JP2009184210A - Head assembly and liquid delivering apparatus containing this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize both suppressing fluctuation of pressure in a cap and preventing a nozzle from drying by the cap. <P>SOLUTION: A through-hole is formed in the cap 70 covering the delivering face 30a of a head 2, and a pipe 75 with a fine diameter is fitted in the through-hole. The pipe 75 makes the inside space of the cap 70 communicate with the outside space thereof through the through-hole, and is fixed so as to extend along the bottom part of the cap 70. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a head assembly including a head and a cap that covers a discharge surface of the head, and a liquid discharge apparatus including the head assembly.

  In an ink jet printer, a technique is known in which the ejection surface of a head is covered with a cap during non-printing to prevent drying of nozzles opened on the ejection surface and maintain a meniscus. Further, paying attention to pressure fluctuations in the cap, it has been proposed to provide an air opening on the side wall of the cap for communicating with the atmosphere inside the cap after the inside of the cap becomes negative (see Patent Document 1). .

  The cap as described above is also used when the head unit is stored for a long time or transported by an aircraft or the like. In this case, the head flow path is filled with a liquid suitable for long-term storage (hereinafter referred to as “preservation liquid”), and the discharge surface of the head is covered with a cap to protect the discharge surface and evaporate the storage liquid. Prevention is realized.

Japanese Patent No. 3587344

  As described in the above-mentioned document 1, by allowing the inside of the cap to communicate with the atmosphere, it is possible to prevent cracks in the actuator and liquid leakage from the nozzle that may occur in response to pressure fluctuations in the cap accompanying sudden changes in environmental temperature and pressure. . However, since the length of the passage of the atmosphere opening port in the document 1 is defined by the thickness of the side wall of the cap, it cannot be increased. Further, the cap is often molded from resin, and in the case of resin molding, it is difficult to make the diameter of the air opening provided in the side wall of the cap minute. As the passage length of the atmosphere opening port is shorter and the diameter of the atmosphere opening is larger, the effect of preventing the nozzle from drying by the cap is reduced. Therefore, the effect of maintaining the meniscus during non-printing and the storage during long-term storage or transportation There is a problem that the effect of preventing evaporation of the liquid cannot be sufficiently obtained.

  An object of the present invention is to provide a head assembly that can achieve both suppression of pressure fluctuation in the cap and prevention of drying of the nozzle by the cap, and a liquid ejection apparatus including the head assembly.

  In order to achieve the above object, according to an aspect of the present invention, a head having a discharge surface including a discharge region in which a plurality of nozzles are open, a concave shape, and the discharge region with respect to the discharge surface of the head. A cap including a tip that abuts so as to surround, and the cap is formed of a separate member, and the wall is connected to the inner space and the outer space of the cap through a through hole formed in the wall of the cap. A head assembly is provided, comprising an attached pipe and a support member for supporting the cap.

  According to the said structure, since a pipe consists of a cap and another member, the diameter and length of a pipe can be adjusted suitably. Therefore, by appropriately adjusting the diameter and length of the pipe, it is possible to achieve both the suppression of pressure fluctuation in the cap and the prevention of drying of the nozzle by the cap by setting the flow resistance value of the pipe to the air within a predetermined range. it can.

  The pipe may be bent at a part of its longitudinal direction. In this case, a long pipe can be arranged in a certain space. Moreover, the freedom degree of pipe length setting increases.

  The pipe may extend along a bottom portion of the cap that faces the discharge surface and extends in parallel with the discharge surface. In this case, as in the case described above, a long pipe can be arranged in a certain space, and the degree of freedom in setting the pipe length is increased.

  In the above case, it is preferable that a gap is formed between the pipe and the bottom. When a gap is not formed between the pipe and the bottom, the rigidity of the bottom of the cap increases and the adhesion of the cap to the ejection surface of the head decreases, but such a situation can be avoided.

  The through hole is formed in the bottom wall of the cap that faces the discharge surface and extends in parallel with the discharge surface, and the pipe extends from one end to the other end in a direction perpendicular to the discharge surface. It may be inclined with respect to. In this case, as in the case described above, a long pipe can be arranged in a certain space, and the degree of freedom in setting the pipe length is increased.

  The through hole is formed in the bottom wall of the cap that faces the discharge surface and extends in parallel with the discharge surface, and one end of the pipe protrudes in a direction from the wall toward the discharge surface. In this way, it may be inserted into the through hole. In this case, one end of the pipe protrudes in the direction from the bottom wall of the cap toward the discharge surface, so that even if liquid leaks from the nozzle and accumulates at the bottom of the cap, there is no liquid at one end of the pipe. Is suppressed from flowing in.

  In the above case, the one end of the pipe may be bent so as to intersect the insertion direction of the pipe into the through hole. Thereby, the detachment | leave from the cap of a pipe can be prevented effectively.

  One end of the pipe may be inserted into the through hole, and an end surface of the one end of the pipe may intersect with a direction orthogonal to the insertion direction of the pipe into the through hole. In this case, since the pipe can be easily inserted into the through hole at one end, the pipe can be easily attached to the cap.

  The cap may include a portion made of rubber including the tip and a portion made of resin that supports the cap. Compared with rubber, a resin can be used to mold a minute diameter through-hole and the like with a mold, but is expensive. Therefore, by making the cap a two-part configuration (two-color molded product) of rubber and resin, it is possible to achieve both cost reduction and accurate molding. In addition, since the tip that comes into contact with the discharge surface is made of rubber, it is possible to ensure the adhesion of the cap to the discharge surface.

  In the wall in which the through hole is formed, an inner portion facing the inner space is made of rubber, an outer portion facing the outer space is made of resin, and one end of the pipe is pressed by the inner portion. However, it may be inserted into the through hole. In this case, since the pipe is fixed by the elastic force of rubber, it is not necessary to use an adhesive for fixing the pipe. Moreover, pipes can be easily replaced and the product cost can be reduced by not using an adhesive.

  The bottom portion of the cap that faces the discharge surface and extends in parallel with the discharge surface is made of an inner portion facing the inner space made of rubber, and an outer portion facing the outer space made of resin. Good. In this case, it is possible to further reduce the cost by using rubber at the bottom of the cap, and the resin provides the bottom of the cap with durability and rigidity required for work.

  The pipe is preferably made of stainless steel. Since stainless steel has excellent corrosion resistance, even if liquid leaks from the nozzle and comes into contact with the pipe, corrosion of the pipe is suppressed.

  It is preferable that the through hole is formed at a position that does not face the ejection region. If the through hole is formed at a position facing the discharge area, the liquid easily adheres to the pipe in the event that the liquid leaks from the nozzle, but this problem can be reduced.

  The discharge region may have an elongated shape in one direction. In a head in which a discharge area is formed in one direction, such as a line type head, warpage of the discharge surface tends to increase in the one direction. Therefore, in order to bring the tip of the cap into contact with the ejection surface in the one direction, the cap needs to have a certain degree of elasticity, and it is necessary not to increase the rigidity of the cap. In the above configuration, since only the pipe is locally attached to the cap, an increase in the rigidity of the cap is suppressed, and elasticity for bringing the tip of the cap into contact with the ejection surface in the one direction is ensured. be able to.

  The flow path leading to the nozzle formed in the head may be filled with a liquid containing at least one of a metal rust inhibitor, a drying inhibitor, and a surfactant. This is a suitable form when the head unit is stored for a long period of time or transported by an aircraft or the like, and filling of the liquid prevents air and foreign matter from entering the flow path. The metal rust preventive agent prevents rusting of the metal member constituting the head, and the anti-drying agent contributes to preventing the liquid from evaporating and maintaining the effect of preventing air and foreign matter from entering the flow path. Furthermore, when the liquid contains an anti-drying agent and a surfactant, the surface tension of the liquid becomes small, so that bubbles are hardly generated in the liquid when the liquid is filled in the flow path.

  According to another aspect of the present invention, the liquid ejecting apparatus includes the head assembly and a transport unit that transports a recording medium on which recording is performed by the liquid ejected from the nozzle of the head. Is provided. According to this configuration, the same effect as that obtained by the head assembly described above can be obtained.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic sectional side view showing an embodiment of a head assembly according to the present invention. As shown in FIG. 1, the head assembly 1 according to this embodiment includes an inkjet head 2, a cap 70 that covers the ejection surface 30 a that is the bottom surface of the inkjet head 2, and a support unit 110 that supports the head 2 and the cap 70. Have. The inkjet head 2 has a substantially rectangular parallelepiped shape elongated in the left-right direction in the drawing.

  First, the inkjet head 2 will be described. FIG. 2 is a diagram showing only the head 2 in a cross section taken along line II-II in FIG.

  As shown in FIG. 2, the inkjet head 2 stores a head main body 13 including a flow path unit 4 and a piezoelectric actuator 21, and ink or a storage liquid (hereinafter collectively referred to as “liquid”) supplied to the head main body 13. Reservoir unit 90, a flexible printed circuit (FPC) 50 on which a driver IC 52 for supplying a drive signal to the piezoelectric actuator 21 is mounted, a control board 54 electrically connected to the FPC 50, and a piezoelectric actuator 21, the reservoir unit 90, the FPC 50, and a cover 58 that covers the control board 54.

  The control board 54 is disposed horizontally above the reservoir unit 90. One end of the FPC 50 is fixed to the upper surface of the piezoelectric actuator 21, and the FPC 50 is pulled out from between the lower surface of the reservoir unit 90 and the piezoelectric actuator 21 to the upper side of the reservoir unit 90 along the side surface of the reservoir unit 90. The end is connected to the connector 54 a of the control board 54. The driver IC 52 is fixed to a portion of the FPC 50 that extends along the side surface of the reservoir unit 90. Based on a command from the control board 54, the driver IC 52 sends a drive signal to the piezoelectric actuator 21 via wiring provided on the FPC 50. Supply.

  The reservoir unit 90 is fixed to the upper surface of the flow path unit 4 in the head main body 13 where the piezoelectric actuator 21 is not disposed. The reservoir unit 90 is formed with a reservoir 90a for storing liquid, and the reservoir 90a communicates with an opening 5b (see FIG. 3) formed on the upper surface of the flow path unit 4. Therefore, the liquid in the reservoir 90a is supplied to the flow path unit 4 through the opening 5b.

  The cover 58 includes an upper cover 55 disposed above the control board 54 and two side covers 53 disposed to face each other in the short direction of the flow path unit 4 so as to sandwich the reservoir unit 90 therebetween.

  Each side cover 53 is a plate-like member made of a metal material, and has a substantially rectangular outer shape extending in the vertical direction and the longitudinal direction of the flow path unit 4 as shown in FIG. The side cover 53 extends over substantially the entire length in the longitudinal direction of the flow path unit 4 as shown in FIG. 1, and is fixed near both ends in the short direction on the upper surface of the flow path unit 4 as shown in FIG. ing. A sealing member 56 made of silicone resin or the like is applied from the outside along the longitudinal direction of the side cover 53 at the contact portion of the side cover 53 with the flow path unit 4, that is, the lower end of the side cover 53. By the sealing member 56, the side cover 53 is securely fixed to the flow path unit 4, and the ink mist into the space in the cover 58 through the gap between the lower end of the side cover 53 and the upper surface of the flow path unit 4. Etc. are prevented.

  The upper cover 55 is a plate-like member made of a metal material similarly to the side cover 53, and covers the vicinity of the upper end of the side cover 53 and the vicinity of both ends in the longitudinal direction so as to contact from the outside as shown in FIG. The upper surface of the reservoir base plate 92 included in the reservoir unit 90 is fixed. Sealing members 56 are applied from the outside to the engaging portion of the upper cover 55 with the side cover 53 and the contact portion of the upper cover 55 with the reservoir base plate 92, respectively. The upper cover 55 is securely fixed to the side cover 53 and the reservoir base plate 92 by the sealing member 56, and ink mist to the closed space 100 formed by the upper cover 55, the side cover 53, and the reservoir base plate 92, etc. Intrusion is prevented.

  As shown in FIGS. 1 and 2, a through hole 102 is formed in the approximate center of the upper portion of the upper cover 55 so as to communicate the closed space 100 and the space outside the cover 58. The diameter of the through hole 102 is preferably 0.1 to 1.0 mm from the viewpoint of realizing both the prevention of intrusion of ink mist and the like into the closed space 100 and the above communication, and in this embodiment, the diameter is about 0.2 mm. is there. Thereby, even if the pressure in the outer space of the cover 58, that is, the atmospheric pressure around the inkjet head 2, changes, the pressure in the closed space 100 and the ambient atmospheric pressure are kept the same.

  As shown in FIG. 2, an elastic sponge 51 is affixed to the inner side of the portion of the FPC 50 where the driver IC 52 is fixed and facing the side surface of the reservoir unit 90. The driver IC 52 is pressed against the side cover 53 via the FPC 50 by the elastic force of the sponge 51. Heat generated in the driver IC 52 is quickly dissipated through the side cover 53 and the upper cover 55. That is, the side cover 53 and the upper cover 55 also have a heat dissipation function.

  FIG. 3 is a plan view of the head body 13. FIG. 4 is an enlarged view of a region IV surrounded by an alternate long and short dash line in FIG. FIG. 5 is a sectional view taken along line VV in FIG. In FIG. 4, the piezoelectric actuator 21 is drawn with a two-dot chain line, and the aperture 12 and the nozzle 8 that are to be drawn with a broken line inside the flow path unit 4 are shown with a solid line for easy understanding of the positional relationship of each component. I'm drawing.

  As shown in FIG. 3, four piezoelectric actuators 21 each having a trapezoidal shape are fixed to the upper surface of the flow path unit 4. The piezoelectric actuators 21 are arranged in two rows in a staggered manner along the longitudinal direction of the flow path unit 4. As shown in FIG. 4, pressure chambers 10 each having a substantially rhombus shape and arranged in a matrix are opened in an area corresponding to the adhesion area of each piezoelectric actuator 21 on the upper surface of the flow path unit 4. . Further, on the lower surface of the flow path unit 4, that is, on the discharge surface 30 a, minute diameter nozzles 8 communicating with the pressure chambers 10 are opened in regions corresponding to the adhesion regions of the piezoelectric actuators 21 as shown in FIG. 5. ing. Hereinafter, an area corresponding to the adhesion area of each piezoelectric actuator 21 on the ejection surface 30a is referred to as an “ejection area”.

  In the flow path unit 4, as shown in FIG. 3, a manifold flow path 5 communicating with the opening 5 b, and a branch from the manifold flow path 5 along the longitudinal direction of the flow path unit 4 in the adhesion region of the piezoelectric actuator 21. And a sub-manifold channel 5a extending. Four sub-manifold channels 5 a are formed in the adhesion region of each piezoelectric actuator 21.

  Further, as shown in FIG. 5, an individual flow path 32 is formed in the flow path unit 4 from the outlet of the sub manifold flow path 5 a to the nozzle 8 through the aperture 12 functioning as a throttle and the pressure chamber 10. Has been.

  As shown in FIG. 5, the flow path unit 4 includes a cavity plate 22, a base plate 23, an aperture plate 24, a supply plate 25, manifold plates 26, 27, 28, a cover plate 29, and a nozzle plate 30 in order from the top. It has 9 metal plates. Each of these metal plates 22 to 30 is formed with holes constituting the individual flow paths 32, and by bonding the nine metal plates while aligning each other so that the individual flow paths 32 are formed, A flow path unit 4 is formed. The piezoelectric actuator 21 is bonded to the upper surface of the flow path unit 4 so as to close the opening of the pressure chamber 10 formed on the upper surface of the flow path unit 4.

  FIG. 6 is a longitudinal sectional view of the reservoir unit 90. As shown in FIGS. 2 and 6, the reservoir unit 90 includes a lower reservoir 95 made of metal and an upper reservoir 91 made of resin disposed on the lower reservoir 95. The lower reservoir 95 and the upper reservoir 91 are fixed to each other by screws.

  As shown in FIG. 6, a flow path 96 is formed in the upper reservoir 91 from the supply port 96 a to a later-described through hole 61 formed in the lower reservoir 95. The supply port 96a is connected to an ink tank or a storage liquid tank via a tube (not shown) or the like. A flexible damper film 101 is provided below the upper reservoir 91 so that a gap is formed between the lower reservoir 95 and the flow path 96. The damper film 101 attenuates the vibration of the liquid in the flow path 96. Since the through-hole 102 is provided in the upper cover 55 so that the pressure in the closed space 100 and the air pressure around the inkjet head 2 are kept the same, the damper film 101 can be freely moved without being restricted by the pressure in the closed space 100. Transforms into

  A filter 97 is provided at a position facing the damper film 101 in the flow path 96. The liquid supplied from the supply port 96 a flows into the lower reservoir 95 after the foreign matter is removed by the filter 97.

  The lower reservoir 95 includes three metal plates, a reservoir base plate 92, a reservoir plate 93, and an under plate 94, in order from the top. These plates 92 to 94 have an elongated rectangular shape in the same direction as the flow path unit 4 and are aligned and bonded to each other. The length in the short direction of the plates 92 to 94 is shorter than the distance between the two side covers 53 as shown in FIG. The length of the reservoir base plate 92 in the longitudinal direction is longer than the lengths of the reservoir plate 93 and the under plate 94 in the longitudinal direction, as shown in FIGS. 1 and 6. Accordingly, both ends of the reservoir base plate 92 in the longitudinal direction protrude outward from both ends of the reservoir plate 93 and the under plate 94.

  A through hole 61 is formed in the approximate center of the reservoir base plate 92. The reservoir plate 93 is formed with a through hole that forms the reservoir 90a. In the under plate 94, through holes 63 corresponding to the ten openings 5 b (see FIG. 3) of the flow path unit 4 are formed in a region other than the region facing the piezoelectric actuator 21. The liquid supplied to the flow path 96 of the upper reservoir 91 is dropped into the center of the reservoir 90a through the through hole 61, and then flows horizontally in the reservoir 90a, and is distributed to each through hole 63, through the opening 5b. It flows into the flow path unit 4 through.

  A recess 94 a is formed in a region facing the piezoelectric actuator 21 bonded on the flow path unit 4 on the lower surface of the under plate 94. In other words, the portion including the periphery of the opening of the through hole 63 on the lower surface of the under plate 94 protrudes downward. The protruding portion is fixed to the upper surface of the flow path unit 4, and the piezoelectric actuator 21 is disposed in the gap between the flow path unit 4 and the lower reservoir 95 formed by the recess 94 a.

  The present embodiment is a form applied when the head 2 alone is stored for a long time or transported by an aircraft or the like, and the flow path in the reservoir unit 90 and the flow path unit 4 is filled with a storage liquid instead of ink, Intrusion of air and foreign matter into the flow path is prevented. The preservation solution contains a metal rust inhibitor, a drying inhibitor, and a surfactant. The metal rust inhibitor prevents rust of the metal member constituting the head 2, and the drying inhibitor prevents evaporation of the preservation solution and maintains the effect of preventing the intrusion of air and foreign matter into the flow path. In addition, since the storage liquid contains an anti-drying agent and a surfactant, the surface tension of the storage liquid is reduced, and the storage liquid is filled when the storage liquid is filled into the flow paths in the reservoir unit 90 and the flow path unit 4. Air bubbles are less likely to be generated. In the present embodiment, the preserving liquid is obtained by excluding the color material from the ink composition.

  Next, the cap 70 will be described with reference to FIGS. 1 and 7. FIG. 7 is an enlarged view of a region VII surrounded by an alternate long and short dash line in FIG.

  As shown in FIG. 1, the cap 70 has a concave shape and covers the ejection surface 30 a of the head 2. The cap 70 includes a rubber member 71 including a rectangular bottom 71b extending in parallel with the discharge surface 30a, and a tip 71a protruding from the entire outer edge of the bottom 71b in a direction perpendicular to the bottom 71b, and the bottom 71b. The resin plate 72 adhered to cover the entire lower surface of the lower surface. The resin plate 72 has a smaller thickness than the bottom 71 b of the rubber member 71.

  The bottom 71b and the resin plate 72 are opposed to a region excluding the vicinity of both ends in the longitudinal direction of the discharge surface 30a, that is, a region including four discharge regions (bonding regions of the four piezoelectric actuators 21 shown in FIG. 3) on the discharge surface 30a. ing. The tip 71a of the rubber member 71 is in contact with the discharge surface 30a along the outline surrounding the four discharge regions.

  As shown in FIGS. 1 and 7, a part of the resin plate 72 protrudes downward so that a columnar space 72a is formed between the bottom surface of the bottom 71b. A through hole 71x having the same shape and diameter as the space 72a in plan view is formed in a portion corresponding to the space 72a in the bottom 71b. The through hole 71x and the space 72a are formed at a position corresponding to a position between the two openings 5b as shown in FIG. 3, for example, and not facing the discharge area.

  Further, as shown in FIG. 7, a minute diameter through hole 72 x that connects the inner space 70 a and the outer space of the cap 70 is formed in the side wall that defines the space 72 a of the resin plate 72. The tip of a stainless steel pipe 75 is inserted into the through hole 72x. That is, the pipe 75 communicates the inner space 70a and the outer space of the cap 70 through the through hole 72x.

  The pipe 75 has a cylindrical shape with both end faces opened, and is along the bottom of the cap 70, that is, parallel to a portion excluding the side wall defining the space 72 a in the bottom 71 b and the resin plate 72, and the resin plate It extends while forming a gap t between 72 and the above portion. As shown in FIG. 1, the rear end of the pipe 75 is engaged with a hook 72b formed on the resin plate 72, and is fixed to the hook 72b with an adhesive or the like. As shown in FIG. 7, the end surface of the tip of the pipe 75 intersects the direction orthogonal to the insertion direction of the pipe 75 into the through hole 72x, that is, the vertical direction in FIG.

  Next, the support unit 110 will be described with reference to FIG.

  The support unit 110 has a substrate 80 that is slightly larger than the head 2 in plan view, two cylindrical support rods 86 that are attached to stand upright on the substrate 80, and a lower end fixed on the substrate 80. Two springs 85 are provided. By supporting the vicinity of both ends in the longitudinal direction of the reservoir base plate 92 on the upper end of the support bar 86 and screwing the screws S1 into the screw holes formed in the plate 92, the reservoir base plate 92 is fixed to the support bar 86, and the head 2 The whole is supported by the support rod 86 and the substrate 80.

  The upper ends of the springs 85 are respectively fixed to the lower surfaces of the resin plate 72 in the vicinity of both ends in the longitudinal direction. Therefore, the cap 70 is supported while being biased from below by the spring 85.

  As described above, according to the head assembly 1 according to the present embodiment, for example, when the head assembly 1 is transported by an aircraft or the like, the pipe 75 remains in the inner space of the cap 70 even if the environmental temperature or pressure changes suddenly. Since 70a and outer space are connected, the pressure fluctuation of inner space 70a is suppressed. As a result, cracks in the piezoelectric actuator 21 and liquid leakage from the nozzle 8 that can occur with pressure fluctuations in the inner space 70a are prevented.

  Furthermore, since the pipe 75 is made of a separate member from the cap 70, the diameter and length of the pipe 70 can be adjusted as appropriate. Therefore, by appropriately adjusting the diameter and length of the pipe 75, the flow resistance value of the pipe 75 with respect to the air is set within a predetermined range, and both the suppression of pressure fluctuation in the cap 70 and the prevention of drying of the nozzle 8 by the cap 70 are achieved. Can be realized.

  From the viewpoint of realizing both suppression of pressure fluctuation in the cap 70 and prevention of drying of the nozzle 8 by the cap 70, the inner diameter of the pipe 75 is 0.3 to 0.8 mm, and the flow resistance value of the pipe 75 to the air is It is preferably 0.2 to 0.62 kpa · sec / cc. The channel resistance value has a correlation with each of the inner diameter and the length of the pipe 75. Generally, the smaller the inner diameter of the pipe 75 and the longer the length, the larger the channel resistance value. Therefore, it is desirable to set the inner diameter and length of the pipe 75 so that the flow path resistance value is in the above range.

  Since the pipe 75 extends along the bottom of the cap 70, the long pipe 75 can be disposed in a certain space, and the degree of freedom in setting the length of the pipe 75 is increased.

  When the gap t is not formed between the pipe 75 and the bottom of the cap 70, that is, when the pipe 75 is in contact with the bottom of the cap 70, the rigidity of the bottom of the cap 70 increases, and the elasticity of the cap 70 increases. It will fall and the adhesiveness of the cap 70 with respect to the discharge surface 30a of the head 2 will fall. On the other hand, in the present embodiment, as shown in FIG. 7, the gap t is formed between the pipe 75 and the bottom of the cap 70, so that the above situation can be avoided.

  The end surface of the tip inserted into the through hole 72x in the pipe 75 intersects the direction orthogonal to the insertion direction of the pipe 75 into the through hole 72x. Therefore, since the pipe 75 can be easily inserted into the through hole 72x, the pipe 75 can be easily attached to the cap 70.

  The cap 70 includes a rubber member 71 and a resin plate 72. Compared to rubber, resin can be used to mold a minute diameter through-hole 72x and the like relatively accurately using a mold, but is expensive. Therefore, by making the cap 70 into a two-part configuration (two-color molded product) of rubber and resin, both cost reduction and accurate molding can be achieved. In addition, since the tip 71a that comes into contact with the discharge surface 30a is made of rubber, it is possible to ensure adhesion of the cap 70 to the discharge surface 30a.

  As for the bottom part of the cap 70, the inner part facing the inner space 70a is made of rubber, and the outer part is made of resin. Thus, the rubber can be further reduced by using rubber at the bottom of the cap 70, and the resin plate 72 provides the bottom of the cap 70 with durability and rigidity required for work. .

  Since the pipe 75 is made of stainless steel having excellent corrosion resistance, even if liquid leaks from the nozzle 8 and comes into contact with the pipe 75, corrosion of the pipe 75 is suppressed.

  If the through holes 71x, 72x and the space 72a are formed at positions facing the discharge area, the liquid is likely to adhere to the pipe 75 if the liquid leaks from the nozzle 8, but in this embodiment, the through hole Since the 71x, 72x and the space 72a are formed at positions that do not face the ejection region, the above-described problems can be reduced.

  In the head 2 that is long in one direction as in the present embodiment, it is very difficult to keep the flatness of the discharge surface 30a completely, and the warpage of the discharge surface 30a tends to increase in the one direction. Therefore, in order to bring the tip 71a of the cap 70 into contact with the ejection surface 30a in the one direction, the cap 70 needs to have a certain degree of elasticity, and it is necessary not to increase the rigidity of the cap 70. For example, when a relatively large member other than the pipe 75 is attached to the cap 70 as a member for communicating the inner space 70a and the outer space of the cap 70, the rigidity of the cap 70 increases. On the other hand, in this embodiment, since only a small diameter pipe 75 is locally attached to the cap 70, an increase in the rigidity of the cap 70 is suppressed, and the tip 71a of the cap 70 extends in the one direction. It is possible to ensure elasticity for bringing the liquid into contact with the discharge surface 30a.

  Next, a modified example of the cap and the pipe will be described with reference to FIGS. 8 (a), (b), and (c).

  8A, 8B, and 8C, the cap 170 includes a rubber member 171 and a resin that are substantially the same as the rubber member 71 and the resin plate 72 included in the cap 70 of the above-described embodiment. Plate 172. The resin plate 172 is different from the above-described resin plate 72 in that it has a through-hole 172 having a small diameter into which the tip of the pipe 175 is inserted instead of the protruding portion that forms the space 72a (see FIG. 7). The bottom portion 171b of the rubber member 171 has the above-described bottom portion in that it has a through hole 171x slightly smaller than the through hole 172x at a position corresponding to the through hole 172x of the resin plate 172 instead of the through hole 71x corresponding to the space 72a. It is different from 71b.

  The pipe 175 shown in FIG. 8A has substantially the same shape as the above-described pipe 75, but the insertion direction into the cap and the arrangement in the apparatus are different from the above-described pipe 75. The pipe 175 is inserted into the through holes 171x and 172x so that the tip of the pipe 175 protrudes upward from the upper surface of the bottom 171b, and is fixed to the cap 170 in an inclined state with respect to the vertical direction. By inclining the pipe 175 in this manner, as in the above-described embodiment, it is possible to arrange the long pipe 175 in a certain space and to obtain an effect that the degree of freedom in setting the length of the pipe 175 is increased.

  A pipe 275 shown in FIG. 8 (b) is obtained by bending a part of the above-described pipe 175 in the longitudinal direction. Like the pipe 175, the pipe 275 has a through hole so that the tip projects upward from the upper surface of the bottom 171b. It is inserted in 171x and 172x, and it is being fixed to the cap 170 so that the part except a bending part may follow a perpendicular direction. By bending a part of the pipe 275 in the longitudinal direction as described above, the long pipe 275 can be disposed in a certain space as described above, and the degree of freedom in setting the length of the pipe 275 is increased. can get.

  A pipe 375 shown in FIG. 8C is obtained by bending the tip of the pipe 175 at a right angle. The pipe 375 is formed in the through holes 171x and 172x so that the tip including the bent part protrudes upward from the upper surface of the bottom 171b. The portion is inserted and fixed to the cap 170 so that the portion excluding the bent portion is along the vertical direction. In this way, the pipe 375 can be effectively prevented from being detached from the cap 170 by bending the tip of the pipe 375 at a right angle to the direction of insertion into the through holes 171x and 172x.

  8A to 8C, the ends of the pipes 175, 275, and 375 protrude from the upper surface of the rubber member 171 toward the discharge surface 30a, that is, upward. Therefore, even if the liquid leaks from the nozzle 8 and accumulates on the upper surface of the rubber member 171, the liquid is suppressed from flowing into the tip of the pipe 175.

  8A to 8C, the ends of the pipes 175, 275, and 375 are inserted into the through holes while being pressed by the rubber member 171. In this case, since the pipes 175, 275, and 375 are fixed by the elastic force of rubber, it is not necessary to use an adhesive for fixing the pipe. Moreover, pipes can be easily replaced and the product cost can be reduced by not using an adhesive.

  Next, an embodiment of a liquid ejection apparatus according to the present invention will be described with reference to FIGS. In the present embodiment, the same components as those described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 9 is a schematic sectional side view showing an ink jet printer as an embodiment of the liquid ejection apparatus according to the present invention. As shown in FIG. 9, the printer 500 according to the present embodiment is a color inkjet printer having four heads 2. The reservoir unit 90 in each head 2 and the flow path in the flow path unit 4 are filled with inks of magenta, yellow, cyan, and black. The four heads 2 are fixed to a frame 504 that is movable in the vertical direction.

  The printer 500 is provided with a paper feed tray 511 on the left side in the drawing and a paper discharge tray 513 on the right side in the drawing, and the paper is conveyed from the paper feed tray 511 toward the paper discharge tray 513. A conveyance path is formed. By the pickup roller 516, the uppermost sheet among the sheets stored in the sheet feed tray 511 is sent out to the transport unit 512.

  The conveyance unit 512 is disposed at a position facing the head 2 in an area surrounded by the two rollers 506 and 507, an endless conveyance belt 508 wound between the two rollers 506 and 507, and the conveyance belt 508. Platen 509. The sheet sent out from the paper feed tray 511 is pressed against the surface of the conveyor belt 508 by the pressing roller 505, and then supported on the conveyor belt 508, while the conveyor belt 508 is driven by the driving of the roller 506 in FIG. It is conveyed along the direction of the thick arrow. When the paper transported by the transport belt 508 sequentially passes immediately below the four heads 2, each color ink is ejected from the ejection surface 30a of each head 2, thereby forming a desired color image on the surface of the paper. Is done. Thereafter, the sheet is peeled off from the surface of the conveyor belt 508 by the peeling plate 514 and stored in the paper discharge tray 513.

  FIG. 10 is a schematic plan view of a main part of the printer 500 shown in FIG. As shown in FIG. 10, the frame 504 holds the four heads 2 in the frame and moves in the vertical direction by a pair of moving mechanisms 551 disposed on both sides of the frame 504 with respect to the short direction of the head 2. Supported as possible. Each moving mechanism 551 includes a motor 552, a pinion gear 553 fixed to the shaft of the motor 552, a rack gear 554 meshed with the pinion gear 553, and a guide 555 that sandwiches the rack gear 554 with the pinion gear 553. The frame 504 is fixed at the printing position shown in FIG. 1 during printing, and moved to a maintenance position above the printing position by driving the moving mechanism 551 during maintenance.

  The cap 70 is included in the maintenance unit 570. The maintenance unit 570 is disposed at the retracted position on the back side of the paper surface of the head 2 shown in FIG. 9 during printing, and is driven from the retracted position toward the front of the paper surface in FIG. The operation related to the maintenance is performed below the head 2 as will be described later.

  The maintenance unit 570 includes two trays 571 and 575 that are both movable in the horizontal direction and detachable from each other. The tray 571 has a box shape with the top open, and a U-shaped holding member 574 that holds the wiper 572 and the ink receiving member 572 is fixed to the side near the head 2 on the upper surface of the bottom. ing. The tray 575 has a pair of hooks 566 that can be engaged with a pair of grooves 565 formed in the holding member 574. Therefore, when the tray 571 moves in the horizontal direction, the tray 575 moves together while being accommodated in the tray 571 when the engagement is realized, and moves with the tray 571 when the engagement is released. Without being held in the retracted position. The cap 70 is fixed to the tray 575.

  The moving mechanism 591 extends in the same direction as the motor 592, the motor pulley 593 connected to the shaft of the motor 592, the idle pulley 594, the timing belt 595 spanned between the motor pulley 593 and the idle pulley 594, and the timing belt 595. And a pair of guide shafts 596a, 596b and bearing members 597a, 597b, 598a, 598b engaged with the guide shafts 596a, 596b, respectively. The bearing members 597a and 597b are fixed to the tray 571, and the bearing members 598a and 598b are fixed to the tray 575, respectively. The bearing member 597a is connected to the timing belt 595. Accordingly, the tray 571 moves in the horizontal direction as the timing belt 595 is driven by driving the motor 592.

  In the present embodiment, “maintenance” refers to a recovery operation for recovering the head 2 when the nozzle 8 is not ejected correctly, and the cap 70 to the ejection surface 30a to prevent the nozzle 8 from drying when printing is not performed for a long time. It means capping.

  In the recovery operation, the cap 70 is not used and is held at the retracted position. First, after the head 2 is moved to the maintenance position, only the tray 571 moves to the right in FIG. Then, the ink is forcibly ejected from the nozzles 8 of the heads 2 to an area where the holding member 574 in the tray 571 is not fixed. The discharged ink is received by the tray 571 and then flows into a waste ink tank (not shown).

  Accompanying the ejection, ink droplets adhere to the ejection surface 30a of the head 2, and the ink droplets are removed by the ink receiving member 573 and the wiper 572 when the tray 571 moves to the left in FIG. . The ink receiving member 573 has a plurality of thin plates extending in the short direction of the head 2 and having a length equal to or longer than the entire length of the four heads 2, and each thin plate is as small as about 0.5 mm. A relatively large ink droplet on the ejection surface 30a is received by capillary force by being moved relatively while facing the ejection surface 30a through the gap. The wiper 572 is an elastic plate-like member that extends along the short direction of the head 2 and has a length equal to or longer than the entire length of the four heads 2. The ink droplets on the ejection surface 30a are wiped off by relatively moving them.

  At the time of capping, first, the head 2 is moved to the maintenance position, and then moved to the right in FIG. 10 with the tray 571 and the tray 575 being connected to each other. Then, the tips 71 a of the four caps 70 in the tray 575 are brought into contact with the discharge surfaces 30 a of the corresponding heads 2, and the discharge surfaces 30 a are covered with the caps 70. Thereby, drying of the nozzle 8 is prevented and the meniscus is maintained.

  As in the above-described embodiment, a pipe 75 that connects the inner space and the outer space of the cap 70 is attached to each cap 70. Therefore, even if the environmental temperature or pressure changes suddenly while the printer 500 is not used for a long period of time, the pressure fluctuation in the cap 70 is suppressed. Therefore, cracks in the piezoelectric actuator 21 and ink leakage from the nozzles 8 that can be caused by pressure fluctuations in the cap 70 are prevented. Further, from the same viewpoint as the above-described embodiment, by appropriately adjusting the diameter and length of the pipe 75, the flow resistance value against the air of the pipe 75 is set within a predetermined range, and pressure fluctuation in the cap 70 is suppressed and the cap Both prevention of drying of the nozzle 8 by 70 can be realized.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims.

  For example, in the embodiment of FIG. 1, the pipe 75 may extend while contacting the bottom surface of the cap 70 without forming the gap t. Further, the pipe 75 has its tip inserted into a through-hole formed in the bottom of the cap as in the modification shown in FIGS. 8A to 8C, and bent in an L shape below the bottom. Later, it may extend along the bottom.

  The pipe may be attached to the side wall instead of the bottom of the cap.

  The tip of the pipe may not protrude from the wall in the cap where the through hole is formed.

  The end surface of the tip of the pipe is not limited to intersecting the direction orthogonal to the insertion direction into the through hole of the pipe, and may be along the orthogonal direction, for example.

  The shape of the pipe can be changed in various ways, for example, it may be linear over its entire length.

  The inner diameter of the pipe is not limited to be constant over the entire length, and may be reduced in a part of the longitudinal direction, for example.

  The pipe may be made of metal other than stainless steel, resin, and various other materials.

  The cap is not limited to a two-component configuration of rubber and resin, and may be formed of, for example, rubber alone, resin alone, or other materials.

  The pipe insertion through-hole in the cap may be formed at a position facing the discharge region.

  The attachment of the pipe to the cap is not limited to being realized by inserting the pipe into a through hole formed in the wall of the cap as in the above-described embodiments and modifications. For example, the pipe may be attached to the cap by engaging the pipe with a portion protruding from the vicinity of the through hole or by adhering the tip of the pipe to the wall around the through hole.

  The head and its ejection surface are not limited to being elongated in one direction.

  In the head assembly according to the present invention, the liquid filled in the flow path of the head is not limited to the storage liquid having the above components, and may have other appropriate components.

  The through holes 102 may be provided at an arbitrary position of the cover 58, and the number thereof is not limited to one and may be two or more. For example, by providing the cover 58 with a filter having a large number of through holes 102, communication between the closed space 100 and the space outside the cover 58 and prevention of intrusion of ink mist or the like into the closed space 100 may be realized. Further, the through hole 102 may be omitted.

  The liquid ejection apparatus according to the present invention is not limited to the line type, but can be applied to a serial type in which the head reciprocates. Further, the present invention is not limited to a printer, and can be applied to a facsimile, a copier, and the like.

It is a schematic sectional side view which shows one Embodiment of the head assembly which concerns on this invention. It is a figure which shows only a head in the cross section along the II-II line | wire of FIG. It is a top view of a head body. FIG. 4 is an enlarged view of a region IV surrounded by an alternate long and short dash line in FIG. 3. FIG. 5 is a sectional view taken along line VV in FIG. 4. It is a longitudinal cross-sectional view of a reservoir unit. It is an enlarged view of the area | region VII enclosed with the dashed-dotted line in FIG. It is the elements on larger scale which show the modification of a cap and a pipe. 1 is a schematic sectional side view showing an ink jet printer as an embodiment of a liquid ejection apparatus according to the present invention. FIG. 10 is a schematic plan view of a main part of the printer shown in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Head assembly 2 Head 8 Nozzle 30a Discharge surface 70; 170 Cap 70a Inner space 71 Rubber member 71a Tip 71b Bottom 72 Resin plate (bottom)
72x; 171x, 172x Through hole 75; 175; 275; 375 Pipe 80 Substrate (support member)
85 Spring (support member)
171 Rubber member (inner part)
172 Resin plate (outer part)
500 Inkjet printer (liquid ejection device)
512 Conveying unit 575 Tray (supporting member)

Claims (16)

A head having a discharge surface including a discharge region in which a plurality of nozzles are opened;
A cap having a concave shape and including a tip that contacts the discharge surface of the head so as to surround the discharge region;
The pipe is made of a member different from the cap, and is a pipe attached to the wall so as to communicate the inner space and the outer space of the cap through a through hole formed in the wall of the cap.
A support member for supporting the cap;
A head assembly comprising:   The head assembly according to claim 1, wherein the pipe is bent at a part in a longitudinal direction thereof.   The head assembly according to claim 1, wherein the pipe extends along a bottom portion of the cap that faces the discharge surface and extends in parallel with the discharge surface.   The head assembly according to claim 3, wherein a gap is formed between the pipe and the bottom. The through hole is formed in the bottom wall of the cap that faces the discharge surface and extends in parallel with the discharge surface;
The head assembly according to claim 1, wherein the pipe is inclined from one end to the other end with respect to a direction orthogonal to the discharge surface. The through hole is formed in the bottom wall of the cap that faces the discharge surface and extends in parallel with the discharge surface;
The head assembly according to claim 1, wherein one end of the pipe is inserted into the through hole so as to protrude in a direction from the wall toward the discharge surface.   The head assembly according to claim 6, wherein the one end of the pipe is bent so as to intersect an insertion direction of the pipe into the through hole. One end of the pipe is inserted into the through hole,
The head assembly according to any one of claims 1 to 7, wherein an end surface of the one end of the pipe intersects a direction orthogonal to a direction in which the pipe is inserted into the through hole.   The head assembly according to any one of claims 1 to 8, wherein the cap includes a portion made of rubber including the tip and a portion made of a resin that supports the cap. The wall in which the through hole is formed has an inner portion facing the inner space made of rubber, and an outer portion facing the outer space made of resin.
The head assembly according to claim 9, wherein one end of the pipe is inserted into the through hole while being pressed by the inner portion.   The bottom portion of the cap that faces the discharge surface and extends in parallel with the discharge surface has an inner portion facing the inner space made of rubber and an outer portion facing the outer space made of resin. The head assembly according to claim 9 or 10, wherein:   The head assembly according to any one of claims 1 to 11, wherein the pipe is made of stainless steel.   The head assembly according to claim 1, wherein the through hole is formed at a position not facing the ejection region.   The head assembly according to any one of claims 1 to 13, wherein the discharge region has an elongated shape in one direction.   The flow path leading to the nozzle formed in the head is filled with a liquid containing at least one of a metal rust inhibitor, a drying inhibitor, and a surfactant. The head assembly according to any one of the above. The head assembly according to any one of claims 1 to 15,
A transport unit that transports a recording medium on which recording is performed by the liquid ejected from the nozzle of the head;
A liquid ejecting apparatus comprising:

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