JPH08115147A - Power supply discriminating device and printer - Google Patents

Abstract

PURPOSE: To provide a power supply discriminating device capable of discriminating the sorts of power supplies including batteries by using a voltage drop difference generated due to internal resistor specific in the sort of a battery and a printer including the discriminating device in its inside. CONSTITUTION: The power supply discriminating device for discriminating the sort of a power supply by the use of a power supply terminal 11, a low resistor (dummy resistor) 12, a transistor(TR) 13 for turning on/off a current allowed to flow into the low resistor 12, a voltage detecting device 18, an IC memory (RAM) 16 for storing a voltage value, and a CPU 17 for discriminating the sort of a battery is built in the printer and the applying time of a head is changed in accordance with the sort of the power supply. Thereby always stable printing quality can be obtained independently of the sort of a power supply by changing the applying time of the head in accordance with the sort.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply discriminating device and a printing device for equipment using a battery and an AC power supply.

[0002]

2. Description of the Related Art In recent years, portable devices have been downsized,
There is an increasing demand for portable devices that can be AC-driven and battery-driven at the same time. Along with this, the demand for portable printing devices is also increasing. Above all, a small wire dot printer is required because of its low power consumption and easy miniaturization.

A power supply device for a conventional wire dot printer will be described below. FIG. 6 is a block diagram of a power supply device of a conventional wire dot printer. In the figure, 1 is a power supply terminal, 2 is a coil for driving a wire (hereinafter referred to as a head coil), 3 is a head coil 2 ON / OFF
A driver 4 for performing printing is an arithmetic unit (hereinafter, referred to as a CPU) for controlling printing. The wire dot printer drives a wire by electromagnetic force and hits the paper with the wire over the ribbon to perform printing. Therefore, in order to maintain stable print quality, the current flowing through the head coil 2 needs to be always constant in order to keep the electromagnetic force that generates the driving force of the wire constant.

[0004]

However, in the above-mentioned conventional configuration, when the power source is changed to AC power source, NiCd battery, alkaline dry battery, manganese dry battery, etc., the current supply capability is different depending on the type of power supply. Since the resistance of the wire driving coil is constant, the expected current value may not be obtained, or a current higher than expected may flow. As a result, printing scrapes due to insufficient printing power, wire penetration into the ribbon due to excessive printing power, etc. occur, limiting the usable power source (battery). When the power supply changes as described above, the amount of current that can be supplied also changes accordingly. Therefore, in order to stabilize the print quality, the type of power supply is determined when printing, and the printing pressure, that is, the head It is necessary to change the time.

Therefore, an object of the present invention is to provide a power supply discriminating apparatus and a printing apparatus which discriminate the type of a power source including a battery by utilizing the difference in voltage drop caused by the internal resistance peculiar to the battery type.

[0006]

To this end, the present invention provides a power supply, a low resistance connected to the power supply via a switch, and a means for measuring the voltage across the low resistance when the switch is on and off. A first storage means for storing the voltage value measured by the means for measuring the voltage, a second storage means for storing the program and data, and a first storage means. The power supply discriminating device is constituted by the potential difference between the voltage across the low resistance when the switch is ON and when the switch is OFF, and the arithmetic unit which discriminates the type of the power supply based on the data stored in the second storage means.

Further, a power supply discriminating device, a wire for printing, a coil for generating an electromagnetic force for driving the wire, and a current flowing through the coil are turned ON / OFF.
The printer is composed of a driver for doing this.

[0008]

According to the above construction, by discriminating the type of the power source and changing the application time of the head voltage in accordance with the type, it is possible to always secure stable printing quality regardless of the type of the power source.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a power supply device for a wire dot printer according to a first embodiment of the present invention, and FIG. 2 is a graph showing different voltage drops depending on the power supply of the wire dot printer. In FIG. 1, 11 is a power supply terminal portion, 12 is a low resistance (hereinafter, referred to as a dummy resistance), 13 is a switch (hereinafter, referred to as a transistor) for turning on / off a current flowing through the dummy resistance 12, and 14 is a wire. A coil for driving the head coil (hereinafter referred to as a head coil), a driver 15 for turning on / off the head coil 14, and a driver 16
Is an IC memory (hereinafter referred to as RAM) that stores a voltage value, 17 is an arithmetic unit (hereinafter referred to as CPU) for determining the power supply type, 18 is a voltage detection device that detects the voltage value, and 19 is a power supply type This is a memory (hereinafter referred to as a ROM) that stores the data required to determine the ON time and the ON time of the driver 15 according to the power source type.

In FIG. 2, when the transistor 13 is turned on, a current flows through the low resistance 12. If the resistance value of the low resistance 12 is sufficiently small, the voltage when the transistor 13 is turned on and the voltage when the transistor 13 is turned off differ depending on the current supply capability of the power supply. Although almost no voltage drop occurs when an AC power source is used, when a battery is used, a constant voltage drop occurs depending on the type because the battery has a specific internal resistance depending on the type. The internal resistance of the batteries is in the order of NiCd battery <Alkaline battery <Mn battery, and it is almost the same for batteries of the same type. Therefore, in the figure, A is a voltage drop when an AC power source is used, V1 is a voltage drop value at that time, B is a voltage drop when a nickel cadmium battery is used, V
2 is a voltage drop value at that time, C is a voltage drop value when an alkaline dry battery is used, V3 is a voltage drop value at that time, D is a voltage drop value when a manganese dry battery is used, and V4 is a voltage drop value at that time. The values of these voltage drop values V1 to V4 are stored in the ROM 19 in advance.

FIG. 3 is a flow chart for determining the power source of the wire dot printer according to the first embodiment of the present invention. First, using the voltage detection device 18, the transistor 13
The voltage when OFF is measured (step 1), and the result is stored in the RAM 16 (step 2). The transistor 13 is turned on to allow a current to flow through the dummy resistor 12, and the voltage at that time is measured using the voltage detection device 18 and stored in the RAM 16 (steps 3 and 4). Next, the potential difference between the voltage value when the transistor 13 stored in the RAM 16 is OFF and the voltage value when a current is passed through the dummy resistor 12 is CP.
The calculation is performed in U17, and the result is compared with the data stored in the ROM 19 by the CPU 17 (step 5). If the value of the potential difference is V1, it is an AC power source, if it is V2, it is a nicad battery, V3. If it is an alkaline dry cell, and if it is V4, a manganese dry cell and the type of power source can be discriminated (step 6).

Next, a second embodiment of the present invention will be described. FIG. 4 is a flow chart of determining the power source of the wire dot printer of the second embodiment of the present invention and starting printing. The structure of the apparatus is the same as that of the first embodiment shown in FIG.

When a print start command is sent to the CPU 17 (step 11), the voltage detection device 18 is first used to measure the voltage when the transistor 3 is OFF (step 1).
2), the result is stored in the RAM 16 (step 1)
3). Next, the transistor 13 is turned on and the dummy resistor 1
A current is passed through 2, and the voltage at that time is measured using the voltage detection device 18 and stored in the RAM 16 (steps 14, 1).
5). Next, the transistor 1 storing the RAM 16
The CPU 17 calculates the potential difference between the voltage value when 3 is OFF and the voltage value when a current is passed through the dummy resistor 12, and the CPU 17 compares the result with the data stored in the ROM 19. , If the value of the potential difference is V1, AC
The type of power source is determined as a power source, a nickel-cadmium battery if V2, an alkaline dry battery if V3, a manganese dry battery if V4 (steps 16 and 17). Therefore, RO
The ON time of the driver 15 according to the power supply capability of each power source is stored in M19, and the CPU 1 is set to the ON time of the driver 15 according to the power supply device determined by the power supply determination device.
7 and start printing (steps 18 and 1)
9).

Next, a third embodiment of the present invention will be described. FIG. 5 is a flowchart up to the start of printing when a head coil is used instead of a low resistance when determining the power source of the wire dot printer of the third embodiment of the present invention. The structure of the apparatus is the same as that of the first embodiment shown in FIG. When the CPU 17 receives a command to start printing (step 21), the initial voltage is first measured using the voltage detection device 18 (step 22), and the result is stored in the RAM 16 (step 23). Next, the driver 15 is turned on for a certain period of time to pass a current through the head coil 14, and the voltage at that time is measured using the voltage detection device 18 and stored in the RAM 16 (steps 24 and 25). Next, the CPU 17 calculates the potential difference between the voltage value when the transistor 13 stored in the RAM 16 is OFF and the voltage value when the current is applied to the head coil 14, and the result is stored in the ROM 19. The CPU 17 compares the data with the current data, and if the value of the potential difference is V1, the AC power source, if it is V2, the nicad battery, if it is V3, the alkaline battery, if it is V4, the manganese battery and the type of the power source are determined ( Steps 26 and 2
7). Therefore, the ON time of the driver 15 is set in advance in the ROM 19 according to the power supply capacity of each power source, and the driver 1 corresponding to the power supply device determined by the power supply determination device is set.
The ON time of 5 is set by the CPU 17 and printing is started (steps 28 and 29).

[0015]

As described above, according to the present invention, it becomes possible to discriminate the type of power source with an inexpensive circuit.
In particular, by determining the type of power supply using the circuit and changing the print time of the head according to the type, it is possible to always obtain stable print quality regardless of the type of power supply.

[Brief description of drawings]

FIG. 1 is a block diagram of a power supply device for a wire dot printer according to a first embodiment of the present invention.

FIG. 2 is a graph showing different voltage drops depending on the power source of the wire dot printer according to the first embodiment of the present invention.

FIG. 3 is a flowchart for determining the power source of the wire dot printer of the first embodiment of the present invention.

FIG. 4 is a flowchart for determining the power source of the wire dot printer of the second embodiment of the present invention and starting printing.

FIG. 5 is a flowchart up to the start of printing when a head coil is used instead of low resistance when determining the power source of the wire dot printer of the third embodiment of the present invention.

FIG. 6 is a block diagram of a power supply device of a conventional wire dot printer.

[Explanation of symbols]

 11 Power Supply Terminal Section 12 Low Resistance (Dummy Resistance) 13 Transistor 14 Wire Driving Coil (Head Coil) 15 Driver 16 IC Memory (RAM) 17 Arithmetic Unit (CPU) 18 Voltage Detection Device 19 Data Storage Device (ROM)

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Claims (3)

[Claims] 1. A power supply, a low resistance connected to the power supply via a switch, means for measuring the voltage across the low resistance when the switch is on and off, and means for measuring the voltage. A first storage means for storing the measured voltage value and a second storage means for storing the program and data.
Of the power source based on the potential difference between the voltage across the low resistance when the switch is turned on and when the switch is turned on, and the data stored in the second storage means. A power supply discriminating device comprising: an arithmetic unit for discriminating a type. 2. A power supply, a low resistance connected to the power supply via a switch, a means for measuring the voltage across the low resistance when the switch is on and off, and a means for measuring the voltage. A first storage means for storing the measured voltage value and a second storage means for storing the program and data.
Of the power source based on the potential difference between the voltage across the low resistance when the switch is turned on and when the switch is turned on, and the data stored in the second storage means. In order to turn on / off a power supply discriminating device including a calculation unit for discriminating a type, a wire for printing, a coil for generating an electromagnetic force for driving the wire, and a current flowing through the coil. And a driver for the printer. 3. The printing apparatus according to claim 2, further comprising a power supply discriminating device having a means for turning on a coil for driving the wire for a predetermined time instead of a low resistance.