Blow molding apparatus and blow molding method

Abstract

The blow molding apparatus of the present application is provided with: an injection molding section that injection-molds a pre-molded blank of a bottomed cylindrical shape; a heating section that heats the pre-molded blank having retained heat at the time of injection molding; a blow molding section that blow-molds the pre-molded blank after heating; a first conveying section that holds the pre-molded blank after injection molding and conveys it via the heating section; and a second conveying section that holds the conveyed pre-molded blank in an upright state and conveys it to the blow molding section, the blow molding apparatus further being provided with: an inspection section that photographs the pre-molded blank being conveyed and detects defects in the appearance of the pre-molded blank based on the obtained image; and an ejection section that ejects the pre-molded blank in which a defect has been detected to the outside.

Description

Technical Field

[0001] This invention relates to blow molding apparatus and blow molding method, and more particularly to blow molding apparatus and blow molding method capable of performing appearance inspection of preforms within the molding apparatus. Background Technology

[0002] Typically, a known method for manufacturing resin containers, such as PET bottles, involves injection molding a resin material to form a cylindrical preform, followed by blow molding to extend the preform into the shape of a container. However, in the injection-molded preform, defects such as damage, shrinkage marks, black spots, bubbles, and foreign matter inclusions can sometimes occur. If the preform has these defects, the container manufactured by blow molding will also be defective and cannot be commercialized. Therefore, it is preferable to inspect the preform before blow molding to remove any defective preforms from the production line.

[0003] Previously, as such preform inspection devices, structures were proposed that use sensors to determine the quality of the diameter of the neck, the upper end face of the neck, and the height of the neck (for example, see Patent Document 1), and structures that use two cameras to detect appearance defects on the entire circumference of the sidewall of the preform (for example, see Patent Document 2).

[0004] Prior art literature Patent documents Patent Document 1: Japanese Patent Publication No. 6-6331 Patent Document 2: Japanese Patent Application Publication No. 11-30593 Patent Document 3: Japanese Patent No. 5563095 Summary of the Invention

[0005] The problem that the invention aims to solve In blow molding equipment for manufacturing resin containers, there are two approaches: a one-stage approach (or hot preform approach) that reduces energy loss by performing injection molding and blow molding of preforms in a single molding machine, and a two-stage approach (or cold preform approach) that improves production efficiency by setting up separate injection molding and blow molding units for preforms.

[0006] Furthermore, the applicant has commercialized an injection stretch blow molding apparatus, known as a 1.5-stage method, which combines the advantages of both 1-stage and 2-stage methods (see, for example, Patent Document 3). In this 1.5-stage method, energy loss is reduced by utilizing the heat retained during injection molding for blow molding, and production efficiency is improved by differentiating the number of preforms processed in the injection molding cycle of the injection molding section within a single molding machine from the number processed in the blow molding cycle of the blow molding section.

[0007] In the above-described methods, the two-stage method allows for easy inspection of the preform before it is fed into the blow molding machine. On the other hand, in the 1.5-stage method, since the injection molding to blow molding processes are performed continuously within a single molding machine, it is difficult to apply the aforementioned conventional preform inspection device.

[0008] The present invention was made in view of the following problem, and its object is to provide a blow molding apparatus capable of performing visual inspection of preforms in a 1.5-stage blow molding apparatus and efficiently discharging preforms with defects to the outside.

[0009] Technical solutions for solving the problem One aspect of the present invention is a blow molding apparatus, characterized in that the blow molding apparatus comprises: an injection molding section for injection molding a bottomed cylindrical preform made of resin; a heating section for heating the preform, which retains heat during injection molding, to a temperature suitable for blow molding; a blow molding section for blow molding the heated preform to manufacture a resin container; a first conveying section for holding the injection-molded preform and conveying it via the heating section; and a second conveying section for holding the conveyed preform in an upright position and conveying it to the blow molding section. The blow molding apparatus further comprises: an inspection section for photographing the conveyed preform and detecting defects in the appearance of the preform based on the obtained image; and a discharge section for discharging the preform with defects detected by the inspection section to the outside.

[0010] Invention Effects According to one aspect of the present invention, a blow molding apparatus can be provided, in which a 1.5-stage blow molding apparatus is capable of performing visual inspection of preforms and efficiently discharging preforms with defects to the outside. Attached Figure Description

[0011] Figure 1 It is a top view schematically representing the structure of a blow molding apparatus.

[0012] Figure 2 This is a schematic diagram showing the transport of the preform in the injection molding section and the cooling section.

[0013] Figure 3 This is a diagram showing an example of a pre-plasticized preform.

[0014] Figure 4 This is a top view schematically showing the structure of the first inspection section of the main body of the preform.

[0015] Figure 5 This is a side view schematically showing the structure of the first inspection section for inspecting the bottom of the preform.

[0016] Figure 6 This is a side view schematically showing the structure of the second inspection section for inspecting the top surface of the neck of the preform. Detailed Implementation

[0017] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0018] In the embodiments, to facilitate understanding, structures and elements other than the main parts of the invention are simplified or omitted in the description. Furthermore, in the drawings, the same symbols are used to denote the same elements. Additionally, the shapes, dimensions, etc., of the elements shown in the drawings are schematic and do not represent actual shapes, dimensions, etc.

[0019] <Description of Blow Molding Equipment> First, refer to Figure 1 A blow molding apparatus 100 according to one embodiment of the present invention will be described. Figure 1 This is a schematic top view illustrating the structure of a blow molding apparatus. Additionally, Figure 2 This is a schematic diagram showing the transport of the preform in the injection molding section and the cooling section.

[0020] The blow molding apparatus 100 of this embodiment performs a blow molding method known as the 1.5-stage method, which combines the advantages of both a one-stage (hot preform) and a two-stage (cold preform) method. In the 1.5-stage blow molding method, containers are manufactured by blow molding a preform that is still hot from the injection molding process, essentially the same as in the one-stage method. However, the blow molding cycle in the 1.5-stage method is set to be shorter than the injection molding cycle of the preform. Furthermore, multiple preforms formed in one injection molding cycle are blow molded in multiple blow molding cycles.

[0021] Although there are no specific limitations, the ratio (N:M) of the number of preforms injected at the same time to the number of containers blow-molded at the same time is set to, for example, 3:1.

[0022] like Figure 1 As shown, the blow molding apparatus 100 includes an injection molding section 110, a cooling section 120, a heating section 130, and a blow molding section 140.

[0023] In addition, the blow molding apparatus 100 includes a continuous conveying section (first conveying section) 150, which conveys the preform 200 transported from the cooling section 120 to the blow molding section 140 via the heating section 130.

[0024] The continuous conveying unit 150 is a conveying device that continuously conveys the conveying jigs 152, which hold the pre-plasticized blank 200 in an inverted state, along a circular conveying line 151 having multiple bends. That is, the continuous conveying unit 150 can repeatedly convey each conveying jig 152 along the circular conveying line 151.

[0025] In addition, the blow molding apparatus 100 is equipped with a control device 400 for unified control of the operation of the blow molding apparatus 100. The control device 400 is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM and I / O interface (not shown), and realizes various control functions by reading and executing programs stored in RAM or ROM.

[0026] In addition, the blow molding apparatus 100 includes: a display device 500 that displays the status of the blow molding apparatus 100 to the operator or others according to the command of the control device 400; and a storage device 600 that stores data related to the status of the blow molding apparatus 100.

[0027] The injection molding section 110 injection molds a bottomed cylindrical preform 200 as a resin molded product.

[0028] like Figure 2 As shown, the injection molding unit 110 includes: a neck mold (not shown) and a core mold 111 disposed on the upper side; a cavity mold 112 disposed on the lower side; and a mold closing mechanism 114 that closes the neck mold, core mold 111, and cavity mold 112 by means of a connecting rod 113. The injection molding unit 110 injection molds a preform 200 by filling resin material (raw material) into the injection space formed by the core mold 111 and the cavity mold 112 from an injection device (not shown).

[0029] Here, refer to Figure 3 An example of the preform 200 used in this embodiment will be described. Figure 3 (A) is a top view of the neck (opening) of the preform 200 in an upright position, showing the top surface (upper end face). Figure 3 (B) is the front view of the preform 200. Figure 3 (C) is a bottom view showing the hemispherical bottom of the preform 200.

[0030] The preform 200 has an overall cylindrical shape with one open end and the other closed end. The preform 200 includes a cylindrical main body 201, a bottom 202 that closes the other end of the main body 201, and a neck 203 with an opening at one end of the main body 201. The neck 203 has a circular top surface 204.

[0031] The raw material for the preform 200 is a thermoplastic synthetic resin, which can be appropriately selected according to the intended use of the container. Specific types of materials include, for example: PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexanediol terephthalate), Tritan (Tritan (registered trademark): a copolyester manufactured by Eastman Chemical Company), PP (polypropylene), PE (polyethylene), PC (polycarbonate), PES (polyethersulfone), PPSU (polyphenylsulfone), PS (polystyrene), COP / COC (cyclic olefin polymer), PMMA (polymethyl methacrylate: acrylic acid), PLA (polylactic acid), etc.

[0032] In this embodiment, the injection molding section 110 is, for example, composed of 3 columns × N' units (N' being multiple units). Figure 1 In one example, there are 4 preforms 200. N can also be multiple, and in the case of N'=4, N=12 preforms 200 are formed simultaneously. In addition, the preforms 200 are formed in the injection molding section 110 in an upright state with the neck 203 facing upward, and the preforms 200 are transported in the injection molding section 110 in an upright state.

[0033] like Figure 2 As shown, the injection molding unit 110 includes a receiving part 115 for removing the injection-molded preform 200 outside the injection molding unit 110. The receiving part 115 is configured to be able to move in the horizontal direction (X direction in the figure) from a receiving position below the core mold 111 to an outermost junction position beyond the space enclosed by the connecting rod 113.

[0034] The receiving section 115 holds 12 cans 300 that respectively accommodate 3 rows × 4 quantities of pre-plasticized preforms 200 formed by the injection molding section 110. Each can 300 is an example of a pre-plasticized preform holding member and has a receiving space corresponding to the shape of the pre-plasticized preform 200.

[0035] In addition, the receiving unit 115 is equipped with a mechanism (not shown) for adjusting the spacing of the columns of the cans 300 (the spacing in the X direction in the figure) during movement from the receiving position to the handover position. As a result, the receiving unit 115 changes the spacing of the columns of the pre-plasticized blanks 200 from a wide spacing state at the receiving position to a narrow spacing state at the handover position.

[0036] A preform 200, injection-molded by injection molding unit 110, is supplied from injection molding unit 110 to cooling unit 120. Cooling unit 120 forcibly cools the preform 200 formed by injection molding unit 110. The preform 200, cooled to a given temperature, is transported out from cooling unit 120 and continuously conveyed along conveyor line 151.

[0037] Furthermore, the cooling of the preforms 200 in the cooling section 120 is performed to eliminate temperature deviations among the preforms 200 after injection molding and to convey them to the heating section 130 in a uniform state. That is, the preforms 200 do not need to be cooled to room temperature and are conveyed to the heating section 130 while still hot from injection molding. Therefore, in this embodiment, the same good energy efficiency as the one-stage method can be obtained.

[0038] like Figure 2 As shown, a conveying device 180 is provided between the injection molding section 110 and the cooling section 120. The conveying device 180 conveys the preform 200 from the receiving section 115 to the cooling section 120 in an upright state. The conveying device 180 includes a holding section 181 that holds the neck 203 of the upright preform 200, and is configured to be movable in the vertical direction (Z direction in the figure) and the horizontal direction (X direction in the figure) by means of a cylinder (not shown).

[0039] like Figure 2 As shown, the cooling section 120 has a flipping section 121. The flipping section 121 is configured to be able to flip about an axis 122 extending in the X direction in the figure, and to be able to move up and down in the Z direction (vertical direction) in the figure. In order to accommodate 3 rows × 4 units of pre-plasticized blanks 200, the first surface 121a and the second surface 121b opposite to the first surface 121a shown in the figure are each provided with 12 cooling tanks 310.

[0040] The cooling tanks 310 disposed on the first surface 121a and the second surface 121b of the flipping section 121 are cooled by refrigerant circulating in the refrigerant passage (not shown) provided in the flipping section 121. In addition, the cooling tanks 310 of the flipping section 121 have the function of attracting and holding the pre-plasticized blank 200 contained therein.

[0041] Furthermore, the flipping section 121 flips the upright preform 200 received from the conveying device 180 into an inverted state with the neck 203 facing down during the cooling time. Then, the inverted preform 200 is handed over to a conveying clamp 152, which is located in a standby position below the cooling section 120 and consists of multiple rows of continuous conveying sections 150. The conveying clamp 152 holding the preform 200 is sequentially conveyed along the conveyor line 151 by the driving force of sprockets 154 and the like.

[0042] The heating section 130 heats the inverted preform 200, which is continuously conveyed by the continuous conveying section 150, to a suitable stretching temperature. The heating section 130 has a plurality of heaters (not shown) arranged at given intervals along the conveying line 151 on both sides of the conveying line 151. Within the heating section 130, the inverted preform 200 is heated while rotating around its axis, and the entire preform 200 is heated uniformly.

[0043] In addition, the blow molding apparatus 100 has an intermittent conveying section (second conveying section) 160 and a transfer section 170 on the downstream side of the heating section 130 in the conveying line 151.

[0044] The intermittent conveying section 160 holds and intermittently conveys multiple (M, e.g., 3, 4, etc.) pre-plasticized preforms 200 heated by the heating section 130 in an upright state to the blow molding section 140. The transfer section 170 flips the pre-plasticized preforms 200 that are continuously conveyed in an inverted state along the conveyor line 151 by the continuous conveying section 150, and transfers them to the intermittent conveying section 160 in an upright state.

[0045] Furthermore, in this embodiment, multiple (M') consecutive conveying fixtures 152 in the conveying direction are connected by connecting members (not shown), thereby being unitized (integrated). The aforementioned multiple (M') refers to a number greater than M, such as 8, 9, and 12. When the size of the preform 200 or container is large (e.g., a container with a capacity of 12 liters or more, and its preform), the preform 200 can be arranged in the unitized conveying fixtures 152 in a manner that skips 1 to 3. Moreover, the continuous conveying section 150 repeatedly drives and stops the sprocket 154a on the conveying line 151 downstream of the curved conveying section 155 which bends with a given radius, thereby supplying multiple (M, for example 3, 4, etc.) preforms 200 to the transfer section 170 at one time.

[0046] The transfer section 170 has a flipping device (not shown) at the transfer position P0. The pre-plasticized blank 200, which is conveyed in an inverted state along the conveyor line 151, is flipped into an upright state by the flipping device located on the upper side of the pre-plasticized blank 200 at the transfer position P0. In addition, the transfer section 170 is provided, for example, a lifting device (not shown) for raising and lowering the flipping device. When the upright pre-plasticized blank 200 is raised to a given position (transfer position P1), it is transferred to the intermittent conveying section 160.

[0047] The intermittent conveying section 160 holds the necks 203 of each pre-plasticized preform 200 in an upright state via an openable and closable blow molding conveying chuck member 161. The blow molding conveying chuck member 161 holds the necks 203 of the pre-plasticized preform 200 at a junction position P1 above a junction position P0, causing the pre-plasticized preform 200 to move from the junction position P1 to the blow molding position P2. Thus, multiple pre-plasticized preforms 200 are conveyed to the blow molding section 140 at given intervals.

[0048] The blow molding section 140 includes a pair of parting dies corresponding to the shape of the container, namely the blow molding cavity mold 141, and an air inlet member (not shown) that also serves as a stretching rod. In the blow molding section 140, the intermittent conveying section 160 conveys a given number of pre-plasticized preforms 200 received from the transfer section 170 to the blow molding cavity mold 141, and uses the blow molding cavity mold 141 to stretch and blow mold the pre-plasticized preforms 200, thereby manufacturing the container.

[0049] Furthermore, the container manufactured by the blow molding section 140 is transported by the intermittent conveying section 160 to the container removal position P3 (removal section) outside the blow molding section 140.

[0050] <Instructions for Inspection and Discharge Departments> Next, refer to Figures 4-6 The structural examples of the inspection units (first inspection unit 210, second inspection unit 220) and discharge units (first discharge unit 230, second discharge unit 240) in this embodiment will be described. Furthermore, in this embodiment, the control device 400, display device 500, and storage device 600 of the blow molding apparatus 100 function as part of these inspection units and discharge units.

[0051] As will be described later, the inspection unit in this embodiment takes pictures of the pre-plasticized blank 200 during transport and detects appearance defects at the main body 201, bottom 202 and neck 203 of the pre-plasticized blank 200 based on the obtained images.

[0052] In addition, in this embodiment, the discharge section efficiently discharges the preform 200, whose appearance defects are detected by the inspection section, to the outside of the blow molding apparatus 100.

[0053] Reference Figure 4 and Figure 5 The structure of the first inspection unit 210 in this embodiment will be described. Figure 4 This is a top view schematically showing the structure of the first inspection section 210 for inspecting the main body 201 of the pre-plasticized preform 200. Figure 5 This is a side view schematically showing the structure of the first inspection section 210 for inspecting the bottom 202 of the preform 200.

[0054] In this embodiment, the first inspection section 210 is located downstream of the heating section 130 in the continuous conveying section 150, that is, near the bending conveying section 155.

[0055] The first inspection unit 210 includes at least one, preferably two, cameras 211, 211 for photographing the main body 201 of the pre-plasticized blank 200 being transported in an inverted state, and light sources 212, 212 for these cameras 211, 211. Additionally, the first inspection unit 210 includes a camera 213 for photographing the bottom 202 of the pre-plasticized blank 200 being transported in an inverted state, and a light source 214 for the camera 213.

[0056] Furthermore, the first inspection unit 210 includes a first determination unit 401 that determines whether the preform 200 has any defects in appearance based on information from images captured by cameras 211, 212, and 213. Additionally, the first inspection unit 210 includes a display unit for displaying the determination result and notifying the operator of the determination result; and a storage unit for storing images of the preform 200 with detected defects. In this embodiment, the display device 500 and storage device 600 of the blow molding apparatus 100 function as these display units and storage units, respectively.

[0057] Cameras 211 and 211 are any cameras capable of capturing visible light, and can use known CCD cameras or CMOS cameras.

[0058] like Figure 4 As shown, cameras 211 and 211 capture images of the main body 201 of the pre-plasticized blank 200 when the pre-plasticized blank 200, which is being transported in an inverted state along the conveyor line 151 of the continuous conveyor section 150, reaches a given position (camera position P4). Each of the two cameras 211 and 211 is configured such that its optical axis is at approximately a 90-degree angle to the central axis of the pre-plasticized blank 200 in a plane orthogonal to the central axis of the pre-plasticized blank 200. Therefore, cameras 211 and 211 can capture images of the main body 201 of the pre-plasticized blank 200 approximately around its circumference.

[0059] The light sources 212 and 212 used by the cameras 211 and 211 are arranged on opposite sides of each camera 211 and 211 across the pre-plastic blank 200. By illuminating the pre-plastic blank 200 when taking pictures using the cameras 211 and 211, clear images can be captured.

[0060] The light sources 212 and 212 used for cameras 211 and 211 are not particularly limited as long as they have sufficient light to properly capture images of the preform 200 using cameras 211 and 211. For example, LED lights with a surface shape having the same height and width as the preform 200 can be used.

[0061] Like cameras 211 and 211, camera 213 can be composed of a known camera (CCD camera, CMOS camera) capable of capturing visible light.

[0062] like Figure 4 and Figure 5 As shown, when the pre-plasticized blank 200, which is being conveyed in an inverted state along the conveyor line 151 of the continuous conveyor section 150, reaches the shooting position P4, the camera 213 captures an image of the bottom 202 of the pre-plasticized blank 200. The camera 213 is positioned, for example, directly above the pre-plasticized blank 200 at the shooting position P4, so that it can capture an image of the entire bottom of the pre-plasticized blank 200.

[0063] The light source 214 for the camera 213 is positioned, for example, directly below or below the camera 213, so that the bottom 202 of the preform 200 can be illuminated without blind spots. In this case, a ring-shaped LED light or the like is used as the light source 214 so that the light source 214 does not enter the field of view of the camera 213. The light source 214 can be positioned to illuminate the bottom 202 of the preform 200 located at the shooting position P4 from directly above or above. Alternatively, multiple light sources 214 can be provided.

[0064] The first determination unit 401 is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and I / O interfaces (not shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the first determination unit 401, and performs the function of the first determination unit 401 by reading and executing the program stored in RAM or ROM.

[0065] The first determination unit 401 receives image data of the preform 200 captured by cameras 211, 212, and 213. Based on this image data, it uses a known algorithm to determine whether there are defects in the appearance of the preform 200. In this determination, for example, image processing such as edge detection is performed on the collected image data. For example, if a detected edge exists outside the normal outline of the preform 200, it is determined that a defect exists. Thus, it is determined that the preform 200 has defects such as black spots, bubbles, or foreign matter intrusion in the main body 201 and the bottom 202.

[0066] By displaying the determination result based on the first determination unit 401 on the display device 500, the operator of the blow molding apparatus 100 can obtain the inspection result. The display device 500 is, for example, a liquid crystal display panel, an organic EL display panel, an operation screen, or other display device provided as part of the blow molding apparatus 100. The display device 500 displays a given screen based on the control of the first determination unit 401.

[0067] The judgment result displayed by the display device 500 can be set as a list of information, including image data captured by the first inspection unit 210, presence or absence of defects, identification information of the preform 200, identification information of the transport fixture 152, inspection date and time, location of defects, type of defects, etc.

[0068] In addition, this information is stored in storage device 600. Storage device 600 may be, for example, a storage device such as an HDD or SSD disposed inside the blow molding apparatus 100. Alternatively, storage device 600 may be disposed outside the blow molding apparatus 100.

[0069] The preform 200 with defects detected by the first inspection section 210 is discharged to the outside by the first discharge section 230.

[0070] The first discharge section 230 is provided, for example, on the conveyor line 151 downstream of the intermittent conveyor section 160 and the junction section 170, and has a first discharge mechanism for discharging the pre-plasticized blank 200 held in the conveyor clamp 152 to the outside through the first discharge outlet (not shown).

[0071] Furthermore, the control of the transfer section 170 in the first discharge section 230 for discharging the pre-plasticized preform 200 with defects detected by the first inspection section 210 from the first discharge outlet, and the control of the first discharge mechanism are performed by the first discharge control section 402. The first discharge control section 402 is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and I / O interfaces (not shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the first discharge control section 402, and realizes its function as the first discharge control section 402 by reading and executing the program stored in RAM or ROM.

[0072] The first discharge control unit 402 receives information from the first inspection unit 210 regarding a pre-plasticized preform 200 with a defect detected in the first inspection unit 210. Then, when the pre-plasticized preform 200 with the detected defect reaches the transfer position P0 while flowing on the conveyor line 151, the first discharge control unit 402 controls the transfer unit 170 to bypass the transfer unit 170 and transfer it to the intermittent conveyor 160. Thus, the pre-plasticized preform 200 with the detected defect is not conveyed to the blow molding unit 140 but remains on the conveyor line 151. Afterward, the pre-plasticized preform 200 with the detected defect is conveyed to the first discharge unit 230 together with the conveyor clamp 152, which has returned to the standby position below the cooling unit 120. The pre-plasticized preform 200 arriving at the first discharge unit 230 is discharged to the outside via the first discharge outlet through the first discharge mechanism of the first discharge unit 230.

[0073] Furthermore, in this embodiment, to avoid complicating control and mechanisms, a given number (M') of pre-plasticized blanks 200 held by the connected conveyor clamp 152 are treated as a group, and the removal process is performed on a group basis when a defect is detected. That is, if a defect is detected in any of the group (M') of pre-plasticized blanks 200 held by the connected conveyor clamp 152, the other pre-plasticized blanks 200 included in that group, regardless of whether they have defects, are treated in the same way as the pre-plasticized blank 200 that was found to have a defect. In other words, the aforementioned group of pre-plasticized blanks 200 are not transferred to the intermittent conveyor 160 but are conveyed to the first discharge section 230 and discharged to the outside.

[0074] Next, refer to Figure 6 The structure of the second inspection unit 220 in this embodiment will be described. Figure 6 This is a side view schematically showing the structure of the second inspection section 220, which inspects the top surface 204 of the neck 203 of the preform 200.

[0075] In this embodiment, the second inspection unit 220 is disposed between the junction position P1 and the blow molding position P2 in the intermittent conveying unit 160.

[0076] The second inspection unit 220 is equipped with a camera 215 for capturing images of the top surface 204 of the neck 203 of the pre-plasticized blank 200, which is conveyed in an upright state, and a light source 216 for the camera 215.

[0077] Furthermore, the second inspection unit 220 includes a second determination unit 403 that determines whether the preform 200 has any defects based on information from images captured by the camera 215. Moreover, the second inspection unit 220 includes a display unit for displaying the determination result and notifying the operator of the determination result; and a storage unit for storing images of the preform 200 with detected defects. In this embodiment, the display device 500 and storage device 600 of the blow molding apparatus 100 function as these display units and storage units, respectively.

[0078] Like cameras 211, 212 and 213, camera 215 can be constructed from a known camera capable of capturing visible light.

[0079] like Figure 6 As shown, the camera 215 is positioned above the path through which the pre-plasticized blank 200, held upright by the blow molding conveyor chuck member 161 of the intermittent conveyor 160, moves from the handover position P1 to the blow molding position P2, and captures an image of the top surface 204 of the neck 203 of the pre-plasticized blank 200 passing directly below.

[0080] Furthermore, in this embodiment, the blow molding conveyor chuck member 161 is configured such that each unit holds multiple (M) pre-plasticized blanks 200. Correspondingly, at least one, preferably M, camera 215 is provided on a frame member (not shown) located above the blow molding conveyor chuck member 161. When the number of containers being molded simultaneously is 3 (M=3), each of the 3 (M) cameras 215 corresponds to one of the 3 (M) pre-plasticized blanks 200 held by the blow molding conveyor chuck member 161, thereby enabling the inspection of all 3 (M) pre-plasticized blanks 200 at once, shortening the inspection time required in the second inspection unit 220.

[0081] The light source 216 for camera 215, like the light source 214 for camera 213, is positioned directly below or below camera 215, forming a ring-shaped LED light so that the light source 216 does not enter the field of view of camera 215. The light source 216 can also be positioned to illuminate the top surface 204 of the preform 200 from directly above or above.

[0082] The second determination unit 403, like the first determination unit 401 of the first inspection unit 210, is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and I / O interfaces (not shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the second determination unit 403, and performs its function as the second determination unit 403 by reading and executing a program stored in RAM or ROM.

[0083] The second determination unit 403 receives image data of the preform 200 captured by the camera 215, and uses a known algorithm to determine whether there are defects in the appearance of the preform 200. In this determination, image processing such as edge detection is performed on the collected image data, and a defect is determined to exist if a detected edge exists outside the normal outline of the preform. Thus, a preform 200 with defects such as damage or shrinkage marks on the top surface 204 of the neck 203 is determined.

[0084] By displaying the determination result based on the second determination unit 403 on the display device 500, the operator of the blow molding apparatus 100 can obtain the inspection result. The display device 500 displays a given screen based on the control of the second determination unit 403.

[0085] The judgment result displayed by the display device 500 is similar to the judgment result in the first inspection unit 210. For example, it can be set to a list format that includes image data captured by the second inspection unit 220, whether there are defects, identification information of the preform 200, identification information of the blow molding conveyor chuck component 161, inspection date and time, location of defects, type of defects, etc.

[0086] In addition, this information is stored in storage device 600. As described above, storage device 600 may be, for example, a storage device such as HDD or SSD disposed inside the blow molding apparatus 100, or it may be disposed outside the blow molding apparatus 100.

[0087] The preform 200 with defects detected by the second inspection section 220 is discharged to the outside by the second discharge section 240.

[0088] The second discharge section 240 is provided, for example, at the take-out position P3 or near the outside of the blow molding section 140 in the intermittent conveying section 160, and has a second discharge mechanism for discharging the pre-plasticized preform 200 held by the blow molding conveying chuck member 161 to the outside through the second discharge outlet not shown.

[0089] Furthermore, the control of the blow molding conveying chuck member 161 in the second discharge section 240 for discharging the pre-plasticized preform 200 with defects detected by the second inspection section 220 from the second discharge outlet, and the control of the blow molding section 140 are performed by the second discharge control section 404. The second discharge control section 404, like the first discharge control section 402, is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and I / O interfaces (not shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the second discharge control section 404, and achieves its function as the second discharge control section 404 by reading and executing a program stored in RAM or ROM.

[0090] The second discharge control unit 404 receives information about a pre-plasticized preform 200 with a defect detected in the second inspection unit 220. When the pre-plasticized preform 200 with the detected defect is conveyed to the intermittent conveying unit 160 and reaches the blow molding position P2, the blow molding unit 140 is controlled to prevent blow molding based on the blow molding unit 140. Furthermore, the blow molding unit 140 does not introduce blow molding air into the pre-plasticized preform 200 with the defect detected by the second inspection unit 220, thus suppressing the unnecessary consumption of blow molding air.

[0091] Therefore, the preform 200 with detected defects is not formed into a container but is continuously held by the blow molding conveyor chuck member 161 and conveyed to the second discharge section 240 by the intermittent conveying section 160. The preform 200 that arrives at the second discharge section 240 is discharged to the outside through the second discharge outlet via the second discharge mechanism of the second discharge section 240.

[0092] Furthermore, in this embodiment, to avoid complicating control and mechanisms, a given number (M) of preforms 200 held by the blow molding conveyor chuck member 161 are treated as a group, and the removal process in case of defect detection is performed on a group-by-group basis. That is, if a defect is detected in any of the preforms 200 in the group held by the blow molding conveyor chuck member 161, the other preforms 200 included in that group, regardless of whether they have defects, are treated in the same way as the preforms 200 with the defect detected. In other words, the aforementioned group of preforms 200 are conveyed to the second discharge section 240 without being blow molded and are discharged to the outside.

[0093] The effects of this embodiment will be explained below.

[0094] According to this embodiment, in a blow molding machine 100 that continuously performs injection molding from a preform 200 to blow molding of a container, it is possible to photograph the preform 200 during transport and detect appearance defects at the main body 201, bottom 202, and neck 203 of the preform 200 based on the obtained images. Furthermore, preforms with detected defects can be efficiently discharged to the outside. Therefore, in the 1.5-stage blow molding apparatus, the preform 200 before blow molding can be visually inspected, and defective preforms 200 can be discharged without being blow molded. This allows for early detection of defective products, thus saving on mechanical waste and improving container production efficiency.

[0095] Furthermore, the inspection of the preform 200 is performed by the first inspection section 210 and the second inspection section 220. Therefore, even in a blow molding apparatus with a 1.5-stage process where the preform flips and moves up and down frequently, the appearance inspection can be performed efficiently according to the conveying state of the preform 200. The first inspection section 210 performs an appearance inspection of the main body 201 and bottom 202 of the conveyed preform 200, and the second inspection section 220 performs an appearance inspection of the top surface 204 of the neck 203 of the preform 200 when it is conveyed in an upright state.

[0096] Furthermore, the discharge of the preform 200 with defects detected to the outside is carried out by the first discharge section 230 and the second discharge section 240, thus saving the waste of mechanical operation of the defective preform 200 and efficiently discharging it to the outside. Specifically, the first discharge section 230 discharges the preform 200 with defects detected by the first inspection section 210 during the conveying of the continuous conveying section (first conveying section) 150 to the outside without transferring it to the intermittent conveying section (second conveying section) 160. The second discharge section 240 discharges the preform 200 with defects detected by the second inspection section 220 during the conveying of the intermittent conveying section 160 to the outside without blow molding by the blow molding section 140.

[0097] This invention is not limited to the above-described embodiments. Various improvements and design changes can be made without departing from the spirit of this invention.

[0098] For example, in the above embodiment, a first inspection section for visual inspection of the main body and bottom of the preform and a second inspection section for visual inspection of the top surface of the neck of the preform are respectively provided. However, it may also be configured to provide an inspection section for visual inspection of the main body, bottom and top surface of the neck of the preform at the same time.

[0099] In addition, in the above embodiment, a first discharge section is provided to discharge pre-plastic blanks with defects detected by the first inspection section to the outside and a second discharge section is provided to discharge pre-plastic blanks with defects detected by the second inspection section to the outside. However, it is also possible to configure a discharge section to discharge pre-plastic blanks with defects detected by the first inspection section and pre-plastic blanks with defects detected by the second inspection section to the outside together.

[0100] In addition, in the above embodiment, the continuous conveying section 150, which is equivalent to the first conveying section, is configured to receive the inverted pre-plasticized blank 200 from the flipping section 121 of the cooling section 120, and hold and convey the pre-plasticized blank 200 in an inverted state. However, the present invention is not limited to this. It can also be configured such that the cooling section transfers the pre-plasticized blank 200 to the continuous conveying section in an upright state, and the continuous conveying section holds and conveys the pre-plasticized blank 200 in an upright state.

[0101] In this case, the camera 213 and light source 214 of the first inspection unit 210, which captures images of the bottom 202 of the preform 200, can be arranged facing upwards, for example... Figure 4 The shooting position is located directly below or below the pre-plasticized blank 200 at position P4, so as to be able to take a picture of the entire bottom of the pre-plasticized blank 200 being transported in an upright state.

[0102] Alternatively, a mechanism may be provided to cause the pre-plasticized blank 200, which is conveyed in an upright state by the continuous conveying unit 150, to flip up and down before reaching the first inspection unit 210 and pass through the first inspection unit 210 in an inverted state.

[0103] Furthermore, the embodiments disclosed herein should be considered illustrative in all respects, and not restrictive. The scope of the invention is shown not by the foregoing description but by the scope of the patent claims, and is intended to include the meaning equivalent to the scope of the patent claims and all modifications within that scope.

[0104] Symbol Explanation 100… Blow molding apparatus, 110… Injection molding section, 120… Cooling section, 130… Heating section, 140… Blow molding section, 150… Continuous conveying section (first conveying section), 160… Intermittent conveying section (second conveying section), 161… Chuck component for blow molding conveying, 200… Preform, 201… Main body, 202… Bottom, 203… Neck, 204… Top surface, 210… First inspection section, 220… Second inspection section, 230… First discharge section, 240… Second discharge section, 400… Control device, 401… First determination section, 402… First discharge control section, 403… Second determination section, 404… Second discharge control section, 500… Display device, 600… Storage device.

Claims

1. A blow molding apparatus, characterized in that, The blow molding apparatus includes: The injection molding section is used to inject a bottomed cylindrical preform made of resin. A heating section that heats the preform, which retains heat during injection molding, to a temperature suitable for blow molding; The blow molding section blow molds the heated preform to manufacture resin containers. A first conveying section holds the injection-molded preform and conveys it via the heating section; and The second conveying unit holds the pre-plasticized preform in an upright position and conveys it to the blow molding unit. The blow molding apparatus also includes: An inspection department photographs the pre-plasticized preform during transport and detects surface defects in the pre-plasticized preform based on the obtained images; and The discharge section discharges the preform with defects detected by the inspection section to the outside.

2. The blow molding apparatus according to claim 1, characterized in that, The inspection unit has: The first inspection unit takes pictures of the main body and / or bottom of the preform conveyed by the first conveying unit, and detects defects in the appearance of the preform based on the obtained images. as well as The second inspection unit takes a picture of the top surface of the neck of the preform conveyed by the second conveying unit in an upright state, and detects defects in the appearance of the preform based on the obtained image.

3. The blow molding apparatus according to claim 2, characterized in that, The discharge section has: The first discharge section discharges the pre-plasticized blank, which has been detected as defective by the first inspection section, to the outside in a manner that it is not conveyed by the second conveying section; as well as The second discharge section discharges the preform with defects detected by the second inspection section to the outside in a manner that prevents it from being blow-molded by the blow molding section.

4. A blow molding method, characterized in that, The blow molding method includes: Injection molding process, injection molding of a bottomed cylindrical preform made of resin; The heating process involves heating the preform, which retains heat during injection molding, to a temperature suitable for blow molding. The blow molding process involves blow molding the heated pre-plasticized preform to manufacture a resin container. The first conveying process involves holding the injection-molded preform and conveying it through the heating process; and The second conveying process involves receiving the pre-plasticized preform, holding it upright, and conveying it for use in the blow molding process. The blow molding method further includes: The inspection process involves photographing the pre-plasticized preform during transport and detecting surface defects in the pre-plasticized preform based on the obtained images; and The discharge process involves discharging the preform that has been found to have defects during the inspection process to the outside.

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