Liquid ejection head

Abstract

To provide a liquid discharge head which enables downsizing and simplification of a cooling structure of heating parts.SOLUTION: A liquid discharge head according to an embodiment includes: a liquid discharge part; multiple heating parts; and a cooling passage part. The liquid discharge part has multiple nozzle arrays. The heating parts respectively correspond to the multiple nozzle arrays. The cooling passage part has a fewer number of passage parts, in which a coolant flows and which respectively contact with the heating parts, than a number of the nozzle arrays.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] An embodiment of the present invention relates to a liquid ejection head. [Background technology]

[0002] Depending on the component configuration, liquid ejection heads may require the driver ICs to face outward. When such liquid ejection heads have a multiple nozzle row structure, water-cooling circulation paths are provided on the backside of the opposing driver ICs, and heat transfer plates are attached from the outside to dissipate heat.

[0003] However, with the recent demand for high-productivity, high-speed printing, the amount of heat generated by the driver IC tends to increase when it is in operation. This raises concerns that conventional heat dissipation structures may not be able to provide adequate cooling. Improving the cooling effect increases the volume of the cooling structure, which could increase the size of the liquid ejection head and complicate the cooling structure, resulting in increased costs. Because these factors impose a burden on the printer device, there is a need to simplify the structure as much as possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-20451 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem to be solved by the present invention is to provide a liquid ejection head that allows for a compact and simple cooling structure for a heat generating portion. [Means for solving the problem]

[0006] The liquid ejection head of the embodiment includes a liquid ejection unit, a plurality of heat generating units, and a cooling flow path unit. The liquid ejection unit has a plurality of nozzle rows. The heat generating units correspond to the plurality of nozzle rows. The cooling flow path unit has a plurality of flow paths, the number of which is less than the number of nozzle rows, through which cooling water flows and which respectively abut against the plurality of heat generating units. The nozzle rows each extend in a first direction and are arranged in a second direction perpendicular to the first direction. The heat generating unit is a driver IC connected to the liquid ejection unit, and is arranged in a plurality in the second direction. The flow path portions are arranged in a line in the second direction, facing one side or the other side of the driver IC in the second direction, and extending along the first direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing a configuration of a liquid ejection head according to an embodiment. [Figure 2] FIG. 1 is an exploded perspective view showing the configuration of a liquid ejection head according to an embodiment. [Figure 3] FIG. 2 is a side view showing the configuration of a liquid ejection head according to the embodiment. [Figure 4] FIG. 1 is a cross-sectional view showing the configuration of a liquid ejection head according to an embodiment. [Figure 5] FIG. 2 is a diagram showing the configuration of a liquid ejection head according to an embodiment, viewed from the nozzle plate side. [Figure 6] FIG. 2 is a perspective view showing, in partial cross section, the configuration of a head main body and a manifold unit of the liquid ejection head according to the embodiment. [Figure 7] FIG. 2 is a cross-sectional view showing the configuration of a head main body and a manifold unit according to the embodiment. [Figure 8] FIG. 2 is a cross-sectional view showing the configuration of a head main body and a manifold unit according to the embodiment. [Figure 9] FIG. 2 is a diagram illustrating the configuration of a head main body according to the embodiment, with some parts omitted. [Figure 10] FIG. 2 is an exploded perspective view showing the configuration of a cooling channel unit according to the embodiment. [Figure 11] 6A and 6B are explanatory diagrams showing the results of analytical simulations of the liquid ejection head according to the embodiment and the liquid ejection head according to the comparative example. [Figure 12] 6A and 6B are explanatory diagrams showing the results of analytical simulations of the liquid ejection head according to the embodiment and the liquid ejection head according to the comparative example. [Figure 13]FIG. 1 is an explanatory diagram showing the configuration of a liquid ejection device according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A liquid ejection head 1 according to an embodiment and a liquid ejection device 2 using the liquid ejection head 1 will be described below with reference to Figs. 1 to 13. Fig. 1 is a perspective view showing the configuration of the liquid ejection head 1 according to an embodiment, with the cover 15 omitted. Fig. 2 is an exploded perspective view showing the configuration of the liquid ejection head 1, with the cover 15 omitted, Fig. 3 is a side view showing the configuration of the liquid ejection head 1, and Fig. 4 is a cross-sectional view showing the configuration of the liquid ejection head 1, with the cover 15 omitted.

[0009] Fig. 5 is a diagram showing the configuration of the liquid ejection head 1 from the nozzle plate 114 side. Fig. 6 is a perspective view showing, in partial cross section, the configuration of the head main body 11 and manifold unit 12 of the liquid ejection head 1, Fig. 7 is a cross-sectional view showing the configuration of the head main body 11 and manifold unit 12, and Fig. 8 is an enlarged cross-sectional view showing the configuration of the head main body 11 and manifold unit 12.

[0010] Fig. 9 is a diagram showing the configuration of the head main body 11 with some parts omitted. Fig. 10 is an exploded perspective view showing the configuration of the cooling channel unit 13. Figs. 11 and 12 are explanatory diagrams showing the temperature of the driver IC 142 after cooling as a result of analytical simulation of the liquid ejection head 1 according to the embodiment and a liquid ejection head according to a comparative example. Fig. 13 is an explanatory diagram showing the configuration of the liquid ejection device 2 according to the embodiment. In Fig. 2, an example of the flow of cooling water is indicated by dashed arrows.

[0011] 1 to 10 show an X-axis, a Y-axis, and a Z-axis that are orthogonal to each other. In the following description, the direction along the X-axis is referred to as the first direction X, the direction along the Y-axis is referred to as the second direction Y, and the direction along the Z-axis is referred to as the third direction Z. In addition, for the sake of explanation, the configurations in each figure are enlarged, reduced, or omitted as appropriate.

[0012] The liquid ejection head 1 is an inkjet head provided in a liquid ejection device 2 such as the inkjet recording device shown in Fig. 13. The liquid ejection head 1 is provided in a head unit 2130 that includes a supply tank 2132 as a liquid storage section provided in the liquid ejection device 2.

[0013] The liquid ejection head 1 is supplied with ink as a liquid stored in a supply tank 2132. The liquid ejection head 1 may be a non-circulation type head that does not circulate ink, or a circulation type head that circulates ink. In this embodiment, the liquid ejection head 1 will be described using an example of a non-circulation type head. The liquid ejection head 1 is also connected to a cooling device 2116 provided in the liquid ejection device 2, and is supplied with cooling liquid (cooling water) that controls the temperature of the heat generating parts and the ink. The liquid ejection head 1, together with the cooling device 2116, constitutes a water-cooled circulation structure.

[0014] 1 to 4, the liquid ejection head 1 includes a head main body 11, a manifold unit 12, a cooling channel unit 13, a circuit board 14, and a cover 15. For example, the liquid ejection head 1 is a side shooter type four-row integrated structure head that includes two sets of head main bodies 11, each having a pair of actuators 113.

[0015] The head body 11 ejects liquid. As shown in Figures 3 to 9, the head body 11 includes a base plate 111, a frame 112, an actuator 113, a nozzle plate 114, and a mask plate 115. The head body 11 also includes a common liquid chamber 116. In this embodiment, an example will be described in which one head body 11 includes two actuators 113.

[0016] 7 to 9, the base plate 111 is formed in the shape of a rectangular plate from, for example, a ceramic material. The base plate 111 is formed in the shape of a rectangle that is long in one direction (first direction X). As shown in FIG. 9, the base plate 111 has a single supply port 1111 and one or more discharge ports 1112. The base plate 111 is provided with a pair of actuators 113, and a wiring pattern for driving the actuators 113 is formed on it. The supply port 1111 and the discharge port 1112 are through holes that penetrate between both main surfaces of the base plate 111.

[0017] The supply port 1111 is provided singly, for example, at a position facing a first common liquid chamber 1161 (described later) of the common liquid chamber 116. The supply port 1111 is, for example, an elongated hole that is long in one direction along the longitudinal direction (first direction X) of the first common liquid chamber 1161. The supply port 1111 is, for example, a rectangular shape that is long in one direction, or an elongated hole with semicircular ends and a uniform width. The longitudinal width of the supply port 1111 is, for example, set to be equal to or greater than the longitudinal width (length) of the actuator 113, or smaller than the length of the actuator 113, and to a length that is approximately the same as the range (all nozzle range) in which pressure chambers 1131 formed in the actuator 113 that are driven during normal ink ejection are provided.

[0018] For example, two outlets 1112 are provided at positions facing at least one of two third common liquid chambers 1163 (described later) of the common liquid chamber 116. For example, as shown in Fig. 9, the outlet 1112 is provided in the base plate 111 so as to be located adjacent to one end of the pair of actuators 113 in the longitudinal direction and in one of the third common liquid chambers 1163. Note that the common liquid chamber 116 may have a configuration in which two outlets 1112 are provided in each of the two third common liquid chambers 1163.

[0019] 9, the frame 112 is fixed to one main surface of the base plate 111 with an adhesive or the like. The frame 112 surrounds a supply port 1111, a plurality of discharge ports 1112, and an actuator 113, which are provided in the base plate 111.

[0020] For example, the frame 112 is formed in a rectangular frame shape that is long in one direction (first direction X), thereby forming an opening that is long in one direction along the longitudinal direction of the frame 112. In the opening of the frame 112, a pair of actuators 113, a supply port 1111, and two discharge ports 1112 are arranged.

[0021] The actuators 113 are formed in the shape of plates that are long in one direction (first direction X). A pair of actuators 113 are bonded to the mounting surface of the base plate 111. As shown in FIG. 9, the pair of actuators 113 are provided on the base plate 111 in two rows in the short direction (second direction Y) perpendicular to the longitudinal direction of the actuators 113, sandwiching a supply port 1111 therebetween. The actuators 113 are arranged in an opening of the frame 112 and bonded to the main surface of the base plate 111. As a specific example, the actuators 113 are formed by bonding two rectangular plates of piezoelectric material that are long in one direction facing each other so that their polarization directions are opposite to each other. Here, the piezoelectric material is, for example, PZT (lead zirconate titanate). The actuators 113 are bonded to the mounting surface of the base plate 111 with, for example, a thermosetting epoxy adhesive.

[0022] The actuator 113 has, for example, a plurality of pressure chambers 1131 arranged at equal intervals in the longitudinal direction (first direction X). A plurality of grooves are formed in the longitudinal direction of the actuator 113 on the main surface opposite the base plate 111 side of the actuator 113, and these grooves form the pressure chambers 1131. In other words, the actuator 113 has a plurality of walls 1133 arranged at equal intervals in the longitudinal direction and forming grooves therebetween. The plurality of walls 1133 form a plurality of pressure chambers 1131 between adjacent walls. In other words, the plurality of walls 1133 are partition walls that separate the plurality of pressure chambers 1131. Furthermore, the walls 1133 are piezoelectric elements that function as drive elements that change the volume of the pressure chambers 1131 when a drive voltage is applied.

[0023] The surface of the actuator 113 opposite to the base plate 111 is bonded to the nozzle plate 114. In addition, the actuator 113 has a wiring pattern formed thereon for driving the plurality of pressure chambers 1131.

[0024] The pressure chambers 1131 are pressure chambers for ejecting ink from the nozzles 1141 during operations such as printing by the liquid ejection head 1. Note that, in the present embodiment, an example has been described in which the actuator 113 has a plurality of pressure chambers 1131, but, for example, a configuration may be adopted in which the actuator 113 has air chambers that do not eject ink and are arranged alternately with the plurality of pressure chambers 1131.

[0025] As shown in FIGS. 4, 5, 7, and 8, the nozzle plate 114 is formed in a plate shape. The nozzle plate 114 is fixed by adhesive or the like to the main surface of the frame 112 opposite the base plate 111. The nozzle plate 114 has a plurality of nozzles 1141 formed at positions facing the plurality of pressure chambers 1131. In this embodiment, the nozzle plate 114 has two nozzle rows 1142 in which the plurality of nozzles 1141 are aligned in one direction (first direction X). In this embodiment, the liquid ejection head 1 has two sets of head main bodies 11, and therefore, as shown in FIG. 5, the liquid ejection head 1 has four nozzle rows 1142.

[0026] The plurality of nozzles 1141 facing the plurality of pressure chambers 1131 are holes that eject ink when the liquid ejection head 1 performs an operation such as printing.

[0027] The mask plate 115 covers, for example, the main surface on the outer surface side of the nozzle plate 114, the outer periphery of the nozzle plate 114, the outer periphery surface of the frame body 112, and the outer periphery surface of the base plate 111. In addition, the mask plate 115 covers a first manifold 1214 of the manifold unit 12, which will be described later.

[0028] As shown in FIG. 5, the mask plate 115 has a pair of windows 1151 that expose nozzle rows 1142 each consisting of a plurality of nozzles 1141 that eject liquid from a pair of nozzle plates 114 .

[0029] 9, the common liquid chamber 116 communicates with a supply port 1111. The common liquid chamber 116 is provided around the pair of actuators 113. Specifically, the common liquid chamber 116 communicates with the primary side and secondary side of the multiple pressure chambers 1131 of each actuator 113. The common liquid chamber 116 also communicates with a discharge port 1112.

[0030] 9, the common liquid chamber 116 has a first common liquid chamber 1161 that is long in one direction (first direction X), two second common liquid chambers 1162 that are long in one direction (first direction X), and a third common liquid chamber 1163 that connects both ends of the first common liquid chamber 1161 to both ends of the two second common liquid chambers 1162. Furthermore, the common liquid chamber 116 communicates the supply port 1111 with one opening of the multiple pressure chambers 1131 of the actuator 113 via the first common liquid chamber 1161, and communicates the third common liquid chamber 1163 with the other opening of the multiple pressure chambers 1131 via the second common liquid chamber 1162.

[0031] The first common liquid chamber 1161 is formed between a pair of actuators 113. The first common liquid chamber 1161 constitutes an ink flow path from the supply port 1111 to one opening of the plurality of pressure chambers 1131 of each actuator 113. The first common liquid chamber 1161 also constitutes an ink flow path from the supply port 1111 to two third common liquid chambers 1163 on both end sides in the longitudinal direction (first direction X) of the first common liquid chamber 1161 (actuator 113).

[0032] The second common liquid chamber 1162 is formed between each actuator 113 and the frame 112. The second common liquid chamber 1162 forms an ink flow path from the third common liquid chamber 1163 to the other opening of the plurality of pressure chambers 1131.

[0033] The third common liquid chamber 1163 is adjacent to, for example, both ends in the longitudinal direction of the actuator 113. The third common liquid chamber 1163 communicates with the first common liquid chamber 1161 and the two second common liquid chambers 1162 at both ends in the longitudinal direction of the pair of actuators 113. The third common liquid chamber 1163 forms a flow path for part of the ink that reaches the second common liquid chamber 1162 from the first common liquid chamber 1161 without passing through the multiple pressure chambers 1131 of each actuator 113. The third common liquid chamber 1163 also forms a flow path for ink from the first common liquid chamber 1161 and the two second common liquid chambers 1162 to the discharge port 1112.

[0034] 1 to 8, the manifold unit 12 includes a manifold 121, a top plate 122, an ink supply pipe 123, an ink discharge pipe 124, a first cooling water supply pipe 125, a first cooling water discharge pipe 126, a damper 127, and a bypass flow path 128. The numbers of the ink supply pipes 123 and the ink discharge pipes 124 can be set as appropriate. The numbers of the ink supply pipes 123, the ink discharge pipes 124, the first cooling water supply pipes 125, and the first cooling water discharge pipes 126 can be set as appropriate.

[0035] 6 to 8, the manifold 121 includes a supply channel 1211 that is continuous with the supply port 1111 of the base plate 111 and forms a liquid supply channel, a discharge channel 1212 that is continuous with the discharge port 1112 of the base plate 111 and forms a liquid discharge channel, and a first cooling channel 1213 that forms a channel for a cooling fluid. Note that the manifold 121 is connected to a pair of head bodies 11, and therefore includes a pair of supply channels 1211 and a pair of discharge channels 1212.

[0036] One main surface of the manifold 121 is fixed to the main surface of the base plate 111. A top plate 122 is fixed to the main surface of the manifold 121 opposite to the main surface to which the base plate 111 is fixed. The ink supply pipe 123, the ink discharge pipe 124, the first cooling water supply pipe 125, and the first cooling water discharge pipe 126 are fixed to the manifold 121 via the top plate 122, for example.

[0037] The manifold 121 includes, for example, a first manifold 1214 and a second manifold 1215. The manifold 121 is formed by assembling the first manifold 1214 and the second manifold 1215 together.

[0038] The supply channel 1211 is a rectangular liquid chamber that is long in one direction (first direction X) and is formed by holes or grooves in the manifold 121. The supply channel 1211 fluidly connects the ink supply pipe 123 and the supply port 1111 of the base plate 111.

[0039] For example, the supply path 1211 is a rectangular liquid chamber that extends along the longitudinal direction of the actuator 113 and the longitudinal direction of the supply port 1111. The supply path 1211 is a liquid flow path between the ink supply pipe 123 and the supply port 1111. The supply port 1111 is continuous with one side of the supply path 1211, and a damper 127 is provided on the ceiling portion 12111 on the other side of the supply path 1211.

[0040] The discharge channel 1212 is a flow path formed by a hole or a groove in the manifold 121. The discharge channel 1212 fluidly connects the ink discharge tube 124 and the two discharge ports 1112 of the base plate 111, for example.

[0041] The first cooling flow path 1213 is a flow path formed by holes or grooves in the manifold 121. The first cooling flow path 1213 fluidly connects the first cooling water supply pipe 125 and the first cooling water discharge pipe 126. The first cooling flow path 1213 cools the head main body 11, which is the liquid ejection part.

[0042] Both ends of the primary side and secondary side of the first cooling flow path 1213 are openings connected to a first cooling water supply pipe 125 and a first cooling water discharge pipe 126 provided on one main surface of the manifold 121. In addition, the first cooling flow path 1213 is formed to be able to exchange heat with the base plate 111 fixed to the manifold 121.

[0043] The first manifold 1214 is formed in a rectangular plate shape. The first manifold 1214 has grooves and openings formed therein that constitute, for example, a portion of the pair of supply paths 1211, a portion of the pair of discharge paths 1212, and a portion of the first cooling path 1213. The arrangement, size, etc. of the grooves and openings that constitute a portion of the supply paths 1211 and the discharge paths 1212 are set appropriately based on the shapes of the supply paths 1211 and the discharge paths 1212 and the shapes of the other fluid paths.

[0044] The second manifold 1215 is formed in a rectangular plate shape. The second manifold 1215 has grooves and openings formed therein that constitute, for example, a portion of the pair of supply paths 1211, a portion of the pair of discharge paths 1212, and a portion of the first cooling path 1213. The arrangement, size, etc. of the grooves and openings that constitute a portion of the supply paths 1211 and the discharge paths 1212 are set appropriately based on the shapes of the supply paths 1211 and the discharge paths 1212 and the shapes of the other fluid paths.

[0045] The first manifold 1214 and the second manifold 1215 are joined together to form the supply path 1211, the discharge path 1212, and the first cooling path 1213.

[0046] The top plate 122 is provided on the surface of the manifold 121 opposite to the surface on which the base plate 111 is provided. The top plate 122 has openings that connect the ink supply pipe 123, the ink discharge pipe 124, the first cooling water supply pipe 125, and the first cooling water discharge pipe 126 to the supply path 1211, the discharge path 1212, and the first cooling flow path 1213 of the manifold 121. For example, the top plate 122 is formed of two plate-shaped members. One of the ink supply pipe 123 and the ink discharge pipe 124, and one of the first cooling water supply pipe 125 and the first cooling water discharge pipe 126 are provided on one of the plate-shaped members. Furthermore, the other of the ink supply pipe 123 and the ink discharge pipe 124, and the other of the first cooling water supply pipe 125 and the first cooling water discharge pipe 126 are provided on the other plate-shaped member.

[0047] The ink supply pipe 123 is connected to the supply path 1211. The ink discharge pipe 124 is connected to the discharge path 1212. In this embodiment, the liquid ejection head 1 includes a pair of head bodies 11, and therefore a pair of ink supply pipes 123 and a pair of ink discharge pipes 124 are provided. The first cooling water supply pipe 125 and the first cooling water discharge pipe 126 are connected to the primary side and secondary side of the first cooling flow path 1213.

[0048] In this embodiment, a pair of ink supply pipes 123 and a first cooling water discharge pipe 126 are arranged at one end of the manifold 121 in the longitudinal direction, and a pair of ink discharge pipes 124 and a first cooling water supply pipe 125 are arranged at the other end of the manifold 121 in the longitudinal direction.

[0049] 6 to 8, the damper 127 is formed in the shape of an elastically deformable thin film or sheet. As shown in Fig. 7, the damper 127 covers the ceiling portion 12111 of the supply path 1211 formed in the second manifold 1215. The damper 127 elastically deforms in response to pressure fluctuations in the supply path 1211. One surface of the damper 127 faces the supply path 1211.

[0050] As a specific example, damper 127 is formed of a polyimide film. Damper 127 is formed in a rectangular shape that is long in the same direction (first direction X) as the longitudinal direction of the opening of ceiling portion 12111 of supply path 1211 that is long in one direction (first direction X).

[0051] 6, the bypass flow path 128 connects the ceiling portion 12111 of the supply path 1211 to the common liquid chamber 116 or the secondary side of the common liquid chamber 116. The common liquid chamber 116 or the secondary side of the common liquid chamber 116 to which the bypass flow path 128 connects is, for example, the second common liquid chamber 1162 or the third common liquid chamber 1163 of the common liquid chamber 116, the discharge path 1212, or the ink discharge pipe 124. The fluid resistance of the bypass flow path 128 is greater than the fluid resistance of the supply path 1211 and the fluid resistance of the common liquid chamber 116.

[0052] The bypass flow path 128 bypasses the supply path 1211 and the common liquid chamber 116, thereby discharging air bubbles from the supply path 1211 during maintenance or ink filling. The bypass flow path 128 has a cross section that is rectangular or circular. The bypass flow path 128 may be shaped, for example, linear or partially bent.

[0053] 2, 4 and 10, the cooling channel unit 13 includes, for example, a cooling channel portion 131, a cooling water top plate 132, a second cooling water supply pipe 133, and a second cooling water discharge pipe 134. The cooling channel unit 13 is connected to the cooling device 2116 of the liquid discharger 2. The cooling channel unit 13 is a cooling structure that cools the driver IC 142, which is a heat generating element. The cooling flow path section 131 is connected to a second cooling water supply pipe 133 and a second cooling water discharge pipe 134 via a cooling water top plate 132. The cooling flow path section 131 includes a branch flow path 1311 connected to the second cooling water supply pipe 133, a second cooling flow path 1312 that cools a plurality of driver ICs (described later) that are heat-generating parts, and a junction flow path 1313.

[0054] The branch flow path 1311 branches the cooling water supplied from the second cooling water supply pipe 133 into two directions. One of the flow paths branched by the branch flow path 1311 is connected to the first cooling flow path 1213, and the other flow path branched by the branch flow path 1311 is connected to the second cooling flow path 1312.

[0055] The second cooling flow path 1312 is connected to one of the flow paths branched by the branch flow path 1311. The number of the second cooling flow paths 1312 is less than the number of driver ICs on the primary side, and the second cooling flow paths 1312 branch into multiple flow paths, forming a flow path where the multiple flow paths merge into one on the secondary side. The second cooling flow path 1312 cools the driver IC 142.

[0056] As a specific example, in this embodiment, there are four nozzle rows 1142, four actuators 113 (four rows), and four driver ICs 142 (four rows). Therefore, as shown in Figures 2, 4, and 10, the cooling flow path section 131 has three flow path sections 13121 that constitute the second cooling flow path 1312. These three flow path sections 13121 are long in one direction (first direction X) and are arranged side by side in a direction (second direction Y) perpendicular to the longitudinal direction of the flow path section 13121.

[0057] The three flow path sections 13121 are configured by a pair (two) single-row cooling flow path sections 13122 and one multi-row cooling flow path section 13123. The pair of single-row cooling flow path sections 13122 are arranged on both end sides (outside) in the arrangement direction (second direction Y) of the three flow path sections 13121. Each of the pair of single-row cooling flow path sections 13122 cools one driver IC 142 that drives the actuator 113 that ejects ink from the single nozzle row 1142. The corresponding driver IC 142 abuts against the outer surface of the single-row cooling flow path section 13122.

[0058] The multi-row cooling channel section 13123 is disposed on the inside in the arrangement direction (second direction Y) of the three channel sections 13121. That is, the multi-row cooling channel section 13123 is disposed between the pair of single-row cooling channel sections 13122 in the arrangement direction (second direction Y) of the three channel sections 13121. The multi-row cooling channel section 13123 cools two driver ICs 142 that respectively drive two actuators 113 that eject ink from two adjacent nozzle rows 1142 of the two sets of head bodies 11. The two corresponding driver ICs 142 abut on different outer surfaces of the multi-row cooling channel section 13123.

[0059] 4 and 10, the width WA of the flow path 131221 formed by the single-row cooling path section 13122 is narrower than the width WB of the flow path 131231 formed by the multi-row cooling path section 13123. The width WA of the flow path 131221 and the width WB of the flow path 131231 are widths in the second direction Y in FIG. 10. Furthermore, the cross-sectional area of ​​the flow path 131221 formed by the single-row cooling path section 13122 is smaller than the cross-sectional area of ​​the flow path 131221 formed by the multi-row cooling path section 13123. This is because the single-row cooling path section 13122 cools one driver IC 142, while the multi-row cooling path section 13123 cools two driver ICs 142. Therefore, in order to make the cooling capacity of the multi-row cooling flow path section 13123 higher than that of the single-row cooling flow path section 13122, the width WB of the flow path 131231 of the multi-row cooling flow path section 13123 is larger than the width WA of the flow path 131221 of the single-row cooling flow path section 13122.

[0060] The confluence passage 1313 joins the first cooling passage 1213 and the second cooling passage 1312 and connects them to the second cooling water discharge pipe 134 .

[0061] The cooling flow path section 131 includes, for example, a cooling manifold 1314 , a cover 1315 that covers the cooling manifold 1314 , and a pair of cooling blocks 1316 that are provided on the cover 1315 .

[0062] The second cooling flow path 1312 is a flow path formed by holes and grooves formed in a cooling manifold 1314 , a cover 1315 and a pair of cooling blocks 1316 .

[0063] The cooling manifold 1314 is formed in a plate or block shape. The cooling manifold 1314 is fixed to, for example, the manifold 121. Two openings 13141 are formed in the cooling manifold 1314, in which a part of the wiring film 141 on which a driver IC 142 (described later) of the circuit board 14 is mounted and the printed wiring board 143 are disposed. The openings 13141 are aligned along the longitudinal direction of the flow path portion 13121 (first direction X).

[0064] The cooling manifold 1314 has three portions adjacent to the two openings 13141 that each form part of three flow path sections 13121. For example, a groove 13142 is formed in the cooling manifold 1314. The groove 13142 is shaped so that one flow path branches into three flow paths: flow paths 131231 formed by two single-row cooling flow path sections 13122 and a flow path 131231 formed by one multi-row cooling flow path section 13123, and the three flow paths then merge together.

[0065] The cover 1315 is formed in a plate shape. Two openings 13151 are formed in the cover 1315 along the longitudinal direction (first direction X) of the flow path portion 13121, and a part of the wiring film 141 and the printed wiring board 143 are disposed therein. The cover 1315 covers a groove 13142 formed in the cooling manifold 1314, and is fixed to the cooling manifold 1314 in a liquid-tight manner. The cover 1315 and the cooling manifold 1314 form the second cooling flow path 1312. When the cover 1315 is integrally assembled with the cooling manifold 1314, the two openings 13151 of the cover 1315 face the opening 13141 of the cooling manifold 1314. The cover 1315 is formed with a plurality of openings that connect the second cooling flow path 1312 to the branch flow paths 1311 and the merging flow path 1313, for example.

[0066] The cooling block 1316 has grooves and openings formed therein that form the branch flow paths 1311 or the merging flow paths 1313. That is, one of the pair of cooling blocks 1316 forms the branch flow paths 1311, and the other cooling block 1316 forms the merging flow path 1313. The pair of cooling blocks 1316 are fixed to a cover 1315. The pair of cooling blocks 1316 face each other in the first direction X at a distance that allows the wiring film 141 of the circuit board 14 and a printed wiring board 143 (described later) to be disposed therebetween. The cooling block 1316 has, for example, a pipe portion 13161 that connects the branch flow paths 1311 or the merging flow path 1313 to the first cooling water supply pipe 125 or the first cooling water discharge pipe 126. The cooling block 1316 is also formed with a plurality of ribs 13162 and a plurality of grooves 13163 for arranging and supporting printed wiring boards 143 (described later) of the four circuit boards 14, for example.

[0067] The cooling water top plate 132 is provided on the surface opposite to the surface on which the cover 1315 of the pair of cooling blocks 1316 is provided. For example, a pair of cooling water top plates 132 are provided. Each cooling water top plate 132 has an opening that connects the second cooling water supply pipe 133 or the second cooling water discharge pipe 134 to the branch flow path 1311 or the junction flow path 1313 of the cooling block 1316. The cooling water top plate 132 has a plurality of grooves formed therein that, for example, place and support a printed wiring board 143.

[0068] 1 to 4, one end of circuit board 14 is connected to the wiring pattern of actuator 113 via the wiring pattern of base plate 111. Circuit board 14 includes, for example, wiring film 141, driver IC 142 mounted on the wiring film, and printed wiring board 143 mounted on the wiring film.

[0069] The circuit board 14 drives the actuator 113 by applying a drive voltage to the actuator 113 via the wiring pattern of the base plate 111 using the driver IC 142 , thereby increasing or decreasing the volume of the pressure chamber 1131 and causing droplets to be ejected from the nozzle 1141 .

[0070] The wiring film 141 is a film substrate formed in a film shape and on which a wiring pattern is formed. For example, a plurality of wiring films 141 are provided. The wiring film 141 is, for example, a COF (Chip on Film) on which a driver IC 142 is mounted. For example, the number of wiring films 141 is the same as the number of actuators 113 provided in one head main body 11, that is, the same number as the number of nozzle rows 1142. One wiring film 141 is connected to one actuator 113. Note that a configuration may be adopted in which a plurality of wiring films 141 are connected to one actuator 113. In this case, the number of wiring film rows and driver IC rows formed by the plurality of wiring films 141 and the driver ICs 142 mounted on the wiring films 141 is the same as the number of actuators 113.

[0071] In this embodiment, the head main body 11 is configured to have two nozzle rows 1142 (two actuators 113), and therefore two wiring films 141 are provided on one head main body 11. A liquid ejection head 1 having two sets of head main bodies 11 has four wiring films 141. The four wiring films 141 are arranged, for example, to extend in the third direction Z, and in this position, are arranged side by side in the second direction Y.

[0072] The driver IC 142 is electrically connected to the wiring pattern formed in the pressure chamber 1131 via the wiring film 141. The driver IC 142 is a heat-generating part that generates heat. The driver IC 142 is mounted on the outer surface side of the wiring film 141. Here, the outer surface side of the wiring film 141 refers to the surface opposite to the surface (inner surface) on which the two wiring films 141 of one head main body 11 face each other when the wiring film 141 is disposed so as to extend in the third direction Z. In other words, the outer surface of the wiring film 141 refers to the outer side in the second direction Y of the head main body 11 when the center side of the head main body 11 in the second direction Y is defined as the inner side. Therefore, the outer surfaces of the inner two wiring films 141 of the four wiring films 141 of the two sets of head main bodies 11 face each other.

[0073] The surface of the driver IC 142 opposite to the mounting surface mounted on the wiring film 141 abuts against the outer surface of the flow path portion 13121. For example, the surface of the driver IC 142 directly contacts the outer surface of the flow path portion 13121. One driver IC 142 is provided for one wiring film 141. Note that a plurality of driver ICs 142 may be provided to drive one actuator 113, and these multiple driver ICs 142 may be provided on one wiring film 141 to form a driver IC row. In this case, multiple driver ICs 142 in the same driver IC row abut against the corresponding flow path portion 13121.

[0074] One printed wiring board 143 is, for example, a PWA (Printing Wiring Assembly) on which various electronic components and connectors are mounted.

[0075] The cover 15 covers or houses a part of the head body 11 , a part of the manifold unit 12 and the circuit board 14 .

[0076] The liquid ejection head 1 configured in this manner has a first cooling flow path 1213 that cools the head main body 11, which is a liquid ejection section, and a second cooling flow path 1312 that cools the driver IC 142, which is a heat-generating section, by the manifold unit 12 and the cooling flow path unit 13. Cooling water supplied from the second cooling water supply pipe 133 passes through the first cooling flow path 1213 and the second cooling flow path 1312, and is discharged from the second cooling water discharge pipe 134. The cooling water flowing through the first cooling flow path 1213 cools the head main body 11, and the cooling water flowing through the second cooling flow path 1312 cools the driver IC 142.

[0077] The second cooling flow path 1312 has a plurality of flow path sections 13121 (three rows), which is fewer than the plurality of nozzle rows 1142 (four rows) and the plurality of actuators 113 (four rows). Of the plurality of flow path sections 13121, the flow path sections 13121 located on both ends (outsides) in the arrangement direction (second direction Y) constitute single-row cooling flow path sections 13122 that cool the driver ICs 142 corresponding to the single nozzle row 1142 (one actuator 113). Of the plurality of flow path sections 13121, the flow path section 13121 between a pair of single-row cooling flow path sections 13122 constitutes a multi-row cooling flow path section 13123 that cools, for example, two driver ICs 142 corresponding to the two nozzle rows 1142 (two actuators 113). Therefore, the number of flow path sections 13121 in the second cooling flow path 1312 may be fewer than the number of nozzle rows 1142 (actuators 113). Therefore, the liquid ejection head 1 can be prevented from becoming large.

[0078] Furthermore, the width WB and cross-sectional area of ​​the flow paths 131231 formed in the multi-row cooling flow path section 13123 are larger than the width WA and cross-sectional area of ​​the flow paths 131221 formed in the single-row cooling flow path section 13122. As a result, the multi-row cooling flow path section 13123 has a high cooling function even when cooling two driver ICs 142.

[0079] The second cooling flow path 1312 may have a simple configuration in which the driver IC is in contact with the outer surfaces of multiple flow path sections 13121 through which cooling water passes. The second cooling flow path 1312 may have a simple configuration in which a cooling manifold 1314, a cover 1315, and a pair of cooling blocks 1316 are integrally assembled.

[0080] The liquid ejection head 1 can cool the driver IC 142, which is a heat generating element, by the second cooling flow path 1312, thereby making it possible to suppress damage caused by heat to components around the driver IC 142. Furthermore, the liquid ejection head 1 can cool the head main body 11 by the first cooling flow path 1213, making it possible to suppress deterioration of printing accuracy due to heat.

[0081] 11 and 12 show the cooling effect obtained by analytical simulation when the driver IC 142 is cooled in the liquid ejection head 1 of the embodiment and the liquid ejection head of the comparative example. Note that Fig. 11 shows the temperature after cooling of the outer driver IC 142 cooled by the single-row cooling channel section 13122. Fig. 12 shows the temperature after cooling of the inner driver IC 142 cooled by the multi-row cooling channel section 13123.

[0082] Here, the water-cooling circulation structure used in the liquid ejection head of the comparative example is configured so that cooling channels are provided on the backside of each of two rows of driver ICs out of four rows of outward-facing driver ICs, i.e., on the inside of each of the two rows, and a metal heat transfer plate is attached to the surface of the driver ICs and fixed to the channel parts that form the cooling channels. The cooling channels are configured to have two channel sections. There is one cooling water supply line, which branches in two directions to form two channel sections and merges on the discharge line.

[0083] 11 and 12, it was found that the liquid ejection head 1 of the embodiment can lower the temperature of the driver IC 142 by approximately -20°C more than the liquid ejection head of the comparative example, for both the outer driver IC 142 and the inner driver IC 142. This demonstrates that the liquid ejection head 1 of the embodiment can achieve a high cooling effect.

[0084] 13, a liquid ejection device 2 having a liquid ejection head 1 will be described. The liquid ejection device 2 includes a housing 2111, a medium supply unit 2112, an image forming unit 2113, a medium ejection unit 2114, a conveying device 2115 which is a support device, a cooling device 2116, a maintenance device 2117, and a control unit 2118.

[0085] The liquid ejection device 2 is an inkjet printer that performs an image formation process on paper P by ejecting liquid such as ink while transporting the paper P as a recording medium, which is the object of ejection, along a predetermined transport path 2001 that runs from a medium supply section 2112 through an image forming section 2113 to a medium ejection section 2114.

[0086] The medium supply unit 2112 includes a plurality of paper feed cassettes 21121. The image forming unit 2113 includes a support unit 2120 that supports paper, and a plurality of head units 2130 that are arranged above and facing the support unit 2120. The medium discharge unit 2114 includes a paper discharge tray 21141.

[0087] The support section 2120 includes a conveyor belt 21201 that is looped in a predetermined area where image formation is performed, a support plate 21202 that supports the conveyor belt 21201 from the back side, and a plurality of belt rollers 21203 that are provided on the back side of the conveyor belt 21201.

[0088] The head unit 2130 includes liquid ejection heads 1 which are multiple inkjet heads, multiple supply tanks 2132 as liquid tanks mounted on each liquid ejection head 1, a pump 2134 which supplies ink, and a connection flow path 2135 which connects the liquid ejection heads 1 and the supply tanks 2132.

[0089] In this embodiment, the liquid ejection heads 1 are provided with four colors of liquid ejection heads 1 (cyan, magenta, yellow, and black), and four color supply tanks 2132 that respectively store ink of each color. The supply tanks 2132 are connected to the liquid ejection heads 1 by connection flow paths 2135.

[0090] The pump 2134 is a liquid-transfer pump that is configured, for example, as a piezoelectric pump. The pump 2134 is connected to the control unit 2118, and is controlled by the control unit 2118.

[0091] The connection flow path 2135 includes a supply flow path connected to the ink supply pipe 123 of the liquid ejection head 1. The connection flow path 2135 also includes a recovery flow path connected to the ink discharge pipe 124 of the liquid ejection head 1. For example, since the liquid ejection head 1 is of a non-circulation type, the recovery circuit is connected to a maintenance device 2117. Note that, for example, if the liquid ejection head 1 is of a circulation type, the recovery flow path is connected to a supply tank 2132.

[0092] The transport device 2115 transports the paper P along a transport path 2001 that runs from a paper feed cassette 21121 in the medium supply unit 2112, through the image forming unit 2113, to a paper discharge tray 21141 in the medium discharge unit 2114. The transport device 2115 includes a plurality of guide plate pairs 21211-21218 and a plurality of transport rollers 21221-21228 that are arranged along the transport path 2001. The transport device 2115 supports the paper P so that it can move relative to the liquid ejection head 1.

[0093] The cooling device 2116 includes a cooling water tank 21161, a cooling circuit 21162 such as piping or tubes for supplying cooling water, a pump for supplying cooling water, and a cooler for adjusting the temperature of the cooling water. The cooling device 2116 supplies cooling water from the cooling water tank 21161, which has been adjusted to a predetermined temperature by the cooler, to the second cooling water supply pipe 133 via the cooling circuit 21162 by the pump. The cooling device 2116 also recovers water that has passed through the first cooling flow path 1213 and the second cooling flow path 1312 and been discharged from the second cooling water discharge pipe 134, into the cooling water tank 21161 via the cooling circuit 21162. The cooler is, for example, a cooler.

[0094] The maintenance device 2117, for example, during maintenance, sucks and recovers ink remaining on the outer surface of the nozzle plate 114. Furthermore, if the liquid ejection head 1 is of a non-circulation type, the maintenance device 2117 recovers ink from inside the head body 11 through the nozzles 1141 during maintenance. Such a maintenance device 2117 has a tray, tank, or the like for storing the recovered ink.

[0095] The control unit 2118 includes a CPU 21181 as an example of a processor, a ROM (Read Only Memory) for storing various programs, a RAM (Random Access Memory) for temporarily storing various variable data and image data, and other memories, and an interface unit for inputting data from the outside and outputting data to the outside.

[0096] In the liquid ejection head 1 and liquid ejection device 2 according to the above-described embodiments, the number of flow path sections 13121 that cool the driver ICs 142, which are heat-generating sections, is fewer than the number of nozzle rows 1142 and the number of actuators 113. In addition, the driver ICs 142 abut on the outer surfaces of the flow path sections 13121. Therefore, the liquid ejection head 1 and the liquid ejection device 2 can be made smaller and simpler while ensuring the high cooling function of the second cooling flow path 1312 of the cooling flow path unit 13, which is the cooling structure.

[0097] It should be noted that the embodiments of the present invention are not limited to the above-described configuration. For example, in the above example, the head main body 11 is of a non-circulating type, but it may be of a circulating type.

[0098] Furthermore, in the above example, the liquid ejection head 1 has been described as having a configuration with four nozzle rows, but this is not limiting. For example, the liquid ejection head 1 may have three head bodies 11 and a configuration with six nozzle rows. In order to achieve such a liquid ejection head 1, a pair of single-row cooling channel sections 13122 may be provided on both ends in the arrangement direction of the nozzle rows (second direction Y), and two (a pair of) multi-row cooling channel sections 13123 may be provided between the pair of single-row cooling channel sections 13122.

[0099] In the above example, the surface of the driver IC 142 is in direct contact with the outer surface of the flow path portion 13121. However, the present invention is not limited to this. For example, the driver IC 142 may be configured to be in contact with the outer surface of the flow path portion 13121 via a sheet-like, tape-like, gel-like, or liquid-like member made of a material with high thermal conductivity.

[0100] In the above embodiment, the liquid ejection head 1 and the liquid ejection device 2 are used in a recording device that ejects ink as a liquid, but the present invention is not limited to this. That is, the liquid ejection head 1 and the liquid ejection device 2 can also be used in, for example, 3D printers, industrial manufacturing machines, and medical applications.

[0101] According to at least one of the embodiments described above, by providing a plurality of flow path sections that contact the driver ICs, which number is less than the number of nozzle rows, it is possible to reduce the size and simplify the cooling structure while ensuring high cooling performance.

[0102] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. The following is a description equivalent to the invention described in the original claims of the present application. [1] A liquid ejection unit having a plurality of nozzle rows; a plurality of heat generating units corresponding to the plurality of nozzle rows; a cooling flow path portion having a plurality of flow path portions, the number of which is less than the number of the nozzle rows, through which cooling water flows and which come into contact with the plurality of heat generating portions, respectively; A liquid ejection head comprising: [2] The plurality of nozzle rows each extend in a first direction and are arranged side by side in a second direction perpendicular to the first direction; the heat generating unit is a driver IC connected to the liquid ejection unit, and a plurality of the heat generating units are arranged in the second direction; The liquid ejection head described in [1], wherein the flow path portions are arranged in a row in the second direction, are arranged opposite one or the other side of the driver IC in the second direction, and extend along the first direction. [3] The plurality of flow path sections include a pair of single-row cooling flow path sections arranged at both ends in the arrangement direction, and a multi-row cooling flow path section arranged between the pair of single-row cooling flow path sections, A liquid ejection head as described in [2], wherein the heat generating portions of the multi-row cooling flow path portion are arranged opposite each other on both sides of the second direction, and the width of the flow path in the second direction is larger than the width of the flow path in the second direction of the single-row cooling flow path portion. [4] The liquid ejection head according to [2] or [3], wherein the cooling flow path section has a branch flow path that branches into a flow path that cools the liquid ejection section. [5] The nozzle rows are four rows, A liquid ejection head described in any one of [2] to [4], wherein the cooling flow path section has three of the flow path sections, and has two openings in which the multiple heating elements are arranged between the three flow path sections adjacent to each other in the second direction. [Explanation of symbols]

[0103] 1...liquid ejection head, 2...liquid ejection device, 11...head body, 12...manifold unit, 13...cooling channel unit, 14...circuit board, 15...cover, 111...base plate, 112...frame body, 113...actuator, 114...nozzle plate, 115...mask plate, 116...common liquid chamber, 121...manifold, 122...top plate, 123...ink supply pipe, 124...ink discharge pipe, 125...first cooling water supply pipe, 126...first cooling water discharge pipe, 127...damper, 128...bypass channel, 131...cooling channel section, 13 2...cooling water top plate, 133...second cooling water supply pipe, 134...second cooling water discharge pipe, 141...wiring film, 142...driver IC, 143...printed wiring board, 1111...supply port, 1112...discharge port, 1131...pressure chamber, 1133...wall, 1141...nozzle, 1142...nozzle row, 1151...window, 1161...first common liquid chamber, 1162...second common liquid chamber, 1163...third common liquid chamber, 1211...supply channel, 1212...discharge channel, 1213...first cooling flow channel, 1214...first manifold, 1215...second manifold, 1311...branch flow 1312...second cooling flow path, 1313...merging flow path, 1314...cooling manifold, 1315...cover, 1316...cooling block, 2001...transport path, 2111...casing, 2112...medium supply unit, 2113...image forming unit, 2114...medium discharge unit, 2115...transport device, 2116...cooling device, 2117...maintenance device, 2118...control unit, 2120...support unit, 2130...head unit, 2132...supply tank, 2134...pump, 2135...connecting flow path, 12111...ceiling unit, 13121...flow path unit, 13122...single Row cooling flow path section, 13123...multiple row cooling flow path section, 13141...opening, 13142...groove, 13151...opening, 13161...pipe section, 13162...rib, 13163...groove, 21121...paper feed cassette, 21141...output tray, 21161...cooling water tank, 21162...cooling circuit, 21181...CPU, 21201...conveyor belt, 21202...support plate, 21203...belt roller, 21211-21218...guide plate pair, 21221-21228...conveyor roller, 131221...flow path, 131231...flow path.

Claims

1. a liquid ejection unit having a plurality of nozzle rows; a plurality of heat generating units corresponding to the plurality of nozzle rows; a cooling flow path portion having a plurality of flow path portions, the number of which is less than the number of the nozzle rows, through which cooling water flows and which come into contact with the plurality of heat generating portions, respectively; Equipped with The plurality of nozzle rows each extend in a first direction and are arranged side by side in a second direction perpendicular to the first direction, the heat generating unit is a driver IC connected to the liquid ejection unit, and a plurality of the heat generating units are arranged in the second direction; The liquid ejection head includes a plurality of flow path portions arranged side by side in the second direction, arranged to face one side or the other side of the driver IC in the second direction, and extending along the first direction.

2. the plurality of flow path sections include a pair of single-row cooling flow path sections arranged at both ends in the arrangement direction, and a multi-row cooling flow path section arranged between the pair of single-row cooling flow path sections, 2. A liquid ejection head as described in claim 1, wherein the heat generating portions of the multi-row cooling flow path section are arranged opposite each other on both sides of the second direction, and the width of the flow path in the second direction is larger than the width of the flow path in the second direction of the single-row cooling flow path section.

3. 3. The liquid ejection head according to claim 1, wherein the cooling flow path section has a branch flow path that branches into a flow path that cools the liquid ejection section.

4. The nozzle rows are four rows, A liquid ejection head described in any one of claims 1 to 3, wherein the cooling flow path portion has three of the flow path portions, and has two openings between the three flow path portions adjacent to each other in the second direction, in which the multiple heat generating portions are arranged.

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