JP5514512B2 - Magnetic field generator, heating device, and image forming apparatus - Google Patents

Description

  The present invention relates to a magnetic field generator, a heating device, and an image forming apparatus.

  The heating device described in Patent Document 1 causes the resonance circuit to perform a resonance operation by supplying a pulsed current generated by the switching element to the resonance circuit including a capacitor and an excitation coil. As a result, a magnetic field whose current value and direction change according to the resonance frequency is generated in the exciting coil, and an eddy current is generated in the heated object. Then, Joule heat is generated in the heated body by the eddy current generated in the heated body. Thereby, a to-be-heated body is heated.

  In this heating apparatus, the temperature of the object to be heated is adjusted by adjusting the ON duty width of the pulsed current supplied to the resonance circuit. And this heating apparatus prevents that a to-be-heated body is heated too much by stopping supply of the pulse-form electric current to a resonance circuit, when the ON duty width | variety of a pulse-form electric current becomes large too much.

  FIG. 9 is a diagram showing a magnetic field generator used in the heating device disclosed in Patent Document 1. In the magnetic field generator 100 shown in FIG. 9, a series circuit including a switching element 2 that generates a pulsed current and an LC resonance circuit including a capacitor 21 and an exciting coil 300 is connected to the power line L. A current path 200 is provided between the capacitor 21 and the exciting coil 300. The connector 400 connects the current path 200 on the capacitor 21 side and the current path 200 on the exciting coil 300 side.

  In the magnetic field generation device 100, the switching element 2 includes a transistor 20. In the figure, a diode 22 is a diode through which a regenerative current flows during the off period of the transistor 20.

  The switching element 2 generates a pulsed current by on / off control of the transistor 20. The LC resonance circuit including the capacitor 21 and the exciting coil 300 performs a resonance operation by receiving a pulsed current generated by the transistor 20. Thereby, in the exciting coil 300, the magnetic field which changes direction and magnitude | size efficiently arises.

  By the way, this kind of magnetic field generator has the following problems. Generally, when the ON duty width of the pulsed current supplied to the resonance circuit increases, the value of the current flowing through the current path 200 increases. In this case, the current value of the current passing through the connector 200 existing on the current path 200 may exceed the rated current value of the terminal of the connector 200. In that case, ignition or smoke may occur at the terminals of the connector 200.

JP 2005-190765 A

  FIG. 10 shows an example of a magnetic field generator that addresses such a problem. In the magnetic field generator 1000 shown in FIG. 10, a pair of branch current paths 201 are provided at each end of the current path 200. A connector 500 having a plurality of terminals corresponding to each branch current path 201 is provided. A pair of branch current paths 201 on the capacitor 21 side and a pair of branch current paths 201 on the excitation coil 300 side are connected by a connector 500.

  According to such a configuration, since the current flowing through the current path 200 is branched by the pair of branch current paths 201, the current value of the current passing through one terminal of the connector 500 is halved. This makes it difficult for a current having a current value exceeding the rated current of the terminal to flow through the terminal of the connector 500, so that it is possible to prevent the terminal of the connector 500 from generating fire or smoke.

  However, the magnetic field generator 1000 shown in FIG. 10 still has the following problems. For example, contact failure may occur between the terminal of the connector 500 and the branch current path 201 due to the branch current path 201 being inserted and removed from the connector 500 many times.

  In that case, since it is difficult for current to flow in the branch current path 201 in which contact failure occurs between the terminals of the connector 500 among the pair of branch current paths 201, the current flows to the other branch current path 201. Concentrate. In that case, if the current value of the concentrated current exceeds the rated current value of the terminal of the connector 500, it is conceivable that ignition or smoke generation occurs at that terminal.

  Such a problem cannot be solved only by a method of determining the ON duty width of the pulsed current supplied to the resonance circuit (see Patent Document 1). The reason is as follows.

  That is, since the method of Patent Document 1 does not determine a contact failure between the connector 500 and the branch current path 201, even if the ON duty width of the pulse current is not too large, Due to poor contact with the terminal of the connector 500, current may flow into the other terminal. In this case, the current value of the current flowing into the other terminal exceeds the rated current of the terminal. For this reason, this problem cannot be solved only by determining the ON duty width of the pulsed current supplied to the resonance circuit.

  The present invention was made to solve the above problems, and in a connection portion having a plurality of terminals for connecting current paths, when an abnormality such as a contact failure occurs in any of the terminals, An object of the present invention is to provide a magnetic field generator capable of preventing current flowing through a current path from being concentrated on other terminals, a heating device using the magnetic field generator, and an image forming apparatus including the heating device. To do.

The magnetic field generator according to the first aspect of the present invention is configured by winding a cable in which a plurality of electric wires covered with an insulating material are arranged in parallel, and each of the plurality of electric wires is connected to the cable. A first excitation coil that is wound in the same number of turns and winding direction as the number of turns and winding direction to form a second excitation coil, and each of the plurality of wires is provided corresponding to each of the plurality of wires. A plurality of switching elements for generating a current supplied to the plurality of switching elements, a plurality of first current paths provided corresponding to each of the plurality of switching elements, and through which the currents generated by the plurality of switching elements flow, A plurality of second current paths that are provided corresponding to each of the plurality of electric wires, and a plurality of second current paths through which current flows toward each of the plurality of electric wires, and a plurality of first terminals to which one ends of the plurality of first current paths are respectively connected. A plurality of second terminals to which one ends of the plurality of second current paths are respectively connected, and electrically connecting each of the plurality of first terminals and each of the plurality of second terminals, A first connecting portion that connects each of the plurality of first current paths and each of the plurality of second current paths, and each of the plurality of switching elements is connected to another switching element. Each of the plurality of first current paths is insulated from the other first current path, and each of the plurality of second current paths is separated from the other second current path. Each of the plurality of first terminals is insulated from the other first terminal, and each of the plurality of second terminals is between the other second terminal. in you, characterized in that it is insulated.

  According to this configuration, in the first excitation coil configured by winding the cable, each of the plurality of electric wires is wound in the same number of turns and winding direction as the number of turns and the winding direction of the cable. Thereby, each of a some electric wire comprises an exciting coil (2nd exciting coil) in the state wound, respectively. As a result, the first excitation coil includes a plurality of second excitation coils each composed of a plurality of electric wires.

  In addition, when the plurality of first terminals to which each of the plurality of first current paths is connected and the plurality of second terminals to which each of the plurality of second current paths are connected, the plurality of first current paths Each and each of the plurality of second current paths are electrically connected.

  Here, each of the plurality of first current paths is provided corresponding to each of the plurality of switching elements, and a current generated by the plurality of switching elements flows, while each of the plurality of second current paths is , Provided corresponding to each of the plurality of electric wires, and a current flows toward each of the plurality of electric wires.

  Therefore, when each of the plurality of first current paths and each of the plurality of second current paths are electrically connected, a plurality of elements from the switching element to the second excitation coil via the first terminal and the second terminal are provided. Current paths are formed.

  Furthermore, according to this configuration, each of the plurality of switching elements is insulated from the other switching elements, and each of the plurality of first current paths is insulated from the other first current path. Each of the plurality of second current paths is insulated from the other second current path, and each of the plurality of first terminals is insulated from the other first terminal. Each of the plurality of second terminals is insulated from the other second terminals.

  Accordingly, the plurality of current paths are insulated from other current paths. Thereby, when each of the plurality of first current paths and each of the plurality of second current paths are electrically connected, the switching element reaches the second excitation coil via the first terminal and the second terminal. A plurality of electrically independent current paths are formed.

  Further, according to this configuration, in one first exciting coil, the second exciting coil composed of each of the plurality of electric wires is provided, and the number of switching elements corresponding to the plurality of second exciting coils is provided. . From this, it can be seen that the number of switching elements is the same as the number of second exciting coils. In addition, since a plurality of first current paths through which currents generated by the plurality of switching elements flow are provided corresponding to the plurality of switching elements, the number of first current paths is also equal to the number of second exciting coils. It turns out that it is the same. Furthermore, since the plurality of second current paths are provided corresponding to each of the plurality of electric wires, and the current flows toward each of the plurality of electric wires, the number of the plurality of second current paths is also the second exciting coil. It turns out that it is the same as the number of.

  That is, it can be seen that the number of second exciting coils, switching elements, and first and second current paths are all the same as the number of second exciting coils.

  As described above, according to this configuration, a plurality of electrically independent current paths are formed from the switching element through the first terminal and the second terminal to the second exciting coil. Since the number of switching elements, the first and second terminals, and the second exciting coil that constitute each current path is one, a plurality of electrically independent current paths are used according to the number of second exciting coils. A number of current paths are formed.

  In other words, this configuration is a conventional configuration in which there is one current path from the switching element through the first terminal and the second terminal to the second excitation coil, and the current path is equal to the number of the second excitation coils. It is a branched configuration.

  Therefore, even if an abnormality such as a contact failure occurs in any one of the first terminal and the second terminal included in any of the current paths, and the current does not easily flow, the other first terminals and Since the other current path including the second terminal is electrically independent from the current supply path in which the current is difficult to flow, the current that should have flown in the current path where the abnormality has occurred is changed to the other current path. Does not flow into.

  Thereby, as long as the current value of the current flowing through each current path does not exceed the rated current value of the first terminal and the second terminal, any of the first terminal and the second terminal included in any of the current paths However, even if an abnormality occurs, the current value of the current flowing through the other current path does not change. Thereby, since the current of the current value exceeding the rated current value of the first and second terminals does not flow into the first and second terminals included in the other current paths, the first and second terminals included in the current paths. There is no ignition or smoke at the two terminals.

  Therefore, in the connection portion having a plurality of terminals for connecting the current paths, when an abnormality such as a contact failure occurs in any terminal, the current flowing in the current path is prevented from concentrating on the other terminals. be able to. For this reason, even if an abnormality such as a contact failure occurs in any of the terminals, ignition or smoke does not occur in the other terminals.

  In this way, each of the plurality of terminals is included, and an electrically independent current path is formed, so that the above effect can be achieved. Therefore, detection for detecting the current value of the current flowing into the terminal is detected. There is no need to provide a control unit for controlling the current value of the current flowing into the terminal and the terminal. As a result, the cost is suppressed.

A magnetic field generator according to a second aspect of the present invention is provided corresponding to each of a plurality of second excitation coils that receive a current and generate a magnetic field, and the second excitation coil, and the second excitation coil A plurality of switching elements for generating a current to be supplied to each of the coils, and a plurality of first current paths provided corresponding to each of the plurality of switching elements, through which the current generated by each of the switching elements flows. A plurality of second current paths that are provided corresponding to each of the plurality of second excitation coils, and a current flows toward each of the second excitation coils, and one end of the plurality of first current paths includes A plurality of first terminals connected to each other and a plurality of second terminals respectively connected to one ends of the plurality of second current paths are provided, and each of the plurality of first terminals and the plurality of second terminals are provided. Conduction with each of the terminals A plurality of first current paths and a first connection portion that connects the plurality of second current paths, and each of the plurality of second excitation coils includes another second current coil. Each of the plurality of switching elements is insulated from another switching element, and each of the plurality of first current paths is connected to another first current. Each of the plurality of second current paths is insulated from the other second current path, and each of the plurality of first terminals is connected to the other first current path. terminal are insulated between each of said plurality of second terminals, characterized in that it is insulated in between the other second terminal.

  According to this configuration, when the plurality of first terminals to which each of the plurality of first current paths is connected and the plurality of second terminals to which each of the plurality of second current paths are connected are electrically connected to each other, Each of the one current path and each of the plurality of second current paths are electrically connected.

  Here, each of the plurality of first current paths is provided corresponding to each of the plurality of switching elements, and a current generated by the plurality of switching elements flows, while each of the plurality of second current paths is , Provided corresponding to each of the plurality of second excitation coils, and a current flows toward each of the plurality of second excitation coils.

  Therefore, when each of the plurality of first current paths and each of the plurality of second current paths are electrically connected, a plurality of elements from the switching element to the second excitation coil via the first terminal and the second terminal are provided. Current paths are formed.

  Further, according to this configuration, each of the plurality of second excitation coils is insulated from the other second excitation coil, and each of the plurality of switching elements is between the other switching elements. Each of the plurality of first current paths is insulated from the other first current path, and each of the plurality of second current paths is between the other second current paths. Each of the plurality of first terminals is insulated from the other first terminal, and each of the plurality of second terminals is insulated from the other second terminal. Yes.

  Accordingly, the plurality of current paths are insulated from other current paths. Thereby, when each of the plurality of first current paths and each of the plurality of second current paths are electrically connected, the switching element reaches the second excitation coil via the first terminal and the second terminal. A plurality of electrically independent current paths are formed.

  Further, according to this configuration, in one first exciting coil, the second exciting coil composed of each of the plurality of electric wires is provided, and the number of switching elements corresponding to the plurality of second exciting coils is provided. . From this, it can be seen that the number of switching elements is the same as the number of second exciting coils. In addition, since a plurality of first current paths through which currents generated by the plurality of switching elements flow are provided corresponding to the plurality of switching elements, the number of first current paths is also equal to the number of second exciting coils. It turns out that it is the same. Furthermore, since the plurality of second current paths are provided corresponding to each of the plurality of electric wires, and the current flows toward each of the plurality of electric wires, the number of the plurality of second current paths is also the second exciting coil. It turns out that it is the same as the number of.

  That is, it can be seen that the number of second exciting coils, switching elements, and first and second current paths are all the same as the number of second exciting coils.

  As described above, according to this configuration, a plurality of electrically independent current paths are formed from the switching element through the first terminal and the second terminal to the second exciting coil. Since the number of switching elements, the first and second terminals, and the second exciting coil that constitute each current path is one, a plurality of electrically independent current paths are used according to the number of second exciting coils. A number of current paths are formed.

  In other words, this configuration is a conventional configuration in which there is one current path from the switching element through the first terminal and the second terminal to the second excitation coil, and the current path is equal to the number of the second excitation coils. It is a branched configuration.

  Therefore, even if an abnormality such as a contact failure occurs in one of the first terminal and the second terminal included in any one of the plurality of independent current paths, the current does not flow easily. Since the other current paths including the terminal and the second terminal are electrically independent from the current supply path where the current is difficult to flow, the current that should have flown in the current path where the abnormality has occurred is Does not flow into the current path.

  Thereby, as long as the current value of the current flowing through each current path does not exceed the rated current value of the first terminal and the second terminal, any of the first terminal and the second terminal included in any of the current paths However, even if an abnormality occurs, the current value of the current flowing through the other current path does not change. Thereby, since the current of the current value exceeding the rated current value of the first and second terminals does not flow into the first and second terminals included in the other current paths, the first and second terminals included in the current paths. There is no ignition or smoke at the two terminals.

  Therefore, in the connection portion having a plurality of terminals for connecting the current paths, when an abnormality such as a contact failure occurs in any terminal, the current flowing in the current path is prevented from concentrating on the other terminals. be able to. For this reason, even if an abnormality such as a contact failure occurs in any of the terminals, ignition or smoke does not occur in the other terminals.

  In this way, each of the plurality of terminals is included, and an electrically independent current path is formed, so that the above effect can be achieved. Therefore, detection for detecting the current value of the current flowing into the terminal is detected. There is no need to provide a control unit for controlling the current value of the current flowing into the terminal and the terminal. As a result, the cost is suppressed.

In the above-described configuration, the plurality of second exciting coils are wound in the same number of turns and winding as the number of turns and winding direction of the cable by winding a cable in which a plurality of wires covered with an insulating material are arranged in parallel. Each of the plurality of electric wires wound in a direction, and at one end of the cable, a terminal is provided for each of the plurality of electric wires, while at the other end of the cable, the terminal it is not preferable to a common terminal between a plurality of wires are provided.

  According to this configuration, a plurality of second exciting coils including a plurality of wires are formed by winding a cable in which a plurality of wires covered with an insulating material are arranged in parallel. Moreover, the terminal is provided for every some electric wire in the one end side of a cable.

  Thereby, the some electric current path | route derived | led-out from the connection part (connector) can be easily connected with respect to the end of a some 2nd excitation coil. Therefore, a plurality of electrically independent current paths from one end of the second exciting coil to the connecting portion (connector) can be easily formed.

In the above configuration, a third current path provided corresponding to each of the plurality of switching elements, provided with a plurality of first branch current paths, and connected to the common terminal, the plurality of first branch currents A fourth current path provided with a plurality of second branch current paths corresponding to the path, a plurality of third terminals respectively connected to one ends of the plurality of first branch current paths, and the plurality of second A plurality of fourth terminals each having one end of each of the branch current paths connected thereto, and by connecting each of the plurality of third terminals and each of the plurality of fourth terminals, Any one of a second connection portion that connects each of the first branch current paths and each of the plurality of second branch current paths, the plurality of first branch current paths, and the plurality of second branch current paths A detection unit for detecting a current value of a current flowing through one side; At least one of the issued the current value, but when more than a predetermined set current value, and a control unit for stopping the supply of current to the plurality of switching elements, not preferable further comprise a.

  According to this configuration, when an overcurrent occurs in any one of the plurality of first branch current paths or any of the plurality of second branch current paths, the switching element is controlled by the control unit. Stop supplying current. As a result, the current does not flow into the current path in which the overcurrent has occurred, so that the third terminal and the fourth terminal of the second connection portion connecting the first branch current path and the second branch current path can be protected. .

In the above-described configuration, the plurality of second exciting coils are wound in the same number of turns and winding as the number of turns and winding direction of the cable by winding a cable in which a plurality of wires covered with an insulating material are arranged in parallel. is composed of each of the plurality of electric wires wound in the direction at both ends of the cable, it is not preferable that the terminal is provided for each of the plurality of electric wires.

  According to this configuration, a plurality of wires wound in the same number of turns and winding direction as the number of turns and winding direction of the cable are wound by winding a cable in which a plurality of wires covered with an insulating material are arranged in parallel. A plurality of second exciting coils made of each of the above are configured. Moreover, the terminal is provided for every some electric wire in the both ends part side of a cable.

  Thereby, it is possible to easily connect a plurality of current paths derived from a certain connecting portion (connector) to one end of the plurality of second exciting coils. Furthermore, it is possible to easily connect a plurality of current paths derived from other connection portions (connectors) to the other ends of the plurality of second excitation coils.

  Accordingly, it is possible to easily form a plurality of electrically independent current paths from a certain connection portion (connector) to the other connection portion (connector) through the second exciting coil.

In the above configuration, each of the plurality of second current paths is connected to one end of each of the plurality of second excitation coils, and a third current path provided with a plurality of first branch current paths; A plurality of fifth current paths connected to the other end of each of the plurality of second exciting coils; a plurality of third terminals each connected to one end of each of the first branch current paths; A plurality of fifth terminals to which one end of each of the fifth current paths is respectively connected, and by conducting each of the plurality of third terminals and each of the plurality of fifth terminals, a third connecting portion for connecting the each of the plurality of first branch current paths each and the plurality of fifth current path, have preferably further comprise a.

  According to this configuration, each of the plurality of third terminals and each of the plurality of fifth terminals are brought into conduction by the third connection portion, thereby each of the plurality of first branch current paths and the plurality of fifth current paths. Conducts between the two. On the other hand, as described above, each of the plurality of first terminals and each of the plurality of second terminals are brought into conduction by the first connection portion, whereby each of the plurality of first current paths and each of the plurality of first terminals are connected. Conduction is established between each of the two current paths.

  As a result, a plurality of electrically independent current paths from the first current path through the first terminal and the second terminal to one end of the second excitation coil are formed on one end side of the plurality of second excitation coils. Is done. On the other hand, a plurality of electrically independent current paths from the first branch current path to the other end of the second exciting coil through the third terminal, the fifth terminal, and the fifth current path are a plurality of first current paths. 2 is formed at the other end of the exciting coil.

  This makes it difficult for a current to flow through the terminal due to an abnormality of the terminal in any of the first connection portion including the first and second terminals and the third connection portion including the third and fifth terminals. Even if it does, current does not flow into terminals other than the terminal in the connection portion.

  As a result, even if it becomes difficult for a current to flow to the terminal of the connection portion on either the one end side or the other end side of the plurality of second excitation coils, heat generation of terminals other than the terminal at the connection portion is prevented. be able to.

The above configuration further includes two power lines for transmitting power, and a plurality of capacitors. The two power lines include a plurality of switching elements and a plurality of capacitors. The plurality of series circuits are connected in parallel, and the one end side of each of the plurality of capacitors is connected to the common terminal of the plurality of second excitation coils, while the plurality of capacitors of the each other end of it is not preferable that each of terminals of the plurality of second excitation coil is connected.

  According to this configuration, a plurality of series circuits composed of switching elements and capacitors are connected in parallel to the two power lines, and a plurality of second exciting coils are provided at one end of each capacitor. Are connected to the other terminals of the respective capacitors, and the respective terminals of the plurality of second exciting coils are connected to the other terminals of the respective capacitors.

  Thereby, a plurality of resonance circuits each including a plurality of capacitors and the second excitation coil corresponding to the capacitors are obtained.

  Here, the inductance of the second excitation coil is such that the cross-sectional area, the number of turns, and the length (the length of the magnetic path) of each of the second excitation coils are one excitation coil. Is the same as the cross-sectional area, the number of turns, and the length (the length of the magnetic path) of the exciting coil. Therefore, the inductance of each of the second exciting coils is the same as the inductance of the exciting coils when the plurality of second exciting coils are assumed to be one exciting coil.

  Therefore, in order to obtain the same power as that of a conventional LC resonance circuit configured with one capacitor and one excitation coil, the capacitance in the conventional LC resonance circuit is obtained by dividing by the number of capacitors. It can be seen that the electrostatic capacity is sufficient.

  Thus, if the capacitance in the conventional LC resonance circuit is obtained by dividing the capacitance by the number of capacitors, the electric power generated by each of the LC resonance circuits is converted into the capacitance of the conventional LC resonance circuit. The power obtained by dividing by the number of. As a result, the power generated by the entire plurality of LC resonance circuits is the same as the power generated by the conventional LC resonance circuit. As a result, the same power as in the conventional configuration can be obtained.

The above configuration further includes two power lines for transmitting power, and a plurality of capacitors. The two power lines include a plurality of switching elements and a plurality of capacitors. A plurality of series circuits are connected in parallel, and one end side of each of the plurality of capacitors has each of the third current path, each of the first branch current paths, and each of the plurality of fifth current paths. A terminal on one end side of each of the plurality of second excitation coils is connected to each other, and the other end side of each of the plurality of capacitors is connected to each of the plurality of second excitation coils. it is not preferable that the other end of the terminal of is connected.

  According to this configuration, a plurality of series circuits including a switching element and a capacitor are connected in parallel to the two power lines, and the third current path, the plurality of the plurality of series circuits are connected to one end of each capacitor. The terminals on one end side of each of the plurality of second exciting coils are connected to the other ends of the respective capacitors through the first branch current paths and the plurality of fifth current paths, respectively. A terminal on the other end side of each of the plurality of second exciting coils is connected to the side.

  Thereby, a plurality of resonance circuits each including a plurality of capacitors and the second excitation coil corresponding to the capacitors are obtained.

  Here, the inductance of the second excitation coil is such that the cross-sectional area, the number of turns, and the length (the length of the magnetic path) of each of the second excitation coils are one excitation coil. Is the same as the cross-sectional area, the number of turns, and the length (the length of the magnetic path) of the exciting coil. Therefore, the inductance of each of the second exciting coils is the same as the inductance of the exciting coils when the plurality of second exciting coils are assumed to be one exciting coil.

  Therefore, in order to obtain the same power as that of a conventional LC resonance circuit configured with one capacitor and one excitation coil, the capacitance in the conventional LC resonance circuit is obtained by dividing by the number of capacitors. It can be seen that the electrostatic capacity is sufficient.

  Thus, if the capacitance in the conventional LC resonance circuit is obtained by dividing the capacitance by the number of capacitors, the electric power generated by each of the LC resonance circuits is converted into the capacitance of the conventional LC resonance circuit. The power obtained by dividing by the number of. As a result, the power generated by the entire plurality of LC resonance circuits is the same as the power generated by the conventional LC resonance circuit. As a result, the same power as in the conventional configuration can be obtained.

In the above structure, the first connecting portion, with each of the plurality of first terminals, it is not preferable and each of the plurality of second terminals are drawer connector in contact.

  According to this structure, since the 1st connection part is a drawer connector, each of a some 1st terminal and each of a some 2nd terminal can be made to contact easily. Further, the contact between each of the plurality of first terminals and each of the plurality of second terminals can be easily released.

In the above configuration, one of the plurality of first terminals and the plurality of second terminals is configured with a plurality of screw terminals, and the plurality of first terminals and the plurality of first terminals the other of the two terminals, it is not preferable that consists of a screw terminal block is a terminal to be attached to each of the plurality of screw terminals.

  According to this structure, since the 1st connection part can be comprised with an inexpensive screw terminal block, cost is suppressed.

A heating device according to a third aspect of the present invention includes the above-described magnetic field generator, and is configured to induction-heat an object to be heated by the magnetic field generated in the magnetic field generator. It shall be the.

  According to this configuration, since the magnetic field generator having the above-described configuration is provided, a heating device that exhibits the above-described effects can be provided.

An image forming apparatus according to a fourth aspect of the present invention includes an image forming unit that forms a toner image representing an image on a sheet and the heating device described above, and the toner formed on the sheet. it characterized in that it comprises a fixing device for thermally fixing an image.

According to this configuration, since the fixing device having the above-described configuration is provided, an image forming apparatus that exhibits the above-described effects can be provided.
A magnetic field generation apparatus according to a fifth aspect of the present invention is provided corresponding to each of a plurality of excitation coils that receive a current and generate a magnetic field, and each of the plurality of excitation coils, and is supplied to each of the plurality of excitation coils A plurality of switching elements for generating a current to be generated, a plurality of first current paths provided corresponding to each of the plurality of switching elements, through which the current generated by each of the plurality of switching elements flows, and the plurality of the plurality of switching elements A plurality of second current paths, each of which is provided corresponding to each of the plurality of excitation coils, and a plurality of second current paths through which current flows toward each of the plurality of excitation coils, and one end of each of the plurality of first current paths is connected. One terminal and a plurality of second terminals to which one ends of the plurality of second current paths are respectively connected are provided, and each of the plurality of first terminals is electrically connected to each of the plurality of second terminals. This And a first connection part that connects the plurality of first current paths and the plurality of second current paths, wherein each of the plurality of excitation coils is insulated from other excitation coils. Each of the plurality of switching elements is insulated from the other switching elements, and each of the plurality of first current paths is insulated from the other first current path. Each of the plurality of second current paths is insulated from the other second current path, and each of the plurality of first terminals is insulated from the other first terminal. Each of the plurality of second terminals is insulated from the other second terminal, and the plurality of exciting coils are cables in which a plurality of electric wires covered with an insulating material are arranged in parallel. By being wound, it is wound with the same number of turns and winding direction as the number of turns and winding direction of the cable. Each of the plurality of turned electric wires is configured, and on one end portion side of the cable, a terminal connected to each of the plurality of second current paths is provided for each of the plurality of electric wires. In the other end portion of the cable, a common terminal is provided between the plurality of electric wires, and further includes two power lines for transmitting power and a plurality of capacitors. In the power line, a plurality of series circuits each including the plurality of switching elements and the plurality of capacitors are connected in parallel, and one end side of each of the plurality of capacitors has the plurality of the plurality of series circuits. While the common terminal in the exciting coil is connected, each of the plurality of first current paths is connected to the other end of each of the plurality of capacitors.
A magnetic field generation device according to a sixth aspect of the present invention is provided corresponding to each of a plurality of excitation coils that receive a current and generate a magnetic field, and the plurality of excitation coils, and supplies the excitation coils to each of the plurality of excitation coils. A plurality of switching elements for generating a current to be generated, a plurality of first current paths provided corresponding to each of the plurality of switching elements, through which the current generated by each of the plurality of switching elements flows, and the plurality of the plurality of switching elements A plurality of second current paths, each of which is provided corresponding to each of the plurality of excitation coils, and a plurality of second current paths through which current flows toward each of the plurality of excitation coils, and one end of each of the plurality of first current paths is connected. One terminal and a plurality of second terminals to which one ends of the plurality of second current paths are respectively connected are provided, and each of the plurality of first terminals is electrically connected to each of the plurality of second terminals. This And a first connection part that connects the plurality of first current paths and the plurality of second current paths, wherein each of the plurality of excitation coils is insulated from other excitation coils. Each of the plurality of switching elements is insulated from the other switching elements, and each of the plurality of first current paths is insulated from the other first current path. Each of the plurality of second current paths is insulated from the other second current path, and each of the plurality of first terminals is insulated from the other first terminal. Each of the plurality of second terminals is insulated from the other second terminal, and the plurality of exciting coils are cables in which a plurality of electric wires covered with an insulating material are arranged in parallel. By being wound, it is wound with the same number of turns and winding direction as the number of turns and winding direction of the cable. Each of the plurality of turned electric wires is configured, and at both ends of the cable, a terminal is provided for each of the plurality of electric wires, and each of the plurality of second current paths is formed of the plurality of electric wires. A third current path connected to one end of each of the exciting coils, provided corresponding to each of the plurality of switching elements, and provided with a plurality of first branch current paths; and each of the plurality of exciting coils. a plurality of fifth current path connected to the other end of said first branch current paths each third multiple of which one end is connected to the terminals of, one end of each of the plurality of fifth current path A plurality of fifth terminals connected to each other are provided, and each of the plurality of third terminals and each of the plurality of fifth terminals are electrically connected to each of the plurality of first branch current paths. A third connecting portion connecting each of the plurality of fifth current paths; , And further comprising two power lines for transmitting power, and a plurality of capacitors, wherein the two power lines include each of the plurality of switching elements and each of the plurality of capacitors. A plurality of series circuits are connected in parallel, and one end of each of the plurality of capacitors is connected to each of the third current path, each of the first branch current paths, and each of the plurality of fifth current paths. A terminal on the other end side of each of the plurality of exciting coils is connected to each other through each of the plurality of first current paths and the other end side of each of the plurality of capacitors. A terminal on one end side of each of the plurality of exciting coils is connected through each of the plurality of second current paths .

  According to the present invention, in a connection portion having a plurality of terminals for connecting current paths, when an abnormality such as a contact failure occurs in any terminal, the current flowing in the current path is concentrated on other terminals. Can be prevented. For this reason, even if an abnormality such as a contact failure occurs in any of the terminals, ignition or smoke does not occur in the other terminals.

  In this way, each of the plurality of terminals is included, and an electrically independent current path is formed, so that the above effect can be achieved. Therefore, detection for detecting the current value of the current flowing into the terminal is detected. There is no need to provide a control unit for controlling the current value of the current flowing into the terminal and the terminal. As a result, the cost is suppressed.

It is the circuit diagram which showed an example of the magnetic field generator which concerns on one Embodiment of this invention. It is the figure which showed an example of the structure of the connector used with the magnetic field generator which concerns on one Embodiment of this invention. It is the figure which showed an example of the structure of the screw terminal block used with the magnetic field generator which concerns on one Embodiment of this invention. It is the circuit diagram which showed the other example of the structure of the magnetic field generator which concerns on one Embodiment of this invention. It is the circuit diagram which showed the further another example of the structure of the magnetic field generator which concerns on one Embodiment of this invention. It is the external view which showed an example of the structure of the exciting coil. It is the external view which showed the other example of the structure of the exciting coil. 1 is a longitudinal sectional view showing a mechanical configuration of an image forming apparatus according to an embodiment of the present invention. It is the figure which showed the conventional magnetic field generator. It is the figure which showed the conventional magnetic field generator.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 8 is a longitudinal sectional view showing the mechanical configuration of the image forming apparatus according to the embodiment of the present invention. The image forming apparatus A generally includes a main body portion 32, a scanner portion 33 disposed above the main body portion 32, and an ADF 34 disposed above the scanner portion 33. Is done.

  In the main body 32, one of the recording sheets 41a, 42a, 43a, 44a loaded in one or a plurality of trays 41, 42, 43 and the manual feed tray 44 is taken out one by one by the take-in rollers 41b, 42b, 43b, 44b. Then, the timing is adjusted by the registration rollers 45 and 46, and then conveyed to the image forming unit 47. The image forming unit 47 includes a charger (not shown), a laser writing unit, a developing unit, a transfer unit 47b, a cleaning unit (not shown), and the like around the photosensitive drum 47a, and forms an image on a recording sheet by electrophotography. . The toner image thus formed on the recording paper is fixed by a heating device 48 including the magnetic field generator 1 described later, and is discharged onto the paper discharge tray 51 from the discharge rollers 49 and 50.

  Image data given to the laser writing unit is read by the scanner unit 33. The scanner unit 33 includes a scanning unit 53 that irradiates the original with illumination light through the document table 52 and receives reflected light under the document table 52 made of a plate-shaped transparent plate such as a glass plate, and a scanning unit. A mirror unit 54 for further reflecting the reflected light obtained at 53, an imaging lens 55 for collecting the reflected light from the mirror unit 54, and a CCD 14 for photoelectrically converting the reflected light imaged by the imaging lens 55; It is configured with.

  The scanning unit 53 is driven in the sub-scanning direction by a stepping motor (not shown), for example. The scanning unit 53 is displaced at a speed V and the mirror unit 54 is displaced at a speed V / 2 in the left-right direction of FIG. 8, that is, in the sub-scanning direction. The original image is always formed on the CCD 14 with the same optical path length.

  On the other hand, in the ADF 34 that sequentially takes in sheet originals, the originals 62 stacked on the original tray 61 are taken out one by one by the take-in rollers 63 and supplied to the curved conveyance path 64. And it is conveyed by the conveyance roller 65,66,67,68 provided in the curved conveyance path 64 to the reading window 82 which consists of plate-shaped transparent plates, such as a glass plate extended in a main scanning direction, and a scanning part is carried out to the reading window 82. The original images are sequentially read in a state where 53 faces, and are then discharged onto the discharge tray 81 by the discharge rollers 69 and 80.

  The scanning unit 53 includes a cold-cathode tube 531 (light source), a reflector 532 that irradiates light emitted from the cold-cathode tube 531 toward the document table 52 and the reading window 82, and the document table 52 and the reading window 82 from the document. And a mirror 533 for reflecting the reflected light obtained by passing through the mirror unit 54 to the mirror unit 54.

  FIG. 1 is a circuit diagram showing an example of a magnetic field generator according to an embodiment of the present invention. FIG. 2 is a diagram showing an example of the configuration of a connector used in the magnetic field generator according to one embodiment of the present invention. FIG. 3 is a diagram showing an example of the configuration of a screw terminal block used in the magnetic field generator according to one embodiment of the present invention.

  Here, in the magnetic field generator 1 shown in FIG. 1, the DC power supplied to the power line L is power generated by rectifying and smoothing commercial power by a diode bridge and a smoothing capacitor (not shown). The same applies to the magnetic field generator 1 shown in FIGS. 4 and 5.

  The magnetic field generator 1 shown in FIG. 1 functions as a heating device 48 that heats the object to be heated 13. A magnetic field generator 1 shown in FIG. 1 includes a plurality of switching elements 2 that generate a pulsed current from DC power supplied to a power line L, and an exciting coil 3 that receives a current and generates a magnetic field. Here, as will be described later, the excitation coil 3 is a single excitation coil (first excitation coil) formed by winding a cable in which a plurality of wires covered with an insulator are arranged in parallel. ). The exciting coil 3 includes a plurality of exciting coils (second exciting coils) 30 made of electric wires. Each of the plurality of second exciting coils 30 is configured by winding each of a plurality of electric wires arranged on the cable.

  Each of the plurality of switching elements 2 is provided corresponding to each of the plurality of second exciting coils 30. That is, the number of switching elements 2 is the same as the number of second exciting coils 30. For example, in this embodiment, since the excitation coil 3 is provided with the two second excitation coils 30, the two switching elements 2 are provided. This switching element 2 is insulated from other switching elements 2.

  In addition, the magnetic field generator 1 includes a plurality of first current paths 4 corresponding to the plurality of switching elements 2. The first current path 4 is insulated from the other first current paths 4. The magnetic field generator 1 also includes a plurality of second current paths 5 corresponding to the plurality of second excitation coils 30. The second current path 5 is insulated from the other second current paths 5.

  Furthermore, the magnetic field generator 1 includes a first connection unit 7. The first connection unit 7 includes a plurality of first current path side terminals (first terminals) 700 to which each of the plurality of first current paths 4 is attached, and a plurality of to which each of the plurality of second current paths 5 is attached. The second current path side terminal (second terminal) 710 is provided. The first connection unit 7 electrically connects each of the plurality of first current path side terminals 700 and the plurality of second current path side terminals 710 to thereby establish a plurality of first current paths 4 and a plurality of second current paths 5. Connect.

  Here, the first current path side terminal 700 is insulated from the other first current path side terminals 700. Further, the second current path side terminal 710 is insulated from the other second current path side terminal 710. As a result, when the plurality of first current paths 4 and the plurality of second current paths 5 are connected by the first connection portion 7, the second current passes from the switching element 2 through the first terminal 700 and the second terminal 710. A plurality of electrically independent current paths to the exciting coil 30 are formed. In the present embodiment, as described above, since the two switching elements 2 and the two second exciting coils 30 are provided, two electrically independent current paths are formed.

  Such a 1st connection part 7 can be comprised by the drawer connector shown by FIG. 2, for example. By configuring the first connection portion 7 with a drawer connector, each of the plurality of first current path side terminals 700 and each of the plurality of second current path side terminals 710 can be easily connected. Furthermore, the connection between each of the plurality of first current path side terminals 700 and each of the plurality of second current path side terminals 710 can be easily disconnected.

  When the 1st connection part 7 is comprised by the drawer connector shown by FIG. 2, it becomes the structure shown below. For example, each of the plurality of first current path side terminals 700 and each of the plurality of first current paths 4 are connected inside the receiving member 70. On the other hand, each of the plurality of second current path side terminals 710 and each of the plurality of second current paths 5 are connected inside the insertion member 71.

  Since the 1st connection part 7 is set as such a structure, only by inserting the insertion member 71 in the receiving member 70, each of the some 1st current path side terminal 700 and the some 2nd current path side terminal 710 are included. Can be conducted to each other. On the other hand, the electrical connection between each of the plurality of first current path side terminals 700 and each of the plurality of second current path side terminals 710 can be interrupted only by pulling out the insertion member from the receiving member 70.

  As a result, a device such as a lid, a door, a paper cassette, etc. on the main body side is interlocked with the operation of a member that performs opening / closing operations, insertion / extraction operations, etc. By inserting the insertion member 71 into the receiving member 70, the plurality of first current path side terminals 700 and the plurality of second current path side terminals 710 can be electrically connected. In addition, by inserting the insertion member 71 from the receiving member 70 in conjunction with a human operation, electrical connection between each of the plurality of first current path side terminals 700 and each of the plurality of second current path side terminals 710 is performed. Can be blocked.

  Moreover, as the 1st connection part 7 which connects the some 1st current path 4 and the some 2nd current path 5, a screw terminal block as shown in FIG. 3 may be used. When the 1st connection part 7 is comprised with the screw terminal block shown by FIG. 3, it becomes the structure shown below. For example, in the first connection portion 7, each of the plurality of first current path side terminals 700 is a screw terminal, and each of the plurality of second current path side terminals 710 is connected to each screw terminal by screwing. To do.

  Returning to FIG. 1, the configuration of the magnetic field generator 1 will be further described. As shown in FIG. 1, in the magnetic field generator 1, one third current path 6 is connected to each switching element 2. A plurality of first branch current paths 12 are provided at one end of the third current path 6. Here, in the present embodiment, two first branch current paths 12 are provided in accordance with the number of second exciting coils 30.

  Further, a fourth current path 16 provided with a plurality of second branch current paths 11 corresponding to the plurality of first branch current paths 12 is provided. Here, the number of the plurality of second branch current paths 11 is the same as the number of the plurality of first branch current paths 12. For example, in the present embodiment, two second branch current paths 11 are provided in accordance with the number of first branch current paths 12.

  The plurality of second exciting coils 30 include a common terminal P. That is, in the present embodiment, the plurality of second excitation coils 30 are provided in the excitation coil 3 in a form separated from the terminal P. The fourth current path 16 is connected to the terminal P.

  In the magnetic field generator 1, each of the plurality of first branch current paths 12 and each of the plurality of second branch current paths 11 are connected by the second connection portion 8. The second connection portion 8 includes a plurality of first branch current path side terminals (third terminals) 701 to which each of the plurality of first branch current paths 12 is attached, and each of the plurality of second branch current paths 11. A plurality of attached second branch current path side terminals (fourth terminals) 711 are provided. The second connection portion 8 is electrically connected to each of the plurality of first branch current path side terminals 701 and each of the plurality of second branch current path side terminals 711 to thereby connect each of the plurality of first branch current path side terminals 711 to each other. Each of the plurality of second branch current paths 11 is connected. Such a 2nd connection part 8 can be comprised by the drawer connector shown by FIG. 2, for example. Moreover, it can also be comprised with the screw terminal block shown by FIG.

  When the second connecting portion 8 is configured by a drawer connector, for example, as shown in FIG. 2, each of the plurality of first branch current path side terminals 701 and each of the plurality of first branch current paths 12 are The connection is made inside the receiving member 70. On the other hand, each of the plurality of second branch current path side terminals 711 and each of the plurality of second branch current path 11 are connected inside the insertion member 71.

  When the second connection portion 8 is configured using a screw terminal block, for example, as shown in FIG. 3, each of the plurality of first branch current path side terminals 701 is a screw terminal, and each screw Each of the plurality of second branch current path side terminals 711 is connected to the terminal by screwing.

  In the magnetic field generator 1, each switching element 2 includes a transistor 20 that generates a pulsed current by switching DC power supplied through the power line L. Here, the transistor 20 is formed of an insulated gate bipolar transistor in the present embodiment.

  A capacitor 21 is connected to each transistor 20 in series. Then, one end of the first current path 4 and one end of the third current path 6 are connected to each of both terminals of the capacitor 21. Each capacitor 21 constitutes an LC resonance circuit with any second excitation coil 30 existing on the other end side of the first current path 4 and the third current path 6.

  Hereinafter, the basic operation of the magnetic field generator 1 will be described. DC power is supplied to the power line L. Each transistor 20 is turned on and off by a pulse signal input to the gate terminal. When the transistor 20 is in the on state, the collector current flows, so that the current path formed by the first to fourth current paths 4 to 6 and 16 is in the conductive state, while when the transistor 20 is in the off state, Since the collector current does not flow, the current path becomes non-conductive. As a result, each transistor 20 generates a pulsed current from the DC power supplied to the power line L. A diode 22 through which a regenerative current flows is provided between the emitter terminal and the collector terminal of the transistor 20. When the transistor 20 is off, a regenerative current flows through the diode 22. This regenerative current is supplied to the current path. As a result, a current flows through the current path even when the transistor 20 is in the OFF state. For this reason, a pulsed current having a constant current value or higher is always supplied to the current path.

  The controller 10 outputs pulses having the same phase to each transistor 20, thereby turning on / off each transistor 20 at the same timing. Thus, each transistor 20 supplies pulsed currents having the same phase to each current path.

  The pulsed current generated by each transistor 20 is supplied to each LC resonance circuit composed of the capacitor 21 and the second exciting coil 30. Thereby, a resonance operation is performed between the capacitor 21 and the second exciting coil 30, and a high-frequency current flows in each current path. At that time, in the second exciting coil 30, a magnetic field whose direction and size change at a constant frequency is generated as time passes. Thereby, an eddy current is efficiently generated in the heated body 13 made of a magnetic body, and the heated body is heated.

  According to this configuration, as described above, the plurality of first current path side terminals 700 to which each of the plurality of first current paths 4 is connected and the plurality of second current paths 5 to which each of the plurality of second current paths 5 is connected. When the second current path side terminal 710 is conducted, each of the plurality of first current paths 4 and each of the plurality of second current paths 5 are electrically connected.

  Therefore, when each of the plurality of first current paths 4 and each of the plurality of second current paths 5 are electrically connected, the switching element 2 passes through the first current path side terminal 700 and the second current path side terminal 710. A plurality of electrically independent current paths to the second exciting coil 30 are formed.

  Furthermore, according to this configuration, each of the plurality of switching elements 2 is insulated from the other switching element 2, and each of the plurality of first current paths 4 is separated from the other first current paths 4. And each of the plurality of second current paths 5 is insulated from the other second current path 5, and each of the plurality of first current path side terminals 700 is connected to the other second current path 5. The first current path side terminal 700 is insulated from each other, and each of the plurality of second current path side terminals 710 is insulated from the other second current path side terminal 710.

  Accordingly, the plurality of current paths are insulated from other current paths. Thus, when each of the plurality of first current paths 4 and each of the plurality of second current paths 5 are electrically connected, the first current path side terminal 700 and the second current path side terminal 710 are connected from the switching element 2. A plurality of electrically independent current paths extending to the second exciting coil 30 are formed.

  As a result, even if an abnormality such as a contact failure occurs in any of the first current path side terminal 700 and the second current path side terminal 710 included in any one of the plurality of current paths, the current does not flow easily. Since the other current paths including the other first current path side terminal 700 and the second current path side terminal 710 are electrically independent from the current path in which the current is less likely to flow, The current that should have flown does not flow into other current paths.

  Therefore, even if an abnormality occurs in any one of the first current path side terminal 700 and the second current path side terminal 710 included in any current path, the current value of the current flowing through the other current path does not change. Thereby, since the current of the current value exceeding the rated current value does not flow into each of the first current path side terminal 700 and the second current path side terminal 710 included in the other current paths, ignition and smoke are not generated at the terminals. Does not occur.

  FIG. 4 is a circuit diagram showing another example of the configuration of the magnetic field generator 1 according to one embodiment of the present invention. In the magnetic field generator 1 shown in FIG. 4, the detection unit 9 that detects the current value of the current flowing through the first branch current path 12 is provided in the pair of first branch current paths 12. Here, as an example of the detection unit 9, a CT converter (Current Transformer) that detects the current value of the high-frequency current flowing through the first branch current path 12 can be cited.

  In the magnetic field generator 1 shown in FIG. 4, when the current value (for example, effective value) detected by the detection unit 9 exceeds the preset current value, the control unit 10 controls the gate terminal of each transistor 20. Stop pulse output. As a result, no pulsed current is supplied to the LC resonance circuit composed of the capacitor 21 and the second exciting coil 30, and the current flowing in the resonance circuit is attenuated. Therefore, since the current flowing through the first branch current path side terminal 701 and the second branch current path side terminal 711 of the second connection portion 8 is attenuated, the first branch current path side terminal 701 and the second branch current path side terminal 711 are appropriately set. Can be protected.

  Furthermore, in the magnetic field generator 1 described above, a plurality of series circuits each including a plurality of switching elements 2 and a plurality of capacitors 21 are connected in parallel to the two power lines L. . Further, a common terminal P is connected to one end side of each of the plurality of capacitors 21 via the third current path 6 and the fourth current path 16. On the other hand, one end (terminal) of each of the plurality of second exciting coils 30 is connected to the other end side of each of the plurality of capacitors 21 via each of the first current paths 4 and each of the second current paths 5. 300; see FIG. 6).

  According to this configuration, a plurality of resonance circuits each including the plurality of capacitors 21 and the second exciting coil 30 corresponding to the capacitors 21 are obtained.

  Here, the inductance of the second excitation coil 30 is such that the cross-sectional area, the number of turns, and the length (the length of the magnetic path) of each of the second excitation coils 30 are equal to those of the plurality of second excitation coils 30. It is the same as the cross-sectional area, the number of turns, and the length (the length of the magnetic path) of the exciting coil (exciting coil 3) when it is assumed that there are two exciting coils. Therefore, the inductance of each of the second exciting coils 30 is the same as the inductance of the first exciting coil 3.

  Therefore, in order to obtain the same power as that of the conventional LC resonance circuit configured by providing one capacitor and one excitation coil, the capacitance in the conventional LC resonance circuit is obtained by dividing by the number of capacitors 21. It can be seen that the obtained capacitance is sufficient.

  In this way, if the capacitance in the conventional LC resonance circuit is divided by the number of capacitors 21, the power generated by each LC resonance circuit is The electric power obtained by dividing by the number of capacitors 21. As a result, the power generated by the entire plurality of LC resonance circuits is the same as the power generated by the conventional LC resonance circuit. As a result, the same power as in the conventional configuration can be obtained.

  FIG. 5 is a circuit diagram showing still another example of the configuration of the magnetic field generator 1 according to one embodiment of the present invention.

  In the magnetic field generator 1 shown in FIG. 5, the second current path 5 is connected to one end side of each of the plurality of second exciting coils 30. The fifth current path 17 is connected to the other end of each of the plurality of second exciting coils 30.

  The magnetic field generator 1 further includes a third connection portion 15 that connects each of the plurality of fifth current paths 5 and each of the first branch current paths 12 described above. The third connection portion 15 includes a plurality of first branch current path side terminals (third terminals) 701 to which each of the plurality of first branch current paths 12 is attached, and a plurality of to which each of the plurality of fifth current paths 17 is attached. The fifth current path side terminal (fifth terminal) 712 is provided. The third connection portion 15 electrically connects each of the plurality of first branch current path side terminals 701 and the plurality of fifth current path side terminals 712, thereby allowing each of the plurality of first branch current path 12 and each of the plurality of first branch current path side terminals 701 to conduct. Each of the five current paths 17 is connected. Such a 3rd connection part 15 can be comprised by the drawer connector shown by FIG. 2, for example. Moreover, it can also be comprised with the screw terminal block shown by FIG.

  When the third connecting portion 15 is configured by a drawer connector, for example, as shown in FIG. 2, each of the plurality of first branch current path side terminals 701 and each of the plurality of first branch current paths 12 are The connection is made inside the receiving member 70. On the other hand, each of the plurality of fifth current path side terminals 712 and each of the plurality of fifth current paths 17 are connected inside the insertion member 71.

  Further, when the third connection portion 15 is configured using a screw terminal block, for example, as shown in FIG. 3, each of the plurality of first branch current path side terminals 701 is a screw terminal. Each of the plurality of fifth current path side terminals 712 is connected to the screw terminal by screwing.

  Since the magnetic field generator 1 shown in FIG. 5 is configured as described above, the second exciting coil 30 of the second exciting coil 30 passes through the first current path side terminal 700 and the second current path side terminal 710 from the first current path 4. A plurality of electrically independent current paths to one end (terminal 300; see FIG. 7) are formed on one end side of the plurality of second exciting coils 30. On the other hand, the other end of the second exciting coil 30 from the first branch current path 12 through the first branch current path side terminal 701, the fifth current path side terminal 712, and the fifth current path (terminal 300; see FIG. 7). A plurality of electrically independent current paths to the other end side of the plurality of second exciting coils 30 are formed.

  Thereby, even if it becomes difficult for the current to flow to the terminal 700 or 710 due to the abnormality of the terminal 700 or 710 or the like occurring in the first connection portion 7 including the first current path side terminal 700 and the second current path side terminal 710, In the 1st connection part 7, an electric current does not flow into terminals other than the terminal.

  In addition, even if the abnormality of the terminal 701 or 712 or the like occurs in the third connection portion 15 including the first branch current path side terminal 701 and the fifth current path side terminal 712, the current does not easily flow to the terminal 701 or 712. In the third connection portion 15, no current flows into terminals other than the terminal.

  As a result, heat generation of the terminals 700, 710, 701, and 712 can be prevented on either the one end side or the other end side of the plurality of second excitation coils 30.

  Further, in the magnetic field generator 1 described above, a plurality of series circuits including each of the plurality of switching elements 2 and each of the plurality of capacitors 21 are connected in parallel to the two power lines L. . In addition, a plurality of second excitation coils are provided on one end side of each of the plurality of capacitors 21 via the third current path 6, the first branch current path 12, and the plurality of fifth current paths 17. One end of each of the terminals 30 (terminal 300; see FIG. 7) is connected. Further, the other end of each of the plurality of second exciting coils 30 is connected to the other end side of each of the plurality of capacitors 21 via each of the first current paths 4 and each of the second current paths 5 (terminal 300. ; See FIG. 7).

  According to this configuration, a plurality of resonance circuits each including the plurality of capacitors 21 and the second exciting coil 30 corresponding to the capacitors 21 are obtained.

  Here, the inductance of the second exciting coil 30 is the same as the inductance of the first exciting coil 3 as described above.

  Therefore, in order to obtain the same power as that of the conventional LC resonance circuit configured by providing one capacitor and one excitation coil, the capacitance in the conventional LC resonance circuit is obtained by dividing by the number of capacitors 21. It can be seen that the obtained capacitance is sufficient.

  In this way, if the capacitance in the conventional LC resonance circuit is divided by the number of capacitors 21, the power generated by each LC resonance circuit is The electric power obtained by dividing by the number of capacitors 21. As a result, the power generated by the entire plurality of LC resonance circuits is the same as the power generated by the conventional LC resonance circuit. As a result, the same power as in the conventional configuration can be obtained.

  Next, a specific configuration of the exciting coil 3 will be described. FIG. 6 is an external view showing an example of the configuration of the exciting coil 3. This type of exciting coil 3 is used in the configuration shown in FIGS.

  As shown in FIG. 6, the exciting coil 3 is configured by winding a cable C in which a plurality of electric wires 30A covered with an insulating material are arranged in parallel. Since this type of exciting coil 3 includes a plurality of electric wires 30A arranged in parallel in the cable 3, the exciting coil 3 includes a plurality of electric wires 30A wound in the same winding number and winding direction as the winding number and winding direction of the cable C. Each of the plurality of electric wires 30 </ b> A wound in this way constitutes the second exciting coil 30.

  And in this exciting coil 3, while the terminal 300 is provided for every some electric wire 30A in the one end part side of the cable C, the terminal P common among several electric wire 30A is provided in the other end part side of a cable. Is provided.

  According to this configuration, it is possible to easily connect the plurality of second current paths 5 led out from the first connection portion 7 to the terminal 300 of the second exciting coil 30 formed of each of the plurality of electric wires 30A. it can. Therefore, a plurality of electrically independent current paths from one end of the second exciting coil 30 to the first connection portion 7 can be easily formed.

  Here, an example of this type of exciting coil 3 is an exciting coil formed by winding a cable in which a plurality of litz wires are arranged in parallel. This type of exciting coil is called a so-called litz wire coil, and one litz wire coil includes a plurality of second exciting coils 30 made of litz wire.

  FIG. 7 is an external view showing another example of the configuration of the exciting coil 3. This type of exciting coil 3 is used in the configuration shown in FIG.

  As shown in FIG. 7, the exciting coil 3 is configured by winding a cable C in which a plurality of electric wires 30A covered with an insulating material are arranged in parallel. Since this type of exciting coil 3 includes a plurality of electric wires 30A arranged in parallel in the cable 3, the exciting coil 3 includes a plurality of electric wires 30A wound in the same winding number and winding direction as the winding number and winding direction of the cable C. Each of the plurality of electric wires 30 </ b> A wound in this way constitutes the second exciting coil 30. And in the both ends of the cable C, the terminal 300 is provided for every some electric wire 30A.

  According to this configuration, with respect to one end of the second exciting coil 30 formed of each of the plurality of electric wires 30A, a plurality of current paths (for example, the second connection) derived from a certain connection portion (for example, the first connection portion 7). The current path 5) can be easily connected. Furthermore, a plurality of current paths (for example, the fifth current path 17) derived from other connection portions (for example, the third connection portion 15) can be easily connected to the other end of the second exciting coil 30. Can do.

  Therefore, a plurality of electrically independent current paths from a certain connecting portion (for example, the first connecting portion 7) to the other connecting portion (for example, the third connecting portion 15) through the second exciting coil 30 can be easily made. Can be formed.

DESCRIPTION OF SYMBOLS 1 Magnetic field generator 2 Switching element 3 Excitation coil (1st excitation coil)
4 1st current path 5 2nd current path 6 3rd current path 7 1st connection part 8 2nd connection part 9 detection part 10 control part 11 2nd branch current path 12 1st branch current path 13 to-be-heated body 15 3rd Connection portion 16 Fourth current path 17 Fifth current path 20 Switching element 21 Capacitor 30 Excitation coil (second excitation coil)
48 Heating device 700 First current path side terminal (first terminal)
710 Second current path side terminal (second terminal)
701 First branch current path side terminal (third terminal)
711 Second branch current path side terminal (fourth terminal)
712 5th current path side terminal (5th terminal)
A Image forming device L Power line

Claims (7)

A plurality of exciting coils that receive a current and generate a magnetic field;
A plurality of switching elements that are provided corresponding to each of the plurality of excitation coils, and that generate a current supplied to each of the plurality of excitation coils;
A plurality of first current paths provided corresponding to each of the plurality of switching elements, through which a current generated by each of the plurality of switching elements flows;
A plurality of second current paths provided corresponding to each of the plurality of exciting coils, and a current flows toward each of the plurality of exciting coils;
A plurality of first terminals to which one ends of the plurality of first current paths are respectively connected; and a plurality of second terminals to which one ends of the plurality of second current paths are respectively connected; A first connection portion that connects the plurality of first current paths and the plurality of second current paths by conducting each of the terminals and each of the plurality of second terminals; and
With
Each of the plurality of excitation coils is insulated from other excitation coils,
Each of the plurality of switching elements is insulated from other switching elements,
Each of the plurality of first current paths is insulated from the other first current paths,
Each of the plurality of second current paths is insulated from other second current paths,
Each of the plurality of first terminals is insulated from the other first terminals,
Each of the plurality of second terminals is insulated from the other second terminals,
The plurality of exciting coils are wound in the same number of turns and winding direction as the number of turns and winding direction of the cable by winding a cable in which a plurality of electric wires covered with an insulating material are arranged in parallel. It consists of each of multiple wires,
On one end portion side of the cable, a terminal connected to each of the plurality of second current paths is provided for each of the plurality of electric wires, while on the other end portion side of the cable, the terminals of the plurality of electric wires are provided. There is a common terminal between them,
It further comprises two power lines for transmitting power and a plurality of capacitors,
A plurality of series circuits composed of each of the plurality of switching elements and each of the plurality of capacitors are connected in parallel to the two power lines,
The one end side of each of the plurality of capacitors is connected to the common terminal of the plurality of exciting coils, while the other end side of each of the plurality of capacitors is connected to the plurality of first current paths. A magnetic field generator characterized by being connected to each other. A third current path provided corresponding to each of the plurality of switching elements and provided with a plurality of first branch current paths;
A fourth current path connected to the common terminal and provided with a plurality of second branch current paths corresponding to the plurality of first branch current paths;
A plurality of third terminals each connected to one end of each of the plurality of first branch current paths;
A plurality of fourth terminals connected to one end of each of the plurality of second branch current paths, and electrically connecting each of the plurality of third terminals to each of the plurality of fourth terminals. A second connecting portion that connects each of the plurality of first branch current paths and each of the plurality of second branch current paths;
A detector that detects a current value of a current flowing through one of the plurality of first branch current paths and the plurality of second branch current paths;
When at least one of the detected current values exceeds a preset current value, a control unit that stops supply of current to the plurality of switching elements;
The magnetic field generator according to claim 1, further comprising: A plurality of exciting coils that receive a current and generate a magnetic field;
A plurality of switching elements that are provided corresponding to each of the plurality of excitation coils, and that generate a current supplied to each of the plurality of excitation coils;
A plurality of first current paths provided corresponding to each of the plurality of switching elements, through which a current generated by each of the plurality of switching elements flows;
A plurality of second current paths provided corresponding to each of the plurality of exciting coils, and a current flows toward each of the plurality of exciting coils;
A plurality of first terminals to which one ends of the plurality of first current paths are respectively connected; and a plurality of second terminals to which one ends of the plurality of second current paths are respectively connected; A first connection portion that connects the plurality of first current paths and the plurality of second current paths by conducting each of the terminals and each of the plurality of second terminals; and
With
Each of the plurality of excitation coils is insulated from other excitation coils,
Each of the plurality of switching elements is insulated from other switching elements,
Each of the plurality of first current paths is insulated from the other first current paths,
Each of the plurality of second current paths is insulated from other second current paths,
Each of the plurality of first terminals is insulated from the other first terminals,
Each of the plurality of second terminals is insulated from the other second terminals,
The plurality of exciting coils are wound in the same number of turns and winding direction as the number of turns and winding direction of the cable by winding a cable in which a plurality of electric wires covered with an insulating material are arranged in parallel. It consists of each of multiple wires,
On both ends of the cable, a terminal is provided for each of the plurality of electric wires,
Each of the plurality of second current paths is connected to one end of each of the plurality of exciting coils,
A third current path provided corresponding to each of the plurality of switching elements and provided with a plurality of first branch current paths;
A plurality of fifth current paths connected to the other end of each of the plurality of exciting coils;
Wherein the third terminal of the multiple of each of the one end of the first branch current path is connected, one end of each of the plurality of fifth current path is respectively connected to the plurality of fifth terminal was provided, the A third connecting each of the plurality of first branch current paths and each of the plurality of fifth current paths by electrically connecting each of the plurality of third terminals and each of the plurality of fifth terminals. A connecting portion;
It further comprises two power lines for transmitting power and a plurality of capacitors,
A plurality of series circuits composed of each of the plurality of switching elements and each of the plurality of capacitors are connected in parallel to the two power lines,
One end of each of the plurality of capacitors, the third current path, each of said first branch current path, and through each of the plurality of fifth current path, other each of said plurality of exciting coils While the terminal on the end side is connected, the plurality of capacitors are connected to the other end side of each of the plurality of capacitors via each of the plurality of first current paths and each of the plurality of second current paths. A magnetic field generator, wherein a terminal on one end side of each of the exciting coils is connected. The first connection part is:
4. The magnetic field generator according to claim 1, wherein each of the plurality of first terminals is a drawer connector in contact with each of the plurality of second terminals. 5. The first connection part is:
One of the plurality of first terminals and the plurality of second terminals is composed of a plurality of screw terminals, and the other of the plurality of first terminals and the plurality of second terminals is the plurality of screws. The magnetic field generator according to any one of claims 1 to 3, wherein the magnetic field generator includes a screw terminal block that is a terminal attached to each of the terminals. A magnetic field generator according to any one of claims 1 to 5 is provided,
A heating device, wherein the heated object is induction-heated by the magnetic field generated in the magnetic field generation device. An image forming unit that forms a toner image representing an image on paper;
A fixing device configured to heat-fix the toner image formed on the paper;
An image forming apparatus comprising:

Images