Blow molding device and method for controlling blow molding device

Abstract

This blow molding device comprises: an injection molding part for injection-molding a resin preform; a cooling part for cooling the preform after injection molding; a heating part for heating the cooled preform; and a blow molding part for blow-molding the heated preform. The blow molding device further includes: a preform discharge part configured such that the preform before the heating can be discharged to the outside, and a control unit for performing control for switching an operation mode of the blow molding device between a normal operation mode and a preform discharge mode. In the normal operation mode, the injection-molded preform is moved to the blow molding part through the cooling part and the heating part to perform blow molding, and in the preform discharge mode, control for discharging the injection-molded preform from the preform discharge part to the outside is performed.

Description

Blow molding apparatus and control method for blow molding apparatus

[0001] The present invention relates to a blow molding apparatus and a method for controlling a blow molding apparatus.

[0002] BACKGROUND ART Conventionally, there are known blow molding apparatuses for resin containers, which are known as a one-stage system or hot parison system, and a two-stage system or cold parison system.

[0003] The one-stage method is a molding method in which the injection molding of preforms and the blow molding of containers are carried out in a single molding machine. With this method, the preforms injection-molded in the injection molding section are blow-molded while retaining the heat retained during injection molding, which has the advantage of minimizing energy waste and requiring only one machine.

[0004] On the other hand, the two-stage method is a molding method in which the preform injection molding machine and the container blow molding machine are installed separately, and the preform injection molding and blow molding are performed offline (separate machines, not directly connected to each other). Preforms injection-molded in the injection molding machine are naturally cooled and then stored as intermediate inventory. The stored preforms are then supplied to the blow molding machine, reheated to the appropriate temperature for blowing, and then blow-molded. In this method, the injection molding cycle and blow molding cycle are independent, making it easy to set the injection and temperature conditions separately. However, the need to reheat the injection-molded preforms after cooling them once poses a challenge in terms of energy efficiency.

[0005] The present applicant has put into practical use 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 1). This 1.5-stage system utilizes the heat generated during injection molding, as with the one-stage system, while adjusting the temperature of the preforms by reheating. The temperature-adjusted preforms are then divided into M preforms, which is fewer than the number N molded in one injection molding cycle, and each M preforms is blow-molded as one cycle. This improves production efficiency while reducing energy waste.

[0006] Patent No. 5563095

[0007] For example, a blow molding machine for producing beverage bottles may be connected to external devices, such as a bottle inspection machine, a bottle sterilizer, a rinser, a filler, and a capping machine, which perform various processes from post-bottle inspection to filling and capping. In such an inline (direct-connected) production line, the production volume of containers in the blow molding machine must be coordinated with the throughput of downstream devices, and if a malfunction or other problem occurs in the downstream device and operation is stopped, operation of the blow molding machine must also be stopped. Offline (non-direct-connected) production lines, which do not connect the blow molding machine to external devices, are highly flexible, but require storage devices, alignment devices, conveying devices, etc. for molded products (containers, preforms, etc.) between processes / machines, requiring a larger installation area than inline production lines (reducing area productivity).

[0008] However, with a 1.5-stage blow molding machine, when restarting after stopping operation, it is necessary to readjust the settings of the injection molding conditions, heating conditions, conveying conditions, blow molding conditions, etc., which takes a certain amount of time. Because this readjustment must be performed while the machine is actually operating, preforms injection-molded until the adjustment is completed often have to be discarded due to molding defects, resulting in a problem of wasted resin material. In particular, a 1.5-stage blow molding machine produces a larger number of preforms per injection molding run than a 1-stage machine, so the amount of preforms discarded in such cases tends to be larger.

[0009] The present invention has been made in view of the above problems, and has as its object to reduce the amount of preforms discarded during adjustment work of a 1.5 stage type blow molding machine.

[0010] One aspect of the present invention is a blow molding apparatus comprising an injection molding section that injection molds resin preforms, a cooling section that cools the preforms, which have heat retained during injection molding, to a predetermined temperature, a heating section that continuously transports and heats the cooled preforms, and a blow molding section that blow molds the heated preforms to produce resin containers, further comprising a preform discharge section that is configured to be able to discharge preforms to the outside before they are heated by the heating section, and a control section that controls the operating mode of the blow molding apparatus to switch between a normal operation mode and a preform discharge mode, wherein in the normal operation mode, the injection-molded preforms are controlled to be moved via the cooling section and the heating section to the blow molding section and blow-molded, and in the preform discharge mode, the injection-molded preforms are controlled to be discharged from the preform discharge section to the outside.

[0011] According to one aspect of the present invention, in a 1.5 stage blow molding machine, the amount of preforms discarded during adjustment work of the machine can be reduced.

[0012] It is a plan view showing a schematic configuration of the blow molding apparatus. It is a diagram showing an outline of the transport of preforms in the injection molding section and the cooling section. It is a block diagram showing the configuration of a control system of the blow molding apparatus. It is a flowchart showing the control process of switching between operation modes. It is a diagram showing an example of an operation mode selection screen in the interface section.

[0013] 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.

[0014] <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.

[0015] 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.

[0016] 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 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 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.

[0017] The blow molding apparatus 100 also includes a preform discharge section 210 that can discharge the injection-molded preform 200 to the outside without transporting it to the heating section 130, and a preform input section 220 that can input the previously injection-molded preform 200 from the outside into the cooling section 120. The blow molding apparatus 100 also includes a control section 400 that controls switching of the operation mode of the blow molding apparatus 100, which will be described later, and an interface section 410 that receives input of an instruction to switch the operation mode from an operator of the blow molding apparatus 100 (hereinafter simply referred to as the "operator"). The blow molding apparatus 100 also includes a temperature detection section 420 that can detect the temperature of the heating section 130, and an operation status detection section 430 that can detect the operation status of an external device (not shown) connected to the blow molding apparatus 100 downstream of the blow molding apparatus 100.

[0018] The injection molding unit 110 injection molds 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).

[0019] Here, an example of a preform 200 used in this embodiment will be described. The overall shape of the preform 200 is a cylindrical shape with one end open and the other end closed and closed. 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 Co.), 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).

[0020] 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, so when N'=4, N=12) preforms 200. In addition, in the injection molding unit 110, the preforms 200 are molded and transported in an upright state with the neck portion provided on one open end facing upward.

[0021] 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.

[0022] 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. Each pot 300 is cooled to a predetermined temperature by a refrigerant circulating through a refrigerant passage (not shown) provided in the receiving section 115. In this embodiment, this predetermined temperature is set to a temperature at which the injection-molded preforms 200 can stably maintain their shape.

[0023] 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.

[0024] 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.

[0025] As shown in FIG. 2 , a conveying device 180 is provided between the injection molding unit 110 and the cooling unit 120 to convey 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 that holds the neck of the upright preform 200, and is configured to move the holding unit 181 vertically (Z direction in the figure) and horizontally (X direction in the figure) using an air cylinder (not shown). In this embodiment, the conveying device 180 also functions as a preform discharge unit 210. As will be described later, when the operation mode of the blow molding apparatus 100 is set to the preform discharge mode, the conveying device 180 as the preform discharge unit 210 is configured to be movable to a discharge position (not shown) from which the preform 200 can be discharged to the outside through a discharge port (not shown).

[0026] As shown in FIG. 2 , the cooling section 120 has an inverting section 121. The inverting section 121 is invertible around a shaft 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 and a second surface 121b opposite the first surface 121a to accommodate three rows of four preforms 200. In this embodiment, the inverting section 121 also functions as a preform insertion section 220. As described below, the inverting section 121 as the preform insertion section 220 is configured to be movable to an insertion position (not shown) where preforms 200 can be inserted from outside when the operation mode of the blow molding apparatus 100 is set to the preform insertion mode.

[0027] 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.

[0028] Furthermore, the inverting unit 121 inverts the upright preforms 200 received from the transport device 180 into an inverted state with the necks 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 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.

[0029] 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.

[0030] The blow molding apparatus 100 also includes an intermittent 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 (M pieces, for example, three pieces) preforms 200 heated by the heating section 130 and delivers them intermittently to the blow molding section 140. The delivery section 170 delivers the preforms 200 continuously delivered by the continuous conveying section 150 from the conveying line 151 to the intermittent conveying section 160.

[0031] 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.

[0032] 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).

[0033] The intermittent conveying section 160 grips the neck portion of each upright preform 200 with an openable and closable blow conveying chuck member (not shown) provided in the intermittent conveying section 160. This blow conveying chuck member grips the neck portion 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.

[0034] 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.

[0035] The preform discharge section 210 includes the above-mentioned conveying device 180 and a discharge port (not shown). The operation of the preform discharge section 210 is controlled by the control section 400. As will be described later, when the operation mode of the blow molding apparatus 100 is switched to the preform discharge mode, the conveying device 180 moves the preforms 200 received from the receiving section 115 to the above-mentioned discharge position rather than handing them over to the cooling section 120. The preform discharge section 210 then discharges the preforms 200 to the outside of the blow molding apparatus 100 through the discharge port. A safety door is provided at the discharge port, and this safety door is configured to be able to open only when the operation mode of the blow molding apparatus 100 is switched to the preform discharge mode and the conveying device 180 has moved to the discharge position.

[0036] The preform input section 220 includes the above-described reversing section 121 and an input port (not shown). The operation of the preform input section 220 is controlled by the control section 400. As will be described later, when the operation mode of the blow molding apparatus 100 is switched to the preform input mode, the reversing section 121 moves to the above-described input position. An operator or a preform carrying device can input a preform 200 that has been injection-molded in advance into the reversing section 121 that has moved to the input position through the input port. The preform 200 is input by manually or mechanically inserting the preform 200 into the cooling pot 310 of the reversing section 121. A safety door is provided at the input port, and this safety door is configured to be openable only when the operation mode of the blow molding apparatus 100 is switched to the preform input mode and the reversing section 121 has moved to the input position.

[0037] The interface unit 410 has an input unit (not shown) that accepts operational input from an operator, and a display unit (not shown) that displays various settings and operating states of the blow molding apparatus 100 to the operator. The input unit is, for example, a touch panel or input buttons that accept operational input from the operator. The operator uses the input unit to input instructions, etc., and the interface unit 410 accepts the instructions, etc. from the operator. The display unit is, for example, a display device such as a liquid crystal display panel or an organic EL display panel. The display unit displays a predetermined screen based on the control of the control unit 400, which will be described later. Note that the interface unit 410 may have a structure in which the display unit and the input unit are integrated, such as a touch panel. The interface unit 410 is configured to transmit an operation mode switching instruction input by the operator to the control unit 400, as will be described later.

[0038] The temperature detection unit 420 is a temperature sensor that is provided near the heating unit 130 and detects the temperature near the outlet of the heating unit 130. The temperature detection unit 420 is configured to transmit information indicating the detected temperature of the heating unit 130 to the control unit 400.

[0039] The operating status detection unit 430 receives a signal indicating the operating status of an external device from an external device (not shown) connected to the blow molding apparatus 100 downstream of the blow molding apparatus 100 and transmits the signal to the control unit 400. Here, the external device connected to the blow molding apparatus 100 is, for example, a device that performs each process from inspecting and cleaning the resin containers manufactured by the blow molding apparatus 100 to filling the containers with contents (e.g., beverages) and capping. The external device may be, for example, a bottle inspection machine, a bottle sterilizer, a rinser, a filling machine, a capping machine, etc. The operating status detection unit 430 is configured to detect an abnormality in the external device when an abnormality occurs in the external device, for example, when a part of the external device stops operating due to a malfunction. The control unit 400 may also be configured to have the function of an operating status detection unit, so that the control unit 400 directly receives a signal regarding the operating status of the external device.

[0040] 3 shows an example of the configuration of a control system for the blow molding apparatus 100. The control unit 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). The control unit 400 reads and executes programs stored in the RAM or ROM to comprehensively control the operation of the blow molding apparatus 100 and also functions as an operation mode setting unit 401. The control unit 400 receives a signal indicating an operation mode switching instruction from the interface unit 410, a signal indicating the temperature of the heating unit 130 from the temperature detection unit 420, and a signal indicating the operating status of an external device from the operation status detection unit 430. Based on these signals received by the control unit 400, the operation mode setting unit 401 performs operation mode switching control to switch and set the operation mode of the blow molding apparatus 100 to one of a normal operation mode, a preform discharge mode, and a preform introduction mode under predetermined conditions, which will be described later.

[0041] <Explanation of Operation Mode Switching Control> Each process of the operation mode switching control by the operation mode setting unit 401 will be described with reference to Fig. 4. Fig. 4 is a flowchart showing the control process of operation mode switching in this embodiment. This process may be automatically and repeatedly executed at predetermined time intervals when the blow molding apparatus 100 is in a normal operating state, or may be executed in response to an operator operating the interface unit 410 when an abnormality occurs in the production line.

[0042] In step 1 (denoted as "S1"; the same applies below) of this process, the operation mode setting unit 401 determines whether or not an abnormality has occurred in the operating status of the blow molding apparatus 100. This determination is made based on, for example, a signal indicating the temperature of the heating unit 130 detected by the temperature detection unit 420, or a signal indicating the operating status of an external device detected by the operating status detection unit 430.

[0043] In the determination using the temperature information of the heating section 130, for example, if the detected temperature of the heating section 130 is not within a predetermined temperature range, it is determined that an abnormality has occurred. This predetermined temperature range can be set as a temperature range that allows the preforms 200 transported through the heating section 130 to be heated to a temperature suitable for subsequent blow molding, and can be set to, for example, 70 to 110°C. This predetermined temperature range can be changed as appropriate depending on the design of the temperature conditions of the preforms 200 before they are transported to the heating section 130.

[0044] If the determination result in step 1 is NO, and it is determined that no abnormality has occurred in the operating status of the blow molding apparatus 100, the process proceeds to step 5, where the operating mode setting unit 401 controls the blow molding apparatus 100 to set the operating mode to the normal operating mode, and this process ends. In the normal operating mode, as described above, the injection-molded preform 200 is transported to the blow molding unit 140 via the cooling unit 120 and the heating unit 130, and a resin container is manufactured by blow molding.

[0045] If the determination result in step 1 is YES, and it is determined that an abnormality has occurred in the operating status of the blow molding apparatus 100, the process proceeds to step 2. In step 2, the operation mode setting unit 401 determines whether or not an operation mode switching instruction has been input to the interface unit 410 from the operator. FIG. 5 is a diagram showing an example of an operation mode selection screen displayed on the display unit of the interface unit 410. This operation mode selection screen 411 is configured as a screen to which the operator transitions when, for example, the operator selects an operation mode switching tab 412 on the setting screen displayed on the display unit. The operation mode selection screen 411 displays a preform discharge mode selection icon 413 and a preform loading mode selection icon 414. The operator can input an operation mode switching instruction by selecting either of these icons 413 or 414.

[0046] If the determination result in step 2 is NO and the input of an operation mode switching instruction is not confirmed, the process proceeds to step 5, where the operation mode of the blow molding apparatus 100 is set to the normal operation mode under the control of the operation mode setting unit 401, and this process ends. On the other hand, if the determination result in step 2 is YES and the input of an operation mode switching instruction is confirmed, the process proceeds to step 3. In step 3, it is determined whether the input operation mode switching instruction is an instruction to switch to the preform discharge mode or an instruction to switch to the preform introduction mode.

[0047] Here, the preform discharge mode is an operating mode in which the preforms 200 injection molded in the injection molding section 110 are discharged to the outside without being transported to the cooling section 120. When the preform discharge mode is selected, the conveying device 180 functioning as the preform discharge section 210 moves the preforms 200 received from the receiving section 115 to a predetermined discharge position without handing them over to the cooling section 120. Thereafter, the preforms 200 are dropped into a discharge port by the conveying device 180, and the preforms 200 are discharged to the outside of the blow molding apparatus 100 through the discharge port.

[0048] As described above, the preform 200 after injection molding is cooled by the receiving section 115 to a temperature at which its shape can be stably maintained. Since the preform 200 is discharged to the outside while maintaining the shape obtained by injection molding, the discharged preform 200 can be stocked as an intermediate substrate from which a container can be manufactured by later blow molding. Note that if the preform 200 is high in temperature when discharged and there is a possibility that its shape or quality may be deteriorated, the injection molding conditions for the preform 200 may be changed from those during normal operation (specifically, by lengthening the cooling time in the injection molding conditions, etc.) so that the preform 200 is discharged in a sufficiently cooled state. In addition, the preform discharged outside the machine may be subjected to additional cooling, such as air cooling.

[0049] Furthermore, in the preform discharge mode, all preforms 200 injection molded in the injection molding section 110 are discharged to the outside without being transported by the conveying device 180 to the cooling section 120. Therefore, even if the blow molding apparatus 100 is operated in a state where the operating conditions of each section downstream of the conveying device 180 (such as the cooling section 120, heating section 130, continuous conveying section 150, intermittent conveying section 160, delivery section 170, and blow molding section 140) are not adjusted, by setting the operating mode to the preform discharge mode, it is possible to prevent the injection-molded preforms 200 from being discarded as defective products due to incomplete processing.

[0050] On the other hand, the preform introduction mode is an operating mode in which pre-injection molded preforms 200 can be introduced into the cooling section 120 from outside the blow molding apparatus 100. When the preform introduction mode is selected, the operation of each section upstream of the cooling section 120 is first stopped. After it is confirmed that there are no more preforms 200 being sent from the conveying device 180 to the cooling section 120, the reversing section 121 of the cooling section 120 moves to a predetermined introduction position and the safety door of the introduction port opens. In this state, the operator can introduce the pre-injection molded preforms 200 in an upright position into the cooling pod 310 provided on the first surface 121a of the reversing section 121.

[0051] The preforms 200 to be introduced may be preforms 200 that have been discharged to the outside in the preform discharge mode, or may be separately prepared preforms 200. It is preferable that the preforms 200 introduced do not vary in temperature, and it is more preferable that they have been cooled to room temperature.

[0052] After the preform 200 is introduced into the inversion section 121 through the inlet, the inversion section 121 inverts the upright preform 200 into an inverted state and delivers it to the conveying jig 152 of the continuous conveying section 150. Thereafter, the preform 200 is heated to a temperature suitable for blowing by the heating section 130, and then molded into a container in the blow molding section 140.

[0053] If it is determined in step 3 that the input operation mode switching instruction is an instruction to switch to the preform discharge mode, in step 6, the operation mode setting unit 401 controls the operation mode of the blow molding apparatus 100 to switch to the preform discharge mode, and this process is terminated.

[0054] On the other hand, if the input operation mode switching instruction in step 3 is an instruction to switch to the preform injection mode, the process proceeds to step 4. In step 4, the operation mode setting unit 401 determines whether the temperature of the heating unit 130 is within a predetermined temperature range. As described above, this predetermined temperature range is set as a temperature range that allows the preforms 200 transported through the heating unit 130 to be heated to a temperature suitable for subsequent blow molding. This predetermined temperature range may be set, for example, to 70 to 110°C, similar to the temperature range described above, or a different temperature range may be set for the preform injection mode. Since the preforms 200 introduced in the preform injection mode are expected to be sufficiently cooled, unlike the preforms 200 transported to the cooling unit 120 in the normal operation mode while still retaining the heat from injection molding, the temperature range of the heating unit 130 in the preform injection mode may be set to a temperature higher than the temperature range of the heating unit 130 in the normal operation mode.

[0055] If the determination result in step 4 is NO, meaning that the temperature of the heating section 130 is not within the predetermined temperature range, the process waits until the temperature of the heating section 130 is within the predetermined temperature range (repeating the determination in step 4). If the determination result in step 4 is YES, meaning that the temperature of the heating section 130 is within the predetermined temperature range, the process proceeds to step 7, where the operation mode setting unit 401 controls the blow molding apparatus 100 to switch to the preform injection mode, and the process ends.

[0056] Although FIG. 4 does not show the termination conditions for the preform discharge mode and the preform introduction mode, these termination conditions can be set as appropriate. For example, the interface unit 410 may be configured to allow input of an instruction to terminate each operation mode, and the operation mode setting unit 401 may switch the operation mode to the normal operation mode when the termination instruction is input. The operation mode setting unit 401 may also be configured to switch to the normal operation mode when it is confirmed that the temperature of the heating unit is within a predetermined temperature range or when it is confirmed that the external device is operating normally. Alternatively, the operation mode setting unit 401 may be configured to switch to the normal operation mode when a predetermined operation time has elapsed or when the processing of a predetermined number of preforms 200 has been completed.

[0057] The effects of this embodiment will be described below. According to this embodiment, the blow molding machine 100, which performs an integrated process from injection molding of the preform 200 to blow molding of a container, is switchable between a normal operation mode in which the injection-molded preform 200 is moved to the blow molding section 140 via the cooling section 120 and the heating section 130 to manufacture a resin container by blow molding, and a preform discharge mode in which the injection-molded preform 200 is discharged to the outside via the preform discharge section 210 without being sent to the cooling section 120.

[0058] Therefore, in a 1.5-stage blow molding apparatus, for example, when the apparatus is restarted after being stopped, the operating mode can be switched to the preform discharge mode until the operating conditions of each section, such as the cooling section 120, heating section 130, blow molding section 140, and continuous conveying section 150, are adjusted. This prevents injection-molded preforms 200 from being discarded as defective products due to incomplete processing, and allows preforms 200 in good condition that can be subjected to subsequent blow molding processing to be stored externally. Therefore, in a 1.5-stage blow molding apparatus, the amount of preforms that are injection-molded during adjustment work on the apparatus and then discarded can be reduced.

[0059] Furthermore, according to this embodiment, the blow molding apparatus 100 has an operation mode that can be switched between a preform introduction mode in which pre-injection molded preforms 200 can be introduced into the cooling section 120 from outside the blow molding apparatus 100. This allows the 1.5-stage blow molding apparatus 100 to selectively perform a molding method conforming to the 2-stage method.

[0060] Therefore, for example, a preform 200 that has been discharged outside the device in the preform discharge mode and stored can be re-introduced into the blow molding device 100 in the preform input mode and used to manufacture a resin container, so that the injection-molded preform 200 can be used effectively without being wasted.

[0061] The preform discharge mode and preform introduction mode can also be used in production tests, for example, when changing the shape of a resin container manufactured by the blow molding apparatus 100. That is, it is possible to discharge injection-molded preforms 200 to the outside in the preform discharge mode and store them, and then introduce the stored preforms 200 little by little in the preform introduction mode while adjusting each part and searching for optimal operating conditions. This makes it possible to reduce the amount of preforms discarded compared to when adjusting each part while the blow molding apparatus 100 is operating in the normal operation mode.

[0062] In addition, in this embodiment, the operation mode can be switched at any timing at the discretion of the operator because the operator is able to input an instruction to switch the operation mode via the interface unit 410. This allows the operation mode to be switched flexibly according to the operating status of the blow molding apparatus 100.

[0063] In the above embodiment, if there is an abnormality in the operating state of the blow molding apparatus 100 and an instruction to switch the operating mode is input by the operator, the operating mode is switched. However, the configuration may also be such that the apparatus is controlled to automatically switch to the preform discharge mode in situations where it is expected that a large amount of preforms 200 will be discarded if the apparatus is operated in the normal operating mode, such as when the temperature of the heating section is not within a predetermined range or when an abnormality is detected in an external device connected downstream of the blow molding apparatus 100.

[0064] For example, by switching to the preform discharge mode when the temperature of the heating section is not within a predetermined range, it is possible to prevent preforms 200 that have not yet reached the optimum blowing temperature from being blown and discarded as defective containers. Also, by switching to the preform discharge mode when an abnormality is detected in an external device connected downstream of the blow molding apparatus 100, it is possible to prevent containers manufactured by the blow molding apparatus 100 from being discarded as defective due to a malfunction in the downstream external device.

[0065] 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, the operation mode switching control is configured to switch the operation mode when an operator issues an instruction to switch the operation mode after determining an abnormality in the operating state of the blow molding apparatus based on the temperature of the heating section and the operating status of an external device. However, the operation mode may also be switched when an operator issues an instruction to switch the operation mode even if an abnormality in the operating state of the blow molding apparatus has not been determined.

[0066] In the above embodiment, the determination of an abnormality in the operating state of the blow molding apparatus is based on the temperature of the heating unit and the operating status of external devices, but the determination of an abnormality in the operating state may be based on other conditions. For example, the determination may be based on whether or not each parameter indicating the operating state of each unit, such as the cooling unit, conveying unit, or blow molding unit, is obtained and the abnormality determination is based on whether or not the parameter is a normal or appropriate value.

[0067] If the temperature condition of the heating unit 130 is not used to determine whether to switch the operation mode, the temperature detection unit 420 may be omitted. If the operation state of an external device is not used to determine whether to switch the operation mode, or if the blow molding apparatus 100 is not used in an in-line (direct-connection) production line in which the blow molding apparatus 100 is connected to an external device downstream, the operation state detection unit 430 may be omitted.

[0068] In the above embodiment, the blow molding apparatus 100 is configured to be switchable between three operating modes: a normal operating mode, a preform discharge mode, and a preform introduction mode. However, it is also possible to configure the blow molding apparatus 100 to be switchable only between the normal operating mode and the preform discharge mode, or between the normal operating mode and the preform introduction mode. In this case, the advantageous effects of the preform discharge mode or the preform introduction mode described above can be obtained. Furthermore, when operating in the preform introduction mode, if there is a possibility that the heating section 130 alone will not be able to heat the preforms 200 to a temperature suitable for blow molding, the preforms 200 may be placed in a heat-retaining device (heat-raising device) (not shown) before introduction, and the temperature at the time of introduction may be increased.

[0069] 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.

[0070] 100...blow molding apparatus, 110...injection molding section, 120...cooling section, 121...reversal section, 130...heating section, 140...blow molding section, 150...continuous conveying section, 180...conveying device, 200...preform, 210...preform discharge section, 220...preform input section, 400...control section, 401...operation mode setting section, 410...interface section, 420...temperature detection section, 430...operation state detection section

Claims

1. A blow molding apparatus comprising: an injection molding section which injection molds a resin preform; a cooling section which cools the preform, which has heat retained during injection molding, to a predetermined temperature; a heating section which continuously transports and heats the cooled preform; and a blow molding section which blow molds the heated preform to manufacture a resin container, further comprising: a preform discharge section configured to be able to discharge to the outside the preform before it is heated by the heating section; and a control section which controls the operation mode of the blow molding apparatus to be switched between a normal operation mode and a preform discharge mode, wherein in the normal operation mode, the injection-molded preform is controlled to be moved via the cooling section and the heating section to the blow molding section for blow molding, and in the preform discharge mode, the injection-molded preform is controlled to be discharged from the preform discharge section to the outside.

2. The blow molding device according to claim 1, further comprising a preform input section configured to enable the preforms that have been previously injection molded to be input into the cooling section from outside, wherein the control section executes control to switch the operating mode between the normal operating mode, the preform discharge mode, and a preform input mode, and in the preform input mode, the preforms input into the cooling section via the preform input section are controlled to be continuously transported and heated in the heating section, and then blow molded in the blow molding section.

3. A blow molding apparatus comprising: an injection molding section for injection molding a resin preform; a cooling section for cooling the preform, which has heat retained during injection molding, to a predetermined temperature; a heating section for continuously transporting and heating the cooled preform; and a blow molding section for blow molding the heated preform to manufacture a resin container, further comprising: a preform input section configured to enable the preform that has been injection molded in advance to be input from the outside to the cooling section; and a control section for controlling the operation mode of the blow molding apparatus to be switched between a normal operation mode and a preform input mode, wherein in the normal operation mode, the injection-molded preform is controlled to be moved to the blow molding section via the cooling section and the heating section and blow molding is performed, and in the preform input mode, the preform input to the cooling section via the preform input section is controlled to be continuously transported and heated by the heating section, and then blow molded in the blow molding section.

4. The blow molding device according to any one of claims 1 to 3, further comprising an interface unit configured to be able to input an instruction to switch the operation mode, and the control unit switches the operation mode in response to the input switching instruction.

5. The blow molding apparatus according to claim 1 or 2, further comprising a temperature detection unit capable of detecting the temperature of the heating unit, wherein the control unit sets the operation mode to the normal operation mode when the detected temperature is within a predetermined temperature range, and sets the operation mode to the preform discharge mode when the detected temperature is not within the predetermined temperature range.

6. A blow molding apparatus as described in claim 1 or 2, further comprising an operating status detection unit capable of detecting the operating status of an external device connected to the blow molding apparatus downstream of the blow molding apparatus, wherein the control unit sets the operating mode to the preform discharge mode when the detected operating status indicates an abnormality in the external device.

7. A control method for a blow molding apparatus comprising: an injection molding section which injection molds a resin preform; a cooling section which cools the preform, which has heat retained during injection molding, to a predetermined temperature; a heating section which continuously transports and heats the cooled preform; and a blow molding section which blow molds the heated preform to manufacture a resin container, characterized in that the control method controls to switch the operation mode of the blow molding apparatus between a normal operation mode and a preform discharge mode, in which, in the normal operation mode, the injection-molded preform is controlled to be moved via the cooling section and the heating section to the blow molding section for blow molding, and in the preform discharge mode, the injection-molded preform is controlled to be discharged from the preform discharge section to the outside before being heated by the heating section.

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