JP2009043243A - Image forming system, image forming apparatus, and method of recovering from energy-saving mode, and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow an external controller to recover from an energy-saving mode interlockingly with the power-on of an image forming apparatus. <P>SOLUTION: The external controller 1 connected to the image forming apparatus 10 is provided with an energy-saving control unit 6 for detecting a supply of power to the image forming apparatus 10 by a power supply part and performing an energy-saving control of the external controller 1 and a FET 17 for switching a start and a stop of supply of power to an onboard circuit of the external controller 1. Upon detecting the supply of power to the image forming apparatus 10, the energy-saving control unit 6 sends a power control signal 18 for instructing a start of the supply of power to the circuit to the FET 17. Upon receiving the power control signal 18, the FET 17 starts the supply of power to the circuit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming system having an external controller and an image forming apparatus, an image forming apparatus, an energy saving return method, and a program.

  In an image forming system that receives a print request from a client by an external controller and performs printing or reading operation on an image forming apparatus connected to the external controller via an interface, the external controller is set in an energy saving state when the power of the image forming apparatus is turned off. It is desirable to realize a reduction in power consumption and quick start-up of the system by shifting to an external controller that returns from the energy saving state in conjunction with the power-on of the image forming apparatus.

  However, in an image forming system in which the interface between the image forming apparatus and the external controller is Ethernet (registered trademark), when the power supply to the Ethernet circuit is stopped due to the energy saving transition of the external controller, the Ethernet function cannot be used. There is a problem that the external controller cannot be returned from the energy saving state in conjunction with the power-on of the image forming apparatus.

  In order to solve such a problem, the following techniques have been disclosed conventionally.

  In the technique disclosed in Patent Document 1, the spread spectrum communication circuit of the power supply unit control circuit in the printer control circuit performs data communication with the information processing apparatus PC via the distribution line, and the power supply control unit sets the attribute of the communicated data. In response, the power supply circuit is controlled to turn on / off the power supply to the printer controller or printer engine, eliminating the troublesome work of connecting communication lines and control lines, eliminating the need for additional connection lines, and performing image formation. There has been proposed a technique that can achieve power consumption equivalent to powering off during standby.

JP 2003-162398 A

  However, the technique disclosed in Patent Document 1 is a technique for energy saving control when power is supplied to both the information processing apparatus and the image forming apparatus, and the image forming apparatus performs energy saving control from power OFF. I can't.

  The present invention has been made in view of the above, and an image forming system, an image forming apparatus, an energy saving return method, and an external controller that can return from an energy saving state in conjunction with power ON of the image forming apparatus. The purpose is to provide a program.

  In order to solve the above-described problems and achieve the object, an image forming system according to the present invention is an image forming system in which an image forming apparatus and an external controller are connected via a network, and the image forming apparatus includes: An energy saving control unit that includes a power supply unit that supplies power to the image forming apparatus, wherein the external controller detects power supply by the power supply unit of the image forming apparatus and performs energy saving control of the external controller. And a switching unit that switches between start of power supply to the circuit mounted on the external controller and stop of power supply, and when the energy saving control unit detects the power supply to the image forming apparatus, A power control signal for instructing start of power supply to the circuit is transmitted to the switching unit; When receiving the power control signal, characterized in that it starts the power supply to the circuit.

  The image forming apparatus according to the present invention includes a power supply unit that supplies power to the image forming apparatus, and a signal indicating that power supply to the image forming apparatus is started when power supply is started. And a signal transmission unit that transmits the signal to the external controller.

  An energy saving return method according to the present invention is an energy saving return method executed in an image forming system in which an image forming apparatus and an external controller are connected by a network, and the image forming apparatus is connected to the image forming apparatus. A power supply unit that supplies power to the external controller, wherein the energy saving control unit of the external controller detects power supply of the image forming apparatus and performs energy saving control of the external controller; and A switching unit that switches between starting and stopping power supply to a circuit mounted on the external controller, wherein the energy saving control step detects the power supply to the image forming apparatus. Power to instruct the start of power supply to the circuit. Sends a control signal to said switching unit, said switching step, when receiving the power control signal, characterized in that it starts the power supply to the circuit.

  According to another aspect of the invention, there is provided an energy saving control unit configured to detect a power supply by the power supply unit of the image forming apparatus, and to perform energy saving control of the computer. When the power saving control unit detects the power supply to the image forming apparatus, it functions as a switching unit that switches between start of power supply to the circuit mounted on the computer and stop of power supply. A power control signal instructing start of power supply to the circuit is transmitted to the switching unit, and the switching unit starts power supply to the circuit when the power control signal is received.

  According to the present invention, there is an effect that the external controller can recover from the energy saving state in conjunction with the power supply of the image forming apparatus, and the power consumption can be reduced and the system can be quickly started up.

  Exemplary embodiments of an image forming system, an image forming apparatus, an energy saving recovery method, and a program according to the present invention will be described below in detail with reference to the accompanying drawings.

(Embodiment 1)
The image forming system according to the first embodiment supplies power to a circuit that has stopped power supply on the external controller when it is detected by the external controller that power is supplied to the image forming apparatus. By restarting the supply, the external controller can return from the energy saving state in conjunction with the power-on of the image forming apparatus.

  FIG. 1 is a block diagram illustrating a configuration of an image forming system according to the first embodiment. In the image forming system of the present embodiment, an external controller 1 and an image forming apparatus 10 are connected by Ethernet (registered trademark). Here, the external controller 1 and the image forming apparatus 10 are configured to be connected via Ethernet. However, the configuration is not limited thereto. For example, the external controller 1 and the image forming apparatus 10 may be configured to be connected via a high-speed interface such as PCI Express or USB. Good.

  The external controller 1 includes a CPU 2, a ROM 3, a RAM 4, a timer 5 connected to the CPU 2, a timer 5, an energy saving control unit 6 that controls OFF / ON of the FET 17 according to an energy saving transition / restoration factor, an Ethernet I / F 7, and an Ethernet I / F 8. And FET 17.

  The external controller 1 has a function of converting image data transmitted from an external device such as the client PC 9 of FIG. 1 into data that can be printed by the image forming apparatus 10 and data that can be displayed. It has a signal mutual conversion function.

The CPU 2 comprehensively controls each of the ROM 3, RAM 4, timer 5, energy saving control unit 6, Ethernet I / F 7, and Ethernet I / F 8.
Oversee and control.

  The timer 5 has a timer function used when the CPU 2 controls each part of the board.

  When the energy-saving control unit 6 receives a high-level energy-saving return signal 19 from the image forming apparatus 10, the power-supply control signal 18 that controls the gate of the FET 17 turns on the FET 17 to supply power to the portion where the power supply is stopped. Start supplying. Further, when the energy-saving control unit 6 receives the low-level energy-saving return signal 19 from the image forming apparatus 10, the power-supply control signal 18 that controls the gate of the FET 17 turns off the FET 17 and supplies power to the circuit on the external controller. Stop supplying.

  Here, the energy saving return signal 19 is a signal indicating whether or not the power supply from the power supply V0 is started (restarted) in the circuit of the image forming apparatus 10 in which the power supply has been stopped. When the energy saving return signal 19 is at a high level, it indicates that power supply from the power supply V0 has been started (restarted) to the circuit of the image forming apparatus 10 for which power supply has been stopped. In the present embodiment, the energy saving return signal 19 is generated and transmitted to the external controller 1 when power supply to the image forming apparatus 10 is restarted.

  The power source V <b> 1 is a power source that is supplied with power even at the time of energy saving transition. The power source V2 is a power source that stops power supply during energy saving transition.

  The image forming apparatus 10 includes a writing unit 11, a reading unit 12, a CPU 13, and a ROM 14, a RAM 15, a timer 16, and an Ethernet I / F 32 connected to the CPU 13 by a system bus. The CPU 13 performs overall control of the respective parts 14 to 16 and 32 of the board.

  The external controller 1 is connected to the image forming apparatus 10 via the Ethernet I / F 7 via the client PC 9 and the Ethernet I / F 8.

  The FET 17 switches between the start of power supply to the circuit mounted on the external controller 1 and the stop of power supply.

  The energy-saving control unit 6 receives the High-level energy-saving return signal 19 indicating that power supply from the power supply V0 has been started (restarted) to the circuit of the image forming apparatus 10 in which power supply has been stopped, thereby forming an image. The power supply of the apparatus 10 is detected, and energy saving control of the external controller 1 is performed.

  The energy saving return signal 19 is set from the image forming apparatus 10 to the external controller 1 in conjunction with the power supply V0 of the image forming apparatus 10 when the power is turned on, and at a high level when the power is turned off. It is transmitted to the energy saving control unit 6.

  That is, when the energy-saving control unit 6 receives a high-level energy-saving return signal 19 from the image forming apparatus 10, the FET 17 sends an ON power control signal 18 that instructs the start of power supply to the circuit on the external controller 1. To turn on the FET 17. When the FET 17 receives this ON power control signal 18, the FET 17 is turned on and starts supplying power to the circuits on the external controller 1 such as the Ethernet I / F 7.

  On the other hand, when the power of the image forming apparatus 10 is turned off, a low level energy saving return signal 19 is transmitted to the energy saving control unit 6. The energy-saving control unit 6 that has received this low-level energy-saving return signal 19 transmits a power supply control signal 18 instructing OFF to the FET 17, and controls the FET 17 to be OFF. As a result, the FET 17 is turned off, and the power supply to the circuit on the external controller 1 such as the Ethernet I / F 7 is stopped.

  Next, energy saving return processing by the image forming system of Embodiment 1 configured as described above will be described. FIG. 2 is a flowchart illustrating a procedure of energy saving return processing according to the first embodiment.

  When the image forming apparatus 10 is powered off, the energy saving control unit 6 controls the FET 17 to be turned off by the power control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  In a state where the power supply to the Ethernet I / F 7 is stopped in the external controller 1, the energy saving control unit 6 waits to receive a high-level energy saving return signal 19 indicating that the power supply to the image forming apparatus 10 has started. (Step S11).

  When the power supply V0 of the image forming apparatus 10 is turned on from the state where the power supply to the Ethernet I / F 7 of the external controller 1 is stopped, the power supply V0 of the image forming apparatus 10 is started, and the image forming apparatus 10 returns to the energy saving state. The signal 19 is raised from the Low level to the High level and transmitted to the external controller 1.

  When the energy-saving control unit 6 receives this high-level energy-saving return signal 19 (step S11: Yes), it determines that power is supplied to the image forming apparatus 10. And the energy-saving control part 6 sets the power supply control signal 18 to ON, and outputs it to FET17 (step S12). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 1 such as the Ethernet I / F 7 that has been turned on and has stopped supplying power. Thereby, the external controller 1 is returned from the energy saving state.

  In step S11, the next process is not executed while the high-level energy saving return signal is not received (step S11: No).

  As described above, according to the present embodiment, when it is detected that power is supplied to the image forming apparatus 10 by power supply detection, power supply is resumed to the circuit that has stopped power supply on the external controller 1. Accordingly, the external controller 1 can return from the energy saving state in conjunction with the power-on of the image forming apparatus 10.

(Embodiment 2)
The image forming system according to the second embodiment realizes the following functions. That is, after the image forming apparatus 10 is turned on, negotiation is performed for the Ethernet link. At this time, the level of the signal on the Ethernet changes. The external controller 1 detects a change in the level of the signal on the Ethernet, and resumes power supply to the circuit that has stopped power supply on the external controller. Thereby, the external controller 1 can return from the energy saving state in conjunction with the power-on of the image forming apparatus 10.

  FIG. 3 is a block diagram of the configuration of the image forming system according to the second embodiment. In the image forming system of the present embodiment, as in the first embodiment, the external controller 300 and the image forming apparatus 10 are connected by Ethernet (registered trademark). The configuration of the image forming apparatus 10 is the same as that of the first embodiment.

  The external controller 300 includes a CPU 2, a level change detection unit 21, a ROM 3, a RAM 4, a timer 5 connected to the CPU 2 via a system bus, an energy saving control unit 306 that controls OFF / ON of the FET 17 according to an energy saving transition / restoration factor, an Ethernet I / O It has F7, Ethernet I / F8, and FET17. Here, the CPU 2, ROM 3, RAM 4, timer 5, Ethernet I / F 7, Ethernet I / F 8, and FET 17 are the same as those in the first embodiment.

  The level change detection unit 21 detects a change in signal level transmitted and received between the Ethernet I / F 32 and the Ethernet I / F 7. Specifically, the level change detection unit 21 monitors the received signal (RX + −) of Ethernet. Then, the level change detection unit 21 detects a change in the signal level due to the link negotiation performed between the Ethernet I / F 32 and the Ethernet I / F 7 after the image forming apparatus 10 is turned on. When the level change detection unit 21 detects a signal level change due to negotiation, the level change detection unit 21 transmits the energy saving return signal 19 raised to the high level to the energy saving control unit 306.

  When the energy saving control unit 306 receives the high level energy saving return signal 19, the energy saving control unit 306 determines that the signal level between the Ethernet I / F 32 and the Ethernet I / F 7 has changed, that is, the image forming apparatus 10 has been supplied with power. Then, the energy saving control unit 306 transmits an ON power control signal 18 instructing the start of power supply to the circuit on the external controller 300 to the FET 17 and controls the FET 17 to be ON. As in the first embodiment, the FET 17 is turned on when the ON power control signal 18 is received, and starts supplying power to the circuits on the external controller 300 such as the Ethernet I / F 7.

  Next, the energy saving return process by the image forming system of the second embodiment configured as described above will be described. FIG. 4 is a flowchart illustrating a procedure of energy saving return processing according to the second embodiment.

  When the image forming apparatus 10 is powered off, the energy saving control unit 306 controls the FET 17 to be turned off by the power control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  When the power supply of the image forming apparatus 10 is turned on, link negotiation is started between the Ethernet I / F 32 of the image forming apparatus 10 and the Ethernet I / F 7 of the external controller 300. The level change detection unit 21 monitors signals transmitted / received between both Ethernet I / Fs (step S21). When the level of a signal transmitted / received between both Ethernet I / Fs changes due to the negotiation, the level change detection unit 21 detects a level change of the signal due to the negotiation (step S22: Yes). Then, the level change detection unit 21 raises the energy saving return signal 19 to the high level and outputs it to the energy saving control unit 306 (step S23). Here, in step S22, while the signal level change is not detected (step S22: No), the next process is not executed.

  In a state where power supply to the Ethernet I / F 7 is stopped in the external controller 300, the energy saving control unit 306 is in a waiting state for receiving a high-level energy saving return signal 19 indicating that power supply to the image forming apparatus 10 has started. (Step S24). When the energy saving control unit 306 receives the high level energy saving return signal 19 from the level change detection unit 21 (step S24: Yes), it determines that the power is supplied to the image forming apparatus 10.

  And the energy-saving control part 306 sets the power supply control signal 18 to ON, and outputs it to FET17 (step S25). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 300 such as the Ethernet I / F 7 that has been turned on and has stopped supplying power. Thereby, the external controller 300 is returned from the energy saving state.

  As described above, according to the second embodiment, after the image forming apparatus 10 is powered on, negotiation is performed for the Ethernet link, and the level of the signal on the Ethernet changes. When the external controller 300 detects a change in the level of this signal, the external controller 300 determines that power supply to the image forming apparatus 10 has been started (restarted), and supplies power to the circuit that has stopped power supply on the external controller 300. To resume. Therefore, according to the present embodiment, the external controller 300 can return from the energy saving state in conjunction with the power-on of the image forming apparatus 10.

(Embodiment 3)
In the first and second embodiments, the image forming apparatus 10 generates a high-level energy saving return signal 19 indicating that power is supplied to itself and transmits it to the external controller 1300. In the third embodiment, the energy saving return signal is generated on the external controller side, and when the energy saving return signal is generated and detected, the power supply of the image forming apparatus 10 is started to turn on the power of the image forming apparatus. In conjunction with, the external controller can return from the energy-saving state.

  FIG. 5 is a block diagram of the configuration of the image forming system according to the third embodiment. In the image forming system of the present embodiment, as in the first embodiment, the external controller 500 and the image forming apparatus 510 are connected by Ethernet (registered trademark).

  The image forming apparatus 510 includes a writing unit 11, a reading unit 12, a CPU 13, a ROM 14, a ROM 14, a RAM 15, a timer 16, an Ethernet I / F 32, and a PSU (Power Supply Unit) 24 connected to the system bus. Have Here, the writing unit 11, the reading unit 12, the CPU 13, the RAM 15, the timer 16, and the Ethernet I / F 32 are the same as those in the first embodiment.

  The PSU 24 includes an AC / DC converter 26 (hereinafter referred to as “AC / DC 26”), a relay 27, and an AC power source 25 (indicated as “AC 25” in FIG. 5). The PSU 24 converts the AC power supply 25 from AC to DC by the AC / DC 26 and switches power by the relay 27 to supply power to each circuit on the image forming apparatus 510 or stop power supply.

  The external controller 500 includes a CPU 2, a ROM 3, a RAM 4, a timer 5 connected to the CPU 2, a timer 5, an energy saving control unit 506 that controls OFF / ON of the FET 17 according to an energy saving transition / return factor, an Ethernet I / F 7, and an Ethernet I / F 8. And FET 17 and switch 23. Here, the CPU 2, ROM 3, RAM 4, timer 5, Ethernet I / F 7, Ethernet I / F 8, and FET 17 are the same as those in the first embodiment.

  The switch 23 and the power source V1 generate an energy saving return signal. Specifically, when the switch 23 is turned ON, the energy saving return signal 19 that becomes a high level is generated from the power supply V1. Further, when the switch 23 is turned OFF, the energy saving return signal 19 is generated at a low level.

  When the energy-saving control unit 506 receives the high-level energy-saving return signal 19 from the switch 23, the power-supply control signal 18 that controls the gate of the FET 17 turns on the FET 17 to supply power to the portion where the power supply is stopped. To start. Further, when the energy saving control unit 506 receives the low level energy saving return signal 19 from the switch 23, the FET 17 is turned off by the power control signal 18 for controlling the gate of the FET 17, and the power is supplied to the circuit on the external controller. Stop. In the present embodiment, the energy saving return signal 19 is generated on the external controller 500 side.

  The switch 23 is connected to the relay 27 of the PSU 24 of the image forming apparatus 510. For this reason, the energy saving return signal 19 is also transmitted from the switch 23 to the relay 27. When the energy saving return signal 19 is at a high level, the relay 27 is turned on and power is supplied to the image forming apparatus 510. When the energy saving return signal 19 is at the low level, the relay 27 is turned off and the power supply to the image forming apparatus 510 is stopped.

  Next, the energy saving return process by the image forming system of the third embodiment configured as described above will be described. FIG. 6 is a flowchart illustrating a procedure of energy saving return processing according to the third embodiment.

  When the power supply of the image forming apparatus 510 is in the OFF state, the energy saving control unit 506 performs the OFF control of the FET 17 by the power supply control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  When the switch 23 is pressed, the switch 23 is turned on (step S31: Yes), the energy saving return signal 19 becomes a high level, and is transmitted to the energy saving control unit 506 and the relay 27 of the PSU 24 of the image forming apparatus 510. (Step S32).

  In the image forming apparatus 510, the relay 27 is turned on by the high-level energy saving return signal 19, and power is supplied to the image forming apparatus 510 by the PSU 24.

  On the other hand, when the energy saving control unit 506 detects the high level of the energy saving return signal 19 (step S33: Yes), it determines that the power is supplied to the image forming apparatus 510.

  And the energy-saving control part 506 sets the power supply control signal 18 to ON, and outputs it to FET17 (step S34). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 500 such as the Ethernet I / F 7 that has been turned on and has stopped supplying power. Thereby, the external controller 500 is returned from the energy saving state.

  As described above, according to the present embodiment, the external controller 500 generates the energy saving return signal 19, thereby instructing the power supply of the image forming apparatus 510 and starting the power supply of the image forming apparatus 510. The external controller 500 can return from the energy saving state in conjunction with the power ON of the image forming apparatus 510.

(Embodiment 4)
In the fourth embodiment, it is detected that the LED emits light in conjunction with the power-on of the image forming apparatus, and the power supply to the circuit that has stopped the power supply on the external controller is restarted. The external controller can return from the energy saving state in conjunction with the power ON.

  FIG. 7 is a block diagram illustrating a configuration of an image forming system according to the fourth embodiment. In the image forming system of the present embodiment, as in the first embodiment, the external controller 700 and the image forming apparatus 710 are connected by Ethernet (registered trademark). Note that the configuration of the image forming apparatus 710 is the same as that of the first embodiment.

  The image forming apparatus 710 includes a writing unit 11, a reading unit 12, a CPU 13, a ROM 14 connected to the CPU 13, a RAM 15, a timer 16, an Ethernet I / F 32, and an LED 30. Here, the writing unit 11, the reading unit 12, the CPU 13, the ROM 14, the RAM 15, the timer 16, and the Ethernet I / F 32 are the same as those in the first embodiment.

  When the power supply V0 rises and power supply is started, the LED 30 emits light in conjunction with it.

  The external controller 700 includes a CPU 2, a ROM 3, a RAM 4, a timer 5, an optical sensor 29 connected to the CPU 2 via a system bus, an energy saving control unit 706 that controls OFF / ON of the FET 17 according to an energy saving transition / restoration factor, an Ethernet I / F 7, It has Ethernet I / F8 and FET17. Here, the CPU 2, ROM 3, RAM 4, timer 5, Ethernet I / F 7, Ethernet I / F 8, and FET 17 are the same as those in the first embodiment.

  The optical sensor 29 outputs an energy saving return signal 19 to the energy saving control unit 706 when detecting light emission (light signal) of the LED 30. On the other hand, the optical sensor 29 outputs a low-level energy saving return signal 19 when the light emission of the LED 30 is not detected.

  When the energy-saving control unit 706 receives the high-level energy-saving return signal 19 from the optical sensor 29, the power-supply control signal 18 that controls the gate of the FET 17 is turned on to control the power supply to the portion where the power supply is stopped. Start supplying. Further, when the energy saving control unit 706 receives the low level energy saving return signal 19 from the optical sensor 29, the FET 17 is turned off by the power supply control signal 18 for controlling the gate of the FET 17, and the circuit on the external controller 700 is controlled. Stop the power supply.

  Next, the energy saving return process by the image forming system of the fourth embodiment configured as described above will be described. FIG. 8 is a flowchart illustrating a procedure of energy saving return processing according to the fourth embodiment.

  When the power supply of the image forming apparatus 710 is in the OFF state, the energy saving control unit 506 controls the FET 17 to be turned off by the power supply control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  When the power supply of the image forming apparatus 710 is turned on from the state where the power supply to the Ethernet I / F 7 is stopped, the power supply V0 rises and the LED 30 emits light.

  When the light sensor 29 of the external controller 700 detects this light emission (step S41: Yes), the light sensor 29 sets the energy saving return signal 19 to the high level and outputs it to the energy saving control unit 706 (step S42).

  When the energy saving control unit 706 detects the high level of the energy saving return signal 19 (step S43: Yes), it determines that power is supplied to the image forming apparatus 710.

  And the energy-saving control part 706 sets the power supply control signal 18 to ON, and outputs it to FET17 (step S44). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 700 such as the Ethernet I / F 7 that has been turned on and has stopped supplying power. Thereby, the external controller 700 is returned from the energy saving state.

  As described above, according to the present embodiment, the external controller 700 detects the light emission of the LED 30 that emits light in conjunction with the power-on of the image forming apparatus 710 and supplies power to the circuit that has stopped the power supply on the external controller 700. Since the supply is resumed, the external controller 700 can return from the energy saving state in conjunction with the power-on of the image forming apparatus 710.

(Embodiment 5)
In the image forming system according to the first embodiment, the power supply to the external controller is further performed in the case where the power supply to the image forming apparatus is continued for a certain time or more due to the detection of the power supply. By restarting the power supply to the stopped circuit, false detection due to noise is prevented.

  FIG. 9 is a block diagram illustrating a configuration of an image forming system according to the fifth embodiment. In the image forming system according to the present embodiment, as in the first embodiment, the external controller 900 and the image forming apparatus 10 are connected by Ethernet (registered trademark). The configuration of the image forming apparatus 10 is the same as that of the first embodiment.

  The external controller 900 includes a CPU 2, a ROM 3 connected to the CPU 2, a RAM 4, a timer 905, an energy saving control unit 906 that controls OFF / ON of the FET 17 according to an energy saving transition / restoration factor, an Ethernet I / F7, and an Ethernet I / F8. And FET 17. Here, CPU2, ROM3, RAM4, Ethernet I / F7, Ethernet I / F8, and FET 17 are the same as those in the first embodiment.

  The timer 905 counts the timing for synchronizing each part of the substrate, for example, as in the first embodiment. In the present embodiment, the timer 905 further measures the time from the time when the energy saving control unit 906 receives the energy saving return signal 19 in response to a command from the CPU 2.

  When the energy-saving control unit 906 receives the high-level energy-saving return signal 19 from the image forming apparatus 10, the high-level energy-saving return signal 19 is detected continuously for a predetermined time measured by the timer 905 from the reception time point. (Whether or not the high-level energy saving return signal 19 is continuously received for a certain period of time). Then, the energy-saving control unit 906 continues for a certain period of time, and when the high-level energy-saving return signal 19 is detected, the ON power control signal 18 that instructs the start of power supply to the circuit on the external controller 900. Is transmitted to the FET 17, and the FET 17 is ON-controlled. The energy-saving control unit 906 does not transmit the ON power control signal 18 to the FET 17 when the high-level energy-saving return signal 19 is not detected for a certain period of time. Here, the predetermined time is a predetermined time and can be arbitrarily determined.

  Next, energy saving return processing by the image forming system of Embodiment 5 configured as described above will be described. FIG. 10 is a flowchart illustrating a procedure of energy saving return processing according to the fifth embodiment.

  When the image forming apparatus 10 is powered off, the energy saving control unit 906 controls the FET 17 to be turned off by the power control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  In a state where power supply to the Ethernet I / F 7 is stopped in the external controller 900, the energy saving control unit 906 is in a state of waiting for reception of a high-level energy saving return signal 19 indicating that power supply to the image forming apparatus 10 has started. (Step S51).

  When the power supply V0 of the image forming apparatus 10 is turned on from the state where the power supply to the Ethernet I / F 7 of the external controller 900 is stopped, the power supply V0 of the image forming apparatus 10 is started, and the image forming apparatus 10 returns to the energy saving state. The signal 19 is raised from the Low level to the High level and transmitted to the external controller 900.

  When the energy-saving control unit 906 receives this high-level energy-saving return signal 19 (step S51: Yes), it determines that power is supplied to the image forming apparatus 10. Then, the timer 905 starts time measurement, and the energy saving control unit 906 determines whether or not the high level energy saving return signal 19 has been received for a certain period of time (step S52).

  If the high-level energy saving return signal 19 has not been received for a certain period of time (step S52: No), the process returns to step S51, and the energy saving control unit 906 again waits to receive the energy saving return signal 19. .

  On the other hand, when the high-level energy saving return signal 19 is received for a predetermined time in step S52 (step S52: Yes), the energy saving control unit 906 sets the power control signal 18 to ON and outputs it to the FET 17 (Step S53). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 900 such as the Ethernet I / F 7 that has been turned on and has stopped supplying power. Thereby, the external controller 900 is returned from the energy saving state.

  As described above, according to the present exemplary embodiment, power is supplied to the circuit on which power supply on the external controller 900 has been stopped only when the power supply to the image forming apparatus 10 is continuously detected for a certain period of time. Since the process is resumed, erroneous detection due to noise can be prevented when power supply is detected.

(Embodiment 6)
In the sixth embodiment, in the image forming system of the third embodiment, power supply to the image forming apparatus is started only when reception of the energy saving return signal continues for a certain time or more, thereby causing an error due to noise. Prevent detection.

  FIG. 11 is a block diagram illustrating a configuration of an image forming system according to the sixth embodiment. In the image forming system of the present embodiment, as in the first embodiment, an external controller 1100 and an image forming apparatus 510 are connected by Ethernet (registered trademark). Here, the configuration of image forming apparatus 510 is the same as that of the third embodiment.

  The external controller 1100 includes a CPU 2, a ROM 3 connected to the CPU 2, a RAM 4, a timer 905, an energy saving control unit 1106 for controlling the OFF / ON of the FET 17 according to an energy saving transition / restoration factor, an Ethernet I / F7, an Ethernet I / F8. And FET 17 and switch 23. Here, the CPU 2, ROM 3, RAM 4, switch 23, Ethernet I / F 7, Ethernet I / F 8, and FET 17 are the same as those in the third embodiment. Also in the present embodiment, as in the third embodiment, the energy saving return signal 19 is generated on the external controller 1100 side.

  The timer 905 counts, for example, timing for synchronizing each part of the substrate, as in the first and third embodiments. In the present embodiment, similarly to the fifth embodiment, the timer 905 further measures the time from the time when the energy saving control signal 1106 is received by the energy saving return signal 19 in response to a command from the CPU 2.

  When the energy-saving control unit 1106 receives the high-level energy-saving return signal 19 from the switch 23, whether or not the high-level energy-saving return signal 19 has been detected for a certain period of time measured by the timer 905 from the reception point. (Whether or not the high-level energy saving return signal 19 has been continuously received for a certain period of time). Then, the energy-saving control unit 1106 continues for a certain period of time, and when the high-level energy-saving return signal 19 is detected, the ON power control signal 18 that instructs the start of power supply to the circuit on the external controller 1100. Is transmitted to the FET 17, and the FET 17 is ON-controlled. At the same time, the energy saving control unit 1106 transmits an ON power control signal 18 to the relay 27 in the PSU 24 of the image forming apparatus 519 to turn the relay 27 on.

  On the other hand, the energy saving control unit 1106 does not perform the above process when the high level energy saving return signal 19 is not detected for a certain period of time.

  Next, the energy saving return process by the image forming system according to the sixth embodiment configured as described above will be described. FIG. 12 is a flowchart illustrating a procedure of energy saving return processing according to the sixth embodiment.

  When the image forming apparatus 510 is powered off, the energy saving control unit 1106 controls the FET 17 to be turned off by the power control signal 18. In this state, power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  When the switch 23 is pressed, the switch 23 is turned on (step S61: Yes), and the energy saving return signal 19 is at a high level and is transmitted to the energy saving control unit 1106 (step S62).

  When the energy saving control unit 1106 detects the high level of the energy saving return signal 19 (step S63: Yes), the timer 905 starts time measurement, and the energy saving control unit 1106 continues for a certain period of time and continues to the high level energy saving return signal 19. Is determined (step S64).

  If the high level energy saving return signal 19 has not been received for a certain period of time (step S64: No), the process returns to step S63, and the energy saving control unit 1106 again waits to receive the energy saving return signal 19. .

  On the other hand, when the high-level energy saving return signal 19 is received for a predetermined time in step S64 (step S64: Yes), the energy saving control unit 1106 sets the power supply control signal 18 to ON, the FET 17 and the image. Output to the relay 27 of the forming apparatus 510 (step S65). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 1100 such as the Ethernet I / F 7 that has been turned ON and has stopped supplying power. Thereby, the external controller 1100 is returned from the energy saving state.

  Further, in the image forming apparatus 510, the ON power control signal 18 is received and the relay 27 is turned on, and power is supplied to the image forming apparatus 510 by the PSU 24.

  As described above, according to the present embodiment, power is supplied to the circuit that has stopped power supply on the external controller 1100 only when the output of the energy saving return signal is continuously received by the energy saving control unit 1106 for a predetermined time or longer. Since the power supply to the image forming apparatus 510 is started, erroneous detection due to noise can be prevented when detecting the energy saving return signal.

(Embodiment 7)
In the seventh embodiment, the power supply to the image forming apparatus is supplied only when the generation of the energy saving return signal is detected and it is detected that the power supply on the external controller has been stopped. By starting, false detection due to noise is prevented.

  FIG. 13 is a block diagram illustrating a configuration of an image forming system according to the seventh embodiment. In the image forming system of the present embodiment, as in the first embodiment, an external controller 1300 and an image forming apparatus 510 are connected by Ethernet (registered trademark). Here, the configuration of image forming apparatus 510 is the same as that of the third embodiment.

  The external controller 1300 includes a CPU 2, a ROM 3, a RAM 4, a timer 5 connected to the CPU 2, a timer 5, an energy saving control unit 1306 that controls OFF / ON of the FET 17 according to an energy saving transition / restoration factor, Ethernet I / F 7, Ethernet I / F 8. And an FET 17, a switch 23, and a PSU control unit 31. Here, the CPU 2, ROM 3, RAM 4, switch 23, Ethernet I / F 7, Ethernet I / F 8, and FET 17 are the same as those in the third embodiment. The timer 5 is the same as that in the first embodiment. Also in the present embodiment, as in the third embodiment, the energy saving return signal 19 is generated on the external controller 1300 side.

  When the energy-saving control unit 1306 receives the high-level energy-saving return signal 19 from the switch 23, the power-supply control signal 18 that controls the gate of the FET 17 turns on the FET 17 and supplies power to the portion where the power supply is stopped. To start. The ON power control signal 18 output from the energy saving control unit 1306 branches and is also output to the PSU control unit 31. In addition, when the energy saving control unit 1306 receives the low level energy saving return signal 19 from the switch 23, the FET 17 is turned OFF by the power control signal 18 that controls the gate of the FET 17, and the power to the circuit on the external controller 1300 is controlled. Stop supplying.

  The PSU control unit 31 is supplied with the V2 power by receiving the ON power control signal 18 from the energy saving control unit 1306. The PSU control unit 31 is connected to the PSU 24 of the image forming apparatus 510, specifically, the relay 27 in the PSU 24. When the PSU control unit 31 receives the high-level energy saving return signal 19 from the energy saving control unit 1306 and the power source V2 is supplied (that is, when the ON power control signal 18 is received from the energy saving control unit 1306). Only, the PSU control signal 33 is raised to the high level and transmitted to the relay 27. Under other conditions, the PSU control signal 33 is at a low level.

  In the image forming apparatus 510, when the PSU control signal 33 is at a high level, the relay 27 is turned on and power is supplied to the image forming apparatus 510. When the PSU control signal 33 is at the low level, the supply of power to the image forming apparatus 510 is stopped.

  Next, an energy saving return process by the image forming system according to the seventh embodiment configured as described above will be described. FIG. 14 is a flowchart illustrating a procedure of energy saving return processing according to the seventh embodiment.

  When the image forming apparatus 510 is powered off, the energy saving control unit 1306 controls the FET 17 to be turned off by the power control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  When the switch 23 is pressed, the switch 23 is turned on (step S71: Yes), and the energy saving return signal 19 becomes a high level and is transmitted to the energy saving control unit 1306 and the PSU control unit 31 (step S72).

  When the energy saving control unit 1306 detects the high level of the energy saving return signal 19 (step S73: Yes), it sets the power supply control signal 18 to ON and outputs it to the FET 17 and the PSU control unit 31 (step S74). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 1300 such as the Ethernet I / F 7 that has been turned ON and has stopped supplying power. Thereby, the external controller 1300 is returned from the energy saving state.

  On the other hand, the PSU control unit 31 determines whether or not the power V2 is supplied by receiving the high-level energy saving return signal 19 and receiving the ON power control signal 18 (step S75). Then, when the high-level energy saving return signal 19 is received at step S72 and the power source V2 is supplied at step S74 (step S75: Yes), the high-level PSU control signal 33 is transmitted to the relay 27 of the PSU 24. (Step S76). As a result, in the image forming apparatus 510, the relay 27 is turned on, and power is supplied to the image forming apparatus 510 by the PSU 24.

  As described above, in the present embodiment, the power supply of the image forming apparatus is detected only when the generation of the energy saving return signal is detected and the power supply to the circuit that has stopped the power supply on the external controller is detected. By starting the supply, the false detection due to noise is prevented.

(Embodiment 8)
Also in the eighth embodiment, the power supply of the image forming apparatus is supplied only when the generation of the energy saving return signal is detected and it is detected that the power supply to the circuit that has stopped the power supply on the external controller is restarted. By starting, false detection due to noise is prevented.

  FIG. 15 is a block diagram illustrating a configuration of an image forming system according to the eighth embodiment. In the image forming system of the present embodiment, as in the first embodiment, an external controller 1500 and an image forming apparatus 510 are connected by Ethernet (registered trademark). Here, the configuration of image forming apparatus 510 is the same as that of the third embodiment.

  The external controller 1500 includes a CPU 2, a ROM 3 connected to the CPU 2, a RAM 4, a timer 905, an energy saving control unit 1506 for controlling the OFF / ON of the FET 17 according to an energy saving transition / restoration factor, an Ethernet I / F7, and an Ethernet I / F8. And a FET 17, a switch 23, and a PSU control unit 1531. Here, the CPU 2, ROM 3, RAM 4, switch 23, Ethernet I / F 7, Ethernet I / F 8, and FET 17 are the same as those in the seventh embodiment. The timer 905 is the same as that in the fifth embodiment. Also in the present embodiment, as in the third embodiment, the energy saving return signal 19 is generated on the external controller 1500 side.

  When the energy-saving control unit 1506 receives the high-level energy-saving return signal 19 from the switch 23, the energy-saving control unit 1506 determines whether or not the energy-saving return signal 19 has been received continuously for a certain period of time measured by the timer 905 from the time of reception. . Then, the energy saving control unit 1506 controls the FET 17 to be turned on by the power control signal 18 that controls the gate of the FET 17 when the energy saving control unit 1506 receives the energy saving return signal 19 continuously for a predetermined time. The power supply to the part where the supply is stopped is started. In addition, the ON power control signal 18 transmitted from the energy saving control unit 1506 is branched and output to the PSU control unit 1531.

  The PSU control unit 1531 is supplied with V2 power by receiving an ON power control signal. The PSU control unit 1531 is connected to the PSU 24 of the image forming apparatus 510, specifically, the relay 27 in the PSU 24. The PSU control unit 1531 raises the PSU control signal 33 to the high level and transmits it to the relay 27 only when the power supply V2 is supplied. Under other conditions, the PSU control signal 33 is at a low level.

  In the image forming apparatus 510, when the PSU control signal 33 is at a high level, the relay 27 is turned on and power is supplied to the image forming apparatus 510. When the PSU control signal 33 is at the low level, the supply of power to the image forming apparatus 510 is stopped.

  Next, an energy saving return process by the image forming system according to the eighth embodiment configured as described above will be described. FIG. 16 is a flowchart illustrating a procedure of energy saving return processing according to the eighth embodiment.

  When the power supply of the image forming apparatus 510 is in the OFF state, the energy saving control unit 1506 performs OFF control of the FET 17 by the power supply control signal 18. In this state, the power supply to the Ethernet I / F 7 is stopped. The energy saving return process is a start-up process from a state in which the power supply to the Ethernet I / F 7 is stopped.

  When the switch 23 is pressed, the switch 23 is turned on (step S81: Yes), and the energy saving return signal 19 becomes a high level and is transmitted to the energy saving control unit 1506 (step S82).

  When the energy saving control unit 1506 detects the high level of the energy saving return signal 19 (step S83: Yes), the timer 905 starts time measurement, and the energy saving control unit 1506 continues for a certain period of time and continues to a high level energy saving return signal. It is determined whether or not 19 is received (step S84).

  If the high-level energy saving return signal 19 has not been received for a certain period of time (step S84: No), the process returns to step S83, and the energy saving control unit 1506 again waits to receive the energy saving return signal 19. .

  On the other hand, when the high-level energy saving return signal 19 is received for a predetermined time in step S84 (step S84: Yes), the energy saving control unit 1506 sets the power control signal 18 to ON, and the FET 17 and PSU. It outputs to the control part 1531 (step S85). The FET 17 that has received the ON power control signal 18 supplies power to a circuit on the external controller 1500 such as the Ethernet I / F 7 that has been turned on and has stopped supplying power. Thereby, the external controller 1500 is returned from the energy saving state.

  On the other hand, the PSU control unit 1531 determines whether or not the power V2 is supplied by receiving the ON power control signal 18 (step S86). When the power source V2 is supplied in step S85 (step S86: Yes), a high level PSU control signal 33 is transmitted to the relay 27 of the PSU 24 (step S87). As a result, in the image forming apparatus 510, the relay 27 is turned on, and power is supplied to the image forming apparatus 510 by the PSU 24.

  As described above, in this embodiment, the power supply of the image forming apparatus is detected only when the generation of the energy saving return signal is detected and the power supply to the circuit that has stopped the power supply on the external controller is detected. By starting the supply, the false detection due to noise is prevented.

  Note that the energy saving return program executed by the external controller of the first to eighth embodiments is provided by being incorporated in advance in a ROM or the like.

  The energy saving return program executed by the external controller of the first to eighth embodiments is an installable or executable file in a CD-ROM, flexible disk (FD), CD-R, DVD (Digital Versatile Disk). For example, the program may be recorded on a computer-readable recording medium.

  Further, the energy saving return program executed by the external controller according to the first to eighth embodiments may be provided by being stored on a computer connected to a network such as the Internet and downloaded via the network. . Moreover, you may comprise so that the energy-saving return program performed with the external controller of Embodiment 1-8 may be provided or distributed via networks, such as the internet.

  The energy saving return program executed by the external controller of the first to eighth embodiments has a module configuration including the above-described units. As actual hardware, the CPU (processor) reads the energy saving return program from the ROM. By executing, the above-described units are loaded on the main storage device, and the above-described units are generated on the main storage device.

  It should be noted that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

1 is a block diagram illustrating a configuration of an image forming system according to a first embodiment. 3 is a flowchart illustrating a procedure of energy saving return processing according to the first embodiment. FIG. 3 is a block diagram illustrating a configuration of an image forming system according to a second embodiment. 10 is a flowchart illustrating a procedure of energy saving return processing according to the second embodiment. FIG. 4 is a block diagram illustrating a configuration of an image forming system according to a third embodiment. 10 is a flowchart illustrating a procedure of energy saving return processing according to the third embodiment. FIG. 6 is a block diagram illustrating a configuration of an image forming system according to a fourth embodiment. 14 is a flowchart illustrating a procedure of energy saving return processing according to the fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of an image forming system according to a fifth embodiment. 10 is a flowchart illustrating a procedure of energy saving return processing according to the fifth embodiment. FIG. 10 is a block diagram illustrating a configuration of an image forming system according to a sixth embodiment. 18 is a flowchart illustrating a procedure of energy saving return processing according to the sixth embodiment. FIG. 10 is a block diagram illustrating a configuration of an image forming system according to a seventh embodiment. 18 is a flowchart illustrating a procedure of energy saving return processing according to the seventh embodiment. FIG. 10 is a block diagram illustrating a configuration of an image forming system according to an eighth embodiment. 20 is a flowchart illustrating a procedure of energy saving return processing according to an eighth embodiment.

Explanation of symbols

1,300,500,700,900,1100,1300,1500 external controller 5,905 timer 6,306,506,906,1106,1306,1506 energy saving control unit 10,510,710 image forming apparatus 11 writing unit 16 timer 18 Power control signal 19 Energy saving return signal 21 Level change detection unit 23 Switch 26 AC / DC converter 27 Relay 29 Optical sensor 31, 1531 PSU control unit 33 PSU control signal

Claims (16)

An image forming system in which an image forming apparatus and an external controller are connected via a network,
The image forming apparatus includes:
A power supply unit that supplies power to the image forming apparatus;
The external controller is
An energy saving control unit that detects power supply by the power supply unit of the image forming apparatus and performs energy saving control of the external controller;
A switching unit that switches between the start of power supply and the stop of power supply to the circuit mounted on the external controller,
The energy saving control unit transmits a power control signal instructing start of power supply to the circuit to the switching unit when the power supply to the image forming apparatus is detected.
The image forming system, wherein the switching unit starts supplying power to the circuit when the power control signal is received. The external controller is
A timer for measuring a predetermined time from the time when the power supply to the image forming apparatus is detected;
The image according to claim 1, wherein the energy saving control unit transmits the power control signal to the switching unit when the power supply to the image forming apparatus is continuously detected for the predetermined time. Forming system.   The energy saving control unit determines that the power supply to the image forming apparatus has been detected when an energy saving return signal indicating that the power supply to the image forming apparatus is started is received from the image forming apparatus. The image forming system according to claim 1. The external controller further includes a level change detection unit that detects a level change of the signal of the network,
The image forming system according to claim 1, wherein the energy saving control unit determines that the power supply to the image forming apparatus is detected when the level change is detected. When the level change detection unit detects a level change of the signal of the network, the level change detection unit transmits an energy saving return signal indicating that power supply to the image forming apparatus is started to the energy saving control unit,
The image forming system according to claim 4, wherein the energy saving control unit determines that power supply to the image forming apparatus is detected when the energy saving return signal is received. The image forming apparatus includes:
A light emitting unit that emits light in conjunction with power supply to the image forming apparatus,
The external controller is
A light emission detection unit for detecting light emission of the light emission unit,
The image forming system according to claim 1, wherein the energy saving control unit determines that the power supply to the image forming apparatus is detected when the light emission detecting unit detects light emission of the light emitting unit. . When the light emission detection unit detects light emission of the light emission unit, the light emission detection unit transmits an energy saving return signal indicating that power supply to the image forming apparatus is started to the energy saving control unit,
The image forming system according to claim 6, wherein the energy saving control unit determines that power supply to the image forming apparatus is detected when the energy saving return signal is received. The external controller is
A signal generation unit that generates an energy saving return signal instructing start of power supply, and transmits the generated energy saving return signal to the energy saving control unit and the power supply unit of the image forming apparatus;
The power supply unit starts power supply to the image forming apparatus when the energy saving return signal is received,
The image forming system according to claim 1, wherein the energy saving control unit transmits the power control signal to the switching unit when the energy saving return signal is received. The external controller is
A signal generation unit that generates an energy saving return signal instructing start of power supply, and transmits the generated energy saving return signal to the energy saving control unit;
A timing unit that measures a predetermined time from the time when the energy saving control unit receives the energy saving return signal;
The energy saving control unit transmits the power control signal to the switching unit and the power supply unit when the energy saving return signal is continuously received for the predetermined time. The image forming system described. The external controller is
A power supply control unit that transmits a power supply control signal instructing start of power supply to the image forming apparatus to the power supply unit of the image forming apparatus;
A signal generation unit that generates an energy saving return signal that instructs the start of power supply to the external controller, and transmits the generated energy saving return signal to the energy saving control unit and the power supply control unit;
When the power supply control unit receives the energy saving return signal and the power control signal, the power supply control unit transmits the power supply control signal to the power supply unit.
The image forming system according to claim 1, wherein the energy saving control unit transmits the power control signal to the switching unit and the power supply control unit when the energy saving return signal is received. The external controller is
A power supply control unit that transmits a power supply control signal instructing start of power supply to the image forming apparatus to the power supply unit of the image forming apparatus;
A signal generation unit that generates an energy saving return signal that instructs the start of power supply to the external controller, and transmits the generated energy saving return signal to the energy saving control unit;
A time measuring unit that measures a predetermined time from the time when the energy saving control unit receives the energy saving return signal; and
When the energy saving control unit receives the energy saving return signal, the power saving control unit transmits the power control signal to the switching unit and the power supply control unit,
The image forming system according to claim 1, wherein the power supply control unit transmits the power supply control signal to the power supply unit when the power supply control signal is received. An image forming apparatus,
A power supply unit for supplying power to the image forming apparatus;
A signal transmission unit that transmits a signal indicating that power supply to the image forming apparatus is started to the external controller when power supply is started;
An image forming apparatus comprising:   2. The light emitting unit that emits light in conjunction with power supply, and transmits an optical signal from the light emitting unit as a signal indicating that power supply to the image forming apparatus is started. 12. The image forming apparatus according to 12.   The image forming apparatus according to claim 12, further comprising a signal receiving unit that receives a signal indicating that power supply to the image forming apparatus starts from the external controller. An energy saving return method executed in an image forming system in which an image forming apparatus and an external controller are connected by a network,
The image forming apparatus includes a power supply unit that supplies power to the image forming apparatus.
An energy saving control step in which the energy saving control unit of the external controller detects power supply of the image forming apparatus and performs energy saving control of the external controller;
A switching step of switching between the start of power supply to the circuit mounted on the external controller and the stop of power supply, wherein the switching unit of the external controller includes,
The energy saving control step transmits a power control signal instructing start of power supply to the circuit to the switching unit when the power supply to the image forming apparatus is detected.
The energy saving recovery method according to claim 1, wherein the switching step starts power supply to the circuit when the power control signal is received. A computer connected to the image forming apparatus via a network
An energy saving control unit that detects power supply by the power supply unit of the image forming apparatus and performs energy saving control of the computer;
A switching unit that switches between start of power supply and stop of power supply to a circuit mounted on the computer,
The energy saving control unit transmits a power control signal instructing start of power supply to the circuit to the switching unit when the power supply to the image forming apparatus is detected.
The switching unit starts power supply to the circuit when the power control signal is received.

Images