JPH04339735A - Controlling method for heater of packing machine setting optimum heat sealing temperature corresponding to variation of ambient temperature - Google Patents

Abstract

PURPOSE:To make a uniform heat sealing constantly under an optimum heat sealing temperature by correcting automatically heat sealing conditions of packing paper which depends delicately on variation of environmental temperature. CONSTITUTION:In a packing machine which makes heat sealing of packing paper by temperature control of a heater, a temperature set value of a heater used for the heat sealing is corrected corresponding to a difference between a preset reference temperature and an environmental one. In this instance, the temperature set value of the heater at the reference temperature is corrected according to a temperature sloping of the packing paper in use which corresponds to the temperature difference.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is a packaging machine that sets the optimum heat sealing temperature in response to changes in ambient temperature so that a good adhesion state can always be obtained even if there is a change in the ambient temperature of the packaging machine. The present invention relates to a heater control method.

0002

2. Description of the Related Art A heat sealing method using a heater is generally widely used as a method for bonding wrapping paper in automatic packaging machines. This is because the bonding method using heat sealing has the advantage that bags can be made even from strip-shaped films and that high-speed processing can be easily achieved.

The temperature settings for heat sealing vary depending on the heat capacity of the material to be packaged, the melting point of the adhesive, etc., but packaging machines are generally constructed so that these conditions can be set arbitrarily.

Furthermore, in order to obtain the same bonding conditions, it is sufficient to apply the same thermal load to the wrapping paper, so even if the wrapping paper has the same conditions, the temperature setting value will differ depending on the heating time applied to the wrapping paper.

[0005] For this reason, packaging machines have appeared that automatically control the heater temperature setting according to the number of rotations of the wrapping paper, that is, the packaging processing speed.

[0006] This involves searching for a temperature setting point at which good adhesion can be obtained at the core rotational speed while testing the wrapping paper to be used, and if a good setting point is found, stopping the machine. Then, set and register the rotation speed and temperature data at that time.

[0007] By sequentially registering this in the range of the rotational speed actually used, the temperature setting of the heater is automatically changed according to the film speed, and heat sealing is always performed with good adhesion.

[0008]

However, the temperature setting conditions of the heater for obtaining good heat sealing conditions depend not only on the rotational speed of the packaging machine but also on the environmental temperature surrounding the packaging machine. This is because this change in ambient temperature results in a change in the temperature of the packaging material such as a film, and also changes the amount of heat dissipated from the heater, which is accompanied by a change in the heat load of the heater. especially,
In high-speed packaging machines, the time that the film to be heat-sealed is in contact with the heater is only a short time, so it is severely influenced by the temperature setting value of the heater.

There is no problem if the packaging machine is installed in a temperature-controlled location, but packaging machines are generally set up for finishing processes, and are used to transport packaging materials and products after packaging is completed. Currently, the temperature is not regulated as this is done frequently.

[0010]Therefore, the ambient temperature of the packaging machine was different in summer and winter, and even in the morning and afternoon on the same day.

[0011] For this reason, in conventional packaging machines, no measures were taken against this ambient temperature change, so the temperature was adjusted manually based on the operator's experience while observing the packaging condition. I was going. As a result, defective packaging products were produced due to incorrect temperature settings at the start. The present invention was developed in view of the problems of the prior art described above, and it is possible to heat-seal wrapping paper in a good adhesive state at all times, regardless of temperature changes around the packaging machine. It is an object of the present invention to provide a method for controlling a heater for a packaging machine, which sets an optimal temperature for heat sealing according to changes in ambient temperature.

0012

[Means for Solving the Problems] The above object is to provide a packaging machine that heat-seals wrapping paper by controlling the temperature of a heater, so that the temperature setting value of the heater is adjusted to the difference between a predetermined reference temperature and the ambient temperature. This is achieved by a method of controlling a heater for a packaging machine that sets an optimum heat sealing temperature in response to a change in ambient temperature, which is characterized in that the heater temperature set value at the reference temperature is corrected by a value corresponding to the difference based on the above.

[0013]

[Operation] That is, in this method of controlling the heater of the packaging machine, the set temperature of the heater is changed by a value corresponding to the difference between a predetermined reference temperature and the ambient temperature during machine operation. As a result, when the ambient temperature drops and the heat load on the heater increases, such as in winter, the temperature of the packaging material will naturally also be cold, so the set temperature of the heater should be increased in advance according to the temperature gradient based on experimental values. .

[0014] Accordingly, since changes in the ambient temperature of the packaging machine are automatically read and the set temperature of the heater is automatically corrected, it is possible to always perform heat sealing in a good adhesion state.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a main block diagram showing only a temperature setting section for optimal heat sealing according to changes in ambient temperature of an automatic packaging machine according to the present invention, and FIG. 2 is a flowchart thereof.

In FIG. 1, 1 is a heater temperature setting panel for inputting the heater temperature setting value, etc., and when changing the heater temperature setting value at the standard temperature corresponding to the packaging material used, and the environmental temperature of the packaging machine. Corrected gradient data for heater set temperature (
The temperature difference, heater temperature set value), etc. are input.

[0018] Since this block diagram only shows the parts related to the gist of the present invention, it is naturally possible to input the rotation speed of the packaging machine and the heater temperature setting value at that time, etc., which has been done conventionally. However, it is omitted because it complicates the drawing.

The data input through the heater temperature setting panel 1 is registered in the heater temperature registration section 6 of the memory section.

Reference numeral 2 denotes an environmental temperature measuring device for measuring the environmental temperature in which the packaging machine is set, and is composed of a thermistor or a thermocouple.

4 is a heater temperature setting based on the temperature difference between the value measured by the environmental temperature measuring device 2 and the reference temperature value for the wrapping paper in use, which is registered in the heater temperature registration section 6. A temperature difference comparison calculation unit 4 that calculates the value calculates a heater temperature setting value that matches the environmental temperature.

That is, in this calculation section 4, the heater temperature setting value is corrected for each type of wrapping paper and for each rotational speed of the packaging machine at that time, and also for changes in the environmental temperature around the packaging machine. Formula (a = (20-b) x c, a: set temperature correction value, 20: environmental standard temperature, b: environmental temperature measurement value, c: wrapping paper coefficient) or the corrected heater temperature for each temperature difference in the memory table. Since the set values are registered, comparison calculations are performed based on these registered data.

Reference numeral 5 denotes a temperature setting section which sets the heater temperature setting value calculated by the temperature difference comparison calculation section 4 as a target value in the heater temperature controller 7.

Thereafter, based on the value of the temperature setting section 5 that has been corrected to suit the environmental temperature, the heater temperature controller 7, heater 8, and temperature sensor 9, which is normal closed loop control, keep the heater 8 at a constant level. The temperature is controlled.

Although only one heater 8 is shown in the figure, the temperature comparison calculation section 4, temperature setting section 5, and temperature sensor 9 described above are used in proportion to the number of heaters used. It is sufficient to set

[0026] Normally, the calculation section other than the temperature sensor 9 is as follows:
Since it is configured by a sequencer or microcomputer program, it can be configured by software without increasing the number of parts. Reference numeral 10 denotes a heater temperature display section which converts the voltage value or resistance value detected by the temperature sensor 9 into temperature and displays the converted temperature.

The control block diagram according to the present invention is constructed as described above. Next, its operation will be explained based on the flowchart of FIG. This figure 2 shows when the ambient temperature of the packaging machine differs from the standard temperature (usually set at 20°C) when the control temperature of the heater is set according to the wrapping paper used and the rotation speed of the packaging machine. This figure shows a flowchart for correcting the heater set temperature when the environmental temperature of the packaging machine is constantly measured by the environmental temperature measuring device 2.
(F1), calculate the temperature difference between this temperature value and a predetermined reference temperature (F2), and use this temperature difference to correct the heater setting temperature of the wrapping paper being used (see above). ) to calculate the optimum heat sealing temperature setting (F3). Then, the set value of the heater temperature is calculated based on this value (F4).

As described above, the heat sealing conditions for wrapping paper are adjusted so that the heater temperature setting value is corrected not only for the rotation speed of the packaging machine but also for the environmental temperature in which the packaging machine is installed. Therefore, even if the temperature of the object to be adhered changes and the heat load fluctuates due to changes in the air temperature, the heater temperature is controlled in accordance with this change, so that heat sealing can always be performed in a uniform state.

[0029] As a result, the occurrence of defective packages that conventionally occur while searching for the set temperature of the heater has been eliminated.

[0030]The temperature setting of the heater is most influenced by the temperature of the wrapping paper to be heat-sealed, so it is sufficient to measure the surface temperature of the wrapping paper, but in general, the surface temperature of the wrapping paper is equal to the environmental temperature. Therefore, the set temperature of the heater can be determined based on the measured value of the environmental temperature. The measuring device 2 that measures the environmental temperature needs to be installed at a location that is not affected by heat generated by machine operation.

[0031]

Effects of the Invention As described above, the present invention corrects the heat seal setting temperature of the heater of the packaging machine while always taking in the environmental temperature where the packaging machine is installed, so that the heat seal is always optimal. Wrapping paper can be heat-sealed under certain conditions.

In particular, in high-speed packaging machines, the time the wrapping paper is in contact with the heater is short, and the quality of adhesion is severely affected by the temperature setting of this heater. By incorporating the control method according to the invention, uniform heat sealing can be carried out automatically and always under good conditions.

[Brief explanation of drawings]

FIG. 1 is a heater control block diagram of an embodiment.

FIG. 2 shows a flowchart of an embodiment.

[Explanation of symbols]

1 Heater temperature setting panel 2 Environmental temperature measuring device 4 Temperature difference comparison calculation section 5 Temperature setting section 7 Heater temperature controller 8 Heater 9 Temperature sensor

Claims (1)

[Claims] Claim 1: In a packaging machine that heat-seals wrapping paper by controlling the temperature of a heater, the temperature setting value of the heater is set at a reference temperature based on the difference between a predetermined reference temperature and an ambient temperature. A method for controlling a heater for a packaging machine that sets an optimum heat sealing temperature in response to a change in ambient temperature, the method comprising modifying a value in accordance with the difference.