JP2008278680A - Power supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the load voltage fluctuation caused by switching power supply to a load from a main power supply (first power supply) or from an auxiliary power supply (second power supply). <P>SOLUTION: The power supply device used for a peripheral device 103 which performs operation in synchronism with the operation of a copier body 101 includes: the first power supply 30 provided at the copier body 101; a capacitor 37 which is provided at the peripheral device 103 and in which power supplied from the first power supply 30 is used for an input source; and a second power supply 26 which is provided at the peripheral device 103 and in which power of the capacitor 37 is used for the input source. The output of the first power supply 30 supplied from the copier body 101 and the output of the second power supply 26 are connected in parallel with each other, both power from the first power supply 30 and the second power supply 26 are simultaneously supplied to the loads, and power from the main device is restricted to be not more than the upper limit value. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply device used for a peripheral device that operates in synchronization with the operation of an image forming apparatus such as a main device, such as a printer, a copying machine, a facsimile machine, or a digital multifunction peripheral, and is supplied with power from the main device. In particular, the present invention relates to a power supply device provided with an auxiliary power supply including a power storage device and a power supply circuit using the power as an input source in addition to a power supply using power supplied from a main device.

  In recent years, environmental problems have become important and image forming apparatuses such as copiers and printers have been saving energy. In considering the energy saving of this image forming apparatus, what cannot be ignored is the electric power used in the fixing device for fixing the toner to the recording medium. That is, conventionally, when energy saving is considered in the image forming apparatus, the temperature of the heating roller is maintained at a constant temperature slightly lower than the fixing temperature during standby when the fixing operation is not performed by the fixing device, and the heating roller The heating state is immediately raised from the temperature to the usable temperature so that the user does not wait for the temperature of the fixing roller to rise.

  In this case, since the constant temperature is maintained even during standby when the fixing device is not used, a certain amount of electric power necessary for the maintenance is supplied. Therefore, extra energy is consumed relative to the energy actually required for fixing. In fact, it is said that the energy consumption during standby is approximately 70% to 80% of the energy consumption of the device. It is desired to reduce power consumption during standby and to further reduce power consumption, and there is a demand for zero power supply when not in use.

  However, if energy consumption is reduced to zero during standby, the heating roller mainly uses a metal roller such as iron or aluminum and has a large heat capacity, so it takes several minutes to raise the temperature to a usable temperature of about 180 ° C. A long heating time such as ten or more minutes is required, and the convenience for the user is deteriorated. For this reason, a configuration for quickly increasing the temperature of the heating roller is required for realizing an energy-saving copying machine.

  The heating time of the heating roller can be shortened by increasing the input energy per unit time, that is, the rated power. In fact, many high-speed machines with high printing speeds are compatible with a power supply voltage of 200V. However, in a general office in Japan, the commercial power supply is 100V15A, and in order to make it compatible with 200V, it is necessary to carry out a special work related to the power supply at the installation location, so it cannot be said that it is a general solution. In addition, a product that increases the total input power by using two systems of 100V15A has been put into practical use, but cannot be installed unless the outlets of the two systems are nearby. For this reason, even if an attempt is made to raise the temperature of the heating roller in a short time, the actual upper limit of the input energy cannot be increased.

  On the other hand, the functions of image forming apparatuses have also been diversified, and an automatic document feeder that automatically conveys a document to a document reading position and automatically discharges the document after reading is automatically performed for the loaded document. Alternatively, there is a sorting peripheral device that processes sheets discharged from the image forming apparatus main body, such as sorting, punching, and stapling. These peripheral devices have diversified functions, and actual operating power has increased.

  Therefore, for example, a system including an auxiliary power supply with respect to a main power supply as described in Patent Document 1 is known. In this system, power that is insufficient when supplying power using a main power supply is supplemented by an auxiliary power supply.

  That is, the present invention can cope with sudden output fluctuations without increasing the capacity of the auxiliary power supply more than necessary, and equalizes the power used so as not to exceed the maximum suppliable power of the AC line. The first power supply means that cannot store power, the second power supply means that can store power, and the power supply to some loads from the first power supply means Switching means for switching whether to perform or from the second power supply means, and switching control means for controlling the switching means, the control means predicts the power consumption, and the predicted power consumption is the first power When the power that can be supplied by the supply means is exceeded, the switching means is controlled so that power is supplied to some of the loads from the second power supply means.

  Patent Document 2 provides an image forming apparatus and a control method therefor that can more effectively utilize the upper limit current (electric power) of a commercial power supply and realize on-demand fixing with a faster temperature rise than ever. , Having a chargeable / dischargeable capacitor, and a load other than the heating element of the fixing unit can be supplied with power from either a commercial power source and / or a capacitor, and a temperature detection element provided in the fixing unit during printing Thus, the temperature of the fixing device is detected, and the power supply from the commercial power source and the storage device to the load is controlled according to the detected temperature, and the power supplied from the commercial power source to the fixing device is set to a limit level according to the control result. A limited invention is disclosed.

Specifically, in Patent Document 1, the power of the main power source and the auxiliary power source that uses the power that is constantly supplied from the outside is selectively switched and supplied by a switching circuit to a part of the load of the image forming apparatus. A power supply device and an image forming apparatus are described. In Patent Document 2, a constant voltage power supply circuit is used as an auxiliary power supply and its output voltage is set higher than the output voltage of the main power supply. A diode that prevents backflow to the main power supply is provided in the power supply line from the main power supply to the load. The auxiliary power supply output voltage is applied to the power supply line between the diode and the load via a switch or another diode, and the output voltage of the auxiliary power supply is higher than the output voltage of the main power supply. When the voltage is high, the load is supplied only from the auxiliary power supply. When the output voltage of the auxiliary power supply is lower than the output voltage of the main power supply, the load is supplied only from the main power supply. Describes an image forming apparatus that performs switching power feeding only from the above.
JP 2004-236492 A JP-A-2005-221474.

  The power that can be used in the image forming apparatus is limited for installation reasons. On the other hand, when the user turns on the power switch SW, it is desirable to perform the initialization operation and warm-up of the heat fixing unit in a short time in order to make it usable in a short time. When a peripheral device is mounted, the initialization operation is particularly large, and if they are performed simultaneously, the power consumption exceeds the usable value. When many peripheral devices are attached, the power consumption becomes higher.

  Therefore, a power supply device having a power storage device is provided in a peripheral device that consumes a large amount of current during initial operation, and the current generated from the stored power and the current supplied from the main body are supplied to the load at the same time. The received current value is kept below the current value that can be supplied by the main unit.

  Further, in the invention described in Patent Document 1, the power output circuit of the power storage device, that is, the power feeding circuit to the load is configured by a constant voltage power source. Therefore, the AC / DC power source of the main device which is a constant voltage power source is provided by the switching circuit. (PSU) and the output of a peripheral power supply (DDC), which is also a constant voltage power supply, when switching power to the load, voltage fluctuations occur at the time of switching due to the difference between the output voltages of the two constant voltage power supplies. Will occur. When voltage fluctuation occurs, there is a problem that the operation of the motor supplying power becomes unstable and the motor stops or rotation unevenness occurs. Uneven rotation of the motor causes abnormal operation in the peripheral device. For example, when the peripheral device is a post-processing machine (finisher), the transfer paper is wrinkled or the punch hole position is displaced.

  In addition, when power is supplied from the auxiliary power supply to only a part of the load by the switching circuit, it is necessary to divide the load into a group that switches power supply as such and a group that supplies power only from the main power supply. This grouping is appropriate for the equipment unit or electrical circuit unit to which the load belongs, but it may not be optimal power distribution (load classification), and the storage capacitor in the auxiliary power supply is required. There arises a problem that the capacity becomes large, or the level of consumption of AC power that is external input power becomes insufficient.

  Therefore, the problem to be solved by the present invention is to prevent load voltage fluctuation due to switching between power feeding from the main power source (first power source) and power feeding from the auxiliary power source (second power source).

  In order to solve the above problems, a first means is a power supply device used in a peripheral device that operates in synchronization with the operation of the main device, and is provided in the first power source provided in the main device and the peripheral device. A power storage device using the power supplied from the first power source as an input source, and a second power source using the power of the power storage device as an input source, and an output of the first power source supplied from the main device; The output of the second power source is connected in parallel, and both the power from the first power source and the power from the second power source are simultaneously supplied to the load, and the power supplied from the main device is equal to or less than the upper limit value. A power supply device limited to

  According to a second means, in the first means, the power storage device includes a capacitor.

  A third means is characterized in that, in the second means, the capacitor is an electric double layer capacitor.

  According to a fourth means, in the second or third means, the power storage device further includes a capacitor charging means for charging the capacitor.

  According to a fifth means, in any one of the first to fourth means, the peripheral device includes means for changing the upper limit value of the power supplied from the main device according to an instruction from the main device. Features.

  A sixth means is characterized in that, in the fifth means, the main device instructs the changing means to an upper limit power that can be supplied to the peripheral device via a communication means.

  The seventh means is characterized in that, in the sixth means, the suppliable upper limit power instructed from the main device is set in accordance with other peripheral devices attached thereto.

  The eighth means is characterized in that, in the sixth means, the upper limit power that can be supplied instructed from the main apparatus is set according to an operating state of the main apparatus.

  According to a ninth means, in any one of the first to fourth means, charging of the power storage device is performed during a period in which the output of the second power supply is stopped, and the power is supplied from the main device during charging. The electric power is less than the upper limit value.

  A tenth means is the ninth means, characterized in that charging to the power storage device is started by an instruction from a main device.

  The eleventh means is characterized in that, in the ninth means, the charging of the power storage device is started when the power supplied from the main device becomes smaller than the upper limit value by a certain value or more.

  A twelfth means is the power supply from the second power source when the output voltage of the power storage device becomes a predetermined value or less during the power supply from the second power source in any one of the first to fourth means. It stops, and operation | movement is changed so that the electric power supplied from a main power supply device may become below an upper limit.

  A thirteenth means is characterized in that, in any one of the first to twelfth means, the main device is an image forming apparatus.

  In the embodiment described later, the main device is the copier body 101, the peripheral device is the paper post-processing peripheral device 103, the first power source is the constant voltage power source 30, the power storage device is the capacitor 37 or the capacitor charger 38, The communication means corresponds to the serial I / F 80, respectively. The additional current detector 33, the current indicator 64, and the input / output control unit 20 limit the power supplied from the main device below the upper limit value.

  According to the present invention, since the power supplied from the main device is limited to the upper limit value or less, the load voltage is generated by switching between power feeding from the main power source (first power source) and power feeding from the auxiliary power source (second power source). Variations can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. In FIG. 1, an image forming apparatus includes an image forming apparatus main body 101, an automatic document feeding peripheral device 102 provided on the upper portion of the image forming apparatus main body 101, and a sheet post-processing peripheral provided on a discharge side surface of the image forming apparatus main body 101. The apparatus 103 and a capacity feeding peripheral device 104 provided on the feeding side surface of the image forming apparatus main body 101 are configured. The automatic document feeding peripheral device 102 automatically conveys the document to the document reading position, and automatically performs an operation of discharging the document after reading only for the stacked documents. The sheet post-processing peripheral device 103 sorts sheets discharged from the image forming apparatus main body 101 such as sorting, punching, stapling, and sheet folding. The large-capacity paper feeding peripheral device 104 stacks a large amount of paper for paper feeding and feeds the paper to the image forming apparatus main body 101 side. In general, among these peripheral devices, a paper post-processing peripheral device (sorting peripheral device) 103 for realizing multifunctional operations such as sorting, punching, stapling, and paper folding has the largest number of actuators and sensors. The power consumption during initialization operations such as forming operation and power-on is the highest. Note that the recording medium on which image formation is performed by the image forming apparatus is a sheet-like recording medium, and hereinafter referred to as a sheet, includes recording paper, paper, OHP, film, and the like.

  FIG. 2 is a diagram showing an outline of a system configuration of a system including the image forming apparatus main body 101 and the peripheral device 106 shown in FIG. The image forming apparatus main body 101 is composed of a digital copying machine in FIG. This digital copying machine is for monochrome image formation. The main body 400, the image reading device 500 installed on the upper side of the digital copying machine main body 400, and the automatic original as the automatic original feeding peripheral device 102 mounted thereon. A feeding device (hereinafter referred to as “ADF”) 550, a large-capacity paper feeding device 700 as a large-capacity paper feeding peripheral device 104 disposed on the right side of the digital copying machine main body 400 in FIG. A sheet post-processing device 800 serving as a sheet post-processing peripheral device 103 disposed on the left side of FIG.

  The digital copying machine main body 400 includes an image writing unit 410, an image forming unit 420, a fixing unit 430, a duplex conveying unit 440, a paper feeding unit 450, a vertical conveying unit 460, and a manual feeding unit 470.

  The image writing unit 410 modulates the LD, which is a light source, based on the image information of the document read by the image reading device 500, and writes laser on the photosensitive drum 421 by a scanning optical system such as a polygon mirror and an fθ lens. Corresponds to the optical writing device. The image forming unit 420 includes a photosensitive drum 421 and known electrophotographic imaging elements such as a developing unit 422, a transfer unit 423, a cleaning unit 424, and a charge eliminating unit provided along the outer periphery of the photosensitive drum 421. Consists of.

  The fixing unit 430 fixes the image transferred by the transfer unit 423 on the transfer paper. The double-sided conveyance unit 440 is provided downstream of the fixing unit 420 in the transfer sheet conveyance direction, and includes a first switching claw 441 that switches the transfer sheet conveyance direction to the sheet post-processing device 800 side or the double-side conveyance unit 440 side, , The reverse conveying path 442 guided by the switching claw 441, the image forming side conveying path 443 that conveys the transfer paper reversed by the reverse conveying path 442 to the transfer unit 423 again, and the reverse transfer paper after the sheet post-processing device 800. A second switching claw 445 is disposed at a branch portion between the image forming side conveying path 443 and the post processing side conveying path 444.

  The sheet feeding unit 450 includes four sheet feeding stages, and the transfer sheets stored in the sheet feeding stages selected by the pickup roller and the sheet feeding roller are drawn out and guided to the vertical conveyance unit 460. The vertical conveyance unit 460 conveys the transfer paper fed from each paper feed stage to the registration roller 461 immediately upstream in the paper conveyance direction of the transfer unit 423, and the registration roller 461 provides a visible image on the photosensitive drum 421. The transfer paper is fed into the transfer unit 423 in time with the leading edge. The manual feed portion 470 includes an openable and closable manual feed tray 471, and opens the manual feed tray 471 as needed to supply transfer paper manually. Also in this case, the transfer timing of the transfer paper is taken by the registration roller 461 and is transported.

  The large-capacity paper feeding device 700 supplies a large amount of transfer paper of the same size, and the bottom plate 702 rises as the transfer paper is consumed, so that the paper can always be picked up from the pickup roller 701. ing. Paper is fed from the pickup roller 701. The transfer paper is conveyed from the vertical conveyance unit 460 to the nip of the registration roller 461.

  The sheet post-processing apparatus 800 performs predetermined processing such as punching, alignment, stapling, and sorting. In this embodiment, the punch 801, the staple tray (alignment) 802, the stapler 803, and the shift tray 804 are used for the above functions. I have. In other words, the transfer paper carried from the image forming apparatus 400 to the paper post-processing apparatus 800 is punched one by one with the punch 801 when punching, and then if there is no particular processing, the proofing is performed. When sorting, stacking, and sorting to the tray 805, the sheets are discharged to the shift tray 804, respectively. In this embodiment, the sorting is performed by the reciprocating movement of the shift tray 804 by a predetermined amount in a direction orthogonal to the sheet conveyance direction. In addition, sorting can be performed by moving the paper in a direction orthogonal to the paper transport direction on the paper transport path.

  In the case of alignment, the transfer paper that has been punched or not punched is guided to the lower transport path 806, and the staple tray 802 is aligned in the direction perpendicular to the paper transport direction by the trailing edge fence. In the jogger fence, alignment in the direction parallel to the paper transport direction is performed. Here, when binding is performed, a predetermined position of the aligned sheet bundle, for example, a predetermined position such as a corner portion or two central positions is bound by the stapler 803 and discharged to the shift tray 804 by the discharge belt. In this embodiment, a pre-stack conveyance path 807 is provided in the lower conveyance path 806, and a plurality of sheets are stacked at the time of conveyance to avoid interruption of the image forming operation on the digital copying machine main body 400 side during post-processing. Be able to.

  The image reading apparatus 500 is guided onto the contact glass 510 by the ADF 600, optically scans the stopped original, and reads the image formed by the imaging lens through the first to third mirrors, such as a CCD or CMOS. Read by the photoelectric conversion element. The read image data is subjected to predetermined image processing by an image processing circuit (not shown) and temporarily stored in a storage device. Then, it is read from the storage device by the image writing unit 410 during image formation, modulated according to the image data, and optical writing is performed.

  The ADF 550 has a double-sided reading function, and is attached to the contact glass 510 installation surface of the image reading device 500 so as to be freely opened and closed. In the ADF 550, the document placed on the document placement table 551 is automatically sent onto the contact glass 510 when the document is read.

FIG. 3 is a block diagram illustrating the configuration of the power supply apparatus of the main body 101 and the sheet post-processing apparatus 103.
In the figure, a main body 101 is basically composed of a main power supply 29, a main power supply SW (switch) 29, a fixing heater 36, a 5V system load 70, a 24V system load 71 and an input / output control unit 72. Further, a constant voltage power source 30 (first power source) and a fixing power source 31 (second power source) are provided. In the main body 101 configured as described above, the commercial AC power supply 27 is supplied to the main power supply 29 when the main power supply SW28 is turned on (closed). As a result, the commercial AC voltage is applied from the commercial AC power source 27 to the fixing power source 31 and the constant voltage power source 30 which are AC control circuits of the main power source 29. The fixing power source 31 sets the fixing device temperature due to heat generated by the fixing heater 36 of the fixing device 430 (FIG. 2) within the phase angle limit corresponding to the fixing power instruction signal given from the input / output control 72 as a target value (reload target value / standby). The power supply thyristor is triggered to conduct at a thyristor conduction phase angle to match the (time target value / image formation target value), and AC power is supplied to the fixing heater 36.

  The constant voltage power supply 30 as the first power supply of the main power supply 29 converts commercial AC into DC, generates two DC constant voltages of 5V and 24V by constant voltage feedback control of the DC / DC converter, and generates a 5V system. Output to load 70 and 24V system load 71. The CPU of each control unit of the 5V load system operates using the 5V constant voltage generated by the constant voltage power supply 30. The 24V output of the main power supply 29 is supplied to the 24V system load 71, the paper post-processing peripheral device 103, and other peripheral devices not shown in FIG.

  The sheet post-processing peripheral device 103 includes a constant voltage power supply 81, an auxiliary power supply 32, a load current detector 33, a current indicator 64, a 5V load system 34, a 24V load system 35, and an input / output control unit 20. The auxiliary power supply 32 further includes a constant current power supply 26, a capacitor 37, a capacitor charger 38, a voltage detector 39, and an analog / digital converter 25.

  That is, in this embodiment, the auxiliary power source 32 is a constant current power source that outputs a constant current to a capacitor charger 38, a capacitor 37 charged by the capacitor charger 38, and a power supply line to the 24V system load 35. 26 (second power supply). The load current detector 33 detects a 24V system load current value that is the sum of the current values simultaneously supplied from the constant voltage power supply 30 (first power supply) and the constant current power supply 26 (second power supply) supplied from the main body 101. Then, a current detection signal is given to the current indicator 64.

  To the current indicator 64, the input / output control unit 20 gives the upper limit instruction data MCD that designates the 24V power supply current upper limit value that can be supplied by the main unit 101 received from the input / output control unit 72 of the main unit 101 through the serial IF 80. The current indicator 64 supplies the constant current power supply 26 with a current instruction signal indicating a value obtained by subtracting the upper limit instruction value from the 24V system load current value, that is, an output current instruction value of the constant current power supply 26. The constant current power supply 26 supplies the electric power of the capacitor 37 to the 24V system load line with constant current by constant current control using the current value indicated by the current instruction signal as a target value.

  When the main power SW 28 is switched from off to on, commercial alternating current is supplied to the fixing power source 31 and the constant voltage power source 30, the fixing power source 31 supplies power to the fixing heater 36, and the constant voltage power source 30 supplies 5V and 24V constant voltage. appear. At this time, if the fixing device temperature is low, the input / output control unit 20 increases the power consumption allocation to the fixing power source 31 and heats up (reloads) the fixing device 430. In this state, power consumption by the fixing heater 36 is large. The standby mode is a state in which the fixing device 430 finishes heating up and waits for a print instruction. In this state, the power consumption of the copying machine is small. When there is a standby mode copy or print instruction, a printer controller (not shown) instructs the input / output control unit 72 of the main body 101 to copy or print, and the input / output control unit 72 starts a copy or print operation. The state in which the input / output control unit 72 is executing copying or printing is an operation mode, and power consumption is large. The input / output control unit 20 of the paper post-processing peripheral device 103 controls the sensors and various loads in accordance with the control command of the input / output control unit 72 of the main body 101.

  In the present embodiment, the capacitor 37 of the auxiliary power supply 32 is configured by a large-capacity capacitor such as an electric double layer capacitor. Various capacitors can be selected as the capacitor 37 other than the electric double layer capacitor, but this type of capacitor was adopted because the electric double layer capacitor can be charged and discharged in a short time and has a long life. A characteristic of the electric double layer capacitor is that the terminal voltage (capacitor voltage) becomes lower as it is discharged. Therefore, by arranging the constant current power source 26 after the capacitor 37, the required current value is obtained regardless of the fluctuation of the capacitor voltage. Is output.

  The capacitor charger 38 of the auxiliary power source 32 is connected to a 24V power source from the main power source 29 of the main body 101. Charging of the capacitor 37 is started and stopped by a charge ON / OFF instruction signal from the input / output control 20. Charging starts when the voltage of the capacitor 37 becomes a certain level or less and the power stored in the capacitor 37 is not supplied to the 24V system load 35 through the constant current power supply 26. This is because the period in which power is not supplied from the constant current power supply 26 is a period in which the 24 V power supply current supplied from the main body 101 is less than or equal to the upper limit value and there is room to consume current for charging.

  Charging starts when the input / output control unit 72 of the main body 101 sends an instruction to the input / output control unit 20 of the paper post-processing peripheral device 103 when the power consumption of the main body and other peripheral devices is low as in the standby mode.

  Further, when the discharge of the electric power stored in the capacitor 37 progresses and the voltage becomes a certain value or less, the electric power can no longer be supplied to the 24V system load 35. When the input / output control unit 20 detects this, the operation is changed, the current consumption of the 24V system load is reduced, and the current supply from the constant current power supply 26 is stopped. If it is during the initialization operation period, the initialization operation is interrupted. If the copy operation is being performed, the printer waits without stacking the sheets in a stacked state. Then, it notifies the input / output control unit 72 of the main body 101 that the voltage has become a certain value or less.

  The input / output control 72 of the main body 101 that has received the notification waits until the heat-up of the fixing device 430 of the main body is completed and the power consumption of the entire apparatus is reduced, and then the paper post-processing peripheral device 103. An instruction is sent to the input / output device 20 to resume the interrupted initialization operation. When waiting for the stapling operation, printing is temporarily interrupted, the power consumption of the entire apparatus is reduced, and then an instruction is sent to the input / output device 20 of the paper post-processing peripheral device 103 to perform the stapling operation.

  As another example of the start of charging, the input / output control unit 20 detects that the detected current of the load current detector 33 is equal to or less than a certain value, and thereby the 24V power supply current supplied from the main body 101 is higher than the upper limit value. It may be determined that the input current of the charger 38 is less than the input current, and charging may be started without an instruction from the input / output control unit 72 of the main body 101.

  FIG. 4 is a block diagram showing details of the constant current power supply 26, the load current detector 33, and the current indicator 64 provided in the paper post-processing peripheral device 103 shown in FIG. The capacitor 37 is an electric double layer capacitor as described above. The electric double layer capacitor has a low withstand voltage, and the charging upper limit voltage in use is 2.5V. Therefore, in order to obtain a high voltage, it is necessary to connect many in series. However, the same capacity can be obtained at a lower cost by using a small number of large-capacitance capacitors rather than connecting many small-capacitance capacitors in series. When electric double layer capacitors are used in a series number of 9 or less, in order to supply power to a 24V load, the charging upper limit voltage is 22.5V or less. Therefore, it is necessary to configure the constant current power supply 26 using a boost regulator. is there. Therefore, in this embodiment, the booster regulator 40 boosts the power of the capacitor 37 and outputs a constant current.

  The semiconductor switch 41 of the boost regulator 40 is turned on (ON) during the H period of the output PWM pulse of the PWM controller 42, and is turned off (OFF; off) during the L period. When the switch 41 is turned on, a current flows from the capacitor 37 to the reactor 43 and the switch 41, the reactor 43 stores power, and when the switch 41 is turned off, the stored power of the reactor 43 becomes high and the capacitor 44 passes through the diode 44. 45 is charged with high voltage. By repeating ON / OFF of the PWM pulse cycle of the switch 41, the voltage of the capacitor 45 rises, passes through the current detection resistor 47, through the semiconductor switch 56 of the power supply ON / OFF controller 55, and further to the current of the load current detector 33. Power is supplied to the 24V system load 35 through the detection resistor 60.

  FIG. 5 is a characteristic diagram showing the current value and voltage value inside the paper post-processing peripheral device 103. 5A is a graph showing a load current detection signal level (vertical axis) generated corresponding to the load current value (horizontal axis) of the load current detector 33 shown in FIG. 4, and FIG. 5B is a current instruction. FIG. 5C is a graph showing a current output instruction signal level (vertical axis) to the auxiliary power source 32 generated by the counter 64 in response to the load current detection signal level (horizontal axis). FIG. 5D is a graph showing the relationship between the detection signal level (horizontal axis) and the constant current power supply 26 and the 24V supply current value from the copying machine main body 101. FIG. 5 (d) shows the constant current power supply 26 by the high voltage limiting function of the voltage limiter 51. It is a graph which shows the relationship between an output voltage (horizontal axis) and an output current value (vertical axis).

  The load current detector 33 amplifies the potential difference between both ends of the current detection resistor 60 with a differential amplifier 61, and generates a load current signal proportional to the load current value (voltage drop voltage of the resistor 60: see FIG. 5A). It is generated and output (applied) to the current indicator 64 through a low-pass filter composed of a resistor 62 and a capacitor 63. The low-pass filter has a time constant of about several tens of msec that absorbs and smoothes overcurrent (inrush current) for a period of about 10 msec when the motor is started.

The current indicator 64 analog-converts the current upper limit value instruction data MCD provided by the input / output control unit 20 into an upper limit instruction signal (voltage) by the D / A converter 65, and the differential amplifier 66
The load current detection value−the upper limit instruction value is calculated, and the differential voltage representing the calculation result is interrupted by the diode 67 and output to the constant current power supply 26 as a current instruction signal. That is, the current indicator 64 determines the upper limit value of the 24V power supply current (AC power to the MCD: 30) received from the main body 101 instructed by the input / output control unit 20 from the 24V system load current detection value (required load current value). The difference value (see FIG. 5B) obtained by subtracting the upper limit value of the consumption allocation is used as a target current value to be borne by the constant current power supply 26, and the current output for that amount is instructed to the constant current power supply 26.

  The constant current power supply 26 amplifies the potential difference between both ends of the current detection resistor 47 by a differential amplifier 48 and generates an output current signal (voltage drop voltage of the resistor 47) proportional to the output current value. The bias circuit 49 supplies the differential amplifier 50 with a positive bias output current signal obtained by raising the voltage level of the output current signal by a set value. The differential amplifier 50 provides the PWM controller 42 with a difference between the target current value provided by the current indicator 64, that is, an error voltage of constant current feedback control, as a duty instruction signal of the PWM pulse from the positive bias output current signal.

  The PWM controller 42 determines the duty of the PWM pulse for driving the semiconductor switch 41 on / off to the duty specified by the duty instruction signal. That is, when the output signal of the current indicator 64 (target current value to be borne by the constant current power supply 26) increases and the output voltage of the differential amplifier 50 decreases, the duty of the PWM pulse is increased. As a result, the output current value of the boost regulator 40 increases. As a result, the voltage drop of the current detection resistor 47 increases, and when the output current detection signal level rises and the output voltage of the differential amplifier 50 rises, the duty of the PWM pulse is lowered. As a result, the output current value of the boost regulator 40 decreases.

  By such feedback PWM control, the output current value of the boost regulator 40 is supplied from the main body 101 instructed by the input / output control 20 from the 24V load current detection value (required load current value) given by the current indicator 64. This is a value corresponding to the difference obtained by subtracting the upper limit value MCD of the 24V power supply current. FIG. 5C shows a 24V load current detection value (solid line), an upper limit value (indicated value) MCD of the 24V power supply current supplied from the main body 101, and a 24V power supply current value (dotted line) supplied from the main body 101. And the relationship between the three values of the output current value (one-dot chain line) of the constant current power supply 26.

  In addition to the load that the input / output control unit 20 controls on / off, the 24V system load 35 includes a 24V system load such as a cooling fan that is always driven in the standby mode and the operation mode. Even when the 24V system load that is the control target is turned off (non-energized), the load current flows through the power supply line (load current detector 33) to the 24V system load. Since the boost regulator 40 shown in FIG. 4 is a boost type boost type, even if the PWM controller 42 stops the switching operation (PWM pulse output) of the semiconductor switch 41, the output voltage of the regulator 40 is the input voltage. If it falls below, current will flow from input to output. That is, the capacitor 37 is discharged. When the main power switch 28 is turned off, the 24V output voltage of the constant voltage power supply 30 disappears, and any of the 24V system loads is on, the capacitor 37 is discharged to the load. In order to prevent this, in the present embodiment, the constant current power supply 26 is provided with a power supply ON / OFF controller 55.

  The power supply ON / OFF controller 55 monitors the voltage at the output terminal of the power supply 26 with the voltage detector 57, which is obtained by subtracting the drop voltage due to the load current from the 24V output voltage lower limit value of the constant voltage power supply 30. When the value becomes a little smaller than a set value (for example, 22.8 V), the monitoring output signal is switched from the high level H at normal time to the low level L indicating an output low voltage abnormality. Since the input / output control 20 provides the AND gate 58 with the power ON / OFF instruction signal (H: ON instruction / L: OFF instruction), the monitoring output signal of the voltage detector 57 is H indicating normality. The output of the AND gate 58 is H, the transistor 59 is ON, and the semiconductor switch 56 is ON.

  However, when the monitoring output signal of the voltage detector 57 switches to L indicating a low voltage abnormality, the transistor 59 is turned OFF, the semiconductor switch 56 is turned OFF, and the power supply 26 output to the load power supply line is cut off. That is, the capacitor 37 is prevented from being discharged. The output signal of the AND gate 58 (H: current output instruction / L: current output cutoff instruction) is also given to the PWM controller 42. In response to this signal, the PWM controller 42 is H (current output instruction). The aforementioned PWM pulse is applied to the semiconductor switch 41 to drive it ON / OFF. If it is L (current output cutoff instruction), L is applied to the semiconductor switch 41 to constrain the semiconductor switch 41 to OFF. By turning off the semiconductor switch 41, the capacitor 37 passing through the semiconductor switch 41 is also prevented from being discharged.

  When the voltage at the output terminal of the constant current power supply 26 exceeds a threshold value (set value) set using the constant voltage element 52, the voltage limiter 51 changes the output of the comparator 53 from L representing normal to H representing abnormal. Switch to. This H increases the PWM control signal to the PWM controller 42 through the diode 54 to a voltage level that designates a duty of 0 or less, and restrains the semiconductor switch 41 to be continuously OFF. If the voltage at the output terminal of the constant current power supply 26 becomes abnormally high, the output current value detected by the resistor 47 is thereby lowered. In response, the PWM controller 42 increases the output current value so that the output current value is increased. Since the duty is increased, the high abnormality of the output voltage is further amplified. The voltage limiter 51 prevents such abnormal operation.

  The set value for stopping the operation of the regulator 40 of the voltage limiter 51 needs to be higher than the maximum value of the normal output voltage of the constant voltage power supply 30. In the present embodiment, the normal range of the output voltage of the constant voltage power supply 30 is set to 24V + 5% or less and −4% or more, so it needs to be 25.2V or more. On the other hand, the upper limit of the output voltage to the load 35 is 24V + 10%, so it is necessary to be 26.4V or less. Therefore, in this embodiment, the set value (limit voltage) of the voltage limiter 51 is set to a value within the range of 25.2V or more and 26.4V or less.

  FIG. 6 is a timing chart showing the transition of each output current. (A) is an apparatus input AC power characteristic with respect to the AC power supply line 27, (b) is an AC power consumption characteristic of the fixing power source 31, (c) is a 24V power output characteristic received from the main body 101, and (d) is a characteristic. The current characteristics of the load 35, (e) is the upper limit value MCD of the 24V power supply current received from the main body 101, and 24V power supply current characteristics supplied from the main body 101, (f) is the output current characteristic of the constant current power supply 26. Each change over time is shown.

The outline of the transition of the output current of the constant current power supply 26 is as follows.
That is, in the fixing reload period in which the fixing temperature is raised to the target temperature immediately after the main power supply SW 28 is turned on, in order to satisfy the starting time required for the apparatus, a larger amount of electric power than usual is supplied to the fixing heater 36, and the fixing is performed. The heater 36 is raised as soon as possible to a temperature at which printing can be performed. Fixing reload means raising the fixing temperature to a temperature at which printing can be performed. At this time, the upper limit value MCD of the 24V power supply current supplied from the main body 101 becomes a small value (FIG. 6D), and the 24V power supply supplied from the main body 101 to the + 24V system load 35 of the paper post-processing peripheral device 103 and Power is supplied simultaneously from both constant current power supplies 26, the AC power consumption of the constant voltage power supply 30 of the main body 101 is reduced, the AC power allocation of the fixing power supply 31 is increased, the fixing heater current is increased, and the startup time Shorten.

Further, once the fixing heater 36 reaches a temperature at which printing can be performed, the fixing heater supply power for maintaining the temperature may be smaller than that at the time of activation. After the fixing reload is completed, the upper limit value MCD of the 24V power supply current supplied from the main body 101 that the input / output control 72 of the main body 101 instructs the input / output control unit 20 of the paper post-processing device 103 becomes a large value (FIG. 6 ( e))
The upper limit value MCD of the 24V power supply current supplied from the main body 101 that the input / output control 72 of the main body 101 instructs the input / output control 20 of the paper post-processing device 103 is small when the power consumption of the main body and other peripheral devices is large. When the power consumption of the main body and other peripheral devices is small, it becomes large. In addition, the capacitor charger 38 is instructed to start charging, and the power supplied from the power supply line 27 is adjusted to be equal to or lower than the suppliable power.

As described above, according to the present embodiment,
1) It is possible to prevent fluctuations in load voltage due to switching between power feeding from the main power source (first power source) and power feeding from the auxiliary power source (second power source).
2) It is possible to smoothly control the power sharing at the same time for the power supply from the main power supply and the power supply from the auxiliary power supply to the load.
3) Leveling of the input power consumption of the main device can be made smoother.
There are effects such as.

1 is a diagram illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a diagram illustrating an outline of a system configuration of a system including an image forming apparatus main body and peripheral devices illustrated in FIG. 1. FIG. 2 is a block diagram illustrating a configuration of a power supply device of the copying machine main body and the sheet post-processing apparatus of FIG. 1. It is an electric circuit diagram which shows the structure of the constant current power supply of FIG. 3, a load current detector, and a current indicator. It is a figure which shows the electric current value and voltage value inside a paper post-processing peripheral device. It is a timing chart which shows the state of the current value of each part supplied from 24V power supply.

Explanation of symbols

20 Input / output control unit 26 Constant current power supply (second power supply)
29 Main power supply 30 Constant voltage power supply (first power supply)
33 Load current detector 35 24V system load 37 Capacitor 38 Capacitor charger 64 Current indicator 80 Serial I / F
101 Copier body (main unit)
102 Automatic document feeder peripheral (ADF)
103 Paper post-processing peripheral equipment (finisher)
104 Large-capacity paper feed peripheral device (paper feed bank)

Claims (13)

In a power supply device used for a peripheral device that operates in synchronization with the operation of the main device,
A first power source provided in the main unit;
A power storage device that is provided in the peripheral device and uses the power supplied from the first power source as an input source; and a second power source that uses the power of the power storage device as an input source;
With
The output of the first power source and the output of the second power source supplied from the main device are connected in parallel, and both the power from the first power source and the power from the second power source are simultaneously supplied to the load. A power supply device that limits power supplied from the main device to an upper limit value or less. The power supply device according to claim 1, wherein
The power storage device includes a capacitor. The power supply device according to claim 2, wherein
The power supply device, wherein the capacitor is an electric double layer capacitor. The power supply device according to claim 2 or 3,
The power storage device further includes capacitor charging means for charging the capacitor. The power supply device according to any one of claims 1 to 4,
The power supply apparatus according to claim 1, wherein the peripheral device includes means for changing an upper limit value of power supplied from the main device according to an instruction from the main device. The power supply device according to claim 5,
The main apparatus instructs the changing means to an upper limit power that can be supplied to the peripheral apparatus via a communication means. The power supply device according to claim 6, wherein
An upper limit power that can be supplied instructed from the main device is set according to other peripheral devices that are mounted. The power supply device according to claim 6, wherein
An upper limit power that can be supplied instructed from the main device is set according to an operating state of the main device. The power supply device according to any one of claims 1 to 4,
The power storage device is charged while the output of the second power supply is stopped, and the power supplied from the main device during charging is equal to or lower than an upper limit value. The power supply device according to claim 9, wherein
Charging to the power storage device is started by an instruction from a main device. The power supply device according to claim 9, wherein
Charging the power storage device is started when the power supplied from the main device becomes smaller than the upper limit value by a certain value or more. The power supply device according to any one of claims 1 to 4,
When the output voltage of the power storage device falls below a certain value while supplying power from the second power source, the power supply from the second power source is stopped so that the power supplied from the main power source device falls below the upper limit value. A power supply device characterized by changing its operation. The power supply device according to any one of claims 1 to 12,
A power supply apparatus wherein the main apparatus is an image forming apparatus.

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