JP5776454B2 - Droplet ejector - Google Patents

Description

  The present invention relates to a droplet ejecting apparatus that ejects droplets.

  2. Description of the Related Art Conventionally, some droplet ejecting apparatuses include a head unit having a configuration in which a plurality of heads each having a droplet ejecting nozzle are arranged in a plane and integrated.

  Patent Document 1 discloses an ink jet printer head unit having the above-described configuration. The head unit of Patent Document 1 has a configuration in which a plurality of heads are integrated by being respectively attached to a head holding member (base plate), and the plurality of heads are arranged in a plane. The head unit is fixed to the printer body by ejecting ink droplets from the nozzles of the plurality of heads onto the recording medium transported to the head unit. A desired image is recorded on a recording medium.

JP 2010-201790 A

  By the way, in a liquid droplet ejecting apparatus such as an ink jet printer, if foreign matter or bubbles are mixed in the liquid in the head or the liquid in the nozzle is dried (thickened), the liquid droplet ejection from the nozzle becomes abnormal. It is well known. For this purpose, the above-described droplet ejecting apparatus generally includes a configuration (maintenance member) for maintaining or recovering the ejection performance of the head (hereinafter also referred to as maintenance). For example, for the purpose of preventing the liquid in the nozzle from drying, or for the purpose of sucking and discharging foreign matter and air bubbles mixed in the liquid, and the liquid in which the viscosity has increased in the nozzle, the nozzles of the head are opened. A cap member or the like that covers the liquid droplet ejection surface corresponds to the maintenance member.

  In this regard, as described above, the head unit of Patent Document 1 has a configuration in which a plurality of planarly arranged heads are held by a head holding member, and the maintenance member performs head maintenance. When pressed against the unit, the maintenance member comes into contact with the head holding member, and an impact (pressing force) acts on the head holding member. At this time, if the head holding member is deformed by the applied impact, the positional relationship between the plurality of heads may be shifted. That is, the positional relationship of the nozzles between the plurality of heads is shifted, and this leads to a decrease in print quality in the case of an ink jet printer such as that disclosed in Patent Document 1.

  An object of the present invention is to provide a liquid droplet ejecting apparatus that can mitigate an impact when a maintenance member is pressed against a head unit and can suppress deformation of a head holding member that holds a plurality of liquid droplet ejecting heads. Is to provide.

According to a first aspect of the present invention, there is provided a liquid droplet ejecting apparatus comprising: a head unit having a plurality of liquid droplet ejecting heads having nozzles for ejecting liquid droplets; and a head holding member that holds the plurality of liquid droplet ejecting heads; A maintenance member that is pressed against the unit from the nozzle opening side to maintain or restore the ejection performance of the plurality of droplet ejection heads, and is provided at a position closer to the nozzle opening than the head holding member. A cushioning member that contacts the maintenance member when pressed against the head unit and reduces an impact transmitted from the maintenance member to the head holding member, and the maintenance member is formed on an outer peripheral portion thereof. A cap member having a lip portion, wherein the lip portion of the cap member abuts against the buffer member, It is configured so that the nozzle of the droplet ejecting head is covered with the cap member, wherein the cushioning member is disposed in a state where between air is present between the portion and the front SL head holding member at least the lip portion is in contact And having a rigidity lowering portion that locally lowers the rigidity of the contact portion with the lip portion or the peripheral portion thereof .

  In the present invention, since the buffer member is disposed on the nozzle opening side surface of the head holding member that holds the plurality of liquid droplet ejection heads, the maintenance member performs the head ejection performance maintenance or recovery operation (maintenance). In this case, the maintenance member is in contact with the buffer member, and is not in direct contact with the head holding member. In addition, a space (gap) exists between the portion of the buffer member that contacts the maintenance member and the head holding member. With these configurations, when the maintenance member is pressed against the head unit, the shock-absorbing member is deformed, so that the impact (pressing force) at that time is alleviated, so that the deformation of the head holding member is suppressed.

According to a second aspect of the invention, a liquid droplet ejecting apparatus includes: a head unit having a plurality of liquid droplet ejecting heads having nozzles for ejecting liquid droplets; and a head holding member that holds the plurality of liquid droplet ejecting heads; A maintenance member that is pressed against the unit from the nozzle opening side to maintain or restore the ejection performance of the plurality of droplet ejection heads, and is provided at a position closer to the nozzle opening than the head holding member. A buffer member that contacts the maintenance member when pressed against the head unit and reduces an impact transmitted from the maintenance member to the head holding member, and the plurality of liquid droplet ejecting heads are disposed on the nozzle. has with channel portion communicating are formed respectively, the number of multi held by the head holding member of the flow channel structure, respectively, said buffer The material is a nozzle plate that is common to the plurality of droplet ejecting heads, and has a plurality of nozzle forming portions in which the nozzles of the plurality of droplet ejecting heads are respectively formed, and the nozzle formation of one of the nozzle plates One of the liquid droplet ejecting heads is configured by joining one flow path structure to a portion , and the maintenance member is a cap member having a lip portion formed on an outer peripheral portion thereof. The cap member is configured such that the lip portion of the cap member is in contact with a portion outside the plurality of nozzle forming portions of the nozzle plate so that the nozzles of the plurality of droplet ejecting heads are covered with the cap member, The nozzle plate is arranged in a state where there is a space between at least the portion where the lip portion contacts and the head holding member. In addition, the rigidity of the contact portion with the lip portion or the peripheral portion thereof is locally reduced, and the impact when the cap member comes into contact is a joint portion between the flow path structure and the nozzle forming portion. suppresses transmitted it to, and is characterized in Rukoto to have a rigidity reduction portion.

  In the present invention, the nozzle plate has a plurality of nozzle formation portions each having a plurality of droplet ejection head nozzles formed therein, and the plurality of nozzle formation portions are joined to the plurality of flow path structures. This is a nozzle plate common to the droplet ejecting head. And the surface on the opposite side to the surface joined to a flow-path structure of a some nozzle formation part turns into a droplet ejection surface where a nozzle opens toward the exterior. Of course, this nozzle plate is positioned closer to the nozzle opening than the head holding member that holds the plurality of flow channel structures, and the portion other than the nozzle forming portion joined to the flow channel structure is the head holding member. By disposing the space, it functions as a buffer member that reduces the impact when the maintenance member comes into contact with the head unit. In addition, since the buffer member is a single nozzle plate that extends over a plurality of droplet ejection heads, liquid is transferred from the nozzle opening side (droplet ejection surface side) to the back side (head holding member side) of each nozzle formation portion. Will not leak.

  If the nozzle plate is a single plate common to a plurality of droplet ejection heads, the impact when the cap member comes into contact with the nozzle plate is transmitted to the joint portion between the nozzle formation portion and the flow path structure. There is a possibility that the nozzle plate may be peeled off from the flow path structure. In the present invention, the rigidity reduction portion reduces the rigidity of the contact portion with the lip portion of the nozzle plate or the surrounding portion thereof, whereby the deformation of the contact portion is promoted to improve the shock absorbing effect, and the flow is reduced. It is possible to suppress the impact from propagating to the joint portion with the road structure. Thereby, peeling from the flow path structure of a nozzle plate is prevented.

According to a third aspect of the present invention, in the second invention, the nozzle plate is fixed to the head holding member at an edge of the nozzle plate, and the rigidity reduction portion is connected to the lip portion of the nozzle plate. It is provided only between the contact part of this and the junction part with the said flow-path structure located inside this contact part, It is characterized by the above-mentioned.

  If a reduced-rigidity portion is provided between the contact portion of the nozzle plate with the lip portion and the joint portion with the flow path structure inside the nozzle plate, deformation of the contact portion is promoted. The impact is absorbed and the impact is difficult to be transmitted from the contact portion to the joint portion with the flow path structure. On the other hand, since there is no rigidity reduction portion between the abutting portion of the nozzle plate and the lip portion and the edge portion fixed to the head holding member, the nozzle plate is more than the abutting portion. The rigidity of the outer part remains high. Therefore, the deformation of the nozzle plate when the cap member comes into contact with each other prevents the cap member from adhering to the nozzle plate from being lowered and the cap member from being deteriorated in airtightness as much as possible.

According to a fourth aspect of the present invention, there is provided a liquid droplet ejecting apparatus comprising: a head unit having a plurality of liquid droplet ejecting heads having nozzles that eject liquid droplets; and a head holding member that holds the plurality of liquid droplet ejecting heads; A maintenance member that is pressed against the unit from the nozzle opening side to maintain or restore the ejection performance of the plurality of droplet ejection heads, and is provided at a position closer to the nozzle opening than the head holding member. A cushioning member that contacts the maintenance member when pressed against the head unit and reduces an impact transmitted from the maintenance member to the head holding member, and the maintenance member is formed on an outer peripheral portion thereof. A cap member having a lip portion, wherein the lip portion of the cap member abuts against the buffer member, It is configured so that the nozzle of the droplet ejecting head is covered with the cap member, wherein the cushioning member is disposed in a state where there is a space between at least the lip portion portion and said head holding member contacting , the head holding member, and is characterized in that the communication unit to communicate with the outside the space formed between the cushioning member and the head holding member is provided.

  Since the space between the head holding member and the buffer member communicates with the outside, the buffer member is more easily deformed, and the impact when the maintenance member is pressed against the buffer member can be effectively absorbed.

  According to the present invention, when the maintenance member performs maintenance of the liquid droplet ejecting head, the maintenance member contacts the buffer member and does not directly contact the head holding member. In addition, there is a space between the portion of the buffer member that is in contact with the maintenance member and the head holding member. Therefore, when the maintenance member is pressed against the head unit, the shock-absorbing member is deformed, so that the impact (pressing force) at that time is alleviated, so that the deformation of the head holding member is suppressed.

It is a top view of the inkjet printer which concerns on this embodiment. It is a longitudinal cross-sectional view of a head unit. It is a figure which shows the structural example of the rigidity fall part of a nozzle plate. It is a longitudinal cross-sectional view of the head unit which concerns on a modified form.

  Next, an embodiment of the present invention will be described. The present embodiment is an example in which the present invention is applied to an ink jet printer.

  FIG. 1 is a top view of the ink jet printer according to the present embodiment. As shown in FIG. 1, an inkjet printer 1 (hereinafter simply referred to as a printer 1) includes a head unit 2 having an inkjet head 10 that ejects ink, and a transport mechanism 3 that transports a recording paper 100 to the head unit 2. And a maintenance unit 4 that performs maintenance and recovery (hereinafter also referred to as maintenance) of the droplet ejection performance of the inkjet head 10. 1 is the front-back direction, the left-right direction (main scanning direction: direction perpendicular to the transport direction) in FIG. 1 is the left-right direction, and the direction perpendicular to the paper surface of FIG. Is defined as the vertical direction (the front side of the page is the upper side), and the following description will be made using direction words such as front and rear, left and right, and up and down as appropriate.

  As shown in FIG. 1, the head unit 2 is arranged above the platen 5 installed horizontally (the front side in FIG. 1) when recording an image on a recording sheet. The head unit 2 includes four inkjet heads 10 (droplet ejection heads) each having nozzles 13 arranged in the left-right direction (main scanning direction), and a head holding member 11 that holds the four inkjet heads 10. .

Each ink-jet head 10 is supplied with ink from an ink cartridge (not shown) mounted on the casing 6 of the printer 1 via a tube 29 (see FIG. 2). Then, the ink jet head 10 ejects ink droplets toward the recording paper 100 on the platen 5 from the nozzle 13 that opens downward (the other side in FIG. 1). In this embodiment, as shown in FIG. 1, each of the inkjet heads 10 has two nozzle rows 14 arranged in a staggered manner, and each of the four inkjet heads 10 has an opening surface of the nozzle 13 ( Hereinafter, four droplet ejection surfaces 15 (see FIG. 2) are arranged in a zigzag manner in the same horizontal plane with the surface facing downward.
The head holding member 11 that holds the four inkjet heads 10 is a plate-like member, and is connected to the frame member 12 at both ends in the main scanning direction, and is connected to the casing 6 of the printer 1 via the frame member 12. It is fixed.

  The transport mechanism 3 includes a supply roller 16 and a discharge roller 17 that are disposed so as to sandwich the head unit 2 back and forth, and the recording unit 100 is moved along the platen 5 by the two rollers 16 and 17. Are conveyed in the sub-scanning direction.

  The printer 1 ejects ink droplets from the four inkjet heads 10 of the head unit 2 onto the recording paper 100 while transporting the recording paper 100 in the sub-scanning direction by the rollers 16 and 17 of the transport mechanism 3. Thus, a desired image is recorded on the recording paper 100.

  As shown in FIG. 1, the maintenance unit 4 is installed on the right side of the platen 5 when maintenance of the head unit 2 is not performed. On the other hand, when the maintenance of the head unit 2 becomes necessary, the maintenance unit 4 is configured to move to a position facing the head unit 2 by a position switching mechanism (not shown) having an appropriate configuration.

  The maintenance unit 4 includes a cap member 18 made of an elastic member such as rubber, a suction pump 19 connected to the cap member 18, a wiper 27 that wipes ink adhering to the droplet ejection surface 15 of the inkjet head 10, and the like. Have. The cap member 18 is driven in the vertical direction by a cap lifting mechanism (not shown) configured by a drive source such as a motor and a power transmission member such as a gear. When the cap member 18 is pressed against the head unit 2 while the head unit 2 is in the maintenance position, and the lip portion 18a on the outer periphery thereof is in close contact, the droplet ejection surfaces 15 of the four inkjet heads 10 are It is designed to cover at once. Thereby, when the head unit 2 is not used, the nozzle 13 is blocked from the atmosphere, and the ink in the nozzle 13 is prevented from drying.

  In addition, the suction pump 19 reduces the pressure in the cap member 18 in a state where the cap member 18 covers the droplet ejection surfaces 15 of the four inkjet heads 10, so that the suction pumps 19 are discharged from the nozzles 13 of the four inkjet heads 10. The ink is forcibly discharged (suction purge). Due to this suction purge, the nozzle 13 can be prevented from ejecting nozzles, or can cause ejection abnormalities such as ejection bending, foreign matter and bubbles mixed in the ink flow path, or thickened ink generated by drying in the nozzle 13, etc. 13 can be discharged.

  The wiper 27 is made of an elastic member such as rubber. The wiper 27 moves with respect to the head unit 2 in a state in which the tip portion thereof is in close contact with the droplet ejection surface 15 of the inkjet head 10, so that the ink attached to the droplet ejection surface 15 after a suction purge or the like. Wipe off.

  In the above description, the maintenance unit 4 is moved to a position facing the head unit 2 during maintenance by the maintenance unit 4, but conversely, the head unit 2 is moved relative to the maintenance unit 4. May be configured such that the two move and face each other.

  Next, a specific configuration of the head unit 2 will be described. FIG. 2 is a longitudinal sectional view of the head unit 2 of FIG. As described above, the head unit 2 includes the four inkjet heads 10 and the rectangular plate-like head holding member 11 that holds the four head units 2.

  The inkjet head 10 includes a flow path unit 20 (flow path structure) and a nozzle plate 21 joined to the flow path unit.

  As shown in FIG. 2, the flow path unit 20 has a substantially rectangular parallelepiped outer shape, and two ends for fixing the flow path unit 20 to the head holding member 11 at both ends in the left-right direction (main scanning direction). The fixing portion 22 is provided so as to protrude from the side surface of the flow path unit 20.

  An ink supply unit 23 connected to an ink cartridge (not shown) and a tube 29 is provided on the upper surface of the flow path unit 20. An ink flow path 24 (flow path portion) for supplying the ink supplied from the ink supply unit 23 to the plurality of nozzles 13 formed on the nozzle plate 21 described below is provided inside the flow path unit 20. ) Is formed. More specifically, as the ink flow path 24, a plurality of individual flow paths that respectively communicate with the plurality of nozzles 13, a common ink chamber that distributes ink to the plurality of individual flow paths, and the like are formed. On the lower surface of 20, channel ends of a plurality of individual channels are opened. Although not shown in the drawing, the flow path unit 20 is also provided with an actuator for applying an ejection pressure to the ink in the individual flow path corresponding to each of the plurality of nozzles 13.

  The nozzle plate 21 is a thin plate formed of a metal material or a synthetic resin material such as polyimide. The nozzle plate 21 has a nozzle forming portion 21a formed so that the plurality of nozzles 13 of the inkjet head 10 penetrate in the plate thickness direction. Then, the upper surface of the nozzle forming portion 21a is aligned with the flow channel end of the individual flow channel opened to the lower surface of the flow channel unit 20 and the nozzle 13 formed in the nozzle forming portion 21a of the nozzle plate 21 being aligned. By being joined to the lower surface of the flow path unit 20, the individual flow path on the flow path unit 20 side and the nozzle 13 on the nozzle plate 21 side communicate with each other. Further, the lower surface of the nozzle forming portion 21a becomes a surface where the plurality of nozzles 13 are opened to the outside, that is, the droplet ejecting surface 15.

  In the present embodiment, the nozzle plate 21 has a configuration common to the four inkjet heads 10 provided over the four inkjet heads 10. That is, the nozzle plate 21 has four nozzle forming portions 21a in which the nozzles 13 of the four inkjet heads 10 are formed, and the four flow path units 20 are joined to the four nozzle forming portions 21a, respectively. Thus, four inkjet heads 10 are configured.

  As shown in FIG. 2, the head holding member 11 is formed with four mounting holes 11 a corresponding to the four inkjet heads 10, respectively. Then, with the flow path units 20 of the four inkjet heads 10 inserted into the four mounting holes 11a, each flow path unit 20 holds the head with screws or the like at the two fixing portions 22 protruding from the side surfaces. It is fixed to the member 11.

  As shown in FIG. 2, the lower end portion of the flow path unit 20 protrudes further downward from the head holding member 11 through the mounting hole 11 a of the head holding member 11. As a result, the nozzle plates 21 respectively joined to the lower surfaces of the four flow path units 20 are in contact with the head holding member 11 on the lower side of the head holding member 11 (opening side of the nozzle 13: droplet ejection surface 15 side). It will be arranged with a space (gap) between them. The head holding member 11 is formed with one or a plurality of communication holes 11b for communicating the space between the nozzle plate 21 and the outside. Further, the edge of the nozzle plate 21 is joined to the edge of the head holding member 11 and fixed to the head holding member 11. Further, the edge portions of the head holding member 11 and the nozzle plate 21 joined to each other are fixed to the frame member 12, respectively.

  By the way, the nozzle plate 21 mentioned above is arrange | positioned so that the head holding member 11 may be covered from the lower side while it is respectively joined to the flow-path unit 20 of the four inkjet heads 10. FIG. Therefore, when the cap member 18 of the maintenance unit 4 described above is pressed against the head unit 2 during the maintenance of the ink jet head 10, as shown in FIG. The nozzle plate 21 abuts on a portion 21 b surrounding the four nozzle forming portions 21 a (droplet ejection surface 15) and does not directly contact the head holding member 11.

  Further, since there is a space between the head holding member 11 and the contact portion 21b with which the cap member 18 contacts the nozzle plate 21, the nozzle plate 21 is easily deformed at the contact portion 21b. In addition, when the lip portion 18a of the cap member 18 comes into contact, the nozzle plate 21 is deformed, so that an impact (pressing force) acting at the time of contact is alleviated. That is, the nozzle plate 21 also functions as a buffer member that reduces the impact when the cap member 18 abuts. Thereby, almost no impact acts on the head holding member 11, and deformation of the head holding member 11 is suppressed.

  Furthermore, since the communication hole 11b (communication part) which connects the space between the nozzle plate 21 to the exterior is formed in the head holding member 11, when the cap member 18 contacts, the nozzle plate 21 It becomes easier to deform and can absorb shock more effectively. The nozzle plate 21 may be provided with a communication hole that allows the space to communicate with the atmosphere. In this case, at least the lip portion 18a and the lip 18a are not damaged so as not to impair airtightness when the cap member 18 is attached. It is necessary to be provided in a portion outside the contact portion 21b.

  In the present embodiment, since the nozzle plate 21 is a single plate extending over the four inkjet heads 10, the ink discharged from the nozzle 13 and attached to the droplet ejection surface 15 (particularly, the nozzle during the suction purge) The ink discharged from the nozzle 13 and filled in the cap member 18 does not leak to the back side of the nozzle plate 21 (the head holding member 11 side). Furthermore, since the nozzle forming portions 21a of the four inkjet heads 10 are formed on one nozzle plate 21, the flow paths are connected when the four flow path units 20 are joined to the nozzle plate 21 in the manufacturing stage. Even if there is a slight deviation in the joining position of the path unit 20, there is an effect that the positional deviation of the nozzles 13 between the four inkjet heads 10 does not occur.

  However, as in the present embodiment, when the nozzle plate 21 common to the four inkjet heads 10 functions as a buffer member that reduces the impact when the cap member 18 abuts, when the cap member 18 abuts Is transmitted from the contact portion 21b to the joint portion between the nozzle forming portion 21a and the flow path unit 20, and the nozzle plate 21 may be peeled off from the flow path unit 20. Therefore, in order to prevent the impact propagation to the joint portion with the flow path unit 20 while promoting the deformation of the contact portion 21b and effectively absorbing the impact, the nozzle plate 21 is provided with the contact portion 21b or A rigidity reduction portion that reduces the rigidity of the surrounding portion may be provided.

  FIG. 3 shows some specific examples of the above-described reduced rigidity portion of the nozzle plate 21. For example, as shown in FIG. 3A, the rigidity-decreasing portion is a concave portion 25a formed on the upper surface (lower surface or both surfaces) of the contact portion 21b, and the thickness of the contact portion 21b itself is the same. The deformation of the abutting portion 21b may be promoted by being thinner than other portions. As described above, since the contact portion 21b is easily deformed, the impact when the cap member 18 is contacted is surely absorbed, and as a result, the impact is less likely to act on the joint portion with the flow path unit 20. The peeling of the nozzle plate 21 from the flow path unit 20 is prevented.

  In addition, as shown in FIG. 3B, a recess 25b as a rigidity reduction portion may be formed around the contact portion 21b. Thus, since the deformation restraining force from the periphery with respect to the contact part 21b weakens because the rigidity of the part around the contact part 21b decreases, the deformation of the contact part 21b is also promoted.

  Alternatively, as shown in FIG. 3C, a recess 25 c may be provided only between the abutting portion 21 b of the nozzle plate 21 and the joint portion of the flow path unit 20. In this case, when the recessed part 25c (rigidity reduction part) is provided between the contact part 21b with the lip | rip part 18a of the nozzle plate 21, and the junction part with the flow path unit 20 inside this. The deformation of the contact portion 21b is promoted and the impact is absorbed, and the impact is hardly transmitted from the contact portion 21b to the joint portion with the flow path unit 20. On the other hand, since no recess is provided between the contact portion 21b of the nozzle plate 21 with the lip portion 18a and the edge fixed to the head holding member 11, the contact of the nozzle plate 21 The rigidity of the part outside the part 21b remains high. Therefore, the deformation of the nozzle plate 21 when the cap member 18 is brought into contact with each other prevents the cap member 18 from being closely adhered to the nozzle plate 21 and the cap member 18 from being deteriorated in airtightness as much as possible.

  Alternatively, the concave portions 25c and 25d are formed on the inner side (joining side with the flow path unit 20) and the outer side (edge side) of the contact portion 21b of the nozzle plate 21, respectively, and the two concave portions 25c and 25d are formed. The shape and number may be different from each other. For example, as shown in FIG. 3D, the inner recess 25c may be formed deeper than the outer recess 25d. Alternatively, as shown in FIG. 3E, the inner recess 25c may be formed wider than the outer recess 25d. Although not shown, the inner recess 25c may be longer than the outer recess 25d. Alternatively, the number of the inner recesses 25c may be larger than that of the outer recesses 25d. In these configurations, the deformation of the contact portion 21b is promoted by the recesses 25c and 25d provided on both sides of the contact portion 21b, and the outer side (edge side) of the contact portion 21b is the inner portion. Therefore, the cap member 18 is prevented from being deteriorated in adhesion with the nozzle plate 21.

  In addition, a rigidity reduction part is not limited to the recessed part formed in the surface of the nozzle plate 21 like Fig.3 (a)-(e). For example, as shown in FIG. 3 (f), the nozzle plate 21 may have a structure in which two or more sheets 26 are laminated, and a cavity 25 e as a rigidity reduction portion may be formed between the sheets 26. Or a rigidity reduction part may be comprised by forming a part of nozzle plate 21 with a material with a low elasticity modulus compared with a part other than that.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] In the above-described embodiment, the nozzle plate 21 common to the four inkjet heads 10 is disposed on the opening side of the nozzle 13 with respect to the head holding member 11, and the nozzle plate 21 is pressed against the cap member 18. However, the present invention may have a configuration in which a dedicated buffer member is provided.

  In the head unit 2A of FIG. 4, unlike the one of FIG. 2 of the above embodiment, the flow path unit 20A of each inkjet head 10 also has a plurality of nozzles 13, and the lower surface of the flow path unit 20 has a plurality of nozzles 13. It is an open droplet ejection surface 15. On the other hand, below the head holding member 11, a plate-like buffer member 30 is disposed in parallel with a space between the head holding member 11 and the edge of the buffer member 30 is fixed to the head holding member 11. Has been. The buffer member 30 is formed with four holes 30a, and the lower ends of the flow path units 20A of the four inkjet heads 10A are inserted into the four holes 30a, respectively. Further, the lower surface (droplet ejection surface 15) of the four flow path units 20A and the lower surface of the buffer member 30 are substantially flush, and the four holes 30a on the lower surface of the buffer member 30 are used for maintenance. The lip portion 18a of the cap member 18 comes into contact with the outer portion. The hole 30 a of the buffer member 30 is slightly larger than the flow path unit 20, but a sealing material 31 is filled between the hole 30 a and the flow path unit 20. Thereby, the airtightness in the cap member 18 at the time of suction purge is maintained.

  Also in this configuration, the cap member 18 abuts against the buffer member 30 positioned with a space below the head holding member 11 and does not directly contact the head holding member 11 as in the above embodiment. The shock when the member 18 is pressed is alleviated by the buffer member 30, and the deformation of the head holding member 11 is suppressed. However, since the inkjet head 10A (flow path unit 20A) is inserted into the hole 30a formed in the buffer member 30, the ink on the droplet ejection surface 15 side (particularly, discharged from the nozzle 13 by suction purge). Since the ink filled in the cap member 18 may leak to the back side (the head holding member 11 side), it is necessary to securely seal between the hole 30a and the flow path unit 20 with a sealing material. is there. Further, when the head unit 2A is assembled, if the positioning accuracy of the flow path unit 20A with respect to the hole 30a of the buffer member 30 is poor, the position of the nozzle 13 is shifted between the four flow path units 20A. It is necessary to accurately position the flow path unit 20A when inserting the flow path unit 20A.

2] The communication portion that communicates the space between the head holding member and the buffer member with the outside is not limited to the communication hole 11b (see FIG. 2) as in the above embodiment. For example, in FIG. 4 mentioned above, the slight gap 32 existing between the head holding member 11 and the flow path unit 20A allows the space between the head holding member 11 and the buffer member 30 to communicate with the outside. It may function as.

3] In the above-described embodiment, a configuration in which the droplet ejection surfaces 15 of the plurality of inkjet heads 10 are covered with the common cap member 18 is described. However, the droplet ejection surfaces 15 of the inkjet heads 10 are individual cap members. The structure covered with may be sufficient. In the above-described configuration, a support portion that supports the buffer member 30 (nozzle plate 21) disposed across the plurality of inkjet heads 10 from the side opposite to the droplet ejection surface 15 is disposed between the plurality of inkjet heads 10. It is preferable to be provided.

4] The cap member 18 of the above-described embodiment covers the droplet ejection surface 15 to prevent the nozzle 13 from drying in order to maintain the droplet ejection performance of the inkjet head 10 during standby when the head unit 2 is not used. It fulfills both the function as a protective cap and the function as a so-called suction cap for performing the suction purge to recover the lowered droplet jetting performance, but only fulfills one of the functions It may be.

5] As the maintenance member for maintaining or recovering the droplet ejection performance of the inkjet head 10, the cap member 18 has been described as an example in the above embodiment, but the maintenance member of the present invention is not limited to the cap member 18, The present invention can be applied to a configuration provided with other maintenance members as long as it is pressed against the head unit 2 in order to maintain or recover the ejection performance of the nozzle 13.

  For example, when the ink attached to the droplet ejection surface 15 of the inkjet head 10 is wiped with the wiper 27 (see FIG. 1), the lower surface of the head unit 2 including the droplet ejection surfaces 15 of the plurality of inkjet heads 10 is In the configuration in which the wiper 27 is in direct contact with the head holding member 11 when wiping is performed at once, the head holding member 11 may be deformed by an impact (pressing force) received from the wiper 27. Even in such a case, by providing a buffer member on the opening side (droplet ejection surface 15 side) of the nozzle 13 relative to the head holding member 11, the wiper 27 does not directly contact the head holding member 11, and the head holding member 11. Can be suppressed.

6] The head unit 2 of the above embodiment is a fixed head unit that is fixed in position during image recording and ejects ink droplets onto the conveyed recording paper 100. However, the width of the recording paper 100 The present invention can also be applied to a so-called serial type head unit that ejects ink droplets onto the recording paper 100 while moving in the direction (direction orthogonal to the paper transport direction). is there.

  The above-described embodiment and its modifications are examples in which the present invention is applied to an inkjet printer that is a kind of droplet ejecting apparatus and ejects ink to record an image or the like on recording paper. The target is not limited to this. That is, the present invention can be applied regardless of the type, application, and technical field of the liquid to be ejected.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2, 2A Head unit 10, 10A Inkjet head 11 Head holding member 11b Communication hole 13 Nozzle 15 Droplet ejection surface 18 Cap member 18a Lip part 20, 20A Flow path unit 21 Nozzle plate 21a Nozzle formation part 21b Contact part 24 Ink channels 25a to 25c Concave portion 25d Cavity 27 Wiper 30 Buffer member

Claims (4)

A head unit having a plurality of liquid droplet ejecting head having nozzles for ejecting liquid droplets, and a head holding member for a hold said plurality of droplet ejection heads,
A maintenance member that is pressed against the head unit from the nozzle opening side to maintain or recover the ejection performance of the plurality of droplet ejection heads;
A buffer member that is provided at a position closer to the nozzle opening than the head holding member, contacts the maintenance member when pressed against the head unit, and cushions an impact transmitted from the maintenance member to the head holding member ; With
The maintenance member is a cap member having a lip portion formed on an outer peripheral portion thereof, and the nozzles of the plurality of liquid droplet ejecting heads are formed on the cap member by the lip portion of the cap member coming into contact with the buffer member. Configured to be covered by
The cushioning member is arranged closer in a state between air is present between the portion and the front SL head holding member at least the lip portion is in contact, the rigidity of the contact portion or the peripheral portion thereof with the lip portion A liquid droplet ejecting apparatus having a rigidity lowering portion that locally lowers water. A head unit having a plurality of liquid droplet ejecting head having nozzles for ejecting liquid droplets, and a head holding member for a hold said plurality of droplet ejection heads,
A maintenance member that is pressed against the head unit from the nozzle opening side to maintain or recover the ejection performance of the plurality of droplet ejection heads;
A buffer member that is provided at a position closer to the nozzle opening than the head holding member, contacts the maintenance member when pressed against the head unit, and cushions an impact transmitted from the maintenance member to the head holding member ; With
The plurality of liquid droplet ejecting heads have a plurality of flow channel structures respectively formed with flow channel portions communicating with the nozzles and held by the head holding member,
The buffer member is a nozzle plate that is common to the plurality of droplet ejecting heads, and includes a plurality of nozzle forming portions in which the nozzles of the plurality of droplet ejecting heads are respectively formed.
One droplet ejecting head is configured by joining one flow path structure to one nozzle forming portion of the nozzle plate,
The maintenance member is a cap member having a lip portion formed on an outer peripheral portion thereof, and the lip portion of the cap member comes into contact with a portion outside the plurality of nozzle forming portions of the nozzle plate. The nozzles of a plurality of droplet ejection heads are configured to be covered with the cap member,
The nozzle plate is arranged closer in a state between air is present between the portion and the front SL head holding member at least the lip portion is in contact, the rigidity of the contact portion or the peripheral portion thereof with the lip portion It has a rigidity reduction part which suppresses that the impact when the said cap member contact | abuts is transmitted locally to the junction part of the said flow-path structure and the said nozzle formation part. Droplet ejector. The nozzle plate is fixed to the head holding member at an edge thereof,
The rigidity reduction portion is provided only between a contact portion of the nozzle plate with the lip portion and a joint portion with the flow path structure located inside the contact portion. The droplet ejecting apparatus according to claim 2 . A head unit having a plurality of liquid droplet ejecting head having nozzles for ejecting liquid droplets, and a head holding member for a hold said plurality of droplet ejection heads,
A maintenance member that is pressed against the head unit from the nozzle opening side to maintain or recover the ejection performance of the plurality of droplet ejection heads;
A buffer member that is provided at a position closer to the nozzle opening than the head holding member, contacts the maintenance member when pressed against the head unit, and cushions an impact transmitted from the maintenance member to the head holding member ; With
The maintenance member is a cap member having a lip portion formed on an outer peripheral portion thereof, and the nozzles of the plurality of liquid droplet ejecting heads are formed on the cap member by the lip portion of the cap member coming into contact with the buffer member. Configured to be covered by
The buffer member is disposed in a state where between air is present between the portion and the front SL head holding member at least the lip portion is in contact,
The liquid droplet ejecting apparatus according to claim 1, wherein the head holding member is provided with a communication portion that communicates the space formed between the head holding member and the buffer member with the outside .

Images