JP2013139157A - Droplet discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control bending of a head from both sides of a heat factor and a load factor.SOLUTION: The head 10 is supported by a holder 20 made of a resin along a longitudinal direction. A reinforcing member 30 is arranged above the head 10 pinching the holder 20. The reinforcing member 30 is prepared by forming a metal plate in U shape in cross sectional view to function as a heat sink of a driver IC 45, and to reinforce flexural rigidity in a lengthwise direction of the head of the head 10 and the holder 20, wherein the flexural rigidity in the longitudinal direction thereof is larger than those of the head 10 and the holder 20. The holder 20 and the reinforcing member 30 make point contacts by a plurality of projections 21p and 23p formed in the holder 20.

Description

  The present invention relates to a droplet discharge device including a droplet discharge head and a holder that supports the droplet discharge head.

  An ink jet head unit, which is an example of a droplet discharge device, is applied to a recording apparatus such as an ink jet printer. In the head unit, in particular, when a line-type long head is included, the head is easily bent in the longitudinal direction, and various techniques for suppressing the bending in the longitudinal direction of the head (hereinafter simply referred to as “deflection”). Has been proposed. The deflection of the head can be caused by various factors (two factors of a thermal factor and a load factor if roughly classified) such as a change in environmental temperature, the head's own weight, and a load load when the head is attached to the printer body. If the head bends, the position of each nozzle on the ejection surface of the head may deviate from the desired position, the ejection direction of the ink droplets from the nozzle may change, or the spacing between the ejection surface and the recording medium may not be constant. As a result, the recording quality deteriorates.

  For example, Patent Document 1 proposes that the upper and lower surfaces of both ends of the head in the longitudinal direction are fixed to a support frame fixed to the printer main body in order to suppress the deflection of the head due to a change in environmental temperature as a thermal factor. ing.

Japanese Patent Laid-Open No. 2007-112067

  However, in Patent Document 1, the load factor is not taken into consideration, and the deflection of the head due to the load factor (due to the head's own weight, the load load on the head, or the like) cannot be suppressed. Here, in order to suppress the deflection of the head due to a load factor, it may be possible to reinforce the bending rigidity of the head by attaching a reinforcing member made of metal or the like to the head. May be transmitted to the head, and the head may be bent by heat. Therefore, it is desired to suppress the deflection of the head from both the thermal and load factors.

  An object of the present invention is to provide a droplet discharge device capable of suppressing head deflection from both sides of thermal factors and load factors.

To achieve the above object, according to a first aspect of the present invention, a droplet discharge head having a plurality of nozzles for discharging droplets and a plurality of actuators respectively corresponding to the nozzles, and a longitudinal direction of the droplet discharge head A bending rigidity in the longitudinal direction connected to the holder via a holder that supports the droplet discharge head along the plurality of point contact portions spaced apart along the longitudinal direction. A large reinforcing member, and the droplet discharge head is fixed to the holder by a fixing member while being separated from the holder via a gap on the side opposite to the reinforcing member with respect to the holder. A featured droplet ejection device is provided.
In the first aspect, the gap may be sandwiched between the plurality of fixing members in a direction parallel to a surface of the holder that faces the droplet discharge head while being spaced apart.
According to a second aspect of the present invention, a line-type inkjet head having a plurality of nozzles for ejecting ink droplets and a plurality of piezoelectric actuators respectively corresponding to the nozzles, and a driver IC for outputting a drive signal to the actuators A holder for supporting the inkjet head along the longitudinal direction of the inkjet head, the holder having a flat plate-like support plate extending in the longitudinal direction, and a heat sink for the driver IC, wherein the longitudinal A heat sink having a larger bending stiffness in the direction than the holder, and the inkjet head is fixed to the support plate by a fixing member while being separated from the support plate via a gap on one surface side of the support plate A plurality of gaps in a direction parallel to the one surface. The heat sink is connected to the support plate via a plurality of point contact portions spaced apart from each other along the longitudinal direction on the other surface side of the support plate. The droplet contact device is characterized in that the point contact portion is formed by a plurality of protrusions protruding from the other surface in a direction approaching the heat sink.
In the second aspect, the heat sink includes a bottom portion facing the support plate, and a protruding portion protruding in a direction intersecting the bottom portion from an end portion of the bottom portion, and the driver IC includes the protruding portion. The heat sink may have an opening extending in the longitudinal direction at a position closer to the support plate than a position at which the driver IC is attached.

  According to the first and second aspects, the bending rigidity in the longitudinal direction of the head and the holder is reinforced by the reinforcing member, so that bending in the longitudinal direction of the head due to a load factor can be suppressed. In addition, since the reinforcing member is connected to the holder via the point contact portion, heat transfer from the reinforcing member to the holder and further to the head is suppressed, and bending of the head in the longitudinal direction due to thermal factors can be suppressed. it can. Therefore, according to the first and second aspects, the deflection of the head can be suppressed from both the load factor and the thermal factor.

  In the first aspect, the reinforcing member may be attached with a drive circuit that outputs a drive signal to the actuator, and may function as a heat sink for the drive circuit. In this case, by using a heat sink generally provided in the droplet discharge device as a reinforcing member, the above effect can be obtained with a simple configuration without adding the number of components.

  In the first aspect, the holder may be sandwiched between the droplet discharge head and the reinforcing member. In this case, the reinforcement of the holder is improved, and thus the reinforcement of the head is improved.

  In the first aspect, the point contact portion may be formed by a plurality of protrusions protruding in a direction approaching the reinforcing member from a surface facing the reinforcing member while being separated from the reinforcing member in the holder. In this case, the point contact portion can be formed with a simple configuration.

In the first aspect, the protrusion may form a plurality of rows along the longitudinal direction on the surface of the holder. In this case, the holder and the reinforcing member can be connected uniformly over the longitudinal direction.
In the first aspect, the holder protrudes in a direction approaching the reinforcing member from the surface of the holder and is inserted into the reinforcing member, and a direction approaching the reinforcing member in the shaft main body And has a crimping portion that supports a surface of the reinforcing member opposite to the surface facing the holder, and the protrusion supports the surface of the reinforcing member facing the holder. The reinforcing member and the holder may be connected to each other by the point contact portion formed by the protrusion and the caulking portion.
In the first aspect, the protrusions may be arranged in a symmetric positional relationship around the shaft main body on the surface of the holder.
In the first aspect, the plurality of caulking portions are arranged along the longitudinal direction to form one row, and the protrusions are provided one on each side of the shaft body with respect to a direction orthogonal to the longitudinal direction. It may be arranged.

  In the first aspect, in addition to the point contact portion, the reinforcing member and the holder are connected with a member having a lower thermal conductivity than the reinforcing member and the holder sandwiched between the reinforcing member and the holder. The parts may be connected to each other. In this case, the reinforcement member and the holder are connected not only by the point contact portion but also by the connection portion, so that the connection between these members is strengthened. In addition, since a member having low thermal conductivity is sandwiched between the members in the connection portion, it is possible to strengthen the connection between the members while suppressing heat transfer from the reinforcing member to the holder and further to the head. .

  In the first aspect, the reinforcing member may include a bottom portion that faces the holder, and a protruding portion that protrudes from an end portion of the bottom portion in a direction intersecting the bottom portion. In this case, the reinforcing effect by the reinforcing member can be improved.

  In the first aspect, a drive circuit that outputs a drive signal to the actuator may be attached to the outer surface of the protrusion. In this case, compared with the case where the drive circuit is attached to the bottom of the reinforcing member, heat generated in the drive circuit is less likely to be transmitted from the reinforcing member to the holder and the head. Moreover, compared with the case where a drive circuit is attached to the inner surface of a protrusion part, the heat which generate | occur | produced in the drive circuit is easily dissipated outside, and heat transfer to a holder and a head can be suppressed.

In the first aspect, a drive circuit that outputs a drive signal to the actuator may be attached to an end portion of the projecting portion that is separated from the holder. In this case, since the distance between the drive circuit and the holder is relatively long, heat generated in the drive circuit is hardly transmitted from the reinforcing member to the holder and the head.
In the first aspect, the reinforcing member may include two protruding portions, and a cross section intersecting the longitudinal direction may be U-shaped.

  In the first aspect, the reinforcing member has an opening extending in the longitudinal direction at a position closer to the holder than a position at which a driving circuit that outputs a driving signal to the actuator is attached. Good. In this case, the thermal resistance of the reinforcing member is improved by the opening, and the heat generated in the drive circuit is not easily transmitted from the reinforcing member to the holder and the head.

  According to the present invention, since the bending rigidity in the longitudinal direction of the head and the holder is reinforced by the reinforcing member, it is possible to suppress bending in the longitudinal direction of the head due to a load factor. In addition, since the reinforcing member is connected to the holder via the point contact portion, heat transfer from the reinforcing member to the holder and further to the head is suppressed, and bending of the head in the longitudinal direction due to thermal factors can be suppressed. it can. Therefore, according to the present invention, it is possible to suppress the deflection of the head from both the load factor and the thermal factor.

1 is a schematic side view showing an internal structure of an ink jet printer including an ink jet head unit as a first embodiment of a droplet discharge device according to the present invention. It is a figure which shows the inkjet head unit of FIG. 1, (a) is a perspective view, (b) is a side view. FIG. 3 is a perspective view showing a state where a cover is removed from the head unit of FIG. 2. (A) is a perspective view which shows the state which removed further the base from the head unit of FIG. (B) is a top view of (a). FIG. 5 is a perspective view showing a state where a flexible printed board is further removed from the head unit of FIG. 4. It is sectional drawing along the VV line of FIG.2 (b). FIG. 5 is a partial cross-sectional perspective view taken along line VV in FIG. It is a top view which shows the flow-path unit of the inkjet head contained in the inkjet head unit of FIG. It is an enlarged view which shows the area | region VIII enclosed with the dashed-dotted line of FIG. FIG. 10 is a partial cross-sectional view taken along line XX in FIG. 9. It is sectional drawing corresponding to FIG. 6 which shows the inkjet head unit as 2nd Embodiment of the droplet discharge apparatus which concerns on this invention.

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

  First, an overall configuration of an ink jet printer to which an ink jet head unit 1 as a first embodiment of a droplet discharge device according to the present invention is applied will be described with reference to FIG. As shown in FIG. 1, the head unit 1 is a long line type along one direction (a direction orthogonal to the paper surface of FIG. 1), and its longitudinal direction (the longitudinal direction of a discharge surface 10x of the head 10 described later). (Hereinafter referred to as “head longitudinal direction”) as the main scanning direction, and is applied to the ink jet printer 500.

  The printer 500 includes a rectangular parallelepiped housing 501a. A paper discharge unit 531 is provided on the top plate of the housing 501a. The internal space of the housing 501a is divided into spaces A, B, and C in order from the top. The four head units 1 according to the first embodiment of the present invention are arranged in parallel in the space A and eject magenta, cyan, yellow, and black inks, respectively. In the space A, a transport unit 521 that transports the paper P while sequentially facing the ejection surface 10x of each head unit 1 and a controller 501 that controls the operation of each part of the printer 500 are arranged. Each of the spaces B and C is a space in which a paper feed unit 501b and an ink unit 501c that can be attached to and detached from the housing 501a along the main scanning direction are arranged. Inside the printer 500, a paper transport path for transporting the paper P is formed along the thick arrow shown in FIG. 1 from the paper feed unit 501b toward the paper discharge unit 531.

  Here, the sub-scanning direction is a direction parallel to the conveyance direction of the paper P by the conveyance unit 521, and the main scanning direction is a direction orthogonal to the sub-scanning direction and along the horizontal plane.

  The paper feed unit 501 b includes a paper feed tray 523 that can store a plurality of sheets of paper P, and a paper feed roller 525 attached to the paper feed tray 523. The paper feed roller 525 is rotated by driving a paper feed motor (not shown) under the control of the controller 501, and feeds the paper P at the uppermost position of the paper feed tray 523. The paper P sent out by the paper supply roller 525 is guided by the guides 527a and 527b and sent to the transport unit 521 while being sandwiched by the feed roller pair 526.

  The transport unit 521 includes two belt rollers 506 and 507 and an endless transport belt 508 wound so as to be bridged between the two rollers 506 and 507. The belt roller 507 is a driving roller, and rotates under the control of the controller 501, driven by a conveyance motor (not shown) connected to the shaft, and rotates clockwise in FIG. The belt roller 506 is a driven roller, and rotates in the clockwise direction in FIG. 1 as the conveyor belt 508 travels as the belt roller 507 rotates.

  A substantially rectangular parallelepiped platen 519 is disposed in the loop of the conveyor belt 508 so as to face the four head units 1. The upper loop of the conveyor belt 508 is arranged so that the outer peripheral surface 508a of the conveyor belt 508 extends in parallel with the discharge surface 10x while being spaced apart from the discharge surfaces 10x of the four head units 1 by a platen 519 from the inner peripheral surface side. Is supported by

  A weak adhesive silicon layer is formed on the outer peripheral surface 508 a of the conveyor belt 508. The paper P sent from the paper supply unit 501b to the transport unit 521 is pressed against the outer peripheral surface 508a of the transport belt 508 by the pressing roller 504, and then held on the surface 508a by an adhesive force, and is indicated by a thick arrow. Along the sub-scanning direction.

  When the paper P passes immediately below the four head units 1, ink droplets of each color are sequentially ejected from the ejection surface 10 x of each head unit 1 toward the upper surface of the paper P under the control of the controller 501. Thus, a desired color image is formed on the paper P. The paper P is peeled off from the outer peripheral surface 508a of the transport belt 508 by the peeling plate 505, guided by the guides 529a and 529b, and transported upward while being sandwiched between the two pairs of feed rollers 528, and formed on the top of the housing 501a. The paper is discharged from the opened opening 530 to the paper discharge unit 531. One roller of each pair of feed rollers 528 is rotated by driving a feed motor (not shown) under the control of the controller 501.

  The four head units 1 are arranged in parallel along the sub-scanning direction at a predetermined interval, and are supported by the housing 501a via the head frame 503. That is, the printer 500 is a line type color ink jet printer.

  The ink unit 501c includes a cartridge tray 535 and four ink cartridges 540 corresponding to the four head units 1, respectively. The ink unit 501c is attachable to and detachable from the space C of the housing 501a in a state where four cartridges 540 are arranged side by side on the tray 535 in the sub-scanning direction.

  Next, the configuration of the head unit 1 will be described.

  The head unit 1 includes an inkjet head 10 having a discharge surface 10x on the lower surface, a resin holder 20 that supports the head 10, a metal reinforcing member 30 (see FIG. 5) connected to the holder 20, and a reinforcing member 30 interposed therebetween. The base 50 (refer FIG. 3) attached above the holder 20 and the cover 2 etc. are included. An ink flow path is formed inside the head 10, and a number of nozzles 18 (see FIG. 10) communicating with the ink flow path are opened on the ejection surface 10x. The holder 20 supports the head 10 along the longitudinal direction of the head. The reinforcing member 30 has a U-shaped cross section and is connected to the holder 20 at a plurality of locations along the longitudinal direction of the head. The cover 2 is fixed to the upper end of the side plate 22 of the holder 20, and the reinforcing member 30 and the base portion 50 are accommodated in a space formed by the holder 20 and the cover 2. Note that the lengths of the head 10, the holder 20, the reinforcing member 30, the base 50, and the cover 2 in the head longitudinal direction are substantially the same.

  As shown in FIG. 2, the cover 2 is a box-shaped member that is long along the longitudinal direction of the head and is opened at the bottom. The cover 2 has substantially the same length as the holder 20 in the head width direction. As shown in FIG. 2A, the upper wall of the cover 2 is formed with through holes 2x at both ends in the head longitudinal direction. A joint 51 of the base 50 (see FIG. 3) is inserted into each through hole 2x. Further, on the upper wall of the cover 2, three elongated vent holes 2 y that connect the space in the cover 2 and the external space are formed.

  As shown in FIG. 3, the base 50 is a resin-made integrally formed member having a substantially rectangular parallelepiped shape that is long in the longitudinal direction of the head. The base 50 is fixed to the holder 20 at both ends in the head longitudinal direction. The base 50 has a main body extending in the longitudinal direction of the head and two cylindrical joints 51. A control board 52 (see FIGS. 6 and 7) and the like are assembled to the main body. The control board 52 is provided with circuit components such as a connector 52a and a capacitor. The control board 52 is electrically connected to a controller 501 (see FIG. 1) of the printer 500. The joint 51 extends along the vertical direction at both ends of the main body in the longitudinal direction of the head, and the lower end is fixed to the upper surface of the head 10 to communicate with the ink flow path of the head 10. Tubes for supplying and discharging ink are attached to the upper ends of the joints 51, respectively. Ink in the corresponding cartridge 540 (see FIG. 1) flows into the ink flow path of the head 10 through the supply tube and the one joint 51. Further, when purging or the like for eliminating clogging of the filter provided in the ink flow path of the head 10, the ink in the corresponding cartridge 540 (see FIG. 1) passes through the one joint 51 to the head. 10 flows into the ink flow path, passes over the filter, and is discharged to the waste ink tank through the other joint 51.

  As shown in FIGS. 6 and 7, the head 10 includes a reservoir unit 11 and a flow path unit 12 fixed to the lower side of the reservoir unit 11.

  The reservoir unit 11 is a laminated body formed by laminating and bonding four rectangular metal plates 11a, 11b, 11c, and 11d having substantially the same size. The third plate 11c from the top is formed with a through hole constituting the reservoir 11x. The reservoir 11x stores ink supplied through one joint 51 (see FIG. 2A). Inside the reservoir unit 11, an ink flow path including the reservoir 11x is formed. One end of the ink flow path communicates with one joint 51, and the other end of the ink flow path corresponds to the opening 11y on the lower surface. Each plate 11a, 11b, 11c, 11d is formed with a through-hole or a recess that constitutes the ink flow path.

  The flow path unit 12 is formed by stacking and bonding nine rectangular metal plates 12a, 12b, 12c, 12d, 12e, 12f, 12g, 12h, and 12i (see FIG. 10) of substantially the same size. Laminated body. As shown in FIGS. 6, 7, and 8, an opening 12 y corresponding to the opening 11 y of the reservoir unit 11 is formed on the upper surface of the flow path unit 12. Inside the flow path unit 12, an ink flow path is formed which is connected to the nozzle 18 on the lower surface from the opening 12y on the upper surface. Each of the plates 12a to 12i is formed with a through-hole or a recess that constitutes the ink flow path. As shown in FIGS. 8, 9, and 10, the ink channel includes a manifold channel 13 having an opening 12y at one end, a sub-manifold channel 13a branched from the manifold channel 13, and a sub-manifold channel. An individual ink flow path 14 extending from the outlet 13a to the nozzle 18 through the pressure chamber 16 is included. As shown in FIG. 10, the individual ink flow path 14 is formed for each nozzle 18 and includes an aperture 15 that functions as a diaphragm for adjusting the flow path resistance.

  In FIG. 9, the pressure chamber 16 and the aperture 15 that are to be indicated by dotted lines below the actuator unit 17 are indicated by solid lines.

  On the upper surface of the flow path unit 12, as shown in FIG. 8, eight trapezoidal actuator units 17 are arranged in a zigzag pattern in two rows. As shown in FIG. 9, in the trapezoidal region of the flow path unit 12 where the actuator units 17 face each other, a large number of substantially rhombic pressure chambers 16 are opened on the upper surface, and pressure chambers are formed on the lower surface (discharge surface 10x). As many as 16 nozzles 18 are open. The pressure chambers 16 and the nozzles 18 are arranged in a matrix in a trapezoidal region where the actuator units 17 are opposed to each other, and constitute a pressure chamber group and a nozzle group. Both the pressure chamber group and the nozzle group occupy an area similar to the actuator unit 17. As shown in FIG. 10, each pressure chamber 16 constituting the pressure chamber group is covered with a corresponding actuator unit 17. Although not shown, each actuator unit 17 has a plurality of trapezoidal piezoelectric sheets, individual electrodes facing each pressure chamber 16, and a common electrode common to all pressure chambers 16, that is, each corresponds to a nozzle 18. Including a large number of piezoelectric actuators.

  The reservoir unit 11 is adhered to a portion of the upper surface of the flow path unit 12 where the actuator unit 17 is not disposed (a region surrounded by a two-dot chain line including the opening 12y illustrated in FIG. 8). That is, the lower surface of the reservoir unit 11 has irregularities, and the tip surface of the convex portion is bonded to the upper surface of the flow path unit 12. An opening 11y communicating with the reservoir 11x is formed at the tip surface of the convex portion. On the other hand, the recess has a slight gap between the upper surface of the flow path unit 12, the surface of the actuator unit 17 bonded to the upper surface, and the surface of the flexible printed circuit board (FPC) 40 bonded to the surface of each actuator unit 17. Are facing each other.

  Each of the eight FPCs 40 is provided with a wiring corresponding to each electrode of the actuator unit 17, and a driver IC 45 is mounted in the middle thereof. Each FPC 40 is drawn from the lower bottom side of the trapezoidal actuator unit 17 shown in FIG. 8 to the side of the head 10 through the gap between the upper surface of the flow path unit 12 and the lower surface (recessed portion) of the reservoir unit 11. As shown in FIG. 4A, FIG. 6 and FIG. The FPC 40 further extends to the vicinity of the control board 52 through the gaps between the side walls of the reinforcing member 30 and the base 50 and the inner wall of the cover 2. The end of the FPC 40 is fixed to the connector 52 a of the control board 52. At this time, as shown in FIGS. 6 and 7, the driver IC 45 is disposed so as to face the side wall (projecting portion 32) of the reinforcing member 30, and is attached by the sponge-like elastic member 42 installed on the inner wall of the cover 2. By being urged, the projection 32 abuts. The FPC 40 transmits a signal output from the control board 52 to the driver IC 45 via the connector 52a, and transmits a drive signal generated in the driver IC 45 to the actuator unit 17.

  As shown in FIGS. 2, 6, and 7, the holder 20 includes a support plate 21 that extends in the longitudinal direction of the head and a pair of side plates 22. The support plate 21 is a flat plate member arranged in parallel with the discharge surface 10x. The side plate 22 is a flat plate member disposed so as to be orthogonal to the discharge surface 10x at both ends in the width direction of the support plate 21 (the same direction as the width direction of the head 10; hereinafter referred to as “head width direction”). Yes, and protrudes vertically with respect to the support plate 21. In the holder 20, the support plate 21 and the side plate 22 are integrally formed by injection molding or the like. A part of the reservoir unit 11 and the flow path unit 12 is accommodated in a space formed by the support plate 21 and a portion of the side plate 22 that protrudes downward from the support plate 21.

  As shown in FIGS. 6 and 7, the lower surface of the support plate 21 faces the upper surface of the reservoir unit 11 while being spaced apart, and is fixed to the upper surface of the reservoir unit 11 by a fixing member 29. The upper surface of the support plate 21 faces the bottom portion 31 of the reinforcing member 30 while being spaced apart. The support plate 21 has a shaft 23 and a protrusion 21p that protrude from the top surface in a direction approaching the bottom 31 (ie, upward), respectively.

  The shaft 23 is disposed at the center in the width direction of the support plate 21, and includes a shaft main body 23 a that is inserted into the through hole 31 x of the bottom 31 of the reinforcing member 30, and a crimped portion that is provided at the upper end of the shaft main body 23 a. 23b. The shaft body 23a has a diameter that is slightly smaller than the through hole 31x. The outer peripheral surface of the shaft main body 23a faces the wall that defines the through hole 31x in the bottom portion 31 while being spaced apart. On the outer peripheral surface of the shaft main body 23a, a plurality of protrusions 23p protruding from the outer peripheral surface in the direction approaching the wall, that is, outward are formed while being separated along the outer peripheral direction. The protrusion 23p is hemispherical, and is in point contact with the wall defining the through hole 31x in the bottom 31 at the tip. The caulking portion 23b is formed in a substantially hemispherical shape having a diameter larger than that of the through hole 31x, for example, by heating and melting the upper end of the shaft 23 to a temperature equal to or higher than the curing temperature of the thermosetting resin that is a constituent material of the holder 20. Yes, supporting the upper surface of the bottom 31. As shown in FIG. 4B, five shafts 23 are provided in a line along the longitudinal direction of the head.

  As shown in FIGS. 6 and 7, one protrusion 21 p is disposed on each side of the head 23 in the head width direction, that is, two protrusions 21 p are provided on one shaft 23. On the upper surface of the support plate 21, the two protrusions 21 p corresponding to one shaft 23 are symmetrical in the head width direction about the shaft 23, and the positional relationship is common to the protrusions 21 p corresponding to all the axes 23. ing. Therefore, the protrusions 21p form two rows on the upper surface of the support plate 21 along the longitudinal direction of the head with the row of the five shafts 23 sandwiched therebetween. The number of protrusions 21p included in each row is five, and a total of ten protrusions 21p are provided. Each projection 21p has a shape that tapers upward, and is in point contact with the lower surface of the bottom 31 at the tip.

  As shown in FIG. 6, each of the pair of side plates 22 has a notch 22a on the inner surface of the lower end, and is disposed so as to face the side portion of the reservoir unit 11 while being separated from each other in the head width direction. The lower surface of the notch 22a faces the upper surface end of the flow path unit 12 while being spaced apart, and the side surface of the notch 22a faces the upper end side face of the flow path unit 12 while being spaced apart. Although illustration is omitted, a potting agent (for example, silicone) is filled between the flow path unit 12 and the notch 22a, thereby preventing the ink mist from entering the head 1. The upper end of the side plate 22 is fixed to the lower end of the cover 2.

  One end 20c in the head longitudinal direction of the holder 20 (see FIG. 2B) is fixed to and supported by the head frame 503 (see FIG. 1) installed at a predetermined position of the printer 500. When the head unit 1 is attached to the frame 503, in order to position the head 10 (nozzles 18) with respect to the frame 503, a load is applied to the holder 20 and the head 10 in the direction of the arrow shown in FIG. .

  The reinforcing member 30 is formed by molding a plate made of a metal having high thermal conductivity such as copper or aluminum, and as shown in FIGS. 6 and 7, a bottom 31 extending in the longitudinal direction of the head, and two A protrusion 32 is included. The bottom portion 31 is disposed so as to face the support plate 21 of the holder 20 in parallel with the ejection surface 10x. The two protruding portions 32 are formed by bending the vicinity of both ends of the bottom portion 31 in the head width direction, and protrude upward from both ends of the bottom portion 31 in the width direction. The reinforcing member 30 has a U-shaped cross section perpendicular to the longitudinal direction of the head, and the bending rigidity in the longitudinal direction of the head is larger than that of the holder 20. With such a reinforcing member 30, the bending rigidity in the head longitudinal direction of the head 10 and the holder 20 is reinforced. The reinforcing member 30 and the holder 20 are connected via the point contact portions on the protrusions 21p and 23p of the holder 20 described above.

  As described above, the bottom 31 is formed with five through holes 31x through which the shaft 23 of the holder 20 is inserted so as to form a line along the longitudinal direction of the head (see FIG. 4B). The peripheral edge of the through hole 31 x on the upper surface of the bottom portion 31 is supported by the caulking portion 23 b of the shaft 23.

  As shown in FIGS. 6 and 7, a driver IC 45 is in contact with the outer surface of the upper end of the protruding portion 32. The driver IC 45 is provided for each of the eight actuator units 17 of the head 10. Four driver ICs 45 are in contact with each protrusion 32 at equal intervals in the head longitudinal direction, and an opening 30x extending in the head longitudinal direction below the contact position of each driver IC 45 (FIGS. 5 and 6). And FIG. 7). The length of the opening 30x in the longitudinal direction of the head is substantially the same as or slightly larger than that of the driver IC 45. The reinforcing member 30 functions as a heat sink that dissipates heat generated in the driver IC 45.

  As described above, according to the head unit 1 according to the present embodiment, the bending strength in the head longitudinal direction of the head 10 and the holder 20 is reinforced by the reinforcing member 30, thereby depending on the load factor (the own weight of the head 10). In addition, it is possible to suppress bending of the head 10 in the longitudinal direction (due to a load applied to the head 10 when the head unit 1 is assembled in the housing 501a of the printer 500). Moreover, the reinforcing member 30 is connected to the holder 20 via point contact portions at the protrusions 21p and 23p. In this case, the outer peripheral surface of the shaft main body 23 a in the holder 20 and the side wall defining the through hole 31 x in the reinforcing member 30 are in direct contact (surface contact) without a gap, or the upper surface of the support plate 21 of the holder 20 and the reinforcing member 30. Compared with the case where the lower surface of the bottom portion 31 is in direct contact (surface contact) with no gap, heat transfer from the reinforcing member 30 to the holder 20 and further to the head 10 is suppressed, and the longitudinal direction of the head 10 due to thermal factors. Can be suppressed. Therefore, according to the present embodiment, the deflection of the head 10 can be suppressed from both the load factor and the thermal factor.

  The reinforcing member 30 functions as a heat sink for the driver IC 45. That is, according to the present embodiment, by using a heat sink generally provided in the head unit as the reinforcing member 30, the above effects can be obtained with a simple configuration without adding the number of components.

  The support plate 21 of the holder 20 is sandwiched between the head 10 and the reinforcing member 30. Thereby, the reinforcement improvement of the holder 20 and by extension, the reinforcement improvement of the head 10 are implement | achieved.

  With the simple configuration of the protrusions 21p and 23p, point contact between the holder 20 and the reinforcing member 30 is realized, and the thermal resistance between the holder 20 and the reinforcing member 30 connected to each other can be improved.

  The protrusions 21p form two rows along the head longitudinal direction on the upper surface of the support plate 21 of the holder 20. Thereby, the holder 20 and the reinforcing member 30 can be uniformly connected over the longitudinal direction of the head.

  Since the cross section orthogonal to the longitudinal direction of the head in the reinforcing member 30 is U-shaped, the structural strength of the reinforcing member 30 is increased, and the reinforcing effect of the reinforcing member 30 can be improved.

  A driver IC 45 is attached to the outer surface of the protrusion 32 in the reinforcing member 30. In this case, compared with the case where the driver IC 45 is attached to the bottom 31 of the reinforcing member 30, the heat generated in the driver IC 45 is less likely to be transmitted from the reinforcing member 30 to the holder 20 and the head 10. Further, compared to the case where the driver IC 45 is attached to the inner surface of the protruding portion 31, the heat generated in the driver IC 45 is easily dissipated to the outside, and heat transfer to the holder 20 and the head 10 can be suppressed.

  A driver IC 45 is attached to the upper end of the protruding portion 31 of the reinforcing member 30. As a result, the distance between the driver IC 45 and the holder 20 becomes relatively long, so that heat generated in the driver IC 45 is difficult to be transmitted from the reinforcing member 30 to the holder 20 and the head 10.

  The reinforcing member 30 is provided with an opening 30x at a position closer to the holder 20 than a position where the driver IC 45 is attached. The opening 30x improves the thermal resistance of the reinforcing member 30 and makes it difficult for heat generated in the driver IC 45 to be transmitted from the reinforcing member 30 to the holder 20 and the head 10.

  Next, an inkjet head unit 101 as a second embodiment of the droplet discharge device according to the present invention will be described with reference to FIG.

  In the head unit 101 of this embodiment, 1-4 of the five shafts 23 (see FIG. 4B) of the holder 20 in the head unit 1 according to the first embodiment are replaced with the shaft 123 shown in FIG. Other configurations are the same as those of the head unit 1 of the first embodiment. The shaft 123 is obtained by removing the protrusion 23p from the shaft 23 according to the first embodiment. Projections 21p are not provided on both sides of the shaft 123 in the head width direction. A cylindrical heat insulating collar 124 is attached to the shaft main body 23 a of the shaft 123. The heat insulating collar 124 is made of a material having a lower thermal conductivity than the reinforcing member 30 and the holder 20 such as ceramic. The heat insulating collar 124 is disposed so as to fill a gap between the shaft main body 23 a and the through hole 31 x, and is sandwiched between the shaft main body 23 a of the holder 20 and a side wall that defines the through hole 31 x in the bottom 31 of the reinforcing member 30. Has been. The heat insulating collar 124 extends in the outer peripheral direction at the lower end and is in contact with the upper surface of the support plate 21 of the holder 20.

  As described above, according to the head unit 101 according to the present embodiment, the reinforcing member 30 and the holder 20 are shown in FIG. 11 in addition to the point contact portions formed by the projections 23 and the projections 21p of the shaft 23 shown in FIG. Such a heat insulating collar 124 is also connected to each other by a connecting portion sandwiched between the reinforcing member 30 and the holder 20. Therefore, the connection between the reinforcing member 30 and the holder 20 is strengthened. Moreover, since the heat insulating collar 124 having a low thermal conductivity is sandwiched between the reinforcing member 30 and the holder 20 at the connecting portion, the heat transfer from the reinforcing member 30 to the holder 20 and further to the head 10 is suppressed while being reinforced. The connection between the member 30 and the holder 20 can be strengthened.

  The ink jet head unit according to the above-described embodiment is one in which the adjacent member is thermally isolated from the heat generating member by interposing a high-resistance heat element between the heat generating member and the adjacent member adjacent to the heat generating member. is there. Specifically, a head that discharges droplets, a resin holder (adjacent member) that supports the head, a metal reinforcing member (heat generating member) that is thermally coupled to a driver IC that generates heat when driven, and a reinforcing member In the laminated body in which the base portion supporting the control board disposed above is laminated in order from the bottom, the reinforcing member (heat generating member) is provided via the protrusion 21p, the protrusion 23p, the heat insulation collar 124, etc. (thermal high resistance body). And a holder (adjacent member). In particular, when the adjacent member is a member having a high coefficient of thermal expansion or a composite of materials having different coefficients of thermal expansion, adverse effects are likely to occur on the dimensional change of the adjacent member due to thermal effects. The harmful effect can be suppressed by the intervention of the high-resistance resistor of heat. Further, in the case of suppressing the thermal effect on the adjacent member without interposing a high resistance body of heat, it is necessary to increase the distance between the adjacent member and the heating member, but according to the above-described embodiment, There is no need to increase the distance, and the head unit can be downsized.

  Further, in the inkjet head unit according to the above-described embodiment, a part of the laminated body including the head, the holder, and the like is covered with the cover. Specifically, the head unit has a box-shaped cover that is open on one side, the cover is fixed on the holder, and a driver IC, a reinforcing member, and a cover are formed in the space formed by the cover and the holder. The base is housed. As a result, entry of liquid mist from the outside is prevented, and electrical problems such as a short circuit can be avoided. In addition, when the head unit is incorporated in the printer, the cover is positioned at the upper end of the head unit in the vertical direction, and the heat of the driver IC and the reinforcing member is removed from the slit-like vents provided in the upper wall of the cover. Then, the ink is discharged to the outside in the direction opposite to the head (upward). Thus, according to the head unit according to the above-described embodiment, even if a cover that covers an electrical component such as a driver IC or a reinforcing member is provided as a countermeasure against mist, the conduction of heat to the holder (adjacent member) can be performed. It is configured to be suppressed as much as possible.

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

  For example, the driver IC 54 may be attached to the inner surface of the protrusion 32 of the reinforcing member 30 or may be attached near the lower end of the protrusion 32. Further, the opening 30x of the reinforcing member 30 may be omitted.

  The reinforcing member is not limited to having a U-shaped cross section, and may have various shapes such as a flat plate shape without the protruding portion 32 of the above-described embodiment.

  Regarding the reinforcing member, the holder, and the head, in the above-described embodiment, the reinforcing member is made of metal, the holder is made of resin, and the head is made of a metal plate or the like. However, the constituent materials are not particularly limited. The reinforcing member only needs to have a structural strength that can reinforce the head and the holder and has a relatively high thermal conductivity. The relationship between the reinforcing member and the holder only needs to have a high thermal resistance between them.

  The protrusions 21p of the holder 20 form two rows along the longitudinal direction of the head in the above-described embodiment, but may form three or more rows.

  The positions and shapes of the protrusions 21p and 23p are not particularly limited as long as the point contact between the reinforcing member and the holder is realized.

  The reinforcing member and the holder may be coupled by line contact or the like in addition to the plurality of point contact portions. For example, in the first embodiment, one to four of the five shafts 23 (see FIG. 4B) of the holder 20 may be configured as follows. That is, a plurality of convex portions extending in the axial direction and projecting outward (radially) are provided on the outer peripheral surface of the shaft main body 23a of the shaft 23, and the reinforcing member and A holder may be connected. Here, when the convex portion has a shape that tapers outward in a plane orthogonal to the shaft 23, when the line portion is in line contact with the inner wall of the through hole 31, although not as point contact, Thermal resistance can be increased. As a result, heat transfer from the reinforcing member to the holder and further to the head is suppressed, and problems due to differences in the coefficient of thermal expansion between the members can be reduced.

  In the second embodiment, one protrusion 21p of the first embodiment may be provided on each side of the shaft 123 in the head width direction. Thereby, the support of the reinforcing member 30 by the holder 20 can be further stabilized.

  The holder may not be sandwiched between the head and the reinforcing member.

  The drive circuit may not be attached to the reinforcing member. That is, the reinforcing member does not function as a heat sink for the drive circuit, and may be another member other than the heat sink.

  The head is not limited to the one including the reservoir unit 11 and the flow path unit 10 as in the above-described embodiment, and may have various other configurations.

  In the above-described embodiment, the head longitudinal end 20c (see FIG. 2B) of the holder 20 is fixed to the positioning member (the head frame 503 fixed to the recording apparatus main body). A protrusion protruding from the one end 20c may be formed on the protrusion, and the protrusion of the reinforcing member may be fixed to the positioning member. In this case, when the protruding portion of the reinforcing member is exposed to the outside of the cover 2, the heat dissipation action by the reinforcing member is promoted, and the above-described effect (effect of suppressing heat transfer to the holder and the head) is also improved. Further, when fixing the protruding portion of the reinforcing member to the positioning member, the reinforcing member and the holder are positioned by a plurality of pins spaced apart from each other along the head longitudinal direction, and the pin hole close to the positioning member is circular, The pin hole spaced apart from the positioning member may have an oblong shape elongated in the longitudinal direction of the head. In this case, the change in the nozzle position of the head accompanying the temperature rise of the reinforcing member can be mitigated.

  As the positioning member, a head frame fixed to the recording apparatus main body is illustrated. However, in the case of a serial type in which the head is reciprocated in the width direction of the recording medium while being held by the carriage in the recording apparatus, the carriage corresponds to the positioning member. To do.

  A heat insulating washer or the like may be interposed between the crimping portion 23 b and the upper surface of the bottom portion 31.

  The liquid droplet ejection apparatus according to the present invention can be applied to both a line type and a serial type, and is not limited to a printer, and can also be applied to a recording apparatus such as a facsimile or a copying machine. Further, it may eject droplets other than ink droplets.

1: 101 Inkjet head unit (droplet discharge device)
10 Inkjet head (droplet discharge head)
10x discharge surface 17 Actuator unit 18 Nozzle 20 Holder 20c One end 21p, 23p in the longitudinal direction of the holder Projection 30 Reinforcement member 31 Bottom 32 Projection 40 Flexible printed circuit board 45 Driver IC (drive circuit)
124 Thermal insulation collar (member with low thermal conductivity)
500 Inkjet printer 503 Head frame (positioning member)

Claims (14)

A droplet discharge head having a plurality of nozzles for discharging droplets and a plurality of actuators respectively corresponding to the nozzles;
A holder for supporting the droplet discharge head along the longitudinal direction of the droplet discharge head;
A reinforcing member connected to the holder via a plurality of point contact portions arranged separately along the longitudinal direction, and having a bending rigidity in the longitudinal direction larger than that of the holder;
The droplet discharge apparatus, wherein the droplet discharge head is fixed to the holder by a fixing member while being separated from the holder via a gap on the side opposite to the reinforcing member with respect to the holder .   2. The droplet discharge device according to claim 1, wherein the gap is sandwiched between the plurality of fixing members in a direction parallel to a surface facing the droplet discharge head in the holder while being separated from the droplet discharge head. . The holder is sandwiched between the droplet discharge head and the reinforcing member;
The said point contact part is formed of the some protrusion protruded in the direction approaching the said reinforcement member from the surface which spaced apart and opposed to the said reinforcement member in the said holder, The Claim 1 or 2 characterized by the above-mentioned. Droplet discharge device.   The droplet discharge device according to claim 3, wherein the protrusion forms a plurality of rows along the longitudinal direction on the surface of the holder. The holder protrudes from the surface of the holder in a direction approaching the reinforcing member, and is provided at an end of the shaft main body that is inserted through the reinforcing member, and in an end portion of the shaft main body that approaches the reinforcing member. And a caulking portion that supports a surface of the reinforcing member opposite to the surface facing the holder,
The protrusion supports a surface of the reinforcing member facing the holder;
5. The droplet discharge device according to claim 3, wherein the reinforcing member and the holder are connected to each other by the point contact portion formed by the protrusion and the caulking portion.   The droplet discharge device according to claim 5, wherein the protrusions are arranged in a symmetrical positional relationship around the shaft main body on the surface of the holder. A plurality of the caulking portions are arranged along the longitudinal direction to form one row,
7. The droplet discharge device according to claim 5, wherein one protrusion is disposed on each side of the shaft main body with respect to a direction orthogonal to the longitudinal direction.   In addition to the point contact portion, the reinforcing member and the holder are connected to each other by a connecting portion sandwiched between the reinforcing member and the holder, and a member having a lower thermal conductivity than the reinforcing member and the holder. The liquid droplet ejection apparatus according to claim 1, wherein the liquid droplet ejection apparatus is a liquid ejection apparatus. The reinforcing member includes a bottom portion facing the holder, and a protruding portion protruding in a direction intersecting the bottom portion from an end portion of the bottom portion,
The liquid droplet ejection apparatus according to claim 1, wherein a driving circuit that outputs a driving signal to the actuator is attached to an outer surface of the protruding portion.   The droplet discharge device according to claim 9, wherein a drive circuit that outputs a drive signal to the actuator is attached to an end portion of the projecting portion that is separated from the holder.   11. The droplet discharge device according to claim 9, wherein the reinforcing member includes two protrusions, and a cross section intersecting the longitudinal direction is U-shaped.   2. The reinforcing member has an opening extending in the longitudinal direction at a position closer to the holder than a position at which a drive circuit that outputs a drive signal to the actuator is attached. The droplet discharge apparatus according to any one of to 11. A line-type inkjet head having a plurality of nozzles for ejecting ink droplets and a plurality of piezoelectric actuators respectively corresponding to the nozzles;
A driver IC that outputs a drive signal to the actuator;
A holder for supporting the inkjet head along the longitudinal direction of the inkjet head, the holder having a flat support plate extending in the longitudinal direction;
A heat sink for the driver IC, comprising: a heat sink having a bending rigidity in the longitudinal direction larger than that of the holder;
The inkjet head is fixed to the support plate by a fixing member while being separated from the support plate via a gap on one surface side of the support plate,
The gap is sandwiched between the plurality of fixing members in a direction parallel to the one surface,
The heat sink is connected to the support plate via a plurality of point contact portions arranged along the longitudinal direction on the other surface side of the support plate;
The droplet discharge device, wherein the point contact portion is formed by a plurality of protrusions protruding in a direction approaching the heat sink from the other surface. The heat sink includes a bottom portion facing the support plate, and a protruding portion protruding in a direction intersecting the bottom portion from an end portion of the bottom portion,
The driver IC is attached to the outer surface of the protrusion;
The droplet discharge device according to claim 13, wherein the heat sink has an opening extending in the longitudinal direction at a position closer to the support plate than a position where the driver IC is attached.

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