JP3054772B2 - Impact dot head - Google Patents

Description

The present invention relates to a print head for an impact dot printer.

(Prior art) The armature is magnetically attracted to the end face of the coil core,
A print head of a so-called impact dot type printer, in which a wire at the tip of the armature is hit against recording paper to perform recording and writing, usually has a damper receiving surface on the lever holder, and the armature that has returned to the non-printing position By contacting the damper receiving surface, the gap between the armature and the core, that is, the stroke of the print lever is made constant and the contact force is made constant, so that recording and writing with a constant density can be performed.

However, in general, this type of head employs a configuration in which a yoke is superimposed on an outer peripheral wall of a frame, a base end portion of a print lever is placed on the yoke, and pressed and held by a peripheral portion of the lever holder from above. Due to this, the thickness unevenness in the range of the tolerance of the yoke and the lever holder, the bending thereof, and the like accumulate, causing a problem that the stroke of the print levers varies between the print levers.

(Problems to be Solved by the Invention) The present invention has been made in view of such a problem, and it is an object of the present invention to provide an excellent assemblability and to make the lever stroke of each print lever uniform. It is to provide a new impact dot head.

(Means for Solving the Problems) That is, in order to achieve the above object, the present invention provides a frame in which a plurality of cores are protruded in a ring shape between an outer peripheral wall and an inner peripheral wall, and a return spring to always provide a standby direction. A plurality of print levers arranged opposite to each core in a state receiving the urging force, and arranged to cover the frame and the print lever,
And a lever holder having on its inner surface a receiving surface that comes into contact with the print lever at the standby position, wherein the inner surface of the lever holder is in direct or indirect contact with the inner peripheral wall end surface of the frame. A contact surface is formed, and the above-mentioned receiving surface is formed inside the contact surface as a reference surface for lever stroke.

Embodiment An embodiment of the present invention will be described below.

FIG. 1 and FIG. 2 show a typical embodiment of the present invention.

The frame 1 in which a large number of cores 1a protrude in a ring shape,
An outer peripheral wall 1b is integrally formed to protrude so as to surround these cores 1a, and an inner peripheral wall 1c abutting on an inner protruding portion 2b of a lever holder 2 described later is provided inside these cores 1a.
Are integrally formed to protrude.

On the other hand, the lever holder 2 positioned so as to cover the frame 1 has a function of receiving the lever 5 returned by the deenergization of the core 1a.
An outer peripheral projection 2a for pressing and supporting the base end of the lever 5 is integrally formed.
Are integrally formed so as to abut against the inner peripheral wall 1c of the frame 1.

The lever holder 2 is provided with a damper receiver 2d for receiving the lever 5 that has returned to the inside of the inner protrusion 2b.
As shown in the figure, when the step between the inner protrusion 2b and the outer protrusion 2a is Eh, the step Eh is equal to the top surface of the yoke 4 mounted on the outer wall 1b of the frame 1 and the inner surface. Step Ef with peripheral wall 1c
It is formed under a relationship that is larger than that, that is, Eh> Ef.

In the drawing, reference numeral 6 denotes a spring holder holding a return spring 6a, 7 denotes a nose, and 8 denotes a nose.
Indicates a fixing spring for locking the head unit integrally with the locking portion 7a provided on the nose 7.

In the embodiment configured as described above, first, the yoke 4 is mounted on the outer peripheral wall 1b of the frame 1, and then the base end of the lever 5 is mounted thereon, and the lever holder 2 is covered thereon. The distance corresponding to the lever stroke, that is, the axial distance between the end surface of the core 1a and the damper receiver 2d is determined by the inner protrusion 2b of the lever holder 2 being in contact with the inner peripheral wall 1c of the frame 1. It is uniquely determined by the molding accuracy of the inner peripheral wall 1c of the frame 1 and the inner protrusion 2b of the lever holder 2.

Therefore, when the lever holder 2 and the nose 7 are finally fixed by the fixing spring 8, the outer peripheral portion of the lever holder 2 receiving this pressing force is deformed toward the nose 7, and the base end of the lever 5 is moved to the top of the yoke 4. Even if the thickness of the yoke 4 or the lever holder 2 is deviated, as long as the lever 5 has a required forming accuracy, the distance between the armature 5a and the core 1a, That is, these lever strokes are managed uniformly.

In the embodiment shown in FIG. 3, the top surface of each of the inner peripheral wall 1c of the frame 1 and the end surface of the core 1a are formed on the same surface so that they have the same height. The axial distance from the top surface of the core 1a to the damper receiving surface 2d of the lever holder 2 is uniquely determined by the accuracy of forming the inner protrusion 2d.

On the other hand, in the embodiment shown in FIG. 4, the projecting portion 16b mounted on the inner peripheral wall 11c of the frame 11 is formed on the spring holder 16 so as to project outward, and this portion is extended in the axial direction. The lever 15 is provided with a protrusion 15b which directly contacts the outer peripheral wall 11b of the frame 11 through the outer peripheral recess 14a of the yoke 14 while the lever holder supporting protrusion 16c is in contact with the contact surface 12e of the lever holder 12. This portion is configured to be pressed and supported by a fulcrum holding spring 12f provided on the inner peripheral surface of the lever holder 12.

In this embodiment, when the lever holder 12 is covered on the frame 11, before the outer protrusion 12a of the lever holder 12 comes into contact with the base end of the lever 15, the contact surface 12e has a lever holder support protrusion 16c. By contacting the lever holder supporting projection 16c with high precision, the axial dimension between the end face of the core 11a and the damper receiving face 12d, which can determine the lever stroke, can be accurately controlled, and Lever holder 12
The base end of the lever 15 can be correctly pressed onto the outer peripheral wall 11 of the frame 1 by the fulcrum suppressing member 12f.

Note that, in this embodiment, a friction-resistant sheet having a uniform thickness may be interposed on the frame outer peripheral wall 11b, and the fulcrum suppressing member 12f has elasticity instead of the above-described leaf spring. A resin material or a rubber material may be used. By the way, in the above-described embodiment, a step is provided between the damper receiving surface 12d and the holder contact surface 12e, so that dimensional accuracy between them becomes a problem, but as in the embodiment shown in FIG. In addition, by making them the same surface 12g, the dimensional accuracy between the end surface of the core 11a that can determine the lever stroke and this surface 12g depends only on the height accuracy of the lever holder support protrusion 16c. Can be.

6 to 9 relate to means for pressing the base end of the lever 15 against the surface of the yoke 14, and the embodiment shown in FIG. 6 relates to the lever holder supporting projection 16c and the lever holder 1c.
In a state where the contact surface 12e is in contact with the second contact surface 12e, the base end of the lever 15 can be pressed against the upper surface of the yoke 14 with an appropriate pressing force. An elastic member 19 such as a ring is provided. With this configuration, it is unnecessary to deform the outer peripheral portion of the lever holder 12 toward the frame 11 in order to press the base end of the lever 15. Can be.

In addition, as shown in FIG. 7 (b), the elastic member 29 in which the pieces 29a separated by cutting are alternately warped in the opposite direction as shown in FIG. The one shown in FIG. 8 is provided with a ridge-shaped crush boss 22j on the end surface of the outer peripheral protruding portion 22a of the lever holder 22,
The pressing force on the yoke 24 is adjusted according to the degree of the crushing of the crushing point 22j. Further, in FIG. 9, the base end of the lever 25 is connected to the outer periphery of the lever holder 22. An O-ring 29 provided on the protruding portion 22a suppresses this.

Further, in the embodiment shown in FIG. 10, the yoke 34 whose dimensions in the height direction are accurately set is placed on the top surface of the inner peripheral wall 31c of the frame 31, and the inner peripheral projection of the lever holder 32 is placed thereon. 32b
While the abutment of the inner peripheral projection 32b of the lever holder 32 and the abutment of the base end 35c of the lever 35 on the upper surface of the yoke 34 and the outer peripheral end thereof.
39, and the lever 35 is pressed outward by a fulcrum holding member 32f provided on the lever holder 32 for positioning.
As for 39, the lever holder 32 is pressed and supported by an O-ring 32k provided on the top surface of the outer peripheral projection 32a.

In this embodiment, the dimensional accuracy of the inner protruding portion 32c of the lever holder 32 and the damper receiving surface 32d and the dimensional accuracy of the yoke 34 in the height direction allow the lever stroke to be controlled to be constant. Accurate vertical positioning of the base end can also be achieved.

(Effects) As described above, according to the present invention, the contact surface that directly or indirectly contacts the inner peripheral wall end surface of the frame is formed on the inner surface of the lever holder, and the receiving surface that contacts the print lever is formed. Since the lever stroke reference surface is formed inside this contact surface, simply placing the lever holder on the frame automatically creates an axial gap between the print lever and lever receiver that determines the lever stroke. In addition to being able to set this gap uniformly for each print lever, the print quality can be further improved by setting the lever stroke at the tip of the print lever. it can.

[Brief description of the drawings]

FIG. 1 is a sectional view of an impact dot head showing one embodiment of the present invention, FIG.
FIGS. 5 to 9 show another embodiment of the same head, FIGS. 6 to 9 show each embodiment of the pressing means of the lever base end, and FIG. 10 shows another embodiment. It is a figure showing an example. 1, 11 Frame 1b, 11b, 22b Outer wall 1c, 11c, 22c Inner wall 1d, 11d, 22d Lever receiving surface 2, 12, 22 Lever holder 2a, 12a, 22a Outer peripheral projections 2b, 12b, 22b ... Inner peripheral projections 5, 15, 25 ... Lever 6 ... Spring holder

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhiko Nakazawa 3-5-5 Yamato, Suwa-shi, Nagano Inside Seiko Epson Corporation (72) Inventor Masaki Shimomura 3-3-5 Yamato, Suwa-shi, Nagano Say (56) References JP-A-2-281964 (JP, A) JP-A-60-225765 (JP, A) JP-A-1-195057 (JP, A) JP-A-2-188264 (JP JP, A) Japanese Utility Model Showa 60-145044 (JP, U) Japanese Utility Model 2-146033 (JP, U) Japanese Utility Model 2-101739 (JP, U) Japanese Utility Model Showa 62-94843 (JP, U)

Claims (2)

(57) [Claims] 1. A frame having a plurality of cores protruding in a ring shape between an outer peripheral wall and an inner peripheral wall, and disposed opposite to each of said cores while being constantly biased in a standby direction by a return spring. Impact dot head, comprising: a plurality of print levers provided; and a lever holder disposed on the inner surface to cover the frame and the print lever and abutting against the print lever at a standby position. In the inner surface of the lever holder, a contact surface that directly or indirectly contacts the inner peripheral wall end surface of the frame is formed, and the receiving surface is formed inside the corresponding contact surface as a reference surface of a lever stroke. Impact dot head characterized by: 2. A base end portion between an outer peripheral projection of the lever holder and a base end of the printing lever in a state in which the end surface of the inner peripheral wall is in contact with the contact surface. 2. The impact dot head according to claim 1, wherein an elastically deformable member for pressing is interposed.