JPH1022067A - Electromagnetic induction heating type binding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable heating by an electromagnetic induction heating device for bookbinding to be controlled to a certain temperature through simple control. SOLUTION: This device includes a high frequency generated means 22, heating coils 30a to 30d to which high frequency outputs of the high frequency generation means 22 are applied, and a control means 24 for the high frequency outputs which the high frequency generation means 22 produces, and the high frequency outputs are lowered under the control of the control means 24 after the elapse of a predetermined time since the start of induction heating by the coils 30a to 30d used for heating a metallic conductor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bookbinding apparatus that binds paper or the like with a cover and binds the book easily, and more particularly to a bookbinding apparatus that melts an adhesive by electromagnetic induction heating to bind a book.

[0002]

2. Description of the Related Art Conventionally, a bookbinding apparatus having a principle shown in FIGS. 8 and 9 has been developed as a bookbinding apparatus for simply binding a plurality of sheets of paper with a cover. That is, FIG. 8 is a diagram showing a configuration of the cover, and the cover 1 includes a front door 1a, a rear door 1b,
a, 1b (spine), which joins a and 1b,
A hot-melt adhesive 2 is applied to the inner surface of the bottom 1c. Then, the adhesive 2 is melted by heat, and the end face of the book 3 such as a plurality of sheets of paper is adhered to the cover 1,
Book binding.

[0003] In this case, as a heat source for melting the adhesive 2, a heater such as a heating wire has conventionally been used. That is, for example, as shown in FIG. 9, the heating wire 4 is brought close to the bottom of the cover 1, the adhesive 2 is heated and melted by the heating wire 4, and the end face of the book 3 is bonded to the bottom of the cover 1. Was like that.

However, in the case of such a bookbinding apparatus in which heating is performed by a heater, the cover itself is heated, so that there is a disadvantage that a resin material that can be melted by heating cannot be used as the cover. Further, when a cover made of paper is used, there is an inconvenience that the paper as the cover is burned and discolored by heating.

In order to solve these problems, it has been proposed to apply an electromagnetic induction heating device to a bookbinding device. In this bookbinding apparatus, as shown in FIG. 10, for example, as a cover 1, a metal sheet 5 is adhered to the inner surface of the bottom of the cover 1, and a hot-melt adhesive 6 (epoxy adhesive or the like) is placed on the metal sheet 5. ) Is used.

[0006] Then, heating is performed using an electromagnetic induction heating device that is put into practical use for cooking utensils and the like. That is, the metal sheet 5 and the adhesive 6 thereon are heated using the heating coil 14 (work coil) of the electromagnetic induction heating device. In this case, a high-frequency current is applied to the heating coil 14.

FIG. 11 shows a configuration for applying a high-frequency current to the heating coil 14. In FIG. 11, reference numeral 11 denotes a commercial AC power supply, and a 100 V AC signal obtained from the power supply 11 is rectified by a diode bridge. The DC signal is supplied to the circuit 12 and full-wave rectified. The + side of the rectified signal output portion of the rectifier circuit 12 is connected to one end of a heating coil 14 via a filter choke coil 13, and the other end of the heating coil 14 is connected to an output transistor (NPN transistor). ) Connect to 17 collectors,
The emitter of the output transistor 17 is connected to the minus side of the rectified signal output section of the rectifier circuit 12.

Then, a resonance capacitor 15 is connected to the heating coil 14 in parallel. A damper diode 16 is connected between the emitter and the collector of the output transistor 17. A filter capacitor 1 is provided between the + side and the − side of the rectified signal output section of the rectifier circuit 12.
8 is connected. Further, the filter choke coil 13
The filter capacitor 1 is connected between a connection point of the rectifier circuit 12 and the heating coil 14 and a negative side of the rectified signal output unit of the rectifier circuit 12.
9 is connected.

The output of the drive circuit 23 is supplied to the base of the output transistor 17. in this case,
An oscillating circuit 22 generates an oscillating signal having a frequency of several tens of kHz using a DC low-voltage signal obtained by converting the commercial AC power supply 11 by a power supply circuit 21 as a power supply.
To a drive signal for driving the transistor 17. When the drive signal having a frequency of about several tens of kHz is supplied to the base of the output transistor 17, the rectified signal output from the rectifier circuit 12 is switched in synchronization with the frequency of the control signal, and the heating coil 1 is switched.
A high-frequency current flows through 4.

When the high-frequency current flows through the heating coil 14 in this manner, magnetic lines of force are generated from the surface of the heating coil 14. By arranging the metal sheet 5 as an object to be heated in the alternating magnetic field where the lines of magnetic force reach (that is, in the vicinity of the heating coil 14), a closed loop current (eddy current) is generated in the metal sheet 5 by an electromagnetic induction phenomenon. ) Flows, and Joule heat (eddy current loss) generated by the eddy current and the conductor resistance of the metal sheet 5 heats the metal sheet 5 itself.

By using such an electromagnetic induction heating device as a bookbinding device, it is possible to heat only the metal sheet 5 inside the cover 1 and the adhesive 6 thereon as shown in FIG. , A material having low heat resistance can be used.

[0012]

By the way, there are various sizes of covers used for bookbinding with a bookbinding apparatus. When the above-mentioned electromagnetic induction heating apparatus is used as a bookbinding apparatus, it is used. It is necessary to control the heating time and the like according to the size of the cover 1. That is, if the heating is performed more than necessary, the temperature of the cover and the book becomes high, which may damage the cover and the book, and the adhesive is heated to a predetermined temperature at which the adhesive is melted. Must not be heated.

However, in a conventional electromagnetic induction heating device,
Strict temperature control required for the bookbinding apparatus has been difficult. That is, when the electromagnetic induction heating device is used as a bookbinding device, the metal sheet inside the cover, which is the object to be heated, has a width of several mm to several cm and is very small,
It is difficult to control the temperature to be exactly constant by heating for a short time of about several seconds (that is, by heating with large electric power).
There is a disadvantage that the heating temperature becomes non-uniform.

In view of the above, an object of the present invention is to enable heating for bookbinding by an electromagnetic induction heating device to be controlled to a constant temperature by a simple control.

[0015]

According to the present invention, there is provided a control means for controlling a high-frequency output generated by a high-frequency generating means. It is intended to be.

According to such a configuration, until a predetermined time elapses from the start of heating, heating is performed at a relatively high high-frequency output to a certain temperature in a short time, and thereafter, strict heating to a target temperature is performed by the reduced high-frequency output. Adjustment to make it possible.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will now be described with reference to FIGS.
This will be described with reference to FIG. In FIGS. 1 to 7, parts corresponding to those in FIG. 8 and subsequent figures are given the same reference numerals, and detailed description thereof will be omitted.

In this embodiment, an electromagnetic induction heating device configured as a bookbinding device is used.
As in the case of the cover 1 described above, a metal sheet 5 is attached to the inner surface of the spine, and bookbinding is performed using the cover 1 in which a hot-melt adhesive 6 is applied on the metal sheet 5. In this example, the metal sheet 5 has a thickness of 20 μm.
An aluminum foil of about 30 μm is used. In this example, four coils 30a and 30 are used as heating coils.
First, a configuration of a bookbinding apparatus using four heating coils 30a to 30d will be described with reference to FIGS. 3 and 4. FIG.

FIG. 3 is a diagram showing a cross section of the bookbinding apparatus, in which heating coils 30a to 30d are arranged close to the spine of the book 3 sandwiched between the covers 1, and FIG. As shown, four are arranged linearly along the length direction of the spine. And each heating coil 30a-30d of this example
Is formed by bonding a rod-shaped circular core 32 of a predetermined height to the center of a circular and flat core 31 and winding a winding 33 around the core 32. Is made equal to or smaller than the diameter of the circular core 31. However, as shown by arrows in FIG. 3, the winding directions of the windings of the heating coils 30a and 30c and the heating coil 30
The winding directions of the windings b and 30d are opposite to each other, and are arranged so that the winding direction changes for each winding.

The four heating coils 30a to 30d
Are arranged on a substrate 41, and the four heating coils 3
Bottom plate 4 that abuts the spine of cover on 0a-30d
2 (non-magnetic material) are arranged, and two pressing plates 43 and 44 are arranged perpendicularly to the bottom plate 42 in a state where the interval can be adjusted. These members are integrally housed in a housing 45, and between the two pressing plates 43, 44 from the top of the housing 45, the book product 3 sandwiched by the cover 1.
Can be inserted.

After the book material 3 sandwiched between the covers 1 is inserted between the two holding plates 43 and 44, the two holding plates 43 and 44 are inserted into the two holding plates 43 and 44 by arrows a and b in FIG. Heat is applied by applying a force in the direction shown to start applying a high-frequency current to the four heating coils 30a to 30d while holding the book 3 sandwiched between the covers 1.

Next, the configuration of a drive circuit for the four heating coils 30a to 30d in the bookbinding apparatus configured as described above will be described. FIG. 1 is a diagram showing the circuit configuration.
The heating coils 30a, 30b, 30c, 30d are connected in series. That is, the + side of the rectification signal output section of the rectification circuit 12 is connected to one end of the heating coil 30a via the filter choke coil 13, and the heating coil 30a
Is connected to one end of the next-stage heating coil 30b,
The other ends of the heating coil 30c at the final stage are connected to the collector of the output transistor 17 in the following order. The four heating coils 30a, 30 connected in series
The resonance capacitor 15 is connected in parallel with b, 30c, and 30d.

In this embodiment, a load current detecting resistor 20 is connected between the emitter of the output transistor 17 and the rectifier circuit 12, and the output of the resistor 20 is detected by the load detecting circuit 25. By detecting the output current of the resistor 20 with the load detection circuit 25, the width of the metal sheet 5 disposed above the heating coils 30a to 30d as a load can be detected. FIG. 5 is a diagram showing the correspondence between the detection output (voltage value or the like) of the additional detection circuit 25 and the width of the object to be heated (metal sheet 5). In this example, the detection output is the width of the metal sheet. It can be seen that it is proportional to

The data of the load current detected by the load detection circuit 25 is supplied to the control circuit 24.
The power of the oscillation output of the oscillation circuit 22 is controlled by the control circuit 24. Then, the oscillation output of the oscillation circuit 22 is supplied to the drive circuit 23 to be a drive signal for driving the transistor 17, and the frequency of the drive signal (for example, about 20 k
The transistor 17 is switched in synchronization with a constant frequency within a range of about 30 kHz to about 30 kHz, and a high-frequency current flows through the heating coil 14.

The control circuit 24 performs processing for controlling the power of the oscillation output of the oscillation circuit 22 based on the width of the load detected by the load detection circuit 23. Here, the configuration of the control circuit 24 will be described with reference to FIG. 2. The control circuit 24 includes an oscillation control unit 24a, a power down circuit 24b, and a timer circuit 24c. Detection data is provided. When determining the width of the load based on the detection data of the load detection circuit 23, the oscillation control unit 24a sets the power of the oscillation output based on the width. Then, the timer circuit 24c counts the lapse of time from the start of the heating by setting the power, and when the time corresponding to the determined load width has elapsed, the oscillation control unit 24c.
a is instructed to lower the power, and when the time corresponding to the heating stop from the start of heating (the time also set according to the determined load width) has elapsed from the start of heating, the heating stop is notified to the oscillation control unit 24a. To instruct. Then, the power-down circuit 24b instructs the oscillation control unit 24a of the power at the time of power reduction corresponding to the determined load width.

When the power down is instructed by the timer circuit 24c, the oscillation control unit 24a
Control is performed to reduce the oscillation output to the power instructed by the power down circuit 24b, and further, when heating stop is instructed by an instruction from the timer circuit 24c, the oscillation output from the oscillation circuit 22 is stopped.

The other parts are configured in the same manner as the conventional circuit shown in FIG.

Next, the operation of the electromagnetic induction heating apparatus of this embodiment when performing heating for bookbinding will be described. When heating is performed by the apparatus of this embodiment, control is performed as shown in FIG.
That is, the oscillation circuit 22 is turned on to output an oscillation signal, and at the same time, the width of the load is detected, and the input power P ₁ corresponding to the width is immediately set, and the input power P ₁ is set.
The heating of the metal sheet 5 by ₁ is started. When the start of heating the predetermined time T ₁ is passed, the power down instruction from the timer circuit 24c is indicated, control is performed to power down the input power P _2, which is indicated by the power-down circuit 24b. When the predetermined time T ₂ has elapsed from the start of heating, the heating stops at an instruction from the timer circuit 24c is indicated, the oscillation circuit 22 is turned off,
Control for stopping the oscillation output is performed.

Here, the input power P ₁ at the start, which is set by the width of the metal sheet 5 made of aluminum foil, which is a load in the case of this embodiment, and the input power P ₂ after the power down.
When a time T ₁ of the start of heating until a power-down, an example of a heating time T ₂ of the total to the heating stop start of heating, in the following table.

[0030]

[Table 1]

The example of Table 1 shows that the total heating time T ₂
Is constant irrespective of the change in the width of the metal sheet 5 (10
Second).

As described above, by performing power-down after a predetermined time from the start of heating, it becomes possible to control the heating temperature of the metal sheet 5 to be heated very accurately. This will be described with reference to FIG. FIG. 7 compares the temperature change A of the metal sheet 5 when the heating is performed with a constant power from the start of the heating and the temperature change B of the metal sheet 5 when the power is reduced a predetermined time after the start of the heating as in this example. FIG. In this example, the input power P ₁ at the start is
, Both characteristics A, B has a 500 W, in the case of characteristic B performs power down timing t _X 5 seconds after the start of heating, there subsequent input power P ₂ as 250 W.

[0033] In the case of heating characteristics A constant input power P ₁ is almost temperature rises sharply at a constant rate, reaching at timing t _A is the optimum temperature T ₀ of the target, In the case of the power-down characteristic B, the timing t
The temperature change after the power-down becomes small in _X, the optimum temperature T ₀ of the target is reached at time t _B.

Here, assuming that the change in temperature is ΔT and the change in time is Δt, the ratio of the temperature rise [ΔT / Δt] in the vicinity of the target temperature T ₀ between the characteristics A and B is as follows. It can be seen from FIG. 7 that there is a great difference. That is, assuming that the temperature rise ratio [ΔT / Δt] near the optimum temperature T ₀ in the characteristic B of the present example in which power down is performed is 1, the vicinity of the optimum temperature T ₀ in the conventional characteristic A without power down is assumed. Of the temperature rise [ΔT / Δt] is about 4 to 5.
Here, when the allowable heating temperature error is ± 3 ° C.,
In the case of the characteristic B of this example, the control of the heating time is, for example, ±
With the accuracy of 1.5 seconds, it is possible to set the temperature within this error range. In contrast, in the case of the conventional characteristic A, in order to set the temperature within the same error range, the heating time must be controlled. ±
It must be performed with an accuracy of 0.3 seconds.

Therefore, by performing the control of the present embodiment, if it is assumed that the accuracy of, for example, the load detection in the driving circuit of the heating coil is the same as the conventional one, the variation in the heating temperature can be reduced to about the conventional level. The heating temperature can be reduced to about 1/5, and the heating temperature can be accurately controlled accordingly.

In the experiment, the input power P ₁ at the start of heating was used.
And the ratio of input power P ₂ after power down to 0.1
It was confirmed that good control was possible by setting the range of ≦ (P ₂ / P ₁ ) ≦ 0.9.

In the above embodiment, the power down is set to 1
Although the power is reduced only once, the power may be reduced a plurality of times during one heating to gradually reduce the power. Also, instead of being immediately reduced to P ₂ to the input power from P ₁ in power-down, as shown in FIG. 6, it may be decreasing gradually with some time constant.

The heating time described above is an example, and varies depending on the configuration of the cover (ie, the material of the metal sheet, the temperature at which the adhesive melts, etc.). If the materials of the sheet and the adhesive are completely different, it is necessary to change the settings of the input power and the heating time.

In the above-described embodiment, the configuration for detecting the width of the load by the load detection circuit 25 is not particularly described. However, various types of current detection circuits can be applied. Alternatively, instead of detecting from such electric characteristics, the width of the loaded cover may be directly detected by some method.

[0040]

According to the present invention, until a predetermined time elapses from the start of heating, heating is performed at a relatively high high-frequency output to a certain temperature in a short time, and thereafter, the temperature is reduced to a target temperature by a reduced high-frequency output. This makes it possible to achieve both heating in a short time and control of the heating temperature, thereby enabling bookbinding of a constant quality in a short time.

In this case, by changing the ratio of the time from the start of induction heating to the decrease in high-frequency output to the time from the start of induction heating to the stop of induction heating according to the width of the metal conductor detected by the width detection means, Appropriate output management according to the binding width can be performed, and even when the binding width changes, accurate heating to a constant temperature can be performed at all times.

Further, according to the width of the metal conductor detected by the width detecting means, the ratio of the input power of the high frequency generating means after the high frequency output is reduced to the input power of the high frequency generating means at the start of the induction heating is changed. This also makes it possible to control output appropriately in accordance with the width of bookbinding, so that even when the width of bookbinding changes, accurate heating to a constant temperature can be performed at all times.

The input power P ₂ after the output is reduced with respect to the input power P ₁ before the high frequency output is reduced by 0.1 ≦ (P ₂ /
By setting P ₁ ) ≦ 0.9, good control can be achieved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a control circuit of one embodiment.

FIG. 3 is a sectional view of a bookbinding apparatus according to one embodiment.

FIG. 4 is a side view showing an arrangement state of a heating coil of the bookbinding apparatus according to one embodiment.

FIG. 5 is a characteristic diagram showing a load detection state according to one embodiment.

FIG. 6 is a characteristic diagram showing an example of power control according to one embodiment.

FIG. 7 is a characteristic diagram showing an example of a temperature change according to one embodiment.

FIG. 8 is a perspective view illustrating a configuration of a cover used in the bookbinding apparatus.

FIG. 9 is an explanatory diagram showing an example of a conventional bookbinding apparatus.

FIG. 10 is an explanatory diagram showing an example of a bookbinding device using an electromagnetic induction heating device.

FIG. 11 is a circuit diagram showing an example of a drive circuit of a conventional electromagnetic induction heating device.

[Explanation of symbols]

1 Cover, 3 genuine product, 5 metal sheet, 6 hot-melt adhesive, 17 output transistor, 22 oscillation circuit, 23 drive circuit, 24 control circuit, 2
5. Load detection circuit, 30a, 30b, 30c, 30d
Heating coil, 31, 32 cores, 33 windings

Claims (4)

[Claims] 1. A high-frequency generating means, and a heating coil to which a high-frequency output of the high-frequency generating means is applied, wherein a band-shaped metal conductor arranged near the heating coil is removed from the heating coil. In the electromagnetic induction heating type bookbinding apparatus, which is heated by the generated magnetic force lines and adheres a book to be bound by melting a hot-melt adhesive disposed in the vicinity of the metal conductor, the high frequency generated by the high frequency generating means An electromagnetic induction heating type bookbinding device comprising output control means, wherein the high frequency output is reduced after a predetermined time has elapsed from the start of induction heating of the metal conductor under the control of the control means. 2. The apparatus according to claim 1, further comprising a width detecting means for detecting the width of the metal conductor, the time from the start of induction heating to the stop of induction heating, and The electromagnetic induction heating type bookbinding apparatus according to claim 1, wherein the ratio is changed. 3. The high-frequency generating means after the high-frequency output decreases with respect to the input power of the high-frequency generating means at the start of induction heating, according to the width detected by the width detecting means. 2. The electromagnetic induction heating type bookbinding device according to claim 1, wherein the input power ratio is changed. 4. The input power P ₂ after the output is reduced with respect to the input power P ₁ before the high frequency output is reduced by 0.1 ≦ (P ₂ /
2. The electromagnetic induction heating type bookbinding device according to claim _{1, wherein} P1) ≦ 0.9.