JPH0448625B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ink recording head that records and displays characters, figures, images, etc. using electroosmosis.

Conventional Structure and Problems In an ink recording head that records and displays characters, figures, images, etc. in ink using electroosmosis, a liquid ink containing a first electrode is placed on a dielectric supporting base material surface. A porous body having a movable depressed groove portion and having a two-dimensional spread such as a film or a plate is installed and bonded on the surface of the dielectric support base material, and a first electrode of this porous body A second electrode is positioned on the opposite side of the porous body to supply and impregnate the porous body with liquid ink, and a signal voltage is applied between the first and second electrodes to apply the liquid ink to the porous body. The relationship is such that the liquid ink is moved through the depressed groove by electroosmosis, and the amount of liquid ink on the tip end side of the first electrode is electrically controlled.

Using this ink recording head, the first
A contact method in which a controlled liquid ink on the electrode tip side is directly contacted and transferred to a recording medium, an electro-osmotic jet method in which the liquid ink is attached to the surface of a recording medium using electro-osmotic pressure against a porous body, and recording. Flying to the surface of the recording medium due to Coulomb force through the medium,
An ink recording device that records and reproduces characters, figures, images, etc. can be realized by the Coulomb force flight method and the like.

In this type of ink recording head, at the tip of the first electrode, in order to move and concentrate the liquid ink toward the tip of the first electrode via the recessed groove.
The depressed grooves and the porous body must be sealed with an adhesive to prevent liquid ink from flowing back.

This sealant must not only prevent backflow of the liquid ink, but also must not inhibit the electroosmotic properties of the liquid ink.

In addition, the porous body should be installed and bonded on the surface of the dielectric support base material, and it is also preferable that the sealant seeps onto the surface of the dielectric support base material during the sealing process. do not have.

As mentioned above, conventional ink recording heads are
The recessed groove in which the first electrode is accommodated must be sealed together with the porous membrane using a sealing agent, which causes problems in the selection of the sealant or the sealing process, which poses a major problem in producing the ink recording head.

Purpose of the Invention The present invention addresses the problems encountered in producing an ink recording head in which a recessed groove in which a first electrode is housed is sealed together with a porous film using a sealing agent. The purpose is to provide.

Structure of the Invention The present invention provides an ink recording head in which a recessed groove part that accommodates a first electrode and extends toward the rear end of the electrode terminates at a distance from an edge of a dielectric support base material. , the rear end side of the first electrode is connected to a power feeding extraction electrode provided on the surface of the dielectric support base material, and passes through this connection to the porous body and the second electrode. position the electrode. Furthermore, the width of the depressed groove at the connection part between the first electrode in the depressed groove and the extraction electrode for power supply,
By forming the groove narrower toward the extraction electrode side, it is possible to prevent the backflow of ink in the recessed groove, eliminate the sealing process using a sealant, and improve problems caused by the sealing process. This facilitates the connection between the electrode and the extraction electrode.

DESCRIPTION OF THE EMBODIMENTS The embodiments of the present invention will now be described in detail. FIG. 1 is an embodiment of an ink recording apparatus using electroosmosis according to the present invention, and is a diagram showing its perspective partial structure and power supply system.

FIGS. 2a to 2c are diagrams showing the connecting portion between the first electrode accommodated in the recessed groove and the lead-out electrode for power supply according to the present invention.

In FIG. 1, 100 is an ink recording head;
A liquid ink 200 is housed in an ink container 300 and is supplied to and impregnated into the ink recording head 100 using the capillary action of the sponge 700.

400 is a signal voltage source, 500 is a recording sheet such as paper, and 600 is a recording medium 500 connected to the edge 13 and side edge surface 1 of the ink recording head 100.
This is a pressure roller made of rubber or the like that is pressed against the roller 2 and feeds the paper in the direction of arrow 501 in the figure.

10 is a support substrate made of a plate-shaped dielectric base material such as borosilicate glass.

The depressed groove 16 in which the first electrode 20 is accommodated on the support substrate 10 has a width of 50 to 70 μm and a depth of 3 to 8 lines per mm, depending on the desired recording resolution.
It extends from the tip 21 of the first electrode 20 to the opposite side in a range of about 20 to 50 μm, and ends with a distance from the edge of the support plate 10, and the length is, for example, 30 mm.
That's about it. An extraction electrode 22 for power supply is installed on the support substrate surface 11 on the opposite side of the tip 21 of the first electrode 20, and this extraction electrode 22 is connected to the first electrode 20 in the recessed groove 16. .

Further, the width of the recessed groove 16 at the connection portion 17 between the first electrode 20 and the power supply extraction electrode 22 in the recessed groove 16 is formed to become narrower toward the extraction electrode 22 .

FIG. 2a is a plan view showing the connection part 17 between the first electrode 20 and the power supply extraction electrode 22 when borosilicate glass is used for the support substrate 10 and the recessed groove 16 is formed by etching with hydrofluoric acid. , Figure b, and Figure c are sectional views along A-A' and B-, respectively.
B′ cross-sectional view.

The depressed grooves 16 are formed in the borosilicate glass 10 by forming a protective film of chromium or the like on the borosilicate glass surface 11 in advance, and then etching the borosilicate glass 10 with a hydrofluoric acid etching solution. Due to the nature of the depression groove 16 formed in this way,
Due to the side etching of the borosilicate glass 10, the side walls 18 of the depressed trenches have an inclined shape.

A first electrode 20 made of a metal film is deposited on the bottom 19 and further on the side wall 18 of the depressed groove 16, and the first electrode 20 is made of a metal film deposited on the borosilicate glass surface 11. It is connected to the extraction electrode 22 via the inclined portion of the depressed groove side wall 18 . The electrodes 20 and 22 are formed on the entire surface of one side of the support substrate 10.
It can be obtained by depositing a metal film such as Au and then etching it into the required pattern.

A good way to connect the first electrode 20 and the extraction electrode 22 is to make the width of the extraction electrode 22 larger than the width of the recessed groove 16 in which the first electrode 20 is accommodated. In a configuration in which high-density recording is performed by narrowing the electrode gap between the electrodes 20 and the extraction electrodes 22, this is not preferable because it causes dielectric breakdown between the electrodes. Therefore, as shown in FIG. 2a, the width of the extraction electrode 22 is preferably equal to or smaller than the width of the recessed groove 16 in which the first electrode 20 is accommodated.

That is, as in this embodiment, the connection portion 17 between the first electrode 20 and the extraction electrode 22 in the depressed groove 16
If the width of the depressed groove and the width of the first electrode on the supporting substrate surface are narrowed toward the extraction electrode 22, the bottom 19 of the depressed groove 16 can be narrowed within a limited range.
The contact length between the side wall 18 and the side wall 18 of the recessed groove 16 and the extraction electrode 22 on the support substrate surface 11 is increased. Therefore, the electrical connection between the electrodes 20 and 22 in the connecting portion 17 becomes extremely easy even in a high-density recording configuration, and disconnection or the like can be prevented.

Thus, on this support substrate surface 11, there is a porous membrane 40 that has holes or gaps that substantially penetrate in the thickness direction, and through which the liquid ink 200 can permeate in the thickness direction.
and, for example, 100 per inch on the porous membrane 40.
Liquid ink 200 with a thickness of about 50 to 300 μm provided with penetrating pores (not shown) with a density of about 300 meshes, a second electrode 50 made of a transparent stainless steel plate or metal mesh, etc. is pulled out and the electrode 22 and a depressed groove are formed. 1
6, the porous membrane 40 is pressed and fixed by the second electrode 50, and a groove gap 30 is formed between the porous membrane 40 and the surface of the first electrode 20. do.

By covering the connecting portion 17 in this way, the porous membrane 4
0. By installing the second electrode 50, it is possible to prevent the liquid ink concentrated in the groove gap 30 from flowing back, as will be described later.

As the porous membrane 40, a so-called microporous membrane filter made of cellulose acetate having a thickness of 20 to 200 μm, an average pore diameter of 0.1 to 8 μm, and a porosity of about 60 to 80% is used, for example.

As the porous membrane 40, other plastic materials, glass, porcelain materials, etc. can be used as necessary.

It is preferable that the edge 41 of the porous membrane 40 be located inside, for example, about 50 to 300 μm from the edge 13 of the support substrate 10, so that an exposed edge surface 14 is formed on the surface 11 of the support substrate. The formation of the edge surface 14 is as follows:
The electric convergence effect of the liquid ink utilizing the electroosmotic property of the liquid ink 200 on this surface 14 can be utilized, which is useful for high-resolution recording. porous membrane 40
The width determines the amount of ink supplied to the tip 21 of the first electrode 20, so it is selected as wide as necessary, for example, 20 mm or more.

Note that the second electrode 50 can be configured to be permeable to the liquid ink 200 by applying a thin layer of conductive paint such as graphite to the surface of the porous membrane 40 .

The liquid ink 200 is made of a liquid material made of, for example, γ-methacryloxypropyltrimethoxysilane, which provides good electroosmotic properties to the porous membrane 40 and the supporting substrate 10, and includes a necessary binder agent and charge control agent. The oil-soluble ink 200 is constructed by mixing, for example, an oil-soluble dye or the like in an amount of about 2 to 5% by weight together with a surfactant and a surfactant.

This type of ink can be electroosmotic into the above-mentioned porous membrane 40 and supporting substrate 10 in the direction of the negative electrode.

The speed of this electroosmosis increases with the applied signal voltage, but its maximum amplitude is set so that the electric field strength does not exceed, for example, 2 V/μm, taking into account dielectric breakdown.

Each of the first electrodes 20 serving as recording electrodes is connected to a signal voltage source 400, and signal voltages V _B and V _B ' are selectively applied between the second electrode 50 and the first electrode 20.

Now, as a signal voltage as shown in the figure, the first electrode 2
Off-voltage V _B ′ where the second electrode 50 is negative with respect to 0,
On the other hand, the operation will be explained by taking as an example a case where the electrode 20 alternately applies a negative on-voltage V _B to the electrode 50. In the part where V _B ' was applied, from the first electrode 20 side forming the positive electrode to the second electrode 50 side forming the negative electrode, via the porous membrane 40,
As the liquid ink 200 electro-osmoses as shown by arrows 210 and 213, the electrode tip 21
The liquid ink 200 located on the side and edge portions 13 is also sucked up to the second electrode 50 side through the groove gap 30, as indicated by arrows 211 in the figure.

Furthermore, the surface 11 of the support substrate 10 is also coated with the porous film 40.
Since it is configured to have the same electroosmotic polarity as , from the electrode 20 side to which V _B ' is applied,
V _B is applied to form a negative electrode, adjacent electrode 2
The liquid ink 200 electroosmoses on the support surface 11 such as the electrode gap surface 15 including the exposed edge surface 14 within the arrangement range of the electrode 2 as shown by the arrow 212 toward the 0 side.

Therefore, the first electrode 20 to which V _B ' is applied
Liquid ink 200 cannot exist on the tip end 21 side or the exposed edge surface 14 around it.

On the other hand, in the first electrode 20 portion to which V _B is applied,
The liquid ink 200 passes through the second electrode 50 and electroosmoses through the porous membrane 40 as shown by the arrow 220 and concentrates toward the surface of the first electrode 20 .

Since the connecting portion 17 opposite to the tip portion 21 of the first electrode 20 is pressed and fixed by the porous membrane 40 and the second electrode 50, the liquid ink 2
00 is transmitted through the surface of the first electrode 20, that is, the groove gap 30, due to its electroosmotic property, and is transmitted through the arrow 22 in the figure.
1, it is pushed out toward the tip end 21 side, and corresponding to the electrode 20 on the exposed edge surface 14 side, position control and
A liquid ink portion 222 is formed in which the amount of ink is controlled with respect to the amplitude of _VB .

In addition, the liquid ink 200 electropenetrates from the side of the adjacent positive electrode 20 through the supporting substrate surface 11 and the exposed edge surface 14 as indicated by the above-mentioned arrow 212, and reaches the surface of the electrode 20 in the depressed groove 16. get together. Due to this extrusion effect and the convergence effect on the exposed edge surface 14, the liquid ink portion 222 can be effectively formed limited to the electrode surface of the electrode tip portion 21.

In order to effectively utilize the suction, extrusion, and convergence effects of the liquid ink 200 as in the present principle, the edge 41 of the porous membrane 40 and the edge 13 of the support substrate 10 are
It is desirable to keep the edge portions 14 and 13 parallel to each other by keeping the distance between them constant; if the gap, that is, the width of the exposed edge surface 14 is too narrow, the convergence and concentration effect of the liquid ink 200 on the surface 14 will be reduced. If the width is too wide, the ink 200 on the _tip 21 that should be suctioned cannot be completely suctioned and remains, reducing the quality of the recorded image. From the above, the width is usually selected to be about 50 to 300 μm as described above.

A recording paper with a thickness of about 80 μm is used as the recording medium 500, and the off-voltage V _B ′ has a constant amplitude of 150 V, for example.
In addition, if the on-voltage V _B is the opposite polarity to V _B ′ and the maximum amplitude is 150 V, and amplitude modulation and pulse width modulation are performed in this range depending on the recording density, the electrode to which voltage V _B is applied will be adjusted according to the voltage value. A liquid ink portion 222 with a controlled amount of ink is generated at the tip 21, and the ink adheres 24 to the surface of the recording medium 500 due to contact transfer.
0, and on the other hand, no ink adhesion 240 occurs because no liquid ink portion 222 exists at the electrode tip 21 where V _B ' is applied.

In this way, characters, figures, images, etc. are displayed in ink recording.

Effects of the Invention As described above, in the present invention, the recessed groove portion that accommodates the first electrode and extends toward the rear end of the electrode is spaced apart from the edge of the dielectric support base material. The rear end side of the first electrode is connected to a power feeding extraction electrode provided on the surface of the dielectric support base material, and the porous body and the second electrode are connected to each other over this connection part. The second electrode is positioned, and the width of the recessed groove at the connection part between the first electrode and the power feeding extraction electrode in the recessed groove part is
By forming the groove so that it becomes narrower toward the extraction electrode side, it is possible to prevent the backflow of ink in the recessed groove without the need for a sealant, and to facilitate electrical contact at the connection part. have an effect.

This is very useful in producing ink recording heads, since it eliminates the step of sealing depressed grooves with adhesive, which was a problem in producing conventional ink recording heads.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an ink recording head in one embodiment of the present invention, and FIG.
Figure b is a sectional view taken along line A-A' in figure a, Figure c is a cross-sectional view of figure a.
It is a BB' sectional view of . 10... Support substrate made of dielectric base material, 16...
... Depression groove, 20 ... First electrode, 22 ... Extraction electrode, 30 ... Groove gap, 40 ... Porous body, 5
0... Second electrode, 100... Ink recording head, 200... Liquid ink, 300... Ink container, 400... Signal voltage source, 500... Recording body,
600...Press roller, 700...Sponge body, _VB ...On voltage, _VB '...Off voltage, 17...
...Connection part between the first electrode and the extraction electrode, 18...
Sinkhole side wall, 19...Sinkhole bottom.

Claims (1)

[Scope of Claims] 1. A recessed groove portion on the surface of the dielectric support base material in which liquid ink containing the first electrode can move, and having a two-dimensional spread on the surface of the dielectric support base material. A porous body is bonded to the porous body, and the liquid ink permeable second
the liquid ink is supplied to and impregnated into the porous body, and a signal voltage is applied between the first and second electrodes to electroosmose the liquid ink into the porous body. The ink recording head is configured to electrically control the amount of liquid ink on the tip end side of the first electrode by moving the liquid ink through the recessed groove portion,
The depressed groove portion extends from the front end side to the rear end side of the first electrode, and terminates at a distance from the edge of the dielectric support base material, and
The rear end side of the electrode is connected to a power feeding extraction electrode provided on the surface of the dielectric support base material, and the porous body and the second electrode pass through this connection part. An ink recording head characterized by having electrodes positioned therein. 2. The ink recording head according to claim 1, wherein the width of the recessed groove portion at the connection portion between the first electrode and the power supply extraction electrode is narrower toward the extraction electrode side. .