JPH0442192B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to impact print heads, particularly impact print heads used in dot impact printers.

Conventionally, there is an impact print head that performs a printing operation by utilizing dimensional distortion caused by the piezoelectric transverse effect of piezoelectric or electrostrictive ceramics.

Figures 1a and 1b are perspective and side views, respectively, of a conventional impact print head. The printing head shown in FIG. 1A has a plurality of printing units 1 arranged and attached to one end of a head base 2, and a pin 11 fixed to an end of each printing unit 1 is provided at the other end of the mounting member 2. The pins are configured to be aligned through guide holes of the pin alignment member 21. Each printing unit 1 includes a conductive electrode plate 5, as shown in FIG.
Piezoelectric plates 41 and 42 are fixed to both sides of 0, and conductive electrode plates 51 are attached to both outer surfaces of the piezoelectric plates 41 and 42, respectively.
A pin 11 for printing dots is attached and fixed to one end of a piezoelectric vibrator to which a pin 11 and a dot 52 are fixed. Electrode plates 51 and 52 are connected to one of a pair of conductive wires 6 via metal attachment member 2, and electrode plate 50 is connected to the other conductive wire 6. The piezoelectric plates 41 and 42 have been polarized in advance, and when a driving voltage is applied between the electrode plates 51 and 52 and the electrode plate 50 via the conductive wire 6, the piezoelectric plates 41 and 42 are polarized due to the piezoelectric transverse effect. The piezoelectric plate 42 contracts and causes a strain in the direction of the broken line arrow A, and the piezoelectric plate 42 expands and causes a strain in the direction of the broken line arrow B. Along with this, the piezoelectric vibrator is deflected, and the pin 11 moves in the direction of the broken line arrow C, thereby performing a printing operation of striking a dot on the printing surface.

Conventional impact print heads such as those described above have disadvantages of large size and high power consumption. That is, the printing unit 1 used in the conventional impact printing head is
Printing is performed by generating dimensional distortion in the piezoelectric body using the piezoelectric transverse effect, but the resulting distortion is smaller in the piezoelectric transverse effect than in the case of the piezoelectric longitudinal effect (about 1/3 times the Poisson's ratio). times), so in order to store the specified mechanical energy, it is necessary to have a large volume (the square of Poisson's number, that is, approximately 9 times the volume), and since the electromechanical coupling coefficient is small, in order to obtain the specified strain, Requires large driving power (approximately 5 times as much power). In a conventional impact printing head equipped with a plurality of printing units 1 that utilize such a piezoelectric transverse effect, each printing unit 1 is large in size as described above, and each printing unit 1 does not allow printing by other printing units during printing operation. The units 1 must be arranged with a sufficient distance from each other so that they do not come into contact with each other, and an increase in the size of the print head is unavoidable.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide an impact print head that is compact and consumes less power.

The print head of the present invention includes a piezoelectric body that generates dimensional strain due to a piezoelectric longitudinal effect, a mounting member that supports one end of the piezoelectric body, and a mounting member that magnifies the dimensional strain of the piezoelectric body to generate and transmit angular displacement. A plurality of plates each having a displacement transmitting section having a plurality of movable members and a linear printing member that is attached to a predetermined location of the displacement transmitting section and moves in a predetermined direction in accordance with the angular displacement. a printing unit, at least one alignment member provided with a plurality of guide holes through which the tip end of each of the printing members of the printing unit can slide, and a plurality of the printing members arranged on substantially the same plane with respect to each other with a predetermined accuracy. A plurality of the printing units are arranged in a radial straight line, and each of the printing units is arranged in a stacked manner, one by one, with the selected part of the character member passing through each of the guide holes, and one by one facing the opposite direction alternately on the board surface. and a head stand having a unit holding member that supports the mounting member at a predetermined location.

Next, the present invention will be explained in detail with reference to the drawings.

FIG. 2 and FIGS. 3a and 3b are a perspective view, a top view, and a side view, respectively, showing an embodiment of the present invention. FIG. 2 shows an example of the configuration of the printing unit used in this embodiment. Electrodes 5 are provided on both sides of the piezoelectric body 4, and a driving voltage is applied to each electrode 5 via a conductive wire 6. The lower end of the piezoelectric body 4 is fixed to the mounting member 3, and the upper end of the piezoelectric body 4 is connected to the lower ends of the first and second movable members 15 and 17 via the first and second coupling members 8 and 10, respectively. It is connected. 1st and 2nd
The lower ends of movable members 15 and 17 of
It is connected to the mounting member 3 via 2 and 14. The mounting member 3 is integrally formed of metal with the first to fourth coupling members 8, 10, 12, and 14 and the first and second movable members 15 and 17, and has mounting holes 7 at predetermined locations. It is provided. First and second movable members 15 and 17
One ends of fifth and sixth coupling members 16 and 18 of metal plates are respectively fixed to the upper ends of the
The other ends of the fifth and sixth coupling members 16 and 18 are each fixed to a predetermined location of a third movable member 20 made of metal. A pin 22 made of a round metal rod is attached and fixed to the tip of the third movable member 20.
Inside the piezoelectric body 4, a plurality of electrode plates (not shown) having surfaces perpendicular to the length direction of the piezoelectric body 4 are provided at a predetermined interval. They are alternately connected to one of the electrodes 5 on both sides. Therefore, when a driving voltage is applied to the electrode 5, an electric field is generated between the electrode plates in the piezoelectric body 4 in a direction substantially parallel to the length direction of the piezoelectric body 4, and the piezoelectric body 4 is extended in length due to the piezoelectric longitudinal effect. Stretch in the direction. The dimensional distortion caused by the elongation of the piezoelectric body 4 is transmitted to the first and second movable members 15 and 17 via the first and second coupling members 8 and 10, respectively.
Since the first and second movable members 15 and 17 are supported by the mounting member 3 via the third and fourth coupling members 12 and 14, respectively, when the piezoelectric body 4 receives dimensional strain, the first The upper ends of the second movable members 15 and 17 undergo angular displacement in the directions of dashed arrows D and E, respectively. When these two angular displacements are transmitted to the third movable member 20 via the fifth and sixth coupling members 16 and 18, a couple acts on the third movable member 20, which is attached to the tip. The pin 22 moves in the direction of the broken line arrow F to perform a printing operation. As explained above,
First to third movable members 15, 17 and 20
It operates as a lever, sequentially magnifies and transmits the dimensional strain generated by the piezoelectric body 4, and gives the pin 22 a displacement with an amplitude necessary for printing operation. By utilizing the dimensional distortion of the piezoelectric body 4 due to the piezoelectric longitudinal effect, it is possible to realize a printing unit that is smaller and consumes less power than printing units used in conventional print heads.

3a and 3b show an impact printing head using the printing unit shown in FIG. A first pin alignment member 33 is provided at one end of the head stand 30.
A second pin alignment member 34 is provided at a predetermined distance from the second pin alignment member 34 to prevent unnecessary vibration of the pin 22 during printing operation. The other end of the head stand 30 is provided with a columnar mount 31 having a plurality of grooves 32 for mounting a printing unit. The head stand 30 is the first
The second pin alignment members 33 and 34 and the mounting base 31 are integrally formed of metal or plastic, and each of the first and second pin alignment members 33 and 34 receives one pin 22 of the printing unit. As many guide holes as the pins 22 are provided so as to be slidable therethrough. A predetermined portion of one end side of the mounting member 3 of the printing unit is fitted into the groove 32 of the mounting base 31 to hold the printing unit. The plurality of printing units are sequentially arranged one on top of the other at predetermined intervals such that the third movable members 20 are alternately located on the opposite side, and the pins 22 of each printing unit are connected to the first and second movable members 20, respectively. The pins are aligned through the guide holes of the pin alignment members 33 and 34, and are arranged radially on substantially the same plane. Insert a long and thin bolt 24 into the mounting hole 7 of the mounting member 3 of the printing unit shown in FIG. 2, tighten one end with a nut, and attach the printing unit to the head stand 30.
It is held in When a driving voltage is applied to the piezoelectric body 4 of each printing unit, the dimensional distortion caused in the piezoelectric body 4 is magnified by the first to third movable members 15, 17, and 20, as explained in FIG. The displacement is transmitted to the pin 22, and the pin 22 moves in the direction of the dashed arrow F to perform a printing operation.

In the print head of this embodiment, since the piezoelectric longitudinal effect type piezoelectric body 4 is used in the printing unit, the printing unit is smaller and consumes less power than the conventional printing unit. As shown in Fig. 3b, since the printing units are arranged one on top of the other in reverse order, the area occupied by the printing unit group can be reduced, and the conductors 6 of the printing units adjacent above and below can be welded. Since the raised parts and the positions of the first to third movable members 15, 17, and 20 can be shifted, there is no need to take up extra space to prevent mutual contact between the upper and lower parts.
The stacking height of the printing unit group can be minimized,
As a result, the space occupied by the printing unit group can be made smaller than before. Note that FIGS. 2 and 3a and 3b only show one example of the configuration, and the configuration of the present invention is not limited thereto. It is clear that in the printing unit of FIG. 2, the same operation can be achieved by changing the shape and interconnection of the levers that magnify and transmit the dimensional strain of the piezoelectric body 4. In the printing heads shown in Figs. 3a and 3b, the mounting base 31 is not provided on the head stand 30, and instead, a spacer of a predetermined thickness is inserted between each printing unit to mount it, or unnecessary vibration occurs during printing operation. It is easy to change each detail as appropriate, such as determining the shape and dimensions of the pin 22 so as to avoid the second pin aligning member 34, and in that case, the same effect as that of this embodiment can be obtained. is clear.

As is clear from the above description, the present invention has the effect of realizing an impact printing head that is smaller and consumes less power than conventional ones, and is particularly suitable for use in dot impact printers. can be achieved.

[Brief explanation of the drawing]

1A and 1B are a perspective view and a side view of a conventional impact printing head, and FIGS. 2A and 3B are a perspective view and a top view and a side view of an embodiment of the present invention. 3... Mounting member, 4... Piezoelectric body, 5... Electrode,
6...Conducting wire, 8...First coupling member, 10...Second coupling member, 12...Third coupling member, 14...
...Fourth coupling member, 15...First movable member, 1
6...Fifth coupling member, 17...Second movable member, 18...Sixth coupling member, 20...Third movable member, 22...Pin, 30...Head stand, 31
...Mounting base, 33...First pin alignment member, 34
...Second pin alignment member.

Claims (1)

[Scope of Claims] 1. A piezoelectric body that generates dimensional strain due to the piezoelectric longitudinal effect, a mounting member that supports one end of the piezoelectric body, and a mounting member that magnifies the dimensional strain of the piezoelectric body to generate and transmit angular displacement. A plurality of plates each having a displacement transmitting section having a plurality of movable members and a linear printing member that is attached to a predetermined location of the displacement transmitting section and moves in a predetermined direction in accordance with the angular displacement. a printing unit; at least one alignment member provided with a plurality of guide holes through which the tips of the printing members can slide; and a plurality of the printing members arranged at a predetermined angle with respect to each other on substantially the same plane; A plurality of the printing units are arranged in a radial line, and each of the printing units is stacked one on top of the other, with the tip of each printing member passing through each of the guide holes, one by one, alternately oriented in opposite directions on the plate surface. 1. An impact printing head comprising a head stand having a unit holding member that supports the member at a predetermined location.