JP2005331462A - Method and detector for detecting voltage reduction in line printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a detector for detecting a voltage reduction in a line printer capable of using any of a primary battery and a secondary battery as a driving source, and capable of consuming efficiently a battery capacity in response to a change of an ambient temperature to use a residual capacity of the battery to the maximum. <P>SOLUTION: A terminal voltage in a nonoperation of the battery 4 and a terminal voltage in an operation thereof are detected to calculate a discharge characteristic of the battery 4 from a difference between the terminal voltage in the nonoperation and the terminal voltage in the operation, the battery 4 is determined referring to the discharge characteristics of the primary battery and the secondary battery, and a detection value of an end voltage is changed selectively in response to a kind of the battery 4. The ambient temperature is detected further to calculate a temperature of the battery 4 based on the ambient temperature, and the detection value of the end voltage is set selectively from the stored detection value of the end voltage in response to the temperature of the battery 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a line printer using a battery as a drive source, and in particular, either a primary battery or a secondary battery can be used as a drive source, and the battery capacity is maximized according to the environmental temperature. The present invention relates to a method and an apparatus for detecting a reduced voltage in a line printer.

  In general, a battery is connected to an electric device that uses the battery as a drive source, and when the electric device is operated, the electric power is discharged, and the output voltage is gradually decreased to stably supply the electric power. When the voltage reaches a voltage (end voltage) that cannot be generated, the output voltage rapidly decreases.

  In addition, since the battery is discharged using a chemical reaction, and the output voltage has temperature-dependent characteristics, the output voltage changes depending on the environmental temperature in which the battery is used. The lower the environmental temperature, the lower the output voltage. It has the characteristic of end up.

  For this reason, in conventional electric devices that use batteries as a drive source, especially electric devices with large output power, the circuit output of the electric devices is unstable due to the sudden drop in the output voltage when the output voltage of the battery reaches the end voltage. In order to avoid this, there is one that detects an output voltage corresponding to the environmental temperature and corrects the usable battery capacity at this output voltage, that is, the remaining battery capacity.

  As an example of such an electric device using a conventional battery as a drive source, a printer engine unit that performs printing based on print data transmitted from a personal computer or the like, and a control engine that controls the printer engine unit It is composed of a circuit board, an input unit for inputting a key operation signal input by operating the operation panel and a print data signal from an external device, and a lithium ion battery for supplying power as a drive source. There is a line printer.

  The printer engine unit is driven by an energization pulse supplied from the lithium ion battery, and is a line dot type thermal head that performs printing on printing paper, and a motor that moves the thermal head, feeds printing paper, and the like. The motor unit includes a motor drive circuit that controls the operation of the motor, and a temperature sensor such as a thermistor that measures the environmental temperature of the thermal head.

  The control circuit board includes a CPU (Central Processing Unit) that controls the entire printer in accordance with a signal from the input unit, a ROM (Read Only Memory) that stores programs executed by the CPU, parameters, and the like, and print data. RAM (Random Access Memory) that temporarily stores control constants, a voltage measurement circuit that measures the output voltage of the lithium ion battery, and a print control circuit that controls the thermal head as a printing unit An environmental temperature measurement circuit for measuring the temperature in the vicinity of the thermal head and the lithium ion battery, an I / O port for transmitting and receiving data to and from a personal computer, and the lithium ion battery as a drive source are connected to an AC And a battery charging circuit for charging using an adapter or the like. The battery charging circuit includes a charging status notifying unit for detecting that the lithium ion battery is fully charged.

  The lithium ion battery can apply a voltage of 4.2 to 8.5 V to the thermal head via a DC / DC converter. The lithium ion battery has an initial capacity (battery capacity immediately after charging). ) Is about 1350 mAh, and its battery capacity is charged by an AC adapter or the like connected to the battery charging circuit.

  In the line printer having such a configuration, the remaining capacity of the lithium ion battery is calculated in each operation.

  First, an AC adapter or the like is connected to the battery charging circuit, and the lithium ion battery is fully charged. Then, the printing process is started after confirming that the lithium ion battery is completely charged by the detection signal from the charging state notifying means. The remaining capacity value of the lithium ion battery at this time is 1350 mAh, which is set as the initial battery capacity.

  Next, print data transmitted from an external personal computer or the like is received, and the process waits until it is determined that a print request has been made. When it is determined that a print request has been made, print processing is performed based on the print request.

  Then, the current value applied to the thermal head is calculated when performing printing processing for one line based on the printing data. Since the number of dots to be printed differs for each line, the current that flows even if the output voltage of the lithium ion battery is the same. Is different for each line printing process, the current value to be applied is calculated every time one line printing process is performed.

  Next, the optimum energization pulse width for printing is calculated based on the output voltage of the lithium battery, etc., and it is consumed when printing one line from the current value applied to the thermal head and the energization pulse width. To calculate the current consumption.

  Thereafter, the remaining capacity of the lithium ion battery after printing is calculated from the current consumption accompanying the printing process for one line and the battery capacity before printing.

  Next, based on the environmental temperature of the printer measured by the environmental temperature measurement circuit, the terminal voltage of the thermal head and the lithium ion battery is detected to correct the current capacity value, and the battery is printed after printing from the calculated remaining battery capacity. It is determined whether or not the capacity remains. When the battery capacity remains, the printing process for one dot line is continued, and when it is determined that the battery capacity does not remain, the printing process ends.

  From the configuration described above, in a line printer as an example of an electric device using a conventional battery as a driving source, the current consumption when printing one dot line is calculated in advance, and the battery capacity performs the printing process. Therefore, it is possible to solve the problem that the battery runs out during printing of one line and the printing process is interrupted or stopped. In addition, since the remaining battery capacity is calculated based on the current consumption, the battery capacity can be managed regardless of the battery discharge characteristics, and the battery charging time can be accurately known. (For example, refer to Patent Document 1).

JP 2003-80758 A

  However, in the line printer using the conventional battery as the driving source as described above, the battery used is a lithium ion battery which is one of the secondary batteries, and it is assumed that the lithium ion battery is fully charged with a battery capacity of 1350 mAh. For example, there is a problem that it is impossible to cope with a case where a primary battery such as an alkaline battery is used.

  Therefore, the present invention can use either a primary battery or a secondary battery as a drive source, and efficiently consumes the battery capacity according to changes in the environmental temperature to maximize the remaining battery capacity. It is an object of the present invention to provide a voltage drop detection method and apparatus in a line printer that can be used as much as possible.

  In order to achieve the above-mentioned object, a characteristic of the voltage drop detection method in the line printer according to the present invention is a voltage drop detection method in a line printer using a battery as a drive source, and the terminal voltage and operation when the battery is not operating The terminal voltage at the time is detected, the discharge characteristic of the battery is calculated from the difference between the terminal voltage at the time of non-operation and the terminal voltage at the time of operation, and the stored discharge characteristics of the primary battery and the secondary battery are referred to. The battery is discriminated and the detection value of the end voltage is selectively changed according to the type of the battery.

  In addition, the environmental temperature is detected, the temperature of the battery is calculated from the environmental temperature, and the detection value of the end voltage is selectively set from the detection value of the end voltage stored according to the temperature of the battery. .

  In addition, a characteristic of the voltage drop detection device in the line printer according to the present invention is a voltage drop detection device in a line printer using a battery as a drive source, the terminal voltage detection means for detecting the battery terminal voltage, and the line printer. A control unit that controls the discharge characteristics of the primary battery and the secondary battery provided in the control unit, and a ROM that stores detected values of the end voltage, respectively, as a table. The terminal voltage detection means detects the terminal voltage during non-operation of the battery and the terminal voltage during operation, and calculates the discharge characteristics of the battery from the difference between the terminal voltage during non-operation and the terminal voltage during operation. The battery is discriminated with reference to the discharge characteristics of the primary battery and the secondary battery stored in the ROM, and the detection value of the end voltage is selectively changed according to the type of the battery. Lies in the fact that is.

  In addition, a temperature sensor for detecting the environmental temperature is provided, and a detection value of the end voltage corresponding to the temperature of the battery is stored as a table in the ROM, and the control unit is configured to calculate the environmental temperature from the environmental temperature detected by the temperature sensor. The temperature of the battery is calculated, and the detection value of the end voltage is selectively set from the detection value of the end voltage stored in the ROM according to the temperature of the battery.

  According to the reduced voltage detection method for a line printer of the present invention, the discharge characteristic of a battery connected to the line printer can be calculated, and whether the battery is a primary battery or a secondary battery can be calculated from the discharge characteristic. Can be determined.

  Then, by selectively changing the detection value of the end voltage according to the determined battery type, both the primary battery and the secondary battery can be used for the line printer.

  Furthermore, by selectively setting the detection value of the end voltage according to the change in the output voltage due to the battery temperature change, the battery capacity can be used to the maximum according to the battery temperature change.

  Further, according to the reduced voltage detection device in the line printer of the present invention, the terminal voltage during non-operation and the terminal voltage during operation are detected, and the discharge characteristic of the battery connected to the line printer is calculated from the difference. It is possible to determine whether the battery connected to the line printer is a primary battery or a secondary battery by referring to the discharge characteristics of the primary battery and the secondary battery stored in the ROM from the discharge characteristics. be able to.

  Then, by selectively changing the detection value of the end voltage stored as a table in the ROM according to the determined battery type, both the primary battery or the secondary battery can be used for the line printer. .

  In addition, the battery temperature is calculated from the environmental temperature, and the detection voltage of the end voltage is selectively set according to the change in the output voltage due to the change in the battery temperature, thereby maximizing the battery capacity according to the battery temperature change. Can be used for

  Hereinafter, embodiments of a reduced voltage detection method and apparatus in a line printer of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing the configuration of the line printer of this embodiment.

  As shown in FIG. 1, the line printer 1 according to the present embodiment executes printing by a control unit 2 that controls printing based on print data output from a personal computer or the like, and a control signal from the control unit 2. In the line printer 1, four batteries 4 are connected in series and stored as a power source for supplying power to the control unit 2 and the printing unit 3. It has become.

  The control unit 2 temporarily stores a CPU 5 that controls the entire line printer 1, a ROM 6 that stores programs and parameters executed by the CPU 5, and print data output from a personal computer or the like. The RAM 7 has terminal voltage detection means 8 for detecting the total output voltage of the four batteries 4 connected in series, and a temperature sensor 9 such as a thermistor for detecting the environmental temperature. In the present embodiment, an A / D converter is used as the terminal voltage detection means 8.

  The ROM 6 stores, as a table, discharge characteristics of a primary battery such as an alkaline battery and a secondary battery such as a nickel metal hydride battery, and a detection value of a final voltage corresponding to a temperature change. The detection value of the end voltage is determined in a range in which the driving of the line printer 1 is guaranteed according to each environmental temperature.

When the battery 4 is an alkaline battery, the nominal voltage of the alkaline battery is 1.5V, the internal resistance is 0.3Ω (approximate value), and in the present embodiment, the four batteries 4 are connected in series. Because it is used, the voltage across the battery during non-operation is 6.0V and the internal resistance is 1.2Ω. Therefore, the relationship between the load current and the terminal current is the terminal voltage (V) = 6.0 (V) − (Load current (A) x 1.2 (Ω))
It becomes. In the present embodiment, the detected value of the end voltage according to the environmental temperature when an alkaline battery is used as the battery 4 is 4.5 V when the temperature of the battery 4 is 0 ° C. or higher and lower than 5 ° C. 4.3 V when 5 ° C. or higher and lower than 15 ° C., 4.2 V when 15 ° C. or higher and lower than 25 ° C., 4.1 V when 25 ° C. or higher and lower than 35 ° C., and 4. V when 35 ° C. or higher and lower than 45 ° C. It is 0V. When the temperature of the battery 4 is lower than 0 ° C., the discharge characteristics of the battery 4 are remarkably deteriorated. When the temperature is 45 ° C. or higher, the battery 4 is greatly deteriorated. Therefore, regardless of the output voltage of the battery 4 The operation of the line printer 1 is stopped.

Further, when the battery 4 is a nickel metal hydride battery, the nominal voltage of the nickel metal hydride battery is 1.2 V and the internal resistance is 0.03Ω (approximate value). In the present embodiment, four batteries 4 are connected in series. The voltage across the battery during non-operation is 4.8V and the internal resistance is 0.12Ω, so the relationship between the load current and the terminal current is the terminal voltage (V) = 4.8. (V)-(Load current (A) x 0.12 (Ω))
It becomes. In this embodiment, when the nickel hydride battery is used as the battery 4, the detected value of the end voltage according to the environmental temperature is 4.4 V when the temperature of the battery 4 is 0 ° C. or more and less than 5 ° C. 4.35V when 5 ° C or more and less than 15 ° C, 4.3V when 15 ° C or more and less than 25 ° C, 4.25V when 25 ° C or more and less than 35 ° C, 4 when 35 ° C or more and less than 45 ° C .2V. As in the case of an alkaline battery, when the temperature of the battery 4 is less than 0 ° C., the discharge characteristics of the battery 4 are remarkably reduced, and when the temperature is 45 ° C. or higher, the battery 4 is severely deteriorated. The operation of the line printer 1 is stopped regardless of the output voltage of the battery 4.

  The printing unit 3 includes a line dot thermal head 10, a motor 11 for generating heat of the thermal head 10 and transporting printing paper (not shown) according to a control signal from the CPU 5 of the control unit 2, And a temperature sensor 12 such as a thermistor for detecting the temperature of the thermal head 10.

  Next, a description will be given of a reduced voltage detection method using the reduced voltage detection device in the line printer of this embodiment in the line printer 1 having such a configuration.

  First, four batteries 4 are connected in series to the line printer 1 as a power source, and the terminal voltage when the four batteries 4 connected in series by the terminal voltage detection means 8 are not operated is detected and stored in the RAM 7. .

  Next, terminal voltages during operation of the four batteries 4 connected in series are detected, and the detected values are stored in the RAM 7. In the present embodiment, the operation time is an initialization operation that does not generate the maximum load in the line printer 1 or a load when the motor 11 of the printing unit 3 is driven in the paper feeding operation.

  Then, the CPU 5 detects the discharge characteristics (reduced voltage values) of the four batteries 4 connected in series from the difference between the non-operating terminal voltage and the operating terminal voltage stored in the RAM 7 and stores them in the ROM 6. The four batteries 4 are discriminated with reference to the discharge characteristics of the primary battery and the secondary battery, and the detection value of the end voltage is determined. At this time, when the environmental temperature that guarantees the operation of the line printer 1 is 0 ° C. or higher, the detection value of the end voltage is set to 4.5 V when the battery 4 is a primary battery, and the battery 4 is a secondary battery. Is set to 4.4V.

  Next, the environmental temperature is detected by the temperature sensor 9 and stored in the RAM 7. And since the temperature of each battery 4 is about 5 degreeC higher than the environmental temperature detected by the said temperature sensor 9, the temperature of each battery 4 is calculated by carrying out correction | amendment calculation of the environmental temperature stored in RAM7 in CPU5. The detection value of the end voltage corresponding to the temperature change stored in the ROM 6 from the temperature of each battery 4 is selectively set.

  From such a configuration, according to the reduced voltage detection method in the line printer of this embodiment, it is determined from the discharge characteristics whether the battery 4 connected to and stored in the line printer 1 is a primary battery or a secondary battery. In addition, it is possible to use either a primary battery or a secondary battery as a drive source of the line printer 1 by selectively setting a detection value of the end voltage of the battery 4 according to a temperature change. In addition, the usable capacity of the battery 4 can be used to the maximum according to the change in the discharge characteristics due to the temperature change of the battery 4. And since the usable quantity of the battery 4 can be used to the maximum, the amount of discarded batteries used in the line printer 1 can be reduced, and the cost can be reduced.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed. For example, in the present embodiment, the temperature sensor 9 that detects the environmental temperature and the temperature sensor 12 that detects the temperature of the thermal head 10 are provided, but the environmental temperature and the temperature of the thermal head 10 are controlled by one temperature sensor. It is also possible to detect.

Block diagram showing the configuration of the line printer of the present embodiment

Explanation of symbols

1 Line Printer 2 Control Unit 3 Printing Unit 4 Battery 5 CPU
6 ROM
7 RAM
8 Terminal voltage detection means 9 Temperature sensor 10 Thermal head 11 Motor 12 Temperature sensor

Claims (4)

  A voltage drop detection method for a line printer using a battery as a driving source, wherein the terminal voltage when the battery is not operating and the terminal voltage when the battery is operating are detected, and the terminal voltage when the battery is not operating and the terminal voltage when the battery is operating The battery is determined by referring to the stored discharge characteristics of the primary battery and the secondary battery by calculating the discharge characteristics of the battery from the difference between them, and the end voltage is selectively selected according to the type of the battery. A method of detecting a reduced voltage in a line printer, wherein the detection value is changed.   An environmental temperature is detected, the temperature of the battery is calculated from the environmental temperature, and a detection value of the end voltage is selectively set from a detection value of the end voltage stored according to the temperature of the battery. The method of detecting a reduced voltage in the line printer according to claim 1.   A voltage drop detection device for a line printer using a battery as a driving source, a terminal voltage detecting means for detecting a terminal voltage of the battery, a control unit for controlling the line printer, and a primary provided in the control unit And a ROM in which discharge characteristics of the battery and the secondary battery and detection values of the end voltage are stored as a table, respectively, and the control unit detects the terminal voltage when the battery is not operating and the operating time by the terminal voltage detecting means. Terminal voltage is detected, the discharge characteristics of the battery are calculated from the difference between the non-operating terminal voltage and the operating terminal voltage, and the discharge characteristics of the primary battery and the secondary battery stored in the ROM are referred to. The voltage drop detecting device in the line printer is characterized in that the battery is discriminated and the detection value of the end voltage is selectively changed according to the type of the battery.   A temperature sensor for detecting an environmental temperature is provided, and a detection value of an end voltage corresponding to the temperature of the battery is stored as a table in the ROM, and the control unit is configured to store the battery voltage based on the environmental temperature detected by the temperature sensor. The temperature is calculated, and the detection value of the end voltage is selectively set from the detection value of the end voltage stored in the ROM according to the temperature of the battery. Voltage drop detection device for line printers.