Electronic device, image forming apparatus, and control method for electronic device

Abstract

To reduce the time required for detecting whether a return factor occurring in an energy saving mode is caused by chattering, thereby reducing the time required for returning from the energy saving mode.SOLUTION: In an electronic apparatus, a main controller controls an apparatus body, and at the start-up based on detection, by a sensor, of a return factor from an energy saving mode, the main controller determines the time until the next restart to be a second time shorter than a first time according to the return factor, when the return factor is detected to have occurred due to chattering after the next restart, determines the time until the restart to be the first time, and when chattering is not detected, executes return processing on the apparatus body. A sub controller restarts the main controller on the basis of the occurrence of the return factor, stops the main controller when notified of the first time or the second time, and restarts the main controller after the lapse of the notified first time or second time.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an electronic device, an image forming apparatus, and a method for controlling an electronic device.

Background Art

[0002] A system such as an image processing apparatus including a main controller that controls the operation of a device body and a sub-controller that controls the startup and stop of the main controller is known. In this type of system, when the operation of the main controller is unnecessary, the sub-controller stops the main controller and shifts to an energy-saving mode.

[0003] During the energy-saving mode, the sub-controller temporarily activates the main controller at a predetermined cycle to return from the energy-saving mode to a standby mode or the like and updates the system clock. When the sub-controller detects a return factor such as network communication or a touch on an operation panel during the energy-saving mode, the sub-controller activates the main controller to return from the energy-saving mode and causes the main controller to perform processing according to the return factor.

[0004] The sub-controller suppresses an increase in power consumption during the energy-saving mode by adjusting the activation cycle of the main controller so that the time during which the main controller is activated per predetermined time is equal to or less than a target time. For example, when the sub-controller detects the occurrence of a return factor, the sub-controller extends the update cycle of the system clock or skips the activation of the main controller when a return factor with a low priority occurs (see, for example, Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, touch sensors on the control panel or sensors that detect the placement of documents in the automatic document feeder may experience chattering. To prevent the subcontroller from returning from energy-saving mode when chattering occurs, the subcontroller causes the main controller to reacquire sensor values ​​and detect the presence or absence of chattering during the next startup after the main controller has been started due to the occurrence of a cause for return. If the main controller detects chattering, the subcontroller will maintain the energy-saving mode without returning from it.

[0006] However, if, for example, the system clock update interval is set to a long value, it takes time for the main controller to start up again, and it takes time to acquire sensor values ​​to detect chattering. As a result, there is a problem that it takes time for the system to recover from energy-saving mode after detecting the cause of the recovery.

[0007] In view of the above issues, the present invention aims to shorten the time it takes to return from energy-saving mode by shortening the time it takes to detect whether or not the recovery factor occurring during energy-saving mode is caused by chattering. [Means for solving the problem]

[0008] To solve the above technical problems, one embodiment of the present invention provides an electronic device comprising a main controller for controlling the device body and a subcontroller for controlling the startup and shutdown of the main controller, wherein the main controller, upon startup based on the detection by a sensor of the occurrence of a recovery factor that restores the device body from energy-saving mode, determines the time until the next restart of the main controller to be a second time shorter than a first time, according to the recovery factor, and when it is detected that the recovery factor occurred due to chattering at the time of the next restart, it determines the time until the restart to the first time, and after the next restart, when the recovery factor occurs due to chattering The subcontroller includes a chattering detection unit that detects whether or not chattering has occurred, a notification unit that notifies the subcontroller of the first or second time determined by the recovery control unit, and a device recovery unit that performs recovery processing of the device body if chattering is not detected by the chattering detection unit after the next restart, and the subcontroller includes a startup control unit that restarts the main controller based on the detection of the occurrence of the recovery factor by the sensor, stops the main controller when the notification unit notifies the first or second time, and restarts the main controller based on the elapsed time of the notified first or second time. Furthermore, the aforementioned first time is set to a few seconds to 10 seconds. It is characterized by the following. [Effects of the Invention]

[0009] By reducing the time required to detect whether a recovery event occurring during energy-saving mode is caused by chattering, the time it takes to recover from energy-saving mode can be shortened. [Brief explanation of the drawing]

[0010] [Figure 1] This is an overall configuration diagram showing an example of an image forming apparatus according to one embodiment of the present invention. [Figure 2] Figure 1 is a block diagram showing an overview of the hardware configuration of the main parts of the image forming apparatus. [Figure 3]Figure 2 is a functional block diagram showing the functional configuration of the main CPU and sub-CPU. [Figure 4] This figure shows an example of a chattering detection information table. [Figure 5] Figure 3 is a sequence diagram showing an example of recovery from power-saving mode by the main CPU and sub-CPU. [Figure 6] This is a sequence diagram showing the continuation of Figure 5. [Figure 7] This is a sequence diagram showing the continuation of Figure 6. [Figure 8] Figure 3 is a sequence diagram showing another example of recovery from power-saving mode by the main CPU and sub-CPU. [Figure 9] This is a sequence diagram showing the continuation of Figure 8. [Figure 10] Figure 1 is a timing diagram showing an example of the operation of the main CPU in the energy-saving mode of the image forming apparatus. [Figure 11] This timing diagram shows another example of the operation of the main CPU in the energy-saving mode of the image forming apparatus shown in Figure 1. [Figure 12] This timing diagram shows yet another example of the operation of the main CPU in the energy-saving mode of the image forming apparatus shown in Figure 1. [Figure 13] This timing diagram shows an example of a malfunction in the main CPU operation of another image forming apparatus in energy-saving mode. [Modes for carrying out the invention]

[0011] Embodiments will be described below with reference to the drawings. In the following, a digital multifunction device (image forming apparatus) will be described as an example of an electronic device. However, the present invention is applicable to image forming apparatuses having a single function such as a scanner, printer, or facsimile, or to electronic devices (systems) such as projectors or electronic whiteboards.

[0012] Figure 1 is an overall configuration diagram showing an example of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 1 shown in Figure 1 is a digital multifunction printer (MFP: Multi-Function Printer) having functions such as copying, printing, scanning, and facsimile. The image forming apparatus 1 can switch between operating modes that realize the copying, printing, scanning, and facsimile functions, respectively, using application switching keys on the operation unit of the image forming apparatus 1. When the copying function is selected, the image forming apparatus 1 enters copy mode; when the printing function is selected, it enters print mode; when the scanning function is selected, it enters scanner mode; and when the facsimile function is selected, it enters facsimile mode.

[0013] Furthermore, the image forming apparatus 1 switches its internal state to an operating mode (operating state), a standby mode (standby state), or an energy-saving mode (power-saving mode), depending on the state of its internal circuitry. Hereafter, the energy-saving mode will also be referred to as the energy-saving mode.

[0014] For example, the operating mode includes copy mode or print mode for printing images or text data onto paper media. Print mode includes the operation of printing received data onto paper media in facsimile mode. The operating mode also includes scanner mode for scanning documents or transmission / reception operations in facsimile mode. The state of the internal circuitry is switched by user operation of the control panel or control within the image forming apparatus 1.

[0015] For example, the image forming apparatus 1 includes an automatic document feeder 2 (ADF: Auto Document Feeder), an image reading apparatus 3, a writing unit 4, a printer unit 5, an operation panel 11, a control device 12, and a power supply device 13. The printer unit 5 includes a photosensitive drum 6, a developing device 7, a conveyance belt 8, a fixing device 9, and a storage space for housing a paper feed tray 10. The automatic document feeder 2, the image reading apparatus 3, the writing unit 4, the printer unit 5, and the operation panel 11 are an example of a device main body for forming an image.

[0016] The printer unit 5 creates a toner image to be transferred onto a paper medium or the like based on image information. The printer unit 5 is an example of an image forming unit for forming an image. Hereinafter, as an example of the flow of image formation in the image forming apparatus 1, the case where the operation mode is set to the copy mode will be briefly described.

[0017] In the copy mode, a plurality of original documents to be copied are set on the automatic document feeder 2, or an original document to be copied is set on the image reading apparatus 3. When the start button displayed on the operation panel 11 is pressed, the automatic document feeder 2 feeds the original documents one by one to the image reading apparatus 3. The image reading apparatus 3 reads the image information of each of the original documents sequentially sent from the automatic document feeder 2 or the original document set on the image reading apparatus 3. The image information read by the image reading apparatus 3 is processed by, for example, an image processing unit mounted on the control device 12.

[0018] The writing unit 4 converts the image information processed by the image processing unit into optical information. The photoreceptor drum 6 is uniformly charged by a charger positioned opposite the photoreceptor drum 6, and then exposed to laser light containing the optical information converted by the writing unit 4. Exposure forms an electrostatic latent image on the photoreceptor drum 6. The developing unit 7 develops the electrostatic latent image on the photoreceptor drum 6 and forms a toner image on the photoreceptor drum 6. The transport belt 8 transfers the toner image to paper or the like. The fixing unit 9 fixes the toner image to the paper or the like. The transfer paper with the copied image of the original is then discharged from the discharge unit.

[0019] For example, the standby mode described above is the state in copy mode until the start button is pressed, while the operating mode is the state from when the start button is pressed until the paper medium is ejected, and the motor and other loads are operating. After the operating mode ends, the state of the image forming apparatus 1 returns to standby mode, and if the standby mode continues for a predetermined time, it enters energy-saving mode. Then, if the operation panel 11 is operated during energy-saving mode, the state of the image forming apparatus 1 returns to standby mode.

[0020] The control panel 11 accepts various inputs in response to user operations and displays various information on its display unit. For example, the information displayed on the control panel 11 may include information indicating the operation that was input, information indicating the operating status of the image forming apparatus 1, or information indicating the settings status of the image forming apparatus 1.

[0021] The control device 12 controls the overall operation of the image forming apparatus 1, including the control of the printer unit 5, communication control, and input control to the operation panel 11, by having a control program executed by a built-in CPU or other controller. The control device 12 then performs image processing or data processing by executing an image processing program or data processing program to form an image to be transferred to paper media or the like.

[0022] The power supply unit 13 converts the AC voltage supplied from an AC power source such as a commercial power supply into several types of DC voltages (for example, a first DC voltage and a second DC voltage). The power supply unit 13 supplies the converted first DC voltage to various loads of the image forming apparatus 1, such as the printer unit 5. Examples of loads include various motors, a charger for charging the photoreceptor drum 6, and the developing rollers of the developing apparatus 7. The power supply unit 13 supplies the converted second DC voltage to the control device 12 as the operating power for the CPU (Central Processing Unit) and memory mounted in the control device 12.

[0023] Figure 2 is a block diagram illustrating the hardware configuration of the main components of the image forming apparatus 1 shown in Figure 1. The image forming apparatus 1 includes a main CPU 20, a sub-CPU 30, DRAM (Dynamic Random Access Memory) 40, SRAM (Random Access Memory) 50, and a sensor 60.

[0024] The main CPU 20 is an example of a main controller. The sub-CPU 30 is an example of a sub-controller that controls the startup and shutdown of the main CPU 20. In addition to what is shown in Figure 2, the image forming apparatus 1 may also have ROM (Read Only Memory), HDD (Hard Disk Drive), USB (Universal Serial Bus) interface, network interface, etc.

[0025] The main CPU 20 is mounted, for example, in the control device 12 shown in Figure 1. The main CPU 20 controls the overall operation of the image forming apparatus 1, including scanner operation, printer operation, and copy operation, by executing a control program stored in the DRAM 40. Furthermore, when transitioning to energy-saving mode, the main CPU 20 stores a snapshot of the control program in the SRAM 50 and stops operation. For example, the snapshot is data of the boot program as it is loaded into the DRAM 40.

[0026] The energy-saving mode is a low-power mode that reduces the power consumption of the image forming apparatus 1. Hereafter, the energy-saving mode will also be referred to as the energy-saving mode. When the main CPU 20 is stopped, the information held in the DRAM 40 is retained by a self-refresh operation.

[0027] The sub-CPU 30 is located near the image scanning device 3, for example, together with the operation panel 11 shown in Figure 1. The sub-CPU 30 controls the power on and off of the main CPU 20 based on the occurrence of recovery factors such as timer interrupts, operation of the operation panel 11, opening and closing of the cover of the automatic document feeder 2, or setting of a document in the image scanning device 3.

[0028] The sub-CPU 30 controls the transition to and recovery from energy-saving mode of the image forming apparatus 1 by controlling the power-on and power-off of the main CPU 20. Hereinafter, power-on of the main CPU 20 will also be referred to as starting up the main CPU 20, and power-off of the main CPU 20 will also be referred to as stopping the main CPU 20.

[0029] The energy-saving mode is activated, for example, when the operation panel 11 is not performed for a predetermined period of time. When switching to energy-saving mode, the sub-CPU 30 stores a snapshot of the operation program from the main CPU 20 to the SRAM 50, and then stops the main CPU 20. The sub-CPU 30 starts the main CPU 20 based on a timer interrupt or detection of an activation trigger during the energy-saving mode, and returns the image forming apparatus 1 from energy-saving mode to standby mode.

[0030] DRAM 40 holds the control program executed by the main CPU 20 and data used by the main CPU 20. SRAM 50 holds a snapshot of the control program and data used by the sub-CPU 30. Note that other RAM may be used instead of DRAM 40. Also, non-volatile memory such as flash memory or eMMC (embedded Multi Media Card), which allows for electrical data rewriting, may be used instead of SRAM 50.

[0031] The sensor 60 is, for example, an open / close sensor that detects the opening and closing of the cover of the automatic document feeder 2, or a document sensor that detects the placement of a document in the image scanning device 3. The sensor 60 may also be built into the operation panel 11 to detect touches on the operation panel 11. For example, the sensor 60 is used to detect a recovery factor that causes the system to return from energy-saving mode to standby mode.

[0032] Figure 3 is a functional block diagram showing the functional configuration of the main CPU 20 and sub-CPU 30 in Figure 2. Figure 3 also shows a functional block related to the control of returning from energy-saving mode to standby mode. The functional blocks shown in Figure 3 are implemented, for example, by control programs executed by the main CPU 20 and sub-CPU 30, respectively.

[0033] The main CPU 20 includes a system recovery unit 21, a recovery factor processing unit 22, a chattering detection unit 23, an energy saving management unit 24, and a sub-CPU notification unit 25. The sub-CPU 30 includes a recovery factor detection unit 31, a main CPU control unit 32, and a mode determination unit 33. Chattering detection information is stored in the DRAM 40 as a chattering detection information table 41.

[0034] The system recovery unit 21 performs control to return the image forming apparatus 1, which is an example of a system, from energy-saving mode to standby mode. Hereinafter, the image forming apparatus 1 will also be referred to as the system. The system recovery unit 21 is an example of an equipment recovery unit.

[0035] The recovery factor processing unit 22 refers to the chattering detection information table 41 when the main CPU 20 starts up based on the occurrence of a recovery factor. If the recovery factor is held in the chattering detection information table 41, the recovery factor processing unit 22 decides to perform chattering detection processing. If the recovery factor is not held in the chattering detection information table 41, the recovery factor processing unit 22 instructs the system recovery unit 21 to recover the main CPU 20 (system). The recovery factor processing unit 22 is an example of a recovery control unit.

[0036] The chattering detection unit 23 acquires sensor values ​​from the sensor 60 based on a chattering detection request from the recovery factor processing unit 22. The chattering detection unit 23 acquires the sensor value detection interval held in the chattering detection information table 41 corresponding to the recovery factor that occurred. The chattering detection unit 23 notifies the sub-CPU 30 of the chattering detection mode via the sub-CPU notification unit 25.

[0037] The energy saving management unit 24 requests the recovery factor processing unit 22 to perform recovery factor processing based on the occurrence of a recovery factor. The energy saving management unit 24 requests the system recovery unit 21 to recover the main CPU 20 (system) and notifies the sub-CPU 30 of the recovery of the main CPU 20 via the sub-CPU notification unit 25. The energy saving management unit 24 updates the system clock, such as the RTC (Real Time Clock).

[0038] The sub-CPU notification unit 25 notifies the sub-CPU 30 of various notification information received from the recovery factor processing unit 22, the chattering detection unit 23, and the energy saving management unit 24. For example, the sub-CPU notification unit 25 notifies the sub-CPU 30 of the main CPU startup / shutdown interval (the time interval from when the main CPU 20 stops until it starts up again), the chattering detection mode, the normal mode, or the recovery of the main CPU 20 (system). The sub-CPU notification unit 25 is just one example of a notification unit.

[0039] The recovery factor detection unit 31 of the sub-CPU 30 detects the occurrence of a recovery factor from energy-saving mode, such as detection by the sensor 60 or reception of data via the communication interface.

[0040] The main CPU control unit 32 controls the startup and shutdown of the main CPU 20. For example, the main CPU control unit 32 starts the main CPU based on a notification of the detection of a recovery factor from the recovery factor detection unit 31. In normal mode, after starting the main CPU 20, the main CPU control unit 32 stops the main CPU 20 after a preset time.

[0041] In chattering detection mode, the main CPU control unit 32 stops the main CPU 20 when the sub-CPU notification unit 25 notifies it of the main CPU start / stop interval, and starts the main CPU after the time indicated by the main CPU start / stop interval has elapsed. The main CPU control unit 32 is an example of a startup control unit.

[0042] The mode determination unit 33 determines whether the system is in normal mode or chattering detection mode based on the mode information notified by the sub-CPU notification unit 25. Normal mode is a mode in which the main CPU 20 is repeatedly started and stopped during power saving mode, and the stop time for the main CPU 20 is set in advance. Chattering detection mode is a mode in which chattering detection processing is performed after the main CPU 20 is started. In the initial state, when the mode determination unit 33 has not received mode information notification from the sub-CPU notification unit 25, it determines that the system is in normal mode.

[0043] The chattering detection information table 41 stores the recovery factors that trigger chattering detection, the main CPU startup / shutdown interval for each recovery factor, and the number of times the sensor value used for chattering detection has been detected. The chattering detection information table 41 is an example of a storage unit. An example of the chattering detection information table 41 is shown in Figure 4.

[0044] Figure 4 shows an example of the chattering detection information table 41 shown in Figure 3. The chattering detection information table 41 has multiple entries that hold the sensor value detection interval and the number of sensor value detections for each recovery factor among multiple recovery factors for which chattering detection is required. The sensor value detection interval is the detection interval for sensor values ​​obtained from sensor 60 to determine the presence or absence of chattering, and is used as the main CPU start-up / shutdown interval. The time shown for the sensor value detection interval for each recovery factor is an example of the second time. The number of sensor value detections is the number of times sensor values ​​are obtained from sensor 60 to determine the presence or absence of chattering, and is an example of the threshold number of detections for the occurrence of a recovery factor.

[0045] In the example shown in Figure 4, the recovery factors for detecting chattering include the opening and closing of the cover of the automatic document feeder 2, the setting of a document on the image scanning device 3, and detection by a human presence sensor. For example, the human presence sensor is attached to the image forming apparatus 1 and detects the approach of a person to the operation panel 11. The types of recovery factors for which chattering detection is required are not limited to the example shown in Figure 4, and may be one type or four or more types.

[0046] Note that the number of sensor value detections is used in the operations shown in Figures 8 and 9, but not in the operations shown in Figures 5 to 7. Therefore, if the operations shown in Figures 8 and 9 are not performed, the chattering detection information table 41 does not need to have a region for storing the number of sensor value detections.

[0047] Figures 5 to 7 are sequence diagrams showing an example of recovery from energy-saving mode by the main CPU 20 and sub-CPU 30 in Figure 3. In other words, Figures 5 to 7 show an example of the control method of the image forming apparatus 1. For example, Figures 5 to 7 are started when the sub-CPU 30 detects the occurrence of a recovery factor while the main CPU 20 is stopped in energy-saving mode. Hereafter, recovery from energy-saving mode to standby mode will also be referred to as recovery of the main CPU 20 system or system recovery.

[0048] First, the recovery factor detection unit 31 of the sub-CPU 30 detects the occurrence of a recovery factor that causes the system to return from energy-saving mode to standby mode, based on the detection by the sensor 60, and notifies the main CPU control unit 32 of the occurrence of the recovery factor along with information indicating the recovery factor (Figure 5(a)). Based on the notification of the recovery factor, the main CPU control unit 32 starts up the main CPU 20 (Figure 5(b)).

[0049] After the main CPU 20 starts up, the energy saving management unit 24 of the main CPU 20 requests the recovery factor processing unit 22 to perform processing according to the recovery factor (Figure 5(c)). The energy saving management unit 24 may update the system clock after the main CPU 20 starts up. The recovery factor processing unit 22 performs processing according to the recovery factor as shown below (Figure 5(d)). The recovery factor processing unit 22 refers to the chattering detection information table 41 (Figure 5(e)). The recovery factor processing unit 22 determines whether chattering detection processing is necessary based on whether the recovery factor detected by the recovery factor detection unit 31 is held in the chattering detection information table 41.

[0050] The recovery factor processing unit 22 determines that chatter detection is unnecessary if no recovery factor is stored in the chatter detection information table 41 (Figure 5(f)). In this case, the energy saving management unit 24 notifies the sub-CPU 30 of the recovery of the main CPU system via the sub-CPU notification unit 25 (Figure 5(g)). The energy saving management unit 24 also requests the system recovery unit 21 to recover the system (Figure 5(h)). Upon receiving the system recovery request, the system recovery unit 21 performs a system recovery process to return the image forming apparatus 1 from energy saving mode to standby mode (Figure 5(i)).

[0051] On the other hand, if the recovery factor is stored in the chattering detection information table 41, the recovery factor processing unit 22 determines that chattering detection is necessary and requests the chattering detection unit 23 to detect chattering (Figure 5(j)).

[0052] The chattering detection unit 23 acquires sensor values ​​from the sensor 60 corresponding to the location where the recovery factor occurs, based on the request for chattering detection (Figure 5(k)). The chattering detection unit 23 also refers to the chattering detection information table 41 and acquires the sensor value detection interval from the entry corresponding to the recovery factor detected by the recovery factor detection unit 31 (Figure 5(l)).

[0053] The chattering detection unit 23 notifies the sub-CPU 30 of the chattering detection mode, indicating that chattering has been detected, via the sub-CPU notification unit 25 (Figure 5(m)). The chattering detection mode information notified to the sub-CPU 30 is stored, for example, in the SRAM 50 or a register of the sub-CPU 30 that is accessible by the sub-CPU 30.

[0054] The recovery factor processing unit 22 notifies the sub-CPU 30 via the sub-CPU notification unit 25 that the sensor value detection interval obtained by the chattering detection unit 23 from the chattering detection information table 41 is the main CPU start-up / stop-down interval (Figure 5(n)).

[0055] Next, in Figure 6, when the main CPU control unit 32 of the sub-CPU 30 receives the main CPU start / stop interval from the main CPU 20, it stops the main CPU 20 (Figure 6(a)). Here, the main CPU start / stop interval is either the stop time of the main CPU 20 corresponding to the system clock update cycle in normal mode, or the sensor value detection interval in chattering detection mode received in Figure 5(n).

[0056] The stop time for the main CPU 20, which corresponds to the system clock update cycle in normal mode, is pre-set to a few seconds to about 10 seconds, and is an example of the first hour. The setting of the first hour is shorter the higher the system clock accuracy required by the system. Note that the second hour, which is the sensor value detection interval, is set to be shorter than the first hour.

[0057] The main CPU control unit 32 does not stop the main CPU 20 until it receives the main CPU start / stop interval from the main CPU 20. Therefore, for example, it is possible to prevent the main CPU 20 from being forcibly stopped by the sub-CPU 30 while the main CPU 20 is performing a chattering detection process. In other words, the main CPU control unit 32 can stop the main CPU 20 according to the processing load of the main CPU 20.

[0058] In contrast, if the main CPU control unit 32 stops the main CPU 20 after a timer has been set since the main CPU 20 was started, the main CPU 20 may be forcibly stopped while the chattering detection process is in progress.

[0059] The main CPU control unit 32 requests the mode determination unit 33 to determine the mode (Figure 6(b)). The mode determination unit 33 determines whether the mode is normal mode or chattering detection mode (Figure 6(c)).

[0060] For example, the mode determination unit 33 determines the normal mode if chattering detection mode information is not stored in the SRAM 50 or the registers of the sub-CPU 30, and determines the chattering detection mode if chattering detection mode information is stored. The mode determination unit 33 notifies the main CPU control unit 32 of the determined mode (Figure 6(d)). The main CPU control unit 32 starts the main CPU 20 after the main CPU start / stop interval has elapsed (Figure 6(e)).

[0061] In this embodiment, the main CPU startup and shutdown intervals differ between normal mode and chattering detection mode. This allows the main CPU 20 to be started up to detect chattering in a short time (first hour) after being stopped, even if, for example, the system clock update cycle (corresponding to the second hour) in normal energy-saving mode is set to be long. As a result, as will be described later, if chattering is not detected in chattering detection mode, the system can be quickly returned from energy-saving mode.

[0062] In normal mode, after the main CPU 20 starts up, the energy saving management unit 24 performs a system clock update process (Figure 6(f)). The main CPU 20 needs to obtain information on whether it is operating in normal mode or chatter detection mode after startup. For this reason, the sub-CPU 30 may notify the main CPU 20 whether it is operating in normal mode or chatter detection mode after the main CPU 20 starts up. Alternatively, the sub-CPU 30 may store information indicating whether it is operating in normal mode or chatter detection mode in a memory unit accessible from the main CPU 20.

[0063] Alternatively, the sub-CPU 30 may store whether it is in normal mode or chatter detection mode in a memory unit (e.g., DRAM 40) accessible from the main CPU 20, and the activated main CPU 20 may determine the mode by referring to the memory unit.

[0064] On the other hand, in chattering detection mode, after the main CPU 20 starts up, the energy saving management unit 24 first performs a system clock update process (Figure 6(g)). The energy saving management unit 24 requests the recovery factor processing unit 22 to perform processing according to the recovery factor (Figure 6(h)). The recovery factor processing unit 22 requests the chattering detection unit 23 to detect chattering (Figure 6(i)).

[0065] The chattering detection unit 23 acquires sensor values ​​from the sensor 60 corresponding to the location where the recovery factor occurs, based on the request for chattering detection (Figure 6(j)). The chattering detection unit 23 also refers to the chattering detection information table 41 and acquires the sensor value detection interval from the entry corresponding to the recovery factor detected by the recovery factor detection unit 31 (Figure 6(k)).

[0066] The chattering detection unit 23 then determines whether or not chattering has occurred based on the sensor value obtained from the sensor 60 (Figure 6(l)). For example, if the cause of the reset is that the cover of the automatic document feeder 2 has been opened, the chattering detection unit 23 detects the occurrence of chattering when the sensor value indicates that the cover of the automatic document feeder 2 is closed. The chattering detection unit 23 detects that chattering has not occurred when the sensor value indicates that the cover of the automatic document feeder 2 is open.

[0067] Next, in Figure 7, if the chattering detection unit 23 does not detect chattering, it determines that a recovery factor has occurred and notifies the energy saving management unit 24 of the occurrence of the recovery factor via the recovery factor processing unit 22 (Figure 7(a)). The energy saving management unit 24 notifies the sub-CPU 30 of the system recovery by the main CPU via the sub-CPU notification unit 25 (Figure 7(b)). The energy saving management unit 24 also issues a system recovery request to the system recovery unit 21 (Figure 7(c)).

[0068] On the other hand, if the chattering detection unit 23 detects chattering, it determines that no recovery factor has occurred and notifies the sub-CPU 30 of the normal mode via the sub-CPU notification unit 25 (Figure 7(d)). The recovery factor processing unit 22 notifies the sub-CPU 30 of the next main CPU startup / shutdown interval (first hour; for example, 10 seconds) via the sub-CPU notification unit 25 (Figure 7(e)).

[0069] In the sub-CPU 30, in normal mode, the main CPU control unit 32 stops the main CPU 20 again via the main CPU control unit 32 after a certain period of time has elapsed since the main CPU 20 was started (Figure 7(f)). In chattering detection mode, the main CPU control unit 32 stops the main CPU 20 again when it receives notification from the main CPU 20 regarding the next main CPU start-up / stop interval (Figure 7(g)).

[0070] Figures 8 and 9 are sequence diagrams showing another example of recovery from energy-saving mode by the main CPU 20 and sub-CPU 30 in Figure 3. That is, Figures 8 and 9 show an example of the control method for the image forming apparatus 1. The dashed box in Figure 8 represents the same process as shown in Figure 5, therefore the illustration and explanation of the process are omitted. Furthermore, detailed explanations of operations identical or similar to those in Figures 6 and 7 are omitted.

[0071] When the system is restored from energy-saving mode using the sequence shown in Figures 8 and 9, the number of sensor value detections is stored in the chattering detection information table 41 in Figure 4. The processing shown in Figures 8 and 9 differs from that in Figures 6 and 7 in that the main CPU 20 processes in chattering detection mode.

[0072] In the operation shown in Figures 8 and 9, the main CPU 20 needs to know how many times it has acquired sensor values ​​from the sensor 60 after the recovery factor has occurred. For this reason, when the sub-CPU 30 determines that the chattering detection mode is active, it notifies the main CPU 20 of the number of times the sensor values ​​have been acquired each time it starts up, or stores the number of times the sensor values ​​have been acquired in a memory unit accessible from the main CPU 20. For example, the sub-CPU 30 generates the number of times the sensor values ​​have been acquired by incrementing a count value that was reset to 0 when the chattering detection mode was determined by 1.

[0073] In Figure 8, the chattering detection unit 23 refers to the chattering detection information table 41 and obtains the sensor value detection interval and the number of sensor value detections from the entry corresponding to the recovery factor detected by the recovery factor detection unit 31 (Figure 8(a)). The chattering detection unit 23 then determines whether or not chattering has occurred (Figure 8(b)). The process shown in Figure 8 is the same as the process shown in Figure 6, except that the chattering detection unit 23 obtains the number of sensor value detections in addition to the sensor value detection interval.

[0074] In Figure 9, if the number of times sensor values ​​are acquired after the occurrence of a recovery factor is the same as the number of sensor value detections acquired from the chattering detection information table 41, the main CPU 20 performs the same processing as in Figure 7. That is, if the main CPU 20 determines that a recovery factor has occurred (no chattering detected), it notifies the sub-CPU 30 of the occurrence of the recovery factor and has the system recovery unit 21 restore the system (Figures 9(a), (b)). If the main CPU 20 determines that no recovery factor has occurred (chatering detected), it notifies the sub-CPU 30 of the normal mode and the next main CPU start / stop interval (first hour; for example, 10 seconds) (Figures 9(c), (d)).

[0075] On the other hand, if the number of times sensor values ​​have been acquired has not reached the number of sensor value detections obtained from the chattering detection information table 41, the chattering detection unit 23 notifies the sub-CPU 30 of the chattering detection mode via the sub-CPU notification unit 25 (Figure 9(e)). The recovery factor processing unit 22 also notifies the sub-CPU 30 of the next main CPU startup / shutdown interval (sensor value detection interval; for example, 1 second or 0.5 seconds) via the sub-CPU notification unit 25 (Figure 9(f)).

[0076] In Figure 9, the number of times sensor values ​​are acquired for chatter detection can be set for each recovery factor. For example, the number of sensor value detections for recovery factors that are prone to misidentifying chatter can be set to a value greater than the number of sensor value detections for recovery factors that are less prone to misidentifying chatter. This makes it possible to improve the accuracy of chatter detection while suppressing the increase in the time required for chatter detection.

[0077] Figure 10 is a timing diagram showing an example of the operation of the main CPU 20 in the energy-saving mode of the image forming apparatus 1 shown in Figure 1. In other words, Figure 10 shows an example of the control method of the image forming apparatus 1. The operation shown in Figure 10 corresponds to the processes shown in Figures 5 to 7. The main CPU startup and shutdown interval is set to 10 seconds in normal mode and to 1 second in chattering detection mode. In Figure 10, for example, a recovery trigger occurs when a document is detected being placed on the image reading device 3.

[0078] Figure 10(A) shows an example where chattering is detected. During power saving mode, the sub-CPU 30 restarts the main CPU 20 10 seconds after the main CPU 20 stops (Figures 10(a), (b)). The sub-CPU 30 starts the main CPU 20 based on the occurrence of a recovery factor while the main CPU 20 is stopped (Figure 10(c)).

[0079] The main CPU 20 determines that the recovery factor requires chatter detection (i.e., chatter detection mode) because the recovery factor is registered in the chatter detection information table 41 (Figure 10(d)). The main CPU 20 acquires sensor values ​​from the sensor 60 (Figure 10(e)). The main CPU 20 notifies the sub-CPU 30 of the sensor value detection interval (1 second) read from the chatter detection information table 41 in response to the recovery factor, as the next main CPU start-up / shut-down interval (Figure 10(f)).

[0080] The sub-CPU 30 stops the main CPU 20 based on the reception of the next main CPU start-stop interval (Figure 10(g)). The sub-CPU 30 restarts the main CPU 20 after the main CPU start-stop interval (1 second) (Figure 10(h)).

[0081] The chattering detection information table 41 shown in Figure 4 maintains a sensor value detection interval for each recovery factor. Therefore, the main CPU startup / shutdown interval when a recovery factor occurs can be set to an appropriate value for each recovery factor, separate from the main CPU startup / shutdown interval in normal mode (10 seconds).

[0082] The main CPU 20 updates the system clock, acquires sensor values, refers to the chattering detection information table 41, and determines chattering (Figure 10(i)). After restarting based on the detection of the recovery cause, the main CPU 20 restarts again at a shorter time than the main CPU start / stop interval in normal mode (10 seconds) to update the system clock. This suppresses a decrease in the accuracy of the system clock compared to, for example, performing the next restart at the main CPU start / stop interval in normal mode (10 seconds) after restarting based on the detection of the recovery cause.

[0083] The main CPU 20 determines that the cause of the recovery is due to chattering because the acquired sensor values ​​do not indicate a recovery from energy-saving mode (Figure 10(j)). Therefore, the main CPU 20 notifies the sub-CPU 30 that 10 seconds will be the next main CPU start / stop interval (Figure 10(k)). The sub-CPU 30 stops the main CPU 20 based on the reception of the next main CPU start / stop interval (10 seconds) (Figure 10(l)). The sub-CPU 30 restarts the main CPU 20 after 10 seconds (Figure 10(m)).

[0084] Figure 10(B) shows an example of the system recovering. The operation from the occurrence of a recovery event until the sub-CPU 30 starts the main CPU 20 after the main CPU start-up / stop interval (1 second) is the same as in Figure 10(A).

[0085] The main CPU 20 updates the system clock, acquires sensor values, refers to the chattering detection information table 41, and determines whether chattering has occurred (Figure 10(n)). The main CPU 20 determines that a recovery event has occurred (no chattering detected) because the acquired sensor value indicates a recovery from energy-saving mode (Figure 10(o)). Therefore, the main CPU 20 notifies the sub-CPU 30 that the system has recovered and recovers the system (Figure 10(p)).

[0086] Figure 11 is a timing diagram showing another example of the operation of the main CPU in the energy-saving mode of the image forming apparatus shown in Figure 1. In other words, Figure 11 shows an example of the control method of the image forming apparatus 1. The operation shown in Figure 11 corresponds to the processes shown in Figures 8 and 9. Detailed explanations of operations that are the same as or similar to those in Figure 10 are omitted. In Figure 11, the main CPU start-up / stop-down interval is set to 10 seconds in normal mode and to 0.5 seconds in chattering detection mode, as in Figure 10. In Figure 11, for example, a recovery trigger occurs due to the detection of a human presence by the motion sensor.

[0087] Figure 11(C) shows an example in which chattering is detected using the number of sensor value detections stored in the chattering detection information table 41. The operation from when a recovery factor occurs until the sub-CPU 30 starts the main CPU 20 after the main CPU start-up / shut-down interval is the same as in Figure 10(A), except that the CPU start-up / shut-down interval is 0.5 seconds.

[0088] The activated main CPU 20 updates the system clock and acquires sensor values. The main CPU 20 also acquires the sensor value detection interval and the number of sensor value detections from the entry in the chattering detection information table 41 corresponding to the recovery cause that occurred (Figure 11(a)).

[0089] The main CPU 20 determines that the number of sensor value acquisitions (1) has not reached the threshold of the number of sensor value detections (2) obtained from the chattering detection information table 41 (Figure 11(b)). In this case, the main CPU 20 notifies the sub-CPU 30 of the chattering detection mode and the next main CPU start / stop interval (0.5 seconds) (Figure 11(c)).

[0090] After stopping the main CPU 20, the sub-CPU 30 restarts the main CPU 20 after the main CPU startup / shutdown interval (0.5 seconds) (Figure 11(d)). The main CPU 20 updates the system clock and acquires sensor values. The main CPU 20 also acquires the sensor value detection interval and the number of sensor value detections from the entry in the chattering detection information table 41 corresponding to the recovery cause that occurred (Figure 11(e)).

[0091] The main CPU 20 performs a chattering detection and determines that the cause of the recovery is chattering because the acquired sensor value does not indicate a return from energy-saving mode. The main CPU 20 also determines that the number of times the sensor value has been acquired (2 times) has reached the threshold of the number of times the sensor value has been detected (2 times) obtained from the chattering detection information table 41 (Figure 11(f)). In this case, the main CPU 20 notifies the sub-CPU 30 of the normal mode and the next main CPU start-up / shut-down interval (10 seconds) (Figure 11(g)).

[0092] In Figure 11, the number of sensor value detections is set as a threshold in the chattering detection information table 41, and the main CPU 20 determines multiple times whether the recovery cause is due to chattering. In addition, in chattering detection mode, the main CPU start-up / shut-down interval is set to be shorter than the main CPU start-up / shut-down interval in normal mode.

[0093] This allows for multiple chatter detections to be performed in the shortest possible time while improving the accuracy of chatter detection. Furthermore, since the number of sensor value detections is set for each recovery factor that requires chatter detection, the appropriate number of sensor value detections can be set according to the characteristics of the sensor 60 that detects the recovery factor.

[0094] Figure 11(D) shows an example of the system being restored. The operation is the same as in Figure 11(C), in which the sub-CPU 30 stops the main CPU 20 based on the fact that the number of sensor value acquisitions (1) has not reached the number of sensor value detections (2), and then restarts after 0.5 seconds.

[0095] The main CPU 20 updates the system clock, acquires sensor values, refers to the chattering detection information table 41, and determines whether chattering has occurred (Figure 11(h)). The main CPU 20 determines that a recovery event has occurred (no chattering detected) because the acquired sensor value indicates a recovery from energy-saving mode (Figure 11(i)). Therefore, the main CPU 20 notifies the sub-CPU 30 that the system has recovered and recovers the system (Figure 11(j)).

[0096] Figure 12 is a timing diagram showing yet another example of the operation of the main CPU in the energy-saving mode of the image forming apparatus shown in Figure 1. In other words, Figure 12 shows an example of the control method of the image forming apparatus 1. The operation shown in Figure 12 indicates the occurrence of a recovery factor that does not require chattering detection. Detailed explanations of operations that are the same as or similar to those in Figure 10 are omitted.

[0097] Similar to Figure 10, the main CPU start / stop interval in normal mode is set to 10 seconds. In chatter detection mode, the main CPU start / stop interval is set to 1 second or 0.5 seconds. The operation from when a recovery factor occurs until the sub-CPU 30 starts the main CPU 20 is the same as in Figure 10(A).

[0098] The activated main CPU 20 refers to the chattering detection information table 41 and obtains sensor values ​​from the sensor 60 (Figure 10(a)). The main CPU 20 detects that there is no entry corresponding to the recovery factor in the chattering detection information table 41. In this case, the main CPU 20 notifies the sub-CPU 30 of the system recovery and restores the system (Figure 12(b)). In other words, if a recovery factor that does not require chattering detection occurs, the main CPU 20 can restore the system in the shortest possible time from the occurrence of the recovery factor without being stopped.

[0099] Figure 13 is a timing diagram showing an example of a malfunction in the main CPU operation in the energy-saving mode of another image forming apparatus. The image forming apparatus that performs the operation shown in Figure 13 does not have the chattering detection unit 23, mode determination unit 33, and chattering detection information table 41 shown in Figure 3, and operates only in normal mode. Detailed explanations of operations that are the same as or similar to those in Figure 10 are omitted.

[0100] In the image forming apparatus that performs the operation shown in Figure 13, the main CPU startup and shutdown interval is a preset fixed value (for example, 10 seconds or 5 seconds). Because the main CPU startup and shutdown interval is a fixed value, the main CPU does not notify the sub-CPU of the main CPU startup and shutdown interval.

[0101] If the main CPU startup / shutdown interval is set to a fixed value (e.g., 10 seconds) regardless of the recovery cause, as shown in Figure 13(F), it may take up to twice the fixed value for the main CPU to restart after it has stopped due to the occurrence of a recovery cause. This can delay system recovery if the recovery cause is not chattering. In addition, the system clock update cycle will be longer than the predetermined cycle, which may reduce the accuracy of the system clock.

[0102] Furthermore, if the main CPU does not notify the sub-CPU of the main CPU startup / shutdown interval, the sub-CPU will start the main CPU and then shut it down after a predetermined time period determined by a timer setting, etc. In this case, after the second restart of the main CPU following the occurrence of a recovery factor, the sub-CPU cannot determine whether the main CPU will perform the chattering detection process. In other words, the sub-CPU cannot determine whether it is in normal mode or chattering detection mode. Therefore, as shown in Figure 13(G), the sub-CPU may shut down the main CPU during the chattering detection process.

[0103] In this embodiment, even when the system clock update cycle is set to be long during normal energy-saving mode, the main CPU 20 can be started up in a short time after stopping in order to detect chattering. As a result, it is possible to quickly determine whether or not the cause of the recovery is due to chattering. Furthermore, if the cause of the recovery is not chattering, the system can be quickly restored from energy-saving mode.

[0104] The sub-CPU 30 will not stop the main CPU 20 until it receives the main CPU start / stop interval from the main CPU 20. Therefore, for example, if the main CPU 20 is performing a debouncing process, it is possible to prevent the main CPU 20 from being forcibly stopped by the sub-CPU 30.

[0105] The chattering detection information table 41 maintains a sensor value detection interval for each recovery factor. Therefore, the main CPU start / stop interval when a recovery factor occurs can be set to an appropriate value for each recovery factor, separate from the main CPU start / stop interval in normal mode.

[0106] After a restart based on the detection of a recovery cause, the main CPU 20 performs the next restart at a shorter time interval than the main CPU startup / shutdown interval in normal mode to update the system clock. This suppresses a decrease in the accuracy of the system clock compared to, for example, performing the next restart at the main CPU startup / shutdown interval in normal mode after a restart based on the detection of a recovery cause.

[0107] The chattering detection information table 41 maintains the sensor value detection interval for each recovery factor and maintains the number of sensor value detections as a threshold for each recovery factor. The main CPU 20 determines multiple times whether or not the recovery factor is due to chattering. This allows for multiple chattering determinations to be performed in the shortest possible time while improving the accuracy of chattering detection. Furthermore, since the number of sensor value detections is set for each recovery factor that requires chattering detection, an appropriate number of sensor value detections can be set according to the characteristics of the sensor 60 that detects the recovery factor.

[0108] Although the present invention has been described above based on various embodiments, the present invention is not limited to the requirements shown in the above embodiments. These points can be modified as long as they do not impair the spirit of the present invention, and can be appropriately determined according to their application. [Explanation of symbols]

[0109] 1. Image forming apparatus 2. Automatic document feeder 3. Image reading device 4 Writing Unit 5. Printer Unit 6. Photoconductor drum 7. Developing device 8. Conveyor belt 9 Fixing device 10 Paper feed tray 11. Control Panel 12 Control device 13 Power supply 20 Main CPU 21 System Recovery Section 22 Recovery Factor Processing Unit 23 Chattering detection unit 24 Energy Conservation Management Department 25 Sub-CPU notification unit 30 Sub-CPUs 31 Recovery Factor Detection Unit 32 Main CPU Control Unit 33 Mode determination unit 40 DRAM 41 Chattering Detection Information Table 50 SRAM 60 sensors AC alternating current power supply [Prior art documents] [Patent Documents]

[0110] [Patent Document 1] Japanese Patent Publication No. 2020-145664

Claims

1. The main controller controls the main unit of the device, The system includes a sub-controller that controls the startup and shutdown of the main controller, The aforementioned main controller A recovery control unit, which, upon startup based on the detection by a sensor of the occurrence of a recovery factor that restores the main unit from energy-saving mode, determines the time until the next restart of the main controller to be a second time shorter than the first time, according to the recovery factor, and when it is detected that the recovery factor occurred due to chattering during the next restart, determines the time until the restart to be the first time, A chattering detection unit detects whether the recovery factor occurred due to chattering after the subsequent restart, A notification unit that notifies the subcontroller of the first or second time determined by the recovery control unit, The device recovery unit performs a recovery process for the device body if no chattering is detected by the chattering detection unit after the aforementioned restart. The aforementioned subcontroller is A startup control unit restarts the main controller based on the detection of the occurrence of the recovery factor by the sensor, stops the main controller when the notification unit notifies the first or second time, and restarts the main controller based on the elapsed time of the notified first or second time, It has, The aforementioned first time is set to a few seconds to 10 seconds. Electronic devices characterized by the following:

2. The holding unit holds the second time corresponding to the recovery factor among the multiple recovery factors for which chattering detection is required, The return control unit, If the holding unit holds the second time in response to the recovery factor detected by the sensor, the time until the next restart is determined to be the second time. If the holding unit is not holding the second time in response to the recovery factor detected by the sensor, the device recovery unit is instructed to perform the recovery process. The electronic device according to claim 1, characterized by the following:

3. The sub-controller restarts the main controller one hour after stopping the main controller during the energy-saving mode. If the recovery control unit does not detect the occurrence of the recovery factor, it determines the time until the next restart of the main controller as the first time. The main controller updates the system clock used by the device when starting up after the first hour has elapsed since stopping, and when starting up based on the occurrence of the recovery factor. The electronic device according to claim 2, characterized by the above.

4. The holding unit maintains a threshold number of times the sensor detects the occurrence of the recovery factor, along with the second time, corresponding to the recovery factor. The return control unit, If the number of times sensor values ​​are acquired from the sensor after the next restart is less than the threshold value held in the holding unit corresponding to the recovery factor, the second time held in the holding unit corresponding to the recovery factor is determined to be the time until the restart. If the number of times the sensor value is acquired from the sensor after the occurrence of the recovery factor is equal to the threshold value held in the holding unit corresponding to the recovery factor, and chattering is detected, the time until the next restart is determined to be the first time. If the number of times the sensor value is acquired from the sensor after the occurrence of the recovery factor is equal to the threshold value held in the holding unit corresponding to the recovery factor, and no chattering is detected, the device recovery unit is instructed to perform the recovery process. The electronic device according to claim 2 or claim 3, characterized by the above.

5. The main body of the device that forms the image, The main controller controls the main body of the aforementioned device, The system includes a sub-controller that controls the startup and shutdown of the main controller, The aforementioned main controller A recovery control unit, which, upon startup based on the detection by a sensor of the occurrence of a recovery factor that restores the main unit from energy-saving mode, determines the time until the next restart of the main controller to be a second time shorter than the first time, according to the recovery factor, and when it is detected that the recovery factor occurred due to chattering during the next restart, determines the time until the restart to be the first time, A chattering detection unit detects whether the recovery factor occurred due to chattering after the subsequent restart, A notification unit that notifies the subcontroller of the first or second time determined by the recovery control unit, The device recovery unit performs a recovery process for the device body if no chattering is detected by the chattering detection unit after the aforementioned restart. The aforementioned subcontroller is A startup control unit restarts the main controller based on the detection of the occurrence of the recovery factor by the sensor, stops the main controller when the notification unit notifies the first or second time, and restarts the main controller based on the elapsed time of the notified first or second time, It has, The aforementioned first time is set to a few seconds to 10 seconds. An image forming apparatus characterized by the following:

6. A control method for electronic equipment comprising a main controller that controls the main body of the device, and a sub-controller that controls the starting and stopping of the main controller, The recovery control unit of the main controller, upon startup based on the detection by a sensor of a recovery factor that causes the device to recover from energy-saving mode, determines the time until the next restart of the main controller to be a second time, which is shorter than the first time, according to the recovery factor, and when it is detected at the time of the next restart that the recovery factor was caused by chattering, it determines the time until the restart to be the first time. The chattering detection unit of the main controller detects whether the recovery factor was caused by chattering after the next restart. The notification unit of the main controller notifies the sub-controller of the first or second time determined by the recovery control unit. If the device recovery unit of the main controller does not detect chattering by the chattering detection unit after the next restart, it performs the device recovery process for the main unit. The startup control unit of the subcontroller restarts the main controller based on the detection of the occurrence of the recovery factor by the sensor, stops the main controller when the first or second time is notified by the notification unit, and restarts the main controller based on the elapsed time of the notified first or second time. The aforementioned first time is set to a few seconds to 10 seconds. A control method for electronic devices characterized by the following.

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