JP2011201315A - Portable printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely save data necessary when restarting, before cutting off the power supplied from a battery when remaining capacity of the battery has reduced.SOLUTION: A remaining capacity measuring part 27 measures the remaining capacity of the battery 25. A CPU 10 compares the measured result with a first reference value equivalent to the voltage that enables continuous printing. When the remaining capacity of the battery has reduced to less than the first reference value, the CPU executes an error processing for informing of the shortage of the battery remaining capacity. The CPU 10 compares the measured result by the remaining capacity measuring part 27 with a second reference value lower than the first reference value. When the remaining capacity of the battery 25 has reduced to less than the reference value, the CPU, after saving the data necessary when restarting into a nonvolatile memory 38, allows a power supply control section 24 to forcibly cutoff the power being supplied from the battery 25 to various parts in a portable printer.

Description

  The present invention relates to a portable printer that prints on a printing medium such as paper using a battery as a driving source.

In general, in a portable printer using a battery as a main power source, in order to reduce power consumption during non-operation as much as possible, as shown in the flowchart of FIG. When a certain time has elapsed since the printing operation is not performed or communication is not performed, the CPU that constitutes the control of the microcomputer shifts to the sleep mode and stops the power supply to parts other than the minimum necessary part. Some have low power consumption modes.
Further, in such a portable printer, power consumption is saved after a certain period of time has passed since the power is turned on and no operation SW is pressed, no printing operation is performed, or communication is not performed. In order to do this, there are some that automatically shut off the power. Alternatively, as shown in the flowchart of FIG. 6, when there is a print operation instruction, the remaining capacity of the battery is measured, it is determined whether or not the remaining capacity can be printed, and if the remaining capacity of the battery falls below a certain level, printing is not possible. Some of them are determined to be possible and the printing process is stopped and error processing is performed.

However, regardless of the remaining capacity of the battery, the battery that automatically shifts to the low power consumption mode after a lapse of a certain time after printing or communication is stopped will have the remaining capacity of the battery before shifting to the low power consumption mode. In some cases, the power was suddenly shut off.
Also, in the case of a device that automatically shuts off the power after the lapse of a certain time (transition to auto power off mode), the remaining capacity of the battery disappears before the power is automatically shut off after the lapse of a certain time. There was a case of blocking.
Even if the printer has an auto power-off mode, the user may use it after canceling the auto power-off mode because of poor usability.
In that case, when the battery is used for a long time after being left in a state where the remaining capacity of the battery is low, the remaining capacity of the battery disappears and the battery cannot be used. At this time, there also arises a problem that it is not known why the printer does not operate (it does not know whether the battery is dead).

On the other hand, in a portable printer using a line-type thermal head, if the printing rate of all the dots in one line is high and the printing rate approaches 100%, a large current is supplied from the battery to the thermal head. Battery voltage drops rapidly. This tendency becomes stronger as the remaining capacity of the battery decreases, and when the power supply voltage drop due to the battery increases in this way, the circuit operation may be affected. That is, the battery voltage may become equal to or lower than the circuit operating voltage during printing, and the power supply monitoring circuit connected to the CPU may operate to reset the CPU.
In general, when the power is automatically shut off, the power shut-off program is started before the power is shut off, and necessary data is stored and stored in a memory so that the data can be used at the next restart.

However, as described above, if the power is forcibly cut off without being automatic, the necessary data cannot be saved, and the problem that correct data cannot be acquired at the next restart may occur. there were.
In addition, since there is no remaining battery capacity, there is a problem in that even if a printer whose power has been forcibly cut off is pressed again and the power switch is pressed, it does not restart because there is no remaining battery capacity.

On the other hand, when the above-described portable printer using a line-type thermal head performs printing with a high printing rate in a state where the remaining capacity of the battery is small, a large current flows from the battery to the thermal head, so the output voltage of the battery decreases. Even if the voltage drop is at a level that does not hinder circuit operation, printing tends to be light.
As described above, even if the battery capacity remains to some extent, printing may become thin and the required print quality may not be satisfied.
Therefore, even if the circuit operation is not affected, if the print quality cannot be satisfied as described above, it may be determined that printing is impossible and the power supply may be forcibly shut off. However, in this case, the circuit can operate even if printing cannot be performed. Therefore, operations other than printing, such as a communication standby state from the host device or data processing operations (formatting of print data, etc.), take a long time. Even though it is possible to wait and to process data, it is impossible to do so by shutting off the power supply.

Japanese Patent Laid-Open No. 04-205122 Japanese Patent Laid-Open No. 03-226814 Japanese Patent Laid-Open No. 06-274457

  The present invention has been made in order to solve various problems in such a conventional portable printer. When the remaining capacity of the battery is reduced, the power supply from the battery is cut off before restarting. The purpose is to ensure that necessary data can be stored.

  It is another object of the present invention to allow a host device that sends print data to a portable printer to know when the power supply from the battery is automatically cut off in the portable printer.

  In addition, even if the remaining battery capacity is low, if there is no problem in circuit operation and if it is possible to wait for a communication command from the host and process data, it can be used and the battery can be used more effectively. Also aimed.

The present invention relates to a portable printer that operates using a battery as a drive source, receives print data transmitted from a host device, and performs print processing for executing a print operation on a print medium using a thermal head and a motor. A remaining capacity measuring means for measuring the remaining capacity of the battery, and a first comparing means for comparing a measurement result by the remaining capacity measuring means with a first reference value each time a printing process for one page is performed, When the first comparison unit determines that the remaining capacity of the battery is equal to or greater than the first reference value, the printing process is performed, and the remaining capacity of the battery is lower than the first reference value. And the first comparing means stop the printing operation and notify the host device that printing is impossible, and the measurement result by the remaining capacity measuring means And a second comparison means for comparing with a second reference value that is greater than a possible minimum value and lower than the first reference value, and the remaining capacity of the battery is less than the second reference value A power supply cutoff means for forcibly cutting off the power supply from the battery when the second comparison means determines that the power supply has been lowered, and restarting before forcibly cutting off the power supply from the battery Data used for initial setting of printing conditions at the time is stored in a non-volatile memory, before the power supply from the battery is forcibly cut off, the host device is notified that the power supply is cut off, and before the printing process is performed In addition, initial setting of printing conditions is performed using data stored in the nonvolatile memory.
The present invention relates to a portable printer that operates using a battery as a drive source, receives print data transmitted from a host device, and performs print processing for executing a print operation on a print medium using a thermal head and a motor. The remaining capacity of the battery is measured, and the measurement result is compared with the first reference value every time printing processing for one page is performed. If it is determined, the printing operation is stopped and the host device is notified that printing is not possible. During standby, the remaining capacity of the battery is measured, and this measurement result is calculated from the minimum value that allows circuit operation. If it is determined that the operation is impossible as compared with a second reference value that is larger than the first reference value, the power supply from the battery is forcibly cut off. Before the power supply is forcibly cut off, data used for initial setting of the printing conditions at the time of restart is stored in a non-volatile memory, and before the power supply from the battery is forcibly cut off, the host device is turned on. It is characterized in that the printing condition is initialized with the data stored in the non-volatile memory before the cutoff is notified and the printing process is performed.

The second reference value is desirably a value larger than the minimum value at which circuit operation is possible.
The notifying means notifies the host device that sends print data to the portable printer that the power supply is interrupted before the power supply is interrupted by the power supply interrupting means.
The notification means may include at least one of a wired notification means and a wireless notification means.
When the remaining capacity measuring means is built in the battery pack, the measured value of the remaining battery capacity is always correctly measured even if the battery is replaced.
In addition, as an error process, the battery shortage may be notified.
In that case, even after the printing operation is stopped, the circuit operation is possible until the remaining capacity of the battery decreases to the above-described reference value, and it is possible to keep the communication standby or the data processing state for a long time. .
Furthermore, it is possible to connect an AC adapter as a power source. When the AC adapter is connected, the battery may be charged by power supplied from the AC adapter.

In a portable printer that prints on a printing medium such as paper using a battery as a drive source, if the remaining capacity of the battery is measured and the measurement result falls below a preset reference value, the necessary data is stored in a nonvolatile memory. Since the power supply is automatically shut off after being stored in the memory, the power shutoff program can be surely started before the remaining capacity of the battery runs out, and the necessary data can be stored in the nonvolatile memory.
Before the remaining capacity of the battery runs out, the power supply from the battery is automatically cut off, so when the printer is started by turning on the power switch again, the power supply necessary for the circuit to operate is not performed, There is no problem of not restarting, and it can be operated reliably.

  If the host device is notified before the power supply from the battery is automatically cut off, the host device can know that the power supply in the portable printer has been cut off. Even if it does not operate, the cause can be easily known.

  Even after the remaining battery capacity has been reduced and the continuous printing operation has been stopped, the circuit operates in a standby state where it can operate for a long time until it reaches the reference value for forcibly turning off the power. The battery can be used effectively.

  If the means for measuring the remaining capacity of the battery is built in the battery pack, even if the battery is replaced in the middle, the remaining capacity of the battery is not erroneously measured by the replacement.

1 is a block diagram illustrating a configuration of an embodiment of a portable printer according to the present invention. FIG. It is a block diagram which similarly shows the usage example. It is a circuit diagram which shows an example of the means to interrupt | block the power supply provided in the power supply control part 24 of FIG. It is a flowchart of the process which concerns on this invention by CPU10 of FIG. It is a flowchart which shows the example of the power saving process in the conventional portable printer. It is a flowchart of the process at the time of the printing operation instruction | indication in the conventional portable printer.

Hereinafter, preferred embodiments of a portable printer according to the present invention will be described with reference to the drawings.
First, an example of use of the portable printer according to the present invention will be described with reference to FIG.

  In FIG. 2, the portable printer 1 has a built-in battery pack 28, operates while being supplied with power from the battery in the battery pack, and is connected to an external AC adapter 35 so that an alternating current from a commercial power source is supplied with a predetermined voltage. It is also possible to operate by being supplied with electric power converted into direct current. When the AC adapter 35 is connected, the battery in the built-in battery pack 28 can be charged.

  The portable printer 1 is communicably connected to a host device 36 such as a personal computer via an RC232C interface (I / F), or can communicate with another host device 37 via SS (Spectrum Spread) radio. The print data transmitted from the host devices 36 and 37 is received, and the print processing is performed for each page on a print medium such as paper.

FIG. 1 is a block diagram showing a more detailed configuration of the portable printer 1.
In FIG. 1, a CPU 10 is a central processing unit that performs overall control of the portable printer 1, and constitutes a microcomputer together with a ROM 32 that stores the program and an SRAM (static RAM) 31 that is a working memory. Yes.

  A crystal oscillator 11 for oscillating a clock signal is directly connected to the CPU 10, and an NVRAM 38 that is a nonvolatile memory, a power supply monitoring circuit 30, in addition to the ROM 32 and the SRAM 31, via a CPU bus (not shown). The wireless interface 33, the RS232C interface 34, and the display LED 21 provided on the operation panel 20 and the paper feed switch 22 are also connected.

  The CPU 10 also includes a motor driver 13 for driving the line feed motor 12, a thermal head controller 15 for controlling the thermal head 14, and a cover of the housing as loads for performing the printing operation of the portable printer 1. A cover open switch 16 for detecting the opening, a reflection type sensor 17 for detecting the presence or absence of paper and feeding, a sensor control unit 19 for controlling the transmission type sensor 18, and a power supply control unit 24 are respectively provided with an I / O interface (not shown). Connected through.

The power supply control unit 24 is fed with direct current from the battery 25 or the AC adapter 35 of the battery pack 28 described above, converts it into a required direct current voltage by the DC-DC converter 29, and supplies it to the above-described units.
The battery pack 28 incorporates a battery remaining capacity measuring unit 27 which is a remaining capacity measuring means for measuring the remaining capacity together with the battery 25, and outputs the measurement result to the power supply control unit 24 and the battery charge control unit 26. To do. The remaining battery capacity measuring unit 27 is also a current path between the battery 25 and the power supply control unit 24.

In addition, a battery charge control unit 26 is provided between the battery pack 28 and the power supply control unit 24, and a battery remaining capacity measuring unit 27 is connected to the battery charge control unit 26. The measurement result of (charging state) is input.
When the AC adapter 35 is not connected to the power supply control unit 24, power is supplied from the battery 25 to the power supply control unit 24 via the remaining battery capacity measurement unit 27. When the AC adapter 35 is connected and the battery 25 is not fully charged, the battery 25 is charged from the power supply control unit 24 via the battery charge control unit 26 and the remaining battery capacity measurement unit 27, and the remaining battery capacity is When the full charge is measured by the measuring unit 27, the charging to the battery 25 is stopped.

The power supply control unit 24 is also connected to the CPU 10 for controlling the power supply control unit 24 and the power switch 23 of the operation panel 20.
Further, in the power supply control unit 24, as means for interrupting power supply (power supply) to each part in the portable printer 1, as shown in FIG. A circuit comprising a flop circuit (hereinafter abbreviated as “FF circuit”) 41 is provided.

  The ground is connected to the low active reset terminal (/ RESET) of the FF circuit 41 via the power switch 23, and a signal from the CPU 10 is input to the low active set terminal (/ SET). The output terminal Q of the FF circuit 41 is connected to the base of the transistor 40, the emitter of the transistor 40 is connected to the power supply path of the battery 25 and the like, and the collector is connected to the DC-DC converter 29.

  When the ground level “L” signal is input to the reset terminal of the FF circuit 41 via the power switch 23, the FF circuit 41 is reset and its output terminal Q is set to the low level “L”. When the power is turned on, a current flows from the battery 25 (or the AC adapter 35) to the DC-DC converter 29, and power is supplied from the DC-DC converter 29 to each part.

In this state, when a low level “L” signal is input from the CPU 10 to the set terminal of the FF circuit 41, the FF circuit 41 is set and its output terminal Q becomes high level “H”. Since the power supply path to the DC-DC converter 29 is cut off, no current flows through the DC-DC converter 29, and all power supply from the battery 25 to each part in the portable printer 1 is cut off.
The switch element that opens and closes the power supply path to the DC-DC converter 29 is not limited to a bipolar transistor, and a field effect transistor (FET), a relay, or the like may be used.

  Here, the operation processing by the CPU when the host device 36 or 37 shown in FIG. 2 gives a print operation instruction via the RS232CI / F 34 or the wireless I / F 33 shown in FIG. This will be described with reference to a flowchart.

First, in step S1, initial setting of printing conditions is performed. At this time, if there is data stored in the NVRAM 38, it is set.
In step S2, the remaining battery capacity measurement unit 27 in the battery pack 28 is caused to measure the remaining capacity of the battery 25 via the power supply control unit 24, and the measurement result is read.

  In step S3, it is determined whether printing is possible. This compares the measured value (voltage value) of the remaining capacity of the battery 25 with a first reference value which is a print stop reference value corresponding to a voltage somewhat higher than the minimum capable of continuous printing operation, If it is greater than or equal to the first reference value, it is determined that printing is possible, and if it is less than the first reference value, it is determined that printing is not possible.

If printing is possible, the process proceeds to step S4, the printing process for one page is performed, the process returns to step S2, and the processes of steps S2 to S4 are repeated to print one page at a time on a printing medium such as paper. .
If printing becomes impossible, error processing is performed in step S5. For example, the shortage of the remaining battery capacity is displayed by the display LED 21 of the operation panel 20. Further, it notifies the host devices 36 and 37 shown in FIG. 2 that printing is impossible via the notification means by the RS232CI / F34 or the wireless I / F33.

Thereafter, in step S6, the remaining capacity of the battery 25 is measured again by the battery remaining capacity measuring section 27 via the power supply control section 24, and the measurement result is read.
In step S7, it is determined whether or not circuit operation is possible. This is because the measured remaining capacity value (voltage value) of the battery 25 is a second reference value (absolute value is higher than the first reference value) corresponding to a voltage somewhat higher than the minimum voltage at which circuit operation is possible. If it is equal to or greater than the second reference value, it is determined to be operable, and if it is less than the second reference value, it is determined to be inoperable.

  As a result, if the operation is possible, the operation standby state is set in step S8 and the process returns to step S6. If YES in step S9, the flow advances to step S9 to store and save data necessary for restart in the NVRAM 38, and notify the host device that all power is to be shut off.

  Thereafter, the power is turned off at step S10, and the process is terminated. That is, a low level “L” signal is applied from the CPU 10 to the set terminal of the FF circuit 41 shown in FIG. 3 in the power supply control unit 24, the FF circuit 41 is set to the set state, and its output terminal Q is set to the high level “H”. " As a result, the transistor 40 is turned off and the power supply to the DC-DC converter 29 is cut off, so that the power supply to all the circuits in the portable printer 1 is cut off. Therefore, the CPU 10 and the power supply control unit 24 in FIG.

  In the case of simplifying the above-described processing, when it is determined in step S3 in FIG. 4 that printing is not possible, the host device is notified that printing is impossible instead of error processing or after error processing, and is necessary. After the data is stored in the NVRAM 38 and saved, the power may be turned off to end the process.

  Although the present invention is applied to a printer that performs printing by performing data communication with a host device, it is necessary to shut off all the power sources in one device that exchanges data between two systems. It can be applied to other devices.

  10: CPU, 12: line feed motor, 14: thermal head, 20: operation panel, 23: power switch, 24: power supply control unit, 25: battery, 26: battery charge control unit, 27: battery remaining capacity measurement Part: 28: battery pack, 29: DC-DC converter, 31: SRAM, 32: ROM, 33: wireless interface, 34: RS232C interface, 35: AC adapter, 36, 37: host device, 40: transistor (switch element) ), 41: flip-flop circuit (FF circuit)

Claims (2)

In a portable printer that operates using a battery as a drive source, receives print data transmitted from a host device, and performs print processing for executing a print operation on a print medium using a thermal head and a motor.
A remaining capacity measuring means for measuring the remaining capacity of the battery;
A first comparison unit that compares a measurement result of the remaining capacity measurement unit with a first reference value each time a printing process for one page is performed;
When the first comparison unit determines that the remaining capacity of the battery is equal to or greater than the first reference value, the printing process is performed, and the remaining capacity of the battery is lower than the first reference value. And means for notifying the host device that printing is impossible, by stopping the printing operation when the first comparing means determines,
Second comparison means for comparing a measurement result by the remaining capacity measurement means with a second reference value that is larger than a minimum value capable of circuit operation and lower than the first reference value;
When the second comparison means determines that the remaining capacity of the battery is lower than the second reference value, power supply cutoff means for forcibly cutting off the power supply from the battery;
Provided,
Before forcibly cutting off the power supply from the battery, the data used for initial setting of the printing conditions at the time of restart is stored in a nonvolatile memory,
Before forcibly shutting off the power supply from the battery, notify the host device to shut off the power,
A portable printer characterized by performing initial setting of printing conditions with data stored in the non-volatile memory before performing a printing process. In a portable printer that operates using a battery as a drive source, receives print data transmitted from a host device, and performs print processing for executing a print operation on a print medium using a thermal head and a motor.
The remaining capacity of the battery is measured, and the measurement result is compared with the first reference value every time printing processing for one page is performed. If it is determined, the printing operation is stopped and the host device is notified that printing is impossible,
During standby, the remaining capacity of the battery is measured, and the measurement result is compared with a second reference value that is greater than the minimum value at which circuit operation is possible and lower than the first reference value. If it is determined that the operation is impossible, the power supply from the battery is forcibly cut off,
Before forcibly cutting off the power supply from the battery, the data used for initial setting of the printing conditions at the time of restart is stored in a nonvolatile memory,
Before forcibly shutting off the power supply from the battery, notify the host device to shut off the power,
A portable printer characterized by performing initial setting of printing conditions with data stored in the non-volatile memory before performing a printing process.

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