JPS62248658A - Wire dot recording head - Google Patents

Abstract

PURPOSE:To shorten the period of time during which a vibration continues and contrive a higher recording speed, by driving a wire toward a recording medium by an electro- mechanical energy converting element such as a piezoelectric element, and attracting a leaf spring formed of a ferromagnetic material and connected to the wire by an electromagnet to restrict the wire to an initial position. CONSTITUTION:When a pulse P1 of a driving signal S1 is applied and a piezoelectric element 1 is expanded to strike a flight hammer 6, a wire 5 collides against a paper 9 against the force of a leaf spring 4, thereby recording a dot. After the collision, the wire 5 is returned by a repulsive force of a platen 10 and the force of the spring 4. An exciting signal S2 is applied to excite a magnetic coil 11 for a predetermined period of time from a moment immediately after the time A of the collision, and a magnetic flux passes through a mount member 3 and the leaf spring 4, resulting in that the spring 4 is attracted onto the member 3 by a magnetic force. Accordingly, the returning speed of the wire 5 is enhanced. When the wire 5 is returned to an initial position and the hammer 6 collides against the piezoelectric element 1, the leaf spring 4 also comes into contact with an end face 3b of the mount member 3, and is attracted onto the end face 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a wire dot recording head, and more particularly to a wire dot recording head in which a wire that strikes a recording medium is driven by an electric/mechanical energy conversion element such as a piezoelectric element. .

[Prior Art] A known wire dot recording head of this type performs a recording operation by driving a wire by utilizing dimensional distortion caused by the piezoelectric effect of a piezoelectric element. FIG. 4 shows an example of the structure of a recording unit that drives each wire in such a conventional wire dot recording head.

In FIG. 4, the piezoelectric element 1, which is the drive source for the recording operation, is constructed by laminating a large number of piezoelectric pieces, and connecting the electrodes on the front and back sides of each piece to an external electrode 2 by drawing out the same polarity from every other piece. , an L-shaped attachment is fixed to one end of the member 3. For installation, the plate spring 4 is attached to the other end of the member 3 using a screw 1.
2, and a wire 5 for striking the recording medium and a flight hammer 6, which is a weight for increasing the inertial energy of the wire 5, are fixed on the front and back sides at the tip thereof.

The flight hammer 6 is pressed against the piezoelectric element 1 by the leaf spring 4. Moreover, the tip of the wire 5 is
A sheet of paper 9 as a recording medium is placed opposite to a platen 10 of a recording table with a certain gap 7 in between. An ink ribbon 8 is stretched between the wire 59 and the paper 9.

With this structure, when a driving voltage is applied to the piezoelectric element 1 through the external electrode 2 during recording, the piezoelectric element 1 instantaneously stretches (approximately 1 #Ls) due to dimensional distortion due to the so-called laminated piezoelectric longitudinal effect, causing the flight hammer 6 to elongate. to hit. Due to this impact force, the flight hammer 6 flies to the right in the figure together with the wire 5 against the spring force of the leaf spring 4, and the wire 5 collides with the paper 9 via the ink ribbon 8, and due to the impact force, the ink ribbon 8
The ink is transferred onto the paper 9, and dots are recorded.

Thereafter, the wire 5 returns in the opposite direction due to the repulsive force of the platen lO and the spring force of the leaf spring 4, and returns to the initial position n shown in FIG. 4, that is, the position where the flight hammer 6 is pressed against the piezoelectric element l. This completes the dot recording operation.

[Problems to be Solved by the Invention] However, in the above structure, when the wire 5 returns to the initial position together with the flight hammer 6 after colliding with the paper 9, the flight hammer 6 collides with the piezoelectric element 1, and the wire 5, it bounces and continues damped vibration for a while. The duration is significantly longer than the time from the start of driving the piezoelectric element 1 until the flight hammer 6 returns and collides with the piezoelectric element 1.

For this reason, the cycle of repetitive driving of the wire 5 becomes significantly long, and the frequency of repetitive driving remains at several 100 Hz, which poses a problem in that it is difficult to increase the speed of recording further. Note that increasing the spring force of the leaf spring 4 will shorten the duration of the vibration, but since the impact force for recording by the piezoelectric element 1 will become relatively small, there is a limit to increasing the spring force. There is.

[Means for Solving the Problems] In order to solve the above-mentioned problems, a wire dot recording head according to the present invention includes an electric/mechanical energy conversion element that drives a recording medium striking wire toward the recording medium; The wire is combined with the wire as a medium material! 1113
Dot recording is performed by a recording unit having a leaf spring made of a ferromagnetic material that returns the wire to its initial position, and an electromagnetic means that attracts the leaf spring by magnetic force to an initial position of the leaf spring corresponding to the initial position of the wire when the wire returns. The configuration was adopted.

[Function] According to such a configuration, when the wire returns to the initial position after being hit by the medium, the leaf spring is attracted by the electromagnetic means to the initial position of the leaf spring corresponding to the initial position of the wire.
It is possible to suppress the wire from directly or indirectly contacting a member that regulates its initial position and bounce and vibrate, thereby shortening the duration of the vibration.

[Example] Hereinafter, details of embodiments of the present invention will be described.

FIG. 1 shows the structure of a recording unit that drives each wire in the wire dot recording head according to this embodiment. In the figure, members corresponding to those of the conventional example shown in FIG. 4 are given the same reference numerals. It's a dike.

In the structure shown in FIG. 1, the piezoelectric element l is similar to that of the prior art example described above, but the mounting of the piezoelectric element 3 in which it is fixed is significantly different from that of the conventional example.

That is, the mounting member 3 is entirely made of ferromagnetic material,
The cross section is formed into a substantially square shape, and a piezoelectric element 1 is fixed to the side surface of an end portion 3a of one side connecting two parallel sides, which protrudes upward in the figure, in parallel with the two sides. And above 2
An electromagnetic coil 11 is wound around the middle part of one side connecting the sides. In other words, the installation is 17 with member 3 and electromagnetic coil 11.
It is composed of 71 stones, and the attached member 3 serves as the iron core and yoke of the electromagnet.

In addition, the base end portion of the leaf spring 4 is fixed to the end surface 3C of one lower side of the member 3 with a screw 12. The leaf spring 4 is made of a ferromagnetic material such as steel, and has a wire 5 and a flight hammer 6 on the front and back sides of the tip, as in the conventional example.
are combined.

The flight hammer 6 is moved to the piezoelectric element 1 by the spring force of the leaf spring 4.
The position of the wire 4 in this state is its initial position.

Then, the leaf spring 4 is attached with the wire 5 held at the initial position and comes into contact with the upper end surface 3b of the two parallel sides of the member 3, and the position of the leaf spring 4 in this state corresponds to the initial position of the wire 5. This is the initial position of the plate spring 4, and in this state, the attached member 3 and the plate spring 4 form the magnetic closed circuit of the electromagnet described above.

Note that the tip of the wire 4 is, of course, placed opposite to the platen 10 with a predetermined gap therebetween, with the ink ribbon 8 and paper 9 interposed therebetween.

The recording head of this embodiment is constructed by assembling a predetermined plurality of recording units having the above structure.

In this case, the "W!" and "a" coils 11 of each unit are connected in series with each other as shown in FIG.
The driver 13 is connected between a power source that applies an excitation voltage VH and a 7-segment via a Darlington connection of two transistors TI and T2. Then, an excitation signal S2 is outputted from a control section (not shown) of a printer in which this recording head is mounted on the base of the transistor T1, so that each coil 11 is simultaneously and commonly energized and excited.

Next, to explain the operation of the recording head of this embodiment, each recording unit receives a drive signal S of the piezoelectric element 1 as shown in FIG.
1 and the above-mentioned excitation signal S2 of the electromagnetic coil 11, the electromagnetic coil 11 is driven as follows.

First, in a standby state before the drive signal S1 is applied, the excitation signal S2 is not applied, the electromagnetic coil 11 is not excited, and the flight hammer 6 is pressed against the piezoelectric element 1 by the spring force of the leaf spring 4, and the wire 5 is held at the initial position shown in FIG.

Next, at the time of recording, as shown in FIG.
A pulse PL is applied, whereby the piezoelectric element 1 expands and contracts and hits the flight hammer 6. The flight hammer 6 flies together with the wire 5 to the right in FIG. 1 against the spring force of the leaf spring 4, and at the point indicated by the symbol A in FIG. collided with paper 9,
Dots are recorded with that batting force.

After the collision, the wire 5 returns to the left in FIG. 1 due to the repulsive force of the platen lO and the spring force of the leaf spring 4. At this time, the third
As shown in the figure, the excitation signal S2 is applied for a predetermined period of time immediately after the collision point A to excite the electromagnetic coil 11, and the magnetic flux flows through the attachment member 3 and the leaf spring 4, and the magnetic force causes the leaf spring 4 to become attached. It is attracted to member 3. This increases the return speed of the leaf spring 4, that is, the return speed of the wire 5.

When the wire 5 returns to the initial position shown in FIG. 1 and the flight hammer 6 collides with the piezoelectric element 1, the plate spring 4 also comes into contact with the end surface 3b of the attached member 3 and is attracted thereto.

At this time, during installation, there is no air gap between the member 3° and the leaf spring 4, and the aforementioned magnetic closed circuit is formed, and the attractive force against the leaf spring 4 is maximized.

The flight hammer 6 that collides with the piezoelectric element 1 bounces and vibrates together with the wire 5, but the vibration is minimized by the above-mentioned suction force, and the duration of the vibration is minimized.

Therefore, according to this embodiment, the next pulse P2 of the excitation signal S1 shown in FIG. 3 can be quickly applied.

The repetitive drive period of the wire 5 can be significantly shortened, and the recording speed can be significantly improved.

Further, according to this embodiment, the electromagnetic coil 1 of each recording unit
1 are connected in series and each electromagnetic coil 11 is energized and excited at the same time through a common driver, so the number of elements such as transistors that constitute the driver 13 can be minimized, and power consumption can also be minimized. can do.

[Effects] As is clear from the above description, the wire dot recording head of the present invention includes an electric/mechanical energy conversion element that drives a recording medium striking wire toward the recording medium;
a leaf spring made of a ferromagnetic material that is coupled to the wire and causes the wire to return to its initial position after being hit by a medium; and electromagnetic means that magnetically attracts the leaf spring to an initial position of the leaf spring corresponding to the initial position of the wire upon return. Since we have adopted a configuration in which dot recording is performed using a recording unit with This can significantly improve recording speed.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing the structure of a recording unit constituting a wire dot recording head according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of the excitation circuit of the electromagnetic coil in FIG. 1 in the embodiment head, FIG. 3 is a timing chart of the drive signal of the piezoelectric element and the excitation signal of the electromagnetic coil in FIG. 1,
FIG. 4 is a sectional view showing the structure of a recording unit of a conventional wire dot recording head. ■...Piezoelectric element 3...Mounting member 4...
・Plate spring 5...Wire 6...Flight hammer 8...Ink ribbon 9...Paper
10...Platen 11...Electromagnetic coil 13.
・・Driver n days

Claims (1)

[Scope of Claims] 1) An electrical/mechanical energy conversion element that drives a recording medium striking wire toward the recording medium, and a ferromagnetic material that is coupled to the wire and returns the wire to its initial position after striking the medium. A wire dot recording head, characterized in that dot recording is performed by a recording unit having a plate spring and an electromagnetic means that attracts the plate spring by magnetic force to an initial position of the plate spring corresponding to the initial position of the wire when the wire returns. 2) The wire dot recording head according to claim 1, wherein the leaf spring forms a magnetic closed circuit with the iron core and yoke of the electromagnet means in the attracted state. 3) A plurality of sets of the recording units are provided, and the electromagnetic coils of the electromagnetic means of each unit are connected in series, and each electromagnetic coil is energized simultaneously. The wire dot recording head according to item 2. 4) A patent claim characterized in that the electromagnetic coil of the electromagnet means is energized for a predetermined period of time immediately after the wire driven by the energy conversion element hits the recording medium to cause attraction by the electromagnet means. The wire dot recording head according to any one of the ranges 1 to 3.