JP2792086B2 - Printing device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a print hammer for a printing apparatus having a plurality of dot print print hammers.

[Background of the invention]

The configuration of a printing apparatus to which the present invention is applied, the structure of a conventional printing hammer, and the like will be described with reference to FIGS. 3 and 4. FIG.

The hammer bank 1 provided with a large number of print hammers 2 is reciprocated by the shuttle mechanism 30 in the horizontal direction in FIG. Ink ribbon 31 and paper are on the front of hammerbank 1
A platen 36 is disposed via 35. Ink ribbon 31
Is a tape-shaped endless type driven by a pair of ribbon drive rollers 33 and housed in a ribbon cassette. The stored ink ribbon 31 is pulled out from the outlet of the ribbon cassette 34 and used.
The four ribbon guides 32 guide the ink ribbon 31 to travel along a predetermined route, and are arranged so that the ink ribbon 31 crosses the front surface of the hammer bank 1. The paper 35 is fed in a direction perpendicular to the paper of FIG. 3 by a paper feed motor and a paper feed tractor (not shown). Platen 36
Is a sheet that supports the printing force of the printing hammer 2 and
The traveling guide 35 is supported at both ends by bearings 37. Although this apparatus prints characters and figures having a dot configuration, the printing method is widely known in the related art, and therefore the description thereof is omitted.

The structure and operation principle of the printing hammer 2 will be described with reference to FIG. The printing hammer 2 includes a hammer spring 12 for holding printing energy and a printing pin 3 for dot printing attached to a tip of the hammer spring 12. The print pin 3 is attached to the hammer spring 12 by, for example, caulking.
It is manufactured by various methods such as a method in which the tip of the hammer spring 12 is bent to form a print pin at the tip. A member called a plunger 4 for forming a magnetic path is attached to the hammer spring 12 as needed. Illustrated plunger 4
Are attached by a caulking method as in the case of the printing pin 3, but may be attached by another method such as brazing. Of course, the plunger 4 may not be necessary in a print hammer having a configuration capable of forming a sufficient magnetic path. The hammer spring 12 is attached to a hammer base 7 by bolts 6 via a front yoke 5. Further, a comb yoke 9 is attached to the hammer base 7 with a bolt 11 via a magnet 8 to form the configuration shown in the figure.

The hammer spring 12 is normally attracted to the attraction surface 9s of the comb yoke 9 by the magnetic circuit having the above-described configuration, and holds the bending energy serving as printing energy. The coil 10 is used to release the sucked state and perform dot printing.
Is attached to the com yoke 9. When the hammer spring 12 is attracting the comb yoke 9, its attracting surface 12s is inclined at an angle α with respect to the vertical direction in the figure. That is, the suction surface 9s of the comb yoke 9 has a step δ with respect to the hammer spring mounting surface 7s of the hammer base 7 and is inclined at an angle α.

It is very difficult to machine such an inclined surface on the hammer spring mounting surface 7s of the hammer base 7 with high accuracy. The accuracy of the inclined surface needs to be increased as the operating characteristics of the print hammer 2 are increased, that is, as the speed is increased. In order to increase the speed, it is necessary to increase the natural frequency of the hammer spring 12. To achieve this, the ratio k / m of the spring constant k of the hammer spring 12 to its mass m is used.
Must be increased. That is, the spring constant k is increased or the mass m is reduced. This relationship is generally known It is represented by the following equation. On the one hand, the printing energy J is (X is the amount of deflection of the hammer spring 12). In order to maintain a constant impact force when printing, it is necessary to keep this printing energy J constant. The deflection x of the hammer spring 12 is determined by the step δ and the inclined surface α of the suction surface 9a of the comb yoke 9. In order to keep the printing energy J constant while the spring constant k is increased in order to increase the speed of the printing hammer 2, the accuracy of the step δ must be further improved because the dispersion of the deflection x must be smaller than before. It is necessary to make it accurate. The inclination angle α of the suction surface 9s also needs to be improved so as to match the inclination angle of the hammer spring 12.

If the angle is out of order, one-sided contact occurs when the hammer spring 12 is attracted (only the upper or lower part of the attracting surface comes into contact without contact). When the one-sided contact occurs, the deflection amount x of the hammer spring 12 varies, and when the printing operation of the printing hammer 2 is completed, the hammer spring 12 is attracted to the comb yoke and comes to a standstill to be in an initial state. Would. If the next dot printing is performed before the end of the vibration, the operating characteristics of the hammer spring 12 are significantly reduced. This is the adsorption surface 9s
An accuracy error of 10 μm is an unacceptable value due to operating characteristics.
To prevent this, the processing accuracy of the suction surface 9s needs to be on the order of μm. If this cannot be ensured, a dot removal phenomenon occurs due to variations in printing power and inoperability. This greatly reduces the reliability of the printing device.

As described above, as the speed of the printing hammer 2 increases, the processing accuracy of the suction surface 9s of the comb yoke 9 must be improved, but its total length is 13.6 inches (345.44 mm) or more. It is difficult to process a high precision. There is a limit to improving the operation characteristics of the printing hammer 2 as in the present configuration more than the current state, for the reasons described above. Even if the inclined surface is machined with high precision, it cannot be realized at low cost in mass production.

Suction surface of comb yoke 9 with speeding up of printing hammer 2
The accuracy of 9s must be improved more than before, but at the same time, the speed of the printing hammer 2 must be increased. In order to increase the speed of the printing hammer 2, it is necessary to increase the ratio k / m between the spring constant k of the hammer spring 12 and its mass m, as described above. Generally, when the mass m of the hammer spring 12 is reduced, the spring constant k is also reduced, and the value of k / m does not change. However, it is also an important issue to devise this to increase the speed. .

[Object of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned problems that occur with the speeding up of the printing hammer and to improve the performance of this type of printing apparatus.

[Summary of the Invention]

The present invention focuses on the fact that the inclined surface for adsorbing the hammer spring to the comb yoke is provided on the comb yoke, which makes processing of this surface difficult, and the suction surface is attached to the hammer spring mounting surface of the hammer base. And the shape of the hammer spring is devised so as to reduce the weight without lowering the spring constant of the hammer spring.

(Example of the invention)

One embodiment according to the present invention will be described with reference to FIG.

The configuration of this printing apparatus is the same as that of the above-described embodiment except for the parts described below, and the description of those parts will be omitted.

The figure shows a state in which the hammer spring 12 is released from the suction surface 9s of the comb yoke 9 and is neutral. The printing hammer 2 performs dot printing in this state. The suction surface 9s of the comb yoke 9 is parallel to the hammer spring mounting surface 7s of the hammer base 7 as shown in the drawing, and has no step. That is, they are configured to be in the same plane.

The suction surface 12s of the hammer spring 12 is inclined so that the suction surface 9s of the comb yoke, which is in the initial state after the dot printing of the hammer spring 12 is completed, is left without any gap. That is, the inclined surface formed on the suction surface 9s side of the conventional comb yoke 9 is replaced with the suction surface 12 of the hammer spring 12.
This is provided on the s side.

Examples of the dimensions of each part of the printing hammer 2 having the high-speed characteristics at present are shown below. The thickness of the hammer spring 12 is 0.7m
m. The deflection amount x at the print pin 3
It is about 0.35 to 0.4 mm. Further, the ratio of the length from the root of the hammer spring 12 to the printing pin 3 and the length from the root to the suction surface is about 1.5. Therefore, hammer spring 1
The gap between the adsorbing surfaces of the comb yoke 9 and the hammer spring 12 when dot printing is performed on the line 2 is about 0.2 mm. Further, the inclination angle of the suction surface 12s is about 1.5. Because of the dimensions described above, the shape of the inclined surface provided on the hammer spring 12 side is as shown in the figure. From the above, the plate thickness at the tip of the hammer spring 12 is about half of the plate thickness before machining the inclined surface. Processing such an inclined surface can be performed with sufficiently high precision by grinding or the like after attaching the printing pin 3 and the plunger 4 to the hammer spring 12.

This processing is much easier than the processing of the inclined surface provided on the comb yoke 9 side. The figure is a diagram in which the plunger 4 and the print pin 3 are attached by a caulking method.
It may be attached by brazing or other methods. In this case, the inclined surface may be machined before mounting, and this makes the machining easier.

By providing the inclined surface on the side of the hammer spring 12, the thickness m of the hammer spring 12 from the printing pin 3 to the suction surface 12s is reduced, and the mass m is reduced. That is,
Although the weight of the hammer spring 12 can be reduced, the spring constant k does not decrease. This is because the range in which the hammer spring 12 is a spring is from the mounting surface to the lower end of the suction surface 12s, and the plate thickness of the hammer spring 12 is not reduced in that range.

 Another embodiment of the present invention will be described with reference to FIG.

The shape of the hammer spring 12 depends on the configuration method as the printing hammer 2, for example, a type in which the plunger 4 is not attached, the mounting pitch (interval when the printing hammers are arranged in the column direction), and the target operating characteristics (printing force). , Hammery repeatability, etc.). Therefore, the suction surface 9s of the comb yoke 9 may not always be provided on the same plane as the hammer spring mounting surface 7s of the hammer base 7. If the hammer spring 12 is forcibly inserted into the same plane, the tip of the hammer spring 12 after the slope processing is too thin. At this time, the periphery of the mounting surface of the print pin 3 becomes weaker in strength, and the inclined surface provided on the hammer spring 12 penetrates toward the root thereof. The problem of slowing down.

In such a case, as shown in FIG. 2, the suction surface 9s of the comb yoke 9 is provided with a step relative to the hammer spring mounting surface 7s of the hammer base 7. Processing is a little more difficult than in the embodiment shown in FIG. 1 since no inclination is made. However, compared to the conventional processing of a stepped inclined surface, the processing is considerably easier and the processing accuracy is improved.

〔The invention's effect〕

According to the present invention, by providing a slant surface on the hammer spring side for giving a deflection to the hammer spring and securely absorbing it to the comb yoke, the suction surface of the comb yoke is in the same plane as the hammer spring mounting surface of the hammer base. Alternatively, since the surfaces can be parallel, the precision of the suction surface of the comb yoke can be improved, the characteristics of the printing hammer can be improved, and the processing cost of this surface can be reduced. In addition, since the weight of the hammer spring can be reduced without lowering the spring constant, the speed of the printing hammer can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view of a printing hammer showing one embodiment of the printing apparatus of the present invention, FIG. 2 is a sectional view of a printing hammer showing another embodiment of the present invention, and FIG. FIG. 4 is a cross-sectional view of a printing hammer according to the prior art. In the figure, 12 is a hammer spring, 12s is a suction surface of a hammer spring, 9 is a comb yoke, and 9s is a suction surface of a hammer spring of a comb yoke.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B41J 2/245 B41J 2/275-2/28

Claims (3)

(57) [Claims] 1. A hammer spring having a plurality of dot printing print pins, a comb yoke having at least an attraction surface for attracting the hammer spring for applying deflection energy to the hammer spring, and a mounting surface for attaching the hammer spring. A hammer bank having a magnetic circuit provided with a hammer base, reciprocating means for reciprocating the hammer bank in a printing digit direction, paper feeding means for feeding printing paper, and printing pins of the hammer spring. And a platen for supporting the printing of
What is claimed is: 1. A printing apparatus for printing characters, figures, and the like in a dot configuration by a printing pin during reciprocating movement of said hammer bank. A printing device characterized by being provided on a suction surface of a hammer spring. 2. The printing device according to claim 1, wherein the hammer spring suction surface of the comb yoke is provided in the same plane as the hammer spring mounting surface of the hammer base. 3. The printing apparatus according to claim 1, wherein the hammer spring suction surface of the comb yoke is parallel to the hammer spring mounting surface of the hammer base, and a small step is provided.