JPH0469549B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing hammer used in a printing head of a printer, and particularly to a printing hammer using a piezoelectric element as a driving source.

[Conventional technology]

An electromagnetic actuator is widely used as a driving source for printing hammers used in print heads of conventional printers. Such an electromagnetic actuator is configured to generate a magnetic field by passing a current through a coil, and drive a movable member using the resulting magnetic force. For this reason, copper loss and iron loss occur, which not only requires a large amount of input energy, but also causes problems such as heat generation and magnetic interference.

For this reason, a printing hammer is being considered that uses a piezoelectric element as a driving source, which has high electrical/mechanical energy conversion efficiency, can be driven with low power, generates little heat, and is free from magnetic interference. For example, there is a printing hammer as shown in FIG.

The printing hammer shown in FIG. 5 has a piezoelectric element 51 whose lower end is connected to a fixing member 50, and two first and second connecting parts 52 and 53 at the lower end, one of which is connected to a fixing member 50. The connecting portion 52 is the fixing member 50
The other coupling portion 53 is connected to the piezoelectric element 51.
It has a first arm 54 coupled to the upper end, and two third and fourth coupling parts 55 and 56 that are close to each other in the vertical direction, one coupling part 55 of which is coupled to the upper end of the arm 54. The other coupling portion 56 includes a second arm 57 coupled to the upper side of the fixing member 50 and a printing wire 58 fixed to the left end of the arm 57.

FIG. 5a is a diagram showing a state in which no voltage is applied to the piezoelectric element 51 (inoperative state), and FIG. 5b is a diagram showing a state in which a voltage is applied to the piezoelectric element 51 (operating state). .

When a voltage is applied to the piezoelectric element 51 in the state shown in FIG. 5a, as shown in FIG. 5b, the piezoelectric element 5
1 extends in the direction of arrow A, whereby the first arm 54 is pushed to the right at its lower end and rotates in the direction of arrow θ ₁ about the joint 52 as a fulcrum. Piezoelectric element 51
The amount of displacement is magnified by the lever principle and transmitted to the joint 55. Therefore, the arm 57 is pulled at the connecting portion 55 and rotates in the direction of arrow θ ₂ using the connecting portion 56 as a fulcrum. As a result, the connecting portion 5
The displacement amount of 5 is also magnified and transmitted to the printing wire 58 by the lever principle. In this way, the piezoelectric element 5
The displacement amount of 1 is magnified by the rotational movement of the arms 54 and 57, and is transmitted to the printing wire 58 to perform a printing operation.

[Problem that the invention seeks to solve]

The conventional print head mentioned above uses a piezoelectric element as a driving source, so it has the advantage of low power consumption, low heat generation, and no magnetic interference. The displacement amplification mechanism for this purpose is a two-stage amplification type in which a structure that performs a lever action with one arm and two coupling parts is connected in series in two stages. It serves as a displacement magnification mechanism. For this reason,
Conventional printing hammers have a problem in that they have a complicated structure and are expensive to manufacture.

Moreover, since such a displacement amount enlarging mechanism applies the principle of a lever, it has the property that the displacement amount is increased but the force is reduced. Therefore, it is difficult for the first stage displacement magnification mechanism, which is composed of the first arm and the first and second coupling parts, to obtain a large force as its output.
It is necessary to make the bending rigidity of the third and fourth joints of the second stage displacement magnification mechanism smaller than the bending rigidity of the first and second joints. As a result, the natural frequency of the second stage displacement magnification mechanism, which is composed of the second arm and the third and fourth coupling parts, becomes low, and as a result, the response frequency of the printing operation of the printing hammer becomes high. There is also the problem that the printing speed cannot be increased because the printing speed is not high.

An object of the present invention is to improve the drawbacks of the conventional printing hammer using a piezoelectric element as a driving source as described above, and to provide a printing hammer that has a simple structure, is inexpensive to manufacture, and can operate at high speed. It's about doing.

[Means for solving problems]

The printing hammer of the present invention includes an arm having a printing wire fixed to one end, and one end of which is fixed to the center of the other end of the arm, and the width of the arm is fixed in a direction perpendicular to the direction of movement of the printing wire. a piezoelectric element having one end fixed to the other end of the first hinge and the other end fixed to a fixing member; and a piezoelectric element fixed in the width direction of the first hinge. are arranged on the left and right sides of the arm and have equal steps of predetermined dimensions in the direction of movement of the printing wire with respect to the first hinge, one end of which is fixed to the other end of the arm, and the other end is fixed to the other end of the arm. It is configured to include second and third hinges in the form of thin plates fixed to the fixing member.

[Effect]

The printing hammer of the present invention includes a thin plate-shaped first hinge which is a main member for connecting an arm carrying a printing wire and a thin plate, and a thin plate-shaped first hinge provided on both sides in the lateral direction (width direction) with this hinge in between. , is provided with thin plate-like second and third hinges that are arranged to have a predetermined height difference from the first hinge in the height direction, and the center line of the first hinge and the second and the center line of the third hinge is shortened compared to the distance between the hinges when each conventional hinge is arranged in a plane. As a result, the displacement magnification rate of one displacement magnification mechanism can be increased, so that the operation amount (stroke) of the printing wire necessary for the printing operation can be obtained with only one stage amplification using only one arm.

Therefore, compared to the conventional two-stage amplification using two arms, the equivalent mass of the arm is smaller. Furthermore, since the bending rigidity of the hinge portion is increased, the natural frequency of the displacement magnification mechanism is increased, and the response frequency of the printing operation of the printing hammer is therefore increased, so that a printing hammer capable of high-speed operation can be obtained.

Further, since the displacement amount enlarging mechanism is also composed of only one arm and three hinges, the structure of the printing hammer becomes simple and an inexpensive printing hammer can be obtained.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing a first embodiment of the present invention;
2 is an enlarged perspective view showing the arrangement of hinges in the embodiment shown in FIG. 1, and FIG. 3 is a perspective view showing the operating state of the embodiment shown in FIG.

In FIG. 1, an arm 1 has a thin plate-shaped first hinge 2 at its end 1a, and thin plate-shaped second and third hinges 3 and 4 provided on both sides of the hinge in the lateral direction (width direction). have. The first hinge 2 is
It is connected to the end surface of one end 5a of the piezoelectric element 5 in the direction of expansion and contraction (arrow B), and the second and third hinges 3
and 4 are coupled to the end surface of the fixing member 6. The other end 5b of the piezoelectric element 5 in the expansion/contraction direction is also coupled to the fixing member 6. Other end 1 of arm 1
A printing wire 7 is connected to b.

FIG. 2 is a perspective view showing details of the arrangement of the first, second, and third hinges 2, 3, and 4 of the embodiment shown in FIG. Second and third hinge 3
and 4 are provided on both the left and right (width direction) sides of the first hinge 2, and are offset from the position of the first hinge 2 in the height (thickness) direction, with a step of a predetermined dimension. have. The second hinge 3 and the third hinge 4 are arranged at the same height.

When a voltage is applied to the piezoelectric element 5 of the printing hammer having such a configuration, the operation shown in FIG. 3 is performed. That is, the piezoelectric element 5 expands in the direction of arrow B1 and displaces the first hinge 2 in the direction of arrow B1. On the other hand, one end of the second and third hinges 3 and 4 is fixed to the fixing member 6, and the other end is fixed to the arm 1, and since there is a step between them and the first hinge 2, the thin plate-like first and third hinges The second and third hinges 2, 3, and 4 undergo bending deformation in the direction of arrow C, and the arm 1 also causes rotational movement in the direction of arrow C. As a result, the printing wire 7 connected to the tip of the arm 1 is transmitted with the amount of displacement of the piezoelectric element 5 magnified, and moves in the direction of arrow D to perform a printing operation.

In this way, in the printing hammer of this embodiment, the second and third hinges 3 and 4 are provided on both sides of the first hinge 2 in the lateral direction (width direction), and the height (thickness) direction is Position the first hinge 2
The distance between the center line of the first hinge 2 and the center lines of the second and third hinges 3 and 4 can be reduced by arranging the center lines of the first hinge 2 and the center lines of the second and third hinges 3 and 4 to can be shortened compared to a planar arrangement. As a result, the displacement magnification rate of the displacement magnification mechanism can be increased, so even if only one arm is used, the operation amount (stroke) necessary for the printing operation can be given to the printing wire.

Therefore, compared to the conventional case where two arms are used, the equivalent mass of the arm is smaller, so the natural frequency of the displacement magnification mechanism becomes higher, and the response of the printing operation of the print head becomes smaller. A printing hammer capable of high-speed operation is obtained by increasing the frequency.

Further, as described above, since the displacement amount enlarging mechanism is composed of one arm and three hinges, the structure is simple and an inexpensive printing hammer can be obtained.

FIGS. 4a and 4b are a plan view and an
It is an X-ray cross-sectional view.

In FIG. 4, each of the plurality of arms 41 has a thin plate-like first hinge 42 at its end 41a.
and two thin plate-shaped second and third hinges 43 and 44 provided on both sides in the width direction (lateral direction). The first hinge 42 is coupled to one end of a correspondingly provided piezoelectric element 45 in the expansion/contraction direction, and the second and third hinges 42
3 and 44 are coupled to the end surface of the fixing member 46. The other end 45b of the piezoelectric element 45 in the expansion/contraction direction is also coupled to the fixing member 46. each arm 4
A printing wire 47 is connected to the other end 41b of each of the printing wires 1.

The fixing member 46 is a single member and is commonly used for all printing hammers. That is, it is a part of the member constituting the main printing head, and is provided corresponding to the second and third hinges 43 and 44 of all the printing hammers, and is configured to fix each of them. Therefore, the second and third hinges 43 and 44 of each printing hammer are connected at one end to the end 41a of the respective corresponding arm 41, and at the other end to the common fixing member 4.
It is fixed at 6. In addition, all piezoelectric elements 4
5 is also fixed to this one common fixing member 46.

The positional relationship between the first hinge 42, the second hinge 43, and the third hinge 44 is the same as that in the embodiment shown in FIG.
are provided on both sides of the first hinge 42 in the width direction, and are arranged at the same height with a step between them and the first hinge 42 in the thickness direction.

Each print hammer of the print head configured in this manner operates in the same manner as the print hammer of the first embodiment, and therefore provides similar effects.

〔Effect of the invention〕

As explained above, the print head of the present invention has
Since the structure is simple, it can be manufactured at low cost, and since the response frequency is high, high-speed printing operation can be performed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the present invention;
2 is an enlarged perspective view showing the arrangement of the hinge in the embodiment shown in FIG. 1, FIG. 3 is a perspective view showing the operating state of the embodiment shown in FIG. 1, and FIGS. FIG. 5 is a side view showing an example of a conventional printing hammer, in which a is a diagram showing a non-operating state, and b is a side view showing an example of a conventional printing hammer. is a diagram showing the operating state. 1,41,54,57...Arm, 2,42...First hinge, 3,43...Second hinge, 4,44...Third hinge, 5,45,51...Piezoelectric element, 6,4
6, 50... Fixing member, 7, 47, 58... Printing wire, 52, 53, 55, 56... Connection portion.

Claims (1)

[Claims] 1. An arm having a printing wire fixed to one end thereof, and one end of the arm fixed to the center of the other end of the arm, the width direction of which is arranged perpendicular to the direction of movement of the printing wire. a thin plate-shaped first hinge; a piezoelectric element having one end fixed to the other end of the first hinge and the other end fixed to a fixing member; and arranged on the left and right sides of the first hinge in the width direction. and has an equal step of a predetermined size in the movement direction of the printing wire with respect to the first hinge, one end of which is fixed to the other end of the arm, and the other end is fixed to the fixing member. A printing hammer characterized by comprising second and third hinges in the form of thin plates.