JP2008016623A - Continuous furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous furnace capable of isolating a defective member to be heated from a nondefective member to be heated, without deteriorating its state. <P>SOLUTION: A continuous furnace 50 comprises a photographic unit 12, a control unit 30 and a route switching unit 14. The photographic unit 12 is arranged so that the image is made in a glass plate thermally treated by a thermal treatment unit 10. The control unit 30 determines the quality of the glass plate of a test object, by comparing a previously stored reference image of a normal glass plate with the image of the glass plate of the test object, which is photographed by the photographic unit. The route switching unit 14 transports a defective glass plate 20 to a first route extended, so that a transport pass in the furnace is extended and transports a nondefective glass plate 20 to another second route which is different from the first route, based on the result of the determination by the control unit 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a continuous furnace that performs heat treatment on a member to be heated such as a glass plate.

  A member to be heated that is easily damaged during heat treatment, such as a glass plate, may be cracked while being conveyed in a continuous furnace. When a crack occurs in the member to be heated, such a member to be heated is a defective product, so it is not necessary to transport it to the subsequent process. In addition, the heated member that has cracked should be removed from the conveyance path because it may interfere with the conveyance of other normal heated members.

Therefore, in the prior art, there is disclosed a glass substrate transfer device that detects cracks in a heated member (glass plate) using a plurality of transmission optical sensors (see, for example, Patent Document 1). .
JP 2003-218187 A

  However, in the glass plate transfer apparatus described in Patent Document 1, it is possible to detect cracks in the heated member, but it is not possible to detect minute cracks, defects, or heating unevenness of the heated member. A member to be heated having cracks, defects or uneven heating is also a defective product and should not be transported to subsequent processes. In addition, depending on the manner of subsequent conveyance, the defective product may be further deteriorated and cause a conveyance trouble. For example, it is conceivable that a defective product is divided during the subsequent conveyance to become a fragment and gets stuck in the conveyance path by clogging between the conveyance rollers. For this reason, it is important to detect not only cracks of the heated member but also cracks, defects and heating unevenness of the heated member, and remove them from the non-defective conveyance path without deteriorating the state.

  An object of the present invention is to provide a continuous furnace capable of separating a defective heated member from a non-defective heated member without deteriorating its state.

  The continuous furnace which concerns on this invention is equipped with the heat processing part which heat-processes with respect to the to-be-heated member conveyed on the conveyance path | route in a furnace. A typical example of the member to be heated includes a glass plate used in a flat panel display such as a plasma display or a liquid crystal display, but is not limited thereto.

  The continuous furnace includes an imaging unit, a determination unit, and a path switching unit. The imaging unit is arranged to capture an image of the heated member that has been heat-treated by the heat-treating unit. Examples of the arrangement position of the imaging unit include the vicinity of the outlet of the heat treatment unit and the upper part of the lifter that guides the heated member to the next process, for example, the cooling process.

  The determination unit compares the reference image data representing the normal image of the heated member stored in advance with the inspection image data representing the image of the heated member captured by the imaging unit, thereby obtaining the object to be inspected. The quality of the heating member is determined. When acquiring image data, it is preferable to image the upper surface of the heated member. By performing the quality determination of the heated member by analyzing the image data, various defects that can occur in the heated member are detected. Examples of defects include cracks, cracks, discoloration due to heating unevenness, and defects.

  The path switching unit transports the heated member determined to be defective by the determination unit to a first path arranged to extend the in-furnace transport path. The reason why the first path is arranged on the extension line of the in-furnace transport path is to guide defective products to the first path by the same transport method as before. Further, the path switching unit conveys the heated member determined to be non-defective by the determination unit to a second path arranged separately from the first path. The second path is a path for guiding the member to be heated to the subsequent process.

  In the continuous furnace of the present invention, when all the heated members that have passed through the heat treatment section are judged as good or bad by the judgment section and a defective product is found, the defective product is transported to the first path. Since the first path is arranged on the extension line of the in-furnace transport path, the defective product is sent out from the in-furnace transport path to the first path in the transport state as it is. As a result, when a defective product is transported from the in-furnace transport route to the first route, it is difficult for an external force to act on the defective product, and the state of the defective product is prevented from deteriorating.

  According to the present invention, a defective heated member can be separated from a non-defective heated member without deteriorating its state.

  Hereinafter, a roller hearth type continuous firing furnace (hereinafter referred to as a firing furnace) 50 which is a first embodiment of the firing furnace of the present invention will be described. The firing furnace 50 is used for heat treatment of the glass plate 20 used in a flat panel display (FPD). In the following embodiments, the firing furnace 50 performs a firing process on the glass plate 20 to which a paste or the like is applied.

  As shown in FIG. 1, the firing furnace 50 includes a plurality of transport rollers 16, a heat treatment unit 10, an imaging unit 12, and a path switching unit 14. The conveyance rollers 16 are arranged in a horizontal direction at a predetermined pitch and constitute an in-furnace conveyance path for conveying the glass plate 20. The heat treatment unit 10 performs a baking process on the glass plate 20. The imaging unit 12 acquires an image of the upper surface of the glass plate 20 that has passed through the heat treatment unit 10. In the present embodiment, the imaging unit 12 includes a CCD camera and an AD conversion unit. The AD conversion unit converts the image acquired by the CCD camera into digital data, and supplies the digital data to the control unit 30 as inspection image data. However, the configuration of the imaging unit 12 is not limited to this, and a CMOS camera may be employed instead of the CCD camera.

  As illustrated in FIG. 2, the path switching unit 14 conveys the glass plate 20 to either the first path 142 or the second path 143. Specifically, the path switching unit 14 transports the defective glass plate 20 to a first path provided on an extension line of the in-furnace transport path. On the other hand, the path switching unit 14 guides only the non-defective products among the heat-treated glass plates 20 to the second path 143 disposed in the direction orthogonal to the transport direction. The second path 143 is a path that continues to the subsequent process.

  FIG. 3 is a block diagram showing a schematic configuration of the continuous firing furnace. As shown in FIG. 3, the firing furnace 50 includes a control unit 30. The control unit 30 is connected to each of the heat treatment unit 10, the imaging unit 12, and the path switching unit 14, and controls operations of these units. The control unit 30 is connected to the transport unit 22. The transport unit 22 drives the transport roller 16 based on an instruction from the control unit 30. Further, the control unit 30 includes an image storage unit 301. The image storage unit 301 stores reference image data used when determining the quality of the glass plate 20 described later. Further, the image storage unit 301 may be used for temporarily storing inspection image data.

  Next, a schematic configuration of the route switching unit 14 will be described with reference to FIGS. 4 (A) and 4 (B). The path switching unit 14 includes a plurality of shafts 28 that support the conveyance rollers 26 and the conveyance rollers 28. Each shaft 28 is supported by the shaft elevating mechanism 24 so as to be movable up and down. The shaft elevating mechanism 24 performs elevating control of each shaft 28 and rotational drive control of each conveying roller 28 based on a signal from the control unit 30. Specifically, the shaft elevating mechanism 24 raises each shaft 28 only when the non-defective glass plate 20 has been conveyed. As a result, as shown in FIG. 4B, the non-defective glass plate 20 is slightly lifted by the transport roller 26. By rotating the transport roller 26 in this state, the non-defective glass plate 20 is moved from the in-furnace transport path constituted by the transport rollers 16 to the transport roller 161 for transporting the glass plate 20 to the subsequent process. The shaft elevating mechanism 24 stops each conveying roller 26 and lowers each shaft 28 when the glass plate 20 reaches the conveying roller 161. As a result, the non-defective glass plate 20 is properly placed on the conveyance roller 161, and the conveyance roller 161 can guide the glass plate 20 to the subsequent process.

  On the other hand, the defective glass plate 20 conveyed to the first path 142 may be pulled out of the apparatus as it is, recovered in a recovery container, or dropped downward from the end of the first path.

  The conveyance of the defective product conveyed to the first path 142 will be described with reference to FIG. The first path 142 is provided with a swing frame 149 to which a plurality of transport rollers are attached. The swing frame 149 includes a shaft 146 that is pivotally supported by the furnace body, and is configured to swing as the shaft 146 rotates. The path switching unit 14 includes a motor 148 connected to the shaft 146 and capable of rotating in both forward and reverse directions. The motor 148 is configured to rotate in the forward direction or the reverse direction based on the pulse signal supplied from the control unit 30. As the motor 148 rotates, the swing frame 149 moves between a first position indicated by a solid line and a second position indicated by a broken line in FIG. If the swing frame 149 is arranged at the first position, the defective glass plate 20 can be pulled out of the apparatus. On the other hand, if the swing frame 149 is arranged at the second position, the defective glass plate 20 can be collected in the plate collection container 18.

  Thus, according to the continuous furnace 50 which concerns on 1st Embodiment, it becomes possible to isolate | separate and collect the defective glass plate 20 from a good product, without deteriorating the state. In addition, since a large-scale apparatus is not required for collecting defective glass plates 20, the configuration of the continuous furnace 50 is not complicated.

  FIG. 6 is a flowchart illustrating an example of an operation procedure of the control unit 30 during the baking process of the glass plate 20. When performing a baking process with respect to the glass plate 20, the control part 30 is set to the predetermined | prescribed temperature profile, and lets the inside of the furnace body which comprises the heat processing part 10 pass (S1). Subsequently, the control unit 30 causes the imaging unit 12 to read the upper surface of the glass plate 20 that has passed through the heat treatment unit 10, and acquires inspection image data (S2). Subsequently, the control unit 30 reads reference image data from the image storage unit 301 (S3). Here, the reference image data refers to image data representing an image of the upper surface of a normal glass plate 20 that has been well heat-treated. In this embodiment, the reference image data is acquired by reading the upper surface of a normal glass plate 20 in advance by the imaging unit 12 and storing the image data in the image storage unit 301.

  Subsequently, the control unit 30 determines whether or not the glass plate 20 is a non-defective product based on the inspection image data related to the glass plate 20 to be inspected (S4). Specifically, the control unit 30 determines whether the features such as the shape, color, and pattern of the image on the upper surface of the glass plate 20 represented by the reference image data and the inspection image data match. In order to accurately determine whether or not the features represented by the reference image data and the inspection image data match, it is possible to perform noise removal processing on the reference image data and also perform noise removal processing on the inspection image data. preferable.

  FIG. 7A shows an image of the upper surface of a normal glass plate 20 represented by the reference image data. When the image on the upper surface of the glass plate 20 represented by the inspection image data matches the image shown in FIG. 7A, the control unit 30 determines that the glass plate 20 to be inspected is a non-defective product.

  FIG. 7B to FIG. 7E show examples of images of defective glass plates 20. FIG. 7B shows a state in which a crack 203 is generated in the glass plate 20. FIG. 7C shows a state in which fine cracks 204 have entered the glass plate 20. FIG. 7D shows a state where the heating unevenness 205 is generated on the glass plate 20. FIG. 7E shows a state in which a defect 206 is generated at the corner of the glass plate 20. The control unit 30 determines that the product is defective when any of the features shown in FIGS. 7B to 7E appears in the image represented by the inspection image data.

  In the determination step of S4, when it is determined that the glass plate 20 to be inspected is a non-defective product, the control unit 30 controls the path switching unit 14 to move the glass plate 20 through the second path 143. It conveys to a subsequent process (S5).

  On the other hand, in the determination step of S4, when it is determined that the glass plate 20 to be inspected is a defective product, the control unit 30 controls the path switching unit 14 to move the glass plate 20 to the first path 142. (S6). Since the first path 142 is arranged to extend the in-furnace transport path, the defective glass plate 20 can be transported to the first path 142 by the same transport method as before. As a result, when the defective glass plate 20 is transported from the in-furnace transport path to the first path 142, the state is unlikely to deteriorate.

  Next, a schematic configuration of the firing furnace 502 in the second embodiment will be described with reference to FIG. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. The firing furnace 502 includes a heat treatment unit 101 instead of the heat treatment unit 10. The heat treatment unit 101 is configured by arranging a furnace body 102 for performing a firing process and a slow cooling process and a furnace body 103 for performing a cooling process in two upper and lower stages. A lifter 32 that guides the glass plate 20 to the furnace body 103 is disposed in the vicinity of the outlet of the furnace body 102.

  In the second embodiment, an imaging unit 121 disposed above the lifter 32 is provided instead of the imaging unit 12. In this embodiment, the non-defective glass plate 20 is conveyed to the furnace body 103 by the lifter 32. On the other hand, the defective glass plate 20 passes through the lifter 32 and is transported to the vicinity of the take-out port 34, and the defective glass plate 20 is taken out of the firing furnace 502 through the take-out port 34. Is possible. In this embodiment, a configuration in which the glass plate 20 is forcibly dropped downward instead of the takeout port 34 may be employed.

  The above description of the embodiment is to be considered in all respects as illustrative and not restrictive. The scope of the present invention is shown not by the above embodiments but by the claims. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

It is a figure which shows schematic structure of a continuous baking furnace. It is a figure which shows operation | movement of the path | route switching part in 1st Embodiment. It is a block diagram which shows schematic structure of a continuous baking furnace. It is a figure which shows schematic structure of the path | route switching part in 1st Embodiment. It is a figure explaining conveyance of the glass plate in a 1st path | route. It is a flowchart which shows the operation | movement procedure of the control part at the time of a baking process. It is a figure which shows the example of the image of the upper surface of a glass plate. It is a figure which shows schematic structure of the path | route switching part in 2nd Embodiment.

Explanation of symbols

10-heat treatment part 12-imaging part 14-path switching part 20-glass plate 30-control part 50-continuous furnace

Claims (3)

It is a continuous furnace provided with a heat treatment part for performing heat treatment on a heated member conveyed on the in-furnace conveyance path,
An imaging unit arranged to image the heated member heat-treated by the heat treatment unit;
The quality of the heated member is determined by comparing the reference image data representing the normal heated member image stored in advance with the inspection image data representing the heated member image captured by the imaging unit. A determination unit to perform,
The heated member determined to be defective by the determination unit is transported to a first path arranged to extend the in-furnace transfer path, and the heated member determined to be non-defective by the determination unit A path switching unit that is disposed separately from the first path and transports the heated member to a second path for the subsequent process;
A continuous furnace characterized by comprising:   The continuous furnace according to claim 1, wherein the second path is disposed to be orthogonal to the in-furnace transport path.   The continuous furnace according to claim 1, further comprising a recovery unit that recovers the member to be heated conveyed to the first path.

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