Ultrasonic sealing device and control method for ultrasonic sealing device

Abstract

To provide an ultrasonic sealing device capable of realizing energy saving and preventing seal failure, and a control method of the ultrasonic sealing device.SOLUTION: A control part 13 provided in an ultrasonic sealing device 10 obtains, based on a main frequency signal output by a vibration sensor 50 that detects a main vibration frequency of an ultrasonic resonator 18, applied heat applied by the ultrasonic resonator to a horn 15 and surplus heat other than the welding heat consumed in the welding of a packaging bag B, and obtains an insufficient energy to be insufficient in the next welding process from a difference between the applied heat and the surplus heat. In addition, the stored energy related to the heat storage of the horn or an anvil 16 is obtained by excluding the heat radiation from the surplus heat, and a vibration control signal related to a sub vibration energy obtained by subtracting the stored energy carried over from the preceding and following sealing process from the insufficient energy is output to a vibration part unit 14, and a position control signal is output to an actuator based on an environmental temperature pertaining to the horn or the anvil based on the heat storage.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic sealing device and a control method for the ultrasonic sealing device. [Background technology]

[0002] In an ultrasonic sealing device, a heat-sealable film is sandwiched between a horn that generates ultrasonic vibrations and an anvil that receives the ultrasonic vibrations, and the film is welded by frictional heat generated by the ultrasonic vibrations. Conventionally, the horn or anvil maintains constant the sealing conditions of the ultrasonic sealing device, such as the energy of the ultrasonic vibrations applied to the horn, the amplitude and frequency of the ultrasonic vibrations, and the pressure with which the horn is pressed against the anvil, to prevent excessive melting of the film, which can occur when the horn or anvil is overheated by the frictional heat described above, or poor sealing caused by thermal expansion of the horn or anvil. However, the temperature of the entire ultrasonic sealing device, including the horn and anvil, gradually rises due to frictional heat generated by the vibration energy associated with the ultrasonic vibrations applied to the horn. If the above sealing conditions are set based on the steady state in which the ultrasonic sealing device has reached thermal equilibrium, i.e., the time when the frictional heat generated by the energy applied to the horn is equal to the amount of heat dissipated by natural heat dissipation or cooling by a cooling device, etc., poor sealing may occur due to insufficient melting or pressure during the transitional period from the start of the ultrasonic sealing device to the steady state. On the other hand, if the conditions are set based on the time immediately after start of the ultrasonic sealing device, the temperature of the ultrasonic sealing device, horn, and anvil may rise during multiple sealing operations, resulting in poor sealing due to excessive melting.

[0003] To address the above-mentioned problems, the ultrasonic film sealing device disclosed in JP 2017-47917 A is configured to ultrasonically seal the film along the film feed direction while cooling the horn, similar to conventional technology. Furthermore, the control unit issues operational commands to vibrate the horn and to the cooling means based on operation signals from the operation unit, and is configured to have a warm-up operation mode in which, after a set period of time has elapsed for each operational command, information is obtained regarding the stability of the thermal expansion change of the horn and information is output that allows the device to transition to packaging operation. This allows the ultrasonic film sealing device to stabilize the thermal expansion changes of the horn, which generates heat due to ultrasonic vibrations, while ultrasonically sealing the film with a stable, appropriate sealing pressure along the film feed direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-47917 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional ultrasonic sealing device and ultrasonic film sealing device described above control the vibration energy of the ultrasonic vibrations applied to the horn to a constant level so as to meet the specified sealing conditions. The ultrasonic film sealing device is configured to warm up the horn for a predetermined period of time and then start ultrasonic sealing once the thermal expansion change has stabilized. In this way, when warm-up operation and cooling means are combined, the vibration energy applied to the horn is wasted as heat in addition to frictional heat, as a result of which energy efficiency is poor and the ultrasonic sealing device may consume a lot of power. Furthermore, if the packaging machine is operating during or immediately after warm-up, the applied vibration energy and the resulting frictional heat may not be stable, which may result in poorly sealed bag products.

[0006] Therefore, the problem that the present invention aims to solve is to provide an ultrasonic sealing device that can achieve energy savings and prevent poor sealing, and a control method for the ultrasonic sealing device. [Means for solving the problem]

[0007] The ultrasonic sealing device according to claim 1 comprises: a horn having a pressing surface that transmits predetermined ultrasonic vibrations; an anvil having a receiving surface disposed opposite the pressing surface of the horn; a vibration unit having an ultrasonic oscillator that oscillates the ultrasonic vibration at a predetermined vibration frequency and an output shaft that outputs the ultrasonic vibration from the ultrasonic oscillator, the horn being connected to a tip of the output shaft; an actuator that holds the vibration unit so as to be freely movable toward and away from the anvil, and presses the pressing surface toward the receiving surface with a predetermined pressure when the horn connected to the vibration unit is brought close to the anvil; a vibration sensor that detects the vibration frequency of the ultrasonic oscillator; a control unit that controls the operation of both or either one of the vibration unit and the actuator based on the vibration frequency detected by the vibration sensor, A seal protrusion is formed at a predetermined position on either the pressing surface or the receiving surface, the top of which presses against a pressure-contact portion of a sealed body, and A slot is formed at a predetermined position on one of the pressing surface and the receiving surface, into which the clamped portion of the object to be sealed is pressed, and a clamping protrusion is formed on the other surface, which presses the clamped portion into the slot to clamp the object to be sealed, When the actuator moves the horn connected to the vibration unit toward the anvil, the clamped portion is clamped between the slot and the clamping ridge to fix the sealed object between the pressing surface and the receiving surface, and the pressing surface is pressed toward the receiving surface, and at the same time, the ultrasonic oscillator oscillates with a predetermined main ultrasonic vibration, and main vibration energy related to the main ultrasonic vibration is applied to the horn, an ultrasonic sealing device in which the pressure-welded portion pressed by the sealing ridge is welded at a predetermined sealing temperature by frictional heat associated with the main vibration energy, and the sealing ridge sinks a predetermined amount into the pressure-welded portion melted by the frictional heat, thereby linearly sealing the pressure-welded portion along the sealing ridge, When the vibration sensor detects a main vibration frequency of the main ultrasonic vibration and outputs a main frequency signal based on the main vibration frequency to the control unit, the control unit determines a total amount of applied heat from the input start time of the main frequency signal to a predetermined detection time with respect to the applied heat based on the main vibration energy, and determines a total amount of excess heat from the input start time to the detection time with respect to excess heat obtained by subtracting the welding heat consumed in the work related to the previous welding between the sealing ridge and the pressing surface from the frictional heat, and calculates an energy deficiency that is insufficient for the work related to the subsequent welding at the detection time by subtracting the total amount of excess heat from the total amount of applied heat; calculating an environmental temperature in the vicinity of the horn and the anvil based on the accumulated heat in the horn and the anvil at the detection time by subtracting a predetermined amount of heat radiation from the excess heat; a vibration control signal relating to the subordinate ultrasonic vibration is output to the vibration unit in order to compensate for the energy obtained by subtracting the stored energy relating to the heat storage from the deficient energy with the subordinate ultrasonic vibration output from the ultrasonic oscillator; outputting a position control signal to the actuator to move the horn having the pressing surface toward and away from a predetermined position relative to the pressure-welded portion that is melted by secondary vibration energy related to the secondary ultrasonic vibration and the environmental temperature; the actuator controls the position of the vibration unit based on the position control signal to adjust the amount of depression of the sealing protrusion with respect to the pressure-welded portion; The vibration unit is The ultrasonic oscillator is oscillated to output the secondary ultrasonic vibration, In response to the rise and fall of the environmental temperature, the ultrasonic oscillator adjusts the secondary vibration energy that it applies to the pressure-welded portion by the secondary ultrasonic vibration, and the actuator adjusts the position of the vibration unit so that the amount of sinking of the sealing protrusion into the pressure-welded portion, which melts due to the secondary vibration energy and the environmental temperature, is kept constant within a predetermined range, thereby sealing the pressure-welded portion.

[0008] The ultrasonic sealing device according to claim 2 is characterized in that, in the invention according to claim 1, the sinking amount is 10 μm to 200 μm.

[0009] The ultrasonic sealing device according to claim 3 is the invention according to claim 2, characterized in that when the pressure-welded portion is made of a synthetic resin material for retort pouches, the sinking amount is 60 μm to 75 μm.

[0010] The ultrasonic sealing device according to claim 4 is the invention according to claim 1, characterized in that the energy deficiency at the predetermined detection time is substantially constant from the input start time.

[0011] The ultrasonic sealing device according to claim 5 is the invention according to claim 1, characterized in that the object to be sealed is a packaging bag having a predetermined heat-sealable film at least on the opening of the bag.

[0012] The ultrasonic sealing device described in claim 6 is the invention described in claim 1, characterized in that the object to be sealed is a packaging container that can be covered by welding a predetermined heat-sealable film to the peripheral edge of the container.

[0013] The method for controlling an ultrasonic sealing device according to claim 7 includes the steps of: an anvil having a receiving surface disposed opposite the pressing surface of the horn; a vibration unit having an ultrasonic oscillator that oscillates the ultrasonic vibration at a predetermined vibration frequency and an output shaft that outputs the ultrasonic vibration from the ultrasonic oscillator, the horn being connected to a tip of the output shaft; an actuator that holds the vibration unit so as to be freely movable toward and away from the anvil, and presses the pressing surface toward the receiving surface with a predetermined pressure when the horn connected to the vibration unit is brought close to the anvil; a vibration sensor that detects the vibration frequency of the ultrasonic oscillator; a control unit that controls the operation of both or either one of the vibration unit and the actuator based on the vibration frequency detected by the vibration sensor, A seal protrusion is formed at a predetermined position on either the pressing surface or the receiving surface, the top of which presses against a pressure-contact portion of a sealed body, and In an ultrasonic sealing device, a slot into which a clamped portion of the object to be sealed is pressed is formed at a predetermined position on one of the pressing surface and the receiving surface, and a clamping protrusion is formed on the other surface to clamp the object to be sealed by pressing the clamped portion into the slot, a pressing step in which the actuator moves the horn connected to the vibration unit toward the anvil, clamping the clamped portion between the slot and the clamping ridge to fix the sealed object between the pressing surface and the receiving surface, and pressing the pressing surface toward the receiving surface to press the pressure-welded portion between the sealing ridge and the pressing surface; When the ultrasonic oscillator oscillates with a predetermined main ultrasonic vibration and the main vibration energy related to the main ultrasonic vibration is applied to the horn, a control method for an ultrasonic sealing device including a welding process in which the horn performs a process of welding the pressure-welded portion, which is pressure-welded by the sealing protrusion, at a predetermined sealing temperature by frictional heat associated with the primary vibration energy, a vibration frequency output process in which the vibration sensor detects a main vibration frequency associated with the main ultrasonic vibration and outputs a main frequency signal based on the main vibration frequency to the control unit; a total applied heat amount calculation step in which the control unit performs processing to calculate a total applied heat amount from an input start time of the main frequency signal to a predetermined detection time, with respect to the applied heat based on the main vibration energy; a total excess heat calculation step in which the control unit performs processing to calculate a total excess heat amount from the input start time to the detection time, with respect to excess heat obtained by subtracting welding heat consumed in work related to previous welding between the sealing ridge and the pressing surface from the frictional heat during the welding step between the horn and the anvil; a deficit energy calculation step in which the control unit calculates a deficit energy required for subsequent welding work at the detection time by subtracting the total surplus heat amount from the total applied heat amount, In parallel with both or either one of the pressure welding step and the welding step, an environmental temperature calculation step in which the control unit calculates an environmental temperature in the vicinity of the horn and the anvil based on the accumulated heat stored in the horn and the anvil at the detection time by subtracting a predetermined amount of heat radiation from the excess heat; a vibration control step in which the control unit outputs a vibration control signal relating to the subordinate ultrasonic vibration to the vibration unit unit in order to compensate for the energy obtained by subtracting the accumulated energy relating to the heat storage from the energy deficiency with the subordinate ultrasonic vibration output from the ultrasonic oscillator; a position control step in which the control unit outputs a position control signal to the actuator to move the horn having the pressing surface toward and away from a predetermined position relative to the pressure-welded portion that is melted by secondary vibration energy related to the secondary ultrasonic vibration and the environmental temperature, a pressing control process is provided in which the actuator controls the position of the vibration unit based on the position control signal to adjust the amount of depression of the sealing protrusion into the pressure-welded portion, in relation to the pressing process; In the welding process, the vibration unit The ultrasonic oscillatora welding control step of oscillating the ultrasonic vibration and outputting the ultrasonic vibration, In response to the rise and fall of the environmental temperature, the ultrasonic oscillator adjusts the secondary vibration energy that it applies to the pressure-welded portion by the secondary ultrasonic vibration, and the actuator adjusts the position of the vibration unit so that the amount of sinking of the sealing protrusion into the pressure-welded portion, which melts due to the secondary vibration energy and the environmental temperature, is kept constant within a predetermined range, thereby sealing the pressure-welded portion.

[0014] The method for controlling an ultrasonic sealing device according to claim 8 is characterized in that, in the invention according to claim 7, the sinking amount is 10 μm to 200 μm.

[0015] The control method for an ultrasonic sealing device described in claim 9 is characterized in that, in the invention described in claim 8, when the pressure-welded portion is made of a synthetic resin material for retort pouches, the sinking amount is 60 μm to 75 μm.

[0016] The control method for an ultrasonic sealing device according to claim 10 is characterized in that, in the invention according to claim 7, the energy deficiency at the predetermined detection time is substantially constant from the input start time.

[0017] The control method of an ultrasonic sealing device described in claim 11 is characterized in that, in the invention described in claim 7, the object to be sealed is a packaging bag provided with a predetermined heat-sealable film at least on the bag opening.

[0018] The control method for an ultrasonic sealing device described in claim 12 is characterized in that, in the invention described in claim 7, the object to be sealed is a packaging container that can be covered by welding a predetermined heat-sealable film to the peripheral edge of the container. [Effects of the Invention]

[0019] In the ultrasonic sealing device according to the present invention, a vibration sensor detects the main vibration frequency of the main ultrasonic vibrations generated by the ultrasonic oscillator of the vibration unit and outputs a main frequency signal based on the main vibration frequency to a control unit. The control unit then controls the vibration energy of the ultrasonic vibrations applied to the horn via the output shaft by the ultrasonic oscillator based on the main frequency signal. Specifically, the total applied heat amount related to the applied energy applied by the ultrasonic vibrations from the start time of input of the main frequency signal to a predetermined detection time is calculated, and the total excess heat amount from the start time of input of the main frequency signal to the detection time is calculated for the excess heat obtained by subtracting the welding heat consumed for the work related to the previous welding from the frictional heat applied by the horn. The heat amount obtained by subtracting the total excess heat amount from the total applied heat amount is the energy shortage for the work related to the subsequent welding at the detection time. In other words, the ultrasonic oscillator can fully perform the subsequent welding work by applying ultrasonic vibrations at most to compensate for the energy deficiency. Therefore, instead of constantly applying a constant vibration energy from the start of input of ultrasonic vibrations, the ultrasonic oscillator carries over the surplus heat not consumed in the previous welding work based on the fed-back main vibration energy of the main ultrasonic vibration to determine the energy deficiency, and by applying new secondary vibration energy of the secondary ultrasonic vibration to compensate for the energy deficiency, the welding heat consumed in the subsequent welding work can be met, thereby realizing energy conservation in the ultrasonic sealing device. Furthermore, the excess heat is composed of heat dissipated from the horn or anvil by a cooling device, natural cooling, etc., and heat stored in the horn and anvil. The ultrasonic sealing device of the present invention focuses on the heat storage and calculates the ambient temperature in the vicinity of the horn or anvil based on the heat stored in the horn or anvil at the time of detection. Subtracting the stored energy related to the heat storage from the energy deficit means that the stored energy related to the heat storage, excluding the heat dissipation from the total excess heat, is carried over to the welding in the next sealing process. This allows the carried-over stored energy to be reduced from the secondary vibration energy, which corresponds to the energy deficit, thereby achieving further energy savings in the ultrasonic sealing device. In this way, the ultrasonic sealing device according to the present invention is configured so that the vibration control signal output from the control unit feeds back the primary ultrasonic vibrations previously output by the ultrasonic oscillator, and the surplus heat, minus the heat consumed in the previous welding job, accumulated in the horn and anvil is carried over to the next welding job to compensate for the lack of welding heat in the next welding job, and any energy that is still insufficient even after the heat is compensated for is made up with the secondary vibration energy of the secondary ultrasonic vibrations output later by the ultrasonic oscillator. This allows sufficient welding to be achieved by making up for the minimum necessary energy deficiency, thereby realizing energy savings in the ultrasonic sealing device. The control unit outputs a position control signal to the actuator to move the horn connected to the vibration unit toward or away from a predetermined position based on the compensated secondary vibration energy and the ambient temperature related to the carried-over heat storage. This allows the actuator to maintain a substantially constant amount of depression of the seal ridge pressed during welding within a predetermined range, even if the pressure-welded portion melts or its hardness changes due to the temperature based on the applied or carried-over energy. As a result, the amount of depression of the seal ridge can be optimized for the pressure-welded portion, whose hardness changes depending on the ambient temperature. Therefore, with the ultrasonic sealing device of the present invention, the shortage of welding heat consumed in the next welding job compared to the welding heat consumed in the previous welding job is compensated for by the stored energy related to the heat storage of the horn or anvil and the secondary vibration energy applied by the ultrasonic oscillator, and the position of the vibration unit is controlled so that the amount of sinking of the seal protrusion is kept approximately constant within a predetermined range for the pressure-welded part, whose hardness changes depending on the temperature related to the compensated energy, and an appropriate amount of energy is applied to the pressure-welded part from the start of sealing, thereby preventing the occurrence of sealing defects such as insufficient sealing or broken sealing.

[0020] Furthermore, according to the control method of the ultrasonic sealing device of the present invention, in an ultrasonic sealing device having a pressing process in which the pressure-welded portion is pressed between the pressing surface and the seal ridge to perform a pressure-welding process, and a welding process in which the pressure-welded portion is welded at a predetermined sealing temperature by friction of the pressing surface, a vibration frequency output process is provided in the vibration sensor to detect the main vibration frequency of the main ultrasonic vibration of the ultrasonic oscillator and output a main frequency signal based on the main vibration frequency to the control unit, and the control unit to which the main frequency signal is input has a vibration frequency output process in which the ultrasonic oscillator is held in a state from the start time of input of the main frequency signal to a predetermined detection time. The method includes a total applied heat calculation step for calculating the total applied heat amount related to the primary vibration energy applied to the horn, a total surplus heat calculation step for converting the applied heat related to the primary vibration energy applied to the horn into frictional heat, subtracting from the frictional heat the welding heat consumed in the previous work of welding the pressure-welded parts between the horn and the anvil to calculate the surplus heat from the frictional heat, and calculating the total surplus heat from the input start time to the detection time, and a deficit energy calculation step for subtracting the total surplus heat from the total applied heat at the specified detection time to calculate the energy that is insufficient for welding heat for the subsequent work of welding the pressure-welded parts. This makes it possible to calculate the maximum deficit energy that must be applied to the horn, and by applying energy equivalent to the deficit energy using the ultrasonic oscillator, sufficient welding heat can be obtained to be consumed in the subsequent work of welding, thereby realizing energy savings in the ultrasonic sealing device. Furthermore, the control unit is provided with an environmental temperature calculation process that calculates the amount of heat stored in the horn and anvil at the time of detection by subtracting the amount of heat dissipated by a cooling device or natural cooling from the excess heat, and also calculates the environmental temperature in the vicinity, including the horn and anvil, related to the heat storage. As a result, the ultrasonic oscillator only needs to apply the energy obtained by subtracting the amount of stored energy related to heat storage from the above-mentioned energy deficiency as secondary vibration energy, thereby achieving further energy savings in the ultrasonic sealing device. In this way, according to the control method of the ultrasonic sealing device of the present invention, the vibration control signal output from the control unit feeds back the main ultrasonic vibration previously output by the ultrasonic oscillator, and of the welding heat consumed in the work of welding the pressure-welded parts, the surplus heat accumulated in the horn and anvil is carried over to the work of the next welding, minus the welding heat consumed in the previous welding work, to compensate for the welding heat shortage in the next welding work, and any energy shortage even after the compensation is made up for by the secondary vibration energy of the secondary ultrasonic vibration output later by the ultrasonic oscillator. This makes it possible to sufficiently weld by compensating for the minimum necessary amount of energy deficiency, thereby realizing energy conservation in the ultrasonic sealing device. The control unit outputs a position control signal to the actuator to move the horn connected to the vibration unit toward or away from a predetermined position based on the compensated secondary vibration energy and the ambient temperature related to the carried-over heat storage. This allows the actuator to maintain a substantially constant amount of depression of the seal ridge pressed during welding within a predetermined range, even if the pressure-welded portion melts or its hardness changes due to the temperature based on the applied or carried-over energy. As a result, the amount of depression of the seal ridge can be optimized for the pressure-welded portion, whose hardness changes depending on the ambient temperature. Therefore, according to the control method of the ultrasonic sealing device of the present invention, the shortage of welding heat consumed in the next welding job compared to the welding heat consumed in the previous welding job is compensated for by the stored energy related to the heat storage of the horn or anvil and the secondary vibration energy applied by the ultrasonic oscillator, and the position of the vibration unit is controlled so that the amount of sinking of the seal protrusion is kept approximately constant within a predetermined range for the pressure-welded part, whose hardness changes depending on the temperature related to the compensated energy, and an appropriate amount of energy is applied to the pressure-welded part from the start of sealing, thereby preventing the occurrence of sealing defects such as insufficient sealing or seal breakage.

[0021] Furthermore, with the ultrasonic sealing device or the control method for the ultrasonic sealing device according to the present invention, the optimized sinking amount is preferably in the range of 10 μm to 200 μm, and particularly when welding synthetic resins for retort pouches, the sinking amount is preferably in the range of 60 μm to 75 μm. By optimizing the sinking amount during pressure welding within this range, poor sealing can be prevented. Preferably, the energy deficiency at a given detection time is set to be approximately constant from the input start time, so that when the ultrasonic sealing device warms up through repeated pressure welding and welding and cools down due to an emergency stop or the like, the oscillation frequency of the ultrasonic oscillator can be made to follow the warmth, and secondary vibration energy, excluding stored energy, from the energy deficiency can be applied to the horn, thereby realizing energy savings in the ultrasonic sealing device. The objects to be sealed by the ultrasonic sealing device are packaging bags or packaging containers, which allows the ultrasonic sealing device to be incorporated into packaging machines, thereby realizing energy savings and eliminating sealing defects. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is an explanatory diagram showing an outline of the configuration of an ultrasonic sealing device according to an embodiment of the present invention; [Figure 2] FIG. 2 is a partially enlarged view showing the outline of the configuration of the horn and anvil of the ultrasonic sealing device according to the present embodiment. [Figure 3] 1 is a block diagram showing an outline of a configuration related to control of an ultrasonic sealing device according to an embodiment of the present invention. [Figure 4] FIG. 2 is a flow chart showing an outline of the steps involved in the control method of the ultrasonic sealing device according to the present embodiment. [Figure 5] FIG. 2 is a graph showing the relationship between frequency and energy of the ultrasonic sealing device according to the present embodiment. [Figure 6] 4 is a graph showing the relationship between the energy and the sinking amount of the ultrasonic sealing device according to the present embodiment. FIG. Example 1

[0023] An embodiment of an ultrasonic sealing device according to the present invention will be described with reference to the accompanying drawings, in which: Figure 1 is an explanatory diagram showing the outline of the configuration of the ultrasonic sealing device according to this embodiment;

[0024] The ultrasonic sealing device 10 is composed of a device main body 11, a holder 12 that suspends and supports the device main body 11 and attaches it to a packaging machine (not shown), and a control unit 13 that controls the operation of the ultrasonic sealing device. Here, the ultrasonic sealing device 10 is incorporated into a packaging machine via a holder 12 for use. Therefore, the objects to be sealed by the ultrasonic sealing device 10 of this embodiment are preferably packaging bags, packaging containers, or similar packages. The ultrasonic sealing device 10 applies ultrasonic vibrations to the sealed object at a predetermined pressure to fix the sealed object, then applies ultrasonic vibrations to the sealed object, welding the pressed portion with frictional heat generated by the ultrasonic vibrations. Therefore, the packages to be sealed by the ultrasonic sealing device 10 incorporated into a packaging machine are preferably, for example, packaging bags, with at least the opening of the bag provided with a heat-sealable synthetic resin film, such as polyethylene or polypropylene, that melts at a predetermined temperature and hardens when cooled. Furthermore, for packaging containers, it is preferable that a heat-sealable film can be welded to the periphery of the packaging container to form a lid. Note that the objects to be sealed are not limited to the above-mentioned packages. The ultrasonic sealing device 10 of this embodiment can be applied to equipment other than packaging machines that includes a process for welding one heat-sealable material to another heat-sealable material. In the following, the present embodiment will be described using packaging bag B as an example. Packaging bag B has a pressure-welded area made of a heat-sealable film at least at the bag opening, and a clamped area formed near the pressure-welded area for clamping and fixing packaging bag B when sealing with ultrasonic sealing device 10, and is, for example, a retort pouch bag with a polyethylene film on the inside surface of the bag opening.

[0025] As shown in FIG. 1, the device main body 11 has a vibration unit 14, a horn 15, and an anvil 16. The vibration unit 14 has an output shaft 17, which is connected to an ultrasonic oscillator 18 inside the vibration unit 14. The output shaft 17 is configured to output a predetermined ultrasonic vibration from the vibration unit 14. The ultrasonic oscillator 18 is configured to oscillate at a predetermined vibration frequency, particularly at a vibration frequency in the ultrasonic band of 20 kHz or higher. Note that the ultrasonic oscillator 18 according to this embodiment is configured to be able to freely change the vibration frequency in the band of 39.0 kHz to 40.0 kHz. Using the ultrasonic oscillator 18 and the output shaft 17, the vibration unit 14 can adjust the vibration frequency associated with the ultrasonic vibrations to be output, and apply vibration energy associated with that vibration frequency to the pressure-welded portion of the packaging bag B.

[0026] 1, horn 15 is connected and fixed to the tip of output shaft 17. This allows the ultrasonic vibrations output from vibration unit 14 to be transmitted to horn 15. Horn 15 has a pressing surface 20 at its tip. 1 and 2, the anvil 16 is disposed opposite the horn 15. This allows the anvil 16 to receive the ultrasonic vibrations output from the vibration unit 14 and transmitted to the horn 15. The anvil 16 has a receiving surface 21 opposite to the pressing surface 20. When viewed in vertical cross section as shown in Figure 2, receiving surface 21 has sealing ridge 22 with an arc-shaped apex located approximately in the center of receiving surface 21. Seal ridge 22 is configured so that when it abuts against pressing surface 20, its apex makes linear contact with pressing surface 20. As a result, when the area to be pressure-welded is sandwiched between pressing surface 20 and sealing ridge 22 and pressure-welded, and ultrasonic vibrations are applied, frictional heat is generated between pressing surface 20 of vibrating horn 15 and the area to be pressure-welded, and the area to be pressure-welded is welded in a linear manner. 2, the anvil 16 is formed with a tapered surface 23 that is connected to the sealing ridge 22. This allows the packaging bag B to escape toward the tapered surface 23 when the pressure-welded area is sealed, thereby preventing areas other than the pressure-welded area from coming into contact with the horn 15 or the anvil 16. Furthermore, as shown in Fig. 2, the anvil 16 has a clamping ridge 24 formed on the receiving surface 21 on the opposite tapered surface side of the sealing ridge 22. Meanwhile, the horn 15 has a slot 25 formed in approximately the center of the pressing surface 20, as shown in Fig. 2. The width of the slot 25 is such that the clamping ridge 24 fits loosely into it. This allows the clamping ridge 24 to press the portion of the packaging bag B to be clamped into the slot, as shown in Fig. 2. Therefore, when the vicinity of the opening of the packaging bag B is set between the horn 15 and the anvil 16 and the horn 15 is pressed against the anvil 16, the packaging bag B is clamped between the pressing surface 20 and the receiving surface 21, and the clamping ridge 24 presses the portion of the packaging bag B to be clamped into the slot 25, thereby fixing the packaging bag B between the horn 15 and the anvil 16. In this case, it is preferable that the top of the clamping ridge 24 is formed in a substantially semicircular shape in vertical cross section, as shown in Fig. 2. This prevents damage to the clamped portion when the clamping ridge 24 pushes the clamped portion into the slot 25.

[0027] 1, the holder 12 has a main frame 30. A left and right ball screw 31, a bearing 32, a servo motor 33, a first linear guide rail 34, and first slide frames 35a and 35b are assembled in predetermined positions on the main frame 30. These components work together to freely move the horn 15 connected to the tip of the output shaft 17 of the vibration unit 14 and the anvil 16 facing the horn 15 toward or away from each other. The horizontal ball screw 31 is assembled to a bearing fixed to the main frame 30. A servo motor 33 is connected to one end of the horizontal ball screw 31, and the servo motor 33 is fixed to the main frame 30. Hereinafter, the servo motor 33 will be referred to as a first actuator that rotates the horizontal ball screw 31 relative to the main frame 30. 1, a pair of left and right first slide frames 35a, 35b are assembled to the horizontal ball screw 31. A plurality of first guide protrusions 36 are fixed to the lower ends of the first slide frames 35a, 35b. The first guide protrusions 36 are slidably fitted to the first linear guide rail 34. When the first actuator (servo motor 33) rotates the horizontal ball screw 31, the first slide frames 35a, 35b arranged on the left and right sides of the horizontal ball screw 31 move the first guide protrusions 36 fixed to the first slide frames 35a, 35b in directions opposite to each other. At this time, the first linear guide rail 34 in which the first guide protrusions 36 are fitted can guide the first slide frames 35a, 35b so that they move closer to or farther away from each other in directions opposite to each other. When the ultrasonic sealing device 10 is incorporated into a packaging machine (not shown) via the holder 12, the first actuator (servo motor 33) is configured to operate the left and right ball screw 31 when the space between the pressing surface 20 of the horn 15 and the receiving surface 21 of the anvil 16 is open, to set the initial value of the distance between the pressing surface 20 and the receiving surface 21 when the packaging bag B being conveyed is placed between the horn 15 and the anvil 16, or to replace the horn 15 or the anvil 16 depending on the type, shape, and thickness of the packaging bag B. This allows the ultrasonic sealing device 10 to be placed in a predetermined position on the packaging machine in accordance with the type, shape, etc. of the packaging bag B, and to optimally adjust the sealing position of the packaging bag B being conveyed on the packaging machine. Note that the configuration for placing the ultrasonic sealing device 10 at a predetermined position on the packaging machine and the configuration for adjusting the sealing position of the packaging bag B being transported on the packaging machine are not limited to this. For example, in a packaging machine in which the packaging bag B is transported along a predetermined circular or track-shaped transport path, if the main drive shaft that transports the packaging bag B is configured to drive each device, such as the ultrasonic sealing device, arranged along the transport path via a cam linked to the main drive shaft, or a chain, belt, etc. connected to the main drive shaft, instead of the servo motor 33 and left and right ball screws 31 of this embodiment, the main drive shaft and cam link, chain, belt, etc. may be used as a first actuator to freely control the distance between the horn 15 and the anvil 16 to move closer or farther apart.

[0028] As shown in FIG. 1, the anvil 16 is fixed to the lower end of one of the first slide frames 35a. As shown in FIG. 1, a second linear guide rail 37 extending parallel to the first linear guide rail 34 is fixed to the other first slide frame 35b. A plurality of second guide protrusions 38 are slidably fitted to the second linear guide rail 37. A second slide frame 39 is fixed to the second guide protrusions 38. The vibration unit 14 of the device main body 11 and a linear encoder 40 are fixed to the second slide frame 39. In this case, the position at which the second slide frame 39 fixes the vibration unit 14 is preferably a position that becomes a vibration node of the vibration unit 14 that resonates with the ultrasonic vibration when the ultrasonic oscillator 18 in the vibration unit 14 is ultrasonically vibrated. This prevents the vibration of the vibration unit 14 from propagating to the main frame 12 via the second slide frame 39. 1, an air cylinder 41 is fixed to the first slide frame 35b. That is, when the first slide frame 35b slides along the first linear guide rail 34 in accordance with the rotation of the horizontal ball screw 31, the air cylinder 41 moves, and the vibration unit 14 and the linear encoder 40 move together with the second slide frame 39 along the second linear guide rail 37. The second linear guide rail 37 is provided with optical or mechanical scales (not shown) at predetermined intervals. The linear encoder 40 has a sensor that can optically or mechanically detect the scales, and is configured to use the sensor to detect the movement distance of the linear encoder 40 that moves on the second linear guide rail 37 together with the second slide frame 39, and to output the movement distance as an electrically converted position signal to the control unit 13. This allows the control unit 13 to obtain the movement distance of the vibration unit 40 that is fixed to the second slide frame 39 together with the linear encoder 40, and the control unit 13 is fed back with the results of a series of operations in which the first actuator and the second actuator work together to move the horn 15 toward or away from the anvil 16. The air cylinder 41 has a rod 42 connected to the side opposite the horn of the vibration unit 14. Hereinafter, the air cylinder 41 will be referred to as a second actuator that presses the vibration unit 14 via the rod 42. 1, the anvil 16 is fixed to the first slide frame 35a side, and the horn 15 is fixed to the first slide frame 35b side, so when the first actuator (servo motor 33) moves the first slide frames 35a and 35b closer to each other, the pressing surface 20 of the horn 15 and the receiving surface 21 of the anvil 16 approach each other to a predetermined distance. This is the reference distance for opening, and at this time, the vicinity of the opening of the packaging bag B is inserted or pulled out between the pressing surface 20 and the receiving surface 21. When the vicinity of the opening of the packaging bag B is inserted between the pressing surface 20 and the receiving surface 21, the first actuator (servo motor 33) operates to rotate the left-right ball screw 31 in a direction in which the first slide frames 35a, 35b approach each other. As a result, as shown in Fig. 2, the pressing surface 20 of the horn 15 is brought into contact with the pressure-contact portion of the packaging bag B, and the clamping protrusions 24 of the anvil 16 are pushed into the slots 25 of the horn 15 to clamp the pressure-contact portion of the packaging bag B, thereby fixing the packaging bag B between the horn 15 and the anvil 16. Here, when the pressing surface 20 of the horn 15 is brought into contact with the pressure-contact portion of the packaging bag B, a second actuator (air cylinder 41) may apply pressure at a predetermined air pressure to assist the first actuator (servo motor 33). After the packaging bag B is fixed between the horn 15 and the anvil 16, the first actuator (servo motor 33) further rotates the left and right ball screw 31 in directions in which the first slide frames 35a, 35b approach each other, pressing the pressing surface 20 against the seal ridge 22 to press the pressure-welded portion. Alternatively, instead of the first actuator (servo motor 33), a second actuator (air cylinder 41) may control the amount of air taken in to press the pressing surface 20 against the seal ridge 22 to press the pressure-welded portion, or the first and second actuators may be combined appropriately to press the pressure-welded portion. The pressure-welded portion of the packaging bag B is then welded by frictional heat generated by vibrating the pressing surface 20 of the horn 15 with a predetermined ultrasonic vibration. When the pressure-welded portions are welded while applying pressure using either or both of the first and second actuators as described above, the thickness of the pressure-welded portions before welding is used as a reference, and the portions of the pressure-welded portions that have melted or softened due to frictional heat are pressed by the sealing ridges 22, causing the sealing ridges 22 to sink a predetermined amount. The position where the sealing ridges 22 abut before welding is used as a reference, and the amount by which the sealing ridges 22 sink into the pressure-welded portions from this reference position is defined as the sinking amount. The sinking amount is detected by the rotation angle of the rotary shaft of the first actuator (servo motor 33), or by either or both of the second linear guide rail 37 and linear encoder 40, and is output to the control unit 13.

[0029] As described above, the ultrasonic sealing device 10 is configured such that the actuators slide the slide frames attached to the main frame 30 of the holder 12 along the linear guide rails, thereby clamping the packaging bag B between the horn 15 and the anvil 16 and pressing the pressing surface 20 toward the receiving surface 21 to fix the packaging bag B. Ultrasonic vibrations are applied from the horn 15 to the fixed packaging bag B, and the pressure-welded portion pressed toward the pressing surface 20 by the sealing ridge 22 is welded and sealed by frictional heat. 1 and 3, the ultrasonic sealing device 10 is preferably configured so that the axis of the rod 42, the central axis of the vibration unit 14, the axis of the output shaft 17, the central axis passing through the slit 25 of the horn 15, and the central axis of the clamping ridge 24 of the anvil 16 are all aligned in a substantially straight line. This allows the pressure applied by the air cylinder 41 to the rod when the second actuator (air cylinder 41) presses in the rod 42 to be transmitted to the pressing surface 20 of the horn 15 without deviation, preventing the horn 15 or the anvil 16 from slipping against the pressure-welded portion while the horn 15 is vibrating with ultrasonic vibrations, thereby preventing poor sealing.

[0030] The control unit 13 includes a vibration sensor 50 as shown in FIG. The vibration sensor 50 is configured to detect the vibration frequency from the ultrasonic oscillator 18 of the vibration unit 14 regarding the ultrasonic vibrations applied by the horn 15 to the pressure-welded portion, convert the vibration frequency into a frequency signal, and output it to the control unit 13. The control unit 13 is configured to analyze the frequency signal input from the vibration sensor 50 and control the vibration unit unit 11, the first actuator (servo motor 33), and the second actuator (air cylinder 41) mutually or independently of each other based on the vibration frequency fed back. In addition, the control unit 13 is configured so that a position signal related to information on the movement distance of the vibration unit 14 output from the linear encoder 40 is input to the control unit 13. Furthermore, the position signal is not limited to the signal output from the linear encoder 40, and a signal related to the rotation angle of the rotation shaft of the first actuator (servo motor 33) may also be used. In this way, position information related to the sinking amount of the sealing ridge 22 is fed back to the control unit 13. Based on the sinking amount related to the fed-back position signal, the first actuator (servo motor 33) and the second actuator (air cylinder 41) are controlled mutually or independently of each other.

[0031] Here, the relationship of the following formula 1 holds between the vibration frequency λ of the frequency signal and the ultrasonic energy E of the ultrasonic vibration oscillated by the ultrasonic oscillator, where ν is the Planck constant.

[0032]

number

[0033] When the ultrasonic oscillator 18 oscillates, ultrasonic energy E proportional to the vibration frequency λ is applied to the pressing surface 20 of the horn 15 via the output shaft 17 and the horn 15. At this time, the ultrasonic energy E is converted into frictional heat at the pressure-welded portion sandwiched between the pressing surface 20 and the sealing ridge 22, thereby performing work. Assuming that all of the ultrasonic energy E is converted into frictional heat without loss and applied to the horn 15, this is referred to as applied heat. Of the applied heat, the heat consumed in the work of welding the pressure-welded portion is referred to as welding heat. The remaining heat is comprised of stored heat accumulated in the horn 15 or anvil 16 and heat dissipated from the horn 15 or anvil 16 due to cooling. This heat is surplus heat that is not consumed in the work related to welding. As long as the amount of heat dissipated from the horn 15 or anvil 16 is greater than the amount of heat stored, the horn 15 or anvil 16 can be said to be cool. On the other hand, when the amount of heat dissipated becomes smaller than the amount of heat stored, i.e., when heat dissipation cannot keep up with heat storage, the temperature of the horn 15 or the anvil 16 gradually rises. The amount of heat related to this gradually rising temperature becomes excess heat when welding the pressure-welded portion. Therefore, when the ultrasonic oscillator 18 is constantly vibrating at a constant state, in addition to the heat related to the temperature of the horn 15 or anvil 16, which rises over time, a constant amount of ultrasonic energy E is constantly applied from the ultrasonic oscillator 18. This causes an excessive amount of ultrasonic energy E to be supplied to the horn 15, and the residual heat in the horn 15 or anvil 16 and the excess ultrasonic energy E may cause excessive welding and sealing not only of the pressure-welded portion of the packaging bag B but also of the surrounding area, resulting in a defective seal. On the other hand, if the ultrasonic energy E to be applied is set assuming a steady state in which the temperature of the horn 15 or anvil 16 is stable in order to prevent excessive welding, then in the transient state immediately after the ultrasonic sealing device 10 is put into operation, the amount of heat dissipated will be greater than the amount of heat stored, as described above, and the horn 15 or anvil 16 will be cold. In this case, the supply of ultrasonic energy E will be insufficient, and the heat-sealable resin in the pressure-welded portion of the packaging bag B will not melt sufficiently, which could result in poor sealing due to insufficient welding. Similarly, if the amount of depression of the sealing ridge 22 is set to match the steady state, the amount of depression will be insufficient in the transient state, which could further induce poor sealing. In this embodiment, in the case of packaging bag B made of a retort pouch bag with a polyethylene film, the recession amount of sealing ridge 22 is preferably 60 μm to 75 μm. If it is less than 60 μm, i.e., if the recession amount is small, there is a risk of poor sealing due to insufficient pressure contact. On the other hand, if it exceeds 75 μm, i.e., if the recession amount is large, there is a risk of poor sealing due to excessive welding. When applying the ultrasonic sealing device 10 according to this embodiment to other packaging bags or containers or similar packages that include a heat-sealable synthetic resin film, not limited to the packaging bag B made of a retort pouch bag in this embodiment, the most preferable sinking amount of the sealing ridge 22 can be selected as desired within the range of 10 μm to 200 μm. Even in this case, if the sinking amount is less than 10 μm, i.e., if the sinking amount is small, there is a risk of poor sealing due to insufficient pressure. On the other hand, if the sinking amount is more than 200 μm, i.e., if the sinking amount is large, there is a risk of poor sealing due to excessive welding.

[0034] Therefore, it is important for control unit 13 to take into account the heat quantity of horn 15 or anvil 16, which gradually increases over time, and to appropriately control the ultrasonic vibrations that vibrator unit 14 causes ultrasonic oscillator 18 to generate, thereby optimizing the ultrasonic energy E applied to horn 15. It is also important to optimize the amount of sinking of sealing protrusion 22 into the melted or softened pressure-welded portion when the optimized ultrasonic energy E seals the pressure-welded portion. Therefore, control unit 13 is configured to control the subsequent vibration frequency by feeding back the amount of energy related to the heat quantity of horn 15 or anvil 16, etc., based on the previous vibration frequency detected by vibration sensor 50, and to control the subsequent sinking amount based on the previous sinking amount fed back from linear encoder 40 or preferably the first actuator (servo motor 33). Here, the ultrasonic vibration is referred to as the main ultrasonic vibration, and the vibration frequency at that time is referred to as the main vibration frequency. On the other hand, the ultrasonic vibration after being feedback-controlled and optimized is referred to as the secondary ultrasonic vibration, and the vibration frequency at that time is referred to as the secondary vibration frequency. The control unit 13 has a first control system that vibrates the horn 15 with a predetermined ultrasonic vibration, and a second control system that applies a predetermined pressure to the horn 15 toward the anvil 16 to ensure a reliable seal. The first control system controls the ultrasonic oscillator 18 to generate an optimized secondary ultrasonic vibration based on a main frequency signal related to the main vibration frequency detected by the vibration sensor 50. The second control system controls the first actuator (servo motor 33) and the second actuator (air cylinder 41) based on a position signal fed back from the first actuator (servo motor 33) or the linear encoder 40 to press the horn 15 against the anvil 16 with an optimal force and press the pressure-welded portion with an optimized sinking amount. The first control system and the second control system will be described below.

[0035] For the first control system, the control unit 13 first calculates the total amount of ultrasonic energy applied by the ultrasonic oscillator 18 to the horn 15 from the input start time t0, i.e., the time when the ultrasonic sealing device starts operating, to the predetermined detection time t. Here, assuming that losses are negligibly small and all of the ultrasonic energy is converted into frictional heat, the heat based on the ultrasonic energy applied to the horn 15 is taken as the applied heat, and the total amount is taken as the total applied heat. By subtracting the heat consumed by the welding heat consumed by the horn 15 and anvil 16 in their work of welding the pressure-welded parts from the total amount of applied heat, the excess heat not consumed by the horn 15 and anvil 16 in their work of welding at the detection time t can be determined. When welding the pressure-welded portion, the welding temperature required to melt the heat-fusible resin is known, and the welding heat consumed in the work related to the welding is also a known quantity. By integrating this from the input start time t0 to the predetermined detection time t, the total amount of welding heat consumed by the horn 15 or anvil 16 in the work related to the welding can be calculated. Therefore, the total amount of excess heat, i.e., the total amount of excess energy other than the welding heat consumed by the horn or anvil in the work related to welding from the input start time t0 to the specified detection time, is calculated, and the amount of heat obtained by subtracting the total amount of excess heat from the total amount of applied heat is the amount of heat that is insufficient for the next welding work of the horn 15 and anvil 16 at the specified detection time t.

[0036] Here, the excess heat at a given detection time t consists of the stored heat in the horn 15 or anvil 16 and the radiated heat dissipated from the horn 15 or anvil 16 either naturally or after being cooled by a cooling device or the like. Therefore, by subtracting the radiated heat from the excess heat, the stored heat in the horn 15 or anvil 16 can be obtained. Here, if the stored energy related to the heat storage is Q, the mass of the horn 15 or anvil 16 is m, the specific heat is c, and the temperature is T, the temperature of the horn 15 or anvil 16 based on the stored heat in the horn 15 or anvil 16 can be calculated from Equation 2. Hereinafter, this temperature will be referred to as the ambient temperature of the horn 15 and anvil 16 surrounding the pressing surface 20 and the sealing ridge 22.

[0037]

number

[0038] Then, by subtracting the stored energy related to heat storage from the heat deficiency, the heat required for the work related to welding, i.e., the vibration energy that ultrasonic oscillator 18 should next apply to horn 15, can be calculated. Based on the relationship in Equation 1, control unit 13 calculates the vibration frequency that ultrasonic oscillator 18 should oscillate at in order to satisfy the vibration energy that should be applied. Hereinafter, this vibration frequency will be referred to as the subordinate vibration frequency, and the vibration energy related to this subordinate vibration frequency will be referred to as the subordinate vibration energy. A vibration control signal related to the calculated subordinate vibration frequency is output to vibration unit 14, and vibration unit 14 is configured to adjust the subordinate ultrasonic vibration oscillated by ultrasonic oscillator 18 based on the vibration control signal.

[0039] Next, regarding the second control system, the control unit 13 outputs a position control signal to the first actuator (servo motor 33) or the second actuator (air cylinder 41) to move the vibration unit unit 14 to which the horn 15 is connected to a predetermined position based on the ambient temperature of the horn 15 and the anvil 16 obtained by the first control system, and is configured to control the pressing force with which the first actuator (servo motor 33) presses the horn 15 against the anvil 16, or the pressing force with which the second actuator (air cylinder 41) presses the horn 15 against the anvil 16 via the rod 42. Here, at detection time t, the amount of heat deficit related to the energy deficiency, which is the sum of the secondary vibration energy and the stored energy, is approximately the same as the initial amount of heat related to the ultrasonic energy E applied by the ultrasonic oscillator 18 to the horn 15 at input start time t0. It is preferable that the amount of heat deficit, i.e., the sum of the secondary vibration energy and the stored energy, is constant from input start time t0 to detection time t. That is, when the environmental temperature is low, i.e., when the stored energy is small and a large secondary vibrational energy needs to be applied, the secondary vibration frequency related to the secondary vibrational energy becomes large. In addition, when the environmental temperature is low, the specific heat of the sealing ridges 22 is small, so the sealing ridges 22 are also cold, and the temperature of the pressure-welded portions of the packaging bag B is also low, so the pressure-welded portions are less likely to melt, and the sealing ridges 22 are less likely to sink into the pressure-welded portions. On the other hand, when the ambient temperature is high, that is, when the stored energy is large and the applied secondary vibration energy can be reduced, the secondary vibration frequency related to the secondary vibration energy can be reduced. In addition, when the ambient temperature is high, the sealing ridges 22, which have a small specific heat, heat up easily, and the temperature of the pressure-welded portions of the packaging bag B is also high, so the pressure-welded portions are easily melted, and the sealing ridges 22 are likely to sink into the pressure-welded portions. By reflecting the ambient temperature in this way and applying a constant amount of energy sufficient to weld the pressure-welded portion by adding the insufficient heat, the pressing surface 20 of the horn 15 can melt, weld, and seal the pressure-welded portion under approximately the same conditions, and based on the position control signal input to the first actuator (servo motor 33) or the second actuator (air cylinder 41), the amount of sinking of the vibration unit 14 connected to the horn 15 along the second linear guide rail 37 is fed back to the control unit 13 as a position signal output from the linear encoder 40 or a position signal related to the rotation angle of the rotation shaft of the first actuator (servo motor 33). This allows the sinking amount of the sealing protrusion 22 to be optimized and maintained within the range of 60 μm to 75 μm, which is preferred in this embodiment, in response to changes in ambient temperature, while applying to the horn 15 secondary ultrasonic vibrations with appropriate secondary vibration energy that satisfies the energy deficiency, thereby welding the pressure-welded portion of the packaging bag B.

[0040] According to the ultrasonic sealing device 10 of the present invention, the ultrasonic vibrations emitted by the ultrasonic oscillator 18 are changed in response to the temperature of the horn 15 or anvil 16, which gradually changes depending on the number of times the packaging bags B fed to the ultrasonic sealing device 10 have been sealed. In this case, the temperature sensor detects the temperature of the horn 15 or anvil 16, so instead of providing a new temperature sensor, the vibration sensor 50 used to check whether the ultrasonic oscillator 18 of the vibration unit 14 is emitting normally is reused. The control unit 13 is configured to estimate the temperature of the horn 15 or anvil 16 based on the main vibration energy of the previous ultrasonic vibration applied by the horn 15, and to calculate the secondary vibration energy of the subsequent ultrasonic vibration required for the next welding job. In this way, the amount of energy can be controlled based on the vibration frequency detected by the vibration sensor 50, thereby simplifying the configuration of the ultrasonic sealing device 10 and controlling the vibration unit 14 and ultrasonic oscillator 18 to seal the pressure-welded portion of the packaging bag B with stable sealing strength.

[0041] A control method for the ultrasonic sealing device 10 having the above configuration will be described below with reference to the accompanying drawings.

[0042] 4, the ultrasonic sealing device 10 includes a pressure-welding process in which the pressure-welded portion of the packaging bag B is clamped between the horn 15 and the anvil 16 and pressed to fix the pressure-welded portion, and a welding process in which the pressure-welded portion is welded. The pressure-welding process further includes a clamping process in which the packaging bag B is clamped between the horn 15 and the anvil 16, and a pressing process in which the packaging bag B is clamped and the horn 15 is pressed against the anvil 16.

[0043] In the clamping process, the first actuator (servo motor 33) rotates the left and right ball screws 31 to bring the horn 15 and the anvil 16 closer to each other, and as shown in Fig. 2, the clamping ridges 24 provided on the anvil 16 side are pushed into the slots 25 provided on the horn 15 side together with the packaging bag B, thereby clamping the clamped portion near the pressure-welded portion of the packaging bag B. As a result, the packaging bag B is clamped between the pressing surface 20 of the horn 15 and the receiving surface 21 of the anvil 16, and the packaging bag B can be fixed by the clamping ridges 24 and the slots 25. The pressing step is a step that follows the clamping step and involves using either or both of the first actuator (servo motor 33) and the second actuator (air cylinder 41) to strongly push the vibration unit 14 toward the anvil 16, thereby pressing the pressing surface 20 against the sealing ridge 22. As a result, when the pressure-welded area is sealed, the sealing ridge 22 sinks into the pressure-welded area that has been melted or softened by the vibration of the pressing surface 20, and the sealing ridge 22 can linearly seal a predetermined position of the pressure-welded area where it is pressed against the pressing surface 20. The amount of depression of the sealing ridge 22 into the pressure-welded portion of the pressing surface 20 in this pressing step is referred to as the depression amount. In this embodiment, the packaging bag B is a retort pouch bag with a polyethylene film. In this case, the amount of depression of the sealing ridge 22 is preferably 60 μm to 75 μm. If it is less than 60 μm, i.e., if the amount of depression is small, there is a risk of poor sealing due to insufficient pressure welding or insufficient melting of the pressure-welded portion. On the other hand, if it exceeds 75 μm, i.e., if the amount of depression is large, there is a risk of poor sealing due to excessive welding.

[0044] The welding process is a process that is carried out in parallel with the pressing process described above, in which the pressing surface 20, which is pressed against the sealing ridges 22 across the pressure-welded portion, is vibrated by ultrasonic vibrations transmitted to the horn 15 to generate frictional heat, and the frictional heat is used to weld the heat-sealable film arranged on the pressure-welded portion of the packaging bag B. As a result, the pressing surface 20 melts the pressure-welded portion while pressing the pressure-welded portion, causing the sealing ridges 22 to sink into the pressure-welded portion, and thereby linearly sealing the pressure-welded portion of the packaging bag B. The ultrasonic vibrations transmitted to the horn 15 are generated and output by an ultrasonic oscillator 18 connected to the base end of the output shaft 17 of the vibration unit 14. The vibration frequency output by the ultrasonic oscillator 18 is variable and is at least in the band of 20 kHz or more, preferably in the band of 39.0 kHz to 40.0 kHz.

[0045] As shown in FIG. 4, the control unit 13 includes a vibration frequency detection process, a total applied heat calculation process, a total surplus heat calculation process, an energy deficit calculation process, an environmental temperature calculation process, a vibration control process, and a position control process. The vibration frequency detection process is a process in which the vibration sensor 50 detects the vibration frequency of the ultrasonic vibration. This process is configured to detect the ultrasonic vibration oscillated by the ultrasonic oscillator 18 at a predetermined detection time t. The ultrasonic vibration detected at this time is defined as the main ultrasonic vibration, and the vibration frequency based on the main ultrasonic vibration is defined as the main vibration frequency. The vibration sensor 50 is configured to digitally modulate the analog main vibration frequency, which is detected as a finely and continuously changing signal, discretely over a predetermined bandwidth, converting it into a main frequency signal, and outputting the signal to the control unit 13.

[0046] The total applied heat calculation step is a step in which the control unit 13, to which the main frequency signal has been input, performs processing to calculate the total amount of applied heat associated with the main vibration energy applied to the horn by the main ultrasonic vibrations based on the main frequency signal, calculated from the time t0 when the main frequency signal input begins to the predetermined detection time t. The applied heat refers to the heat that occurs when the main vibration energy applied to the horn is converted into frictional heat and applied to the horn 15, assuming that the energy loss when transmitted from the ultrasonic oscillator 18 to the output shaft 17 to the horn 15 is negligibly small. The total applied heat calculation step makes it possible to find the total amount of heat associated with the main vibration energy applied by the ultrasonic oscillator 18 to the horn 15.

[0047] The total excess heat calculation process calculates the total amount of excess heat applied to the horn 15, i.e., the excess heat remaining after the welding heat consumed by the horn 15 and anvil 16 in welding work, from the start time t0 of the main frequency signal input to the predetermined detection time t. The excess heat consists of heat dissipated and diffused from the horn 15 and anvil 16 after natural cooling or cooling by a cooling device, and heat stored in the horn and anvil. Since the welding temperature of the heat-fusible film at the pressure-welded portion is known, the excess heat, i.e., excess energy, can be calculated by excluding the welding heat from the applied heat. The calculated excess heat is summed from the start time t0 of the main frequency signal input to the predetermined detection time t to calculate the total excess heat. Carrying over a portion of the excess heat, especially the stored heat, to the next welding process reduces the vibration energy newly applied to the horn 15, thereby improving energy conservation.

[0048] The energy deficit calculation process subtracts the total amount of excess heat from the total amount of applied heat. This process calculates the amount of heat deficit (i.e., the energy deficit) that is insufficient at detection time t relative to the welding heat consumed by the horn 15 and anvil 16 in the next welding process. When the amount of accumulated heat is small, a large proportion of the excess heat is consumed by welding heat, resulting in a small amount of excess heat and a large energy deficit. On the other hand, when the amount of accumulated heat increases, a smaller proportion is consumed by welding heat, resulting in a large amount of excess heat and a small amount of energy deficit. Therefore, as the amount of accumulated heat in the horn 15 or the anvil 16 increases and the temperature of the horn 15 or the anvil rises, the energy deficit decreases. Therefore, the amount of vibrational energy newly applied to the horn 15 can be reduced, and the vibration frequency of the ultrasonic vibrations generated by the ultrasonic oscillator 18 can be lowered.

[0049] The environmental temperature calculation process is a process in which the heat accumulated in the horn 15 or anvil 16 is calculated by excluding the heat dissipated by natural cooling or cooling by a cooling device or the like in the horn 15 or anvil 16 from the excess heat calculated in the total excess heat calculation process, and the environmental temperature of the horn 15 and anvil 16 surrounding the pressing surface 20 and the sealing ridge 22 is calculated based on the accumulated heat and taking into account the weight m and specific heat c of the horn 15 or anvil 16. If the calculated environmental temperature is low, i.e., if the stored energy is small and a large secondary vibration energy needs to be applied, processing is performed to control the ultrasonic oscillator 18 to emit ultrasonic waves at a large secondary vibration frequency. Furthermore, since the specific heat of the sealing ridges 22 protruding from the anvil 16 is small compared to the anvil 16 itself, when the environmental temperature is low, the sealing ridges 22 also tend to cool down easily, and the pressure-welded portions of the packaging bag B that come into contact with the sealing ridges 22 are also less likely to heat up or melt, making it difficult for the sealing ridges 22 to sink into the pressure-welded portions. Therefore, processing is performed to control either one or both of the first actuator (servo motor 33) and the second actuator (air cylinder 41) to apply a strong pressure. On the other hand, when the ambient temperature is high, that is, when the stored energy is large and the applied secondary vibration energy can be reduced, the ultrasonic oscillator 18 is controlled to emit ultrasonic waves at a low secondary vibration frequency. Furthermore, when the ambient temperature is high, the anvil 16 is already warm, the sealing ridges 22 heat up easily, and the pressure-welded portions of the packaging bag B also heat up easily and melt easily, making the sealing ridges 22 more likely to sink into the pressure-welded portions. Therefore, control is performed to suppress the pressing force on either or both of the first actuator (servo motor 33) and the second actuator (air cylinder 41). Therefore, based on the calculated ambient temperatures of the horn 15 and the anvil 16, the control unit 13 performs processing to output a position control signal to either or both of the first actuator (servo motor 33) or the second actuator (air cylinder 41) to move the vibration unit 14 to which the horn 15 is connected, toward or away from a predetermined position, and also performs processing to output a vibration control signal related to the secondary vibration frequency to the vibration unit 14. In this way, immediately after starting the ultrasonic sealing device 10, while the horn 15 or anvil 16 is cold, the vibration energy applied to the horn 15 is increased, and as the number of seals increases in the welding process, the horn 15 or anvil 16 gradually warms up, and when the excess heat not consumed as welding heat becomes large, the excess heat from the previous packaging bag is consumed as part of the welding heat for the subsequent packaging bag, thereby reducing the vibration energy applied to the horn 15. In other words, by consuming the excess heat as part of the welding heat, the increase in heat storage or heat radiation that constitutes the excess heat is suppressed, and the temperature rise of the horn 15 or anvil 16 is suppressed without using an excessive cooling device, allowing for sealing with stable seal strength for a long period of time. As a result, the cost of cooling devices such as water cooling, oil cooling, or forced air cooling, which were previously required, can be reduced.

[0050] Here, in the pressing step, when the horn 15 and the anvil 16 are cold, the pressure-welded portion of the clamped packaging bag B is cold and difficult to melt, and the sealing ridges 22 are difficult to sink into the pressure-welded portion. On the other hand, when the horn 15 and the anvil 16 are warm, the pressure-welded portion of the clamped packaging bag B is warm and easy to melt, and the sealing ridges 22 are easy to sink into the pressure-welded portion. Furthermore, in the welding process, after sealing the first packaging bag B, the sealing ridges 22 protruding from the anvil 16 have a smaller specific heat than the anvil 16 itself and therefore experience a larger temperature change during the sealing of the second packaging bag B. Therefore, the sealing ridges 22 cool easily when the anvil 16 is cold, and do not cool easily when the anvil 16 is warm. In this way, during the pressing and welding processes, the amount of sinking of the sealing ridge 22 into the pressure-welded area, which changes in ease of melting depending on the vibration energy applied to the horn 15 and the heat stored in the pressing surface 20 and the sealing ridge 22, also changes, so the ambient temperature and the secondary vibration frequency are major factors in stably sealing the pressure-welded area. Therefore, the above-mentioned environmental temperature calculation process, vibration control process, and position control process are configured to be performed in parallel with both or either one of the pressure welding process and the welding process, including the pressing process. As a result, the first actuator (servo motor 33) or the second actuator (air cylinder 41) can be controlled in accordance with the environmental temperature, which changes from time to time during the pressure welding process or the welding process, to keep the amount of sinking constant within a predetermined range, and the ultrasonic oscillator 18 can be controlled in accordance with the necessary secondary vibration frequency to be applied, which also changes from time to time, to output the optimal secondary ultrasonic vibration.

[0051] The vibration control process is a process of calculating a secondary vibration frequency related to the secondary vibration energy to be applied to the horn 15 from the energy deficiency that is insufficient for welding calculated in the energy deficiency calculation process, taking into account the environmental temperature calculated in the environmental temperature calculation process, and outputting a vibration control signal related to the calculated secondary vibration frequency from the control unit 13 to the vibration unit 14.

[0052] The vibration unit 14, to which the vibration control signal is input, has a welding control process that causes the ultrasonic oscillator 18 to oscillate with a subordinate ultrasonic vibration based on the vibration control signal, whereby the subordinate vibration energy associated with the subordinate ultrasonic vibration is applied to the horn 15 via the output shaft 17, generating frictional heat between the pressing surface 20 and the sealing ridge 22, thereby welding the pressure-welded portion. 5 is a graph showing the relationship between the secondary vibration frequency of the ultrasonic oscillator 18 and the secondary vibration energy applied to the horn 15 during the welding control process. The horizontal axis of this graph represents the number of times packaging bags B are fed between the horn 15 and the anvil 16, and the vertical axis represents the vibration frequency (kHz) of the ultrasonic oscillator 18 and the secondary vibration energy (J) applied to the horn 15. This graph shows that as sealing is repeated during the welding process, the vibration frequency detected by the vibration sensor 50 decreases. From this graph, it can be seen that the energy stored in the horn 15 or the anvil 16, which is surplus heat other than the heat consumed in the welding-related work during the previous welding process, is carried over to the subsequent welding process. As the ambient temperature around the horn 15 or the anvil 16 rises, the secondary vibration energy of the insufficient energy to be applied decreases, and the vibration frequency associated with the secondary ultrasonic vibrations emitted by the ultrasonic oscillator 18 decreases. Furthermore, since the vibration frequency detection process calculates the energy deficiency based on the main frequency signal obtained by digitally modulating the detected main vibration frequency, it can be seen that the secondary vibration energy to be applied to the horn 15 decreases in steps, taking discrete values, and when the frequency drops below approximately 39.52 kHz, the dissipated energy dissipated by cooling from the horn 15 or anvil 16 and the carried-over stored energy balance, and the secondary vibration energy applied to the horn 15 out of the energy deficiency becomes a constant value.

[0053] In the position control step, in order to adjust the position of vibration unit 14 based on the environmental temperature calculated in the environmental temperature calculation step, control unit 13 performs processing in which a predetermined position of the output shaft of first actuator (servo motor 33) is set as the initial position, and a position control signal is output to either or both of first actuator (servo motor 33) and second actuator (air cylinder 41) to control the rotation angle of the rotation shaft of first actuator (servo motor 33) in either the forward or reverse direction or to control rod 42, which moves forward and backward by the increased or decreased air pressure of second actuator (air cylinder 41). The amount of movement of vibration unit 14 as a result of the adjustment is fed back to control unit 13 by a position signal detected by linear encoder 40, which is fixed to second linear guide rail 37 together with vibration unit 14.

[0054] Either or both of the first actuator (servo motor 33) or the second actuator (air cylinder 41) to which the position control signal is input adjust the position of the vibration unit 14, adjust the horn 15 so that it can move toward or away from the anvil 16, and have a pressing control process that adjusts the optimal position when the sealing protrusion 22 is pressed against the pressing surface 20. In the pressing control step, a predetermined position of the rotation shaft of the first actuator (servo motor 33) is set as an initial position based on a position control signal input from the control unit 13, and the position of the vibration unit 14 relative to the initial position is fed back to the control unit 13 via the linear encoder 40 on the second linear guide rail 37. This makes it possible to set the initial position of the vibration unit 14, and therefore of the horn 15 connected to the vibration unit 14 via the output shaft 17. The initial position of the horn 15 refers to the position where the clamping ridge 24 contacts the clamped portion of the packaging bag B, just before the pressing surface 20 of the horn 15 and the receiving surface 21 of the anvil 16 come into contact with each other. From this point, when the first actuator (servo motor 33) is operated based on the position control signal to rotate the rotation shaft by a predetermined angle, the first slide frames 35a, 35b engaged with the left and right ball screws 31 move closer to each other, and the clamping ridges 24 clamp the clamped portion of the packaging bag B and push it into the slots 25. This allows the packaging bag B to be clamped and fixed between the horn 15 and the anvil 16. At the same time, the sealing ridges 22 contact the pressing surface 20 across the pressure-welded portion, and the pressure-welded portion begins to melt due to frictional heat generated by the applied ultrasonic vibrations, thereby initiating sealing. When the pressure-welded portion melts and softens due to the welding heat, one or both of the first actuator (servo motor 33) and the second actuator (air cylinder 41), which are pressing the sealing ridges 22 against the pressing surface 20, further press the sealing ridges 22 against the pressure-welded portion based on a position control signal. At this time, the pressing surface 20 of the horn 15 moves relative to the sealing ridges 22 on the anvil 16, and the vibration unit 14, which connects the horn 15, moves toward the anvil 16. The amount of movement, i.e., the amount of sinking, is detected by a linear encoder 40 fixed to the vibration unit 14 and fed back to the control unit 13 as a position signal. As a result, in the pressing control process, the first actuator (servo motor 33) is controlled based on the position control signal to set the initial positions of the vibration unit 14 and the horn 15, and either or both of the first actuator (servo motor 33) and the second actuator (air cylinder 41) are controlled to optimally adjust the amount of sinking of the sealing protrusion 22 into the molten pressure-welded portion. 6 is a graph showing the relationship between the secondary vibration energy applied to the horn 15 during the pressure control process and the amount of sinking of the sealing ridge 22. The horizontal axis of the graph represents the number of times packaging bags B are fed between the horn 15 and the anvil 16, and the vertical axis represents the secondary vibration energy (J) applied to the horn 15 and the amount of sinking (μm) of the sealing ridge 22 into the pressure-welded portion. From this graph, it can be seen that either or both of the first actuator (servo motor 33) and the second actuator (air cylinder 41) adjust the pressure with which they press the horn 15 in response to changes in the secondary vibration energy applied to the horn 15, thereby controlling the amount of sinking of the sealing ridge 22 to fall within a predetermined range. In this embodiment, a packaging bag B made of a retort pouch bag with a polyethylene film is used. In this case, as shown in Fig. 6, the amount of depression of the sealing ridge 22 is preferably 60 µm to 75 µm. If it is less than 60 µm, i.e., if the amount of depression is small, there is a risk of poor sealing due to insufficient pressure contact. On the other hand, if it exceeds 75 µm, i.e., if the amount of depression is large, there is a risk of poor sealing due to excessive welding.

[0055] According to the control method for the ultrasonic sealing device 10 of this embodiment, the vibration sensor 50 detects the primary ultrasonic vibration applied to the horn 15 in the previous welding step and outputs a primary frequency signal related to the primary ultrasonic vibration to the control unit 13. Based on the fed-back primary frequency signal, the control unit 13 determines the optimal secondary vibration frequency to be applied to the horn 15 when the sealing ridges 22 weld the pressure-welded portions in the subsequent welding step. The control unit 13 also controls the pressure applied by the pressure surface 20 to the sealing ridges 22 to optimize the amount of depression of the sealing ridges 22 into the pressure-welded portions of the packaging bag B that melt between the pressure surface 20 and the sealing ridges 22, within a predetermined range. This allows the ultrasonic sealing device 10 to apply optimal ultrasonic vibrations to the horn 15 in response to temperature changes in the horn 15 or anvil 16, thereby welding the pressure-welded portions with a stable seal strength from the start of sealing the packaging bag B. In addition, the ultrasonic sealing device 10 in this embodiment clamps the clamped portion between the clamping protrusion 24 of the anvil 16 and the slot 25 of the horn 15, thereby suspending and fixing the packaging bag B, but this is not limited to this, and for example, the layout of the ultrasonic sealing device 10 and the shapes of the horn 15 and anvil 16 may be changed as desired so as to weld the edge of a packaging container moving on a conveyor. [Explanation of symbols]

[0056] 10...Ultrasonic sealing device, 11... device body, 12... holder, 13... control section, 14... vibration section unit, 15... horn, 16... anvil, 17... output shaft, 18... ultrasonic oscillator, 20...Pressing surface, 21...Receiving surface, 22...Sealing ridge, 23...Tapered surface, 24...Clipping ridge, 25...Slot, 30...main frame, 31...left and right ball screws, 32...bearing, 33...servo motor (first actuator), 34...first linear guide rail, 35a, 35b...first slide frame, 36...first guide convex piece, 37...second linear guide frame, 38...second guide convex piece, 39...second slide frame, 40...linear encoder, 41...air cylinder (second actuator), 42...rod.

Claims

1. a horn having a pressing surface that transmits predetermined ultrasonic vibrations; an anvil having a receiving surface disposed opposite the pressing surface of the horn; a vibration unit having an ultrasonic oscillator that oscillates the ultrasonic vibration at a predetermined vibration frequency and an output shaft that outputs the ultrasonic vibration from the ultrasonic oscillator, the horn being connected to a tip of the output shaft; an actuator that holds the vibration unit so as to be freely movable toward and away from the anvil, and presses the pressing surface toward the receiving surface with a predetermined pressure when the horn connected to the vibration unit is brought close to the anvil; a vibration sensor that detects the vibration frequency of the ultrasonic oscillator; a control unit that controls the operation of both or either one of the vibration unit and the actuator based on the vibration frequency detected by the vibration sensor, A seal protrusion is formed at a predetermined position on either the pressing surface or the receiving surface, the top of which presses against a pressure-contact portion of a sealed body, and A slot is formed at a predetermined position on one of the pressing surface and the receiving surface, into which the clamped portion of the object to be sealed is pressed, and a clamping protrusion is formed on the other surface, which presses the clamped portion into the slot to clamp the object to be sealed, When the actuator moves the horn connected to the vibration unit toward the anvil, the clamped portion is clamped between the slot and the clamping ridge to fix the sealed object between the pressing surface and the receiving surface, and the pressing surface is pressed toward the receiving surface, and at the same time, the ultrasonic oscillator oscillates with a predetermined main ultrasonic vibration, and main vibration energy related to the main ultrasonic vibration is applied to the horn, an ultrasonic sealing device in which the pressure-welded portion pressed by the sealing ridge is welded at a predetermined sealing temperature by frictional heat associated with the main vibration energy, and the sealing ridge sinks a predetermined amount into the pressure-welded portion melted by the frictional heat, thereby linearly sealing the pressure-welded portion along the sealing ridge, When the vibration sensor detects a main vibration frequency of the main ultrasonic vibration and outputs a main frequency signal based on the main vibration frequency to the control unit, the control unit determines a total amount of applied heat from the input start time of the main frequency signal to a predetermined detection time with respect to the applied heat based on the main vibration energy, and determines a total amount of excess heat from the input start time to the detection time with respect to excess heat obtained by subtracting the welding heat consumed in the work related to the previous welding between the sealing ridge and the pressing surface from the frictional heat, and calculates an energy deficiency that is insufficient for the work related to the subsequent welding at the detection time by subtracting the total amount of excess heat from the total amount of applied heat; calculating an environmental temperature in the vicinity of the horn and the anvil based on the accumulated heat in the horn and the anvil at the detection time by subtracting a predetermined amount of heat radiation from the excess heat; a vibration control signal relating to the subordinate ultrasonic vibration is output to the vibration unit in order to compensate for the energy obtained by subtracting the stored energy relating to the heat storage from the deficient energy with the subordinate ultrasonic vibration output from the ultrasonic oscillator; outputting a position control signal to the actuator to move the horn having the pressing surface toward and away from a predetermined position relative to the pressure-welded portion that is melted by secondary vibration energy related to the secondary ultrasonic vibration and the environmental temperature; the actuator controls the position of the vibration unit based on the position control signal to adjust the amount of depression of the sealing protrusion with respect to the pressure-welded portion; The vibration unit oscillates the ultrasonic oscillator based on the vibration control signal to output the secondary ultrasonic vibration, an ultrasonic sealing device characterized in that the ultrasonic oscillator adjusts the secondary vibration energy applied to the pressure-welded portion by the secondary ultrasonic vibration in response to rises and falls in the environmental temperature, and the actuator adjusts the position of the vibration unit so that the amount of sinking of the sealing protrusion into the pressure-welded portion, which melts due to the secondary vibration energy and the environmental temperature, is kept constant within a predetermined range, thereby sealing the pressure-welded portion.

2. 2. The ultrasonic sealing device according to claim 1, wherein the sinking amount is 10 μm to 200 μm.

3. 3. The ultrasonic sealing device according to claim 2, wherein when the pressure-welded portion is made of a synthetic resin material for retort pouches, the sinking amount is 60 μm to 75 μm.

4. 2. The ultrasonic sealing device according to claim 1, wherein the energy deficiency at the predetermined detection time is substantially constant from the input start time.

5. 2. The ultrasonic sealing device according to claim 1, wherein the object to be sealed is a packaging bag having a predetermined heat-sealable film at least at the opening of the bag.

6. 2. The ultrasonic sealing device according to claim 1, wherein the object to be sealed is a packaging container that can be covered by welding a predetermined heat-sealable film to the periphery of the container.

7. a horn having a pressing surface that transmits predetermined ultrasonic vibrations; an anvil having a receiving surface disposed opposite the pressing surface of the horn; a vibration unit having an ultrasonic oscillator that oscillates the ultrasonic vibration at a predetermined vibration frequency and an output shaft that outputs the ultrasonic vibration from the ultrasonic oscillator, the horn being connected to a tip of the output shaft; an actuator that holds the vibration unit so as to be freely movable toward and away from the anvil, and presses the pressing surface toward the receiving surface with a predetermined pressure when the horn connected to the vibration unit is brought close to the anvil; a vibration sensor that detects the vibration frequency of the ultrasonic oscillator; a control unit that controls the operation of both or either one of the vibration unit and the actuator based on the vibration frequency detected by the vibration sensor, A seal protrusion is formed at a predetermined position on either the pressing surface or the receiving surface, the top of which presses against a pressure-contact portion of a sealed body, and In an ultrasonic sealing device, a slot into which a clamped portion of the object to be sealed is pressed is formed at a predetermined position on one of the pressing surface and the receiving surface, and a clamping protrusion is formed on the other surface to clamp the object to be sealed by pressing the clamped portion into the slot, a pressing step in which the actuator moves the horn connected to the vibration unit toward the anvil, clamping the clamped portion between the slot and the clamping ridge to fix the sealed object between the pressing surface and the receiving surface, and pressing the pressing surface toward the receiving surface to press the pressure-welded portion between the sealing ridge and the pressing surface; When the ultrasonic oscillator oscillates with a predetermined main ultrasonic vibration and the main vibration energy related to the main ultrasonic vibration is applied to the horn, a control method for an ultrasonic sealing device including a welding process in which the horn performs a process of welding the pressure-welded portion, which is pressure-welded by the sealing protrusion, at a predetermined sealing temperature by frictional heat associated with the primary vibration energy, a vibration frequency output process in which the vibration sensor detects a main vibration frequency associated with the main ultrasonic vibration and outputs a main frequency signal based on the main vibration frequency to the control unit; a total applied heat amount calculation step in which the control unit performs processing to calculate a total applied heat amount from an input start time of the main frequency signal to a predetermined detection time, with respect to the applied heat based on the main vibration energy; a total excess heat calculation step in which the control unit performs processing to calculate a total excess heat amount from the input start time to the detection time, with respect to excess heat obtained by subtracting welding heat consumed in work related to previous welding between the sealing ridge and the pressing surface from the frictional heat during the welding step between the horn and the anvil; a deficit energy calculation step in which the control unit calculates a deficit energy required for subsequent welding work at the detection time by subtracting the total surplus heat amount from the total applied heat amount, In parallel with both or either one of the pressure welding step and the welding step, an environmental temperature calculation step in which the control unit calculates an environmental temperature in the vicinity of the horn and the anvil based on the accumulated heat stored in the horn and the anvil at the detection time by subtracting a predetermined amount of heat radiation from the excess heat; a vibration control step in which the control unit outputs a vibration control signal relating to the subordinate ultrasonic vibration to the vibration unit unit in order to compensate for the energy obtained by subtracting the accumulated energy relating to the heat storage from the energy deficiency with the subordinate ultrasonic vibration output from the ultrasonic oscillator; a position control step in which the control unit outputs a position control signal to the actuator to move the horn having the pressing surface toward and away from a predetermined position relative to the pressure-welded portion that is melted by secondary vibration energy related to the secondary ultrasonic vibration and the environmental temperature, a pressing control process is provided in which the actuator controls the position of the vibration unit based on the position control signal to adjust the amount of depression of the sealing protrusion into the pressure-welded portion, in relation to the pressing process; a welding control step for causing the vibration unit to oscillate the ultrasonic oscillator based on the vibration control signal and outputting the slave ultrasonic vibration, A control method for an ultrasonic sealing device, characterized in that the ultrasonic oscillator adjusts the secondary vibration energy that it applies to the pressure-welded portion by the secondary ultrasonic vibration in response to rises and falls in the environmental temperature, and the actuator adjusts the position of the vibration unit so that the amount of sinking of the sealing protrusion into the pressure-welded portion, which melts due to the secondary vibration energy and the environmental temperature, is kept constant within a predetermined range, thereby sealing the pressure-welded portion.

8. The method for controlling an ultrasonic sealing device according to claim 7, wherein the sinking amount is 10 μm to 200 μm.

9. 8. The method for controlling an ultrasonic sealing device according to claim 7, wherein the sinking amount is 60 μm to 75 μm when the pressure-welded portion is made of a synthetic resin material for retort pouches.

10. 8. The method for controlling an ultrasonic sealing device according to claim 7, wherein the energy deficiency at the predetermined detection time is substantially constant from the input start time.

11. 8. The method for controlling an ultrasonic sealing device according to claim 7, wherein the object to be sealed is a packaging bag having a predetermined heat-sealable film at least on the opening of the bag.

12. 8. The method for controlling an ultrasonic sealing device according to claim 7, wherein the object to be sealed is a packaging container that can be covered by welding a predetermined heat-sealable film to the periphery of the container.

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