JPH1086381A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the adhesion of a colorant to an electrode part even if the canon. of the colorant is high by stirring ink in an ink jet recording apparatus using ink prepared by dispersing a colorant component in an insulating solvent. SOLUTION: An ink holding part 5 holding ink 4 prepared by dispersing a colorant component in an insulating solvent, the recording electrode 1a arranged on the head substrate 1b in the ink holding part 5 in order to fly the colorant component in the ink 4 by electrostatic force and the stirring electrode 3 formed on the surface on the side of the ink 4 of the upper substrate 2a arranged on the surface opposed to the recording electrode 1a are provided and, by applying control voltage such that the relation of potential between respective electrodes is reversed at a constant cycle to the stirring electrode 3 from a stirring electrode control circuit 60, the ink 4 is stirred by the force of an electric field.

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, and more particularly to a method for concentrating a colorant component in a liquid ink by a force from an individual electric field generated by a voltage applied to individual electrodes in an array. The present invention relates to an ink jet recording apparatus having a slit-shaped nozzle that flies as a droplet.

[0002]

2. Description of the Related Art Conventionally, there has been known an ink jet printer which forms recording dots by flying liquid ink onto a recording medium. Such an ink jet recording apparatus has advantages in that it has less noise and does not require processing such as development and fixing as compared with other recording methods, and thus has been attracting attention as a plain paper recording technique.

[0003] To date, a number of ink jet recording systems have been proposed. For example, a method of causing ink droplets to fly at the above-mentioned pressure generated by the heat of a heating element is disclosed in JP-B-56-9429 and JP-B-61-599.
No. 11, for example. On the other hand, a method of causing ink droplets to fly by a mechanical pressure pulse generated by a piezoelectric body is disclosed in Japanese Patent Publication No. 53-12138.

In particular, the techniques disclosed in the above-mentioned patent publications are typical as a multi-nozzle type that records a plurality of dots by arranging a plurality of dots in parallel. The recording heads proposed by these techniques are practically used as serial scan type heads which are mainly mounted on a carriage and repeat scanning in a direction perpendicular to the recording paper conveyance direction.

On the other hand, a system in which multi-nozzles are arranged on a long recording head having the same size as the recording paper instead of mounting the recording head on a carriage can reduce the number of movable parts and increase the recording speed. . However, it is not easy to actually produce such a line scanning type recording head.

In other words, in a system in which nozzles are multiplied,
Local concentration of the ink is likely to occur due to evaporation and volatilization of the solvent. For this reason, individual thin nozzles arranged corresponding to the resolution required for recording cause clogging.
In particular, in the method using the pressure of steam, thermal
Alternatively, adhesion of insoluble matter due to a chemical reaction or the like becomes a problem. On the other hand, in the method using the pressure of the piezoelectric body, a complicated structure such as an ink flow path easily causes clogging.

[0007] However, due to technological innovation,
With a serial scan type recording head that requires hundreds of tens of nozzles, it is not so difficult to reduce the frequency of clogging, but a line scanning type structure that arranges thousands of nozzles In the case of (1), clogging of the nozzle still occurs at a quite high probability, which is a serious problem in securing reliability.

On the other hand, in the case of the ink jet system, there is a problem that it is very difficult to increase the resolution. In other words, it is very difficult to generate a droplet diameter of 20 μm or less in the case of using the vapor pressure. 20μ diameter
m droplets having a diameter of 50 μm on the recording surface
It is very difficult to realize a resolution higher than this. Further, in the case of the method using the pressure of the piezoelectric body, there is a problem that it is difficult to produce a high-resolution head due to limitations in processing technology due to its complicated structure.

In order to overcome the above-mentioned problems, a method has been proposed in which a voltage is applied to a thin-film electrode array, and ink or a colorant component in the ink is caused to fly from the ink liquid surface by using the force of static electricity. Have been. For example, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open No. 9-62024 and Japanese Patent Application Laid-Open Publication No. Sho 56-4467 have been proposed. Japanese Patent Publication No. 502218 is proposed.

[0010] These methods do not require a nozzle for each individual dot or a partition for an ink flow path, and can employ a slit-shaped nozzle or a nozzle-less structure, which is a major obstacle in forming a recording head into a line. It is an effective method for preventing and recovering from clogging. In particular, the method of increasing the concentration of a colorant and using an ink containing a charged colorant component to fly ink droplets with a very small diameter can stably generate and fly, so high resolution can be achieved. Are suitable.

FIG. 19 is a schematic structural view of such a conventional ink jet recording apparatus. In particular, a liquid ink in which a charged coloring material is mixed in a solvent is used, and the ink is discharged in a state where the concentration of the coloring material is increased. The method of flying is illustrated.

As shown in the drawing, a recording head 1 has an ink holding portion 5 composed of a substrate and an upper lid,
The ink 4 containing the charged colorant is supplied from an ink tank (not shown) in the direction of the arrow.

On the substrate of the recording head 1, a large number of recording electrodes 1a are formed in an array and are connected to a control circuit 50. The control circuit 50 is supplied with power from a recording power supply 51.

On the other hand, an auxiliary electrode 13 for moving the colorant toward the tip of the recording head 1 is provided on the upper cover of the recording head 1.
The auxiliary electrode 13 has a power supply 1 for the auxiliary electrode.
4 are connected.

The recording medium 12 is kept in close contact with the recording drum 11 connected to the ground potential.
Passing around in the direction indicated by the arrow.

The ink 4 contains a charged coloring agent,
As an example of such an ink, a toner for liquid development used in a liquid development type electrophotographic recording apparatus is generally known. Here, the coloring agent contained in the ink 4 is
For example, it is assumed that it is positively charged.

Now, the recording electrode 1a and the auxiliary electrode 13
Bias voltages having different potentials, for example, 1.4 k each
V and 2.0 kV are applied, and the charged colorant moves by an electric field formed between these electrodes.

In this case, the auxiliary electrode 1 is more than the recording electrode 1a.
Since the potential of No. 3 is set high, the charged colorant concentrates near the recording electrode 1a, and the density is increased. When a pulsed signal voltage is supplied in such a state, the concentrated colorant receives a repulsive force from the recording electrode 1a and a suction force from the recording drum 11, and is discharged from the tip of the recording electrode 1a. The ejected ink droplet 4a is applied to the recording electrode 1a.
The recording medium 11 flies in an electric field between the recording medium 11 and the recording medium 11 and flies on the recording medium 12 to form an image.

In such an ink jet recording apparatus,
An electric field formed between the recording electrode 1a and the auxiliary electrode 13 causes the colorant in the ink holding unit 5 to be sent to the front end. On the other hand, when the direction of the electric field is reversed, the colorant is conversely changed. The ink can be collected in the ink holding unit 5. In other words, one of the features is that it is possible to control the inflow and outflow of the colorant from the ink holding unit 5 according to the state of the apparatus.

However, when the colorant is collected, the colorant concentration inside the ink holding unit 5 increases, so that the colorant may adhere to the inside of the ink holding unit 5. As described above, when the colorant adheres, the amount of the colorant that can be supplied decreases, and the attached colorant may interfere with the colorant to be moved, which makes it difficult to supply the next colorant. Become.

Further, even when the apparatus is left for a long period of time with the power supply turned off, the coloring material adheres easily to the inside of the ink holding unit 5, and the supply capacity of the coloring material when the power supply is turned on is greatly increased. However, there has been a problem that the reliability of the apparatus has been reduced.

[0022]

As described above,
In a conventional ink jet recording apparatus, in a method in which an ink droplet is caused to fly by the force of an electric field, an auxiliary electrode 13 is provided in addition to the recording electrode 1a in order to maintain the ejection continuity of the ink droplet. Since the configuration is such that the inflow and outflow of the coloring material is controlled, the coloring material easily adheres to the inside of the ink holding portion 5 when the concentration of the coloring material inside the ink holding portion 5 increases. For this reason, there is a problem that the supply of the colorant is likely to be hindered. On the other hand, when the power supply of the apparatus is turned off, there is a high possibility that the coloring material adheres to the inside of the ink holding unit 5, and there is a problem that the ink supply capacity is insufficient at the time of restarting.

The present invention solves the above-mentioned problems of the prior art, and when the coloring material is collected inside the ink holding portion, the coloring material is applied to the electrode inside the ink holding portion and the insulator near the electrode. It is an object of the present invention to provide an ink jet recording apparatus capable of satisfactorily supplying ink by optimizing the state of the ink when the power is turned on again even if the power is turned off and left for a long time without adhesion. Aim.

[0024]

In order to achieve the above object, the present invention provides an ink jet recording apparatus as claimed in claim 1, wherein said ink holding means holds an ink in which a colorant component is dispersed in an insulating solvent. An ink jet recording apparatus comprising: a recording electrode disposed in an ink holding means for causing a colorant component in the ink to fly by electrostatic force; and a stirring means disposed in close proximity to the recording electrode and stirring the ink. An apparatus is provided.

According to another aspect of the present invention, there is provided an ink jet recording apparatus, comprising: an ink holding unit for holding an ink in which a colorant component is dispersed in an insulating solvent; A recording electrode for causing the colorant component in the ink held by the ink jet to fly by electrostatic force, a transport electrode for transporting the ink in the ink holding unit in the supply direction and the collection direction, and at least one electrode in proximity to the recording electrode. The present invention is to provide an ink jet recording apparatus comprising: a stirring unit that is disposed at a location and stirs ink.

In order to achieve the above object, the present invention provides an ink jet recording apparatus as set forth in claim 7, wherein said ink holding means holds ink in which a colorant component is dispersed in an insulating solvent, and said ink holding means. A recording electrode that causes the colorant component in the ink held by the ink to fly by electrostatic force, an area of an electrode group that transports the ink in the ink supply means in the supply direction and a recovery direction, and an area of the electrode group that agitates the ink. And a common means for transport and agitation.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing embodiments of the present invention with reference to the drawings, the present invention will be schematically described.

The ink jet recording apparatus of the present invention uses a liquid ink in which a colorant component is dispersed in an insulating solvent, and the liquid ink or the colorant component in the liquid ink is caused to fly by electrostatic force. The ink is agitated as necessary by an ink holding unit for holding the ink, and a stirring means for stirring the ink provided inside the ink holding unit or in the vicinity of the ink holding unit to improve the state of the ink. Configure to keep. Especially,
When the stirring means is a stirring electrode, ink is stirred by the electric field by applying a voltage to the set of stirring electrodes so that a potential difference is generated such that the relationship between the potential levels is reversed at regular intervals. I do.

As a result, by forming a state in which the liquid ink always moves, the liquid ink can be agitated and the adhesion of the colorant can be prevented.

The ink may be stirred using an ultrasonic generator instead of the stirring electrode. In this case, the agitating action can be exerted on the ink without directly contacting the ink.

The stirring electrode and the ultrasonic wave generating means can be provided at a plurality of locations. As a result, it is possible to prevent the colorant from adhering to the entire apparatus.

In the structure including the stirring electrode, when the stirring electrode is provided adjacent to the recording electrode for ejecting the ink droplet, the average voltage of the stirring electrode is higher than the average voltage of the recording voltage when supplying the ink. At the time of ink recovery, driving is performed so as to be lower than the average voltage of the recording electrodes. As described above, the movement of the colorant in the ink can be controlled by controlling the potential relationship between the stirring electrode and the recording electrode.

Further, in the structure having the stirring electrode, when a recording electrode for discharging ink droplets and an ink transport electrode for transporting ink near the recording electrode are provided, the stirring electrode is disposed adjacent to the ink transport electrode. When the electrode is provided, the stirring electrode is driven so that the average voltage of the stirring electrode is higher than the average voltage of the ink transport electrode during ink supply and lower than the average voltage of the ink transport electrode during ink recovery. As described above, when controlling the potential relationship between the stirring electrode and the transport electrode, not only the movement of the color material in the ink can be controlled, but also the movement of the color material by the transport electrode is not hindered.

The ink transport electrode and the stirring electrode may be constituted by a common electrode. In this case, the common electrode is driven so that a part of the common electrode performs a conveying action and another part of the common electrode performs a stirring action, so that a structure in which the action boundary, that is, a combination of actions can be freely changed. . As a result, it is not necessary to provide a special stirring electrode for stirring the ink.

In a structure having at least a stirring electrode provided for stirring the ink or a stirring means using an ultrasonic wave generating means, a density detecting means is installed near the stirring means, and the stirring is performed based on information from the density detecting means. The control signal to the means may be adjusted.

The density detecting means may be provided at a plurality of locations.

As described above, by providing the density detecting means, by observing the actual state of the coloring material, it is possible to verify the presence or absence of the coloring material or the effect of the stirring action, and to use the information as the stirring means. The control can be fed back to the control, so that the adhesion can be reliably and reliably prevented. Further, by providing a plurality of density detecting means, it is possible to further enhance the reliability.

The density detecting means is composed of a light emitting section and a light receiving section, and a part or all of the ink holding section is provided with light transmissivity, and the density detecting section is made to transmit light through the ink holding section. The density of the ink may be detected based on this. Alternatively, a part or all of the stirring means may have light transmittance, and the density detecting means may detect the density of the ink based on the light transmittance through the stirring means.

On the other hand, the concentration detecting means may be constituted by a plurality of electrodes and a resistance measuring means for measuring a resistance value between the electrodes. In this case, it is not necessary to provide a particularly large space for density detection. Furthermore, the electrode for stirring the ink and the electrode for detecting the density can be constituted by the same electrode, and in this case, there is an advantage that it is not necessary to provide an electrode for the specific density detection. is there.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus according to a first embodiment of the present invention.

As shown in the drawing, the recording head comprises a head substrate 1b on which a recording electrode 1a for discharging ink droplets 4a is disposed, and an upper substrate 2 provided above and opposed to the head substrate 1b.
a and a lower substrate 2b provided to face downward. A control circuit 50 connected to a recording power supply 51 is connected to the recording electrode 1a.

An ink holding portion 5 is formed between the upper substrate 2a and the head substrate 1b, and between the lower substrate 2b and the head substrate 1b, in which the ink 4 can freely flow. It is kept in a movable state. For this purpose, the upper substrate 2a and the lower substrate 2b are both arranged from the head substrate 1 via a spacer of about 500 μm.

A plurality of stirring electrodes 3 for stirring the colorant in the ink holding section 5 are formed on the surface of the upper substrate 2a in contact with the ink 4, and the stirring electrodes 3 are connected to a stirring power supply 61. The control circuit 60 is connected.

The ink 4 to be filled in the recording head is formed by dispersing a positively-charged colorant containing a charge control agent and a binder in a colloidal form in an insulating solvent having a resistivity of 10 ⁸ Ωcm or more. And usually have a positive potential.

The ink 4 is once filled in the ink holding section 5 through the ink supply path 7a, and then supplied to the tip of the head, and has a meniscus shape as shown in FIG. The ink 4 around this is supplied to the stirring electrode 3
During the printing operation, the colorant is concentrated, and the colorant density increases.

At the forefront of the head, ink droplets 4a having a higher colorant concentration are ejected, and the ink 4 that has not contributed to the ejection circulates around the head tip and moves between the head substrate 1b and the lower substrate 2b. And flows into the ink recirculation mechanism 8 connected to the head.

Since the colorant concentration of the ink 4 in the ink recovery flow path 7b is relatively low, the colorant concentration is adjusted by the ink concentration adjusting unit 9 including the ink tank provided in the ink recirculation mechanism 8. Optimize. Further, a pump 10 is provided in the ink recirculation mechanism 8 in order to optimize the state of the meniscus in the opening 6 and control the overall flow of the ink 4.

In front of the head, a grounded recording drum 1
1 face each other with a gap of 500 μm or less, and a recording medium 12 for recording an image point is wound around the surface.

FIG. 2 is an enlarged perspective view showing the tip of the ink jet head.

As shown in the figure, the head substrate 1b
Is formed of a material having a low dielectric constant and a high strength such as polyimide, glass epoxy resin, phenol resin, and Teflon having a thickness of about 50 μm, and has a rectangular surface made of Cu having a thickness of about 18 μm on its surface. A recording electrode 1a having a shape is formed in a stripe shape. The back surface of the upper substrate 2a is also formed of the same material as that of the head substrate 1b, and a rectangular stirring electrode 3 made of Cu having a thickness of about 18 μm is formed on the surface thereof in a stripe shape. The head substrate 1b protrudes from the tip of the upper substrate 2a by about 1 mm, so that the thickness of the ink 4 at the tip of the head substrate 1b can be set thin.

Next, the operation of the above configuration will be described.

First, the control circuit 50 applies a drive waveform as shown in the explanatory diagram of FIG. 3 to the recording electrode 1a of the head substrate 1b. That is, the plurality of recording electrodes 1a
Is divided into even-numbered and odd-numbered systems.
A DC bias of about 4 kV from the recording power supply 51 and continuous pulses 52a and 52b whose phases are shifted from each other by a half cycle are superimposed and applied. When such a waveform is given, a potential gradient is generated between adjacent electrodes, the direction of which is reversed at regular intervals, and the colorant always moves in the direction of lower potential. The color material reciprocates between the recording electrodes 1a and is constantly stirred. When the pulse signal 53 based on the image signal is applied to the recording electrode 1a at the moment when the potential becomes low, the ink droplet 4a is ejected.

On the other hand, a drive waveform as shown in FIG. 4 is applied to the stirring electrode 3 by the stirring electrode control circuit 60. That is, the plurality of stirring electrodes 3 are divided into even-numbered and odd-numbered systems, and a DC bias from the stirring power supply 61 and continuous pulses 62a and 62b whose phases are shifted by a half cycle from each other are applied in a superimposed manner. When such a waveform is given, a potential gradient occurs in which the direction is reversed at regular intervals between adjacent electrodes, and the colorant always moves in the direction of lower potential. During this period, the colorant reciprocates and is constantly stirred.

During the recording operation, the colorant in the ink 4 needs to be supplied onto the recording electrode 1a.
Is set higher than the average voltage of the recording electrode 1a. For example, the DC bias of the recording electrode 1a is Vpb,
The amplitude of the continuous pulses 52a, 52b is Vpp,
In the case where the DC bias to Vsb is Vsb, if the adjustment is made so that the relationship of Vsb ≧ Vpb + Vpp (1) is satisfied, it is possible to surely supply the colorant.

Conversely, when the recording material is at rest or when the coloring material attached to the recording electrode 1a is to be removed, the average voltage of the recording electrode 1a is set lower than the average voltage of the stirring electrode 3.
For example, when the amplitude of the continuous pulses 62a and 62b of the stirring electrode 3 is set to Vsp, the operation is performed such that the following relationship is established. Vpb ≧ Vsb + Vsp (2) When the relationship of the average voltage is reversed, the coloring material in the ink moves in the direction of the ink holding unit 5, so that the coloring material becomes thinner at the head end,
Components other than the colorant, for example, an insulating solvent are mainly retained. In other words, the coloring agent is less likely to adhere to the head end. Conversely, although the colorant concentration is increasing in the ink holding unit 5, the colorant always moves between the electrodes by the stirring electrode 3 and is agitated, so that the possibility that the colorant adheres is reduced. .

The setting of the voltage is described in (1) above.
The formula is not limited to the formula (2), and the DC bias of the stirring electrode 3 and the amplitude or the duty ratio of the continuous pulses 62a and 62b may be adjusted in consideration of the level difference at the average voltage.

As described above, by disposing the stirring electrode 3 for stirring the coloring material of the ink 4 in the ink holding portion 5, the coloring material is particularly recovered and the concentration of the coloring material in the ink holding portion 5 is increased. Also in this case, it is possible to prevent the colorant from adhering to the ink holding unit 5.

When the stirring electrode 3 is provided close to the recording electrode 1a, by controlling the potential relationship between the stirring electrode 3 and the recording electrode 1a, it is possible to control the colorant concentration at the tip of the head. Thus, the colorant can be supplied smoothly.

In this embodiment, the stirring electrode 3 is
Since the coloring material is formed into a plurality of colors for the purpose of stirring, the pitch, the number, and the like of the stirring electrodes 3 do not always need to match the recording electrodes 1a, and further, the electrode forming direction does not match the recording electrodes 1a. As shown in the plan view of FIG.
A plurality of stirring electrodes 3 may be formed at a certain distance along the extending direction of the electrodes, regardless of whether they are arranged in an oblique direction or in a curved shape as shown in the plan view of FIG. Thus, the same effect can be obtained.

In the first embodiment, the stirring electrode 3 is formed on the surface of the upper substrate 2a on the side of the ink 4, but may be arranged on the outer surface as shown in a partial perspective view of FIG. In this way, the ink 4 does not come into contact with the stirring electrode 3, so that the coloring material of the ink 4 can be prevented from adhering to the stirring electrode 3. However, in this case, since the electric field acts on the colorant via the thickness of the upper substrate 2a, the influence of the electric field is reduced. Therefore, the upper substrate 2
It is necessary to suppress the thickness of a to about 50 μm or less so that the electric field can be sufficiently applied.

When the upper substrate 2a is made thinner, the mechanical strength of the upper substrate 2a may be reduced. However, a material having high strength may be used, or as shown in a partial perspective view of FIG. By arranging another reinforcing member 2c on the stirring electrode 3, it is possible to compensate for the insufficient strength.

Incidentally, for the upper substrate 2a, a hard material such as Si can be used in addition to the material usually used for the flexible substrate. For example, when Si is used as the substrate, the stirring electrode 3 can be formed in a thin film, so that the number of grooves and steps formed by the electrode is reduced, and the coloring agent is less likely to adhere. In addition, there is an advantage that an arbitrary electrode pattern can be easily formed and a mechanical strength can be ensured because the material is harder.

In the explanatory diagram of FIG. 4, a continuous pulse 62a is applied to the stirring electrode 3 by applying a DC bias from the stirring power source 61,
Although the case where a signal in which 62b is superimposed is given is illustrated,
Even if a sine wave is applied instead of the continuous pulses 62a and 62b, the desired effect can be achieved without changing the stirring effect.

The ink stirring means of this embodiment may be installed at a plurality of locations as long as the location where the ink 4 exists. For example, an ink supply path 7 a serving as a flow path of the ink 4 in an ink tank for replenishing the ink 4,
The inside of the ink recovery channel 7b is considered.

In particular, when the apparatus is left for a long time, the adhesion of the colorant is likely to occur.
When the stirring operation is performed at a plurality of locations, it is possible to quickly return the ink 4 to a normal state as a whole of the apparatus. Embodiment 2. FIG. FIG. 9 is a partially enlarged cross-sectional view of the ink jet recording apparatus according to the second embodiment of the present invention, and particularly shows an enlarged view of a head end portion.

As shown in the drawing, a piezoelectric body 22 is disposed on the upper part of the recording head, an ultrasonic generating individual electrode 23 is disposed on the upper surface thereof, and an ultrasonic generating common electrode 21 is disposed on the lower surface thereof. Be placed. Ultrasonic generating common electrode 21
A sound wave interference layer 20 is interposed between the ink and the ink holding unit 5.
The sound wave interference layer 20 is a substance also serving as an acoustic matching layer between the piezoelectric body 22 and the ink 4, and is made of, for example, glass.

The piezoelectric member 22 is formed on the entire surface or in a strip shape by means of a material such as ZnO or PLZT which can control the thickness by sputtering or the like, and the ultrasonic generating individual electrode 23 and the ultrasonic generating common electrode are formed on the upper and lower surfaces thereof. 2
1 is formed. These ultrasonic generating individual electrodes 23
The ultrasonic generating common electrode 21 is connected to an ultrasonic generating circuit 24 receiving a bias voltage from a DC power supply 25.

Next, the operation of the above configuration will be described.

When generating ultrasonic waves, the ultrasonic generating common electrode 2
1 and the ultrasonic generating individual electrode 23, the frequency is several MHz.
A drive signal having a voltage of several tens of volts to several hundreds of volts at a frequency of several hundred MHz is applied. As a result, an ultrasonic wave is generated at the ultrasonic generating common electrode 21 and acts on the ink 4 inside the ink holding unit 5 through the sound wave interference layer 20, so that the colorant is agitated and the adhesion of the colorant can be prevented. .

In order to form an electric field which influences the movement of the colorant between the ultrasonic generating common electrode 21 and the recording electrode 1a, it is necessary to apply a voltage in consideration of the relationship with the voltage of the recording electrode 1a. There is. That is, the voltage of the ultrasonic generating common electrode 21 is set higher than the average voltage of the recording electrode 1a when supplying the colorant, and the voltage of the ultrasonic generating common electrode 21 is set lower than the average voltage of the recording electrode 1a when collecting the colorant. There is a need to. Therefore, it is necessary to supply a DC bias from the DC power supply 25 to both the ultrasonic generating common electrode 21 and the ultrasonic generating individual electrode 23. The potential relationship in this case is, for example, assuming that the DC bias to the ultrasonic generating common electrode 21 is Vub, the relationship of Vub ≧ Vpb + Vpp (3) when supplying the colorant, and the relationship of Vub ≦ Vpb (4) when collecting the colorant. It is necessary to adjust to satisfy. As a result, the moving direction of the colorant can be reliably controlled. Note that the method of setting the voltage is not limited to the relations of the expressions (3) and (4), and it is needless to say that the voltage can be adjusted in consideration of the difference in the average voltage.

As in this embodiment, when ultrasonic waves are used as the ink stirring means, the ultrasonic generating common electrode 21 and the ultrasonic generating individual electrode 2 which are the electrodes for generating ultrasonic waves are used.
Since the ultrasonic wave can be applied to the ink 4 without bringing the ink 3 into contact with the ink 4, the ink 4 can be efficiently stirred without worrying about the adhesion of the colorant to the electrode.

Further, since the structural material formed by the sound wave interference layer 20, the ultrasonic wave generating common electrode 21, the piezoelectric body 22, and the ultrasonic wave generating individual electrode 23 is put in the upper lid of the ink holding portion 5, the mechanical strength is increased. Can be enhanced.

In the embodiment shown in FIG. 9, one piezoelectric body 22 is used as the ultrasonic wave generating means,
However, as shown in the partial enlarged cross-sectional view of FIG. 10, the use of the individually divided piezoelectric bodies 22 makes it possible to more reliably and finely agitate each region. become able to.

The ultrasonic wave generating means of this embodiment may be installed at a plurality of places as long as the place where the ink 4 exists. For example, an ink supply path 7 a serving as a flow path of the ink 4 in an ink tank for replenishing the ink 4,
The inside of the ink recovery channel 7b is considered.

In particular, when the apparatus is left for a long time, the adhesion of the coloring material is likely to occur.
When the stirring operation is performed at a plurality of locations, it is possible to quickly return the ink 4 to a normal state as a whole of the apparatus.

As described above, according to the ink jet recording apparatus of this embodiment, since the ultrasonic wave is used as the stirring means, a sufficient stirring action can be exerted without bringing the stirring source into contact with the ink. Therefore, there is no colorant attached to the electrode, and the strength can be increased.

Further, the ultrasonic wave generating source can be provided at a plurality of positions in the head, and it is possible to maintain the ink state satisfactorily as a whole, especially when the apparatus is left for a long time. In this case, the ink can be quickly returned to a normal state. Embodiment 3 FIG. FIG. 11 is a partially enlarged cross-sectional view of an ink jet recording apparatus according to a third embodiment of the present invention, and particularly is an enlarged view of a head end portion.

As shown in the drawing, an electrode array 30 for transporting the ink 4 is provided on the ink-side surface of the upper substrate 2a, and is formed in a stripe shape perpendicular to the recording electrodes 1a. . A transfer driver circuit 31 is connected to the electrode array 30, and a DC bias is supplied to the transfer driver circuit 31 from a DC power supply 32. The stirring electrode 3 for stirring the ink 4 includes an electrode array 3
0, and is formed here in a stripe shape parallel to the recording electrode 1a.

Next, the operation of the above configuration will be described.

The electrode groups 30a to 30e constituting the electrode array 30 for transporting ink are supplied with a DC bias from the DC power supply 32 and a voltage application position that moves with time as shown in the waveform diagram of FIG. The phase shift controlled three-phase voltage pulse trains φ1, φ2, φ3 are supplied by the transport driver circuit 31.

Here, when the ink 4 is supplied to the tip of the head, the average voltage of the electrode array 30 is set higher than the average voltage of the recording electrode 1a so that an electric field acts toward the tip of the head. As shown in FIG. 12, the phase of the pulse is changed so that the colorant inside moves toward the head tip.
shift. Further, a value equal to or higher than the average voltage of the electrode array 30 is set as an average voltage for the stirring electrode 3 provided in the vicinity of the electrode array 30. This is to prevent the color array from being hindered by the electrode array 30.

Assuming that the direct current bias to the electrode array 30 is Vcb and the pulse amplitude is Vcp, for example, if the voltage is set so as to satisfy both Vpb + Vpp ≦ Vcb (5) Vcb + Vcp ≦ Vsb (6) Can be done. On the other hand, the method of supplying the pulse voltage to the stirring electrode 3 is the same as that of the first embodiment, and the stirring operation is performed in such a state that the potential difference between the adjacent electrodes is always reversed.

When the colorant in the ink 4 is supplied to the tip of the head, it is sufficient to drive the recording electrode 1a such that the relation of the average voltage is as follows: recording electrode 1a <electrode array 30 ≦ stirring electrode 3. 5) Formula,
It is not limited to the expression (6).

Conversely, when the colorant is collected in the ink holding unit 5, the driving is performed in a completely opposite manner to the supply of the colorant. That is, the electrode groups 30a to 30e are driven so as to shift the phase relationship of the pulse shown in FIG. 12 in the opposite direction, and the relationship of the average voltage is such that recording electrode 1a> electrode array 30 ≧ stirring electrode 3. Set. As a result, it is possible to apply an electric field in the direction away from the head end in the ink holding unit 5, and it is possible to smoothly recover the colorant.

By the way, when the ink conveying means is provided near the head end, the color material can be moved in one direction in the ink holding portion 5, but when the color material is collected, the movement is continued. When this is done, the color material just moves away from the head end, and the next time the color material is supplied, the supply distance of the color material becomes longer, and the recording start time is delayed accordingly. In addition, the possibility that the colorant adheres to the destination is increased. On the other hand, when the stirring electrode 3 is provided in the vicinity of the electrode array 30 as in the present embodiment, the coloring material conveyed by the electrode array 30 is stopped at the position of the stirring electrode 3, so that We can respond quickly to supply,
Further, since the coloring agent is constantly stirred, there is no fear of adhering to the electrode. Further, according to the above-described driving method, it is possible to cope with the movement direction of the colorant so as not to hinder the movement direction but to accelerate the movement direction.

In the description of this embodiment, the case where the stirring electrode 3 is used for stirring the ink is mainly described.
It goes without saying that even if the ink agitation is replaced by an ultrasonic wave generating means, the same applies. That is, exactly the same control is possible only by replacing the relationship between the electrode array 30 and the stirring electrode 3 with the relationship between the electrode array 30 and the ultrasonic generating common electrode 21.

As described above, according to the present embodiment, the agitating means is provided adjacent to the ink transport means, so that the ink transport position can be determined and the adhesion of the colorant at the transport destination can be prevented. There is an effect that can be. Embodiment 4. FIG. FIG. 13 is a partially enlarged cross-sectional view of an ink jet recording apparatus according to a fourth embodiment of the present invention, and particularly is an enlarged view of a head end portion.

As shown, the ink 4 on the upper substrate 2a
On the surface on the side, a plurality of function-sharing electrodes 40 having the function of the ink transport electrode and the function of the stirring electrode are formed in a stripe shape perpendicular to the recording electrode 1a. These function-sharing electrodes 40 are controlled by a function-sharing electrode control circuit 41 which is supplied with a DC bias from a DC power supply 42.

In the case of FIG. 13, one of the function-sharing electrodes 40 in the ink transfer area 43a is replaced with the transfer electrode group 40.
a to 40e, and those in the ink stirring area 43b are assigned as stirring electrode groups 40f to 40i. Of course, the function boundary area 43c, which is the boundary between the ink transport area 43a and the ink stirring area 43b, can be arbitrarily moved by the function common electrode control circuit 41.

As described above, the function common electrode 40 is
In the ink transport area 43a assigned as the transport electrode groups 40a to 40e, the ink 4 in the ink holding unit 5 is driven to be supplied or collected by a driving method as shown in FIG.

On the other hand, the function common electrode 40 is changed to the ink stirring area 4 assigned as the stirring electrode groups 40f to 40i.
In 3b, the ink 4 in the ink holding unit 5 is agitated by the driving method as shown in FIG.

The potential relationship between the electrodes in the ink transport area 43a and the ink stirring area 43b is basically the same as that in the third embodiment.
In practice, the operation is performed by adjusting the amplitude of each pulse by the function-sharing electrode control circuit 41.

The function boundary area 43c that determines the boundary between the ink transport area 43a and the ink stirring area 43b is changed as follows.

For example, in the case of colorant recovery,
When a short pause is to be performed after the end of sheet recording until recording of the next sheet, as shown in FIG. 14A, the function boundary area 43c is moved to a position near the head end. As a result, since the ink transport area 43a is narrowed, the moving distance of the colorant for collecting the colorant can be reduced, so that the time until the colorant is supplied at the time of recording the next sheet is shortened. It is possible to

On the other hand, in the case of a long-term suspension, FIG.
As shown in (b), the functional boundary area 43c is moved to a position far from the head end, and the ink transport area 43a is widened to a sufficiently wide range. As a result, the ink transport area 43a can be sufficiently obtained, so that the colorant can be collected to a position sufficiently distant from the head end, and the adhesion of the colorant to the head end can be effectively prevented.

As described above, the function common electrode 40 is divided into the ink transport area 43a and the ink agitation area 43b, each of which is provided with a transport electrode group 40a to 40e and a stirring electrode group 40f.
By allocating as ４０40i, not only the manufacturing becomes easy, but also the arbitrary function can be assigned to an arbitrary electrode depending on the control method by the function common electrode control circuit 41, so that the state of the recording apparatus can be controlled. It is possible to apply the corresponding optimal control, thereby increasing the flexibility of the apparatus and realizing an efficient and highly reliable inkjet recording apparatus.

As described above, according to the present embodiment, when the electric field is used as the stirring means, the ink transport function and the stirring function can be realized by the common electrode, so that the structure of the apparatus is simplified. Thus, by arbitrarily changing the boundary between the transport function part and the stirring function part, there is an effect that control according to the situation becomes possible. Embodiment 5 FIG. FIG. 15 is a partially enlarged cross-sectional view of the ink jet recording apparatus according to the fifth embodiment of the present invention, and is particularly an enlarged view of the head end portion as viewed from the front.

As shown in the figure, the upper substrate 2a
An optical density detecting unit 70 composed of a light transmitting material, for example, glass, and including a light emitting element and a light receiving element is disposed thereon. Then, the optical density detecting section 70 is connected to a stirring electrode control circuit 60 for controlling the stirring electrode 3.

In the configuration described above, the light emitted from the optical density detection unit 70 passes through the upper substrate 2a, is introduced into the ink holding unit 5, and is guided into the ink 4 as incident light 71a. The incident light 71a is then transmitted to the head substrate 1
b, and returns inside the ink 4 as reflected light 71b,
The light again passes through the upper substrate 2a and enters the optical density detection unit 70.

The colorant easily adheres between the stirring electrodes 3 on the upper substrate 2a, and easily adheres between the recording electrodes 1a on the head substrate 1b. As a result, when the colorant adheres, the light transmittance of the upper substrate 2a is greatly reduced, and the light reflectance of the head substrate 1b is significantly reduced. That is, the optical density detection unit 70 determines the degree of colorant adhesion by the reflected light 71.
It can be detected by the intensity of b. By feeding back this detection result to the stirring electrode control circuit 60, it becomes possible to execute stirring control according to the situation inside the ink holding unit 5.

For example, the stirring operation by the stirring electrode 3 is basically performed to prevent the adhesion of the coloring material, and does not need to be operated unless the coloring material is adhered. Therefore, the optical density detecting unit 70 detects the state inside the ink holding unit 5 at regular intervals of a predetermined time, after recording a predetermined number of sheets, or immediately before starting recording after leaving for a long time, so that the colorant adheres. Only if it is determined that
If a pulse is supplied to the stirring electrode 3 by the stirring electrode control circuit 60, the load on the stirring electrode control circuit 60 can be reduced.

Further, the optical density detecting section 70 outputs the reflected light 71
Since the state of adhesion of the colorant can be detected based on the intensity of b, the stirring electrode control circuit 60 can execute the optimum stirring control based on the detection signal from the optical density detection unit 70.

That is, when the state of the stirring control of the stirring electrode 3 is the same, for example, when the stirring electrode 3 is controlled while the bias voltage, the pulse width, the pulse amplitude, etc. are kept constant, it is always possible to adapt to various adhesion conditions of the colorant. Not necessarily. On the other hand, the situation of the stirring control, such as the relationship of the bias potential with the recording electrode 1a and other control electrodes, and the combination of functions, can be changed in various ways. It is possible to create an optimal control situation.

Therefore, the parameter for the stirring operation by the stirring electrode 3 is changed based on the feedback signal from the optical density detection unit 70, and the parameter optimization loop is repeated until the colorant is not adhered. An effective stirring operation can be performed.

For example, the control is such that the adhesion state of the colorant is monitored while gradually increasing the potential difference between the stirring electrodes 3 to find an optimum value. FIG. 16 shows a flowchart of such a control operation.

First, when a density detection signal from the stirring electrode control circuit 60 is given to the optical density detection unit 70, the optical density detection unit 70 operates and emits light into the ink holding unit 5, and the intensity of the reflected light That is, the reflectance R measurement (step S
1) is performed. This reflectance R is determined by the stirring electrode control circuit 60.
Will be fed back.

The stirring electrode control circuit 60 has a reflectance threshold Rth for determining the presence or absence of colorant adhesion, and determines whether the reflectance R is greater than the threshold Rth (step S2). ). Then, the reflectance R is equal to the threshold value Rt.
If it is larger than h, it is determined that there is no adhesion of the colorant, and the process is terminated normally.

Conversely, when the reflectance R is equal to or less than the threshold value Rth,
Since it is determined that the colorant has adhered, the process enters a loop for correcting the stirring conditions. In this routine, the voltage difference dV is added to the current potential difference between the stirring electrodes 3, that is, the pulse amplitude V.
Is added. In this case, first, in step S3,
It is determined whether or not adding the increment dV to the current potential difference V does not exceed the preset threshold value Vth. In this case, the threshold voltage Vth is set to the maximum voltage that can be applied between the stirring electrodes 3. In practice, however, the breakdown voltage of the air or the insulating material between the electrodes or the maximum voltage limited by the control circuit is set. The lower voltage value will be set.

When the newly set voltage V + dV exceeds the threshold value Vth, the potential difference cannot be corrected any more, so that the process is terminated and an abnormal termination is output to the outside.

On the other hand, the newly set voltage V +
If dV is equal to or less than the threshold value Vth, in step S4, the voltage V is corrected to the voltage V + dV, and under this condition, the stirring electrode 3
Control.

While performing the stirring operation under the new condition, the density detection signal is transmitted again from the stirring electrode control circuit 60 to the optical density detection unit 70, and the adhesion state of the colorant according to the correction condition is confirmed. Thereafter, as in the previous routine, if the colorant is no longer adhered, the process ends normally. If the colorant is adhered, the routine enters a routine for correcting the stirring conditions again.

As described above, the stirring operation can be performed under the optimum stirring conditions while observing the adhesion state of the colorant, so that reliable and highly reliable stirring can be performed. Note that such feedback control can be applied to any case where the stirring operation is always performed or when it is performed as needed.

For example, when stirring is performed constantly, a pulse voltage for constantly stirring is applied to the stirring electrode 3 by the stirring electrode control circuit 60, and the optical density detection unit 70 holds the ink while constantly performing the stirring operation. The condition in the unit 5 is checked, and if ink adheres once, the stirring condition is changed to perform an operation for removing the adherence. Control such that the operation returns to the constant stirring. As a result, it is possible to always perform the stirring operation under the optimum conditions for removing the adhesion of the colorant, and highly reliable control is possible.

On the other hand, if necessary, for example,
The state inside the ink holding unit 5 is constantly checked by the optical density detecting unit 70, and when the adhesion of the coloring material is recognized, the stirring electrode control circuit 60 gives an initial voltage pulse to the stirring electrode 3 to perform the stirring operation. Then, the stirring operation is performed while searching for the optimum condition until the colorant is not adhered.

If necessary, such as at regular intervals, every fixed number of recordings, or before recording starts after a long pause, the optical density detecting unit 70 checks the status inside the ink holding unit 5 to determine the color. When the adherence of the coloring agent is recognized, the initializing voltage pulse is applied to the stirring electrode 3 by the stirring electrode control circuit 60 to perform the stirring operation, and the stirring operation is performed while searching for the optimum condition until the coloring agent is not adhered. You may do so.

There are various possible control modes based on the feedback from the optical density detection unit 70. In each case, the control conditions are changed according to the actual conditions while observing the actual adhesion of the colorant. Since the stirring operation can be performed while performing, the reliability of the stirring operation can be improved, and the state of the ink 4 can be always maintained in a good state.

When the stirring electrode 3 is made of a transparent electrode, not only is the place where the optical density detecting section 70 is installed to have a degree of freedom, but also the adhesion of the colorant to the stirring electrode 3 itself can be monitored. Further, reliability can be improved.

By the way, in the configuration of FIG.
The incident light 71a is given from the optical density detecting unit 70 to the gap between the reflected light 71b and the reflected light 71b is extracted from the same portion.
The adhesion state of the colorant at a portion corresponding to the gap between the stirring electrodes 3 was observed. For example, as shown in a partially enlarged cross-sectional view of FIG. 17, the light-emitting portion 70a and the light-receiving portion 70b were separated from each other. It may be arranged so that the path of the incident light 71a and the path of the reflected light 71b in the ink holding unit 5 are separated. In this case, the incident light 71a is given from the optical density detection unit 70 to a certain gap between the stirring electrodes 3, and the reflected light 71b is extracted from another gap between the stirring electrodes 3 and 3. , It is possible to observe the situation immediately below the stirring electrode 3.

Although the light emitting section 70a and the light receiving section 70b are shown separately in FIG. 17, it goes without saying that they may be integrated.

In this embodiment, the case where the stirring in the ink holding unit 5 is performed by the stirring electrode 3 has been mainly described. However, even when the stirring means is of a type using ultrasonic waves, the same applies. Needless to say, this is possible. However, in the case of the method using ultrasonic waves, since a member that blocks light, such as a piezoelectric body, is often used, a special device for securing the optical path of the incident light 71a and the reflected light 71b from the optical density detection unit 70 is used. Although it is necessary, at the same time as making the electrodes transparent, it is possible to take measures such as devising the shape of the piezoelectric body to secure the optical path or providing a light passage hole in the piezoelectric body. is there.

In the present embodiment, the optical density detector 70
Although the example where the color material is provided in one place is illustrated, it may be provided in a plurality of places, and the color material stirring state can be individually observed for each part, so that only the stirring means of a specific part is operated or the condition is controlled. It becomes possible. In this case, it is possible to prevent a problem caused by changing the stirring conditions, which need only be applied to a part, to all of them.

As described above, according to the present embodiment, the density detecting means by the optical method is provided adjacent to the stirring means, and the stirring means can be controlled in accordance with this. The observation result is fed back to the stirring control while observing the stirring state of the colorant in the ink holding unit, so that the state of the ink inside the ink holding unit can be always kept in a good state, and according to the state of the apparatus. There is an effect that optimal stirring control can be realized. In addition, by providing the optical density detection means at a plurality of locations, it is possible to observe the stirring state of the ink over a wide range, and it becomes possible to control the stirring under the optimal stirring conditions at each location, thus maintaining the total performance of the apparatus. effective. In addition, if transparent electrodes are used for each electrode, the applicable range of optical density detection is expanded, and the performance can be further improved. Embodiment 6 FIG. FIG. 18 is a partial plan view of the ink jet recording apparatus according to the sixth embodiment of the present invention, and is an enlarged view particularly showing the head end portion viewed from above.

As shown in the figure, a pair of density detecting electrodes 80 are provided on the ink-side surface of the upper substrate 2a, close to the stirring electrode 3. The concentration detecting electrode 80 is connected to a resistance measuring circuit 81 for measuring a resistance value between the electrodes. Then, the resistance measuring circuit 81 is connected to the stirring electrode control circuit 60.

In the configuration described above, the density detection electrode 80 has a function of detecting the colorant concentration of the ink inside the ink holding unit 5 from its resistance value, and the detection status is fed back to the stirring electrode control circuit 60. Then, the stirring operation is controlled.

The ink used in the ink holding unit 5 includes a solvent having a volume resistivity of about 10 ⁸ Ωcm and a colorant component having a volume resistivity of about 10 ¹³ Ωcm. When such an ink is used, the resistance of the ink increases when the concentration of the colorant is high, and the resistance of the ink decreases when the concentration of the colorant is low. Therefore, under the situation where the coloring agent adheres, compared to the situation where the coloring agent does not adhere,
Since the resistance value of the ink increases, it is possible to confirm the adhesion state based on the resistance value of the ink.

On the other hand, when an ink is used, to which a coloring material easily adheres when the resistance value of the ink decreases,
It is sufficient to detect that the resistance value of the ink has dropped and to stir the ink.

That is, by detecting the resistance value between the concentration detecting electrodes 80 by the resistance measuring circuit 81, it is possible to confirm the state of the stirring operation, and to feed back to the stirring control by the stirring electrode control circuit 60. it can.

How the signal from the resistance measuring circuit 81 is applied to the control by the stirring electrode control circuit 60 is exactly the same as that in the fifth embodiment, and the same effect can be obtained. is there.

It should be noted that, as in the present embodiment, the density detecting electrode 80
And a method of measuring the ink concentration by the resistance measuring circuit 81, compared with the case where light is used, requires no space and has a high degree of freedom in the installation location of the concentration detecting electrode 80.
Not only is it suitable for miniaturization of the device, it is possible to increase the degree of freedom in design. Further, in the case of using the stirring electrode 3 as the stirring means, a method in which the stirring electrode 3 and the concentration detection electrode 80 are configured by a common electrode and switched and used is also applicable. In this case, there is no need to secure a separate space for density detection, and the density detection position can be set arbitrarily, so that the degree of freedom of control can be greatly improved.

In this embodiment, the density change is detected from the change in the resistance value. However, the same effect can be expected by detecting the change in the capacitance. The device configuration in this case may be basically the same as that of FIG. 18 and can be realized by replacing the resistance measuring circuit in the figure with a capacitance measuring circuit.
Since the capacitance has a highly accurate measurement, more accurate information on the ink density can be obtained.

As described above, according to this embodiment, a pair of density detecting electrodes 80 are used as density detecting means.
Since the stirring state can be detected by the resistance value between each electrode, the ink state can be accurately detected without increasing the size of the apparatus. There is an effect that simplification is possible and a configuration very advantageous in design and manufacture can be obtained. Further, since the concentration can be detected at an arbitrary location, the controllability of stirring can be greatly improved.

Although the ink jet recording apparatus of the present invention has been described with reference to the first to sixth embodiments, each of the embodiments may be applied individually or in combination. Of course it is good.

[0133]

As described above, according to the present invention, in the ink jet recording apparatus, the ink holding section is configured to appropriately stir the ink, so that the colorant in the ink adheres to each section in the head. Can be prevented, ink management with high reliability can be performed, non-ejection and ejection failure can be prevented, and the time until ejection in the initial operation can be shortened, so that a stable recording operation can be realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged perspective view of a head end portion of the inkjet recording apparatus according to the first embodiment.

FIG. 3 is an explanatory diagram of a control operation of the recording electrode of FIG. 1;

FIG. 4 is an explanatory diagram of a control operation of the stirring electrode of FIG. 1;

FIG. 5 is a plan view illustrating a first modification of the arrangement of the stirring electrodes in the first embodiment.

FIG. 6 is a plan view illustrating a second modification of the arrangement of the stirring electrodes in the first embodiment.

FIG. 7 is a perspective view illustrating a third modification of the arrangement of the stirring electrodes in the first embodiment.

FIG. 8 is a perspective view illustrating a fourth modification of the arrangement of the stirring electrodes in the first embodiment.

FIG. 9 is a partially enlarged sectional view of an ink jet recording apparatus according to a second embodiment of the present invention.

FIG. 10 is an enlarged partial cross-sectional view illustrating a modification of the inkjet recording apparatus according to the second embodiment of the present invention.

FIG. 11 is a partially enlarged sectional view of an ink jet recording apparatus according to a third embodiment of the present invention.

FIG. 12 is a waveform chart for explaining a control operation according to the third embodiment.

FIG. 13 is a partially enlarged sectional view of an ink jet recording apparatus according to a fourth embodiment of the present invention.

FIG. 14 is a partially enlarged cross-sectional view illustrating an example of a control state according to the fourth embodiment.

FIG. 15 is a partially enlarged sectional view of an ink jet recording apparatus according to a fifth embodiment of the present invention.

FIG. 16 is a flowchart of a control method applied to the fifth embodiment.

FIG. 17 is a partially enlarged cross-sectional view for explaining a modification of the fifth embodiment.

FIG. 18 is a partial plan view of an ink jet recording apparatus according to a sixth embodiment of the present invention.

FIG. 19 is a schematic configuration diagram of a conventional inkjet recording apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 1a Recording electrode 1b Head substrate 2a Upper substrate 2b Lower substrate 2c Reinforcement material 3 Stirring electrode 4 Ink 5 Ink holding part 6 Opening 7a Ink supply path 7b Ink recovery flow path 8 Ink recirculation mechanism 9 Ink density adjustment part 10 Pump 11 Recording drum 12 Recording medium 13 Auxiliary electrode 14 Auxiliary electrode power supply 20 Sound interference layer 21 Ultrasonic generation common electrode 22 Piezoelectric body 23 Ultrasonic generation individual electrode 24 Ultrasonic generation circuit 25, 32, 42 DC power supply 30 Electrode array 31 transport driver circuit 30a-30e electrode group 40 function common electrode 40a-40e transfer electrode group 40f-40i stirring electrode group 41 function common electrode control circuit 43a ink transfer area 43b ink stirring area 43c function boundary area 50 control circuit 51 Recording power supply 60 Stirring electrode control circuit 61拌用 power 70 optical density detection portion 70a emitting portion 70b light receiving portion 71a incident light 71b reflected light 80 concentration detection electrode 81 resistance measuring circuit

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazushi Nagato 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba R & D Center (72) Inventor Yasuo Hosaka, Sachi-ku, Kawasaki-shi, Kanagawa (72) Inventor Teruo Murakami In Kochi Mukai Toshiba 1 Kawasaki-shi, Kanagawa Pref. Toshiba R & D Center

Claims (12)

[Claims] An ink holding means for holding an ink in which a colorant component is dispersed in an insulating solvent; a recording electrode for flying the colorant component in the ink held by the ink holding means by electrostatic force; And an agitating means disposed in proximity to the recording electrode to agitate the ink. 2. A stirrer comprising: a stirrer arranged at least at one position in proximity to the recording electrode; a stirrer controlling means for inverting a potential relationship between the stirrers at regular intervals; 2. The ink jet recording apparatus according to claim 1, wherein: 3. The stirring control means controls the average voltage applied to the stirring electrode to be higher than the average voltage applied to the recording electrode during ink supply, and the average voltage applied to the recording electrode during ink recovery. 3. The ink jet recording apparatus according to claim 2, wherein the control is performed so as to be lower than the voltage. 4. The apparatus according to claim 1, wherein said stirring means comprises at least one ultrasonic wave generating means for applying an ultrasonic wave to the vicinity of said recording electrode to stir said ink.
The inkjet recording apparatus according to any one of the preceding claims. 5. An ink holding means for holding an ink in which a colorant component is dispersed in an insulating solvent; a recording electrode for flying the colorant component in the ink held by the ink holding means by electrostatic force; A transport electrode for transporting the ink in the ink holding means in a supply direction and a recovery direction, and disposed at at least one location in proximity to the recording electrode;
An ink jet recording apparatus comprising: a stirring means for stirring the ink. 6. A stirrer comprising: a stirrer arranged at least at one position close to the recording electrode; and a stirrer controlling unit for inverting a potential relationship between the stirrers at regular intervals. The stirring control means controls the average voltage applied to the stirring electrode to be higher than the average voltage applied to the transport electrode during ink supply, and to be higher than the average voltage applied to the transport electrode during ink recovery. 6. The ink jet recording apparatus according to claim 5, wherein the control is performed so as to be lower. 7. An ink holding means for holding an ink in which a colorant component is dispersed in an insulating solvent; a recording electrode for flying the colorant component in the ink held by the ink holding means by electrostatic force; An ink jet recording apparatus, comprising: a common conveying and stirring unit having an area of an electrode group for conveying ink in the ink holding unit in a supply direction and a collecting direction and an area of an electrode group for stirring the ink. 8. An ink jet recording apparatus according to claim 7, wherein said common conveying and stirring means is controlled by arbitrarily switching between a conveying area and a stirring area. 9. An ink jet recording apparatus according to claim 1, wherein said stirring means is controlled based on an output of an ink density detecting means in said ink holding means. 10. The method according to claim 1, wherein the density detecting means detects the density of the ink based on an optical method.
The inkjet recording apparatus according to claim 9. 11. An ink jet recording apparatus according to claim 9, wherein said density detecting means detects the density of said ink based on the resistance of said ink. 12. An ink jet recording apparatus according to claim 11, wherein said density detecting means shares an electrode arranged in said ink holding means for detecting the resistance of said ink.