JP2011224780A - Liquid ejector and liquid ejection head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ejector which can suppress evaporation of a solvent in the liquid from a nozzle effectively, and to provide a liquid ejection head.SOLUTION: The liquid ejector includes a liquid ejection head having a nozzle opening face where nozzles 37 are opened, and ejects liquid droplets from the nozzles by filling a pressure chamber 35 communicating with the nozzles 37 with liquid and imparting pressure variation to the liquid in the pressure chamber 35; is further provided with a means for supplying moistening solution to the nozzle opening face side. A moistening hole 45 to which the moistening solution is supplied from the means for supplying moistening solution is formed at a position deviated from the nozzle opening in the nozzle opening face, and the moistening hole 45 holds the moistening solution by surface tension.

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer, and a liquid ejecting head, and in particular, a liquid ejecting apparatus capable of more effectively suppressing volatilization of a liquid solvent from a nozzle, and The present invention relates to a liquid ejecting head.

  The liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting liquid and ejects liquid from the liquid ejecting head to land on a landing target. As a typical example of this liquid ejecting apparatus, for example, an ink jet recording head (a type of liquid ejecting head; hereinafter simply referred to as a recording head) is provided, and liquid ink is ejected from nozzles of the recording head to perform recording. An image recording apparatus such as an ink jet printer (hereinafter simply referred to as a printer) that records an image, text, or the like by landing on a recording medium (a kind of landing target) such as a printing surface of paper or an optical disk can be given. . In recent years, the ink jet technology of the liquid ejecting apparatus is applied not only to the image recording apparatus but also to various manufacturing apparatuses such as a manufacturing apparatus for a color filter such as a liquid crystal display and an electrode forming apparatus.

  In such a liquid ejecting apparatus, the nozzle is exposed to the atmosphere during the printing operation. For this reason, the liquid solvent component volatilizes through the nozzle. As a result, the viscosity of the liquid increases in the vicinity of the nozzle, which may cause problems such as a decrease in the weight of the ejected ink and a decrease in the flying speed of the ink. Various measures are taken in the liquid ejecting apparatus in order to suppress such problems caused by the thickening of the liquid. For example, taking the above ink jet printer as an example, a cleaning liquid tank and a pump are connected to a cap member that seals the surface of the recording head where the nozzles are opened (hereinafter referred to as a nozzle opening surface), and the cleaning liquid is contained in the cap member. Ink solvent in the vicinity of the nozzles can be supplied and discharged by maintaining the inside of the cap member at a high humidity by holding the cleaning liquid in the cap member after cleaning the nozzles of the recording head during the non-recording operation. The structure which suppresses volatilization of this is proposed (refer patent document 1).

JP 2004-209897 A

  However, in the above-described configuration, the nozzle opening surface is released from the cap member during the recording process (during the ejection process) on the recording medium, and thus it has not been possible to reliably prevent ink thickening.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a liquid ejecting apparatus and a liquid ejecting head that can more effectively suppress the volatilization of a liquid solvent from a nozzle. It is to provide.

The present invention has been proposed in order to achieve the above-described object, and has a nozzle opening surface in which a nozzle is opened, fills a pressure chamber communicating with the nozzle with liquid, and changes the pressure in the liquid in the pressure chamber. A liquid ejecting apparatus including a liquid ejecting head capable of ejecting liquid droplets from the nozzle by applying
A humidifying liquid supply means for supplying the humidifying liquid to the nozzle opening surface side;
A humidifying hole for supplying the humidifying liquid from the humidifying liquid supply means is formed at a position off the nozzle opening on the nozzle opening surface,
The humidifying hole holds the humidifying liquid by surface tension.

According to this configuration, the humidifying hole is formed at a position off the nozzle opening on the nozzle opening surface, and the humidifying hole holds the humidifying liquid by the surface tension, so the humidifying hole held in the humidifying hole is By evaporating the working liquid and humidifying the atmosphere, it becomes possible to maintain the humidity near the nozzle in a higher state. Thereby, the evaporation of the liquid from a nozzle is suppressed and the raise of a liquid viscosity is suppressed. As a result, ejection failure due to thickening of the liquid, that is, malfunction such as the amount of the ejected liquid and the flying speed being significantly reduced from the design target values, or the liquid not being ejected from the nozzle, is prevented. can do.
Further, since the humidifying liquid is held in the humidifying hole on the nozzle opening surface, it is possible to suppress static electricity from being transmitted from the nozzle through the liquid to the pressure generating means, the drive circuit, and the like.
Further, since a large-scale device such as a mechanism for sending the volatilizing liquid for humidification to the nozzle side is unnecessary, it is possible to suppress the increase in size of the device and the cost.

In the above configuration, the liquid jet head includes a nozzle group in which the nozzles are arranged in a plurality of rows.
A plurality of the humidifying holes are formed in the nozzle opening surface,
It is desirable that the humidifying holes are arranged along the nozzle arrangement direction.
According to this configuration, it is possible to humidify the nozzles uniformly with the humidifying liquid held in the humidifying holes.

Moreover, it is desirable that the humidifying liquid supply means arranges a humidifying liquid storage section storing the humidifying liquid above the nozzle opening surface in the gravity direction.
According to this structure, a humidification solution can be supplied to the humidification hole side using gravity.

Further, in the above configuration, a wiping member for wiping the nozzle opening surface of the liquid jet head is provided,
It is desirable that the humidifying holes are arranged so as not to line up with the nozzle in the wiping direction of the wiping member.
According to the said structure, a possibility that a wiping member may be damaged by the humidification hole can be reduced.

Further, in the above configuration, the humidifying liquid supply means includes
It is desirable to employ a configuration having liquid feeding means for supplying the humidifying liquid to the humidifying hole.
According to the above configuration, the humidifying liquid can be supplied to each humidifying hole without unevenness.

Moreover, in the said structure, it is desirable to employ | adopt the structure provided with the moisturizing liquid detection means which detects the moisturizing liquid currently hold | maintained at the said humidification hole.
In this configuration, the humidifying liquid supply means supplies the humidifying liquid to the humidifying hole by driving the liquid feeding means when no moisturizing liquid is detected by the moisturizing liquid detecting means. It is desirable to adopt.
According to the above configuration, the humidifying liquid can be retained in each humidifying hole without excess or deficiency.

In the above configuration, the liquid is ink.
The moisturizing liquid may employ a configuration including one or more volatile components of ink.

Furthermore, it is desirable that a liquid repellent treatment is performed on the nozzle opening surface.
According to this configuration, the humidifying liquid held in the humidifying hole is prevented from leaking to the nozzle opening surface. Thereby, it is possible to prevent the humidifying liquid from dripping from the liquid jet head. Various existing configurations can be adopted as the liquid repellent treatment.

The liquid jet head of the present invention has a nozzle opening surface in which a nozzle is opened, fills a pressure chamber communicating with the nozzle with liquid, and applies pressure fluctuations to the liquid in the pressure chamber. A liquid ejecting head capable of ejecting droplets,
A humidifying liquid supply means for supplying the humidifying liquid to the nozzle opening surface side;
A humidifying hole for supplying the humidifying liquid from the humidifying liquid supply means is formed at a position off the nozzle opening on the nozzle opening surface,
The humidifying hole holds the humidifying liquid by surface tension.

According to this configuration, the humidifying hole is formed at a position off the nozzle opening on the nozzle opening surface, and the humidifying hole holds the humidifying liquid by the surface tension, so the humidifying hole held in the humidifying hole is By evaporating the working liquid and humidifying the atmosphere, it becomes possible to maintain the humidity near the nozzle in a higher state. Thereby, the evaporation of the liquid from a nozzle is suppressed and the raise of a liquid viscosity is suppressed. As a result, ejection failure due to thickening of the liquid, that is, malfunction such as the amount of the ejected liquid and the flying speed being significantly reduced from the design target values, or the liquid not being ejected from the nozzle, is prevented. can do.
Further, since the humidifying liquid is held in the humidifying hole on the nozzle opening surface, it is possible to suppress static electricity from being transmitted from the nozzle through the liquid to the pressure generating means, the drive circuit, and the like.

FIG. 3 is a perspective view illustrating a configuration of a printer. FIG. 3A is a front view of a recording head in the first embodiment, and FIG. FIG. 3 is a plan view of the recording head in the first embodiment. (A) BB sectional drawing (b) CC sectional view (c) DD sectional drawing in FIG. FIG. 3 is a cross-sectional view of a main part of the recording head in the first embodiment. FIG. 7A is a front view of a recording head according to a second embodiment, and FIG. FIG. 6 is a plan view of a recording head in a second embodiment. (A) Front view of recording head in third embodiment (b) FF sectional view (c) Enlarged view of region X. FIG. 10 is a plan view of a recording head according to a third embodiment. It is the GG sectional view taken on the line in FIG. It is the HH sectional view taken on the line in FIG. It is the II sectional view taken on the line in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the following, an ink jet recording apparatus (hereinafter referred to as a printer) will be described as an example of the liquid ejecting apparatus of the invention.

  The printer 1 shown in FIG. 1 has a cartridge mounting portion 2 to which an ink cartridge 5 storing ink (a kind of liquid in the present invention) is attached, and a humidifying liquid tank 17 described later (humidifying liquid in the present invention). A carriage 4 on which the recording head 3 (a kind of liquid ejecting head in the present invention) and a recording head 3 are mounted is provided. The carriage 4 is connected to a timing belt 10 installed between the drive pulley 8 and the idle pulley 9 while being supported by the guide rod 6. The drive pulley 8 is joined to the rotating shaft of the pulse motor 11. The operation of the pulse motor 11 causes the carriage 4 to move in the width direction of the recording paper 7 (recording medium or a kind of landing target), that is, main scanning. It is designed to move in the direction.

  A paper feed roller 12 is disposed below the guide rod 6 in parallel with the guide rod 6. The paper feed roller 12 is configured to be rotated by the driving force from the paper feed motor 13 to convey the recording paper 7 on the platen 14 in the sub-scanning direction.

  A home position serving as a base point for the movement of the recording head 3 is located in an end area outside the recording area in which an image or the like is printed on an ejection target such as recording paper within the movement range of the carriage 4. Is set. On the home position side, a capping mechanism 15 capable of capping (sealing) the nozzle opening surface of the recording head 3 and a wiping mechanism 16 for wiping the nozzle opening surface are disposed adjacent to each other. . The capping mechanism 15 includes a cap member 15 ′ that can seal the nozzle opening surface of the recording head 3, that is, the ejection side surface of the nozzle plate 31, and can move the cap member 15 ′ up and down. It is configured. The cap member 15 'is a substantially rectangular box in plan view, more specifically, a tray-like member having an open upper surface side, and the whole is made of an elastic material such as an elastomer. When the carriage 4 is positioned at the home position, the cap member 15 ′ moves upward to enter a capping state that seals the nozzle opening surface of the recording head 3. In this capping state, the nozzle 37 established on the nozzle opening surface faces the empty space inside the cap member 15 ', and the upper end edge of the cap member 15' and the nozzle opening surface are in close contact with each other. Accordingly, evaporation of the ink solvent from the nozzles of the recording head 3 is suppressed, and an increase in ink viscosity is suppressed. When the recording head 3 records an image or the like on the ejection target, the capping state of the cap member 15 ′ with respect to the nozzle opening surface is released. In addition, the nozzle opening surface in this invention is not restricted to the injection surface of the nozzle plate 31, Other members (for example, flow path) provided in the outer periphery (it is not restricted on the same surface) of the injection surface of the nozzle plate 31 When the substrate 30 or a metal cover is present, the member is also included in the nozzle opening surface. Therefore, the structure which provides the hole 45 for the humidification mentioned later to the said member is also employable.

  A wiping mechanism 16 is provided between the capping mechanism 15 and the recording area (platen 14). The wiping mechanism 16 has a wiper blade 16 '(a kind of wiping member in the present invention). The wiping mechanism 16 advances and retreats to and from a wiping position where the tip of the wiper blade 16 ′ overlaps the movement path of the recording head 3 and a retreat position where the tip of the blade 16 ′ is not in contact with the recording head 3. It is possible. When wiping the nozzle opening surface of the recording head 3, the wiper blade 16 ′ is moved to the wiping position, and the recording head 3 and the wiper blade 16 ′ are in contact with the tip of the wiper blade 16 ′ in contact with the nozzle opening surface. The wiper blade 16 'wipes the ink and the like adhering to the nozzle opening surface. In the present embodiment, the relative movement direction of the wiper blade 16 ′ with respect to the nozzle opening surface is parallel to the nozzle row 44.

  2 to 5 are diagrams illustrating the configuration of the recording head 3, the ink cartridge 5, and the humidifying liquid tank 17 in the first embodiment. FIG. 2A is a front view of the recording head 3. 2B is a cross-sectional view taken along line AA in FIG. 2A, FIG. 3 is a plan view of the recording head 3, FIG. 4 is a cross-sectional view taken along line BB in FIG. It is CC sectional view, (c) DD sectional view. FIG. 5 is a cross-sectional view of the main part of the recording head 3 and shows only the configuration corresponding to one of the two nozzle rows 44. 2 to 4, the carriage 4 is not shown. Further, in FIG. 5, the configuration corresponding to the other nozzle row 44 is omitted because it is symmetrical in the left-right direction with that shown in FIG.

  The ink cartridge 5 and the humidifying liquid tank 17 are detachably attached to the carriage 4 so as to be positioned on the upper surface side of the recording head 3. In other words, the ink cartridge 5 and the humidifying liquid tank 17 are arranged above the nozzle opening surface (surface on the ejection side of the nozzle plate 31) of the recording head 3 in the gravity direction. Thereby, ink or a humidified solution can be supplied to the recording head 3 side using gravity. The ink cartridge 5 is a member formed in the shape of a hollow box, and ink is accommodated in an ink storage space 5 ′ partitioned therein. In the present embodiment, two ink cartridges 5 can be attached to the recording head 3. An ink introduction needle 22 provided on the upper surface (the surface opposite to the nozzle opening surface) of the recording head 3 is inserted into the ink cartridge 5, and ink is stored through the ink introduction needle 22. Ink stored in the void 5 ′ is introduced into an ink flow path (a type of liquid flow path) inside the recording head 3. The humidifying liquid tank 17 is a member formed in the shape of a hollow box like the ink cartridge 5, and the nozzle opening surface of the recording head 3 is located in the humidifying liquid storage space 17 ′ partitioned inside the ink cartridge 5. Contains a humidifying liquid for humidifying. The humidifying liquid storage space 17 ′ communicates with the humidifying liquid supply path 27 formed in the case 23 of the recording head 3 through the humidifying liquid supply tube 18. The humidifying liquid is a liquid for increasing the humidity of the nozzle opening surface by being held in a humidifying hole 45 described later. As the humidifying liquid, pure water, an ink solvent, or the like can be used. From the viewpoint of humidifying the nozzle opening surface, it is desirable that the humidifying liquid contains one or more volatile components of the ink. As the volatile component, petroleum or alcohol can be employed. In this embodiment, the ink cartridge 5 and the humidifying liquid tank 17 are mounted on the carriage 4. However, the present invention is not limited to this. For example, the ink cartridge 5 and the humidifying liquid tank 17 are arranged on the main body side of the printer 1 and the ink and the humidifying liquid stored in the ink cartridge 5 and the humidifying liquid tank 17 are supplied to the recording head 3 side through a supply tube or the like. It is also possible to adopt.

  The humidifying liquid supply path 27 is a flow path formed in the recording head 3 independently at a position outside the ink flow path. The humidifying liquid supply path 27 in the present embodiment includes a lateral flow path 27a parallel to the nozzle opening surface (nozzle plate 31) and a vertical flow path 27b perpendicular to the nozzle opening surface. The horizontal flow path 27a is a flow path formed so as to connect the upper ends of the vertical flow paths 27b. Specifically, as shown in FIG. 2 (b), the lateral flow path 27a has two flow streams formed in both ends of the case 23 in the nozzle row direction and extending in the direction orthogonal to the nozzle row direction. Path and three flow paths that extend in parallel along the nozzle row direction, and communicate with each other at a position that deviates (avoids) from a position corresponding to a series of ink flow paths, which will be described later, and a position that surrounds the periphery. And is located on the upper surface side opposite to the nozzle opening surface in the height direction of the case 23. Then, the humidifying liquid supply tube 18 is connected to the lateral flow path 27a in a liquid-tight state via an introduction path 27a '. On the other hand, the vertical flow path 27b is a flow path whose upper end communicates with the horizontal flow path 27a and whose lower end communicates with a humidification hole 45 (described later) on the nozzle opening surface, as shown in FIG. Along the direction, it is formed across the constituent members (the diaphragm 32 and the flow path substrate 30) of the recording head 3 including the case 23. Therefore, the humidifying liquid that has flowed from the humidifying liquid tank 17 into the humidifying liquid supply path 27 through the humidifying liquid supply tube 18 passes through the horizontal flow path 27a and the vertical flow path 27b, and is thus provided on the nozzle opening surface. 45 is supplied. Therefore, the humidifying liquid tank 17 and the humidifying liquid supply path 27 correspond to a kind of humidifying liquid supply means in the present invention.

Next, a configuration for ejecting ink of the recording head 3 will be described.
As shown in FIG. 5, the recording head 3 includes a case 23, a vibrator unit 24 housed in the case 23, a flow path unit 25 joined to the bottom surface (tip surface) of the case 23, and the like. Yes. The case 23 is made of, for example, an epoxy resin, and a housing empty portion 26 for housing the vibrator unit 24 is formed therein. The vibrator unit 24 includes a piezoelectric vibrator 20 that functions as a kind of pressure generating means, a fixed plate 28 to which the piezoelectric vibrator 20 is joined, and a flexible cable 29 for supplying a drive signal and the like to the piezoelectric vibrator 20. And. The piezoelectric vibrator 20 is a laminated type produced by cutting a piezoelectric plate in which piezoelectric layers and electrode layers are alternately laminated into a comb-like shape, and can be expanded and contracted in a direction perpendicular to the lamination direction (electric field direction). This is a piezoelectric vibrator in a longitudinal vibration mode (field transverse effect type).

  The flow path unit 25 is configured by joining a nozzle plate 31 to one surface of the flow path substrate 30 and a diaphragm 32 to the other surface of the flow path substrate 30. The flow path unit 25 is provided with a reservoir 33 (common liquid chamber), an ink supply port 34, a pressure chamber 35, a nozzle communication port 36, and a nozzle 37. A series of ink flow paths from the ink supply port 34 to the nozzle 37 through the pressure chamber 35 and the nozzle communication port 36 are formed corresponding to each nozzle 37.

  The nozzle plate 31 is a member in which a plurality of nozzles 37 are formed in rows at a pitch (for example, 180 dpi) corresponding to the dot formation density. In the present embodiment, the nozzle plate 31 is made of, for example, stainless steel. The nozzle plate 31 may be made of a silicon single crystal substrate. This nozzle plate 31 is characterized in that it has a humidifying hole 45 on the surface (nozzle opening surface) on the ink ejection side for holding the humidifying liquid. Details of this point will be described later.

  The diaphragm 32 has a double structure in which an elastic film 39 is laminated on the surface of a support plate 38. In this embodiment, the vibration plate 32 is manufactured using a composite plate material in which a stainless steel plate, which is a kind of metal plate, is used as the support plate 38 and a resin film is laminated on the surface of the support plate 38 as an elastic film 39. The diaphragm 32 is provided with a diaphragm portion 40 that changes the volume of the pressure chamber 35. The diaphragm 32 is provided with a compliance portion 41 that seals a part of the reservoir 33.

  The diaphragm 40 is produced by partially removing the support plate 38 by etching or the like. That is, the diaphragm portion 40 includes an island portion 42 to which the tip end surface of the free end portion of the piezoelectric vibrator 20 is joined, and a thin elastic portion 43 surrounding the island portion 42. The compliance part 41 is produced by removing the support plate 38 in the region facing the opening surface of the reservoir 33 by etching or the like in the same manner as the diaphragm part 40, and the pressure fluctuation of the liquid stored in the reservoir 33 is reduced. Functions as a damper to absorb.

  Since the tip surface of the piezoelectric vibrator 20 is joined to the island portion 42, the volume of the pressure chamber 35 can be changed by expanding and contracting the free end of the piezoelectric vibrator 20. A pressure fluctuation occurs in the ink in the pressure chamber 35 along with the volume fluctuation. The recording head 3 ejects ink droplets from the nozzles 37 using this pressure fluctuation. Although not shown, the recording head 3 is attached with a metal head cover that covers the peripheral edge of the nozzle opening surface. The head cover is connected to a ground line, and is electrically connected to the nozzle plate 31 so that, for example, static electricity generated from the recording paper 7 or the like is transmitted through the nozzle plate, thereby damaging the driving IC or the like. And malfunctions such as malfunctions are prevented.

As shown in FIG. 3, the nozzle plate 31 is provided with a nozzle row 44 (nozzle group) in which a plurality of nozzles 37 are arranged at equal intervals, and one nozzle row 44 has, for example, 180 pieces. Nozzle 37. In this embodiment, two nozzle rows 44 are formed side by side in the moving direction of the recording head 3. A plurality of humidifying positions are located on the ejection side surface (nozzle opening surface) of the nozzle plate 31 at a position deviated (avoided) from the opening of the nozzle 37 and deviated from the position corresponding to the series of ink flow paths. A hole 45 is formed. Further, as shown in FIG. 5, each of the humidifying holes 45 is a hole set to have an opening diameter enough to hold the above-described humidifying liquid by surface tension, and the lower end of the vertical flow path 27b is Communicate. As shown in FIG. 3, in the present embodiment, a plurality of humidifying holes 45 are arranged at the same pitch as the nozzle pitch, and three first humidifying hole rows 45a extending in parallel along the nozzle row direction. And two second humidifying hole rows 45b extending in the direction perpendicular to the humidifying hole row on both sides in the nozzle row direction and intersecting each first humidifying hole row 45a. . Further, the vertical flow path 27b corresponding to each humidification hole 45 communicates with the horizontal flow path 27a at the upper end, and the humidification liquid from the humidification liquid tank 17 is transferred to the horizontal flow path 27a and each vertical flow path 27b. And are respectively supplied to the corresponding humidifying holes 45 on the nozzle opening surface.
The number and positions of the humidifying holes 45 formed on the nozzle opening surface are not limited to those exemplified in the present embodiment, but at least along the direction of the nozzle row 44 at a position closer to the nozzle row. By forming the humidifying hole row 45a, the nozzles 37 can be uniformly humidified by the humidifying liquid held in the humidifying holes 45. Further, the degree of humidification can be adjusted by changing the number of humidification holes 45 formed. For example, the formation pitch of the humidifying hole row formed along the nozzle row corresponding to the ink that tends to volatilize or has a high viscosity is set to be smaller and corresponds to the ink that is less likely to volatilize or has a lower viscosity. With respect to the formation pitch of the humidifying hole rows formed along the nozzle rows, it is possible to adopt a configuration in which the pitch is set larger.
Then, it is desirable that a liquid repellent treatment is performed on the nozzle opening surface of the nozzle plate 31 other than the nozzle 37 and the humidifying hole 45 by forming a liquid repellent coating layer. Thereby, it becomes difficult for ink to adhere to the nozzle opening surface, and the wiping performance of the nozzle opening surface by wiping of the wiping mechanism 16 is improved. In addition, the humidifying liquid held in the humidifying hole 45 is prevented from leaking to the outside (nozzle opening surface) of the humidifying hole 45. Thereby, it is possible to prevent the humidifying liquid from dripping from the recording head 3. An existing configuration can be adopted as the liquid repellent treatment. For example, eutectoid plating is used as the liquid repellent coating layer. Specifically, after immersing the nozzle plate to which the electrode is connected in an electrolyte solution containing metal ions such as nickel ions and particles of a liquid repellent polymer resin such as a fluororesin, and plating the surface thereof The liquid-repellent coating layer can be obtained by applying a load and overheating while suppressing warpage.

In the recording head 3 configured as described above, the humidifying hole 45 formed in the nozzle opening surface holds the humidifying liquid by surface tension, so that the nozzle opening surface can be released from capping by the capping mechanism 15. The humidification liquid held in the humidification hole 45 evaporates and is humidified in the atmosphere, so that the humidity near the nozzle 37 can be maintained at a higher level. Thereby, evaporation of the ink solvent from the nozzle 37 is suppressed, and an increase in ink viscosity is suppressed. As a result, ejection failure due to ink thickening, that is, the amount of ejected ink and the flying speed are significantly reduced from the design target values, or the ink is not ejected from the nozzle 37, etc. Can be prevented.
In addition, since a large-scale device such as a mechanism for sending the volatilized humidifying liquid to the nozzle side is unnecessary, the size of the device can be suppressed and the cost can be suppressed.
Furthermore, even in a recording head having a plurality of nozzle rows, by providing a plurality of humidifying holes 45 (humidifying hole rows 45a) along the nozzle rows, the nozzles 37 can be uniformly humidified without unevenness. it can.
Further, since the humidity in the vicinity of the nozzle 37 is maintained at a higher level, for example, static electricity generated from the recording paper 7 or the like is transmitted from the nozzle 37 through the ink to the piezoelectric vibrator 20 or the drive circuit and is damaged. It is suppressed. In particular, when a highly insulating liquid repellent film or the like is formed on the nozzle opening surface, static electricity can be released to the humidifying liquid side held in the humidifying hole 45, and the problem due to static electricity is more effective. Can be prevented.

Next, a second embodiment of the present invention will be described.
6 to 7 are diagrams for explaining the configuration of the present embodiment. FIG. 6A is a front view of the recording head 3, and FIG. 6B is a cross-sectional view taken along line EE in FIG. FIG. 7 is a plan view of the recording head 3. In the present embodiment, with respect to the plurality of humidifying holes 45, only the three first humidifying hole rows 45a are formed, and the second humidifying hole row 45b is not formed. It is different from the form. That is, the plurality of humidifying holes 45 in the present embodiment are along the wiping direction of the wiper blade 16 ′ during wiping (the relative movement direction of the nozzle opening surface and the wiper blade 16 ′, indicated by arrows in FIG. 7). It consists only of the extending humidifying hole row 45a. In other words, the humidifying holes 45 are arranged so as not to line up with the nozzles 37 in the wiping direction. As a result, when the wiper blade 16 'is wiped off, the number of contact points between the humidifying hole 45 and the wiper blade 16' can be reduced, and damage to the wiper blade 16 'can be suppressed. Further, it is possible to suppress an increase in operation sound during wiping. Further, since the humidifying hole 45 and the nozzle 37 are not aligned on the same line in the wiping direction, the humidifying liquid held in the humidifying hole 45 is mixed with the ink in the nozzle 37 when wiping with the wiper blade 16 ′. Can be prevented. In addition, as shown in FIG. 6, the horizontal flow path 27a with which the vertical flow path 27b corresponding to each humidification hole 45 communicates has three flow paths (nozzles corresponding to the first humidification hole row 45a in the case 23. A flow path extending in parallel to the row 44) and one flow path orthogonal to the flow path at one end (humidification liquid supply tube 18 side) end. As in the first embodiment, the humidifying liquid from the humidifying liquid tank 17 is supplied to the corresponding humidifying holes 45 on the nozzle opening surface through the horizontal flow path 27a and the vertical flow paths 27b. Is done. Since other configurations are the same as those in the first embodiment, description thereof is omitted.

Next, a third embodiment of the present invention will be described.
8 to 12 are diagrams for explaining the configuration of the present embodiment. FIG. 8A is a front view of the recording head 3, and FIG. 8B is a sectional view taken along line FF in FIG. FIG. 8C is an enlarged view of the region X in FIG. 9 is a plan view of the recording head 3, FIG. 10 is a sectional view taken along line GG in FIG. 9, FIG. 11 is a sectional view taken along line HH in FIG. 9, and FIG. It is. In the present embodiment, one of the configurations for ejecting ink (the configuration of the flow path from the reservoir 33 to the pressure chamber 35 and the piezoelectric vibrator 20 and the like) is used as a supply pump, and the humidifying liquid is supplied to the humidifying hole. The point which has the liquid feeding means supplied to 45 differs from said each embodiment. More specifically, in the humidifying liquid reservoir 33 ′, the humidifying liquid supply port 34 ′, the humidifying liquid supply pressure chamber 35 ′, and the humidifying liquid supply pressure chamber 35 ′ independent of the ink flow path. A humidifying liquid supply piezoelectric vibrator 20 ′ (a kind of liquid feeding means) is provided for applying pressure fluctuations. The configuration for supplying the humidifying liquid (part of the humidifying liquid supply means in the present invention) is basically the same as the configuration for ejecting ink, but the configuration for supplying the humidifying liquid is used. Then, the nozzle 37 is not provided.

  As shown in FIG. 10, the humidifying liquid tank 17 communicates with an introduction flow path 46 formed in the case 23 of the recording head 3 through the humidification liquid supply tube 18. The humidifying liquid reservoir 33 'is communicated. Therefore, the humidifying liquid that has flowed from the humidifying liquid tank 17 into the introduction flow path 46 through the humidifying liquid supply tube 18 is supplied through the humidifying liquid reservoir 33 ′ and the humidifying liquid supply port 34 ′. To the pressure chamber 35 '. One end of the communication channel 47 opens at the upper part of the pressure chamber 35 ′ for supplying the humidifying liquid on the side opposite to the nozzle opening surface. As shown in FIG. 10, the other end of the communication channel 47 communicates with the lateral channel 27 a of the humidifying liquid supply channel 27. As shown in FIG. 8B, the lateral flow path 27a includes three flow paths extending in parallel to the nozzle row 44 in the case 23, and one side of the flow path (the humidifying liquid supply tube 18 side). ) It is composed of one flow path orthogonal to the end portion and an optical path (described later) orthogonal to the three flow paths inside the other end portion. When the humidifying liquid supply piezoelectric vibrator 20 ′ is driven with the above-described configuration, the volume of the humidifying liquid supply pressure chamber 35 ′ fluctuates, and the humidifying liquid supply pressure chamber 35 varies with the volume fluctuation. Pressure fluctuation occurs in the humidifying liquid filled in the ′. Then, using this pressure variation, the humidifying liquid can be supplied to each humidifying hole 45 from the humidifying liquid supply pressure chamber 35 ′ through the communication channel 47 and the humidifying liquid supply channel 27. Accordingly, the humidifying liquid can be supplied to each humidifying hole 45 without any unevenness. Further, when the humidifying liquid is initially filled in each humidifying hole 45, the filling can be completed in a shorter time.

  It should be noted that a plurality of configurations (liquid feeding means) functioning as a pump for humidifying liquid may be provided, and which of the configurations for ejecting ink is used as a pump for the humidifying liquid. Is also optional. For example, one humidifying liquid supply piezoelectric vibrator 20 ′ is provided for each humidifying hole 45, and a series of flow paths (humidifying liquid supply paths 27, etc.) to each humidifying hole 45 are independent of each other. If it forms in this, the humidification quantity for every humidification hole 45 can be adjusted, and partial humidification is also attained. In this case, it is possible to efficiently humidify by controlling the amount of the humidifying liquid in the humidifying hole 45 located in the vicinity of the nozzle 37 that tends to thicken (for example, the nozzle 37 with a small number of ink ejections). Note that a pump mechanism having another configuration may be used without using the humidifying liquid supply pressure chamber 35 ', the humidifying liquid supply piezoelectric vibrator 20', or the like.

The present embodiment is also characterized in that moisturizing liquid detection means for detecting whether or not the humidifying liquid is held in the humidifying hole 45 is provided.
As shown in FIG. 8B, in the lateral flow path 27a, three flow paths that extend in parallel to the nozzle row 44 on the side opposite to the humidifying liquid supply tube 18, and inside the end of the flow path Thus, an optical path 48 extending in a direction orthogonal to the nozzle row is formed. The optical path 48 is a cylindrical hollow portion through which light can pass and into which the humidifying liquid can flow. And in the flow path located in the center among the three flow paths extending parallel to the nozzle row 44 of the lateral flow path 27a, as shown in FIG. In the cross-section (plan view) pentagonal (home base type) prism 51, three of the sides forming the pentagonal shape are in contact with the inner wall of the channel end, and the remaining two sides are not in contact with the inner wall. Is arranged at a position where it intersects the optical path 48. Here, the prism 51 is made of plastic, glass, quartz glass, or the like, and a prism having a refractive index close to that of the humidifying liquid is selected. For example, when the humidifying liquid is water (refractive index of about 1.33), the prism is preferably formed of quartz glass (refractive index of about 1.45) or the like. Further, the inner wall of the flow path with which the prism 51 abuts is painted black so that light is not reflected. Further, an air hole 52 communicating with the outside is formed above the lateral flow path 27a (on the ink cartridge 5 side) (see FIG. 10). A filter or the like that does not allow liquid to pass through the air holes 52 may be provided. A light emitting element 49 is disposed at one end of the optical path 48 (right end in FIG. 8B), and a light receiving element 50 is disposed at the other end (left end in FIG. 8B). Has been. The light emitting element 49 is composed of, for example, a light emitting diode. The light receiving element 50 is configured by a photodiode or a phototransistor. In the present embodiment, the optical path 48, the light emitting element 49, the light receiving element 50, and the prism 51 function as a moisturizing liquid detecting means in the present invention.

  When the horizontal flow path 27a is not filled with the humidifying liquid and there is no humidifying liquid around the optical path 48 and the prism 51, the light from the light emitting element 49 is filled with the air from the air hole 52. As indicated by Da in FIG. 8C, when entering the prism 51, it is refracted by the difference in refractive index between the prism 51 and air. For this reason, the refracted light hits the inner wall of the flow path and is not received by the light receiving element 50. On the other hand, when the horizontal flow path 27a is sufficiently filled with the humidifying liquid and the optical path 48 and the prism 51 are filled with the humidifying liquid, the prism 51 has a refractive index close to that of the humidifying liquid. As shown by Db in FIG. 8 (c), the light is able to suppress refraction when entering and exiting the prism 51 and is received by the light receiving element 50.

  A detection signal from the light receiving element 50 is output to a control unit (not shown) of the printer 1 main body. Therefore, the control unit can determine whether or not the humidifying liquid is filled in the horizontal flow path 27a based on the detection signal of the light receiving element 50. The control unit functions as a part of the humidifying liquid supply means, and controls the liquid feeding means (humidifying liquid supply piezoelectric vibrator 20 ') based on the detection signal, thereby humidifying the horizontal flow path 27a. The liquid can be held without excess and deficiency, and the humidifying hole 45 can be stably humidified via the lateral flow path 27b. For example, when the moisturizing liquid in the humidifying hole 45 is not detected, the humidifying liquid supplied in the humidifying liquid supply pressure chamber 35 ′ is driven by driving the humidifying liquid supplying piezoelectric vibrator 20 ′. Are supplied to the humidifying holes 45 through the flow paths. Other configurations are the same as those in the second embodiment, and the description thereof is omitted.

  In the above, an ink jet printer which is a kind of liquid ejecting apparatus has been described as an example, but the present invention can also be applied to other liquid ejecting apparatuses. For example, a display manufacturing apparatus for manufacturing a color filter such as a liquid crystal display, an electrode manufacturing apparatus for forming electrodes such as an organic EL (Electro Luminescence) display and FED (surface emitting display), and a chip for manufacturing a biochip (biochemical element) The present invention can also be applied to a manufacturing apparatus and a micropipette that supplies an accurate amount of a very small amount of sample solution. In the display manufacturing apparatus, a solution of each color material of R (Red), G (Green), and B (Blue) is ejected from the color material ejecting head. Moreover, in an electrode manufacturing apparatus, a liquid electrode material is ejected from an electrode material ejection head. In the chip manufacturing apparatus, a bioorganic solution is ejected from a bioorganic ejecting head.

  DESCRIPTION OF SYMBOLS 1 ... Printer, 3 ... Recording head, 15 ... Capping mechanism, 16 ... Wiping mechanism, 16 '... Wiper blade, 17 ... Humidifying liquid tank, 20 ... Piezoelectric vibrator, 20' ... Piezoelectric vibrator for humidifying liquid supply 27 ... Humidification liquid supply path, 31 ... Nozzle plate, 33 ... Reservoir, 33 '... Humidification liquid reservoir, 34 ... Ink supply port, 34' ... Humidification liquid supply port, 35 ... Pressure chamber, 35 '... Humidification Liquid supply pressure chamber, 37... Nozzle, 44. Nozzle array, 45. Humidification hole, 46. Introduction flow path, 47 .. communication flow path, 48 ... optical path, 49. prism

Claims (10)

A liquid ejecting head having a nozzle opening surface in which a nozzle is opened, filling a pressure chamber communicating with the nozzle with liquid, and applying a pressure fluctuation to the liquid in the pressure chamber, thereby ejecting liquid droplets from the nozzle. A liquid ejecting apparatus comprising:
A humidifying liquid supply means for supplying the humidifying liquid to the nozzle opening surface side;
A humidifying hole for supplying the humidifying liquid from the humidifying liquid supply means is formed at a position off the nozzle opening on the nozzle opening surface,
The liquid ejecting apparatus, wherein the humidifying hole holds the humidifying liquid by surface tension. The liquid jet head has a nozzle group in which the nozzles are arranged in a plurality of rows,
A plurality of the humidifying holes are formed in the nozzle opening surface,
2. The liquid ejecting apparatus according to claim 1, wherein each of the humidifying holes is arranged along a direction in which the nozzles are arranged.   The said humidification liquid supply means arrange | positions the humidification liquid storage part which stored the humidification liquid in the gravity direction upper direction with respect to the said nozzle opening surface, The Claim 1 or Claim 2 characterized by the above-mentioned. Liquid ejector. A wiping member for wiping the nozzle opening surface of the liquid jet head;
4. The liquid ejecting apparatus according to claim 1, wherein the humidifying holes are arranged so as not to be aligned with the nozzles in a wiping direction of the wiping member. 5.   5. The liquid ejecting apparatus according to claim 1, wherein the humidifying liquid supply unit includes a liquid feeding unit that supplies the humidifying liquid to the humidifying hole.   The liquid ejecting apparatus according to claim 5, further comprising a moisturizing liquid detecting unit configured to detect a moisturizing liquid held in the humidifying hole.   The humidifying liquid supply means supplies the humidifying liquid to the humidifying hole by driving the liquid feeding means when the moisturizing liquid detecting means does not detect the moisturizing liquid detecting means. Item 7. The liquid ejecting apparatus according to Item 6. The liquid is ink;
The liquid ejecting apparatus according to claim 1, wherein the moisturizing liquid includes one or more volatile components of ink.   The liquid ejecting apparatus according to claim 1, wherein a liquid repellent treatment is performed on the nozzle opening surface. A liquid ejecting head having a nozzle opening surface in which a nozzle is opened, capable of ejecting liquid droplets from the nozzle by filling the pressure chamber communicating with the nozzle with liquid and applying pressure fluctuations to the liquid in the pressure chamber. There,
A humidifying liquid supply means for supplying the humidifying liquid to the nozzle opening surface side;
A humidifying hole for supplying the humidifying liquid from the humidifying liquid supply means is formed at a position off the nozzle opening on the nozzle opening surface,
The liquid ejecting head, wherein the humidifying hole holds the humidifying liquid by surface tension.

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