JP2003165227A - Orifice plate of ink-jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the trouble that a large amount of ink is consumed and using ink by not smaller than required is not economical in printing large-sized posters or the like, and setting off to papers intensifies because the penetration of ink in a perpendicular direction of papers proceeds when an ink drop amount is increased so as to obtain necessary dots in a high-quality image field. <P>SOLUTION: A surface of the orifice plate is formed of an ink repellent coating layer, and a region having lower ink repellency than that of the surface of the orifice plate is formed to a part of nozzle openings. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an orifice plate of an ink jet type recording apparatus.

[0002]

2. Description of the Related Art Since a recording apparatus equipped with an ink jet recording head can form small dots with high density,
It is used in many types of printing, including color printing. Furthermore, in order to realize higher speed printing, it is necessary to arrange nozzles on the line across the width of the printing paper. In addition, recently, the use of printing large-sized posters for outdoor use with an inkjet recording device has been increasing.

In the ink jet recording apparatus, a pressure generating chamber communicating with the nozzle opening is expanded and contracted by a piezoelectric vibrator to fill the pressure generating chamber with ink and pressurize the ink in the pressure generating chamber to eject the ink from the nozzle opening. Ink droplets are ejected to form dots. The ink droplets become rod-shaped (hereinafter referred to as "ligament") from the nozzle opening due to the pressure rise from the pressure generating chamber, and the ink is ejected, and the ink is separated by the surface tension of the ink and the force of returning to the inside of the nozzle. The droplets fly as ink droplets and land on the recording paper to form dots.

On the other hand, in order to improve the print quality,
It is necessary to prevent bleeding on the recording paper. If the amount of ink droplets is reduced to prevent bleeding and the dot size on the recording paper becomes smaller, the required area cannot be filled as a result. In addition, since printing results are viewed from a relatively distant position for large-sized posters as described above, high-definition printing is not so necessary, and a printing density of about 360 dpi is often sufficient, and printing is performed with a large dot size. To be done.

However, even if the amount of ink of one drop is increased, the dot diameter becomes saturated and the dot size cannot be increased. Further, in the case of the large-sized poster printing as described above, since a large amount of ink is consumed, it is not economical to use more ink than necessary. Further, even in the field of high image quality, if the amount of ink droplets is increased in order to obtain the required dot size, the ink penetrates in the vertical direction of the paper, and the set-off on the paper becomes severe. Further, the drying of the ink is also slowed down, and stacking the sheets of paper after printing end up rubbing by the sheets of paper and transfer of the ink, which deteriorates the print quality.

[0006]

It is not economical to use more ink than is necessary because large amounts of ink are consumed in the case of large-sized poster printing and the like. Further, even in the field of high image quality, if the amount of ink droplets is increased in order to obtain the required dot size, the ink penetrates in the vertical direction of the paper, and the set-off on the paper becomes severe. In addition, the drying of the ink will be slowed down, and stacking paper after printing is
Rubbing by paper and transfer of ink will lead to deterioration in print quality.

An object of the present invention is to reduce the consumption of ink as much as possible and to increase the dot size on recording paper.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a common ink chamber provided outside and receiving ink from an ink tank, and a pressure for receiving ink through the ink supply port from the common ink chamber. A chamber plate having a generating chamber; a diaphragm plate having a diaphragm portion facing the pressure generating chamber; and a nozzle opening for ejecting ink droplets by expanding and contracting the pressure generating chamber with a piezoelectric vibrator. An ink jet recording head comprising a flow path unit sealed by an orifice plate provided, wherein the surface of the orifice plate is made of an ink-repellent coating layer, and a part of the nozzle opening is formed in the orifice plate. It is characterized in that a region having lower ink repellency than the surface is formed.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to Examples. FIG. 1 is a sectional view of a head module of an ink jet recording head equipped with the present invention. The recording head 1
Orifice plate 2 having a plurality of nozzle openings 21
And the supply passage 32 from the common ink chamber 31 and the pressure generating chamber 3
A chamber plate 3 having a pressure generating chamber 33
The ink flow path forming member 5 including the diaphragm plate 4 so that the pressure generating chamber 33 can be easily compressed and expanded by transmitting the displacement from the piezoelectric vibrator 50, and the piezoelectric vibrator 50 is a fixed member. It is adhered via 10 to form a head module.

Here, the orifice plate 2 is generally formed by pressing a thin SUS material to open a nozzle opening, or is formed of a Ni material or the like by an electroforming technique.
The chamber plate 3 forming the pressure generating chamber can process the highly accurate pressure generating chamber 33 and the ink supply passage 32 from the common ink chamber 31 by wet or dry etching a silicon wafer. And
The diaphragm plate 4 is a thin SUS material having a thickness of about 10 to 20 μm or a chemically resistant resin material such as polyimide, which is laminated and pressure-bonded with SUS, and is etched so that the portion to which the piezoelectric vibrator is bonded is left in an island shape. And
Those in which the resin portion functions as a diaphragm have been used. An ink repellent film layer is formed on the surface of the orifice plate 2. As the method, various methods have been proposed, and as a typical example, resins such as polytrafluoroethylene, polybarfluoroalkoxybutadiene, and polyfluorovinyl, which are fluorine-based polymer materials used for eutectoid plating treatment. These are used alone or as a mixture.

FIG. 4 shows how ink droplets are ejected from the nozzle openings. First, a voltage is applied to the piezoelectric vibrator 50 to expand the pressure generating chamber 33 due to the contraction of the piezoelectric vibrator 50, and ink flows in from the supply path 32, and at the same time, the meniscus 90 on the ink surface at the tip of the nozzle moves in the direction of arrow A. Retracted (Fig. 4a). Then, the pressure generation chamber is contracted by releasing the voltage applied to the piezoelectric vibrator 50, and the ink is ejected from the nozzle opening (FIG. 4b). However, the ejected ink is not immediately separated due to the viscosity of the ink and becomes a rod shape, and the ink is ejected and the vicinity of the nozzle opening is constricted (B portion) due to the surface tension of the ink (FIG. 4c). Then, the ink is separated and ejected as ink droplets from the nozzle openings (FIG. 4d). Then, it lands on the recording paper 100 as it is to form dots of φD (FIG. 4e).

A feature of the present invention is that the ink repellent film is formed so that the nozzle openings of the orifice plate 2 have different wettability. FIG. 2 shows an embodiment of the nozzle opening 21 of the orifice plate 2 according to the present invention. The ink-repellent film layer 80 is inserted into the nozzle opening 21 by several microns from the tip of the nozzle opening 21. The wettability is enhanced only in a partial area (P portion in FIGS. 2 and 4) of the circumference with respect to other areas. In the case of the embodiment, the area is not subjected to the ink repellent treatment. Therefore, the wettability of the ink is different near the nozzle opening outlet. Due to this difference in wettability, the ink droplets ejected from the nozzle opening 21 are attracted to the highly wettable portion in the nozzle opening 21. At the start of ejection, the pressure in the nozzle is high and the ejected ink droplet has a high energy, so that it is ejected straight in the direction of the normal of the nozzle 21.
However, as the ink droplets are ejected, the pressure drops, and when the ligament is cut, the ink is attracted to the side with higher wettability. Therefore, when the ligament is broken and ejected, the head ink droplet flies slightly by ΔS (FIG. 3a). Then, on the recording paper 100, the landing position of the particles in the ligament portion is displaced, and a larger dot diameter φD1 (φD1> φ).
D) can be formed (Fig. 3b).

In the above-mentioned embodiment, the wettability of a part of the ink repellent film that has entered the inside of the nozzle 21 is changed.
As shown in FIG. 5, the nozzle opening 21 in which the entire surface of the orifice plate is covered with the ink repellent film layer 200 (dotted area)
The same effect can be obtained by uniformly changing the wettability of a part of the outlet surface (part X in FIG. 5) of (3), and an easy configuration can be taken from the manufacturing aspect.

In order to surely bend only the ligament, the area of low wettability is about 1/8 of the circumference of the nozzle.
The following is desirable (Fig. 2). If it exceeds the range beyond this range, the leading ink droplet itself will bend from the beginning. Further, the contact angle with the area ink is 50 ° or less, and the contact angle is 60 at other portions.
It is desirable that the angle be at least °.

Further, it is preferable that the area having high wettability is deviated from the main scanning direction for printing. That is, if the recording paper is conveyed in the direction in which the flight is bent or the head is moved, the direction in which the flight is bent is corrected,
This is because the effect of expanding the dot size is weakened.

Further, since there is a place where the wettability is extremely different greatly, even if there is a slight non-uniform wettability in the other part, the surface energy is low, that is,
The part with high wettability becomes dominant and stable, and it becomes possible to bend the flight.

[0017]

As described above, according to the present invention, the surface of the orifice plate having the nozzle openings for ejecting ink droplets is formed of the ink-repellent coating layer, and a part of the nozzle openings is the orifice. By making the ink repellency lower than that of the surface of the plate or eliminating the ink repellant film layer only in a part of the nozzle opening, it becomes possible to form a large dot with a small amount of ink droplets. It can reduce the consumption and provide an economical printing device.

Further, since the difference in wettability is large, it is possible to cover a slight difference in wettability in the nozzle portion that occurs during the manufacturing process, and it is possible to easily manufacture the head and provide an inexpensive head. Becomes

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a head module of an inkjet recording head including an orifice plate of the present invention.

FIG. 2 is a diagram showing an embodiment of the orifice plate of the present invention.

FIG. 3 is a diagram illustrating an ink droplet ejection state according to the present invention.

FIG. 4 is a diagram showing an ink droplet ejection state of an ink jet recording head according to a conventional technique.

FIG. 5 is a view showing another embodiment of the orifice plate of the present invention.

[Explanation of symbols]

1 is a recording head, 2 is an orifice plate, 3 is a chamber plate, 4 is a diaphragm plate, 5 is a flow path unit, and 21 is a nozzle opening.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshitaka Akiyama             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. F-term (reference) 2C057 AF93 AF99 AG07 AG12 AG44                       AN01 AP02 AP12 AP13 AP22                       AP31 AP38 AP55 AP60 AQ02                       AQ06

Claims (6)

[Claims] 1. A chamber plate provided with a common ink chamber which is provided outside and receives the supply of ink from an ink tank, and a pressure generating chamber which receives the supply of ink through an ink supply port from the common ink chamber. And a diaphragm plate having a diaphragm portion facing the pressure generating chamber, and an orifice plate having a nozzle opening for expanding and contracting the pressure generating chamber with a piezoelectric vibrator to eject ink droplets. An ink jet recording head including a flow path unit, wherein the surface of the orifice plate is formed of an ink repellent film layer, and the ink repellent property is lower than the surface of the orifice plate in a part of the nozzle opening. An orifice plate for an ink jet recording apparatus, characterized by forming a region. 2. A chamber plate provided with a common ink chamber which is provided outside and receives ink from an ink tank, and a pressure generating chamber which receives ink through an ink supply port from the common ink chamber. And a diaphragm plate having a diaphragm portion facing the pressure generating chamber, and an orifice plate having a nozzle opening for expanding and contracting the pressure generating chamber with a piezoelectric vibrator to eject ink droplets. An ink jet recording head including a flow path unit, wherein the surface of the orifice plate is formed of an ink repellent coating layer, and an area having no ink repellent coating layer is formed in a part of the nozzle opening. An orifice plate for an ink jet recording apparatus, which is characterized in that 3. The ink-repellent coating layer of the nozzle opening is formed inside the nozzle for a certain distance to form a region in which the coating layer is not formed. Orifice plate for inkjet recording device. 4. The region where the ink repellent film layer is not formed or where the ink repellent property is low and the wettability is high is within a range of ⅛ or less of the circumference of the nozzle. 2. An orifice plate of the ink jet recording apparatus according to 2. 5. The contact angle with ink in regions having different wettability is 60 ° or more on the low wettability side and 50 ° or less on the high wettability side. Orifice plate for inkjet recording device. 6. The orifice plate of an ink jet recording apparatus according to claim 1, wherein the areas having different wettability do not coincide with the main scanning direction of printing.