Sub power source-type electronic device and image forming apparatus

An electronic device includes a first voltage output part configured to output a first voltage, a second voltage output part configured to output a second voltage, a first controller configured to receive the first voltage supplied from the first voltage output part, a second controller configured to receive the first voltage supplied from the first voltage output part, and a third controller configured to receive the second voltage supplied from the second voltage output part. The first controller stops the supply of the first voltage to the second controller by the first voltage output part after the supply of the second voltage to the third controller by the second voltage output part has been stopped.

CROSS REFERENCE TO RELATED APPLICATION

The present application is related to, claims priority from and incorporates by reference Japanese Patent Application No. 2011-283131, filed on Dec. 26, 2011.

TECHNICAL FIELD

The present invention relates to an electronic device with a sub power source type power source for power-saving and an image forming apparatus.

BACKGROUND

Conventionally, for the sake of power-saving in an electronic device such as a personal computer and the like, a sub power source type electronic device is known in which a main voltage is supplied from a main power source during operation of the electronic device. The main power source is turned off and a small amount of sub voltage is supplied by a sub power source when the electronic device does not constantly operate for a certain period of time (JP Patent No. 2,997,584).

However, in the above conventional electronic device with the sub power source type power source for power-saving, there is a problem that a power circuit becomes complicated in a case where an auto power-off function is added that automatically switches a current-application state to the apparatus. Therefore, it is desired to add the auto power-off function with a simple configuration to such an electronic device with the sub power source and the main power source.

SUMMARY

Considering the above desire, an electronic device disclosed in the application includes a first voltage output part configured to output a first voltage, a second voltage output part configured to output a second voltage, a first controller configured to receive the first voltage supplied from the first voltage output part, a second controller configured to receive the first voltage supplied from the first voltage output part, and a third controller configured to receive the second voltage supplied from the second voltage output part. The first controller stops the supply of the first voltage to the second controller by the first voltage output part after the supply of the second voltage to the third controller by the second voltage output part has been stopped.

In another view of the invention, an electronic device disclosed in the application includes an first voltage output part configured to convert a power source voltage to a first device voltage, a first controller configured to be operable upon receiving the first voltage, a second controller in communication with the first controller and configured to be operable upon receiving the first voltage, a second voltage output part configured to convert the power source voltage to a second voltage, and a third controller configured to be operable upon receiving the second voltage and to control an ON mode. The first controller and the second controller together configured to control an OFF mode and a deep sleep mode, and being configured to stop the first voltage output by the first voltage output part to the second controller after the second controller stops the second voltage output to the third controller.

According to the electronic device of the present invention, the first controller stops the first voltage supplied to the second controller by the first voltage output part after the second voltage supplied to the third controller by the second voltage output part has been stopped. Therefore, there is an effect in which the auto power-off function is realized with the simple configuration.

DESCRIPTION OF EMBODIMENTS

The electronic device and the image forming apparatus will become more readily understood when read in light of the explanation of preferred embodiments and accompanying drawings. However, the drawings are for explanation purposes only and are not intended to limit the scope of the invention.

(Configuration of First Embodiment)

FIG. 1is a schematic circuit view of an electronic device (e.g. printer)1according to a first embodiment of the present invention.

The printer1includes a constant voltage power source10that converts an alternating current (hereinafter referred to as “AC”) voltage90asupplied from an AC power source90to a direct current (hereinafter referred to as “DC”) voltage and that supplies the voltage, a first controller (e.g. power-off control part)20that controls an auto power-off of the power source, a second controller (e.g. power-saving control part)30that cooperates with the power-off control part20to perform a power-saving control, a third controller (e.g. printer control part)40to which predetermined voltages are supplied from the constant voltage power source10and which controls various circuits and various functional parts that are various mechanisms of the printer1(not shown). The printer control part40includes a hard disk drive (hereinafter referred to as “HDD”)41that is a nonvolatile memory that stores various control information and the like.

The printer control part40is a controller that controls an image forming part that forms a toner image, a transfer part that transfers the toner image formed in the image forming part, a fuser part that fixes the toner image transferred on a medium, and carrying part that carries the medium and the like (not shown), and is a main controller to which a main voltage converted by a main analog-to-digital (AC/DC) converter circuit12is supplied.

The constant voltage power source10includes a first voltage output part (e.g. sub AC/DC converter circuit)11that converts the AC voltage90ato first voltages (e.g. a 3.3V sub voltage) that are DC voltages and outputs the first voltages to a signal line11a, a second voltage output part (e.g. main AC/DC converter circuit)12to which AC voltage90ais supplied from the AC power source90through a second supply part (e. g relay circuit)13, and which converts the voltage to second voltages (e.g. main 24V and 5V voltages) that are DC voltages, and which supplies to the printer control part40through the signal lines12aand12b. The signal line12bbranches and is connected to a DC/DC converter5. The DC/DC converter5converts the 5V main voltage to the 3.3V main voltage, and supplies the voltage to the printer control part40thorough the signal line12c.

The signal line11aconnected to the sub AC/DC converter circuit11is connected to a source of a P channel field-effect transistor (hereinafter referred to as “PchFET”)2that is a first supply part, and to a gate of the PchFET2through a resistor R3. The gate of the PchFET2is connected to the power-off control part20. A drain of the PchFET2is connected to the power-saving control part30and an analog-digital converter (hereinafter referred to as “ADC”)21as an input part of the power-off control part20.

Here, expressions of the sub voltages and the main voltages are defined as described below. The 3.3V sub voltage that the sub AC/DC converter circuit11outputs to the signal line11ais expressed as sub voltage 3.3VS0. The 3.3V sub voltage input from the signal line11ato the power-saving control part30is expressed as sub voltage 3.3VS. The 24V and 5V main voltages are expressed as main voltages 24V and 5V. The 3.3V main voltage is expressed as main voltage 3.3V.

The power-off control part20is a controller of which consumed power is smaller than that of the power-saving control part30, and a sub control part to which the sub voltage converted by the sub AC/DC converter circuit11is supplied.

The power-off control part20includes the ADC21that detects a change of voltage, a sending part22that outputs a request signal OFFMODE-P to the signal line20athat is a first notification part, and a receiving part23that receives a permission signal AUTOOFF_OK-P through the signal line20bthat is a first instruction part. The request signal OFFMODE-P is a signal that requests stoppage of the main voltages and is an output specification of an open drain that is pulled up to 3.3VS by a resistor R4.

The power-off control part20outputs a first switching signal SUBPWRON-N to the gate of the PchFET2. The first switching signal SUBPWRON-N is an output specification of an open drain that is pulled up to 3.3VS0 by the resistor R3. The sub voltage 3.3VS0 is input to the source of the PchFET2. The PchFET2is switched to one of two current-application states including an output state in which the input sub voltage 3.3VS0 is output as the sub voltage 3.3VS or a stop state in which the output of the sub voltage 3.3VS0 is stopped based on the first switching signal SUBPWRON-N.

When the first switching signal SUBPWRON-N is at low level (hereinafter referred to as “L”), the current-application state of the PchFET2is configured to be the output state (ON state). When the SUBPWRON-N is at high level (hereinafter referred to as “H”), the current-application state of the PchFET2is configured to be the stop state (OFF state).

One end of the power-off control part20is connected to an other end of the power source switch3that is connected to ground (GND). The other end of the power source switch3is connected to a resistor R1connected to the signal line11a, and is pulled up to 3.3VS0. When the power source switch3is depressed, a control signal CONT “L” is input from the power source switch3to the power-off control part20, and in a state in which the power source switch3is not depressed, the control signal CONT “H” is input from the power source switch3to the power-off control part20.

The power-off control part20is connected to an anode of a power source switch LED4that is a lamp with a light emitting diode (hereinafter referred to as “LED”) through a resistor R2. A cathode of the power source switch LED4is connected to ground GND. When the power-off control part20outputs a signal “H”, the power source switch LED4is turned on. When the power-off control part20outputs a signal “L,” the power source switch LED4is turned off.

The power-saving control part30includes a timer31that clocks time, a receiving part32that inputs the request signal OFFMODE-P, and a sending part33that sends the permission signal AUTOOFF13OK-P that permits stoppage of the sub voltage 3.3VS0.

The power-saving control part30is a controller of which consumed power is smaller than that of the printer control part40, and a sub controller to which the sub voltage is converted by the sub AC/DC converter circuit11is supplied.

The power-saving control part30is connected to a host personal computer (hereinafter referred to as “host PC”)91that is a host computer. The power-saving control part30receives print job data from the host PC91, converts the print job data into image data, and outputs the printer control part40. The printer control part40outputs a state notification signal STATUS that notifies various states to the power-saving control part30through the signal line20c.

A signal (second switching signal POWERSAVE-N) is input to an input part24of the power-off control part20through a signal line B that branches between the power-saving control part30and the relay circuit13from the signal line30a. An output state of the main voltage 3.3V is input to the ADC21as the input part through a signal line A that branches between the DC/DC converter5and the printer control part40from the signal line12c. An output state of the sub voltage 3.3VS is input to the ADC21through a signal line C that branches between the PchFET2and the power-saving control part30.

The power-saving control part30outputs the second switching signal POWERSAVE-N to the relay circuit13and the power-off control part20through the signal line30a. When the second switching signal POWERSAVE-N is “H,” the relay circuit13is turned on and the AC voltage90ais input to the main AC/DC converter circuit12. When the second switching signal POWERSAVE-N is “L,” the relay circuit13is turned off and the AC voltage90ais stopped.

(Operation of First Embodiment)

Regarding supply states of power, the printer1includes four basic apparatus states such as an AC OFF state, an OFF mode, an ON mode and a deep sleep mode. The AC OFF state is an apparatus state in which the AC power is not supplied. The OFF mode is an apparatus state in which the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40, and supply of the sub voltage 3.3VS to the power-saving control part30is stopped, and only the sub voltage 3.3VS0 is supplied to the power-off control part20.

The ON mode is an apparatus state in which the main voltages 24V, 5V and the main voltage 3.3V is supplied to the printer control part40and the sub voltage 3.3VS is supplied to the power-saving control part30; moreover, the sub voltage 3.3VS0 is supplied to the power-off control part20. In the ON mode, the printer1immediately operates when the printer1receives the print job data.

The deep sleep mode is an apparatus state in which the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40is stopped, and the sub voltage 3.3VS is supplied to the power-saving control part30. Moreover, the sub voltage 3.3VS0 is supplied to the power-off control part20. In the ON mode, in the case when job is not received for a predetermined time period (e.g. 15 minutes), the power-saving control part30shifts the apparatus state to the deep sleep mode. In the deep sleep mode, when a reset condition from the deep sleep mode to the ON mode is ready, the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40is resumed by the control of the power-saving control part30, and the printer1operates. The reset condition includes the depression of the power source switch3by a user and receipt of the print job data from the host PC91, for example.

FIG. 2is a state transition diagram of an operation of the power-off control part20inFIG. 1. The power-off control part20shifts the apparatus state to an OFF mode P1when the sub voltage 3.3VS0 is fed from the sub AC/DC converter circuit11.

In the OFF mode P1, the power-off control part20turns off the power source switch LED4, and outputs the request signal OFFMODE-P signal “H,” and outputs the first switching signal SUBPWRON-N “H.” As a result, the PchFET2is turned off. The power-off control part20transitions the apparatus state to an ON mode transition P2by detecting the depression of the power source switch3. In the OFF mode, the depression of the power source switch3is detected since the sub voltage 3.3VS0 is supplied to the power-off control part20.

In the ON mode transition P2, the power-off control part20turns on the power source switch LED4, outputs the request signal OFFMODE-P “L,” and outputs the first switching signal SUBPWRON-N “L.” As a result, the PchFET2is turned on and the sub voltage 3.3VS is supplied to the power-saving control part30. The ADC21of the power-off control part20detects the supply of the sub voltage 3.3VS, and transitions the apparatus state to an ON mode P3. In the ON mode transition P2, the ADC21causes the apparatus state to transition to a time-out error P8in the case when the supply of the sub voltage 3.3VS is not detected for two seconds.

In the ON mode P3, the power-off control part20turns on the power source switch LED4, outputs the request signal OFFMODE-P “L,” and outputs the first switching signal SUBPWRON-N “L.”

In the ON mode P3, the power-off control part20transitions the apparatus state to an OFF mode transition1P4by detecting the depression of the power source switch3with the control signal CONT. In the OFF mode transition1P4, the power-off control part20transitions the apparatus state to an OFF mode transition2P5when the power-off control part20detects the permission signal AUTOOFFOK13OK-P “H” that permits stoppage of the sub voltage 3.3VS0.

In the OFF mode transition1P4, the power-off control part20turns on and off the power source switch LED4at a low frequency of 1 Hz. The power-off control part20outputs the request signal OFFMODE-P “H,” and outputs the first switching signal SUBPWRON-N “L.” In the OFF mode transition1P4, the power-off control part20transitions the apparatus state to the OFF mode transition2P5by detecting the permission signal AUTOOFF_OK-P “H” that permits stoppage of the sub voltage 3.3VS0.

In the OFF mode transition2P5, the power-off control part20turns on and off the power source switch LED4at a low frequency of 1 Hz. The power-off control part20outputs the request signal OFFMODE-P “H,” and outputs the first switching signal SUBPWRON-N “L.” In the OFF mode transition2P5, the power-off control part20transitions the apparatus state to an OFF mode transition3P6by detecting the second switching signal POWERSAVE-N “L.” In the OFF mode transition2P5, the power-off control part20causes the apparatus state to transition to the time-out error P8in the case when the second switching signal POWERSAVE-N “L” is not detected for five seconds.

In the OFF mode transition3P6, the power-off control part20turns on and off the power source switch LED4at a low frequency of 1 Hz. The power-off control part20outputs the request signal OFFMODE-P “H,” and outputs the first switching signal SUBPWRON-N “L.” The ADC21of the power-off control part20detects stoppage of the main voltage 3.3V, and transitions the apparatus state to an OFF mode transition4P7. The power-off control part20causes the apparatus state to transition to the time-out error P8in the case when stoppage of the main voltage 3.3V is not detected for two seconds.

In the OFF mode transition4P7, the power-off control part20turns on and off the power source switch LED4at a low frequency of 1 Hz. The power-off control part20outputs the request signal OFFMODE-P “H,” and outputs the first switching signal SUBPWRON-N “H.” The power-off control part20transitions the apparatus state to the OFF mode P1by detecting stoppage of the sub voltage 3.3VS. The power-off control part20causes the apparatus state to transition to the time-out error P8in the case when stoppage of the sub voltage 3.3VS is not detected for two seconds.

In the time-out error P8, the power-off control part20turns on and off the power source switch LED4at a high frequency of 3 Hz. The power-off control part20outputs the request signal OFFMODE-P “H,” and outputs the first switching signal SUBPWRON-N “H.” The power-off control part20includes a mandatory off mode shift function, and preferentially causes the apparatus state to transition to the the OFF mode transition4P7in the case when a continuous five-minute ON state, in which the power source switch3is depressed for a long time, is detected.

FIG. 3is a flow diagram of an operation of the power-saving control part30inFIG. 1. In S1, the power-saving control part30sets a value of an OFF mode timer of the OFF mode to6hours, starts to clock time with the timer31, and shifts to S2. In S2, the power-saving control part30selects a value of a deep sleep mode timer of the deep sleep mode to 15 minutes, starts to clock time with the timer31, and shifts to S3.

In S3, the power-saving control part30outputs the second switching signal POWERSAVE-N “H.” As a result, the relay circuit13is turned on, and the main voltages 24V, 5V and the main voltage 3.3V are supplied to the printer control part40. The power-saving control part30shifts to S4. In S4, the power-saving control part30performs the detection of the request signal OFFMODE-P. Stoppage of the main voltages 24V, 5V and the main voltage 3.3V is requested in the case when the request signal OFFMODE-P is “H.” The power-saving control part30shifts to S13. The power-saving control part30shifts to S5in the case when the request signal OFFMODE-P is “L.”

In S5, the power-saving control part30judges whether or not the OFF mode timer has counted six hours, which is an auto-off condition. The power-saving control part30shifts to S13in the case when the OFF mode timer has counted six hours. The power-saving control part30shifts to S6in the case when the OFF mode timer has not counted six hours.

In S6, the printer control part40judges whether or not the printer1is currently in the deep sleep mode. The printer control part40shifts to S10in the case when the printer1is in the deep sleep mode. The printer control part40shifts to S7in the case when the printer1is not in the deep sleep mode. In S7, the printer control part40judges whether or not a shift condition to the deep sleep mode have been satisfied; that is, the deep sleep mode timer has counted 15 minutes. The printer control part40shifts to S8in the case when the deep sleep mode timer has counted 15 minutes. The printer control part40returns to S4in the case when the deep sleep mode timer has not counted15minutes.

In S8, the power-saving control part30instructs the printer control part40to perform a shutdown process with an instruction signal DRCT. The printer control part40performs the shutdown process to shunt control parameters and the like to the HDD41that is a nonvolatile memory, and notifies the power-saving control part30of the completion of the shutdown with the state notification signal STATUS. The power-saving control part30receives the notification of the completion of the shutdown, and shifts to S9. In S9, the power-saving control part30outputs the second switching signal POWERSAVE-N “L,” and returns to S4. By outputting the second switching signal POWERSAVE-N “L,” the relay circuit13is turned off, and the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40is stopped.

In S10, satisfaction of a reset condition from the deep sleep mode to the OFF mode is judged. The reset condition to the OFF mode includes the depression of a switch of an operation panel (not shown) by the user and receipt of the print job data from the host PC91, for example. The printer control part40returns to S4when the reset condition is not satisfied. The printer control part40shifts to S11when the reset condition is satisfied.

In S11, the power-saving control part30outputs the second switching signal POWERSAVE-N “H,” and shifts to S12. By outputting the second switching signal POWERSAVE-N “H,” the relay circuit13is turned on, and the main voltages 24V, 5V and the main voltage 3.3V are supplied to the printer control part40. In S12, the power-saving control part30resets the deep sleep mode timer, and returns to S4.

In S13, the power-saving control part30judges whether or not the printer1is in the ON mode. The power-saving control part30shifts to S14in the case when the printer1is in the ON mode. The power-saving control part30shifts to S15in the case when the printer1is not in the ON mode. In S14, the power-saving control part30instructs the printer control part40to perform a shutdown process with an instruction signal DRCT. The printer control part40performs the shutdown process to shunt control parameters and the like to the HDD41that is a nonvolatile memory, and notifies the power-saving control part30of the completion of the shutdown with the state notification signal STATUS. The power-saving control part30inputs the state notification signal STATUS of the completion of the shutdown, and shifts to S15.

In S15, the power-saving control part30outputs the permission signal AUTOOFF OK-P “H” that permits stoppage of the sub voltage 3.3VS0, and shifts to S16. In S16, the power-saving control part30waits for 100 milliseconds. Then, the power-saving control part30shifts to S17. In S17, the power-saving control part30outputs the second switching signal POWERSAVE-N “L,” and completes the process.

As a result, the relay circuit13is turned off, and the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40is stopped. The power-off control part20detects stoppage of the main voltage 3.3V, and outputs the first switching signal SUBPWRON-N “H.” As a result, the PchFET2is turned off and the supply of the sub voltage 3.3VS to the power-saving control part30is stopped.

FIG. 4is a timing chart of an operation after a power source of the printer1inFIG. 1is turned on.

InFIG. 4, T (T1, T2. . . and the like) represents time.FIG. 5and the time charts described later are similar toFIG. 4.

At the time T1, an AC code of the AC power source90is unplugged and power is not provided to the printer1. At this time, the apparatus state is AC OFF state, and all of the main voltages 24V, 5V, and the main voltage 3.3V, the sub voltage 3.3VS0 and the sub voltage 3.3VS are in the stop state. The request signal OFFMODE-P, the permission signal AUTOOFF_OK-P, the first switching signal SUBPWRON-N, and the second switching signal POWERSAVE-N are the OFF state since power is not supplied to the power-off control part20and the power-saving control part30.

At the time T2, the AC cord is plugged in by user operation, and the AC voltage90ais supplied from the AC power source90. Therefore, the sub voltage 3.3VS0 is supplied to the power-off control part20, and the request signal OFFMODE-P and the first switching signal SUBPWRON-N turns into “H.” Since the first switching signal SUBPWRON-N turns into “H”, the PchFET2is turned off, and the sub voltage 3.3VS is not supplied to the power-saving control part30. At this time, the apparatus state shifts to the OFF mode.

At the time T3, the power source switch3is depressed by user operation. At the time T4, the power-off control part20detects that the power source switch3is depressed for a short time, and outputs the first switching signal SUBPWRON-N “L.” Thereby, the PchFET2is turned on, and the sub voltage 3.3VS is supplied to the power-saving control part30. The power-saving control part30outputs the second switching signal POWERSAVE-N “H.” Thereby, the relay circuit13is turned on and the power supply to the main AC/DC converter circuit12is started. The power-off control part20turns on the power source switch LED4. The apparatus state shifts to the ON mode. At the time T5, the main voltages 24V, 5V and the main voltage 3.3V are supplied to the printer control par't40. Thereby, the apparatus state shifts to the ON mode.

FIG. 5is a timing chart of a power-source-off operation when the printer1inFIG. 1is in the ON mode.

At the time T11, the apparatus state is in the ON mode and all of the power is supplied. At the time T12, the power source switch3is depressed by user operation. At the time T13, the power-off control part20detects that the power source switch3is depressed for a short time, and outputs the request signal OFFMODE-P “H” that requests stoppage of the main voltages 24V, 5V and the main voltage 3.3V. Thereby, the power-saving control part30instructs the printer control part40to perform the shutdown process. The power-off control part20turns on and off the power source switch LED4.

At the time T14, the power-saving control part30receives the notification of the completion of the shutdown from the printer control part40though the signal line20c, and outputs the permission signal AUTOOFF_OK-P “H” that permits stoppage of the sub voltage 3.3VS0. At the time T15, the power-saving control part30outputs the second switching signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At this time, the signal POWERSAVE-N is input to the power-off control part20, and the power-off control part20monitors that the signal POWERSAVE-N is output with the signal line B.

At the time T16, the supply of the main voltages 24V, 5V and the main voltage 3.3V is stopped. At the time T17, the power-off control part20detects stoppage of the main voltage 3.3V in the ADC21with the signal line A, and outputs the first switching signal SUBPWRON-N “H.” Thereby, the supply of the sub voltage 3.3VS to the power-saving control part30is stopped. At this time, the power-off control part20monitors that the sub voltage 3.3VS is turned off with the signal line C. At the time T18, the power-off control part20turns off the power source switch LED4. The apparatus state shifts to in the OFF mode.

FIG. 6is a timing chart of a power-source-off operation during the deep sleep mode of the printer1inFIG. 1.

At the time T21, the apparatus state is in the ON mode and all of the power is supplied. At the time T22, since15minutes of the deep sleep mode shift time has been counted, the power-saving control part30outputs the second switching signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At the time T23, the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40is stopped. At this time, the sub voltage 3.3VS is supplied to the power-saving control part30. The apparatus state shifts to the deep sleep mode.

At the time T24, the power source switch3is depressed by user operation. At the time T25, the power-off control part20detects that the power source switch3is depressed for a short time, and outputs the request signal OFFMODE-P “H” that requests stoppage of the main voltages 24V, 5V and the main voltage 3.3V.

At the time T26, the power-saving control part30outputs the permission signal AUTOOFF_OK-P “H” that permits stoppage of the sub voltage 3.3VS0. At the time T27, the power-off control part20outputs the first switching signal SUBPWRON-N “H.” Thereby, the supply of the sub voltage 3.3VS to the power-saving control part30is stopped. At this time, the sub voltage 3.3VS0 is supplied to the power-off control part20. At the time T28, the power-off control part20turns off the power source switch LED4. The apparatus state shifts to the OFF mode.

FIG. 7is a timing chart of an auto-off operation of the printer1inFIG. 1.

At the time T31, the apparatus state of the printer1is in the ON mode and all of the power is supplied. At the time T32, since15minutes of the deep sleep mode shift time has been counted, the power-saving control part30outputs the second switching signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At the time T33, the supply of the main voltages 24V, 5V and the main voltage 3.3V is stopped. As a result, the apparatus state shifts to the deep sleep mode.

At the time T34, 6 hours of the deep sleep mode shift time has been counted, and an auto-off shift condition is satisfied. Thereby, the power-saving control part30outputs the permission signal AUTOOFF_OK-P “H” that permits stoppage of the sub voltage 3.3VS0. At the time T35, the power-off control part20detects the permission signal AUTOOFF_OK-P “H,” and turns on and off the power source switch LED4. At the time T36, the power-off control part20outputs the first switching signal SUBPWRON-N “H.” Thereby, the supply of the sub voltage 3.3VS to the power-saving control part30is stopped. At the time T37, the power-off control part20turns off the power source switch LED4and causes the apparatus state to transit to the OFF mode.

(Effects of the first embodiment)

According to the first embodiment, the power-saving control part30stops the supply the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40, and outputs the permission signal AUTOOFF_OK-P that permits stoppage of the sub voltage 3.3VS0 to the power-off control part20. The power-off control part20is configured to input the permission signal AUTOOFF_OK-P, to stop the supply of the sub voltage 3.3VS to the power-saving control part30after confirming stoppage of the main voltage 3.3V, and to shift to the OFF mode. Therefore, there is an effect in which the auto power-off function is realized with a simple configuration.

(Configuration of Second Embodiment)

FIG. 8is a schematic circuit view of a printer1A according to a second embodiment of the present invention. Components that are common withFIG. 1illustrating the first embodiment are indicated with common symbols.

There is a problem in the configuration of the printer1of the first embodiment that a state of the shutdown cannot be displayed to the user since the power-off control part20stops the sub voltage 3.3VS immediately in the case when the power source switch3is depressed, which requests the power-off during the deep sleep mode or in the case when a condition for the auto power-off is ready. The printer1A of the second embodiment to which an operation panel control part50is added is configured to display that the shutdown is being performed.

The configuration of the printer1A in the second embodiment is similar to the configuration of the first embodiment. The second embodiment has differences that the power-saving control part30and the printer control part40of the first embodiment are replaced with a power-saving control part30A and a printer control part40A, and that the signal line20bthat transmits the permission signal AUTOOFF13OK-P from the power-saving control part30to the power-off control part20is removed and a signal line40Aa as a second instruction part that transmits the permission signal AUTOOFF13OK-P from the printer control part40A to the power-off control part20is added.

Moreover, the second embodiment has a difference that the operation panel control part50is newly connected to the printer control part40A. The operation panel control part50includes a liquid crystal display part (hereinafter referred to as “LCD”)51as a display part that displays the state of the printer1A.

(Operation of Second Embodiment)

FIG. 9is a flow diagram of an operation of a power-saving control part30A inFIG. 8. Steps that are common with those ofFIG. 3illustrating the first embodiment are indicated with common symbols.

S1to S13inFIG. 9are steps that perform the same operations as the power-saving control part30of the first embodiment illustrated inFIGS. 3. S21to S27are steps that perform different operations from those of the first embodiment.

In S13, same as the first embodiment, the power-saving control part30A judges whether or not an apparatus state is in the ON mode. The power-saving control part30A shifts to S23in the case when the apparatus state is in the ON mode. The power-saving control part30A shifts to S21in the case when the apparatus state is not in the ON mode.

In S21, the power-saving control part30A outputs the second switching signal POWERSAVE-N, and shifts to S22. As a result, the main voltages 24V, 5V and the main voltage 3.3V are supplied to the printer control part40A. In S22, the printer control part40A performs a recovery process. In S23, the power-saving control part30A outputs a notification signal INF that asks the printer control part40A to output the permission signal AUTOOFF_OK-P “H” that permits stoppage of the sub voltage 3.3VS0 through the signal line20cas a second notification part, and shifts to S24.

In S24, the power-saving control part30A waits for 100 milliseconds. Then, the power-saving control part30A shifts to S25. In S25, the power-saving control part30A instructs to the printer control part40A to display that the shutdown process is being performed on the LCD51, and shifts to S26. In S26, the printer control part40A performs the shunt process of the control parameters to the memory, the shutdown process for a completion process of HDD41and the like. Then, the power-saving control part30A shifts to S27. In S27, power-saving control part30A outputs the second switching signal POWERSAVE-N “L,” and completes the process.

FIG. 10is a timing chart of an operation after a power source of the printer1A inFIG. 8is turned on.

The operation illustrated inFIG. 10after the power source of the printer1A of the second embodiment is turned on is the same as the operation illustrated inFIG. 4after the power source of the printer1of the first embodiment is turned on.

FIG. 11is a timing chart of a power-source-off operation when the printer1A inFIG. 8is in the ON mode.

The power-source-off operation illustrated inFIG. 11during the operation of the printer1A of the second embodiment is almost the same as the operation illustrated inFIG. 5of the printer1of the first embodiment. The operation at the time T54is different from that of the first embodiment. That is, the operation at the time T51inFIG. 11is the same as the operation at the time T11inFIG. 5. Hereinafter, in the same as described above, the operation at the time T52inFIG. 11is the same as the operation at the time T12inFIG. 5. The operation at the time T53inFIG. 11is the same as the operation at the time T13inFIG. 5. The operation at the time T55inFIG. 11is the same as the operation at the time T15inFIG. 5. The operation at the time T56inFIG. 11is the same as the operation at the time T16inFIG. 5. The operation at the time T57inFIG. 11is the same as the operation at the time T17inFIG. 5. The operation at the time T58inFIG. 11is the same as the operation at the time T18inFIG. 5.

Hereinafter, the operation at the time T54, including the operation at the time before and after the time T54, different from the first embodiment are explained.

At the time T53, the power-off control part20detects that the power source switch3is depressed for a short time, and outputs the request signal OFFMODE-P “H.” At the time T54, the power-saving control part30A notifies the printer control part40A to output the permission signal AUTOOFF13OK-P “H” that permits stoppage of the sub voltage 3.3VS0 though the signal line20cwith the notification signal INF, and the printer control part40A outputs the permission signal AUTOOFF13OK-P through the signal line40Aa.

Moreover, the power-saving control part30A notifies the printer control part40A to display that the shutdown process is being performed on the LCD51with the notification signal INF, and the printer control part40A displays that the shutdown process is being performed on the LCD51. At the time T55, the power-saving control part30A outputs the second switch signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At this time, the power-off control part20monitors that the POWERSAVE-N is output with the signal line B. Hereinafter, the operation is the same as that of the first embodiment illustrated inFIG. 5.

FIG. 12is a timing chart of a power-source-off operation during the deep sleep mode of the printer1A inFIG. 8.

At the time T61, the apparatus state of the printer1A is in the ON mode, and all of the power is supplied. At the time T62, since15minutes of the deep sleep mode shift time has been counted, the power-saving control part30A outputs the second switching signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started.

At the time T63, the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40A is stopped. The apparatus state of the printer1A shifts to the deep sleep mode. At the time T64, the power source switch3is depressed by user operation. At the time T65, the power-off control part20detects that the power source switch3is depressed for a short time, and outputs the request signal OFFMODE-P “H” that requests stoppage of the main voltages 24V, 5V and the main voltage 3.3V.

At the time T66, the power-saving control part30A outputs the second switching signal POWERSAVE-N “H.” Thereby, the supply of the main voltages 24V, 5V and the main voltage 3.3VS0 is started. At the time T67, the power-saving control part30A instructs the printer control part40A to perform the shutdown, and notifies the printer control part40A to output the permission signal AUTOOFF13OK-P “H” that permits stoppage of the sub voltage 3.3VS0 with the notification signal INF, and the printer control part40A outputs the permission signal AUTOOFF_OK-P “H” to the power-off control part20. Moreover, the power-saving control part30A instructs the printer control part40A to display that the shutdown process is being performed on the LCD51, and the printer control part40A displays that the shutdown process is being performed on the LCD51.

At the time T68, the power-saving control part30A receives the notification of the completion of the shutdown from the printer control part40A, and outputs the second switch signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At the time T69, the main voltage 3.3V is stopped. At the time T70, the power-off control part20detects stoppage of the main voltage 3.3V, and outputs the first switching signal SUBPWRON-N “H.” Thereby, the supply of the sub voltage 3.3VS to the power-saving control part30A is stopped. At the time T71, the power-off control part20turns the power source off switch LED4. The apparatus state shifts to the OFF mode.

FIG. 13is a timing chart of an auto-off operation of the printer1A inFIG. 8.

At the time T81, the apparatus state of the printer1A is in the ON mode, and all of the power is supplied. At the time T82, since15minutes of the deep sleep mode shift time has been counted, the power-saving control part30A outputs the second switching signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At the time T83, the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40A is stopped. The apparatus state shifts to the deep sleep mode. At the time T84, the deep sleep mode continues for six hours, and the auto-off shift condition is satisfied. Thereby, the power-saving control part30A outputs the second switching signal POWERSAVE-N “H.” Thereby, the supply of the main voltages 24V, 5V and the main voltage 3.3V to the printer control part40A is started.

At the time T85, the power-saving control part30A notifies the printer control part40A of the shutdown with the notification signal INF, and instructs the printer control part40A to output the permission signal AUTOOFF_OK-P “H” that permits stoppage of the sub voltage 3.3VS0. The printer control part40A outputs the permission signal AUTOOFF_OK-P “H” to the power-off control part20. Moreover, the power-saving control part30A instructs to the printer control part40A to display that the shutdown process is being performed on the LCD51, and the printer control part40A displays that the shutdown process is being performed on the LCD51.

At the time T86, the power-off control part20outputs the request signal OFFMODE-P “H” that requests stoppage of the main voltages 24V, 5V and the main voltage 3.3V.

At the time T87, the power-saving control part30A outputs the second switch signal POWERSAVE-N “L.” Thereby, the decrease of the output of the main voltages 24V and 5V is started. At the time T88, the supply of the main voltages 24V, 5V and the main voltage 3.3V is stopped. At the time T89, the power-off control part20detects stoppage of the main voltage 3.3V in the ADC21, and outputs the first switching signal SUBPWRON-N “H.” Thereby, the supply of the sub voltage 3.3VS to the power-saving control part30A is stopped. At the time T90, the power-off control part20turns off the power source switch LED4. The apparatus state shifts to the OFF mode.

(Effects of the Second Embodiment)

According to the printer1A of the second embodiment, in addition to the effects of the first embodiment, the power-saving control part30A causes the printer control part40A that moves with the main voltages 24V, 5V and 3.3V to display that the printer control part40A is shutting down, and outputs the permission signal AUTOOFF_OK-P that permits stoppage of the sub voltage 3.3VS0 to the power-off control part20after the shutdown is completed. The power-off control part20is configured to input the permission signal AUTOOFF_OK-P, to confirm stoppage of the main voltage 3.3V, to stop the supply of the sub voltage 3.3VS0 to the power-saving control part30A, and to shift to the OFF mode. Therefore, the convenience for a user is improved since the user finds that the printer1A is shutting down.

The present invention is not limited to the above-described embodiments, and other various forms and modifications are possible. For example, the first and second embodiments are explained with the printers1and1A as electronic devices, as examples. However, the embodiments may be widely used in electronic devices such as personal computers, facsimile machines, photocopy machines and the like with a sub power source type power source.

The frequencies of On/Off of the power source switch LED varies according to embodiments. At 1 Hz, 3 Hz and in a preferred range, the frequency may be determined.