JP2003080800A - Electronic apparatus and power consumption control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus and a power consumption control method by which power consumption is reduced furthermore. SOLUTION: In the electronic apparatus which can operate by both a secondary battery chargeable as a power source for operation and an external power supply unit, it is detected whether or not the external power supply unit is connected to an external power source, and it is detected whether or not a switch for turning on/off the operation of the electronic apparatus is in an off state. An MPU for controlling the apparatus checks a charging state of the secondary battery on the basis of the detected results and controls in accordance with the charging state to turn on/off a semiconductor switch set to an input part for power to be supplied from the external power supply unit so as to charge the secondary battery with the use of a charging control circuit which charges the secondary battery with the use of power supplied from the external power supply unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device and a power consumption control method, and operates both as a power supply for operation, for example, a rechargeable secondary battery and an external power supply unit for converting an AC power supply into a DC power supply. The present invention relates to a possible electronic device and a power consumption control method thereof.

[0002]

2. Description of the Related Art In recent years, many electronic devices such as portable personal computers, mobile phones, video cameras, and portable printers have been put on the market.

In consideration of portability, these electronic devices can be used in a state where they are not connected to a household power source, that is, cordless. Therefore, in these electronic devices, without connecting to a household AC power supply using a power cord, a battery or the like is built into the electronic device, or a unit such as a battery pack containing a battery is externally connected to the electronic device. It is configured to be used.

A rechargeable battery, a so-called secondary battery, is often used as a power source for these electronic devices. Known secondary batteries include, for example, nickel-cadmium batteries, nickel-hydrogen batteries, lithium-ion batteries, and the like.

On the other hand, these electronic devices are connected to the AC power source so that they can be operated with the AC power source at home, office, etc.
An external power supply unit (generally,
A so-called AC adapter is connectable, and the charging current of the battery is also supplied from this external power supply unit. This battery can be charged only when the electronic device is connected to an AC power source and the power is on, and when the device is not driven by a large current such as mechanical operation and there is sufficient power, or when the electronic device is connected to an AC power source. In addition, it is generally performed when the power is off.

Therefore, even when the electronic device is powered off, if the external power supply unit is connected, it is necessary that the electronic device can be automatically charged without the user's operation.

For this reason, the electronic equipment as described above does not employ a structure in which the AC power supplied to the external power supply unit is shut off by a mechanical switch when the equipment is powered off. In general, even when power is off, power is supplied to the electronic device side, the MPU built in the electronic device is operated, and on / off of the power switch on the device is always detected.

In such a configuration, in order to reduce the power consumption of the electronic device when the power is off, the clock frequency of the MPU and the control circuit that controls the device is decreased or stopped compared to when the power is turned on. It is generally done.

[0009]

However, in the above-mentioned conventional example, although the power consumption is reduced as described above, it is still necessary to supply power to the logic circuit including the MPU of the electronic device, and therefore, there is a certain degree. It was unavoidable to consume more power than the value.

In addition, a conventional external power supply unit (AC
The adapter consumes about 0.3 to 0.5 w of electric power even without load, but when it takes a load, that is, when some kind of device operation occurs on the electronic device side, the power consumption increases at an accelerated rate. Tends to. Therefore, in order to reduce the power consumption of the entire system including the external power supply unit and the electronic device to about 0.5 w or less when the power is turned off, the power consumption on the electronic device side when the power is turned off is almost "0". There is a need to.

Further, in view of the current situation that reactive power at the time of power-off of electronic equipment is a problem due to recent interest in energy saving and strengthening of regulations, it is required to further reduce power consumption.

The present invention has been made in view of the above conventional example, and an object thereof is to provide an electronic device and a power consumption control method for further reducing power consumption.

[0013]

In order to achieve the above object, the electronic equipment of the present invention has the following configuration.

That is, the electronic device is capable of operating with both a rechargeable secondary battery as an operating power source and an external power supply unit, wherein the secondary battery is powered by the power supplied from the external power supply unit. A charging control circuit for charging to
The external power supply unit includes a semiconductor switch provided in an input unit for the power supplied from the external power supply unit, a switch for turning on / off the electronic device operation, and an MPU for device control, and the external power supply unit is an external power source. And the switch is in the off state, the MP
U comprises an electronic device characterized by checking the state of charge of the secondary battery and controlling ON / OFF of the semiconductor switch to charge the secondary battery by using the charge control circuit according to the state of charge. .

When the external power supply unit is connected to an external power source, the semiconductor switch is turned on for a certain period of time to supply electric power, and the MPU is turned on during the certain period of time. After fixing the battery to the battery, according to the state of charge of the secondary battery, the semiconductor switch is controlled to turn off when the secondary battery is in a fully charged state, and when the secondary battery is not in a fully charged state, the charge control circuit It is preferable to control so that the charging operation is performed by using and to turn off the semiconductor switch after the charging is completed.

Further, the electronic apparatus of the present invention includes a portable printer, and the printer preferably includes an ink jet recording head for ejecting ink to perform recording,
In particular, it is preferable that the inkjet recording head is provided with an electrothermal converter for generating heat energy applied to the ink in order to eject the ink by using the heat energy.

Furthermore, the external power supply may be an AC power supply, and the external power supply unit may be an AC adapter for converting the AC power supply into a DC power supply. in this case,
Further, it is preferable to have a DC-DC converter which inputs the DC power and converts it into a desired voltage.

Furthermore, as the semiconductor switch, F
ET included.

According to another aspect of the present invention, there is provided a power consumption control method for controlling power consumption of an electronic device which can be operated by both a rechargeable secondary battery as an operating power source and an external power supply unit. A first determining step of determining whether the external power supply unit is connected to an external power source, a second determining step of determining whether a switch for turning on and off the operation of the electronic device is in an off state, and The MPU that performs device control checks the state of charge of the secondary battery according to the determination results in the first and second determination steps, and uses the power supplied from the external power supply unit to supply the secondary battery to the secondary battery according to the state of charge. ON / OFF of a semiconductor switch provided at an input portion of electric power supplied from the external power supply unit so as to charge the secondary battery using a charging control circuit for charging Comprising a power control method characterized by a control step of controlling.

With the above-described structure, the present invention is an electronic device that can operate with both a rechargeable secondary battery as an operating power supply and an external power supply unit, and whether the external power supply unit is connected to the external power supply. Determine if
It is determined whether or not the switch for turning the electronic device operation on and off is in the off state, and according to these determination results,
The MPU that controls the equipment checks the state of charge of the secondary battery, and charges the secondary battery using the charge control circuit that charges the secondary battery using the power supplied from the external power supply unit according to the state of charge. The on / off of the semiconductor switch provided in the input portion of the power supplied from the external power supply unit is controlled.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an external perspective view of a portable ink jet printer 1 which is a typical embodiment of the present invention. Because of its portability, this inkjet printer is not only a household AC power supply (AC) but also a rechargeable battery such as nickel-cadmium battery, nickel-hydrogen battery, lithium-ion battery, Ni-Cd, lithium-hydrogen, etc. The secondary battery can be used as a power source.

This ink jet printer has a structure capable of both color printing and black-and-white mono-color printing. However, when it is considered as a device dedicated to black-and-white mono-color printing, it contains black ink described below. Only the ink cartridge that has been used is attached to the recording head.

As shown in FIG. 1, a multi-nozzle recording head 102 having 128 nozzles and a cartridge guide 103 are mounted on a carriage 101. The recording head 102 uses black (K) ink, Alternatively, cyan (C), magenta (M), yellow (Y), and black (K) inks are ejected, respectively. During the printer recording operation, the recording head 102 is equipped with the ink cartridge 110 containing the black ink and the ink cartridge 111 containing the other three color inks. Then, magenta (M), yellow (Y), and black (K) inks are supplied from the respective ink cartridges, and each nozzle of the recording head is driven via a flexible cable (not shown) in which a large number of conductors are arranged. Signal is supplied.

On the other hand, the carriage 101 is mounted on the two guide rails 104 to 105, and the carriage 1
The endless belt 109 connected to 01 is driven by a carrier motor (described later) to cause the carriage 101 to reciprocate in the X direction (hereinafter, this X direction is referred to as the main scanning direction). Further, the recording paper 106 is stretched by the auxiliary roller 107 to help the recording paper to be conveyed smoothly. The transport roller 108 is driven by a transport motor (described later) to feed the recording paper 106 in the Y direction (hereinafter, this Y direction is referred to as the sub-scanning direction).

FIG. 2 is a block diagram showing the configuration of the control circuit of the ink jet printer. In FIG. 2, 170
Is an interface for inputting a recording signal from an external device such as a host computer, 171 is an MPU, 17
A ROM 173 stores a control program (including a character font if necessary) executed by the MPU 171.
Is a DRAM for temporarily storing various data (recording data, recording data supplied to the recording head, etc.). A gate array 174 controls the supply of print data to the print head 102.
0, MPU 171, and RAM 173 are also controlled for data transfer. Reference numeral 179 is a carrier motor for moving the recording head 102 in the main scanning direction, and 178 is a conveyance motor for conveying recording paper. Reference numeral 175 is a head driver for driving the recording head, and 176 to 177 are motor drivers for driving the carry motor 178 and the carrier motor 179, respectively.

The operation of the control circuit will be briefly described. When a recording signal is input to the interface 170, the gate array 1
The recording signal is converted between the 74 and the MPU 171 into recording data for printing. Then, the motor driver 17
6 and 177 are driven, and the head driver 175
The recording head is driven according to the recording data sent to
The recording operation is performed.

Although an ink jet printer is explained here as a typical example of portable electronic equipment,
In addition to the above, the present invention is applicable to various types of devices such as a laptop personal computer, a palmtop personal computer, a digital video camera, and a mobile terminal that can access the Internet, which can operate with a secondary battery and an AC power supply. Applicable to electronic devices.

FIG. 3 is a block diagram showing a detailed configuration of a power supply unit of an electronic device such as the portable ink jet printer 1.

In FIG. 3, reference numeral 1 is a portable ink jet printer (hereinafter referred to as printer) shown in FIG.
Is a power supply unit (hereinafter referred to as an AC adapter) for converting alternating current (AC) power supplied from a household outlet or the like into DC power to supply power to the printer 1; and 3 is a secondary battery for supplying power to the printer 1. Is.

When only the secondary battery 3 is connected to the printer 1, electric power is supplied to the printer 1 via the path 1a → the charge control circuit 10 → the path 1b. Further, when the AC adapter 2 is connected to the printer 1, power is supplied from the AC adapter 2 regardless of the connection of the secondary battery 3. That is, the AC power supplied via the path 1c is converted into the DC power by the AC adapter 2 and the path 1d is supplied.
Is input to the printer 1 via the path 1d → the FET (field effect transistor) 11 which is a semiconductor switch → the path 1
Electric power is supplied via e.

Through the above route, the secondary battery 3 or AC
The power supplied from the adapter 2 is stepped down or stepped up to a specified voltage by the DC-DC converters 12 and 13, and is supplied as a logic operation voltage Vcc of the printer 1 and a driving voltage V _H of the mechanical portion of the printer 1 respectively. To be done. Further, when the secondary battery 3 is connected, the secondary battery 3 is not in the fully charged state, and the printer 1 has a sufficient power consumption, the AC adapter 2 → the charge control circuit 10
Charging is done via the.

Next, the configuration and power on / off sequence of the printer 1 will be described in detail with reference to FIGS. 4 to 5 which are timing charts showing transitions of main signals shown in FIG.

As shown in FIG. 3, the printer 1 is provided with a power switch 17 for instructing ON / OFF of the operation of the printer apparatus.
Is provided, the output signal 1f output from the power switch 17 is read into the MPU 171 via the input port 18, and the output signal 1g of the output port 19 controls ON / OFF of the transistor 20.

First, when the AC adapter 2 is connected to the printer 1 in a state where it is connected to an AC power outlet, or when it is connected to the AC power outlet while being connected to the printer 1, the input voltage rises in the path 1d. . In addition,
Here, the power switch 17 is pushed down and the power is not turned on. The path 1d is F which is a switch element.
It is connected to the source of ET11 and is biased by resistors R1 and R2, but since the capacitor C1 is inserted between the resistor R2 and the ground, the resistor R1
1, R2 and the capacitor C1 form an integrator circuit, and F
The gate potential 1i of ET gradually rises from "0" V with a time constant determined by R1, R2, and C1 as shown in FIG.

On the other hand, since the FET 11 is a P channel, the FET 11 is turned on until the source potential minus several V. Therefore, the drain potential 1e of the FET 11 rises at almost the same timing as the source potential 1d, and supplies power to the printer 1.

If the control is left uncontrolled, the FET 11 turns off and the drain voltage 1e drops to "0" at the time when the gate potential 1i becomes equal to or higher than the specified voltage, as shown by the dotted line in FIG. It becomes V. Therefore, before the FET 11 is turned off, the reset released MPU 171 sets the output signal 1g of the output port 19 to the “H” level and turns on the transistor 20 to fix the gate potential 1i to the on potential.

After that, the MPU 171 detects the charging control circuit 1
If the secondary battery 3 is required to be charged via 0, and the charging is not required in the fully charged state, the output signal 1g of the output port 19 is set to "L" level to turn off the transistor 20. When the transistor 20 turns off, the gate potential 1i rises according to the time constant of the integrating circuit composed of the resistors R1, R2, and the capacitor C1, and when the gate potential reaches or exceeds the specified voltage, the FET 11 turns off. The drain voltage 1e becomes "0" V, the logic circuit does not operate, and the power consumption on the printer side becomes almost zero.

In FIG. 3, when the output connector of the AC adapter 2 is removed, the diode D2 and the resistor R3 transfer the electric charge charged in the capacitor C1 to the positive terminal of the capacitor C1 → the diode D2 → the resistor R3 → the capacitor It plays the role of discharging in the path of the negative terminal of C1, and it is inserted if necessary.

In this discharge circuit, it is also possible to connect the cathode of the diode D2 to the drain voltage 1e, which is the output line of the FET 11, without using the resistor R3, and discharge using the impedance of the printer 1. .

Next, FIG. 5 shows a circuit operation from the state in which the AC adapter 2 is connected to the AC power source until the user presses the power switch 17 to re-supply electric power to the printer 1 to operate it. This will be described with reference to the timing chart.

Before the start of the timing chart shown in FIG. 5 (depression of the power switch 17), electric power is supplied from the AC adapter 2 to the path 1d, but the FET is used.
Since 11 is turned off, the power supply to the circuit inside the printer is cut off.

In this state, when the user presses the power switch 17 to operate the printer 1, one terminal of the power switch 17 is connected to the ground, so that the potential of the signal line 1h is grounded via the diode D1. The gate potential 1i becomes close to the level, the gate potential 1i divided by the resistors R1 and R2 is biased, and the FET 11 is turned on. As a result, the drain voltage 1e of the FET 11 rises,
Via the DC-DC converter 12, logic voltage Vcc
Are supplied to the logic circuit including the MPU 171 inside the printer.

When the logic voltage Vcc exceeds a certain level, the reset circuit 21 sets the reset signal 1j to "L" level for a prescribed time (T) to reset the MPU 171. After the reset operation is completed and the reset of the MPU 171 is released, the MPU 171 executes the control program stored in the ROM 172 to control the printer 1. In the initial control according to the control program stored in the ROM 172, the output signal 1g of the output port 19 is controlled to the “H” level, and the transistor 20 is turned on. By this operation, the potential of the signal line 1h is fixed to the “L” level even after the power switch 17 has been pressed down, the FET 11 continues to be turned on, and the state where the power is supplied from the AC adapter 2 is maintained. And printer 1
Is in operation.

Next, the printer 1 is in an operating state, that is, AC.
From the state where power is being supplied from the adapter 2 to the internal circuit of the printer 1 via the FET 11, the power switch 17
By pressing, the power supply to the printer 1 side is cut off,
The operation of the circuit until the printer 1 is turned off will be described with reference to FIG.

First, when the AC adapter 2 is supplying power to the printer 1, the potential of the signal line 1h is close to the ground level because the transistor 20 is turned on via the output port 19 as described above. It is fixed to.

In this state, press the power switch 17,
Then, when released, a pulse as shown in FIG. 5 is output to the power switch output signal 1 f, and this is input to the input port 18.

On the other hand, the MPU 171 has the power switch 17
When it is detected via the input port 18 that the button has been pressed, the power off sequence is started. In this sequence, the MPU 171 first outputs the output signal 1 of the output port 19.
Change g to "L" level. When the output signal 1g becomes "L" level, the transistor 20 is turned off, the potential of the signal line 1h and the gate voltage 1i of the FET 11 become the same as the source potential 1d, and as a result, F
The ET 11 is turned off, the power supply from the AC adapter 2 is cut off, and the logic power supply Vcc of the printer 1, which is the output of the DC-DC converter 12, also drops. Then, when the logic power supply Vcc falls below a certain level, the output of the reset circuit 21, that is, the signal 1j becomes "L" level.

As a result, it is possible to prevent the transistor 20 caused by the output signal of the output port 19 becoming indefinite by mistake from being turned on.

Finally, the control procedure executed by the MPU 171 when the printer 1 is powered on / off will be described with reference to the flowchart shown in FIG.

Here, as described above, the user pushes the power switch 17 to operate the printer 1, and as a result, the logic voltage Vcc is changed to the MPU 1 inside the printer.
It is assumed that the reset is released after a specified time (T) after the power is supplied to the logic circuit including 71, the power is supplied to the printer 1, and the voltage is applied to the logic circuit including the MPU 171. As a result, the MPU 171 becomes R
The program stored in the OM 15 is executed and control is started.

After the reset is released, first, step S1
In 01, by outputting a signal of "H" level to the output port 19 and turning on the transistor 20, the FET
11 is fixed in the ON state so that power is continuously supplied from the AC adapter 2.

Next, in step S102, the input port 1
The output signal 1f to 8 is read, and it is checked whether the power switch 17 of the printer 1 is pressed.
Here, when it is determined that the power switch 17 is not pressed, it is determined that the AC adapter 2 is only connected to the printer 1 and the user does not want to activate the printer 1, and the process proceeds to step S103. .

In step S103, it is checked whether or not a secondary battery is attached, and further, in step S104, which follows.
Then, check whether the secondary battery needs to be charged. In these steps, the secondary battery is not installed,
Alternatively, if it is determined that charging is not required even if the device is attached, the process proceeds to step S107. On the other hand, if it is determined that the secondary battery is installed and charging is required, the process proceeds to step S105,
In step S106, the charging operation is performed until the fully charged state is reached while determining whether or not the fully charged state is reached. Then, if it is determined in step S106 that the secondary battery is in a fully charged state, the process proceeds to step S107.
Proceed to.

In step S107, an "L" level signal is output to the output port 19 to turn off the transistor 20 to turn off the FET 11 and cut off the power supply from the AC adapter 2.

When it is determined in step S102 that the power switch 17 is pressed, the process proceeds to step S103 to operate the printer 1. During the operation of the printer 1, the state of the power switch 17 is always checked by polling or interruption in step S104. When it is determined in step S104 that the power switch 17 is pressed during the operation of the printer 1, the process proceeds to step S105 to end the operation currently being executed,
After that, the process proceeds to step S107 to execute the above-described process to cut off the power supply from the AC adapter 2.

Therefore, according to the above-described embodiment, it is possible to operate with both a rechargeable secondary battery as an operating power source and an AC adapter for converting an alternating current (AC) power source into a DC power source, such as a printer. In an electronic device, a semiconductor switch is provided at an input part of an external power supply, and when the power is turned off, the semiconductor switch is turned off to cut off the power supply. Therefore, the power supply from the DC-DC converter to each part of the device is also stopped, and the AC The power consumption of the entire system including the adapter can be reduced.

Further, when the AC adapter is connected to an alternating current (AC) outlet, the MPU 171 starts operating while the semiconductor switch is on for a certain period of time to supply power to the apparatus, and the semiconductor switch is turned on. It is possible to continue. As a result, the state of charge of the secondary battery can be checked and charging can be performed if necessary.

In the embodiment described above, when the AC adapter is connected to an alternating current (AC) outlet,
As an example of the method of turning on the semiconductor switch for a certain period of time, the integrator circuit including the resistors R1 and R2 and the capacitor C1 has been described. However, the present invention is not limited to this. You may implement the same function.

Further, as the power switch provided on the printer side for operating the printer, the tact switch which is turned on when the switch is pressed has been described as an example, but the present invention is not limited to this. Absent. For example, other types of switches such as a slide switch can also be applied to the present invention. Further, the FET has been exemplified as the semiconductor switch for cutting off the power from the external power source, but it goes without saying that another type of transistor can be used.

In the above embodiments, the droplets ejected from the recording head have been described as ink, and the liquid contained in the ink tank has been described as ink. It is not limited. For example, an ink tank may contain a treatment liquid such as a treatment liquid ejected onto a recording medium in order to improve the fixability and water resistance of a recorded image or to improve the image quality.

In the above-described embodiment, particularly in the ink jet recording system, a means (for example, an electrothermal converter or a laser beam) for generating heat energy as energy used for ejecting ink is provided. High density and high definition recording can be achieved by using a method of causing a change in ink state by energy.

Regarding its typical structure and principle, see, for example, US Pat. Nos. 4,723,129 and 4,740.
What is done using the basic principles disclosed in 796 is preferred. This method can be applied to both the so-called on-demand type and continuous type, but especially in the case of the on-demand type, liquid (ink)
By applying at least one drive signal to the electrothermal transducer arranged corresponding to the sheet or liquid path in which is stored, which corresponds to the recorded information and gives a rapid temperature rise exceeding nucleate boiling. Since the electrothermal converter is caused to generate heat energy to cause film boiling on the heat-acting surface of the recording head, as a result, bubbles in the liquid (ink) corresponding to the drive signal in a one-to-one relationship can be formed. It is valid. The liquid (ink) is ejected through the ejection openings by the growth and contraction of the bubbles to form at least one droplet. It is more preferable to make this drive signal in a pulse shape, because bubbles can be grown and contracted immediately and appropriately, and thus a liquid (ink) with excellent responsiveness can be achieved.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. If the conditions described in US Pat. No. 4,313,124 of the invention relating to the rate of temperature rise on the heat acting surface are adopted, more excellent recording can be performed.

As the constitution of the recording head, in addition to the combination constitution of the discharge port, the liquid passage, and the electrothermal converter (the linear liquid passage or the right-angled liquid passage) as disclosed in the above-mentioned respective specifications, The present invention also includes configurations using US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose configurations in which the heat-acting surface is arranged in a bending region. In addition, for multiple electrothermal converters,
Japanese Unexamined Patent Publication No. 59-123670, which discloses a configuration in which a common slot is used as a discharge portion of the electrothermal converter, and Japanese Patent Laid-Open No. 59-63, which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy is associated with the discharge portion. A configuration based on Japanese Patent No. 138461 may be used.

Further, as a full line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be increased by combining a plurality of recording heads as disclosed in the above-mentioned specification. Either of the structure satisfying the requirement or the structure as one recording head integrally formed may be used.

In addition to the cartridge type recording head in which the ink tank is integrally provided in the recording head itself described in the above embodiment, the recording head is mounted on the main body of the apparatus, so that the electrical connection with the main body of the apparatus is improved. A replaceable chip-type recording head that enables various connections and supply of ink from the apparatus main body may be used.

Further, it is preferable to add recovery means for the recording head, preliminary means, etc. to the structure of the recording apparatus described above because the recording operation can be made more stable. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or sucking means, electrothermal converters or heating elements other than these, or preheating means by a combination thereof. Further, provision of a preliminary ejection mode for performing ejection different from recording is also effective for stable recording.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, but the recording head may be integrally formed or a plurality of combinations may be used. Alternatively, the device may be provided with at least one of full-color mixed colors.

In the above-described embodiments, the explanation is made on the assumption that the ink is a liquid, but even if the ink is solidified at room temperature or lower, it should be softened or liquefied at room temperature. Or, in the inkjet method, it is general that the temperature of the ink itself is adjusted within a range of 30 ° C. or higher and 70 ° C. or lower to control the temperature of the ink so that the viscosity of the ink is in a stable ejection range.
It suffices that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy from being used as energy for changing the state of the ink from the solid state to the liquid state,
Alternatively, in order to prevent the ink from evaporating, an ink that solidifies in a standing state and liquefies by heating may be used. In any case, by applying heat energy, such as ink that is liquefied by applying heat energy according to the recording signal and liquid ink is ejected, or that begins to solidify when it reaches the recording medium. The present invention can be applied to the case where an ink having a property of being liquefied for the first time is used. In such a case, the ink is retained as a liquid or solid in the recesses or through holes of the porous sheet as described in JP-A-54-56847 or JP-A-60-71260. It may be configured to face the electrothermal converter. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition, as a form of the recording apparatus according to the present invention, in addition to one provided integrally or separately as an image output terminal of information processing equipment such as a computer, a copying apparatus combined with a reader or the like, and further transmission / reception It may take the form of a facsimile machine having a function.

Even when the present invention is applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), a device including one device (for example, a copying machine or a facsimile device). Etc.)

Further, an object of the present invention is to supply a storage medium (or recording medium) recording a program code of software for realizing the functions of the above-described embodiments to a system or apparatus, and to supply a computer of the system or apparatus ( Alternatively, by the CPU or MPU) reading and executing the program code stored in the storage medium,
It goes without saying that it will be achieved. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also based on the instruction of the program code,
An operating system (OS) running on the computer does some or all of the actual processing,
It goes without saying that the processing includes the case where the functions of the above-described embodiments are realized.

Further, after the program code read from the storage medium is written in the memory provided in the function expansion card inserted in the computer or the function expansion unit connected to the computer, based on the instruction of the program code. , The CPU provided in the function expansion card or the function expansion unit performs some or all of the actual processing,
It goes without saying that the processing includes the case where the functions of the above-described embodiments are realized.

[0076]

As described above, according to the present invention, in an electronic device capable of operating with both a rechargeable secondary battery as an operating power supply and an external power supply unit, the external power supply unit is an external power supply. To determine whether or not the switch that turns on and off the operation of the electronic device is in the off state, and according to these determination results, the MPU that controls the device checks the charging state of the secondary battery. , According to the state of charge, to charge the secondary battery using the power supplied from the external power supply unit to charge the secondary battery using the charging control circuit to the input unit of the power supplied from the external power supply unit. Since the on / off of the provided semiconductor switch is controlled, for example, if the rechargeable battery is fully charged and the switch is off, the power consumption of the electronic device is reduced. Pot there is an effect that can be made zero.

Further, for example, when the secondary battery is not in the fully charged state, the secondary battery is charged according to the charged state even if the switch is off, and automatically when the charging is completed. Since it is also possible to cut off the power supply, there is also an advantage that both power consumption reduction when the electronic device is switched off and ease of use can be achieved.

[Brief description of drawings]

FIG. 1 is an external perspective view of a portable inkjet printer that is a typical embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a control circuit of the portable inkjet printer shown in FIG.

FIG. 3 is a block diagram illustrating a detailed configuration of a power supply unit of an electronic device such as the portable inkjet printer 1.

FIG. 4 is a timing chart showing transitions of main signals of the control circuit when the AC adapter is connected.

FIG. 5 is a timing chart showing transitions of main signals of the control circuit when the power switch is turned on / off.

FIG. 6 is a flowchart showing a control procedure of the MPU.

[Explanation of symbols]

1 printer 2 External power supply device (AC adapter) 3 secondary battery 10 Charge control circuit 11 FET 12, 13 DC-DC converter 17 power switch 18 input ports 19 output ports 21 Reset circuit 171 MPU 172 ROM 173 DRAM

Claims (10)

[Claims] 1. An electronic device capable of operating with both a rechargeable secondary battery as an operating power source and an external power supply unit, wherein the secondary battery is powered by using the power supplied from the external power supply unit. A charge control circuit that charges the battery, a semiconductor switch that is provided in an input section of the power supplied from the external power supply unit, a switch that turns on and off the electronic device operation, and an MPU that controls the device, When the external power supply unit is connected to an external power source and the switch is in an off state, the MPU
An electronic device that checks the state of charge of the secondary battery and controls ON / OFF of the semiconductor switch to charge the secondary battery using the charge control circuit according to the state of charge. 2. The electronic device according to claim 1, wherein the semiconductor switch supplies power by turning on the external power supply unit for a certain period of time when the external power supply unit is connected to an external power supply. 3. The MPU controls the semiconductor switch to be turned off when the secondary battery is in a fully charged state according to the charging state after fixing the semiconductor switch to an on state during the certain time. When the secondary battery is not in a fully charged state, the charging control circuit is used to control the charging operation, and after the charging is completed, the semiconductor switch is controlled to be turned off. The electronic device according to claim 2. 4. The electronic device according to claim 1, wherein the electronic device includes a portable printer. 5. The electronic device according to claim 4, wherein the portable printer includes an inkjet recording head that ejects ink to perform recording. 6. The ink jet recording head comprises an electrothermal converter for generating heat energy applied to the ink in order to eject the ink by using the heat energy. Electronic device described in. 7. The external power supply is an AC power supply, and the external power supply unit is an AC adapter that converts the AC power supply into a DC power supply.
Electronic device described in. 8. The electronic device according to claim 7, further comprising a DC-DC converter which receives the DC power and converts the DC power into a desired voltage. 9. The electronic device according to claim 1, wherein the semiconductor switch is a FET. 10. A power consumption control method for controlling power consumption of an electronic device capable of operating with both a rechargeable secondary battery as an operating power source and an external power supply unit, wherein the external power supply unit is external. A first determining step of determining whether or not it is connected to a power source, a second determining step of determining whether or not a switch for turning on and off the electronic device operation is in an off state, and the first and second determining steps According to the discrimination result in
The MPU that controls the device checks the state of charge of the secondary battery, and according to the state of charge, the secondary battery is charged using a charge control circuit that charges the secondary battery with the electric power supplied from the external power supply unit. And a control step of controlling on / off of a semiconductor switch provided at an input portion of electric power supplied from the external power supply unit so as to charge a battery.