JPH0640120A - Printing head device - Google Patents

Abstract

PURPOSE:To prevent a leak of a noise in a dot impact printing head. CONSTITUTION:A plurality of printing apparatuses 3 each driving a printing wire 7 by a piezoelectric element 10 are radially arranged and fixed on a ring- form support body 4. Before the support body 4 is fixed to the rear surface of a base part 1a of a head body 1 through planar vibration isolating members 24, 27 by a screw 25, the both are positioned and fixed by a positioning pin 22 at a position where positioning holes 20, 21 respectively formed in the base part 1a and the support body 4. In this case, a noise is generated from the printing apparatus 3 by driving the piezoelectric element 10, but a vibration isolating body is interposed between the positioning hole 20 and the periphery of the positioning pin 22, thereby interrupting the transmission of the noise from the support body 4 to the head body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a dot impact print head device in which a print wire is driven in and out by a print mechanism having a driving means such as a piezoelectric element which expands and contracts when a voltage is applied, or an electromagnetic solenoid. More specifically, the present invention relates to a structure for preventing noise of a print head of this type.

[0002]

2. Description of the Related Art As a drive means for a print wire in a dot impact print head, there has been known, for example, Japanese Patent Laid-Open No.
There are an electromagnetic solenoid type as disclosed in JP-A-2-236759, and one using an electrostrictive element such as a piezoelectric element as in JP-A-2-130153.
Since electric energy is applied to these driving means and converted into mechanical motion, various noises such as vibration noise are emitted from the driving means and the operating portion of the printing mechanism. In order to prevent the noise and protect the printing mechanism and the like, the print head is generally provided with a cover body for covering the printing mechanism.

On the other hand, since it is difficult to directly assemble a printing unit in which the printing wire, the driving means and the printing mechanism are assembled in advance to a plurality of head main bodies, the applicant of the present invention has previously filed Japanese Patent Application No. No. 241363, the printing units are radially fixed to one surface of a ring-shaped support by screwing or the like in advance, and the support is brought into contact with the back surface of the head body via a vibration-proof material. , I proposed to screw the head body and the support.

[0004]

By the way, during the assembly work of the print head, in order to prevent the phase arrangement relationship (the order of the arrangement of the print wires, etc.) of the print wires with respect to the head body in the plurality of print units from being disturbed, A positioning hole is formed in the head body and the support body, and a positioning pin made of metal is passed through the hole.

In this case, as described above, even if there is a vibration isolating member interposed between the support and the head main body, the vibration generated by the printing mechanism or the driving means is positioned from the support during the printing operation. Since it is transmitted to the head main body through the pin, there is a problem that the noise prevention effect is reduced.
SUMMARY OF THE INVENTION It is an object of the present invention to solve this problem and provide a print head with a high noise reduction effect.

[0006]

To achieve the above object, according to the present invention, a plurality of printing units for driving a printing wire by a driving means are radially arranged and fixed on a ring-shaped support to fix the printing wire. In a print head provided so as to protrude from the head main body, a vibration-proof material is interposed between the support and the head main body, and a positioning hole for driving a positioning pin is formed in the support and the head main body. A ring-shaped vibration isolator is interposed between the positioning hole and the outer periphery of the positioning pin on either or both of the support body side and the head body side in the positioning hole.

[0007]

EXAMPLE Next, an example in which the present invention is embodied will be described. The basic structure of the print head of this example is, as shown in FIG. 1, a head body 1 having a substantially circular shape in front view and a cover body. 2 and a plurality of printing units 3 radially arranged with respect to the head main body 1 in a space surrounded by the two. In this embodiment, the head body 1 and the cover body 2
Is made of aluminum alloy.

A plurality of (24 in the embodiment) printing units 3 are radially arranged via a metallic ring-shaped support 4 which is attached to the back side of the base 1a of the head body 1, and the base of the head body 1 is arranged. Hollow cylindrical nose portion 8 protruding from 1a to the front
A predetermined number of guide plates 9 for moving and guiding the print wires 7 in each print unit 3 are provided inside, and the tips of the print wires 7 are configured to project and retract from the tips of the nose portions 8.

Each printing unit 3 is mounted on the front and rear piezoelectric elements 10 formed by laminating piezoelectric ceramics in a laminated shape, and at the front end of the piezoelectric elements 10 to expand and contract the movement of the piezoelectric elements 10 for printing. Printing mechanism 1 for transmitting to the wire 7
1 and a support frame 12 extending rearward from the back surface of the head body 1 for supporting the printing mechanism 11 and the piezoelectric element 10. The support frame 12 is the piezoelectric element 10
So as to surround both sides in the longitudinal direction and the rear end of the main strut 1
2a, the sub-column portion 12b, and the rear end portion 12c are integrally formed in a U shape. The sub-column portion 12b may be fixed to the rear end portion 12c by brazing.

When charged by applying a voltage, the piezoelectric element 1
0 expands in the stacking direction (longitudinal direction) and contracts when discharged, and the piezoelectric element 10 contracts due to temperature rise. Therefore, the temperature compensator 13 having a positive temperature expansion characteristic that corrects for this, It is inserted between the rear end portion 12c of the support frame 12 and the rear end of the piezoelectric element 10 and fixed by an adhesive. The printing mechanism 11 has an arm 14 having a substantially triangular shape in a side view formed by brazing the base of the printing wire 7 to the tip, a plate-shaped first leaf spring and a first plate spring extending in parallel in the longitudinal rearward direction of the main support column 12a. A spring body 15 having a substantially "Π" shape in a side view, which is composed of two leaf springs and a rigid connecting portion that connects the ends of both leaf springs.
And a four-bar linkage mechanism 19, which will be described later, and the connecting portion is fitted and fixed to the base end portion of the arm 14 by brazing or the like. The base end of the first leaf spring is connected to the main strut 1
While being brazed and fixed to the side surface of 2a, the base end portion of the second leaf spring is also fixed to the movable element 18 that contacts the front end surface of the piezoelectric element 10 in a pressed state by brazing or the like.

A four-node link mechanism member 19 made of an elastic material such as a spring plate is arranged so as to straddle the other side of the mover 18 and the sub-column 12b. Although not shown, a notch hole having a substantially H-shape in a side view is formed in the wide side plate portion of each of the left and right wide side plate portions. When fixed to the front and back sides by spot welding (also possible by brazing), when the piezoelectric element 10 expands and contracts by applying a voltage, the left and right wide side plates of the four-node link mechanism member 19 elastically deform into a parallelogram shape in side view. The movable element 18 is configured to be movable in parallel along the longitudinal direction of the positionally fixed sub-column portion 12b.

In this way, if the mover 18 is configured to move in parallel along the longitudinal direction of the sub strut portion 12b, in other words, to move linearly in the longitudinal direction of the piezoelectric element 10, laminated bonding of piezoelectric ceramics is performed. Bending force does not act on the surface, and the laminated portion and the adhesive surface do not peel off accidentally. Then, the front surface of the main support column 12a in each of the printing units 3 radially arranged on the ring-shaped support body 4 is aligned with the back surface of the support body 4 and fixed by brazing or screws (not shown). To do.

Reference numerals 20 and 21 denote a base portion 1a of the head body 1.
And a positioning hole formed in the support 4 and
In the embodiment, the diameter of the hole 21 on the side of the support 4 is equal to that of the positioning pin 22, the hole 20 on the side of the base portion 1a is formed larger than the diameter of the positioning pin 22, and a cylindrical shape (ring) is formed between the pin 22 and the outer periphery thereof. The vibration-proof body 23 made of a vibration-proof rubber is shaped to be inserted.

The support 4 and the base 1a of the head body 1 are also provided.
A plate-shaped vibration-proof material 24 made of a vibration-proof rubber is interposed between and, and is fixed by a screw 25. At this time, a ring-shaped anti-vibration member 27 is also interposed in the mounting recess 26 into which the head 25a of the screw 25 is fitted. A metal ring-shaped reinforcing member 28 is fixed to the rear end surface of the support frame 12 of the printing unit 3 arranged radially by beam welding or the like to reduce deformation of each support frame 12 during printing operation. Has been done.

Piezoelectric element 1 in each printing unit 3
The terminal component 29 electrically connected to the external terminal of 0 is attached to the rear end of each support frame 12, and the front end portion of the terminal component 29 penetrates the bottom plate portion 2a of the cover body 2 to form the printed board 30 on the outer surface. A drive signal is transmitted from the controller of the printer so that the piezoelectric element 10 is electrically connected and operates at a predetermined timing.

In this structure, during a normal printing operation, when the piezoelectric element 10 is extended along the longitudinal direction by applying a voltage, a substantially midway portion in the longitudinal direction of the first leaf spring fixed to the main support column 12a is formed. The spring body is oscillated and displaced so as to be the center of rotation, and the displacement amount is transferred to the arm 1 via the connecting portion.
4, the print wire 7 is driven so as to protrude from the nose portion 8.

The silicone rubber 31 (see the alternate long and short dash line in FIG. 1) as a heat radiating medium filled in the inner space surrounded by the cover body 2 has the support frame 12 and the piezoelectric element 10.
The heat generated by driving the piezoelectric element 10 may be transmitted to the cover body 2 by contacting the side surface of the cover body 2. And
The vibration sound generated by the driving of the printing mechanism 11 due to the expansion and contraction of the piezoelectric element 10 is transmitted to the support body 4, and the vibration isolating member 24 is interposed between the base portion 1a of the head body and the support body 4. Further, since the vibration isolating member 27 and the vibration isolating body 23 are respectively interposed at the head portion 25a of the screw 25 and the outer peripheral portion of the positioning pin 22, it is possible to prevent the vibration from being transmitted to the head main body side, and thus the print head. It has the effect of preventing noise.

In the above-described embodiment, the vibration isolator is interposed between the outer periphery of the positioning pin 22 and the positioning hole 20 on the head body side. A vibrating body may be interposed. Further, there may be a plurality of these positioning points. It goes without saying that the present invention can also be applied to a print head that uses another type of drive means such as an electromagnetic solenoid as the drive means for the print wire.

[0019]

As described above, according to the present invention, a plurality of printing units for driving the printing wires by the driving means are radially arranged and fixed on the ring-shaped support, and the printing wires are head main body. In the print head provided so as to protrude from the print head, a positioning pin is driven into a positioning hole formed in the support body and the head main body, so that the mounting phase relationship of the head main body to the print unit is not changed. Assembly work can be performed. Then, while a vibration damping material is interposed between the support and the head main body, one or both of the support body side and the head main body side in the positioning hole is provided between the support pin and the outer circumference of the positioning pin. Since the ring-shaped vibration isolator is interposed, the vibration generated in the printing unit is transmitted from the support to the head main body through the positioning pin during the printing operation. Shut off both with the swing body. Therefore, it is possible to effectively prevent noise from leaking outside the print head.

[Brief description of drawings]

FIG. 1 is a side sectional view of a print head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Head body 1a Base part 2 Cover body 3 Printing unit 4 Support body 7 Printing wire 8 Nose part 10 Piezoelectric element 12 Support frame 20,21 Positioning hole 22 Positioning pin 23 Vibration isolator 24, 27 Vibration isolator 25 Screw 26 Concave Place 31 Silicone rubber

Claims (1)

[Claims] 1. A print head comprising a plurality of print units, each of which drives a print wire by a driving means, is radially arranged and fixed to a ring-shaped support, and the print wires are provided so as to protrude from a head body. A vibration-proof material is interposed between the support and the head body, while a positioning hole for driving a positioning pin is formed in the support and the head body, and the support hole side and the head body side in the positioning hole are formed. A print head device, characterized in that a ring-shaped vibration isolator is interposed between the positioning pin and the outer circumference of either or both of them.