JP2000168102A - Ink-jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink-jet recording apparatus capable of preventing choking or adhesion of an ink so as to supply the ink stably with a homogeneous density to a head. SOLUTION: An ink-jet recording apparatus for recording an image by ejecting a liquid ink from the tip end of a head such as an ejecting electrode 2 comprises an ink case 3 disposed on the rear side of a heat tip end for storing an ink for supplying the ink to the head, a belt 4 disposed in the ink case 4, and a belt driving means for agitating the ink 5 in the ink case 3 by driving the belt 4. The belt driving means comprises a pulley 7 for hanging the belt 4 on, and a motor 6 for driving the pulley 7, wherein the drive of the motor 6 is controlled by a motor control part 11. By contacting the belt 4 against the surrounding wall surface so as to slide, an ink adhered or attached on the wall surface can be scraped off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, a printer,
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording apparatus used for an image forming apparatus used in a form such as a facsimile, and an industrial inkjet recording apparatus that performs inkjet recording on a surface of a package, a package, or a can, and particularly relates to an inkjet recording apparatus. The present invention relates to an ink jet recording apparatus characterized by an ink supply unit.

[0002]

2. Description of the Related Art An ink jet recording apparatus forms a set of dots by causing a small amount of ink droplets to fly from a minute discharge portion at the tip of a head and depositing the ink droplets on a recording medium.
An image is printed by the aggregate. In such an ink jet recording apparatus, ink is guided from an ink tank to each discharge section, and kinetic energy is applied to the ink to discharge ink droplets from the discharge section and adhere to a recording medium to form dots. . As one of the driving methods for giving kinetic energy to ink,
There is a method (electrostatic suction method) in which a voltage is applied between an ejection electrode provided near an opening and a common ejection electrode with which a recording medium is in contact, and ink is ejected by electrostatic force. This method has been attracting attention as a method for realizing a high-definition ink-jet printer since the dot diameter of ink ejected on a recording medium can be controlled by pulse width modulation of a voltage applied to a nozzle-shaped ejection electrode. .

When a printhead is manufactured by such a method, a printhead is mounted on a carriage and printing is performed while moving the printhead in a direction perpendicular to the transport direction of a print medium (scanning head). There is a method in which ink is ejected from a head having the same width as the recording medium while the head is fixed (line type head). Inexpensive inkjet recording devices required for home use, etc., often employ a scanning head type inkjet recording device, while industrial label printing requires high speed printing.
A line-type recording head is suitable and is often used.

[0004] In any type of head, when an ink jet recording apparatus is realized, an ink supply system becomes a problem because the ink is liquid. That is,
The ink jet recording apparatus requires an ink circulation system, and a pump is indispensable for this ink circulation system, so that it must be expensive. Further, depending on the complexity of the ink path and the ink supply mechanism, and the shape and form of the opening (exposed portion), clogging and sticking of the ink due to evaporation of the solvent of the ink poses a problem. Furthermore, a change in the meniscus form formed on the discharge electrode due to the fluctuation of the flow rate and the flow velocity of the ink,
The effect of variations in flying voltage on the printing stability also poses a problem.

[0005] As a printing method of the ink jet recording apparatus, for example, there is a bubble jet method or a method using a piezoelectric element or an electrostrictive element. In the ink jet system, a bubble is instantaneously generated by the heating resistor element, and the ink is caused to fly by the pressure of the bubble.In the system using the piezoelectric element or the electrostrictive element, the piezoelectric element or the electrostrictive element is used. The vibration is generated mechanically, and the ink is ejected by the pressure generated by the vibration. In these systems, both have an ink tank and supply the ink consumed in printing, and the above-described ink circulation system is unnecessary.For example, if the number of ink nozzles is increased in order to increase the resolution, The size of the head and the ink droplets is reduced, and clogging and sticking of the ink nozzle due to evaporation of the solvent are likely to occur.

For example, in the bubble jet method, steam generated at a high temperature is used as a bubble generation source. However, at a high temperature, the pigment of the ink often adheres to the wall surface of the nozzle as a fixed substance, and stable ink ejection can be performed. Disappears. Further, in the method using the piezoelectric element or the electrostrictive element, the ink supply path is more complicated than in the bubble jet method or the like, and the ink is easily clogged.

[0007] Recently, there has been an increasing demand for high-resolution printers. To cope with this, it is necessary to form ink droplets having a diameter of 20 μm or less, which are difficult to form even with the conventional ink jet recording method. However, even if the diameter can be reduced to 20 μm or less, the diameter of the ink supply system also decreases due to the decrease in diameter, and the problem of ink clogging becomes an even greater problem.

Therefore, as a method for preventing clogging and sticking of ink, an ink jet is used in which an ink chamber is shared with an adjacent discharge portion without providing a nozzle-like discharge electrode and discharge electrodes are arranged in series or in parallel. Recording methods are also known.

[0009]

However, in the ink jet recording method in which the ink chamber is shared with the adjacent discharge portion without providing the nozzle-shaped discharge electrodes individually and the discharge electrodes are arranged in series or in parallel, the nozzles are not provided. Since it is not used, the meniscus of the ink around the ejection electrode of the head must be formed stably. However, in the scanning type head in which the head moves as described above, since the head moves in the main scanning direction, the form of the ink meniscus changes and it is difficult to form a particularly stable ink meniscus. In this case, non-uniformity of the solvent and the pigment of the ink, instability of the ink supply, clogging due to evaporation of the solvent due to the provision of the opening, and sticking of the ink are particularly problematic.

The present invention has been made in view of the actual situation of such an ink jet recording apparatus, and it is an ink jet recording apparatus capable of preventing clogging and sticking of ink, and capable of stably supplying ink of a uniform concentration to a head. Is to provide.

[0011]

In order to achieve the above object, a first means is an ink jet recording apparatus for recording an image by discharging a liquid ink from a head end.
An ink case that is provided behind the tip of the head and stores ink for supplying ink to the head,
A belt-like member disposed in the ink case and a belt driving unit that drives the belt-like member and agitates the ink in the ink case are provided.

With this configuration, it is possible to supply ink from behind the head, form an ink droplet at the tip of the head, and fly the ink from the tip of the head. At that time, the ink drop can be made to fly in a free state without any obstacles on the tip end side of the head, in other words, corresponding to the physical state formed at the tip of the head. Further, the ink in the ink case for supplying the ink to the head is agitated by the belt-shaped member, so that coagulation and fixation of the ink are prevented even on the release surface of the ink to the head, and the ink having a stable and uniform concentration is obtained. Can be supplied to the head. As a result, high quality printing becomes possible.

A second means is the first means, wherein the plurality of heads are arranged so that the tip ends thereof are linear, and the belt-shaped member is arranged along the direction in which the heads are arranged. It is characterized by having. With this configuration, it is possible to easily and reliably stir the ink with a minimum number of belt members for a plurality of linearly arranged heads. In addition, a sufficient stirring action can be obtained using the belt regardless of the size of the head (the number of heads).

A third means is the ink jet recording apparatus according to the first or second means, wherein the ink tank stores the ink with the upper surface open, and ink grooves through which ink flows are provided on both sides of the head of the ink tank. The belt-shaped member is provided so as to move in the ink groove. With this configuration, when the belt is moved on both sides of the head, the ink flows in the movement direction of the belt with the movement of the belt, the ink does not stay, and the flow of the ink is promoted. In an ink jet recording apparatus using an open-top type ink case in which the solvent easily evaporates, sticking and adhesion of ink can be prevented.

A fourth means is the first or second means, wherein the ink tank stores the ink with the upper surface open, and an ink groove through which the ink flows is provided on one side of the head of the ink tank. The head is formed along one inner wall surface of the ink case, and the belt-shaped member is provided so as to move in the ink groove. With this configuration, in an ink jet recording apparatus in which the upper surface of the ink tank is open, even if the head is provided only on one inner wall surface side of the ink tank, it is possible to surely promote the flow of ink. This can prevent the ink from sticking or sticking.

According to a fifth aspect, in the third or fourth aspect, the belt-shaped member is disposed so as to be able to slide on the inner surface of the ink groove. By sliding the belt-shaped member in contact with the inner surface (or at least one inner surface) in the ink groove in this manner, a state in which the ink adhered to the inner surface is scraped off or an attempt is made to adhere to the inner surface is prevented by friction. Adhesion of ink to the inner surface can be minimized.

According to a sixth aspect, in the third or fourth aspect, the ink groove is formed in the ink case by a head support member. As described above, since the member supporting the head also serves as the member forming the ink groove, the ink jet recording apparatus can be configured with a minimum number of components.

According to a seventh aspect, in the first to fifth aspects, a surface of the belt-shaped member is provided with an uneven portion for conveying ink. The ink follows the movement of the belt member due to the viscosity of the ink itself. However, if the surface of the belt is smooth, the resistance is small and the ink layer that follows the movement of the belt is thin, and the ink amount is small. Therefore, unevenness is provided on the belt surface to increase resistance, or a so-called pocket portion for transporting ink is formed by the unevenness, thereby improving the ink followability. As a result, it is possible to improve the ink transportability and the stirring performance.

Eighth means includes first to fifth and seventh means.
In the above means, the belt-like member moves in upper and lower grooves separated by the support member. As described above, the belt member moves not only on the head side of the ink tank (upper side of the support member) but also on the bottom side (lower side of the support member) of the ink tank where pigments and the like are easily deposited. In this way, the concentration can be made uniform, and the fixation and solidification of the ink can be prevented.

The ninth means is the first to the eighth means, wherein the head, the ink tank and the belt-shaped member are arranged in one.
The arrangement direction of the heads of the unit as one unit is arranged parallel to the moving direction of the sheet, and the unit is installed so as to be movable in the sub-scanning direction.
With this configuration, it is possible to support a so-called serial printer.

According to a tenth aspect, in the first to eighth aspects, the arrangement direction of the heads of the unit having the head, the ink tank and the belt-like member as one unit is set in parallel with the main scanning direction of the paper. It is characterized by the following. With this configuration, it is possible to support a so-called line printer.

According to an eleventh aspect, in the ninth or tenth aspect, a plurality of units each including the head, the ink tank, and the belt-shaped member as one unit are arranged in parallel. With this configuration, it is possible to increase the printing density and the printing speed in a serial printer or a line printer.

In a twelfth aspect, in the first aspect, the ink case stores the ink in an open state, supplies ink from an upper end on one end of the ink case, and supplies ink from a lower end on the other end. Ink supply / discharge path for discharging ink, an ink tank connected to the ink supply / discharge path, storing ink to be supplied, and an ink pump circulating the ink stored in the ink tank through the ink path. It is characterized by having a supply means. With this configuration, the ink can be stably supplied to the ink tank by the ink supply unit. In addition, by supplying the ink from the upper end on one end side of the ink case, the ink can be supplied near the head. Can be supplied while flowing the ink, so that the ink can be stably supplied to the head, and the print quality can be improved.

The thirteenth means is the twelfth means,
When the ink is ejected from the head, the belt driving means moves the belt near the head in the same direction as the ink supply direction from the upper end by the ink supply means. With this configuration, the flow of ink near the head can be stabilized. When the ink does not fly, for example, the belt member may be reversely rotated to promote the stirring of the ink, or the fixed ink may be scraped from the opposite direction. May be performed intermittently.

The fourteenth means includes the first, second, third, fourth, ninth,
In the means of 10 and 11, the head is provided substantially perpendicular to the counter electrode, an electric field is generated by applying a voltage, and charge pigment particles made of ink are collected at the tip of the head. And a discharge electrode of an electrostatic attraction type (electric field repulsion type) for causing the air to fly. In an electrostatic suction type ink jet recording device in which the ink surface is open to the air in the ink tank, the ink is stably supplied to the head without causing fixation, coagulation, or uneven density of the ink. can do.

According to a fifteenth means, in the fourteenth means,
The discharge electrode protrudes by a predetermined amount from the ink level of the ink tank. With this configuration, the pigment particles in the ink are guided from the back side of the head to the tip of the head that protrudes from the ink liquid surface, so that an ink droplet having a stable droplet diameter can be formed.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an ink jet recording apparatus according to the present invention will be described with reference to the drawings.

<First Embodiment> FIG. 1 is a schematic structural view showing a first embodiment of the ink jet recording apparatus of the present invention.

In FIG. 1, the ink jet recording apparatus basically includes a recording system R, an ink supply system S, and a print control system C. The recording system R includes a recording head 1. The recording head 1 includes a plurality of ejection electrodes (heads) 2, an ink case 3 for storing ink 5, a belt 4, a drive motor 6, a pulley 7, a support member 9, and a motor control unit. Consists of eleven. The ink supply system includes an ink tank 8, an ink bypass 10 (10a, 10b), a circulation pump 17, and a pump control unit 18. The control system C includes an applied power supply 12 including a pulse power supply 15 and a bias power supply 16. Further, a counter electrode 13 is disposed at a position facing the ejection electrode 2 at a predetermined interval. It is placed in close contact with the surface of the counter electrode 13 facing the discharge electrode 2.

The ink tank 8 stores the ink 5 in an open state, and is connected to an ink bypass 10 connected to the ink case 3. Supply-side ink bypass 10
a is an upper end side of the ink case 3 and is opened upstream of the ejection electrode 2 in the belt movement direction, and an ink bypass 10b on the discharge side is a lower end side of the ink case 3 and downstream of the ejection electrode in the belt movement direction. It is open to. The discharge-side ink bypass 10b is connected to an upper portion of the ink tank 8, and the supply-side ink bypass 10a is connected to a lower portion of the ink tank 8. Thus, ink is supplied from the ink tank 8 to the upper layer area of the ink case 3 by the circulation pump 17 provided in the ink bypass 10a on the supply side, and the ink tank 8 is supplied from the lower layer area of the ink case 3
The ink circulation system that returns the ink to the ink case 3 enables stable supply of ink to the ink case 3.

The ink 5 is a mixed ink composed of a solvent and charged pigment particles, and has a concentration of 0.1% to 10% (charge pigment particles / solvent). The ink concentration is preferably a dilution concentration of 0.5% to 7%. In addition, magenta, cyan, yellow, and black are used as pigment coloring agents.

As shown in FIG. 2, the ink case 3 has two inner wall surfaces 31a, 31a and 32, which form the ink case 3.
The groove formed by the upper and lower ink case portions formed by the support member 9 and sandwiched by the support member 9 in FIG. 2 becomes the ink grooves (flow paths) 33 and 34. The ejection electrodes 2 are arranged in series at the center of the support member 9 and are supported by the support member 9. An applied power supply 12 composed of a pulse power supply 15 and a bias power supply 16 is connected to the ejection electrode 2. Further, as can be seen from FIG. 2, the belts 4 are arranged in two rows with the ejection electrodes 2 interposed in the ink grooves 33 and 34 in the ink case 3. The belt 4 is stretched between a pair of pulleys 7, and one of the pulleys 7 has a driving motor 6
The drive motor 5 is connected to a motor controller 11 for controlling the feed speed.

The material of the ink case 3 and the support member 9 is an insulating material (resin, ceramic, glass, or the like).
Is desirable. As described above, a plurality of ejection electrodes 2 are arranged in series (line head type) in the same shape at a predetermined interval at the center of the support member 9 and fixed in a stable state. In order to obtain good printing accuracy, it is necessary to precisely define the pitch between ejection electrodes and the amount of protrusion.
Further, the positional relationship of the ejection electrode 2 with respect to the upper surface end 23 of the ink case 3 may be either a protruding state or a retracted state. In the present embodiment, the ejection electrode 2 is in a protruding state.

The upper end 23 of the ink case 3 of the ink case 3
The purpose of making the leading end of the ejection electrode 2 protrude is to increase the depth dimension of the grooves 33 and 34 serving as ink flow paths, to facilitate the arrangement of a belt between the ejection electrodes 2, and to secure the ink flow path. That's why. Further, by separating the tip of the discharge electrode 2 from the meniscus position composed of ink, the electric field can be concentrated and the flying applied voltage can be suppressed low. This is because exposure of the tip of the discharge electrode 2 to air is superior to concentration of an electric field even from the viewpoint of the dielectric constant.

Two belts 4 are arranged in the ink grooves 33 and 34 in the ink case 3 (both sides with respect to the ejection electrode 2). The number of the belts 4 is arbitrarily set as appropriate according to the mode of the recording head 1. The belt 4 is endless, is appropriately tensioned so as not to slip by pulleys 7 at both ends, and is driven to rotate in the longitudinal direction by a drive motor 6. The belt 4 is connected to the motor controller 11
Controls the rotation speed of the drive motor and the belt feed speed.

The belt 4 moves the ink 5 along the ink groove 33.
(The flow direction of the ink 5 and the sliding direction of the belt 4 are the same direction), and the ink case 3 is moved intermittently (including intermittently) or continuously while rubbing the inner wall of the ink case 3 and the side surface of the discharge electrode 2. . As a result, the ink pigment does not adhere to the inside of the ink groove 33 and the ejection electrode 2, and even if it adheres, the adhered substance is scraped off, and the ink adheres to the belt sliding surface of the ink groove 33 and the ejection electrode 2. Will not be done. Further, since the ink 5 follows the movement of the belt 4, the ink is agitated when the belt 4 moves. Due to this stirring action, fluctuations in the ink flow rate and the flow velocity can be suppressed, and a stable meniscus form is formed on the ejection electrode. As a result, it is possible to suppress the printing state from becoming unstable due to the variation of the flying voltage and the ink droplet 22. Further, since the ink flows stably, even if the ink flow path is a narrow groove, the ink can flow stably without overflowing.

Further, a return belt is disposed in the ink groove 34 on the bottom side of the ink case 3. With such a configuration, the ink 5 in the ink case 3 is agitated by sliding and moving, and particularly, sedimentation, non-uniformity and concentration of the ink in the bottom layer, fixation, aggregation, and the like are reduced. In this embodiment, the belt 4 is slidably moved on the inner wall surface of the ink case 3 or the side surface of the discharge electrode 2, but is moved.
If the pigment is difficult to adhere or adhere, it is not necessary to slide the inner wall surfaces 31a, 32a and the side surfaces to scrape off the adhered matter.
It is also possible to adopt a configuration in which the ink jet head is moved while being separated from the side surface a or the side surface and has only the ink stirring function. Further, depending on the groove shape and the depth of the groove, it is also possible to make a configuration such that only the bottom surface is in sliding contact with the ink groove 33, 34.
It may be appropriately designed in an optimal state according to the shape and depth of the belt 4, the size of the belt 4 and the properties of the pigment.

The belt 4 is formed endlessly (endless) with resin, inorganic material (such as ceramic) or other insulating material. As an embodiment, a single line or a plurality of lines may be used. In the case of a plurality of lines, a stranded line, a braided line, a chain line, or the like may be used. Further, the cross-sectional shape of the belt 4 can be various shapes such as a circle, an ellipse, a square, a trapezoid, a star, a saw blade, a waveform, and a brush flocking. Functionally, it is preferable that the ink 5 has a large transporting function and a stirring function. Therefore, it is more preferable that the surface of the belt 4 is formed with irregularities such that the ink is easily attached and moves.

FIG. 3 is a sectional view taken along line AA of FIG. 1. This example shows an example using a belt 4a having a different sectional shape from the belt in FIG. When the belt 4a is a single line and has a star-shaped outer periphery (including a radial brush), the inner surfaces 31a, 32 of the walls 31, 32 forming the grooves 33, 34 are formed.
a, the upper surface of the support member 9, or the bottom surface of the ink tank 3, or even the ink immersion portion of the discharge electrode 2, when the ink 5 adheres to the sliding contact surface is scraped to prevent the ink 5 from adhering or sticking. Function can be exhibited more effectively.

FIG. 4 is a schematic view showing a part of the ink case 3 in detail from the upper surface direction (the side facing the recording medium). In this example, the belt 4b is formed by a single line, and one side thereof (the side facing the ejection electrode 2) is saw-toothed so that the scraping of the ink 5 fixed at the ink immersion portion of the ejection electrode 2 is considered. It is. In addition, since a transport pocket for holding the ink 5 is formed in a concave portion generated by the irregularities of the saw blade,
The ability to transport ink 5 is also high, and a stable ink transport function can be exhibited.

FIG. 5 is a schematic view showing a part of the ink case 3 in detail from the upper surface direction (the side facing the recording medium). In this example, the belt 4c is an endless belt formed by connecting spherical beads in a chain. By adopting such a shape, the belt 4c is brought into sliding contact with the inner surfaces 31a and 32a of the walls 31 and 32, and excessively. Since it is easy to deform when a strong force is applied, it has high abrasion resistance and is effective in extending the life. Further, as described above, since there are many irregularities, there is an advantage that the ability to transport the ink 5 is large.

The relationship between the belt 4 (4a, 4b, 4c) and the ink 5 is such that the belt is in contact with the ink grooves 33, 34 at the bottom when the intention is to scrape off the fixed ink 5. And the ink wraps around it,
It is also important that there be an appropriate amount of ink layer on top of the belt. However, since the ink 5 is hard to be fixed due to the relationship between the solvent and the pigment, if there is no need to consider the fixation, the ink 5 is simply moved in the ink grooves 33 and 34 to ensure the ink transportability and the stirring performance. It may just be. In this case, since the belt 4 does not actively contact the inner surfaces of the ink grooves 33 and 34, the life of the belt 4 can be further extended.

Also, depending on the flight conditions of the ink droplets, the belt 4
Feed speed, ink amount (amount per volume in groove 33),
And a relationship between the ink density and the ink density. In addition to the above-described conditions, the relationship between the amounts of ink in the ink case 3 is set at a position where the ink liquid level is kept low relative to the upper surface 23 of the ink case 3. To create that state, the circulation pump 17
Since the control of the discharge amount and the control of the feed amount of the belt 4 are greatly related to the capacity of the ink groove 33, the control is performed in accordance with the optimum value according to the flight condition. These optimum values are experimentally determined according to the component composition of the ink 5 and each of the above-described elements. These are combined to supply the ink to the narrow ink groove 33,
It is possible to effectively obtain actions such as prevention of ink sticking and cleaning, thereby stabilizing the flight of ink droplets and obtaining a desired dot diameter, and as a result, obtaining a high quality image. .

The opposing electrode 13 is disposed opposite to the discharge electrode 2 at a predetermined interval, and is disposed in a state of facing the discharge electrode 2. The opposing electrode 13 may be a flat plate or a cylindrical drum. Side), the recording medium 14 is placed in close contact with the recording medium 14. At this time, the opposing electrode 13 (including the recording medium 14) faces the ejection electrode 2 so as to be vertical, and the opposing gap (the tip of the ejection electrode 2 and the opposing electrode 13
It is important to set the surface or outer peripheral edge) with high accuracy. The allowable range of the gap is desirably about 0.1 mm at the maximum. The permissible range of the arrangement and the gap is such that the variation in the opposing gap and the variation in the deflection angle of the discharge electrode 2 with respect to the counter electrode 13 (the attitude of the discharge electrode 2 with respect to the counter electrode 13) are related to the change in the flight direction. The variation relates to a change in the flying applied voltage. The relationship between the gap amount and the flying voltage is
The larger the gap, the higher the applied voltage. Further, if the gap amount exceeds a certain amount, the form of the ink droplet and the flying position will vary, so that a desired dot diameter cannot be obtained and a high-quality image cannot be obtained. Therefore, the gap amount needs to be strictly controlled.

In order for the ink droplet 22 to fly from the ejection electrode 2 to the recording medium 14 on the counter electrode 13, the ejection electrode 2
Need to apply voltage. The application power supply 12 includes a pulse power supply 15 and a bias power supply 16. When a predetermined voltage is applied to the discharge electrode 2 at a predetermined timing by the bias power supply 16 and the pulse power supply 15, a pigment is applied to the tip of the discharge electrode 2 by the action of the electric field. The particles concentrate and form aggregates,
The agglomerates fly as ink droplets by breaking the solvent surface due to electrostatic repulsion. Then, the ink droplets 22 flying from the ejection electrodes 2 adhere to the recording medium 14 to enable printing and application. The principle and operation of the ink jet recording system utilizing the action of the electric field are well-known technologies, and thus description thereof will be omitted.

The material of the counter electrode 13 is a conductive metal, for example, AI, Cu, SUS or the like. The surface may be subjected to a plating treatment, but in that case, the plating layer needs to be a conductive material.

In the present embodiment, the shape of the discharge electrode 2 is a triangular plate, and the discharge tip 2a is conical and acute. As a result, the electric field is easily concentrated, and the applied voltage can be kept low. The material of the ejection electrode 2 is preferably a conductive material. In the present embodiment, a conductive metal material having good workability (either magnetic or non-magnetic) is used. However, a non-conductive material may be used. It is not something to be done.

With such a configuration, it is possible to cope with diversification of the ink jet recording head with a simple configuration.

<Second Embodiment> FIG. 6 is a sectional view showing a recording head 1 of an ink jet recording apparatus according to a second embodiment, in which a plurality of discharge electrodes 2 shown in FIGS. 1 and 2 are arranged in parallel. And laminated. This recording head can be applied to both a serial printer and a line printer.

The individual ejection electrodes 2 are located at the center, and ink grooves 33 and 34 formed of the ink case 3 and the support member 9, and the belts 4 are arranged on both sides of the ink grooves 33 and 34 in the same arrangement as in FIG. Be composed. A driving motor 6 for applying a driving force to the belt 4 is provided with a pulley 7 on the driving side in the same manner as in the first embodiment.
Built-in, in this case, six belts 4 with one motor
Drive. For this reason, the pulley 7 has a plurality of grooves cut integrally, and the belt 4 is multiplied (six) to simultaneously rotate. With this configuration, cost reduction and control simplification can be achieved. Incidentally, when the recording heads 1 are stacked in three layers and the three members are arranged in a staggered manner, the recording density can be tripled as compared with the one having one layer as shown in FIG. If three dots are printed simultaneously in the same phase, the printing speed can be tripled.

The other components other than the recording head are configured in the same manner as in the first embodiment, and a description thereof will be omitted.

<Third Embodiment> FIG. 7 is a sectional view showing a recording head of an ink jet recording apparatus according to a third embodiment. In this embodiment, the ejection electrode 2 of the ink jet recording apparatus shown in FIG.
It is characterized in that it is arranged close to the inner wall surface 31a of the first.
That is, the inner surface 31 of the wall surface 31 on one side of the ink case 3
a, and the ink grooves 33, 34 are formed via the support member 9, and the ink grooves 33, 3 are formed.
4, one belt 4 similar to that of the first embodiment is arranged.

By arranging the discharge electrode end 2 at the end face of the ink case 3 in this manner, fine processing and high-quality head manufacture can be performed by etching, which is a thin film process used in liquid crystal technology. Moreover, since it is not necessary to provide the ink grooves 33 and 34 on both sides of the discharge electrode 2 in the horizontal direction, the recording head can be made compact by the width of one of the ink grooves.

The other components other than the recording head are configured in the same manner as in the first embodiment, and thus description thereof is omitted.

[0055]

As is apparent from the above description, according to the present invention, there is provided an ink case provided behind the tip of the head for storing ink for supplying ink to the head, and the ink case. A belt-shaped member disposed in the inside, and a belt driving unit that drives the belt-shaped member and stirs the ink in the ink case.
The stirring of the ink is reliably performed by the belt, and the fixation, coagulation, and density unevenness of the ink can be suppressed, and the ink can be stably supplied to the head.

Further, according to the present invention, since the belt member moves in the narrow ink groove, the ink can be reliably stirred and transported.

Further, according to the present invention, since the belt-shaped member is disposed so as to be able to slide on the inner surface of the ink groove, it is possible to scrape the ink fixed on the inner surface of the ink groove, and to form the ink fixing layer. Growth can be prevented. As a result, an ink flow path can be secured, and stable ink supply can be achieved.

An ink supply / discharge path for supplying ink from an upper end on one end of the ink case and discharging ink from a lower end on the other end is connected to the ink supply / discharge path to store the ink to be supplied. Ink supply means including an ink tank to be circulated and an ink pump for circulating the ink stored in the ink tank through the ink path. The belt member disposed in the ink tank is moved to protrude from the ink release surface. Since the ink is supplied to the completed head, a complicated and fine ink supply path is not required, and the ink can be stably supplied at low cost.

Further, according to the present invention, the agitation of the ink and the fixation and aggregation of the ink are prevented by moving the belt member in a state where the belt member is immersed in the ink in the ink tank. It is possible to This type of ink supply apparatus is particularly suitable for an ink jet recording apparatus using an open type ink tank in which the volatilization of ink is intense.

Further, according to the present invention, stable ink supply to the head is possible, so that the diameters of the ink droplets flying from the head end are uniform, thereby improving the printing quality.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic configuration of an ink jet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a recording head portion and a counter electrode of the inkjet device shown in FIG.

FIG. 3 is a cross-sectional view of a recording head using a belt of another shape.

FIG. 4 is a plan view showing a part of a recording head using a belt of another shape.

FIG. 5 is a plan view showing a part of a recording head using a belt of another shape.

FIG. 6 shows a second arrangement in which discharge electrodes are arranged in parallel (laminated type).
FIG. 3 is a cross-sectional view of the recording head according to the embodiment.

FIG. 7 is a cross-sectional view of a recording head according to a third embodiment in which ejection electrodes are arranged on one wall surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Discharge electrode 3 Ink case 4 Belt 5 Ink 6 Drive motor 7 Pulley 8 Ink tank 9 Support member 10 Ink bypass 11 Motor control unit 12 Applied voltage 13 Counter electrode 14 Recording medium 15 Pulse power supply 16 Bias power supply 17 Circulation pump 18 Pump control unit 22 Ink droplet 23 Ink case upper surface end 31, 32 Ink case wall 31a, 32a Inner wall surface of ink case 33, 34 Ink groove

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mamoru Okano 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Yoshinobu Fukano 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture No. 1 Hitachi, Ltd. Hitachi Research Laboratory (72) Inventor Toru Miyasaka 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture F-term in Hitachi Research Laboratory, Hitachi Ltd. F term (reference) 2C056 EA26 EC07 EC20 EC46 FA07 HA05 KB16

Claims (15)

[Claims] 1. An ink jet recording apparatus for recording an image by ejecting liquid ink from a head end, comprising: an ink case provided behind the head end to store ink for supplying ink to the head; An ink jet recording apparatus comprising: a belt-shaped member disposed in the ink case; and a belt driving unit that drives the belt-shaped member and stirs the ink in the ink case. 2. The head according to claim 1, wherein the plurality of heads are arranged so that the tip ends thereof are linear, and the belt-shaped member is arranged along the direction in which the heads are arranged. The inkjet recording apparatus according to any one of the preceding claims. 3. The ink case stores ink with an upper surface open, and ink grooves are provided on both sides of the head of the ink case, and the belt-like member is stretched so as to move in the ink grooves. The ink jet recording apparatus according to claim 1, wherein the recording is performed. 4. The ink case stores ink with the top surface open, and an ink groove is provided on one side of the head of the ink case, and the head is formed along one inner wall surface of the ink case. The ink jet recording apparatus according to claim 1, wherein the belt-shaped member is stretched so as to move in the ink groove. 5. The ink jet recording apparatus according to claim 3, wherein the belt-shaped member is disposed so as to be able to slide on an inner surface of the ink groove. 6. The ink jet recording apparatus according to claim 3, wherein the ink groove is formed in the ink case by a head support member. 7. The method according to claim 1, wherein the surface of the belt-shaped member has an uneven portion for conveying ink.
6. The ink jet recording apparatus according to any one of claims 1 to 5. 8. The ink jet recording apparatus according to claim 1, wherein the belt-like member moves in upper and lower grooves separated by the support member. 9. A unit in which the head, the ink tank, and the belt-like member are arranged as one unit, and a head arrangement direction is arranged in parallel with a sheet moving direction, and the unit is installed so as to be movable in a sub-scanning direction. The ink jet recording apparatus according to any one of claims 1 to 8, wherein: 10. The apparatus according to claim 1, wherein the direction in which the heads, the ink tank, and the belt-shaped member are arranged as one unit is arranged in parallel with the main scanning direction of the sheet. Item 2. An ink jet recording apparatus according to item 1. 11. The ink jet recording apparatus according to claim 9, wherein a plurality of units each including the head, the ink tank, and the belt-shaped member as one unit are arranged in parallel. 12. An ink supply / discharge path for storing ink in an open state, supplying ink from an upper end at one end of the ink case, and discharging ink from a lower end at the other end of the ink case. An ink supply means connected to an ink supply / discharge path and including an ink tank for storing ink to be supplied, and an ink pump for circulating the ink stored in the ink tank via the ink path; The ink jet recording apparatus according to claim 1, wherein 13. The method according to claim 13, wherein the belt driving means moves the belt near the head in the same direction as the ink supply direction from the upper end by the ink supply means when flying the ink from the head. The ink jet recording apparatus according to claim 12, wherein 14. The head is provided substantially perpendicular to a counter electrode, generates an electric field by applying a voltage, collects charge pigment particles made of ink at the tip of the head, and flies the ink toward the counter electrode. 4. The method according to claim 1, further comprising an electrostatic suction type discharge electrode.
12. The inkjet recording apparatus according to any one of 9, 10, and 11. 15. The ink jet printer according to claim 1, wherein the discharge electrode protrudes by a predetermined amount from an ink level of the ink tank.
5. The ink jet recording apparatus according to 4.