JPH091824A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE: To provide an ink jet recording apparatus capable of preventing the adhesion of toner particles to the leading end parts of recording electrodes caused by the sedimentation of toner particles in ink. CONSTITUTION: A cavity 4 housing ink has an aperture part 2 for flying ink to the outside longitudinally provided to the front thereof and a plurality of recording electrodes 3 are provided in the aperture part 2 so as to be arranged at an almost equal interval. An ink supply hole H1 is provided to the upper surface of the cavity 4 and an ink recovery hole H2 is provided to the rear surface thereof. Ink flows in the cavity 14 from a supply pipe 5 through the ink supply hole H1 to be guided by the prescribing member 8 and inclined surface 4a in the cavity 14 to flow toward the leading end parts of the recording electrodes 3. The excessive ink not flown from the recording electrodes 3 is guided by the prescribing member 8 and inclined surface 4b in the cavity 4 to flow and recovered through the ink recovery hole H2 provided to the bottom part of the cavity 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention uses an ink in which charged colorant particles (toner particles) are dispersed in an insulating liquid (liquid carrier) to generate ink droplets by applying electrostatic force. The present invention relates to an inkjet recording apparatus that records an image by flying the generated ink droplets on a recording medium by electrostatic force.

[0002]

2. Description of the Related Art Recently, in the field of personal printers,
2. Description of the Related Art Printers called inkjet recording apparatuses, which form a desired image on a recording medium by ejecting ink droplets onto the recording medium, are widely used.

In such an ink jet recording apparatus,
A piezoelectric element, a heating element, or the like is used as a drive source for generating ink droplets. However, in these ink jet recording apparatuses, since a dye is used as a colorant, there is a problem that image storability is not sufficient, such as poor light resistance of recorded images and poor water resistance of recorded images.

Further, it is difficult to widely change the size of the generated ink droplets according to the recording signal. Therefore, the gradation method for changing the density in units of image points cannot be adopted, and the dither method using the binary recording image points, etc. The gradation image recording is performed by the gradation method. For this reason, it is difficult to obtain a recorded image with high definition and smooth gradation characteristics.

Further, the ink jet recording apparatus which is popular nowadays is a serial printer, which outputs one recording medium as compared with a laser printer adopting an electrophotographic system or a thermal transfer printer having a line thermal head. There is a problem that the time is long and high-speed output is difficult.

In the ink jet recording head currently in practical use, ink droplets are formed from the orifice.
Inkjet recording heads for full-size line printers are under development.
Thousands of orifices are required for size, and all of these orifices are not highly reliable without causing clogging.

In order to deal with this problem, an oil-based ink is supplied to a slit formed by an electrode array plate and a flat plate without providing an orifice, and an ink drop is ejected from the slit by an electrostatic force generated by supplying power to a recording electrode. A so-called slit jet method of flying is being studied.

In this slit jet system, since there is no use of an orifice which is a minute opening, there is no fear of ink clogging. However, the solubility of oil-soluble dyes in organic solvents is low, it is difficult to obtain high image density, or there is no yellow, magenta, or cyan dye with good balance of each color suitable for full-color recording. There is a problem that it has not been obtained.

Therefore, in order to solve these problems, a slit jet type recording apparatus using an ink in which charged colorant particles are dispersed in an insulating liquid has recently been developed.

Here, the ink jet recording apparatus will be briefly described. This inkjet recording device
The conductive ink supply tube is inside the conductive base, and the ink in which the charged colorant particles are dispersed in the insulating liquid is supplied into the ink supply tube. The tip of the ink supply tube is about 30 in the direction of ink flow.
The discharge position at the tip of the ink supply tube has a small radius of curvature. A predetermined recording voltage is applied to the ink supply tube.

Further, facing the ink supply tube,
There is a counter electrode held at ground potential. In addition, the excess ink that was supplied to the ink supply tube and did not fly,
It is guided to the surplus ink recovery path by the ink flow guide material. The ink in the surplus ink collection path is collected in the ink tank by a pump or the like.

When ink containing colorant particles charged to the same polarity as the recording voltage applied to the ink supply tube is supplied into the ink supply tube by the ink supply device,
The ink moves toward the ejection position, which is the flying point, at the tip of the ink supply tube.

When a recording voltage is applied to the ink supply tube, strong electric field concentration occurs at the ejection position at the tip of the ink supply tube. The colorant particles in the ink near the ejection position move to the ejection position by the action of strong electric field concentration, and the concentration of the colorant particles in the ink near the ejection position increases. Ink containing color material particles with a higher concentration than the bulk ink is drawn out in a filament form from the ejection position. Since the drawn-out ink filament contains high-concentration particles of the same polarity, it splits due to the electrostatic repulsive force between the particles to form fine ink droplets, which fly toward the counter electrode.

This ink jet recording apparatus is characterized in that the coloring material particles in the ink are made to fly at a higher density than the original ink, and by utilizing the density of the coloring material particles, it is possible to use the slits more than before. It improves the selectivity of ink droplet generation. Further, conventionally, since a nozzle corresponding to a flying droplet size such as ink jet recording is not used, there is no fear of nozzle clogging, and pigment particles can be used. Therefore, problems such as image storability and light resistance, which are problems of the conventional inkjet recording, are solved.

[0015]

However, the above-mentioned ink jet recording apparatus has the following problems. That is, the surplus ink that has not flown is guided to the surplus ink recovery path by the ink flow guide material and is recovered in the ink tank. However, it is difficult to suck the ink that has flowed out of the ink supply tube into the fine ink recovery path once, and the ink may adhere to the conductive base or spill into the device.

Further, the ink always flows from the ink supply tube through the ink flow guide material and flows into the recovery passage.
Since this flow is such that it flows back at the tip of the ink supply tube, the flow easily vibrates and the ink position at the tip of the ink supply tube also moves. in this case,
For example, at the position where the ink is retracted at the tip of the ink supply tube, there is no ink at the tip, and the flight becomes unstable. When the ink reaches the tip of the ink supply tube, the tip of the ink has exceeded the tip of the ink supply tube, so the electric field is weak and the flight becomes unstable.

Therefore, the present invention provides an ink jet recording apparatus which can prevent the colorant particles from adhering to the tip of the recording electrode due to the precipitation of the colorant particles in the ink and always obtain stable recording characteristics. With the goal.

[0018]

An ink jet recording apparatus of the present invention contains an ink in which charged colorant particles are dispersed in an insulating liquid and causes the ink to fly to a recording medium. An ink containing portion having an ejecting portion for supplying the ink to the ink containing portion, an ink supplying means for supplying the ink to the ink containing portion, and a tip portion provided in the ink containing portion and having a predetermined position. When a recording voltage is applied, the ink in the ink containing portion is ejected toward the recording medium, and the ink in the ink containing portion is recovered from the lowest point in the gravity direction of the ink containing portion. And an ink collecting unit that does.

Further, the ink jet recording apparatus of the present invention contains an ink in which charged colorant particles are dispersed in an insulating liquid, and ejects the ink to a recording medium. An ink containing portion having an ink supply means for supplying the ink to the ink containing portion, a tip portion located in the ink containing portion, and a predetermined recording voltage applied. By doing so, the recording electrode that causes the ink in the ink containing portion to fly toward the recording medium, and the excess ink that has not been jetted by the recording electrode is guided to the position that is the lowest point in the gravity direction of the ink containing portion. Ink guiding means,
An ink recovery unit for recovering the excess ink guided by the ink guide unit is provided from a position which is the lowest point in the gravity direction of the ink storage unit.

Further, the ink jet recording apparatus of the present invention stores an ink in which charged colorant particles are dispersed in an insulating liquid, and ejects the ink onto a recording medium. An ink containing portion having an ink supply means for supplying the ink to the ink containing portion, a tip portion located in the ink containing portion, and a predetermined recording voltage applied. By doing so, the recording electrode that causes the ink in the ink containing portion to fly toward the recording medium, and the excess ink that has not been jetted by the recording electrode is guided to the position that is the lowest point in the gravity direction of the ink containing portion. Ink guiding means,
An ink recovery unit that operates during non-recording and recovers excess ink guided by the ink guide unit from a position that is the lowest point in the gravity direction of the ink storage unit is provided.

Further, the ink jet recording apparatus of the present invention stores an ink in which charged colorant particles are dispersed in an insulating liquid and ejects the ink onto a recording medium. An ink containing portion having an ink supply means for supplying the ink to the ink containing portion, a tip portion located in the ink containing portion, and a predetermined recording voltage applied. By doing so, the recording electrode that causes the ink in the ink containing portion to fly toward the recording medium, and the excess ink that has not been jetted by the recording electrode is guided to the position that is the lowest point in the gravity direction of the ink containing portion. Ink guiding means,
An ink recovery unit is provided which operates when an ink recovery instruction is issued and recovers excess ink guided by the ink guide unit from a position which is the lowest point in the gravity direction of the ink storage unit.

Further, the ink jet recording apparatus of the present invention contains an ink in which charged colorant particles are dispersed in an insulating liquid, and ejects the ink to the recording medium. An ink containing portion having an ink supply means for supplying the ink to the ink containing portion, a tip portion located in the ink containing portion, and a predetermined recording voltage applied. As a result, a recording electrode that causes the ink in the ink containing portion to fly toward the recording medium and the recording electrode in the ink containing portion are installed, and the tip of the recording electrode is above the ink containing portion in the direction of gravity. From the position where the rear end of the recording electrode is inclined so as to face the direction of gravity of the ink containing portion and the lowest point of the ink containing portion in the direction of gravity. And comprising an ink recovery means for recovering the ink in the serial ink accommodating portion.

Further, the ink jet recording apparatus of the present invention contains an ink in which charged colorant particles are dispersed in an insulating liquid, and ejects the ink to a recording medium. An ink containing portion having an ink supply means for supplying the ink to the ink containing portion, the ink containing portion being provided in the ink containing portion, and the respective tip portions arranged linearly in the discharge portion, By selectively applying a predetermined recording voltage, a plurality of recording electrodes that cause the ink in the ink containing portion to fly toward the recording medium, and a tip portion of the ejection portion and the recording electrodes when not recording are formed. Rotating means for rotating the ink containing portion so as to face upward in the direction of gravity and to direct the ejection portion and the tip of each of the recording electrodes in a direction orthogonal to the direction of gravity during recording. And an ink recovery unit that recovers ink in the ink storage unit from a position that is the lowest point in the gravity direction of the ink storage unit when the ejection unit and the tip of each of the recording electrodes face upward in the gravity direction. It has.

Further, the ink jet recording apparatus of the present invention stores an ink in which charged colorant particles are dispersed in an insulating liquid and ejects the ink onto a recording medium. An ink containing portion having an uppermost position in the gravitational direction, an ink supply means for supplying the ink to the ink containing portion, a vertical state provided in the ink containing portion, and a tip portion for discharging the ink. Located inside the unit, and by applying a predetermined recording voltage,
The recording medium is provided with a recording electrode for ejecting the ink in the ink containing section toward the recording medium, and an ink collecting means for collecting the ink in the ink containing section from a position which is the lowest point in the gravity direction of the ink containing section. There is.

[0025]

According to the present invention, since the ink collecting means for the ink containing portion is located at the lowest point in the gravity direction of the ink containing portion, the colorant particles that settle down flow into the ink collecting means. Furthermore, since the surface forming the recording electrode is inclined such that the tip of the recording electrode faces upward in the direction of gravity, the colorant particles that settle may be deposited near the tip of the recording electrode or in the vicinity of the ejection section of the ink containing section. Does not adhere.

In addition, when the ink recovery command is executed during the non-recording operation or immediately after the recording operation is completed, the ink in the ink containing section is recovered. At this time, since the ink is collected by the ink collecting means from the lowest position in the gravity direction of the ink containing portion, all the ink in the ink containing portion flows into the ink collecting means. further,
Since the surface forming the recording electrode is inclined such that the tip of the recording electrode faces upward in the direction of gravity, the colorant particles in the ink also flow into the ink collecting means without adhering to the tip of the recording electrode. .

During the non-recording operation, the ink containing portion is rotated so that the recording electrode is substantially vertical and the tip of the recording electrode faces upward. Further, in this state, the ink collecting means is arranged so as to be below the ink containing portion, so that even if the colorant particles in the ink containing portion settle, the vicinity of the tip of the recording electrode or the ejecting portion The ink does not adhere to the ink collecting unit and is collected by the ink collecting unit from the lower side of the ink containing unit.

Further, the recording electrodes are arranged in a substantially vertical direction and the tip portions of the recording electrodes are directed upward regardless of the presence or absence of the recording operation, and the ink collecting means is located below the ink containing portion. Since the colorant particles in the ink containing portion are settled in such a manner that they do not adhere to the tip of the recording electrode or the vicinity of the ejecting portion, the ink from the lower side of the ink containing portion is attached by its own weight. It is collected by the collecting means.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment will be described. 1 and 2 show the main part of the inkjet recording apparatus according to this embodiment. That is, the inkjet recording head 1 includes the ink cavity 4 as an ink storage portion that stores the ink 7. Cavity 4
Is formed in a housing whose longitudinal side surface is polygonal and long in the main scanning direction, and serves as an ejection portion for ejecting the ink 7 to the outside in the longitudinal direction (main scanning direction) of its front surface. It has a slit-shaped opening 2. in this case,
Front surfaces 4a, 4 of the cavity 4 located above and below the opening 2
b is an inclined surface that inclines so as to approach each other in the direction of the opening 2.

Here, the ink 7 will be described. In this embodiment, the ink 7 in which the toner particles (coloring material particles) charged in advance to the positive potential are dispersed in the liquid carrier (insulating liquid) is used, and ink droplets are generated by electrostatic force. More specifically, for example, the ink 7 is a color carrier such as a carbon black in a liquid carrier (insulating liquid) such as a petroleum solvent (insulating liquid) or on the surface thereof, a dispersant, a charge control agent. A dispersion of toner particles containing an agent is used.

On the lower inclined surface 4b in the cavity 4, a plurality of recording electrodes 3 arranged at substantially equal intervals in the main scanning direction are provided, and the respective tip portions of these recording electrodes 3 are opened. Located in part 2. In this case, the tip portions of the recording electrodes 3 are arranged so as to be aligned in a line in the main scanning direction, and are slightly projected from the opening 2 to the outside.

The recording electrodes 3 are provided by the number corresponding to the recording width and the recording resolution, and are arranged in parallel on the inclined surface 4b while being electrically independent from each other. Further, a predetermined recording voltage (Vej) is selectively applied to the recording electrode 3 from a recording head drive circuit described later.

With such a configuration, the inclined surface 4b on which the recording electrodes 3 are arranged has an inclination such that the tip of the recording electrode 3 faces upward in the direction of gravity, so that the toner particles in the ink 7 are also included. The ink does not adhere to the tip of the recording electrode 3 and easily flows into an ink recovery hole H2 described later.

A plate-shaped regulating member 8 for regulating the flow of the ink 7 is provided in a substantially horizontal state at a position facing the opening 2 in the cavity 4. Further, a transport electrode 9 that transports toner particles in the ink 7 is provided at a position substantially facing the opening 2 in the cavity 4. A voltage having the same polarity as that of the toner particles is applied to the transport electrode 9 from a recording head drive circuit described later. For example, in this embodiment, since the toner particles are charged to a positive potential, the transport electrode 9 is also given a positive potential (Vep).

An ink supply hole H1 for supplying ink 7 into the cavity 4 is provided on the upper surface of the cavity 4, and an ink recovery hole H2 for recovering the ink 7 in the cavity 4 is provided on the lower surface (bottom portion) thereof. ing. The supply pipe 5 is connected to the ink supply hole H1, and the recovery pipe 6 is connected to the ink recovery hole H2.

With this structure, the ink 7 flows from the supply pipe 5 into the cavity 4 through the ink supply hole H1, and the regulating member 8 and the inclined surface 4a in the cavity 4 are accommodated.
Guided by and, it flows in the direction of the tip of the recording electrode 3 as shown by arrow A in the figure. The excess ink 7 that has not flown from the recording electrode 3 is guided by the regulating member 8 and the inclined surface 4b in the cavity 4 and further flows as shown by an arrow B in the drawing, and the bottom portion in the cavity 4 (the direction of gravity of the cavity 4). The ink is collected from a recovery pipe 6 to a recovery tank (not shown) through an ink recovery hole H2 provided at the lowest point).

A counter electrode 11 is provided in front of the recording head 1 and at a position separated from the recording head 1 by a predetermined distance so as to face the recording electrode 3 (opening 2). Is held at ground potential. The counter electrode 11 and the recording electrode 3 are in contact with the counter electrode 11.
A recording paper 12 as a recording medium is arranged between the tip of the recording paper 12 and the front end of the recording paper.

FIG. 3 is a diagram for explaining the movement of the charged toner particles 10 in the ink 7. As previously mentioned,
A counter electrode 11 is arranged so as to face the recording electrode 3, and a recording paper 12 is in contact with the counter electrode 11.
By applying the recording voltage (Vej) to the recording electrode 3,
A strong electric field is generated between the recording electrode 3 and the counter electrode 11, and the charged toner particles 10 fly to the recording paper 12 as the ink 7 together with the liquid carrier from the tip of the recording electrode 3.

Inside the cavity 4, as described above, the carrying electrode 9 is provided at a position substantially facing the counter electrode 11 with the opening 2 as the center, and the carrying electrode 9 is the same as the toner particles 10. A polarity voltage (Vep) is applied. As a result, an electric field is generated between the carrying electrode 9 and the counter electrode 11, and the toner particles 10 are electrophoresed to cause the openings 2
Direction, that is, to the tip of the recording electrode 3. By this operation, not only the flow of the ink 7 but also the toner particles 1
It becomes possible to carry out 0, and the ink 7 can be supplied to the tip portion of the recording electrode 3 without the ink as described in the prior art flowing out from the ink supply tube.

FIG. 4 is a diagram for explaining the recording electrode 3.
The plurality of recording electrodes 3 are formed as follows. That is, first, the thickness is 10 to 50 on the plate-shaped insulating base material 13.
A copper film having a thickness of μm is adhered with an adhesive, a photoresist layer is formed thereon by coating, and the photoresist layer is exposed through a mask having a predetermined electrode pattern.

Next, the exposed photoresist layer is developed to form a photoresist pattern for the recording electrode 3, and this is etched to form a stripe-shaped electrode pattern corresponding to the recording electrode 3. In this case, the individual electrode patterns are formed so as to be electrically independent.

The insulating base material 13 is removed from the lower side of the tip of the recording electrode 3 in advance, and an auxiliary material that melts in a solvent is embedded instead. By melting this auxiliary material with a solvent after forming the recording electrode, the tip of the recording electrode 3 has a structure protruding from the insulating base material 13.

A plurality of recording electrodes 3 thus formed
Are connected to driving ICs (integrated circuits) 14 provided on the insulating base material 13, respectively. Driving IC 14
Is for selectively driving the recording electrodes 3 individually according to recording information, and is connected to a recording head drive circuit described later.

FIG. 5 is a diagram for explaining the operation of this embodiment. That is, since a predetermined potential is applied to the recording electrode 3 and the carrying electrode 9 during the recording operation, the toner particles 10 behave as described with reference to FIG. After the recording operation is completed, the potentials of the recording electrode 3 and the transport electrode 9 become the ground potential, so that the inside of the cavity 4 becomes the same potential.
The toner particles 10 in the ink 7 have a particle size of 0. It has a specific gravity of several μm to a little less than 10 μm and is heavier than the liquid carrier. Therefore, the toner particles 10 settle in the cavity 4. If the toner particles 10 adhere to the tip end portion or the vicinity of the recording electrode 3 due to the precipitation, the following problems occur.

Since the recording electrode 3 corresponds to the recording resolution, it has a width of several tens of μm at present, and the opening 2 also has a width of several hundreds of μm in the height direction. If the toner particles 10 adhere to this, the flow of the ink 7 is obstructed, the ink 7 cannot be stably supplied to the tip portion of the recording electrode 3, the recording characteristics change, and the ink 7 does not fly.

However, in this embodiment, since the ink recovery hole H2 to which the recovery pipe 6 is connected is located at the lowest point in the gravity direction of the cavity 4, the precipitated toner particles 1
0 easily flows into the recovery pipe 6. Further, the inclined surface 4b on which the recording electrode 3 is installed has an inclination such that the tip of the recording electrode 3 faces upward in the gravity direction of the cavity 4, so that the toner particles 10 that settle are deposited on the tip of the recording electrode 3. It easily flows into the ink recovery hole H2 without adhering to the ink. Further, the toner particles 10 are settled on the upper side of the regulating member 8 provided in the cavity 4, but the toner particles 10 settled there hardly affect the conveyance of the ink 7 and the toner particles 10, and the recording characteristics are It does not change.

FIG. 6 shows an example of connection between the ink supply means, the ink recovery means and the recording head 1. The ink contained in the ink supply tank 17 is supplied from the supply pipe 5 through the tube 19 by the ink supply pump 18 into the cavity 4 of the recording head 1 through the ink supply hole H1. An inlet side of an ink recovery pump 20 is connected to the recovery pipe 6 via a tube 19, and an outlet side of the ink recovery pump 20 is connected to a recovery tank 22 via the tube 19. A valve 21 is connected in parallel to the ink recovery pump 20.

During the recording operation, the ink recovery pump 20
Is in a non-operating state, and the valve 21 is in an “open” state. Therefore, the excess ink that has not flown from the recording electrode 3 flows into the recovery tank 22 through the path a of the tube 19.

FIG. 7 is a diagram showing another ink supply means and ink recovery means that can be connected to the recording head 1.
The ink is contained in the ink supply / recovery common tank 23 and is supplied to the recording head 1 by the ink supply pump 18.

Similar to FIG. 6, during the recording operation, the ink collecting pump 20 is in the non-operating state and the valve 21 is in the “open” state. Therefore, the excess ink that has not flown from the recording electrode 3 flows into the ink supply / recovery common tank 23 through the path a of the tube 19. Ink supply
The recovery common tank 23 has a fin 24 for stirring the ink.
Is provided, and the fin 24 is rotated by a motor 25. By doing so, it is possible to stir and reuse the excess ink that did not fly.

FIG. 8 shows a control unit for controlling the operation of this apparatus. That is, the CPU (Central Processing Unit) 41 controls the operation of the entire apparatus according to the control program stored in the ROM (Read Only Memory) 42. The RAM (random access memory) 43 has an interface (I
/ F) 44, and the image information to be recorded, which is input via the (F) 44, is stored. Further, a recording operation start command and an ink recovery instruction command sent from a host device (not shown) connected to the interface 44 are sent to the CPU via the interface 44.
41.

When the CPU 41 receives an ink recovery instruction command, for example, when a timer (not shown) counts a predetermined time and does not receive a recording operation start command within a predetermined time, the ink recovery as described above is performed. Perform an action
The ink 7 is collected from the inside of the cavity 4.

The CPU 41 has the recording head 1
Recording head drive circuit 45 that sends a drive signal to the driving IC 14, a conveyance motor driver 47 that drives a conveyance motor 46 that conveys the recording paper 12, and an ink supply pump driver 48 that drives the ink supply pump 18. ,
An ink recovery pump driver 49 that drives the ink recovery pump 20 and a valve driver 50 that drives the valve 21 are connected, and these are drive-controlled as necessary.

The ink collecting operation in this structure will be described. For example, as shown in FIG. 6, assuming that the ink supply means and the ink recovery means are connected to the recording head 1, the ink recovery pump 20 is inactive during the recording operation, and the valve 21 is " It is in the "open" state. Therefore, the excess ink 7 that has not flown flows into the recovery tank 22 through the path a of the tube 19.

When the recording operation is completed and the command for performing the recording operation for a predetermined time is not executed, or when the command for ending the recording operation of the apparatus is executed immediately after the recording operation is completed, the following operation is performed. . First, the ink supply pump 1
In the non-operating state 8, the valve 21 is in the “closed” state and the ink recovery pump 20 is operated. As a result, the supply of ink to the recording head 1 is cut off, and the ink 7 in the cavity 4 of the recording head 1 is recovered in the recovery tank 22.

At this time, the ink recovery hole H of the cavity 4
Since 2 is at the lowest point in the direction of gravity of the cavity 4, all the ink 7 in the cavity 4 flows into the recovery pipe 6. Further, the inclined surface 4b on which the recording electrode 3 is installed
However, since the tip of the recording electrode 3 is inclined so as to face upward in the gravity direction of the cavity 4, the toner particles 10 do not adhere to the tip of the recording electrode 3 and the ink recovery hole H is formed.
Flow into 2. In this way, when the recording operation is not performed for a long time, the ink 7 does not exist in the cavity 4, so that the precipitation of the toner particles 10 does not occur.

As described above, according to the first embodiment, since the ink recovery hole H2 of the cavity 4 is located at the lowest point in the gravity direction of the cavity 4, the precipitated toner particles 10 flow into the ink recovery hole H2. . In addition, the inclined surface 4b on which the recording electrode 3 is installed has a cavity 4 at the tip of the recording electrode 3.
Since the toner particles 10 are inclined so as to face upward in the gravity direction of the
Does not adhere to the vicinity of.

Further, when the recording operation is completed and the command for performing the recording operation for a predetermined time is not executed, or when the ink recovery command of this apparatus is executed immediately after the recording operation is completed, the ink is collected in the recovery tank. Recovered in 22. At this time, the ink recovery hole H2 of the cavity 4 is
Since it is located at the lowest point in the gravity direction, all the ink 7 in the cavity 4 flows into the recovery pipe 6. Further, since the inclined surface 4a on which the recording electrode 3 is installed is inclined such that the tip of the recording electrode 3 faces upward in the gravity direction of the cavity 4, the toner particles 10 also adhere to the tip of the recording electrode 3. Without flowing into the ink recovery hole H2.

Next, the second embodiment will be described. FIG. 9 shows a main part of the ink jet recording apparatus according to this embodiment. The same parts as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described. That is, a shaft 26 is fixed to the recording head 1 in parallel with the direction in which the recording electrodes 3 are arranged, and the shaft 26 is held by a support member 27. The recording head 1 rotates about the shaft 26. It is movable.
The shaft 26 is connected to a motor 29 via a drive system 28 that transmits a rotational force, and is rotationally driven by the motor 29.

10 and 11 are diagrams for explaining the operation of the ink jet recording apparatus shown in FIG. During the recording operation, as shown in FIG. 10, the recording electrode 3 is in a substantially horizontal direction and faces the counter electrode 11. In this state,
The ink in the cavity 4 reaches the tip of the recording electrode 3 from the opening 2. In addition, as described above, when the recording operation is completed and the command for performing the recording operation for a predetermined time is not executed, or when the operation end command of the apparatus is executed immediately after the recording operation is completed, As shown in FIG. 11, the recording head 1 is rotated so that the recording electrode 3 is substantially vertical and the tip of the recording electrode 3 faces upward. In this state, the ink recovery hole H2 is arranged below the cavity 4. This allows the cavity 4
Even if the toner particles therein are settled, they do not adhere to the tip of the recording electrode 3 or the vicinity of the opening 2, and the ink is recovered in the recovery tank 22 through the ink recovery hole H2.

As described above, according to the second embodiment, when the recording operation is completed and the command for performing the recording operation for a predetermined time is not executed, or immediately after the recording operation is completed, the operation end command of the apparatus is issued. When it is executed, the recording head 1 is rotated so that the recording electrode 3 is substantially vertical and the tip portion of the recording electrode 3 faces upward. Further, in this state, the ink recovery hole H2 is arranged so as to come to the lower side of the cavity 4, so that even if the toner particles in the cavity 4 settle, they are located in the vicinity of the tip of the recording electrode 3 and the opening 2. The ink does not adhere and is collected in the collection tank 22 through the ink collection hole H2.

Next, a third embodiment will be described. FIG. 12 shows a main part of the ink jet recording apparatus according to this embodiment. The same parts as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. Only different parts will be described. That is, the recording electrode 3 is oriented in a substantially vertical direction with the tip end portion facing upward, and the recording electrode 3 and the opening 2 are located substantially at the uppermost point of the cavity 4.
The counter electrode 11 is arranged so as to face the recording electrode 3 and is located above the recording head 1. This arrangement
It is fixed regardless of the recording operation.

During the recording operation, ink is supplied from the ink supply tank 17 into the cavity 4 by the ink supply pump 18, and in the cavity 4, electrophoresis is performed by applying a voltage to the carrying electrode 9. Toner particles 10
Is supplied to the tip of the recording electrode 3. When the recording operation is not performed, the ink recovery hole H2 is arranged below the cavity 4, so that even if the toner particles 10 in the cavity 4 settle, the tip portion and the opening of the recording electrode 3 are formed. The ink does not adhere to the vicinity of No. 2 and is collected in the collection tank 22 from the ink collection hole H2 by its own weight.

In such an arrangement, the ink recording electrode 3
Is supplied to the tip of the substrate by electrophoresis and recording electrode 3
Since the wettability between the ink and the ink is performed, the ink supply capacity is slightly lower than that in the case where the recording electrode 3 is arranged in the horizontal direction, but a mechanism for rotating the recording head 1 is not necessary and the apparatus Can be miniaturized.

As described above, according to the third embodiment, the recording electrode 3 is in the substantially vertical direction regardless of the recording operation.
Since the tip of the recording electrode 3 is arranged to face upward and the ink recovery hole H2 is arranged to be below the cavity 4, the toner particles 1 in the cavity 4 are arranged.
Even if 0 is settled, it does not adhere to the tip of the recording electrode 3 or the vicinity of the opening 2, and the ink is recovered from the ink recovery hole H2 into the recovery tank 22 by its own weight.

[0066]

As described above in detail, according to the present invention, it is possible to prevent the coloring agent particles from adhering to the tip of the recording electrode due to the precipitation of the coloring agent particles in the ink, and to always obtain stable recording characteristics. It is possible to provide an inkjet recording apparatus that can be used.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing a main part of an inkjet recording apparatus according to a first embodiment of the invention.

FIG. 2 is a sectional view schematically showing a main part of the inkjet recording apparatus according to the first embodiment.

FIG. 3 is a diagram illustrating movement of charged toner particles in ink.

FIG. 4 is a diagram illustrating a recording electrode.

FIG. 5 is a diagram for explaining the operation of the first embodiment.

FIG. 6 is a diagram showing an example of connection between an ink supply unit, an ink recovery unit, and a recording head.

FIG. 7 is a diagram showing another example of connection between the ink supply unit, the ink recovery unit, and the recording head.

FIG. 8 is a block diagram schematically showing the configuration of a control unit.

FIG. 9 is a perspective view schematically showing a main part of an inkjet recording apparatus according to a second embodiment of the present invention.

FIG. 10 is a diagram for explaining the operation of the second embodiment.

FIG. 11 is a diagram for explaining the operation of the second embodiment.

FIG. 12 is a configuration diagram schematically showing a main part of an ink jet recording apparatus according to a third embodiment of the invention.

[Explanation of Codes] 1 ... Recording head, 2 ... Opening portion (ejection portion), 3 ... Recording electrode, 4 ... Cavity (ink containing portion), 4a, 4
b ... inclined surface, 5 ... supply pipe, 6 ... recovery pipe, 7 ... ink, 8 ... regulating member, 9 ... transporting electrode, 10 ... toner particles (colorant particles), 11 ... Counter electrode, 12 ... Recording paper (recording medium), H1 ... Ink supply hole, H2 ... Ink collection hole, 17 ... Ink supply tank, 18 ... Ink supply pump, 19 ... Tube,
20 ... Ink recovery pump, 21 ... Valve, 26 ...
… Axis, 28 …… Drive system, 29 …… Motor, 41 …… CP
U, 42 ... ROM, 43 ... RAM, 44 ... Interface, 45 ... Recording head drive circuit, 48 ... Ink supply pump driver, 49 ... Ink collection pump driver, 50 ... Valve driver.

Claims (7)

[Claims] 1. An ink containing portion containing an ink in which charged colorant particles are dispersed in an insulating liquid, and having an ejection portion for ejecting the ink onto a recording medium. An ink supply unit that supplies the ink to the ink storage unit; and the ink storage unit that is provided in the ink storage unit, has a tip portion located in the ejection unit, and is applied with a predetermined recording voltage. A recording electrode for ejecting the ink in the ink storage unit toward the recording medium; and an ink recovery unit for recovering the ink in the ink storage unit from a position that is the lowest point in the gravity direction of the ink storage unit. Inkjet recording device. 2. An ink containing section containing an ink in which charged colorant particles are dispersed in an insulating liquid, and having an ejection section for ejecting the ink onto a recording medium. An ink supply unit that supplies the ink to the ink storage unit; and the ink storage unit that is provided in the ink storage unit, has a tip portion located in the ejection unit, and is applied with a predetermined recording voltage. A recording electrode for ejecting the ink in the portion toward the recording medium; an ink guide means for guiding the excess ink not ejected by the recording electrode to a position which is the lowest point in the gravity direction of the ink containing portion; Ink collecting means for collecting the excess ink guided by the ink guiding means from a position which is the lowest point in the direction of gravity of the ink jet unit. Tsu door recording device. 3. An ink containing section for containing an ink in which charged colorant particles are dispersed in an insulating liquid, and having an ejection section for ejecting the ink onto a recording medium, An ink supply unit that supplies the ink to the ink storage unit; and the ink storage unit that is provided in the ink storage unit, has a tip portion located in the ejection unit, and is applied with a predetermined recording voltage. A recording electrode for ejecting the ink in the portion toward the recording medium, an ink guide means for guiding the excess ink not ejected by the recording electrode to a position which is the lowest point in the gravity direction of the ink containing portion, and a non-recording time. An ink collecting unit that operates and collects the excess ink guided by the ink guiding unit from a position that is the lowest point in the gravity direction of the ink containing unit. An ink jet recording apparatus according to symptoms. 4. An ink containing section for containing an ink in which charged colorant particles are dispersed in an insulating liquid, and having an ejection section for ejecting the ink onto a recording medium, An ink supply unit that supplies the ink to the ink storage unit; and the ink storage unit that is provided in the ink storage unit, has a tip portion located in the ejection unit, and is applied with a predetermined recording voltage. A recording electrode for ejecting the ink in the part toward the recording medium, an ink guide means for guiding the surplus ink not ejected by the recording electrode to a position which is the lowest point in the gravity direction of the ink containing part, and an ink recovery instruction And an ink collecting unit that operates when there is an ink, and collects the excess ink guided by the ink guiding unit from the position that is the lowest point in the gravity direction of the ink containing unit, An ink jet recording apparatus characterized by comprising. 5. An ink containing section for containing an ink in which charged colorant particles are dispersed in an insulating liquid, and having an ejection section for ejecting the ink onto a recording medium, An ink supply unit that supplies the ink to the ink storage unit; and the ink storage unit that is provided in the ink storage unit, has a tip portion located in the ejection unit, and is applied with a predetermined recording voltage. A recording electrode for causing the ink in the part to fly toward the recording medium, and the recording electrode provided in the ink containing part,
A front end of the recording electrode faces upward in the gravity direction of the ink containing portion, and a rear end of the recording electrode is inclined so as to face the gravity direction of the ink containing portion; An ink jet recording apparatus comprising: an ink collecting unit that collects the ink in the ink containing portion from a lower point. 6. An ink containing portion containing an ink in which charged colorant particles are dispersed in an insulating liquid, and having an ejection portion for ejecting the ink onto a recording medium, An ink supply unit that supplies the ink to the ink storage unit, and the tip end portions that are provided inside the ink storage unit and are linearly arranged side by side within the discharge unit, and each have a predetermined recording voltage selectively. When applied, the plurality of recording electrodes that cause the ink in the ink containing portion to fly toward the recording medium, and the tip portions of the ejection portion and the recording electrodes face upward in the gravity direction during non-recording, and when recording, Rotating means for rotating the ink containing portion such that the ejection portion and the tip portions of the recording electrodes face the direction orthogonal to the direction of gravity, and the ejection portion and the tip portions of the recording electrodes. An ink jet recording apparatus comprising: an ink collecting unit that collects ink in the ink containing portion from a position that is the lowest point in the gravity containing direction of the ink containing portion when facing upward in the gravity direction. . 7. A position where an ink containing a dispersion of charged colorant particles in an insulating liquid is accommodated, and an ejection portion for ejecting the ink onto a recording medium is the uppermost point in the gravity direction. And an ink supply unit for supplying the ink to the ink storage unit, the ink storage unit being provided in a vertical state in the ink storage unit, and having a tip portion located in the ejection unit and a predetermined recording When a voltage is applied, the ink in the ink containing portion is ejected toward the recording medium, and the ink in the ink containing portion is recovered from the lowest position in the gravity direction of the ink containing portion. An ink jet recording apparatus comprising: an ink collecting unit.