JPH02117837A - Ink jet-type printing head device - Google Patents

Abstract

PURPOSE:To restrict generation of a state where a printed surface is contaminated by forming at least part of an external wall for ventilation or a ventilation passage communicating with the former of a moisture absorbing member. CONSTITUTION:Ink droplets discharged from a discharge orifice 11A arrives at a paper surface because of their increased flying speed with the assistance of an air flow (arrow) supplied from an air flow passage 31. If a top plate 21 is for instance, made of stainless plate, ink droplets, losing their right flying direction due to an external disturbance, stick to the interior of a top plate 21A, and then are blown off by the air flow when a certain amount of ink accumulates. These blown ink droplets arrive at the surface of paper and foul the print. If the top plate 21 is made of a stainless fiber plate, the ink droplets penetrate the interior of the top plate due to capillarity, even when the droplets stick to the interiors of through holes 21A on the top plate 21. Consequently, the ink does not accumulate in the through-holes 21A of the top plate or their neighborhood, and thus the printing result is not contaminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet printhead device, and particularly to an inkjet printhead device that has an air flow in the direction of ink ejection.

A relatively large amount of research and development has been conducted on inkjet print head devices. In particular, in order to improve printing quality, we have developed a method that creates airflow from around the nozzle in the direction of ink ejection and increases the flying speed of ink droplets, thereby making the ink droplets reach a predetermined position on the paper surface. Inkjet heads have been relatively widely used in the past.

[Problems to be Solved by the Invention] In the conventional example described above, when an air flow is formed between the nozzle and the paper surface, the outer wall portion of the air flow on the nozzle side is formed of a metal plate or the like. many.

On the other hand, if the ejection direction is incorrect due to disturbances from outside the print head, the ejected ink adheres to the outer wall portion of the air flow path on the head side. In such a case, once the ink adhering to the outer wall portion accumulates to a certain extent, it is blown off by the above-mentioned air flow and adheres to the paper surface, causing a problem of staining the printed surface.

[Conventional technology]

[Object of the Invention] An object of the present invention is to provide an inkjet print head device that can improve the disadvantages of the conventional example and, in particular, can effectively suppress the occurrence of staining of the print surface.

[Means for Solving the Problems] The present invention includes a nozzle portion for ejecting ink, and an air flow that disposes this nozzle portion in the center and guides ink droplets ejected from the nozzle portion toward the paper surface. It is equipped with an outer wall part for ventilation for forming.

A configuration is adopted in which at least a portion of the ventilation outer wall or the ventilation path connected thereto is formed of a hygroscopic member. This aims to achieve the above-mentioned purpose.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG.

The embodiment shown in FIG. 1 includes an inkjet type head body 1, an outer ventilation wall 2 for forming an air flow that guides ink droplets output from the head body toward the paper surface, and an outer wall 2 connected thereto. A ventilation path 3 is provided.

The head body 1 includes a nozzle portion 11 formed at the tip,
It is composed of an ink introduction section 12 that guides a predetermined ejection ink to this nozzle section 11, and a flange section 13 that supports this ink introduction section 12.

Further, in this embodiment, the ventilation outer wall portion 2 and the ventilation path 3 connected thereto are constituted by three laminated plate-like members. These three plate-like members are, in order from the left in Figure 1,
Top plate 21. It consists of a middle plate 22 and a base plate 23.

Among these, the top plate through hole 21A formed in the top plate 21 is the ink discharge port 1 of the nozzle portion 11 described above.
It is arranged so as to surround 1A.

That is, this top plate through-hole 21A constitutes the ventilation outer wall portion 2. Further, the middle plate 22 is formed with a relatively large middle plate through hole 22A that is connected to the top plate through hole 21A described above. The middle plate through-hole 22A is a relatively large through-hole in order to adjust the air pressure so that a uniform pressure air flow is output from the entire top plate through-hole 21A.

An air flow path 31 that is connected to a part of this middle plate through-hole 22A is formed by the base plate 23 and the flange portion 13. An air introduction pipe 32 for introducing air at a predetermined pressure from the outside is connected to this air flow path 31. Then, the air flow path 31 and the middle plate through hole 2
2A constitutes the aforementioned ventilation path 3.

Here, the top plate 21 is formed of a hygroscopic member. In this case, as the hygroscopic member, for example, a sintered particle board member or a metal fiber board member made of fired small particles of plastic or metal is used.

Next, the operation of the above specific example will be explained.

The ink droplets ejected from the ejection port 11A are assisted by the air flow (arrow) supplied from the air flow path 31, and their flying speed is increased, so that they reach the paper surface. In the conventional example, when the top plate 21 is made of, for example, a stainless steel plate, ink droplets whose flight direction is incorrect due to disturbance etc. adhere to the inside of the top plate 21A, and a certain amount of ink accumulates. It is blown away by the airflow and reaches the paper surface, staining the print result. On the other hand, in the case of the embodiment, for example, if the top plate 21 is made of stainless steel fiberboard, even if an ink droplet adheres to the inside of the top plate through-hole 21A, it will penetrate into the inside of the top plate 21 due to capillary action. Therefore, it does not accumulate in or near the top plate through-hole 21A, and therefore does not smear the print result.

In the above embodiment, the top plate 21 is made of a hygroscopic material, but the present invention is not necessarily limited to this. For example, the entire middle plate 22 and base plate 23 may be made of a hygroscopic material. It's okay. Further, a plate piece 30 made of a hygroscopic material may be detachably attached to the outer surface of the top plate 21 as shown in FIG.

[Effects of the Invention J As described above, according to the present invention, since the ink ejection nozzle is surrounded by a structure equipped with a hygroscopic member, the ink that adheres to the ventilation outer wall due to disturbance etc. is effectively absorbed. As a result, the proportion of ink that adheres to the ventilation outer wall and is blown onto the paper by the air flow is significantly reduced, which is an unprecedented advantage in that it can effectively suppress paper stains. An inkjet printhead device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG. 2 is a sectional view showing another embodiment. Engineering...Head body, 2...Outer wall for ventilation, 11...
- Nozzle part, 21.30... Hygroscopic member.

Claims (1)

[Claims] (1) A nozzle part for ejecting ink, and an outer ventilation wall part for forming an air flow that arranges this nozzle part in the center and guides ink droplets ejected from the nozzle part toward the paper surface. An inkjet printhead device comprising: at least a portion of the ventilation outer wall or the ventilation path connected thereto, made of a hygroscopic material.