JPS62275764A - Dot printer - Google Patents

Abstract

PURPOSE:To enable a cylindrical body to vibrate due to supersonic wave so that printing density may be secured even if printing pressure is at low level by connecting a high-frequency power supply to an electrode of a cylindrical body consisting of complex piezoelectric elements provided on the external periphery of a platen and keeping the high-frequency power supply ON while a printing wire is in contact with a printing medium on the surface of the cylindrical body. CONSTITUTION:A platen 1 is a thin-wall hollow cylinder made of aluminum alloy and made freely rotatable with a cylindrical body 2 consisting of complex piezoelectric elements fixed to the external periphery of the platen through an insulation layer 3. That is, the cylindrical body 2 has piezoelectric ceramic elements 21 of for instance, Pb (Zr, Ti) O3 connected through a resin layer 25. In addition, electrode layers 22, 23 are provided on the internal and external surfaces of the platen respectively, and a protective layer 24 of hard rubber is provided on the external surface of the electrode layer. When a voltage is applied to the electrode layers 22, 23 from, e.g. a 100kHz high-frequency power supply, the piezoelectric ceramic elements 21 vibrate under the effect of supersonic wave in a diametral direction of the cylindrical body 2 transmitting the vibration even to recording paper on the platen 1. If printing wire in a printing head is selectively driven by means of electric signal and the recording paper is pressed via ink ribbon, the recording paper vibrates due to supersonic wave, even through the pressure is at low level. Thus printing density can be kept at the same or higher level as or than that of the conventinoal printer.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention selectively drives a plurality of printing wires disposed facing a cylindrical platen. It is related to dot printers that print.

In particular, the present invention relates to improvements to dot printers that reduce noise generated during printing.

[Conventional technology]

In a conventional printing/recording device, a print head having a plurality of printing wires is provided facing a cylindrical platen, and the plurality of printing wires are selectively driven by an electric signal to print on the platen. Printing is performed by colliding the ink ribbon with a recording paper placed on the ink ribbon.

[Problem that the invention seeks to solve]

In the above-mentioned print recording method, since print density is secured by the kinetic energy generated when the printing wire collides with the platen, there is a problem in that noise is generated during printing. Furthermore, with the recent spread of office automation, the number of installed printing and recording devices has increased, so if a large number of printing devices are operated at the same time, other office work may be adversely affected. Furthermore, since the printing pressure required to ensure printing density is high, wear of the printing wire is accelerated, resulting in a short service life.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems existing in the above-mentioned conventional techniques and to provide a dot printer which is low in noise and has a long printing wire life.

[Means for solving problems]

In order to solve the above problems, in the present invention, a cylindrical platen is rotatably provided.

In the dot printer, one end of a plurality of printing wires is provided to face the platen, and the other end of the printing wire is connected to a drive member of an actuator to selectively drive the printing wire. A cylindrical body made of a composite piezoelectric material is provided on the outer periphery, and a high frequency power source is connected to the electrode of this cylindrical body so that it can be turned ON and OFF at will, at least while the printing wire is in contact with the printing medium on the surface of the cylindrical body. is formed so that the high frequency power source is in an ON state. This technical method was adopted.

[Effect]

With the above configuration, while the printing wire is in contact with the surface of the cylinder, the high-frequency power source is turned on, and the cylinder made of composite piezoelectric material vibrates with ultrasonic vibrations of, for example, 100 KHz, so that printing is possible. Even if the pressure is low, sufficient print density can be ensured.

〔Example〕

FIG. 1 is a cross-sectional view of a main part showing an embodiment of the present invention. In the figure, reference numeral 1 denotes a platen, which is made of a material such as an aluminum alloy and is formed into a thin hollow cylindrical shape and is rotatable. 2 is a cylindrical body made of a composite piezoelectric material,
It is fixed to the outer periphery of the platen 1 via the insulating layer 3. That is, the cylinder 2 is, for example, P b (Z r, T i)
A piezoelectric ceramic element 21 such as No. 03 is connected via a resin layer 25.

Electrode layers 22 and 23 are provided on the inner and outer surfaces, respectively.

Note that 24 is a protective layer 1 made of a material such as hard rubber, and provided on the outer surface of the cylindrical body 2. Next, the electrode layer 22
．． Each of the leads 23 is provided with a lead, and is connected to a high frequency power source (none of which is shown) of, for example, 100 KHz so as to be turned on and off.

With the above configuration, when a voltage is applied to the electrode layers 22 and 23 from the high frequency power source, the piezoelectric ceramic element 21
ultrasonic vibration in the diametrical direction. Therefore, the ultrasonic vibrations are also transmitted to the recording paper (not shown) wrapped or arranged on the platen 1. Since the platen 1 is provided with a print head (not shown) facing the platen 1, the print head (not shown) configured in the same manner as the conventional device is provided, so that by selectively driving the print wire in the print head using an electric signal, the print head (not shown) can be printed via the ink ribbon. By pressing the recording paper, a desired print record can be obtained. In this case, even if the pressure applied to the printing wire is lower than that in the conventional device, the printing density can be made equal to or higher than that in the conventional device by causing the recording paper to vibrate ultrasonically as described above. Can be done. The protective layer 24 provided on the outer surface of the cylindrical body 2 has the effect of protecting the cylindrical body 2, especially the electrode layer 23, from unintentional damage caused by the pressure of the printing wire.

FIG. 2 is a perspective view showing an example of a method for manufacturing the composite piezoelectric body shown in FIG. 1. First, a flat green sheet 2 with a thickness of 1 mm, for example, is made of the piezoelectric ceramic material as described above.
Form a. Next, using a disc-shaped cutter with a width of 1 mm, for example, cut 1l12 pieces vertically and horizontally at intervals of 0.1 to 0.3 mm.
A plurality of b are provided. In this case, the groove 2b leaves a slight uncut portion 2c at the bottom.

Therefore, even if the groove 2b is provided, the green sea h2a has a flat plate shape as a whole. Next, a flexible resin such as an epoxy resin is poured into the groove 2b, and the uncut portion 2c is removed after forming. That is, by cutting the back surface of the green sheet 2a to a thickness corresponding to the uncut portion 2c, or by providing grooves corresponding to the grooves 2b on the back surface and making the grooves communicate with each other, the green sheet 2a can be cut into a thickness corresponding to the uncut portion 2c.
A composite piezoelectric body in which a plurality of piezoelectric ceramic elements 21 are connected is formed by the resin filled in the inside.

Since the composite piezoelectric body thus formed has flexibility, the cylinder 2 can be formed to correspond to the platen 1 shown in FIG. That is, it is formed into a hollow cylindrical shape with an inner diameter corresponding to the outer diameter of the platen 1, and then sintered at a predetermined temperature.

Electrode layers 22 and 23 are provided on the inner and outer circumferential surfaces, a predetermined polarization process is performed, and an electrode layer 24 is provided on the outer circumferential surface.

In this example, the platen is made of aluminum alloy and formed into a hollow cylindrical shape. However, the constituent material is not limited to this, and other metal materials and non-metal materials can be used. It may also have a solid cylindrical shape. Note that, of course, when the platen is formed of an insulating material, the insulating layer between the platen and the cylinder can be omitted. Furthermore, the protective layer provided on the outer peripheral surface of the cylinder is intended to prevent damage to the cylinder due to unintended external force.

For example, if the printing pressure is low or if there is no risk of external force being applied, there is no problem in omitting it.

Further, although an example has been shown in which a flat green sheet is processed as a method for manufacturing a cylindrical body, a method of creating a hollow cylindrical green body from the beginning can also be adopted. Furthermore, the resin and piezoelectric ceramic that form the composite piezoelectric body are not limited to those used in this example, and other materials can be selected, and the frequency of the high-frequency power source to be applied to the composite piezoelectric body can be adjusted to avoid bodily-sensible noise. Therefore, it can be freely selected within the range of 20 to 30 KHz or more. Note that the conventional actuator for driving the printing wire can be used as is, and in relation to the high-frequency power supply, the high-frequency power supply is not activated at least while the printing wire is in contact with the printing medium on the surface of the cylinder. There is no particular limitation as long as it is formed to be in the ON state.

〔Effect of the invention〕

Since the dot printer of the present invention has the structure and operation as described above, it can achieve the following effects.

(1) Print density is not ensured by the kinetic energy generated by the collision of printing wires.

The noise during printing has been significantly reduced from the conventional 80 to 90 phons to less than 50 phons, dramatically improving the office environment including office automation equipment.

(2) Even if the printing pressure is low, the same printing density as before can be obtained, so the life of the printing wire can be more than doubled.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of the present invention. FIG. 2 is a perspective view showing an example of a method for manufacturing a composite piezoelectric body. 1 Nibraten 12: Cylindrical body, 21: Piezoelectric ceramic element. Thatch 1 Figure rate 2 Figure-2C

Claims (1)

[Claims] A platen formed in a cylindrical shape is rotatably provided, one end of a plurality of printing wires is provided facing the platen, and the other end of the printing wire is connected to a driving member of an actuator. In this dot printer, a cylindrical body made of a composite piezoelectric material is provided on the outer periphery of the platen, and a high-frequency power source is connected to the electrode of this cylindrical body so as to be able to be turned on and off freely, so that at least the printing wire can be selectively driven. A dot printer characterized in that the high frequency power source is in an ON state while in contact with a print medium on the surface of the cylinder.