JPH03159776A - Printer - Google Patents

Abstract

PURPOSE:To enable lengthening the working life of a printer usable through a battery with a constant capacity by lowering the driving supply voltage of the printer and by lengthening an exciting pulse width, when a battery voltage falls below a preset voltage at the time of printing through the printer. CONSTITUTION:A printer-driving power circuit 3 is controlled by a printer power supply control signal 7 from a control circuit 2 so that a printer power supply voltage 8 is set to a certain voltage V0[v], and the exciting pulse width t0[sec] of a printer unit 4 is set by an exciting pulse signal 9 from the control circuit 2. In this case, when a power supply voltage 5 drops at the time of excitation and the detection circuit of a power circuit and battery voltage detection circuit 1 detects that the power supply voltage falls below a set voltage, a voltage detection signal 6 indicating to that effect is inputted to the control circuit 2. The control circuit 2 receiving the signal 6 sets the printer power supply voltage 8 to Vo- V(v) by the printer power supply control signal 7 and the exciting pulse width to t0+ t[sec] by the exciting pulse signal 9.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a printer using a battery as a power source.

[Prior Art J] For example, there is a word processor with a printer as an electronic device that uses a battery as a main power source and operates a printer using the main power source.

Conventionally, in electronic devices such as those mentioned above, when the battery voltage becomes lower than a preset voltage (Low Ba
(When low battery occurs), either the power is automatically turned off, or the application is notified of the occurrence of Low Battery and instructed to terminate the application immediately, or if this occurs during printer printing, the printer is stopped and the printer is turned off. It is structured so that it cannot be used.

[Problem to be Solved by the Invention 1] In the conventional example described above, a large amount of energy is required for each moment when printing, and as a result, a large current flows instantly from the battery, causing a temporary drop in the battery voltage. .

In this situation, even though there is still some remaining battery capacity, the voltage has temporarily dropped due to the energy required for printer printing, and if the printer does not print, there will still be enough battery capacity left. In addition, if the instantaneous energy for printer printing is reduced, the printer can also print. However, in the above conventional example, even in such a case, if the voltage becomes lower than the preset voltage, it is treated as a normal Low Battery.
There was a drawback that the printer could no longer be used by notifying the printer. An object of the present invention is to provide a printer that solves the above problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a printer unit, a battery, a printer drive power supply circuit that uses the battery as a power source to generate a printer drive voltage, and a detector that detects the battery voltage. and fltlJ control means for controlling the printer drive voltage and the excitation pulse width of the printer unit in response to the voltage drop detected by the detection means.

[Function] According to the present invention, when the battery voltage drops during operation of a battery-operated printer, the voltage drop that occurs instantaneously due to, for example, the printer printing voltage being lowered and the pulse interval lengthened can be suppressed to a small level, and the battery voltage can be reduced. The lifespan of will be extended.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an embodiment, 1 is a power supply (battery) circuit and a battery voltage detection circuit that detects a preset voltage, 2 is a control circuit that controls the printer voltage and excitation pulse width, and 3 is a control circuit that controls the printer voltage and excitation pulse width. 4 is a printer driving power supply circuit (usually using a booster circuit), and 4 is a printer unit.

In normal operation, the printer drive power supply circuit 3 is controlled by the printer power supply control signal 7 from the control circuit 2, and the printer power supply voltage 8 is set to a certain voltage V. [v]
The excitation pulse width t, [secl] of the printer unit 4 is set by the excitation pulse signal 9 from the control circuit 2. The resistance of printer unit 4 is r [Ω] (constant)
Then, the energy consumed by printer unit 4 W0
is yO2W. It is expressed as =-t0 r. When the power supply voltage 5 drops during excitation and the detection circuit of the power supply circuit and battery voltage detection circuit 1 detects that it is below the set voltage, a voltage detection signal 6 indicating this is input to the control circuit 2. Upon receiving this signal, the control circuit 2 uses the printer power control signal 7 to set the printer power supply voltage 8 to v0-ΔV[vl, and uses the excitation pulse signal 9 to set the excitation pulse width to 1. +Δt [sec]. At this time, two (vo-Δ"'(t.+at)=i.

By setting r, the printing speed becomes slower, but since the energy is the same as before the voltage drop, it is possible to reduce the voltage drop without degrading the printing quality. The reason why the voltage drop becomes smaller is as follows. That is, since the battery has internal resistance, the voltage drop increases as the current flowing out of the battery increases. in this case,
Assuming that the efficiency of the printer drive power supply circuit 3 is 100%, normally i. = 艷r After voltage detection, i. =Vo-AV r and obviously i<io. When the circuit 3 boosts the voltage and the efficiency decreases, it becomes more advantageous because the voltage is v0=Δv<Vo (generally, the smaller the boost width is, the higher the efficiency is), and the current i decreases.

Figure 2 shows the power supply waveform when this is implemented, together with the conventional example (Q). FIG. 2 [F] is the conventional method, and B
A voltage drop occurs every time the printer is excited, and at point A? B 3a
ttery has been detected and the operation has stopped. In Figure 2, ■■■, the detection at point A is the same, but by controlling the constant voltage and pulse width as described above, the voltage drop becomes smaller as shown in C, making it possible to continue printing. It becomes possible.

To give a specific example, when the same printer was continuously driven using a 6V (capacity 700+nA) battery, the conventional printer could continuously use 4,000 lines, and the present invention could continuously use 4,500 lines.

Note that the voltage detection signal 6 is not a preset voltage but a signal obtained by constantly reading the battery voltage, and the control circuit 2 adjusts the printer power supply voltage V. While constantly controlling the excitation pulse width t and maintaining ΔV. It is also possible to change Δt to maximize the printing speed to the full capacity of the battery depending on the battery voltage.

[Effects of the Invention] As explained above, according to the present invention, when the battery voltage falls below a preset voltage during printer printing,
By lowering the printer's drive power supply voltage and extending the excitation pulse width, it is possible to increase the usage time of the printer with a fixed capacity battery.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, (α) Fig. 2 [present] is a diagram showing the battery voltage waveform when using a conventional printer, (bl Fig. 2 [F] is a diagram when using a printer according to the present invention) 1 is a diagram showing battery voltage waveforms. 1... Power supply circuit and battery voltage detection circuit, 2... Control circuit, 3... Printer driving power supply circuit, 4... Printer unit. 3. 4

Claims (1)

[Claims] a printer unit, a battery, a printer driving power supply circuit that uses the battery as a power source to generate a voltage for driving the printer, a detection means for detecting the voltage of the battery, and a voltage drop in the voltage detected by the detection means. A printer comprising: control means for controlling a printer driving voltage and an excitation pulse width of the printer unit.