Blow molding device and blow molding method

Abstract

A blow molding device according to the present invention comprises: an injection molding unit for injection-molding a bottomed cylindrical preform; a heating unit for heating the preform having potential heat during injection molding; a blow molding unit for blow-molding the heated preform; a first conveyance unit for holding the injection-molded preform and conveying the preform via the heating part; and a second conveyance part for holding the conveyed preform in an upright state and conveying the preform to the blow molding unit. The blow molding device further comprises: an inspection unit for capturing an image of the preform being conveyed and detecting a defect on the appearance of the preform on the basis of the captured image; and a discharge unit for discharging the preform in which the defect has been detected to the outside.

Description

Blow molding device and blow molding method

[0001] The present invention relates to a blow molding apparatus and a blow molding method, and more particularly to a blow molding apparatus and a blow molding method that allow visual inspection of preforms within the molding apparatus.

[0002] A commonly known method for manufacturing resin containers such as PET bottles involves injection molding a raw resin material to form a cylindrical preform, and then stretching the preform by blow molding to form the shape of the container. In this process, the injection-molded preform may have defects in appearance, such as scratches, sink marks, black spots, air bubbles, or foreign matter. If the preform has defects such as a defective appearance, the container manufactured by blow molding will also have defects and cannot be sold. Therefore, it is preferable to inspect the preform before blow molding and remove defective preforms from the production line.

[0003] Conventionally, as this type of preform inspection device, a configuration has been proposed in which a sensor is used to determine whether the diameter, upper end surface, and height of the neck of the preform are good or bad (see, for example, Patent Document 1), and a configuration in which two cameras are used to detect defects in appearance along the entire circumference of the side wall of the preform (see, for example, Patent Document 2).

[0004] Japanese Patent Publication No. 6-6331 Japanese Patent Application Publication No. 11-30593 Patent No. 5563095

[0005] Blow molding machines for producing resin containers include a one-stage system (or hot parison system) that reduces energy loss by performing preform injection molding and blow molding within a single molding machine, and a two-stage system (or cold parison system) that improves production efficiency by providing separate preform injection molding and blow molding machines. The present applicant has also commercialized an injection stretch blow molding machine known as a 1.5-stage system that combines the advantages of both the one-stage and two-stage systems (see, for example, Patent Document 3). This 1.5-stage system reduces energy loss by utilizing the heat retained during injection molding to perform blow molding, while improving production efficiency by differentiating the number of preforms processed in the molding cycles of the injection molding section and the blow molding section, both of which are installed within a single molding machine.

[0006] Of the above methods, the two-stage method makes it easy to inspect the preform before feeding it into the blow molding machine, whereas the 1.5-stage method involves the steps from injection molding to blow molding being carried out continuously within a single molding machine, making it difficult to apply the conventional preform inspection device described above.

[0007] The present invention has been made in view of the above problems, and aims to provide a 1.5-stage blow molding apparatus that can perform visual inspection of preforms and efficiently eject preforms in which defects are found to the outside.

[0008] One aspect of the present invention is a blow molding apparatus comprising: an injection molding section that injection molds a bottomed cylindrical resin preform; a heating section that heats the preform, which has retained heat during injection molding, to a temperature suitable for blow molding; a blow molding section that blow molds the heated preform to produce a resin container; a first conveying section that holds the injection-molded preform and transports it via the heating section; and a second conveying section that grips the transported preform in an upright position and transports it to the blow molding section, characterized in that the blow molding apparatus further comprises an inspection section that images the preform as it is being transported and detects any defects in its appearance based on the obtained image; and a discharge section that discharges to the outside any preform for which defects have been detected by the inspection section.

[0009] According to one aspect of the present invention, it is possible to provide a 1.5-stage blow molding apparatus that can perform visual inspection of preforms and efficiently eject preforms in which defects are found to the outside.

[0010] FIG. 1 is a plan view schematically showing the configuration of a blow molding device. FIG. 2 is a diagram showing an outline of preform transportation in an injection molding section and a cooling section. FIG. 3 is a diagram showing an example of a preform. FIG. 4 is a plan view schematically showing the configuration of a first inspection section that inspects the body portion of a preform. FIG. 5 is a side view schematically showing the configuration of a first inspection section that inspects the bottom portion of a preform. FIG. 6 is a side view schematically showing the configuration of a second inspection section that inspects the top surface of the neck portion of a preform.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiments, in order to make the description easier to understand, structures and elements other than the main parts of the present invention will be described in a simplified or omitted manner. In addition, the same elements will be given the same reference numerals in the drawings. Note that the shapes, dimensions, etc. of each element shown in the drawings are shown schematically and do not represent the actual shapes, dimensions, etc.

[0012] <Description of Blow Molding Apparatus> First, a blow molding apparatus 100 according to one embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a plan view showing a schematic configuration of the blow molding apparatus. Fig. 2 is a diagram showing an outline of preform transport in the injection molding section and the cooling section.

[0013] 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 the one-stage method (hot parison method) and the two-stage method (cold parison method). The 1.5-stage blow molding method essentially produces containers by blow molding preforms that retain heat during injection molding, similar to the one-stage method. However, the blow molding cycle in the 1.5-stage method is set shorter than the preform injection molding cycle. Then, multiple preforms molded in one injection molding cycle are blow molded in multiple blow molding cycles. While not particularly limited, the ratio (N:M) of the number of preforms simultaneously injection molded (N) to the number of containers simultaneously blow molded (M) is set to, for example, 3:1.

[0014] As shown in FIG. 1 , 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. The blow molding apparatus 100 also includes a continuous conveying section (first conveying section) 150 that conveys preforms 200 discharged from the cooling section 120 to the blow molding section 140 via the heating section 130. The continuous conveying section 150 is a conveying device configured to continuously convey conveying jigs 152 that hold the preforms 200 in an inverted state along a loop-shaped conveying line 151 having multiple curved sections. In other words, the continuous conveying section 150 can repeatedly convey each conveying jig 152 along the loop-shaped conveying line 151. The blow molding apparatus 100 also includes a control device 400 that comprehensively controls 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 an I / O interface (none of which are shown), and realizes various control functions by reading and executing programs stored in the RAM or ROM. The blow molding apparatus 100 also includes a display device 500 that displays the status of the blow molding apparatus 100 to an operator or the like in accordance with commands from the control device 400, and a storage device 600 that stores data relating to the status of the blow molding apparatus 100.

[0015] The injection molding unit 110 injection-moldes a bottomed cylindrical preform 200, which is a resin molded product. As shown in Fig. 2, the injection molding unit 110 includes a neck mold (not shown) and a core mold 111 arranged above, a cavity mold 112 arranged below, and a mold clamping mechanism 114 that clamps the neck mold, core mold 111, and cavity mold 112 together using tie bars 113. The injection molding unit 110 injection-moldes the preform 200 by filling an injection space formed by the core mold 111 and the cavity mold 112 with a resin material (raw material) from an injection device (not shown).

[0016] Here, an example of a preform 200 applied in this embodiment will be described with reference to Fig. 3. Fig. 3(A) is a plan view showing the top surface (upper end surface) of the neck portion (opening) of the preform 200 in an upright state. Fig. 3(B) is a front view of the preform 200. Fig. 3(C) is a bottom view showing the hemispherical bottom portion of the preform 200.

[0017] The overall shape of the preform 200 is a cylindrical shape with one end open and the other end closed. The preform 200 includes a cylindrical body 201, a bottom 202 closing the other end of the body 201, and a neck 203 formed at the opening on one end of the body 201. The neck 203 has a circular top surface 204.

[0018] The raw material of the preform 200 is a thermoplastic synthetic resin, and can be appropriately selected depending on the application of the container. Specific types of materials include, for example, PET (polyethylene terephthalate), PEN (polyethylene naphthalate), PCTA (polycyclohexane dimethylene 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), and PLA (polylactic acid).

[0019] The injection molding unit 110 of this embodiment is configured to simultaneously mold, for example, 3 rows x N' (N' is a plurality of numbers, 4 in the example of FIG. 1 ; N is also a plurality of numbers, and when N'=4, N=12) preforms 200. The preforms 200 are molded in an upright state with their necks 203 facing upward in the injection molding unit 110, and the preforms 200 are transported in an upright state in the injection molding unit 110.

[0020] 2, the injection molding unit 110 is provided with a receiving unit 115 that removes the injection-molded preform 200 from the injection molding unit 110. The receiving unit 115 is configured to be movable in the horizontal direction (X direction in the drawing) from a receiving position below the core mold 111 to a delivery position outside the space surrounded by the tie bars 113.

[0021] The receiving section 115 holds 12 pots 300, each containing 3 rows x 4 pieces of preforms 200 molded in the injection molding section 110. Each pot 300 is an example of a preform holding member, and has a storage space corresponding to the outer shape of the preform 200.

[0022] The receiving unit 115 also includes a mechanism (not shown) that adjusts the spacing between rows of the pots 300 (spacing in the X direction in the drawing) during movement from the receiving position to the transfer position, thereby allowing the receiving unit 115 to convert the spacing between rows of the preforms 200 from the wide pitch state at the receiving position to the narrow pitch state at the transfer position.

[0023] The preforms 200 injection molded in the injection molding unit 110 are supplied from the injection molding unit 110 to the cooling unit 120. The cooling unit 120 forcibly cools the preforms 200 molded in the injection molding unit 110. The preforms 200 are transported from the cooling unit 120 in a state cooled to a predetermined temperature and continuously transported along the transport line 151. The cooling of the preforms 200 in the cooling unit 120 is performed for the purpose of eliminating temperature variations in each preform 200 after injection molding and transporting them to the heating unit 130 in a homogeneous state. In other words, the preforms 200 do not need to be cooled to room temperature and are transported to the heating unit 130 while retaining the heat from the injection molding, so that this embodiment also achieves good energy efficiency similar to that of the one-stage system.

[0024] 2, a conveying device 180 is provided between the injection molding unit 110 and the cooling unit 120, for conveying the preform 200 in an upright position from the receiving unit 115 to the cooling unit 120. The conveying device 180 includes a holding unit 181 for holding the neck portion 203 of the preform 200 in an upright position, and is configured to be able to move the holding unit 181 in the vertical direction (Z direction in the figure) and the horizontal direction (X direction in the figure) by an air cylinder (not shown).

[0025] As shown in Fig. 2, the cooling section 120 has an inverting section 121. The inverting section 121 can be inverted around an axis 122 extending in the X direction in the figure as a rotation axis, and is configured to be able to move up and down in the Z direction (up and down direction) in the figure. Twelve cooling pots 310 are arranged on each of a first surface 121a shown on the upper side of the inverting section 121 in the figure and a second surface 121b opposite the first surface 121a, in order to accommodate three rows x four preforms 200.

[0026] The cooling pots 310 arranged on the first surface 121a and the second surface 121b of the inverting section 121 are cooled by a refrigerant circulating through a refrigerant passage (not shown) provided in the inverting section 121. The cooling pots 310 of the inverting section 121 also have the function of sucking and holding the accommodated preforms 200.

[0027] Furthermore, the inverting unit 121 inverts the upright preforms 200 received from the transport device 180 into an inverted state with the necks 203 facing downward during the cooling time. The inverted preforms 200 are then delivered to transport jigs 152 of the continuous transport unit 150, which are arranged in multiple rows in a standby position below the cooling unit 120. The transport jigs 152 holding the preforms 200 are transported sequentially along the transport line 151 by the driving force of sprockets 154 or the like.

[0028] The heating section 130 heats the inverted preforms 200, which are continuously conveyed by the continuous conveying section 150, to a temperature suitable for stretching. The heating section 130 is equipped with a plurality of heaters (not shown) arranged at predetermined intervals along the conveying line 151 on both sides of the conveying line 151. Within the heating section 130, the inverted preforms 200 are heated while rotating around their axial direction, so that the entire preforms 200 are uniformly heated.

[0029] The blow molding apparatus 100 also includes an intermittent conveying section (second conveying section) 160 and a delivery section 170 downstream of the heating section 130 on the conveying line 151. The intermittent conveying section 160 holds a plurality of preforms 200 (M pieces, for example, three or four pieces) heated by the heating section 130 in an upright position and delivers them intermittently to the blow molding section 140. The delivery section 170 inverts the preforms 200 that have been continuously conveyed in an inverted position along the conveying line 151 by the continuous conveying section 150, and delivers them to the intermittent conveying section 160 in an upright position.

[0030] In this embodiment, a plurality (M') of conveying jigs 152 are connected in series in the conveying direction by connecting members (not shown) and are unitized (integrated). The aforementioned "plurality (M')" indicates a number equal to or greater than M, such as 8, 9, or 12. When the preforms 200 or containers are large (e.g., containers with a capacity of 12 liters or more and their preforms), the preforms 200 may be arranged on the unitized conveying jigs 152 in an interval of one to three. The continuous conveying unit 150 supplies a plurality (M, e.g., three or four) of preforms 200 at a time to the delivery unit 170 by repeatedly driving and stopping the sprocket 154a on the conveying line 151 downstream of the curved conveying unit 155, which curves at a predetermined radius.

[0031] The delivery section 170 is provided with an inverting device (not shown) at the delivery position P0. The preforms 200 transported in an inverted state along the transport line 151 are inverted by the inverting device arranged above the preforms 200 at the delivery position P0 to become upright. The delivery section 170 is also provided with, for example, an elevating device (not shown) that raises and lowers the inverting device, and delivers the upright preforms 200 to the intermittent transport section 160 in a state where they have been raised to a predetermined position (delivery position P1).

[0032] The intermittent conveying section 160 grips the neck portion 203 of each upright preform 200 with an openable and closable blow conveying chuck member 161 provided in the intermittent conveying section 160. This blow conveying chuck member 161 grips the neck portion 203 of the preform 200 at a delivery position P1 located above the delivery position P0, and moves the preform 200 from the delivery position P1 to the blow molding position P2. In this way, multiple preforms 200 are conveyed to the blow molding section 140 at predetermined intervals.

[0033] The blow molding section 140 includes a pair of split blow cavity molds 141 corresponding to the shape of the container, and an air introduction member (not shown) that also serves as a stretch rod. In the blow molding section 140, the intermittent conveying section 160 conveys a predetermined number of preforms 200 received from the delivery section 170 to the blow cavity molds 141, and the preforms 200 are stretch-blow molded in the blow cavity molds 141 to manufacture containers. The containers manufactured in the blow molding section 140 are conveyed by the intermittent conveying section 160 to a container removal position P3 (removal section) outside the blow molding section 140.

[0034] <Description of Inspection Unit and Discharge Unit> Next, with reference to FIGS. 4 to 6, configuration 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. Note that 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. As will be described later, the inspection unit in this embodiment images the preform 200 being transported and detects appearance defects in the body portion 201, bottom portion 202, and neck portion 203 of the preform 200 based on the obtained image. Furthermore, the discharge unit in this embodiment efficiently discharges preforms 200 for which appearance defects have been detected by the inspection unit to the outside of the blow molding apparatus 100.

[0035] The configuration of the first inspection section 210 in this embodiment will be described with reference to Figures 4 and 5. Figure 4 is a plan view schematically showing the configuration of the first inspection section 210 that inspects the body section 201 of the preform 200, and Figure 5 is a side view schematically showing the configuration of the first inspection section 210 that inspects the bottom section 202 of the preform 200.

[0036] In this embodiment, the first inspection section 210 is provided downstream of the heating section 130 in the continuous conveying section 150, i.e., in the vicinity of the curved conveying section 155. The first inspection section 210 is equipped with at least one, preferably two, cameras 211, 211 that capture images of the body portion 201 of the preform 200 conveyed in an inverted state, and light sources 212, 212 for these cameras 211, 211. The first inspection section 210 also is equipped with one camera 213 that captures images of the bottom portion 202 of the preform 200 conveyed in an inverted state, and a light source 214 for this camera 213. Furthermore, the first inspection section 210 is equipped with a first determination section 401 that determines the presence or absence of defects in the appearance of the preform 200 based on information about images captured by the cameras 211, 211 and the camera 213. The first inspection unit 210 also includes a display unit for displaying the results of this determination to inform the operator of the apparatus of the determination result, and a memory unit for saving images of the preform 200 in which a defect has been detected. In this embodiment, the display unit 500 and memory unit 600 of the blow molding apparatus 100 function as the display unit and memory unit, respectively.

[0037] The cameras 211, 211 may be any cameras capable of capturing visible light, and known CCD cameras or CMOS cameras may be used. As shown in Figure 4, the cameras 211, 211 capture an image of the body portion 201 of the preform 200 when the preform 200, which is transported in an inverted state along the transport line 151 of the continuous transport unit 150, reaches a predetermined position (imaging position P4). Each of the two cameras 211, 211 is positioned so that its optical axis forms an angle of approximately 90 degrees on a plane perpendicular to the central axis of the preform 200. This allows the cameras 211, 211 to capture an image of almost the entire circumference of the body portion 201 of the preform 200.

[0038] The light sources 212, 212 for the cameras 211, 211 are arranged on opposite sides of the cameras 211, 211 with the preform 200 in between, and illuminate the preform 200 when the cameras 211, 211 are taking an image, thereby enabling the capture of a clear image. The light sources 212, 212 for the cameras 211, 211 are not particularly limited as long as they are lighting devices that have a sufficient amount of light to properly capture an image of the preform 200 with the cameras 211, 211. For example, a planar LED light having a height and width approximately the same as the height and width of the preform 200 can be used.

[0039] Like the cameras 211, 211, the camera 213 can be configured as a known camera (CCD camera or CMOS camera) capable of capturing visible light. As shown in Figures 4 and 5, the camera 213 captures an image of the bottom 202 of the preform 200 when the preform 200, which is transported in an inverted state along the transport line 151 of the continuous transport unit 150, reaches the imaging position P4. The camera 213 is disposed, for example, in a position directly above the preform 200 at the imaging position P4 so that the entire bottom of the preform 200 can be captured.

[0040] The light source 214 for the camera 213 is disposed, for example, directly below or below the camera 213 so as to be able to thoroughly illuminate the bottom 202 of the preform 200. 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 fall within the angle of view of the camera 213. The light source 214 may be provided in a position such that it illuminates the bottom 202 of the preform 200 at the imaging position P4 from directly above or from above, or multiple light sources 214 may be provided.

[0041] The first determination unit 401 is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and an I / O interface (none of which are shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the first determination unit 401 and realizes its function by reading and executing a program stored in the RAM or ROM. The first determination unit 401 receives image data of the preform 200 captured by the cameras 211, 211, and 213, and determines whether or not there are any defects in the appearance of the preform 200 based on this image data using a known algorithm. For example, this determination involves performing image processing such as edge detection on the collected image data, and determining that there is a defect if, for example, there is an edge detected other than the outline of a normal preform 200. This allows preforms 200 having defects such as black spots, air bubbles, or foreign matter in the body portion 201 or bottom portion 202 to be identified.

[0042] The determination result by the first determination unit 401 is displayed on the display device 500, allowing an operator of the blow molding apparatus 100 to know the inspection result. The display device 500 is, for example, a display device such as a liquid crystal display panel, an organic EL display panel, or an operation screen provided in a part of the blow molding apparatus 100. The display device 500 displays a predetermined screen based on the control of the first determination unit 401.

[0043] The judgment results displayed on the display device 500 can be in the form of a list including, for example, image data captured by the first inspection unit 210, the presence or absence of defects, identification information for the preform 200, identification information for the transport jig 152, the date and time of the inspection, and the location and type of defects. This information is stored in the storage device 600. The storage device 600 can be configured, for example, by a storage device such as an HDD or SSD provided inside the blow molding apparatus 100. The storage device 600 may also be provided outside the blow molding apparatus 100.

[0044] The preform 200 for which a defect has been detected by the first inspection section 210 is discharged to the outside by the first discharge section 230. The first discharge section 230 is provided, for example, on the conveyance line 151 downstream of the intermittent conveyance section 160 and the delivery section 170, and has a first discharge mechanism for discharging the preform 200 held by the conveyance jig 152 to the outside from a first discharge port (not shown).

[0045] Furthermore, the control of the delivery unit 170 and the first discharge mechanism in the first discharge unit 230 for discharging the preform 200, for which a defect has been detected by the first inspection unit 210, from the first discharge port is performed by a first discharge control unit 402. The first discharge control unit 402 is configured as an information processing device such as a microcomputer including a CPU, RAM, ROM, and an I / O interface (none of which are shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the first discharge control unit 402, and realizes the function of the first discharge control unit 402 by reading and executing a program stored in the RAM or ROM.

[0046] The first discharge control unit 402 receives information about the preform 200 in which a defect was detected by the first inspection unit 210 from the first inspection unit 210. Then, when the preform 200 in which the defect was detected flows along the conveying line 151 and reaches the delivery position P0, the first discharge control unit 402 controls the delivery unit 170 so that the delivery unit 170 does not deliver the preform 200 to the intermittent conveying unit 160. As a result, the preform 200 in which the defect was detected is left on the conveying line 151 without being conveyed to the blow molding unit 140. The preform 200 in which the defect was detected is then conveyed to the first discharge unit 230 together with the conveying jig 152, which is returned to the standby position below the cooling unit 120. The preform 200 that has reached the first discharge unit 230 is discharged to the outside through a first discharge port by a first discharge mechanism of the first discharge unit 230.

[0047] In this embodiment, in order to avoid complicating the control and mechanism, a predetermined number (M') of preforms 200 held by the connected conveying jigs 152 are considered to be one set, and the carry-out process when a defect is detected is performed on a set-by-set basis. In other words, if a defect is detected in one of the set (M') of preforms 200 held by the connected conveying jigs 152, the same process as for the preform 200 in which the defect was detected is performed on the other preforms 200 included in that set, regardless of whether they have a defect or not. In other words, the one set of preforms 200 is not transferred to the intermittent conveying section 160 but is conveyed to the first discharge section 230 and discharged to the outside.

[0048] Next, the configuration of the second inspection section 220 in this embodiment will be described with reference to Fig. 6. Fig. 6 is a side view schematically showing the configuration of the second inspection section 220 that inspects the top surface 204 of the neck portion 203 of the preform 200.

[0049] In this embodiment, the second inspection section 220 is provided between the delivery position P1 and the blow molding position P2 in the intermittent conveying section 160. The second inspection section 220 includes a camera 215 that captures an image of the top surface 204 of the neck portion 203 of the preform 200 being conveyed in an upright state, and a light source 216 for this camera 215. The second inspection section 220 also includes a second judgment section 403 that judges the presence or absence of an external defect in the preform 200 based on information about the image captured by the camera 215. The second inspection section 220 also includes a display section for displaying the result of this judgment to inform the operator of the apparatus of the judgment result, and a memory section for saving images of the preform 200 in which a defect has been detected. In this embodiment, the display device 500 and memory device 600 of the blow molding apparatus 100 function as these display section and memory section, respectively.

[0050] The camera 215 can be configured as a known camera capable of capturing visible light images, similar to the cameras 211, 211, and 213. As shown in Fig. 6, the camera 215 is provided above a path along which the upright preform 200 gripped by the blow conveying chuck member 161 of the intermittent conveying section 160 moves from the delivery position P1 to the blow molding position P2, and captures an image of the top surface 204 of the neck portion 203 of the preform 200 passing directly below it.

[0051] In this embodiment, the blow conveying chuck member 161 is configured to grip a plurality (M) of preforms 200 per unit, and accordingly, at least one, preferably M, cameras 215 are provided on a frame member (not shown) located above the blow conveying chuck member 161. When the number of containers to be molded simultaneously is three (M=3), each of the three (M) cameras 215 is associated with one of the three (M) preforms 200 gripped by the blow conveying chuck member 161, making it possible to inspect three (M) preforms 200 at a time, thereby shortening the time required for inspection in the second inspection section 220.

[0052] The light source 216 for the camera 215, like the light source 214 for the camera 213, is arranged directly below or below the camera 215, and is configured as a ring-shaped LED light so that the light source 216 does not enter the angle of view of the camera 215. The light source 216 may be provided in a position such that it illuminates the top surface 204 of the preform 200 from directly above or above.

[0053] Like the first determination unit 401 of the first inspection unit 210, the second determination unit 403 is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and I / O interface (none of which are shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the second determination unit 403 and realizes its function by reading and executing a program stored in RAM or ROM. The second determination unit 403 receives image data of the preform 200 captured by the camera 215 and, based on this image data, determines whether or not there is a defect in the appearance of the preform 200 using a known algorithm. For example, this determination involves performing image processing such as edge detection on the collected image data, and determining that there is a defect if there is an edge detected other than the outline of a normal preform. This allows preforms 200 having defects, such as scratches or sink marks, on the top surface 204 of the neck portion 203 to be identified.

[0054] The determination result by the second determination unit 403 is displayed on the display device 500, so that an operator of the blow molding apparatus 100 or the like can know the inspection result. The display device 500 displays a predetermined screen based on the control of the second determination unit 403.

[0055] The judgment results displayed on display device 500, like the judgment results in first inspection section 210, can be in the form of a list including information such as image data captured by second inspection section 220, the presence or absence of defects, identification information for preform 200, identification information for blow conveying chuck member 161, inspection date and time, and the location and type of defects. In addition, this information is saved in storage device 600. As described above, storage device 600 can be configured with a storage device such as an HDD or SSD provided inside blow molding apparatus 100, or may be provided outside blow molding apparatus 100.

[0056] The preform 200 for which a defect has been detected by the second inspection section 220 is discharged to the outside by the second discharge section 240. The second discharge section 240 is provided, for example, at or near a take-out position P3 outside the blow molding section 140 in the intermittent conveying section 160, and has a second discharge mechanism for discharging the preform 200 gripped by the blow conveying chuck member 161 to the outside through a second discharge port (not shown).

[0057] Furthermore, the control of the blow conveying chuck member 161 and the blow molding unit 140 in the second discharge unit 240 for discharging the preform 200, for which a defect has been detected by the second inspection unit 220, from the second discharge port is performed by a second discharge control unit 404. The second discharge control unit 404, like the first discharge control unit 402, is configured as an information processing device such as a microcomputer equipped with a CPU, RAM, ROM, and an I / O interface (none of which are shown). In this embodiment, the control device 400 of the blow molding apparatus 100 functions as the second discharge control unit 404, and realizes the function of the second discharge control unit 404 by reading and executing a program stored in the RAM or ROM.

[0058] The second discharge control unit 404 receives information about the preform 200 in which a defect was detected in the second inspection unit 220, and when the preform 200 in which the defect was detected is transported by the intermittent transport unit 160 and reaches the blow molding position P2, controls the blow molding unit 140 so that blow molding is not performed by the blow molding unit 140. Note that the blow molding unit 140 does not introduce blow air into the preform 200 in which a defect was detected in the second inspection unit 220, thereby suppressing unnecessary consumption of blow air.

[0059] As a result, the preform 200 in which a defect has been detected continues to be gripped by the blow conveying chuck member 161 without being molded into a container, and is conveyed to the second discharge section 240 by the intermittent conveying section 160. The preform 200 that has reached the second discharge section 240 is discharged to the outside through the second discharge port by the second discharge mechanism of the second discharge section 240.

[0060] In this embodiment, in order to avoid complicating the control and mechanism, a predetermined number (M) of preforms 200 held by the blow conveying chuck member 161 are considered to be one set, and the carry-out process when a defect is detected is performed on a set-by-set basis. In other words, if a defect is detected in any of the preforms 200 in one set held by the blow conveying chuck member 161, the same process as for the preform 200 in which the defect was detected is performed on the other preforms 200 in that set, regardless of whether they have a defect or not. In other words, the one set of preforms 200 is transported to the second discharge section 240 without being blow-molded and is discharged to the outside.

[0061] The effects of this embodiment will be described below. According to this embodiment, in a blow molding machine 100 that performs an integrated process from injection molding of a preform 200 to blow molding of a container, images of the preform 200 are taken of the preform 200 during transport, and based on the obtained images, visual defects in the body 201, bottom 202, and neck 203 of the preform 200 can be detected, and preforms 200 for which defects have been detected can be efficiently discharged to the outside. Therefore, in a 1.5-stage blow molding device, visual inspection is performed on the preforms 200 before blow molding, and defective preforms 200 can be discharged to the outside without being blow molded. This allows defective products to be discovered early, eliminating wasted machine operation and improving container production efficiency.

[0062] Furthermore, inspection of the preform 200 is performed by a first inspection section 210 that performs an external inspection of the body 201 and bottom 202 of the transported preform 200, and a second inspection section 220 that performs an external inspection of the top surface 204 of the neck 203 of the preform 200 that is transported in an upright position. Therefore, even in a 1.5-stage blow molding device in which the preform is likely to be flipped over or moved up and down frequently, an external inspection can be efficiently performed in accordance with the transport state of the preform 200.

[0063] Furthermore, preforms 200 in which defects have been detected are discharged to the outside by a first discharge section 230 which discharges preforms 200 in which defects have been detected by the first inspection section 210 while being transported by the continuous transport section (first transport section) 150 to the outside without handing them over to the intermittent transport section (second transport section) 160, and a second discharge section 240 which discharges preforms 200 in which defects have been detected by the second inspection section 220 while being transported by the intermittent transport section 160 to the outside without blow molding by the blow molding section 140. This eliminates the need to waste machine operation on defective preforms 200 and allows them to be efficiently discharged to the outside.

[0064] The present invention is not limited to the above-described embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention. For example, in the above-described embodiment, a first inspection unit that performs a visual inspection of the body and bottom of the preform and a second inspection unit that performs a visual inspection of the top surface of the neck of the preform are provided separately, but it is also possible to provide an inspection unit that performs a visual inspection of the body, bottom, and top surface of the neck of the preform all at once.

[0065] Furthermore, in the above embodiment, a first discharge section that discharges preforms for which defects have been detected by the first inspection section to the outside, and a second discharge section that discharges preforms for which defects have been detected by the second inspection section to the outside are provided separately, but it is also possible to provide a configuration in which a discharge section is provided that discharges preforms for which defects have been detected by the first inspection section and preforms for which defects have been detected by the second inspection section to the outside all at once.

[0066] In the above embodiment, the continuous conveying unit 150, which corresponds to the first conveying unit, is configured to receive the inverted preform 200 from the inverting unit 121 of the cooling unit 120 and hold and convey the preform 200 in the inverted state. However, the present invention is not limited to this. The cooling unit may deliver the preform 200 to the continuous conveying unit in an upright state, and the continuous conveying unit may hold and convey the preform 200 in the upright state. In this case, the camera 213 and light source 214 of the first inspection unit 210, which capture an image of the bottom 202 of the preform 200, can be positioned facing upward, for example, directly below or below the preform 200 at the imaging position P4 in FIG. 4, so that the entire bottom of the preform 200 conveyed in the upright state can be imaged. Alternatively, a mechanism may be provided to invert the preform 200 conveyed in the upright state by the continuous conveying unit 150 upside down just before the first inspection unit 210 and pass through the first inspection unit 210 in an inverted state.

[0067] Furthermore, the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0068] DESCRIPTION OF SYMBOLS 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...blow conveying chuck member, 200...preform, 201...body section, 202...bottom section, 203...neck section, 204...top surface, 210...first inspection section, 220...second inspection section, 230...first discharge section, 240...second discharge section, 400...control device, 401...first judgment section, 402...first discharge control section, 403...second judgment section, 404...second discharge control section, 500...display device, 600...storage device

Claims

1. A blow molding apparatus comprising: an injection molding section which injection molds a bottomed cylindrical resin preform; a heating section which heats the preform, which has retained heat during injection molding, to a temperature suitable for blow molding; a blow molding section which blow molds the heated preform to produce a resin container; a first transport section which holds the injection molded preform and transports it via the heating section; and a second transport section which holds the transported preform in an upright position and transports it to the blow molding section, further comprising: an inspection section which images the preform during transport and detects appearance defects of the preform based on the obtained image; and a discharge section which discharges to the outside the preform for which defects have been detected by the inspection section.

2. The blow molding apparatus according to claim 1, characterized in that the inspection section comprises: a first inspection section that images the body and / or bottom of the preform transported by the first transport section and detects any defects in appearance of the preform based on the obtained image; and a second inspection section that images the top surface of the neck of the preform transported in an upright state by the second transport section and detects any defects in appearance of the preform based on the obtained image.

3. The blow molding apparatus according to claim 2, characterized in that the discharge section comprises: a first discharge section which discharges to the outside the preform in which a defect has been detected by the first inspection section without transporting it by the second transport section; and a second discharge section which discharges to the outside the preform in which a defect has been detected by the second inspection section without blow molding it in the blow molding section.

4. A blow molding method comprising: an injection molding step of injection molding a bottomed cylindrical resin preform; a heating step of heating the preform, which has retained heat from injection molding, to a temperature suitable for blow molding; a blow molding step of blow molding the heated preform to produce a resin container; a first transport step of holding the injection-molded preform and transporting it through the heating step; and a second transport step of receiving the transported preform, holding it in an upright position, and transporting it for the blow molding step, characterized in that the blow molding method further comprises an inspection step of imaging the preform during transport and detecting appearance defects of the preform based on the obtained image; and a discharge step of discharging to the outside the preform in which defects were detected in the inspection step.

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