JP2007216563A - Liquid jet head and liquid jet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet head which can favorably eject liquid droplets, and also which can surely discharge bubbles in a filter chamber when it performs the suction action, and to provide a liquid jet apparatus. <P>SOLUTION: The liquid jet head comprises a first member 21 with a first feeding passage 24 whose one end side communicates with a head body, a second member 26 with a second feeding passage 48 whose one end side communicates with the first feeding passage 24 and whose the other end side communicates with a storage means, and a filter 27 set between the first and second members and held to be able to deform in accordance with a change of the flow velocity of the liquid. The filter 27 is arranged in the filter chamber 51, and the filter chamber 51 consists of a first filter chamber 52 and a second filter chamber 53. Moreover, the first filter chamber 52 has its internal diameter made wider towards the filter 27 side and is comprised of a first and a second expansion parts 54 and 55. A tilting angle of the first expansion part 54 is made smaller than a tilting angle of the second expansion part 55. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid ejecting head and a liquid ejecting apparatus that eject droplets from nozzles, and more particularly to an ink jet recording head and an ink jet recording apparatus that supply ink from an ink cartridge and eject ink droplets from the nozzles.

  As a typical example of the liquid ejecting head, for example, an ink jet recording head can be cited. In this ink jet recording head, ink is generally applied to the head main body from an ink cartridge filled with ink through a flow path of an ink supply needle inserted into the ink cartridge and a holding member holding the ink cartridge. The supplied ink supplied to the head main body is ejected from the nozzle by driving a piezoelectric element or the like.

  In such an ink jet recording head, if bubbles that are present in the ink of the ink cartridge or bubbles that are mixed in the ink when the ink cartridge is attached / detached are supplied to the head body, such as dot dropout due to the bubbles. There is a problem that defective discharge occurs. In order to solve such a problem, a filter for removing bubbles or the like in the ink is mounted between the ink supply needle inserted into the ink cartridge and the base on which the ink supply needle is fixed. There is something like that (see, for example, Patent Document 1).

  By providing such a filter, bubbles are trapped by the filter when ink is ejected, so that bubbles can be prevented from flowing into the head body (recording head). The bubbles trapped in the filter are generally discharged from the nozzle by a so-called suction operation (cleaning operation) in which ink is sucked from the nozzle. That is, by sucking ink from the nozzle and causing the ink to generate a flow rate that is faster than the flow rate of ink during normal ink ejection, the bubbles pass through the filter together with the ink and are discharged from the nozzle.

  However, a relatively large pressure is required for air bubbles to pass through the filter during the suction operation. For this reason, if the bubbles are not large enough, specifically, not large enough to cover the entire surface of the filter, there is a problem that even if the suction operation is performed, the bubbles remain without passing through the filter.

  Such a problem exists not only in an ink jet recording head that ejects ink droplets but also in other liquid ejecting heads.

Japanese Patent Laid-Open No. 11-10904 (FIG. 1 etc.)

  In view of such circumstances, the present invention provides a liquid ejecting head and a liquid ejecting apparatus that can discharge liquid droplets well and can reliably discharge bubbles in the filter chamber during a suction operation. Let it be an issue.

A first aspect of the present invention that solves the above problems includes a head body having a plurality of nozzle openings for discharging droplets, a first member having a first supply path that communicates with the head body at one end side, A second member having a second supply path which communicates with the first supply path at one end side and communicates with the storage means for storing the liquid at the other end side; the first member and the second member; And a filter that is held in a deformable manner in accordance with a change in the flow rate of the liquid, and the filter is provided in a connection region between the first member and the second member. A first filter chamber provided in the first member and a second filter chamber provided in the second member, the filter chamber being disposed in a filter chamber having a larger inner diameter than the region. And consists of
In addition, the first filter chamber has an inner diameter that is wider toward the filter side, and a first and a second expanded portion having different inclination angles with respect to the joint surface between the first member and the second member. The liquid ejecting head is characterized in that the inclination angle of the first expansion portion located on the filter side is smaller than the inclination angle of the second expansion portion.
In the first aspect, it is possible to discharge the droplets well and to reliably discharge the bubbles in the filter chamber during the suction operation. More specifically, when ejecting droplets, the flow rate of the liquid in the filter chamber is relatively slow, so the filter does not deform. For this reason, the pressure applied to the ink and the bubbles in the filter chamber is relatively small, and only the liquid passes through the filter, and the ink droplets are favorably ejected from the nozzles. Further, when the flow velocity of the liquid is increased during the suction operation or the like, the filter is deformed and is substantially in close contact with the first expansion portion, thereby increasing the flow path resistance in the filter chamber. For this reason, the pressure applied to the ink and the bubbles in the filter chamber increases, and the bubbles together with the liquid pass through the filter and are discharged from the nozzle to the outside.

According to a second aspect of the present invention, the filter is provided so as to be deformed toward the first expanding portion by an increase in the flow rate of the liquid and to be restored to the original state with a subsequent decrease in the flow rate. In the liquid jet head according to the first aspect,
In the second aspect, since the bubbles are discharged from the nozzle only during the suction operation, the liquid droplets are always discharged well.

According to a third aspect of the present invention, in the liquid jet head according to any one of the first to third aspects, the filter is formed in a spherical shape having a convex shape on the second filter chamber side. .
In the third aspect, the filter is more reliably deformed to the first supply path side due to the increase in the flow velocity of the liquid.

According to a fourth aspect of the present invention, the filter is supported by a support member having a peripheral portion made of an elastic material, and the support member is held between the first member and the second member. The liquid ejecting head according to any one of the first to third aspects is characterized by the above.
In the fourth aspect, the filter is more reliably deformed to the first supply path side due to the increase in the flow velocity of the liquid.

According to a fifth aspect of the present invention, in the first to fourth aspects, the opening area of the second expanding section on the first expanding section side is 1/3 or less of the area of the filter. The liquid ejecting head according to any one of the embodiments is provided.
In the fifth aspect, the filter is deformed and is substantially in close contact with the first spreading portion, so that the liquid and bubbles in the second filter chamber pass through the filter more reliably.

According to a sixth aspect of the invention, there is provided a liquid ejecting apparatus including the liquid ejecting head according to any one of the first to fifth aspects.
In the sixth aspect, it is possible to realize a liquid ejecting apparatus having improved various characteristics such as reliability and durability.

Hereinafter, the present invention will be described based on embodiments.
(Embodiment 1)
FIG. 1 is a schematic perspective view of a liquid ejecting apparatus according to Embodiment 1 of the invention. As shown in FIG. 1, an ink jet recording apparatus 10 that is a liquid ejecting apparatus of the present embodiment has an ink jet recording head (hereinafter referred to as a recording head) 11 that ejects ink droplets from nozzles fixed to a carriage 12. The recording head 11 is detachably attachable to an ink cartridge 13 which is a storage unit storing a plurality of different color inks such as black (B), cyan (C), magenta (M), and yellow (Y). It is fixed.

  The carriage 12 on which the recording head 11 is mounted is provided on a carriage shaft 15 attached to the apparatus main body 14 so as to be movable in the axial direction. Then, the driving force of the driving motor 16 is transmitted to the carriage 12 via a plurality of gears and a timing belt 17 (not shown), so that the carriage 12 is moved along the carriage shaft 15. On the other hand, the apparatus main body 14 is provided with a platen 18 along the carriage shaft 15 so that a recording medium S such as paper fed by a paper feeding device (not shown) is conveyed on the platen 18. Yes.

  A cap member 19 that seals the surface (nozzle opening surface) of the recording head 11 on which ink droplets are ejected is located at a position corresponding to the home position of the carriage 12, that is, near one end of the carriage shaft 15. A capping device 20 is provided. By sealing the nozzle opening surface with the cap member 19, the ink in the vicinity of the nozzle opening is prevented from drying. The cap member 19 also functions as an ink receiver during the flushing operation. Further, the cap member 19 is connected to a suction device (not shown) constituted by a tube pump or the like. Then, at a predetermined timing, a suction operation (cleaning operation) for sucking the inside of the cap member 19 by this suction device is executed, thereby preventing the occurrence of ejection defects such as nozzle clogging and missing dots. In this suction operation, by increasing the flow rate of ink more than at the time of printing (ink discharging), ink with increased viscosity and bubbles accumulated in the filter portion described later are forcibly discharged from each nozzle. Yes.

  Here, the recording head according to the present embodiment will be described. 2 is an exploded perspective view of the recording head according to the present embodiment, and FIG. 3 is an assembled sectional view thereof. FIG. 4 is an enlarged cross-sectional view of the filter chamber portion.

  As shown in FIGS. 2 and 3, the cartridge case 21 constituting the recording head 11 has a cartridge mounting portion 22 to which the above-described ink cartridge 13 (FIG. 1) is mounted. On the bottom surface side of the cartridge case 21, a plurality of ink supply paths (first supply paths) 24 having one end opened to each cartridge mounting portion 22 and the other end opened to the head body 23 side having nozzles are formed. A tubular channel forming portion 25 is provided so as to protrude. A plurality of inks that are inserted into the ink cartridge 13 and flow the ink in the ink cartridge 13 to the ink supply path 24 in the upper surface side of the cartridge case 21, that is, in the opening portion of the ink supply path 24 of each cartridge mounting portion 22. A supply needle 26 is fixed via a filter 27 for removing bubbles and foreign matters in the ink.

  On the lower surface side of the cartridge case 21, there is further provided a head case 32 that holds a piezoelectric element unit 30 having a plurality of piezoelectric elements 29 and has a head body 23 fixed to an end surface opposite to the cartridge case 21. A seal member 33 and a circuit board 34 are sandwiched between the cartridge case 21 and the head case 32.

  The seal member 33 is sandwiched between the flow path forming portion 25 and the protruding portion 36 in which a plurality of ink introduction paths 35 provided in the head case 32 are opened, whereby the ink supply path 24 and the ink introduction path 35 are separated. The connecting portion is sealed to prevent ink leakage from the connecting portion. The circuit board 34 is for supplying a signal for driving the piezoelectric element 29, and a connector 37 for connecting an external wiring (not shown) is fixed to one end of the circuit board 34. . The circuit board 34 is provided with an insertion hole 39 through which a connection wiring 38 such as an FPC connected to the piezoelectric element 29 is inserted, and the circuit board 34 and the connection wiring 38 are connected via the insertion hole 39. Connected. Further, on both sides of the insertion hole 39, corresponding to each ink introduction path 35, a through hole 42 that engages with a protrusion 36 that opens each ink introduction path 35 is provided.

  Note that one side surface of the cartridge case 21, that is, the side surface on the side where the connector 37 of the circuit board 34 is disposed has an exposure port 43 through which the connector 37 of the circuit board 34 is exposed. An external wiring (not shown) is connected to the connector 37 through the connector.

  Further, the head case 32 fixed to the lower surface side of the cartridge case 21 via the circuit board 34 and the seal member 33 accommodates a piezoelectric element unit 30 (30A, 30B) having a plurality of piezoelectric elements 29 to accommodate the piezoelectric elements. A storage chamber 44 for positioning and fixing 29 is provided in parallel. For example, since the recording head 11 of this embodiment includes a piezoelectric element unit 30A for discharging black ink and a piezoelectric element unit 30B for discharging color ink, the head case 32 includes these piezoelectric elements. Two accommodation chambers 44 for accommodating the units 30A and 30B are provided side by side. A head main body 23 that discharges ink droplets from nozzles (not shown) is fixed to the lower surface side of the head case 32 by driving the piezoelectric element 29.

  In the recording head 11 according to this embodiment, the seal member 33, the circuit board 34, the head case 32, and the head main body 23 are stacked in this order on the lower surface side of the cartridge case 21, and the nozzles of the head main body 23 are exposed to the outside. The frame body 46 having the window portion 45 to be inserted is inserted and fixed to the cartridge case 21 with a screw 47.

  Here, each ink supply needle 26 as the second member fixed to the cartridge case 21 as the first member is connected to each ink supply path 24 of the cartridge case 21 as shown in FIG. An ink flow having a penetrating path (second supply path) 48 communicating therewith, and connecting the ink cartridge 13 and the head main body 23 by the penetrating path 48 of the ink supply needle 26 and the ink supply path 24 of the cartridge case 21. A road is constructed. In addition, a plurality of introduction holes 49 having a diameter of, for example, about 0.2 mm are formed at the distal end portion of the ink supply needle 26, and the through passage 48 (ink Ink is supplied into the flow path). The ink supply needle 26 has a flange portion 50 in the vicinity of the end portion on the cartridge case 21 side, and melts a fusion projection provided on a joint surface of the flange portion 50 with the cartridge case 21, that is, the It is fixed to the cartridge case 21 by sonic fusion.

  In addition, a filter chamber 51 having a larger inner diameter than other regions of the ink flow path is provided in a joining region between the ink supply needle 26 and the cartridge case 21. Specifically, the first filter chamber, which is a space having a larger inner diameter than the other regions, in the joining region of the cartridge case 21 with the ink supply needle 26, that is, in the connection region with the through passage 48 of the ink supply passage 24. 52 is provided. On the other hand, the ink supply needle 26 is also provided with a second filter chamber 53, which is a space having a larger inner diameter than other regions, in a connection region of the through passage 48 with the ink supply passage 24. A filter chamber 51 in which the filter 27 is accommodated is formed by the first filter chamber 52 of the cartridge case 21 and the second filter chamber 53 of the ink supply needle 26. The filter chamber 51 (the first and second filter chambers 52 and 53) has a through-passage 48 in order to increase the area of the filter 27 and minimize the resistance (pressure) when ink passes during printing. In addition, the inner diameter is wider than the ink supply path 24. For example, in the present embodiment, the first and second filter chambers 52 and 53 constituting the filter chamber 51 are each formed such that the inner diameter becomes wider toward the filter 27 side.

  Furthermore, in the present invention, the first filter chamber 52 formed on the downstream side of the filter 27 in the filter chamber 51, that is, in the cartridge case 21, is inclined with respect to the joint surface between the cartridge case 21 and the ink supply needle 26. The first and second expanding portions 54 and 55 are different from each other. That is, the first expanding portion 54 located on the filter 27 side has an inclination angle θ <b> 1 of the inner surface with respect to the joint surface of the cartridge case 21 and the ink supply needle 26 than the inclination angle θ <b> 2 of the second expanding portion 55. Is formed to be smaller. The inclination angle θ1 of the first expanding portion 54 may be appropriately determined according to the deformation amount of the filter 27 as described later, but is preferably relatively small.

  The filter 27 arranged in the filter chamber 51 is provided so as to be deformable in accordance with an increase in the ink flow rate in the filter chamber 51. That is, the filter 27 is deformable and is provided on the first filter chamber 52 side during the suction operation in which the initial shape is maintained without being deformed during printing at a relatively slow ink flow rate and the ink flow rate is greatly increased. The filter 27 substantially adheres to the inner surface of the first expanding portion 54 due to this deformation. The filter 27 is preferably provided so as to be completely in close contact with the inner surface of the first widened portion 54 due to deformation accompanying an increase in the ink flow velocity, but the first widened portion 54 of the filter 27 is not provided. What is necessary is just to be provided so that the area | region which opposes an inner surface may approach the inner surface of the 1st expansion part 54 to such an extent that it does not function substantially. The filter 27 is provided so as to self-recover to its original state as the ink flow rate decreases after being deformed according to the increase in the ink flow rate.

  For example, in the present embodiment, the filter 27 is formed by forming a plurality of minute holes in a thin metal plate, and is formed by molding, pressing, or the like a metal material, for example. Since the filter 27 is thin, as described above, the filter 27 can be deformed as the ink flow rate in the filter chamber 51 increases, and is restored to its original state by its own elastic force as the ink flow rate decreases. Self-healing. In particular, the filter 27 according to the present embodiment is formed in a spherical shape with a convex on the second filter chamber 53 side (upstream side). For this reason, the filter 27 tends to be in close contact with the surface of the first spreading portion 54 due to deformation accompanying an increase in the ink flow rate, and easily returns to the original state as the ink flow rate decreases. In addition, since the distance between the filter 27 and the first expanding portion 54 is usually wide, the ink flows smoothly during printing and ink droplets are discharged well. The material, thickness, and the like of the filter 27 are not particularly limited. Considering the relationship with the inclination angle θ1 of the first expansion portion 54, that is, the filter 27 increases as the ink flow rate increases. It may be determined as appropriate so that it substantially adheres to the inner surface of the first expanded portion 54 when deformed.

  In such a configuration, the pressure (flow path resistance) applied to the ink in the filter chamber 51 does not substantially increase at the time of printing, and ink droplets can be discharged well, and at the time of suction operation, the filter chamber 51 The flow path resistance (pressure) in the inside increases greatly, and the bubbles in the second filter chamber 53 surely pass through the filter 27.

  Specifically, at the time of printing, since the flow rate of ink in the filter chamber 51 (second filter chamber 53) is relatively slow, as shown in FIG. The state is maintained. In other words, the filter 27 needs to have a rigidity that does not deform at the ink flow rate during printing. If the filter 27 is maintained in the initial state as described above, a predetermined space is secured between the filter 27, the first expanded portion 54, and the inner surface, so that the entire surface of the filter 27 serves as a flow path. Function. Therefore, the flow path resistance in the filter chamber 51 does not increase, and the ink droplets are favorably ejected from the nozzles of the head body 23 by driving the piezoelectric element 29.

  On the other hand, when the above-described suction operation is performed to discharge the air bubbles accumulated in the second filter chamber 53, the flow velocity in the filter chamber 51 is greatly increased as compared with printing. That is, a pressure difference is generated between the second filter chamber 53 on the upstream side of the filter 27 and the first filter chamber 52 on the downstream side. Therefore, during the suction operation, as shown in FIG. 4B, the filter 27 is elastically deformed by receiving pressure as the ink flow rate increases, and substantially adheres to the inner surface of the first expanding portion 54. . Thus, the filter 27 is brought into close contact with the inner surface of the first expanding portion 54, so that the area of the filter 27 is substantially reduced. That is, only the region corresponding to the second expanded portion 55 of the filter 27 functions as an ink flow path. For this reason, during the suction operation, the pressure applied to the ink and the bubbles in the second filter chamber 53 is significantly increased as compared with the printing. Thereby, the air bubbles accumulated in the second filter chamber 53 surely pass through the filter 27 together with the ink. For example, even when the size of the bubbles accumulated in the second filter chamber 53 is relatively small, the bubbles surely pass through the filter 27 by the suction operation. Thereby, the bubbles accumulated in the second filter chamber 53 are surely discharged to the outside from the nozzles of the head body 23 by the suction operation. Thereafter, when the suction operation is finished and the pressure difference between the second filter chamber 53 and the first filter chamber 52 becomes small, the filter 27 is self-recovered to its original state by its own elastic force.

  The opening area of the second expanding section 55 on the first expanding section 54 side is preferably 1/3 or less of the area of the filter 27 (the area exposed in the ink flow path). Thereby, the pressure applied to the ink and the bubbles in the second filter chamber 53 can be sufficiently increased by the suction operation, and the bubbles can be discharged to the outside more reliably.

(Embodiment 2)
FIG. 5 is a cross-sectional view illustrating a main part of the recording head according to the second embodiment. The present embodiment is an example in which the filter holding structure is changed. Specifically, as shown in FIG. 5, in this embodiment, the peripheral portion of the filter 27 is supported by a support member 56 made of a material that can be deformed with an increase in the ink flow rate, for example, an elastic material. Except that the support member 56 is sandwiched between the cartridge case 21 and the ink supply needle 26, it is the same as in the first embodiment.

  According to such a configuration, the filter 27 can be more reliably deformed by the support member 56 being deformed as the ink flow rate is increased during the suction operation. Therefore, as described above, air bubbles upstream of the filter 27 (in the second filter chamber 53) can be more reliably discharged to the outside by the suction operation. In the case of such a configuration, the filter 27 may be formed in a substantially spherical shape as in the first embodiment, but of course may be formed in a substantially flat shape. Even when the filter 27 is formed to be substantially flat, the deformation amount of the support member 56 is large, so that the filter 27 substantially adheres to the inner surface of the first expanding portion 54.

(Other embodiments)
As mentioned above, although it demonstrated in detail based on embodiment of this invention, of course, this invention is not limited to embodiment mentioned above. In the above-described embodiment, the cartridge case is exemplified as the first member having the first supply path (ink supply path), and the ink is used as the second member having the second supply path (penetration path). Although the supply needle has been illustrated, it goes without saying that the first member and the second member are not limited to these illustrated members.

  In the above-described embodiment, the ink jet recording head is exemplified as the liquid ejecting head of the present invention. However, the basic configuration of the liquid ejecting head is not limited to the above. The present invention is intended for a wide range of liquid ejecting heads, for example, various recording heads used in image recording apparatuses such as printers, color material ejecting heads used in the manufacture of color filters such as liquid crystal displays, The present invention can also be applied to electrode material ejecting heads used for forming electrodes such as organic EL displays and FEDs (surface emitting displays), bioorganic matter ejecting heads used for biochip manufacturing, and the like.

1 is a schematic perspective view of a recording apparatus according to Embodiment 1. FIG. FIG. 3 is an exploded perspective view of the recording head according to the first embodiment. FIG. 3 is an assembled cross-sectional view of the recording head according to the first embodiment. FIG. 3 is an enlarged cross-sectional view of a filter chamber portion of the recording head according to the first embodiment. 6 is an enlarged cross-sectional view of a filter chamber portion of a recording head according to Embodiment 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet recording device, 11 Recording head, 21 Cartridge case, 24 Ink supply path, 26 Ink supply needle, 27 Filter, 48 Through path, 49 Introduction hole, 50 Flange part, 51 Filter chamber, 52 1st filter chamber, 53 2nd filter chamber, 54 1st expansion part, 55 2nd expansion part, 56 Support member

Claims (6)

A head main body having a plurality of nozzle openings for discharging droplets, a first member having a first supply path communicating with the head main body at one end side, one end side communicating with the first supply path, and a liquid With a change in the flow rate of the liquid provided between the first member and the second member, a second member having a second supply path in which the other end side communicates with the storing means to be stored And a filter held in a deformable manner,
The filter is provided in a connection region between the first member and the second member and is disposed in a filter chamber having a wider inner diameter than other regions, and the filter chamber is disposed in the first region. A first filter chamber provided in the member and a second filter chamber provided in the second member;
In addition, the first filter chamber has an inner diameter that is wider toward the filter side, and a first and a second expanded portion having different inclination angles with respect to the joint surface between the first member and the second member. The liquid ejecting head, wherein the inclination angle of the first expansion portion located on the filter side is smaller than the inclination angle of the second expansion portion. 2. The filter according to claim 1, wherein the filter is provided so as to be deformed toward the first expansion portion with an increase in the flow velocity of the liquid and to be restored to the original state with a subsequent decrease in the flow velocity. The liquid jet head described in 1. The liquid ejecting head according to claim 1, wherein the filter is formed in a spherical shape in which the second filter chamber side is convex. The filter is supported by a support member made of an elastic material at a peripheral portion thereof, and the support member is held between the first member and the second member. The liquid jet head according to any one of the above. 5. The liquid jet according to claim 1, wherein an opening area of the second expanding portion on the first expanding portion side is 1/3 or less of an area of the filter. head. A liquid ejecting apparatus comprising the liquid ejecting head according to claim 1.

Images