JPS5845076A - Typewriter - Google Patents

Abstract

PURPOSE:To keep the density of printing constant for a long period of time by controlling the printing pressure by printing pressure data put in ROM in a typewriter capable of properly regulating the printing pressure. CONSTITUTION:In general Japanese character typewriter, when a type bar is driven weakly for letters with less stroke number and also strongly for letters with many stroke number, the density of printing is kept constant. The printing pressure of Japanese character typewriter is controlled by controlling the suction speed of solenoid by a servo. When CPU7 knows what letters to be next printed are, the address of ROM corresponding to the letters is directed and content is read out of the address. The output is analogized by a D/A converter 9 and amplified by an amplifier 10 to become the command width of printing pressure. Thus, safer and smaller printing pressure than in the conventional methods can be commanded without any variation with time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a typewriter in which printing pressure can be appropriately adjusted.

In general, Japanese typewriters have the disadvantage that when the type bar is driven at a certain strength, characters with a small number of strokes are printed darkly, and characters with a large number of strokes are printed thinly, resulting in a significant drop in print quality. Therefore, when printing with a manual Japanese typewriter, it is necessary to adjust the type bar driving force so that the typewriter hits the platen weakly for characters with a small number of strokes, and strongly hits the platen for characters with a large number of strokes. It requires advanced operating skills based on many years of experience to fully utilize it. There is also an electric Japanese typewriter that uses a solenoid to drive the type bar. The printing pressure of this Japanese typewriter is controlled by controlling the suction speed of a solenoid using a servo. FIG. 1 shows its block diagram.

In the figure, 1 is a printing pressure presetting section that presets various voltages using multiple variable resistors, 2 is an analog switch section that selects one of the printing pressure voltages and outputs it as a command value, and 3 is a movable solenoid. A speed detection section detects the moving speed of the iron core and outputs it as a feedback voltage. 4 is a comparison section that compares the above command value and the foot voltage. 5 is a comparison section that controls the suction and This is the drive part that changes speed.

As mentioned above, it is necessary to divide the printing pressure into a large number of stages depending on the number of character strokes, size, type, number of copies, etc., and if you try to achieve this with the conventional method, Several tens to hundreds of variable resistors are required. However, the use of such a large number of variable resistors requires a very large circuit board size, resulting in high costs and is extremely difficult to implement. Even if it were realized, the resistance value of the variable resistor is likely to change over time, and as a result, there is a drawback that the preset voltage that determines the printing pressure changes.

Therefore, in an actual circuit, the number of presets is limited to several tens, and accordingly, the ranking of printing pressures is also limited and rough. However, even in this case, drift of the preset voltage cannot be avoided.

The present invention eliminates the above-mentioned drawbacks of conventional typewriters,
A simple circuit configuration enables precise printing pressure settings, and
The present invention provides a typewriter whose set voltage changes little over time. The present invention will be explained below along with one embodiment thereof. FIG. 2 is a block diagram showing the configuration up to outputting the command value, which is the main part. In the figure, 7 is a central information processing unit (CPU), 8 is a read-only memory (ROM), and this ROM 5 is composed of a byte ROM at 1, which is divided into 8 levels of ranking based on the number of strokes of a character, and 2 levels of character type. , 6 levels of character size, 6 levels of number of copies for a total of 480 types, printing pressure is 8
Written as bit data.

9 is a D/A converter, and 1o is an amplifier.

Next, the operation of this embodiment will be explained. CPU7 is
When the next character to be printed is known, the ROM address corresponding to that character is addressed.

Then, the contents of the addressed address are output from ROMg. This output is converted into an analog by the D/A converter 9 and amplified by the amplifier 10 to become the print pressure command value 7 - According to this Japanese typewriter, if the capacity of the ROM 8 is increased, the printing Since any number of pressure data can be entered, very precise printing pressure can be commanded. Due to the tassels, there is no shading in the print, resulting in good print quality. In addition, just by specifying the address of ROM 5 corresponding to the type to be printed, the printing pressure command value corresponding to that type is output, so unlike the conventional method, there is no need to use a variable resistor for the number of types of printing pressure. There is no need to prepare an analog switch, and there is no need to prepare a variable resistor over time or the instability of an analog switch, making it possible to issue stable command values.

In the above example, we talked about a Japanese typewriter, but
Similar techniques can be applied to other characters (English characters, etc.).

As is clear from the above description, according to the present invention, a read-only memo! Since the printing pressure is controlled using the J(ROM)i, printing can be performed with an appropriate printing pressure corresponding to the printed characters, and printing quality can be improved. Furthermore, the use of ROM allows the structure to be made compact.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional typewriter, and FIG. 2 is a block diagram of a typewriter according to an embodiment of the present invention.

Claims (1)

[Claims] A control means for controlling the rotational speed of the type bar, a read-only memory that stores a command value for the rotational speed as digital data for printing, and a processing means that specifies a read address of the read-only memory and reads the digital data. A typewriter, characterized in that the read digital data is applied to the control means to obtain a printing pressure according to the printed characters.