JP3286559B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an industrial ink jet recording apparatus, and more particularly, to a technique for preventing clogging of a nozzle orifice at the time of leaving the apparatus in an ink jetting stopped state and a technique for repairing clogging of a nozzle orifice of a nozzle. It is about.

[0002]

2. Description of the Related Art In a continuous type ink jet recording apparatus, as a method of preventing clogging of an ink jet port of a nozzle portion, a cleaning liquid is supplied to the nozzle portion when ink jetting is stopped, and the cleaning liquid is jetted to discharge the inside of the nozzle and the ink jet. It is known to clean the outlet and then stop the ink supply to prevent clogging. There is also known a method of preventing clogging by capping an ink jet port from drying and clogging with ink.

In addition, there has been proposed a method of forcibly flowing ink, a solvent, or a cleaning liquid to repair a nozzle when clogging occurs. In addition, the cleaning liquid is suctioned into the nozzle portion while the cleaning liquid is applied to the ink nozzle manually, thereby cleaning the ink nozzle and repairing the nozzle clogging, and removing the nozzle nozzle and cleaning with an ultrasonic cleaner or the like. A way to do that has been proposed.

[0004]

The causes of clogging of the ink ejection port can be classified into adhesion of foreign matter and adhesion of ink.
Foreign matter in the ink flow path components,
The main causes are contamination of foreign substances during production and precipitation of components in the ink.

Unless the components in the ink are deposited, the clogging of the ink jet port due to the adhesion of foreign matter can be prevented to some extent by removing foreign matter by washing components, washing the flow path after assembly, and installing a filter. Can be easily implemented, but it is difficult to completely prevent it.

On the other hand, when the ink ejection port is clogged due to the sticking of the ink, the condition is as follows.
This usually happens when the device is left unattended.
Therefore, it is necessary to remove the ink from the ink ejection port when stopping the ejection of the ink from the ink ejection state, or to prevent the ink in the ink ejection port from drying even when the ink ejection is left.

The present invention relates to the removal of ink from an ink ejection port. To remove the ink, the ink ejection port is washed with a cleaning liquid or the ink is completely sucked without using the cleaning liquid. Or either.

When a cleaning liquid is used, the liquid used for cleaning is
Ultimately, the ink flows into the ink container of the main unit, so if a large amount of cleaning liquid is used for the capacity of the ink container, it will temporarily change the physical properties of the ink, which may cause printing disturbance. is there.

In addition, using a large amount of cleaning liquid leads to an increase in running cost, and therefore, there is a problem in how to clean the ink ejection port with a very small amount of cleaning liquid.

Further, when the apparatus is left in a state where the ink ejection is stopped, the ink expands due to a change in the surrounding temperature, the ink oozes out from the nozzle portion, and the ink ejection port is clogged. However, how to prevent the bleeding of the ink is also an important problem.

When the ink ejection port is clogged, the ink is not ejected even if the inside of the nozzle is pressurized, or even if the ink is ejected, the ink ejection direction is deflected at the start of ink ejection, or the ink ejection direction is changed. In some cases, it remains bent. When these phenomena occur,
In addition to the fact that normal printing cannot be performed, it also leads to soiling of a printing object and a production line with ink.

In the case where the ink ejection port is clogged due to the adhesion of foreign matter or the ink ejection port is clogged due to the sticking of the ink, it is necessary to clean the ink ejection port, but the ink ejection port can be easily repaired in a short time. Is the problem.

[0013] An object of the present invention is to solve the above problems.
When stopping the ink ejection from the nozzle, eliminating the residual ink in the ink ejection port simply by using a small amount of cleaning liquid, and in the ink ejection stopped, even allowed to stand the device seeped ink Eliminates clogging of the ink ejection port, and even if clogging of the ink ejection port occurs,
An object of the present invention is to provide an ink jet recording apparatus capable of automatically cleaning an ink ejection port and repairing a clog in a short time.

[0014]

In order to achieve the above object, the present invention provides an ink supply channel for supplying ink, a nozzle unit for ejecting the supplied ink into ink particles, and a nozzle unit. In an ink jet recording apparatus having an ink recovery flow path for recovering excess ink from a nozzle and a cleaning liquid supply flow path for supplying a cleaning liquid to the nozzle section, the nozzle section has an orifice provided with an ink ejection port for ejecting the ink. A nozzle body having a first ink flow path for feeding the supplied ink to the ink ejection port and a second ink flow path for sucking the excess ink from the ink ejection port; and the supplied cleaning liquid. the a said feed into an ink ejection port write no cleaning liquid supply unit, and a charging electrode for charging the character signals to said ink particles, the cleaning liquid supply section, before It is linked to stop the ink ejection
Cleaning liquid tube for supplying a cleaning liquid to the nozzle portion
From the side, the cleaning liquid flow path formed in the nozzle body is added.
By pressing, the nozzle body and the charging electrode
The orifice through the cleaning solution feed channel formed by
Cleaning liquid reservoir formed by the fiss and the charged electrode
The cleaning liquid is fed into the nozzle portion , and the fed cleaning liquid is sucked into the nozzle portion from the ink ejection port.

[0015]

Another feature of the present invention is that an ink supply flow path for supplying ink, a nozzle section for ejecting the supplied ink into ink particles, and an ink for collecting excess ink from the nozzle section In an ink jet recording apparatus having a recovery flow path and a cleaning liquid supply flow path for supplying a cleaning liquid to the nozzle section, the nozzle section has an orifice provided with an ink jet port for jetting the ink, and the ink jet port has A nozzle body having a first ink flow path for feeding the supplied ink and a second ink flow path for sucking the excess ink from the ink ejection port;
Wherein a feed the supplied washing liquid to said ink ejection port write no cleaning liquid supply unit, and a charging electrode for charging the character signals to said ink particles, the cleaning liquid dispenser, the ink injection
In conjunction with stopping the discharge, the cleaning liquid is supplied to the nozzle section.
From the side of the washing liquid tube that supplies
By pressurizing the formed cleaning liquid flow path, the nozzle
Cleaning liquid formed by the body and the charged electrode
The orifice and the charging electrode
Sending the cleaning liquid into the formed cleaning liquid reservoir,
The sent cleaning liquid is configured to be sucked into the nozzle portion from the ink ejection port, and the first ink flow path and the second ink flow path are in the vicinity of the ink ejection port, and An ink reservoir is formed at a connection portion between the first ink flow path and the second ink flow path.

[0017]

Further, as another feature of the present invention , the cleaning
A liquid feed channel is formed between a front part of the nozzle body and a rear part of the charging electrode, and the cleaning liquid reservoir part is a front part of the ink ejection port, a front part of the orifice and a rear part of the charging electrode. It is formed between.

Further, as another feature of the present invention, a volatilization prevention valve is provided in the cleaning liquid flow path.

Another feature of the present invention is that the ink supply flow path and the ink recovery flow path are provided with valves for closing the respective flow paths when the apparatus is stopped.

Another feature of the present invention is that a water-repellent treatment is performed inside the orifice including the ink ejection port.

According to the present invention, the orifice of the nozzle portion is provided with an ink ejection port for ejecting ink. The nozzle body has a first ink flow path for feeding the supplied ink to the ink ejection port and a second ink flow path for sucking excess ink from the ink ejection port. The charging electrode charges the ink particles with a character signal.

[0023] Then, feed the supplied washing liquid to the ink ejection port write no cleaning liquid supply section stops the ink ejection
In conjunction with the above, the washing liquid is supplied to the nozzle portion.
The washing formed in the nozzle body from the cleaning solution tube side
By pressurizing the purified liquid flow path, the nozzle body and the front
Through the cleaning solution feed passage formed by the charging electrode.
Formed by the orifice and the charging electrode
Feeding the cleaning liquid into the cleaning liquid reservoir,
Cleaning liquid is configured to be drawn into the interior of the nozzle portion from the ink ejection port.

Accordingly, when the ink remaining in the ink ejection port when the ink ejection is stopped causes clogging after leaving the apparatus, and when the ink ejection port is clogged due to adhesion of foreign matter or the like, the ink is washed with a minute cleaning liquid. The spout can be cleaned.

The volume of the cleaning liquid to be cleaned can be reduced to about one hundredth of the ink volume in the apparatus.
There is no problem with changes in the physical properties of the ink.

In addition, an ink reservoir is formed near the ink ejection port at a connection between the first ink flow path and the second ink flow path.

With this arrangement, when the ink ejection is stopped, the ink in the nozzles is sucked, and the apparatus is left unattended, the residual ink at the time of ink suction and the residual ink mixed with the residual ink due to a change in the surrounding temperature are caused. Even if the combined air expands, the ink remaining portion can block the remaining ink for the expanded portion, thereby preventing the residual ink from oozing out from the ink ejection port and sticking.

Further, by combining the cleaning of the ink jet port by feeding a minute cleaning liquid and suctioning the cleaning liquid into the nozzle, and preventing the ink from bleeding out of the residual ink by the ink reservoir inside the nozzle, the fixing of the ink jet port by the residual ink is achieved. Can be prevented, and the reliability against clogging can be improved.

By providing a washing liquid reservoir between the front of the orifice and the rear of the charging electrode at the front of the ink ejection port, the washing liquid to be sent is stored in the washing liquid reservoir, and the sent washing liquid is ejected by the ink jet. It can be held in the washing liquid reservoir until sucked from the outlet. Thus, it is possible to prevent the cleaning liquid from flowing out to another part.

Further, the washing solution flow path, formed in the nozzle body, the washing liquid feed passage, by forming between the rear of the front and the charging electrodes of the nozzle body, by feeding a cleaning liquid to structurally ink ejection port And the number of structural parts can be reduced.

Further, by providing the volatilization prevention valve to the washing solution flow path, prevents volatilization of the cleaning liquid feeding, the discharge flow rate of the cleaning liquid can be stabilized.

Further, by providing a valve for closing the respective flow paths when the apparatus is stopped in the ink supply flow path and the ink recovery flow path, it is possible to prevent the ink or the cleaning liquid from flowing out to the nozzle portion due to the expansion of the ambient temperature. And assists the action of blocking residual ink.

Further, by performing a water-repellent treatment inside the orifice including the ink ejection port, the cleaning property of the ink ejection port can be improved. Further, when sucking ink from the ink ejection port, the residual ink at the ink ejection port can be eliminated without using a cleaning liquid.

[0034]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink jet recording apparatus according to an embodiment of the present invention will be described with reference to the drawings. In addition,
1 to 9 have the same reference numerals.

First, referring to FIGS. 1 and 2, a description will be given of a nozzle portion, a component arrangement near the nozzle portion, and a basic operation of the nozzle portion of an ink jet recording apparatus according to an embodiment of the present invention. FIG. 1 shows a longitudinal section of the nozzle portion, and FIG. 2 shows the arrangement of the nozzle portion and the tubes provided in the nozzle portion, and the valves near the nozzle portion, that is, the supply valve and the recovery valve.

As shown in FIG. 1, the nozzle unit 1 includes a nozzle body 2 and a charging electrode 14 fixed to the nozzle body 2.
And an orifice 4 fitted in the nozzle body 2 and a cylindrical electrostrictive element 3 provided in the nozzle body 2. The nozzle body 2 has a first ink flow path 5a, a second ink flow path 5b, and an ink reservoir 5c.

An O-ring 6 seals between the nozzle body 2 and the electrostrictive element 3 which are close to the ink reservoir 5c. The electrostrictive element 3 is fixed by an electrostrictive element holding screw 9 via an electrostrictive element holder 8.

The both surfaces of the electrostrictive element 3 are a (+) electrode 3a and a G electrode 3b. The (+) electrode 3a on the electrostrictive element holder 8 side is connected to a (+) terminal 11 through an electrode spring 10. Is done. By connecting the (+) terminal 11 to the (+) electric wire 12a, current is supplied from the (+) electric wire 12a to the (+) electrode surface 3a of the electrostrictive element 3.

The G electrode 3b of the electrostrictive element 3 is connected to the G terminal 13 through the electrostrictive element retainer 8 plated with the outer periphery.
By connecting the G terminal 13 to the G electric wire 12b, current is supplied from the G electric wire 12b to the G electrode surface 3b of the electrostrictive element 3.

The space between the nozzle body 2 and the orifice 4 which is close to the ink reservoir 5c is sealed by an O-ring 7. The orifice 4 connects the charging electrode 14 with a screw 15
And is fixed by tightening to the nozzle body 2.

On the other hand, a cleaning liquid flow path 16 is also formed in the nozzle body 2, and an O-ring 17, a ball 18,
The spring 19 is sealed except when the cleaning liquid is fed . Further, the washing liquid feed passage 20 is formed by the charging electrode 14 and the nozzle body 2. In addition, feeding cleaning solution
A cleaning liquid reservoir 21 is formed at the tip of the insertion channel 20 by the charging electrode 14 and the orifice 4.

When printing is performed, the first ink flow path 5a
And pressurized ink to eject the ink from the ink ejection port 4a. The ink particles 22 are created by vibrating the pressurized first ink flow path 5 a at a constant frequency by the electrostrictive element 3.

When the ink jetting from the ink jetting port 4a is stopped, the pressures in the first ink flow path 5a and the second ink flow path 5b are set to a negative pressure.
The air outside the nozzle portion 1 is sucked more. Also, in conjunction to stop the ink ejection, by pressurizing the washing solution flow path 16 from the cleaning liquid tube 27 side, the cleaning liquid feed
The cleaning liquid is fed into the cleaning liquid reservoir 21 through the flow channel 20.

At this time, since the first ink flow path 5a, the second ink flow path 5b, and the ink reservoir 5c have a negative pressure, the cleaning liquid accumulated in the cleaning liquid reservoir 21 is discharged from the ink jet port 4a. The ink ejection port 4a is cleaned by sucking the ink into the first ink flow path 5a and the second ink flow path 5b via the ink reservoir 5c.

Although the cleaning liquid used here is a general ink cleaning liquid, a solvent for controlling the physical properties of the ink may be used.

FIG. 2 is a diagram showing the arrangement of the nozzle portion, the tube provided in the nozzle portion, and the valve in the vicinity of the nozzle portion. As shown in FIG. 2, the ink supply flow path to the nozzle unit 1 is arranged in the order of the supply tube 23a, the supply valve 24, and the supply tube 23b to the nozzle unit 1. In addition, nozzle part 1
The ink recovery flow path is disposed in the order of the nozzle section 1, the recovery tube 25b, the recovery valve 26, and the recovery tube 25a.

When the pressurized ink is supplied to the nozzle section 1, the supply tube 23 is opened with the supply valve 24 opened.
The pressurized ink is supplied to a. The supplied ink flows to the nozzle unit 1 through the supply valve 24 and the supply tube 23b. Conversely, the first ink flow path 5 inside the nozzle portion 1
(a) When a negative pressure is applied to the second ink flow path 5b and the ink reservoir 5c, ink is sucked from the collection tube 25b.

Next, the characteristics of the ink jet recording apparatus according to the present invention and matters to be improved by one embodiment of the present invention will be described with reference to FIGS.

In order to prevent or repair the clogging of the ink ejection port 4a, it is effective to wash the ink ejection port 4a with a cleaning liquid. However, if a large amount of the cleaning liquid is used, the physical properties of the ink are changed. . FIG. 3 shows a change in ink viscosity with respect to a cleaning liquid addition rate of a certain ink at room temperature.

Various physical properties of the ink are changed by adding the cleaning liquid. Among them, as shown in FIG.
The change in ink viscosity is remarkable, and particularly causes a large change in the flow rate and ejection speed from the ink ejection port 4a. In order to perform stable printing, the change in ink viscosity must be reduced.

As a method of cleaning the ink ejection port 4a,
There is a method in which the cleaning liquid is ejected from the inside of the nozzle portion 1 to wash the entire ink flow path and the ink reservoir 5c inside the nozzle portion 1.

However, in the case of the continuous ink jet recording apparatus, of the liquid ejected from the ink jetting port, those not used for printing are collected and returned to an ink container (not shown) in the apparatus and reused. However, when the ink ejection port is cleaned from the inside, the liquid used for cleaning also enters the ink container without exception, and causes a change in ink viscosity.

For this reason, it is necessary to minimize the amount of the cleaning liquid used for cleaning. However, when the cleaning liquid is supplied from the supply tube 23a, the inner diameter of the supply tube 23a becomes φ
1. When the length is 2 m, a solvent of about 12,000 mm ³ is required, and even if the cleaning liquid is directly introduced into the nozzle portion 1, a cleaning liquid of at least 3,000 mm ³ is required.

Normally, the circulation system of an ink jet recording apparatus has a function of keeping the ink viscosity or ink concentration constant. However, when the ink is temporarily diluted as described above, it takes a long time to return to the original state. Takes a long time, which may cause printing disorder.

When these washing operations are repeated, the ink is further diluted. Therefore, it is necessary to prevent the washing operation from being repeated or to provide a function for forcibly evaporating the washing liquid. In addition, using a large amount of the cleaning liquid is not desirable both in terms of cost and environment.

On the other hand, in the method of cleaning the ink jet port 4a by suctioning the cleaning liquid from the ink jet port 4a into the ink reservoir 5c and each ink flow path, it is sufficient if the amount of the cleaning liquid required for cleaning is 100 mm ^3. is there.

Since the amount of the cleaning liquid is very small with respect to the amount of ink in the circulation system of 300,000 to 600,000 mm ³ , the effect on the physical properties of the ink is at a level that does not cause any problem.

In addition, if the cleaning operation of cleaning the ink ejection port 4a by sucking the cleaning liquid from the ink ejection port 4a into each ink flow path and the ink reservoir 5c is performed manually, the dispersion of the operation and the time required for the operation are increased. Although there is a problem, it is possible to automate the cleaning operation by providing a flow path for discharging the cleaning liquid in the vicinity of the ink jetting port 4a and sending the cleaning liquid toward the ink jetting port 4a and simultaneously suctioning the cleaning liquid into the nozzle 1. It is possible to improve the work reliability and shorten the work time.

Apart from the above problem, even when the ink is not ejected, that is, when the ink is not attached to the ink ejection port 4a when the apparatus is stopped, if the apparatus is left unattended, the residual ink in the nozzle portion 1 is removed. In some cases, ink oozes from the ink ejection port 4a and the ink adheres to the vicinity of the ink ejection port 4a.

When the ink sticks, not only cannot the normal printing be performed, but also if the ink cannot be ejected or the ink is ejected because the ink is stuck to the ink ejection port 4a even if the ink is ejected. Also, since the flight direction of the ink immediately after the ejection deviates from the normal position, the other parts and the printing object are stained.

In order to prevent such a phenomenon, it is necessary to prevent the ink from adhering to the ink ejection port 4a and its vicinity even when the apparatus is left in a state where the ejection of the ink is stopped.

The cause of this phenomenon is mainly due to the expansion of the ink volume due to a temperature change. Tube diameter is inner diameter φ
2. FIG. 4 shows the relationship between the temperature rise and the volume of the expanded ink when the tube length is 4 m.

As shown in FIG. 4, the ink volume expands due to the temperature rise. Similarly to this phenomenon, if the ambient temperature rises when the apparatus is stopped, the expanded volume of ink in the tube connected to the nozzle unit 1 tends to bleed from the ink ejection port 4a.

A method for preventing the ink from sticking to the ink ejection port 4a even when the apparatus is left in a state where the ejection of the ink is stopped is to prevent the ink of the expansion amount from flowing toward the ink ejection port 4a. Alternatively, even if the ink flows, the ink is prevented from oozing from the ink ejection port 4a.

According to the embodiment of the present invention, only the air in each ink flow path and the ink reservoir 5c in a state where the ink and the air are mixed are discharged from the ink ejection port 4a. Therefore, it is possible to prevent ink seepage from the ink ejection port 4a and to prevent the ink ejection port 4a from being stained with ink. Specific contents will be described below with reference to FIGS.

FIGS. 5 to 7 are simplified cross-sectional views of the nozzle section 1 shown in FIG. 1, and show the state of the ink when the apparatus is left after the ejection of the ink is stopped. Normally, the nozzle unit 1 of the ink jet recording apparatus can be directed in all directions, such as upward, downward, and sideways, depending on the printing direction.

FIG. 5 is a view showing a state where the nozzle unit 1 is mounted downward, FIG. 6 is a state after installation, and FIG.

As shown in FIG. 5, when the nozzle portion 1 is mounted downward, the residual ink inside the nozzle portion 1 and the expanded ink pushed out due to the temperature change are supplied to the ink reservoir 5c on the outer periphery of the orifice 4. Can be stored as residual ink 28.

As a result, the ink does not flow into the inner periphery of the orifice 4, and only the air is discharged from the ink ejection port 4a, so that the bleeding of the ink can be prevented.

When the nozzle portion 1 is mounted upward as shown in FIG. 6, and when the nozzle portion 1 is mounted horizontally as shown in FIG. 7, the residual ink 28 similarly oozes out from the ink ejection port 4a. Not to be.

In the present invention, the cleaning liquid is supplied to the nozzle portion 1 and the ink flow path inside the nozzle portion 1 and the ink reservoir 5c are washed with the cleaning liquid, so that the cleaning liquid does not flow out to the ink ejection port 4a. Therefore, it is possible to prevent the dissolved matter in the cleaning liquid from sticking to the ink ejection port 4a.

Further, as described above, the minute cleaning solution is supplied.
By cleaning the ink jet port by suctioning the cleaning liquid into the nozzle unit 1 and preventing the bleeding of the residual ink 28 by the ink reservoir 5c inside the nozzle unit 1,
It is possible to prevent the ink ejection port 4a from being fixed by the residual ink, and to improve the reliability against clogging.

Further, in this embodiment, as shown in FIG. 2, a supply valve 24 and a recovery valve 26 which are closed when the apparatus is stopped are provided in a tube near the nozzle portion 1. Even if the volume of the ink or the cleaning liquid in the tube on the main body circulating system side expands due to a temperature rise or the like for each valve, closing each valve can prevent the ink or the cleaning liquid from flowing out to the nozzle portion 1. . That is, the outflow of the ink or the cleaning liquid into the inside of the nozzle unit 1 is minimized.

According to the above-described method, it is possible to automatically prevent clogging of the ink ejection port 4a and repair the clogging. It is necessary to stabilize the discharge of the used cleaning liquid.

Hereinafter, the improvement of the cleaning performance and the stabilization of the discharge of the cleaning liquid in one embodiment of the present invention will be described. First, the improvement of the cleaning property will be described.

If the cleaning performance of the inner periphery of the orifice 4 is poor, there is a possibility that the ink drips to the ink ejection port 4a by its own weight depending on the installation direction of the nozzle portion 1. In order to improve the cleaning performance, it is one method to repeat the cleaning operation several times. However, by performing a water-repellent treatment on the inner circumference or the entire circumference of the orifice 4 according to an embodiment of the present invention, The cleaning property is improved, and the residual ink hardly remains on the inner periphery of the orifice 4 after the cleaning, and the clogging of the ink ejection port can be prevented.

Depending on the timing of the suction operation into the nozzle portion 1, the inner periphery or the entire periphery of the orifice 4 is subjected to a water-repellent treatment so that the orifice 4 can be used without using a cleaning liquid.
The ink remaining on the inner periphery of the orifice 4 can be eliminated only by sucking the ink.

Next, the stabilization of the discharge of the cleaning liquid will be described. To stabilize the discharge of the cleaning liquid used for cleaning, it is necessary that most of the discharged cleaning liquid can be sucked into the nozzle portion 1 from the ink ejection port 4a and that the discharge amount of the cleaning liquid is always stable.

As shown in FIG. 8, a (+) deflecting electrode 29a for deflecting the ink particles ejected from the nozzle 1 is provided near the nozzle 1 of the ink jet recording apparatus.
(-) A deflection electrode 29b and a gutter 30 for collecting ink particles not used for printing are arranged.

If the cleaning liquid for cleaning the ink jet port 4a adheres to these parts, the (+) deflecting electrode 29a and the (-) deflecting electrode 29b are used until the cleaning liquid is dried or the cleaning liquid is wiped off. Alternatively, there is a high possibility that high voltage leakage occurs between the gutters 30.

When a high voltage leak occurs, not only an electric field for deflecting the ink particles cannot be generated, but also a noise source of a sensor near the nozzle unit 1, so that normal printing cannot be performed. Therefore, printing cannot be performed immediately after cleaning the vicinity of the ink ejection port 4a.

In one embodiment of the present invention, the nozzle outlet 4a
When performing the cleaning, as shown in FIG. 1, since the tip of the cleaning solution infeed <br/> channels 20 cleaning liquid reservoir portion 21 is formed by the orifice 4 and the charging electrode 21, feeding cleaning solution
The cleaning liquid discharged from the inflow channel 20 is once stored in the cleaning liquid reservoir 21 and then sucked into the ink reservoir 5b through the ink ejection port 4a.

Therefore, when the discharged cleaning liquid is within a certain amount, most of the discharged cleaning liquid is sucked from the ink ejection port 4a, so that the cleaning liquid flows to other parts and adheres to parts such as deflection electrodes. There is no.

The discharge amount of the cleaning liquid is basically controlled by the time during which pressure is applied to the cleaning liquid flow path 16. However, the flow rate can also be changed by changing the inner diameter and length of the cleaning liquid tube 27 and the magnitude of the applied pressure. Therefore, the time is set by finding a controllable area.

The outlet of the cleaning liquid flow path 16 in FIG.
A valve for preventing volatilization is constituted by the ring 17, the ball 18, and the spring 19, thereby preventing the cleaning liquid from volatilizing over time. In FIG. 9, when these valve parts are not provided,
The relationship between the elapsed time and the volatilization amount of the cleaning liquid at 45 ° C. is shown.

Here, the case where the cleaning liquid is methyl ethyl ketone as an organic solvent is shown. However, as shown in FIG. 9, if there is no valve for preventing volatilization, the cleaning liquid volatilizes, and a certain amount of cleaning liquid is ejected. It will be difficult.

With the above-described method, the discharge of the cleaning liquid can be stabilized, and the reliability against clogging can be improved.

[0088]

According to the present invention, the cleaning liquid is sucked into the nozzle portion from outside the ink discharging port to clean the ink discharging port, so that the cleaning liquid consumed when cleaning the ink discharging port when the apparatus is stopped. The amount is small.

Further, even when the ink jetting port is clogged, the ink jetting port can be automatically cleaned, so that the ink jetting port can be repaired in a short time.

Further, even if the apparatus is left in a stopped state, the ink is prevented from sticking to the ink ejection port, so that maintenance when ejecting the ink after leaving the apparatus can be eliminated. .

Since only a small amount of cleaning liquid is required for cleaning, there is almost no effect on the physical properties of the ink, and the cleaning liquid used for cleaning does not adversely affect the print quality.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a nozzle portion of an ink jet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a layout diagram of components in the vicinity of a nozzle unit in FIG. 1;

FIG. 3 is a diagram illustrating a relationship between a cleaning liquid addition rate and ink viscosity characteristics.

FIG. 4 is a diagram illustrating a relationship between a rising temperature and an expanded volume of ink.

FIG. 5 is a diagram illustrating a state of ink accumulation in the nozzle portion when the nozzle portion in FIG. 1 is left facing downward.

FIG. 6 is a diagram showing a state of ink accumulation in the nozzle portion when the nozzle portion in FIG. 1 is left standing with the nozzle portion facing upward.

7 is a diagram showing a state of ink accumulation in the nozzle portion when the nozzle portion in FIG. 1 is left sideways.

8 is a diagram showing a component arrangement in the vicinity of an ink ejection side of a nozzle unit in FIG. 1;

FIG. 9 shows a case where a volatilization prevention valve is not provided in the cleaning liquid flow path of FIG.
It is a figure which shows the volatilization amount of the washing | cleaning liquid in 45 degreeC with elapsed time.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Nozzle part, 2 ... Nozzle body, 3 ... Electrostrictive element, 4 ...
Orifice, 4a: ink ejection port, 5a: first ink flow path, 5b: second ink flow path, 5c: ink reservoir,
6, 7: O-ring, 8: Electrostrictive element holding screw, 9: Electrostrictive element holding screw, 10: Electrode spring, 11: (+) terminal, 12a ...
(+) Electric wire, 12b: G electric wire, 13: G terminal, 14: charging electrode, 15: screw, 16: cleaning liquid flow path, 17: O-ring, 18: ball, 19: spring, 20: cleaning liquid feeding <br / > Flow path, 21: Cleaning liquid reservoir, 22: Ink particles, 23
a, 23b: supply tube, 24: supply valve, 25a, 2
5b: collection tube, 26: collection valve, 27: cleaning liquid tube, 28: residual ink, 29a: (+) deflection electrode, 2
9b ... (-) deflection electrode, 30 ... gutter

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomiyoshi Sato 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Within the Electric Appliances Division, Hitachi, Ltd. (72) Inventor Seiji Fujikura 1-chome, Higashitaga-cho, Hitachi City, Ibaraki Prefecture No. 1-1 Hitachi, Ltd.Electrical Equipment Division (72) Inventor Tetsunori Kaneko 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside, Hitachi, Ltd.Electrical Equipment Division (56) References 7-314703 (JP, A) JP-A-61-98545 (JP, A) JP-A-2-54536 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B41J 2/165 B41J 2/175 B41J 2/18 B41J 2/185

Claims (3)

(57) [Claims] An ink supply passage for supplying ink; a nozzle for ejecting the supplied ink as ink particles; an ink recovery passage for collecting excess ink from the nozzle; An ink jet recording apparatus having a cleaning liquid supply flow path for supplying a cleaning liquid to the ink jet recording apparatus, wherein the nozzle portion has an orifice provided with an ink jetting port for jetting the ink, and a first for feeding the supplied ink to the ink jetting port. and the nozzle body forming a second ink flow path for sucking said excess ink from the ink passage and the ink ejection port of said feed the supplied washing liquid to said ink ejection port write no cleaning liquid supply unit, the ink A charging electrode for charging a character signal to the particles, wherein the cleaning liquid supply unit stops the ejection of the ink.
The cleaning liquid supply nozzle supplies the cleaning liquid to the nozzle portion in conjunction with the cleaning liquid.
Cleaning liquid flow formed in the nozzle body from the tube side
By pressurizing the path, the nozzle body and the charging
Through the cleaning solution feed channel formed by the electrodes
Cleaning liquid formed by the orifice and the charged electrode
An ink jet recording apparatus , wherein the cleaning liquid is fed into a reservoir, and the fed cleaning liquid is sucked into the nozzle portion from the ink ejection port. 2. An ink supply channel for supplying ink, a nozzle for ejecting the supplied ink as ink particles, an ink recovery channel for collecting excess ink from the nozzle, and the nozzle. An ink jet recording apparatus having a cleaning liquid supply flow path for supplying a cleaning liquid to the nozzle, wherein the nozzle portion has an orifice provided with an ink jetting port for jetting the ink, and a first for feeding the supplied ink to the ink jetting port. A nozzle body formed with a second ink flow path for sucking the excess ink from the ink flow path and the ink ejection port, a cleaning liquid supply unit for feeding the supplied cleaning liquid to the ink ejection port, and A charging electrode for charging a character signal, wherein the cleaning liquid supply unit interlocks with stopping the ejection of the ink; The cleaning liquid flow path formed in the nozzle body is pressurized from the cleaning liquid tube side for supplying the cleaning liquid to the cleaning liquid passage formed in the nozzle body, and formed by the orifice and the charging electrode through the cleaning liquid feeding flow path formed by the nozzle body and the charging electrode. The cleaning liquid is supplied into the cleaning liquid reservoir, and the supplied cleaning liquid is sucked into the nozzle portion from the ink ejection port. The first ink flow path and the second ink flow path An ink jet recording apparatus is characterized in that an ink reservoir is formed in the vicinity of the ink ejection port and at the connection between the first ink flow path and the second ink flow path. 3. The cleaning liquid supply channel according to claim 1, wherein the cleaning liquid supply flow path is formed between a front part of the nozzle body and a rear part of the charging electrode.
An ink jet recording apparatus formed between a front portion of the orifice and a rear portion of the charging electrode on a front surface of the ink ejection port.