Patent Publication Number: US-9417580-B2

Title: Image forming apparatus, control method thereof, and storage medium

Description:
BACKGROUND 
     1. Field 
     Aspects of the present invention generally relate to an image forming apparatus, a control method thereof, and a storage medium. 
     2. Description of the Related Art 
     Recently, an image forming apparatus maintaining power saving has a configuration in which power is not supplied to an engine, such as a printer and/or a scanner, while being in a sleep state. With this configuration, when performing a job, the image forming apparatus only activates an engine required for performing the job. 
     In addition, when a sheet jam occurs or consumables, such as sheets or toner, run out, in order to recover from such a state, a conventional image forming apparatus displays a maintenance screen on an operation unit. Information required for displaying the maintenance screen is often acquired from an engine, such as a printer and/or a scanner. 
     Japanese Patent Application Laid-Open No. 2002-300329 discusses a technique for turning off power source of a power source system by determining whether an image forming apparatus having a low power mode as a system is allowed to shift to the low power mode at a low power mode shifting time, and for performing sleep and recovery processing using a real-time clock (RTC). According to the technique discussed in Japanese Patent Application Laid-Open No. 2002-300329, in a case where an error is detected when shifting to the low power mode, the image forming apparatus shifts to the sleep mode after resolving the error. The error is referred to any state requiring maintenance, such as a sheet jam. 
     However, if the above conventional image forming apparatus shifts to the sleep mode with a sheet jam or without consumables, such as sheets or toner, since no power is supplied to an engine when the image forming apparatus is activated next time, a user notices the error, such as the sheet jam or the absence of the consumables only after the user actually causes the image forming apparatus to perform a job. Thus, not only the usability is deteriorated but also necessary maintenance is delayed. 
     In addition, according to the technique discussed in Japanese Patent Application Laid-Open No. 2002-300329, since the image forming apparatus shifts to the low power mode after resolving the error, power saving of when the error occurs is far from realized in the first place. As described above, no conventional techniques can achieve power saving without deteriorating the usability and the maintainability. 
     SUMMARY 
     Aspects of the present invention are generally directed to a configuration that can achieve power saving without deteriorating usability and maintainability of an image forming apparatus. 
     According to an aspect of the present invention, an image forming apparatus which has a plurality of units, power supply to each of the plurality of units being independently controllable, supplies power to each of the plurality of units when each of the plurality of units is used, the image forming apparatus comprising, a storage unit, being nonvolatile, configured to store, when a maintenance required state occurs, a maintenance required factor of the maintenance required state, a shifting unit configured to shift the image forming apparatus in the maintenance required state to a power saving state, a power supply unit configured to supply, when the image forming apparatus recovers from the power saving state, power to a unit corresponding to the maintenance required factor stored in the storage unit, an acquisition unit configured to acquire information about the maintenance required factor from the unit supplied with power by the power supply unit, and a display unit configured to display a maintenance screen based on the information acquired by the acquisition unit. 
     Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram illustrating a configuration of an image forming apparatus according to an exemplary embodiment. 
         FIG. 2  is a diagram illustrating an example configuration of an operation unit of the image forming apparatus. 
         FIG. 3  is a diagram illustrating an example maintenance screen displayed on the operation unit of the image forming apparatus. 
         FIG. 4  is a diagram illustrating an example of time charts of the image forming apparatus. 
         FIGS. 5A and 5B  are flowcharts each illustrating an operation of the image forming apparatus. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     Various exemplary embodiments, features, and aspects will be described in detail below with reference to the drawings. 
       FIG. 1  is a block diagram illustrating an example configuration of an image forming apparatus  1  according to an exemplary embodiment. The image forming apparatus  1  includes a scanner  2 , a printer  4 , an image processing unit  5 , a power supply device  6 , an operation unit  8 , a local area network (LAN) interface (I/F)  9 , and a controller  3 . 
     The scanner  2  is a scanner unit, which is an engine that optically reads an image from a document and converts the image into a digital image. The scanner  2  includes a document feed (DF) unit  11  capable of automatically and sequentially switching a stack of documents and a scanner unit  12  capable of optically scanning a document and converting the scanned document into a digital image. The scanner  2  transmits the converted image data to the controller  3 . 
     The printer  4  is a printer unit, which is an engine that outputs a digital image to a recording medium such as paper. The printer  4  includes a sheet feed unit  18  capable of sequentially feeding sheets one by one from a stack of sheets, a marking unit  16  for printing image data on the fed sheet, and a sheet discharge unit  17  for discharging the printed sheet. 
     The image processing unit  5  performs processing, such as reduction processing, on image data. The image processing unit  5  includes a general-purpose image processing unit  19  for performing image processing on image data. 
     The power supply device  6  is a device that supplies power in the image forming apparatus  1 . The operation unit  8  is a user interface for operations and displaying for the image forming apparatus  1 . The LAN I/F is for connecting the image forming apparatus  1  to a network. 
     The controller  3  is connected to the scanner  2 , the printer  4 , the image processing unit  5 , the power supply device  6 , the operation unit  8 , and the LAN I/F  9 . By issuing instructions to each of the modules, the controller  3  controls the entire image forming apparatus  1  and executes a job on the image forming apparatus  1 . The controller  3  includes a central processing unit (CPU)  13 , a hard disk drive (HDD)  14 , a memory  15 , a static random access memory (SRAM)  32 , and a chipset  33 . 
     By reading and executing a computer-readable program recorded in the HDD  14 , the CPU  13  realizes various control operations described below. The CPU  13  transmits/receives image data to/from the scanner  2  and the printer  4  and stores the image data. More specifically, the CPU  13  temporality stores image data received from the scanner  2  in the memory  15  and then stores the image data in the HDD  14 , so that scanning and storing of an image is completed. Further, the CUP  13  temporarily stores image data read from the HDD  14  in the memory  15  and transmits the image data from the memory  15  to the printer  4 , so that print output can be performed. Furthermore, the CPU  13  can causes the general-purpose image processing unit  19  to, for example, reduce image data stored in the memory  15  and can store the reduced image data in the memory  15  again. 
     The memory  15  includes a read-only memory (ROM) and a random access memory (RAM) that are not illustrated. The ROM stores a program and the like of the CPU  13 . The RAM is used as a work area of the CPU  13 . The HDD  14  stores digital images, control programs and the like. The SRAM  32  is a nonvolatile memory that stores various setting values of the image forming apparatus  1 . 
     The CPU  13  interprets an operation input by an operator via the operation unit  8 . In addition, the CPU  13  displays a job state and a state of an engine, such as the scanner  2  and/or the printer  4 , on a liquid crystal display (LCD) touch panel  600  (illustrated in  FIG. 2 ) of the operation unit  8 . In addition, the CPU  13  can input/output a digital image from a computer  10  via the LAN I/F  9  through a network  7 . The CPU  13  can also receive an instruction for issuance of job and an instruction of a device, and can perform processing therefore. In such a way, the CPU  13  can interpret instructions from the operation unit  8  and the LAN I/F  9  and perform various jobs. 
     The power supply device  6  is a device that supplies power in the image forming apparatus  1 . When the power of the image forming apparatus  1  is off, an alternating-current (AC) power supply  29  is insulated by a switch  30 . When the switch  30  is turned on, AC power is supplied to an AC-direct current (DC) converter  20 , and DC power is then generated. The power supply device  6  can independently supply power to the scanner  2 , the controller  3 , the printer  4 , and the image processing unit  5 . 
     The chipset  33  is a plurality of a series of related integrated circuits. The chipset  33  includes a real-time clock (RTC)  34 , which is a dedicated chip for measuring time. Since the RTC  34  receives power supply from an internal battery (not illustrated), the RTC  34  can operate even when no power is supplied to the controller  3  (for example, even when in the sleep state described below). As long as power is supplied to the chipset  33  in such a way, the image forming apparatus  1  can recover from the sleep state. In contrast, when the image forming apparatus  1  is in a shutdown state in which no power is supplied to the chipset  33 , the RTC  34  cannot operate. 
     The image forming apparatus  1  is sectioned into four sections through the power supply control unit  35 , and the power supply device  6  can independently control power supply for the four sections. More specifically, the power supply control unit  35  can control on/off of power supply for controller section power  25  using a switch unit  21 . Similarly, the power supply control unit  35  can control on/off of power supply for printer section power  28 , scanner section power  26 , and general-purpose image processing section power  27  using switch units  22 ,  23 , and  24 , respectively. By using these switch units  21  to  24 , the power supply control unit  35  appropriately supplies power to a necessary section in the image forming apparatus  1 . The power supply control unit  35  is configured by a complex programmable logic device (CPLD), for example. 
     Various power states of the image forming apparatus  1  will be described. 
     Sleep State 
     The sleep state is a state in which the image forming apparatus  1  achieves power saving (power saving state). More power can be saved in the sleep state than in the standby state described below. 
     Peripheral devices of the CPU  13  are set in a general suspended state (ACPI-S3, for example), and the power supply control unit  35  and only a unit (a sleep state power  31 ) that can detect a job are supplied with power. In such a way, the apparatus as a whole can be set in a very-low power state. More specifically, the CPU  13  stores a state of the image forming apparatus  1  in the memory  15  and instructs the power supply control unit  35  to turn off the controller section power  25 , which includes the CPU  13  itself, using the switch unit  21 . While the CPU  13  stops operating in the sleep state, since the sleep state power  31  is turned on by the power supply control unit  35 , the operation unit  8  or the LAN I/F  9  can detect a sleep recovery factor. The sleep state power  31  is not necessarily supplied to entire of the operation unit  8  and the LAN I/F  9 . Alternatively, supply of the sleep state power  31  may be performed, so that the image forming apparatus  1  can detect a sleep recovery factor. For example, when a reception through the network  7  via the LAN I/F  9  or an operation on the operation unit  8  (for example, pressing of a power saving key  610 ) is performed, the power supply control unit  35  turns on the controller section power  25 . Then, the CPU  13  and the like wake up. The CPU  13  reads the state of the image forming apparatus  1  stored in the memory  15  from the memory  15 , performs resetting, and causes the image forming apparatus  1  to recover to the state immediately before the controller section power  25  is turned off. Then, the image forming apparatus  1  shifts to the standby state. The image forming apparatus  1  receives a job after shifting to the standby state. The RTC  34  continuously measures time even in the sleep state. Thus, if a recovery time is set before the image forming apparatus  1  shifts to the sleep state, at the recovery time the RTC  34  can wake the power supply control unit  35  to perform a sleep recovery operation and to wake the CPU  13 . 
     Standby State 
     The standby state is a state in which the controller section power  25  is supplied with power. In the standby state, the image forming apparatus  1  receives an operation from an operator via the operation unit  8  or a job through the network  7  via the LAN I/F  9 , for example. In the standby state, when not necessary, the printer section power  28 , the scanner section power  26 , and the general-purpose image processing section power  27  are off. Thus, as needed, the CPU  13  instructs the power supply control unit  35  to supply power to a device using a corresponding one of the switch units  22  to  24 , and a predetermined job is then executed. For example, depending on a job type, the power supply control unit  35  turns on power supply for each device necessary for the job, as described below. More specifically, in the standby state, the CPU  13  controls power supply for each device so that power is supplied to each device to be used and no power is supplied to the other devices not to be used. 
     [Copy Function] 
     The scanner section power  26  and the printer section power  28  are turned on to activate the scanner  2  and the printer  4  to realize a copy function. 
     [Image Storage Function] 
     Only the scanner section power  26  is turned on, and the scanner  2  and the HDD  14  are activated to store read image data. 
     [Print Function] 
     Only the printer section power  28  is turned on to activate the printer  4  to print various image data. 
     After a job is completed, the power supplied to the operated device is turned off using the corresponding switch units  22  to  24 . In such a way, power can be supplied only to the necessary device when necessary. Thus, the power consumed in the standby state can be reduced. 
       FIG. 2  is a diagram illustrating a configuration example of the operation unit  8 . 
     The LCD touch panel  600  illustrated in  FIG. 2  displays settings for executing a job, a job state, and engine states, for example. Further, the user can perform various operations by touching various buttons and the like displayed on the LCD touch panel  600 . A start key  607  is for starting a copy operation. A stop key  608  is for stopping a currently executed copy job. When the power saving key  610  is pressed, the image forming apparatus  1  shifts to the sleep state. When the power saving key  610  is pressed again, the image forming apparatus  1  recovers from the sleep state. A light-emitting diode (LED)  616  indicates that a job is currently executed or an image is being stored in an image memory. An error LED  617  indicates that the image forming apparatus  1  is in a maintenance required state where a jam occurs or a door opens, for example. A power supply LED  618  indicates that the image forming apparatus  1  is in the standby state. 
       FIG. 3  is a diagram illustrating a maintenance screen example displayed by the operation unit  8  when a maintenance required state, such as a sheet jam, occurs. 
     According to the example illustrated in  FIG. 3 , a field  701  displays that a sheet jam has occurred. A point  702  is for visually easily notifying the user of where the sheet jam has occurred. A field  703  displays a message for requesting the user to respond to the sheet jam. A field  704  displays a job state. 
       FIG. 4  is a diagram illustrating an example of time charts  801 ,  802 , and  803  of the image forming apparatus  1 . The power states illustrated in the time charts  801  to  803  are realized when the CPU  13  gives instructions to the power supply control unit  35 . 
     According to  FIG. 4 , the time charts  801  to  803  represent the power states of the controller  3 , the printer  4 , and the scanner  2 , respectively. In each of the time chart  801  to  803 , the standby state and the sleep state are indicated. The initial state in each of the time charts  801  to  803  is a power-on state. The controller  3  is in the standby state, and the printer  4  and the scanner  2  are in the sleep state. 
     At a timing  811 , a user presses the start key  607  on the copy screen as illustrated in  FIG. 2 . The CPU  13  turns on the scanner section power  26  and the printer section power  28  to activate the scanner  2  and the printer  4 , respectively. At a timing  812 , the image forming apparatus  1  starts a copy operation. At the timing  812 , the scanner  2  and the printer  4  are in the standby state. 
     A timing  813  indicates a timing in which a maintenance required state, such as a sheet jam, occurs and is detected. In the case of the printer  4 , examples of the maintenance required state other than a sheet jam include absence of consumables, such as sheets, print agent, for example, toner or ink, or staples, and opening of a door. In the case of the scanner  2 , examples of the maintenance required state include a document jam and opening of the DF unit  11 . More specifically, the maintenance required state refers to any state in which the user cannot obtain a desired job result without performing maintenance, and the maintenance required state is not limited to the above examples. At the timing  813 , the CPU  13  stores the factor that has required maintenance in the SRAM  32 , which is a nonvolatile memory, illustrated in illustrated  FIG. 1 . For example, according to the present exemplary embodiment, the CPU  13  stores information indicating that a sheet jam has occurred in the printer  4 . At a timing  820 , the controller  3  instructs the LCD touch panel  600  of the operation unit  8  to display the maintenance screen as illustrated in  FIG. 3 . 
     A timing  814  indicates a timing of shifting to the sleep state. Examples of a trigger of shifting to the sleep state include a timing of when the user presses the power saving key  610  illustrated in  FIGS. 1 and 2  or a case where the RTC  34  calls a sleep shifting time that is set in advance. At the timing  814  of shifting to the sleep state, the controller  3 , the printer  4 , and the scanner  2  each shift to the sleep state. More specifically, the CPU  13  instructs the power supply control unit  35  to turn off each of the power  25  to  28  using the corresponding switch units  21  to  24 . The controller  3  then controls displaying of the maintenance screen displayed at the timing  820  to be ended. 
     A timing  815  indicates a timing of recovery from the sleep state. Examples of a trigger of recovery from the sleep state include a timing of when the user presses the power saving key  610  illustrated in  FIGS. 1 and 2 . At the timing  815 , the power supply control unit  35  turns on the controller section power  25 , so that the power is supplied to the controller  3  and the controller  3  is activated. When activated, the controller  3  reads the factor that has required maintenance from the SRAM  32  and determines which engine needs to be recovered. For example, since the printer  4  is the factor according to the present exemplary embodiment, the controller  3  issues an activation request to the printer  4 . More specifically, the CPU  13  instructs the power supply control unit  35  to turn on the printer section power  28  using the switch unit  22 , and the printer  4  is then activated. On the other hand, for example, since the scanner  2  is not the factor that has required maintenance, the scanner  2  is not recovered from the sleep state. 
     After the activation of the printer  4 , at a timing  822 , the controller  3  queries the printer  4  about the factor that has required maintenance. The printer  4  responds to the query by notifying the controller  3  of the factor that has required maintenance, for example, a sheet jam. The timing in which the controller  3  detects the notification is a timing  816  in which the maintenance required state is detected. From the timing  816 , the controller  3  controls the LCD touch panel  600  of the operation unit  8  to display the maintenance screen as illustrated in  FIG. 3 . 
     The maintenance screen continues to be displayed until the image forming apparatus  1  recovers from the maintenance required state, which is a timing  817 . Examples of operations for recovery from the maintenance required state include, in a case where the maintenance required state is due to a sheet jam, the user removes the sheet jam. In a case where the maintenance required state is due to absence of toner, the user replenishes toner. After recovering from the maintenance required state, the image forming apparatus  1  does not need to maintain the engines activated. Thus, with the recovering from the maintenance required state as a trigger, the controller  3  instructs the printer  4  to shift to the sleep state. The printer  4  then shifts to the sleep state. A timing  818  indicates that it is the timing for shifting to the sleep state, again. At the timing  818 , shifting to the sleep state is performed in the same way as the above described timing  814 . 
       FIG. 5  is a flowchart illustrating an operation of the image forming apparatus  1 . Each process illustrated in the flowchart is realized in such a manner that the CPU  13  executes a computer-readable program stored in the HDD  14 . 
     An operation of the controller  3  in a case where the image forming apparatus  1  becomes in the maintenance required state and shifting to the sleep state is performed will be described with reference to  FIG. 5A . 
       FIG. 5A  is a flowchart illustrating an operation example of the controller  3  in a case where the image forming apparatus  1  becomes in the maintenance required state and shifts to the sleep state. 
     In step S 101 , the CPU  13  monitors whether an event requiring maintenance occurs. In a case where the CPU  13  determines that there is no event requiring maintenance (NO in step S 101 ), the CPU  13  continues monitoring in step S 101 . However, in case where the CPU  13  determines that the event requiring maintenance occurs (YES in step S 101 ), the processing proceeds to step S 102 . Such an operation corresponds to the timing  813  according to the example illustrated in  FIG. 4 . 
     In step S 102 , the CPU  13  stores the factor that causes the maintenance required state, for example, the sheet jam in the printer  4  according to the present exemplary embodiment, in the SRAM  32  which is a nonvolatile memory illustrated in  FIG. 1 . 
     In step S 103 , as shown in the timing  820  illustrated in  FIG. 4 , the CPU  13  controls the LCD touch panel  600  of the operation unit  8  to display the maintenance screen as illustrated in  FIG. 3 . 
     In step S 104 , as shown in the timing  814  illustrated in  FIG. 4 , the CPU  13  forcibly performs shifting to the sleep state. Examples of a trigger of shifting to the sleep state include a timing of when the user presses the power saving key  610  illustrated in  FIGS. 1 and 2  or a case where the RTC  34  calls a sleep shifting time that is set in advance. At the timing  814  of shifting to the sleep state, the controller  3 , the printer  4 , and the scanner  2  each shift to the sleep state. 
     With reference to  FIG. 5B , an operation of the controller  3  in a case where the image forming apparatus  1  recovers from the sleep state will be described. 
       FIG. 5B  is a flowchart illustrating an operation of the controller  3  in a case where the image forming apparatus  1  recovers from the sleep state. 
     In step S 201 , in a case where the CPU  13  detects a sleep recovery factor (YES in step S 201 ), the power supply control unit  35  causes the controller section power  25  to turn on, and the controller  3  is supplied with the power. Then, in step S 202 , the controller  3  is activated. Such an operation becomes the timing  815  illustrated in  FIG. 4  of recovery from the sleep state. Examples of the recovery factor include a timing of when the user presses the power saving key  610  illustrated in  FIGS. 1 and 2 . 
     After the activation of the controller  3 , in step S 203 , the CPU  13  reads the factor that has required maintenance from the SRAM  32 . In step S 204 , the CPU  13  determines whether to recover an engine from the sleep state. In a case where the CPU  13  determines not to recover any engine from the sleep state (NO in step S 204 ), the operation proceeds to step S 212 . 
     On the other hand, in a case where the CPU  13  determines to recover an engine from the sleep state (YES in step S 204 ), the processing proceeds to step S 205 . In step S 205 , the CPU  13  transmits an activation request to the engine corresponding to the maintenance required factor read from the SRAM  32  in step S 203 . For example, according to the present exemplary embodiment, since the printer  4  is the factor, the CPU  13  transmits the activation request to the printer  4 . More specifically, the CPU  13  instructs the power supply control unit  35  to turn on the printer section power  28  using the switch unit  22  so as to perform control to activate the printer  4  by supplying power. On the other hand, for example, since the scanner  2  is not the maintenance required factor, the CPU  13  does not cause the scanner  2  to recover from the sleep state in this step. 
     In step S 206 , the CPU  13  queries the engine (the printer  4  according to the present exemplary embodiment) about the maintenance required factor. The engine (the printer  4 ) responds to the query by notifying the controller  3  of information about the maintenance required factor, for example, a sheet jam. In such a procedure, the controller  3  acquires information about a maintenance required factor from a unit corresponding to the maintenance required factor. 
     In step S 207 , the CPU  13  determines whether the maintenance screen needs to be displayed. In a case where the CPU  13  determines that the maintenance screen does not need to be displayed (NO in step S 207 ), the processing proceeds to step S 210 . In step S 210 , the CPU  13  clears the maintenance required factor from the SRAM  32  and the processing proceeds to step S 211 . In step S 211 , the CPU  13  shifts the engine (the printer  4  according to the present exemplary embodiment) to the sleep state. 
     In a case where the CPU  13  determines that the maintenance screen needs to be displayed (YES in step S 207 ), the processing proceeds to step S 208 . In step S 208 , the CPU  13  controls the LCD touch panel  600  of the operation unit  8  to display the maintenance screen as illustrated in  FIG. 3 . 
     In step S 209 , the CPU  13  determines whether the image forming apparatus  1  has recovered from the maintenance required state. In a case where the CPU  13  determines that the image forming apparatus  1  has not recovered from the maintenance required state (NO in step S 209 ), the CPU  13  waits until the image forming apparatus  1  recovers from the maintenance required state. In a case where the CPU  13  determines that the image forming apparatus  1  recovers from the maintenance required state (YES in step S 209 ), the processing proceeds to step S 210 . In step S 210 , the CPU  13  clears the maintenance required factor from the SRAM  32  and the processing proceeds to step S 211 . In step S 211 , the CPU  13  shifts the engine (the printer  4  according to the present exemplary embodiment) to the sleep state. More specifically, the CPU  13  instructs the power supply control unit  35  to turn off the printer section power  28  using the switch unit  22  so as to control the printer  4  to shift to the sleep state by blocking power supplied to the printer  4 . 
     In step S 212 , the CPU  13  determines whether a sleep factor occurs. In a case where the CPU  13  determines that a sleep factor does not occur (NO in step S 212 ), the CPU  13  waits until a sleep factor occurs. On the other hand, in a case where the CPU  13  determines that a sleep factor occurs (YES in step S 212 ), the processing proceeds to step S 213 . In step S 213 , the CPU  13  shifts the controller  3  to the sleep state. 
     For example at the timing  818  illustrated in  FIG. 4 , the CPU  13  shifts the controller  3  to the sleep state. Examples of a trigger of shifting to the sleep state include, as similar in step S 104  illustrated in  FIG. 5A , a timing of when the user presses the power saving key  610  illustrated in  FIGS. 1 and 2  or a case where the RTC  34  calls a sleep shifting time that is set in advance. 
     In step S 209 , in a case where a sleep factor occurs while the CPU  13  is waiting for the image forming apparatus  1  to recover from the maintenance required state, the CPU  13  forcibly performs shifting to the sleep state, as similar in step S 104  in  FIG. 5A . 
     As described above, according to the present exemplary embodiment, even in the maintenance required state, the image forming apparatus  1  is forcibly shifted to the sleep state, which is effective in terms of power saving. Further, even in a case where the image forming apparatus  1  in the maintenance required state is forcibly shifted to the sleep state, the maintenance required factor is managed, a necessary engine is activated according to the maintenance required factor after the image forming apparatus  1  recovers from the sleep state, and the maintenance required state is displayed by the operation unit  8 , which is therefore effective in usability and maintainability. Furthermore, since power is supplied to only a necessary engine, but not to any other unnecessary engines, the image forming apparatus  1  according to the present exemplary embodiment can achieve power saving while maintaining usability and maintainability (without deteriorating usability and maintainability), which is also beneficial. Accordingly, the image forming apparatus can achieve power saving, maintainability, usability at the same time. Therefore, the image forming apparatus  1  according to the present exemplary embodiment can achieve power saving together with prompt recovery in an ad hoc manner from a maintenance required state that occurs. 
     The configurations and contents of various data are not limited to the above description. Depending on the intended use or purpose, various configurations or contents may be used. 
     While an exemplary embodiment has thus been described, additional exemplary embodiments may be applied to a system including a plurality of devices or to an apparatus including a single device. In addition, any of the above exemplary embodiments may arbitrarily be combined. 
     According to the present exemplary embodiment, the image forming apparatus can achieve power saving without deteriorating the usability and the maintainability. 
     Additional embodiments can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions recorded on a storage medium (e.g., computer-readable storage medium) to perform the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more of a central processing unit (CPU), micro processing unit (MPU), or other circuitry, and may include a network of separate computers or separate computer processors. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like. 
     While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that these exemplary embodiments are not seen to be limiting. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions. 
     This application claims the benefit of Japanese Patent Application No. 2013-259998 filed Dec. 17, 2013, which is hereby incorporated by reference herein in its entirety.