JP2019018408A - Liquid discharge device and liquid discharge method - Google Patents

Abstract

To provide a liquid discharge device which attains good discharge performance without performing purge, maintains a good state of a nozzle surface over a long period even if high hardness fine particles are included in discharge liquid, and maintains a good discharge state over a long time.SOLUTION: A liquid discharge device includes a liquid discharge head which discharges a liquid containing a solvent from a nozzle surface and includes: a capping member which caps the nozzle surface of the liquid discharge head; and a wiping member which wipes the nozzle surface of the liquid discharge head. The capping member can retain the solvent in the interior and/or on its surface and caps the nozzle surface while retaining the solvent. The wiping member can retain the solvent in the interior and/or on its surface and wipes the nozzle surface in a state of retaining the solvent.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an apparatus for ejecting liquid and a liquid ejection method.

In recent years, in the field of precision coating, attempts have been made to use an inkjet head to apply only to a necessary place, or to reduce the amount of paint that is unpainted and splashes wastefully.
Ink jet heads have the above-mentioned advantages over spray nozzles, but in paints used for painting, highly volatile solvents and functional paints in which various fine particles are dispersed are often used. Therefore, the number of nozzles is larger than that of spray nozzles, the nozzle diameter is small, and nozzle clogging is likely to occur when the above-described paint is used.
Therefore, there are the following as conventional techniques for solving the above problems.

Japanese Patent Laid-Open No. 2004-133867 discloses that after the ink on the nozzle surface is wiped with an ink receiving member having a plurality of protrusions, the nozzle surface is wiped while the roller-shaped wipe member rotates.
However, in Patent Document 1, the nozzle surface is wiped with an ink receiving member having a plurality of protrusions, but the head surface is wiped in a state in which a large amount of discharge liquid containing fine particles of high hardness has oozed out. In this case, there is a problem that the head life is shortened due to scratches caused by the fine particles adhering to the periphery of the nozzle hole due to repeated rubbing.
In addition, even when wiping while rotating with a roller member, the solute (resin and fine particles) of the discharge liquid adhering to the nozzle surface cannot be completely removed, and thus unstable discharge such as non-discharge and discharge bending is likely to occur.

Japanese Patent Application Laid-Open No. 2004-228561 is a method of wiping a head from a droplet discharge head while feeding a wiping sheet coated with a cleaning liquid uniformly using a roll mechanism.
However, in Patent Document 2, cleaning is performed while rubbing the head surface with a wiping sheet. However, when the head surface is wiped off in a state where a large amount of discharge liquid containing fine particles of high hardness has oozed out, the surface is rubbed repeatedly. As a result, there is a problem in that the periphery of the nozzle hole is damaged by the fine particles adhering thereto, and the life of the head is shortened.
In addition, in order to completely wipe out a large amount of the discharged discharge liquid with a thin wiping sheet, it is necessary to wipe off while feeding a large amount of sheets, which consumes a large amount of wiping sheets and increases costs.

In Patent Document 3, when discharging is stopped, a plate-like or tube-like cap made of a solvent-resistant material is immersed in a solvent and then brought into close contact with the head, and the nozzle is blocked from outside air to evaporate the droplet material. It prevents clogging and realizes stable ejection.
However, in Patent Document 3, since the cap uses a fluororesin-based material that does not absorb liquid, if the material adheres directly to the nozzle surface, it is a discharge liquid that uses a particularly high volatile solvent as a solvent. Solvent volatilization causes solutes (resin and fine particles) in the discharge liquid to stick around the nozzle holes, and unstable discharge such as non-discharge and discharge bending is likely to occur.
In addition, after discharging the head from the cap, it discharges without wiping, etc. In the case of a discharge liquid containing fine particles, when the head moves away from the cap, a large amount of fine particles are generated around the nozzle hole. These may interfere with the discharge stability of the discharge liquid and may cause non-discharge or unstable discharge.

In Patent Document 4, the felt laminated on the surface of the wiping member is supplied with a solvent from a solvent tank and impregnated. Scratch off. Further, the wiping member is rubbed in a solvent with a brush to prevent re-contamination of the nozzle surface.
However, in Patent Document 4, since the head surface is cleaned while being rubbed, there is a problem in that the head life is shortened as in Patent Documents 1 and 2.

In Patent Document 5, since the ink suction operation can be performed only on the nozzles that need to be sucked by changing the length of the nozzle row covered by the sealing means, the ink consumption can be suppressed, the running cost can be reduced, Short-time suction is possible.
However, in Patent Document 5, in the case of a discharge liquid that is a highly volatile solvent and contains fine particles, a large amount of fine particles adhere to the periphery of the nozzle hole only by suction, and these are the discharge stability of the discharge liquid. May cause non-ejection or unstable ejection.
In addition, wiping with a wiper blade is performed after suction, but if the wipe is performed after a period of time after the suction operation, the solvent volatilizes and thickens, and the nozzle surface is rubbed with a large amount of fine particles remaining. As in References 1 and 2, there is a problem that the head life is shortened.

  As described above, the above-described prior art cannot sufficiently cope with a discharge liquid containing a highly volatile solvent and high hardness fine particles, and it is difficult to perform stable discharge from an inkjet head, and the life of the head Cannot solve the problem of extremely short.

  In Patent Documents 1 to 4, before the head nozzle surface is wiped, it is necessary to discharge a large amount of paint by purging in order to discharge the thickened paint and bubbles in the nozzle hole. Therefore, a large amount of expensive functional paint is discarded, resulting in high cost. Moreover, since it is a blade wipe, there also exists a problem that it cannot wipe off neatly.

  According to the present invention, good dischargeability can be obtained without purging, and even when the discharge liquid contains high-hardness fine particles, the nozzle surface is kept in a good state for a long time, and a good discharge state is kept for a long time. An object of the present invention is to provide an apparatus for ejecting liquid.

  In order to solve the above-mentioned problem, the present invention is an apparatus for discharging a liquid including a liquid discharge head for discharging a liquid containing a solvent from a nozzle surface, and a capping member that caps the nozzle surface of the liquid discharge head; A wiping member for wiping the nozzle surface of the liquid discharge head, and the capping member can hold the solvent inside and / or on the surface, and caps the nozzle surface while holding the solvent, The wiping member is capable of holding the solvent inside and / or on the surface, and wipes the nozzle surface while holding the solvent.

  According to the present invention, good discharge properties can be obtained without purging, and even when high-hardness fine particles are contained in the discharge liquid, the nozzle surface is kept in a good state for a long time, and a good discharge state for a long time. Can keep.

It is the schematic for demonstrating an example of the capping member in an example of the apparatus which discharges the liquid of this invention. It is the schematic for demonstrating an example of the wiping member in an example of the apparatus which discharges the liquid of this invention. It is the schematic for demonstrating the example of the wiping in FIG. It is the schematic for demonstrating the other example of the wiping member in an example of the apparatus which discharges the liquid of this invention. It is the schematic for demonstrating the example of the wiping in FIG. It is a principal part plane schematic in an example of the apparatus which discharges the liquid of this invention. It is a principal part side surface schematic in the apparatus of FIG. It is the schematic in the other example of the apparatus which discharges the liquid of this invention. It is the schematic in the other example of the apparatus which discharges the liquid of this invention. It is the schematic for demonstrating the liquid circulation mechanism in an example of the apparatus which discharges the liquid of this invention. It is the schematic (a)-(c) in the other example of a capping member. It is the schematic (a)-(d) for demonstrating the structure of the comparative example 1, and operation | movement. 6 is a schematic diagram for explaining a configuration of Comparative Example 2. FIG. It is a photograph which shows the discharge state in Examples 1-3 and Comparative Examples 1 and 2 immediately after discharge and with time.

  Hereinafter, an apparatus and a liquid discharge method for discharging a liquid according to the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below, and other embodiments, additions, modifications, deletions, and the like can be changed within a range that can be conceived by those skilled in the art, and any aspect is possible. As long as the functions and effects of the present invention are exhibited, the scope of the present invention is included.

  An apparatus for ejecting a liquid according to the present invention is an apparatus for ejecting a liquid including a liquid ejection head for ejecting a liquid containing a solvent from a nozzle surface, the capping member for capping the nozzle surface of the liquid ejection head, and the liquid And a wiping member for wiping the nozzle surface of the discharge head, wherein the capping member can hold the solvent inside and / or on the surface, caps the nozzle surface while holding the solvent, and the wiping The member is capable of holding the solvent inside and / or on the surface, and wipes the nozzle surface while holding the solvent.

  Further, the liquid discharge method of the present invention is a liquid discharge method in which a liquid containing a solvent is discharged from a nozzle surface by a liquid discharge head, wherein the liquid discharge head includes a discharge step of discharging the liquid and a capping member. A capping step of capping the nozzle surface of the liquid, and a wiping step of wiping the nozzle surface of the liquid discharge head by a wiping member, the capping member can hold the solvent inside and / or on the surface, The nozzle surface is capped while holding the solvent, and the wiping member can hold the solvent inside and / or on the surface, and wipes the nozzle surface while holding the solvent. To do.

<Liquid>
The liquid (also referred to as ejection liquid or ink) ejected by the liquid ejection head contains a solvent and, if necessary, other components.
The solvent can be appropriately changed, and examples thereof include tetrahydrofuran (THF), cyclohexanone (anone), cyclopentanone, and the like. These may use 1 type and may use 2 or more types.

Examples of other components include resins and fine particles.
Examples of the resin include polycarbonate resins and acrylic monomers.

The liquid discharged from the liquid discharge head may appropriately contain fine particles, particularly high hardness fine particles, for the purpose of increasing the durability of the coating film after discharge.
Examples of the fine particles include ceramic fine particles.
Examples of the ceramic fine particles include alumina and zirconia.

  Further, the liquid to be ejected is not particularly limited as long as it has a viscosity and surface tension that can be ejected from the head. However, the liquid has a viscosity of 30 mPa · s or less at room temperature, normal pressure, or by heating and cooling. It is preferable that More specifically, solvents such as water and organic solvents, colorants such as dyes and pigments, functional materials such as polymerizable compounds, resins, and surfactants, and biocompatible materials such as DNA, amino acids, proteins, and calcium. , Edible materials such as natural pigments, solutions, suspensions, emulsions, and the like. These include, for example, inkjet inks, surface treatment liquids, components of electronic devices and light emitting devices, and formation of electronic circuit resist patterns. It can be used in applications such as liquids for use and three-dimensional modeling material liquids.

<Capping member>
Next, a capping member that caps the nozzle surface of the liquid discharge head will be described.
The capping member of the present embodiment can hold the solvent inside and / or on the surface, and caps the nozzle surface while holding the solvent. The capping member is preferably capable of holding the solvent inside and on the surface.
When capping, at least one or a part of the inside or the surface of the capping member may hold the solvent.

In the present embodiment, the solvent held by the capping member is not the use of a dedicated cleaning liquid, but is the same component as the solvent contained in the discharge liquid. The discharge liquid contains a solvent and other components such as particles as required, but the capping member holds the solvent contained in the discharge liquid. Therefore, in the present invention, the solvent held by the capping member is different from the solvent contained in another liquid such as a cleaning liquid.
Further, if there is a change in the solvent contained in the discharge liquid, it is possible to change the solvent held by the capping member in accordance with the change.

Although it does not restrict | limit especially as a shape of a capping member, For example, a block shape is mentioned. The size is not particularly limited as long as it can cap the nozzle surface.
When the capping member caps the nozzle surface, it is preferable that the capping member is in close contact with the nozzle surface. However, a part of the capping member may be in close contact with the capping member.

The material of the capping member is appropriately changed depending on the solvent used and is not particularly limited, and examples thereof include polyvinyl alcohol (PVA) and fluororesin.
Further, the capping member is preferably a porous sponge having a liquid absorbing property, and in this case, the solvent can be easily retained.
In the case of urethane, olefin, etc., for example, when a polar solvent is used, care should be taken because it may be dissolved by the solvent.

The average value of the mesh diameter of the capping member is preferably 30 to 100 μm. In the case of the above range, there is an advantage that the liquid can be absorbed quickly without clogging.
When the discharge liquid contains high-hardness fine particles, the average value of the mesh diameter of the capping member is preferably larger than the particle diameter of the high-hardness fine particles. In this case, when high-hardness fine particles are attached to the nozzle surface, it is easy to move to the capping member side, and the nozzle surface can be made in a cleaner state.

<Wiping member>
Next, a wiping member for wiping the nozzle surface of the liquid discharge head will be described.
The wiping member of the present embodiment can hold the solvent inside and / or on the surface, and wipes the nozzle surface while holding the solvent (also referred to as wiping). The wiping member is preferably capable of holding the solvent inside and on the surface.
When wiping, at least one or a part of the inside and the surface of the wiping member may hold the solvent.

In this embodiment, the solvent that the wiping member holds is not the use of a dedicated cleaning liquid, but is the same component as the solvent contained in the liquid. The liquid contains a solvent and other components such as particles as required, but the wiping member holds the solvent contained in the liquid. Therefore, in the present invention, the solvent held by the wiping member is different from the solvent contained in another liquid such as a cleaning liquid.
Further, if there is a change in the solvent contained in the liquid, it is possible to change the solvent to be held by the wiping member accordingly.

  The shape of the wiping member is not particularly limited, and examples thereof include a roller shape and a block shape. The size is not particularly limited as long as the nozzle surface can be wiped off.

The material of the wiping member is appropriately changed depending on the solvent to be used and is not particularly limited, and examples thereof include polyvinyl alcohol (PVA) and fluororesin.
Further, the wiping member is preferably a porous and liquid-absorbing sponge, and in this case, the solvent can be easily retained.
In the case of urethane, olefin, etc., for example, when a polar solvent is used, care should be taken because it may be dissolved by the solvent.

  The average value of the mesh diameter of the wiping member is preferably 10 to 100 μm. If it is too large, the material becomes coarse and it is difficult to perform sufficient wiping, and if it is too small, the take-in speed of the hard liquid particles in the discharge liquid and the discharge liquid becomes slow, making it difficult to perform sufficient wiping.

<Description of effects>
A mechanism by which the effect of the present invention can be obtained by the above configuration will be described.
The nozzle surface can be prevented from drying by capping the capping member on the nozzle surface of the liquid discharge head during standby before discharging the discharge liquid. In addition to this, by using a capping member that holds the solvent contained in the discharge liquid, the liquid that oozes from the nozzle surface by the permeation action (discharge liquid) can be appropriately permeated into the capping member. It is possible to prevent the thickened discharge liquid from adhering to the periphery of the nozzle hole.

  Even when high-hardness fine particles are contained in the discharge liquid, the number of high-hardness fine particles adhering to the nozzle surface and the periphery of the nozzle hole can be reduced, and when wiping with a wiping member, the nozzle surface is damaged by the high-hardness fine particles. Can be suppressed. Thereby, the nozzle surface can be kept in a good state for a long time, and a good discharge state can be maintained for a long time.

  Further, when the liquid discharge head is separated from the capping member, a small amount of discharge liquid oozes out on the nozzle surface due to the capillary phenomenon of the discharge liquid in the nozzle hole. In this embodiment, since the nozzle surface is wiped by the wiping member that holds the solvent, the discharge liquid that has slightly oozed out of the nozzle surface is sucked and wiped off at the same time. For this reason, the nozzle surface can be easily cleaned.

  In addition, a small amount of high-hardness fine particles adhering to the nozzle surface can easily move to the wiping member side, and the amount of high-hardness fine particles adhering to the nozzle surface can be further reduced. This can be further suppressed, and good dischargeability can be maintained over a long period of time.

As described above, since the discharge liquid is prevented from thickening and drying in the nozzle hole and the peripheral part of the nozzle hole, and the nozzle surface can be kept clean, in order to discharge the thickened discharge liquid in the nozzle hole No clogging of the nozzle holes can be suppressed without purging. As described above, according to the present embodiment, good ejection performance can be obtained without purging.
Furthermore, since no purge is required, it is possible to significantly reduce the consumption of expensive discharge liquid, which is advantageous in terms of cost.

  In addition, since the amount of discharge liquid adhering to the nozzle surface is extremely small compared to when purging, when the discharge liquid contains high-hardness fine particles, the amount of high-hardness fine particles adhering to the nozzle surface is also extremely small. Slightly. For this reason, it is possible to prevent the nozzle surface from being damaged at the time of wiping, and it is possible to maintain good ejection properties over a long period of time.

<Adjustment of solvent retention>
The apparatus for ejecting liquid according to the present embodiment preferably includes a holding amount adjusting unit that adjusts the holding amount of the solvent held by the capping member or the wiping member.
The holding amount adjusting unit of the present embodiment includes a solvent supply unit that supplies the solvent to the capping member or the wiping member, and a pressing unit that presses the capping member or the wiping member.
By pressing the capping member or the wiping member with the pressing portion, it is possible to squeeze out the discharge liquid or solvent held by the capping member or the wiping member.
The holding amount adjustment unit of the present embodiment will be described with reference to the drawings.

<< Embodiment of Capping Member >>
First, an example in the case of a capping member will be described with reference to FIG.
In FIG. 1, a block-shaped capping member 32, a throttle block 34 as a pressing portion, a fixing base 38 having a liquid discharge hole 36 and a punch hole 37 are illustrated.

  In the present embodiment, when the liquid discharge head is separated from the capping member 32, the solvent supply unit drops the solvent onto the capping member 32 and presses it with the throttle block 34. Can be squeezed out together. By periodically performing the squeezing operation, the capping member 32 can be kept clean for a long time.

  Further, by supplying the solvent by the solvent supply unit and squeezing out excess solvent by the squeezing block 34, the amount of the solvent held by the capping member 32 can be set within a desired range. If the amount of the solvent held by the capping member is large, there is a concern that the solvent may enter the nozzle of the liquid discharge head and adversely affect the discharge. On the other hand, if the amount of solvent held by the capping member is small, thickening and drying of the discharged liquid may not be prevented.

  In the present embodiment, the capping member 32 is installed on the fixed base 38 having a mesh bottom, and the mesh bottom functions as the liquid discharge hole 36. Therefore, the squeezed solvent is appropriately used as a punch hole. 37 passes through the liquid discharge hole 36.

  The material of the aperture block 34 is not particularly limited, but is preferably harder than the capping member 32, and examples thereof include a material made of metal.

  The solvent supply unit is not particularly limited, and can be appropriately changed. In the present embodiment, the solvent is dropped onto the capping member 32 when the capping member is separated from the liquid ejection head, but the present invention is not limited to this. For example, the solvent may be supplied while the capping member 32 is in close contact with the liquid ejection head.

  The amount of the solvent to be held by the capping member varies depending on the configuration of the liquid ejection head and ink, the type of the capping member, the type of the solvent, and the like. be able to.

<< Embodiment of Wiping Member (1) >>
Next, the example in the case of a wiping member is demonstrated using FIG. 2, FIG.
In FIG. 2, a solvent pool 48 having a roller-like wiping member 42, a squeezing roller 44, and a liquid discharge hole 46 is illustrated.
The solvent pool 48 stores the same solvent as that contained in the discharge liquid, and is installed so that the lower portion of the wiping member 48 is immersed in the solvent in the solvent pool 48.

  In the present embodiment, the roller-shaped wiping member 42 is installed on a rotating shaft to which a motor 41 that rotates or fixes the wiping member 42 is connected, and is appropriately rotated and fixed. The squeezing roller 44 is pressed against the roller-shaped wiping member 42 and is rotated along with the rotation of the wiping member 42.

  By rotating the motor 41 and rotating the wiping member 42, the portion of the wiping member 42 in which the solvent is immersed is pressed against the squeezing roller 44, and excess solvent can be squeezed out. Thereby, the amount of the solvent held by the wiping member 42 in the roller-shaped circumferential direction can be kept constant, and the removability of the discharged liquid that has oozed out on the nozzle surface during wiping can be improved. Further, if wiping is performed while a large amount of solvent is immersed in the wiping member 42, there is a concern that the solvent may enter the nozzle of the liquid discharge head and adversely affect the discharge, but this can be prevented. it can.

  Furthermore, according to this embodiment, in addition to keeping the amount of the solvent held by the wiping member 42 constant as described above, the discharged liquid wiped by the wiping member 42 by wiping is also washed. Thereby, wiping can be performed in a clean state over a long period of time.

  The amount of the solvent to be held by the wiping member varies depending on the configuration of the liquid discharge head and the ink, the type of the wiping member, the type of the solvent, and the like. It can be 3 ml.

  The solvent squeezed out by the squeezing roller 44 moves to the solvent pool 48 and is discharged from the liquid discharge hole 46 as necessary. The amount of solvent in the solvent pool 48 can be adjusted as appropriate.

The material of the squeeze roller 44 is not particularly limited, but is preferably harder than the wiping member 42, and examples thereof include a material made of metal.
The size of the squeezing roller 44 is not particularly limited and can be changed as appropriate.

  Next, FIG. 3 is a diagram for explaining an example of wiping in FIG. In FIG. 3, in addition to FIG. 2, a liquid discharge head 60 is shown. The arrow in the figure indicates the wiping direction, and the nozzle surface is wiped as the wiping member advances in the direction of the arrow.

  In this embodiment, in FIG. 2, when the wiping member 42 is rotated and the portion where the solvent is squeezed reaches the apex of the wiping member 42, the rotation of the motor 41 is stopped and locked at the same time, and the wiping member 42 does not rotate. Like that. Then, the liquid ejection head is wiped in a state where the rotation of the wiping member 42 is locked.

  In this way, by wiping the nozzle surface of the liquid ejection head in the locked state, the wiping member 42 can be wiped at a portion where the amount of the solvent held is appropriately adjusted, and there is a lot of solvent and the nozzle hole It is possible to prevent penetration into the interior and insufficient wiping due to a small amount of solvent. Further, by fixing the rotation of the wiping member 42, it is possible to stabilize the removability of the discharged liquid that has oozed out on the nozzle surface.

Furthermore, the nozzle surface is wiped at the portion where the wiping member 42 is cleaned, and the removability of the discharged liquid can be further improved.
Further, according to the present embodiment, the amount of the solvent held by the wiping member 42 can be kept constant over a long period of time, and the wiping member 42 can be washed, so that the wiping member can be reused without being disposable. Therefore, it is advantageous in terms of cost.

  Further, since the wiping member 42 has a roller shape, the roller wipes linearly with respect to the nozzle surface, so that there is an advantage that the head contact becomes more reliable.

<< Embodiment (2) of Wiping Member >>
Next, another example in the case of a wiping member will be described with reference to FIGS.
In FIG. 4, a fixing base 58 having a block-like wiping member 52, a throttle block 54, and a liquid discharge hole 56 is illustrated.

In the present embodiment, the block-like wiping member 52 is installed on the fixed base 58, and the diaphragm block 54 as a pressing portion is pressed against the wiping member 52.
In this embodiment, before wiping the liquid discharge head, the solvent is dropped onto the wiping member 52 by the solvent supply unit, and the squeezing block 54 is pressed against the wiping member 52 to squeeze the solvent, thereby holding the wiping member 52. The amount of solvent can be kept constant. For this reason, by wiping on the surface where the amount of the solvent retained is kept constant, the removability of the discharged liquid that has oozed out on the nozzle surface can be stabilized. If wiping is performed in a state where the wiping member 52 holds a large amount of solvent, there is a concern that the solvent held in the wiping member may enter the nozzle hole and adversely affect the discharge, but this can be prevented. it can.

  In the present embodiment, the solvent is dropped onto the wiping member 52 and the squeezing block 54 is pressed to squeeze the discharged liquid wiped off by the wiping member 52 together with the solvent. Therefore, the wiping member 52 can be cleaned, and the nozzle surface can be wiped in a clean state. Moreover, by performing regularly, the wiping member 52 can be maintained in a clean state for a long period of time, and the nozzle surface can be maintained in a clean state for a long period of time.

  When the throttle block 54 is pressed against the wiping member 52, the wiping member 52 is pressed against the mesh 57 provided between the liquid pool 59 and the discharged liquid or solvent moves to the liquid pool 59. And it discharges | emits from the liquid discharge hole 56 suitably as needed.

  Next, FIG. 5 is a diagram for explaining an example of wiping in FIG. In FIG. 5, in addition to FIG. 4, a liquid discharge head 60 is shown. The arrow in the figure indicates the wiping direction, and the nozzle surface is wiped as the wiping member advances in the direction of the arrow.

  By the above, the amount of the solvent to be retained is adjusted moderately, and by wiping with the cleaned wiping member 52, the discharge liquid can be stably removed, and the solvent penetrates into the nozzle hole due to the large amount of solvent. It is possible to prevent the wiping operation from being performed sufficiently due to a small amount of solvent.

  According to the present embodiment, the amount of the solvent held by the wiping member 52 can be kept constant over a long period of time, and the wiping member 52 can be washed. Therefore, the wiping member can be reused without being disposable. This is also advantageous in terms of cost.

  Further, since the wiping member 52 has a block shape, there is an advantage that it is possible to make contact with the nozzle surface on a wide surface.

<< Other Embodiments >>
Next, other embodiments will be described.
The holding amount adjusting unit in the above embodiment has a solvent supply unit and a pressing unit, but is not limited to this in the present invention. For example, it is possible to adjust the amount of the solvent retained by supplying the solvent to the capping member or the wiping member by the solvent supply unit and then sucking or drying the solvent.

  In the above-described embodiment, the capping member and the wiping member are separate members. However, a configuration as a single member that can perform both capping and wiping is also possible. For example, the liquid ejection head can be wiped with a block-shaped capping member shown in FIG.

<Basic configuration of device for discharging liquid>
Next, the basic configuration of the apparatus for ejecting liquid according to the present invention will be described with reference to FIGS. FIG. 6 is a schematic plan view of a main part of the apparatus for discharging a liquid according to the present embodiment, and FIG.
The apparatus of the present embodiment is a serial type apparatus, and the carriage 403 reciprocates in the main scanning direction by the main scanning movement mechanism 493. The main scanning movement mechanism 493 includes a guide member 401, a main scanning motor 405, a timing belt 408, and the like. The guide member 401 spans the left and right side plates 491A and 491B and holds the carriage 403 so as to be movable. The carriage 403 is reciprocated in the main scanning direction by the main scanning motor 405 via the timing belt 408 spanned between the driving pulley 406 and the driven pulley 407.

  A liquid discharge unit 440 in which the liquid discharge head 404 and the head tank 441 are integrated is mounted on the carriage 403. The liquid discharge head 404 of the liquid discharge unit 440 discharges, for example, yellow (Y), cyan (C), magenta (M), and black (K) liquids. The liquid ejection head 404 is mounted with a nozzle row composed of a plurality of nozzles 411 arranged in the sub-scanning direction orthogonal to the main scanning direction and the ejection direction facing downward.

  The liquid stored in the liquid cartridge 450 is supplied to the head tank 441 by the supply mechanism 494 for supplying the liquid stored outside the liquid discharge head 404 to the liquid discharge head 404.

  The supply mechanism 494 includes a cartridge holder 451 that is a filling unit for mounting the liquid cartridge 450, a tube 456, a liquid feeding unit 452 including a liquid feeding pump, and the like. The liquid cartridge 450 is detachably attached to the cartridge holder 451. Liquid is fed from the liquid cartridge 450 to the head tank 441 by the liquid feeding unit 452 via the tube 456.

  This apparatus includes a transport mechanism 495 for transporting the paper 410. The transport mechanism 495 includes a transport belt 412 serving as transport means, and a sub-scanning motor 416 for driving the transport belt 412.

  The conveyance belt 412 adsorbs the paper 410 and conveys it at a position facing the liquid ejection head 404. The transport belt 412 is an endless belt and is stretched between the transport roller 413 and the tension roller 414. The adsorption can be performed by electrostatic adsorption or air suction.

  The transport belt 412 rotates in the sub-scanning direction when the transport roller 413 is rotationally driven by the sub-scanning motor 416 via the timing belt 417 and the timing pulley 418.

  Further, on one side of the carriage 403 in the main scanning direction, a maintenance / recovery mechanism 420 that performs maintenance / recovery of the liquid ejection head 404 is disposed on the side of the transport belt 412.

  The maintenance / recovery mechanism 420 includes, for example, a cap member 421 for capping the nozzle surface (surface on which the nozzle 411 is formed) of the liquid ejection head 404, a wiper member 422 for wiping the nozzle surface, and the like.

  The main scanning movement mechanism 493, the supply mechanism 494, the maintenance / recovery mechanism 420, and the transport mechanism 495 are attached to a housing including the side plates 491A and 491B and the back plate 491C.

  In this apparatus configured as described above, the paper 410 is fed and sucked onto the transport belt 412, and the paper 410 is transported in the sub-scanning direction by the circular movement of the transport belt 412.

  Therefore, the liquid ejection head 404 is driven in accordance with the image signal while moving the carriage 403 in the main scanning direction, thereby ejecting liquid onto the stopped paper 410 to form an image.

  Thus, since this apparatus includes the liquid ejection head according to the present invention, a high-quality image can be stably formed.

  Next, another example of the liquid discharge unit will be described with reference to FIG. FIG. 8 is an explanatory plan view of the main part of the unit.

  The liquid discharge unit includes a casing portion composed of side plates 491A and 491B and a back plate 491C, a main scanning moving mechanism 493, a carriage 403, and a liquid among the members constituting the liquid discharge device. The discharge head 404 is configured.

  Note that a liquid discharge unit in which at least one of the above-described maintenance and recovery mechanism 420 and the supply mechanism 494 is further attached to, for example, the side plate 491B of the liquid discharge unit may be configured.

  Next, still another example of the liquid discharge unit will be described with reference to FIG. FIG. 9 is an explanatory front view of the unit.

  This liquid discharge unit includes a liquid discharge head 404 to which a flow path component 444 is attached, and a tube 456 connected to the flow path component 444.

  The flow path component 444 is disposed inside the cover 442. A head tank 441 may be included instead of the flow path component 444. In addition, a connector 443 that is electrically connected to the liquid ejection head 404 is provided above the flow path component 444.

  In the present application, the “apparatus for discharging liquid” is an apparatus that includes a liquid discharge head or a liquid discharge unit and drives the liquid discharge head to discharge liquid. The apparatus for ejecting liquid includes not only an apparatus capable of ejecting liquid to an object to which liquid can adhere, but also an apparatus for ejecting liquid toward the air or liquid.

  This “apparatus for discharging liquid” may include means for feeding, transporting, and discharging a liquid to which liquid can adhere, as well as a pre-processing apparatus and a post-processing apparatus.

  For example, as a “liquid ejecting device”, an image forming device that forms an image on paper by ejecting ink, a powder is formed in layers to form a three-dimensional model (three-dimensional model) There is a three-dimensional modeling apparatus (three-dimensional modeling apparatus) that discharges a modeling liquid onto the powder layer.

  Further, the “apparatus for ejecting liquid” is not limited to an apparatus in which significant images such as characters and figures are visualized by the ejected liquid. For example, what forms a pattern etc. which does not have a meaning in itself, and what forms a three-dimensional image are also included.

  The above-mentioned “applicable liquid” means that the liquid can be attached at least temporarily and adheres and adheres, or adheres and penetrates. Specific examples include recording media such as paper, recording paper, recording paper, film, and cloth, electronic parts such as electronic substrates and piezoelectric elements, powder layers (powder layers), organ models, and test cells. Yes, unless specifically limited, includes everything that the liquid adheres to.

  The material of the above-mentioned “applicable liquid” is temporary liquid such as paper, thread, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, building materials such as wallpaper and flooring, textiles for clothing, etc. However, it only needs to be attached.

  In addition, the “device for ejecting liquid” includes a device in which the liquid ejection head and the device to which the liquid can adhere move relatively, but is not limited thereto. Specific examples include a serial type apparatus that moves the liquid discharge head, a line type apparatus that does not move the liquid discharge head, and the like.

  In addition to the “device for discharging liquid”, a processing liquid coating apparatus for discharging a processing liquid onto a sheet for applying a processing liquid to the surface of the sheet for the purpose of modifying the surface of the sheet, or a raw material There is an injection granulator for granulating raw material fine particles by spraying a composition liquid dispersed in a solution through a nozzle.

  In addition, for example, the present invention can be applied to applications such as coating of a protective layer on the surface of a photosensitive drum and coating of a charging roller dielectric in an electrophotographic system.

  A “liquid ejection unit” is a unit in which functional parts and mechanisms are integrated with a liquid ejection head, and is an assembly of parts related to liquid ejection. For example, the “liquid discharge unit” includes a combination of at least one of a head tank, a carriage, a supply mechanism, a maintenance / recovery mechanism, and a main scanning movement mechanism with a liquid discharge head.

  Here, the term “integrated” refers to, for example, a liquid discharge head, a functional component, and a mechanism that are fixed to each other by fastening, adhesion, engagement, etc., and one that is held movably with respect to the other. Including. Further, the liquid discharge head, the functional component, and the mechanism may be configured to be detachable from each other.

  For example, there is a liquid discharge unit in which a liquid discharge head and a head tank are integrated, such as the liquid discharge unit 440 shown in FIG. Also, there are some in which the liquid discharge head and the head tank are integrated by being connected to each other by a tube or the like. Here, a unit including a filter may be added between the head tank and the liquid discharge head of these liquid discharge units.

  In addition, there is a liquid discharge unit in which a liquid discharge head and a carriage are integrated.

  In addition, there is a liquid discharge unit in which the liquid discharge head and the scanning movement mechanism are integrated by holding the liquid discharge head movably on a guide member that constitutes a part of the scanning movement mechanism. As shown in FIG. 8, there is a liquid discharge unit in which a liquid discharge head, a carriage, and a main scanning movement mechanism are integrated.

  Also, there is a liquid discharge unit in which a cap member that is a part of the maintenance / recovery mechanism is fixed to a carriage to which the liquid discharge head is attached, and the liquid discharge head, the carriage, and the maintenance / recovery mechanism are integrated. .

  In addition, as shown in FIG. 9, there is a liquid discharge unit in which a tube is connected to a liquid discharge head to which a head tank or a flow path component is attached, and the liquid discharge head and a supply mechanism are integrated. .

  The main scanning movement mechanism includes a guide member alone. The supply mechanism includes a single tube and a single loading unit.

  The “liquid discharge head” is not limited to the pressure generating means to be used. For example, in addition to the piezoelectric actuator as described in the above embodiment (a multilayer piezoelectric element may be used), a thermal actuator using an electrothermal conversion element such as a heating resistor, a diaphragm and a counter electrode are included. An electrostatic actuator or the like may be used.

  In addition, the terms “image formation”, “recording”, “printing”, “printing”, “printing”, “modeling” and the like in the terms of the present application are all synonymous.

  FIG. 10 is a diagram for schematically explaining the circulation mechanism in the apparatus for ejecting liquid. Although an example in which an ink jet head is used as the liquid discharge head will be described here, the present invention is not limited to this.

  If the discharge liquid discharged from the inkjet head is allowed to stand without stirring, particles such as alumina fine particles contained in the ink are precipitated. In this embodiment, a stirrer 76 is installed at the bottom of the tank, and stirring is performed in the tank. The child 75 is rotated to constantly agitate the discharged liquid. In the circulation configuration, a differential pressure is provided in the liquid feeding tank 73 and the liquid receiving tank 74, and the liquid is circulated by the differential pressure. In order to provide the differential pressure, the pressure is measured by the pressure sensor 77 and adjusted by the suction pump 72 so as to be a predetermined pressure.

  The circulation path is such that the discharge liquid circulates in the order of the liquid feeding tank 73, the inkjet head 70, and the liquid receiving tank 74, and the arrows in the figure indicate the direction of circulation. In this embodiment, the liquid feeding from the liquid receiving tank 74 to the liquid feeding tank 73 is performed using the diaphragm pump 71.

  In this way, the discharge liquid circulates between the liquid feeding tank 73, the inkjet head 70, and the liquid receiving tank 74. Further, the liquid feeding tank 73 and the liquid receiving tank 74 are sucked with air by a tube pump to apply a negative pressure, and the discharge in the inkjet head 70 is prevented so that the discharged liquid does not ooze out from the nozzle holes in the inkjet head 70. The air suction pressure is adjusted so that an appropriate negative pressure is applied to the liquid.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.

Example 1
<Device for discharging liquid>
As a device for discharging the liquid, the one having the configuration shown in FIGS. 6 and 7 was used. In this embodiment, an ink jet apparatus is used.

<Discharged liquid>
The following materials were used as the discharge liquid.
・ Polycarbonate resin ・ Alumina fine particles (volume average particle size: 300 nm) as high hardness fine particles
・ Tetrahydrofuran (THF) and cyclohexanone (anone) as solvent

<Liquid circulation mechanism>
The liquid circulation mechanism shown in FIG. 10 was used. In this embodiment, a stirrer 76 is installed at the bottom of the tank, and the stirring bar 75 is rotated in the tank to constantly agitate the discharged liquid. Further, the discharge liquid is circulated in the order of the liquid feeding tank 73, the ink jet head 70, and the liquid receiving tank 74.

<Capping member>
The capping member of this example was configured as shown in FIG. As the capping member of this example, a sponge block made of polyvinyl alcohol (PVA) was used. Further, the capping member has a porous and liquid-absorbing configuration, and has a size that can sufficiently cover the nozzle surface. The average mesh diameter of the cap member used was 80 μm.

  When the ink jet head is separated from the capping member, an appropriate amount of solvent (tetrahydrofuran and cyclohexanone) is dropped, the squeezing block is pressed against the capping member, and the discharge liquid immersed in the capping member is squeezed out together with the solvent. This squeezing operation is performed periodically. In this embodiment, the squeezing operation is performed every time the inkjet head is separated from the capping member.

In this embodiment, a metal block is used as the aperture block.
The capping member was installed on a fixed base having a mesh bottom, and the discharged liquid and the solvent squeezed by the squeezing operation were discharged from the liquid discharge hole.

At the time of capping, an appropriate amount of solvent was dropped onto the capping member, and then the nozzle surface of the inkjet head was pressed against the capping member to perform capping.
After capping, when the ink jet head was separated from the cap, the discharged liquid was slightly exuded from the head surface.

<Wiping member>
The wiping member of the present embodiment has a configuration shown in FIGS.
As the wiping member, a polyvinyl alcohol (PVA) sponge roller (Aion Cygnus roller) was used. The average mesh diameter of the wiping member was 80 μm.
The roller-like wiping member was connected to a motor for rotating or fixing, and the lower part of the roller-like wiping member was installed so as to be immersed in a solvent pool filled with solvents (tetrahydrofuran and cyclohexanone).

  Moreover, it installed so that it might press on a roller-shaped wiping member, using a metal roller as a squeezing roller. The squeezing roller is rotated by the rotation of the roller-shaped wiping member, and by rotating the wiping member by rotating the motor, the portion of the wiping member soaked in the solvent is pressed against the squeezing roller. The solvent was squeezed out. As a result, the amount of the solvent held by the wiping member was set within a desired range.

  At the time of wiping, with the wiping member fixed so as not to rotate, the nozzle surface of the inkjet head was pressed against the wiping member, and wiping was performed by moving the nozzle surface in parallel with the pressing surface.

(Example 2)
In Example 1, the entire apparatus for discharging liquid, the discharge liquid, the liquid circulation mechanism, and the capping member were the same as in Example 1, and the wiping member was changed to a fluororesin sponge roller (Aion's Floras roller).

(Example 3)
In Example 1, the entire apparatus for discharging liquid, the discharge liquid, the liquid circulation mechanism, and the capping member were the same as in Example 1, and the wiping member was changed as follows.

  The wiping member of this example was configured as shown in FIGS. As a wiping member, a sponge block made of polyvinyl alcohol (PVA) (Belle Eater made by Aion Co., Ltd.) was used. The wiping member of the present embodiment is a sponge material having liquid absorption. The average mesh diameter of the wiping member was 80 μm.

  As shown in FIG. 4, the block-like wiping member was installed on a fixed base having a mesh-like bottom. Before wiping, a solvent (tetrahydrofuran and cyclohexanone) is dropped onto the wiping member, and the discharge liquid soaked by the following squeezing mechanism is squeezed out together with the solvent. As a result, excess solvent was squeezed out so that the wiping member retained an appropriate amount of solvent.

  In addition, a metal block is used as a throttle block and pressed against a block-shaped wiping member to squeeze out excess discharge liquid. As shown in FIG. 5, at the time of wiping, the wiping member in the above state was pressed against the nozzle surface of the inkjet head, and the wipe was performed by moving the wiping member parallel to the head surface while pressing.

(Comparative Example 1)
In Example 1, the entire apparatus for discharging liquid, the discharged liquid and the liquid circulation mechanism were the same as in Example 1, and the capping member and wiping member were changed as follows.
The configuration of the capping member in Comparative Example 1 is shown in FIG. In the cap method shown in FIG. 11A, the nozzle surface 94 of the inkjet head 80 is sealed with a fluororesin-based capping member 82. The capping member in Comparative Example 1 is configured not to hold the solvent of the discharged liquid. While the discharge was stopped, the capping member was brought into close contact with the outside air so that the nozzle hole and the nozzle periphery were not dried.

FIG. 12 is a schematic diagram for explaining the purge, wiping, and discharge operations in the first comparative example. As shown in FIG. 12A, after the ink jet head 80 is separated from the capping member 82 for discharging, the ink jet head 82 moves from the capping member to the liquid receiving portion 88 and enters the liquid chamber in the ink jet head 80. About a few cc of the discharge liquid 87 is discharged from the nozzle under a positive pressure. The discharged discharge liquid 87 is received by the liquid receiving portion 88 and then discarded. Thus, in the comparative example 1, the purge operation is performed to discharge the thickened discharge liquid and bubbles in the nozzle holes. The flow of the discharge liquid is schematically indicated by arrows.
At this time, as shown in FIG. 12 (b), dripping 86 adheres to the nozzle surface of the inkjet head 80 by purging. For this reason, in Comparative Example 1, a fluororesin blade is used as the wiping member 91, and the blade surface is wiped by moving the blade as shown in FIG. Note that the solvent of the discharged liquid is not supplied to the wiping member 91 in Comparative Example 1. Thereafter, ejection is performed as shown in FIG.

(Comparative Example 2)
Comparative Example 1 was the same as Comparative Example 1 except that the blade wiping member was changed to a roller wiping member. That is, the wiping configuration shown in FIG. 12C is the wiping configuration shown in FIG.
In Comparative Example 2, a fluororesin sponge roller (wiping member 92) was used. Further, the roller material is a porous material having a liquid-absorbing property, but the solvent of the discharged liquid is not supplied to the wiping member.
As shown in FIG. 13, the nozzle surface is wiped by rotating the roller. Thereafter, ejection is performed as shown in FIG.

(Evaluation)
FIG. 14 shows the result of observing the discharge state of the discharge liquid by repeating the continuous discharge for 40 seconds in the devices of the above-described examples and comparative examples. FIG. 14 is a photograph of the state of the nozzle surface 94 immediately after discharge and over time and the discharge state of the discharge liquid 87.
In Examples 1 to 3, even when repeated ejection is performed 500 times, no liquid dripping occurs on the nozzle surface, and no liquid ejection or non-abnormal ejection is observed, and a good ejection state is obtained. .
In Comparative Example 1, dripping started to occur on the nozzle surface immediately after the first discharge, the number of non-discharge nozzles gradually increased, and all nozzles were down in about 20 seconds. The same applies to the second and subsequent discharges, and continuous discharge for 40 seconds could not be performed.
In Comparative Example 2, a good discharge state was obtained up to about 10 times from the start, but liquid dripping gradually started from around 10 times and a non-discharge nozzle started to appear, and after 15 times all About 30% of the nozzles were discharged in a down state.

Example 4
In Example 1, the same evaluation as in Example 1 was performed except that the block-shaped capping member was changed from polyvinyl alcohol to fluororesin. Even if the discharge is repeated 500 times in the same manner as in Examples 1 to 3, no liquid dripping occurs on the nozzle surface, and no liquid discharge or abnormal discharge is observed, and a good discharge state is obtained. Yes.

(Comparative Example 3)
Comparative Example 1 was the same as Comparative Example 1 except that the capping member was changed from that shown in FIG. 11 (a) to that shown in FIG. 11 (b).
FIG. 11B shows a system in which the nozzle surface of the head is sealed with a fluororubber sealant. While discharging was stopped, the nozzle hole and the nozzle periphery were not touched so that the outside air was not touched.
When the same evaluation as in the other examples and comparative examples was performed, dripping occurred immediately after discharge as in Comparative Example 1, and dripping became more severe as discharging continued.

(Comparative Example 4)
Comparative Example 1 was the same as Comparative Example 1 except that the capping member was changed from that shown in FIG. 11 (a) to that shown in FIG. 11 (c).
FIG. 11C shows a system in which the nozzle surface of the head is sealed with a fluororubber-based sealing material as in FIG. 11B, but the shape of the capping member and the position of the sealing material are different.
When the same evaluation as in the other examples and comparative examples was performed, dripping occurred immediately after discharge as in Comparative Example 1, and dripping became more severe as discharging continued.

32 Capping member 34 Throttle block 36 Liquid discharge hole 37 Punch hole 38 Fixing base 42 Wiping member 44 Squeezing roller 46 Liquid discharge hole 48 Solvent pool 52 Wiping member 54 Throttle block 56 Liquid discharge hole 57 Mesh 58 Fixing base 59 Liquid pool 60 Liquid discharge Head 62 Rotation or fixing motor 80 Inkjet head 82, 83 Capping member 84 Seal 86 Liquid dripping 87 Liquid discharge 89 Liquid tank 91, 92 Wiping member 94 Nozzle surface 401 Guide member 403 Carriage 404 Liquid discharge head 405 Main scanning motor 406 Drive pulley 407 Driven pulley 408 Timing belt 410 Paper 411 Nozzle 412 Conveying belt 413 Conveying roller 414 Tension roller 416 Sub-scanning motor 417 Timing belt 4 8 Timing pulley 420 Maintenance / recovery mechanism 421 Cap member 422 Wiper member 440 Liquid discharge unit 441 Head tank 442 Cover 443 Connector 444 Flow path component 450 Liquid cartridge 451 Cartridge holder 452 Liquid supply unit 456 Tube 491A, 491B Side plate 491C Back plate 493 Main scan Moving mechanism 494 Supply mechanism 495 Transport mechanism

JP 2004-142450 A JP 2005-111808 A Japanese Patent No. 4858486 JP 2002-273285 A Japanese Patent No. 4485709

Claims (7)

An apparatus for discharging a liquid comprising a liquid discharge head for discharging a liquid containing a solvent from a nozzle surface,
A capping member that caps the nozzle surface of the liquid ejection head;
A wiping member for wiping the nozzle surface of the liquid discharge head,
The capping member can hold the solvent inside and / or on the surface, and caps the nozzle surface while holding the solvent,
The wiping member is capable of holding the solvent inside and / or on the surface thereof, and wipes the nozzle surface while holding the solvent.   The apparatus for discharging a liquid according to claim 1, wherein the solvent held by the capping member and the wiping member is the same component as the solvent contained in the liquid.   The apparatus for ejecting liquid according to claim 1, further comprising a holding amount adjusting unit that adjusts a holding amount of the solvent held by the capping member or the wiping member. The holding amount adjusting unit includes a solvent supply unit that supplies the solvent to the capping member or the wiping member;
The apparatus for ejecting liquid according to claim 3, further comprising: a pressing portion that presses the capping member or the wiping member.   The apparatus for discharging a liquid according to claim 4, wherein the pressing portion has a roller shape or a block shape.   The apparatus for discharging a liquid according to claim 1, wherein the wiping member has a roller shape or a block shape. A liquid discharge method for discharging by a liquid discharge head for discharging a liquid containing a solvent from a nozzle surface,
A discharge step of discharging the liquid;
A capping step of capping the nozzle surface of the liquid ejection head with a capping member;
A wiping step of wiping the nozzle surface of the liquid discharge head with a wiping member,
The capping member can hold the solvent inside and / or on the surface, and caps the nozzle surface while holding the solvent,
The liquid wiping method, wherein the wiping member can hold the solvent inside and / or on the surface, and wipes the nozzle surface while holding the solvent.