JPH0452226B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a printing device that uses a battery as a driving power source, and in particular to a battery-powered printing device that is equipped with a notification means for notifying the user that the battery voltage has fallen below a certain level. . Prior Art In battery-powered printing devices such as typewriters that use batteries as a driving power source, if the battery voltage drops below a certain level, the printing device may malfunction, so it is necessary to notify the user of this. be. This also applies to recording electronic devices such as electronic desktop calculators with printers, and therefore, Japanese Patent Application Laid-Open No. 10824/1983 describes the following for recording electronic devices:
It has been proposed to provide means for detecting when the power battery has fallen to a level that would cause malfunction of a recording device such as a printer, and notifying the user of this fact. In other words, it has been proposed that when the power supply voltage drops below a certain level, a notification sound is emitted for a certain period of time every time a key is input, but if the battery voltage If an operation that requires a large amount of power is performed continuously, and even if it temporarily drops below a certain level, the operation that does not require that much power will continue, or the electronic device will be in a hibernation state. The battery will recover if it is kept under normal conditions, and it is not necessarily necessary to replace the battery just because the battery voltage once drops below a certain level. Therefore, if the battery is continued to be used as it is, an alarm will be emitted every time the power supply battery temporarily drops below a certain level. This is troublesome, and also has the disadvantage that if a decrease in battery power is reported or not, the user may be concerned that the device has malfunctioned. This situation is the same even when a drop in power supply voltage is notified by a visually appealing display means such as a liquid crystal display. OBJECT OF THE INVENTION The present invention has been made against the background of the above-mentioned circumstances, and therefore, an object of the present invention is to reduce the risk of malfunction of the print head due to the voltage of the power supply battery in a battery-driven printing device. A battery-powered printing device that can notify the user that the battery voltage has decreased to a certain level, and that does not generate disturbing notification sounds or display when the battery voltage has only temporarily decreased below a certain level. Our goal is to provide the following. Structure of the Invention In order to achieve the above-mentioned object, the present invention has a battery-driven printing system that includes a printing head that is driven by a battery to perform printing, and a notification means for notifying a voltage drop of the battery, as shown in FIG. The apparatus includes: (a) a detection circuit for detecting that the battery voltage has fallen below a certain level; and (b) a predetermined movement of the print head while an output signal is being emitted from the detection circuit. The present invention is characterized by comprising a counter that counts the number of operations, and (c) a control means that activates the notification means when the count value of the counter reaches a predetermined value. Note that the predetermined moving operation of the print head herein means an operation that involves movement of the print head, such as a single character printing operation or a line feed operation. If the print head is a thermal head, etc.
In the case of a type that prints by dots, the print head must be moved several steps to print one character, but in this case, one step is defined as one movement of the print head in advance. It is also possible to set it in advance. In a battery-driven printing device, the battery voltage drops to some extent while the print head is moving, but if the battery voltage in this reduced state reaches a certain level or less, a counter is incremented. When the count value of the counter reaches a predetermined value, a notification means for notifying a decrease in battery voltage is activated. Even if the battery voltage once drops below a certain level,
If the battery voltage does not drop below a certain level even after the print head recovers and performs a predetermined movement operation, the counter can be prevented from operating at all. Further, in such a case, it is also possible to actively count down. Effects of the Invention In the battery-driven printing device configured as described above, the notification means does not notify a decrease in battery voltage only if the battery voltage temporarily reaches a certain level or below, and the A decrease in battery voltage is notified only when the battery voltage drops below a certain level during the print head movement operation. Therefore, the user can perform printing operations without being bothered by the effect of the notification means due to a temporary drop in battery voltage, and will definitely know if the battery voltage has truly dropped. It is possible. Embodiments Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIGS. 2 and 3 show external views of a battery-powered portable typewriter that is an embodiment of the present invention.
As is clear from FIG. 1, the typewriter of this embodiment is equipped with a keyboard 10 at the front, and this keyboard 10 includes an alphanumeric key 12, a numeric key 14, a space bar 16, a line feed key 18, and other functions. In addition to various keys that are included in a typical typewriter, arithmetic keys 20 corresponding to addition/subtraction/multiplication/division symbols and equal symbols are arranged.
The keyboard 10 also has a liquid crystal display 22.
A voltage drop display mark 24 is provided in the lower right corner of the display section to notify a voltage drop. It is being
This voltage drop display mark 24 does not appear on the liquid crystal display 22 when the battery voltage is sufficiently high, but appears when the battery voltage truly drops below a certain level, as will be described in detail later. In addition to these, the keyboard 10 also has a line pitch selection switch 26, a first mode selection switch 28, and a second mode selection switch 3 in the upper left corner.
0 is set. The line pitch selection switch 26 is a switch for selecting the print line pitch, and the first mode selection switch 28 is a switch for selecting the operating mode of the typewriter, which is non-print mode, collection print mode, or direct print mode. It is possible to choose one. Here, the non-print mode is a mode in which key-input characters and symbols and calculation results are displayed on the liquid crystal display 22 without printing, and the collection print mode is a mode in which key-input characters and symbols are displayed on the liquid crystal display 22. This is a mode in which the characters and symbols entered by key are displayed on the LCD display 22, and the characters/symbols entered by key are displayed on the LCD display 22, and the characters/symbols entered by the key are displayed on the LCD display 22. This is a mode that prints at the same time. The second mode selection switch 30 is a switch for selecting either a typewriter mode in which the typewriter operates as a normal typewriter or a terminal mode in which it connects to an external device and operates as a data terminal. Although the above components are arranged on the top surface of the keyboard 10, a brightness setting dial 32 for setting the brightness of the liquid crystal display 22 and a power switch 34 are further arranged on the right side surface of the keyboard 10. A printing section 36 is provided at the rear portion of the keyboard 10 as described above. The printing section 36 is normally covered with a cover 38 as shown in FIG. 2, but when in use, the cover 38 is opened as shown in FIG. 3.
A platen 40 is provided below the cover 38, and a carriage 42 is disposed so as to be movable along the length of the platen 40. The carriage 42 has a thermal head 44 as a printing head.
supported, guided by the guide rod 46, moved along the longitudinal direction of the platen 40 by a drive device (not shown), and rotated around the guide rod 46 by another drive device (not shown); The thermal head 44 is attached to the platen 4.
It is configured so as to be pressed against the thermal paper 48 supported by the paper. Note that 50 is a release lever for moving a pair of paper feed rollers (not shown) disposed below the platen 40 for sandwiching and feeding the thermal paper 48 to a non-operating position where they are separated from each other. It is provided. The typewriter having the above structure is controlled by a control circuit as shown in FIG.
In the figure, 60 is a central processing unit (hereinafter abbreviated as CPU), which includes the keyboard 10, a read-on memory 62 (hereinafter abbreviated as ROM), and a random access memory 64 (hereinafter abbreviated as ROM).
(abbreviated as RAM), a printing mechanism driver interface 66, a display controller 68, an external interface driver receiver 70, and the like are connected. A printing mechanism 72 is connected to the printing mechanism driver interface 66, and the liquid crystal display 22 is connected to the display controller 68. Further, an external interface 74 is connected to the external interface driver receiver 70 so that data can be exchanged between the present typewriter and an external device such as a typewriter of the same type or a personal computer. The printing mechanism 72 includes the platen 40 and the carriage 42, a drive device for driving them, and a thermal head 44. In addition, the display controller 68 has a built-in display buffer memory with the same number of digits as the liquid crystal display 22, and the CPU 60 inputs characters and symbols such as alphanumeric characters, numbers, spaces, arithmetic symbols, and other symbols input from the keyboard 10, as well as line breaks. The code data corresponding to each printing function such as printing function, paper feeding function, etc. is sequentially stored in the display buffer memory, and pattern data corresponding to the code data is read from the ROM 62 and supplied to the display controller 68. Also,
The RAM 64 includes a print buffer memory for a certain number of characters, and the print mechanism driver interface 66 controls the print mechanism 7 according to the pattern data read from the ROM 62 by the CPU 60 based on the code data stored in the print buffer memory.
In addition to driving the second thermal head 44, it also controls the motors and the like for driving the carriage 42 and platen 40. Further, the ROM 62 stores a program for controlling the operation of the entire typewriter. The RAM 64 is provided with a text memory 75, which can store a certain amount of character/symbol data and function data including print control data. The RAM 64 further includes a counter register 76, which will be described in detail later along with its operation, and a flag register 78 that stores a weak/battery flag.
is provided. The counter register 76 is 1
Consists of bytes. The typewriter configured as described above can operate in a direct print mode for normal printing operations as described above, as well as a non-print mode and a collection print mode.
Further, by operating the numerical keys 14 and the calculation keys 20, calculations can be performed and the calculation formula and calculation results can be printed on the thermal paper 48, but the operation itself at this time is according to the present invention. Since it is not directly related to understanding, the explanation will be omitted, and only the operation related to the display of the decrease in battery voltage will be explained based on the flowchart of FIG. When the power switch 34 is turned on, the ROM
Execution of the program stored in 62 is started, and initial settings are performed in step S1.
That is, the thermal head 44 is once returned to its original position and then moved to the left margin position to initialize the mechanical parts, and various buffer memories, work memories, etc. are cleared.At the same time, Counter register 76, flag register 78, etc. are also reset. When the initial settings are completed, scanning is performed in steps S2 and S3 to see if any key input has been made, and if any key input has been made, the key input data is displayed on the liquid crystal display 22 in step S4. will be displayed. Then step
In S5, it is determined whether the weak battery flag is ON or not, but since this flag is OFF in the initial stage, the determination result is NO, and the program execution proceeds to step S6. and the battery voltage drop display is displayed.
It is turned off. That is, the voltage drop display mark 2 provided on the liquid crystal display 22
4 is said to be invisible. Next, step S7 is executed and the carriage 4 is
2 is moved one step at a time along the longitudinal direction of the platen 40, a predetermined heating element of the thermal head 44 is made to generate heat, and one character is printed. In other words, if the thermal head 44 prints one character in five steps, printing for one character is completed when the thermal head 44 is moved five steps by the carriage 42. Immediately after the printing of one character is completed, step S8 is executed, and it is determined whether the weak battery switch is in the ON state. Movement of the carriage 42 and thermal head 44
Although the battery voltage drops to a certain extent when the drive is performed, the battery voltage remains almost at this level even immediately after printing one character, so printing for one character is completed. Even if the battery voltage is checked immediately after, the same result as checking the battery voltage is obtained during a printing operation that involves movement of the thermal head 44, and moreover, the CPU 60 is not allowed to control the printing mechanism driver interface 66, etc. This has the advantage that it is not necessary to have the process execute step S8. It should be noted that the weak battery switch can be constructed of, for example, a transistor. A voltage corresponding to the battery voltage is applied to the base of the transistor, and when this voltage drops below a certain level, the transistor becomes conductive and the weak battery switch is turned on. If the judgment result of switch S8 is NO, the program execution moves to step S9, where it is judged whether or not the counter can count down, that is, even if the contents of the counter register 76 are decremented by [1].

A determination is made as to whether or not the value becomes smaller than [0]. If the contents of the counter register 76 are [1] or more, the determination result is YES and the countdown in step S10 is executed, but at this stage the counter register 76 has been reset in the initial setting of step S1. state, its contents, i.e. the count value of the counter, are

Since it is [0], step S10 is not executed, and the program execution moves to step S11. In step S11, it is determined whether the count value is greater than a certain value. In this embodiment, as described above, the counter register 7
6 consists of 1 byte, and in step S11 it is determined whether the most significant digit becomes 1, so in this case, the constant value is [127]. . Since the judgment result is NO at this stage, step S12 is executed, but the weak battery flag is set to step S1.
Since it is already in the OFF state in the initial setting, the program execution returns to step S2 with the state kept as it is. Thereafter, each time a key input is performed, the same operation is repeated and printing is performed, but the battery voltage decreases accordingly, and the result of the determination at step S8 may eventually become YES. In this case, step S13 is executed and it is determined whether or not the counter register 76 can be counted up.However, when the weak battery switch is turned ON for the first time, the count value of the counter is

Since it is [0] and it is possible to count up, the judgment result is YES and the process goes to step S14.
A count-up is performed at . Next, step S11 is executed, but since the determination result is still NO, the program execution returns to step S2 via step S12. If the determination result in step S8 immediately after the printing operation based on the subsequent key input is YES again, steps S13 and S14 are executed, but if the weak battery switch is turned off immediately after the previous printing operation,
Just because it is ON does not necessarily mean that it will be ON immediately after the next printing operation.
If it is OFF, the judgment result in step S8 is NO.
Therefore, steps S9 and S10 are executed, and the contents of the counter register 76 are decremented by [1]. As described above, each time one character is printed or one character's space is moved, it is checked whether the weak button switch is ON or OFF, and if it is ON, the counter register is The contents of 76 are increased by [1] and turned OFF.
If it is in the state, it will be reduced by [1]. Therefore, the weak button switch is activated every time a printing operation is performed.
If the ON state continues, the contents of the counter register 76 will eventually reach [128], so
The result of the determination in step S11 is YES,
Step S15 is executed and the weak battery flag is turned ON. That is, flag register 7
The content of 8 is set to [1]. That is, when the next key input is performed, the determination result in step S5 becomes YES, and the battery voltage drop display is turned on in step S16. That is, the voltage drop display mark 24 provided on the liquid crystal display 22 is displayed. The fact that this voltage drop display mark 24 is displayed means that the weak battery switch was in the ON state during the printing operation for at least 128 characters (actually, since a countdown is also performed, it is equivalent to 128 characters). This means that the weak button switch was in the ON state when printing many characters).
Since the battery voltage has dropped to a level where there is a real possibility that erroneous printing may occur, it is necessary to replace the battery. However, even in this state, it is possible to use the typewriter in a non-print mode that does not involve printing operations. Note that even after the battery voltage drop display is displayed, if the typewriter is used without replacing the battery, the counter register 76
After the content value reaches the maximum value [255], if the count-up is performed further, the content value of the counter register 76 will be reset again.

Since the voltage returns to [0] and the voltage drop display mark 24 disappears, in this case, the determination result in step S13 is NO.
Then, the count-up in step S14 is performed. In the embodiment described in detail above, the battery voltage drop display is not performed while the count value of the counter is below a certain value, but is displayed when it exceeds the certain value. Therefore, in this case, if the battery voltage recovers to a certain level or higher after the count value once exceeds a certain value, the voltage drop display mark 24 will appear or disappear. This kind of thing will not occur if the count value for displaying the voltage drop is set high enough, but in order to more reliably prevent this kind of situation from occurring, follow the flow shown in Figure 6. A program represented by a chart may be stored in the ROM 62. The flowchart in FIG. 6 is similar to the flowchart shown in FIG. 5 up to the countdown in step S10 and the countup in step S14, but the subsequent steps are different.
That is, in step S17, it is determined whether the count value is less than or equal to the first reference value [n],
If the result of the determination is YES, the weak battery flag is turned OFF in step S18, and
In step S19, it is determined whether the count value is equal to the second reference value [N], and if the result of the determination is YES, the weak battery flag is turned ON in step S20. . In addition, step S17 and step
If the result of the determination in S19 is NO, the execution of the program returns to step S2. As shown in FIG. 7, the first reference value [n] is made smaller than the second reference value [N] by a certain value. For example, the second reference value [N] is set to [128], and the first reference value [n] is set to [64]. Therefore, when the count value reaches the second reference value [N]
The weak battery flag that is set to ON will be activated if the count value does not fall to the first reference value [n].
Since the weak battery flag is not set to OFF and the weak battery flag is set to ON, step S16 is executed.
Once the battery voltage drop display is displayed, the display will not be erased even if the battery voltage fluctuates slightly, and a stable battery voltage drop display will be performed. Although two embodiments of the present invention have been described above, these are literally illustrative, and the present invention can be implemented in other embodiments. For example, the means for notifying the battery voltage drop is not limited to using a part of the liquid crystal display 22 as in each of the above embodiments, but it is also possible to provide a separate voltage drop indicator lamp. Also,
The notification means is not necessarily limited to one that appeals to the sense of sight, but it is also possible to emit a notification sound to appeal to the sense of sight. Further, the specific program for notifying the voltage drop is not limited to that of the embodiment described above, and furthermore, the mechanism and control device of the typewriter are also limited to those of the embodiment described above. Rather, the present invention can be implemented with various modifications and improvements based on the knowledge of those skilled in the art.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention. FIG. 2 is an external perspective view of a battery-powered portable typewriter according to an embodiment of the present invention, and FIG. 3 is a perspective view partially showing the state in which the typewriter is used. FIG. 4 is a block diagram showing a control device for the typewriter. FIG. 5 is a flowchart showing a program stored in the ROM of FIG. FIG. 6 is a diagram partially showing a flowchart of a program in another embodiment of the present invention.
FIG. 7 is an explanatory diagram showing ON/OFF control of the weak battery flag according to the flowchart of FIG. 6. 10: Keyboard, 22: Liquid crystal display,
24: Voltage drop display mark, 36: Printed part, 4
2: Carriage, 44: Thermal head, 60:
Central processing unit (CPU), 62: Read only memory (ROM), 64: Random access memory (RAM), 68: Display controller, 7
6: Counter register, 78: Flag register.

Claims (1)

[Scope of Claims] 1. In a battery-driven printing device having a print head that is driven by a battery to perform printing and a notification means for notifying a voltage drop of the battery, detecting that the battery voltage has fallen below a certain level. a counter that counts the number of predetermined movement operations performed by the print head while the output signal is being emitted from the detection circuit; and when the count value of the counter reaches a predetermined value. A battery-driven printing device characterized by comprising: a control means for activating the notification means.