JPH0289647A - Nozzle-less ink-jet recorder - Google Patents

Abstract

PURPOSE:To control the position of the injection of ink on a line by using a liquid having an electroviscous effect as ink while an electrode for applying an electric field to ink is installed at the position of the injection of ink. CONSTITUTION:An electroviscous liquid 32 is employed as ink. When piezoelectric transducers 19a, 19b are supplied with power, vibrations are generated in the direction of thickness, and acoustic energy is generated. The acoustic energy is reflected by a reflecting plate 20 having a radiant surface, and concentrated to a slitty clearance (b). When an electric signal is applied to an electrode terminal 27 and voltage (-100V) is applied to an arbitrary electrode 25 opposed while holding the clearance (b), a low section is formed in the meniscus of ink because the viscosity of ink between the clearance and the arbitrary electrode is increased, and the ink of a section where there is no electric field is injected. Accordingly, ink is given an electroviscous effect, and an electric field is applied to ink at the position of the injection of ink, thus injecting ink at the arbitrary time at the optional position of the line-shaped clearance (a slit) (b).

Description

[Detailed Description of the Invention] [(Summary)] An object of the present invention is to provide a nozzle-less inkjet recording device that can control the ejection position of ink on a line, and to apply acoustic energy to the surface of ink liquid. A nozzle-less inkjet recording device that ejects ink from a liquid surface in a concentrated manner at one point or in a line, using a liquid having an electrorheological effect as the ink, and applying an electric field to the ink at the ink ejection position. It is constructed by providing electrodes.

[Industrial application field]

The present invention relates to a nozzleless inkjet recording device.

Inkjet recording devices are extremely low-noise, capable of high-speed printing, can use inexpensive traditional printing presses, do not require development and fixation, and can record kanji, figures, etc.

Generally, pressure is applied to ink and ink droplets are ejected from a nozzle to record on printing paper. Therefore, clogging may occur due to ink drying or foreign matter in the liquid, and ink droplets may not fly out of the nozzle and recording may not be possible. Therefore, there is a demand for a device that does not become clogged due to ink drying or foreign matter in the liquid.

[Conventional technology]

FIG. 4 is a diagram illustrating a conventional inkjet recording apparatus.

In FIG. 4, the inkjet recording apparatus includes recording paper 1
The platen 2 and the ink generator 1-head (hereinafter referred to as the print head) 3 face each other via the ink tank I4 (not shown in FIG. 5, which will be described later). 'It is fired towards K1. The print head 3 is moved parallel to the platen 2 by the carrier 4 and prints.

It should be noted that the clogging prevention cap 5 is located outside the printing area as shown by the dotted line, and is configured to cover the printing head 3 when not printing. 6 is a guide bar, 7 is a feed screw, and 8 is a motor.

Fig. 5 shows a conventional horizontally moving head. In FIG. 5, there are a plurality of pressure chambers 10 inside the print head 3, and the pressure chambers 10 are connected to a nozzle 12 and a common ink chamber 1 by a conduction path 11 at the front and back.
3. Note that the common ink chamber 13 is connected to an ink tank 14.

Ink is ejected from the nozzle 12 by driving a piezoelectric transducer (piezoelectric element) that is integrated with the pressure chamber 10 . The problem with this ink jetting is that if the ink dries or if foreign matter is present in the ink liquid, the nozzle 12 will become clogged and the jetting will stop.

For this reason, for example, in US Pat. No. 4,308,547, a spherical piezoelectric transducer 15 is submerged in the ink liquid 16 so that its focal point a coincides with the liquid level, and the acoustic energy is transmitted to the focal point a. A method of ejecting liquid in a concentrated manner, so-called nozzle-less inkjet, has been proposed. 18 indicates an electrode.

Furthermore, it is also conceivable to make the piezoelectric transducer 15 into a gutter shape and form it into a line.

Further, as shown in FIG. 7, flat piezoelectric transducers 19a and 19b with a gap at the focal point a are placed on the liquid surface, and a reflecting plate 20 with a parabolic surface is provided in the ink liquid 16. It has also been proposed that the acoustic energy reflected by the reflection plate 20 be concentrated at a focal point a to eject ink. 21 is a piezoelectric transducer terminal, and 22 is a liquid droplet.

[Problems to be Solved by the Invention] Conventional nozzle-less inkjet is a dot-like jet, and in order to make this into a line and increase the printing speed, the piezoelectric transducer 15 shown in FIG. When the reflecting plate 20 is shaped like a gutter and a line-shaped focal point is formed, the ink meniscus 23 has a uniform height as shown in FIG. 8, so no ink is ejected. Therefore, in order to eject ink, it is necessary to control the ink ejection position on line L, but there is a problem in that there is no effective method for controlling the ink ejection position.

Therefore, an object of the present invention is to provide a nozzle-less inkjet recording apparatus that can control the ink ejection position on a line.

[Means to solve the problem]

The above-mentioned problem lies in the nozzle-less inkjet recording device which concentrates the acoustic energy at one point or in a line on the surface of the ink liquid and ejects the ink from the liquid surface, as shown in FIGS. 1(a) and 1(b). This problem is solved by the inkjet/1 recording apparatus of the present invention, which uses a liquid table having an electrorheological effect on the ink and also includes an electrode 25 at the ink ejection position for applying an electric field to the ink.

[Effect]

The present invention makes it possible to accurately control the ink ejection position on a line by giving the ink an electrorheological effect and further providing an electrode 25 for applying an electric field to the ink at the ink ejection position.

That is, the electrorheological effect is a phenomenon in which the viscosity of a liquid increases when an electric field is applied. When a voltage is applied to the electrode 25 at the ink ejection position, the viscosity of the ink increases, so the ink ejection stops and the voltage increases. If you remove it, it will spray again.

In addition, if the focal point is in a line shape and the electrodes are placed closely together and a voltage is applied, the meniscus of the ink at the point where the electric field is applied becomes lower as shown in Figure 2, creating unevenness in the ink and causing the effect of the electric field to decrease. Ink can be ejected from the convex portions that are not covered. In other words, the electric field acts as a nozzle in a conventional inkjet.

In this way, there is no clogging, which is a characteristic of nozzleless printing, and high-speed recording is possible because of the line formation.

〔Example〕

FIGS. 1A and 1B are explanatory diagrams of an embodiment of the present invention. Note that the same reference numerals indicate the same objects throughout the figures.

In FIG. 1(A), the head is composed of planar piezoelectric I-transducers 19a and 19b and an ink tank 24 having a parabolic reflector 20 at the bottom.

The bottom of the ink tank (aluminum material) 24 is shaped like a parabolic gutter, and its focal point a is the piezoelectric transducer 19a, 1
Set in a line shape in the middle of 9b. Piezoelectricity! - The lance gauges 19a and 19b are located on the ink surface, and a hydrostatic pressure is applied to the gap b (the gap is, for example, 0.5 to 1 mm) from an external ink tank (not shown).

Gap b of piezoelectric transducer 19 (ink injection position)
Then, electrodes 25 for applying an electric field to the ink are provided closely as shown in FIG. 1(b). 26 is an insulator.

Furthermore, in the present invention, an electrorheological liquid 32 is used as the ink. The electrorheological liquid 32 is made of a solvent (oil is required as a solvent, such as silicone oil or liquid paraffin) and fine powder (hydrophilic particles with a particle size of 0° otpm to 0.1
/Jz φ and fine S ioz, S 102Affz
03, etc.), a surfactant, and a pigment (phthalocyanine, etc.).

By supplying power to the piezoelectric transducers 19a, 19b, the piezoelectric transducers 19a, 19b
produces vibrations in the thickness direction and emits acoustic energy. This acoustic energy is reflected by a reflection plate 20 having a radiation surface and concentrated in a slit-shaped gap. In this state, (8th
(See figure) Since the ink meniscus is continuous in the slit direction, the ink does not become particles (sprayed). By applying an electric signal to the electrode terminal 27 and applying a voltage (~100V) to any electrode 25 facing each other across the gap, the viscosity of the ink between any electrodes increases. This creates a low area in the ink meniscus, and the ink in the area where there is no electric field is ejected. Here, the electric field can be thought of as playing the role of a conventional inkjet nozzle.

In this way, by giving the ink an electrorheological effect and further applying an electric field to the ink at the position of the ink jet, ink can be jetted at any location in the linear gap (Srin l') b at any time. can.

Note that one side of the electrode 25 may be used as a common electrode over the entire surface, and the electric field may be scanned on the other side.

FIG. 3 is an explanatory diagram of another embodiment of the present invention.

In FIG. 3, 28a and 28b are electrode substrates;
Reference numeral 5 denotes an electrode, 27 an electrode terminal, and 29 a gutter-shaped piezoelectric transducer, which were placed in the ink so that the center was between the electrodes 25. 30a and 30b are electrodes for the piezoelectric transformer, and 31a and 31b are electrode terminals.

The ink used, the principle of ink ejection, the function of the electrodes, etc. are the same as those in the embodiment shown in FIG. 1, so their explanation will be omitted.

[Effects of the Invention] As explained above, according to the present invention, ink is given an electrorheological effect and an electric field is applied to the ink at the ink ejection position, thereby making it possible to accurately eject the ink on the line. can be controlled. This prevents clogging, which is a feature of nozzleless printing, and allows high-speed recording because it uses a line method.

[Brief explanation of drawings]

Figures 1 (A) and (B) are explanatory diagrams of one embodiment of the present invention, Figure 2 is a diagram of a meniscus of the present invention, Figure 3 is an explanatory diagram of another embodiment of the present invention, and Figure 4 is an explanatory diagram of another embodiment of the present invention. Figure 5 is a diagram explaining a conventional inkjet recording device; Figure 5 is a diagram explaining a conventional head structure; Figure 6 is an illustration of a conventional nozzle-less inkjet; Figure 7 is an illustration of another conventional nozzle-less inkjet. , FIG. 8 is a diagram illustrating a conventional meniscus on a line. In the figure, 19 is a piezoelectric transducer, 25 is an electric field generating electrode, 26 is an insulator, 27 is an electrode terminal, 28a and 28b are electrode substrates, 29 is a gutter-shaped piezoelectric transducer, and 30a and 30b are piezoelectric transducers. electrode, 2
4 Ishifufu/No.8 of the present invention -r force self-equivalent Figure 1 Figure Honfu August/Ninu 7th Figure 21211 1b is the electrode terminal 1; Figure 5 Figure 5 shows the four nozzles of the conventional nozzle-less inter-eparator soup.゛／Ri゛Duet me wo θn(2
) is also ward I, t4 line up menu VS E evening relaxation θn (2] No.

Claims (2)

[Claims] (1) A nozzle-less inkjet recording device that ejects ink from the surface of the ink by concentrating acoustic energy on one point or in a line on the surface of the ink, in which a liquid (32) having an electrorheological effect is used as the ink; . A nozzle-less inkjet recording apparatus, characterized in that an electrode (25) for applying an electric field to the ink is provided at the ink ejection position. (2) Claim 1, wherein the electrodes (25) are arranged closely, and the on/off of ink jetting is controlled by a voltage to record an image.
The nozzle-less inkjet recording device described in Section 1.