JPH0631939A - Impact dot head - Google Patents

Abstract

PURPOSE:To prevent the generation of the breaking of a wire even when an impact dot head is passed on the end face of printing paper while conducting printing operation in the impact dot head. CONSTITUTION:A nose guide 18 holding a front end guide 6 is supported in a rockable manner in the direction of a printing column, and coil springs 31 are arranged between a nose 1 and the nose guide 18. Accordingly, the nose guide 18 can be displaced angularly even under conditions, in which a printing region is set erroneously, printing operation is started from a position displaced from printing paper and an impact dot head is passed on the end face of printing paper while conducting printing operation, thus preventing the breaking of a wire.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head for an impact dot matrix printer.

[0002]

2. Description of the Related Art FIG. 1 shows a conventional impact dot head.
7, shown in FIG. As shown in FIG. 17, the impact dot head protrudes the wire 8 while moving in a direction perpendicular to the plane of the drawing in parallel with the platen 12, and gives an impact force to the printing paper 19 on the platen 12 via the ink ribbon 21. A printing element that forms dots. Here, the wires 8 are slidably arranged and supported by the intermediate guide 7 and the tip guide 6 in order to form dots at predetermined positions on the printing paper 19.

As a method of attaching the tip guide 6 to the head body, a method proposed in Japanese Patent Laid-Open No. 2-530 is known. This impact dot head is shown in Figure 1.
As shown in FIG. 8, the tip guide 6 and the intermediate guide 7 are inserted into the nose guide 18, and the nose guide 18 has an oval window portion that fits the shape of the tip guide 6 inserted into the nose guide 18. It is attached to a metal nose 1 provided with 30. The position of the tip guide 6 is determined by positioning the tip guide groove 23 of the nose guide 18 in the direction perpendicular to the printing paper.
In the direction parallel to the printing paper, the oblong window portion 30 of the nose 1 is used.

[0004]

In the impact dot printer, when the print area is erroneously set and the print operation is started from a position deviated from the print paper, the impact dot head moves the end surface of the print paper while performing the print operation. There is a phenomenon that the wire 8 is broken under the condition of passing.
In recent years, the diversification of printing paper has advanced, printing has started to be performed on thick printing paper such as thick paper and copy slips with a large number of sheets, and wire breakage frequently occurs at the end face of the printing paper, which is a problem. Was there. The mechanism of wire breakage that occurs when the impact dot head passes through the end face of the printing paper while performing the printing operation will be described below. FIG. 19 is a plan view in section F of FIG. As shown in FIG. 19, when the impact dot head starts the printing operation from the position deviated from the printing paper 19, and the wire 8 is driven while moving from the left to the right in the figure to jump out and pass the end surface of the printing paper 19. ,
The wire 8 collides with the end surface of the printing paper 19 and receives the force A. As a result, the wire 8 is bent, and the wire 8 receives the reaction force B from the guide hole 32 provided in the tip guide 6. here,
When the coefficient of friction between the wire 8 and the ink ribbon 21 is α and the coefficient of friction between the wire 8 and the tip guide 6 is β, the wire 8
Friction forces C and D act on the wire 8 in the direction opposite to the returning direction of. These frictional forces C (= αA) and D (= β
B) prevents the return operation of the wire 8 and
The impact dot head continues to move from the left side to the right side in the figure in a state where the wire pops out, so that the wire 8 is further bent. As a result, if the bending stress of the wire 8 exceeds the permissible stress, the wire 8 will be broken, and thereafter, dots will be missing and normal printing cannot be performed.

In FIG. 19, the case where the printing operation is performed rightward from the position deviated from the left end of the printing paper has been described as an example, but the printing operation is performed leftward from the position deviated from the right end of the printing paper. The same applies to the case.

As a method of avoiding the above-mentioned wire breakage in the conventional impact dot head, there is a method of significantly increasing the restoring force of the restoring spring 15 shown in FIG. 17 so as to exceed the frictional force C + D. However, due to the large restoring force, a very large driving current is required to obtain a sufficient printing force. Therefore, there is a problem that the power supply capacity must be increased, and the heat generation of the head also increases with an increase in the drive current, and the impact dot head passes the end surface of the print paper while printing. The wire breakage that occurred during the operation was practically unavoidable. The present invention has been made to solve the above-mentioned conventional problems. The printing area is erroneously set, the printing operation is started from a position deviated from the printing paper 19, and the impact dot head performs the printing operation. It is an object of the present invention to provide a highly reliable impact dot head in which wire breakage does not occur even when passing through the end face of 19.

[0007]

In order to solve the above problems, the impact dot head of the present invention is characterized in that the wire has a spring property and can swing in the print digit direction. Also, a tip guide that slidably supports the wire,
It is characterized in that it has a nose guide that supports this tip guide and a nose that houses this nose guide, and that the nose guide can be swung with a spring property with respect to the nose. Further, it is characterized in that it has a nose guide for supporting the tip guide and a nose for accommodating the nose guide, and an elastic member provided on the nose guide is brought into contact with the inner wall of the nose. Further, it is characterized in that it has a nose guide for supporting the tip guide and a nose for accommodating the nose guide, and an elastic member provided on the tip guide is brought into contact with the inner wall of the nose. Further, it has a nose guide for supporting the tip guide and a nose for accommodating the nose guide, and the convex or concave portion provided on the nose guide and the concave or convex portion provided on the nose are engaged to form a swing center. It is characterized by In addition, it has a nose guide that supports the tip guide, a nose guide base that supports this nose guide, and a nose that houses the nose guide.The protrusion or recess provided on the nose guide and the recess or protrusion provided on the nose guide base. It is characterized in that the rocking center is formed by engaging the parts.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a side view of an impact dot head of the present invention, FIG. 2 is a front view, FIG. 3 is a plan view as seen from E in FIG. 1, and FIG. 4 is a sectional view showing a section FF in FIG. A printed wiring board 10 is arranged on the frame 2 via an insulating member 9. The frame 2 has a cylindrical shape, and a plurality of frame core portions 14 are erected parallel to each other from the bottom surface thereof. The coil 20 is inserted in the frame core portion 14 and is connected to the printed wiring board 10. A spring holder 13 is attached to the inner ring portion 11 of the frame 2. The spring holder 13 is equipped with the same number of return springs 15 as the frame core portion 14, and at the same time, the spring holder 13 is attached.
A guide groove provided in the guides the tip of the lever 16. Next, the first yoke 3 and the second yoke 4 are attached to the upper surface of the frame 2 (on the left side in FIG. 4).
A lever 16 facing the frame core portion 14 is positioned by the yoke 3 and the second yoke 4. The wire 8 is fixed to the tips of these levers 16 and is urged by the return spring 15 in the return direction. The ends of the wires 8 are arranged at predetermined positions by the tip guide 6.
The top surface of the spring holder 13 (on the left side in FIG. 4)
The damper holder 5 is attached to the damper holder 5, and the damper 17 is attached to the center of the damper holder 5, and the rear end portion of the lever 16 is in contact with the damper 17. At the same time, a fulcrum pressing spring 22 is attached to the damper holder 5, and elastically supports the fulcrum portion of the lever 16.

In such a structure, the coil 20 connected to the printed wiring board 10 is selectively energized according to a print signal, and the magnetic flux excited by the coil 20 is the frame core portion 14, the frame 2, and the first yoke 3. , The second yoke 4, the lever 16 and the loop returning to the frame core portion 14. As a result, the frame core portion 14 and the lever 1
A magnetic attraction force acts between the wire 16 and the lever 16 to advance the lever 16, and the wire 8 fixed to the tip of the lever 16 gives an impact force to the printing paper 19 on the platen 12 via the ink ribbon 21 to form dots. After the dot formation, the lever 16 shifts to the returning operation by the spring force of the returning spring 15, collides with the damper 17 supported by the damper holder 5, and returns to the standby state.

An example of a structure for supporting the wire 8 with a spring property, which is a characteristic structure of the present invention, is shown below. Figure 5
FIG. 4 is an exploded perspective view of the nose guide portion and the nose. A tip guide groove 23 is provided in the nose guide 18, and the tip guide 6 is held by the tip guide groove 23, and the tip guide 6 arranges wires 8 (not shown) at predetermined positions. Further, the nose guide 18 has an intermediate guide groove 24.
Is provided, and the intermediate guide 7 is held by the intermediate guide groove 24. A hole 25 penetrating in the vertical direction is provided at the end of the nose guide 18, and a portion projecting vertically in the nose guide 18 is provided in the nose guide base 26, and a hole 27 corresponding to the hole 25 is provided therein. Has been. Nose guide 18 and nose guide base 26 have holes 2
5 and the pin 27 are inserted into the hole 27 so as to be swingably combined. A nose guide unit 29, which is a combination of the nose guide 18 and the nose guide base 26, is inserted into the nose 1. At this time, the tip guide 6 held by the nose guide 18 is inserted into the window 30 of the nose 1, but the window 30 only guides the upper and lower ends of the tip guide 6 slidably. The end has a gap with respect to the window portion 30 of the nose 1. Nose guide 18
A coil spring 31 is provided on the left and right between the nose 1 and
As shown in FIGS. 2 and 3, in the normal state, the tip guide 6
The nose guide unit 29 is elastically supported in the left-right direction in FIG. 2, that is, in the print digit direction so that is located at the center of the window portion 30 of the nose 1.

In a printer having an impact dot head having such a configuration, the printing area is erroneously set, the printing operation is started from a position deviated from the printing paper, and the impact dot head is moved to the printing paper 19 while performing the printing operation. The case of passing through the end face will be described with reference to FIG. FIG. 6 is a plan view of the section G in FIG. 4, showing a state in which the impact dot head starts the printing operation from a position deviated from the printing paper 19 and the wire 8 is driven and popped out while moving from left to right in the drawing. When passing the end surface of the printing paper 19, the wire 8 collides with the end surface of the printing paper 19 and receives the force A. As a result, the wire 8 presses the guide hole 32 provided in the tip guide 6 to the left, and the wire 8 receives the reaction force B against it. The pressed tip guide 6 deforms the coil spring 31 of FIG. 5 via the nose guide 18, and the nose guide 18 is angularly displaced about the pin 28. Assuming that the coefficient of friction between the wire 8 and the ink ribbon 21 is α and the coefficient of friction between the wire 8 and the tip guide 6 is β, the frictional force C ( = ΑA) and D (= βB) act, the forces A and B are reduced by the angular displacement of the nose guide 18, and as a result, the frictional forces C and D are reduced. Therefore, even when the impact dot head passes through the end face of the printing paper 19 with the wire 8 jumping out, the wire 8 can return to the standby state without being broken. On the other hand, after passing through the end face of the printing paper 19, the nose guide 18 returns to the center of the window portion 30 of the nose 1 by the coil spring 31, so that the wire 8 returns to the predetermined position in the printing digit direction, and the conventional impact dot head. It is possible to maintain high print quality similar to.

The tip guide 6 is preferably made of a material having a small coefficient of friction, such as polyacetal, polypropylene, tetrafluoroethylene fiber-added resin, or oil-containing resin. This is because when the friction coefficient β of the material is small, the frictional force D can be further reduced, and an impact dot head with higher wire breakage resistance can be achieved.

In FIG. 7, a leaf spring 3 is used instead of the coil spring 31.
An example using No. 3 will be shown. The leaf spring 33 is the nose guide 1
Since it is sandwiched and fixed in the groove portion 34 provided in 8, the structure is simpler than that of the coil spring and the assemblability is improved.

FIG. 8 shows an embodiment in which the tongue-shaped spring portion 35 is provided integrally with the tip guide 6 instead of the coil spring 31. In this embodiment, since the tip guide 6 and the tongue-shaped spring portion 35 are integrally formed, it is easy to manage the component dimensions.

FIG. 9 shows an embodiment in which the tongue-shaped spring portion 36 is provided integrally with the nose guide 18. Since it is integrally formed, the dimensional control of the parts is facilitated, and the projection 37 at the tip of the tongue-shaped spring portion 36 is brought into contact with the inner wall of the nose 1 so that the tongue-shaped spring portion 36 projects from the nose guide 18. Since there is no leaf spring, the spring will not be deformed when handling parts unlike when using a leaf spring.

FIG. 10 shows an embodiment in which a sponge 38 is held in the gap between the nose guide 18 and the nose 1. The elastic force of the sponge 38 is used as a spring, and ink ribbon waste and paper dust do not enter the gap between the nose 1 and the nose guide 18 so as to prevent the movement of the nose guide 18.

FIGS. 11, 12 and 13 show an embodiment of a swing fulcrum portion, which is constructed by engaging a convex portion provided on the nose guide 18 with a hole or a concave portion provided on the nose guide base 26. Indicates.

FIG. 11 shows a structure in which the convex portions 39 provided at the upper and lower two locations on the central axis of the nose guide 18 are fitted into the C-shaped convex receivers 40 provided at the upper and lower two locations on the central axis of the nose guide base 26. The convex receiver 40 is elastically deformed to fit the convex portion 39. With this method, the pin 28 becomes unnecessary,
Cost can be reduced.

In FIG. 12, elastic arms 41 are arranged at two upper and lower positions on the center axis of the nose guide 18, and a convex portion 42 is provided at the tip of each elastic arm 41. The nose guide base 26 is provided with holed convex receiving portions 43 at two upper and lower positions on the center axis. The elastic arms 41 of the nose guide 18 are bent to insert the convex portions 42 into the holes of the convex receiving portion 43. .

In the embodiment shown in FIG. 13, an elastic arm 41 is arranged above the center axis of the nose guide 18, and a convex portion 42 is provided at the tip of this elastic arm 41. On the other hand, on the central axis of the nose guide base 26, a convex receiving portion 43 with a hole is formed above.
The elastic arm 41 of the nose guide 18 is bent to insert the convex portion 42 into the hole of the convex receiving portion 43 to form a swing fulcrum. A leg portion 44 is provided below the center axis of the nose guide 18 and abuts on a leg receiving plate 45 provided below the center axis of the nose guide base 26. The leg portion 44 supports the nose guide 18 in the vertical direction, prevents the convex portion 42 from coming off the convex receiving portion 43, and at the same time, can slide on the leg receiving plate 45. it can. FIG. 14 shows a detailed view of the leg receiving plate 45. Thus, the arc-shaped groove 46 centered on the swing fulcrum
Is provided on the leg receiving plate 45, and the convex portion 48 corresponding to the groove 46 is provided on the nose guide 18. According to this structure, since the convex portion 48 is guided by the groove 46, a stable swinging motion around the swinging fulcrum is performed on the leg portion 44 side of the nose guide 18 as compared with the case where the convex portion 48 and the groove 46 are not provided. Can be made. FIG. 15 shows a detailed view of the convex receiving portion 43 of FIG. As shown, a guide groove 47 is provided in the hole of the convex receiving portion 43. Further, the protruding length of the leg receiving plate 45 from the nose guide base 26 is set longer than the protruding length of the convex receiving portion 43 from the nose guide base 26. In such a structure, when attaching the nose guide 18 to the nose guide base 26, first, the leg portion 44 of the nose guide 18 is placed on the leg receiving plate 45. Next, the convex portion 42 is inserted into the guide groove 47 while sliding the leg portion 44 on the leg receiving plate 45. Since the convex portion 42 is bent along the slope of the guide groove 47 and enters the hole of the convex receiving portion 43, the assembling property can be improved.

Although FIG. 11, FIG. 12, and FIG. 13 described above show an embodiment in which the convex portion provided on the nose guide 18 and the hole or concave portion provided on the nose guide base 26 are engaged with each other,
On the contrary, the nose guide 18 is provided with a hole or a recess,
It may be configured by engaging a convex portion provided on the nose guide base 26.

FIG. 16 shows an embodiment in which the nose guide base 26 is not used. As shown in the figure, convexes are provided on the upper and lower sides of the window portion into which the nose guide 18 of the nose 1 is inserted, and the convex portion of the nose 1 provided on the nose guide 18 is engaged with the C-shaped receiving portion, and the swing fulcrum is You may comprise.

Although the direct attraction type impact dot head has been described above as an example, it is obvious that the present invention can be applied to a spring charge type or a piezoelectric type impact dot head.

[0024]

As described above, in the print head of the present invention, since the wire is supported so as to be swingable in the print digit direction with a spring property, the print area is erroneously set and is displaced from the print paper. Even if the impact dot head starts the printing operation from the position and the impact dot head passes through the end face of the printing paper while performing the printing operation, there is an effect that a highly reliable impact dot head is obtained in which wire breakage does not occur.

[Brief description of drawings]

FIG. 1 is a side view of an impact dot head according to the present invention.

FIG. 2 is a front view of an impact dot head of the present invention.

FIG. 3 is a plan view of the impact dot head according to the present invention as viewed from E.

FIG. 4 is a sectional side view of the impact dot head taken along line FF of the present invention.

FIG. 5 is an exploded perspective view showing a nose guide portion and a nose of the present invention.

FIG. 6 is a plan view showing a state where a front end guide portion of the present invention passes through an end surface of printing paper.

FIG. 7 is an exploded perspective view showing a nose guide portion of the present invention.

FIG. 8 is an exploded perspective view showing a nose guide portion of the present invention.

FIG. 9 is an exploded perspective view showing a nose guide portion of the present invention.

FIG. 10 is an exploded perspective view showing a nose guide portion of the present invention.

FIG. 11 is an exploded perspective view showing a nose guide base portion of the present invention.

FIG. 12 is an exploded perspective view showing a nose guide base portion of the present invention.

FIG. 13 is an exploded perspective view showing a nose guide base portion of the present invention.

FIG. 14 is a perspective view showing a leg receiving plate of the nose guide base of the present invention.

FIG. 15 is a perspective view showing a convex receiving portion of the nose guide base of the present invention.

FIG. 16 is an exploded perspective view showing a nose guide portion of the present invention.

FIG. 17 is a sectional side view showing a conventional impact dot head.

FIG. 18 is an exploded perspective view showing a conventional nose guide portion.

FIG. 19 is a plan view showing a case where a conventional leading end guide portion passes through an end surface of printing paper.

[Explanation of symbols]

 1 Nose 2 Frame 3 First Yoke 4 Second Yoke 5 Damper Holder 6 Tip Guide 7 Intermediate Guide 8 Wire 9 Insulation Member 10 Printed Wiring Board 11 Frame Inner Ring Part 12 Platen 13 Spring Holder 14 Frame Core Part 15 Return Spring 16 Lever 17 Damper 18 Nose guide 19 Printing paper 20 Coil 21 Ink ribbon 22 Support point pressing spring 23 Tip guide groove 24 Intermediate guide groove 25 Nose guide hole 26 Nose guide base 27 Nose guide base hole 28 Pin 29 Nose guide unit 30 Nose window 31 Coil spring 32 Guide hole 33 Leaf spring 34 Leaf spring fixing groove 35 Tip guide tongue spring 36 Nose guide Tongue spring 37 Tongue spring convex 38 Sponge 39 Nose guide convex 40 C-shaped convex receiver 41 Elastic arm 4 2 Nose guide convex part 43 Convex receiving part 44 Leg part 45 Leg receiving part 46 Leg receiving part groove 47 Convex receiving part guide groove 48 Convex part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minoru Tanaka 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation

Claims (6)

[Claims] 1. An impact dot head that prints by selectively projecting a wire while moving in the print digit direction, wherein the wire is supported so that the wire can swing in the print digit direction. Characteristic impact dot head. 2. A tip guide for slidably supporting the wire, a nose guide for supporting the tip guide, and a nose for accommodating the nose guide. The nose guide is springy with respect to the nose. The impact dot head according to claim 1, wherein the impact dot head is capable of swinging. 3. A nose guide for supporting the tip guide and a nose for accommodating the nose guide, wherein an elastic member provided on the nose guide is in contact with an inner wall of the nose. Impact dot head. 4. A nose guide for supporting the tip guide and a nose for accommodating the nose guide, wherein an elastic member provided on the tip guide is in contact with an inner wall of the nose. Impact dot head. 5. A nose guide for supporting the tip guide, and a nose for accommodating the nose guide, wherein a convex or concave portion provided on the nose guide and a concave portion or convex portion provided on the nose are engaged with each other. The impact dot head according to claim 1, wherein a swing center is formed. 6. A nose guide for supporting the tip guide, a nose guide base for supporting the nose guide,
A nose for accommodating the nose guide is provided, and a convex or concave portion provided on the nose guide and a concave or convex portion provided on the nose guide base are engaged with each other to form a swing center. 1 impact dot head.