Patent Publication Number: US-10310440-B2

Title: Image forming apparatus and power supply method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 15/393,406, filed on Dec. 29, 2016, the entire contents of each of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein relate generally to an image forming apparatus and a power supply method. 
     BACKGROUND 
     In the related art, an image forming apparatus which is provided with a rechargeable battery and able to operate even when power supply thereto is stopped due to a power failure of the commercial, i.e., local public, power supply, is known. 
     However, where the image forming apparatus is configured to maintain all of its functionality in a usable state when a power failure or interruption occurs, the usable time of the image forming apparatus once a power failure has occurred is short because the battery can rapidly discharge all of its power to maintain all of the image forming apparatus&#39; functions. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an example of an image forming apparatus of an exemplary embodiment. 
         FIG. 2  is a diagram illustrating a configuration of a power supply control unit provided in the image forming apparatus. 
         FIG. 3  is a diagram illustrating functional units to which power is supplied by a first power supply unit. 
         FIG. 4  is a diagram illustrating functional units to which power is supplied by a second power supply unit. 
         FIG. 5  is a diagram illustrating functional units to which power is supplied by a third power supply unit. 
         FIG. 6  is a flowchart illustrating operations of the power supply control unit. 
         FIG. 7  is a flowchart illustrating other operations of the power supply control unit. 
         FIG. 8  is a flowchart illustrating details of control operations of power supply according to a battery capacity. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, an image forming apparatus having a plurality of functional units includes a power failure detection circuit configured to detect a power failure of an external power supply for the image forming apparatus, a rechargeable battery unit, and a control unit. 
     The control unit switches the power supply source of the image forming apparatus from the external power supply to the rechargeable battery unit, and selects one or more of the functional units to power through the rechargeable battery unit based on a remaining capacity of the rechargeable battery unit, when the power failure of the external power supply is detected. 
     In the following, an image forming apparatus and a power supply method of an exemplary embodiment is explained with reference to accompanying drawings.  FIG. 1  is a diagram illustrating a perspective exterior view of an image forming apparatus  100  of an exemplary embodiment. The image forming apparatus  100  is, for example, a multi-function machine. The image forming apparatus  100  includes a display  110 , a control panel  120 , a printer unit  130 , a sheet accommodation unit  140 , and an image reading unit  200 . The printer unit  130  of the image forming apparatus  100  may be an apparatus fixing a toner image, or an inkjet type apparatus. 
     The image forming apparatus  100  forms an image on a sheet using a recording agent such as toner. The sheet is, for example, paper or label paper. The sheet may be any type of sheet as long as the image forming apparatus  100  can form an image on the surface of the sheet. 
     The display  110  is an image display device such as a liquid crystal display, an organic electro luminescence (EL) display, or the like. The display  110  displays various information concerning the status and operation of the image forming apparatus  100 . 
     The control panel  120  includes a plurality of user selectable buttons. The control panel  120  receives a user&#39;s input requesting performance of one or more operations. The control panel  120  outputs a signal according to operations selected by the user to the control unit of the image forming apparatus  100 . The display  110  and the control panel  120  may be integrally configured as a touch panel. 
     The printer unit  130  forms an image on a sheet based on image information generated by the image reading unit  200  or image information received through a communication path to the image forming apparatus  100 . The printer unit  130  forms an image by, for example, using the following methodology: An image forming unit of the printer unit  130  forms an electrostatic latent image on a photoconductive drum based on image information. The image forming unit of the printer unit  130  causes a recording agent, for example toner, to attach to the electrostatic latent image to form a visible image thereby. A specific example of the recording agent includes toner. A transfer unit of the printer unit  130  transfers the visible image onto the sheet. A fixing unit of the printer unit  130  performs heating and pressing with respect to the sheet to fix the visible image on the sheet. 
     The sheet which is subjected to the image forming process by the printer unit  130  may be a sheet accommodated in the sheet accommodation unit  140  or a sheet manually supplied by the user. The sheet accommodation unit  140  accommodates the sheet used for forming an image by the printer unit  130 . 
     The image reading unit  200  reads information of an image being read based on the brightness and darkness of the image. The image reading unit  200  records the read image information. The recorded image information may be transmitted to another information processing apparatus through a network. The image of the recorded image information is formed on a sheet by the printer unit  130 . 
     A first battery  16  (rechargeable battery), a second battery  17 , and a third battery  18  are provided in the image forming apparatus  100 . The capacity (total possible charge or power) of the first battery  16  is the largest among three batteries. The capacity of the third battery  18  is the smallest among the three batteries. That is, the relationship of the battery capacity as between three batteries is that the capacity of the first battery is larger than the capacity of the second battery which is larger than the capacity of the third battery. A power supply control unit  1 , which controls power supply from the three batteries when a power failure of the commercial power supply occurs, is provided inside the image forming apparatus  100 . When a power failure occurs, operations of the image forming apparatus  100  are maintained by the batteries  16 ,  17  and  18  as controlled by the power supply control unit  1 . 
     Next, a configuration of the power supply control unit  1  provided inside the image forming apparatus  100  will be described with reference to  FIG. 2 .  FIG. 2  is a diagram illustrating a configuration of the power supply control unit  1  provided inside the image forming apparatus  100 . When the externally supplied power to the image forming apparatus  10  fails or is interrupted or a natural disaster occurs, the power supply control unit  1  controls supply of power by the rechargeable batteries  16 ,  17  and  18  provided inside the image forming apparatus  100  to one or more functional units of the image forming apparatus  100 . 
     The power supply control unit  1  includes a control unit  11 , which is a hardware controller implemented as an application specific integrated circuit (ASIC), field programmable gate array (FPGA), or a processor programmed with a control program, a reception unit  12 , an earthquake (or other natural disaster notification) detection unit  13  (hereinafter an earthquake detection unit), an AC power supply unit  14 , and a power failure detection unit  15 . In one embodiment, the reception unit  12  is implemented as a circuit, the earthquake detection unit is implemented as a circuit, the AC power supply unit is implemented as a circuit, and the power failure detection unit is implemented as a circuit. 
     The power supply control unit  1  includes a first battery  16 , a second battery  17 , and a third battery  18 . The power supply control unit  1  includes a first power supply unit  19 , a second power supply unit  20 , and a third power supply unit  21 . 
     The control unit  11  integrally controls operations of the power supply control unit  1 . The reception unit  12  receives an emergency earthquake (or other disaster) warning issued by a meteorological or other agency. The reception unit  12  may be equipped with an emergency earthquake (or other natural disaster event) warning receiving method capable of receiving a signal from a mobile phone base station, acquiring information through the Internet, or receiving a radio wave. The earthquake detection unit  13  includes an acceleration sensor, determines that an earthquake has occurred and outputs an earthquake detection result, when detected acceleration output by the acceleration sensor exceeds a predetermined value. The AC power supply unit  14  is connected to the commercial power supply and supplies power used for the operations performed by the image forming apparatus  100 . The power failure detection unit  15  detects occurrence of the power failure based on whether or not the supply of AC power has stopped. 
     The first battery  16  is configured as a rechargeable battery and supplies power to perform the functions of the image forming apparatus  100  as a result of a power supply instruction from the control unit  11 . The second battery  17  is configured as a rechargeable battery and supplies power to perform the functions of the image forming apparatus  100  as a result of a power supply instruction from the control unit  11 . The third battery  18  is configured as a rechargeable battery and supplies power to perform the functions of the image forming apparatus  100  as a result of a power supply instruction from the control unit  11 . When a power failure does not occur and the ac power supply  14  is supplying power from an external source to the image forming apparatus  100 , the first battery  16 , the second battery  17 , and the third battery  18  are charged by power supplied from the AC power supply unit  14 . The functions the functions of the image forming apparatus  100  which are maintained by the battery power are implemented by functional units provided in the image forming apparatus  100 . Specific examples of the functional units include an image forming unit, a reception unit, an image reading unit, and a FAX communication unit. The image forming unit is hardware installed with a function of forming an image on a sheet. The reception unit is hardware installed with a function of receiving information from an external device through a wired communication path or a wireless communication path. The image reading unit is hardware installed with a function of reading the image formed on the sheet. The FAX communication unit is hardware installed with a function of receiving a FAX signal from another apparatus. The functional units provided in the image forming apparatus  100  are not limited to the specific examples described above. Details of the functions maintained by the power of the respective batteries will be described later herein. 
     The image forming apparatus  100  includes three types of batteries including a large-capacity battery (first battery  16 ), a medium-capacity battery (second battery  17 ), and a small-capacity battery (third battery  18 ) in conformity with the layout and available volume therefor inside the image forming apparatus  100 . The reason that three batteries are provided is to maintain the function of the image forming apparatus  100  in a usable state using power of the other batteries when any one or two of the batteries fail or are depleted. 
     The first power supply unit  19  supplies power to respective functional units so that all functions equipped in the image forming apparatus  100  are in a usable state. The first power supply unit  19  supplies power using power stored in the first battery  16 , the second battery  17 , and the third battery  18 . The first power supply unit  19  supplies power to respective functional units so that all functions are in a usable state and thus, uses the first battery of which the capacity is the largest. 
       FIG. 3  is a diagram illustrating functional units to which power is supplied by a first power supply unit  19 . The first power supply unit  19  supplies power to a printing functional unit  31 , a scanning functional unit  32 , a FAX transmission and reception functional unit  33 , a communication functional unit  34 , and a user interface (UI) functional unit  35 . The printing functional unit  31  is a functional unit implementing a function for the printer unit  130  illustrated in  FIG. 1 . The scanning functional unit  32  is a functional unit implementing a function for the image reading unit  200  illustrated in  FIG. 1 . 
     The second power supply unit  20  supplies power to selected functional units so that functions except for a printing function, as among the functions equipped in the image forming apparatus  100 , are in a usable state. The second power supply unit  20  supplies power using power stored in the second battery  17 . The second power supply unit  20  supplies power to respective functional units so that all functions of the image forming apparatus except for the printing function are in a usable state and thus, uses a second battery of which the capacity is approximately a medium level. The functions except for the printing function include a user interface operation function, a scanning function, a FAX transmission and reception function, and a communication function (transmitting and receiving of mail or the like) are maintained by the second battery. The user interface operation function enables input operations and displaying using a display  110  and a control panel  120  illustrated in  FIG. 1 . During operation of the second power supply unit  20 , received FAXes and e-mails or other electronic documents received by the image forming apparatus cannot be printed but the contents or descriptors of the received FAXes, emails and other documents can be displayed on the display  110  such that the contents can be confirmed by the user. 
       FIG. 4  is a diagram illustrating functional units to which power is supplied by the second power supply unit  20 . The second power supply unit  20  supplies power from the second battery  17  and the third battery  18  to the scanning functional unit  32 , the FAX transmission and reception functional unit  33 , the communication functional unit  34 , and the UI functional unit  35 . 
     The third power supply unit  21  supplies power to respective functional units so that only the user interface operation and the communication function, as among the functions equipped in the image forming apparatus  100 , are in a usable state. The third power supply unit  21  supplies power using the power stored in the third battery  18 . The third power supply unit  21  supplies power to selected functional units so that only the user interface operation and the communication function are in a usable state and thus, uses the third battery of which the capacity is the smallest as among the three batteries  16 ,  17  and  18 . During operation of the third power supply unit  21 , received FAXes and e-mails or other electronic documents received by the image forming apparatus cannot be printed but the contents or descriptors of the received FAXes, emails and other documents can be displayed on the display  110  such that the contents can be confirmed by the user. 
       FIG. 5  is a diagram illustrating functional units to which power is supplied by the third power supply unit  21 . The third power supply unit  21  supplies power only to the communication functional unit  34  and the UI functional unit  35 . 
     Next, operations of the power supply control unit  1  illustrated in  FIG. 2  will be described with reference to  FIGS. 6 and 7 .  FIGS. 6 and 7  are flowcharts illustrating operations of the power supply control unit  1  illustrated in  FIG. 2 . The operations illustrated in  FIGS. 6 and 7  are repeatedly executed at predetermined time intervals. Power is always supplied to the power supply control unit  1  from any of the first battery, the second battery, and the third battery such that the power supply control unit  1  is able to operate even when a power failure occurs, so long as usable power remains in any of the three batteries  16 ,  17  and  18 . 
     First, the control unit  11  reads an output of the power failure detection unit  15  and determines whether a commercial power failure has occurred (ACT 1 ). As a result of this determination, when the power failure has not occurred (ACT 1 : NO), the control unit  11  ends processing. On the other hand, when a power failure occurs (ACT 1 : YES), the control unit  11  reads an output of the reception unit  12  and determines whether an emergency earthquake warning (or other warning) is detected (ACT 2 ). 
     As a result of the determination, when the emergency earthquake warning is detected (ACT 2 : YES), the control unit  11  reads an output of the earthquake detection unit  13  and determines whether an earthquake is detected (ACT 3 ). As a result of the determination, when the earthquake is detected (ACT 3 : YES), the control unit  11  starts battery-powered operation (ACT 4 ). When the battery-powered operation is started, the control unit  11  supplies power based on the capacities of the batteries  16 ,  17  and  18  (ACT 5 ). The control unit  11  reads the output of the power failure detection unit  15  and determines whether the commercial AC power supply is restored (ACT 6 ). As a result of this determination, that the commercial AC power supply is restored (ACT 6 : YES), the control unit  11  switches the power supply source to the AC power supply unit  14  and ends processing. In this case, the control unit  11  stops disabling image forming apparatus functions such that all functions become usable. On the other hand, when the commercial AC power supply is not restored (ACT 6 : NO), the control unit  11  reads the remaining capacity of the third battery  18  and determines whether battery power remains (ACT 7 ). The determination as to whether battery power remains to power the image forming apparatus is based on whether the voltage of the third battery  18  is less than or equal to a predetermined value. As battery power is consumed by the image forming apparatus  100  in the order of the first battery  16 , the second battery  17 , and the third battery  18 , if the third battery  18  does not have remaining capacity (remaining power), none of the batteries have remaining capacity (remaining power). 
     As a result of this determination, when there is remaining battery capacity (ACT 7 : YES), the control unit  11  returns to ACT 5  and repeats the processing. On the other hand, when there is no remaining battery capacity (ACT 7 : NO), the control unit  11  outputs a message to the display  110 . The message sent to the display  110  is, for example “Functions will stop soon.” The control unit  11  stops operating the image forming apparatus  100  (ACT 8 ) and the image forming apparatus  100  shuts down. 
     Next, operations when a power failure without the occurrence of a disaster such as an earthquake ( FIG. 7 ) will be described. When the emergency earthquake warning is not detected (ACT 2 : NO in  FIG. 6 ) and thus when an earthquake is not detected (ACT 3 : NO in  FIG. 6 ), the control unit  11  starts the battery-powered operation of the image forming apparatus  100  (ACT 9 ). 
     The control unit  11  issues an instruction to the first power supply unit  19  (ACT 10 ). The first power supply unit  19  receiving the instruction supplies power to all of the functional units of the image forming apparatus  100  using the power stored in the first battery  16 , the second battery  17 , and the third battery  18 . As such, even when the power failure occurs, all functions of the image forming apparatus  100  may be maintained in a usable state. 
     The control unit  11  reads an output of the power failure detection unit  15  and determines whether the commercial AC power supply has been restored (ACT 11 ). As a result of the determination, when the commercial AC power supply has been restored (ACT 11 : YES), the control unit  11  switches the power supply source to the commercial AC power supply unit  14  and ends processing. On the other hand, when the commercial AC power supply has not been restored (ACT 11 : NO), the control unit  11  reads the remaining capacity of the first battery  16 , the second battery  17 , and the third battery  18  and determines whether battery capacity remains to power the image forming apparatus  100  (ACT 12 ). The determination that insufficient battery capacity remains is based on whether voltages of the first battery  16 , the second battery  17 , and the third battery  18  are less than or equal to a predetermined value, i.e., they have been discharged below a threshold level. 
     As a result of the determination, when sufficient battery capacity remains in any one of the three batteries to power the image forming apparatus  100  (ACT 12 : YES), the control unit  11  returns to ACT 10  and continues the processing. On the other hand, when insufficient battery capacity remains (ACT 12 : NO), the control unit  11  outputs a message to the display  110 . The message to be output is, for example, “Functions will stop soon.” The control unit  11  then stops operating the image forming apparatus  100  (ACT 13 ), and the image forming apparatus  10  shuts down. 
     Next, details of control operations of power supply (ACT 5 ) based on the remaining battery capacity as illustrated in  FIG. 6  will be described with reference to  FIG. 8 .  FIG. 8  is a flowchart illustrating details of control operations (ACT 5 ) of power supplied to the image forming apparatus  100  based on the remaining battery capacity as illustrated in  FIG. 6 . 
     First, when control of power supplied using battery capacity is started, the control unit  11  detects the remaining capacity of the first battery  16  (ACT 51 ). The detected remaining battery capacity is based on the detected voltage value of the first battery  16 . 
     Next, the control unit  11  determines whether the remaining capacity of a first battery is sufficient to power the desired functions of the image forming apparatus  100  (ACT 52 ). As a result of this determination, when the remaining capacity of the first battery is sufficient (ACT 52 : YES), the control unit  11  issues an instruction to the first power supply unit  19  (ACT 53 ). 
     The first power supply unit  19  receiving this instruction supplies power to all of the functional units of the image forming apparatus  100  using the power stored in the first battery  16 . In this case, the control unit  11  outputs a message to the display  110 . The message to be output is, for example, “Being operated using battery.” Thus, even when a power failure occurs, all functions of the image forming apparatus  100  may be maintained in a usable state. 
     When the remaining capacity of the first battery is not sufficient, i.e., the first battery  16  is discharged below the threshold value and cannot power all of the functionality of the image forming apparatus  100  (ACT 52 : NO), the control unit  11  detects the remaining capacity of the second battery  17  (ACT 54 ). Subsequently, the control unit  11  determines whether the remaining capacity of the second battery is sufficient to power a preselected reduced number of desired functions of the image forming apparatus  100  (ACT 55 ). As a result of the determination, when the remaining capacity of the second battery is sufficient (ACT 55 : YES), the control unit  11  issues an instruction to the second power supply unit  20  (ACT 56 ). 
     The second power supply unit  20  receiving the instruction supplies power to the functional units of the image forming apparatus  100 , except the printing unit, using the power stored in the second battery  17 . In this case, the control unit  11  outputs a message to the display  110 . The message to be output is, for example, “Being operated using battery. Only scanner and communication functions such as, FAX transmission, displaying of receipt of email and electronic documents, and the like are usable. Printing is not allowed.” Thus, even when a power failure occurs, functions except for the printing function of the image forming apparatus  100  may be maintained in a usable state. 
     When the remaining capacity of the second battery is not sufficient to power the image forming apparatus  100  with the reduced functionality (ACT 55 : NO), the control unit  11  detects the remaining capacity of the third battery  18  (ACT 57 ). Subsequently, the control unit  11  determines whether the remaining capacity of the third battery is sufficient to power the image forming apparatus  100  with even further reduced functionality (ACT 58 ). As a result of the determination, when the remaining capacity of the third battery is sufficient to power the image forming apparatus  100  with even further reduced functionality (ACT 58 : YES), the control unit  11  issues an instruction to the third power supply unit  21  (ACT 59 ). 
     The third power supply unit  21  receiving the instruction supplies power to preselected functional units of the image forming apparatus  100  using power stored in the third battery such that only the user interface operation and the communication function of the image forming apparatus  100  are in a usable state. In this case, the control unit  11  outputs a message to the display  110 . The message to be output is, for example, “Being operated using battery. Only communication functions such as email are usable.” With this, even when a power failure occurs, the user interface operation and the communication function are in a usable state. On the other hand, when the remaining capacity of the third battery is not sufficient to power the image forming apparatus  100  with even further reduced functionality, a message stating that the image forming apparatus will shut down soon is displayed. Then, the control unit  11  ends the processing and the image forming apparatus shuts down. 
     Although an example of a configuration of an image forming apparatus in which three batteries are provided is described in the above-description, a configuration in which only a single battery is provided may be adopted. Also, in this case, the functions of the image forming apparatus  100  receiving power from battery power are selected based on the remaining battery capacity, and thus some usable functions are disabled. 
     Although an example of a configuration in which three batteries of which capacities are different from each other are provided is described, if space inside the image forming apparatus  100  is available, the size, and thus the capacity, of three batteries may be the same. 
     As having been described above, operable functions are restricted according to a remaining capacity of the battery and thus, operable time of the image forming apparatus  100  during a power failure may be extended. In particular, functions may be restricted based on the assumption that the duration of the power failure accompanied by a disaster is long, resulting in an extended usable time of the image forming apparatus under battery powered operation. When a power failure occurs which is not accompanied by a disaster, all functions are initially maintained in a usable state using the power stored in all of the batteries without restricting functions and thus, usability of the image forming apparatus under battery power may be improved. 
     While certain embodiments have been described these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms: furthermore various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.