JP2012101805A - Heat sealing device and heat sealing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat sealing device capable of responding even to a packaging machine operating at high speed and a packaging machine operating at variable speed.SOLUTION: The heat sealing device 1 includes an upper seal member 10 and a lower seal member 20 having heating elements 12, 22 installed therein, respectively, and an opening of a packaging bag containing a product is sandwiched between the upper seal member 10 and the lower seal member 20 and sealed by heat seal. The heat sealing device 1 further includes: temperature sensors 15, 25 measuring temperatures of the heating elements; and a controller 30 having a memory storing a voltage setting table in which an application voltage to the heating elements 12, 22 with respect to each temperature of the heating elements 12, 22 is preset to achieve successful sealing and performing control to apply a voltage corresponding to the measurement temperatures by the temperature sensors 15, 25 at the start of voltage application to the heating elements 12, 22 by referring to the voltage setting table when voltages are applied to the heating elements 12, 22.

Description

  The present invention relates to a sealing device for closing a mouth of a packaging bag containing a product by heat fusion, and more particularly to an impulse heat fusion device.

  Regarding packaging machines for packaging products, many packaging machines are provided with a sealing device for closing the mouth of the packaging bag containing the products by heat sealing (heat sealing). 1-6.

  As a sealing device, an impulse-type heat fusion device that performs heat fusion by applying a pulse current to a heating element (nichrome wire) has been proposed as being capable of relatively quick temperature control. To 5 are disclosed. Patent Documents 1 to 5 below disclose that the seal temperature is controlled based on the temperature measured by a sensor or the like.

JP-A-6-247424 Japanese Patent Laid-Open No. 11-35014 JP 2002-166904 A JP 2002-193217 A JP 2005-96829 A JP 2009-90984 A

  By the way, in recent years, the speed of packaging machines has been remarkably increased, and packaging machines that seal several dozen or more shot bags per minute, that is, dozens or more of packaging bags per minute, have appeared. Further, as disclosed in the above-mentioned Patent Document 6, with the increase in the number of shots, if an intermittent operation for temporarily stopping the operation of the packaging machine that operates at high speed is performed, the burden on the packaging machine is greatly damaged. As a result, packaging machines that can operate non-stop while adjusting the speed have also appeared.

  Here, in the sealing devices disclosed in Patent Documents 1 to 5, based on the measured temperature or the like, temperature control that feedback-controls the time and magnitude of voltage application so that the heating element becomes a constant temperature. Has been done. However, the conventional feedback temperature control is difficult to cope with a packaging machine that operates at a high speed or a packaging machine that changes its operation speed, and a sealing failure occurs.

  This invention is made in view of such a subject, and it aims at providing the heat-fusion method and heat-fusion apparatus which can respond also to the packaging machine which operates at high speed, and the packaging machine of variable speed. .

  In order to solve the above-described problems, a heat fusion method according to the present invention includes a heat fusion method in which a mouth of a packaging bag in which a product is placed is sandwiched between an upper seal member and a lower seal member and sealed by heat fusion. In the heat-sealing method in an impulse-type heat-sealing device provided with a temperature sensor for measuring the temperature of the heat-generating body installed on the sealing member, the temperature of the heat-generating body so that the sealing is performed satisfactorily A voltage applied to the heating element for each heating element is set in advance, and when the voltage is applied to the heating element, a voltage corresponding to the measured temperature of the temperature sensor at the start of voltage application with reference to the setting is set to the heating element. It is characterized by applying to.

  The heat sealing apparatus according to the present invention further includes an upper seal member and a lower seal member each having a heating element installed on at least one side thereof, and a mouth of a packaging bag in which a product is placed is connected to the upper seal member and the lower seal member. In a heat-sealing device that is sandwiched between side-sealing members and sealed by heat-sealing, a temperature sensor that measures the temperature of the heating element, and the heat generation for each temperature of the heating element so that sealing is performed satisfactorily A controller having a memory for storing a voltage setting table in which an applied voltage to the body is set in advance, and when applying a voltage to the heating element, refer to the voltage setting table and the temperature at the start of voltage application And a controller for controlling to apply a voltage corresponding to the measured temperature of the sensor to the heating element.

  According to the heat fusion method and the heat fusion apparatus according to the present invention, it is possible to perform a good heat seal in correspondence with a packaging machine that operates at a high speed or a packaging machine with a variable speed.

FIG. 1 is a front view of a heat fusion apparatus according to an embodiment. FIG. 2 is an enlarged top perspective view showing an installation portion of the temperature sensor of the heat fusion apparatus according to the embodiment. Drawing 3 is a mimetic diagram for explaining the installation position of the heat fusion equipment concerning an embodiment. FIG. 4 is a diagram for explaining a temperature change due to voltage application to the heating element according to the embodiment. FIG. 5 is a diagram illustrating a setting example of a voltage setting table according to the embodiment. FIG. 6 is a diagram illustrating a setting example of the timing setting table according to the embodiment.

  Hereinafter, a heat fusion apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front view of the heat sealing apparatus according to the present embodiment. FIG. 2 is an enlarged top perspective view showing an installation portion of the temperature sensor of the heat fusion apparatus according to the present embodiment. FIG. 3 is a schematic diagram for explaining the installation position of the heat fusion apparatus according to the present embodiment.

  In the present embodiment, an impulse that heat seals and seals the entrance of a packaging bag in which a predetermined number of products (paper diapers, sanitary napkins, pet sheets, etc.) manufactured by a manufacturing machine and counted by a counter are placed. A heat sealing apparatus of the type, which is installed in a high speed and variable speed packaging machine, will be described.

  As shown in FIG. 1, the heat sealing apparatus 1 includes an upper seal member 10, a lower seal member 20, and a controller 30. The heat fusion apparatus 1 is installed on the conveyance path through which the packaging bag containing the product passes in the packaging machine, and as shown in FIG. 3, the upper seal member 10 is installed above the conveyance path 5. A lower seal member 20 is installed below the conveyance path 5.

  Further, the lower seal member 20 is installed in the vicinity of the conveyance path 5 (downward by about 5 mm), whereas the upper seal member 10 is installed in a place away from the conveyance path 5. Then, when the entrance of the packaging bag is conveyed to the heat fusion apparatus 1, the upper seal member 10 and the lower seal member 20 are driven to move down and ascend to the position of the conveyance path 5 by driving a drive member (not shown). Then, the opening of the packaging bag is sandwiched between the upper and lower sealing members 10 and 20 and heat-sealed.

  The upper seal member 10 measures the temperature of the upper seal body 11, the upper heating element 12 made of a strip-shaped nichrome wire installed on the lower surface of the upper seal body 11 in the left and right directions in the figure, and the upper heating element 12. A bar-shaped upper temperature sensor 15 made of a thermocouple is provided.

  The lower seal member 20 includes a lower seal body 21, a lower heating element 22 made of a strip-shaped nichrome wire installed on the upper surface of the lower seal body 21 in the left and right directions in the drawing, and a lower heating element 22. A bar-shaped lower temperature sensor 25 made of a thermocouple for measuring the temperature of is provided.

  The controller 30 is connected to both ends of the heating elements 12 and 22 by wiring 31 and is connected to the upper temperature sensor 15 and the lower temperature sensor 25 by wiring 33. The controller 30 controls the heating elements 12 and 22 to generate heat by applying a voltage by applying a pulse current to the upper heating element 12 and the lower heating element 22.

  Note that the controller 30 applies a predetermined voltage (for example, 2 to the heating elements 12 and 22 so as to keep the heating elements 12 and 22 at a predetermined standby temperature (60 ° C. in the present embodiment) during standbys other than sealing. It is controlled to apply a voltage of ~ 3V).

  Next, the installation state of the lower temperature sensor 25 will be described with reference to FIG. The rod-shaped temperature sensor 25 is fixed to the lower seal body 21 so as to pass through two holes provided on both side surfaces of the lower seal body 21 and to be orthogonal to the extending direction of the belt-like heating element 22. .

  In addition, a recess is provided at a location where the lower temperature sensor 25 of the lower seal body 21 is installed, and the belt-like heating element 22 goes around the lower side of the temperature sensor 25 by falling into this recess, and the temperature The sensor 25 is in contact from below.

  In addition, the contact position between the heating element 22 and the temperature sensor 25 is 10 mm away from the tip of the temperature sensor 25, and it is possible to perform reliable temperature measurement with a larger contact area than when measured at the tip. It has become. The installation state of the upper temperature sensor 15 is the same as that of the lower temperature sensor 25 described above although it is upside down.

  Here, the packaging machine in which the heat fusion apparatus 1 according to the present embodiment is installed is a packaging machine that employs a servo mechanism controlled by a virtual control system and has a variable number of shots per unit time. In the virtual control system, the control systems of a plurality of servo mechanisms that are synchronously driven at a predetermined cycle are connected to the same virtual axis, and each servo mechanism is controlled by an angle, and the thermal fusion apparatus 1 is also connected to this virtual axis. It is driven by a connected servo mechanism.

  The configuration of the heat fusion apparatus 1 has been described above. Next, voltage application control to the heating elements 12 and 22 by the controller 30 will be described. In this embodiment, first, the magnitude of the applied voltage is determined based on the measured temperature of the temperature sensors 15 and 25 at the start of voltage application so that the packaging machine can be increased in speed and change in speed (change in the number of shots). Control is a major feature.

  First, a temperature change of a general heating element (nichrome wire) during voltage application will be described with reference to FIG. FIG. 4 shows temperature changes due to voltage application to the heating element, with the horizontal axis representing time and the vertical axis representing the temperature of the heating element. FIG. 4A shows a temperature change due to voltage application to the heating element during low-speed conveyance, and FIG. 4B shows a temperature change due to voltage application to the heating element during high-speed conveyance.

  Conventionally, by applying a constant voltage for a predetermined time each time the packaging bag is conveyed, the temperature of the heating element is instantaneously increased to a predetermined sealing temperature (about 180 ° C. in this embodiment) to perform sealing. The temperature of the heating element was changed as shown in FIG. However, due to an increase in the speed of the packaging machine, there is a case where after the voltage application is completed (OFF), the next voltage application is performed before the temperature of the heated heating element returns to the standby temperature by natural cooling. .

  Then, if the same voltage as before is applied for the same predetermined time, the temperature of the heating element gradually rises and greatly exceeds the predetermined seal temperature as shown in FIG. It becomes.

  Therefore, in this embodiment, the magnitude of the voltage to be applied is set in advance according to the temperature of the heating elements 12 and 22 at the start of voltage application (ON), and the heating elements 12 and 22 at the start of voltage application are preset. Based on the measured temperature, the controller 30 controls to apply a predetermined voltage so that an appropriate seal temperature can be obtained.

  FIG. 5 shows a setting example of a voltage setting table in which the magnitude of the voltage applied to the heating elements 12 and 22 is preset according to the temperature of the heating elements 12 and 22. 5A shows setting example 1 of the voltage setting table, and FIG. 5B shows setting example 2 of the voltage setting table. The voltage setting table may be set manually by performing a test or the like in advance for each type of packaging bag. Setting example 1 shows a setting example for type 1 and setting example 2 shows a setting example for type 2. ing.

  This voltage setting table is recorded in a memory in the controller 30, and the controller 30 applies voltage to the heating elements 12 and 22 while referring to this voltage setting table when the heat fusion apparatus 1 is operated. Control. In the voltage setting table, the applied voltage value is set separately for the upper seal member 10 and the lower seal member 20, and the controller 30 is independent based on the measured temperatures of the temperature sensors 15 and 25. The voltage application to the heating elements 12 and 22 is controlled.

  For example, as shown in FIG. 5, in the voltage setting table according to the present embodiment, the applied voltage is set in 19 steps according to the measured temperature at the start of voltage application. In setting example 1, when the measured temperature is 145 ° C. or higher and the temperatures of the heating elements 12 and 22 are not yet lowered, the upper seal member 10 has a voltage of 9V, and the lower seal member 20 has a voltage of 8V. It is set to apply.

  When the measured temperature is 100 ° C. or more and less than 105 ° C. and the temperatures of the heating elements 12 and 22 are slightly lowered, a voltage of 12V is applied to the upper seal member 10 and 11.5V is applied to the lower seal member 20. It is set to apply. When the measured temperature is less than 60 ° C. and the temperatures of the heating elements 12 and 22 are sufficiently lowered to the standby temperature, a voltage of 15 V is applied to both the upper seal member 10 and the lower seal member 20. Is set.

  Thus, as the measured temperature of the heating elements 12 and 22 at the start of voltage application becomes higher than the standby temperature (60 ° C. in this embodiment), a voltage gradually lower than the applied voltage (15 V) at the standby temperature is applied. By controlling so that the heating element is always applied to the desired seal temperature (about 180 ° C. in the present embodiment), even when the next voltage is applied in any temperature state from the immediately preceding applied voltage OFF. 12 and 22 can be heated.

  In addition, by determining the applied voltage based on the voltage setting table in this way, the applied voltage can be determined instantaneously based on the measured temperature at the start of voltage application, and it is sufficient to handle even when operating at high speed. Can do.

  In the voltage setting table, there is a place where the applied voltage to the upper heating element 12 is set slightly higher than the applied voltage to the lower heating element 22 even at the same measurement temperature. This is because, even during standby, the lower seal member 20 is installed in the vicinity of the transport path 5 of the packaging bag to prevent the product from being burnt.

  Next, the thermal fusion bonding apparatus 1 according to the present embodiment sets the voltage application timing according to the number of shots per unit time so that the packaging machine can cope with higher speed and speed change (change in the number of shots). Control is a major feature.

  As described above, the packaging machine in which the thermal fusion apparatus 1 according to the present embodiment is installed controls each servo mechanism according to the angle. Therefore, when the number of shots of the packaging machine changes, the period of the servo mechanism changes and the upper side The drive cycle of the drive member that lowers and raises the seal member 10 and the lower seal member 20 also changes.

  And the heat sealing | fusion apparatus 1 which concerns on this embodiment descend | falls and raises the upper side sealing member 10 and the lower side sealing member 20 to the location of the conveyance path 5 between 45-180 degrees, and the upper side sealing member 10 and The lower sealing member 20 is configured to sandwich the packaging bag and perform heat sealing. That is, in this embodiment, the angle at which the seal members 10 and 20 are in contact with the packaging bag is constant at 45 to 180 °.

  For this reason, when the speed of a packaging machine changes and the period of a virtual control system changes, the time for the sealing members 10 and 20 to contact and fuse with the packaging bag also changes. For example, if the number of shots per minute is 20 (shot / min), one rotation (one cycle) of the control system is 3 seconds and the contact time is 1.125 seconds (135 °), but the number of shots is 40 At (shot / min), one rotation is 1.5 seconds, and the contact time is 0.5625 seconds (135 °).

  On the other hand, as shown in FIG. 4, the heating elements 12 and 22 take a certain time from the application of voltage until the temperature rises. Therefore, when the number of shots is large and the contact time between the seal members 10 and 20 and the packaging bag is short, the contact is made before the temperature of the heating elements 12 and 22 rises to the seal temperature when the voltage is applied at the start of contact. May end and a sealing failure may occur due to insufficient heating.

  Therefore, in the present embodiment, the time for applying the voltage at the time of applying each voltage (voltage application time) is set to a fixed time, and the timing for starting the voltage application is controlled in accordance with the change in the number of shots. Therefore, heat sealing can be performed with an appropriate heating amount regardless of the contact time. The voltage application time is also set to a fixed time (for example, 1 second) for each type of packaging bag, and is separately recorded in the memory in the controller 30.

  An example of a timing setting table in which the voltage application start timing according to the number of shots per unit time is set in advance is shown in FIG. The timing setting table may be set manually by performing a test in advance for each shot number.

  The timing setting table is recorded in a memory in the controller 30. When the heat sealing apparatus 1 is operated, the controller 30 refers to the timing setting table while referring to the timing setting table. The timing for starting voltage application to the heating elements 12 and 22 is controlled in accordance with the number of shots.

  For example, as shown in FIG. 6, in the timing setting table according to the present embodiment, the voltage application start timing is set in six stages according to the number of shots per unit time, and each timing is set by an angle.

  In this timing setting table, when the number of shots is less than 20, the voltage application start timing is set to 45 °, that is, the same as the angle at which the sealing members 10 and 20 and the packaging bag start to contact, When the number is 20 or more and less than 25, the voltage application start timing is set slightly forward to 40 °, and when the number of shots is 40 or more, the voltage application start timing is set to advance 20 °.

  That is, based on this setting table, as the number of shots increases and the contact time between the seal members 10 and 20 and the packaging bag decreases, the contact time is controlled by shifting the voltage application start timing forward. Even if the length is shortened, a good seal with an appropriate heating amount can be realized.

  Although the present embodiment has been described in detail above, according to the present embodiment, the magnitude of the voltage to be applied is set in advance according to the temperature of the heating elements 12 and 22 at the start of voltage application, and the voltage application The controller 30 controls to apply a predetermined voltage based on the measured temperature of the heating elements 12 and 22 at the start, so that an appropriate seal temperature can be obtained even in a high-speed packaging machine or a variable speed packaging machine. A good seal can be realized.

  Further, according to the present embodiment, the timing for starting the voltage application is set in advance in accordance with the change in the number of shots, and the voltage application is started at a timing determined in advance according to the number of shots at the time of starting the voltage application By controlling the controller 30 to do so, sealing with an appropriate heating amount can be performed regardless of the length of the contact time.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention are not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention. For example, it goes without saying that various set values such as the temperature, voltage, time, and angle described above can be changed as appropriate.

  In the above embodiment, the heating element and the temperature sensor are respectively installed on the upper and lower sealing members, and the case where the voltage application to each heating element is controlled independently in the upper and lower directions has been described. However, the temperature sensor is installed only on one side. The voltage application to the two heating elements installed on the upper and lower seal members may be collectively controlled based on the measured value of the temperature sensor. Further, the heating element and the temperature sensor may be installed only on one of the upper and lower seal members.

DESCRIPTION OF SYMBOLS 1 Heat-fusion apparatus 10 Upper seal member 11,21 Seal main body 12,22 Heat generating body 15,25 Temperature sensor 20 Lower seal member 30 Controller

Claims (5)

A heat-sealing device that seals the mouth of a packaging bag containing a product between an upper seal member and a lower seal member by heat fusion, and measures the temperature of a heating element installed on the seal member In a heat fusion method in an impulse heat fusion apparatus including a temperature sensor to perform,
The voltage applied to the heating element for each temperature of the heating element is set in advance so that the sealing is performed satisfactorily. A heat fusion method, wherein a voltage corresponding to a temperature measured by a temperature sensor is applied to the heating element. An upper seal member and a lower seal member each having a heating element installed on at least one of them, and heat-sealed by sandwiching a mouth of the packaging bag containing the product between the upper seal member and the lower seal member In the impulse-type heat-sealing device that seals with
A temperature sensor for measuring the temperature of the heating element;
A controller having a memory for storing a voltage setting table in which a voltage applied to the heating element for each temperature of the heating element is set in advance so that sealing is performed satisfactorily, the voltage application to the heating element And a controller for controlling to apply a voltage corresponding to the temperature measured by the temperature sensor at the start of voltage application to the heating element with reference to the voltage setting table. apparatus. The heat fusion apparatus is a heat fusion apparatus installed in a packaging machine using a servo mechanism in which the number of shots per unit time is variable,
The memory of the controller stores a timing setting table in which the voltage application start timing to the heating element for each number of shots is set in advance so that sealing is performed satisfactorily.
The controller controls to start voltage application to the heating element at a timing corresponding to the number of shots per unit time of the packaging machine with reference to the timing setting table at the start of voltage application to the heating element. The heat sealing apparatus according to claim 2, wherein:   4. The heat fusion apparatus according to claim 3, wherein a voltage application time for applying a voltage when each voltage is applied to the heating element is set to be constant. The upper seal member and the lower seal member each include the heating element and the temperature sensor,
5. The heat fusion apparatus according to claim 2, wherein the controller performs voltage application control to the heating element independently by the upper seal member and the lower seal member. 6. .

Images