JP2000203051A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To well perform accurate printing over a long period of time by preventing the lowering of the concn. of the ink stored in an ink tank accompanied by the reflux of the solvent used in the washing of ink supply and recovery systems including jet nozzles. SOLUTION: In a main body case 1 equipped with an ink tank T1, a supply ink tank T2 and a solvent tank T3, a reservoir tank T4 constituted separately from these tanks is provided and the solvent used in the washing of the jet nozzles 20 in a recording head 2 to be mixed with ink and returned into the main body case 1 through a solvent recovering tube 33, a gutter 21 and an ink recovering tube 32 is introduced into the reservoir tank T4 by changing over a solenoid changeover valve K1 to be stored therein.

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 for ejecting ink from an ejection nozzle to form a pattern on an object, and more particularly, to deflect granular ink continuously ejected from the ejection nozzle only when necessary. The present invention also relates to a continuous-type ink jet recording apparatus that forms a desired pattern in accordance with the amount of deflection.

[0002]

2. Description of the Related Art Continuous ink jet recording apparatuses have been widely used as convenient recording apparatuses for forming various patterns such as characters and figures on various industrial products.

FIG. 2 is a schematic diagram showing a schematic configuration of a continuous type ink jet recording apparatus. As shown in the figure, the ink jet recording apparatus is configured by connecting a main body case 1 and a recording head 2 with a connecting tube 3. The main body case 1, an ink tank T ₁ and replenisher tank T ₂ where ink for printing is stored, and a solvent tank T ₃ the solvent of the ink is stored, a hollow casing provided therein.

A supply pipe 10 for supplying ink or a solvent and supplying ink or a solvent collected from the recording head 2 as will be described later, and an ink for supplying the recording head 2 to the ink tank T _1. Supply pipe 11 and an exhaust pipe 12 communicating with the outside air. The middle of the feed pipe 10 are a pump P ₁ for feeding is interposed, delivery of ink or solvent in the ink tank T ₁ is no as done by the operation of the pump P ₁ is there. In the middle of the supply pipe 11, an ink supply pump P ₂ , a filter F ₁ and a regulator R are interposed, and the ink stored in the ink tank T ₁ is sent out by the operation of the pump P _2. is, the foreign matter is removed by filter F _1, also to adjust the pressure by the regulator R, as will be described later, it is no to be supplied to the recording head 2 through the internal connection tube 3.

[0005] replenishing the ink tank T ₂ are, replenishment pipe 13 for delivering the ink for replenishing the ink tank T ₁ is connected. The replenishing pipe 13 is connected to the feed pipe 10 via the electromagnetic on-off valve V _1, replenisher tank T ₂
Ink for replenishment stored within the by the operation of the pump P ₁ when the electromagnetic on-off valve V ₁ is being opened, without to be supplied into the ink tank T ₁ through the replenishment pipe 13 and delivery tube 10 It is. Incidentally, this supply, when the ink in the ink tank T ₁ is decreased by the operation described below, to compensate for the decrease is performed to properly maintain the ink remaining amount in the ink tank T _1.

[0006] The solvent tank T ₃ is connected to a feed pipe 14 for feeding the solvent stored therein. The feed tube 14, solenoid valve are arranged in parallel in the electromagnetic on-off valve V ₁ V
_The solvent stored in the solvent tank T ₃ is connected to the feed pipe 10 via the feed pipe 14 and the feed pipe 14 by the operation of the pump P ₁ when the solenoid on-off valve V ₂ is opened. Supply pipe 10
The are no to be supplied into the ink tank T ₁ through. Incidentally, this supply, when the solvent component contained in the ink in the ink tank T ₁ is lost by evaporation, to compensate the loss amount is performed to properly maintain the concentration of the ink.

A pump P ₃ and a filter F ₂ for supplying a solvent are interposed in the middle of the feed pipe 14.
Is connected to the branch pipe 14a on the upstream side of the solenoid valve V _2, the solvent in the solvent tank T ₃ is sent by the operation of the pump P _3, it is removed of dust by the filter F _2, the branch It is introduced into the tube 14a, and is supplied directly to the recording head 2 via the inside of the connecting tube 3 as described later. This supply is performed to clean the ejection nozzles 20 built in the recording head 2 as described later, including the ink supply system and the recovery system. This cleaning, in particular,
This is performed when the operation of the inkjet recording apparatus is stopped.

The feed pipe 10 has an electromagnetic on-off valve V ₁ ,
Solvent recovery pipe 16 via solenoid on-off valve V ₃ installed in parallel with V ₂
Are connected, and these solenoid on-off valves V ₁ , V ₂ , V
_An ink recovery pipe 15 is connected to the downstream side of ₃ . Solvent recovery pipe 16, is provided with in order to recover the used for cleaning the recording head 2 inside the injection nozzle 20 solvent, the solvent is recovered in the solvent recovery pipe 16, when the solenoid valve V ₃ is opened the operation of the pump P _1, an ink tank T through the feed pipe 10
_It is made to be returned within ₁ . The ink collection tube 15
In the operation of the recording head 2 to be described later, the ejection nozzle
Yes is injected from 20 provided so as to collect the excess ink that has not been subjected to printing, excess ink is recovered into the ink recovery tube 15, the ink tank T ₁ through the feed pipe 10 by the operation of the pump P ₁ It is made to be returned inside.

On the other hand, inside the recording head 2, an ejection nozzle 20 for ejecting the supplied ink in one direction as described later,
A collecting gutter 21 arranged to face the jet flow from the jet nozzle 20, a charging electrode 22 and a deflecting electrode 23 juxtaposed along the jet path from the jet nozzle 20 to the gutter 21.
And are provided.

FIG. 3 is a schematic diagram showing a schematic configuration of the injection nozzle. The ejection nozzle 20 includes a hollow main body block 2a into which ink or a solvent is supplied, and a piezoelectric vibrator 2b mounted on one side of the main body block 2a with its vibrating piece protruding inward. It becomes. The main body block 2a has a small-diameter nozzle hole 2c penetrating the inside and outside of the end wall opposite to the mounting side of the piezoelectric vibrator 2b, and a supply port penetrating the inside and outside of the peripheral wall on the same side as the mounting side of the piezoelectric vibrator 2b. 2d, and a discharge port 2e that penetrates the opposite peripheral wall in and out.
Inside the main body block 2a, there is provided a nozzle portion whose diameter is reduced toward a position where the nozzle hole 2c is formed, and the piezo vibrator 2b has a tip of the vibrating piece facing the vicinity of the nozzle hole 2c. It is arranged.

In the injection nozzle 20 configured as described above, when ink maintained at a predetermined pressure through the supply port 2d is introduced into the inside of the main body block 2a, the ink flows through the small-diameter nozzle hole 2c. It is injected at a predetermined speed.
At this time, when a predetermined voltage is applied to the piezo vibrator 2b to vibrate, the jet of ink ejected through the nozzle hole 2c has a waveform constricted as shown in FIG. The constriction gradually becomes deeper as it moves in the ejection direction, separates from each other due to surface tension, and flies as spherical ink particles I ₁ , I ₂ , I ₃ . At this time, the discharge port 2e is closed.

The charging electrode 22 is provided with the ink particles I as described above.
_1, I _2, is disposed at a position where separation occurs in the I ₃ ... to, also the deflection electrodes 23, Yes be disposed immediately after the position where the separation occurs, the ink particle I _1, I _2, I ₃ … is a charged electrode
When passing through the disposition position of the deflecting electrode 23, the deflecting electrode 23 is individually charged to a different potential according to the voltage applied thereto.
Pass the installation position of. A high DC voltage is applied to the deflecting electrode 23, and an electric field of a predetermined intensity is formed at a position where the deflecting electrode 23 is disposed, and ink particles I ₁ , I ₂ , and I ₂ passing through this position are disposed. I ₃ ... Are deflected by the action of the electric field in accordance with the respective amounts of charge, jump out of the recording head 2, collide with an object (not shown), and apply characters, graphics, etc. to the surface of the object. A desired pattern is formed. on the other hand,
The ink particles that are not charged when passing through the charging electrode 22 travel straight without being deflected at the position where the deflection electrode 23 is provided, and are caught by the collecting gutter 21.

The connecting tube 3 connecting the recording head 2 and the main body case 1 as described above is a hollow tube made of a flexible material, and includes an ink supply tube 30, a solvent supply tube 31, an ink recovery tube 32, and A solvent recovery tube 33 is included. Each of the tubes 30, 31, 32, and 33 is extended inside the main body case 1. The extended end of the ink supply tube 30 is connected to the ink supply tube 11, and the extended end of the solvent supply tube 31 is connected to the supply of the solvent. The extension end of the ink collection tube 32 is connected to the branch tube 14a branched from the tube 14, the ink collection tube 15 is extended, and the extension end of the solvent collection tube 33 is connected to the solvent collection tube.
16 are connected to each other.

Each of the tubes 30, 31, 32, and 33 is also extended inside the recording head 2. The extended ends of the ink supply tube 30 and the solvent supply tube 31 are connected to separate electromagnetic switching valves K. _1, via the K ₂ are connected to the supply port 2d provided in the injection nozzle 20, also ink recovery tube
The extended end of 32 is connected to a collecting gutter 21 disposed directly opposite the injection nozzle 20, and the extended end of the solvent recovery tube 33 is connected to the discharge port 2e provided in the injection nozzle 20. I have.

The ink is supplied to the recording head 2 by opening the solenoid valve K ₁ and connecting the supply port 2 d to the ink supply tube 30. From the charging electrode 22 and the deflection electrode
By the above-described operation of 23, it is sent from the recording head 2 and used for pattern formation. In such ink jet, but discharge port 2e provided in the injection nozzle 20 is closed, the closure is realized by the electromagnetic on-off valve V ₃ of the main body case 1 closed.

A part of the ink which is not charged when passing through the charging electrode 22 and goes straight without being charged and is caught by the gutter 21 is sucked by the operation of the pump P ₁ and the ink collecting tube 32.
And it is collected in an ink tank T ₁ through the feed pipe 10. The said pump P ₁ this time, the air is sucked along with the captured ink gutter 21, this air is also introduced into the ink tank T _1, the air, opens into the ink tank T ₁ The air is discharged to the outside air through the exhaust pipe 12.

Meanwhile, the supply port 2d and opening the solenoid valve K ₂ connected to the solvent supply tube 31, the body case 1
When the internal pump P ₃ is driven, the solvent stored in the solvent tank T ₃ is supplied to the ejection nozzle 20 inside the recording head 2 via the supply pipe 14, the branch pipe 14a and the solvent supply tube 31. Such a supply of the solvent is performed, for example, to wash the ejection nozzle 20 in a state where the ejection of the ink is stopped with the solvent including the ink supply system and the recovery system during the suspension of the operation of the inkjet recording apparatus. And
This cleaning is indispensable to prevent clogging of the ejection nozzle 20 due to solidification of the ink and the ink supply system and the recovery system.

At this time, the solenoid on-off valve V inside the main body case 1
_When the print head ₃ is opened, most of the solvent supplied to the recording head 2 flows back into the main body case 1 through the solvent recovery tube 33, and flows through the solvent recovery tube 16 and the supply tube 10 to the ink tank T _1. And a part of the solvent is ejected from the ejection nozzle 20 and captured by the gutter 21, returned to the main body case 1 via the ink recovery pipe 15, and returned to the ink tank T ₁ via the supply pipe 10. Will be returned.

[0019]

However, in the conventional ink jet recording apparatus configured as described above,
The solvent used for cleaning the injection nozzle 20 is the ink tank T
From being returned to _1, and decreases the concentration of the ink stored in the ink tank T ₁ gradually, there is a problem that the viscosity of the ink can not be maintained properly.

When the ink having the reduced viscosity is supplied to the recording head 2, the ink granulation after being ejected from the ejection nozzle 20 as described above is hindered, and the size of the ink particle becomes defective or granulated. Incorrect printing may occur due to misalignment or the like, and accurate printing may not be possible. May be extremely reduced and printing itself may not be possible. The concentration of the ink in the ink tank T ₁ is as described above, has been adjusted by the supply of the solvent from solvent tank T _3, this adjustment is made for to compensate the increase in concentration due to evaporation of the solvent However, it is impossible to prevent the concentration from decreasing.

[0021] On the other hand, in the conventional ink jet recording apparatus, air that returns to the ink tank T ₁ with captured ink gutter 21, so as to be exhausted through an exhaust pipe 12 communicating with the ink tank T ₁ However, this air contains a large amount of vaporized solvent components, and this vaporized solvent is released to the outside air together with the exhaust gas and is lost, so the consumption of the solvent increases to compensate for this loss, and the running cost increases. However, there was a problem that the increase of

As the above-mentioned solvent, a solvent having excellent vaporization properties is widely used in order to accelerate drying and fixing of the ink at the time of pattern formation. Examples of such a solvent include methyl ethyl ketone (MEK) and the like. It is harmful, and it is not preferable to release the vaporized solvent as described above.

The present invention has been made in view of the above circumstances, and the concentration of the ink stored in the ink tank has been reduced due to the reflux of the solvent used for cleaning the ink supply system and the recovery system including the ejection nozzle. It is an object of the present invention to provide an ink-jet recording apparatus which can prevent a decrease in ink jetting, can perform accurate printing satisfactorily over a long period of time, and can effectively reduce exhaust containing a harmful solvent.

[0024]

An ink jet recording apparatus according to a first aspect of the present invention includes a case having an ink tank and a solvent tank, a recording head having an ink jet nozzle, and a supply tube for ink and a solvent. It is connected by a connection tube that contains a collection tube,
While the ink supplied from the ink tank via the supply tube is ejected from the ejection nozzle to deflect and form a pattern on the object, the solvent supplied from the solvent tank via the supply tube causes the ejection nozzle to An ink jet recording apparatus configured to perform cleaning including an ink supply system and a recovery system, characterized in that the ink jet recording apparatus includes a reserve tank used for the cleaning and storing a solvent mixed with the ink recovered in the recovery tube. .

In the present invention, a reservoir is provided separately from the ink tank and the solvent tank provided inside the case (body case), and the solvent mixed with ink used for cleaning the ejection nozzles is supplied to the inside of the reserve tank. To prevent the concentration of the ink stored in the ink tank from decreasing. The ink-mixed solvent stored in the reserve tank as described above can be effectively used to adjust the concentration of the ink when the concentration of the ink in the ink tank changes due to evaporation of the solvent.

In an ink jet recording apparatus according to a second aspect of the present invention, a solvent mixture is connected to the reserve tank from the ink tank via the inside of the connection tube, and is recovered to the ink tank via the ink recovery tube together with the ink. An air tube for sending the air to the reserve tank, and an exhaust port that opens to the reserve tank and exhausts the air sent by the air tube.

In the present invention, the ink tank and the reserve tank are communicated with each other by an air tube extending in a connecting tube connecting the case and the recording head, and an exhaust port is provided to open to the reserve tank. The ink ejected from the ejection nozzle is introduced into an ink tank through a collection tube, and the ink is collected. On the other hand, the solvent-mixed air collected together with the ink flows through the air tube to cool, and the solvent component is cooled. Is condensed and introduced into a reserve tank, the condensed solvent is collected in the reserve tank, and the remaining air containing almost no solvent component is exhausted through the exhaust port to prevent the release of the solvent component.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a schematic diagram showing a schematic configuration of an ink jet recording apparatus according to the present invention. As shown in the drawing, an ink jet recording apparatus according to the present invention has a main body case 1 and a recording head 2 similar to the conventional apparatus shown in FIG.
Are connected by a connection tube 3.

Inside the main body case 1, an ink tank T is provided.
_1, provided with a replenisher tank T ₂ and solvent tank T _3, and these tanks T _1, T _2, T ₃ between mutually and between the ink tank T ₁ and a solvent tank T ₃ and the recording head 2 Piping (supply pipe, supply pipe 11, replenishment pipe 13, supply pipe 14, branch pipe 14a, ink recovery pipe 15, solvent recovery pipe 16) for supplying or receiving ink or solvent through Are provided with electromagnetic on-off valves V ₁ , V ₂ , V ₃ interposed. These components are the same as those of the conventional device shown in FIG. 2, and the same reference numerals are given to the same components, and detailed description is omitted. The feed pipe is
The electromagnetic valve K ₃ interposed as described below in the middle, second Okukyukama 10b of the first feed pipe 10a and the downstream side of the upstream side
And is divided into:

Inside the recording head 2, a jet nozzle 20,
A gutter 21, a charging electrode 22 and a deflecting electrode 23 are provided, and electromagnetic on-off valves K ₁ and K ₁ for switching a supply path to the injection nozzle 20.
_Two are provided. These components are the same as those of the conventional device shown in FIG.
The same components as those of the conventional injection nozzle 20 shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted.

The connecting tube 3 connecting the recording head 2 and the main body case 1 is a hollow tube made of a flexible material, and includes an ink supply tube 30, a solvent supply tube, and the like.
FIG. 2 also shows the structure of the main body case 1 and the connection with the components in the recording head 2. This is the same as the conventional device, and the common components are denoted by the same reference numerals, and detailed description is omitted. In FIG. 1, the connecting tube 3 is shown as a short tube, but the length of the connecting tube 3 is
It can be set appropriately according to the separation distance between the main body case 1 and the recording head 2.

Hereinafter, a configuration of the ink jet recording apparatus according to the present invention which is different from the conventional one will be described. Inside the main body case 1, the ink tank T ₁ and the refill ink tank T
₂ and solvent tank T ₃ and the reserve tank T _4, which is constituted separately is provided. The reserve tank T _4, the solvent recovery pipe 17 for solvent recovery are connected.
The solvent recovery pipe 17, said through an electromagnetic on-off valve K ₄ disposed downstream of the pump P ₁ is connected to the first supply pipe 10a, when the solenoid valve K ₄ is opened, 1st feed pipe
It is configured to communicate with 10a.

The solenoid on-off valve K ₄ is arranged in parallel with the other two solenoid on-off valves K ₃ and K _{5. When} the solenoid on-off valve K ₃ is opened, the first feed pipe 10 a and the second supply valve 10 are connected to each other. 2 is passed through feed pipe 10b communicate with each other, when the solenoid valve K ₅ is opened, the first supply pipe 10a is a structure in which to communicate with the discharge pipe 4 leading to the outside of the main body case 1.

[0034] During normal operation, the solenoid valve K ₃ is opened, supply pipe (first supply pipe 10a and the second delivery pipe
Ink or replenishment of solvent into the ink tank T ₁ performed by using the 10b), and supply and recovery of the excess ink of the ink to the recording head 2, and the opening of the electromagnetic valve K _3,
The operation is performed in combination with the opening and closing of the electromagnetic on-off valves V ₁ and V ₂ on the upstream side.

The opening of the solenoid on-off valve K ₄ is performed simultaneously with the opening of the solenoid on-off valve V ₃ on the upstream side. Open electromagnetic valve V ₃ is as described above, the recording head 2 has suspended the ejection of ink
The injection nozzle 20, are intended to be performed in conjunction with the opening of the recording head 2 inside the electromagnetic valve K ₂ when cleaning with a solvent which is directly supplied from the solvent tank T _3. At this time since the electromagnetic valve K ₄ is opened, the used wash, through ink solvent mingled refluxing through the solvent recovery pipe 16 from the injection nozzle 20, and an ink recovery tube 15 is trapped in the gutter 21 ink solvent mingled refluxing is introduced into the solvent recovery pipe 17 via the electromagnetic on-off valve K _4, the solvent recovery pipe 17
It is introduced into the reserve tank T ₄ communicating with the, is stored in the reserve tank T _4.

As described above, in the ink jet recording apparatus according to the present invention, the solvent mixed with the ink used for cleaning the ejection nozzle 20 is supplied to the reserve tank T provided separately from the ink tank T ₁ and the solvent tank T _{3. 4} from the reservoir is recovered, can be prevented without fear affecting the concentration of ink the solvent was stored in the ink tank T _1, the occurrence of printing failure due to viscosity reduction in advance,
Accurate pattern formation can be favorably performed over a long period of time.

A solvent discharge pipe 5 for discharging the solvent mixed with ink stored inside is connected to the bottom of the reserve tank T _4. The solvent discharge pipe 5 is connected to the electromagnetic on-off valve V
₁ , V ₂ and V ₃ are connected to the first feed pipe 10a via an electromagnetic on-off valve V ₄ arranged in parallel. Thus, when opening the electromagnetic on-off valve V ₄ during normal operation which is performed by opening the solenoid valve K _3, ink mingled solvent in the reserve tank T ₄ according to operation of the pump P _1, first , Second
Delivery line 10a, and is supplied to the ink tank T ₁ through 10b. This supply, when the solvent component contained in the ink in the ink tank T ₁ is lost by evaporation, to compensate the loss fraction, performed to properly maintain the concentration of the ink, stored in the reserve tank T ₄ The effective use of the solvent mixed with the ink.

When the inside of the reserve tank T ₄ is empty, the solenoid valve V ₂ is opened as in the conventional case,
Supply pipe 14 from the solvent tank T ₃ is communicated to the first supply pipe 10a, the ink concentration in the ink tank T ₁ is optimized by the supply of the solvent in the solvent tank T _3. In the ink jet recording apparatus of the present invention as described above it is collected in a reserve tank T _4, the solvent reservoir ink mingled, because effectively utilized for the ink tank T ₁ inside the ink density adjustment, the consumption of the solvent Thus, the running cost can be reduced.

On the other hand, when the electromagnetic on-off valve K ₅ to open the solenoid valve V ₄ when in the open state, the ink mingled solvent in the reserve tank T ₄ according to operation of the pump P _1, a solvent discharge pipe 5. The liquid is discharged to the outside via the first supply pipe 10a and the drain pipe 4. Also the bottom of the ink tank T _1, is connected to the ink discharge pipe 6 for discharging the ink stored therein, the ink discharge tube 6, the electromagnetic on-off valve _{V 1, V 2, V 3} , is connected to the first supply pipe 10a through the electromagnetic on-off valve V ₅ juxtaposed to V _4. Therefore, the when the solenoid valve K ₅ opens the solenoid valve V ₅ when in the open state, the ink in the ink tank T ₁ is the operation of the pump P _1, the ink discharge tube 6, the first feed The liquid is discharged to the outside via the pipe 10a and the drain pipe 4.

[0040] Further, when opening the solenoid on-off valve V ₁ when the solenoid valve K ₅ is in an open state, it is possible to discharge the replenishing ink in the refilling ink tank T _2, likewise electromagnetic on-off valve V
When opening the _2, it is possible to discharge the solvent in the solvent tank T _3. In the ink jet recording apparatus of the illustrated, by providing the drainage tube 4 communicating with the first feed pipe 10a via the solenoid valve K _5, solenoid valve V _1, V
₂ , V ₄ and V ₅ can be selectively opened and closed to discharge the ink, the solvent, and the solvent mixed with the ink stored in each of the tanks separately or appropriately in combination. The old ink, the solvent, and the solvent mixed with the ink can be selectively and easily replaced.

Further ink jet recording apparatus according to the present invention includes an air tube 18 having one end connected to the upper portion of the ink tank T _1, and an air tube 19 having one end connected to the upper part of the reserve tank T _4, these Is connected to air tubes 34 arranged inside the connecting tube 3 so as to reciprocate between the main body case 1 and the recording head 2, and these air tubes 18, 34, 19 An air tube is connected from the ink tank T ₁ to the reserve tank T ₄ via the inside of the connecting tube 3. Also the reserve tank T _4, the exhaust pipe 12 to an exhaust port opened is connected to the upper portion, the upper portion of the air in the reserve tank T ₄ is, it is constituted to be discharged to the outside through the exhaust pipe 12.

With the above configuration, during operation as described above,
Ink and air trapped in the recording head 2 inside the gutter 21, the pump is sucked by the operation of P _1, ink recovery tube 32, and the first ink tank T ₁ through the second delivery line 10a, and 10b When introduced into the ink tank T
_{In 1} , only the ink is collected, and the remaining air is led out to the air tube 18, flows through the air tubes 34 and 19, and is introduced into the reserve tank T ₄ .

Since the air tube 34 is provided inside the connecting tube 3 remote from the main body case 1, the air flowing through the inside is effectively cooled by heat exchange with the outside air. is, the majority of the solvent contained in the air is caused to condense and liquefy, will be introduced into the reserve tank T ₄ via the air tube 19, liquefied solvent is added dropwise to the reserve tank T ₄ Only the air that has been collected and contains almost no solvent is discharged to the outside through the exhaust pipe 12.

As described above, in the present invention, the air tube connected from the ink tank T ₁ to the reserve tank T ₄ via the inside of the connecting tube 3 is provided, so that the solvent discharged to the outside of the main body case 1 together with the exhaust gas is provided. Since the amount of the solvent is greatly reduced, unnecessary consumption of the solvent can be eliminated, the running cost can be reduced, and the surrounding environment can be prevented from being polluted by the discharge of the harmful solvent.

As shown, the connection between the air tubes 18 and 19 and the air tube 34 is made via connectors C ₁ and C ₂ having connection ports for the respective tubes on each side.
The connector C _1, the feed pipe 11, provided with a branch pipe 14a, the ink recovery tube 15, and the connection port of the solvent recovery pipe 16, connector C _2, the ink supply tube 30, the solvent supply tube 31, the ink collection tube 32 and solvent recovery tube
33 connection ports, connecting the supply pipe 11 to the ink supply tube 30, connecting the branch pipe 14a to the solvent supply tube 31, connecting the ink recovery pipe 15 to the ink recovery tube 32, and connecting the solvent recovery pipe The connection between 16 and the solvent recovery tube 33 is also made via the connectors C ₁ and C ₂ .

[0046] That is, in the ink jet recording apparatus illustrated by attachment and detachment of the connector C _1, C _2, the connection tube 3 and the recording head 2 can be easily attached to and detached from the main body case 1, the recording head 2 When various troubles such as an operation failure occur, the recording head 2 having the trouble can be removed, and the replacement work for mounting a new recording head 2 can be easily performed. In addition, connecting tube 3
Are the components of the recording head 2 (the ejection nozzle 20, the charging electrode 22,
Various electric wirings, such as a power supply line for supplying power to the deflection electrode 23) and a signal line for transmitting a control signal from a control unit (not shown) provided inside the main body case 1 to each unit of the recording head 2 are also included. The connection of these electric wires is also made by the connector C
It can be performed in conjunction with _1, C _2. In this case, the replacement work is further facilitated. The connector for connecting the electric wiring may be provided separately from the connectors C ₁ and C ₂ .

A pressure sensor 7 for detecting the internal pressure is provided in the middle of the solvent recovery pipe 16. During the normal operation, the solvent recovery pipe 16 is a pipe closed by closing the electromagnetic on-off valve V ₃ , and the internal pressure of the pipe is controlled by the injection nozzle inside the recording head 2 which is communicated via the solvent recovery tube 33. Equal to 20 internal pressure. That is, the pressure detected by the pressure sensor 7 is the pressure of the ink about to be injected from the injection nozzle 20, the detected pressure is fed back to the pump P ₂ for feeding the ink, the pump P ₂
Is used to control the discharge pressure of the liquid. This control is performed by the operation of a control unit (not shown) provided in the main body case 1, whereby it is possible to accurately manage the internal pressure of the ejection nozzle 20, that is, the speed of the ink ejected from the ejection nozzle 20. It becomes possible.

The ink jet recording apparatus shown in FIG. 1 has a tipping sensor 8 at an appropriate position inside the main body case 1. The tipping sensor 8 includes, for example, a pendulum pivotally supported on a horizontal support shaft and a rotation sensor for detecting the rotation of the support shaft. The swing of the pendulum accompanying the above is detected by a change in the output of the rotation sensor. The output of the fall sensor 8 is given to a control unit (not shown) inside the main body case 1. When the control unit recognizes that the main body case 1 has fallen by the input from the fall sensor 8, the main body case 1 In order to prevent leakage of ink or solvent to the outside of the pump, for example, a stop signal is supplied to each of the pumps P ₁ , P ₂ , P ₃ , and the solenoid on-off valves V _{1 to} V ₅ and K ₃
~K ₅ respectively into a closure signal respectively emitted, and performs an operation of an emergency stop the operation described above.

Further, the ink jet recording apparatus shown in FIG. 1 is provided with bypass pipes L ₂ and L ₃ which respectively communicate upper and lower portions of the replenishment ink tank T ₂ and the solvent tank T ₃ .
These bypass pipes L ₂ and L ₃ are provided so as to be visible from the outside of the main body case 1 and are used as level meters for knowing the liquid level in the respective tanks T ₂ and T ₃ . ing. The replenishment ink tank T ₂ and the solvent tank T ₃ are made of polypropylene resin because they are easy to mold and inexpensive, but the bypass pipes L ₁ , L ₂
The case of a polypropylene resin, in particular, in the bypass pipe L ₂ utilized as a level meter replenisher tank T _2, there is a possibility that adhering ink on the inner surface can not be visually recognized liquid level from the outside. Therefore, a fluororesin pipe such as Teflon (trade name) is used as the bypass pipes L ₂ and L ₃ so that level detection can be performed reliably.

Similarly, the pipes in the main body case 1 and the respective tubes in the connecting tube 3 are also made of fluororesin pipes or tubes so as to reduce the flow resistance inside each of them.

[0051]

As described in detail above, in the ink jet recording apparatus according to the first aspect of the present invention, a reserve tank is provided inside a case having an ink tank and a solvent tank, and a solvent mixed with ink used for cleaning the ejection nozzle is removed. Since it is configured to be stored in the reserve tank without returning to the ink tank, there is no danger that the concentration of the stored ink in the ink tank is reduced due to the effect of the solvent used for cleaning the ejection nozzle, and accurate printing is performed. It can be performed well over a long period of time.

In the ink jet recording apparatus according to the second aspect of the present invention, the ink jet recording apparatus is provided with an air tube connected from the ink tank to the reserve tank via the inside of the connection tube, and an exhaust port opened to the reserve tank. The solvent-mixed air collected in the collection tube together with the ink is cooled while flowing through the air tube, whereby the condensed solvent component is collected in the reserve tank, and air containing no solvent flows through the exhaust port. To prevent unnecessary release of the solvent,
By reducing solvent consumption and running cost,
In addition, the present invention has excellent effects, such as prevention of deterioration of the surrounding environment due to release of harmful solvents.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram illustrating a schematic configuration of a conventional inkjet recording apparatus.

FIG. 3 is a schematic diagram showing a schematic configuration of an injection nozzle.

[Explanation of symbols]

1 main body case 2 recording head 3 connecting tube 18 air tube 19 air tube 20 injection nozzle 34 air tube T ₁ ink tank T ₂ replenisher tank T ₃ solvent tank T ₄ reserve tank

Continued on the front page (72) Inventor Makoto Sakai 1-33-1 Higashinakajima, Higashiyodogawa-ku, Osaka-shi, Osaka Inside Keyence Co., Ltd. (72) Inventor Hideaki Kamiuchi 1-3-14 Higashinakajima, Higashiyodogawa-ku, Osaka-shi, Osaka F-term in KEYENCE CORPORATION (reference) 2C056 EA06 EA14 EA16 EA19 EA24 EB34 EB55 EC18 EC44 FA05 JB15 JC01 JC05 JC06 JC13 KA01 KB04 KB08 KB16 KB19 KB21 KB26 KC02 KC16 KD01

Claims (2)

[Claims] 1. A case including an ink tank and a solvent tank, and a recording head including an ink ejection nozzle.
The ink and the solvent are connected by a connecting tube containing a supply tube and a recovery tube, and the ink supplied from the ink tank via the supply tube is deflected while being ejected from the ejection nozzle to form a pattern on an object. In an ink jet recording apparatus configured to wash the ejection nozzles, including a supply system and a recovery system of the ink, with a solvent supplied from the solvent tank via a supply tube, the inkjet nozzle is used for the cleaning, and the recovery tube An ink jet recording apparatus comprising a reserve tank for storing a solvent mixed with ink to be collected. 2. An air tube connected to the reserve tank from the ink tank via the inside of the connection tube, and for feeding solvent-mixed air to the reserve tank through the ink collection tube and collected together with the ink through the ink collection tube. 2. The ink jet recording apparatus according to claim 1, further comprising: an exhaust port opened to the reserve tank, and configured to exhaust air sent from the air tube.