JPH03166958A - inkjet recording device - Google Patents

Abstract

PURPOSE:To enable accurate stable discharge of hot melt type ink to be performed by a method wherein a plate component having a plurality of nozzles is provided to a box composed of a good heat conductive material equipped with a heat source, and ink which is liquefied by melting is discharged from a nozzle opening with a piezoelectric transducing means arranged to its rear surface. CONSTITUTION:A head frame 7 formed with a good heat conductive metallic material is served concurrently as an ink reservoir 8, and a heating element 9 is arranged on its outside wall. Further, a plurality of nozzle openings 11 are disposed in a row in a carrying direction of a recording medium on a nozzle plate 10 surface on a platen side. Furthermore, a cantilever-like piezoelectric vibrator 12 is fixed to a support substrate 13 keeping a required clearance from the nozzle plate at a position opposed to the nozzle opening 11 inside that. A pattern electrode on the support substrate 13 is electrically connected to the piezoelectric vibrator 12. When voltage is impressed selectively via a lead wire, corresponding piezoelectric vibrator 12 vibrates vertically to the nozzle plate 10 surface, and ink 14 existing between the nozzle plate 10 and the piezoelectric vibrator 12 is pushed to be discharged from the nozzle opening 11 toward a recording medium.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention is an inkjet recorder #! Regarding the apparatus, more specifically, it relates to an inkjet recording apparatus using hot melt ink. 1. Prior Art l As a typical example of the conventional technology, an inkjet recording device such as that disclosed in Mochiseki Publication No. 61-98547 is cited as a typical example, but hot melt ink undergoes a phase change from a solid phase to a liquid phase. If the ink is pressurized by the piezoelectric transformer t*a, the air bubbles will absorb this pressure, and the ink will be damaged, especially if the ink cavity has a closed type ink cavity structure. This causes problems such as the inability to properly dispense the liquid. In order to avoid this problem, when supplying and filling ink from the ink storage section to the ink discharge section, a pressure generation mechanism using pressurization or suction is required. It had the disadvantage that it had to be discharged. ] 3M to be solved by the invention + The present invention was made in view of these problems, and its purpose is to enable accurate and stable ejection of hot-melt ink, and to improve the performance of this type of ink. The objective is to provide an inkjet recording device that can fully utilize its advantageous high printing performance. [Means for Solving the Problem 1] That is, the present invention provides an inkjet recording apparatus for solving the problem, which includes a housing made of a heat conductive material equipped with a heat source, a nozzle plate having a plurality of nozzle ports, and a housing made of a heat conductive material. An ink ejection section consisting of a piezoelectric transducer arranged in an ink chamber so as to face the nozzle opening, and a plurality of rigid members forming a gap between the ink ejection section and the ink storage section to allow ink to be drawn up by capillary force. By providing a slit hole in a part of the nozzle plate, hot melt ink can be ejected accurately and stably to achieve high printing performance. {Example 1 Therefore, the example illustrated below will be explained. FIG. 1 shows a diagonal IE view of a recording apparatus equipped with an inkjet head of the present invention. The inkjet head 1 is mounted on a carriage 3 that runs in the axial direction of a platen 2, and the recording medium 4 is mounted on a guide. It is transported by shafts 5 and 6. Here, the ink ejecting direction of the inkjet head l is set so that it is in the anti-gravitational direction. This is to prevent ink from flowing out from the nozzle opening due to ink head pressure by arranging the ink ejection surface above the ink level in the ink reservoir H8. FIG. 2 shows a cross-sectional view of the inkjet head of the present invention. Reference numeral 7 denotes a head frame made of a metal material with good thermal conductivity, which also serves as an ink reservoir 8, and a heating element 9 is disposed on the outer wall of the head frame. Furthermore, a plurality of nozzle holes 11 are lined up in the direction of conveyance of the recording medium on the nozzle plate lO surface on the platen side, and a cantilever-shaped piezoelectric vibrator 12 is placed on the nozzle plate at a position facing the nozzle hole l1. It is fixed to the support substrate 13 while maintaining the required gap. Pattern on support board 13! The poles and the piezoelectric vibrator 12 are electrically connected, and when a voltage is selectively applied via the lead wire, the corresponding piezoelectric vibrator 12 vibrates in a direction perpendicular to the surface of the nozzle plate 10. The grooves are formed so that the ink 14 interposed between the nozzle plate 10 and the piezoelectric vibrator 12 is pressed and ejected from the nozzle roller 11 toward the recording medium. By the way, when hot-melt ink is melted, bubbles are generated in the ink chamber and ink supply path due to a phase change. , no air bubbles remain in the ink chamber. Ink supplied from the ink reservoir 8 through the plurality of ink supply plates 16 is filled into the gap between the nozzle plate 10 and the piezoelectric vibrator l2 from the tip of the piezoelectric vibrator. Here, the gap between the ink supply plates 16 keeps the ink l4 at a pressure of 11I! due to capillary force. The gap must be small enough to be able to be pulled up to the mover 12, and must be small enough to allow air bubbles generated from the molten ink 14 to escape, as well as to respond sufficiently to continuous ink ejection. It must be something that you have.
Therefore, this ink supply plate 16 is integrated and fixed to the head frame 7 via a spacer of a constant thickness so that a gap satisfying the above conditions is formed. Note that an ink meniscus is formed between the nozzle plate 10 facing the slit hole 15 communicating with the atmosphere and the piezoelectric vibrator 12, and the pressure changes with the displacement of the mover 12, and the surface tension causes the ink meniscus to fill the gap. Ink is replenished. In other words, ink is supplied to the gap between the nozzle hole 11 and the slit hole 15.
The structure is achieved by surface tension acting on both ink menisci. FIG. 3 is a partially enlarged view of the inkjet head IZ of the present invention. The nozzle surface is 20 to 10 from the nozzle plate 10.
It is formed in a shape that protrudes by approximately 0 μm, and the nozzle surface is always exposed from the ink pool remaining on the nozzle plate surface. This is to prevent ink discharge failure caused by ink pooling. Near the fixed end of the nozzle plate 10 to the piezoelectric sensor 12, there is a width of 0.5 mm in the arrangement direction of the nozzle rods 11. A slit hole 15 having a diameter of about 1 to 1.0 mm is formed. As shown in FIG. 4, the slit hole 15 has a pressure of 1:11l! It is also possible to arrange them at a position opposite to the mover, but the shape is sufficiently large relative to the opening area of the nozzle roller 11, and the ink m+: Therefore, the atmospheric communication with the ink chamber is not interrupted. It is necessary to set it. (Effect of the invention 1 As described above, according to the present invention, a plate member having a nozzle of *a is provided in a housing made of a conductive material equipped with an I!! source, and a piezoelectric transducer arranged on the back side of the plate member is provided. Since the ink melted and liquefied by the means is pressurized and ejected from the nozzle opening, the small amount of ink remaining between the plate member and the piezoelectric conversion means is liquefied in a short time, and the ink is made ready for printing. The slit holes provided in the nozzle plate make it easy to discharge air bubbles, and the ink meniscus formed in the slit holes improves ink supply capability, making it possible to realize a highly responsive inkjet head. The integrated structure of the reservoir and ink ejection section has the effect of reducing the size of the head and significantly reducing running costs through effective use of ink.

[Brief explanation of the drawing]

FIG. 1 is a li4 perspective view of an apparatus showing an embodiment of the present invention, FIG. 2 is a sectional view of an inkjet head of the present invention, and FIGS. 3 and 4I2I are partially enlarged views of the inkjet head of the present invention. ．． 1 ... 8 ... 9 ... 10 ... 1 l ... 1 2 ... 1 5 ... 1 6 ... Inkjet head Ink reservoir Heating element Nozzle plate Nozzle mouth Piezoelectric vibrator More than slit hole ink supply plate

Claims (2)

[Claims] (1) A casing made of a thermally conductive material equipped with a heat source, an ink ejection section consisting of a nozzle plate having a plurality of nozzle ports, and a piezoelectric conversion means arranged to face the nozzle ports, and the ink ejection section An inkjet recording device characterized in that a plurality of rigid members are used to form a gap between the ink reservoir and the ink reservoir, and a slit hole is provided in a part of the nozzle plate. . (2) The inkjet recording apparatus according to claim 1, wherein a part of the gap between the piezoelectric conversion means fixed to the housing constituting the ink chamber and the nozzle plate is in communication with the atmosphere.