JPH058136Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an ultrasonic image recording head used for printing and image recording.

(Problems to be solved by conventional techniques and ideas) Conventional ultrasonic recording methods basically transmit ultrasonic energy to a recording medium that is in close contact with an ink layer. The generated heat generates an ink meniscus, which is transferred to a recording medium. At this time, in order to record more effectively, the ultrasonic energy is concentrated. That is, an acoustic horn is provided between the ultrasonic generating element and the wire. Considering the size of the dots to be recorded, the diameter of the wire is quite thin, about Φ0.3 mm at most.

The method of fixing the wire to the horn is to make a hole of about Φ0.3mm in the center of the output end face of the horn, embed one end of the wire there, and braze or laser weld the base, or fix it to the desired thickness. It was carved out of block material. However, for the following reasons, mechanical damage often occurred in both methods when actually driven. First, in many cases, the machining method causes the material to become brittle due to the heat generated during processing. In addition, in brazing and laser welding methods, the size of the recording device is
Alternatively, considering that a wavelength that is an integral multiple of 1/2 wavelength is placed on the wire portion, the length of the wire is at least about 5 mm, which is sufficiently long compared to the diameter. Therefore, a force greater than the welding strength is applied. The same applies to the case of brazing.

However, if the pores with a diameter of 0.3 mm are made deep (embedded to a length close to the length of the exposed part of the wire), it may be possible to achieve a relatively strong fixing method. It is difficult to create fine pores several millimeters wide.

The purpose of the present invention is to provide an ultrasonic recording head that avoids the problems of conventional manufacturing technology, can be manufactured relatively easily, and has a structure that allows the wire to be fixed to the acoustic horn with sufficient strength. It's about doing.

(Means for Solving the Problems) The present invention has a basic configuration consisting of an ultrasonic energy generating element, an acoustic horn that concentrates the ultrasonic energy generated from the element, and a wire that transmits the energy to a recording medium. The wire is fixed by being embedded in a groove provided on the side of the acoustic horn, and the length of the acoustic horn and wire is half the wavelength at resonance. This is an ultrasonic image recording head.

(Function) As shown in Figure 1, the step horn has a structure in which a groove is cut on the side surface and a wire is embedded in it, and the length l' is an integral multiple of the 1/2 wavelength of the transmitted ultrasonic wave. and l is close to l'. By adopting this structure, it is easier to manufacture and has sufficient wire fixing strength for practical use than the conventional method of drilling a small hole in the center of the end face of the horn and embedding the wire or cutting it out. can get.

The printing performance is comparable to that of a conventional head with wires placed in centrally symmetrical positions, and it leaves a good record.

(Example) Examples according to the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of the ultrasonic image recording device according to the present invention. In the figure, 4 is a laminate of, for example, lead silconate-based or niobic acid-based piezoelectric ceramics and an electrode layer. This is from 100KHz to several MHz
vibrate at a certain resonant frequency. Dimensions are 5mm x 5
mm and the height will be around 9mm. However, the ceramic layer
The thickness is preferably about 100 μm, and the number of laminated layers and the height of the laminated body are adjusted depending on the desired resonance frequency.

Further, 5 is a two-stage step horn. Titanium chromium alloy is used, and the cross-sectional area of the first step horn is changed from 19.6 mm ² to 39.3 mm ² , and the cross-sectional area of the second step horn is changed from 3.14 mm ² to 0.62 mm ² . In each horn the step is located at a length of 1/4 of the transmitted ultrasound wavelength λ, and in each horn the step is located at a length of 1/4 of the transmitted ultrasound wavelength λ
It was designed to have a length of . This two-stage horn magnifies the displacement generated in the piezoelectric ceramic 4 by 25 times.

The heat conductive layer 6 in the ink holder 9 is a good heat conductive layer with low volume resistivity, and is in close contact with the highly heat insulating ink layer 7. The high heat insulating ink layer 7 has a high volume resistivity, and the ink used therein does not reduce the volume resistivity of the high heat insulating ink layer 7 and has a low viscosity enough to be transferred to a recording medium at about several tens of degrees Celsius. There is no particular restriction as long as the viscosity decreases to a level that allows sufficient transfer at a temperature of more than 100 degrees Celsius. The recording medium 8 is not particularly limited, such as a plain paper OHP sheet.

As shown in Figure 2, how to attach the wire to an ultrasonic image recording device that basically has the above configuration, cut a groove with the same diameter as the wire on the side of the second stage horn, and embed the wire in it. Fix by brazing or other means. At this time, the length of the wire portion beyond the horn is λ/2, and the length of the groove starts from a point after the step, so that sufficient fixing strength can be achieved.

(Effects of the Invention) As described above, the present invention simplifies the manufacturing process of the ultrasonic image recording head and reduces costs.

In addition, in this invention, the connection part between the ultrasonic energy generating element, acoustic horn, and wire becomes a node of vibration and no stress is applied, so the reliability of the connection part is high.
In addition, the amplitude of vibration is expanded in each part, that is, each part becomes a component of the resonant system of the wire, and the amplitude of the ultrasonic wave is expanded including the wire, so that vibration energy can be efficiently transmitted to the ink layer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the basic structure of an ultrasonic image recording head according to the present invention. FIG. 2 is a sectional view of an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Ultrasonic energy generating element, 2... Wire, 3... Horn, 4... Piezoelectric laminated ceramic element, 5... Two-stage step horn.

Claims (1)

[Scope of utility model registration request] In an ultrasonic image recording head consisting of an ultrasonic energy generating element, an acoustic horn that concentrates the ultrasonic energy generated from the element, and a wire that transmits the energy to a recording medium, the wire is provided on the side of the acoustic horn. 1. An ultrasonic image recording head, which is embedded and fixed in a groove, and furthermore, the length of the acoustic horn and wire is 1/2 the length of the wavelength at resonance.