JPH01190471A - handy printer - Google Patents

Abstract

PURPOSE:To enable the display of reduction in the capacity of a battery so as to allow operations other than printing to be performed even if the capacity of the battery is reduced by providing a detector means for detecting the battery voltage, a display means for displaying the results from the detection and a power source circuit for switching off the power supply for the circuit depending on the detection results. CONSTITUTION:A transistor 29 is switched ion when the voltage of a battery becomes higher than V2 with a circuit 31 being in operation, while it is switched on when the voltage of the battery becomes equal to or less than V1 with a printing circuit 32 being in operation, whereby the circuit 31 is put into operation. However, a transistor 26 is put in an off state since the output from a voltage detector 25 becomes 'L' with the output from a NAND gate 27 becoming 'H', whereby the printing circuit section becomes out of operation. At this moment, the detection results of a voltage detector 25 is supplied to the circuit 31, and an indication displayed on a liquid crystal panel is caused to flash, whereby the user is informed that a printing operation is not possible. In addition, in a case where the circuit 31 and the printing circuit 32 are both in operation, when the voltage of the battery is equal to or less than V1 and V2, the transistors 26, 29 are both switched off, whereby the operations of the circuit 31 and the printing circuit 30 are made impossible.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a power supply circuit for a handy printer.

[Conventional technology]

It is known that in conventional handy printers, when the battery voltage drops due to a printing operation, the power to the circuit is turned off, and the operation of other circuits is also prohibited thereafter.

[Problem to be solved by the invention]

However, with the above-mentioned conventional technology, the battery must be replaced while sufficient battery capacity remains to operate the circuit section except the printed circuit section. Because the person knows this, he or she cannot perform operations such as saving data to an external storage device in advance.

Therefore, the present invention aims to solve these problems.
The purpose of this is to display the state of decrease in battery capacity and to enable operations other than printing operations even in the state of decrease in battery capacity.

[Means to solve the problem]

The handy printer of the present invention includes: a) a detection means for detecting battery voltage; b) a display means for displaying the detection result; and C) a power supply circuit for turning off the power of the circuit according to the detection result. It is characterized by

〔Example〕

Hereinafter, the present invention will be described in detail based on Examples.

FIG. 1 is a block diagram of a handy printer of the present invention. 1 is an input circuit for inputting print data; 2 is a storage circuit for storing the print data input by the input circuit 1; and 3 is a display control circuit for displaying the print data. The print data stored in the storage section is decoded by the decoder 4. Reference numeral 5 denotes a display driver, which displays print data in a range of 0 or more, which lights up the liquid crystal panel 6 based on the signal from the decoder 4.

7 is a print control circuit for printing the print data, and the print data stored in the storage circuit 2 is decoded by the decoder 4. 8 is a thermal head driver which drives the thermal head 9 using the signal from the decoder 4 to perform printing.

10 is a power supply circuit that supplies power to each of the aforementioned circuits. Further, the battery voltage is detected, and depending on the detection result, the power of the circuit is turned off, or a decrease in the battery capacity is displayed on the liquid crystal panel 6.

FIG. 2 is a circuit diagram of the power supply circuit of the present invention.

21 is a battery, and 22 is a power switch. 25 and 2
Reference numeral 8 denotes a voltage detector using a comparator or the like, and the detected voltage values are V, , and V2, respectively. In addition, the output of the voltage detector is L' when the detected voltage is below Vl (V2),
V, (V,) or more becomes 'H'. 23 is a diode, and 24 is a capacitor, which serves as a backup to protect the circuit other than the printed circuit section (hereinafter referred to as the circuit) from a large drop in battery voltage due to the large pulse-like current flowing through the printed circuit section 30. It is element. 26 is a transistor that switches the power supply of the printed circuit section 30;
2 is a circuit diagram for switching the power supply of the circuit 31;

If the printing circuit 30 and the circuit 31 are in operation and the battery voltage is higher than the detection voltage V, , V2 of the voltage detector, both transistors 26 and 29 are turned on, so the printing circuit and the circuit are normal. Operate.

Next, when the battery voltage is 72 or more when the circuit 31 is in operation, and less than 72 when the printing circuit 30 is in operation, the transistor 29 is turned on and the circuit 31 is put into the operation state. However, transistor 26
The output of the voltage detector 25 becomes "L", and the NAND gate 27 becomes a blank output, so it is turned off and the printing circuit section does not operate.At this time, the circuit 31 inputs the detection result of the voltage detector 25, (not shown in the drawings)) notifies the user that the printing operation is no longer possible by blinking the display displayed above.

Furthermore, when the battery voltage is in the operating state of the circuit 31 and the printing circuit 30, when the voltage detector detection result is less than ■1 or ■2,
Both transistors 26 and 29 are in the off state, and the circuit 31 and printing circuit 30 do not operate. Also, the detection result of the voltage detector 28 is input to the NAND gate 27, and the detection result of the voltage detector 28 is input to the NAND gate 27. Also, the operation of the transistor 26 is prohibited.

It should be noted that the example given here is just one example.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to confirm on the liquid crystal panel whether the battery capacity has decreased and printing is not possible, and therefore the user can be informed when it is time to replace the battery. Another advantage is that even if printing is disabled, printing data can be input, so the battery can be used effectively.

Furthermore, when the circuit is inoperable, the printing circuit is also inoperable, so it is possible to prevent the thermal head from generating heat due to runaway of the printing circuit.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention, and FIG. 2 is a power supply circuit diagram of the present invention. 1... Input unit 2... Storage unit 3... Display control unit 4... Decoder 5... Display driver 6... Liquid crystal panel 7... Print control unit 8... Thermal head Driver 9... Thermal head 10... Power supply circuit' □ Applicant: Seiko Epson Corporation ￥2 Diagram

Claims (1)

[Scope of Claims] Means for electro-optically digitally displaying data input from the outside through a keyboard or the like or data transferred from an external storage device (hereinafter referred to as data); and means for displaying the data using a thermal head. a) a detection means for detecting the battery voltage; b) a display means for displaying the detection result; and c) a display means for displaying the detection result. A handy printer characterized by having a power circuit for turning off the power of the printer.