JPH11157079A - Ink jet recorder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize good recording with high resolution by preventing clogging of ink near an ink discharge slot and avoiding a damage of an ink guide. SOLUTION: A recording medium is recorded by flying an ink droplet 8 of an ink 1 obtained by dispersing a colorant component in a solvent by operating an electrostatic force at the ink 1 toward the medium. A recording head is constituted by an ink guide 10 having a slit formed to elevate the ink by utilizing a capillarity and flat surfaces 15 formed oppositely to the medium at both sides of the slit 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus which performs recording by flying a liquid ink in which a colorant is dispersed in a solvent as ink droplets, and more particularly to a recording head provided with an ink guide. The present invention relates to an ink jet recording apparatus that generates electrostatic force by applying a voltage to a conductive member to eject ink droplets.

[0002]

2. Description of the Related Art A recording ink is formed by flying a liquid ink on a recording medium as minute droplets called ink droplets.
A recording apparatus that records an image by forming an image has been put to practical use as an inkjet printer. This ink-jet printer has the advantage that it has less noise than a mechanical recording device such as a wire dot printer, and does not require processing such as development and fixing as compared with an electrophotographic recording device such as the Carlson method. It has attracted attention as a plain paper recording technology.

Various types of ink-jet printers have been proposed so far. Typical methods include (a) discharging and flying ink droplets by the pressure of steam generated by the heat of a heating element. A piezoelectric method in which ink droplets are ejected by a mechanical pressure pulse generated by a piezoelectric element (for example, see Japanese Patent Publication No. 56-9429 and Japanese Patent Publication No. 61-59911). (Special Publication 53-1
No. 2138).

A recording head used in an ink-jet printer is mounted on a carriage and moves in a direction (hereinafter, referred to as a main scanning direction) orthogonal to a recording paper conveyance direction (hereinafter, referred to as a sub-scanning direction). Serial scanning heads for recording have been put to practical use. Since the serial scanning head cannot perform recording unless it is always moved by a predetermined amount in the main scanning direction, it is difficult to increase the recording speed. Therefore, a line scanning type printer in which the recording speed is increased by using a long head in which the length of the recording head is set substantially equal to the width of the recording paper has been considered. The realization is
It is not easy for the following reasons.

[0005] In the ink jet recording system, a large number of individual fine nozzles corresponding to the resolution are provided. However, evaporation or volatilization of a solvent is liable to cause local concentration of ink, which is a cause of clogging of the nozzles. Cause. Further, in the method of using the pressure of steam for forming an ink jet, the adhesion of unnecessary substances formed by reacting with the ink thermally or chemically induces nozzle clogging, and the pressure by a piezoelectric element is used. In the system, a complicated structure such as an ink flow path makes it easier to induce nozzle clogging. Even a serial scanning head using several tens to hundreds of tens of nozzles can cause nozzle clogging, but a line scanning head using many thousands of nozzles In
Further, it has been proved stochastically that the nozzles are clogged with a higher frequency of occurrence, and there is a problem that practical reliability is lacking.

Further, in the method using the pressure of steam, it is difficult to generate ink droplets having a diameter of 20 μm or less corresponding to recording dots having a diameter of about 50 μm on a recording paper. Is difficult to manufacture. Further, in the method using the pressure by the piezoelectric element, the structure of the recording head is complicated, so that it is also difficult to manufacture a high-resolution head due to a problem in processing technology. For this reason, in the conventional ink jet recording apparatus, there is a problem that it is difficult to improve the resolution in any method.

In order to solve these problems, a voltage is applied to an electrode array formed by arranging a plurality of individual electrodes formed of thin films on a substrate, and ink or ink is discharged from the ink liquid surface using electrostatic force. There has been proposed an ink jet recording method in which a colorant component in the ink composition is made to fly as an ink droplet.

More specifically, a method of flying ink droplets using electrostatic attraction (Japanese Patent Application Laid-Open Nos. 49-62024 and 56-62024)
Japanese Patent Application Laid-Open No. 7-502218) and a method in which the concentration of a coloring material is increased by using an ink containing a charged coloring material component to fly ink droplets (see Japanese Patent Application Laid-Open No. 7-502218). In these systems, the recording head has a slit-shaped nozzle structure that does not require a nozzle for each individual dot,
Alternatively, because of the nozzleless structure that does not require a partition of the ink flow path for each individual dot, it is effective for preventing and recovering from clogging of ink, which has been a major obstacle in realizing a line scanning recording head. is there. In the latter method of increasing the colorant concentration, ink droplets having a very small particle diameter can be stably generated and fly, so that the method is suitable for high resolution.

However, in the ink jet recording apparatus of the type in which the colorant component is ejected as ink droplets by the above-mentioned electrostatic force, the distance between the recording medium and the recording electrode is reduced because the force for causing the ink droplets to fly is electrostatic force. If it is not reduced to some extent, the electric field contrast between the adjacent electrodes is reduced, and a stable image cannot be recorded.
Although the diameter of the flying ink droplet is small, it is difficult to produce a recording head having a fine electrode pitch and high resolution, and practically, the limit is about 2 electrodes / mm. When making such a recording head high resolution,
The distance from the recording medium must be reduced to several hundred μm.

In order to solve such a problem, the present inventor has proposed an ink jet recording apparatus as shown in FIGS. FIG. 19 is a side view showing the recording head, and FIG. 20 is a perspective view showing the recording head. In FIG. 19, an insulating control substrate 3 is placed on an ink chamber 2 to which an ink 1 in which a colorant component is dispersed in a solvent is supplied. 4 are drilled. A control electrode 5 to which a voltage can be individually applied is provided on the periphery of the ink ejection hole 4.
Is supplied with a recording signal voltage Va from a recording signal voltage source 6 and a bias voltage Vb from a bias voltage source 7.

An ink guide 10A is provided for guiding the ink 1 from the ink chamber 2 to the ink ejection hole 4. This ink guide 10A has a rod-shaped base 11,
A protruding portion 12 protruding from the base 11 in the direction of the control board 3
And a slit 13 is formed at the center of the protruding portion 12, and the tip thereof is an inclined surface 14 which is inclined downward from the slit 13 to the side wall. Ink guide 1
Reference numeral 0A is made of an insulating resin, and is formed in a state of being connected in a line at the same pitch as the ink ejection holes 4 formed in the control electrode 5. When the recording voltage Va from the voltage source 6 is applied to the control electrode 5 from which ink is to be ejected in such a manner that the recording voltage Va is superimposed on the bias voltage Vb from the voltage source 7, the capillary 13 projects in the slit 13 by capillary force. The ink that has risen to the tip of 12 is ejected as an ink droplet 8 by the electric field between the control electrode 5 and the grounded counter electrode 17, and is printed on the recording paper 18 in contact with the counter electrode 17. Is formed.

Since the recording paper 18 moves relative to the ink guide 10A as indicated by the arrow in FIG. 19, the recording paper 18 is continuously applied by selectively applying the recording signal Va in accordance with the image signal. An image is formed. Since the ink guide 10A has the protruding portion 12, the ink discharge point is stabilized, so that a clear and stable image can be recorded.
Further, since a plurality of recording heads having such a structure can be continuously formed on the same plane, high resolution of the head can be easily realized by arranging the control electrodes 5 in a staggered manner. .

[0013] However, the above-mentioned conventional ink jet recording apparatus has a large hole as compared with other ink jet recording methods, but has a structure in which ink is ejected from the ink ejection hole 4 again. For example, if the ink 1 is not completely removed from the periphery of the ink ejection hole 4, clogging of the hole may occur. As a problem peculiar to the ink-jet recording apparatus, measures for solving the clogging have been considered for a long time. For the problem of clogging, countermeasures such as capping, wiping, and sucking ink have been conventionally taken.
The clogging has been greatly reduced, and the clogged head can be recovered.

[0014]

However, since the above-described ink guide 10A is made of resin and has a structure that fits within a hole diameter of about 200 μm,
The tip of the projection 12 is very fine and soft. Therefore, if a measure against clogging as conventionally performed is taken, the possibility that the protruding portion 12 is damaged is increased. In particular, wiping that rubs the head surface is completely impossible. Further, the adhesion of the ink to the protruding portion 12 occurs even when continuous recording is performed for a long time,
In some cases, the ink ejection characteristics change. Also,
Once the protruding portion 12 has dried, there is a problem that the ink does not reach the tip even if the ink is to be blown out next time. Even in such a case, it is difficult for the conventional inkjet recording apparatus to return the head. Further, when a paper jam occurs and the paper bends near the head or collides with the head, there is a problem that the protrusion 12 is damaged.
As described above, the use of the ink guy 10A having the protruding portion 12 has caused some new problems.

In order to solve the above problem, the present invention provides an ink jet recording apparatus which can prevent ink clogging in the vicinity of an ink ejection hole, avoid damage to an ink guide, and perform high-resolution and good recording. It is intended to provide.

[0016]

According to a first aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink in which a colorant component is dispersed in a solvent; In an ink jet recording apparatus that performs recording on a recording medium by flying ink droplets containing the ink toward a recording medium, a slit formed to suck up the ink by utilizing a capillary phenomenon, and the recording is performed on both sides of the slit. An ink guide having a flat surface formed so as to face the medium is provided.

According to a second aspect of the present invention, there is provided an ink jet recording apparatus according to the first aspect, wherein the ink guide projects from the base in the direction of the recording medium and extends along the center line. And a protrusion formed with the slit, wherein the flat surface is formed at a tip of the protrusion.

Further, according to a third aspect of the present invention, in the ink jet recording apparatus according to the second aspect, the projecting portion is formed by an ink ejection hole formed in an insulating substrate provided to face the recording medium. At the periphery of the ink ejection hole, a control electrode to which a pulse voltage is applied to cause the ink sucked up by the capillary phenomenon to fly as an ink droplet by electrostatic force to the recording medium at the periphery of the ink ejection hole is provided. It is characterized by being provided.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the second aspect, at least the protrusion of the ink guide is formed of a conductive material. Is supplied with a pulse voltage for causing the ink sucked up by the capillary phenomenon to fly through the slit as an ink droplet by electrostatic force to the recording medium.

Further, in the ink jet recording apparatus according to a fifth aspect of the present invention, in the ink jet recording apparatus according to the third or fourth aspect, both ends of the ink guide are obliquely cut to form an inclined surface. Are characterized in that the flat surfaces are left on both sides of the.

According to a sixth aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the ink guide is formed in a flat base and a groove formed at a predetermined distance from an end surface of the base. And a conductive protrusion implanted on the recording medium, wherein the surface of the protrusion facing the recording medium at the tip end surface is the flat surface, and the slit is formed so as to divide the flat surface. Features.

Further, in the ink jet recording apparatus according to claim 7, in the ink jet recording apparatus according to claim 6, both ends of the projecting portion of the ink guide are cut obliquely to form an inclined surface, and both sides of the slit are formed. Is characterized in that the flat surface is left.

According to an eighth aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the ink guide is formed in a flat base and a groove formed at a predetermined distance from an end surface of the base. And a conductive portion embedded in the conductive member, wherein the conductive portion is connected to a voltage supply source for supplying a pulse voltage of the recording signal.

According to a ninth aspect of the present invention, in the ink jet recording apparatus according to the first aspect, the ink guide has a flat base, a slit formed on the base at predetermined intervals, and And a conductive portion attached to both sides of the flat plate portion, the conductive portion being connected to a voltage supply source for supplying a pulse voltage of a recording signal.

According to a tenth aspect of the present invention, in the ink jet recording apparatus according to the eighth or ninth aspect, the flat surface is left on both sides of the slit, and V is formed on both sides of the flat surface. It is characterized in that a pair of letter-shaped cut portions are formed.

As described above, the present invention is characterized in that the tip portion from which ink is ejected has a flat portion instead of a sharp structure as in the related art. More specifically,
The ink guide to be inserted into the control electrode provided with the ink ejection holes as in the related art is configured to have a flat surface only at the foremost portion, even in the case of a structure tapering toward the tip. In addition, the protrusion shape of the ink guide is not made to have a structure that becomes thinner as it goes forward. In this case, the front end of the ink guide has a flat structure regardless of the configuration.

In addition to the configuration in which a control electrode is provided and a voltage is applied to the control electrode, the present inventor has already proposed an ink jet recording apparatus for forming an image by directly applying a recording voltage to a projection of an ink guide. ing. Even in such a configuration, the gist of the present invention is to form a flat portion at a position where the ink droplet at the tip of the ink guide is formed and flies. When applying a voltage directly, a slit is formed on a flat substrate to carry ink to the front end of the substrate by capillary force without forming a protruding structure, and an electrode for applying a voltage is formed around this slit. There is also a configuration to do so. With this configuration, the ink guide has no protruding portion, and the tip of the head is completely flat. Further, when a voltage is directly applied, a projection structure may be formed only around the slit, and all other portions may be formed as flat surfaces.

With each of these configurations, since a flat surface is provided at least at the ink droplet flying position at the tip of the ink guide, it is possible to improve points that are weak against rubbing or the like. Thus, even if the tip of the head is rubbed by wiping or the like which has been conventionally performed as a measure against clogging, the shape of the head is not changed. Even if a capping or suction device is used, it is possible to handle the projection without paying much attention to the tip of the projection. In addition, even when the colorant adheres to the projections after long use, by cleaning the projections at the start of recording, it is possible to easily restore a beautiful state and start recording stably. . Further, even when a paper jam is detected, the protrusion is not to be sharpened and is strong, so that damage to the protrusion can be prevented.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the ink jet recording apparatus according to the present invention will be described in detail with reference to the accompanying drawings. 1 and 2 are a cross-sectional view and a perspective view, respectively, showing a main part near the head of the ink jet recording apparatus according to the first embodiment. In the figure, the components denoted by the same reference numerals as those in FIGS. 19 and 20 showing the conventional ink jet recording apparatus denote the same or corresponding components, and a description thereof will be omitted.

In FIG. 1 and FIG. 2, the upper part of the ink chamber 2 in which the ink 1 is stored is closed by an insulating control substrate 3. The control substrate 3 is provided with an ink discharge hole 4, and a control electrode 5 is provided on the periphery of the ink discharge hole 4. The protrusion 12 of the ink guide 10 protrudes from the ink ejection hole 4, and the protrusion 1 of the ink guide 10, which is a resin protrusion insulated through the ink protrusion hole 4.
2 protrudes from the surface of the control electrode 10 in the direction in which the ink is ejected. The bias voltage Vb is constantly applied to the control electrode 10, and the signal voltage Va is superimposed on the control image in accordance with the recorded image. The liquid ink 1 in the ink chamber 2 is in a state where the bias voltage Vb is applied.
The surface of the ink guide 10 is wetted thinly, and is crawling up the slit 13 formed in the ink guide 10. When a signal voltage Va is applied, the recording paper placed opposite to the recording paper is placed from the tip of the ink guide 10. Ink drop 8
Flies and forms a dot on the recording paper.

A feature of the first embodiment is that, as shown in FIG. 1, the tip of the ink guide 10 is not sharp as shown in FIGS. Is formed with a flat surface 15. Normally, the ink guide 10 is made of resin, and the dimensions of the protruding portion are about 300 to 400 μm in length, about 20 μm in width, the width of the slit 13 is about 40 to 60 μm, and the thickness is about 100 μm, It is formed by processing a polyethersulfone or polyimide film precisely with a laser. With such a fine structure, the resin is also very soft, and even if the tip is slightly touched, the tip is bent and the slit is narrowed or widened.

In such a situation, the amount of ink and the ejection voltage ejected from each projection 12 are different, and the ejection direction is also changed, so that the quality of the recorded image is significantly deteriorated. As in the first embodiment, by flattening the tips of the protrusions of the ink guide, the strength of the protrusions is increased, and the phenomenon that the protrusions are deformed by a small force is suppressed.

Ink ejection hole 4 formed in control board 3
Has a diameter of several 100 μm, so nozzle clogging is less than that of a general inkjet printer. However, if the nozzle is not used for a long time, ink clogging occurs. In general inkjet printers, it is possible to deal with physical methods such as absorbing ink and wiping off attached ink.
19 and 20, since the ink guide 12 is formed of a soft resin, it is difficult to prevent the ink from being clogged by such a physical method. .

However, as in the ink jet recording apparatus according to the first embodiment shown in FIG. 1, the protruding portion 12 of the ink guide 10 has a flat surface 15 so that the protruding portion 12 of the ink guide 10 is hardly damaged. So you can
It becomes possible to take measures against physical clogging. Specifically, when the cleaning is performed by directly rubbing the protruding portion 12 with a wiper made of soft bristles such as a brush, or when suction is performed by a suction device such as a vacuum pump, This can be realized with a simple device without paying attention to deformation. Furthermore, even if a paper jam occurs and the paper touches the tip of the projection, deformation of the tip of the projection is prevented unless the tip of the projection is rubbed with a very large force.

FIG. 1 shows an example in which the bias voltage Vb and the signal voltage Va are applied to the control electrode in a superimposed manner. However, the reverse bias voltage -Vb is applied to the recording paper side, and the signal is applied to the control electrode. The same effect can be obtained by simply applying the voltage Va. As a method of applying the reverse bias voltage -Vb to the recording paper side, an electrode to which a voltage of -Vb is applied is provided on the back side of the recording paper, or an insulator charged to -Vb by a charger is provided on the back side of the recording paper. It can be realized even if it is configured to be provided.

Although it is shown that only the ink 1 exists in the ink chamber 2, the ink chamber 2 may be filled with a fiber, a porous body, or the like. In the case of ink 1 only, a mechanism to keep the ink surface constant at all times is required, but in the case of a porous body or fiber inside, the ink is supplied by the amount used by the capillary force. Therefore, the state of ink ejection can always be kept constant without a liquid level maintaining mechanism.

It should be noted that the present invention is based on Japanese Patent Application No.
In combination with the invention of -51451, the effect is further enhanced. The invention of this patent application has a configuration in which the ink guide is reciprocated from the ink ejection hole to perform recording by projecting the ink guide from the ink ejection hole at the time of recording, and to house the ink guide in the ink chamber at the time of non-recording. I have. As described above, the relative position of the ink guide 10 with respect to the control board 3 is changed, and when recording is performed, the ink guide 10 is installed at a position where the tip of the protruding portion 12 projects from the control electrode 3 toward the recording paper. The position of the ink guide is moved so that the tip of the protruding portion 12 is lower than the control board 3.

When the protrusion is immersed in the ink, the coloring material of the ink adhering to the projection is immersed in the solvent again, so that the coloring material dissolves in the solvent and the tip of the ink guide is cleaned. That is, the effect of the cleaning is greater than when each invention is individually implemented. In this case, it is necessary to move the ink guide 10 in and out of the ink ejection hole 4 formed in the control electrode 3. Here, when the tip of the projection is sharp as shown in FIGS. 19 and 20, even if the tip of the projection 12 touches the edge of the ink ejection hole 4 even a little, the tip of the projection 12 is deformed. Would be. As in the present invention, the protrusion 1
In the case where the tip of the projection 2 is set as the flat surface 15, even when the tip of the projection 12 touches the edge of the ejection hole 4 when the ink guide 10 is moved up and down, the tip of the projection is less likely to be deformed.

Next, an ink jet recording apparatus according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 3 shows a second embodiment of the ink guide 10 having a flat surface 15 at the tip of the protrusion 12 shown in FIG. The ink guide in FIGS. 1 and 2 was an insulator formed of a resin such as polyethersulfone or polyimide. On the other hand, in the ink guide according to the second embodiment shown in FIGS. 3 and 4, of the tip portions of the protruding portions 12A and 12B, a portion indicated by satin is made of a conductor such as metal. . Such an ink guide can be made by laser processing a resin to form an ink guide as shown in FIGS. 1 and 2, and then depositing metal only on necessary portions by vapor deposition or plating. It is possible. 2 and 3, the insulating substrate 3, the control electrode 4, and the like are omitted.

In the case of the ink guide 10 shown in FIG. 3, it can also be formed by etching a metal foil into a shape of a protrusion and then forming a lower resin portion. By making the protrusions 12A and 12B of the ink guide 10 a conductor, the electric field at the tip of the ink guide becomes large, so that ink is easily ejected, and the recording gap increases, the signal voltage decreases, the recording frequency increases, and the like. There are advantages. FIG. 3 shows an example in which the entirety of the protruding portion 12A is made conductive, and FIG. 4 shows an example in which a part of the protruding portion 12B is made conductive, and furthermore, the tip of the protruding portion 12B is insulated. is there.

A charged colorant is used for the ink, and the ink is ejected by applying a voltage having the same polarity as the charged colorant to the control electrode. In this recording method, the electric repulsive force acting between the control electrode and the charged colorant is a large force for ejecting ink. The repulsive force is a force for ejecting the ink, but also a force for moving the ink in a direction other than the original ejection direction. By further insulating the front end as shown in FIG. 4, the ink ejection direction can be further stabilized.

Next, an ink jet recording apparatus according to a third embodiment of the present invention will be described with reference to FIGS. The ink jet recording apparatus according to the third embodiment has a tapered shape like a projection 12 having an inclined surface 14 like the ink guide 10A of the conventional ink jet recording apparatus. However, a flat surface 15 is formed at the tip end of the protruding portions 12 and 12A. The width of the flat surface 15 is extremely small, about 5 to several tens of micrometers, but the strength of the tip greatly increases as compared with the conventional tip having a sharp tip. FIG. 5 shows an example in which the ink guide is made of resin, and the control electrode 4 is used as shown in FIG.
FIG. 6 shows an example in which the tip has a tapered shape and the tip of the protrusion 12A of the ink guide 10 is made conductive as shown in FIG. As a matter of course, as shown in FIG. 4, the leading end portion of the projecting portion 12A which is made into a conductor may be further insulated. 5 and 6, the ink chamber 2, the insulating substrate 3, the control electrode 4, and the like are omitted.

Next, an ink jet recording apparatus according to a fourth embodiment of the present invention will be described with reference to FIGS. In the ink jet recording apparatuses according to the above-described first to third embodiments, the ink guide 10 is basically insulated and located in the vicinity of the ink guide, although there is an example in which a part is made conductive. A voltage was applied to the control electrode to eject ink. On the other hand, in the fourth embodiment, a voltage is directly applied to the conductive ink guide without using the control electrode to eject ink. FIG. 7 is a sectional view showing a main part of an ink jet recording apparatus according to the fourth embodiment, and FIG. 8 is a perspective view thereof.

In FIG. 7, the protrusion 22 of the ink guide 20 has substantially the same shape as the protrusion 12 of the first embodiment shown in FIG. That is, the ink guide 20
Comprises an insulating base 21 and a protruding portion 22 implanted in the base 21, and the tip of the protruding portion 22 is
Protrudes from the ink ejection hole 4 toward the recording medium. A slit 23 and a flat surface 25 are formed at the tip of the protruding portion 22, and the entire protruding portion 22 is formed of a conductor. The signal voltage source 6 and the bias voltage source 7 are connected to the conductive protrusion 22.

In the first embodiment shown in FIG. 1, the control substrate 3 on which the control electrode 5 is formed is used. On the other hand, in the case of the substrate 3 in the fourth embodiment, ink is simply discharged. Only the holes 4 are formed, and only the ink is functionally retained. Instead, the protruding portions 22 of the ink guide 20 are each made into a conductor by vapor-depositing or plating a metal, and the protruding portions 22 each made into a conductor are further provided with a bias voltage Vb.
And the recording signal voltage Va are superimposed and applied.

The ink 1 which has risen in the slit 23 by the capillary force becomes an ink droplet 8 by the bias voltage Vb and the signal voltage Va directly applied to the protruding portion 22 of the ink guide 20, and flies on the recording paper. go. When a voltage is directly applied to the protrusion 22 of the ink guide 20 as compared with a case where a voltage is applied to the protrusion 12 via the control electrode, a large electric field acts on the ink. Therefore, it is possible to increase the recording frequency, decrease the recording voltage, and increase the ejection distance.

Next, an ink jet recording apparatus according to a fifth embodiment will be described. 9 and 10 show an ink jet recording apparatus according to a fifth embodiment in which a voltage is directly applied to the ink guide 20. When a voltage is directly applied to the ink guide 20, the function of the substrate 3 merely serves as a lid of an ink tank for holding ink, and is essentially unnecessary. In the fourth embodiment, the ink ejection holes 4 are formed in the substrate 3. However, in the fifth embodiment, the ejection holes are not formed in the substrate 3, but as shown in FIG. An opening groove 4A is formed.

FIGS. 10 (a) and 10 (b) are cross-sectional views of the perspective view of FIG. 9 taken along lines (a)-(a) and (b)-(b).
It is sectional drawing of (b). As is clear from the figure, the substrate 3
Is formed with a slit-shaped opening groove 4A instead of an ink ejection hole. Irrespective of the shape of the opening, the ink rises in the slit 23 formed in the ink guide by capillary force, so that when the recording signal voltage supplied from the signal voltage source 6 is applied, Ink can be ejected from the tip of the protrusion. A flat surface 25 is formed at the tip of the protrusion 22, and the protrusion 22 is attached to the base 21.

When comparing the hole-shaped ejection hole with the slit-shaped opening groove, the slit-shaped opening groove is more advantageous because the clogging of ink is considered. Conversely, considering the problem of ink retention, a hole-shaped ejection hole having a small opening is more advantageous than an opening groove, and a hole-shaped ejection hole is more preferable in consideration of a degree of freedom such as a direction in which a recording head is installed. Will be. Although FIGS. 9 and 10 show a state in which only the ink is filled in the ink tank, a porous ink holding member may be provided in the ink tank. By doing so, the problem relating to ink retention when the slit-shaped opening groove 4A is used is also improved.

Next, an ink jet recording apparatus according to a sixth embodiment, which is a modification in the case where a voltage is directly applied to the protrusion of the ink guide, will be described with reference to FIG. FIG. 11 is a perspective view illustrating a main part of an inkjet recording apparatus according to the sixth embodiment. In FIG. 11, the sixth
The ink jet recording apparatus according to the embodiment also has a control board 3
Is provided with a slit-shaped opening groove 4A, and further, the tip of the protruding portion 22 of the ink guide 20 has a tapered shape, and the flat surface 25 and the flat surface 25 sandwich the slit 23.
And an inclined surface 24 extending from the side wall to the side wall.

The protruding portion 22 is formed of a conductor, and the signal voltage source 6 and the bias voltage source 7 are connected to each other. Slit 23 at the tip of projection 22
Signal voltage Va applied to cause ink droplets to fly from a meniscus formed from
Is supplied from the signal voltage source 6. As described above, even if the inclined surface 24 is formed, the provision of the flat surface 25 makes it possible to form a meniscus well, to surely form an ink droplet, and to realize a high resolution.

In the ink jet recording apparatuses according to the first to sixth embodiments, each of the ink guides 10 and 20 is provided with the protruding portions 12 and 22, but the present invention is not limited to this. If the flat surface is provided on both sides of the slit of the ink guide where the meniscus is formed for discharging the ink droplet, the feature of the present invention is sufficiently provided. Hereinafter, an ink jet recording apparatus according to seventh to eleventh embodiments of the present invention including an ink guide having no protrusion will be described with reference to FIGS. 12 to 16. In these embodiments, all the ink ejection ports use slit-shaped nozzles instead of holes.

First, an ink jet recording apparatus according to a seventh embodiment of the present invention will be described with reference to FIG. The ink guide 30 in the ink jet recording apparatus according to the seventh embodiment is formed by forming a slit 33 in a plate-shaped resin substrate 31 by laser processing or the like, and plating or depositing metal near the slit 33 to form an electrode 32. Is created. By placing such a substrate 31 in the slit-shaped opening groove 4A of the control substrate 3 and applying a signal to each electrode, ink can be ejected from the tip of the slit 33. The ink rises in the slit 33 to the tip of the head due to the capillary force, and when a voltage is applied to the electrode 32, the ink droplet flies from the tip.

In the seventh embodiment shown in FIG.
Since the front end surface of the resin substrate 31 including No. 2 was completely flat and the protruding portion was completely eliminated, there was no problem even when a large physical force was applied to the head. Therefore, when the ink sticks, it is possible to perform cleaning by rubbing the tip with a blade or the like. Even if paper jam occurs, the tip of the head is not damaged at all.

In the ink jet recording apparatus according to the seventh embodiment, the front end surface protruding from the opening groove 4A of the resin substrate 31 is a completely flat surface except for the slit 33. FIG. As shown in the ink jet recording apparatus according to the eighth embodiment shown in FIG.
V-shaped notch 3 between the electrode and the flat surface 35 of the electrode 32
7 may be formed. Although not protruding from the end face 36 of the substrate 31 due to the cut groove 37, the tip of the electrode 32 has a tapered shape like the tip of the protruding portion 22 of the sixth embodiment shown in FIG.

The ink guide 30 according to the eighth embodiment
A indicates that the resin substrate 31 is formed on the most advanced surface 3 by laser processing or the like.
6, after forming a slit 33 and a cut groove 37 to form a protruding portion, a metal can be plated or vapor deposited near the slit. This 8th
Also in the embodiment, a flat surface 35 is provided at the tip of the protruding portion.
Are formed, and have the same height as the peripheral portion. Therefore, even if it is in the shape of a projection, it does not protrude from the periphery, and the tip of the projection is very strong. By adopting such a structure, the electric field is concentrated on the tip of the protruding portion as compared with the ink jet recording apparatus according to the seventh embodiment shown in FIG. 12, so that the ink is more easily ejected. There is also an effect. In addition,
When the tip of the protruding portion is sharp, a structure in which the tip of the protruding portion is lower than the peripheral portion does not damage the tip of the protruding portion.

Next, an ink jet recording apparatus according to a ninth embodiment of the present invention will be described with reference to FIG.
The ninth embodiment is a head basically having the same structure as that of the seventh embodiment shown in FIG. 12, and has a structure in which a portion from which ink is ejected does not protrude from a peripheral portion. In the seventh embodiment, the resin substrate 31 is processed to form a head, whereas in the ninth embodiment, a head such as a flexible substrate is used.
The difference is that a substrate 41 having a metal foil on both surfaces of a resin is used.

In FIG. 14, the ink guide 40 has a slit 43 formed on the front end surface 46 of the substrate 41, flat surfaces 45 located on both sides of the slit 43, and a slit 48 corresponding to the slit 43. And electrodes 42 provided on both side surfaces of the substrate 41. The electrode 42
It is connected to a signal voltage source 6 for supplying a recording signal voltage and a bias voltage source 7 for supplying a bias voltage.

The ink guide 40 having the above configuration has a thickness 50
A substrate 46 having about 18 μm thick copper on both sides of a polyimide resin of about 100 μm is first etched on both sides in the form of a desired electrode 42, and then a portion of the polyimide is formed to form a slit 48. Is formed by laser processing or etching. By doing so, the ink guide 40 as shown in FIG. 14 can be formed. When the ink guide 40 is formed by this method, a feature is that the head can be formed more easily than in the seventh embodiment shown in FIG. Since a flat surface 45 is provided at the tip end similarly to FIG. 12, it is strong against physical forces such as paper jam and cleaning.
In the structure as in the ninth embodiment, the electrode 4
2 is formed on both sides of the substrate 41, so that not only the same voltage can be applied to both electrodes to control the ink ejection but also a different voltage can be applied to control. ing.

FIG. 15 has flat surfaces 45 on both sides of the slit 43 at the tip of the ink guide 40A.
21 shows an ink jet recording apparatus according to a tenth embodiment in which an inclined portion 49 is formed at a tip of the ink jet recording apparatus and etched so as to be tapered. According to the tenth embodiment, by tapering the tip of the individual electrode 42, an electric field is concentrated on the tip, and a unique effect is obtained in that ink is easily ejected. In FIG. 15, a flat portion is also formed at the tip of the electrode 42, but the tip of the electrode 42 may be sharp. However, if the tip of the electrode 42 is sharpened,
Since variations in etching and the like are likely to occur, it is preferable to form a slightly flat portion at the tip of the electrode 42 as shown in FIG.

FIG. 16 is also a perspective view showing an ink jet recording apparatus according to an eleventh embodiment in which a double-sided board is processed and used as an ink guide 40B. The ink guide 40B according to the eleventh embodiment corresponds to the ink guide 30A according to the eighth embodiment shown in FIG. 13 except that the individual electrodes 42 have a plate shape. That is, although only the portion where ink is ejected is processed into a protruding shape by the cut groove 47, the level of the flat surface 45 at the tip of the protruding portion is the same height as the level of the front end surface 46 of the substrate 41. Has become.

As described above, by providing the cut groove 47 to separate the flat surface 45 and the front end surface 46, the amount of ink when forming a meniscus at the front end of the ink guide 40B can be made appropriate. This has an effect unique to the eleventh embodiment. In the ink jet recording apparatuses according to the above-described seventh to eleventh embodiments, the tip surfaces 36 and 46 of the substrate 31 and the point 41 are connected to the ink guides 30 and
Flat surfaces 35, 45 at the tips of 0A, 40, 40A, 40B
However, the present invention is not limited to this, and the level of the flat surface at the tip of the ink guide may be set to be lower than the level of the substrate.
As one example, there is an ink jet recording apparatus according to the twelfth embodiment shown in FIG.

In FIG. 17, the ink guide 50 according to the twelfth embodiment includes an individual electrode 52 having a flat surface 55 that is recessed from the front end surface 56 of the substrate 51. The individual electrode 52 is provided with a slit 53 for sucking up ink by utilizing a capillary phenomenon, and is formed of a conductor. A signal voltage source 6 for supplying a recording signal voltage Va and a bias voltage source 7 for constantly supplying a bias voltage Vb are connected to the individual electrodes 52, similarly to the electrodes 32 and 42 according to the previous embodiments. . As described above, even when the flat surface 55 of the electrode is lower than the front end surface 56 of the substrate via the step portion, the ink amount of the meniscus formed at the front end of the ink guide 50 can be optimized. Ink droplets can be formed satisfactorily, and the resolution during recording can be improved.

As shown in FIG. 17, when the tip of the electrode is lower than the peripheral portion, the tip of the electrode 52 having a low level flat surface may be tapered. FIG. 18 shows an ink jet recording apparatus according to the thirteenth embodiment including an ink guide 50A in which the electrode 52 is formed to have a tapered shape by the cutout portion 57, similarly to the eighth embodiment shown in FIG. In FIG. 18, the electrode 52
Is flattened with respect to the recording medium with respect to the front end surface 56 of the substrate 51, a slit 53 is formed in the flat surface 55, and a cut groove 57 is formed outside the electrode 52. Are formed.

According to the ink guide 50A of the ink jet recording apparatus according to the thirteenth embodiment having such a configuration, the front end of the ink guide can be protected by the front end surface 56 of the substrate 51, and the vicinity of the slit 53 of the electrode 52 can be protected. The meniscus can be formed with an appropriate amount of ink. As shown in FIG. 17, even if the flat surface 55 of the electrode 52 is simply retracted, the amount of ink forming a meniscus can be made an appropriate amount. However, as shown in FIG. This further improves the recording resolution.

It is to be noted that, unlike the ink guides 50 and 50A of the twelfth and thirteenth embodiments shown in FIGS. The present invention can be applied to an embodiment in which electrodes are formed only on both surfaces of the substrate, such as the ninth to eleventh embodiments shown in FIGS. Although illustration and detailed description are omitted, even if the configuration in which the flat surfaces on both sides of the slit are retracted from the front end surface of the substrate is applied to the embodiment in which the electrodes are formed on both surfaces of the substrate, the twelfth and thirteenth embodiments can be omitted. The same effect as the ink guide of the ink jet recording apparatus can be obtained.

[0067]

As described in detail above, according to the ink jet recording apparatus of the present invention, by providing a flat surface at the tip of the ink guide, the strength of the tip of the ink guide can be increased, and wiping and ink The tip of the ink guide can be protected against capping for preventing solidification, and there is an effect that good recording can be guaranteed.

Further, the tip is not damaged even if the ink guide is rubbed by wiping or the like, so that the life of the ink guide can be extended and high-resolution recording can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a main part of an inkjet recording apparatus according to a first embodiment.

FIG. 2 is a schematic perspective view showing an ink guide according to the first embodiment.

FIG. 3 is a perspective view showing an ink guide of an ink jet recording apparatus according to a second embodiment.

FIG. 4 is a perspective view showing a modification of the inkjet recording apparatus according to the second embodiment.

FIG. 5 is a perspective view illustrating an ink guide of an inkjet recording apparatus according to a third embodiment.

FIG. 6 is a perspective view showing a modification of the inkjet recording apparatus according to the third embodiment.

FIG. 7 is a sectional view showing a main part of an ink jet recording apparatus according to a fourth embodiment.

FIG. 8 is a perspective view showing an ink guide of an inkjet recording apparatus according to a fourth embodiment.

FIG. 9 is a perspective view illustrating an ink guide of an inkjet recording apparatus according to a fifth embodiment.

10 is a sectional view taken along line (a)-(a) of FIG. 9, and a sectional view taken along line (b)-(b) of FIG. 9;

FIG. 11 is a perspective view showing an ink guide according to a sixth embodiment.

FIG. 12 is a perspective view showing an ink guide according to a seventh embodiment.

FIG. 13 is a perspective view showing an ink guide according to an eighth embodiment.

FIG. 14 is a perspective view showing an ink guide according to a ninth embodiment.

FIG. 15 is a perspective view showing an ink guide according to a tenth embodiment.

FIG. 16 is a perspective view showing an ink guide according to an eleventh embodiment.

FIG. 17 is a perspective view showing an ink guide according to a twelfth embodiment.

FIG. 18 is a perspective view showing an ink guide according to a thirteenth embodiment.

FIG. 19 is a sectional view showing a conventional ink jet recording apparatus.

FIG. 20 is a perspective view showing the conventional ink jet recording apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid ink (meniscus) 2 Ink chamber 3 Insulating substrate 4 Ink ejection hole 5 Control electrode 10 Ink guide (recording head) 11 Base 12 Projection 13 Slit 14 Slope 15 Flat surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shuzo Hirahara 1 Komukai Toshiba-cho, Yuki-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba R & D Center (72) Inventor Hideyuki Nakao Yuki-ku, Kawasaki-shi, Kanagawa Komukai Toshiba 1 Toshiba R & D Center (72) Inventor Koichi Ishii 1 Komukai Toshibacho 1 Koyuki-ku, Kawasaki City, Kanagawa Prefecture Toshiba R & D Center (72) Inventor Yuko Nomura 1 Toshiba R & D Center, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa

Claims (10)

[Claims] An ink jet recording apparatus for recording on a recording medium by applying an electrostatic force to an ink in which a coloring agent component is dispersed in a solvent so that an ink droplet containing at least the coloring agent component flies toward the recording medium. In a recording apparatus, an ink guide having a slit formed to suck up the ink by using a capillary phenomenon, and a flat surface formed on both sides of the slit so as to face the recording medium is provided. Characteristic inkjet recording device. 2. The ink guide according to claim 1, wherein the ink guide includes a long base, and a protrusion protruding from the base in the direction of the recording medium and having the slit formed along a center line. 2. The ink jet recording apparatus according to claim 1, wherein the ink jet recording apparatus is formed at a tip of the protrusion. 3. The projection portion is provided so as to protrude from an ink ejection hole formed in an insulating substrate provided to face the recording medium, and absorbs ink sucked up by a capillary phenomenon through the slit. 3. The ink jet recording apparatus according to claim 2, wherein a control electrode to which a pulse voltage for causing the recording medium to fly as an ink droplet by electrostatic force is provided at a peripheral edge of the ink ejection hole. . 4. The ink guide, wherein at least the protruding portion is formed of a conductive material, and the ink sucked up by the capillary phenomenon through the slit is formed as an ink droplet by electrostatic force on the recording medium. 3. The ink jet recording apparatus according to claim 2, wherein a pulse voltage for flying is supplied to the conductive protrusion. 5. The ink guide according to claim 3, wherein both ends of the ink guide are cut obliquely to form an inclined surface, and the flat surface is left on both sides of the slit.
Or the inkjet recording device according to claim 4. 6. The ink guide includes a flat base, and a conductive protrusion implanted in a groove formed at a predetermined distance from an end surface of the base, and a tip of the protrusion. 2. The ink jet recording apparatus according to claim 1, wherein a surface of the surface facing the recording medium is the flat surface, and the slit is formed so as to divide the flat surface. 7. A protruding portion of said ink guide, wherein both sides of a tip portion thereof are cut obliquely to form an inclined surface, and said flat surface is left on both sides of said slit. 3. The ink jet recording apparatus according to claim 1. 8. The ink guide includes a flat base and a conductive portion buried in a groove formed at a predetermined distance from an end surface of the base, and the conductive portion includes a recording signal pulse. The inkjet recording apparatus according to claim 1, wherein the inkjet recording apparatus is connected to a voltage supply source that supplies a voltage. 9. The ink guide has a flat base, a slit formed in the base at a predetermined interval, and a conductive portion attached to both sides of the flat plate, having a slit corresponding to the slit. 2. The ink jet recording apparatus according to claim 1, wherein the conductive portion is connected to a voltage supply for supplying a pulse voltage of a recording signal. 10. The flat surface is left on both sides of the slit, and a pair of V-shaped cuts are formed on both sides of the flat surface. 10. The ink jet recording apparatus according to 9.