JPS585267A - Electroosmosis ink recording head - Google Patents

Abstract

PURPOSE:To prevent the impregnation and staying of ink in electrodes for improving the quality of recorded image by forming one of paired electrodes from a metal film in an image recording device in which a signal voltage is applied between paired electrodes to push out ink in a porous material. CONSTITUTION:Ink 200 in an ink container 300 is supplied to an ink recording head 100 by the capillary phenomenon of a sponge material 700. A recording paper 500 is supplied by a press roller 600, and a groove 16 is provided on a support base plate 10 of a dielectric material and its bottom is bonded with the first electrode 20 of a metal film. A porous material 40 is placed on the support base plate 11 and the second electrode 50 is placed on the porous material 40. For the first electrode 20, chromium, for example, is thinly deposited in advance on the electrode 20 for improving its adhesion and then gold, for example, is deposited in a thickness of 1mum on the thin chromium film from an electrochemical stability's point of view.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an ink recording head that utilizes the electroosmotic phenomenon of liquid ink.

A depressed groove is provided on the surface of the dielectric substrate, a first electrode serving as a recording electrode is installed in the depressed groove, and a film or layered film having a two-dimensional spread is formed on the surface of the dielectric substrate having the depressed groove. An electroosmotic ink recording head in which a porous body is installed and a liquid ink permeable second electrode is installed on the opposite side of the porous body to the first electrode has already been proposed by one of the inventors of the present invention. Proposed.

This ink recording head supplies and impregnates the porous body with liquid ink, and applies a signal voltage between the first and second electrodes to cause the liquid ink to electroosmote through the porous body. By extruding with an on-voltage signal and attracting with an off-voltage signal through the depressed groove gap located between the electrode and the porous body, recording is made on the first electrode tip side in correspondence with the signal voltage. An ink image recording device for figures, symbols, etc. can be realized by forming a controlled liquid ink portion to be recorded on paper, and directly transferring it to the recording paper or causing it to fly and adhere to the recording paper using Coulomb force.

However, it has been found that this type of ink recording head requires special consideration for its material because it has the effect of pushing out and sucking liquid ink through the first electrode surface.

That is, in the conventional ink recording head described above, a conductive paint in which graphite or rice grains were mixed in a binder made of plastic material was used as the first electrode material. A part of the recorded liquid ink enters the inside of the first electrode and is impregnated therein, and also remains attached to the surface of the first electrode, so that when an off voltage signal is applied, these liquid inks are completely absorbed. It has been found that this impregnated residual ink adheres to the recording paper despite the application of an off-voltage signal, resulting in so-called tailing of the ink recording, resulting in a decrease in the resolution and quality of the recorded image.

The present invention aims to provide an improved ink recording head in view of the above problems.

The present invention will be explained more specifically. In the electroosmotic ink recording head described above, the first electrode is formed of a metal film deposited in the recessed groove by metal vapor deposition, plating, or the like. The aspects will be explained in detail.

The figure is a diagram showing an actual example of an electroosmotic ink recording head according to the present invention, a perspective partial structural view and a power supply system of an ink recording apparatus according to its application. The ink 6e is stored in the container 300 and uses the capillary action of the sponge body 700.
E≠Liquid ink supplied to and immersed in Heno 1 100.

400 is a signal voltage source, 500 is a recording note such as Ml which is a recording body, and 600 is a recording body 500 which is an ink recording head 1.
A contact roller 1 is made of rubber or the like and presses against the edge 13 and side edge end surface 12 of the paper and feeds the paper in the direction of arrow 507 in the figure.

1o is a support substrate made of a plate-shaped dielectric substrate such as borosilicate glass. The surface is etched or machined at a density of, for example, 3 to 8 per 1 B depending on the desired recording resolution.
Depending on the technique, for example, a depressed groove 16 having a width and depth of approximately 2 to 70 μm is provided. A first electrode 2o made of L tono-C1 metal film is formed on the bottom and sidewall of this groove 16.
is deposited jL 5 .

The first electrode 20 is coated with chrome etc. in advance, for example, o, i~0.
．． Preliminarily deposit the gold to a thickness of about 3 pm to improve the deposition %'k, and then deposit gold to a thickness of about 11 tm + i from the point of view of drowsiness chemical stability 1'J- in step 3. The roam film is plated with gold or the like to form a non-porous metal electrode film.

Thus, on this supporting substrate surface 11F, a porous body 4° having holes or gaps substantially penetrating in the thickness direction and through which the liquid ink 2o○ can permeate in the thickness direction is installed. A groove gap of 3° is formed between the groove and the surface of the electrode 20. porous body 4
For example, a so-called microporous membrane filter made of cellulose acetate having a thickness of 20 to 200 pm, an average pore diameter of 0.1 to 8 .mu.m, and a porosity of about 60 to 80% is used. Porous body 40. ! For :l-, other plastic materials, glass, porcelain materials, etc. can be used.

It is desirable that the edge 41 of the porous body 4o be located on the direction change side of, for example, 60 to 3001 t mg from the edge 13 of the support substrate 1o, so that an exposed edge surface 14 is formed on the support surface 111. To form the edge portion 14, this 14F
The electrical convergence effect of the liquid ink 200 using the electroosmotic property can be utilized, which is useful for high-resolution recording.

The porous body 40 is provided with pores (not shown) having a thickness of 50 to 300 pores (not shown) penetrating through it at a density of about 10 to 300 meters per inch, for example, on the inlet side of the countermoon that benefits the support substrate 1o of the porous body 40.
, a second J′) electrode 6o made of a stainless steel plate, metal mesh/L, etc. that is permeable to liquid ink 200 of about #m is installed,
The porous body 4o is pressed and fixed.

Note that the second electrode 5o may be constructed by applying a thin layer of conductive paint such as graphite to the porous body 403.

Setting up the recording body 500 of the porous body 4o It is sealed on the surface of the first electrode 20 to prevent backflow of liquid ink during electroosmosis during sewing.

The liquid ink 2o○ is supplied to the porous body 40 via the sponge body 7oo and the second electrode 6o, and is immersed therein.

The liquid ink 200 is applied to the porous body 40 described above. Support substrate 1
For example, an oil-soluble dye or the like can be added to a liquid material consisting of γ-methacryloxypropyltrimethoxine or the like, along with necessary binders, charge control agents, 2 surfactants, etc., to give good electroosmotic properties to 0. 2~ in weight ratio
The oil-soluble ink 200 is constituted by mixing about 6 pieces of concubine.

This type of ink electro-osmoses into the above-mentioned porous body 4o and support 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 to an electric field strength of about 2 V/μm in consideration of dielectric breakdown. First electrode 20 as a recording electrode
are connected to a signal voltage source 400, and the signal voltages VB,
VB t is selectively applied between the voltage and the second electrode 6o.

Now, as shown in the figure, the signal voltage is an off-voltage VBt at which the second electrode 6o becomes negative due to the first voltage □□□O.

On the contrary, the on-voltage VB of the electrode 20 is negative with respect to the electrode 50.
The operation will be explained by taking as an example the case in which the voltages are applied alternately.

In the part where VBt is applied, the liquid ink 200 flows in the direction of arrow 2 from the first electrode 20 side forming the positive electrode to the second electrode 60 side forming the negative electrode via the porous body 4o.
10, the liquid ink 200 located on the electrode tip 21 side also undergoes electroosmosis Cζ, as shown by the arrow 21 in the figure.
1, it is sucked up to the second electrode 50 side via the groove IQ 30.

Furthermore, since the support substrate 10 is also configured to have the same electroosmotic property as the porous body 4o, a negative electrode is formed by applying VBt; mark 7Jl] from the electrode 2o to which VB/ is applied. At adjacent electrodes 20 (khl, ), liquid ink 200 electroosmoses in the direction of arrow 212 over support surface 11 including electrode gap surface 16 .

Therefore, liquid ink 200 cannot exist on the tip 21 side of the first electrode 20 to which VB t is applied and the exposed edge surface 14 around it. 20 part-C is transmitted through the second electrode 50,
The liquid ink 200 is electroosmotic through the porous body 40 as shown by the arrow 220.

and concentrate toward the surface of the first electrode 2o. edge 13
Since the opposite end side is sealed with the sealing agent 60, the liquid ink 200 flows through the surface of the first electrode 20, that is, the groove gap 30, due to its electroosmotic pressure, and As shown by an arrow 221, a liquid ink portion 222 is formed on the exposed edge surface 14 side corresponding to the electrode 20 and whose ink amount is controlled with respect to the position control and 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, forming the depressed groove 1.
The formation of the liquid ink portion 222 becomes more effective due to the extrusion convergence effect to collect on the surface of the electrode 20 within the ink portion 6 .

In order to effectively utilize the suction, extrusion, and convergence effects of the liquid ink 200 as in the present principle, the edges 41 and 13 should be kept parallel in order to maintain a constant distance between the edges 41 and 13. is desirable, and if the interval, that is, the width of the exposed edge surface 14 is too narrow, the convergence effect of the liquid ink 200 on the surface 14 will be reduced and the recording resolution will be lowered, and if it is too wide, the VB
/1° at the time of application, the ink 200 on the tip 21 that should be suctioned remains without being completely suctioned, degrading the quality of the recorded image. From the above, the width of the web is selected as described above (approximately 50 to 300 μm).

A recording paper having a thickness of about so pm is used as the recording medium 500. For example, the off-voltage V B t has a constant amplitude of 16 ov, and the on-voltage VB has a maximum amplitude with the opposite polarity to V B t. 160v, amplitude modulation within this range according to the recording density, )(lus width modulation, ・(lus width amplitude modulation,
Depending on the voltage value, a liquid ink portion 222 with a controlled amount of ink is generated on the electrode tip 21 to which VB is applied, and ink adhesion 240 is generated on the surface of the recording medium 6ω due to contact transfer, while the electrode marked with vBl The tip part 21 has a liquid ink part 2.
22 cannot exist, so ink adhesion 240 does not occur.

Ink images can be recorded in accordance with the signal voltages VB and VB/ applied in this manner.

However, the conventional ink recording head 100-C uses a conductive paint in which conductive particles such as graphite or silver are mixed into a dielectric material such as a plastic material as the material of the first electrode 2o. Therefore, when the applied conductive paint dries and hardens, the first electrode 2o becomes porous due to the evaporation effect of the solvent and gas and the shrinkage effect of the binder, and the surface thereof becomes microscopically uneven. From a physical standpoint, it formed a rough surface.

Therefore, when the on-voltage vB is applied, a part of the ink of the recording liquid ink portion 222 formed at the tip 21 of the first electrode 2o may penetrate into the inside of the first electrode 2o and become impregnated, or may adhere to the rough surface. It is difficult to completely suck this ink when the off-voltage vBl is applied, and it remains as it is, impregnating and adhering to the electrode tip 21.

Therefore, despite the application of the off-voltage VB, the above-mentioned impregnated and residual ink is transferred and adhered to the recording medium 500.
The so-called ink trailing phenomenon causes a decrease in the resolution and quality of recorded images.

However, according to the present invention, the first electrode 2o is connected to the recessed groove 16.
By vapor deposition or plating, a non-porous, glossy mirror surface with few irregularities is formed on the bottom and side walls of the metal film, which prevents the above-mentioned ink impregnation and surface residue, and provides a sharp, sharp surface. There is an advantage that a high quality SLT6 resolution ink recording head can be realized.

In this embodiment, an application recording apparatus using a direct transfer method is used as an example.
An auxiliary electrode is installed on the opposite side of the head 100 to be burned at a distance of about μm, and between the electrode 20.50 of the first to a2 and this auxiliary electrode IC1, 5 to 2. By applying a DC voltage of approximately OKV, flight recording can be performed using Coulomb force1.In addition, in this case, the liquid ink portion 222 flows around from the electrode tip 21 to the side of the edge 12, causing unstable operation. In order to prevent this, this portion 12 can be made substantially ink repellent by applying an ink repellent agent to the surface of the side edge end surface 12. M/ζ, signal voltage VB,
In response to the increase in the frequency of VBt, in order to improve the quality deterioration of the recorded image due to the decrease in the convergence effect of the liquid ink 200 on the support base material surface 11, such as the mandrel gap 16, the inside of the support base material surface 11 is .

3. At least the electrode gap 16 of the exposed edge surface 14 can be provided with substantially ink repellency equivalent to applying an ink repellent agent. Further, the support substrate 10 itself can be made of an ink-repellent dielectric material.

The various configurations described above can be implemented in appropriate combinations.

As described above in detail, the ink recording head according to the present invention is an electroosmotic recording head in which the first electrode provided in the recessed groove of the support substrate is substantially composed of a metal film, and the first electrode Unnecessary impregnation and residue of liquid ink at the tip are prevented, and the quality and resolution of ink-recorded images are improved, and the industrial effect is extremely large.

[Brief explanation of drawings]

The figure is a diagram showing an embodiment of an electroosmotic ink recording head according to the present invention, and a perspective partial structure and power supply system of an ink recording apparatus to which the electroosmotic ink recording head is applied. 1o...Supporting substrate made of dielectric base material, 16...
... Depression groove, 20 ... First electrode, 30.
...Groove gap, 40...Porous body, 6o...
・Second electrode, 100... Ink recording head, 2
00...Liquid ink, 300...Ink container, 400...Signal voltage source, SOO...
Recording body, 600... Pressure roller, 700...
... Sponge body.

Claims (1)

[Claims] A depressed groove is provided on the surface of the dielectric base material, a first electrode is installed in the depressed groove, a porous body is installed on the surface of the dielectric base material having the depressed groove, and the first electrode of the porous body is provided with a depressed groove. In an electroosmotic ink recording head in which a liquid ink-permeable second electrode is installed on the opposite side to the first electrode,
An electroosmotic ink recording head characterized in that the electrodes are formed of a metal film.