Patent Publication Number: US-8967779-B2

Title: Flow channel member, liquid ejecting head, liquid ejecting apparatus, and liquid reservoir

Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to a flow channel member, a liquid ejecting head, a liquid ejecting apparatus incorporating the liquid ejecting head, and a liquid reservoir mountable on the flow channel member, and particularly relates to a technique efficiently applicable to a flow channel member, a liquid ejecting head, and a liquid ejecting apparatus, having a sealing member for maintaining liquid tightness between the flow channel member and a liquid reservoir removably mounted on the flow channel member. 
     2. Related Art 
     A typical liquid ejecting head for discharging liquid droplets includes an ink jet recording head for discharging ink droplets. For example, JP-A-2007-015272 has proposed, for example, an ink jet recording head having a head body for discharging ink droplets from a nozzle port, and a channel member, to which a head body is secured and to which an ink cartridge (a liquid reservoir) for storing the ink is removably arranged, for supplying the ink from the ink cartridge to the head body. 
     According to JP-A-2007-015272, a supply section composed of a pressing portion formed of a porous material or the like is arranged on an ink cartridge and pressed against a filter arranged in an installation section of a flow channel member, thereby interconnecting the ink cartridge and the flow channel member. In this case, it is necessary to prevent water in ink from evaporating and to prevent thickening of the ink, which in turn affects ink discharge. To this end, an enclosed space is formed in the periphery of the supply section of the ink cartridge and the filter. That is, an annular sealing member is disposed in the periphery of the installation section including an opening having the filter disposed therein, and the lower end face of a leg portion annularly projecting from the ink cartridge abuts a top plane portion of the sealing member, whereby predetermined liquid tightness is maintained. 
     According to the sealing member disclosed in JP-A-2007-015272, an inner leg portion adjacent to the installation section and an outer leg portion located away from the installation section project from the both edges of the top plane portion in the direction away from the ink cartridge to make a concave cross-sectional shape. Connecting portions between the top plane portion and the inner leg portion and between the top plane portion and the outer leg portion make a right angle. 
     In JP-A-2007-015272, as described above, since the connecting portions of the top plane portion to the inner leg portion and the outer leg portion of the sealing member make a right angle, repeated attaching and detaching of an ink cartridge causes the stress from the pressing load acting on the top plane portion of the sealing member via the leg portions of the ink cartridge to be concentrated on the connecting portions thereby causing the top plane portion to sag downward, thereby decreasing the adhesion with the ink cartridge. 
     Thickening the sealing member improves such creep resistance; however, it adversely increases the reaction force acting from the sealing member on the ink cartridge. Therefore, it has a limitation in this respect. 
     Further, these problems exist not only in the flow channel member used in the liquid ejecting head such as the ink jet recording head, but also in flow channel members used in devices other than a liquid ejecting head. 
     SUMMARY 
     An advantage of some aspects of the invention is that it provides a flow channel member, a liquid ejecting head, and a liquid ejecting apparatus having a sealing member having improved creep resistance and sealing performance due to uniformly distributing stress. 
     An aspect of the invention provides a flow channel member disposed between a liquid reservoir for storing a liquid therein and a head body for ejecting the liquid, the flow channel member including: a flow channel member main body having a liquid flow channel, through which a liquid flows from the liquid reservoir via one port into the head body via another port and having an installation section for mounting the liquid reservoir constituted by the periphery of the one port; and a sealing member made of an elastic material, arranged around the entire periphery of the installation section of the flow channel member main body. The sealing member is integrally formed of: a top plane portion, where an end face of an annular leg portion of the liquid reservoir abuts the top plane portion so as to define an enclosed space between an inner peripheral surface of the leg portion and an outer peripheral surface of the installation section; and an inner leg portion adjacent to the installation section and an outer leg portion away from the installation section, extending from an inner edge and an outer edge of the top plane portion, respectively, along the longitudinal axis of the installation section in a direction away from the enclosed space, and each having a face abutting the flow channel member main body. Furthermore, at least a portion of the sealing member has a thicker portion formed so that the thickness of the at least inner leg portion increases gradually from the end face of the inner leg portion toward the top plane portion so that the distance between the inner peripheral surface of the inner leg portion and the inner peripheral surface of the outer leg portion decreases gradually. 
     According to the aspect of the invention, at least a portion of the inner leg portion has a thicker portion to distribute stress acting thereon via the top plane portion. As a result, the creep resistance of the sealing member may be improved, and the adhesion of the outer peripheral surface of the inner leg portion with respect to the outer peripheral surface of the installation member may be stably maintained over the long term. In addition, the amount of liquid leakage from the enclosed space may also be minimized. 
     It is desirable that the inner peripheral surface of the thicker portion of the sealing member be formed into a curved surface. With such a structure, the stress acting on the sealing member may be efficiently distributed. In addition, it is desirable that the sealing member be formed so that the leg portion of the liquid reservoir is arranged on the flow channel member so as to abut the top plane portion at a position offset from the center of the width of the top plane portion toward the outer leg portion, when the liquid reservoir is mounted on the flow channel member. Therefore, the width of the top plane portion of the sealing member may be reduced without decreasing the sealing performance. 
     Furthermore, it is desirable that the end faces of the outer leg portion and the inner leg portion of the sealing member be curved. In this case, even if the inner leg portion and the outer leg portion of the sealing member are arranged obliquely with respect to the flow channel member main body, the gap between the end faces of the inner leg portion and the outer leg portion and the flow channel member main body may be removed to maintain satisfactory seal performance. 
     In addition, another aspect of the invention provides a liquid ejecting head including the flow channel member. 
     According to the aspect, stable sealing performance between the liquid reservoir and the flow channel member is achieved over the long term with the result that the discharge property of liquid droplets may be maintained properly. 
     Furthermore, another aspect of the invention provides a liquid ejecting apparatus including the liquid ejecting head. 
     According to the aspect, a more reliable and compact liquid ejecting apparatus may be achieved. 
     Furthermore, another aspect of the invention provides a liquid ejecting apparatus including the flow channel member. 
     According to the aspect, a more reliable and compact liquid ejecting apparatus may be achieved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is an exploded perspective view of a recording head according to an embodiment. 
         FIGS. 2A to 2C  are sectional views of the recording head according to the embodiment. 
         FIGS. 3A and 3B  are perspective views of a sealing member of the embodiment. 
         FIGS. 4A and 4B  are sectional views illustrating a procedure for mounting an ink cartridge on a flow channel member. 
         FIGS. 5A and 5B  are sectional views illustrating the procedure for mounting the ink cartridge on the flow channel member. 
         FIG. 6  is a schematic view of a recording apparatus according to an embodiment of the invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Embodiments of the invention will now be described in detail with reference to the accompanying drawings. 
       FIG. 1  is an exploded perspective view of an ink jet recording head of a liquid ejecting head according to an embodiment of the invention.  FIGS. 2A to 2C  are sectional views of the recording head with an ink cartridge, i.e., a liquid reservoir for storing a liquid ink that has been mounted on a flow channel member. 
     As shown in  FIGS. 1 and 2A  to  2 C, an ink jet recording head  10  is provided with a flow channel member  30  having ink cartridges  20 , i.e., liquid reservoirs for storing ink that can be attached to or detached from the flow channel member  30 , and a head body  40  secured to the flow channel member  30 . 
     The flow channel member  30  is provided with a flow channel member main body  310 , a filter  317 , and a sealing member  330  arranged in the flow channel member main body  310 . A liquid flow channel  311  is formed in the flow channel member main body  310 . Through the liquid flow channel  311 , the ink flows via a filter chamber  311 A, i.e., one opening of the channel  311 , from the ink cartridge  20  into the head body  40  via the other opening  311 B. The filter chamber  311 A is formed into a cone-shaped space with its diameter increasing gradually toward the open end. A cartridge mounting section  312  for mounting the ink cartridge  20  is arranged adjacent to the filter chamber  311 A of the liquid flow channel  311 . 
     In the case of the embodiment, four ink cartridges are mounted on the cartridge mounting section  312 . In addition, the periphery of the cartridge mounting section  312  is surrounded by a wall portion  313 , and first engagement holes  314  are arranged so as to penetrate the thickness of one of a pair of opposing walls of the wall portion  313 . In addition, second engagement holes  315  are arranged to penetrate the thickness of another wall opposing the wall including the first engagement holes  314 . A first engagement claw  24  and a second engagement claw  25  of the ink cartridge  20  are engaged with the first engagement hole  314  and the second engagement hole  315 , respectively, whereby the ink cartridge  20  is mounted on the cartridge mounting section  312 . 
     According to the embodiment, in order to mount the four ink cartridges  20  on the cartridge mounting section  312 , partition plates  313 A are arranged between the ink cartridges  20  so as to divide the cartridge mounting section  312 . 
     In addition, cylindrically projecting installation sections  316  are arranged in the cartridge mounting section  312  of the flow channel member main body  310 . According to the embodiment, in order to secure the four ink cartridges to the cartridge mounting section  312 , similarly four installation sections  316  are arranged. Each of the installation sections  316  according to the embodiment has the shape of a cylinder having the liquid flow channel  311  opening at its tip surface. The filter  317  for covering a port of the liquid flow channel  311  is arranged on the tip surface at which the liquid flow channel  311  opens. The installation section  316  forms a portion of the liquid flow channel  311 , and the filter  317  is disposed to cover the filter chamber  311 A at its tip portion. The filter  317  is intended to remove foreign substances and bubbles contained in the liquid ink, and has the shape of a disk whose area is substantially the same as that of the tip surface of the installation section  316  (the filter chamber  311 A of the liquid flow channel  311 ). The circumference of the filter  317  is arranged at substantially the same position as the circumference of the installation section  316 . In addition, an annular sealing groove  319  is arranged around the periphery of the installation section  316  on which the filter  317  is arranged, and a sealing member  330  is disposed in the sealing groove  319 . 
     In particular as shown in  FIGS. 2B and 2C  in enlarged dimensions, the sealing member  330  according to the embodiment is integrally formed of a top plane portion  330 A, an inner leg portion  330 B, and an outer leg portion  330 C, and has a generally concave cross section. Abutment of the end face of an annular leg portion  21 A of the ink cartridge  20  to the top plane portion  330 A defines an enclosed space  336  between the inner peripheral surface of the leg portion  21 A and the outer peripheral surface of the installation section  316 . The inner leg portion  330 B extends from one edge of the top plane portion  330 A along the longitudinal axis of the installation section  316  in a direction away from the enclosed space  336  (downward in  FIGS. 2A to 2C ), and abuts at the lower end face thereof the flow channel member main body  310  in the sealing groove  319 . In addition, the outer leg portion  330 C extends from the other edge of the top plane portion  330 A along the longitudinal axis of the installation section  316  in the direction away from the enclosed space  336  (downward in  FIGS. 2A to 2C ), and abuts at the lower end face thereof the flow channel member main body  310  in the sealing groove  319 . Thus, when the ink cartridge  20  is mounted on the flow channel member  30 , the enclosed space  336  is liquid-tightly formed by the sealing member  330 . 
     Furthermore, in a joint portion of the inner leg portion  330 B and the top plane portion  330 A and a joint portion of the outer leg portion  330 C and the top plane portion  330 A, a portion from the inner peripheral surface of the inner leg portion  330 B to the inner peripheral surface of the top plane portion  330 A, and a portion from the inner peripheral surface of the outer leg portion  330 C to the inner peripheral surface of the top plane portion  330 A are formed in a curved surface, thereby forming thicker portions  330 D and  330 E, respectively. 
     According to the embodiment, when the ink cartridge is mounted on the flow channel member  30 , the point at which a pressing load is applied on the top plane portion  330 A via the leg portion  21 A of the ink cartridge  20  is located at the position P offset from the center of the width of the top plane portion  330 A toward the outer leg portion  330 C, as shown in  FIG. 2C . Therefore, it is possible to form the compact sealing member  330  having the narrower width of the top plane portion  330 A. 
     The curve radius of the curved surface constituted by the inner peripheral surface of the inner leg portion  330 B and the inner peripheral surface of the top plane portion  330 A is equal to, for example, a distance φ 1  from an innermost point of an end face  330 F of the inner leg portion  330 B to the intersection of a horizontal line through the innermost point and the normal through the position P, and the curve radius of the curved surface constituted by the inner peripheral surface of the outer leg portion  330 C and the inner peripheral surface of the top plane portion  330 A is equal to, for example, a distance φ 2  from an innermost point of an end face  330 G of the outer leg portion  330 C to the intersection of a horizontal line through the innermost point and the normal through the position P, whereby, the thicker portions  330 D and  330 E may be formed to satisfactorily distribute the stress to prevent stress concentration. 
     Furthermore, the end face  330 F of the inner leg portion  330 B and the end face  330 G of the outer leg portion  330 C are curved. As a result, even if the inner leg portion  330 B and the outer leg portion  330 C of the sealing member  330  are arranged obliquely with respect to the flow channel member main body  310 , the gap between the end faces of the inner leg portion  330 B and the outer leg portion  330 C and the flow channel member main body  310  may be removed to maintain satisfactory seal performance. 
     The entire shape of the sealing member  330  will be described in detail with reference to  FIGS. 3A and 3B .  FIGS. 3A and 3B  are perspective views illustrating the entire sealing member. As shown in  FIGS. 3A and 3B , the sealing member  330  is made of a flexible material such as rubber or elastomer, and integrally formed from the flat top plane portion  330 A, the cylindrical inner leg portion  330 B, and the cylindrical outer leg portion  330 C having an inner diameter larger than the inner leg portion  330 B. 
     The inner leg portion  330 B has an inner diameter so that it may come into close contact with the circumference of the installation section  316 . In addition, the outer leg portion  330 C has an outer diameter somewhat smaller than the sealing groove  319  arranged around the periphery of the installation section  316 . The sealing member  330  is arranged so as to fit into the periphery of the installation section  316 . Since the top plane portion  330 A is supported by the upper end of the inner leg portion  330 B (the end closer to the ink cartridge  20 ) and the upper end of the outer leg portion  330 C, load from the ink cartridge  20  causes the top plane portion  330 A to easily sag between the inner leg portion  330 B and the outer leg portion  330 C so as to be convex downward toward the flow channel member main body  310 . 
     The ink cartridge  20  has the shape of a hollow box for storing an ink (liquid) therein as shown in  FIGS. 1 and 2A . In addition, at the bottom of the ink cartridge  20 , a cylindrical rib  21  is arranged, and in the inner side of rib  21 , a supply port  22  is arranged for supplying the ink in the ink cartridge  20  to the flow channel member  30 . A supply section  23  is arranged in the inner side of the supply port  22 . The supply section  23  is provided to press against the filter  317  of the flow channel member  30  to supply the ink in the ink cartridge  20  to the liquid flow channel  311  of the flow channel member  30 . The supply section  23  may include, for example, a porous material or a nonwoven fabric such as cotton-like pulp, water-absorbent polymer, and urethane foam. The leg portion  21 A, i.e., an annular protrusion, abutting the top plane portion  330 A of the sealing member  330  is arranged so as to protrude from the lower end face of the rib  21 . 
     The head body  40  has, on the side opposite from the flow channel member  30 , a liquid ejecting surface including a nozzle discharging liquid ink droplets. In addition, the interior (not shown) of the head body  40  contains a liquid flow channel with which both of the nozzle and the channel in the flow channel member  30  communicate, and a pressure generator causing a change in the pressure of the ink in the liquid flow channel, and so forth. The pressure generator may be, for example, a device for discharging ink droplets from a nozzle by deformation of a piezoelectric actuator having a piezoelectric material exhibiting an electromechanical transducer function to cause a change in the volume of the liquid flow channel, thereby causing a change in the pressure of the ink in the liquid flow channel, a device for discharging ink droplets from a nozzle by forming bubbles generated by heat from a heater element arranged in the liquid flow channel, a device, so-called electrostatic actuator, for discharging ink droplets from a nozzle by generating electrostatic force between a diaphragm and an electrode to transform the diaphragm, and so forth. 
     According to the ink jet recording head  10 , the ink from the ink cartridge  20  is supplied via the flow channel member  30  to the head body  40 , in which a pressure generator causes a change in the pressure of the ink in the liquid flow channel, thereby discharging the ink droplets from a nozzle. 
     A method for mounting the ink cartridge  20 , which has been removed from the flow channel member  30 , on the flow channel member  30  will now be described with reference to  FIGS. 4A and 4B  and  FIGS. 5A and 5B .  FIGS. 4A to 5B  are sectional views illustrating a procedure for mounting the ink cartridge according to the embodiment to the flow channel member. 
     As shown in  FIG. 4A , the ink cartridge  20  has been removed from the flow channel member  30 . The ink cartridge  20  is inserted obliquely, the first engagement claw  24  first, into the interior of the wall portion  313  of the flow channel member main body  310 , as shown in  FIG. 4B , and then the first engagement claw  24  is inserted into the first engagement hole  314 . Therefore, the rib  21  of the ink cartridge  20  abuts the portion of the sealing member  330  close to the first engagement hole  314 . 
     As shown in  FIG. 5A , when the first engagement claw of the ink cartridge  20  is inserted into the first engagement hole  314 , the ink cartridge  20  rotates around the first engagement claw  24  serving as a fulcrum to cause the ink cartridge  20  to be inserted into the inside of the wall portion  313 . The second engagement claw  25  is then pressed by the wall portion  313  of the flow channel member main body  310  to become elastically deformed so that it does not disturb insertion of the ink cartridge  20  into the inside of the wall portion  313 . 
     In addition, according to the embodiment, the ink cartridge  20  has the second engagement claw  25  inserted into the second engagement hole  315 , and then the ink cartridge is pressed further into the inside of the wall portion  313 , i.e., toward the side facing the head body  40 . Therefore, the rib  21  of the ink cartridge  20  causes the sealing member  330  to sag down so as to be convex downward toward the flow channel member main body  310 . As a result, the inner side of the rib  21  is sealed. 
     In such a case, release of pressing force from the ink cartridge  20  moves the ink cartridge  20  away from the installation section  316  by the reaction force (elastic force) from the sealing member  330 , as shown in  FIG. 5B . Then, the second engagement claw  25  which has been elastically transformed by the pressing force by the wall portion  313  of the flow channel member main body  310  is inserted into the second engagement hole  315  by the restoring elastic force. Then, the reaction force of the sealing member  330  and the elastic force of the second engagement claw  25  cause the second engagement claw  25  to abut the wall portion  313  including the second engagement hole  315  away from the installation section  316  so that the ink cartridge  20  is secured to the cartridge mounting section  312  of the flow channel member  30 . 
     For the sealing member  330  according to the embodiment, the thicker portion  330 D of the inner leg portion  330 B distributes the stress from the ink cartridge  20  via the top plane portion  330 A (see  FIGS. 2A to 2C ). As a result, creep resistance of the sealing member  330  may be improved, and the adhesion of the outer peripheral surface of the inner leg portion  330 B with respect to the outer peripheral surface of the installation section  316  may be stably maintained over the long term. In addition, the amount of liquid leakage from the enclosed space  336  may also be minimized. 
     The inner peripheral surface of the thicker portion  330 D is curved to efficiently perform particularly satisfactory distribution of the stress acting on the sealing member  330 . 
     Having described the embodiment of the invention hereinbefore, the basic configuration of the invention is not limited to the above-described configuration. For example, in the embodiments, a curved surface, i.e., the thicker portion  330 D makes up a part of the inner peripheral surface of the inner leg portion  330 B, and further a curved surface, i.e., the thicker portion  330 E makes up a part of the inner peripheral surface of the outer leg portion  330 C, however, only the thicker portion  330 D may be formed in the inner leg portion  330 B. This is because, due to contact of the outer peripheral surface of the inner leg portion  330 B and the outer peripheral surface of the installation section  316 , sealing performance between them significantly affects particularly the lifetime of the sealing member  330 . 
     In addition, the thicker portion is not necessarily formed into a curved surface. A curved surface performs the best stress distribution, but at least the inner leg portion  330 B needs to be formed so that the thickness thereof increases gradually from the end face  330 F of the inner leg portion  330 B toward the inner peripheral surface of the top plane portion  330 A and the distance between the inner peripheral surface of the inner leg portion  330 B and the inner peripheral surface of the outer leg portion  330 C decreases gradually. Therefore, the inner leg portion  330 B may be formed into a linear shape, such as a tapered shape. Furthermore, the end faces  330 F and  330 G are also not necessarily formed into curved surfaces. However, even if the sealing member  330  is arranged obliquely with respect to the flow channel member main body  310 , the sealing performance may be improved. 
     In addition, the ink jet recording head  10  according to the embodiment forms a portion of the ink jet recording head unit having the ink channel communicating the ink cartridge or the like to be incorporated in the ink jet recording apparatus.  FIG. 6  is a schematic view illustrating an example of the ink jet recording apparatus. 
     According to an ink jet recording apparatus I shown in  FIG. 6 , ink cartridges  20  constituting an ink supply device are removably arranged in an ink jet recording head  10 , and a carriage  3  incorporating the ink jet recording head  10  is movably arranged along the axis of the carriage shaft  5  on an apparatus body  4 . The ink jet recording head  10 , for example, may discharge a black ink composition and a color ink composition. 
     Then, driving power from a drive motor  6  is transmitted via a plurality of gears (not shown) and a timing belt  7  to the carriage  3  so that the carriage  3  incorporating the ink jet recording head  10  moves along the carriage shaft  5 . The apparatus body  4  has a platen  8  along the carriage shaft  5 , and recording sheets S, i.e., recording media such as paper sheets or the like fed by a paper feeding roller (not shown) or the like are transported on the platen  8 . 
     According to the embodiments, the ink jet recording head  10  having the flow channel member  30  has been described; however, the invention is also applicable to an ink jet recording apparatus having the flow channel member  30  in a position other than the ink jet recording head  10 . In particular, if the ink jet recording apparatus includes an ink tank, i.e., a liquid reservoir for storing an ink therein which is not incorporated in the carriage  3  but secured to the apparatus body  4 , and a tubular supply pipe interconnecting the ink tank and the head body  40 , for example, the flow channel member  30  described above may be arranged in the place where the ink tank is provided. 
     In addition, the ink jet recording apparatus I is, but is not limited to, an apparatus having the ink jet recording head  10  incorporated in the carriage  3  that moves in a main scanning direction, and for example, the invention is also applicable to a so-called line recording apparatus performing printing simply by moving a recording sheet S such as paper in a vertical scanning direction with the ink jet recording head  10  secured in position. 
     Furthermore, the invention is generally targeted for a liquid ejecting head, and is also applicable to a method for manufacturing, for example, a recording head among various ink jet recording heads or the like used for an image recording apparatus of a printer or the like, a color material ejecting head used for manufacturing a color filter of a liquid crystal display or the like, an electrode material ejecting head used for forming an electrode of an organic EL display, a field emission display (FED) or the like, a living organic material ejecting head used for manufacturing a biochip, or the like. 
     In addition, the invention is not limited to a flow channel member incorporated in a liquid ejecting head and a liquid ejecting apparatus, and may be applicable to flow channel members incorporated in other devices. 
     The entire disclosure of Japanese Patent Application No. 2012-189627, filed Aug. 30, 2012 is incorporated by reference herein.