JP2012213884A - Liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently discharge air flowing into grooves during purge while suppressing the flow of an adhesive applied to a flow passage into a hole or a recess by the grooves.SOLUTION: A release groove group 174 is formed on an upper wall face of a common ink flow passage formed between an outlet opening 151 and a plurality of ink supply ports 115a. The release groove group 174 is constituted of four release grooves 174a, 174b, 174c, 174d. A contour line of the release groove 174a is substantially in parallel with a sidewall face defining a manifold flow passage 105 which is a boundary between a bonding region 161 and a non-bonding region 162. A formation range related to an auxiliary scanning direction of the release groove group 174 includes a formation range related to an auxiliary scanning direction of the outlet opening 151 and the plurality of ink supply ports 115a. Each contour line of the four release grooves 174a, 174b, 174c, 174d is formed of only a parallel portion parallel with a tangential direction in a position corresponding to each release groove of a flow line R of ink.

Description

  The present invention relates to a liquid ejection head having a flow path unit formed by laminating a plurality of plates in which through holes are formed via an adhesive.

  2. Related Art An ink jet head having a flow path unit formed by laminating a plurality of plates with through-holes via an adhesive is known. In such an inkjet head, in order to prevent the adhesive applied to each plate from flowing into a hole or a recess provided in each plate during manufacture, the adhesive relief groove is formed in the adhesive region with the adjacent plate. May be provided. Furthermore, in the ink jet disclosed in Patent Document 1, in order to prevent the adhesive applied to the non-adhesion area not bonded to the adjacent plate from flowing into the hole or the recess, not only the adhesion area but also the non-adhesion area. An escape groove is provided.

JP 2005-59410 A

  Since the non-adhesion region of the plate serves as a wall surface that defines the ink flow path, when a relief groove is provided in the non-adhesion region as in Patent Document 1, the air that has been present in the liquid with the passage of time is removed. There is a possibility that air bubbles will inevitably accumulate in the escape groove and hinder ink ejection. For this reason, it is necessary to periodically perform a purge operation to discharge air from the head. However, in order to discharge the air that has fallen into the escape groove, it is necessary to lengthen the purge time or increase the purge pressure, and there is a problem that the amount of ink discarded during the purge increases.

  Accordingly, an object of the present invention is to efficiently discharge air that has fallen into the groove during purging while suppressing the adhesive applied to the liquid flow path from flowing into the hole or the recess. It is to provide a liquid discharge head.

  The liquid discharge head according to the present invention includes a first flow path in which a liquid is supplied through a first port by laminating a plurality of plates in which through holes are formed via an adhesive, and the first port. A liquid discharge head having a flow path unit in which a second flow path connected to the first flow path is formed through a second port formed in the same plate as the first port and the first flow path One or a plurality of grooves are formed in the wall surface facing the first flow path of the plate in which two openings are formed, and the formation range of the one or more grooves is in one direction in the plate surface. A range of formation of the first port is included, and an outline of at least one groove in the one or more grooves is configured so that the liquid from the first port to the second port in the first flow path Having a parallel part parallel to the tangential direction at a position corresponding to the outline of the flow line When there is a non-parallel portion that is not parallel to a tangential direction at a position corresponding to the outer shape line of the flow line on the outer shape line of the one or more grooves, the non-parallel portion is connected to the parallel portion. At the same time, the upstream area of the non-parallel portion with respect to the connection location and the downstream area of the parallel portion with respect to the connection location are connected to form an obtuse angle.

  In the present invention, the “parallel portion” is not intended only to make 0 ° with respect to the tangential direction of the flow line, but at an angle that does not significantly hinder the movement of air in the groove. It is intended to include what is being done.

  According to the present invention, the flow of air in the groove can be made smooth while the flow of the adhesive into the first port during application of the adhesive is suppressed by the groove. Therefore, air can be efficiently discharged to the outside through the first flow path and the second flow path at the time of purging.

It is the schematic which shows the internal structure of the ink jet type printer containing the ink jet head which concerns on one Embodiment of this invention. FIG. 2 is a plan view of a head body of an inkjet head included in the printer shown in FIG. 1. FIG. 3 is an enlarged view of a region III surrounded by an alternate long and short dash line in FIG. 2. FIG. 4 is a partial cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5A is an enlarged cross-sectional view of a region VA surrounded by an alternate long and short dash line in FIG. 3, and FIG. 5B is a partial plan view of the actuator unit viewed from the direction of arrow VB in FIG. It is a partial bottom view of the supply plate contained in a flow path unit in one embodiment of the present invention. FIG. 5 is a schematic diagram showing ink flow lines in a manifold channel as a common ink channel provided in a channel unit. It is drawing which shows the relationship between the shape of the outline of an escape groove, and the flow line of an ink. It is a partial bottom view of a supply plate of a channel unit in a modification. It is the schematic diagram which drawn the shape of the outline of the escape groove in one modification.

  First, an overall configuration of an ink jet printer 101 including an ink jet head (liquid ejection head) according to an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the printer 101 has a rectangular parallelepiped casing 101a. A paper discharge recess (paper discharge unit) 15 is provided on the top surface of the casing 101a. The space inside the housing 101a is divided into an upper space, a middle space, and a lower space. In the upper space, image formation on the paper P and conveyance of the paper P to the paper discharge recess 15 are performed. In the middle space, the paper P is stored and carried out. Between the upper space and the middle space, a sheet conveyance path (path along the thick arrow in FIG. 1) from the sheet storage section to the sheet discharge recess 15 is formed. The lower space is isolated from the upper space and the middle section, and ink is stored and supplied.

  In the upper space, five inkjet heads 1a, 1b, 1c, 1d, and 1e (which may be simply referred to as the head 1 when they need not be distinguished from each other), a transport mechanism 16 that transports the paper P, and the paper P A guide portion for guiding the control, a control device 100, and the like are disposed.

  The five heads 1 eject colorless pretreatment liquid (P), yellow ink (Y), magenta ink (M), cyan ink (C), and black ink (B), respectively. The head 1a that discharges the pretreatment liquid is at the most upstream in the paper transport direction. The five heads 1 have the same structure, are arranged at a predetermined pitch in the transport direction, and are fixed to the frame-like frame 3. The frame 3 is supported so as to be movable relative to the housing 101a.

  As shown in FIG. 1, the transport mechanism 16 includes, in addition to the belt rollers 6 and 7 and the transport belt 8, a nip roller 4 and a peeling plate 5 disposed outside the transport belt 8, and a platen disposed inside the transport belt 8. 18 and a tension roller 10.

  The conveyor belt 8 is an endless belt wound between the rollers 6 and 7 and receives a downward tension by the tension roller 10. The platen 18 is a flat plate disposed facing the five heads 1 and supports the loop upper portion of the conveyor belt 8 from the inside. The belt roller 7 is a driving roller and rotates by the rotational force of the transport motor 7M. The rotational force is transmitted through a plurality of gears. The belt roller 7 rotates clockwise in FIG. 1, and the conveyor belt 8 runs in the direction of the arrow. The belt roller 6 is a driven roller and rotates as the conveyor belt 8 travels. The nip roller 6 is disposed to face the belt roller 6 and presses the paper P against the transport belt 8. A weak adhesive silicon layer is formed on the outer peripheral surface of the conveyor belt 8, and the paper P is held on the outer peripheral surface. The peeling plate 5 is disposed so as to face the belt roller 7, peels the paper P from the transport belt 8, and guides the paper P to the subsequent guide portion.

  The guide part is composed of an upstream guide part and a downstream guide part in the transport direction. The upstream guide portion and the downstream guide portion sandwich the transport mechanism 16 from both sides in the transport direction. The upstream guide portion includes guides 13 a and 13 b and a feed roller pair 14, and connects the paper feed unit 101 b and the transport mechanism 16. The image forming paper P is transported toward the transport mechanism 16. The downstream guide includes guides 29 a and 29 b and two feed roller pairs 28, and connects the transport mechanism 16 and the paper discharge recess 15. The paper P after image formation is conveyed toward the paper discharge recess 15.

  In the upper space, the control device 100 is disposed on the bottom surface of the top plate of the housing 101a. The control device 100 governs the overall operation of the printer 101. The control device 100 controls the liquid ejection operation synchronized with the carry-out, transport, discharge, and transport of the paper P based on the print command received from the external device. When the paper P is fed out from the paper supply unit 101 b and passes under the five heads 1, the pretreatment liquid and ink are sequentially ejected from each head 1, and an image is formed on the paper P. The ejection operation from each head 1 is performed based on a paper leading edge detection signal from the paper sensor 32. The paper sensor 32 is on the upstream side in the transport direction of the head 1a. Further, the paper P is discharged from the discharge port 30 to the paper discharge recess 15.

  A paper feeding unit 101b is disposed in the middle space. The paper feed unit 101 b includes a paper feed tray 11 and a paper feed roller 12. The paper feed tray 11 is a box that is detachable from the housing 101a and opens upward. A plurality of sheets P are stored in the sheet feed tray 11, and the sheet feed roller 12 feeds the uppermost sheet P.

  A tank unit 101c is disposed in the lower space. The tank unit 101c is detachable from the housing 101a, and five tanks 17a, 17b, 17c, 17d, and 17e (may be simply referred to as the tank 17 when there is no need to distinguish each other) are disposed. ing. A pretreatment liquid is accommodated in the tank 17a. The tanks 17b, 17c, 17d, and 17e contain yellow ink, yellow ink, magenta ink, cyan ink, and black ink, respectively. Each tank 17 is connected to the corresponding head 1 via a tube (not shown).

  The pre-treatment liquid, for example, has a density improving effect (an effect of improving the density of ink landed on the paper P), an ink bleeding or back-through (the ink landed on the paper P penetrates the layer of the paper P and oozes on the back surface) A colorless liquid having an effect of preventing the occurrence of phenomenon), an effect of improving the color developability and quick drying of the ink, and an effect of suppressing wrinkles and curling of the paper P after ink landing. The material of the pretreatment liquid can be appropriately selected from a liquid containing a polyvalent metal salt such as a cationic polymer or a magnesium salt. The pretreatment liquid discharged from the head 1a lands on the paper P before the ink discharged from the heads 1b to 1e.

  Next, the head 1 will be described with reference to FIGS. In FIG. 3, the actuator unit 21 to be drawn with a solid line is drawn with a two-dot chain line, and the aperture 112 to be drawn with a broken line is drawn with a solid line.

  Each head 1 is a line-type head that is long in the main scanning direction (direction orthogonal to the transport direction), and is a laminated body in which a head main body 2, a liquid distribution member, a circuit board, and the like are laminated. The liquid distribution member evenly distributes the liquid supplied from the tank 17 to the head body 2. The circuit board adjusts a control signal from the control device 100 and supplies it to the actuator unit 21. The actuator unit 21 and the circuit board are electrically connected by a COF (Chip On Film) on which a driver IC is mounted.

  The head body 2 includes a flow path unit 9 that is long in the main scanning direction, and four actuator units 21 that are fixed to the upper surface 9 a of the flow path unit 9.

  As shown in FIG. 4, the flow path unit 9 is a conductive laminated body in which nine stainless steel metal plates 122, 123, 124, 125, 126, 127, 128, 129 and 130 are laminated.

  As shown in FIG. 2, the upper surface 9a of the flow path unit 9 has a plurality of pressure chambers 110, two inflow ports 105b, and four inflow ports 105c that are longer in the main scanning direction than the inflow ports 105b. is doing. The four inflow ports 105 c are provided between the two inflow ports 105 b in the longitudinal direction of the flow path unit 9. The liquid supplied from the above-described liquid distribution member flows into the inflow ports 105b and 105c. Inside the flow path unit 9, an inflow flow path extending in the vertical direction with the respective inlets 105b and 105c as inlets is formed. The inflow channel is configured by connecting through holes formed in the four plates 122 to 125. Further, as shown in FIGS. 3 and 4, the flow path unit 9 includes a manifold flow path (first flow path) 105 as a common ink flow path connected to the inflow flow path, and a manifold flow path 105. A plurality of sub-manifold channels (first channels) 105a that branch and extend in the main scanning direction, and the outlets of the sub-manifold channels 105a to the discharge ports 108 via the pressure chambers 110. A plurality of individual ink flow paths (second flow paths) 132 are formed.

  As shown in FIG. 4, the pressure chamber 110 is connected to the sub-manifold channel 105 a via an aperture (throttle portion) 112. The lower surface of the flow path unit 9 is a discharge surface 2a that discharges liquid. A plurality of discharge ports 108 are two-dimensionally arranged on the discharge surface 2a so as to be arranged at equal intervals in the main scanning direction. The individual ink channel 132 extends upward from the ink supply port (second port) 115a that is the outlet of the sub-manifold channel 105a, extends horizontally at the aperture 112, and then further upwards, and again at the pressure chamber 110. It extends horizontally, and then heads diagonally downward in a direction away from the aperture 112 for a while and then heads downward toward the discharge port 108 vertically.

  Each actuator unit 21 has a trapezoidal planar shape as shown in FIG. The four actuator units 21 are arranged in two rows in a staggered manner in the main scanning direction. Specifically, the first and third actuator units 21 from the end of the four are such that the lower base of the trapezoid is closer to one long side of the channel unit 9 having a rectangular shape in plan view than the upper base, The second and fourth actuator units 21 from the end are arranged so that the lower base is closer to the other longer side than the upper base. The two opposite hypotenuses of the two adjacent actuator units 21 have overlapping positions in the main scanning direction for the most part. The inflow port 105 c is provided for each actuator unit 21 and extends in parallel with the upper base of the corresponding actuator unit 21.

  The actuator unit 21 is made of a lead zirconate titanate (PZT) ceramic material having ferroelectricity, and includes three piezoelectric layers 141, 142, and 143 as shown in FIG. The piezoelectric layers 141 to 143 have the same shape and size, and define the outer shape of the actuator unit 21. Only the piezoelectric layer 141 is provided with electrodes on the upper and lower surfaces (individual electrodes 135 on the upper surface and common electrode 134 on the lower surface). As shown in FIG. 5B, the individual electrode 135 has a substantially rhombic planar shape similar to the pressure chamber 110. The main part of the individual electrode 135 faces the pressure chamber 110, and one acute angle portion of the rhombus extends outside the pressure chamber 110. A circular land 136 is formed at the tip in the extending direction in a plan view. The common electrode 134 is sandwiched between two piezoelectric layers 141 and 142, and is formed on almost the entire lower surface of the piezoelectric layer 141 (the upper surface of the piezoelectric layer 142). The lower surface of the piezoelectric layer 143 is fixed to the upper surface 9 a of the flow path unit 9 and seals the opening of the pressure chamber 110. A common electrode land (not shown) electrically connected to the common electrode 134 is also formed on the upper surface of the piezoelectric layer 141. A drive signal is selectively applied to the land for individual electrode 136, and a ground potential of a reference potential is applied to the land for common electrode.

  Only the piezoelectric layer 141 is polarized and functions as an active layer. When a polarization direction electric field is applied to a portion sandwiched between the individual electrode 135 and the common electrode 134 in the piezoelectric layer 141, piezoelectric distortion in the plane direction (displacement in the vibration mode of d31) occurs. On the other hand, no spontaneous displacement occurs in the piezoelectric layers 142 and 143. At this time, a difference in distortion occurs in the plane direction between the piezoelectric layer 141 and the piezoelectric layers 142 and 143, so that a portion of the piezoelectric layers 141 to 143 sandwiched between the individual electrode 135 and the pressure chamber 110 is a surface. Deformation (unimorph deformation) in a direction orthogonal to the direction changes the volume of the pressure chamber 110. That is, the portion sandwiched between the individual electrode 135 and the pressure chamber 110 in the actuator unit 21 functions as a piezoelectric actuator that applies discharge energy from the discharge port 108 to the liquid in the pressure chamber 110. That is, the same number of piezoelectric actuators as the pressure chambers 110 are built in the actuator unit 21. Each piezoelectric actuator can be deformed independently of each other. In this embodiment, when a drive signal is supplied from the driver IC to the individual electrode 135, the piezoelectric actuator is deformed so as to protrude toward the pressure chamber 110, and the volume of the pressure chamber 110 is reduced. Thus, pressure (discharge energy) is applied to the liquid in the pressure chamber 110, and the liquid is discharged from the discharge port 108.

  In the process of manufacturing the inkjet head 1, the plurality of plates 122 to 130 constituting the actuator unit 21 and the flow path unit 9 are bonded and laminated with an adhesive. That is, the adhesive is transferred along the one direction (in the present embodiment, along the direction parallel to the longitudinal direction of the flow path unit 9) by a roll coater, a bar coater or the like over the entire area of one surface of each plate. After that, another plate to be bonded to the plate is attached. At this time, in order to prevent the adhesive from flowing into holes or recesses (only holes exist in this embodiment) that are respectively formed in the plates 122 to 130 and constitute a part of the individual ink flow path 132. In addition, a plurality of escape grooves into which excess adhesive flows are formed by half-etching on the bonding surfaces of two adjacent plates to be stacked.

  Here, among the plurality of plates 122 to 130, the supply plate 125 constituting the upper walls of the manifold channel 105 and the sub-manifold channel 105a will be described with reference to FIG. FIG. 6 is a partial bottom view of the supply plate 125 and shows a part of the back surface (lower surface) of the supply plate 125 facing the same direction as the ejection surface 2a. 2 and 3 show an example in which one manifold channel 105 is branched into four sub-manifold channels 105a extending in the main scanning direction. However, in order to simplify the explanation, FIG. 6 shows an example in which one manifold channel 105 is connected to only one sub-manifold channel 105a extending in the main scanning direction without branching. In the example of FIG. 6, the plurality of pressure chambers 110 connected to the sub-manifold flow path 105 a constitute four pressure chamber rows that respectively extend in the longitudinal direction of the flow path unit 9.

  The supply plate 125 is provided with a through hole constituting the lower end region of the inflow channel and its outlet opening 151 (first port: see FIG. 6). Further, as shown in FIG. 4, the supply plate 125 constitutes a part of the individual ink flow path 132, a plurality of ink supply holes 115 for communicating the sub manifold flow path 105 a and the aperture 112, and the same individual ink. A plurality of communication holes 114 that constitute a part of the flow path 132 and communicate with the pressure chamber 110 and the discharge port 108 are formed. The plurality of communication holes 114 not shown in FIG. 6 are arranged in the longitudinal direction of the flow path unit 9 so that the planar positional relationship with the sub-manifold flow path 105a is substantially the same as the discharge port 108 shown in FIG. Each of the four communication hole rows extends. The plurality of ink supply ports 115a provided at the lower ends of the plurality of ink supply holes 115 extend in the longitudinal direction of the flow path unit 9 so as to face the sub-manifold flow path 105a, as shown in FIG. Four supply port arrays are formed.

  A region including the plurality of communication holes 114 and not including the outlet opening 151 and the plurality of ink supply holes 115 is a bonding region 161 that is bonded to the plate 126 adjacent to the lower side by an adhesive. Therefore, the adhesive region 161 has a plurality of annular reliefs individually surrounding the communication holes 114 in order to prevent excess adhesive from flowing into the communication holes 114 when applying the adhesive and laminating / pressing the plates. A groove 170 (see FIG. 4, not shown in FIG. 6) is formed.

  Three inner encircling grooves 171 and three outer encircling grooves 172 are formed in the adhesion region 161 and in the vicinity of the boundary with the non-adhesion region 162 that is not adhered to the lower adjacent plate 126, respectively. Yes. The inner surrounding groove 171 and the outer surrounding groove 172 have a function of suppressing excess adhesive from flowing into the outlet opening 151 and the plurality of ink supply ports 115a, as in the escape groove group 174 described later. An annular region surrounded by the three inner surrounding grooves 171 and the three outer surrounding grooves 172, both of which are annular, is a non-adhesive region 162 in which the outlet opening 151 and the plurality of ink supply ports 115a are formed. In the example shown in FIG. 6, the non-adhesive region 162 has a symmetrical shape with respect to an axis S (hereinafter referred to as “symmetric axis”) S extending in the sub-scanning direction through the center of the outlet opening 151 in the main scanning direction. ing.

  In the non-adhesion region 162, a region where the plurality of ink supply ports 115a are provided faces the sub-manifold flow path 105a and extends in the main scanning direction. The region where the plurality of ink supply ports 115a are provided is at a position shifted in the sub-scanning direction from the outlet opening 151, and a part of the plurality of ink supply ports 115a overlaps with the outlet opening 151 in the main scanning direction. . Two regions that connect the outlet opening 151 and both ends of the region in which the plurality of ink supply ports 115 a are provided face the manifold channel 105. The extending direction of these two regions is an oblique direction having components in both the main scanning direction and the sub-scanning direction.

  A lattice groove 173 is formed in the adhesion region 161 to divide the wide adhesion region 161 into a large number of small lattice areas. The lattice grooves 173 have a function of preventing air from remaining on the bonding surface and ensuring reliable bonding between the plates.

  The peripheral portion of the ink supply port 115a is a non-adhesive region 162 that is not bonded to the plate 126 adjacent to the lower side, and it is not necessary to apply an adhesive to this portion. However, since the adhesive is applied to the back surface of the supply plate 125 using a transfer device such as a roll coater or a bar coater, it is efficient to apply the adhesive to the entire back surface of the supply plate 125. In manufacturing the head 1 of this embodiment, the transfer direction of the adhesive is parallel to the longitudinal direction of the flow path unit 9 in consideration of the ease of transfer (from left to right in FIG. 6). ing. At this time, the adhesive flows on the back surface of the supply plate 125 from the upstream side to the downstream side in the transfer direction. However, the adhesive also flows to the non-adhesive region 162 where the adhesive does not need to be applied. There is a possibility that the adhesive may flow into the inflow channel from the opening 151 and into the ink supply hole 115 from the ink supply port 115a.

  Therefore, in the non-adhesion region 162 of the supply plate 125, two release groove groups 174 for releasing the adhesive transferred to the back surface (the upper wall surface of the common ink flow path) of the supply plate 125 are provided. The two escape groove groups 174 have a symmetrical shape with respect to the symmetry axis S. Each escape groove group 174 includes four escape grooves 174a, 174b, 174c, and 174d. The depth of each relief groove is about half or less than the thickness of the supply plate 125. The escape groove 174a is formed in a “C” -shaped curve farthest from the symmetry axis S passing through the outlet opening 151 among the four escape grooves, and has an upstream end in the vicinity of the outlet opening 151 and downstream. The end extends so as to be located in the vicinity of the upstream end of the supply port row farthest from the outlet opening 151. The escape groove 174b is formed in a “U” -shaped curve adjacent to the escape groove 174a, and one end portion is located in the vicinity of the upstream end of the supply port row second from the outlet opening 151, and the other end The portion extends so as to be located in the vicinity of the upstream end of the supply port row that is second closest to the outlet opening 151. The vertex of the “U” shape is located in the vicinity of the outlet opening 151. The escape groove 174c is an annular groove disposed so as to be surrounded by the escape groove 174b. The escape groove 174d is an annular groove disposed so as to be surrounded by the escape groove 174c.

  The outline of the escape groove 174a and the outline of the area closer to the outlet opening 151 with the “U” -shaped apex of the escape groove 174b sandwiched between the adhesive area The side wall surface (the surface defining the through holes formed in the plates 126, 127, and 128) that defines the manifold channel 105 that is the boundary between the 161 and the non-adhesive region 162 is substantially parallel to the side wall surface. Further, the outline of the remaining two escape grooves 174c and 174d and the outline of the area far from the outlet opening 151 across the “U” -shaped apex of the escape groove 174b are in most parts (as a modified example). In the whole area), the closer to the side wall surface that defines the manifold channel 105 that is the boundary between the adhesion region 161 and the non-adhesion region 162, the closer to the shape parallel to the side wall surface, the farther from the side wall surface the It has a shape smaller in curvature than the side wall surface and close to a straight line. The reason for “most part” will be described later.

  The formation ranges of the four relief grooves 174a, 174b, 174c, and 174d in the sub-scanning direction (ranges formed by projecting the relief groove group 174 on the imaginary line extending in the sub-scanning direction from the main scanning direction) The formation range in the sub-scanning direction is included. The formation range of the escape grooves 174a in the sub-scanning direction includes the formation range of all the ink supply ports 115a belonging to the three supply port arrays in the sub-scanning direction. In addition, the formation range related to the sub-scanning direction of the escape groove 174b includes the formation range related to the sub-scanning direction of the ink supply ports 115a belonging to the three supply port arrays closer to the outlet opening 151. Therefore, the release groove group 174 effectively prevents the adhesive applied to the plate 125 from flowing from the outlet opening 151 and the plurality of ink supply ports 115a along the direction from left to right in FIG. Suppress. The effect is remarkable in the escape groove group 174 formed upstream from the symmetry axis S, but it is confirmed that the effect can be obtained in a limited manner in the escape groove group 174 formed downstream from the symmetry axis S. ing.

  In FIG. 7, an ink flow line R in the manifold channel 105 is depicted. The ink that flows into the manifold channel 105 from the outlet opening 151 flows from the outlet opening 151 toward the sub-manifold channel 105 a while being regulated by the shape of the side wall surface that defines the manifold channel 105. As a result, the flow line R in the manifold channel 105 is substantially parallel to the side wall surface in the vicinity of the side wall surface that defines the manifold channel 105, and the curvature is larger than the side wall surface as the distance from the side wall surface increases. Is small and close to a straight line. The ink flow lines in the sub-manifold channel 105a are parallel to the extending direction of the sub-manifold channel 105a (the longitudinal direction of the channel unit 9).

  The relationship between the outlines of the four escape grooves 174a, 174b, 174c, and 174d and the flow line R will be described with reference to FIG. 8 by taking the escape groove 174a as an example. As described above, the outline of the relief groove 174a is parallel to the side wall surface defining the manifold channel 105, which is the boundary between the adhesion region 161 and the non-adhesion region 162, in the most part. In addition, the flow line R passing through the position of the escape groove 174 a is also substantially parallel to the side wall surface that defines the manifold channel 105. That is, the outline of the escape groove 174a and the flow line R are substantially parallel to each other. The “most part” is defined as the vicinity of the upstream end X1 and the downstream end X2 of the relief groove 174a having an acute angle (areas 178, 179, 180, 181 described later: an acute angle with respect to the flow line R). This is because it is excluded.

  As shown in FIG. 8, the outline of the escape groove 174a has two main sections 176 and 177 that are parallel to each other. And the tangent direction in the arbitrary positions of the main areas 176 and 177 is parallel to the tangential direction of the flow line R passing through the positions. For example, the tangential direction D1 at the position X3 of the main section 176 is the tangential direction D2 at the position X4 of the main section 177 (the position closest to the position X3 on the main section 177) and the flow line R passing through the positions X3 and X4. Is parallel to the tangential direction D3. In other words, the main sections 176 and 177 are composed only of parallel portions parallel to the tangential direction at positions (minute regions) corresponding to the main sections 176 and 177 of the flow line R.

  On the other hand, the two linear sections 178 and 179 connected at the upstream end X1 of the escape groove 174a are non-parallel to the tangential direction at the positions (minute regions) corresponding to the sections 178 and 179 of the flow line R. It consists only of parallel parts. The downstream ends of the sections 178 and 179 are connected to the upstream ends of the main sections 176 and 177 so as to form obtuse angles θ1 and θ2, respectively. Similarly, the two linear sections 180 and 181 connected at the downstream end X2 of the escape groove 174a are only from non-parallel portions that are non-parallel to the tangential direction at the positions corresponding to the sections 180 and 181 of the flow line R. Become. The upstream ends of the sections 180 and 181 are connected to the downstream ends of the main sections 176 and 177 so as to form obtuse angles θ3 and θ4, respectively. Regarding the escape grooves 174b, 174c, and 174d, the relationship with the flow line R is the same as that of the escape groove 174a. However, the escape grooves 174c and 174d have only non-parallel portions and only parallel portions.

  As described above, the escape groove group 174 prevents the adhesive flowing from the left to the right in FIG. 6 when the adhesive is applied to the plate 125 from flowing into the flow path from the outlet opening 151 and the plurality of ink supply ports 115a. It has a function of effectively suppressing. However, the air present in the ink becomes bubbles and gradually accumulates in the escape grooves 174a, 174b, 174c, and 174d as time passes. As a result, there is a high possibility that ink ejection is hindered. In order to solve this problem, the printer 101 needs to periodically perform a purge operation that drives a pump (not shown) connected to the head 1 to forcibly discharge the air in the head 1 together with the ink. . In the present embodiment, since the escape groove group 174 has a shape as described in detail with reference to FIG. 8, the air fluidity in each of the escape grooves 174a, 174b, 174c, 174d is increased. . This is because air easily moves along the flow line R in the parallel portion, and the corner portion formed by connecting the parallel portion and the non-parallel portion has an obtuse angle, so that air is accumulated in the corner portion. Because it is difficult. Therefore, the air accumulated in the escape grooves 174a, 174b, 174c, and 174d can be efficiently discharged to the outside from the manifold channel 105 and the plurality of sub-manifold channels 105a via the individual ink channels 132 during the purge. Is possible. Therefore, it is not necessary to make the purge time longer than usual or increase the purge pressure, and the amount of ink discarded during the purge can be minimized.

  Note that the adhesive may flow into the escape grooves 174a, 174b, 174c, and 174d at the time of manufacture, but during purge, air passes over the adhesive flowing into the escape groove and is discharged out of the escape groove. The adhesive that flows into the inside does not hinder the flow of air.

  Further, in the present embodiment, the escape groove 174a of the left-side escape groove group 174 in FIG. 6 is further sub-scanned further upstream than the most upstream (leftmost in FIG. 6) of the plurality of ink supply ports 115a. It is formed so as to include the plurality of ink supply ports 115a with respect to the direction. Therefore, air can be more reliably sent from the ink supply port 115a to the individual ink flow path 132 during purging.

  Furthermore, in this embodiment, the sub-scanning direction is orthogonal to the longitudinal direction of the flow path unit 9, and the sub-manifold flow path 105a provided with a plurality of ink supply ports 115a extends in the main scanning direction. Thereby, the flow of the adhesive into the plurality of ink supply ports 115a can be suppressed while minimizing the length of each of the escape grooves constituting the escape groove group 174. Further, the air that has fallen into the escape grooves 174a, 174b, 174c, and 174d can be effectively discharged during the purge from the plurality of ink supply ports 115a arranged in the ink flow direction D (see FIG. 7).

  In addition, the plurality of ink supply ports 115a are at positions shifted from the outlet openings 151 in the sub-scanning direction, and some of the plurality of ink supply ports 115a are at positions overlapping with the outlet openings 151 in the main scanning direction. The grooves 174a, 174b, 174c, and 174d extend so as to have both a component in the main scanning direction and a component in the sub-scanning direction. Therefore, it is possible to prevent the flow path unit 9 from becoming long while securing the number of discharge ports 108.

  The downstream ends of the non-parallel portions 178 and 179 are connected to the upstream ends of the main portions 176 and 177 that are parallel portions so as to form obtuse angles θ1 and θ2, respectively. This facilitates the delivery of air present along areas 178 and 179 to main areas 176 and 177 which are parallel portions.

  In addition, in this embodiment, the back surface (upper wall surface of the common ink flow path) of the supply plate 125 in which the escape grooves 174a, 174b, 174c, and 174d are formed has the same direction as the discharge surface 2a in which the discharge port 108 is formed. It is suitable. As a result, the air on the back surface of the supply plate 125 to which air easily adheres can be efficiently discharged.

  Further, in the present embodiment, since the escape groove group 174 includes four escape grooves 174a, 174b, 174c, and 174d, the width of each of the escape grooves 174a, 174b, 174c, and 174d can be reduced. Therefore, since the relief groove can be formed relatively easily by half etching or the like, the head 1 can be easily manufactured.

  In addition, in this embodiment, two escape groove groups 174 are provided so as to sandwich the outlet opening 151 in the main scanning direction. Therefore, as described above, entry of the adhesive into the outlet opening 151 can be more effectively suppressed.

  In the present embodiment, as described with reference to FIG. 8, the upstream ends and the downstream ends of the escape grooves 174a and 174b form acute angles, so that air is introduced into the escape grooves and air from the escape grooves. It becomes easy to discharge.

  Next, a modification of the present invention will be described with reference to FIG. FIG. 9 is a partial bottom view showing the back surface of the supply plate, as in FIG. 6. Since this modification has no change from FIG. 6 except for the relief groove formed in the supply plate, the same members as those in the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 9, an outlet opening 151 and a plurality of ink supply ports 115a are opened on the back surface of the supply plate. In the adhesion region 161, three inner surrounding grooves 171, three outer surrounding grooves 172, and lattice grooves 173 are formed.

  In manufacturing the head 1 of this embodiment, the transfer direction of the adhesive is parallel to the longitudinal direction of the flow path unit 9 in consideration of the ease of transfer (from left to right in FIG. 6). . Accordingly, the adhesive flows on the back surface of the supply plate from the upstream side to the downstream side in the transfer direction. However, the adhesive also flows in the non-adhesive region 162 where the adhesive does not need to be applied, and the outlet opening 151 From the ink supply port 115a into the ink supply hole 115.

  Therefore, the two non-adhesive regions 162 of the supply plate are provided with two escape grooves 274 that allow the adhesive transferred to the back surface of the supply plate to escape. The two escape grooves 274 have a symmetrical shape with respect to the symmetry axis S. The width of the escape groove 274 is at least ½ of the maximum width W of the manifold channel 105. The depth of the relief groove 274 is about half or less than the thickness of the supply plate. The escape groove 274 extends so that the upstream end is positioned in the vicinity of the outlet opening 151 and the downstream end is positioned in the vicinity of the upstream ends of the four supply port arrays.

  The outline of the relief groove 274 is considered by dividing it into four areas a, b, c, and d shown in FIG. The area a extends from the upstream end of the escape groove 274 to the left downstream end through the outside. The area b has a linear shape passing from the upstream end of the escape groove 274 to the inside. The section c extends from the downstream end of the section b to the right downstream end. The section d is between the right downstream end and the left downstream end and has a linear shape. Zones a and c are sidewall surfaces (surfaces defining through holes formed in the plates 126, 127, and 128) that define the manifold channel 105 that is a boundary between the bonded region 161 and the non-bonded region 162 in the entire region. And are substantially parallel to each other. Further, the areas b and d are not parallel to the side wall surface defining the manifold channel 105.

  The formation range of the escape groove 274 in the sub-scanning direction (the range formed by projecting the escape groove 274 on the virtual line extending in the sub-scanning direction from the main scanning direction) includes the formation range of the exit opening 151 in the sub-scanning direction. ing. The formation range of the relief groove 274 in the sub-scanning direction includes the formation range of the plurality of ink supply ports 115a in the sub-scanning direction. Accordingly, the release groove 274 effectively suppresses the adhesive applied to the supply plate from flowing from the outlet opening 151 and the plurality of ink supply ports 115a along the direction from left to right in FIG. To do. The effect is remarkable in the escape groove 274 formed upstream from the symmetry axis S, but it is confirmed that the effect can be obtained in a limited manner in the escape groove 274 formed downstream from the symmetry axis S. . In this modification, the ink flow line R in the manifold channel 105 is the same as that described with reference to FIG.

  The relationship between the outline of the escape groove 274 and the flow line R will be described. As described above, the areas a and c of the outline of the escape groove 274 are parallel to the side wall surface that defines the manifold channel 105 that is the boundary between the adhesion region 161 and the non-adhesion region 162 in the entire region. . In addition, the flow line R passing through the positions (minute regions) of the sections a and c is also substantially parallel to the side wall surface that defines the manifold channel 105. That is, the sections a and c and the flow line R are substantially parallel to each other, and the sections a and c are parallel to the tangential direction at the position (micro area) corresponding to the sections a and c of the flow line R. It consists only of parallel parts.

  On the other hand, the sections b and d are composed of only non-parallel portions that are non-parallel to the tangential direction at positions corresponding to the sections b and d of the flow line R. The downstream end of the section b is connected to the upstream end of the section c so as to form an obtuse angle θ5. One end of the section d is connected to the downstream end of the section c so as to form an obtuse angle θ6.

  As described above, the relief groove 274 has an effect that the adhesive flowing from the left to the right in FIG. 9 when the adhesive is applied to the supply plate flows into the flow path from the outlet opening 151 and the plurality of ink supply ports 115a. It has the function to suppress automatically. However, the air present in the ink becomes bubbles and gradually accumulates in the escape groove 274 over time. As a result, there is a high possibility that ink ejection is hindered. In order to solve this problem, the printer 101 needs to periodically perform a purge operation that drives a pump (not shown) connected to the head 1 to forcibly discharge the air in the head 1 together with the ink. . In this modification, since the escape groove 274 has the shape described in detail with reference to FIG. 10, the air fluidity in the escape groove 274 is increased. This is because air easily moves along the flow line R in the parallel portion, and the corner portion formed by connecting the parallel portion and the non-parallel portion has an obtuse angle, so that air is accumulated in the corner portion. Because it is difficult. Therefore, the air accumulated in the escape groove 274 can be efficiently discharged to the outside through the individual ink flow path 132 from the manifold flow path 105 and the plurality of sub manifold flow paths 105a at the time of purging. Therefore, it is not necessary to make the purge time longer than usual or increase the purge pressure, and the amount of ink discarded during the purge can be minimized.

  In the present embodiment, only one escape groove 274 having an outline parallel to the side wall surface defining the manifold channel 105 is formed, and the width thereof is ½ of the maximum width W of the manifold channel 105. As described above, the air in the escape groove 274 is more easily discharged.

  In this modification, the entire area d of the outline is the downstream end of the ink flow. However, in order to reduce the amount of air accumulated along the area d, for example, the downstream end shown in FIG. It is more preferable to provide an acute angle portion in the area d that protrudes in the downstream direction along the flow line as in X2.

  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 to the above-described embodiments as long as they are described in the claims. Is possible. For example, in the embodiment described above, the example in which the adhesive application direction is parallel to the longitudinal direction of the flow path unit 9 is shown, but the present invention is not limited to this. For example, when the application direction of the adhesive is parallel to the width direction of the flow path unit 9, in FIG. 6, a relief groove including the outlet opening 151 is provided upstream of the outlet opening 151 or two reliefs are provided. The groove 174a may be connected upstream of the outlet opening 151 in the application direction.

  Further, in the example described with reference to FIGS. 6 and 9, the outline of the relief groove is composed of a parallel part and a non-parallel part, but the outline of the one or more grooves may be composed only of the parallel part. Good. Thereby, the air flow in the groove becomes smoother. As described above, the “parallel portion” is not intended to be only 0 ° with respect to the tangential direction of the flow line, but has an angle that does not greatly hinder the movement of air in the groove. Includes what is being done.

  Although an example in which the first flow path is a common ink flow path and the second flow path is an individual ink flow path has been described, the present invention is not limited to this, and can be applied to other portions. is there.

  In the embodiment described above, of the two escape groove groups 174, only the one on the left side in FIG. 6 upstream of the outlet opening 151 and the plurality of ink supply ports 115a in the adhesive application direction is formed. Good. In the escape groove group 174, only the escape groove 174a may be formed. This is because the formation range of the escape groove 174a in the sub-scanning direction includes the formation range of the outlet opening 151 and the plurality of ink supply ports 115a in the sub-scanning direction, and the outline of the escape groove 174a is the escape line of the flow line R. There are parallel parts (main areas 176 and 177) parallel to the tangential direction at positions (micro areas) corresponding to the grooves 174a, and non-parallel parts (areas 178 and 179) are parallel parts (main areas 176 and 177), respectively. ) And obtuse angles θ1 and θ2.

  Further, the shape of the relief groove is (1) that the formation range of the relief groove includes the formation range of the outlet opening (first port) in any one direction within the plate surface, and (2) the shape of the escape groove. The outline has a parallel part parallel to the tangential direction at a position corresponding to the escape groove of the flow line R, and (3) when the outline of the escape groove has a non-parallel part, the non-parallel part As long as the condition that is connected to form an obtuse angle with the parallel portion is satisfied, any change may be made. The reason that “any one direction” is used in (1) is because the application direction of the adhesive may be changed to a direction orthogonal to the one direction satisfying (1) in the head manufacturing process.

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Head main body 2a Discharge surface 9 Flow path unit 21 Actuator unit 101 Inkjet printer 105 Manifold flow path 105a Sub-manifold flow path 108 Discharge port 110 Pressure chamber 114 Communication hole 115 Ink supply hole 115a Ink supply port 122-130 Plate 132 Individual ink flow path 151 Outlet opening 161 Adhesive area 162 Non-adhesive area 170 Escape groove 171 Inner enclosure groove 172 Outer enclosure groove 173 Lattice groove 174 Escape groove group 174a, 174b, 174c, 174d Escape groove 176, 177 Main area of outline 178, 179, 180, 181 Outline area

Claims (12)

A plurality of plates in which through holes are formed are stacked via an adhesive, whereby a first flow path to which liquid is supplied via the first port and a first plate formed on the same plate as the first port. A liquid discharge head having a flow path unit in which a second flow path connected to the first flow path via two ports is formed,
One or a plurality of grooves are formed on the wall surface facing the first flow path of the plate in which the first port and the second port are formed,
With respect to one direction in the plate surface, the formation range of the one or more grooves includes the formation range of the first mouth,
An outline of at least one of the one or more grooves is a tangent at a position corresponding to the outline of the flow line of liquid from the first port to the second port in the first flow path. Has a parallel part parallel to the direction,
When there is a non-parallel portion that is not parallel to the tangential direction at a position corresponding to the outer shape line of the flow line in the outer shape line of the one or more grooves, the non-parallel portion is connected to the parallel portion, and A liquid discharge head, wherein an upstream area of the non-parallel portion with respect to the connection portion and an downstream area of the parallel portion with respect to the connection portion are connected to form an obtuse angle.   The first flow path as a common liquid flow path is connected to a plurality of the second flow paths, which are individual liquid flow paths having a liquid discharge port provided at the tip. The liquid discharge head described.   At least one of the one or more grooves is formed so as to include the plurality of second ports in the one direction further upstream than the most upstream of the plurality of second ports. The liquid discharge head according to claim 2, wherein:   The one direction is orthogonal to a longitudinal direction of the flow path unit, and a region where the plurality of second ports are provided in the first flow path extends in the longitudinal direction. Item 4. The liquid discharge head according to Item 2 or 3. The plurality of second ports are at positions shifted from the first port with respect to the one direction, and a part of the plurality of second ports overlaps with the first port with respect to an orthogonal direction orthogonal to the one direction. And
The liquid ejection head according to claim 2, wherein the one or more grooves extend so as to have both the one-direction component and the orthogonal direction component.   The liquid ejection head according to claim 1, wherein the non-parallel portion is connected to the parallel portion at a downstream end thereof.   The said wall surface of the said plate in which the said 1 or several groove | channel was formed has faced the same direction as the surface in which the said discharge outlet was formed, The any one of Claims 1-6 characterized by the above-mentioned. Liquid discharge head.   8. The liquid ejection head according to claim 1, wherein a plurality of the grooves having an outer shape parallel to a side wall surface defining the first flow path are formed. 9.   Only one groove having an outline parallel to the side wall surface defining the first flow path is formed, and the width thereof is ½ or more of the maximum width of the first flow path. The liquid discharge head according to claim 1.   10. The liquid ejection head according to claim 1, wherein an outline of the one or more grooves is formed of only the parallel portion.   The liquid ejection head according to claim 1, wherein the one or more grooves are provided on both sides of the first port with respect to the one direction.   The liquid discharge head according to claim 1, wherein at least one of an upstream end and a downstream end of each groove forms an acute angle.

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