JPH0577449A - Dot impact printing head device - Google Patents

Abstract

PURPOSE:To prevent the generation of noise in a printing head device. CONSTITUTION:A piezoelectric element 14 extended and contracted by the application of voltage and a motion transmission mechanism 9 for transmitting the extension and contraction of the piezoelectric element to a printing wire 7 applying a printing impression to a printing medium are provided to the support frame in a printing unit. The front of the support frame 6 is fixed to a connection support 30 and a damping member 37 is interposed between the connection support 30 and the substrate 1b of a head main body 1 fixing said support 30.

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 print head device in which a print wire is printed by a piezoelectric element which expands and contracts when a voltage is applied.

[0002]

2. Description of the Related Art The applicant of the present invention previously disclosed in Japanese Patent Laid-Open No.
JP-A-52-52, A printing wire for supporting a rear end portion of a piezoelectric element which expands and contracts by applying a voltage, and which is arranged on the front side of the piezoelectric element to dot the expansion and contraction of the piezoelectric element on a print medium. To support the motion transmission mechanism for transmission to
A piezoelectric element is provided with a support frame on the longitudinal side, and a plurality of printing units are arranged so that the front ends of the respective printing wires are projected and retracted from the nose portion of the metal head body to the front end. It was proposed that they be arranged radially on the back surface of the main body and that the front end of the support frame in each printing unit be bolted directly to the head main body.

[0003]

In this structure, vibrations caused by movements of the motion transmitting mechanism at the time of driving the piezoelectric element in each printing unit are directly transmitted to the head main body through the support frame, and are transmitted to the outside of the print head device. There was a problem that it spread as noise. Further, when a large number of printing units are directly attached to the head main body, there is a problem that it is difficult to set the printing units so that the arrangement intervals of the printing units do not change.

The present invention aims to solve the above problems all at once.

[0005]

In order to achieve the above object, the present invention provides a piezoelectric element which expands and contracts when a voltage is applied,
A motion transmitting mechanism for transmitting the expansion and contraction of the piezoelectric element to a print wire for stamping on a print medium, and a motion transmitting mechanism for the rear end portion of the piezoelectric element which is arranged along the side of the piezoelectric element in the longitudinal direction thereof. In a dot impact print head device comprising a plurality of printing units consisting of a support frame that supports the mechanism, the print wires being arranged on the back surface side of the head body so that the front ends of the respective print wires project and retract forward from the head body, The front part of the support frame in the plurality of printing units is fixed to a connection support, and a vibration isolating member is interposed between the connection support and the head main body fixing the connection support.

[0006]

[Embodiments] Next, embodiments embodying the present invention will be described. As shown in FIG. 1, reference numeral 1 denotes a front disk-shaped head body, and the cover 2 is integrally formed from the outer peripheral edge of the substantially disk-shaped bottom plate portion 2a toward the back surface side of the head body 1. The head body 1 and the cover 2 are made of an aluminum alloy.

Reference numeral 4 is a printing unit, and a plurality of (24 in the embodiment) printing units 4 are radially arranged on the back side of the head body 1. On the front surface of the head main body 1, a hollow nose portion 1a in which a predetermined number of guide plates 3 for guiding the printing wires 7 in each printing unit 4 are installed is provided. Further, the arrangement of the 24 print wires 7 at the positions where the tips of the print wires 7 project from the nose portion 1a is arranged in a horizontally long rhombus (diamond shape) in the direction in which the carriage having the print head moves left and right, and the left side of the rhombus. The print wires arranged in the right half are arranged in a state of being vertically displaced by a half pitch with respect to the arrangement pitch of the print wires 10 arranged in half in the vertical direction (paper feed direction). As a result, it is possible to stamp at a fine pitch in the paper feed direction. According to this configuration, since the print wires having different vertical positions are arranged along the carriage movement direction, when printing characters such as a vertical straight line "1", all print wires are printed. Do not drive at the same time.

The printing unit 4 is mounted on the front end of the piezoelectric element 5 and is formed by laminating piezoelectric ceramics in a laminated manner, and is attached to the front end of the piezoelectric element 5 to expand the expansion / contraction motion of the piezoelectric element and transmit it to the printing wire 7. And a support frame 6 extending rearward from the back surface of the head body 1 for supporting the motion transmitting mechanism 9 and the piezoelectric element 5.
The support frame 6 is integrally formed in a U-shape by the main support 6a, the sub support 6b, and the connection 6c so as to surround the left and right sides and the rear end along the longitudinal direction of the piezoelectric element 5. .. In addition, the auxiliary column portion 6b may be fixed to the connecting portion 6c by brazing or welding.

When a voltage is applied, the piezoelectric element 5 expands and contracts in the stacking direction (longitudinal direction), and the piezoelectric element 5 shrinks as the temperature rises. The compensator 26 is inserted between the connecting portion 6c of the support frame 6 and the rear end of the piezoelectric element 5 and fixed by an adhesive. The motion transmitting mechanism 9 converts the expansion and contraction of the piezoelectric element 5 into the rotational motion of the arm 8 so that the amount of forward / backward movement of the printing wire 7 attached to the tip of the arm 8 is increased. The motion transmission mechanism 9 for this purpose uses an Eden spring composed of two parallel plate-shaped drive spring bodies. That is, the drive spring body is formed by integrally connecting one ends of the first leaf spring body 12 and the second leaf spring body 13 to the connecting portion 10 made of a rigid body, and connecting the so-called Π shape in a side view. is there. The base end of the first leaf spring body 12 is brazed and fixed to one side surface of the main strut portion 6a, while the base end of the second leaf spring body 13 is also brazed to the mover 14 attached to the front end of the piezoelectric element 5. It sticks. The extending direction of the first leaf spring body 12 and the second leaf spring body 13 is parallel to the extending direction of the print wire 7 and is opposite to the extending direction of the print wire 7 from the connecting portion 10. It is something to set.

The lower surface of the movable element 14 and the front surface of the piezoelectric element 5 may be bonded and fixed with an adhesive, or the movable element 14 is pressed against the front surface of the piezoelectric element 5 in a contracted state. It may be configured as follows. In addition, one or a plurality of spacers may be inserted between the mover 14 and the piezoelectric element 5, and in that case, the spacer on the mover 14 side and the spacer on the piezoelectric element 5 side are pressed and contacted. It may be in a state or may be fixed to each other with an adhesive.

As shown in FIG. 2, when the piezoelectric element 5 and the mover 14 move in the arrow y direction by the application of a voltage, the connecting portion 10 at the tip of both the leaf spring bodies 12, 13 rotates in the arrow A direction. It is displaced (see the chain double-dashed line in FIG. 2). The displacement amount is enlarged by the arm 8 and the printing wire 7 is driven so as to protrude from the nose portion 3. When the piezoelectric element 5 is discharged, the piezoelectric element 5 contracts in the direction of the arrow y ', so that the tip end side of the arm 8 is retracted by the restoring force of the elastic deformation of the two leaf spring bodies 12, 13. The stopper 15 made of resin or the like attached to the arm 8 comes into contact with the support-side stopper 16 attached to the sub strut portion 6b, and the arm 8 repeats vibration and is damped and stopped.

Reference numeral 23 shown in FIG. 2 denotes a four-node link mechanism member (link plate) which is disposed across the other side portion of the mover 14 and the sub strut portion 6b. Reference numeral 23 is made of an elastic material such as a spring plate, and has two vertical link portions parallel to the expansion and contraction direction of the piezoelectric element 5 and a pair of horizontal link portions provided with elastically deformable hinge portions between the two vertical link portions. In order to prepare a so-called 4-section parallel link,
The wide side plate portions 23a, 23a are provided with a cutout hole 24 having a substantially H shape in a side view. On the outer diameter side of the cutout hole 24,
The left and right wide side plate portions 23a, 23a are fixed to the fixed portions 25 on the front and back side surfaces of the auxiliary column portion 6b and the front and back side surfaces of the mover 14 by welding (resistance welding, spot welding), brazing, or the like. When the piezoelectric element 5 expands and contracts when a voltage is applied, the left and right wide side plate portions 23a, 23 of the four-bar linkage mechanism member 23 are formed.
a is elastically deformed into a parallelogram shape in a side view so that the movable element 14 can be moved in parallel along the longitudinal direction of the position-fixed sub-column portion 6b. In other words, the mover 14 is configured to move linearly along the longitudinal direction of the piezoelectric element 5.

The guide plate portions 23b, 23b formed integrally with or separately from the four-bar linkage member 23 are fixed to the main strut portion 6a and the sub strut portion 6b by spot welding or the like to form the sub strut. The deformation of the portion 6b is suppressed. Reference numeral 30 is an annular connecting support made of a metal plate for connecting the front ends of the main support columns 6a in the supporting frames 6 of all the printing units 9, and as shown in FIGS. Support 3
0 has a plurality of mounting holes 31 formed along its circumferential direction, and the heads 3 of the screws 32 are provided in front of each mounting hole 31.
A sunken seat portion 33 into which 2a is fitted is formed. On the other hand, the main support column 6a of each support frame 6 is provided with a mounting recess 35 for non-rotatably fitting the square nut 34 that is screwed into the screw 32, and communicates with the recess 35. An open vertical groove 36 is provided on the side surface and the front end of the column 6a. With this configuration, the attachment hole 3 of the connection support 30
The screw 32 inserted into 31 is threadedly fastened to the square nut 34 fitted through the vertical groove 36 and fitted into the mounting recess 35 in advance to perform positioning and assembly.

On the front surface (flat surface) of the connecting support 30, at least three vibration isolating members 37 such as flat vibration isolating rubber and felt are stretched, and the vibration isolating members 37 are attached to the head body. It is fixed by the screw 38 while being in contact with the back surface of the first substrate 1b. With this configuration,
Since the vibration of each support frame 6 due to the driving of the piezoelectric element 5 is not directly transmitted to the substrate 1b of the head body 1, it is possible to eliminate the noise when the print head is driven.

The mounting hole 31 and the sink seat 33 in the connecting support 30 are formed so as to communicate with the inner peripheral surface (or outer peripheral surface) of the connecting support as shown by the alternate long and short dash line in FIG. If the square nut 34 is screwed onto the screw 32 in advance, the head 32a of the screw 32 is sunk and the seat portion 33 is sunk.
Since the shaft portion of the screw 32 can be inserted into the mounting hole 31 and the vertical groove 36 from the direction perpendicular to the longitudinal axis of the screw 32,
The connection work between the connection support 30 and the support frame 6 becomes extremely simple.

Reference numeral 39 is a reinforcing connecting member having a substantially annular shape in plan view,
The reinforcing connecting body 39 is straddled over the rear surface (rear surface) of the rear end portion 6c of the support frame 6 in all the printing units, and the reinforcing connecting body 39 and each of the rear end portions 6c are fixed by an adhesive.
Or brazing, electron beam welding, laser (micro)
Fix by welding. Then, the cover 2 which is separate from the reinforcing connection body 39 is attached to the side surface of the substrate 1b of the head body 1 or the like via a spacer such as rubber. Reference numeral 40 is a terminal for energizing the piezoelectric element 14 in each printing unit,
The lead wire 41 of each terminal 40 is exposed from the mounting hole 42 formed in the bottom plate 2 a of the cover 2 and then the mounting hole 42.
Is filled with a sealing material 43 such as a synthetic resin. This sealing material 43
May serve also as a silicone rubber having a high heat dissipation property, which is filled inside the head for heat dissipation. Also, the bottom plate 2 of the cover 2
A control plate 44 made of an electrically insulating synthetic resin with a conical guide hole for easily guiding the lead wire 41, which is curved and the position of which is apt to be displaced, is attached to the outer surface of a, and a printed wiring is attached to this. The plate 45 is stretched.

According to this structure, when the piezoelectric element 5 is repeatedly driven by the drive signal given to the print head according to the print data, the vibration from the motion transmission mechanism 9 or the like is damped via the prevention member 37. Since it is transmitted to the substrate 1b of the head body in this state, no noise is generated outside.
Further, since the print unit 4 is mounted on the connection support 30 in advance, it is possible to attach the print unit 4 to the head main body 1 in a state in which the positional relationships such as the intervals of the print units 4 are accurately adjusted. Will be easier.

The supporting frames 6 of the plurality of printing units 4 are connected to each other via the front connecting support 30 and the rear reinforcing connecting body 39 to form an integrated structure, and the rigidity is significantly improved as a whole. To do. Therefore, for example, even when the piezoelectric elements 5 at several positions of the 24 printing units 4 arranged in a diamond shape with the tip of the printing wire 7 being driven as described above, the respective support frames 6 are remarkably large. Deformation (expansion and contraction) becomes difficult, and eventually the impact force of the printing wire during printing drive is not insufficient.

[0019]

As described above, according to the present invention, the piezoelectric element that expands and contracts when a voltage is applied, and the motion transmitting mechanism that transmits the expansion and contraction of the piezoelectric element to the print wire that stamps the print medium. And a plurality of printing units each including a rear end portion of the piezoelectric element and a support frame that supports the motion transmitting mechanism and are arranged in the longitudinal direction along the side of the piezoelectric element, and the front end of each printing wire. In a dot impact print head device, which is disposed on the back surface side of the head main body so as to project and retract from the head main body, the front portions of the support frames of the plurality of printing units are fixed to the connection support, and the connection support In this configuration, in which a vibration-proof member is inserted between the head main body and the head main body that fixes it, the vibration due to the movement of the motion transmission mechanism at the time of driving the piezoelectric element in each printing unit is not supported. Without being transferred directly to the head body via the frame, the effect of preventing a state that spread as noise outside of the print head unit.

Further, by temporarily fixing the front ends of the plurality of support frames to the connecting support body and then mounting them on the head main body,
Since the position of the supporting frame can be set accurately, when a large number of printing units are directly attached to the head main body, it is difficult to set them so that the arrangement intervals of the respective printing units do not become out of order. The effect is that it can be eliminated.

[Brief description of drawings]

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

FIG. 2 is an enlarged side view of a main part.

3 is a sectional view taken along the line III-III of FIG.

FIG. 4 is a sectional view taken along the line IV-IV in FIG.

FIG. 5 is a perspective view of a connection support body.

[Explanation of symbols]

 1 Head Main Body 3 Nose Section 5 Piezoelectric Element 6 Support Frame 6a Main Support Section 6b Sub Support Section 6c Connecting Section 7 Printing Wire 8 Arm 9 Motion Transmission Mechanism 12 First Leaf Spring Body 13 Second Leaf Spring Body 14 Mover 15 Arm Side Stopper 16 Supporting side stopper 23 Four-bar linkage mechanism member 30 Connection support body 31 Mounting hole 32, 38 Screw 34 Square nut 35 Recess 36 Vertical groove 37 Anti-vibration member 39 Reinforced connection body

Claims (1)

[Claims] 1. A piezoelectric element which expands and contracts when a voltage is applied,
A motion transmitting mechanism for transmitting the expansion and contraction of the piezoelectric element to a print wire for stamping on a print medium, and a motion transmitting mechanism for the rear end portion of the piezoelectric element which is arranged along the side of the piezoelectric element in the longitudinal direction thereof. In a dot impact print head device comprising a plurality of printing units consisting of a support frame that supports the mechanism, the print wires being arranged on the back surface side of the head body so that the front ends of the respective print wires project and retract forward from the head body, A dot impact print head characterized in that the front portions of the support frames of the plurality of printing units are fixed to a connection support, and a vibration-proof member is inserted between the connection support and a head main body fixing the connection support. apparatus.