JP2002059622A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the lifetime of a battery by reducing loss. SOLUTION: A relay 20 has an ON terminal being supplied with a power supply voltage from a terminal 16 connected with the positive polarity end of an AC adapter 3 and an OFF terminal being supplied with a power supply voltage from a terminal 19 connected with the positive polarity end of a battery 21. An input voltage decision circuit 25 generates an ON signal when the AC adapter 3 is connected and generates an OFF signal when the AC adapter 3 is removed. When the AC adapter 3 is connected, the relay 20 selects a power supply input from the AC adapter 3 preferentially in response to an ON signal from the input voltage decision circuit 25. Since no diode is employed in the selection of power supply input and no element causing a voltage drop is present in the current path to a thermal head, lifetime of the battery can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a printer device such as a sublimation type thermal transfer printer and a printing method thereof.

[0002]

2. Description of the Related Art In recent years, as a device for hard copying an image from a personal computer, a camera-integrated video tape recorder, an electronic still camera, or the like, a thermal transfer printer device capable of displaying a high-definition image by full color has been developed. It is becoming popular.

In a conventional thermal transfer type printer, a recording sheet is pressed and held between a platen roller and a thermal head together with an ink sheet. The ink sheet is obtained by applying a thermo-sublimable dye to a base film, and is arranged such that the thermo-sublimable dye is pressed against recording paper. Multiple heating elements are provided on one side of the thermal head,
By energizing the thermal head, these heating elements appropriately generate heat according to print data, and heat the heat sublimable dye via the base film. Thereby, the heat sublimable dye sublimates and is transferred and recorded on the recording paper.

When a printer is to be carried, it is necessary to improve its usefulness by making it operable even in a place where there is no AC power supply. That is, a portable printer needs to be drivable using only a battery (battery) as a power source. Moreover, when portability is emphasized, a relatively small battery capacity is adopted.

[0005] The battery is consumed when used, and the supply voltage gradually decreases in accordance with the degree of consumption.
Therefore, even in a portable printer, when the AC power can be used, it is better to use the AC power instead of the battery in order to suppress the consumption of the battery. Can be achieved. Therefore, generally, use of the AC power supply is prioritized, and when the connector of the AC power supply is connected, switching from the battery to the AC power supply is automatically performed.

[0006] The printing density on recording paper is determined by the temperature of the heating element. That is, the print density can be easily changed by changing the amount of current supplied to the heating element of the thermal head. As a method of changing the amount of current flowing through the heating element, a method of changing the time during which current is passed through the heating element (hereinafter, referred to as energization time) is employed.

The control of the power supply time is performed by a CPU built in the apparatus. At the time of power supply using an AC power supply, a relatively stable power supply voltage can be obtained, so that the CPU can perform energization control without considering the fluctuation of the power supply voltage. On the other hand, when the battery is used, the power supply voltage to be supplied changes according to the degree of exhaustion. Therefore, the CPU needs to monitor the supply voltage and correct the power-on time according to the monitoring result.

Generally, a power supply switching circuit using a diode is used for switching between a DC output using an AC power supply and a DC output from a battery. Diodes are arranged at the output terminal of the DC output using the AC power supply and the output terminal of the DC output from the battery, and the anodes of the diodes are connected to each other to take out the DC output having a higher DC output level. . However, such power supply selection is based on the premise that the DC output from the AC power supply is larger than the DC output from the battery. However, when the print density is constant between when the AC power supply is used and when the battery power supply is used, it is necessary to make the DC output from the AC power supply substantially equal to the DC output from the battery. Can not be adopted.

In view of this, a power supply switching circuit that switches between DC output from an AC power supply and DC output from a battery using an FET as a switching element may be employed. However, even when an FET is used, it is necessary to arrange diodes at the output terminal of the DC output by the AC power supply and the output terminal of the DC output by the battery power supply in order to prevent the backflow of current.

That is, in the power supply switching circuit, diodes are arranged at each output terminal. However, a loss occurs due to the voltage drop of the forward voltage VF of the diode. When a large current flows, such as when driving a thermal head,
This forward voltage VF increases and the loss becomes extremely large.

[0011]

As described above, in the conventional printer, since the diode is used for switching the power supply input, there is a problem that the loss is large and the battery life is disadvantageous. .

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to provide a printer device that can extend the life of a battery by using a relay for switching power input. .

[0013]

A printer apparatus according to the present invention has a thermal head for printing an image based on image data on paper, a power supply from a battery power supply, and a voltage substantially equal to a voltage of the battery power supply. And a power supply switching means for selectively switching the power input from the AC adapter means for supplying the power of the voltage by a relay and applying the power to the thermal head.

In the present invention, the power supply switching means supplies power to the thermal head by selectively switching power input from the battery power supply means and power input from the AC adapter means by a relay.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows the first embodiment of the present invention.
FIG. 4 is a circuit diagram showing a power supply switching circuit portion employed in the printer device according to the embodiment. FIGS. 2 and 3 are explanatory views showing the external appearance of the apparatus and the AC adapter.

In FIG. 2, the printer housing 1 incorporates the power supply switching circuit unit of FIG. 1, a recording paper transport mechanism (not shown), a thermal head, a power supply board, a control board, and the like.
In a thermal head (not shown), a plurality of heating elements constituting each dot are arranged. During printing, the thermal head sandwiches a recording paper and an ink sheet (not shown) and is pressed against a platen roller (not shown). The heating element is pressed against the recording paper via the ink sheet.

Each heating element generates heat when supplied with a power supply voltage from a power supply control unit 27 shown in FIG. 1 described later. Each of the plurality of heating elements is provided with a switching element (not shown), and the supply of the power supply voltage to the heating element is controlled by turning on and off the switching element. That is, the heating element generates heat when energized, and heats and sublimates the heat sublimable dye on the ink sheet to transfer and record it on recording paper.

A power supply voltage from the AC adapter 3 or the battery 21 is supplied to a power supply control section 27 formed on a power supply board. In FIG. 2, a connector 2 is provided on a printer housing 1, and a plug 4 of an AC adapter 3 can be inserted into the connector 2. The AC adapter 3 is supplied with a commercial power supply voltage by inserting a plug 5 into a commercial power supply outlet (not shown), and generates a DC voltage. The power supply voltage generated by the AC adapter 3 is supplied from the plug 4 to the connector 2.

In FIG. 1, one terminal 15 of the connector 2
Is connected to the reference potential point, and the other terminal 16 is connected to the ON terminal of the relay 20. On the other hand, a battery section 17 (not shown in FIG. 2) is exposed in the printer housing 1. A battery 21 can be mounted on the battery section 17. Thereby, the negative terminal of the battery 21 is connected to the terminal 18 of the battery piece 17, and the positive terminal of the battery 21 is connected to the terminal 19. The terminal 18 of the battery section 17 is connected to the reference potential point, and the terminal 19 is connected to the relay 20.
Connected to the OFF terminal.

A DC voltage from the AC adapter 3 or a DC voltage from the battery 21 is supplied to the ON terminal or the OFF terminal of the relay 20, respectively.
A DC voltage at the ON terminal or the OFF terminal of the relay 20 is applied to generate a power supply voltage required for each unit.

In the present embodiment, the power supply voltage applied to the thermal head from the power supply control unit 27 is set to a relatively low voltage, for example, 7.2 V, and the resistance value of the heating element is set to a relatively small value, for example, 660 Ω to 750 Ω. Is set to.

In a printer, how to set E, which is the maximum density at the time of printing, and how long the overcharge time to the head is an important issue. The maximum density E is predetermined as a certain constant value.

If the energizing time is lengthened, a sufficient printing density can be obtained even if the current flowing through the heating element is reduced, but the printing time becomes longer. In the case of a color printer, the printing operation is performed for each of the four color inks of, for example, Y, M, C, and BK. Therefore, the printing operation is performed four times. It cannot be adopted because it would increase the time and impair the practicality. For this reason, in the present embodiment, the amount of current flowing through the heating element is increased in order to set a shorter energization time. Since the amount of current flowing through the heating element is increased, no diode or the like that causes a voltage drop is provided on the current path. That is, in the present embodiment, the relay 20 is employed as the power supply switching circuit without employing a configuration using a diode or an FET.

Further, a DC-DC converter is not used in consideration of portability. That is, in the present embodiment, the power supply voltage from the battery 21 is directly applied to the heating element without being boosted. Therefore, a battery that can generate a power supply voltage to be supplied to the thermal head is used as the battery 21. For example, a nickel hydride secondary battery having a large current capacity is used as the battery 21. For example,
Each cell is composed of six 1.2 V nickel-metal hydride batteries connected in series to form a 7.2 V battery 21. As a result, the battery 21 can be made relatively small, and the portability of the device can be satisfied.

The lithium ion secondary battery has a high voltage per cell of 3.6 V, which is advantageous for carrying. However, since the internal resistance is large and the current that can be taken out per time is small, a thermal current requiring a large current is required. Not suitable for head.

By appropriately setting the resistance value of the heating element, even when the power supply voltage is as low as 7.2 V, a sufficient current is supplied to the heating element to enable printing with a reduced energization time. That is, in a general printer in which the energization time is shortened, a heater of 7 kΩ is used as a heating element.
Some apply a voltage of 2 V, and others apply a voltage of 28 V using a heating element of 10 kΩ. In the present embodiment, the setting is made such that the amount of energy applied to the thermal head is equivalent to that of a general printer in which the power supply time is reduced. That is, as described above, if a voltage of 7.2 V is applied to the heating element,
The resistance value is set, for example, to 660Ω to 750Ω.

In order to match the print quality when using the battery 21 and when using the AC adapter 3, the AC adapter 3 is used.
The DC voltage value generated by the battery 21 is made to match the voltage that can be generated by the battery 21. That is, A
Since the DC voltage of the C adapter 3 and the DC voltage of the battery 21 substantially match, the relay 20 is used in this embodiment also without using a diode as a power supply switching circuit.

In FIG. 1, the voltage at the terminal 19 of the battery section 17 is supplied to the control terminal of the battery loading switch 22. The battery loading switch 22 is turned on only when the battery 21 is mounted on the battery section 17 and the power supply voltage of the battery 21 is supplied to the control terminal, and supplies a mounting signal to the control circuit 23.

The control circuit 23 controls each unit such as a power supply board (not shown) and a circuit unit on the control board. Further, the control circuit 23 outputs to the permission / prohibition circuit 26 a power supply switching prohibition signal for prohibiting switching between the use of the AC power supply and the use of the battery 21 as the power supply.

A power supply voltage of positive polarity is applied to the terminal 16 from the AC adapter 3. The power supply voltage applied to the terminal 16 is not only the ON terminal of the relay 20 but also the reference voltage generation circuit 24. And the input voltage determination circuit 25.

The reference voltage generating circuit 24 is connected to the AC adapter 3
Is connected to the connector 2, a DC voltage is supplied via the terminal 16, a predetermined reference voltage is generated and output to the input voltage determination circuit 25.

The input voltage determination circuit 25 compares the voltage applied to the terminal 16 with a reference voltage. This allows
The input voltage determination circuit 25 determines whether the plug 4 of the AC adapter 3 is connected to the connector 2 and the DC voltage generated by the AC adapter 3 is supplied to the terminal 16 (hereinafter, the case where the AC adapter 3 is connected). ), An ON signal which is a determination result indicating that the power supply voltage is being supplied from the AC adapter 3 is output to the permission / inhibition circuit 26, and A
When the DC voltage from the C adapter 3 is not supplied to the terminal 16 (hereinafter, referred to as the case where the AC adapter 3 is not connected), the determination result indicates that the power supply voltage from the AC adapter 3 is not supplied. An OFF signal is output to the permission / prohibition circuit 26.

The permission / prohibition circuit 26 causes the relay 20 to select an ON terminal by an ON signal from the input voltage determination circuit 25, and causes the relay 20 to select an OFF terminal by an OFF signal. Accordingly, when the AC adapter 3 is connected, the DC voltage from the AC adapter 3 instead of the battery 21 is preferentially supplied to the power control unit 27, and the consumption of the battery 21 is suppressed. .

Incidentally, the AC adapter 3 is, for example, a 7.
A constant voltage such as 2V can be supplied. On the other hand, the supply voltage of the battery 21 gradually decreases from 7.2 V according to the degree of consumption. Therefore, the control circuit 23
Performs a battery check of the battery 21 using a measuring device (not shown), and determines that printing using the battery 21 as a power source is impossible if the voltage is equal to or lower than a predetermined voltage level (for example, 6 V). In this case, the control circuit 23
Displays a warning indicating that the battery capacity is insufficient to the user using a display device or the like (not shown).

However, as a result of the battery check, battery 2
If the supply voltage from 1 is higher than a predetermined voltage level, for example, 6.1 V, printing may be performed. In this case, the control circuit 23 controls the printing time of the thermal head (the time for energizing the heating element) according to the voltage value of the battery 21 to secure a desired printing density.

Even if the printing operation is started in such a setting, if the AC adapter 3 is connected during the printing operation, the input voltage determination circuit 25 outputs an ON signal. If the relay 20 is operated by this ON signal and the power supply voltage from the AC adapter 3 is supplied to the power supply control unit 27, the voltage supplied to the heating element suddenly changes from 6.1V to 7.2V. Resulting in.

In this case, there is no problem if the control circuit 23 changes the control of the energization time in response to the change in the voltage. However, in a color printer of a thermal sublimation type or the like, it is necessary to repeat paper feeding and printing operations four times using inks of four colors of Y, M, C, and BK.
In order for the control circuit 23 to control the energization time in response to a change in voltage, a sequence for monitoring the supply voltage value needs to be performed at an extremely high frequency, which results in an increase in printing time.

For this reason, in the present embodiment,
The control circuit 23 performs the battery check only at the start of the printing operation, and performs the energization control using the check result. That is, the control circuit 23 maintains the setting of the energization control at the start of the printing operation until the end of one printing operation.

In this embodiment, when a DC voltage is supplied from the AC adapter 3 during printing, the printing density is prevented from significantly changing.
Changing the connection state of the relay 20 that supplies the DC voltage to the power supply control unit 27 is prohibited so that the power supply voltage applied to the heating element does not change.

That is, in the present embodiment, the control circuit 23 outputs to the permission / prohibition circuit 26 a power supply switching prohibition signal for prohibiting switching of the power supply to the AC adapter 3 from the start to the end of printing. It is supposed to. The permission / prohibition circuit 26 controls the current state of the relay 20 (when the output of the input voltage determination circuit 25 changes from the OFF signal to the ON signal) when the power supply switching prohibition signal is input by the control circuit 23. (OFF terminal selection).

The AC adapter 3 may be built in the printer case. FIG. 3 is an explanatory view showing the appearance in this case.

In FIG. 3, an AC adapter (not shown) similar to the AC adapter 3 is built in the printer housing 7 in addition to the configuration in the printer housing 1 of FIG. By connecting the plug 11 of the cable 9 to an outlet of a commercial power supply (not shown) and inserting the plug 10 into the connector 8 provided in the printer housing 7, the DC power is supplied from the AC adapter built in the printer housing 7. Voltage can be obtained.

In this case, the positive terminal of the built-in AC adapter is the ON terminal of the relay 20 and the reference voltage generating circuit 2
4 and the input voltage determination circuit 25, and the negative terminal is connected to the reference potential point.

Next, the operation of the embodiment configured as described above will be described with reference to the flowchart of FIG.

When the power is turned on in step S1 of FIG. 4, the control circuit 23 performs a battery check in step S2 prior to printing. Battery 21
Is attached to the battery section 17, the battery loading switch 22
Turns on. Thereby, the control circuit 23 recognizes that the battery 21 is mounted, and executes a battery check. The control circuit 23 measures the output voltage of the battery 21 and
It is determined whether there is sufficient remaining capacity for printing.

If the control circuit 23 determines in the battery check in step S2 that there is not enough remaining capacity in the battery 21 for printing, it indicates in step S7 that the battery capacity is insufficient. Perform display processing or end processing. The control circuit 23
The notification by voice may be performed together with or instead of the display processing.

In step S3, the control circuit 23
Is in a standby state for an input operation for instructing a print start. When a print start instruction is input, the control circuit 2
3 measures a power supply voltage value supplied from the power supply control unit 27. When the power supply voltage is supplied by the AC adapter 3, a sufficient power supply voltage value is always obtained. However, when the power supply voltage is supplied by the battery 21, depending on the degree of consumption of the battery 21, printing may be performed. There may not be enough battery capacity left. If the control circuit 23 determines in step S5 that the remaining capacity of the battery 21 is insufficient, in step S7, it performs a display process indicating that the battery capacity is insufficient or performs an end process. .

On the other hand, when the power supply voltage is supplied from the AC adapter 3 or when the remaining capacity of the battery 21 is sufficient for the printing, the control circuit 23
Various settings such as the energizing time are performed according to the measurement result of the power supply voltage.

When the power supply voltage is supplied from the AC adapter 3 or when the remaining capacity of the battery 21 is sufficient,
In the next step S6, it is determined whether or not the power supply voltage is supplied by the AC adapter 3.

Now, it is assumed that the plug 5 of the AC adapter 3 is connected to the outlet of the commercial power supply, and the plug 4 is connected to the connector 2. In this case, the power supply voltage of the AC adapter 3 is supplied to the ON terminal of the relay 20, and the reference voltage generation circuit 24 and the input voltage determination circuit 25
Is also supplied. The reference voltage generation circuit 24 generates a reference voltage from the output DC voltage of the AC adapter 3, and the input voltage determination circuit 25 receives a power supply voltage from the AC adapter 3 by comparing the reference voltage with the voltage of the terminal 16. It is determined that there is. Thus, the input voltage determination circuit 25
The ON signal is supplied to the relay 20 via the permission / prohibition circuit 26, and the relay 20 supplies the power supply voltage from the AC adapter 3 supplied to the ON terminal to the power supply control unit 27.

The power supply control section 27 supplies a stable power supply voltage of 7.2 V from the AC adapter 3 to the heating element of the thermal head as it is. On the other hand, the control circuit 23
In step S8, the paper is fed. That is, the recording paper is transported until the heating element of the thermal head is pressed against the platen roller with the ink ribbon and the recording paper interposed therebetween.

Next, the control circuit 23 starts printing of the first color in step S9. That is, the control circuit 2
Reference numeral 3 drives a transistor that controls the energization of each heating element based on the print data, and passes a current from the power control unit 27 to the heating element.

A power supply voltage from the power supply control unit 27 is applied to the heating element connected to the turned-on transistor. As a result, the heating element turned on generates heat, and the sublimable dye applied to the ink ribbon is sublimated and transferred to the recording paper. Thus, the heat sublimable dye is transferred at a print density corresponding to the print data.

When printing of a predetermined number of lines in the width direction of the recording paper is performed by the heating element, the recording paper and the ink ribbon are conveyed, and printing of the next predetermined number of lines is performed. Thereafter, similarly, printing by the thermal head and conveyance of the recording paper and the ink ribbon are repeated to perform printing.

When the recording of the first color (for example, cyan) is completed, the control circuit 23 conveys the recording paper to the same position as the recording start position of the first color in step S10. Next, in step S11, the ink ribbon is moved to a position where the transfer of the second color (for example, yellow) is possible,
The printing of the second color is performed in the same manner as the printing of the first color. Thereafter, similarly, printing of each color is performed, and printing is completed (step S12).

In step S22, it is determined whether or not continuous printing has been instructed. If there is continuous printing, the process returns to step S4, and the same processing is repeated. In step S3,
To a standby state for the user's print start operation.

Next, it is assumed that the AC adapter 3 is not connected at the time of the determination in step S6. In this case,
The input voltage determination circuit 25 outputs an OFF signal. This OFF signal is supplied to the relay 20 via the permission / prohibition circuit 26, and the relay 20 selects the OFF terminal.
Thus, in this case, the power supply voltage from the battery 21 is supplied to the power supply control unit 27.

As described above, the input voltage determination circuit 25 determines whether or not the power supply voltage is supplied from the AC adapter 3, and controls the relay 20 according to the determination result to switch the power supply. By DC
Even when the voltage and the DC voltage by the battery 21 are substantially equal,
Power supply switching control is possible.

The power supply control section 27 supplies the power supply voltage of the battery 21 input via the OFF terminal of the relay 20 to the heating element of the thermal head as it is. In this case, since an element such as a diode for lowering the voltage is not interposed in the current path to the heating element, a large current can efficiently flow through the heating element. Thus, even at a relatively low power supply voltage, the resistance value of the heating element can be reduced to allow a large current to flow, thereby shortening the printing time.

If it is determined in step S6 that the AC adapter 3 is not connected, the control circuit 23
Outputs a power switching prohibition signal (step S13). This power switching prohibition signal is supplied to the permission / prohibition circuit 26,
The permission / prohibition circuit 26 stops (fixes) the switching operation of the relay 20. That is, during the output period of the power supply switching inhibition signal,
The power supply voltage from the battery 21 is continuously supplied to the power control unit 27.

Next, the printing process of steps S14 to S18 is performed. The print processing in steps S14 to S18 is the same as the print processing in steps S8 to S12. Next, the determination in step S22 is performed.

As described above, in the present embodiment, even when the AC adapter 3 is connected during printing using the battery 21, the switching operation of the relay 20 is prohibited by the power supply switching prohibition signal. The power supply voltage is prevented from suddenly fluctuating, and the print density is kept constant to prevent the print quality from deteriorating.

FIG. 5 is a flowchart showing an operation flow employed in the second embodiment of the present invention. In FIG. 5, the same steps as those in FIG.

In the first embodiment, when performing continuous printing in which a plurality of printings are continuously performed using a battery as a power supply, printing using the battery is performed until all printing is completed. However, considering the consumption of the battery and the like, it may be better to switch the power supply from the battery to the AC adapter 3 between each printing. The present embodiment is applied to this case.

The hardware configuration of this embodiment is the same as that of FIG.

The processing (steps S1 to S18) from the power-on to the end of one printing operation is the same as in FIG. In the present embodiment, when the printing process for one sheet is completed, the control circuit 23 cancels the output of the power supply switching inhibition signal in step S19. Then, the permission / prohibition circuit 26 outputs the output of the input voltage determination circuit 25 to the relay 20.
To enable the power supply switching operation.

Next, in step S20, the input voltage determination circuit 25 determines whether or not the AC adapter 3 is connected, and if it is, causes the relay 20 to select the ON terminal in step S21. . This allows
In the case where the AC adapter 3 is connected during printing or the like, the power is switched to the AC adapter 3 after the printing operation of one sheet is completed.

In the next step S22, it is determined whether or not continuous printing has been instructed. If there is continuous printing, the process returns to step S4, and the same processing is repeated. If not, the process returns to step S3 to wait for the user to start printing.

As described above, in the present embodiment, the same effects as those of the first embodiment can be obtained, and when continuous printing is instructed, the AC adapter 3 is switched every time one sheet is printed. The connection is enabled, and there is an advantage that the consumption of the battery 21 can be suppressed without deteriorating the print quality.

In the first and second embodiments, power supply switching prohibition control is performed in consideration of the case where the AC adapter 3 is connected during printing using the battery 21. Conversely, the plug 4 of the AC adapter 3 may be disconnected from the connector during printing using the power supply voltage from the AC adapter 3. In this case, relay 2
If the switching of the power supply by 0 is prohibited, the power supply voltage is not supplied to the power supply control unit 27. For this reason, in the first and second embodiments, the power supply switching prohibition signal is not generated during printing using the AC adapter 3.

However, during printing, the AC adapter 3
When the power is switched from the battery to the battery 21, the print density may significantly change. Therefore, during printing, AC
A method of not changing the supply state of the power supply voltage from the adapter 3 is considered.

FIGS. 6 and 7 relate to a third embodiment of the present invention and show a lock mechanism for keeping the supply state of the power supply voltage from the AC adapter 3 from changing.
FIG. 6 is a perspective view showing the configuration of the AC adapter side, and FIG.
FIG. 4 is an explanatory diagram showing a configuration on the connector side.

In FIG. 6, the AC adapter 3 has a plug 5
Is connected to an outlet of a commercial power supply (not shown), a commercial power supply voltage is supplied, and the commercial power supply voltage is converted to a DC voltage of 7.2 V, for example. The DC voltage generated by the AC adapter 3 is
0 to the plug 31.

At the tip of the plug 31, a cylindrical contact portion 32 is formed. The contact part 32 has, for example, a positive contact part 34 formed on the inner peripheral side and a negative contact part 35 formed on the outer peripheral side, and generates a DC voltage from the AC adapter 3 between the contact parts 34, 35. It has become.

On the other hand, the printer housing is provided with a connector (not shown) into which the contact portion 32 of the plug 31 can be inserted. The connector is formed in a tubular shape, and the negative contact portion 35 is fitted therein. And a positive receiving portion formed in a rod shape inside the cylindrical negative receiving portion and in contact with the positive contact portion 34. These positive and negative receiving parts correspond to the terminals 16 and 15 in FIG. 1, respectively.

In the present embodiment, a notch 33 is formed in a groove shape on the outer periphery of the contact portion 32 of the plug 31. On the other hand, as shown in FIG. 7, an L-shaped locking portion 4 pivotally supported on a shaft 41 is provided in the printer housing.
2 are provided. The locking portion 42 is disposed near the tip of the plug 31 whose one end is inserted into the connector. This one end is formed in a shape that fits into the notch 33 of the plug 31 and is urged by a spring 43 in a direction away from the plug 31.

The other end of the locking portion 42 is disposed near a cam 45 that swings about a shaft 44. The cam 45 swings in conjunction with a head cam (not shown) for moving a thermal head (not shown). The thermal head is moved to different positions during printing and at times other than printing, and the head cam linked to the cam 45 is driven by a motor (not shown) according to the operation mode,
The thermal head is moved by pressing a thermal head arm (not shown) with the cam surface.

The cam 45 operates at a time other than during printing, as shown in FIG.
And the state shown in FIG. 7B at the time of printing. In a state where the plug 31 is inserted into a connector (not shown), when the cam 45 is in the state shown in FIG. 7B, the other end of the locking portion 42 is pushed by the cam surface of the cam 45, One end of the locking portion 42 rotates so as to fit into the notch 33 of the plug 31. Then, the plug 31 is fixed in the insertion / removal direction by the locking portion 42 so that the plug 31 cannot be removed from the connector (not shown).

Further, when the cam 45 is in the state shown in FIG. 7B while the plug 31 is not inserted into the connector (not shown), the other end of the locking portion 42 is connected to the cam 45.
, And one end of the locking portion 42 is
When the connector is mounted, a part of the approach path is closed. Then, the plug 31 cannot be completely inserted into the connector (not shown).

That is, in the present embodiment, the plug 3
1 cannot be inserted into the connector during printing, and the plug 31 cannot be removed from the connector during printing.

The power supply voltage from the AC adapter 3 is
The power supply voltage is supplied to the power supply control unit 27 in preference to the power supply voltage from the power supply unit (see FIG. 1). The power supply control unit 27 supplies the input power supply voltage to the heating element of the thermal head as it is in the first embodiment. The same is true.

In the embodiment configured as described above, the locking portion 42 is rotated by the cam 45 at the start of printing. When the plug 31 is inserted before printing, the locking portion 42 is fitted into the notch 33 of the plug 31. When the plug 31 is not inserted before printing,
The locking portion 42 blocks a part of the approach path of the plug 31.

Thus, after the start of printing, insertion / removal of the plug 31 is prohibited. Therefore, when the plug 31 is inserted before the start of printing, the printing operation is performed by the power supply voltage from the AC adapter 3, and when the plug 31 is not inserted before the start of printing, the battery 21 is inserted. The printing operation is performed by the power supply voltage from the printer. Since only the voltage from the AC adapter 3 or only the voltage from the battery 21 is used from the start to the end of printing, it is possible to prevent the print density from significantly changing and the print quality from deteriorating.

FIG. 8 relates to a fourth embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a configuration on a connector side. The second shown in FIG.
In the embodiment, not only the plug 31 can be pulled out during printing but also cannot be inserted. However, considering continuous printing, etc., the plug 31 may be used even during printing.
It is also conceivable that it is better to make it insertable. The present embodiment is applied to this case.

In this embodiment, the configuration on the AC adapter side is the same as that in FIG. As shown in FIG. 8, a locking portion 52 pivotally supported on a shaft 51 is provided in the printer housing. The locking portion 52 is disposed near the tip of the plug 31 having one end inserted into the connector. This one end is formed in a shape that fits into the notch 33 of the plug 31 and is urged by a spring 53 in a direction away from the plug 31.

Also, the engaging portion 42 has a plunger 54
Is attached, and by pulling the plunger 54 against the urging force of the spring 53, one end of the locking portion 52 can be fitted into the notch 33 of the plug 31. In this state, the plunger 54
Can be locked to a locking portion (not shown).

The plunger 54 locked by the locking portion (not shown) is returned to its original position, so that one end of the locking portion 52 comes off the notch 33 of the plug 31.

Another configuration of the present embodiment is similar to that of the first embodiment shown in FIG.
This is substantially the same as the embodiment.

Next, the operation of the embodiment configured as described above will be described with reference to the flowchart of FIG.

The operation shown in FIG. 9 is different from the operation shown in FIG. 5 only in that steps S31 and S32 are added. That is, if the AC adapter 3 is connected at the time of starting printing, the process proceeds from step S6 to step S31.
Then, the connection of the AC adapter is locked. That is,
Prior to the start of printing, the plunger 54 shown in FIG. 8 is pulled and locked to a locking portion (not shown), and the locking portion 52 is fitted into the notch 33 of the plug 31. This prevents the plug 31 of the AC adapter 3 from being disconnected from the connector of the printer housing.

Next, when the printing operation of one sheet is completed by the processing from step S9 to step S12, step S12 is executed.
At 32, the connection lock of the AC adapter is released.
That is, the locking of the plunger 54 is released, and the locking portion 52 is released.
Is the notch 3 of the plug 31 by the urging force of the spring 53.
Removed from 3. This allows the plug 31 to be freely inserted into and removed from the connector.

The other operations are the same as in the second embodiment.

As described above, in this embodiment, the AC adapter can be inserted and removed every time one sheet is printed, even during continuous printing. Even in this case, since the power supply is not switched until printing of one sheet is completed, it is possible to prevent the print density from significantly changing and the print quality from deteriorating.

[Supplementary Notes] Battery power supply means, AC adapter means for supplying power having substantially the same voltage as the voltage of the battery power supply means, thermal head for printing an image based on image data on paper, power supply from the battery power supply means and AC And a power supply switching means for selectively switching power supply input from an adapter means by a relay and applying the power supply to the thermal head.

2. After the power supply switching means is switched to apply the power supplied from the battery power supply means to the thermal head and the printing operation with the thermal head is started, the AC adapter means is turned on during the printing operation of one sheet. The printer device according to claim 1, further comprising control means for prohibiting the switching of the power input by the power switching means until the printing operation is completed even if the printer is connected.

3. The printer apparatus according to claim 2, wherein the prohibition of switching of the power supply input by the power supply switching means by the control means is released when the printing operation of the one sheet is completed.

4. After the power supply switching means is switched to apply the power supplied from the battery power supply means to the thermal head and the printing operation with the thermal head is started, the AC adapter means is turned on during the printing operation of one sheet. 2. The printer device according to claim 1, further comprising a control unit that controls the power supply switching unit so as to switch the power input from the battery power supply unit to the AC adapter unit after the printing operation is completed when the connection is made. .

5. The printer device according to any one of additional items 1 to 4, wherein the voltage value measurement of the input power supply is performed at least immediately after the print start instruction is input and immediately before the start of the printing operation.

6. The measurement of the voltage value of the input power source is performed only immediately after the input of the print start instruction and immediately before the start of the printing operation, until the print start instruction is input and the printing of one sheet is completed. 6. The printer device according to any one of additional items 1 to 5, wherein

7. The control means determines whether or not the remaining battery charge is sufficient for performing a printing operation based on the measurement result of the voltage value of the input power supply, and based on the measurement result of the voltage value to the heating element in the thermal head. Any one of additional items 1 to 6, wherein the energization time is controlled;
7. The printer device according to claim 1.

[0101]

As described above, according to the present invention, the use of the relay for switching the power supply input has the effect of extending the life of the battery.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a printer device according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the appearance of the device and an AC adapter.

FIG. 3 is an explanatory diagram showing the external appearance of the device and an AC adapter.

FIG. 4 is a flowchart for explaining the operation of the first embodiment.

FIG. 5 is a flowchart showing an operation flow employed in the second embodiment of the present invention.

FIG. 6 is a perspective view showing a configuration on an AC adapter side according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a configuration on a connector side according to a third embodiment of the present invention.

FIG. 8 is an explanatory view showing a configuration on a connector side according to a fourth embodiment of the present invention.

FIG. 9 is a flowchart for explaining the operation of the fourth embodiment.

[Explanation of symbols]

2 ... connector, 3 ... AC adapter, 17 ... battery section, 2
0 relay, 21 battery, 23 control circuit, 24 reference voltage generation circuit, 25 input voltage determination circuit, 26 permission /
Prohibition circuit, 27: power supply control unit.

Claims (4)

[Claims] 1. A thermal head for printing an image based on image data on a sheet of paper, a power supply from a battery power supply, and a power supply from an AC adapter for supplying power having substantially the same voltage as the voltage of the battery power supply A power supply switching means for selectively switching input and output by a relay and applying the input to the thermal head. 2. After the printing operation with the thermal head is started by switching the power supply switching means so as to apply the power supplied from the battery power supply means to the thermal head, and during the printing operation of this one sheet, 2. The printer device according to claim 1, further comprising control means for prohibiting switching of power input by said power switching means until the printing operation is completed even when said AC adapter means is connected. 3. The printer apparatus according to claim 2, wherein the prohibition of the switching of the power input by the power switching means by the control means is released when the printing operation of the one sheet is completed. . 4. After the printing operation with the thermal head is started by switching the power supply switching means so as to apply the power supplied from the battery power supply means to the thermal head, and during the printing operation of this one sheet, 2. The control device according to claim 1, further comprising a control unit that controls the power supply switching unit to switch a power input from the battery power supply unit to the AC adapter unit after the printing operation is completed when the AC adapter unit is connected. The printer device according to 1.