JPH04327945A - Ink jet printing head - Google Patents

Abstract

PURPOSE:To provide an ink jet printing head which enables data to be printed in high density and quality, and is not costly. CONSTITUTION:Individual ink flow paths 2a to 2d which extend from the rear end to the front end of a substrate (base) are formed at a fixed interval and at the same time, a common ink supply path is formed near the end of the substrate 1. In addition, an elastic plate 5 is provided on the surface of the substrate 1 where the ink flow path is formed, and individual conductors 6a to 6a are provided on the part above the ink flow path of the elastic plate 5, while a common conductor 7 is provided on the part other than above the ink flow path. Further, an elastic plate 8 is junctioned to the elastic plate 5 in such a manner that the individual and common conductors 6a to 6d, 7 are sandwiched in between, and magnets are arranged on both right and left sides of the substrate 1 respectively. These magnets and conductors are covered entirely with a magnetic shield 11. If an electric current is allowed to run to an area between any individual conductor and any common conductor, the individual conductor receives an electromagnetic force F in an arrow direction as a magnetic field H is applied, and the parts where the individual conductor is positioned of the elastic plates 5, 8 become curved into the ink flow path with the individual conductors to squeeze out ink from the ink flow path.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel inkjet printhead that ejects ink using Fleming's left-hand rule.

0002

2. Description of the Related Art One type of ink jet print head uses an electrostrictive element. This print head generally surrounds individual ink paths that branch off from a common ink path with an electrostrictive element, and applies an electric field to the electrostrictive element to displace the electrostrictive element. It is pushed out from the tip of the tract.

[0003] Furthermore, in order to improve the printing quality and to increase the definition, it is also practiced to tilt the head with respect to the scanning direction of the head to increase the density of printed dots.

0004

[Problems to be Solved by the Invention] However, in the printing mechanism employed in general inkjet printheads, including the above-mentioned printhead, it is important to improve the printing quality by making the printing dots denser than ever before. It is extremely difficult. Therefore, an object of the present invention is to provide an inexpensive inkjet print head that achieves high density and high quality printing.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the inkjet print head of the present invention has a plurality of ink flow paths extending from one end to the other end formed at regular intervals on the surface of the base, An elastic plate is provided on the surface of this base, individual conductors are provided on the part of the elastic plate on the ink flow path, and a common conductor is provided on the part of the elastic plate that is not on the ink flow path, so that the base in the direction in which the ink flow path extends. It is characterized by having magnetic field generating means arranged on both sides.

The print head of the present invention incorporates a completely new printing mechanism, and in principle utilizes Fleming's left-hand rule. As is well known, this law states that the force (electromagnetic force) that a minute portion of a conductive wire through which a current flows is exerted by a magnetic field is This is the rule that the thumb points perpendicular to the index finger.

This law has been widely applied to electric motors, etc., and in the print head of the present invention, the current flowing through the individual conductors provided on the ink flow path of the elastic plate on the surface of the base reaches one end of the base. The ink flows from the ink flow path toward the other end, and a magnetic field is applied in a direction across the ink flow path by magnetic field generating means arranged on both sides of the base in the direction in which the ink flow path extends. Therefore, since the direction of the current and the direction of the magnetic field are orthogonal,
When a current is passed through an individual conductor on an arbitrary ink flow path, the individual conductor is displaced by an electromagnetic force in a direction perpendicular to the direction of the current and the direction of the magnetic field, that is, in a direction toward the ink flow path. The corresponding portion of the elastic plate is curved. As a result, the corresponding portion of the elastic plate enters the ink flow path, the ink flow path becomes shallower, and the ink that has been supplied to the ink flow path is pushed out from the tip end of the ink flow path. On the contrary,
The ink may be moved slowly to deepen the ink flow path, and the ink may be pushed out by quickly returning.

[0008] The base used for the print head of the present invention is
It is not specified as long as it is easy to form an ink flow path. As such a base, a substrate made of resin molding or photosensitive glass etching is best. The elastic plate provided on the surface of the base is such that when the individual conductor provided on the part of the elastic plate above the ink flow path receives an electromagnetic force in the direction toward the ink flow path, the corresponding part of the elastic plate provided with the individual conductor It is best to use a material that quickly curves into the ink flow path together with the individual conductors. For this purpose, it is best to select a material with a low Young's modulus, specifically a Young's modulus of at least 1000K.
It is preferable that it is less than g/mm2. Examples of materials having such a Young's modulus include polymeric materials such as polyimide.

In the print head of the present invention, the individual conductors provided on the part of the elastic plate on the ink flow path serve as individual electrodes, and the common conductor provided on the part of the elastic plate not on the ink flow path serves as a common electrode. A current is passed between the electrode and the common electrode. The magnetic field generating means disposed on both sides of the base is for applying a magnetic field perpendicular to the individual conductors among the individual conductors and the common conductors, and examples thereof include magnets and ferromagnetic materials.

[0010] The ink flow path, the elastic plate, and the individual and common conductors provided on the base can be manufactured using existing molds, etching techniques, etc., thereby reducing manufacturing costs.

[0011]

EXAMPLES The inkjet print head of the present invention will be explained below based on examples. FIG. 1 shows a plane of a substrate 1 as a base, and FIG. 2 shows a cross section of the substrate 1 along line XX in FIG. The substrate 1 has a plurality of (four in this embodiment) individual ink channels 2 extending at regular intervals from one end (hereinafter referred to as the rear end for convenience) to the other end (hereinafter referred to as the front end for convenience) of the substrate 1. It has been formed. Each ink flow path 2 has a rectangular cross section and tapers near the front end of the substrate 1.
The front end surface of the substrate 1 serves as orifices 4 (a to d). or,
Each ink channel 2 communicates with a common ink supply channel 3 near the rear end of the substrate 1, and ink is supplied to each ink channel 2 via the common ink supply channel 3.

Further, FIG. 3 shows a plan view of the print head, and FIG. 4 shows a cross section of the head along line Y--Y in FIG. Figure 4
As shown in FIG. 2, an elastic plate 5 made of the low Young's modulus material is provided on the surface of the substrate 1 on the side where the four ink channels 2 (a to d) are formed. Each ink flow path 2 and the common ink supply path 3 are sealed by the elastic plate 5, but in particular, the portion of the elastic plate 5 above each ink flow path 2 is designed to be free from curvature fluctuation. Further, by sealing with the elastic plate 5, it is possible to prevent foreign matter such as dust from entering the ink flow path 2 and clogging the ink flow path 2 and the orifice 4.

In the elastic plate 5, individual conductors 6 (a to d) in the form of elongated rods are formed above each ink flow path 2 in a portion above the ink flow path 2. The tip of the individual conductor 6 is connected to the substrate 1
extends to near the front end (tapered part of the ink flow path 2),
The rear end extends to the rear end of the substrate 1. Further, in the elastic plate 5, a common conductor 7 in the form of a long thin plate is formed in a portion not above the ink flow path 2 (a portion on both left and right sides of the substrate 1). Figure 4
Although not particularly shown, the individual conductors 6 and the common conductor 7 are continuous near the front end of the substrate 1 (the tapered part of the ink flow path 2), and the individual conductors 6 become individual electrodes and the common conductor 7 becomes a common electrode. . When a current is passed between the individual and common electrodes 6 and 7, there is no load between the two electrodes 6 and 7, but since the individual conductor 6 is long and thin and the individual conductor 6 itself has a certain degree of resistance, it is not a load. There is no need to add any resistance. However, if a load is required as desired, a suitable resistor may be connected in the wiring circuit of each individual conductor 6.

Furthermore, in this embodiment, the individual and common conductors 6
, 7 are sandwiched therebetween, and an elastic plate 8 made of the same material as the elastic plate 5 is joined to the elastic plate 5. Therefore, the corresponding portions of the elastic plates 5 and 8 on which the individual conductors 6 are located move together as the individual conductors 6 are displaced. Magnets 9 and 10 are arranged as magnetic field generating means on both side surfaces (left and right sides) of the substrate 1 in the direction in which the ink flow path 2 extends, and a magnetic field H is applied from the right side to the left side of the substrate 1.

As shown in FIGS. 3 and 4, a substrate 1, a substrate 1
The entire structure consisting of the above elements and magnets 9, 10, etc. is covered with a suitable magnetic shield 11, and the magnets 9, 10, etc. inside the structure are covered with a suitable magnetic shield 11.
The magnetic field H caused by 10 is prevented from reaching the outside of the structure, and the individual conductors 6 inside are prevented from malfunctioning due to another magnetic field acting from the outside. As can be seen from FIG. 5, the magnetic shield 11 is also present on the front end surface of the substrate 1, and a portion of the ink flow path 2 facing the orifice 4 is opened as a slit, and the orifice 4 is positioned toward the slit.

Next, the operation of the print head constructed as described above will be described. In FIG. 3, a switch 12 is connected to the wiring circuit of each rod-shaped individual conductor 6, with the individual conductor 6 serving as a positive individual electrode and the common conductor 7 serving as a negative common electrode. Each ink flow path 2 is filled with ink through a common ink supply path 3. Now, if the switch 12b is closed, the current I flows through the corresponding individual conductor 6b in the direction of the arrow. Figure 4
When a current flows through the rod-shaped individual conductor 6b, the magnets 9 and 1
Since the magnetic field H is applied in the direction of the arrow by 0, an electromagnetic force F perpendicular to the direction of the current I and the direction of the magnetic field H acts on the individual conductor 6b in the direction of the arrow according to Fleming's left-hand rule. This electromagnetic force F causes the individual conductor 6b to be displaced downward in FIG. With the displacement of the individual conductor 6b, the individual conductor 6
The corresponding part of the elastic plates 5 and 8 that sandwich b is the corresponding ink flow path 2b
Curve inward as one.

When the corresponding portions of the elastic plates 5 and 8 (particularly the elastic plate 5) enter the ink flow path 2b, the depth of the ink flow path 2b becomes shallow and the ink flow path 2b is blocked by the elastic plate 5. It will look like this. As a result, the ink flow path 2b
The ink present in the ink is pushed and ejected from the corresponding orifice 4b (see FIG. 5). When the switch 12b is opened, the individual conductor 6b returns to its original state together with the corresponding portions of the elastic plates 5 and 8, and ink is newly supplied to the ink flow path 2b.

When a current is applied to any individual conductor 6 in this way, the corresponding part of the elastic plate 5 (also the corresponding part of the elastic plate 8) where the individual conductor 6 is located moves downward into the ink flow path 2. The ink enters the ink flow path 2, and the ink inside the ink flow path 2 is pushed out. In the above embodiment, the electromagnetic force F acting on the individual conductors 6 is in the direction of the arrow (direction from the top to the bottom in FIG. 7 is positive and the direction of the magnetic field H is reversed, the electromagnetic force F similarly takes the direction shown in FIG. 4 due to Fleming's left-hand rule.

Further, in the above embodiment, the ink flow path 2 on the surface of the substrate 1 is arranged so as to face upward, but it may be arranged so as to face downward. That is, even with a structure in which the print head shown in FIG. 4 is reversed, exactly the same operation and effect can be obtained. However, in this case, since the elastic plate and the individual conductor are present below the ink flow path, the electromagnetic force acts in the upward direction, causing the individual conductor to be displaced upward together with the corresponding part of the elastic plate. , it is important to narrow the ink flow path. To do this, the direction of the current or the direction of the magnetic field is shown in Figure 3.
The direction may be opposite to the direction of the current I shown in FIG. 4 or the direction of the magnetic field H shown in FIG.

[0020]

Effects of the Invention Since the inkjet print head of the present invention is constructed as described above, if a current is passed through the individual conductors provided on the ink flow path of the elastic plate, the current will be reduced according to Fleming's left hand rule. An electromagnetic force in a direction perpendicular to the direction of the magnetic field acts on the individual conductor, and this electromagnetic force displaces the individual conductor toward the ink flow path, causing the corresponding part of the elastic plate provided with the individual conductor to move into the ink flow path. This is an epoch-making device in that the ink inside the ink flow path is pushed out.

Therefore, the print head of the present invention achieves high printing density and high printing by narrowing the width of the ink channels formed on the surface of the base and the spacing between the channels as much as possible. Quality can be easily achieved. Furthermore, since the ink channels, elastic plates, individual and common conductors can be manufactured at low cost using known molds, etching techniques, etc., a print head with the above structure can be provided at low cost.

[Brief explanation of drawings]

FIG. 1 is a plan view of a substrate on which a plurality of ink channels are formed in an inkjet printhead of the present invention.

FIG. 2 is a cross-sectional view of the substrate shown in FIG. 1 taken along line XX.

FIG. 3 is a top view of an inkjet printhead of the present invention.

FIG. 4 is a cross-sectional view of the print head shown in FIG. 3 along line Y-Y.

FIG. 5 is a front view of the print head shown in FIG. 3;

[Explanation of symbols]

1 Substrate (base) 2 Individual ink flow path 3 Common ink supply path 4 Orifice 5, 8 Elastic plate 6 Individual conductor (individual electrode) 7
Common conductor (common electrode) 9, 10 Magnet (magnetic field generating means) 11 Magnetic shield

Claims (1)

[Claims] Claim 1: A plurality of ink flow paths extending from one end to the other end are formed at regular intervals on the surface of a base, an elastic plate is provided on the surface of the base, and a portion of the elastic plate on the ink flow path is provided with an elastic plate. An ink jet print head characterized in that individual conductors are provided, a common conductor is provided in a portion of the elastic plate that is not on the ink flow path, and magnetic field generating means are respectively arranged on both sides of the base in the direction in which the ink flow path extends.