JPH0691900A - Piezo-electric printing head - Google Patents

Abstract

PURPOSE:To improve a printing quality by stabilizing an action of a piezo-electric element, by a method wherein a piezo-electric printing head is provided with a printing unit holding part, a degree of rigidity of which is improved by providing a U-shaped sectional form. CONSTITUTION:This piezo-electric element head holds a piezo-element 8 by a printing unit holding part 60, a degree of rigidity of which is improved by forming a sectional form in a U-shaped state. Therefore, the piezo-electric element 8 is oscillated, for example, in the direction of an arrow y-Y' and a phenomenon wherein printing is confused is avoided exactly. Since a central round table part 15 to be provided on a ceiling part of a projected part 12 of an inner circumference is formed, the degree of rigidity of which is improved further. Then in a piezo-electric head, a plurality of piezo-electric elements 8 are arranged respectively radially within the printing unit holding part 60, the rigidity of which is improved by providing the U-shaped sectional form. Then since the piezo-electric element 8 is held within the holding part 6 which is constituted of an element holding plate 10, a projected part 11 of an outer circumference and the projected part 12 of the inner circumference, printing can be performed under an extremely stabilized condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric print head mounted on a wire dot printer device.

[0002]

2. Description of the Related Art FIG. 5 is a partially sectional schematic side view showing the structure of a conventional piezoelectric print head, and FIG. 6 is a schematic perspective view thereof.

As shown in FIG. 5, a conventional piezoelectric print head has a lever having one end swingably held by a leaf spring 5 and a printing wire 1 provided at the other end. The portion 3, the piezoelectric element 8 whose posture changes (expands and contracts) in the direction of the arrow U-D by applying a voltage, and the lever portion 3 corresponding to the posture change of the piezoelectric element 8, the arrow U'-D. The printing unit 90 including a drive spring 7 that is swung in the direction ', a printing unit holding member 80 having an L-shaped cross section for holding the printing unit 90, and the wire 1 are arranged so as to face each other. It is configured by a casing 85 that accommodates the plurality of printing units 90.

FIG. 6 is a schematic perspective view showing how these printing units 90 are arranged in the casing 85. As is apparent from FIG. 6, each of the printing units 90 is arranged so that the back surface portion of the printing unit holding member 80 contacts the inner peripheral surface of the casing 85. Although FIG. 6 shows a state in which only one printing unit 90 is arranged in the casing 85, these printing units 90 are arranged along the inner peripheral surface of the casing 85 so that their side surface portions are in close contact with each other. Will be placed.

In this piezoelectric print head, the piezoelectric element 8 extends in the direction of the arrow U by energizing and the lever portion 3
Printing is performed by driving the printing wire 1 provided at the tip of the device in the direction of arrow U ', and when the energization of the piezoelectric element 8 is stopped, the piezoelectric element 8 changes its posture in the direction of arrow D (reduction). Then, the wire returns to the original posture, and accordingly, the wire 1 also returns in the direction of the arrow D'to terminate the printing.

As shown in FIGS. 5 and 6, a conventional piezoelectric print head drives a wire 1 via a leaf spring 5 for rotatably holding a lever portion 3 equipped with the wire 1 and the lever portion 3. The piezoelectric element 8 equipped with the drive spring 7 is held by the vertical portion and the horizontal portion of the printing unit holding member 80 having an L-shaped cross section.

[0007]

As described above, the conventional printing unit 90 is an L-shaped printing having a cantilever structure in which the leaf spring 5 and the drive spring 7 on which the largest stress acts when printing is performed. Since the structure is held by the unit holding member 80, when printing is performed, a portion of the printing unit holding member 80, which holds the piezoelectric element 8, vibrates in the direction of the arrow YY '. This phenomenon is caused by the printing unit holding member.
This is because the cross-sectional shape of 80 is L-shaped as described above and the rigidity is poor. However, it goes without saying that the print quality is adversely affected if the piezoelectric element 8 held by the horizontal portion of the print unit holding member 80 vibrates in the arrow YY 'direction during printing.

Further, as is apparent from FIG. 6, this conventional piezoelectric print head has a high manufacturing cost because each print unit 90 has an independent structure. The present invention is intended to realize a piezoelectric print head whose operation reliability is remarkably improved by having a structure in which a print unit is held by a print unit holding portion having a U-shaped cross section.

[0009]

As shown in FIGS. 1 and 2, the piezoelectric print head according to the present invention has one end rotatably held by a leaf spring 5 and the other end printed. A lever portion 3 equipped with a wire 1 for use, a piezoelectric element 8 whose dimensions change when a voltage is applied, and a drive spring 7 mechanically connecting the piezoelectric element 8 and the lever portion 3 to each other. The configured printing unit section 50, the element holding plate 10 for holding the piezoelectric element 8, and the element holding plate
Cylindrical outer peripheral protrusion 11 provided upright from the outer peripheral end portion of 10, and substantially provided in a form upright from the inner peripheral end portion of the element holding plate 10 in the same direction as the outer peripheral protruding portion 11. A piezoelectric print head is constituted by a print unit holding portion 60 having a U-shaped cross-sectional shape including a cylindrical inner peripheral projection portion 12 and a leaf spring 5 for holding the lever portion 3 swingably. A piezoelectric element 8 arranged on the outer peripheral protrusion 11 side of the printing unit holding portion 60 and swinging the lever portion 3 via the drive spring 7 is arranged on the element holding plate 10 side of the printing unit holding portion 60. Is characterized by.

[0010]

This piezoelectric print head has a structure in which the printing unit holding portion 60 having a U-shaped cross section holds the printing unit portion 50 in order to increase rigidity. Piezoelectric element 8 arranged
The phenomenon that the paper vibrates during printing, for example, in the direction of the arrow YY 'is accurately suppressed. Therefore, this piezoelectric print head has extremely high operational reliability.

[0011]

The present invention will be described in detail below with reference to the drawings of the embodiments. FIG. 1 is a partially sectional schematic side view showing a first embodiment of the present invention, and FIGS. 2A and 2B are partially sectional schematic perspective views showing the first embodiment of the present invention. And a schematic side sectional view, FIGS. 3 (a) and 3 (b) are a schematic perspective view and a schematic side sectional view partially showing a second embodiment of the present invention, and FIG.
FIG. 7 is a schematic side sectional view showing an embodiment of the above, but the same parts as those in FIGS. 5 and 6 are designated by the same reference numerals.

As shown in FIG. 1, the piezoelectric print head according to the present invention has a leaf spring 5 at one end thereof, which has an arrow U'-.
A lever portion 3 which is swingably held in the D'direction and has a printing wire 1 arranged at the other end thereof, and a piezoelectric element whose posture changes in the arrow UD direction by applying a voltage. A plurality of printing unit portions 50 each including an element 8, a piezoelectric element 8 and a drive spring 7 for mechanically connecting the lever portion 3, a donut-shaped element holding plate 10 for holding the piezoelectric element 8; A cylindrical outer peripheral protruding portion 11 is provided upright from the outer peripheral end portion of the element holding plate 10, and an upright shape in the same direction as the outer peripheral protruding portion 11 from the inner peripheral end portion of the element holding plate 10. A printing unit holding portion 60 having a U-shaped cross-section, which is composed of the substantially cylindrical inner peripheral protruding portion 12 and
The piezoelectric print head is constituted by the plate spring 5, and the leaf spring 5 for swingably holding the lever portion 3 is arranged on the outer peripheral projection 11 side of the print unit holding portion 60, and the lever portion 3 is provided via the drive spring 7. The piezoelectric element 8 for oscillating is arranged on the element holding plate 10 side of the printing unit holding portion 60.

As described above, the piezoelectric print head according to the present invention has a structure in which the piezoelectric element 8 is held by the print unit holding portion 60 having a U-shaped cross section to increase the rigidity thereof. A phenomenon in which the piezoelectric element 8 vibrates in the direction of arrow Y-Y 'during printing to disturb the printing is accurately avoided. In the figure, reference numeral 15 denotes a central round table portion provided on the ceiling portion of the inner peripheral projection portion 12, and the rigidity of the printing unit holding portion 60 is further enhanced by forming this central round table portion 15.

FIG. 2A is a perspective view for explaining the structure of this piezoelectric print head (first embodiment). As is clear from FIG. 2 (a), the piezoelectric print head according to the present invention is
A plurality of piezoelectric elements 8 are radially arranged in the print unit holding portion 60 having a U-shaped cross-sectional shape to improve rigidity. Incidentally, in FIG. 2A, each of these printing unit parts 50 is represented by the piezoelectric element 8 as an alternative.

FIG. 2B is a schematic side sectional view showing the structural features of this piezoelectric print head. In this piezoelectric print head, the piezoelectric element 8 constituting the print unit portion 50 is formed by an element holding plate 10, an outer peripheral protruding portion 11, and an inner peripheral protruding portion 12 and has a U-shaped cross-section. Since it is held, the element holding plate 10 does not vibrate, for example, in the direction of the arrow YY 'during printing, and printing can be performed in an extremely stable state.

Next, a second embodiment of the piezoelectric print head according to the present invention will be described with reference to FIGS. 3 (a) and 3 (b). The piezoelectric print head of the second embodiment is provided with the printing unit holding portion 60A in which the outer peripheral projection portion 11 and the inner peripheral projection portion 12 are connected by a plurality of spoke-shaped ribs 30 except for the piezoelectric unit of the first embodiment. Same as the print head.

The spoke-shaped ribs 30 are provided so as to mechanically connect the outer peripheral protrusion 11 and the inner peripheral protrusion 12 like a spoke of a wheel. Therefore, the printing unit holding unit 60
A is the element holding plate 10, the outer peripheral projection 11 and the inner peripheral projection 12
With this, the spoke-shaped ribs 30 form a rectangular cross-section surrounded by the periphery, so that the rigidity is further increased. The spoke-shaped ribs 30 are arranged so as to sew the gaps between the piezoelectric elements 8 as shown in FIG. 3 (a).

Next, a third embodiment of the piezoelectric print head according to the present invention will be described with reference to FIG. The piezoelectric print head of the third embodiment is equipped with a deformable element holding plate 10A having a vibration isolating slit 40 penetrating from the front surface to the back surface thereof as an alternative to the element holding plate 10 for holding a plurality of piezoelectric elements 8. ing. The vibration blocking slit 40 is for blocking the vibration generated when the other piezoelectric elements 8 arranged adjacent to each other are actuated, so that it is possible within a range that does not impair the rigidity of the element holding plate 10A. It is desirable to increase the size as much as possible. When the third embodiment is applied, the printing quality of printing units inevitably improves because the printing unit sections 50 in operation do not interfere with each other.

Since each piezoelectric print head according to the present invention is provided with the printing unit holding portions 60, 60A having a high rigidity, which are constituted by the element holding plate 10, the outer peripheral protruding portion 11 and the inner peripheral protruding portion 12, The operation of the piezoelectric element 8 that drives the printing wire 1 during printing is remarkably stable.

[0020]

As is clear from the above description, the piezoelectric print head according to the present invention is provided with the print unit holding portion having a U-shaped cross-sectional shape so that the rigidity is increased. When the print head is used, especially the operation of the piezoelectric element is stabilized and the print quality is remarkably improved.

[Brief description of drawings]

FIG. 1 is a schematic side view with a partial cross section showing a first embodiment of the present invention.

2A and 2B are a schematic perspective view and a schematic side sectional view, respectively, showing a partial cross section showing a first embodiment of the present invention.

3A and 3B are a schematic perspective view and a schematic side sectional view, respectively, showing a partial cross section of a second embodiment of the present invention.

FIG. 4 is a schematic side sectional view showing a third embodiment of the present invention.

FIG. 5 is a schematic side view showing a structure of a conventional piezoelectric print head with a partial cross section.

FIG. 6 is a schematic perspective view showing the structure of a conventional piezoelectric print head.

[Explanation of symbols]

 1 wire 3 lever part 5 leaf spring 7 drive spring 8 piezoelectric element 10 element holding plate 10A deformable element holding plate 11 outer circumference protruding part 12 inner circumference protruding part 15 center round table part 30 spoke-like rib 40 vibration blocking slit 50 printing unit Part 60, 60A Printing unit holding part 80 Printing unit holding member 85 Casing 90 Printing unit

Claims (4)

[Claims] 1. A lever part (3) having one end swingably held by a leaf spring (5) and a printing wire (1) provided at the other end, and a voltage A piezoelectric element (8) whose dimensions change when applied, and the piezoelectric element
Drive spring that mechanically connects (8) and the lever part (3)
(7) Multiple printing unit parts composed of (50)
An element holding plate (10) for holding the piezoelectric element (8), and a cylindrical outer peripheral projection (11) provided upright from the outer peripheral end portion of the element holding plate (10). Printing unit holder
A piezoelectric print head is constituted by (60), and the other end of the leaf spring (5) is fixed to the outer peripheral projection (11),
A piezoelectric element (8) for swinging the lever portion (3) via the drive spring (7) is attached to the element holding plate of the printing unit holding portion (60).
A piezoelectric print head, which is arranged on the (10) side. 2. A lever part (3) having one end swingably held by a leaf spring (5) and a printing wire (1) provided at the other end, and a voltage (3) A piezoelectric element (8) whose dimensions change when applied, and the piezoelectric element
Drive spring that mechanically connects (8) and the lever part (3)
(7) Multiple printing unit parts composed of (50)
An element holding plate (10) for holding the piezoelectric element (8), a cylindrical outer peripheral protrusion (11) provided upright from the outer peripheral end portion of the element holding plate (10), and an element A substantially cylindrical inner peripheral protrusion provided upright from the inner peripheral end of the holding plate (10)
(12) and a printing unit holding part (60), and a piezoelectric print head is formed, and the other end of the leaf spring (5) is fixed to the outer peripheral projection (11),
A piezoelectric element (8) for swinging the lever portion (3) via the drive spring (7) is attached to the element holding plate of the printing unit holding portion (60).
A piezoelectric print head, which is arranged on the (10) side. 3. The piezoelectric element (8) is formed by connecting the outer peripheral projection (11) and the inner peripheral projection (12) with a plurality of spoke-shaped ribs (30). 3. The piezoelectric print head according to claim 2, further comprising: 4. The element holding plate (10) for holding a plurality of piezoelectric elements (8) is provided with a vibration blocking slit (40) penetrating from the front surface to the back surface thereof. ~ 3
Piezoelectric print head described.