JP2009070209A - Unit and method for power supply control, and image forming unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a unit and a method for power supply control and an image forming unit, controlling power supply according to a battery characteristic when supplying power from the battery to a plurality of loads, and securely backing up a load having higher importance. <P>SOLUTION: Backup time is set to maintain a function in the order of priority being preset according to the degree of importance of each of plurality of loads. Based on battery characteristic information showing the relationship among a discharge capacity of the battery for supplying power to each load, a discharge current and a final voltage, each power supply stop voltage for securing the backup time for each load is determined. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a power supply control device, a power supply control method, and an image forming apparatus, and in particular, includes a power supply control device that controls power supply from a backup auxiliary power supply to a plurality of load units, a power supply control method, and the power supply control device. The present invention relates to an image forming apparatus.

  Some power supply circuits mounted on electronic devices and the like include a backup power supply (auxiliary power supply) in addition to the main power supply in case a power interruption occurs. Such a device is configured to be able to back up functions such as a volatile memory and an RTC (Real-Time Clock) that performs timekeeping during a power failure or when the main power is turned off. For example, Patent Document 1 stores an image memory (DRAM: Dynamic Random Access Memory) that stores transmission / reception image data from a single primary battery, clock and device management data, and registration data when the main power of the facsimile apparatus is turned off. A technique is disclosed in which power supply to an SRAM (Static RAM) is started and power supply to an image memory is stopped after a predetermined time has elapsed.

JP 2001-238004 A

  However, in the technique of Patent Document 1, since power supply is stopped at the backup time of the image memory in accordance with the capacity of the image memory which is one of the loads, there is a problem that power supply control considering the characteristics of the battery cannot be performed. is there. For example, when the current supplied from the battery to the load is large, the usable battery capacity is reduced due to the voltage drop inside the battery, so that it becomes lower than the operating voltage of the load connected to the battery within the set backup time. there is a possibility. In addition, since the usable battery capacity varies depending on the battery operating temperature, when the battery capacity is the smallest, there is a possibility that the operating voltage of the load connected to the battery will be within the set backup time. . In these cases, not only the data in the image memory is erased, but also the clock function with higher importance is stopped and the data in the SRAM is erased.

  The present invention has been made in view of the above, and when power is supplied from a battery to a plurality of loads, power supply control is performed according to the characteristics of the battery, and a more important load is reliably backed up. An object of the present invention is to provide a power supply control device, a power supply control method, and an image forming apparatus that can perform the above-described processing.

  In order to solve the above-described problems and achieve the object, the invention according to claim 1 is directed to a battery, a plurality of load units that operate by electric power supplied from the battery, and the battery to each load unit. A plurality of switch means for individually controlling on / off of power feeding, and a voltage applied to each load section are monitored, and when the voltage reaches a predetermined power feed stop voltage, the switch means is turned off from the on state. A plurality of voltage monitoring means for individually switching to a state; a first storage means for storing battery characteristic information indicating a relationship between a discharge capacity of the battery, a discharge current, and a final voltage; and importance of each load unit Backup time setting means for preferentially setting a backup time from a load unit with a higher priority based on the priority order determined in accordance with the degree, and based on the current consumption and backup time of each load unit. And calculating a cumulative power consumption required until the backup time of each load unit expires, and a final voltage specifying means for specifying a final voltage corresponding to the cumulative power consumption and current consumption of each load unit from the battery characteristic information, And a stop voltage setting means for setting the end voltage specified for each load section as the power supply stop voltage in each of the voltage monitoring means related to the load section.

  According to a second aspect of the present invention, in the first aspect of the invention, the backup time setting means preferentially sets the backup time from a load unit having a high priority within the range of the battery capacity of the battery. It is characterized by that.

  The invention according to claim 3 is the invention according to claim 2, wherein the battery is a secondary battery, and the cycle number counting means for counting the number of times of charging / discharging of the battery; Third storage means for storing cycle characteristic information indicating the battery capacity of the battery, and the backup time setting means is configured to calculate the number of charge / discharge cycles counted by the cycle number counting means based on the cycle characteristic information. The battery capacity of the battery is determined.

  The invention according to claim 4 is the invention according to claim 2, wherein the battery is a secondary battery, and a cycle number counting means for counting the number of times of charging / discharging of the battery; Third storage means for storing cycle characteristic information indicating the battery capacity of the battery, and the backup time setting means is configured to calculate the number of charge / discharge cycles counted by the cycle number counting means based on the cycle characteristic information. The battery capacity of the battery is determined.

  The invention according to claim 5 is the invention according to claim 3 or 4, wherein the backup time setting means adds the power consumption of all the load units based on the current consumption and the backup time of each load unit. The total power consumption is calculated, and when the difference value between the total power consumption and the determined battery capacity is a predetermined value or more, the backup time of each load unit is adjusted.

  Further, in the invention according to claim 6, in the invention according to claim 5, when the backup time setting means determines that the battery capacity exceeds the total power consumption, the difference between the battery capacity and the total power consumption is calculated. The corresponding time is added from a load unit having a high priority.

  In the invention according to claim 7, in the invention according to claim 5, when the backup time setting means determines that the total power consumption exceeds the battery capacity, the difference between the total power consumption and the battery capacity is calculated. The corresponding time is subtracted from the load section having a low priority.

  The invention according to claim 8 is the invention according to claim 1, wherein the cumulative power consumption calculating means calculates the cumulative power consumption from a load section having a short backup time.

  Further, the invention according to claim 9 is the invention according to claim 1, wherein the end voltage specifying means does not specify the end voltage of the load section having the longest backup time among the plurality of load sections. It is characterized by.

  The invention according to claim 10 is the invention according to claim 1, wherein the battery is a secondary battery, and a main power source that supplies power from a commercial power source to each of the battery and the load unit; It further comprises switching means for switching the power supply from the main power source to the battery according to the power supply state of the main power source.

  According to an eleventh aspect of the present invention, there is provided a switching process for individually controlling on / off of power feeding from the battery to the plurality of load units, and monitoring each of the voltages applied to the load units. Based on the voltage monitoring step of individually switching the switch means from the on state to the off state when the power supply stop voltage is reached, and the priority order determined according to the importance of each load unit, Based on the backup time setting process that preferentially sets the backup time from a high load section, and the consumption current and backup time of each load section, the cumulative power consumption required until the backup time of each load section expires is calculated. Based on battery characteristic information indicating the relationship between the cumulative power consumption calculation step, the discharge capacity of the battery, the discharge current, and the end voltage, the cumulative power consumption of each load unit and A final voltage specifying step for specifying a final voltage corresponding to the power consumption, and a final voltage setting step for setting the final voltage specified for each load unit as a power supply stop voltage in the voltage monitoring step. It is characterized by.

  According to a twelfth aspect of the present invention, there is provided an image forming apparatus that includes a main power source and an auxiliary power source composed of a secondary battery that can be charged / discharged by the power from the main power source. A plurality of load units for printing the print data operated by power supplied from an auxiliary power source, and power supply to each load unit from the main power source to the auxiliary power source according to the power supply state of the main power source Switching means for switching, a plurality of switch means for individually controlling on / off of power feeding from the auxiliary power source to each load unit, and a voltage applied to each load unit are monitored, and the voltage is supplied to a predetermined power source. A plurality of voltage monitoring means for individually switching the switch means from the on state to the off state when the stop voltage is reached, and the relationship between the discharge capacity of the auxiliary power source, the discharge current, and the end voltage are shown. Storage means for storing the battery characteristic information, and backup time setting means for preferentially setting the backup time from the load section having a higher priority based on the priority order determined according to the importance of each load section And the cumulative power consumption required until the backup time of each load unit expires based on the current consumption and backup time of each load unit, respectively, and the termination corresponding to the cumulative power consumption and current consumption of each load unit End voltage specifying means for specifying the voltage from the battery characteristic information, and end voltage setting means for setting the end voltage specified for each load section as the power supply stop voltage in the voltage monitoring means related to the load section, respectively. And.

  According to the present invention, the battery characteristics indicating the relationship between the discharge capacity, the discharge current, and the end voltage of the battery by setting the backup time in the order of priority determined according to the importance of the plurality of load units. Based on the information, a power supply stop voltage capable of securing a backup time for each load unit is determined. Thereby, power supply control according to the battery characteristics of the battery can be performed, and a more important load can be backed up reliably.

  In addition, according to the present invention, the power supply stop voltage capable of securing the backup time of each load unit is determined based on the temperature characteristic information indicating the battery capacity for each battery temperature. In addition, it is possible to reliably back up loads with higher importance.

  In addition, according to the present invention, the secondary power supply voltage can be secured based on the cycle characteristic information indicating the battery capacity for each charge / discharge frequency of the secondary battery. While performing power supply control according to the cycle characteristics of the battery, it is possible to reliably back up a more important load.

  Exemplary embodiments of a power supply control device, a power supply control method, and an image forming apparatus according to the present invention will be explained below in detail with reference to the accompanying drawings.

[First Embodiment]
FIG. 1 is a block diagram illustrating a hardware configuration of the image forming apparatus 100 according to the present embodiment. As shown in FIG. 1, the image forming apparatus 100 has a configuration in which a controller 10 and an engine unit (Engine) 60 are connected by a PCI (Peripheral Component Interconnect) bus. The controller 10 is a controller that controls the entire image forming apparatus 100, drawing (image formation), communication, input from the operation unit 21, and image display on the display unit 22. The engine unit 26 is an image forming unit such as a printer engine that can be connected to the PCI bus 27, and is, for example, a monochrome plotter, a one-drum color plotter, a four-drum color plotter, or a fax unit. The engine unit 26 includes an image processing part such as error diffusion and gamma conversion in addition to a so-called engine part such as a plotter for forming an image on a predetermined recording medium.

  The controller 10 includes a CPU 11, a system memory (MEM-P) 12, a north bridge (NB) 13, a south bridge (SB) 14, an ASIC (Application Specific Integrated Circuit) 16, and a local memory (MEM-C). 17, a hard disk drive (HDD) 18, and an RTC (Real-Time Clock), and the north bridge (NB) 13 and the ASIC 16 are connected by an AGP (Accelerated Graphics Port) bus 15. The MEM-P 12 further includes a ROM (Read Only Memory) 121 and a RAM (Random Access Memory) 122.

  The CPU 11 controls the entire image forming apparatus 100 in an integrated manner, has a chip set composed of MEM-P 12, NB 13 and SB 14, and is connected to other devices via this chip set.

  The NB 13 is a bridge for connecting the CPU 11 to the MEM-P 12, SB 14, and AGP 15, and includes a memory controller that controls reading and writing to the MEM-P 12, a PCI master, and an AGP target.

  The MEM-P 12 is a system memory for holding various information related to the operation of the image forming apparatus 100, and includes a ROM 121 and a RAM 122. The ROM 121 is a read-only memory used as a memory for storing programs and data. The RAM 122 is an SRAM or the like, and is a volatile memory that can be written and read as a memory for developing programs and data, a memory for storing an address book, a memory for storing various setting information related to the image forming apparatus 100, and the like. It is.

  The SB 14 is a bridge for connecting the NB 13 to a PCI device and peripheral devices. The SB 14 is connected to the NB 13 via a PCI bus, and a network interface (I / F) unit and the like are also connected to the PCI bus.

  The AGP 15 is a bus interface for a graphics accelerator card proposed for speeding up graphics processing. The AGP 15 speeds up the graphics accelerator card by directly accessing the MEM-P 12 with high throughput. .

  The ASIC 16 is an IC (Integrated Circuit) for image processing applications having hardware elements for image processing, and has a function as a bridge for connecting the AGP 15, PCI bus, MEM-C 17, and HDD 18. The ASIC 16 includes a PCI target and an AGP master, an arbiter (ARB) that forms the core of the ASIC 16, a memory controller that controls the MEM-C 17, and a plurality of DMACs (Direct Memory) that perform image data rotation and the like using hardware logic. Access Controller) and a PCI unit that performs data transfer between the engine unit 60 via the PCI bus. The ASIC 16 is connected to an FCU (Fax Control Unit) 23, a USB (Universal Serial Bus) 24, an IEEE 1394 (the Institute of Electrical and Electronics Engineers 1394) interface 25, and the like via a PCI bus.

  The MEM-C 17 is a DRAM or the like, and is a volatile storage unit used as a copy image buffer, a code buffer, a fax data buffer, or the like. The HDD 18 is a storage for storing image data, programs, font data, and forms. The RTC 19 is a timer circuit provided for a clock function that performs timekeeping.

  FIG. 2 is a block diagram illustrating a configuration of the power supply control device 30 included in the image forming apparatus 100. As shown in FIG. 2, the power supply control device 30 includes a main power supply 31, a charging circuit 32, an auxiliary power supply 33, a switching circuit 34, power supply units 35, 36, and 37, and a power supply stop voltage setting unit 38.

  Here, the loads A, B, and C are any three of the plurality of power load units included in the image forming apparatus 100, and are set as backup targets by the auxiliary power source 33 when the main power source 31 is off. It will be. In this embodiment, the load A is the RAM 122, the load B is the RTC 19 for timekeeping, and the load C is the MEM-C17. However, the present invention is not limited to this mode. The number of power load units to be backed up is not limited to this mode, and an arbitrary number can be set. In this case, it is assumed that a power feeding unit is provided for each load.

  The loads A, B, and C have backup priority levels and predetermined backup times for maintaining functions, and load setting information that associates these values with the current consumption of each load. Is stored in the MEM-P12. Here, the priority order and backup time for each load are preferably set according to the importance of the image forming apparatus 100 such as the function and role of each load.

  For example, in the case of the image forming apparatus 100, it is preferable to give the highest priority to the backup of the RAM 122 (load A) that stores various setting information related to the address book and the image forming apparatus 100, and the backup time is as long as possible. Preferably there is. In addition, since the RTC (load B) that performs timekeeping must always function, it is given priority after the load A, and the current consumption is lower than other loads, so a relatively long backup time is set. It is possible. Further, the MEM-C17 (load C) used as a fax data buffer or the like is preferably backed up, but its priority is lower than the loads A and B, and the current consumption is higher than other loads. In comparison with the loads A and B, the backup time is preferably short.

  Here, FIG. 3 is a diagram showing an example of the load setting information, and the priority order, the backup time, and the current consumption are registered in association with each load. Note that the priority order and the backup time of each load may be set in advance in the load setting information, or may be set sequentially from the user via the operation unit 21 during power supply stop voltage setting processing described later. It is good.

  Returning to FIG. 2, the main power supply 31 supplies power supplied from an external commercial power supply (AC power supply) to each unit of the image forming apparatus 100 according to switching of a power ON / OFF switch of the image forming apparatus 100 (not shown). It is the power supply device supplied to.

  The charging circuit 32 supplies power from the main power supply 31 to the auxiliary power supply 33 and charges the auxiliary power supply 33. Note that the charging circuit 32 holds the auxiliary power supply 33 in a fully charged state when the main power supply 31 is supplied with power.

  The auxiliary power source 33 is composed of a chargeable / dischargeable secondary battery such as a lithium ion battery, and loads A and B are charged (charged) by the charging circuit 32 via the power supply units 35, 36 and 37, respectively. , C.

The switching circuit 34 switches the power supply to the power supply units 35, 36, and 37 from the main power supply 31 to the auxiliary power supply 33 according to the power supply state of the main power supply 31. Specifically, the switching circuit 34 maintains that the power supplied from the main power supply 31 is supplied to the power supply units 35, 36, and 37 when the main power supply 31 is turned on, and when the main power supply 31 is turned off, Switching is performed so that power is supplied from the auxiliary power source 33 to the power supply units 35, 36, and 37.

  The power supply unit 35 includes a switch 351 and a voltage monitoring circuit 352 and supplies power supplied from the main power supply 31 or the auxiliary power supply 33 to the load A. Here, the switch 351 is a switch circuit that performs on / off control of power supply to the load A in accordance with the control of the voltage monitoring circuit 352. It is assumed that it is normally in an on state. When the voltage monitoring circuit 352 monitors the voltage applied to the load A and determines that this voltage has reached the power supply stop voltage set by the power supply stop voltage setting unit 38, the voltage monitoring circuit 352 controls the switch 351 to the off state, The power supply to the load A is stopped.

  Similar to the power supply unit 35, the power supply unit 36 includes a switch 361 and a voltage monitoring circuit 362, and supplies power supplied from the main power supply 31 or the auxiliary power supply 33 to the load B. Here, the switch 361 is a switch circuit that performs on / off control of power supply to the load B in accordance with the control of the voltage monitoring circuit 362. It is assumed that it is normally in an on state. When the voltage monitoring circuit 362 monitors the voltage applied to the load B and determines that this voltage has reached the power supply stop voltage set by the power supply stop voltage setting unit 38, the voltage monitoring circuit 362 controls the switch 361 to the OFF state, Power supply to the load B is stopped.

  Similar to the power supply unit 35, the power supply unit 37 includes a switch 371 and a voltage monitoring circuit 372, and supplies power supplied from the main power supply 31 or the auxiliary power supply 33 to the load B. Here, the switch 371 is a switch circuit that performs on / off control of power supply to the load C in accordance with the control of the voltage monitoring circuit 372. It is assumed that it is normally in an on state. When the voltage monitoring circuit 372 monitors the voltage applied to the load C and determines that this voltage has reached the power supply stop voltage set by the power supply stop voltage setting unit 38, the voltage monitoring circuit 372 controls the switch 371 to be turned off, Power supply to the load B is stopped.

  The power supply stop voltage setting unit 38 is a control unit realized by cooperation of the CPU 11 of FIG. 1 and a predetermined program stored in advance in the ROM 121. The power supply stop voltage setting unit 38 derives the power supply stop voltage from the backup time set according to the priority order of the loads A, B, and C based on the battery capacity of the auxiliary power supply 33, and the corresponding voltage monitoring circuit 352, 362 and 372 are set.

  Hereinafter, the operation of the power supply stop voltage setting unit 38 will be described with reference to FIG. Here, FIG. 3 is a flowchart showing the procedure of the power supply stop voltage setting process executed by the power supply stop voltage setting unit 38. In this process, a mode in which the backup time is input via the operation unit 21 for each load (loads A, B, and C) registered in the load setting information will be described.

  First, the power supply stop voltage setting unit 38 determines the battery capacity D of the auxiliary power supply 33 (step S11). Here, the battery capacity D of the auxiliary power source 33 may be determined based on the voltage value applied from the auxiliary power source 33. In the case where the fully charged state is maintained as in the present embodiment, the value of the battery capacity D may be stored in the MEM-P 12 and read from the MEM-P 12. In this case, the battery capacity D stored in the MEM-P 12 is a value (mAh) when discharged to the discharge start voltage of the auxiliary power source 33 under the temperature and current value (standard load current) recommended by the manufacturer. Shall.

  Subsequently, the power supply stop voltage setting unit 38 executes a backup time setting process for setting a backup time for each load (step S12). Hereinafter, the backup time setting process in step S12 will be described with reference to FIG.

  FIG. 5 is a diagram showing the procedure of the backup time setting process. First, the power supply stop voltage setting unit 38 sets a variable n representing a priority order to “1” and initializes a variable F representing a sum of power consumption described later to “0” (step S1201).

  Next, when receiving the backup time input via the operation unit 21, the power supply stop voltage setting unit 38 sets the load setting information as the backup time of the load with priority n (step S <b> 1202). For example, when n = 1, priority 1 is set in the load setting information as the backup time of the load A (RAM 122). At this time, it is also possible to accept the instruction information for instructing the load with the priority order n from the user via the operation unit 21.

  Subsequently, the power supply stop voltage setting unit 38 reads the current consumption f of the load with priority n from the load setting information (step S1203), and calculates the backup time × f, thereby calculating the power consumption for the backup time. (Step S1204).

  Next, when the power supply stop voltage setting unit 38 calculates the total current consumption F (F = F + f) related to the loads from priority 1 to n (step S1205), is the value of F equal to or less than the value of the battery capacity D? It is determined whether or not (step S1206). In the present embodiment, a mode in which the value of D is directly compared with the value of F is shown. However, the present invention is not limited to this. For example, the result of multiplying D by a predetermined ratio (for example, 80%) is obtained. It is good also as an aspect compared with F.

  In step S1206, when it is determined that the value of F exceeds the value of D (step S1206; No), the power supply stop voltage setting unit 38 notifies that and whether to reset the backup time or not. Information for prompting confirmation is displayed on the display unit 22 (step S1207), and the process waits until an instruction signal is input via the operation unit 21 (step S1208).

  If an instruction signal for instructing resetting of the backup time is received via the operation unit 21 (step S1208; Yes), the power supply stop voltage setting unit 38 returns to the process of step S1201. Return.

  In step S1208, when an instruction signal instructing not to reset the backup time is received (step S1208; No), the power supply stop voltage setting unit 38 sets the remaining battery in the load having priority n. After setting the backup time corresponding to the capacity (remaining battery capacity), that is, the calculation result of (D-F-f) / f, to the load setting information as the backup time of priority n (step S1209), FIG. The process proceeds to step S13. If the processing in step S1209 is executed before setting the backup time for all loads registered in the load setting information, the backup time is not set for the remaining loads, that is, loads with low priority. And

  On the other hand, if it is determined in step S1206 that the value of F is equal to or less than the value of D (step S1206; Yes), has the power supply stop voltage setting unit 38 set the backup time for all the loads registered in the load setting information? It is determined whether or not (step S1210). If it is determined that an unset load remains (step S1210; No), the power supply stop voltage setting unit 38 adds 1 to n and lowers the priority by 1 (step S1211). ), The process returns to step S1202.

  If it is determined in step S1210 that the backup time has been set for all the loads (step S1210; Yes), the power supply stop voltage setting unit 38 calculates the D−F, so that there is a remainder in the battery capacity D. It is determined whether or not (step S1212). Here, when it is determined that the battery capacity D does not have a surplus (step S1212; No), the process immediately proceeds to the process of step S13 in FIG.

  On the other hand, when it is determined in step S1212 that there is a surplus in the battery capacity D (step S1212; Yes), the power supply stop voltage setting unit 38 sets the backup time for the load with the priority order 1 set in the load setting information. Then, the time corresponding to the remaining battery capacity is added (step S1213), and the process proceeds to step S13 in FIG.

  Specifically, the power supply stop voltage setting unit 38 derives a time corresponding to the remaining battery capacity by calculating “(D−F) / current consumption f applied to the load of priority 1”. In this embodiment, the backup time corresponding to the remaining battery capacity is assigned to the load with the highest priority. However, the present invention is not limited to this, and may be assigned to each load at a ratio according to the priority. Good. Moreover, it is good also as an aspect which does not allocate the backup time corresponded to remaining battery capacity.

  In this way, by performing the backup time setting process shown in FIG. 5, the backup time of each load registered in the load setting information is set or updated (see FIG. 3).

  Returning to FIG. 4, the power supply stop voltage setting unit 38 initializes a variable Z, which will be described later, to 0 (step S <b> 13), and then, based on the backup time set in the process of step S <b> 12, Then, the processing is sequentially performed from the load with the short backup time (step S14).

  Subsequently, the power supply stop voltage setting unit 38 calculates a value X obtained by subtracting the backup time of the load to be processed last time from the backup time of the load to be processed this time in the process of step S14 (step S15). .

  Next, the power supply stop voltage setting unit 38 calculates the sum of the current consumption of each load that has been processed up to the previous time from the sum of the current consumption of each load for which the backup time is set among the loads registered in the load setting information. A value Y is calculated by subtracting (step S16).

  Subsequently, the power supply stop voltage setting unit 38 multiplies X calculated in step S15 by Y calculated in step S16, thereby removing the current consumption for the remaining load after removing the load whose backup time has ended. z is calculated (step S17). Next, the power supply stop voltage setting unit 38 calculates Z = Z + z to derive the accumulated power consumption Z necessary for backing up the load to be processed for the set backup time (step S18).

  Next, the power supply stop voltage setting unit 38 refers to the battery characteristic information representing the relationship between the discharge capacity of the auxiliary power source 33 stored in advance in the MEM-P 12, the discharge current, and the end voltage, and the current consumption Y An end voltage that can sometimes use the discharge capacity of the accumulated power consumption Z is specified as a power supply stop voltage (step S19). Battery characteristic information will be described later.

  Next, the power supply stop voltage setting unit 38 sets the power supply stop voltage specified in step S19 in the voltage monitoring circuit corresponding to the load to be processed (step S20), and the process proceeds to step S21. For example, when the power supply stop voltage applied to the load A is specified as the processing target load, the power supply stop voltage is set in the voltage monitoring circuit 352.

  In subsequent step S21, the power supply stop voltage setting unit 38 determines whether or not all the loads for which the backup time is set among the loads registered in the load setting information have been processed (step S21). Here, when it is determined that there is an unprocessed load (step S21; No), the power supply stop voltage setting unit 38 returns to the process of step S14 and sets the next load as a processing target. If it is determined that all loads are to be processed (step S21; Yes), this process is terminated.

  Hereinafter, the operation of the loop processing of steps S14 to S19 will be specifically described based on the load setting information shown in FIG. First, in the first loop process, the power supply stop voltage setting unit 38 sets the load A having the shortest backup time as a processing target (step S14). Subsequently, the power supply stop voltage setting unit 38 derives X = 12h and Y = 5.0 mA, respectively, because there is no load that has been processed last time (steps S15 and S16). Then, the power supply stop voltage setting unit 38 derives z = 60 mAh by calculating X × Y (step S17), and derives Z = 60 mAh because Z is initialized to 0 (step S18). ).

  Here, the battery characteristic information referred to by the power supply stop voltage setting unit 38 in step S19 will be described. FIG. 6 is a diagram showing an example of battery characteristic information stored in the MEM-P 12 in advance. As shown in the figure, the battery characteristic information represents the relationship between the discharge capacity of the auxiliary power source 33, the discharge current, and the end voltage.

  The “discharge capacity” represents the amount of power (mAh) that can be discharged by the auxiliary power source 33 and corresponds to the accumulated power consumption Z. The “discharge current” represents the amount of current supplied by the auxiliary power supply 33 and corresponds to the consumption current Y. The “end voltage” is a minimum value of the discharge voltage at which the auxiliary power source 33 can safely discharge.

  As shown in FIG. 6, the auxiliary power supply 33 has a characteristic that the discharge capacity starts to decrease when the discharge current exceeds the standard load current of 0.1 mA, and the discharge capacity decreases as the supply current increases. (Discharge load characteristics).

  For example, when the final voltage is 2.5 V, the discharge capacity is 100 mAh when the discharge current is 0.1 mA, and the discharge capacity is 60 mAh when the discharge current is 5.0 mA. That is, it can be seen that when the discharge current is 5.0 mA, a discharge capacity of 1000 mAh−60 mAh = 40 mAh cannot be used compared to when the final voltage is 2.5V.

  Further, when the end voltage is lowered, for example, when the discharge current is 0.1 mA, the discharge capacity is 100 mAh when the end voltage is 2.5 V, and the discharge capacity is 120 mAh when the end voltage is 2.0 V. In other words, it can be seen that by changing the end voltage from 2.5V to 2.0V, a large discharge capacity of 20 mAh can be used.

  In step S19, the power supply stop voltage setting unit 38 specifies, as the power supply stop voltage, a stop voltage that can use the discharge capacity of the accumulated power consumption Z when the current consumption Y is based on the battery characteristic information. Specifically, in the case of the first loop, since Y = 5.0 mA and Z = 60 mAh, the power supply stop voltage setting unit 38 specifies the end voltage 2.5 V of the graph corresponding to these values as the power supply stop voltage. To do. Then, the power supply stop voltage setting unit 38 sets the power supply stop voltage 2.5 V in the voltage monitoring circuit 352 corresponding to the load A to be processed (step S20), and ends the first loop process.

  In the second loop process, the power supply stop voltage setting unit 38 sets the load B having the next smallest backup time as a processing target (step S14). Subsequently, the power supply stop voltage setting unit 38 sets 600h, which is obtained by subtracting the backup time 12h of the load A, which is the previous processing target, from the backup time 612h of the load B as X (step S15). Further, the power supply stop voltage setting unit 38 sets Y to 0.1 mA obtained by subtracting the power consumption 4.9 mA of the load A that has been processed up to the previous time from the total power consumption 5.0 mA of all loads (step). S16).

  Then, the power supply stop voltage setting unit 38 derives z = 60 mAh by calculating X × Y (step S17), and derives Z = 120 mAh by calculating Z = Z + z = 60 mAh + 60 mAh (step S18). ).

  In subsequent step S19, the power supply stop voltage setting unit 38 uses, as the power supply stop voltage, a final voltage of 2.0 V that can use a discharge capacity of 120 mAh when the consumption current is 0.1 mA from the battery characteristic information. Identify. Then, the power supply stop voltage setting unit 38 sets the power supply stop voltage 2.0V in the voltage monitoring circuit 362 corresponding to the load B to be processed (step S20), and ends the second loop process.

  In the third loop process, the power supply stop voltage setting unit 38 sets the load C having the next smallest backup time as a processing target (step S14). Subsequently, the power supply stop voltage setting unit 38 sets 1000h, which is obtained by subtracting the backup time 612h of the load B, which is the previous processing target, from the backup time 1612h of the load C as X (step S15). Further, the power supply stop voltage setting unit 38 subtracts the total power consumption 4.99 mA of the loads A and B to be processed from the total 5.0 mA of the power consumption of all loads, and sets 0.01 mA as Y. (Step S16).

  Then, the power supply stop voltage setting unit 38 derives z = 10 mAh by calculating X × Y (step S17) and derives Z = 130 mAh by calculating Z = Z + z = 120 mAh + 10 mAh (step S18). ).

  In subsequent step S19, the power supply stop voltage setting unit 38 uses, as the power supply stop voltage, the end voltage 1.8V that can use the discharge capacity of 130 mAh when the consumption current is 0.01 mA from the battery characteristic information. Identify. Then, the power supply stop voltage setting unit 38 sets the power supply stop voltage 1.8V in the voltage monitoring circuit 372 corresponding to the load C to be processed (step S20), ends the third loop process, and supplies power. The stop voltage setting process is terminated. Note that the power supply stop voltage may not be set for the load having the longest backup time.

  In this way, since the power supply stop voltage can be set in each voltage monitoring circuit based on the characteristics of the auxiliary power supply 33, power supply control according to the characteristics of the auxiliary power supply 33 can be performed. Hereinafter, the operation of the voltage monitoring circuit will be described with reference to FIG.

  FIG. 7 is a flowchart showing a procedure of voltage monitoring processing of the voltage monitoring circuit 352. Although the voltage monitoring circuit 352 will be described in this processing, the same voltage monitoring processing is performed on the voltage monitoring circuit 362 and the voltage monitoring circuit 372 based on the applied voltages from the switches 361 and 371.

  First, the voltage monitoring circuit 352 constantly monitors the voltage applied to the load A from the switch 351 or every predetermined time (step S31), and the applied voltage is equal to or lower than the power supply stop voltage set by the power supply stop voltage setting unit 38. It is determined whether or not (step S32). Here, when it is determined that the applied voltage exceeds the power supply stop voltage (step S32; No), the process returns to the process of step S31 again.

  On the other hand, when it is determined in step S32 that the applied voltage is equal to or lower than the power supply stop voltage (step S32; Yes), the power supply to the load A is stopped by controlling the switch 351 to the off state (step S33). ), This process is terminated.

  FIG. 8 is a diagram showing the discharge characteristics of the auxiliary power source 33. Here, the vertical axis represents the battery voltage of the auxiliary power supply 33, and the horizontal axis represents the passage of time. In the figure, power is supplied from the auxiliary power source 33 to the loads A, B, and C in the period L1, and the battery voltage decreases with time. Here, when the battery voltage of the auxiliary power supply 33 reaches the supply stop voltage of the load C, the switch 371 is switched to the OFF state by the control of the voltage monitoring circuit 372, and the power supply to the load C is stopped. In addition, the waveform shown by P1 in the figure is a noise component produced by the voltage fluctuation accompanying the power supply stop to the load C.

  In the period L2, power is supplied from the auxiliary power source 33 to the loads A and B, and the battery voltage decreases with time. Here, when the battery voltage of the auxiliary power supply 33 reaches the supply stop voltage of the load A, the switch 351 is switched to the OFF state by the control of the voltage monitoring circuit 352, and the power supply to the load A is stopped. In addition, the waveform shown by P2 in the figure is a noise component generated due to voltage fluctuation accompanying the stoppage of power supply to the load A.

  In the period L3, power is supplied only from the auxiliary power source 33 to the load B, and the battery voltage decreases with time. Here, when the battery voltage of the auxiliary power supply 33 reaches the supply stop voltage of the load B, the switch 361 is switched to the OFF state by the control of the voltage monitoring circuit 362, and the power supply to the load B is stopped.

  As described above, according to the present embodiment, the backup time is set in the order of priority determined according to the importance of the plurality of load units, the discharge capacity of the auxiliary power source, the discharge current, the end voltage, On the basis of the battery characteristic information indicating the relationship, a power supply stop voltage capable of securing a backup time for each load unit is determined. Thereby, power supply control according to the battery characteristics of the auxiliary power supply can be performed, and a more important load can be reliably backed up.

  Note that each load to be backed up by the auxiliary power supply 33 is not limited to a single component, and a plurality of components may be handled as one load. For example, as illustrated in FIG. 9, the DRAM 171 and the power supply circuit 172 that generates driving power for driving the DRAM 171 may be handled as a single load A. In this case, the voltage monitoring circuit 372 monitors the voltage applied from the switch 371 to the power supply circuit 172.

  Moreover, although the aspect which comprised the auxiliary power supply with the secondary battery was demonstrated in this embodiment, it is good not only as this but the aspect which comprises an auxiliary power supply from a primary battery. In this case, it is not necessary to supply power from the main power source to the auxiliary power source. Therefore, the charging circuit 32 may be removed.

[Second Embodiment]
Next, a second embodiment of the image forming apparatus according to the present invention will be described. In addition, about the element similar to 1st Embodiment mentioned above, it shows using the same code | symbol and the description is abbreviate | omitted suitably.

  In the first embodiment, the battery capacity D stored in advance in the MEM-P 12 is used. However, actually, the battery capacity D and the discharge characteristics of the auxiliary power source 33 vary depending on the temperature of the environment to be used. I know that. Specifically, the battery capacity D decreases as the temperature decreases from the recommended temperature, and the battery capacity D increases as the temperature increases. Therefore, the power supply control device 40 according to the present embodiment executes power supply control according to the characteristics of the auxiliary power supply 33 by setting the battery capacity D and the power supply stop voltage according to the temperature of the auxiliary power supply 33.

  FIG. 10 is a block diagram illustrating a configuration of the power supply control device 40. As shown in FIG. 10, the power supply control device 40 includes a temperature detection circuit 41, a power supply stop voltage setting unit, in addition to the main power supply 31, the charging circuit 32, the auxiliary power supply 33, the switching circuit 34, and the power supply units 35, 36, and 37. 42 is provided.

  The temperature detection circuit 41 is a temperature detection device arranged in the vicinity of the auxiliary power supply 33, detects the temperature of the auxiliary power supply 33, and outputs the result to the power supply stop voltage setting unit 42.

  The power supply stop voltage setting unit 42 has the same function as that of the power supply stop voltage setting unit 38 and, based on the temperature of the auxiliary power supply 33 detected by the temperature detection circuit 41, calculates the battery capacity D corresponding to this temperature to the MEM. -It specifies from the temperature characteristic information memorize | stored in P12. In addition, the power supply stop voltage setting unit 42 specifies the power supply stop voltage applied to each load from the battery characteristic information prepared for each temperature based on the temperature of the auxiliary power supply 33 detected by the temperature detection circuit 41.

  FIG. 11 is a diagram illustrating an example of temperature characteristic information stored in the MEM-P 12. As shown in the figure, the temperature and the battery capacity D of the auxiliary power source 33 corresponding to each temperature are stored in association with each other. The power supply stop voltage setting unit 42 refers to the temperature characteristic information and determines the battery capacity D corresponding to the temperature of the auxiliary power supply 33 detected by the temperature detection circuit 41. In addition, although the aspect which represented temperature characteristic information in the graph format was illustrated in FIG. 11, it is good also as an aspect represented not only in this but a table format etc.

  The MEM-P 12 stores a plurality of pieces of battery characteristic information indicating the characteristics of the auxiliary power source 33 corresponding to each temperature. Each battery characteristic information represents the relationship between the discharge capacity, discharge current, and end voltage of the auxiliary power source 33 at each temperature, similarly to the battery characteristic information described with reference to FIG. .

  Hereinafter, the operation of the power supply stop voltage setting unit 42 will be described with reference to FIG. FIG. 12 is a flowchart showing the procedure of the power supply stop voltage setting process executed by the power supply stop voltage setting unit 42. In this process, a mode in which the backup time is input via the operation unit 21 for each load (loads A, B, and C) registered in the load setting information will be described.

  First, when the power supply stop voltage setting unit 42 receives the temperature of the auxiliary power supply 33 detected by the temperature detection circuit 41 (step S41), the temperature of the auxiliary power supply 33 is referred to by referring to the temperature characteristic information stored in the MEM-P12. Is determined (step S42).

  Subsequently, the power supply stop voltage setting unit 42 executes a backup time setting process for setting a backup time for each load (step S43). The backup time setting process in step S43 is the same as the backup time setting process in step S12 described in FIG.

  Next, the power supply stop voltage setting unit 42 initializes the variable Z to 0 (step S44), and then, based on the backup time set in the process of step S43, the ascending order of the backup time, that is, the backup time The target is sequentially processed from a short load (step S45).

  Subsequently, the power supply stop voltage setting unit 42 calculates a value X obtained by subtracting the backup time of the load to be processed last time from the backup time of the load set to be processed this time in the process of step S45 (step S46). ).

  Next, the power supply stop voltage setting unit 42 calculates the sum of the current consumption of each load that has been processed up to the previous time from the sum of the current consumption of the loads for which the backup time is set among the loads registered in the load setting information. The subtracted value Y is calculated (step S47).

  Subsequently, the power supply stop voltage setting unit 42 multiplies X calculated in step S46 and Y calculated in step S47, thereby removing the load for which the backup time has ended and removing the current consumption for the remaining load. z is calculated (step S48). Next, the power supply stop voltage setting unit 42 calculates Z = Z + z to derive the accumulated power consumption Z necessary for backing up the load to be processed for the set backup time (step S49).

  Next, the power supply stop voltage setting unit 42 refers to the battery characteristic information corresponding to the temperature detected by the temperature detection circuit 41 among the plurality of battery characteristic information stored in the MEM-P 12 in advance, and An end voltage that can sometimes use the discharge capacity of the accumulated power consumption Z is specified as a power supply stop voltage (step S50).

  Next, the power supply stop voltage setting unit 42 sets the power supply stop voltage specified in step S50 in the voltage monitoring circuit corresponding to the load to be processed (step S51), and the process proceeds to step S52.

  In subsequent step S52, the power supply stop voltage setting unit 42 determines whether or not all the loads set in the backup time among the loads registered in the load setting information have been processed (step S52). Here, when it is determined that there is an unprocessed load (step S52; No), the power supply stop voltage setting unit 42 returns to the process of step S45 and sets the next load as a processing target. If it is determined that all loads are to be processed (step S52; Yes), the present process is terminated.

  The power supply stop voltage setting unit 42 adjusts the power supply stop voltage applied to each load based on the temperature of the auxiliary power supply 33 input in real time from the temperature detection circuit 41 when the main power supply 31 is turned on. Hereinafter, the operation of the power supply stop voltage setting unit 42 will be described with reference to FIGS. FIG. 13 is a flowchart showing the procedure of the power supply stop voltage adjustment process executed by the power supply stop voltage setting unit 42.

  First, when the power supply stop voltage setting unit 42 receives the temperature of the auxiliary power supply 33 detected by the temperature detection circuit 41 when the main power supply 31 is on (step S61), the temperature characteristic information stored in the MEM-P12 is displayed. The battery capacity D corresponding to the temperature of the auxiliary power source 33 is determined with reference to step S62.

  Subsequently, the power supply stop voltage setting unit 42 executes a backup time adjustment process for adjusting the backup time of each load (step S63). Hereinafter, the backup time adjustment processing in step S63 will be described with reference to FIG.

  FIG. 14 is a flowchart showing the procedure of the backup time adjustment process. First, the power supply stop voltage setting unit 42 calculates the product of the current consumption and the backup time for each load registered in the load setting information, and calculates the sum F (step S631).

  Next, the power supply stop voltage setting unit 42 compares D and F determined in step S62, and determines whether the difference between the values is within a predetermined value (for example, 50 Ah) (step S632). Here, when it is determined that the difference between D and F is within the predetermined value (step S632; Yes), the power supply stop voltage setting unit 42 ends the backup time adjustment process and ends the power supply stop voltage adjustment process. To do.

  In Step S632, when it is determined that the difference between D and F exceeds the predetermined value (Step S632; No), the power supply stop voltage setting unit 42 determines whether the value of D exceeds the value of F. Is determined (step S633).

  In Step S633, when it is determined that the value of D exceeds the value of F (Step S633; Yes), the power supply stop voltage setting unit 42 prioritizes the difference value obtained by subtracting F from D in the load setting information. By dividing by the consumption current of the load with the highest rank, the time during which the load with the highest priority can be backed up with the discharge capacity corresponding to D−F is calculated (step S634).

  Next, the power supply stop voltage setting unit 42 adds the time calculated in step S634 to the backup time of the load with the highest priority registered in the load setting information (step S635), and proceeds to the process of step S64 in FIG. And migrate. In this process, the surplus discharge capacity of DF is used only for the load with the highest priority. However, the present invention is not limited to this. For example, as an aspect for assigning each load at a ratio according to the priority. Also good.

  On the other hand, when it is determined in step S633 that the value of D is less than the value of F (step S633; No), the power supply stop voltage setting unit 42 registers the difference value obtained by subtracting D from F in the load setting information. The time to be subtracted from the load with the lowest priority is calculated by dividing by the current consumption of the load with the lowest priority (step S636).

  Next, the power supply stop voltage setting unit 42 subtracts the time calculated in step S636 from the backup time of the load with the lowest priority registered in the load setting information (step S637), and proceeds to the process of step S64 in FIG. And migrate. In this process, the discharge capacity for the shortage of FD is covered from the load with the lowest priority. However, the present invention is not limited to this. For example, the discharge capacity is covered from each load at a rate according to the priority. Also good.

  Returning to FIG. 13, the power supply stop voltage setting unit 42 initializes the variable Z to 0 (step S <b> 64), and then, based on the backup time set in step S <b> 63, ascending order of the backup time, that is, the backup The processing is sequentially performed from a load with a short time (step S65). Hereinafter, the processing of steps S66 to S72 is the same as the processing of steps S46 to S52 described above, and thus the description thereof is omitted.

  As described above, according to the present embodiment, the backup time is set in the order of priority determined according to the importance of the plurality of load units, the discharge capacity of the auxiliary power source, the discharge current, the end voltage, On the basis of the battery characteristic information indicating the relationship, a power supply stop voltage capable of securing a backup time for each load unit is determined. Thereby, power supply control according to the battery characteristics of the auxiliary power supply can be performed, and a more important load can be reliably backed up.

  Also, based on the temperature characteristic information indicating the battery capacity for each temperature of the auxiliary power supply, to determine the power supply stop voltage that can ensure the backup time of each load unit, power supply control according to the temperature characteristics of the auxiliary power supply is performed. In addition, it is possible to reliably back up more important loads.

[Third Embodiment]
Next, a third embodiment of the image forming apparatus according to the present invention will be described. In addition, about the element similar to 1st Embodiment mentioned above, it shows using the same code | symbol and the description is abbreviate | omitted suitably.

  In the first embodiment, the battery capacity D stored in advance in the MEM-P 12 is used. However, in actuality, the performance of the auxiliary power supply 33 increases as the number of charge / discharge cycles (number of cycles) of the auxiliary power supply 33 increases. Therefore, the battery capacity D and discharge characteristics of the auxiliary power supply 33 change. Specifically, since the depth of discharge becomes shallower as the number of cycles increases, the battery capacity D decreases. Therefore, the power supply control device 50 according to the present embodiment executes power supply control according to the characteristics of the auxiliary power supply 33 by setting the battery capacity D according to the number of cycles of the auxiliary power supply 33.

  FIG. 15 is a block diagram illustrating a configuration of the power supply control device 50. As shown in FIG. 15, in addition to the main power supply 31, the charging circuit 32, the auxiliary power supply 33, the switching circuit 34, and the power supply units 35, 36, and 37, the power supply control device 50 includes a cycle number counting unit 51 and a power supply stop voltage setting. A portion 52 is provided.

  Each time the auxiliary power supply 33 is charged and discharged, the cycle number counting unit 51 counts the cumulative number of times and outputs the counted result to the power supply stop voltage setting unit 52.

  The power supply stop voltage setting unit 52 has the same function as that of the power supply stop voltage setting unit 38, and based on the number of cycles of the auxiliary power source 33 counted by the cycle number counting unit 51, the battery capacity D corresponding to this number of cycles. Is specified from the cycle characteristic information stored in the MEM-P12. In addition, the power supply stop voltage setting unit 52 specifies the power supply stop voltage applied to each load from the battery characteristic information prepared for each temperature based on the number of cycles of the auxiliary power supply 33 counted by the cycle number counting unit 51.

  FIG. 16 is a diagram illustrating an example of the cycle characteristic information stored in the MEM-P 12. As shown in the figure, the number of cycles and the battery capacity D of the auxiliary power source 33 corresponding to each number of cycles are stored in association with each other. The power supply stop voltage setting unit 52 refers to the cycle characteristic information and determines the battery capacity D corresponding to the number of cycles of the auxiliary power source 33 counted by the cycle number counting unit 51. In addition, in FIG. 16, although the aspect which represented cycle characteristic information in the graph format was illustrated, it is good also as an aspect represented not only in this but a table format etc.

  The MEM-P 12 stores a plurality of pieces of battery characteristic information representing the characteristics of the auxiliary power source 33 according to the number of cycles. Each battery characteristic information represents the relationship between the discharge capacity, discharge current, and end voltage of the auxiliary power source 33 at a predetermined number of cycles, similarly to the battery characteristic information described in FIG. To do.

  Hereinafter, the operation of the power supply stop voltage setting unit 52 will be described with reference to FIG. FIG. 17 is a flowchart showing the procedure of the power supply stop voltage setting process executed by the power supply stop voltage setting unit 52. In this process, a mode in which the backup time is input via the operation unit 21 for each load (loads A, B, and C) registered in the load setting information will be described.

  First, when the power supply stop voltage setting unit 52 receives the number of cycles of the auxiliary power supply 33 counted by the cycle number counting unit 51 (step S81), the power supply stop voltage setting unit 52 refers to the cycle characteristic information stored in the MEM-P12 and refers to the auxiliary power supply 33. The battery capacity D corresponding to the number of cycles is determined (step S82).

  Subsequently, the power supply stop voltage setting unit 52 executes a backup time setting process for setting a backup time for each load (step S83). The backup time setting process in step S83 is the same as the backup time setting process in step S12 described with reference to FIG.

  Next, the power supply stop voltage setting unit 52 initializes the variable Z to 0 (step S84), and then, based on the backup time set in the process of step S83, the ascending order of the backup time, that is, the backup time The processing is sequentially performed from a short load (step S85).

  Subsequently, the power supply stop voltage setting unit 52 calculates a value X obtained by subtracting the backup time of the load to be processed last time from the backup time of the load set as the current processing target in the process of step S85 (step S86). ).

  Next, the power supply stop voltage setting unit 52 calculates the sum of the current consumption of each load that has been processed up to the previous time from the sum of the current consumption of the loads for which the backup time is set among the loads registered in the load setting information. The subtracted value Y is calculated (step S87).

  Subsequently, the power supply stop voltage setting unit 52 multiplies X calculated in step S86 by Y calculated in step S87, thereby removing the current consumption for the remaining load after removing the load whose backup time has ended. z is calculated (step S88). Next, the power supply stop voltage setting unit 52 calculates Z = Z + z to derive the accumulated power consumption Z necessary for backing up the processing target load for the set backup time (step S89).

  Next, the power supply stop voltage setting unit 52 refers to the battery characteristic information corresponding to the number of cycles counted by the cycle number counting unit 51 among the plurality of pieces of battery characteristic information stored in advance in the MEM-P 12, and consumes current. An end voltage that can use the discharge capacity of the cumulative power consumption Z when Y is specified as a power supply stop voltage (step S90).

  Next, the power supply stop voltage setting unit 52 sets the power supply stop voltage specified in step S80 in the voltage monitoring circuit corresponding to the load to be processed (step S91), and the process proceeds to step S92.

  In subsequent step S92, the power supply stop voltage setting unit 52 determines whether or not all loads set with the backup time among the loads registered in the load setting information have been processed (step S92). Here, when it is determined that there is an unprocessed load (step S92; No), the power supply stop voltage setting unit 52 returns to the process of step S85 and sets the next load as a processing target. If it is determined that all loads are to be processed (step S92; Yes), this process is terminated.

  The power supply stop voltage setting unit 52 adjusts the power supply stop voltage applied to each load based on the number of cycles of the auxiliary power supply 33 input in real time from the cycle number counting unit 51 when the main power supply 31 is turned on. Hereinafter, the operation of the power supply stop voltage setting unit 52 will be described with reference to FIG.

  FIG. 18 is a flowchart illustrating a procedure of power supply stop voltage adjustment processing executed by the power supply stop voltage setting unit 52. First, when the power supply stop voltage setting unit 52 receives the number of cycles of the auxiliary power supply 33 counted by the cycle number counting unit 51 when the main power supply 31 is turned on (step S101), the cycle characteristics stored in the MEM-P12. With reference to the information, the battery capacity D corresponding to the number of cycles of the auxiliary power supply 33 is determined (step S102).

  Subsequently, the power supply stop voltage setting unit 52 executes a backup time adjustment process for adjusting the backup time of each load (step S103). The backup time adjustment process in step S103 is the same as the backup time setting process in step S63 described with reference to FIG. Moreover, since the process of step S104-112 is the same as the process of step S84-92 mentioned above, the description is abbreviate | omitted.

  As described above, according to this embodiment, the backup time is set in the order of priority according to the importance of each load unit, and the relationship between the discharge capacity of the auxiliary power supply, the discharge current, and the end voltage is shown. Based on the battery characteristic information, the power supply stop voltage that can secure the backup time of each load unit is determined. Thereby, power supply control according to the battery characteristics of the auxiliary power supply can be performed, and a more important load can be reliably backed up.

  In addition, based on the cycle characteristic information indicating the battery capacity for each charge / discharge frequency of the auxiliary power supply, the power supply stop voltage that can secure the backup time of each load unit is determined, so that the power supply according to the cycle characteristic of the auxiliary power supply is determined. In addition to performing control, it is possible to reliably back up more important loads.

  As mentioned above, although this invention has been demonstrated using the 1st-3rd embodiment, a various change or improvement can be added to embodiment mentioned above. Moreover, the structure and function demonstrated in the 1st-3rd embodiment mentioned above can be combined freely.

  For example, in the above-described embodiment, an example in which the power supply control device (30, 40, 50) is applied to the image forming device has been described. However, the present invention is not limited to this, and an information processing device such as a PC (Personal Computer) or a mobile phone It is good also as an aspect applied to mobile communication terminals, such as a container. In addition, when applied to a mobile communication terminal, the main power supply is not an essential component, and the power supply control device described above is applied by handling the power supply of the mobile communication terminal formed of a chargeable / dischargeable secondary battery as the auxiliary power supply 33. Is possible.

  As described above, the power supply control device, the power supply control method, and the image forming apparatus according to the present invention are effective when a plurality of loads are backed up by a single power source, and in particular, priorities according to the importance of each load. This is suitable when power supply control is performed based on the above.

It is the block diagram which showed the hardware constitutions of the image processing apparatus. It is the block diagram which showed the structure of the electric power feeding control apparatus concerning 1st Embodiment. It is the figure which showed an example of load setting information. It is the flowchart which showed the procedure of the electric power supply stop voltage setting process concerning 1st Embodiment. It is the figure which showed the procedure of the backup time setting process. It is the figure which showed an example of battery characteristic information. It is the flowchart which showed the procedure of the voltage monitoring process. It is the figure which showed the discharge characteristic of the auxiliary power supply. It is the figure which showed the structural example of load. It is the block diagram which showed the structure of the electric power feeding control apparatus concerning 2nd Embodiment. It is the figure which showed an example of temperature characteristic information. It is the flowchart which showed the procedure of the electric power supply stop voltage setting process concerning 2nd Embodiment. It is the flowchart which showed the procedure of the electric power feeding stop voltage adjustment process concerning 2nd Embodiment. It is the flowchart which showed the procedure of backup time adjustment processing. It is the block diagram which showed the structure of the electric power feeding control apparatus concerning 3rd Embodiment. It is the figure which showed an example of cycle characteristic information. It is the flowchart which showed the procedure of the electric power supply stop voltage setting process concerning 3rd Embodiment. It is the flowchart which showed the procedure of the electric power supply stop voltage adjustment process concerning 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Image forming apparatus 10 Controller 11 CPU
12 System memory (MEM-P)
121 ROM
122 RAM
13 North Bridge (NB)
14 South Bridge (SB)
15 AGP bus 16 ASIC
17 Local memory (MEM-C)
18 Hard disk drive (HDD)
19 RTC
21 Operation unit 22 Display unit 23 FCU
24 USB
25 IEEE1394 interface 26 Engine unit 27 PCI bus 30 Power supply control device 31 Main power supply 32 Charging circuit 33 Auxiliary power supply 34 Switching circuit 35 Power supply unit 351 Switch 352 Voltage monitoring circuit 36 Power supply unit 361 Switch 362 Voltage monitoring circuit 37 Power supply unit 371 Switch 372 Voltage Monitoring circuit 38 Power supply stop voltage setting unit 40 Power supply control device 41 Temperature detection circuit 42 Power supply stop voltage setting unit 50 Power supply control device 51 Cycle number counting unit 52 Power supply stop voltage setting unit

Claims (12)

Battery,
A plurality of load units that operate by power supplied from the battery;
A plurality of switch means for individually turning on / off the power supply from the battery to the load units;
A plurality of voltage monitoring means for individually monitoring the voltage applied to each load unit, and switching the switch means individually from an on state to an off state when the voltage reaches a predetermined power supply stop voltage;
First storage means for storing battery characteristic information indicating a relationship between the discharge capacity of the battery, the discharge current, and the end voltage;
A backup time setting means for preferentially setting a backup time from a load unit with a high priority based on a priority determined according to the importance of each load unit;
Based on the current consumption of each load unit and the backup time, the cumulative power consumption required until the backup time of each load unit expires is calculated, and the end voltage corresponding to the cumulative power consumption and current consumption of each load unit is calculated. End voltage specifying means for specifying from the battery characteristic information;
A stop voltage setting means for setting the stop voltage specified for each load section as the power supply stop voltage in the voltage monitoring means related to the load section;
A power supply control device comprising:   The power supply control device according to claim 1, wherein the backup time setting unit preferentially sets a backup time from a load unit having a high priority within a range of a battery capacity of the battery. Temperature detecting means for detecting the temperature of the battery;
Second storage means for storing temperature characteristic information indicating a battery capacity for each temperature of the battery;
Further comprising
The power supply control device according to claim 2, wherein the backup time setting unit determines the battery capacity of the battery from the temperature detected by the temperature detection unit based on the temperature characteristic information. The battery is a secondary battery,
A cycle number counting means for counting the number of times the battery is charged and discharged;
Third storage means for storing cycle characteristic information indicating the battery capacity for each charge / discharge cycle of the battery;
Further comprising
3. The power supply control device according to claim 2, wherein the backup time setting unit determines the battery capacity of the battery from the number of times of charging / discharging counted by the cycle number counting unit based on the cycle characteristic information. .   The backup time setting means calculates a total power consumption obtained by adding the power consumption of all the load units based on the current consumption of each load unit and the backup time, and calculates the total power consumption and the determined battery capacity. The power feeding control device according to claim 3 or 4, wherein when the difference value is equal to or greater than a predetermined value, the backup time of each load unit is adjusted.   When the backup time setting means determines that the battery capacity exceeds the total power consumption, the backup time setting means adds a time corresponding to the difference between the battery capacity and the total power consumption from a load unit having a high priority. The power supply control device according to claim 5.   The backup time setting means, when it is determined that the total power consumption exceeds the battery capacity, subtracts the time corresponding to the difference between the total power consumption and the battery capacity from the load unit having a low priority. The power supply control device according to claim 5.   The power supply control device according to claim 1, wherein the cumulative power consumption calculation unit calculates the cumulative power consumption from a load unit having a short backup time.   2. The power supply control device according to claim 1, wherein the end voltage specifying unit does not specify the end voltage of the load unit having the longest backup time among the plurality of load units. The battery is a secondary battery,
A main power source for supplying power from a commercial power source to each of the battery and the load unit;
Switching means for switching the power supply from the main power source to the battery according to the power supply state of the main power source,
The power supply control device according to claim 1, further comprising: A switch process for individually turning on / off the power supply from the battery to the plurality of load units;
A voltage monitoring step of monitoring each voltage applied to each load unit, and individually switching the switch means from an on state to an off state when the voltage reaches a predetermined power supply stop voltage;
Based on the priority order determined according to the importance of each load unit, a backup time setting step for preferentially setting the backup time from the load unit with a high priority,
Based on the current consumption of each load unit and the backup time, a cumulative power consumption calculation step for calculating the cumulative power consumption required until the backup time of each load unit expires,
Based on the battery characteristic information indicating the relationship between the discharge capacity of the battery, the discharge current, and the end voltage, the end voltage specifying step for specifying the end power corresponding to the cumulative power consumption and power consumption of each load unit; ,
An end voltage setting step for setting the end voltage specified for each load unit as a power supply stop voltage in the voltage monitoring step, and
Including a power supply control method. In an image forming apparatus that includes a main power source and an auxiliary power source composed of a secondary battery that can be charged and discharged by power from the main power source, and that prints print data,
A plurality of load units for printing the print data that operates by power supplied from the main power supply or auxiliary power supply;
Switching means for switching power supply to each load unit from the main power source to the auxiliary power source according to the power supply state of the main power source,
A plurality of switch means for individually controlling on / off of power feeding from the auxiliary power source to the load units;
A plurality of voltage monitoring means for individually monitoring the voltage applied to each load unit, and switching the switch means individually from an on state to an off state when the voltage reaches a predetermined power supply stop voltage;
Storage means for storing battery characteristic information indicating the relationship between the discharge capacity of the auxiliary power supply, the discharge current, and the end voltage;
A backup time setting means for preferentially setting a backup time from a load unit with a high priority based on a priority determined according to the importance of each load unit;
Based on the current consumption of each load unit and the backup time, the cumulative power consumption required until the backup time of each load unit expires is calculated, and the end voltage corresponding to the cumulative power consumption and current consumption of each load unit is calculated. End voltage specifying means for specifying from the battery characteristic information;
A stop voltage setting means for setting the stop voltage specified for each load section as the power supply stop voltage in the voltage monitoring means related to the load section;
An image forming apparatus comprising:

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