JP4336318B2 - Electronic apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to various electronic apparatuses and electrophotographic image forming apparatuses.

  Electric double layer capacitors have a large capacity and are excellent in charge / discharge cycle characteristics. Therefore, backup power sources for various electronic devices, auxiliary power sources for electrophotographic image forming devices, and various other types including automobiles. In addition to being used as a battery for transport aircraft, from the viewpoint of effective use of energy, use in applications such as nighttime power storage is also being considered.

  As an auxiliary power supply apparatus using this electric double layer capacitor and an image forming apparatus using the auxiliary power supply apparatus, techniques disclosed in Patent Documents 1 to 3 are known.

  Patent Document 1 discloses that the capacitor cell is connected in series, a charger that charges the capacitor cell, and a parallel monitor that equalizes the charging voltage of each capacitor cell. It is disclosed that when any of the capacitors connected to the battery is fully charged, charging by the charger is stopped, and when the full charging voltage is interrupted, charging by the charger is performed again.

  In Patent Document 2, in FIG. 5, a main power supply device, a charger, an auxiliary power supply device, an auxiliary switch for connecting the main power supply device and the charger, and a control unit for connecting the auxiliary switch to the main power supply device and the charger. And supplying power to the charger through the auxiliary power switch from the main power supply device and charging the auxiliary power supply device with the charger.

  Patent Document 3 discloses that a capacitor is used as an auxiliary power source to shorten the rise time of the heating device and reduce the temperature change of the heating device.

Japanese Patent No. 3491875 JP 2003-257590 A JP 2003-297526 A

  By the way, in an electronic apparatus such as an electrophotographic image forming apparatus, when the apparatus is not used for a certain period of time even when the main power is turned on, the electric power is removed except for a part of a circuit such as a control system circuit. There is a so-called energy saving mode in which supply is temporarily stopped to save power.

  In such an electronic device, a power supply circuit that generates a DC power supply that is supplied from a commercial AC power supply to a control system circuit is provided, and power supply to a control system circuit that continues to supply power even in an energy saving mode is performed. This is done from the power supply circuit.

  However, the DC power supplied from such a power supply circuit in the energy saving mode has a high output of, for example, about 80% of the rated power. And it is a part of the control system circuit that should continue to supply power even in the energy saving mode, and what is required is about 30% of the rated power of the DC power supply. Therefore, maintaining a high output of about 80% of the rated power in the energy saving mode is wasteful from the viewpoint of energy saving, and further power saving is desired.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to make it possible to further save power in an energy saving mode in an electronic device or an image forming apparatus provided with a charging unit serving as an auxiliary power source composed of a capacitor or the like.

  The present invention provides a power storage unit that stores power, a predetermined load that receives power supply from the power storage unit, a charging device that charges the power storage unit, and a first power source that supplies power to the charging device using a commercial power source as a power source A circuit, a second power supply circuit that supplies power to a part of the circuit of the apparatus other than the load using the commercial power supply as power, and power in the energy saving mode of the apparatus by the first power circuit and the second power circuit The power supply means for supplying the charging power of the power storage unit to the part of the circuit, a first voltage detection circuit for detecting the charging voltage of the power storage unit, and the detection voltage is preset. And a first charging means for charging the charging unit by the charging device when the detected voltage falls below the reference value in this comparison. It is.

  The present invention viewed from another aspect includes a fixing device, a power storage unit that stores power, a first heater that heats a fixing roller of the fixing device using a commercial power source as a power source, and receives power supplied from the power storage unit, A second heater that heats the fixing roller of the fixing device; a charging device that charges the power storage unit; a first power supply circuit that supplies power to the charging device using the commercial power source as a power source; A second power supply circuit that supplies power to a part of the circuit of the apparatus other than the first and second heaters, and power supply by the first power supply circuit and the second power supply circuit is stopped in the energy saving mode of the apparatus. A power supply means for supplying charging power of the power storage unit to the part of the circuit; a first voltage detection circuit for detecting a charging voltage of the power storage unit; and comparing the detected voltage with a preset reference value First comparing means An electrophotographic image forming apparatus includes a, a first charging means for charging the charging portion by the charging apparatus when said detection voltage in this comparison is below the reference value.

  According to the present invention, it is possible to use the stored power of the power storage unit instead of the second power supply circuit for a part of the circuits that should be energized even in the energy saving mode. There is no need to output a large amount of power in the power supply circuit, and power can be saved compared to the conventional case.

  Moreover, even when the energy saving mode lasts for a long time, the battery can be automatically charged when the voltage of the charging unit decreases.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 is a longitudinal side view showing a schematic configuration of an image forming apparatus 1 that implements an electronic apparatus and an image forming apparatus of the present invention.

  As shown in FIG. 1, the image forming apparatus 1 is an electrophotographic image forming apparatus, and includes an image forming unit 1A provided at the center thereof, and a paper feeding unit 1B provided below the image forming unit 1A. And an original scanning unit 1C provided above the image forming unit 1A.

  The document scanning unit 1C includes a scanner 1C2 having a document placement table 1C1 on which a document is placed, and an automatic document feeder 1C3 provided on the document placement table 1C1. The scanner 1C2 reads a document image (image data) from a document on the document table 1C1. The automatic document feeder 1C3 is configured to send a document on the document table 1C1 and to reverse the document sent on the document table 1C1. Thereby, it is also possible to read the document image on each side of the document.

  The image forming unit 1A includes a toner image formed by an intermediate transfer belt 2 having a horizontally extending surface, and toners of colors (yellow, magenta, cyan, and black) that are juxtaposed along the extending surface and have a complementary color relationship with the color separation color. Is provided with a plurality of photoconductors 3Y, 3M, 3C, 3B and the like.

  Each of the photoconductors 3Y, 3M, 3C, and 3B is formed in a drum shape, and is provided so as to be rotatable in the same direction (counterclockwise in FIG. 1). Around each of the photoreceptors 3Y, 3M, 3C, and 3B, charging devices 4Y, 4M, 4C, and 4B that perform image forming processing in the rotation process of the photoreceptors 3Y, 3M, 3C, and 3B, a writing device 5, and development Apparatuses 6Y, 6M, 6C, and 6B, primary transfer apparatuses 7Y, 7M, 7C, and 7B and cleaning apparatuses 8Y, 8M, 8C, and 8B are arranged.

  The charging devices 4Y, 4M, 4C, and 4B uniformly charge the surfaces of the photoreceptors 3Y, 3M, 3C, and 3B.

  The writing device 5 writes light according to image information obtained from a document on the document table 1C1 by the scanner 1C2 or image information input from a computer (not shown) connected to the image forming device 1. Is emitted to each of the photoreceptors 3Y, 3M, 3C, and 3B to form an electrostatic latent image.

  The developing devices 6Y, 6M, 6C, and 6B supply toner to the electrostatic latent images formed on the surfaces of the photoreceptors 3Y, 3M, 3C, and 3B, and form toner images on the surfaces.

  The primary transfer devices 7Y, 7M, 7C, and 7B primarily transfer the toner images formed on the surfaces of the photoreceptors 3Y, 3M, 3C, and 3B to the intermediate transfer belt 2. At this time, the toner images of the photoreceptors 3Y, 3M, 3C, and 3B are superimposed on the intermediate transfer belt 2.

  The intermediate transfer belt 2 is formed so as to be able to move in the same direction at a position facing the photoreceptors 3Y, 3M, 3C, and 3B by being wound around a plurality of rollers 2A, 2B, and 2C. The roller 2A and the roller 2B form a stretched surface of the intermediate transfer belt 2. These other rollers 2C are opposed to the secondary transfer device 9 with the intermediate transfer belt 2 interposed therebetween. A cleaning device 10 for cleaning the intermediate transfer belt 2 is provided at a position facing the intermediate transfer belt 2.

  The secondary transfer device 9 includes a transfer belt 9C that is wound around the charging drive roller 9A and the driven roller 9B and is movable in the same direction as the intermediate transfer belt 2 at the secondary transfer position. The transfer belt 9C is driven to be charged. By charging with the roller 9A, the multicolor image superimposed on the intermediate transfer belt 2 or the supported single color image is transferred to the sheet.

  The sheet feeding unit 1B includes a plurality of sheet feeding cassettes 1B1 that store sheets, a plurality of sheet feeding rollers 1B2 that are arranged in a sheet conveyance path that is fed out from the sheet feeding cassette 1B1, and an upstream side of the secondary transfer position (sheet conveyance). Registration rollers 1B3 and the like positioned in the direction).

  Further, the paper feeding unit 1B includes a manual feed tray 1B4 and a feeding roller 1B5 that are provided so that a part of the wall surface of the image forming unit 1A can be turned up and down, and in addition to a conveyance path of a sheet fed out from the paper feeding cassette 1B1. The sheet placed on the manual feed tray 1B4 is fed toward the secondary transfer position. In the middle of the sheet conveyance path from the sheet feeding cassette 1B1 to the registration roller 1B3, the sheet conveyance path fed from the manual feed tray 1B4 joins, and the sheet fed from any conveyance path is registered by the registration roller 1B3. Timing is set.

  On the downstream side of the secondary transfer device (in the sheet conveyance direction), a fixing device 111 (described in detail later) that fixes the toner image on the sheet to the sheet, and a discharge unit 12 that discharges the sheet on which the toner image is fixed. Is provided.

  Further, the image forming apparatus 1 is provided with a front door (not shown) for opening the interior thereof by jamming or the like, and a capacitor device 13 (details will be described later) for supplying power to the fixing device 111. Yes. The capacitor device 13 is formed to be attachable to the image forming apparatus 1.

  The discharge unit 12 includes a conveyance path switching claw 12A that switches the sheet conveyance direction, a sheet discharge tray 12B that discharges the sheet, a reversal conveyance path 12C that reverses the front and back of the sheet by duplex printing and the like. The discharge unit 12 switches the sheet conveyance direction by the conveyance path switching claw 12A, and conveys the sheet that has passed through the fixing device 111 along the conveyance path toward the sheet discharge tray 12B or the reverse conveyance path 12C.

  In such an image forming apparatus 1, the uniformly charged photoreceptors 3Y, 3M, 3C are based on image information from a document placed on the document placement table 1C1 or image information from an external host computer. An electrostatic latent image is formed on 3B, and the electrostatic latent image is subjected to visible image processing by the developing devices 6Y, 6M, 6C, and 6B, and then the toner image is primarily transferred to the intermediate transfer belt 2.

  The toner image primarily transferred to the intermediate transfer belt 2 is secondarily transferred to the sheet fed from the sheet feeding unit 1B as it is in the case of a single color image, and is primary transferred in the case of a multicolor image. After being superimposed by repetition, secondary transfer is collectively performed on the sheet. After the secondary transfer, the unfixed image is fixed by the fixing device 111 and then fed toward the paper discharge tray 12B or reversed and fed toward the registration roller 1B3 again.

  FIG. 2 is a longitudinal side view showing a schematic configuration of the fixing device 111 provided in the image forming apparatus 1.

  As shown in FIG. 2, the fixing device 111 includes a fixing roller 21 that is a fixing member, a pressure roller 23 that is a pressure member, and a pressure unit that presses the pressure roller 23 against the fixing roller 21 with a constant pressure. (Not shown). The fixing roller 21 and the pressure roller 23 are rotationally driven by a drive mechanism (not shown).

  The fixing device 111 is provided with a total of three heating heaters, two AC heaters (reference numerals 29 and 30) and one DC heater (reference numeral 22), and a temperature detection thermistor (reference numerals 37 and 30). 38). These fixing heaters 29, 30, and 22 are disposed inside the fixing roller 21, and heat the fixing roller 21 from the inside. The thermistors 37 and 38 are in contact with the surface of the fixing roller 21 and detect the surface temperature (fixing temperature) of the fixing roller 21. The thermistor 37 is disposed in the measurement region corresponding to the heater 29 and the heater 30, and the thermistor 38 is disposed in the measurement region corresponding to the heater 22.

  The heaters 29 and 30 are main heaters (first heaters) that are turned on to heat the fixing roller 21 when the temperature of the fixing roller 21 has not reached the target temperature. Further, the heater 22 is turned on when the main power of the image forming apparatus 1 is turned on or when the image forming apparatus 1 is started up from the sleep mode (energy saving mode) for energy saving until it becomes possible to copy, that is, when the fixing device 111 is warmed up. Or is turned on when the temperature of the fixing roller 21 does not reach the target temperature during image formation, and an auxiliary heater (second heater (which becomes a predetermined load)) that heats the fixing roller 21 It is.

  In such a fixing device 111, the sheeter carrying the toner image is pressed and pressed by the fixing roller 21 and the pressing roller 23 when passing through the nip portion between the fixing roller 21 and the pressing roller 22. As a result, the toner image is fixed on the sheet.

  FIG. 3 is a circuit diagram of a power supply device provided in the image forming apparatus 1.

  First, the image forming apparatus control unit 12 will be described.

  The image forming apparatus control unit 12 includes a CPU 12a, a ROM (not shown), a RAM, a timer, an interrupt control circuit, an A / D converter, a serial controller (UART), and an input / output port.

  When the main power supply of the image forming apparatus 1 is turned on for the first time, the capacitor bank 9 is not charged, so the normally closed relay 11 (closed when not energized) is not energized. Therefore, the relay 11 is in a closed state, and AC power is supplied to a charging unit described later.

  When the main power supply is turned on and the power supply is supplied from the DC / DC converter, the image forming apparatus control unit 12 initializes the image forming apparatus control unit and peripheral circuits, and then connects the relay 11 from the port 1. A close signal “Low” is output to the open collector circuit 34. Since the transistor Tr3 of the relay drive circuit 37 is turned off by the output of the open collector circuit 34, the relay 11 is turned off and the relay contact is kept closed.

  After the image forming operation is performed by the image forming apparatus 1, the CPU 12a enters an energy saving mode in which the power of the image forming apparatus 1 is reduced when the image forming operation is not performed for a certain time. When entering the energy saving mode, the CPU 12 a outputs a signal “H” for opening the relay 11 from the port 1 to the open collector circuit 34. By the output of the open collector circuit 34, the transistor Tr3 of the relay drive circuit 37 is turned on, and the relay 11 is turned on. Although details will be described later, when the capacitor bank 9 is in the charged state, the transistor Tr2 is in the ON state, so that the transistor Tr3 is in the OFF state. Therefore, even when the CPU 12a enters the energy saving mode, the entry into the energy saving mode is postponed during charging. When charging is completed, the transistor Tr2 is turned off, the transistor Tr3 is turned on, the relay 11 is energized, and the relay 11 is opened. When the relay 11 is opened, AC power supply to a charging unit described later is stopped.

  Further, the CPU 12 a outputs a power output stop signal, “H”, from the port 5 to the DC / DC converter circuit 33 when entering the energy saving mode.

  The DC / DC converter circuit 33 stops the power supply to the image forming apparatus control unit 12, a part of the control circuit 12 c of the image forming apparatus control unit 12 and the LAN control circuit 26 in response to the “H” signal.

  When canceling the energy saving mode, the energy saving mode cancel SW 36 is turned ON. The energy saving mode cancel SW signal “Low” is input to the DC / DC converter circuit 33.

  When the energy saving mode release SW signal “Low” is input, the DC / DC converter circuit 33 supplies power to the image forming apparatus control unit 12, a part of the control circuit 12 c of the image forming apparatus control unit 12, and the LAN control circuit 26. Supply. Thereby, the energy saving mode is canceled.

  A LAN control circuit 26 is connected to the image forming apparatus control unit 12 and is supplied with power by the capacitor cell 9q in the energy saving mode.

  The LAN control circuit 26 controls the LAN to which the image forming apparatus 1 is connected. When the LAN signal is received from an external computer or the like in the energy saving mode, the LAN control circuit 26 outputs an energy saving mode release signal “Low” to the DC / DC converter circuit 33. Output to. When the energy saving mode release signal “Low” is input, the DC / DC converter circuit 33 supplies power to the image forming apparatus control unit 12, some control circuits 12 c of the image forming apparatus control unit 12, and the LAN control circuit 26. Supply.

  The voltage of the capacitor cell 9q is set lower than Vcc, and the main power supply is turned on and the Vcc power is supplied to the LAN interface circuit 26 and a part of the control circuit 12c of the image forming apparatus control unit 12. The power is not supplied from the capacitor cell 9q to the LAN interface circuit 26 and a part of the control circuit 12c of the image forming apparatus control unit 12.

  Next, the point that the power stored in the capacitor bank 9 is used for the memory of the image forming apparatus 1 will be described.

  When the main power supply of the image forming apparatus 1 is normally turned on, power is supplied to the memory 25 by the power supply circuit 24. The memory 25 is backed up by the capacitor cell 9r in the energy saving mode or when the main power supply is OFF. The memory 25 is an SRAM, SDRAM, DDR or the like.

  Next, an operation in which the image forming apparatus control unit 12 discharges the electric power stored in the capacitor bank 9 will be described.

  The CPU 12 a detects the overheated portion temperature of the fixing device 111 by the thermistor 38 provided in the fixing device 111. When the temperature of the thermistor 38 is lower than a preset temperature, the CPU 12a communicates with the constant current and constant power charging voltage generation circuit 10 via the UART 28, and when the voltage of the capacitor bank 9 is in a state where it can be discharged. The signal “H” is output from the port 2 to the circuit 20 that drives the relay 19 a of the discharge circuit 19, and then the signal “H” that turns on the FET 19 a is output from the port 3 to the buffer circuit 21. The relay 19a and the FET 9b are turned on to supply power to the fixing heater 22 connected to the capacitor bank 9.

  When the temperature of the thermistor 38 is higher than a preset temperature, a "Low" signal is output from the port 2 of the CPU 12a to the circuit 20 that drives the relay 19a of the discharge circuit 19, and then the FET 19a is turned off from the port 3. The signal “Low” is output to the buffer circuit 21. Therefore, the power supply to the fixing heater 22 is stopped.

  Next, a control circuit that detects the charging voltage of the capacitor bank 9 and controls the relay 11 that supplies AC power to a charging unit described later will be described.

  In the charging voltage detection circuit 31, the comparator 42, the resistor R9, and the resistor R8 constitute a hysteresis circuit. The charging voltage of the capacitor cell 9r is input to the inverting input terminal of the comparator 42.

  Further, a reference voltage for detecting a threshold voltage of the charging voltage of the capacitor cell 9r is created by a circuit including a voltage in which the capacitor cells 9r, 9q, and 9p are connected in series, a resistor R7, and a Zener diode ZD2. The output of the reference voltage circuit 39 is input to the non-inverting input terminal of the comparator 42 via the resistor R8.

  When the inverting input terminal voltage (capacitor 9r voltage) of the comparator becomes higher than the voltage of the reference voltage circuit 39, the charging voltage detection circuit 31 having the hysteresis characteristic outputs a signal “Low” to the transistor Tr2, and the transistor Tr2 is turned off. It becomes. The collector output of the transistor Tr2 is connected to the base of the transistor Tr3.

  In this state, when the power of the DC / DC converter is supplied to the image forming apparatus control unit 12 and the LAN control circuit 26, a signal “Low” for closing the relay 11 is opened from the port 1 of the image forming apparatus control unit 12. Since the signal is output to the collector circuit 34, the closing signal is given priority.

  In the case of the energy saving mode in which the power of the DC / DC converter 33 is not supplied to the image forming apparatus control unit 12 and the LAN control circuit 26, no signal is output from the port 1 of the image forming apparatus control unit 12. Tr3 is turned ON. When the transistor Tr3 is turned on, the normally closed relay 11 is energized, and the contact of the relay 11 is opened.

  When the inverting input terminal voltage (capacitor 9r voltage) of the comparator 42 becomes lower than the voltage of the reference voltage circuit 39, the charging voltage detection circuit 31 having the hysteresis characteristic outputs a signal to close the relay 11, "H", to the transistor Tr2. To do. Thereby, the transistor Tr2 is turned on, the transistor Tr3 is turned off, the relay 11 is deenergized, the contact of the relay 11 is closed, and charging is started.

  Next, the charging circuit of the charging unit that charges the capacitor bank 9 and the operation thereof will be described.

  The AC input from the AC power source AC is connected to the relay 11 that is closed when not energized (normally closed) via the filter 1, and the output of the relay 11 is connected to the full-wave rectifier circuit 2 and full-wave rectified. The output is connected to the smoothing capacitor C1. The smoothing capacitor C1 removes ripple components and the like of the output of the full-wave rectifier circuit 2.

  A primary coil 3a of the high-frequency transformer 3 is connected in parallel with the smoothing capacitor C1 on the DC output side of the full-wave rectifier circuit 2, and an FET 6a is connected in series as a switching means to the primary coil 3a.

  In the switching circuit 6 constituted by the FET 6a, when the FET 6a is switched (ON / OFF operation) by a PWM signal output from a switching regulator IC 13 described later, a switching current flows through the primary coil 3a. A switch voltage is induced in the secondary coil 3b of the transformer 3 by the switch current on the primary side. If the conduction period of the switching frequency is changed, the output voltage can be controlled.

  Diodes D1 and D2 are connected to the secondary coil 3b of the transformer 3 as the rectifier circuit 4. The switching voltage is rectified by the rectifier circuit 4, smoothed by the choke coil 5 and the capacitor C2, and converted into a DC output. This direct current output is supplied via the diode D3 to the capacitor bank 9 in which capacitor cells (9a or less) are connected in series, and the individual capacitor cells of the capacitor bank 9 are charged.

  The capacitor bank 9 of this example is connected in series with 18 capacitor cells (electric double layer capacitor cells) that become 2.5 V when fully charged. Therefore, when 18 capacitor cells are fully charged, a voltage of 45 V is stored.

  Next, the operation of the switching regulator IC 13 that generates the PWM signal will be described.

  The switching regulator IC 13 starts operation by supplying power from a circuit composed of a resistor R1, a capacitor C3, and a Zener diode ZD1 to the DC output of the full-wave rectifier circuit 2, and the auxiliary winding 7 and the diode D4 Operation continues with the configured auxiliary power supply.

  The frequency that becomes the PWM signal is determined by the resistance value of the circuit 15 composed of the resistor and the condancer and the capacitance of the capacitor.

  The switching regulator IC 13 includes a voltage-pulse width conversion circuit for modulating the pulse width in accordance with the feedback voltage 23 of the output voltage of the photocoupler PC1 of the feedback voltage detection circuit 14. The pulse width changes according to the feedback voltage 23, and the PWM signal is input to the gate of the FET 6a. By switching the primary coil 3a of the transformer 3 by the FET 6a, the output voltage of the secondary coil 3b of the transformer 3 is changed. Different voltages can be generated.

  The feedback to the feedback voltage detection circuit 14 is supplied to the base of the transistor Tr1 constituting the voltage-current conversion circuit 18 that converts the voltage generated by the constant current and constant power charging voltage generation circuit 10 to convert the voltage into a current. Feedback is provided by the photocoupler PC1 connected to the emitter of Tr1.

  Next, the capacitor bank 9 and the charging voltage detection circuit 16 of the capacitor bank 9 will be described.

  That is, the inter-terminal voltage of the capacitor bank 9 is divided by the resistors R2 and R3, and the voltage is input to the constant current and constant power charging voltage generation circuit 10.

  Next, detection of the charging current of the capacitor bank 9 by the constant current and constant power charging voltage generation circuit 10 will be described.

  The charging current of the capacitor bank 9 is detected by detecting the voltage across the terminals of the resistor R4 connected in series with the capacitor bank 9.

  Next, the operation of the bypass circuit 17 that detects the full charge of each capacitor cell and equalizes the charging voltage by bypassing the charging current will be briefly described.

  The bypass circuit 17a in FIG. 3 is connected in parallel between the terminals of the capacitor cell 9a. When the capacitor cell 9a is charged to a predetermined voltage, a bypass circuit (each bypass circuit of the bypass circuit 17 is represented by a bypass circuit corresponding to the capacitor cell 9a and is given a reference numeral of the bypass circuit 17a). Bypass charging current. The other bypass circuits perform the same operation, and the charging voltages of the capacitor cells are equalized.

  The bypass circuit 17 outputs a capacitor cell full charge signal 41 to the constant current and constant power charge voltage generation circuit 10 when any capacitor cell bypass circuit operates. When all the bypass circuits are operated, the charging completion signal 40 is output to the constant current and constant power charging voltage generation circuit 10.

  Next, the constant current and constant power charging voltage generation circuit 10 detects the charging voltage of the entire capacitor cell (capacitor bank 9), the detection of the charging current, and the operation of the bypass circuit, and performs constant current charging and constant power charging. The point will be described.

  The constant current and constant power charging voltage generation circuit 10 includes a CPU, ROM, RAM, termer, interrupt control circuit, A / D converter, serial controller (UART), D / A converter, and input / output ports (not shown). ing.

  The constant current and constant power charge voltage generation circuit 10 charges the capacitor cell via the image forming apparatus control unit 12 and the UART 27 which is a serial communication unit.

  The constant current and constant power charging voltage generation circuit 10 detects the voltage across the terminals of the capacitor bank 9 based on the output of the charging voltage detection circuit 16.

  When the voltage between the terminals of the capacitor bank 9 is lower than a preset value, the voltage for the preset constant current charge is set to the voltage / voltage from the D / A terminal of the constant current and constant power charge voltage generation circuit 10. This is output to the operational amplifier 29 of the current conversion circuit 18.

  Current detection for constant current charging is detected by the voltage across the terminals of the resistor R4 connected in series with the capacitor bank 9. The constant current and constant power charge voltage generation circuit 10 sequentially detects this inter-terminal voltage, and a voltage for making a preset constant current charge is supplied from the D / A terminal of the constant current and constant power charge voltage generation circuit 10. Output to the operational amplifier 29 of the voltage / current conversion circuit 18.

  The analog voltage output from the D / A terminal of the constant current and constant power charging voltage generation circuit 10 may use a table in which the relationship between the terminal voltage of the resistor R4 and the analog voltage to be output is registered in advance. It may be calculated by calculation.

  The analog voltage output from the D / A terminal of the constant current and constant power charge voltage generation circuit 10 is input to the operational amplifier 29 of the voltage / current conversion circuit 18, and the transistor Tr1 causes the photocoupler PC1 to input a constant current and a constant current. A current corresponding to the voltage output from the D / A terminal of the constant power charging voltage generation circuit 10 flows and is fed back to the feedback voltage detection circuit 14. The width of the PWM signal is controlled by this feedback voltage, and constant current charging is performed. PWM signal is output from the switching regulator IC 13 to the gate of the FET 6a.

  When the inter-terminal voltage of the capacitor bank 9 becomes equal to or higher than a preset value, the constant current and constant power charging voltage generation circuit 10 performs the constant power charging, as described above, the charging current of the capacitor bank 9 and the capacitor The inter-terminal voltage of the bank 9 is detected, and a preset voltage for performing constant power charging is calculated and determined from the detected charging current and charging voltage.

  Then, this voltage is outputted from the D / A terminal of the constant current and constant power charging voltage generation circuit 10. As described above, the analog voltage output from the D / A terminal of the constant current and constant power charge voltage generation circuit 10 is input to the operational amplifier 29 of the voltage / current conversion circuit 18, and is input to the photocoupler PC1 by the transistor Tr1. , A current corresponding to the voltage output from the D / A terminal of the constant current and constant power charge voltage generation circuit 10 flows and is fed back to the feedback voltage detection circuit 14, and the width of the PWM signal is controlled by this feedback voltage. A PWM signal for constant power charging is output from the switching regulator IC 13 to the FET 6a.

  The constant current and constant power charging voltage generation circuit 10 sequentially detects the voltage between the terminals of the capacitor bank 9 and the charging current of the capacitor bank 9, and sets a voltage for performing preset constant power charging as D / A. Output from the terminal.

  Next, the constant current and constant power charging voltage generation circuit 10 detects the completion of charging of any capacitor cell and performs the operation of the bypass circuit 17 in order to perform preset constant current charging. Such constant current charging operation is performed.

  Next, when the constant current and constant power charging voltage generation circuit 10 detects the operation of all individual bypass circuits (bypass circuit 17a, etc.), the signal a ("H" signal) for stopping the charging operation is output to the OR circuit. 30 to the switching regulator IC 13.

  In this example, a D / A converter is used to output an analog voltage. However, a PWM signal may be output from a normal output port and smoothed by a resistor R5 and a capacitor C4 to obtain an analog voltage. .

  In addition, the DC output rectified by the rectifier circuit 4 and smoothed by the choke coil 5 and the capacitor C2 is supplied to the constant voltage power supply circuit 8, and the low voltage stabilized by the constant voltage power supply circuit 8 generates constant current and constant power. It is supplied as a power source for the charging voltage generation circuit 10.

  The output terminals T1, T2, and T3 are terminals for taking out the stored power of the capacitor cell to the outside.

FIG. 4 shows a main part of another configuration example of the circuit of FIG. That is, this example uses the circuit of FIG. 4 in place of a part of the circuit composed of the charging voltage detection circuit 31 and the like in the circuit of FIG. The circuit elements in FIG. 4 are the same as those in FIG.
Signals a, c, d in the circuit of FIG. 4 are shown in FIG. 4 differs from FIG. 3 in that the signal a, that is, the terminal voltage of the entire capacitor bank 9 is applied to the inverting input terminal of the comparator 42 instead of the terminal voltage of the single capacitor cell 9r.

  That is, FIG. 4 shows a case where the charging voltage of the entire capacitor bank 9 is detected, and when the charging voltage falls below a preset threshold, the relay 11 is closed and the charging voltage is higher than the preset threshold. Is a circuit that opens the contact of the relay 11.

  Although a circuit system is not shown, the heaters 29 and 30 are also heated by receiving power from the commercial AC power supply AC.

  As is apparent from the above description, the image forming apparatus 1 uses the capacitor bank 9 in which a plurality of capacitor cells are connected in series as a power storage unit, and the constant current and constant power charging voltage generation circuit 10 as a charging device. To charge. The full-wave rectifier circuit 11, the smoothing capacitor C1, and the above-described circuit at the subsequent stage are used as the first power supply circuit, and the circuits such as the full-wave rectifier circuit 32, the smoothing capacitor C4, and the DC / DC converter 33 are used as the second power supply circuit. .

  The energy saving mode is realized by processing executed by the image forming apparatus control unit 12 (power supply means). Some circuits that maintain power supply even in the energy saving mode are the LAN control circuit 24 and a part of the image forming apparatus control unit 12. (Reference numeral 12 c), a memory 25.

  The reference voltage circuit 39 is the first voltage detection circuit, the charge voltage detection circuit 31 is the first comparison means, and the relay 11 and the circuit 37 are the first charge means.

  With such a configuration, in the energy saving mode, the image forming apparatus 1 turns off the above-described power supply circuit serving as the second power supply circuit, and from the capacitor bank 9 to the LAN control circuit 24 and a part of the image forming apparatus control unit 12 ( Reference numeral 12 c) supplies power to the memory 25.

  Therefore, the energy saving mode can be maintained without supplying power at a high output from the second power supply circuit, and power saving can be achieved compared to the conventional case.

  Even during the energy saving mode, when the capacitor bank 9 is charged due to spontaneous discharge or the energy saving mode is extended for a long time, the relay 11 can be closed and the capacitor bank 9 can be charged. Further power saving can be achieved by consuming only the minimum necessary power during the energy saving mode.

  Next, another configuration example of the power supply device provided in the image forming apparatus 1 will be described.

  FIG. 5 is a circuit diagram of the power supply device. In the following description, differences from the configuration and operation of the circuits in FIGS. 3 and 4 will be mainly described, and common points will be denoted by the same reference numerals as those in FIGS. 3 and 4 and detailed description thereof will be omitted.

  As shown in FIG. 5, the circuit example includes a power storage unit 46 connected in parallel to the capacitor bank 9 and a circuit for charging the power storage unit 46. That is, the open / close circuit 45, the storage means 46, the charging voltage detection circuit 47, and the control circuit 50.

  FIG. 6 shows a circuit example in which one electric double layer capacitor is used as the switching circuit 45 and the power storage means 46 shown in FIG.

  The switching circuit 45 in FIG. 6 is closed when the electric double layer capacitor C becomes equal to or lower than a preset charging voltage, and the electric double layer capacitor C is charged from the charging circuit in FIG. 5 and exceeds the preset charging voltage. It is a circuit that opens and stops charging from the charging circuit. Charging is performed from commercial AC AC or capacitor bank 9.

  Further, the open / close circuit 45 stops the power supply to the charging circuit when the main power is turned off or in the energy saving mode, and the electric double layer capacitor C is set to a preset charging voltage or less. This is a circuit that closes and charges the electric double layer capacitor C from the capacitor bank 9.

  This will be described in detail below.

  A charge voltage detection circuit 47 is connected in parallel to the power storage means 46 which is an electric double layer capacitor C.

  The charging voltage detection circuit 47 includes a shunt regulator X1 and resistors R1 to R3. The control circuit 50 that controls the opening / closing of the switching circuit 45 based on the output of the charging voltage detection circuit 47 includes resistors R4, R5, R6 and a transistor Q2. The divided voltage of the voltage dividing circuit composed of the resistors R1 and R2 is input to the control terminal of the shunt regulator X1, and the charging voltage is detected.

  When the terminal voltage of the electric double layer capacitor C is charged to a predetermined voltage, the shunt regulator X1 is turned on. When the shunt regulator X1 is turned on, a base current flows through the resistor R4 to the transistor Q2, and the transistor Q2 is turned on. When the transistor Q2 is turned on, the base voltage of the transistor Q1 becomes “H” by the resistors R6 and R7, and the transistor Q1 is turned off.

  On the contrary, when the terminal voltage of the capacitor C becomes a predetermined voltage or less, the shunt regulator X1 is turned OFF. When the shunt regulator X1 is turned off, the transistor Q2 is turned off. When the transistor Q2 is turned off, a base current flows to the transistor Q1 through the resistors R6 and R7, the transistor Q1 is turned on and the electric double layer capacitor C is charged. The external output terminal T1 is connected to the terminal T1 in FIG.

  Next, FIG. 7 shows a circuit example in which two lithium ion secondary batteries are connected to the power storage means 46 in series.

  In FIG. 7, the operation of detecting the charging voltage of the lithium ion secondary battery BT by the charging voltage detection circuit 47 and controlling the switching circuit 45 is the same as in FIG. The charging circuit 48 for charging the lithium ion secondary battery has a constant voltage / constant current charging function. In FIG. 7, the description of the same configuration as in FIG. 6 is omitted.

  Returning to FIG. 5, in this example, when the power supply to the image forming apparatus control unit 12 and the LAN control circuit 26 is stopped by the energy saving mode, the output of the open collector circuit 34 is also opened, The power of the power storage means 46 is supplied and lights up.

  The power of the storage unit 46 is also supplied from the output terminal T1 and the output terminal T2 to the memory 25 of the image forming apparatus 1, the LAN control circuit 26, and some control circuits 12c of the image forming apparatus control unit 12.

  A LAN control circuit 26 is connected to the image forming apparatus control unit 12 and is supplied with power by the power storage means 46 in the energy saving mode.

  The voltage at the output terminal T1 of the power storage means 46 is set lower than Vcc, the main power supply is turned on, and Vcc power is supplied to the LAN interface circuit 26 and a part of the control circuit 12c of the image forming apparatus control unit 12. In this case, power is not supplied from the output terminal T1 of the power storage means 46 to the LAN interface circuit 26 and some control circuits 12c of the image forming apparatus control unit 12.

  When the main power supply of the image forming apparatus 1 is normally turned on, power is supplied to the memory 25 by the power supply circuit 24. In the energy saving mode or when the main power supply is OFF, the memory 25 is backed up by the output voltage of the output terminal T1. The memory 25 is an SRAM, SDRAM, DDR, or the like.

  When the inverting input terminal voltage of the comparator becomes lower than the voltage of the reference voltage circuit 39, the charging voltage detection circuit 31 having the hysteresis characteristic outputs a signal “H” for closing the relay 11 to the transistor Tr2. The transistor Tr2 is turned on, the transistor Tr3 is turned off, the relay 11 is in a non-energized state, the contact of the relay 11 is closed, and charging of the capacitor bank 9 and the electricity removing means 46 is started.

  FIG. 8 shows a main part of another configuration example of the circuit of FIG. That is, this example uses the circuit of FIG. 8 in place of a part of the circuit constituted by the charging voltage detection circuit 31 and the like in the circuit of FIG. The circuit of FIG. 8 has the same circuit elements as those of FIG. Signals c and d in the circuit of FIG. 8 are shown in FIG. The signal e is shown in FIGS. The circuit of FIG. 8 differs from that of FIG. 5 in that the signal e, that is, the terminal voltage of the storage means 46 is applied to the inverting input terminal of the comparator 42 instead of the terminal voltage of the entire capacitor bank 9.

  That is, FIG. 8 detects the charging voltage of the power storage means 46, and when the charging voltage is lower than a preset threshold value, the contact of the relay 11 is closed and the charging voltage is higher than the preset threshold value. This is a circuit for opening the contact of the relay 11.

  As described above, in the circuit shown in FIG. 5 and subsequent figures, the capacitor bank 9 in which a plurality of capacitor cells are connected in series and the power storage means 46 serving as a predetermined battery are connected in parallel, and the charging power of the power storage means 46 serving as a battery is obtained. Are supplied to the LAN control circuit 24, a part of the image forming apparatus control unit 12 (reference numeral 12c), and the memory 25.

  The reference voltage circuit 39 serving as the first voltage detection circuit detects the terminal voltage of the capacitor bank 9, and the relay 11 and the circuit 37 serving as the first charging unit charge the capacitor bank 9.

  On the other hand, the charging voltage detection circuit 47 serving as the second voltage detection circuit detects the terminal voltage of the power storage means 46, and when the voltage drops, the switching circuit 45 serving as the second comparison means and the second charging means uses the capacitor bank. The power storage means 46 is charged from 9.

  Therefore, the LAN control circuit 24 in the energy saving mode, a part of the image forming apparatus control unit 12 (reference numeral 12c), and a decrease in the voltage of the power storage means 46, which is an auxiliary power source dedicated to supplying power to the memory 25, are determined. Since charging is performed only when the voltage drops below a predetermined value, further power saving can be achieved as compared with the circuit of FIG.

  Next, another configuration example of the power supply device provided in the image forming apparatus 1 will be described.

  FIG. 9 is a circuit diagram of the power supply device. The following description will focus on differences from the configuration and operation of the circuit shown in FIG. 5 and below, and the common points are denoted by the same reference numerals as those in FIG.

  In the above-described example, the commercial power AC is supplied to the image forming apparatus control unit 12 from before the relay 11, the DC / DC converter 33 is turned off in the energy saving mode, and the DC / DC converter 33 is released when the energy saving mode is released. Is ON.

  In contrast, in this example, all the power of the image forming apparatus 1 is supplied via the relay 11, and in the energy saving mode, the relay 11 is opened to stop the power supply to the image forming apparatus 1, and the energy saving mode. At the time of release, the relay 11 is closed to supply power to the image forming apparatus 1.

  When the image forming operation is not performed for a certain time after the image forming apparatus 1 performs the image forming operation, the CPU 12a enters the energy saving mode in which the power of the image forming apparatus 1 is reduced. When entering the energy saving mode, the CPU 12 a outputs a signal “H” for opening the relay 11 from the port 1 to the open collector circuit 34. By the output of the open collector circuit 34, the transistor Tr3 of the relay drive circuit 37 is turned on, and the relay 11 is turned on. When the relay 11 is energized, the relay 11 is opened. When the relay 11 is opened, the supply of the commercial AC power supply AC to the image forming apparatus 1 is stopped.

  When canceling the energy saving mode, the energy saving mode cancel SW 36 is turned ON. When the energy saving mode release SW 36 is turned on, the transistor Tr4 is turned on and the transistor Tr3 of the relay drive circuit 37 is turned off, so that the relay 11 is in a non-energized state and the normally closed relay 11 is in a closed state. Thus, the commercial AC power supply AC is supplied to the image forming apparatus 1, and the energy saving mode is canceled. The image forming apparatus 1 performs the same operation as when the main power SW 35 is turned on.

  A LAN control circuit 26 is connected to the image forming apparatus control unit 12, and in the energy saving mode, power is supplied from the capacitor 9q.

  When receiving the LAN signal in the energy saving mode, the LAN control circuit 26 outputs the energy saving mode release signal “Low” to the transistor Tr3. Since the transistor Tr3 of the relay drive circuit 37 is in an OFF state, the relay 11 is in a non-energized state, the normally closed relay 11 is in a closed state, AC power is supplied to the image forming apparatus, and the energy saving mode is Canceled.

  The example in which the electronic apparatus of the present invention is applied to the image forming apparatus has been described above, but the electronic apparatus of the present invention is not limited to the image forming apparatus, and can be applied to various electronic apparatuses.

1 is an explanatory diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is an explanatory diagram illustrating a configuration of a fixing device. 2 is a circuit diagram of a power supply device provided in the image forming apparatus. FIG. It is a circuit diagram of the other example of a power supply device. It is a circuit diagram of the other example of a power supply device. It is a circuit diagram which shows detailed circuit structures, such as a switching circuit. It is a circuit diagram which shows detailed circuit structures, such as a switching circuit. It is a circuit diagram of the other example of a power supply device. It is a circuit diagram of the other example of a power supply device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus, electronic device 2 1st power supply circuit 9 Capacitor bank, electrical storage part 10 Charging apparatus 11 1st charging means 12c Some circuits 21 Fixing roller 22 2nd heater, load 24 Some circuits 25 Some circuits , Memories 20, 30 first heater 31 first comparison means 32 second power supply circuit 33 second power supply circuit 37 first charging means 39 first voltage detection circuit 45 second comparison means, second charging means 46 capacitor, power storage unit 47 Second voltage detection circuit 111 Fixing device C1 First power supply circuit C4 Second power supply circuit

Claims (20)

A power storage unit for storing power;
A predetermined load that receives power from the power storage unit;
A charging device for charging the power storage unit;
A first power supply circuit for supplying power to the charging device using a commercial power supply as a power supply;
A second power supply circuit for supplying power to some circuits of the apparatus other than the load using the commercial power supply as a power supply;
Power supply means for stopping power supply by the first power supply circuit and the second power supply circuit in the energy saving mode of the apparatus and supplying charging power of the power storage unit to the partial circuit;
A first voltage detection circuit for detecting a charging voltage of the power storage unit;
First comparison means for comparing the detected voltage with a preset reference value;
A first charging means for charging the charging unit by the charging device when the detected voltage falls below the reference value in this comparison;
Equipped with electronic equipment.   The electronic device according to claim 1, wherein the first charging unit performs charging by the charging device by closing a switch that opens and closes a line between the commercial power source and the charging device.   The electronic device according to claim 2, wherein the switch is a relay that closes when power is not supplied.   4. The electronic device according to claim 1, wherein the part of the circuit includes a circuit that detects an input of a signal from the outside of the apparatus and returns the apparatus from the energy saving mode. 5. machine.   The electronic device according to claim 1, wherein the partial circuit includes a predetermined memory of the apparatus.   The electronic device according to claim 1, wherein the power storage unit is a capacitor bank in which a plurality of capacitor cells are connected in series.   The electronic device according to claim 6, wherein the first voltage detection circuit detects a voltage across the capacitor bank.   The electronic device according to claim 6, wherein the first voltage detection circuit detects a voltage of at least one capacitor cell constituting the capacitor bank. The power storage unit is formed by connecting a capacitor bank in which a plurality of capacitor cells are connected in series and a predetermined power storage unit in parallel.
The power supply means supplies charging power of the battery in the power storage unit to the partial circuit.
The electronic device as described in any one of Claims 1-5.   The electronic device according to claim 9, wherein the first voltage detection circuit detects a charging voltage of the battery.   The electronic device according to claim 9, wherein the first voltage detection circuit detects a charging voltage of the capacitor bank. The first voltage detection circuit detects a terminal voltage of the capacitor bank;
The first charging means charges the capacitor bank when the detected voltage falls below the reference value in the comparison,
A second voltage detection circuit for detecting a charging voltage of the capacitor;
Second comparison means for comparing the detected voltage with a preset reference value;
A second charging means for charging the capacitor by the capacitor bank when the detected voltage falls below the reference value in this comparison;
The electronic device according to any one of claims 9 to 11, further comprising: A power storage unit for storing power;
A predetermined load that receives power from the power storage unit;
A charging device for charging the power storage unit;
A first power supply circuit for supplying power to the charging device using a commercial power supply as a power supply;
A second power supply circuit for supplying power to some circuits of the apparatus other than the load using the commercial power supply as a power supply;
Power supply means for stopping power supply by the first power supply circuit and the second power supply circuit in the energy saving mode of the apparatus and supplying charging power of the power storage unit to the partial circuit;
With
The power storage unit is formed by connecting a capacitor bank in which a plurality of capacitor cells are connected in series and a predetermined power storage unit in parallel.
The power supply means supplies charging power of the battery in the power storage unit to the partial circuit.
Electronics.   The electronic device according to claim 9, wherein the capacitor is an electric double layer capacitor.   The electronic device according to claim 9, wherein the battery is a lithium ion battery. A fixing device;
A power storage unit for storing power;
A first heater for heating a fixing roller of the fixing device using a commercial power source as a power source;
A second heater that receives supply of electric power from the power storage unit and heats the fixing roller of the fixing device;
A charging device for charging the power storage unit;
A first power supply circuit for supplying power to the charging device using the commercial power supply as a power supply;
A second power supply circuit for supplying power to some circuits of the apparatus other than the first and second heaters using the commercial power supply as a power supply;
Power supply means for stopping power supply by the first power supply circuit and the second power supply circuit in the energy saving mode of the apparatus and supplying charging power of the power storage unit to the partial circuit;
A first voltage detection circuit for detecting a charging voltage of the power storage unit;
First comparison means for comparing the detected voltage with a preset reference value;
A first charging means for charging the charging unit by the charging device when the detected voltage falls below the reference value in this comparison;
An electrophotographic image forming apparatus.   The image forming apparatus according to claim 16, wherein the power storage unit is a capacitor bank in which a plurality of capacitor cells are connected in series. The power storage unit is formed by connecting a capacitor bank in which a plurality of capacitor cells are connected in series and a predetermined power storage unit in parallel.
The power supply means supplies charging power of the battery in the power storage unit to the partial circuit.
The image forming apparatus according to claim 16 or 17. The first voltage detection circuit detects a terminal voltage of the capacitor bank;
The first charging means charges the capacitor bank when the detected voltage falls below the reference value in the comparison,
A second voltage detection circuit for detecting a charging voltage of the capacitor;
Second comparison means for comparing the detected voltage with a preset reference value;
A second charging means for charging the capacitor by the capacitor bank when the detected voltage falls below the reference value in this comparison;
The image forming apparatus according to claim 16, further comprising: A fixing device;
A power storage unit for storing power;
A first heater for heating a fixing roller of the fixing device using a commercial power source as a power source;
A second heater that receives supply of electric power from the power storage unit and heats the fixing roller of the fixing device;
A charging device for charging the power storage unit;
A first power supply circuit for supplying power to the charging device using a commercial power supply as a power supply;
A second power supply circuit for supplying power to some circuits of the apparatus other than the first and second heaters using the commercial power supply as a power supply;
Power supply means for stopping power supply by the first power supply circuit and the second power supply circuit in the energy saving mode of the apparatus and supplying charging power of the power storage unit to the partial circuit;
With
The power storage unit is formed by connecting a capacitor bank in which a plurality of capacitor cells are connected in series and a predetermined power storage unit in parallel.
The power supply means supplies charging power of the battery in the power storage unit to the partial circuit.
An electrophotographic image forming apparatus.

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