and the glass to which the release powder F is suitably adhered based on the adhesion rate By selectively subjecting the plate G to the heating step S4, it is possible to suppress the occurrence of defects such as pits due to the attached state of the release powder F. And it becomes possible to produce with stable quality.

(2) The glass plate G determined to have an adhesion rate in the range of 20 to 90% is subjected to the heating step S4.
According to the said structure, generation | occurrence | production of defects, such as a pit, can be suppressed suitably.

  (3) The adhesion rate measurement step S2 and the determination step S3 are selectively performed on the specific glass plate G that has undergone the adhesion step S1. And when it determines with an adhesion rate being in a specific range, the glass plate G which passed through adhesion process S1 in the predetermined period when the dispersion | spreading state of the mold release powder F in adhesion process S1 is the same as the said glass plate G, It is considered that the adhesion rate is within a specific range and is used for the heating process.

According to the said structure, compared with the case where the adhesion rate measurement process S2 and determination process S3 are performed with respect to all the glass plates G which passed adhesion process S1, the production efficiency of a glass article can be improved.
(4) In the adhesion rate measurement step S2, an image of the surface of the glass plate G in a state where the colored member having a color tone different from the color tone of the release powder F is arranged on the back side is analyzed.

  According to the said structure, the contrast with the part which the mold release powder F has adhered on the surface of the glass plate G becomes clear, and the process which calculates | requires the adhesion rate of the mold release powder F becomes easy. .

  (5) The release powder spraying device 20 used in the attaching step S1 is disposed at a position where the release roller F rotates in a state where the release powder F is attached to the surface and the supply roller 22 is in contact with the supply roller 22. A spreading brush roller 25 that rotates in the reverse direction to scrape and release the release powder F adhering to the surface of the supply roller 22 and a spreading brush on the side where the release powder F scraped by the spreading brush roller 25 is scattered. An auxiliary roller 27 that is disposed at a position in contact with the roller 25 and rotates in the opposite direction to the spray brush roller 25 is provided.

  According to the said structure, the release powder F is scattered in the range below the spreading | diffusion brush roller 25, and the dispersion | distribution of the release powder F to the range which is not intended other than that is suppressed. As a result, unevenness in the amount of the release powder F adhering to the surface of the glass plate G is less likely to occur, and the occurrence of defects such as pits due to the unevenness in the amount of adhesion of the release powder F can be suppressed. Moreover, according to the said structure, since it can continuously perform adhesion process S1 with respect to the several glass plate G supplied by the conveying apparatus 10, That is, since it is a continuous type release powder spraying apparatus, it is a batch type. Compared with the mold release powder spraying apparatus, the attaching step S1 can be performed easily and efficiently.

  (6) In the adhesion step S1, the rotation speed of the spray brush roller 25 in the release powder spray device 20 is set to 40 to 400 rpm, and the wire diameter of the linear part constituting the brush portion 25a of the spray brush roller 25 is set to 0.01. It is set to ~ 0.2mm.

  According to the above configuration, the release powder F can be finely dispersed and dispersed. As a result, unevenness in the amount of the release powder F adhering to the surface of the glass plate G is less likely to occur, and the occurrence of defects such as pits due to the unevenness in the amount of adhesion of the release powder F can be suppressed.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described.
The manufacturing method of the glass article of 2nd Embodiment differs from 1st Embodiment in the point which has the adjustment process described below, and the other point is the same as that of 1st Embodiment.

(Adjustment process)
The adjustment step is based on the adhesion rate so that the adhesion rate is within the specific range when the adhesion rate measured in the adhesion rate measurement step S2 is determined to be outside the specific range in the determination step S3. This is a step of adjusting parameters related to the state of application of the release powder F in the attaching step S1.

  Examples of the parameters include the conveyance speed of the conveyance device 10, the rotation speed of the supply roller 22, the rotation speed of the spray brush roller 25, and the rotation speed of the auxiliary roller 27. For example, the deposition rate tends to increase by setting the transport speed of the transport apparatus 10 to be slow. Moreover, there exists a tendency for an adhesion rate to increase by setting the rotational speed of the spreading | diffusion brush roller 25 fast. Only one of the above parameters may be adjusted, or a plurality may be adjusted simultaneously. It is particularly preferable to adjust the rotational speed of at least one of the supply roller 22 and the spray brush roller 25.

Next, operations and effects of the second embodiment will be described.
(7) It has the adjustment process which adjusts the parameter relevant to the dispersion | distribution state of the mold release powder in adhesion process S1 based on the adhesion rate measured in adhesion ratio measurement process S2.

  According to the said structure, it can suppress that the glass plate G which does not have the adhesion rate of the mold release powder F in a specific range in adhesion process S1. And the glass plate G in which the adhesion rate of mold release powder F exists in a specific range, ie, the glass plate G which cannot produce defects, such as a pit, can be produced efficiently. As a result, the production efficiency of the glass article can be increased. The adjustment process is particularly effective when setting the conditions for the adhesion process S1 when the production line is started up.

(8) The parameter related to the spraying state of the release powder F is the rotational speed of at least one of the supply roller 22 and the spray brush roller 25 in the release powder spraying device 20.
According to the said structure, the adhesion rate of the mold release powder F can be adjusted easily.

In addition, this embodiment can also be changed and embodied as follows.
-About 2nd Embodiment, it is good also as a structure which feedback-controls the mold release powder spraying apparatus 20 so that the adhesion rate measured in adhesion rate measurement process S2 may be in a specific range. For example, as shown in the broken line part of FIG. 3, it comprises so that the adhesion rate measured in adhesion rate measurement process S2 may be input into the control part 29 of the mold release powder spraying apparatus 20. FIG. And in the control part 29, the rotational speed of each roller which makes the difference of the input adhesion rate and a specific range or a specific value (for example, the median value of a specific range) near zero is calculated, and each roller is calculated with the said rotational speed. The drive of each drive unit is controlled so as to rotate.

  -About 2nd Embodiment, you may perform an adjustment process also when the adhesion rate measured in adhesion rate measurement process S2 exists in a specific range. For example, when the adhesion rate is a value close to the lower limit (for example, a range of 10% on the lower limit side) or a value close to the upper limit (for example, a range of 10% on the upper limit side), the adhesion rate is within the specific range. It is good also as a structure which adjusts the parameter relevant to the application | coating state of the mold release powder F in adhesion process S1 so that it may approximate to a median value.

  -About 1st Embodiment and 2nd Embodiment, the adhesion process S1 is performed with respect to the glass for a test | inspection with the predetermined | prescribed timing at the time of start-up of a manufacturing line, etc., and a predetermined | prescribed period, and the inspection which the mold release powder F adhered You may perform adhesion rate measurement process S2 and determination process S3 with respect to the glass for glass. In this case, the effect similar to said (4) is acquired by using the glass plate of the color tone different from the color tone of the mold release powder F as test | inspection glass.

  -About 1st Embodiment and 2nd Embodiment, you may perform adhesion rate measurement process S2 and determination process S3 for all the glass plates G which passed adhesion process S1. In this case, it can suppress more reliably that the glass plate G to which the mold release powder F does not adhere suitably is provided to heating process S4. Therefore, generation | occurrence | production of defects, such as a pit resulting from the adhesion state of the mold release powder F, can be suppressed more suitably.

  -About 1st Embodiment and 2nd Embodiment, when it determines with the adhesion rate of the glass plate G which performed adhesion rate measurement process S2 and determination process S3 being outside a specific range, based on the adhesion rate, The adhesion rate of the glass plate G may be adjusted. For example, when it determines with an adhesion rate being smaller than a specific range, the process of adhesion process S1 is implemented again to the said glass plate G. FIG. In addition, when it is determined that the adhesion rate is larger than the specific range, a process of removing at least a part of the release powder F from the glass plate G is performed.

  When treated in this way, the release powder F was once removed for all the glass plates G for which the adhesion rate was determined to be outside the specific range, and the process of the adhesion step S1 was performed again. Compared with the case, the glass plate G in which the adhesion rate of the release powder F is within a specific range can be efficiently produced. Such a process is particularly effective when the adhesion rate measurement step S2 and the determination step S3 are performed on all the glass plates G that have undergone the adhesion step S1.

  -About 1st Embodiment and 2nd Embodiment, the structure for spraying the mold release powder F is not specifically limited. For example, with respect to the release powder spraying device 20, the arrangement position and rotation direction of each roller may be changed, and the auxiliary roller 27 may be omitted. Further, the release powder spraying device may be a batch type.

The above embodiment will be described more specifically with reference to test examples. The present invention is not limited to these.
As Test Examples 1 to 3, three glass plates (length 1200 mm × width 2100 mm × thickness 4 mm) made of crystalline glass are prepared, and the release powder is attached to one side of each glass plate so that the attachment state is different. I let you. And the surface of each test example was image | photographed with the CCD camera, and the adhesion rate of the mold release powder in each test example was measured from the obtained image. The results are shown in Table 1.

Next, the glass plate of each test example is placed on the setter for heat treatment with the surface to which the release powder is attached facing downward, and heat treatment is performed at 800 ° C. for 1 hour and 900 ° C. for 20 minutes. went. Thereafter, the surface of the glass plate of each test example was observed to determine the number of pits generated per 36 mm ² . The results are shown in Table 1.

As shown in Table 1, the number of pits generated in the glass article is greatly reduced by setting the release powder adhesion rate to 20% or more. From this result, at the time of manufacturing a glass article, it is possible to subject the glass plate, which is considered to have the release powder suitably attached based on the adhesion rate, to the heating step, pits resulting from the release state of the release powder, etc. It can be seen that this is effective in suppressing the occurrence of defects.

F ... Mold release powder, G ... Glass plate, S1 ... Adhesion process, S2 ... Adhesion rate measurement process, S3 ... Determination process, S4 ... Heating process, 10 ... Conveying device, 20 ... Mold release powder spraying device, 21 ... Container 22 ... Supply roller, 22a ... Recess, 24 ... First drive unit, 25 ... Spray brush roller, 25a ... Brush part, 26 ... Second drive unit, 27 ... Auxiliary roller, 28 ... Third drive unit, 29 ... Control Department.

Claims (9)

A method for producing a glass article, comprising: an adhesion step of attaching a release powder to the surface of a crystalline glass plate; and a heating step of heating and crystallizing the glass plate in a stacked state,
After the adhesion step, an adhesion rate measurement step of calculating the adhesion rate of the release powder by analyzing the image of the surface of the glass plate;
A determination step of determining whether the adhesion rate is within a specific range,
When it determines with the said adhesion rate of the said glass plate being in a specific range, the said glass plate is used for the said heating process, The manufacturing method of the glass article characterized by the above-mentioned. Calculate the area of the adhesion area of the release powder occupying the surface of the glass plate as the adhesion rate,
It is determined whether the said adhesion rate is in the range of 20 to 90%, The manufacturing method of the glass article of Claim 1 characterized by the above-mentioned.   The method according to claim 1, further comprising an adjustment step of adjusting a parameter related to a dispersion state of the release powder in the adhesion step based on the adhesion rate measured in the adhesion rate measurement step. The manufacturing method of the glass article of description. The adhesion step is a step of spraying the release powder from above the glass plate using a release powder spraying device for the glass plate continuously conveyed in a flat state.
The release powder spraying device is:
A supply roller that rotates with the release powder adhered to the surface;
A spray brush roller disposed at a position in contact with the supply roller, rotating in a direction opposite to the supply roller, and scraping and releasing the release powder adhering to the surface of the supply roller;
The method for producing a glass article according to claim 3, wherein the parameter is a rotational speed of at least one of the supply roller and the spray brush roller.   When the adhesion rate measurement step and the determination step are selectively performed on the specific glass plate that has undergone the adhesion step, and it is determined that the adhesion rate is within the specific range, release in the adhesion step The glass plate that has undergone the adhesion step within a predetermined period in which a powder dispersion state is the same as that of the glass plate is considered to have the adhesion rate within the specific range and is subjected to the heating step. Item 5. A method for producing a glass article according to any one of Items 1 to 4.   The method for producing a glass article according to claim 5, wherein the adhesion step, the adhesion rate measurement step, and the determination step are performed on an inspection glass having a color tone different from the color tone of the release powder.   The said adhesion rate measurement process WHEREIN: The image of the surface of the said glass plate in the state which has arrange | positioned the coloring member of the color tone different from the color tone of a mold release powder on the back side is analyzed. The manufacturing method of the glass article as described in claim | item. When the adhesion rate of the release powder on the glass plate is determined to be smaller than the specific range, the glass plate is again subjected to the process of the adhesion step,
8. The method according to claim 1, wherein when it is determined that the adhesion rate of the release powder on the glass plate is larger than the specific range, at least a part of the release powder on the glass plate is removed. A method for producing a glass article according to claim 1. A release powder spraying device for spraying the release powder to adhere the release powder to the surface of the glass plate,
A supply roller that rotates with the release powder adhered to the surface;
A spray brush roller that is disposed at a position in contact with the supply roller, rotates in a direction opposite to the supply roller, scrapes and releases the release powder attached to the surface of the supply roller, and
Mold release comprising an auxiliary roller that is disposed at a position in contact with the supply roller on the side where the release powder scraped by the spray brush roller is scattered and rotates in the opposite direction to the spray brush roller. Powder spreader.