JP6199105B2 - Electronic apparatus and image forming apparatus - Google Patents

Description

  The present invention relates to an electronic apparatus and an image forming apparatus, and can be applied to, for example, a printer that supports a plurality of operation modes with different power consumption.

Normally, a printer installed in an office or the like is continuously activated for a long time, but the actual print processing period is shorter than the activated time. For this reason, some conventional printers are compatible with an operation mode (hereinafter referred to as “power saving operation mode”) that operates with less power consumption than the printable state and waits for the start of print processing. In the following, the state in which the printer is operating normally (printable state, in other words, the state that is not the power saving operation mode) will be referred to as the “normal operation mode” in the following. As such a printer, for example, there is a printer described in Patent Document 1.

  In the printer described in Patent Document 1, a sub-processor that can perform only processing (network control or the like) that is at least necessary when operating in the power saving operation mode, and processing (image) that is required in the normal operation mode. And a main processor capable of performing processing including control of the forming apparatus and the like. In the printer described in Patent Document 1, when operating in the normal operation mode, the power supply to the sub processor is stopped, and when operating in the power saving operation mode, the power supply to the main processor is stopped. , Standby power consumption can be reduced.

JP 2011-852 A

  However, in a conventional printer, the power consumption varies greatly between when operating in the power saving operation mode and when operating in the normal operation mode, so when operating at a low load as in the power saving operation mode. There is a problem that the power supply efficiency is deteriorated (lower than the normal operation mode).

  Therefore, there is a demand for an electronic apparatus and an image forming apparatus that can operate efficiently in a power source even when operating in an operation mode with low power consumption while supporting a plurality of operation modes with different power consumption.

The electronic device according to the first aspect of the present invention includes (1) a first voltage supply unit, a second voltage supply unit having a smaller capacity than the first voltage supply unit, and (2) a function of the electronic device. A main body having such a configuration; and (3) a control process for performing control processing relating to the main body, the control being driven by a voltage using the first voltage supply unit or the second voltage supply unit as a supply source. And (4) a switching unit that switches a supply source of a voltage to be applied to the control unit to either the first voltage supply unit or the second voltage supply unit. The control unit can operate in either a first operation state that operates with a predetermined power consumption or a second operation state that operates in a state with lower power consumption than the first operation state. (6) The switching unit marks the control unit when the control unit shifts to the second operation state. The voltage supply source to be switched is switched to the second voltage supply unit, and when the control unit shifts to the first operation state, the voltage supply source to be applied to the control unit is changed to the first voltage supply unit. A power storage unit that stores power based on a voltage applied from the second voltage supply unit to the switching unit; and (8) the switching unit applies to the control unit. When switching the voltage supply source from the first voltage supply unit to the second voltage supply unit, after the voltage supply from the first voltage supply unit is cut off, the second voltage supply unit is (9) The switching unit supplies the power stored in the power storage unit after the voltage supply from the first voltage supply unit is cut off. A voltage as a source is applied to the control unit .

The image forming apparatus according to the second aspect of the invention includes (1) a first voltage supply unit, a second voltage supply unit having a smaller capacity than the first voltage supply unit, and (2) image formation on a medium. An image forming unit that performs processing, and (3) performs control processing related to the image forming unit, and is driven by a voltage using the first voltage supply unit or the second voltage supply unit as a supply source. A control unit; and (4) a switching unit that switches a supply source of a voltage to be applied to the control unit to either the first voltage supply unit or the second voltage supply unit. The control unit can operate in either a first operation state that operates with a predetermined power consumption or a second operation state that operates with a power consumption lower than the first operation state. (6) When the control unit shifts to the second operation state, the switching unit is configured to control the control unit. The voltage supply source to be applied is switched to the second voltage supply unit, and when the control unit shifts to the first operation state, the voltage supply source to be applied to the control unit is changed to the first voltage supply unit. (7) further comprising a power storage unit that stores electric power based on a voltage applied from the second voltage supply unit to the switching unit, and (8) the switching unit is applied to the control unit. When the voltage supply source to be switched is switched from the first voltage supply unit to the second voltage supply unit, the voltage supply from the first voltage supply unit is cut off, and then the second voltage supply unit And (9) the switching unit uses the power stored in the power storage unit after the voltage supply from the first voltage supply unit is interrupted. A voltage as a supply source is applied to the control unit.

  According to the present invention, it is possible to provide an electronic apparatus and an image forming apparatus that can operate efficiently in a power supply even when operating in an operation mode with low power consumption while supporting a plurality of operation modes with different power consumption. it can.

FIG. 2 is a block diagram illustrating a functional configuration of the printer according to the first embodiment. It is explanatory drawing shown about the internal structure of the power supply switching circuit part which comprises the printer which concerns on 1st Embodiment. 6 is a flowchart illustrating an operation when the printer according to the first embodiment shifts from a power-off state to a normal operation mode. 6 is a timing chart illustrating an operation when the printer according to the first embodiment shifts from a power-off state to a normal operation mode. 4 is a flowchart illustrating an operation when the printer according to the first embodiment shifts from a normal operation mode to a power saving operation mode. 4 is a timing chart illustrating an operation when the printer according to the first embodiment shifts from a normal operation mode to a power saving operation mode. 3 is a flowchart illustrating an operation when the printer according to the first embodiment shifts from a power saving operation mode to a normal operation mode. 3 is a timing chart illustrating an operation when the printer according to the first embodiment shifts from a power saving operation mode to a normal operation mode. 5 is a flowchart illustrating an operation when the printer according to the first embodiment shifts from a normal operation mode to a power-off state. It is the block diagram shown about the functional structure of the printer which concerns on 2nd Embodiment. It is explanatory drawing shown about the internal structure of the power switching circuit part which comprises the printer which concerns on 2nd Embodiment. 10 is a flowchart illustrating an operation when the printer according to the second embodiment shifts from a power-off state to a normal operation mode. 10 is a timing chart illustrating an operation when the printer according to the second embodiment shifts from a power-off state to a normal operation mode. 10 is a flowchart illustrating an operation when the printer according to the second embodiment shifts from a normal operation mode to a power saving operation mode. 10 is a timing chart illustrating an operation when the printer according to the second embodiment shifts from a normal operation mode to a power saving operation mode. 10 is a flowchart illustrating an operation when the printer according to the second embodiment shifts from a power saving operation mode to a normal operation mode. 10 is a timing chart illustrating an operation when the printer according to the second embodiment shifts from the power saving operation mode to the normal operation mode. It is the block diagram shown about the functional structure of the printer which concerns on 3rd Embodiment. 10 is a flowchart illustrating an operation when the printer according to the third embodiment shifts from a normal operation mode to a second power saving operation mode. 10 is a timing chart illustrating an operation when the printer according to the third embodiment shifts from a normal operation mode to a second power saving operation mode. 10 is a flowchart illustrating an operation when the printer according to the third embodiment shifts from a second power saving operation mode to a normal operation mode. 14 is a timing chart illustrating an operation when the printer according to the third embodiment shifts from the second power saving operation mode to the normal operation mode.

(A) First Embodiment Hereinafter, a first embodiment of an electronic apparatus and an image forming apparatus according to the present invention will be described in detail with reference to the drawings. Hereinafter, an example in which the electronic apparatus and the image forming apparatus of the present invention are applied to a printer will be described.

(A-1) Configuration of the First Embodiment FIG. 1 is a block diagram showing the overall configuration of the printer 1 of this embodiment.

  The printer 1 includes an image forming engine 110 as an image forming unit (main body unit) that forms an image on a print medium. Further, as a component for controlling the image forming engine 110, a printer control unit 105, It has a power saving control unit 104, a CPU 121 as a control unit, a flash memory 120 as a nonvolatile memory, and RAMs 122 and 125 as volatile memories (DRAM). Further, the printer 1 includes a power plug 101 for connection to an external power source (not shown) (for example, an AC power outlet), a low voltage power source 102 as a low voltage power device, a high voltage power source 119 as a high voltage power device, A PchFET 106, a power switch 107, a DC / DC converter 109, a DC / DC converter 123, and a power switching circuit unit 124 are also provided.

  In this embodiment, the image forming engine 110 performs an electrophotographic image forming process (an image forming process in which a developer image (toner image) based on an electrostatic latent image is transferred to a printing paper and fixed). It shall be possible. The image forming method (printing processing method) supported by the image forming engine 110 is not limited to the electrophotographic method, and other image forming methods (for example, an ink method or a dot impact method) may be applied. it can.

  The printer control unit 105 controls each component of the image forming engine 110, performs image processing of supplied print data (image data) (for example, processing that the image forming engine 110 converts into signals used for image formation), and the like. It has a function. As the printer control unit 105, various control configurations corresponding to the configuration of the image forming engine 110 (for example, control units used in various printers) can be applied. In addition, a RAM 125 is connected to the printer control unit 105. The printer control unit 105 develops and executes an image formation control program for controlling the image formation engine 110 in the RAM 125. The printer control unit 105 also stores various data (data used in the image formation control program) used for control of the image formation engine 110 in the RAM 125. The printer control unit 105 also develops image data (such as bitmap data generated during the image forming process by the image forming engine 110) based on the print data input from the host PC 2 on the RAM 125 and temporarily stores the image data. Remember.

  The CPU 121, the RAM 122, and the flash memory 120 constitute a computer for executing a device control program that performs overall control of the printer 1. The flash memory 120 stores the above-described device control program and various data (such as parameters required for executing the device control program). The CPU 121 reads an apparatus control program or the like from the flash memory 120 and expands it on the RAM 122 for execution at the time of activation. The flash memory 120 also stores data used by the apparatus control program and the image formation control program executed by the printer control unit 105. The CPU 121 reads an image formation control program and data used in the image formation control program and supplies them to the printer control unit 105 at the time of activation.

In addition, the CPU 121 includes a communication circuit 121a that functions as a communication interface (I / O interface) with the printer control unit 105, a communication circuit 121b that functions as a communication interface (I / O interface) with the RAM 122, and a circuit inside the CPU 121. And a clock circuit 121c for outputting a clock signal for controlling the drive timing of the signal. Although not shown in FIG. 1, the CPU 121 includes other circuit configurations necessary for the CPU, such as an arithmetic circuit, a cache circuit, and a register circuit. In addition, the CPU 121 stops some functions and operates with less power consumption than normal (printing process enabled state) (hereinafter referred to as “sleep state” or “second operation state”). It can transition to. Specifically, when the CPU 121 enters a sleep state, the CPU 121 stops the clock circuit 121c, waits in a state where only interrupt processing based on an interrupt signal described later can be performed, and reduces power consumption during standby. In the following, a state where the CPU 121 activates a function necessary for normal time (when printing) (a state where the CPU 121 is not in a sleep state) is referred to as an “operation state” or a “ first operation state”.

  As the CPU 121, various CPUs capable of transitioning to the sleep state can be used. Here, it is assumed that the CPU 121 employs a power consumption of 10 W in the operating state and a power consumption of 1 W in the sleep state.

  Further, the printer 1 receives print data (print job data) input from an external host PC 2 that can be connected via an interface such as a LAN or USB (not shown), and performs printing (to print paper) based on the print data. (Printing process) can be performed.

  The low-voltage power supply 102 as a second voltage supply unit that is a low-voltage power supply device includes a sub power supply 111, a relay circuit 112, and a main power supply 113 as a first voltage supply unit. In the low voltage power source 102, the sub power source 111 and the relay circuit 112 are connected to the power plug 101.

  The sub power supply 111 outputs a sub power supply voltage E5VS0 of DC 5V. The sub power supply voltage E5VS0 is input to the power-off control unit 103 and the source terminal of the PchFET 106.

  The power-off control unit 103 and the power saving control unit 104 have a function of performing power control in the printer 1. The power saving control unit 104 can be configured by using, for example, an IC chip such as an ASIC capable of performing signal processing for explaining operations described later. In addition, the power-off control unit 103 can be configured using a microcomputer including an interface for transmitting / receiving signals to / from the outside and an ADC (Analog to Digital Converter, ADC 117 in FIG. 1) having a terminal capable of measuring voltage. .

  The power-off control unit 103 is connected to the power switch 107, and receives the PWRSWON-N signal pulled up by the resistor 114 to the sub power supply voltage E5VS0. The power switch 107 is connected to the ground. When the power switch 107 is pressed, a Low level PWRSWON-N signal is input to the power-off control unit 103, and when not pressed, a High level PWRSWON-N signal is output. The power is input to the power-off control unit 103.

  The power-off control unit 103 outputs a SUBPWRON-N signal as a control signal for performing control related to the sub power source 111. The signal line of the SUBPWRON-N signal output from the power-off control unit 103 is connected to the gate terminal of the PchFET 106. The SUBPWRON-N signal of the power-off control unit 103 has an output specification of an open drain that is pulled up to E5VS0 by the resistor 116. The PchFET 106 is turned on when SUBPWRON-N is at a low level. The PchFET 106 is turned off when SUBPWRON-N is at a high level.

  The sub power supply voltage E5VS output from the drain terminal of the PchFET 106 is input to the power saving control unit 104 that is the first control unit, the ADC 117 of the power off control unit 103, and the power supply switching circuit unit 124 that is the switching unit.

  An OFFMODE-P signal that is a sub power supply stop notification signal output from the power-off control unit 103 is input to the power-saving control unit 104. Note that the OFFMODE-P signal (signal line of the OFFMODE-P signal) has an open drain output specification that is pulled up to 5 VS by the resistor 118.

  An AUTOOFF_OK-P signal (a signal for responding to the OFFMODE-P signal), which is a sub power supply stop permission signal output from the power saving control unit 104, is input to the power off control unit 103.

  The power saving control unit 104 has a control process related to the power saving operation mode of the printer 1 and a function of receiving print data from the outside (the host PC 2 in this embodiment). The power saving control unit 104 outputs a Powersave-N signal for performing control processing related to the power saving operation mode of the printer 1. The power saving control unit 104 converts print data input from the outside into image data and outputs the image data to the printer control unit 105. The printer control unit 105 outputs a status notification signal to the power saving control unit 109.

  The Powersave-N signal output from the power saving control unit 104 is input to the relay circuit 112, the power-off control unit 103, and the power supply switching circuit unit 124. When Powersave-N changes from Low level to High level, the relay circuit 112 is turned on, the AC voltage from the power plug 101 is input to the main power supply 113, and the main power supply voltage E5V rises (steps up from 0V to 5V). On the other hand, when Powersave-N changes from the High level to the Low level, the relay circuit 112 is turned off, the AC voltage from the power plug 101 is not input to the main power supply 113, and the main power supply voltage E5V is stopped (from 5V to 0V). To step down).

  The main power supply 113 outputs a direct current 5V voltage (hereinafter referred to as “main power supply voltage E5V”) and a direct current 24V voltage (hereinafter referred to as “main power supply voltage E24V”) and supplies them to the printer control unit 105. . The main power supply voltage E5V is input to the DC / DC converter 109, stepped down (voltage converted) to two voltages 3.3V and 1.2V, and each voltage is supplied to the printer control unit 105. In FIG. 1, for convenience of illustration, there is only one signal line output from the DC / DC converter 109, but in actuality, it is output using a signal line (terminal) for each output voltage. The The main power supply voltage E5V is input to the power supply switching circuit unit 124. The 3.3V voltage stepped down (voltage converted) by the DC / DC converter 109 is used as a power source (IO power source) for signal transmission and reception in the printer control unit 105, and the 1.2V voltage is an internal control. It becomes a power source (core power source) for processing and data processing.

  In the main power supply 113, a capacitor 113a for stabilizing the output voltage is inserted into the output terminal of the main power supply voltage E24V. In the main power supply 113, a capacitor 113b for stabilizing the output voltage is inserted into the output terminal of the main power supply voltage E5V.

  In this embodiment, the main power supply voltage E24V and the main power supply voltage E5V are also supplied to the image forming engine 110 via the printer control unit 105, respectively. The voltage E5V may be directly supplied to the image forming engine 110 (the main power supply 113 and the image forming engine 110 are directly connected).

  The high-voltage power supply 119 applies a high-voltage to a device that operates at a high voltage in the printer 1 (for example, a device that needs to supply a voltage of 1000 V or higher, such as a transfer roller (not shown) of the image forming engine 110). It is assumed that the high voltage power supply 119 operates based on the control of the printer control unit 105. The printer 1 may have a configuration that can reduce the power consumption of the high-voltage power supply 119, but detailed description thereof is omitted because it is not directly related to the technical features of the present invention.

  In response to the Powersave-N signal, the power supply switching circuit unit 124 outputs the power supply voltage ECPU5V using either the sub power supply voltage E5VS or the main power supply 113 as the supply source from the drain terminal of the PchFET 106 and supplies it to the DC / DC converter 123. Supply.

The DC / DC converter 123 steps down the power supply voltage ECPU5V (voltage conversion) and outputs three power supply voltages 1.8V, 1.5V, and 0.9V. In FIG. 1, there is only one signal line output from the DC / DC converter 123 for convenience of illustration, but in reality, the signal line (terminal) is output for each voltage to be output. The 1.8V and output from the DC / DC converter 123, the power supply voltage of 0.9 V is supplied to the CPU121 respectively. The 1.8 V power supply voltage stepped down (voltage converted) by the DC / DC converter 109 is used as a power supply (IO power supply) for signal transmission and reception in the CPU 121. The 0.9 V power supply voltage stepped down (voltage converted) by the DC / DC converter 109 serves as a power supply (core power supply) for arithmetic processing and the like of the CPU 121.

  A WAKEINT-P signal that is a return instruction signal from the power saving mode is input to the CPU 121 from the power saving control unit 104. When the print data is supplied from the host PC 2, the power saving control unit 104 receives a WAKEINT-P signal to the CPU 121.

  While operating in the power saving operation mode, the CPU 121 is activated by an interrupt process based on the supply of the WAKEINT-P signal, and starts a process for returning to the normal mode. That is, the CPU 121 operating based on the above-described device control program cannot be activated based on the WAKEINT-P signal if it is completely stopped even in the power saving operation mode. It is necessary to operate only the circuits necessary for detecting the error and returning to the normal mode.

  In other words, even if the printer 1 is operating in the power saving operation mode, it is necessary to receive print data from the host PC 2, so that all functions cannot be stopped. Specifically, even when the printer 1 is operating in the power saving operation mode, the CPU 121, the power-off control unit 103, and the power saving control unit 104 in the sleep state need to be continuously supplied with power. In addition, since the RAM 122 and the RAM 125 are volatile memories (DRAMs), even when operating in the power saving operation mode, the stored data and programs are lost when the power supply is stopped, and the normal operation mode is restored. When doing so, time such as loading from the flash memory 120 is required. Therefore, in the printer 1, even when operating in the power saving operation mode, the self-refresh mode for the RAM 122 and RAM 125 (an operation mode in which DRAM refresh processing is periodically performed without a command from the CPU 121). It is assumed that a power supply for operating in is supplied.

  Next, the power capacity of the printer 1 will be described.

  In the example of this embodiment, it is assumed that a power source having a capacity of 50 W is adopted as the main power source 113 and a power source having a capacity of 10 W is adopted as the sub power source 111.

  When the printer 1 operates in the normal operation mode, the main power supply 113 supplies power (voltage application) to the CPU 121, RAM 122, RAM 125, printer control unit 105, image forming engine 110, and the like, and consumes about 25 W of power. To do. When the printer 1 operates in the normal operation mode, the sub power source 111 supplies power (voltage application) to the power-off control unit 103 and the power saving control unit 104 and consumes about 1 W of power. Further, when the printer 1 operates in the power saving operation mode, the main power supply 113 stops supplying power to other components. Furthermore, when the printer 1 operates in the power saving operation mode, the sub power source 111 supplies power (voltage application) to the CPU 121, RAM 122, RAM 125, the power off control unit 103, and the power saving control unit 104, and has a power of about 2W. Shall be consumed.

  Next, the internal configuration of the power supply switching circuit unit 124 will be described with reference to FIG.

  The power supply switching circuit unit 124 includes a digital transistor (hereinafter referred to as “digita”) 201, a transistor 202, a resistor 203, a resistor 204, a capacitor 205, a resistor 206, a digitala 207, a digitala 208, a resistor 209, a digitala 210, a resistor 211, A PchFET 212, a resistor 213, a capacitor 214, a resistor 215, a PchFET 216, a resistor 217, a capacitor 218, and a diode 219 are provided.

  A Powersave-N signal is input to the base terminal of the digital camera 201. The emitter terminal of the digitra 201 is connected to 0 V, which is the ground level. Further, the collector terminal of the digital circuit 201 is connected to the emitter terminal of the transistor 202 and one end of the resistor 203.

  A base terminal of the transistor 202 is connected to one end of the resistor 203. The base terminal of the transistor 202 is connected to the main power supply voltage E5V (sub power supply 111) via the resistor 204. Further, the base terminal of the transistor 202 is connected to the ground (0 V) via the capacitor 205. Furthermore, the collector terminal of the transistor 202 is connected to the sub power supply voltage E5VS (the drain terminal of the PchFET 106) via the resistor 206. In addition, the collector terminal of the transistor 202 is connected to the base terminal of the digital camera 207 and the base terminal of the digital camera 208.

  The emitter terminal of the digital camera 207 is connected to the ground (0V). The collector terminal of the digital 207 is connected to the main power supply voltage E5V (sub power supply 111) via the resistor 209. Further, the collector terminal of the digital camera 207 is also connected to the base terminal of the digital camera 210.

  The collector terminal of the digital circuit 210 is connected to the gate terminal of the PchFET 212 via the resistor 211. A resistor 213 and a capacitor 214 are connected in parallel between the gate and source of the PchFET 212. Further, the main power supply voltage E5V (sub power supply 111) is connected to the drain terminal of the PchFET 212. Furthermore, the output terminal of the power supply switching circuit unit 124 (the power supply voltage ECPU5V supplied to the CPU 121) is connected to the source terminal of the PchFET 212.

  The collector terminal of the digital transformer 208 is connected to the gate terminal of the PchFET 216 via the resistor 215. A resistor 217 and a capacitor 218 are connected in parallel between the gate and source of the PchFET 216. Further, the sub power supply voltage E5VS is connected to the source terminal of the PchFET 216. Furthermore, the anode terminal of the diode 219 is connected to the drain terminal of the PchFET 216. The output terminal of the power supply switching circuit unit 124 (power supply voltage ECPU5V supplied to the CPU 121) is connected to the cathode terminal of the diode 219.

  In the following, the base terminal portion of the digital camera 207 is referred to as “connection point P1”.

  In the printer 1, the relay circuit 112, the power-off control unit 103, the power saving control unit 104, the power supply switching circuit unit 124, and the like constitute a switching unit that performs switching control of the supply source of the power supply voltage ECPU 5V.

(A-2) Operation of the First Embodiment Next, the operation of the printer 1 of the first embodiment having the above configuration will be described.

(A-2-1) Operation from Power Off State to Transition to Normal Operation Mode First, the printer 1 is in a power off state, the power plug 101 is connected to an external AC power source, and the power is turned on (power on). The operation up to the transition to the normal operation mode will be described with reference to the flowchart of FIG. 3 and the timing chart of FIG. When each component of the printer 1 operates according to the flowchart of FIG. 3, each voltage / signal in the printer 1 (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, And the transition of the connection point P1, the power supply voltage ECPU5V) is as shown in the timing chart of FIG.

  First, assume that the user connects the power plug 101 to an outlet of an external AC power source (not shown) at timing T101 (S101).

  When the supply of AC power from the power plug 101 to the sub power supply 111 is started, the sub power supply voltage E5VS0 is output (stepped up from 0V to 5V) from the sub power supply 111 (S102). As a result, the SUBPWRON-N signal is also pulled up by the resistor 116.

  Thereafter, it is assumed that the power switch 107 is pressed (switched from the OFF state to the ON state) by the user at timing T102 (S103). As a result, the PWRSWON-N signal falls to the low level.

  When the PWRSWON-N signal becomes the Low level, the power-off control unit 103 outputs the Low level as the SUBPWRON-N signal. When SUBPWRON-N becomes low level, the PchFET 106 is turned on, and the sub power supply voltage E5VS rises (steps up from 0V to 5V). At this time, since the voltage at the connection point P1 is at a high level (sub power supply voltage E5VS = 5V), the FET 212 is turned off and the FET 216 is turned on. Thereby, the power supply switching circuit unit 124 performs switching so that the supply source of the power supply voltage ECPU5V becomes the voltage on the sub power supply voltage E5VS side. As a result, the power supply of the CPU 121 becomes the sub power supply voltage E5VS (S104). At this time, the reverse current from the sub power supply 111 side (sub power supply voltage E5VS) to the main power supply 113 side (main power supply voltage E5V) is blocked by the parasitic diode 212a of the FET 212.

  In the timing chart of FIG. 4, the power supply voltage ECPU5V using the sub power supply voltage E5VS as a supply source starts to rise from 0V at the timing T102 and reaches 5V at the timing T102-1. Then, at timing T103 after timing T102-1, the power saving control unit 104 (ADC 117) detects that the sub power supply voltage E5VS has risen (has reached 5V from 0V). When detecting the rise of the sub power supply voltage E5VS, the power saving control unit 104 (ADC 117) outputs a High level as a Powersave-N signal (S105).

  When the Powersave-N signal becomes high level at timing T103, the relay circuit 112 is turned on, the AC power supply voltage from the power plug 101 is supplied to the main power supply 113, and the main power supply 11 is activated. It is assumed that the rising of the main power supply voltage E5V output from the main power supply 113 starts (starts boosting from 0V) at the timing T104, and the base current of the transistor 202 starts to conduct at the timing T105.

  After that, the transistor 202 is turned on at the timing T106 with a delay d1 of a time constant composed of the resistor 204 and the capacitor 205, and the voltage at the connection point P1 falls to 0 V (ground level). Further, the FET 212 is turned on and the FET 216 is turned off. Thereby, in the power supply switching circuit unit 124, the supply source of the power supply voltage ECPU5V is switched to the voltage of the main power supply voltage E5V. At this time, the conduction of the diode 219 is lost, and the voltage of the ECPU 5V increases by the forward voltage of the diode 219. The diode 219 prevents the reverse current from the main power supply 113 (main power supply voltage E5V) to the sub power supply 111 side (sub power supply voltage E5VS).

  As described above, the main power supply voltage E5V is supplied to the CPU 121 (S106), and the CPU 121 is started (S107). Although the timing at which the CPU 121 is activated is not limited, for example, after a predetermined period after the power-off control unit 103 raises the Powersave-N signal to a high level (for example, a period longer than the period from timing T103 to T106) May be set in advance, and may be activated in the normal operation mode by supplying an interrupt signal (for example, an interrupt reset signal) or the like. When activated, the CPU 121 reads each program and data from the flash memory 120 and develops them in the RAM 122. Also, the control of the printer control unit 105 is started.

(A-2-2) Operation until the transition from the normal operation mode to the power saving operation mode Next, when the printer 1 is operating in the normal operation mode, the operation until the printer 1 shifts to the power saving operation mode will be described. This will be described with reference to the flowchart of FIG. 5 and the timing chart of FIG. When each component of the printer 1 operates according to the flowchart of FIG. 5, each voltage / signal in the printer 1 (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, connection point) The transition of P1 and the power supply voltage ECPU5V is as shown in the timing chart of FIG.

  First, at timing T201, the CPU 121 (device control program) generates an event for shifting to the power saving operation mode, and performs a preparation process for shifting to the power saving operation mode (S201). Although the event of shifting to the power saving operation mode in the CPU 121 is not limited, for example, there is a case where print data is not continuously supplied for a certain period or more.

  Further, as a preparation process for shifting to the power saving operation mode, the CPU 121 accesses the printer control unit 105 and confirms that there is no error in the image forming engine 110 (for example, a consumable item such as toner has run out). Note that when an error relating to an error is detected in the image forming engine 110, the CPU 121 desirably cancels the event of shifting to the power saving operation mode. If an error has occurred in the image forming engine 110, it is more convenient for the user to continue notifying the user of the error than shifting to the power saving operation mode to save power consumption. It is. At this time, the CPU 121 controls the RAM 122 and RAM 125 to operate in the self-refresh mode for data retention.

  Further, the CPU 121 performs a process for shifting to the sleep mode as a preparation process for shifting to the power saving operation mode. Specifically, the CPU 121 controls the RAM 122 to operate in the self-refresh mode in order to continue the data holding in the RAM 122. Further, the CPU 121 controls to stop the operation of the clock circuit 121c and to cut off the power supply other than the circuit corresponding to the function of accepting and returning the interrupt signal (WAKEINT-P signal or the like). Therefore, in the sleep state, the CPU 121 enters a state of waiting for an input interrupt of the return signal WAKEINT-P from the power saving control unit 104.

  When the preparation process for shifting to the power saving operation mode is completed, the CPU 121 transmits a signal indicating the completion of preparation to the printer control unit 105 (S202), and transitions to the sleep state (S203).

  When a signal indicating that the preparation process for shifting to the power saving operation mode is completed is sent from the CPU 121, the printer control unit 105 that has received the signal prepares for shifting to interrupt the power supply to the printer control unit 105 ( For example, data is saved in the RAM 125) (S204).

  Thereafter, it is assumed that the preparation process of the printer control unit 105 is completed at the timing T202. Then, the printer control unit 105 transmits a signal indicating preparation completion to the power saving control unit 104. Receiving the signal, the power saving control unit 104 outputs a Low level as a Powersave-N signal, supplies it to the power supply switching unit 124 and the relay circuit 112, and controls the main power supply 113 to be in an off state (S205).

  When the Low level Powersave-N is supplied, the power supply switching unit 124 switches the supply source of the power supply voltage ECPU5V from the main power supply voltage E5V to the sub power supply voltage E5VS (S206). In FIG. 6, the switching timing of the power supply switching unit 124 is illustrated as a timing T202-1 after the timing T202.

  Here, the time from when the CPU 121 sends a signal for preparing to shift to the power saving operation mode to the printer control unit 105 until the process for the CPU 121 to shift to the sleep state is completed is determined by using the signal from the CPU 121 as the printer control unit. It is necessary to set the power saving control unit 104 so that it is shorter than the time from when the power saving control unit 104 sends the Powersave-N signal to the power supply switching unit 124 and the relay circuit 112. That is, the CPU 121 needs to complete the transition to the sleep state before the processing timing of step S205.

  In addition, as described above, the power supply switching unit 124 switches the supply source of the power supply voltage ECPU5V from the main power supply 113 (main power supply voltage E5V) to the sub power supply 111 (sub power supply voltage E5VS), and the power supply plug 101 supplies the main power supply. The timing at which the supply of the AC voltage to 113 is interrupted by the relay circuit 112 is performed at substantially the same timing. Therefore, after the interruption by the relay circuit 112, the time until the output voltage of the main power supply 113 (main power supply voltage E5V output voltage) drops becomes longer than the switching time of the power supply switching section 124. Etc. need to be adjusted. Specifically, after the interruption by the relay circuit 112, the period until the output voltage of the main power supply 113 (main power supply voltage E5V output voltage) droops is stored in the power storage unit configured by the capacitor 113b, the capacitor 214, and the resistor 211. The delay period d2 is determined by a constant (electrical characteristic). Further, after the PchFET 216 is turned on, the falling period of the potential of the gate terminal of the PchFET 216 (the period until the voltage rises to 5 V using the sub power supply voltage E5VS as a supply source) is a constant of the capacitor 218 and the resistor 215 ( The delay period d3 is determined by the electrical characteristics. Therefore, it is necessary to set the impedance of each component in the circuit (in the power supply switching unit 124 and the main power supply 113) so that d2> d3. As a result, the power supply source is changed from the main power supply 113 to the sub power supply 111 without the voltage of the power supply voltage ECPU5V supplied to the CPU 121 being cut off or dropping below a predetermined voltage (below the lower limit of the voltage that the CPU 121 can drive). And can be switched.

  The main power supply voltage E5V starts to fall from the time T203 thereafter. At this time, the reverse current from the sub power supply voltage E5VS to the main power supply voltage E5V is blocked by the parasitic diode 212a of the FET 212 in the off state.

  As described above, the printer is in a state of operating in the power saving operation mode and in a state of low power consumption. At this time, the CPU 121 is in a low power consumption state, and the power supply to the CPU 121 operates so as to use the sub power supply voltage E5VS as a supply source by the operation of the power supply switching circuit unit 124. Is supplied with power.

(A-2-3) Operation from the power saving operation mode to the transition to the normal operation mode Next, from the state in which the printer 1 is operating in the power saving operation mode to the transition (return) to the normal operation mode The operation will be described with reference to the flowchart of FIG. 7 and the timing chart of FIG. When each component of the printer 1 operates according to the flowchart of FIG. 7, each voltage / signal in the printer 1 (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, connection point) The transition of P1 and power supply voltage ECPU5V is as shown in the timing chart of FIG.

First , it is assumed that an event for starting transition to the normal operation mode occurs when the printer 1 is operating in the power saving operation mode (S301). Here, it is assumed that when print data is supplied from the host PC 2 to the power saving control unit 104, a return event to the normal operation mode occurs.

  When the print data is supplied, the power saving control unit 104 controls the Powersave-N signal to the high level. In FIG. 8, the Powersave-N signal transitions to a high level at the timing T301.

  When the Powersave-N signal becomes High level at timing T301, the relay circuit 112 is turned on, the AC power supply voltage from the power plug 101 is supplied to the main power supply 113, and the main power supply 11 is activated. It is assumed that the main power supply voltage E5V output from the main power supply 113 starts to rise (starts boosting from 0V) at the timing T302, and the base current of the transistor 202 starts to be conductive at the timing T303.

  After that, the transistor 202 is turned on at the timing T303 with a delay d1 of a time constant composed of the resistor 204 and the capacitor 205, and the voltage at the connection point P1 falls to 0 V (ground level). Further, the FET 212 is turned on and the FET 216 is turned off. Thereby, in the power supply switching circuit unit 124, the supply source of the power supply voltage ECPU5V is switched from the sub power supply 111 (sub power supply voltage E5VS) to the main power supply 113 (main power supply voltage E5V) (S302). At this time, the conduction of the diode 219 is lost, and the voltage of the ECPU 5V increases by the forward voltage of the diode 219. The diode 219 prevents the reverse current from the main power supply 113 (main power supply voltage E5V) to the sub power supply 111 side (sub power supply voltage E5VS).

  Then, at a timing after timing T304, the power saving control unit 104 controls the return signal WAKEINT-P signal (interrupt signal) to the CPU 121 to return the CPU 121 from the sleep state to the operating state (S303). As a result, the CPU 121 and the printer control unit 105 return to the operating state according to the programs and settings stored in the RAM 122 and RAM 125 and start the printing operation. At this time, the CPU 121 is in an operating state, and the power supply voltage ECPU5V to the CPU 121 is supplied from the main power supply voltage E5V by the operation of the power supply switching circuit unit 124 and is supplied by the large-capacity main power supply 113. Become.

(A-2-4) Operation from Normal Operation Mode to Transition to Power Off State Next, the operation from the state in which the printer 1 operates in the normal operation mode to the transition to the power off state will be described with reference to FIG. It demonstrates using the flowchart of these.

  First, it is assumed that the power switch 107 is pressed by the user and the printer 1 is turned off while the printer 1 is operating in the normal operation mode. When the power switch 107 is pressed and turned off, the power-off control unit 103 transmits an OFFMODE-P signal to the power saving control unit 104 (S401).

  When the power saving control unit 104 receives the OFFMODE-P signal, the printer control unit 105 sends a signal indicating that the OFFMODE-P signal has been received to the printer control unit 105. Thereafter, the printer control unit 105 transmits a signal for preparing for power OFF (power OFF via the sleep state) to the CPU 121. When the CPU 121 receives the signal from the printer control unit 105 in the operating state, the CPU 121 starts preparation for shifting to the sleep state (S402). At this time, the preparation process when the CPU 121 shifts to the sleep state is substantially the same as that in the case of FIG. 5 described above (in the case of shifting from the normal operation mode to the power saving operation mode). However, at this time, the CPU 121 may prepare for shifting to the sleep state by ignoring an error in the image forming engine 110.

  Next, when completing preparation for shifting to the power-off state (preparation for shifting to the sleep state), the CPU 121 sends a signal indicating the completion of preparation to the printer control unit 105 and shifts to the sleep state. Upon receiving the signal, the printer control unit 105 prepares for transition to shut off the power supply (S403).

  When the preparation for shifting to the power-off state is completed, the printer control unit 105 transmits a signal indicating the completion of preparation to the power saving control unit 104. Receiving the signal, the power saving control unit 104 transmits an AUTOOFF_OK-P signal to the power off control unit 103. At this time, the power saving control unit 104 switches the supply source of the power supply voltage ECPU5V from the main power supply voltage E5V to the sub power supply voltage E5VS (in the case of FIG. 5 described above (from the normal operation mode to the power saving operation mode). (S404). Thus, the printer 1A temporarily operates once in the power saving operation mode.

  Then, the power saving control unit 104 sends a Powersave-N signal to the power supply switching unit 124 and the relay circuit 112. When receiving the AUTOOFF_OK-P signal, the power-off control unit 103 controls the PchFET 106 to cut off the power supply from the sub power source 111 to the power saving control unit 104 (S405).

  As described above, the printer 1 shifts from the normal operation mode to the power-off state. In the above-described example, when the printer 1 shifts from the normal operation mode to the power-off state, the printer 1 is controlled to operate in the power-saving operation mode (the CPU 121 operates in the sleep state), and then is in the power-off state.

(A-3) Effects of First Embodiment According to the first embodiment, the following effects can be achieved.

  The printer 1 includes a switching circuit unit 124 that switches the power supply source of the power supply voltage ECPU5V to the CPU 121 and the like to either the main power supply voltage 5V or the sub power supply voltage E5VS. Further, in the printer 1, when switching from the normal operation mode to the power saving operation mode, the CPU 121 is controlled to be in the sleep state, and then the supply from the main power supply voltage E5V is stopped when the supply source of the power supply voltage ECPU5V is used as the sub power supply. The voltage is switched to E5VS. Thus, in the printer 1, the main power supply voltage 5V having a large capacity is used as the supply source of the power supply voltage ECPU5V in the normal operation mode, and the highly efficient sub power supply voltage E5VS is supplied with the small capacity and the power supply voltage ECPU5V in the power saving operation mode. By using the power source, power supply efficiency can be improved.

(B) Second Embodiment Hereinafter, a second embodiment of an electronic apparatus and an image forming apparatus according to the present invention will be described in detail with reference to the drawings. Hereinafter, an example in which the electronic apparatus and the image forming apparatus of the present invention are applied to a printer will be described.

(B-1) Configuration of Second Embodiment FIG. 10 is a block diagram showing the overall configuration of the printer 1A of this embodiment.

  The printer 1A according to the second embodiment is different in that the power-off control unit 103 and the power supply switching circuit unit 124 are replaced with the power supply switching circuit unit 124A.

  FIG. 11 is a circuit diagram showing the internal configuration of the power supply switching circuit unit 124A.

In the configuration of the first embodiment, the switching control of the switching circuit unit 124 is configured by a transistor circuit when shifting to the normal operation mode or the power saving operation mode or when shifting from the power saving operation mode to the normal operation mode. with a constant and set the speed (timing) of the rise and fall of each power supply voltage, there is a need there problem of changing the circuit constant in accordance with the load capacity required in the printer 1A.

  For example, in the power supply switching circuit unit 124 of the first embodiment, the transistor 202 is turned on after the base current of the transistor 202 starts to conduct due to the delay d1 of the time constant formed by the resistor 204 and the capacitor 205, A period is set until the voltage at the connection point P1 falls to 0 V (ground level). However, in practice, there is a possibility that the delay d1 cannot be precisely controlled due to the individual difference of each circuit element, the use environment of the printer 1, and the like. Therefore, in the power supply switching circuit unit 124A of the second embodiment, the circuit elements (the digital circuit 201, the transistor 202, the resistor 203, the resistor 204, the capacitor 205, and the resistor 206) at the previous stage of the connection point P1 are omitted and the power-off control unit 103 Thus, a Powersave2-P signal for directly controlling the potential of the connection point P1 is input. Specifically, the Powersave2-P signal output from the power-off control unit 103 is connected to the base terminal of the digital camera 207 and the base terminal of the digital camera 208.

  Therefore, in the printer 1A, the voltage detection means for detecting the rise of the main power supply voltage E5V and the switching control means for controlling the switching timing of the power supply switching circuit section 124A are configured by the power-off control section 103 (microcomputer). ing.

  Further, since the power switching circuit unit 124A of the second embodiment does not use the digital camera 201, the PWRSWON-N signal is not input.

(B-2) Operation of the Second Embodiment Next, the difference of the operation of the printer 1A of the second embodiment having the above configuration from the first embodiment will be described. In the following, the difference between the operation of the second embodiment and the first embodiment will be described.

(B-2-1) Operation from the power-off state to the transition to the normal operation mode First, in the printer 1A, the power plug 101 is connected to the external AC power supply, turned on (power is turned on), and transitioned to the normal operation mode. The operation up to this will be described using the flowchart of FIG. 12 and the timing chart of FIG. When each component of the printer 1A operates according to the flowchart of FIG. 12, each voltage / signal in the printer 1A (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, Powersave2- The transition of the P signal (connection point P1) and the power supply voltage ECPU5V is as shown in the timing chart of FIG.

  First, assume that at time T401, the user connects the power plug 101 to an outlet of an external AC power source (not shown) (S501).

  When the supply of AC power from the power plug 101 to the sub power supply 111 is started, the sub power supply voltage E5VS0 is output (stepped up from 0V to 5V) from the sub power supply 111 (S502). As a result, the SUBPWRON-N signal is also pulled up by the resistor 116. Further, since the Powersave-N signal to the power-off control unit 103 is at a low level, the Powersave2-P signal (the voltage at the connection point P1) is output at a high level.

  After that, it is assumed that the power switch 107 is pressed (switched from the OFF state to the ON state) by the user at timing T402 (S503). As a result, the PWRSWON-N signal falls to the low level.

  When the PWRSWON-N signal becomes the Low level, the power-off control unit 103 outputs the Low level as the SUBPWRON-N signal. When SUBPWRON-N becomes low level, the PchFET 106 is turned on, and the sub power supply voltage E5VS rises (steps up from 0V to 5V). At this time, since the voltage at the connection point P1 is at a high level (sub power supply voltage E5VS = 5V), the FET 212 is turned off and the FET 216 is turned on. Thereby, the power supply switching circuit unit 124 performs switching so that the supply source of the power supply voltage ECPU5V becomes the voltage on the sub power supply voltage E5VS side. As a result, the power supply of the CPU 121 becomes the sub power supply voltage E5VS (S504).

  In the timing chart of FIG. 13, the power supply voltage ECPU5V (= sub power supply voltage E5VS) starts to rise from 0V at the timing T402 and reaches 5V at the timing T402-1. Then, at timing T403 after timing T402-1, the power-off control unit 103 (ADC 117) detects that the sub power supply voltage E5VS has risen (has reached 5V from 0V). When detecting the rise of the sub power supply voltage E5VS, the power saving control unit 104 (ADC 117) outputs a High level as a Powersave-N signal (S505).

  When the Powersave-N signal becomes High level at timing T403, the relay circuit 112 is turned on, the AC power supply voltage from the power plug 101 is supplied to the main power supply 113, and the main power supply 11 is activated. At time T404, the rising of the main power supply voltage E5V output from the main power supply 113 starts (starts boosting from 0V). After that, at time T405, the power-off control unit 103 detects that the Powersave-N signal is High and the main power supply voltage E5V has risen (has reached 5V), so that the Powersave2-P signal is output Low. Transition to. As a result, the FET 212 is turned on and the FET 216 is turned off. Thereby, the supply source of the power supply voltage ECPU5V is switched to the main power supply voltage E5V.

  As described above, the CPU 121 is supplied with a voltage using the main power supply voltage E5V as a power source (S506), and is activated (S507).

(B-2-2) Operation until transition from the normal operation mode to the power saving operation mode Next, when the printer 1A is operating in the normal operation mode, the operation until the transition to the power saving operation mode is performed. This will be described with reference to the flowchart of FIG. 14 and the timing chart of FIG. When each component of the printer 1A operates according to the flowchart of FIG. 14, each voltage / signal in the printer 1A (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, Powersave2- The transition of the P signal (connection point P1) and the power supply voltage ECPU5V is as shown in the timing chart of FIG.

  First, it is assumed that at time T501, the CPU 121 (apparatus control program) generates an event for shifting to the power saving operation mode and performs a preparation process for shifting to the power saving operation mode (S601).

  When the preparation process for shifting to the power saving operation mode is completed, the CPU 121 transmits a signal indicating the completion of preparation to the printer control unit 105 (S602), and transitions to the sleep state (S603).

  When a signal indicating that the preparation process for shifting to the power saving operation mode is completed is sent from the CPU 121, the printer control unit 105 that has received the signal prepares for shifting to interrupt the power supply to the printer control unit 105 ( For example, data is saved in the RAM 125) (S604).

  Thereafter, it is assumed that the preparation process of the printer control unit 105 is completed at the timing T202. Then, the printer control unit 105 transmits a signal indicating preparation completion to the power saving control unit 104. Receiving the signal, the power saving control unit 104 outputs a Low level as a Powersave-N signal, supplies it to the power supply switching unit 124A and the relay circuit 112, and controls the main power supply 113 to be turned off (S605).

  Then, the power-off control unit 103 outputs the Powersave2-P signal as a Low level when it detects the Low level of the Powersave-N signal. Thereby, in the power supply switching unit 124A, the FET 212 is turned off and the FET 216 is turned on, and the supply source of the power supply voltage ECPU5V is switched from the main power supply voltage E5V to the sub power supply voltage E5VS (S606). In FIG. 15, the switching timing of the power supply switching unit 124A is illustrated as a timing T502-1 after the timing T502.

  As in the first embodiment, the time from when the CPU 121 sends a preparation completion signal for transition to the power saving operation mode to the printer control unit 105 until the process for the CPU 121 to transition to the sleep state is completed is as follows. It is necessary to set a time shorter than the time from when the printer control unit 105 receives a signal from the CPU 121 to when the power saving control unit 104 sends the Powersave-N signal to the power supply switching unit 124A and the relay circuit 112. In the second embodiment, the time until the output voltage of the main power supply 113 (main power supply voltage E5V output voltage) drops after the interruption by the relay circuit 112 is the same as in the first embodiment described above. The power supply switching unit 124A and the like are adjusted so as to be longer than the switching time of the switching unit 124A.

  Thus, the printer 1A is in a state of operating in the power saving operation mode, and is in a low power consumption state.

(B-2-3) Operation from the power saving operation mode to the transition to the normal operation mode Next, from the state in which the printer 1A is operating in the power saving operation mode to the transition (return) to the normal operation mode The operation will be described with reference to the flowchart of FIG. 16 and the timing chart of FIG. When each component of the printer 1A operates according to the flowchart of FIG. 16, each voltage / signal (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, Powersave2- The transition of the P signal (connection point P1) and the power supply voltage ECPU5V is as shown in the timing chart of FIG.

  First. It is assumed that an event for starting transition to the normal operation mode occurs when the printer 1A is operating in the power saving operation mode (S701). Here, as in the first embodiment, it is assumed that a return event to the normal operation mode occurs when print data is supplied from the host PC 2 to the power saving control unit 104.

  When the print data is supplied, the power saving control unit 104 controls the Powersave-N signal to the high level. In FIG. 16, the Powersave-N signal transitions to a high level at timing T601.

  When the Powersave-N signal becomes High level at timing T601, the relay circuit 112 is turned on, the AC power supply voltage from the power plug 101 is supplied to the main power supply 113, and the main power supply 11 is activated. Then, at timing T602, the rising of the main power supply voltage E5V output from the main power supply 113 starts (starts boosting from 0V).

  In the timing chart of FIG. 17, the power supply voltage ECPU5V (= sub power supply voltage E5VS) starts to rise from 0V at the timing T602 and reaches 5V at the timing T602-1. Assume that at time T603 after timing T602-1, the power-off control unit 103 (ADC 117) detects that the Powersave-N signal is at a high level and the rising of the main power supply voltage E5V. In this case, the power-off control unit 103 outputs a Low level as a Powersave2-P signal. As a result, the FET 212 is turned on and the FET 216 is turned off, and the supply source of the power supply voltage ECPU5V is switched to the main power supply voltage E5V (S702). At this time, the conduction of the diode 219 is lost, and the voltage of the power supply voltage ECPU5V increases by the forward voltage of the diode 219. At this time, the diode 219 prevents the reverse flow from the main power supply voltage E5V to the sub power supply voltage E5VS.

  Then, at a timing after timing T603, the power saving control unit 104 controls the return signal WAKEINT-P signal (interrupt signal) to the CPU 121 to return the CPU 121 from the sleep state to the operating state (S703). As a result, the CPU 121 and the printer control unit 105 return to the operating state according to the programs and settings stored in the RAM 122 and RAM 125 and start the printing operation.

(B-2-4) Operation from normal operation mode to transition to power-off state Operation from printer 1A according to the second embodiment operating in normal operation mode to transition to power-off state Is the same as that of the first embodiment except that the process at the time of shifting to the power saving operation mode is different (the process of FIG. 14 described above is applied), and thus detailed description thereof is omitted.

(B-3) Effects of Second Embodiment According to the second embodiment, the following effects can be obtained in addition to the effects of the first embodiment.

  As described above, the power supply switching circuit unit 124A of the printer 1A of the second embodiment omits the circuit elements (the digital circuit 201, the transistor 202, the resistor 203, the resistor 204, the capacitor 205, and the resistor 206) at the previous stage of the connection point P1, A power save 2-P signal for directly controlling the potential of the connection point P1 is input from the power-off control unit 103. The rise of the main power supply voltage E5V is detected by the ADC 117 of the power-off control unit 103, and the switching timing of the power supply switching circuit unit 124A is controlled by the power-off control unit 103 (Powersave2-P). As a result, the printer 1A can detect the rise of the main power supply voltage E5V (detect that the voltage has reached a predetermined value) and accurately execute the timing for switching the power supply switching circuit unit 124A. In the first embodiment, the circuit elements (the digital transistor 201, the transistor 202, the resistor 203, the resistor 204, the capacitor 205, and the resistor 206) in the previous stage of the connection point P1 are configured by discrete elements, but the second embodiment Then, since only the power-off control unit 103 (microcomputer) can perform the functions of the above-described circuit elements, the above-described control can be performed with higher accuracy than in the first embodiment. In general, a microcomputer constituted by one semiconductor chip can perform signal processing and voltage detection with higher accuracy than a circuit constituted on a substrate by combining discrete elements.

(C) Third Embodiment Hereinafter, a third embodiment of an electronic apparatus and an image forming apparatus according to the present invention will be described in detail with reference to the drawings. Hereinafter, an example in which the electronic apparatus and the image forming apparatus of the present invention are applied to a printer will be described.

(C-1) Configuration of the Third Embodiment FIG. 18 is a block diagram showing the overall configuration of the printer 1B of this embodiment. The same or corresponding parts as those in FIG. 10 of the second embodiment are the same. Or the corresponding code | symbol is attached | subjected.

  Hereinafter, differences of the third embodiment from the second embodiment will be described.

  The printer 1 of the second embodiment corresponds to one power saving operation mode, but the third embodiment is different from the second embodiment in that it corresponds to a plurality of power saving operation modes. Is different. Hereinafter, the printer 1B corresponds to the second power saving operation mode in addition to the power saving operation mode (hereinafter referred to as “first power saving operation mode”) similar to that of the second embodiment. Shall. When the printer 1B operates in the second power saving operation mode, the main power supply 113 is not turned off (the relay circuit 112 is turned off), and only the CPU 121 is shifted to the sleep state to wait for the print data from the host PC 2. Shall be.

  Specifically, in the printer 1B, the CPU 121 or the power saving control unit 104 outputs a Powersave3-N signal that notifies the transition to the second power saving operation mode, and the Powersave3-N signal is a power-off control unit. 103 is input.

  Although the timing at which the CPU 121 (device control program) determines to shift to the first power saving operation mode or the second power saving operation mode is not limited, for example, the power saving operation to be shifted according to the setting by the user The mode may be determined.

(C-2) Operation of Third Embodiment Next, the difference of the operation of the printer 1B of the third embodiment having the above configuration from the second embodiment will be described. Since the operation of the printer 1B of the third embodiment is different from that of the second embodiment only in the portion related to the second power saving operation mode, only the operation relating to the second power saving operation mode will be described below. Description of the operation related to the first power saving operation mode is omitted.

(C-2-1) Operation from Transition from Normal Operation Mode to Second Power Saving Operation Mode Next, when printer 1B is operating in normal operation mode, transition to second power saving operation mode The operation up to this will be described with reference to the flowchart of FIG. 19 and the timing chart of FIG. When each component of the printer 1B operates according to the flowchart of FIG. 19, each voltage / signal (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, Powersave3- The transition of the N signal, Powersave2-P signal (connection point P1), and power supply voltage ECPU5V) is as shown in the timing chart of FIG.

  First, at timing T701, the CPU 121 (device control program) generates an event for shifting to the second power saving operation mode, and performs a preparation process for shifting to the second power saving operation mode ( S801).

In the second power saving operation mode, the power supply to the printer control unit 105 is not shut down. In this case, the CPU 121 omits the process for the printer control unit 105 as a preparation process for shifting to the second power saving operation mode. and, CPU 121, RAM 122, and may be performed only processing relating to RAM 125. However, in this case, as a preparation process for shifting to the second power saving operation mode, the CPU 121 causes the printer control unit 105 to operate each mechanism (illustrated) so that the printer control unit 105 operates with less power consumption than in the normal operation mode. In the following description, it is instructed to stop the driving of the motor and the like not to be performed.

  The CPU 121 outputs a Low level as a Powersave3-N signal when entering the sleep state by the preparation process for shifting to the second power saving operation mode (S802).

  The power-off control unit 103 detects the Powersave2-P signal when the main power supply voltage E5V is raised (5V state), the Powersave-N signal is at a high level, and the Powersave3-N signal is at a low level. Output at High level. As a result, the FET 212 is turned off and the FET 216 is turned on, and the supply source of the power supply voltage ECPU5V is switched from the main power supply voltage E5V to the sub power supply voltage E5VS (S803). At this time, since the parasitic diode F212a of the FET 212 in the off state has a larger VF than the diode 219, no current flows from 5V to the ECPU 5V.

  Thereafter, the CPU 121 enters a sleep state, and the printer 1B operates in the second power saving operation mode.

(C-2-2) Operation from the second power saving operation mode to the transition to the normal operation mode Next, when the printer 1B is operating in the second power saving operation mode, the mode is changed to the normal operation mode. (return) describes the operations until you will be described with reference the flowchart of FIG. 21, and the timing chart of FIG 22. When each component of the printer 1B operates according to the flowchart of FIG. 21, each voltage / signal in the printer 1B (sub power supply voltage E5VS0, SUBPWRON-N signal, sub power supply voltage E5VS, Powersave-N signal, main power supply voltage E5V, Powersave3- The transition of the N signal, Powersave2-P signal (connection point P1), and power supply voltage ECPU5V) is as shown in the timing chart of FIG.

  First, it is assumed that when the printer 1B is operating in the second power saving operation mode, an event for starting the transition to the normal operation mode occurs at timing T801 (S901).

  Here, as in the second embodiment, when print data is supplied from the host PC 2 to the power saving control unit 104, it is assumed that a return event to the normal operation mode occurs. Even in the second power saving operation mode, when print data is supplied from the host PC 2 to the power saving control unit 104, the power saving control unit 104 outputs a High level as a Powersave3-N signal. As a result, the power-off control unit 103 detects that the main power supply voltage E5V has risen (5V state), the Powersave-N signal is at a high level, and the Powersave3-N signal is at a high level. A Low level is output as a Powersave2-P signal. As a result, the FET 212 is turned on and the FET 216 is turned off, and the supply source of the power supply voltage ECPU5V is switched from the sub power supply voltage E5VS to the main power supply voltage E5V (S902).

  Then, at a timing after the supply source of the power supply voltage ECPU5V is switched to the main power supply voltage E5V (for example, a timing after a predetermined period from the timing T801), the power saving control unit 104 returns a return signal WAKEINT-P signal ( The CPU 121 is returned from the sleep state to the operating state by controlling the interrupt signal (S903). As a result, the CPU 121 and the printer control unit 105 return to the operating state according to the programs and settings stored in the RAM 122 and RAM 125 and start the printing operation. In addition, after returning to the operating state, the CPU 121 instructs the printer control unit 105 to return the image forming engine 110 to the normal state (instruction to cancel the power saving state).

(C-3) Effects of Third Embodiment According to the third embodiment, the following effects can be obtained in addition to the effects of the second embodiment.

  In the third embodiment, since the second power saving operation mode is provided in addition to the first power saving operation mode, more flexible power saving control is performed compared to the second embodiment, User convenience can be improved. When the printer 1B enters the second power saving operation mode, the main power supply 113 is not turned off (the relay circuit 112 is turned off), and the power supply to other components (the printer control unit 105, etc.) is not shut off. Thus, it is possible to return to the normal operation mode in a shorter time.

(D) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(D-1) In each of the above embodiments, the example in which the electronic device of the present invention is applied to a printer has been described. However, the present invention may be applied to other electronic devices. For example, (a component according to the function of the electronic device, in the embodiments of the image forming engine falls) the body portion comprises a, one or more control unit according to the control of the body portion, the power-saving The present invention can be applied to the same effect as long as it is an electronic device that cannot stop power supply to all the control units even when operating in the operation mode. In each of the above-described embodiments, an example in which the image forming apparatus of the present invention is applied to a printer has been described. However, the image forming apparatus of the present invention may be replaced with another image forming apparatus (for example, a FAX, a copier, a multifunction machine, etc.). ) May be applied.

(D-2) In the third embodiment, the printer 1B adds a configuration for supporting the second power saving operation mode to the printer 1A of the second embodiment. The printer 1 may also be adapted to the second power saving operation mode.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 101 ... Power plug, 102 ... Low voltage power supply, 103 ... Power-off control part, 104 ... Power saving control part, 105 ... Printer control part, 106 ... PchFET, 107 ... Power switch, 109 ... DC / DC converter, DESCRIPTION OF SYMBOLS 110 ... Image forming engine, 111 ... Sub power supply, 112 ... Relay circuit, 113 ... Main power supply, 113a ... Capacitor, 113b ... Capacitor, 114 ... Resistance, 115 ... High voltage power supply, 116 ... Resistance, 117 ... ADC, 118 ... Resistance, DESCRIPTION OF SYMBOLS 119 ... High voltage power supply, 120 ... Flash memory, 121 ... CPU, 121a ... Communication circuit, 121b ... Communication circuit, 121c ... Clock circuit, 122 ... RAM, 123 ... DC / DC converter, 124 ... Power supply switching circuit unit, 125 ... RAM 201 ... Digitra, 202 ... Transistor, 203 ... Resistance, 04 ... resistor, 205 ... capacitor, 206 ... resistor, 207 ... digital trait, 208 ... digital trait, 209 ... resistor, 210 ... digital trait, 211 ... resistor, 212 ... PchFET, 213 ... resistor, 214 ... capacitor, 215 ... resistor, 216 ... PchFET, 217 ... resistor, 218 ... capacitor, 219 ... diode.

Claims (6)

A first voltage supply unit; a second voltage supply unit having a smaller capacity than the first voltage supply unit;
A main body having a configuration related to the function of the electronic device;
A control unit that performs control processing according to the main body unit, and that is driven by a voltage using the first voltage supply unit or the second voltage supply unit as a supply source;
A switching unit that switches a supply source of a voltage to be applied to the control unit to either the first voltage supply unit or the second voltage supply unit;
The control unit can operate in either a first operation state that operates with a predetermined power consumption or a second operation state that operates with a power consumption lower than the first operation state. Yes,
The switching unit switches a supply source of a voltage to be applied to the control unit to the second voltage supply unit when the control unit shifts to the second operation state, and the control unit When shifting to the operating state, the supply source of the voltage applied to the control unit is switched to the first voltage supply unit,
A power storage unit that stores electric power based on a voltage applied to the switching unit from the second voltage supply unit;
The switching unit cuts off the voltage supply from the first voltage supply unit when the voltage supply source to be applied to the control unit is switched from the first voltage supply unit to the second voltage supply unit. After that, voltage application to the control unit using the second voltage supply unit as a supply source is started,
The switching unit applies a voltage using the power stored in the power storage unit as a supply source to the control unit after the voltage supply from the first voltage supply unit is interrupted. machine.   When the control unit transitions from the first operation state to the second operation state, the switching unit transitions to a state in which the control unit operates in the first operation state. The electronic device according to claim 1, wherein a supply source of a voltage to be applied to is switched from the first voltage supply unit to the second voltage supply unit.   The power storage unit has a voltage applied to the control unit using the second voltage supply unit as a supply source after the voltage supply from the first voltage supply unit is interrupted at least by the switching unit. 3. The electronic device according to claim 1, wherein the electronic device is configured by an electric circuit having an electrical characteristic that a voltage applied to the control unit does not drop until the voltage is increased to a predetermined value. When the switching unit switches the voltage supply source to be applied to the control unit from the second voltage supply unit to the first voltage supply unit, the voltage supply from the first voltage supply unit is resumed. Voltage detecting means for detecting that the voltage applied from the first voltage supply unit to the switching unit has increased to a predetermined value;
After the voltage detection means detects that the voltage applied from the first voltage supply unit to the switching unit has risen to a predetermined value, a supply source of the voltage applied to the control unit is set to the second The electronic device according to claim 1, further comprising: a switching control unit that controls the switching unit so as to switch from the voltage supply unit to the first voltage supply unit.   The electronic apparatus according to claim 4, wherein the voltage detection unit and the switching control unit are configured using a microcomputer. A first voltage supply unit; a second voltage supply unit having a smaller capacity than the first voltage supply unit;
An image forming unit for performing an image forming process on a medium;
A control unit that performs control processing related to the image forming unit, and that is driven by a voltage using the first voltage supply unit or the second voltage supply unit as a supply source;
A switching unit that switches a supply source of a voltage to be applied to the control unit to either the first voltage supply unit or the second voltage supply unit;
The control unit can operate in either a first operation state that operates with a predetermined power consumption or a second operation state that operates with a power consumption lower than the first operation state. Yes,
The switching unit switches a supply source of a voltage to be applied to the control unit to the second voltage supply unit when the control unit shifts to the second operation state, and the control unit When shifting to the operating state, the supply source of the voltage applied to the control unit is switched to the first voltage supply unit,
A power storage unit that stores electric power based on a voltage applied to the switching unit from the second voltage supply unit;
The switching unit cuts off the voltage supply from the first voltage supply unit when the voltage supply source to be applied to the control unit is switched from the first voltage supply unit to the second voltage supply unit. After that, voltage application to the control unit using the second voltage supply unit as a supply source is started,
The switching unit applies a voltage using a power stored in the power storage unit as a supply source to the control unit after the voltage supply from the first voltage supply unit is cut off. Forming equipment.

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