JPS587381A - Automatic typewriter - Google Patents

Abstract

PURPOSE:To enable a striking force for printing to be finely adjusted in a free manner, by a method wherein a variable-gain amplifier is provided between an output circuit for a preset command value and a comparing part, and the amplification degree of the amplifier is changed. CONSTITUTION:In an automatic typewriter wherein a detection value fed from a detecting part 3 for the moving velocity of a type bar and a command value preset on a presetting part 1 for printing pressure by an analog switch 2 are compared with each other by the comparing part 4 and the velocity of the type bar is controlled to adjust the printing pressure, the variable-gain amplifier 7 is provided between the switch 2 outputting the command value and the comparing part 4, and a target value of the printing pressure is finely adjusted by changing the amplification degree of the amplifier 7. A non-inversion amplifying circuit can be used as the variable-gain amplifier 7, in which case the output value VO of the amplifier 7 can be finely adjusted in a free manner by setting a command value VS by the analog switch 2 and changing the resistance value of a variable resistor Rf.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic typewriter capable of adjusting printing pressure and producing high quality printing.

On a Japanese typewriter, if you drive the type bar with a certain force, the characters printed with a wide printing area will be printed thinly, and the characters that are narrow will be printed darkly, resulting in a There are drawbacks that significantly reduce quality.

Therefore, automatic typewriters require a device that changes the printing impact force of the typewriter bar depending on the font size, font type, and number of copies. Furthermore, since the shading of printing is determined in part by the typist's sense, it is necessary for the typist to be able to freely and finely adjust the printing impact force.

Conventional automatic typewriters employ a method in which a solenoid is used as a drive source for the type bar, and the printing pressure is varied by varying the suction speed of the solenoid. FIG. 1 shows this type of typewriter.

In Fig. 1, 1 is a printing pressure preset section that presets various stain pressures using a plurality of variable resistors, 2 is an analog switch section that selects one of the printing voltages and outputs it as a command value, and 3 is a solenoid. 4 is a speed detection section that detects the moving speed of the movable iron core and outputs it as a feedback voltage, 4 is a comparison section that compares the above command value and the feedback voltage, and 6 is a solenoid 6 according to the comparison result.
This is the drive part that changes the suction speed. Therefore,
The number of variable resistors of the printing pressure presetting section 1 is required as many as the number of types of printing pressure required depending on the number of strokes, size, type, and number of copies of characters. However, their number is inevitably limited due to board size and price. Now, let us assume that six variable resistors are used. Number the variable resistor from Jf61 to A6,
If the relationship between each of these and the preset printing level is modeled, the result will be as shown in FIG. 2. As shown in this figure, the -print level can only be changed in steps, so even if a typist were to print at a print level of 3.6, it would be impossible.

The present invention aims to eliminate such conventional drawbacks, and to enable higher-quality printing by allowing the typist to freely set the level when he/she decides that he or she wants to print at an intermediate level between the stepped printing levels. It is.

This will be explained below along with examples. In Figure 3, 1
2 is a printing pressure preset section, 2 is an analog switch section, 3 is a speed detection section, 4 is a comparison section, 5 is a drive section, and 6 is a solenoid. Those indicated by numerals 1 to 6 correspond to the parts with the same numerals in FIG. Reference numeral 7 denotes an amplifier that amplifies the voltage of the command value selected by the analog switch section 2.

FIG. 4 shows the specific structure of this amplifier, which is composed of general non-inverting amplifier ports and channels.

If v8 is the input voltage and vo is the output voltage, the following equation holds true.

V0=(1+Rf/R,)V.

Now, if R is a fixed resistor, Rf is a variable resistor that can be operated by a typist, ■ is the command value selected by the analog switch 2, and vo is the output of the amplifier 7, then the analog switch 2
Even if the command value selected in is fixed, the typist can
By changing the value of t, the output value of the amplifier 7 can be changed freely.

FIG. 6 shows the change in print level for each preset voltage when the amplifier 7 is changed from 0.6 to 1.5. In FIG. 6, for example, if analog switch 2 selects variable resistance number 4, the print level is 4 in the conventional method.
It was fixed. However, if the value of the variable resistor RfO is changed and the amplifier 7 is varied in the range of 0.5 to 1.5, the print level changes from 2 to 6. The range of change in print level for each variable resistance number is indicated by diagonal lines in the figure.

As is clear from the above description, according to the present invention, by providing an amplifier that allows the typist to change the amplifier in the circuit that determines the moving speed of the type bar, the typist can adjust the printing level. This allows for extremely fine print level settings and improves print quality. In addition, it is possible to maintain good print quality by quickly responding to changes in the set print level over time and special printing conditions.

[Brief explanation of drawings]

Figure 1 is a block diagram of a conventional automatic typewriter, Figure 2 is a block diagram of a conventional automatic typewriter.
The figure shows the printing level, Figure 3 is a block diagram of an automatic typewriter according to an embodiment of the present invention, Figure 4 is a wiring diagram showing the specific configuration of the main parts, and Figure 5 is the same. FIG. 3 is a diagram showing print levels. 1... Print pressure preset section, 2... Analog switch section, 3... Speed detection section, 4
...Comparison section, 5...Drive section. Name of agent: Patent attorney Toshi Nakao
1m Legs 3 Figure 4 Good Figure 5

Claims (1)

[Claims] In an automatic typewriter that compares the detected value of the moving speed of the type bar with a preset command value in a comparator and controls the moving speed of the type bar to adjust the printing pressure, the command value is output. An automatic typewriter, characterized in that a variable gain amplifier is provided between a circuit for detecting a signal and the comparing section, and the target value is finely adjusted by changing the degree of amplification.