JP5460442B2 - Power supply control device and image forming apparatus - Google Patents

Description

  The present invention relates to a power supply control device that controls power supply to a device in accordance with an operation of a power switch, and an image forming apparatus.

  In the image forming apparatus, when the power switch is turned off, it may be inconvenient if the power supply to the image forming apparatus is immediately cut off.

  For example, in an image forming apparatus equipped with a hard disk for storing image data or the like, if the power switch is turned off while the hard disk is being accessed and power supply is interrupted immediately, the stored data is destroyed, and then There is a possibility that it cannot be read.

  Therefore, for example, Patent Document 1 proposes an image forming apparatus including a circuit that maintains power supply for a predetermined time without immediately interrupting power supply to the image forming apparatus even when the power switch is turned off. Yes. In this image forming apparatus, even when the power switch for connecting the power supply line from the commercial power source to the image forming apparatus is turned off, the power supply to the image forming apparatus is maintained by the relay connected in parallel with the power switch. As shown, the circuit is configured.

  In addition to the power switch, a switch for detecting the on / off state of the power switch is provided in conjunction with the power switch, and the detection switch is connected to the control unit of the image forming apparatus. When the control unit detects that the detection switch is turned off, the control unit stops the process being executed in the image forming apparatus and makes a transition to a state where the power supply can be shut off. Then, after the power supply can be cut off, the relay holding the power supply is turned off to cut off the power supply to the image forming apparatus.

  As described above, the image forming apparatus disclosed in Patent Document 1 realizes that the power supply to the image forming apparatus is maintained for a predetermined time without immediately interrupting the power supply to the image forming apparatus even when the power switch is turned off. Yes.

Japanese Patent Laid-Open No. 08-202233

  By the way, the power switch that connects the power supply path to the power supply unit of the image forming apparatus has a contact point that can withstand a large current for operating the image forming apparatus, for example, a large current using silver or a silver alloy. It is required to use a contact for the service.

  On the other hand, since the detection switch for detecting the on / off state of the power switch is not a power supply path, it is not necessary to flow a large current. Therefore, it is desirable to suppress the current flowing through the detection switch to a very small current and reduce the power consumption in the image forming apparatus. The detection switch is required to use a contact corresponding to a minute current, for example, a contact for minute current subjected to Au (gold) plating.

  For this reason, an image forming apparatus that requires both a power switch having a large current contact and a detection switch having a minute current contact has the following problems.

  For example, when a dedicated power switch in which the power switch and the detection switch are mounted in the same package is used, it is more expensive than a general-purpose large-current dedicated power switch or a micro-current dedicated detection switch. The cost of the image forming apparatus is increased.

  In addition, when the power switch and the detection switch are individually arranged in the image forming apparatus and a mechanical link mechanism is provided so that these two switches operate in synchronization, the cost increases due to the link mechanism itself. The arrangement of the link mechanism prevents the device from being downsized.

In view of such a situation, the present invention uses a power switch having a contact point for large current to supply power to the power source of the image forming apparatus and shut off the power supply, and to turn on / off the power switch with a small current. an object of the present invention and the detection child.

To solve the above problems, the present invention is configured as follows.

(1) A power switch that switches between an on state in which a power supply path from a commercial power source to a power supply device is connected and an off state in which the power supply path from the commercial power source to the power supply device is cut off, and the power switch are provided in parallel. The relay is controlled to be short-circuited or opened based on a detection circuit that detects the ON / OFF state of the power switch, and a detection signal generated by the detection circuit. Control means, and the power switch includes a first switch and a second switch that is linked to the first switch, and the first switch and the second switch are connected in series. The other end of the first switch is connected to the commercial power supply, the other end of the second switch is connected to the power supply device, and the first switch and the second switch Connection point, the power supply control apparatus characterized by being connected to the detection circuit.
(2) An image forming apparatus having means for forming an image on a transfer material, wherein the power supply control device according to (1) is provided as means for controlling power supply of the image forming apparatus. An image forming apparatus.

  According to the present invention, the power supply control device uses an inexpensive high-current power switch to supply power to the power supply of the image forming apparatus and shut off the power supply, and that the power switch is turned on / off. It is possible to detect with a minute current. As a result, it is possible to reduce the power consumption of the image forming apparatus and the cost of the power switch.

Schematic sectional view showing the overall configuration of the image forming apparatus Block diagram of control system of image forming apparatus Block diagram of power supply unit of image forming apparatus Schematic block diagram of power control related to image forming apparatus Schematic configuration diagram of a commercial power input unit in the power unit of the image forming apparatus Current waveform diagram when the power switch of the image forming device is turned on Schematic configuration diagram of the detection circuit Waveform diagram of the detection signal in the detection circuit Control flowchart in this embodiment

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to embodiments.

[First Embodiment]
Hereinafter, an image forming apparatus according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic cross-sectional view illustrating the overall configuration of the image forming apparatus according to the present exemplary embodiment. The image forming apparatus according to this embodiment is an electrophotographic color copying machine in which a plurality of image forming units are arranged in parallel and an intermediate transfer method is adopted.

  In FIG. 1, the image forming apparatus includes an image reading unit 1R and an image output unit 1P. The image reading unit 1R optically reads a document image, converts it into an electrical signal, and transmits it to the image output unit 1P. The image output unit 1P includes four image forming units 10 (10a to 10d) arranged in parallel, a paper feeding unit 20, an intermediate transfer unit 30, a fixing unit 40, cleaning units 50 and 70, a photo sensor 60, and a control unit 80. Have.

  Hereinafter, each unit will be described in detail.

  Each image forming unit 10 (10a to 10d) is divided into yellow, cyan, magenta, and black colors, and the inside thereof has the same configuration. In each image forming unit 10, a photosensitive drum 11 of a drum-shaped electrophotographic photosensitive member, which is a first image carrier, is rotatably supported and driven to rotate in the arrow direction. In each image forming unit 10, a primary charger 12, an optical system 13, a folding mirror 16, a developing device 14, and a cleaning device 15 are arranged in the rotation direction so as to face the outer peripheral surface of the photosensitive drum 11. .

  The primary charger 12 applies a uniform charge amount to the surface of the photosensitive drum 11. Then, the light beam (for example, a laser beam) modulated by the optical system 13 in accordance with the recording image signal from the image reading unit 1R is exposed on the photoconductor drum 11 through the folding mirror 16, thereby causing the photoconductor drum 11 to be exposed. An electrostatic latent image is formed thereon.

  Next, the electrostatic latent image is visualized by the developing devices 14 (14a to 14d) each containing developer of four colors such as yellow, cyan, magenta, and black (hereinafter referred to as “toner”). . The visualized visible image rotates in the direction of arrow B in the image transfer areas Ta to Td, and is transferred to the intermediate transfer belt 31 of the belt-like intermediate transfer member that is the second image carrier.

  On the downstream side of the image transfer areas Ta to Td, the cleaning device 15 cleans the drum surface by scraping off the toner that is not transferred to the intermediate transfer belt 31 and remains on the photosensitive drum 11. By the process described above, image formation with each toner is sequentially performed.

  The paper feeding unit 20 is a cassette 21 for storing the transfer material P, a pickup roller 22 for feeding the transfer material P from the cassette 21 one by one, and a transport material P for further transporting the transfer material P sent from the pickup roller 22. A paper feed roller pair 23 and a paper feed guide 24 are provided. The registration roller 25 sends the transfer material P to the secondary transfer region Te in accordance with the image formation timing of each image forming unit.

  Next, the intermediate transfer unit 30 will be described.

  The intermediate transfer belt 31 is rotationally driven by a pulse motor (not shown), a driving roller 32 that transmits driving to the intermediate transfer belt 31, a driven roller 33 that is driven by the rotation of the intermediate transfer belt 31, and a secondary transfer counter. It is stretched around the roller 34. As a result, a primary transfer plane A is formed between the driving roller 32 and the driven roller 33. The driven roller 33 also has a function as a tension roller that applies an appropriate tension to the intermediate transfer belt 31 by urging a spring (not shown).

  A primary transfer charger 35 is disposed on the back side of the intermediate transfer belt 31 in the primary transfer regions Ta to Td where the photosensitive drums 11 and the intermediate transfer belt 31 face each other. A secondary transfer roller 36 is disposed to face the secondary transfer counter roller 34, and a secondary transfer region Te is formed by a nip with the intermediate transfer belt 31. The secondary transfer roller 36 is pressed against the intermediate transfer belt 31 with an appropriate pressure.

  A cleaning unit 50 for cleaning the image forming surface of the intermediate transfer belt 31 is disposed downstream of the secondary transfer region Te of the intermediate transfer belt 31. The cleaning unit 50 includes a cleaning blade 51 for removing toner on the intermediate transfer belt 31 and a waste toner box 52 for storing waste toner. On the back side of the intermediate transfer belt 31, a cleaning blade 70 and a pulse motor (not shown) for attaching and detaching the cleaning blade 70 from the intermediate transfer belt 31 are provided. The cleaning blade 70 is also for removing toner on the intermediate transfer belt 31.

  The fixing unit 40 includes a fixing belt 41a having heating means such as an IH coil (not shown), and a pressure belt 41b that pressurizes the fixing belt 41a (this belt may also have a heat source). The fixing belt 41a and the pressure belt 41b can be separated by a pressure release unit (not shown).

  Further, the fixing unit 40 includes a conveyance guide 43 for guiding the transfer material P to the nip portion between the fixing belt 41a and the pressure belt 41b, and fixing heat insulating covers 46 and 47 for confining the heat of the fixing unit. Yes.

  The transfer material P discharged from the nip portion is led out of the apparatus by the inner discharge roller 44 and the outer discharge roller 45 and stacked on the discharge tray 48.

  Next, the operation of the image forming apparatus having the above configuration will be described.

  When an image forming operation start signal is issued from a CPU 101a to be described later, the image forming apparatus starts a paper feeding operation from the paper feed stage.

  In FIG. 1, first, the transfer material P is sent out one by one from the cassette 21 by the pickup roller 22. The transfer material P is guided between the paper feed guides 24 by the paper feed roller pair 23 and conveyed to the registration rollers 25. At that time, the registration roller 25 is stopped, and the leading edge of the transfer material P hits the nip portion. Thereafter, the registration roller 25 starts rotating in accordance with the timing at which the image forming unit starts image formation. The rotation timing is set so that the front end portion of the transfer material P and the front end portion of the toner image transferred from the image forming portion onto the intermediate transfer belt 31 coincide with each other in the secondary transfer region Te. Yes.

  When the image forming operation start signal is issued, the toner image formed on the photosensitive drum 11d is transferred by the primary transfer charger 35d to the image forming unit 10d at the uppermost stream of the intermediate transfer belt 31. The toner image is transferred to the intermediate transfer belt 31 in the next transfer area Td. The transferred toner image is conveyed to the next primary transfer region Tc. In this case, image formation is performed with a delay by the time during which the toner image is conveyed between the image forming portions, and the next toner image is transferred by aligning the resist on the previous image. Thereafter, the same process is repeated, and as a result, four color toner images are transferred onto the intermediate transfer belt 31.

  When the transfer material P is sent to the secondary transfer region Te and comes into contact with the intermediate transfer belt 31, a high voltage is applied to the secondary transfer roller 36 in accordance with the passing timing of the transfer material P, and the upper surface of the intermediate transfer belt 31. The four-color toner images formed in the above are transferred onto the surface of the transfer material P. Thereafter, the transfer material P is accurately fed to the nip portion of the fixing belt by the conveyance guide 43. The toner image is fixed on the surface of the transfer material P by the heat of the fixing belt 41 a and the pressure belt 41 b and the pressure of the nip portion. Thereafter, the transfer material P is transported by the inner paper discharge roller 44 and the outer paper discharge roller 45, and the transfer material P is discharged outside the apparatus and stacked on the paper discharge tray 48.

  Next, a control system of the image forming apparatus will be described.

  FIG. 2 is a block diagram of a control system of the image forming apparatus according to this embodiment. The image forming apparatus is comprehensively controlled by the system controller 101. The system controller 101 mainly plays a role of driving each load in the image forming apparatus, collecting and analyzing information of sensors, and exchanging data with the operation unit 102 which is a user interface. The system controller 101 is mounted with a CPU 101a. The CPU 101a executes various processes related to a predetermined image forming sequence based on a program stored in the ROM 101b installed in the system controller 101. The system controller 101 is also equipped with a RAM 101c for temporarily or permanently storing data when the CPU 101a performs processing. The RAM 101c stores, for example, a high voltage set value for the high voltage control unit 105, various data, image formation command information from the operation unit 102, and the like.

  In addition to acquiring information such as a copy magnification and a density setting value input by the user, the operation unit 102 notifies the user of the state of the image forming apparatus, for example, whether the number of images formed or whether images are being formed. It is also used to display information, the occurrence of jams and their locations.

  At various locations inside the image forming apparatus, DC loads such as a motor and a clutch / solenoid, and sensors such as a photo interrupter and a micro power switch are arranged. In other words, the transfer material is conveyed and each unit is driven by appropriately driving the motor and each DC load, and various sensors monitor the operation. Therefore, the system controller 101 causes the motor control unit 107 to control each motor based on signals from the various sensors 109, and at the same time, causes the DC load control unit 108 to operate the clutch / solenoid to smoothly perform the image forming operation. Advance. Further, the system controller 101 sends various high-voltage control signals to the high-voltage control unit 105, thereby applying appropriate high voltages to the various chargers constituting the high-voltage unit 106.

  The fixing unit 40 incorporates a fixing heater 111 for heating the fixing belt 41 a, and the heater is on / off controlled by the AC driver 110. The fixing belt 41a is provided with a thermistor 104 for measuring the temperature. The resistance value change of the thermistor 104 corresponding to the temperature change of the fixing belt 41a is converted into a voltage value by the A / D 103, and then input to the system controller 101 as a digital value indicating the converted value of the temperature data of the fixing belt 41a. . Based on this temperature data, the system controller 101 controls the AC driver 110 described above to adjust the temperature of the fixing heater 111.

  A hard disk 112 is connected to the system controller 101. The system controller 101 stores the image data transmitted from the image reading unit 1R in the hard disk 112, reads out the data stored in the hard disk 112 according to a user instruction from the operation unit 102, and performs printing or the like.

  Next, the power supply unit of the image forming apparatus will be described with reference to FIG.

  FIG. 3 is a block diagram of the power supply unit of the image forming apparatus according to the present exemplary embodiment. In FIG. 3, reference numeral 201 denotes a power supply mounted on the image forming apparatus. When commercial power is input to the power source 201, a voltage of 12V is generated, and this voltage of 12V is supplied to the system controller 101 to start the system controller.

  When activated, the system controller 101 outputs a remote signal Sig1 to the power source 201. When the remote signal Sig1 is input, the power supply 201 outputs a voltage of 24V. The voltage 24V is supplied to various control units such as the high-voltage control unit 105 and the motor control unit 107 shown in FIG. 2 in addition to the system controller 101, so that the DC load in the apparatus can be driven.

  Next, the power switch for connecting the power supply path to the power source of the image forming apparatus and the detection of the on / off state of the power switch will be described with reference to FIG.

  FIG. 4 is a schematic block diagram of the power supply control relationship of the image forming apparatus. In FIG. 4, reference numeral 301 denotes a power switch, which is turned on / off by the user. Reference numeral 302 denotes a relay, which is configured to be connected in parallel with the power switch 301 and is controlled to be short-circuited or opened by the system controller 101.

  Then, even when the power switch 301 is turned off by the user, the image forming apparatus maintains the power supply from the commercial power supply by short-circuiting the relay 302 so that the power supply to the image forming apparatus is not immediately interrupted. Supply control is performed. For example, if the power supply is suddenly shut down during access to the hard disk 112 shown in FIG. 2, the contents of the hard disk may be damaged. Therefore, power is supplied only for a predetermined time until the hard disk access is completed. Is retained.

  A circuit configuration for holding power supply to the image forming apparatus will be described with reference to FIG.

  Even when the power switch is turned off, the image forming apparatus maintains power supply to the power supply 201 of the image forming apparatus by setting the relay 302 to a short-circuit state based on the control signal Sig2 from the system controller 101.

  The on / off state of the power switch 301 is detected by the detection circuit 202, and the system controller 101 constantly monitors the detection signal Sig3 transmitted from the detection circuit 202 and notifying the on / off state of the power switch 301. .

  When the system controller 101 detects that the power switch 301 is turned off by the detection signal Sig3, the system controller 101 ends the access processing to the hard disk 112 and shifts to a state where the power can be turned off. After shifting to a state where the power can be turned off, the system controller 101 changes the control signal Sig2 so as to open the relay 302, and interrupts the power supply to the image forming apparatus.

  The power switch 301 has two switches: a first switch 301a for connecting or blocking between the terminal 1 and the terminal 2, and a second switch 301b for connecting or blocking between the terminal 3 and the terminal 4. It is a power switch which has. These two switches are mounted in the same package, and the user can operate the switch 301a. The switch 301b is turned on / off almost simultaneously with the user's operation of the switch 301a. The power switch 301 has only a large current contact. Generally, silver or a silver alloy is used for the contact for high current, and silver is also used for the contact in the present embodiment. The contact using silver or silver alloy is likely to combine with sulfur in the air depending on aging and the surrounding environment to form a sulfide film such as silver sulfide on the contact surface, resulting in increased contact resistance, Problems that lead to poor contact occur. However, the sulfide film on the contact surface can be destroyed by a large rush current that flows when the contact is closed.

  However, when the value of the current flowing through the contact is very small, the destruction effect cannot be expected. Therefore, even if the power switch 301 is operated to be turned on, the sulfide film on the contact surface is not broken, and the contact portion remains in a non-conductive state due to poor contact, and there is a possibility that power supply to the power supply 201 may not be performed. Therefore, it is not desirable to allow only a very small current to flow through a power switch having a large current contact.

  On the other hand, it is not preferable to flow a large current through the detection circuit 202 that detects the on / off state of the power switch. This is because the on / off state of the power switch can be detected with a very small current, and the more current that flows through the detection circuit 202, the more wasteful current consumption will be generated, hindering the reduction in power consumption of the apparatus. Because it becomes.

  Therefore, in this embodiment, a power switch circuit that can destroy a sulfide film formed on the contact surface of the power switch 301 while keeping the current value flowing through the detection circuit 202 minute is configured as follows. doing.

  First, the circuit configuration will be described.

  In FIG. 4, one end (terminal 2 side) of the switch 301a and one end (terminal 3 side) of the switch 301b are connected in series. Then, the other end (terminal 1 side) of the switch 301a is connected to a commercial power source, and the other end (terminal 4 side) of the switch 301b is connected to the power source 201 of the image forming apparatus. Further, a connection point between the switch 301 a and the switch 301 b (a connection point between the terminal 2 and the terminal 3) is connected to the detection circuit 202.

  Next, circuit operation will be described.

  When the power switch 301 is off, the power supply 201, the detection circuit 202, the system controller 101, etc. are all in a non-energized state, so the relay 302 is also in an off state (open state). When the power switch 301 is turned on, the two switches 301a and 301b are turned on, and a current flows from the commercial power source to the power source 201 via the switches 301a and 301b. As will be described later, even if a sulfide film is generated at the contact point of the power switch 301, the current that flows when the power switch 301 is turned on is sufficient to destroy the current.

  FIG. 5 is a schematic configuration diagram of a commercial power input unit in the power unit of the image forming apparatus according to the present exemplary embodiment. As shown in FIG. 5, the commercial power input unit of the power source 201 includes a diode bridge 801 for full-wave rectification of the commercial power, and a smoothing capacitor 802 at the subsequent stage. The capacity is 680 μF. When the power switch 301 is turned on, the smoothing capacitor 802 is charged from the commercial power source via the power switch 301, so that a large current for charging flows to the contact of the power switch 301.

  FIG. 6 is a diagram illustrating an example of a waveform of a current flowing through the power switch 301 when the power switch 301 is turned on in the present embodiment. From FIG. 6, it can be seen that a current of about 80 A (ampere) at the peak value flows through the contact point of the power switch 301. In order to destroy the silver sulfide film that is the contact material for high current of the power switch 301, it is sufficient to pass a current of about several A.

  As described above, by connecting the power switch 301 and the power source 201 to the circuit configuration shown in FIG. 4, even if a sulfide film is formed on the contact surface of the power switch 301, it can be destroyed. Yes.

  In this embodiment, the detection circuit 202 is configured as shown in FIG. In FIG. 7, a resistor 501 is a resistor that limits the current flowing through the detection circuit 202. In this embodiment, the resistance value is 100 kΩ.

Therefore, the current I flowing from the connection point of the switch 301a and the switch 301b to the detection circuit 202 and the approximate value of the power loss in the detection circuit 202 are as follows when the commercial power source is 100V.
Current I = V (voltage) / R (resistance)
= 100 (V) / 100 (kΩ)
= 1 (mA)
Power loss Pw = V (voltage) x I (current)
= 100 (V) x 1 (mA)
= 0.1W
In this embodiment, since the current required for the operation of the photocoupler 502 is about 1 mA, the resistance 501 has the above resistance value.

  Since the current flowing from the connection point of the switch 301a and the switch 301b to the detection circuit 202 is only 1 mA, this small current alone does not have the ability to break the sulfide film formed on the contact point of the power switch 301. That is, a large current that can destroy the oxide film does not flow to the detection circuit 202.

Since the power loss always occurs when the power switch 301 is on, it is desirable to reduce such power loss as much as possible. For example, the power loss Pw2 when the current value flowing through the detection circuit 202 is set to 1A in an attempt to destroy the sulfide film formed on the contact point of the power switch 301 also by the current flowing through the detection circuit 202 is the power loss Pw2. = 100 (V) x 1 (A) = 100W
And a very large power loss occurs, which is even more undesirable.

  The detection signal Sig3 transmitted from the detection circuit 202 to the system controller changes as follows according to the state of the power switch 301.

  When the power switch 301 is on, a current flows through the photocoupler 502 in the detection circuit 202 via the connection point between the switch 301a and the switch 301b. As a result, as shown in FIG. 8A, the detection signal Sig3 becomes a low level signal except in the vicinity of the zero cross where the AC voltage of the commercial power supply becomes 0V (volt). On the other hand, at zero cross, the AC voltage is 0 V, so that no current flows through the photocoupler 502, and the detection signal Sig3 is at a high level.

  When the power switch 301 is off, no current flows through the photocoupler 502, so that the detection signal Sig3 is always a high level signal as shown in FIG. 8B. The system controller 101 determines the on / off state of the power switch 301 by receiving the detection signal Sig3 that changes in this way.

  As described above, the present embodiment has a circuit configuration that can destroy the sulfide film even if a sulfide film is formed on the contact surface of the power switch 301 while keeping the current value of the current flowing through the detection circuit 202 minute. Realized.

  FIG. 9 is a flowchart illustrating a control sequence for holding and shutting off the power supply to the power source of the image forming apparatus according to the present exemplary embodiment. The following control sequence is executed by the CPU 101a mounted on the system controller 101 based on a program stored in the ROM 101b mounted on the system controller 101.

  When the power switch 301 is turned on, the system controller 101 is activated (S701), and various settings and operations necessary for the image forming operation are sequentially started.

  Prior to these operations necessary for image formation, the system controller 101 outputs a control signal Sig2, and short-circuits the relay 302 that holds the power supply line from the commercial power supply to the power supply of the image forming apparatus (S702).

  Thus, even if the power switch 301 is turned off, the power supply from the commercial power supply can be maintained until the system controller 101 can turn off the power of the image forming apparatus.

  Then, the system controller 101 of the image forming apparatus monitors the detection signal Sig3 indicating the on / off state of the power switch 301 by polling at a constant cycle (S703).

  When the detection signal Sig3 becomes High level and it is detected that the power is turned off, the system controller 101 determines whether or not the power supply of the image forming apparatus can be immediately shut off (S704). . For example, if the system controller 101 is accessing the hard disk, the power cannot be turned off immediately, so access to the hard disk is stopped and preparations for turning off the power are made (S705).

  For example, if the access to the hard disk is completed and the power supply can be shut off (S704), the relay 302 is opened (S706). As a result, the image forming apparatus is turned off.

  As described above, according to the present invention, a power switch for an image forming apparatus is powered on and off using an inexpensive high-current power switch, and at the same time, the power switch is turned on or off. Detection can be performed with a minute current. Thereby, it is possible to reduce the power consumption of the image forming apparatus and reduce the cost of the power switch.

101 System Controller 201 Power Supply 202 Detection Circuit 301 Power Switch 302 Relay

Claims (8)

A power switch that switches between an on state that connects a power supply path from a commercial power source to a power supply device and an off state that blocks a power supply path from the commercial power source to the power supply device;
A relay provided in parallel with the power switch and controlled to a short circuit or an open state;
A detection circuit for detecting an on / off state of the power switch;
Based on the detection signal generated by the detection circuit, the control means for controlling the relay to a short circuit or an open state;
With
The power switch includes a first switch and a second switch interlocked with the first switch, and the first switch and the second switch are connected in series, and the first switch The other end is connected to the commercial power supply, the other end of the second switch is connected to the power supply device, and a connection point between the first switch and the second switch is connected to the detection circuit. A power supply control device characterized by comprising: The current flowing from the commercial power source to the power supply device via the first switch and the second switch is a current having a current value that destroys the sulfide film formed on the contact surface of the power switch,
The detection circuit includes a resistor through which a current flows from the commercial power source via a connection point between the first switch and the second switch, and a current flowing from the connection point to the detection circuit is the sulfide film. The power supply control device according to claim 1 , wherein a resistance value of the resistor is set so as to have a current value that does not destroy the power supply.   When the current from the commercial power source is detected, the detection circuit indicates a detection signal indicating that the power switch is on. When the current from the commercial power source is not detected, the power switch is off. The power supply control device according to claim 1, wherein a detection signal indicating that the power is detected is sent to the control unit. When the control means receives a detection signal indicating that the power switch is in an ON state from the detection circuit, the control means short-circuits the relay and maintains a power supply path connection between the commercial power supply and the power supply device. And
Wherein when the power supply switch from the detection circuit receives a detection signal indicating the OFF state, after the processing for turning off the power, opening the relay, the commercial power source and the power supply device 4. The power supply control device according to claim 1, wherein the power supply path is disconnected from the power supply path. Have a hard disk to record information,
The power supply control apparatus according to claim 4, wherein the process for turning off the power is a process in which the control unit completes access to the hard disk. 6. The power supply control device according to claim 1, wherein the first switch and the second switch are mounted in the same package. The power supply control device according to claim 6, wherein silver or a silver alloy is used for each contact of the first switch and the second switch. An image forming apparatus having means for forming an image on the transfer material, as a means of controlling the power supply of the image forming apparatus, further comprising a power supply control device according to any one of claims 1 to 7 An image forming apparatus.

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