Liquid discharge head

Abstract

This liquid discharge head comprises a first IC, second ICs, and wiring. On the basis of a communication signal from the first IC, the plurality of second ICs drive discharge parts that discharge a liquid. The wiring communicably connects the first IC and the plurality of second ICs. The wiring includes a first communication path and a second communication path that branch from a first branch part connected to the first IC. The first communication path and the second communication path are each connected to the second ICs by fly-by wiring in which the communication path branches at a second branch part.

Description

Liquid ejection head

[0001] The present disclosure relates to a liquid ejection head.

[0002] Conventionally, liquid ejection heads that eject liquid toward a recording medium are known. In addition, various techniques for improving the quality of transmitted signals in wiring boards mounted on devices such as liquid ejection heads have been proposed (see, for example, Patent Document 1).

[0003] Japanese Unexamined Patent Publication No. 2014-212215

[0004] A liquid ejection head according to one aspect of the present disclosure includes a first IC, a second IC, and a wiring. The plurality of second ICs drive ejection units that eject liquid based on a communication signal from the first IC. The wiring communicatively connects the first IC and the plurality of second ICs. The wiring includes a first communication path and a second communication path that branch from a first branch portion connected to the first IC. Each of the first communication path and the second communication path is connected to the second IC by a fly-by wiring in which the communication path branches at a second branch portion.

[0005] FIG. 1 is a side view schematically showing a printer according to an embodiment. FIG. 2 is a plan view schematically showing the printer according to the embodiment. FIG. 3 is a block diagram showing a configuration example of a liquid ejection head. FIG. 4 is a plan view schematically showing the liquid ejection head. FIG. 5 is a side view schematically showing the liquid ejection head. FIG. 6 is a diagram for explaining wiring according to the embodiment. FIG. 7 is a side view showing a mounting example of substrates of a control IC and a drive IC. FIG. 8 is a plan view of a substrate on which the control IC is mounted. FIG. 9 is a diagram showing another example of divided regions in a region. FIG. 10 is a diagram for explaining wiring according to a modification. FIG. 11 is a diagram for explaining wiring according to a conventional technique.

[0006] The embodiments for implementing the liquid discharge head according to this disclosure (hereinafter referred to as "Embodiments") will be described in detail below with reference to the drawings. However, this disclosure is not limited by these embodiments. Furthermore, each embodiment can be combined as appropriate, provided that the processing content is not inconsistent. Also, the same parts are denoted by the same reference numerals in each of the following embodiments, and redundant descriptions are omitted.

[0007] Conventionally, liquid dispensing heads that dispense liquid onto recording media are known. Furthermore, various technologies have been proposed to improve the quality of transmitted signals on wiring boards mounted on devices such as liquid dispensing heads (see, for example, Patent Document 1 above).

[0008] Incidentally, the liquid dispensing head includes, for example, a first IC and a plurality of second ICs, each of which is configured to drive the dispensing section of the liquid dispensing head based on a communication signal from the first IC.

[0009] However, in the conventional technology, in a configuration in which a communication signal is transmitted from a first IC to multiple second ICs, the quality of the communication signal was not improved. In other words, there was room for improvement in the conventional technology in terms of improving the quality of the communication signal.

[0010] Therefore, there is a need to realize a liquid dispensing head that can solve the above problems and improve the quality of communication signals.

[0011] <About the Printer Configuration> First, an overview of the printer 100, including the liquid ejection head 1 according to the embodiment, will be described with reference to Figures 1 and 2. Figure 1 is a schematic side view showing the printer 100 according to the embodiment. Figure 2 is a schematic top view showing the printer 100 according to the embodiment. The printer 100 according to the embodiment is, for example, a color inkjet printer. Note that the printer 100 is an example of a recording device. For the sake of clarity, Figure 1 shows a three-dimensional Cartesian coordinate system including the X-axis, where the right direction of the paper is the positive direction, and the Y-axis, where the back direction of the paper is the positive direction. Such a Cartesian coordinate system is also shown in other drawings used in the following explanation.

[0012] Furthermore, in the following explanation, for convenience, the positive Z-axis direction may be referred to as "up." The X-axis direction is the direction in which the printing paper P is transported. Also, a plan view refers to looking from the positive Z-axis side towards the negative Z-axis direction.

[0013] As shown in Figure 1, the printer 100 includes a head module M, a paper feed roller 101, guide rollers 102A to 102C, a plurality of transport rollers 103, a recovery roller 104, a dryer 105, and a coating machine 106. Furthermore, the printer 100 includes a sensor unit 107 and a control unit 200. The head module M includes a plurality (for example, four) of liquid discharge heads 1 and a fixing plate 109.

[0014] The control unit 200 controls the operation of the multiple liquid discharge heads 1, paper feed roller 101, guide rollers 102A to 102C, multiple transport rollers 103, recovery roller 104, dryer 105, coating machine 106, and sensor unit 107 in the head module M.

[0015] The printer 100 records images or characters on the printing paper P by depositing droplets of liquid onto the paper P. The printing paper P is an example of a recording medium. Before use, the printing paper P is wound around the paper feed roller 101. The printer 100 then transports the printing paper P from the paper feed roller 101 to the coating machine 106 via the guide roller 102A.

[0016] The coating machine 106 uniformly applies the coating agent to the printing paper P. This allows the printing paper P to undergo surface treatment, thereby improving the print quality of the printer 100.

[0017] The printer 100 transports the coated printing paper P to the lower part of the head module M using transport rollers 103. The fixing plate 109 of the head module M is a rectangular flat plate and is located close to the upper part of the printing paper P being transported by the transport rollers 103.

[0018] The liquid discharge head 1 of the head module M is formed in an elongated shape such that the Y-axis direction is the longitudinal direction. Multiple liquid discharge heads 1 are fixed to a fixing plate 109. The liquid discharge heads 1 are fixed to the fixing plate 109 at both ends in the longitudinal direction, for example. The multiple liquid discharge heads 1 are positioned on the fixing plate 109 so as to be aligned along the transport direction (X-axis direction) of the printing paper P. Also, the liquid discharge heads 1 are positioned so that their longitudinal direction is perpendicular to the transport direction of the printing paper P. The distance between the liquid discharge head 1 and the printing paper P is, for example, about 0.5 to 20 mm. The configuration of the liquid discharge head 1 will be described later with reference to Figures 3 to 5.

[0019] The control unit 200 controls the liquid ejection head 1 based on image or text data (hereinafter sometimes referred to as "image data") and ejects droplets toward the printing paper P. More specifically, the liquid ejection head 1 includes a head control unit 10 (see Figure 3). The head control unit 10 controls the operation of the liquid ejection head 1 based on the image data input from the control unit 200, which will be described later.

[0020] As described above, the printer 100 according to this embodiment is a so-called line printer in which the liquid ejection head 1 is fixed inside the printer 100. However, the printer 100 according to this embodiment is not limited to a line printer, and may be a so-called serial printer. A serial printer is a printer that alternately performs the operation of recording while moving the liquid ejection head 1 in a direction intersecting the transport direction of the printing paper P, for example, in a nearly perpendicular direction, and transporting the printing paper P.

[0021] Each liquid ejection head 1 is supplied with liquid of the same color, and four liquid ejection heads 1 can print four different colors of liquid. The ink colors ejected from each liquid ejection head 1 are, for example, magenta (M), yellow (Y), cyan (C), and black (K). By depositing these liquids onto the printing paper P, the printer 100 can print a color image. The types and number of liquid colors can be changed as appropriate. For example, if the color to be printed on the printing paper P is a single color and the printing is limited to the area that can be printed by one liquid ejection head 1, then the printer 100 may only have one liquid ejection head 1. Alternatively, one liquid ejection head 1 may be supplied with several different colors of liquid, allowing one liquid ejection head 1 to print several different colors of liquid.

[0022] Furthermore, in addition to printing colored liquids, the printer 100 may also print a liquid such as a coating agent uniformly or in a pattern using the liquid ejection head 1 to treat the surface of the printing paper P. Alternatively, the printer 100 may apply the coating agent from a coating machine (not shown) instead of the liquid ejection head 1.

[0023] The printing paper P processed by the liquid discharge head 1 is transported by the transport roller 103 and guide roller 102B and passes through the inside of the dryer 105. The dryer 105 dries the printing paper P. The printing paper P dried in the dryer 105 is transported by the guide roller 102C and collected by the recovery roller 104. By drying in the dryer 105 in this way, it is possible to suppress the adhesion of overlapping printed paper sheets P to each other and friction of undried liquid at the recovery roller 104.

[0024] The sensor unit 107 is composed of a position sensor, a speed sensor, or a temperature sensor, etc. Based on the information from the sensor unit 107, the control unit 200 can determine the state of each part of the printer 100 and control each part of the printer 100.

[0025] The printer 100 may include a cleaning unit for cleaning the liquid ejection head 1. The cleaning unit cleans the liquid ejection head 1, for example, by wiping or capping.

[0026] The recording medium may be other than printing paper P, such as rolled cloth. The printer 100 may also transport the recording medium on a conveyor belt. In this way, the printer 100 can use sheets of paper, cut cloth, wood, or tiles as recording media. Furthermore, the printer 100 may print wiring patterns for electronic devices by ejecting a liquid containing conductive particles from the liquid ejection head 1. In addition, the printer 100 may produce chemical compounds by ejecting a predetermined amount of liquid chemical agent or a liquid containing a chemical agent from the liquid ejection head 1 towards a reaction vessel and allowing it to react.

[0027] <Regarding the configuration of the liquid dispensing head> Next, an example of the configuration of the liquid dispensing head 1 according to the embodiment will be described with reference to Figure 3. Figure 3 is a block diagram showing an example of the configuration of the liquid dispensing head 1.

[0028] As shown in Figure 3, the liquid discharge head 1 comprises a head control unit 10 and a plurality (for example, eight) discharge units 1A. Each discharge unit 1A is a discharge member that discharges liquid. Specifically, the liquid discharge head 1 is supplied with liquid, for example, ink, from a liquid tank (not shown), and discharges liquid (droplets). More specifically, each discharge unit 1A includes a liquid supply path, nozzles, piezoelectric elements, etc. (not shown). Liquid is supplied from the liquid tank to the liquid supply path. The piezoelectric element is, for example, a piezoelectric element (piezo element). The piezoelectric element deforms when a voltage is applied. As the piezoelectric element deforms, the discharge unit 1A discharges the liquid from the liquid supply path through the nozzles onto the printing paper P (see Figures 1 and 2).

[0029] The head control unit 10 controls the liquid discharge head 1. The head control unit 10 includes a control IC 11 and a drive IC 12.

[0030] The control IC 11 can communicate with the control unit 200 wirelessly or via a wired connection. The control IC 11 operates in accordance with various operation instructions input from the control unit 200. The control IC 11 is implemented by an integrated circuit such as an FPGA (Field Programmable Gate Array). Note that the control IC 11 is an example of the first IC.

[0031] Multiple drive ICs (for example, eight) are provided. More specifically, the number of drive ICs 12 is the same as the number of dispensing units 1A. Each of the multiple drive ICs 12 drives the corresponding dispensing unit 1A. Note that the drive IC 12 is an example of a second IC. The control IC 11 and the multiple drive ICs 12 are connected in a communicative manner via wiring 30 (see Figure 3), which will be described later.

[0032] The control IC 11 transmits various control signals to the drive IC 12, and the drive IC 12 operates based on the transmitted control signals. Specifically, the control IC 11 generates control signals based on image data input from the control unit 200 (see Figure 1) and outputs the generated control signals to the drive IC 12. When the drive IC 12 receives a control signal from the control IC 11, it generates a drive signal corresponding to the input control signal and outputs the generated drive signal to the discharge unit 1A. This drive signal applies a voltage to the piezoelectric element of the discharge unit 1A, causing it to deform and liquid to be discharged from the discharge unit 1A.

[0033] Here, a specific configuration example of the liquid discharge head 1 according to this embodiment will be described with reference to Figures 4 and 5. Figure 4 is a schematic plan view showing the liquid discharge head 1 according to this embodiment. Figure 5 is a schematic side view showing the liquid discharge head 1 according to this embodiment. Note that Figure 5 is a view of the liquid discharge head 1 shown in Figure 4 from the direction of arrow A.

[0034] As shown in Figures 4 and 5, the liquid discharge head 1 comprises a discharge section 1A, a base member 2, a head substrate 50, a flexible substrate 70, a control IC 11, and a drive IC 12. The base member 2 is formed in an elongated shape such that the Y-axis direction is the longitudinal direction. The base member 2 is a flat plate-shaped member.

[0035] The discharge unit 1A is attached and fixed to the lower surface of the base member 2. Specifically, as shown in Figure 4, four discharge units 1A are positioned in a staggered pattern in front of the printing paper P in the transport direction (positive X-axis direction), and four are positioned behind it. The discharge units 1A are positioned such that the centers of each liquid discharge head 1 do not overlap in the transport direction of the printing paper P.

[0036] The head board 50 is attached to and fixed to the base member 2. For example, the head board 50 is flat and formed in an elongated shape. The head board 50 is positioned on the base member 2 such that its longitudinal direction is along the Y-axis and is erected and fixed so as to extend in the positive Z-axis direction. The head board 50 is also positioned on the base member 2 so as to be near the center in the X-axis direction.

[0037] The head board 50 is equipped with a control IC 11. For example, the control IC 11 is positioned near the center of the head board 50 in the longitudinal direction (Y-axis direction). The control IC 11 is also positioned on the upper side (positive Z-axis direction) of the head board 50. Although not shown in the figures, the head board 50 is equipped with other electronic components for controlling the liquid discharge head 1 in addition to the control IC 11.

[0038] Flexible substrates 70 are electrically connected to the head substrate 50 via connectors (not shown). For example, a COF substrate (Chip on Film) can be used as the flexible substrate 70. There are multiple flexible substrates 70 (for example, eight). Each of the multiple flexible substrates 70 is mounted on a drive IC 12. Of the multiple flexible substrates 70, four are connected to one side 50a of the head substrate 50, and the other four are connected to the other side 50b of the head substrate 50. Specifically, the drive IC 12 mounted on the flexible substrates 70 drives the ejection unit 1A, as described above. Therefore, the flexible substrates 70 are positioned in a manner corresponding to the ejection unit 1A. Specifically, as shown in Figure 4, four flexible substrates 70 are positioned in a staggered pattern in front of the printing paper P in the transport direction (positive X-axis direction), and four are positioned behind it.

[0039] <Regarding Wiring> Next, we will describe the wiring 30 that connects the control IC 11 and the multiple drive ICs 12. Before describing the wiring 30 according to this embodiment, we will describe the wiring according to the prior art. Figure 11 is a diagram for illustrating the wiring according to the prior art. Figure 11 is a diagram that schematically represents the wiring topology of the connection relationship between the control IC 11 and the multiple drive ICs 12.

[0040] As shown in Figure 11, in the conventional technology, all drive ICs 12 are connected to the control IC 11 by fly-by wiring. In other words, all drive ICs 12 are connected to the control IC 11 in a daisy-chain configuration.

[0041] Specifically, the wiring connecting the control IC 11 and the multiple drive ICs 12 includes a wiring topology C, resistors D, and a branching section 40. The wiring topology C indicates the wiring through which the communication signal is transmitted. The resistors D are damping resistors, which, for example, suppress reflections in the output waveform from the control IC 11 and adjust the output waveform. In the prior art, each of the multiple (eight in this case) drive ICs 12 is connected to wiring branched at the branching section 40 and connected by fly-by wiring.

[0042] If the wiring is done in the same way as in conventional technology, the quality of the communication signal may deteriorate. Specifically, the output waveform of the communication signal output from the control IC 11 may become blunted. In other words, the output waveform of the communication signal from the control IC 11 tends to become blunted as the number of wiring branches increases or as the wiring length increases. Therefore, for example, the output waveform of the communication signal input to the drive IC 12x, which is located furthest from the control IC 11, will be blunted compared to the output waveform of the communication signal input to the drive IC 12y, which is located closest, and the quality of the communication signal may deteriorate.

[0043] Therefore, in this embodiment, the system is configured to improve the quality of the communication signals output from the control IC 11 to the multiple drive ICs 12.

[0044] Hereinafter, a specific configuration will be described with reference to FIG. 6 and the like. FIG. 6 is a diagram for explaining wiring according to the present embodiment. In the following description, the eight driver ICs 12 may be described as "first to eighth driver ICs 12a to 12h" for distinction, and when described without particular distinction, they are referred to as "driver ICs 12".

[0045] As shown in FIG. 6, the wiring 30 according to the present embodiment includes a first communication path 31 and a second communication path 32. The first communication path 31 and the second communication path 32 are configured to branch from a first branch portion 41 connected to the control IC 11. In other words, the first communication path 31 and the second communication path 32 are branched (in a T-shape) by a T-branch at the first branch portion 41.

[0046] In the first communication path 31, the first communication path 31 is connected to the driver IC 12 by fly-by wiring branched at a second branch portion 42. More specifically, the first communication path 31 includes first to fourth driver ICs 12a to 12d. In the first communication path 31, the first to fourth driver ICs 12a to 12d are each branched at the second branch portion 42, and the first to fourth driver ICs 12a to 12d are connected in a daisy chain. Specifically, of the two communication paths branched by the second branch portion 42 (excluding the second branch portion 42 farthest from the first branch portion 41), one has no branch point (branch portion) and the other has a branch point (branch portion), so that they are connected in a daisy chain. Further, of the two communication paths branched by the second branch portion 42, one has no resistor D and the other has a resistor D. Furthermore, of the two communication paths branched by the second branch portion 42, one has a shorter wiring length from the second branch portion 42 to the driver IC 12 than the other. For example, the wiring length from the second branch portion 42a to the fourth driver IC 12d is shorter than the wiring length from the second branch portion 42a to the first, second, and third driver ICs 12a, 12b, 12c.

[0047] In the second communication path 32, connection to the driving ICs 12 is achieved through fly-by wiring branched at the second branching portions 42. Specifically, the second communication path 32 includes the fifth to eighth driving ICs 12e to 12h. In the second communication path 32, the fifth to eighth driving ICs 12e to 12h are each branched at the second branching portions 42, and the fifth to eighth driving ICs 12e to 12h are connected in a daisy chain.

[0048] As described above, in the wiring 30 according to the present embodiment, the first communication path 31 and the second communication path 32 are each connected to the driving ICs 12 by fly-by wiring in which the communication path branches at the second branching portions 42. Specifically, the eight driving ICs 12 are divided into two groups: the first to fourth driving ICs 12a to 12d, and the fifth to eighth driving ICs 12e to 12h, such that the first to fourth driving ICs 12a to 12d and the fifth to eighth driving ICs 12e to 12h are each connected by fly-by wiring.

[0049] Thereby, the number of branches in the wiring extending from the control IC 11 to the first and eighth driving ICs 12a and 12h located at the farthest position can be made smaller than the number of branches in the wiring extending to the driving IC 12x (see FIG. 11) located at the farthest position in the prior art. Further, the wiring length from the control IC 11 to the first and eighth driving ICs 12a and 12h located at the farthest position can be made shorter than the wiring length to the driving IC 12x (see FIG. 11) located at the farthest position in the prior art. Thereby, the output waveform of the communication signal input to each driving IC 12 including the first and eighth driving ICs 12a and 12h can be made less prone to dullness, and as a result, the quality of the communication signal can be improved.

[0050] Further, when all driving ICs 12 are connected by fly-by wiring as in the prior art, eight resistors D are required (see FIG. 11). However, if the wiring 30 according to the present embodiment is used, the number of resistors D can be reduced to seven, enabling cost reduction.

[0051] Furthermore, in this embodiment, there is only one first branch 41. The second branch 42 in the first communication path 31 and the second branch 42 in the second communication path 32 are connected to this single first branch 41. As a result, as described above, it is possible to reduce the number of resistors D, thereby reducing costs.

[0052] Furthermore, the wiring length from the control IC 11 to the first communication path 31 and the wiring length from the control IC 11 to the second communication path 32 are configured to be equal in length. Specifically, the wiring length from the first branch 41 connected to the control IC 11 to the second branch 42 of the first communication path 31 (for example, the second branch 42a closest to the first branch 41) and the wiring length from the first branch 41 to the second branch 42 of the second communication path 32 (for example, the second branch 42b closest to the first branch 41) are configured to be equal in length.

[0053] Preferably, the wiring length from the first branch 41 connected to the control IC 11 to the drive IC 12 of the first communication path 31 (for example, the fourth drive IC 12d closest to the first branch 41) and the wiring length from the first branch 41 to the drive IC 12 of the second communication path 32 (for example, the fifth drive IC 12e closest to the first branch 41) are configured to be equal in length.

[0054] Preferably, the wiring length from the first branch 41 connected to the control IC 11 to the drive IC 12 of the first communication path 31 (for example, the first drive IC 12a furthest from the first branch 41) and the wiring length from the first branch 41 to the drive IC 12 of the second communication path 32 (for example, the eighth drive IC 12h furthest from the first branch 41) are configured to be equal in length.

[0055] In this way, by configuring the wiring length from the control IC 11 to be equal in length between the first communication path 31 and the second communication path 32, it becomes possible to maintain the same quality of communication signals in the first communication path 31 and the second communication path 32.

[0056] Furthermore, the term "equal length" as described above does not require that the two wiring lengths be identical; a certain degree of difference in wiring length is acceptable. For example, if the length of one wiring is in the range of 0.5 to 2 times the length of the other wiring, then the two wiring lengths are considered to be of equal length.

[0057] <Regarding the mounting example of the circuit board> Next, an example of mounting the control IC 11 and the drive IC 12 on the circuit board will be explained with reference to Figures 7 and 8. Figure 7 is a side view showing an example of mounting the control IC 11 and the drive IC 12 on the circuit board. Figure 8 is a top view of the circuit board on which the control IC 11 is mounted.

[0058] Note that while Figures 7 and 8 show a Cartesian coordinate system, this Cartesian coordinate system is for illustrative purposes only and does not limit the orientation or direction of placement of substrates, etc.

[0059] As shown in Figures 7 and 8, the control IC 11 is mounted on the head board 50. The head board 50 is formed, for example, in the shape of a flat plate. The head board 50 has a first surface 50a and a second surface 50b opposite to the first surface 50a. The control IC 11 is mounted on the first surface 50a of the head board 50. Note that the head board 50 is an example of a wiring board.

[0060] The drive IC 12 is mounted on a flexible substrate 70, such as a COF substrate (Chip on Film). The drive IC 12 outputs a drive signal to the output unit 1A (see Figure 3) via the flexible substrate. Multiple flexible substrates 70 are provided (for example, eight). More specifically, the same number of flexible substrates 70 as the number of drive ICs 12 are provided. One drive IC 12 is mounted on each of the multiple flexible substrates 70. The multiple flexible substrates 70 include multiple (for example, four) first flexible substrates 70a and multiple (for example, four) second flexible substrates 70b, which will be described later.

[0061] The control IC 11 mounted on the head board 50 and the drive IC 12 mounted on the flexible board 70 are communicated via connectors 51a, 51b, 71a, and 71b. Specifically, there are multiple (for example, four) connectors 51a and 51b, which are mounted on the head board 50. Connector 51a is mounted on the first surface 50a of the head board 50, and connector 51b is mounted on the second surface 50b of the head board 50. Connectors 51a and 51b are arranged so as to be aligned along the Y-axis direction in a side view (see Figure 7). Note that the Y-axis direction is an example of a first direction. On the head board 50, when viewed from the Y-axis direction, connectors 51a and connector 51b are arranged alternately.

[0062] Connectors 51a and 51b are connected to the control IC 11 via the wiring 30 shown in Figure 6, enabling communication. Figure 7 shows some of the wiring 30, including the communication paths 61 and 62, the first branch 41, and the second branch 42.

[0063] There are multiple connectors 71a and 71b (for example, four) and they are provided on the flexible substrate 70. Specifically, connector 71a is provided on the first flexible substrate 70a, and connector 71b is provided on the second flexible substrate 70b.

[0064] As described above, the connector 51a of the head board 50 and the connector 71a of the first flexible board 70a are connected, thereby electrically connecting the control IC 11 of the head board 50 and the drive IC 12 of the first flexible board 70a. Additionally, the connector 51b of the head board 50 and the connector 71b of the second flexible board 70b are connected, thereby electrically connecting the control IC 11 of the head board 50 and the drive IC 12 of the second flexible board 70b. More specifically, the first flexible board 70a is electrically connected to the first surface 50a of the head board 50 and connected to the drive IC 12. The second flexible board 70b is electrically connected to the second surface 50b and connected to the drive IC 12.

[0065] Here, the position where the control IC 11 is located will be explained in detail. As shown in Figure 7, the multiple drive ICs 12 are arranged to be located along the Y-axis direction (first direction; see dashed line E). The control IC 11 is located in a region B defined between a drive IC 12 located at one end along the Y-axis direction (here, the first drive IC 12a) and a drive IC 12 located at the other end along the Y-axis direction (here, the eighth drive IC 12h). Specifically, region B is defined as the area of ​​the head substrate 50 corresponding to the imaginary line F1 extending in the Z-axis direction from the end of the drive IC 12 located at one end (the first drive IC 12a) and an imaginary line F2 extending in the Z-axis direction from the end of the drive IC 12 located at the other end (the eighth drive IC 12h), and the control IC 11 is located in this region B.

[0066] More specifically, region B is divided into four partitioned regions B1, B2, B3, and B4 aligned in the Y-axis direction. The control IC 11 is positioned in the central partitioned regions B2 and B3 of these four partitioned regions B1, B2, B3, and B4. Specifically, the control IC 11 is positioned across the central partitioned regions B2 and B3. Note that while Figure 7 shows an example where the control IC 11 is positioned in partitioned regions B2 and B3, it is not limited to this; it may also be positioned in partitioned region B2 or partitioned region B3. In other words, the control IC 11 only needs to be positioned in at least one of the two central partitioned regions B2 and B3 of the four partitioned regions B1, B2, B3, and B4.

[0067] As a result, the wiring 30 extending from the control IC 11 is branched at the first branching section 41, but by positioning the control IC 11 in the central divided regions B2 and B3, the wiring 30 branched from the first branching section 41 can be prevented from becoming densely packed. Furthermore, by positioning the control IC 11 in the central divided regions B2 and B3, the design flexibility of the wiring routes can be improved for the wiring 30 branched from the first branching section 41 and for other wiring not shown.

[0068] Furthermore, as described above, the control IC 11 and wiring 30 are arranged on the head board 50. The multiple drive ICs 12 are each mounted on multiple flexible boards 70. By using the flexible boards 70 in this way, it becomes possible to easily electrically connect the control IC 11 and the drive ICs 12 on the head board 50.

[0069] Furthermore, the multiple flexible substrates 70 are arranged so as to be positioned along the Y-axis. Also, when viewed from the Y-axis direction, the first flexible substrate 70a and the second flexible substrate 70b are arranged alternately. The wiring 30 is electrically connected to the first and second flexible substrates 70a and 70b configured as described above. Specifically, one of the communication paths branched at the second branching section 42 of the wiring 30, communication path 61, is electrically connected to the first flexible substrate 70a. The other communication path branched at the second branching section 42, communication path 62, is electrically connected to the second flexible substrate 70b which is aligned in the Y-axis direction with respect to the second flexible substrate 70b.

[0070] More specifically, the communication path 61 is located on the first surface 50a of the head substrate 50 and is electrically connected to the first flexible substrate 70a. The communication path 62 is located on the second surface 50b of the head substrate 50 via a through hole 52 provided in the head substrate 50 and is electrically connected to the second flexible substrate 70b. The through hole 52 is a via hole that electrically connects the first surface 50a and the second surface 50b of the head substrate 50, but is not limited to this.

[0071] By configuring the communication paths 61 and 62 as described above, the wiring length to the drive IC 12 in the wiring branched at the second branching section 42 can be made as short as possible, thereby reducing the effect of reflection on the communication signal.

[0072] Furthermore, the first flexible substrate 70a and the second flexible substrate 70b are arranged alternately, with the first flexible substrate 70a connected to the first surface 50a of the head substrate 50 and the second flexible substrate 70b connected to the second surface 50b. This makes it possible to shorten the wiring length to the drive IC 12 in the wiring branched at the second branching section 42 as much as possible, thereby reducing the effect of reflection on the communication signal.

[0073] In the above example, the first surface 50a and the second surface 50b are located in the outer layer of the head substrate 50, but the invention is not limited to this, and at least one of the first surface 50a and the second surface 50b may be configured to be located in the inner layer of the head substrate 50.

[0074] Furthermore, while the above example shows the region B where the control IC 11 is located being divided into four divided regions B1, B2, B3, and B4, it is not limited to this. Here, other examples of divided regions in region B will be explained with reference to Figure 9. Figure 9 is a diagram showing other examples of divided regions in region B.

[0075] As shown in Figure 9, region B is divided into three partitioned regions B1a, B2a, and B3a aligned in the Y-axis direction. The control IC 11 is positioned in the central partitioned region B2a of these three partitioned regions B1a, B2a, and B3a.

[0076] As a result, the wiring 30 extending from the control IC 11 is branched at the first branching section 41, but by positioning the control IC 11 in the central divided region B2a, the wiring 30 branched from the first branching section 41 can be prevented from becoming densely packed. Furthermore, by positioning the control IC 11 in the central divided region B2a, the design flexibility of the wiring routes can be improved for the wiring 30 branched from the first branching section 41 and for other wiring not shown.

[0077] As described above, the liquid discharge head 1 according to this embodiment includes a control IC 11, a drive IC 12, and wiring 30. The multiple drive ICs 12 drive a discharge unit 1A that discharges liquid based on communication signals from the control IC 11. The wiring 30 connects the control IC 11 and the multiple drive ICs 12 in a communicative manner. The wiring 30 includes a first communication path 31 and a second communication path 32 that branch off from a first branching section 41 connected to the control IC 11. The first communication path 31 and the second communication path 32 are each connected to the drive IC 12 by fly-by wiring where the communication path branches off at the second branching section 42. This makes it possible to improve the quality of communication signals in the liquid discharge head 1.

[0078] <Regarding Modified Examples> Next, the wiring 30 in the liquid discharge head 1 according to the modified example will be described with reference to Figure 10. Figure 10 is a diagram illustrating the wiring 30 according to the modified example. In the following, components common to the embodiment may be denoted by the same reference numerals and their descriptions may be omitted.

[0079] As shown in Figure 10, in the modified configuration, one control IC 11 is provided with 16 drive ICs 12. The first communication path 31 includes a third communication path 33 and a fourth communication path 34. The third communication path 33 and the fourth communication path 34 are configured to branch from the third branch 43, which is connected to the first branch 41. In other words, the third communication path 33 and the fourth communication path 34 branch off at the third branch 43 by a T-branch (in a T-shape).

[0080] In the third communication path 33, the drive IC 12 is connected by fly-by wiring that branches off at the second branching section 42. More specifically, the third communication path 33 includes the first to fourth drive ICs 12a to 12d. In the third communication path 33, the first to fourth drive ICs 12a to 12d each branch off at the second branching section 42, and the first to fourth drive ICs 12a to 12d are connected in a daisy-chain configuration.

[0081] In the fourth communication path 34, the drive IC 12 is connected by fly-by wiring that branches off at the second branching section 42. More specifically, the fourth communication path 34 includes the fifth to eighth drive ICs 12e to 12h. In the fourth communication path 34, the fifth to eighth drive ICs 12e to 12h each branch off at the second branching section 42, and the fifth to eighth drive ICs 12e to 12h are connected in a daisy-chain configuration.

[0082] The second communication path 32 includes a fifth communication path 35 and a sixth communication path 36. The fifth communication path 35 and the sixth communication path 36 are configured to branch from a fourth branch 44 connected to the first branch 41. In other words, the fifth communication path 35 and the sixth communication path 36 branch off at the fourth branch 44 by a T-branch (in a T-shape).

[0083] In the fifth communication path 35, the drive IC 12 is connected by fly-by wiring that branches off at the second branching section 42. More specifically, the fifth communication path 35 includes the ninth to twelfth drive ICs 12i to 12l. In the fifth communication path 35, the ninth to twelfth drive ICs 12i to 12l each branch off at the second branching section 42, and the ninth to twelfth drive ICs 12i to 12l are connected in a daisy-chain configuration.

[0084] In the sixth communication path 36, the drive IC 12 is connected by fly-by wiring that branches off at the second branching section 42. More specifically, the sixth communication path 36 includes the 13th to 16th drive ICs 12m to 12p. In the sixth communication path 36, the 13th to 16th drive ICs 12m to 12p each branch off at the second branching section 42, and the 13th to 16th drive ICs 12m to 12p are connected in a daisy-chain configuration.

[0085] Thus, in this modified example, the third to sixth communication paths 33 to 36 are each connected to the drive IC 12 by fly-by wiring, where the communication path branches at the second branching point 42. Specifically, the 16 drive ICs 12 are divided into two halves: the first to eighth drive ICs 12a to 12h and the ninth to sixteenth drive ICs 12i to 12p. Furthermore, the first to eighth drive ICs 12a to 12h are divided into two halves: the first to fourth drive ICs 12a to 12d and the fifth to eighth drive ICs 12e to 12h. Also, the ninth to sixteenth drive ICs 12i to 12p are divided into two halves: the ninth to twelfth drive ICs 12i to 12l and the thirteenth to sixteenth drive ICs 12m to 12p. Furthermore, the first to fourth drive ICs 12a to 12d, the fifth to eighth drive ICs 12e to 12h, the ninth to twelfth drive ICs 12i to 12l, and the thirteenth to sixteenth drive ICs 12m to 12p are connected by fly-by wiring.

[0086] This reduces the number of branches in the wiring from the control IC 11 to the 4th, 8th, 12th, and 16th drive ICs 12d, 12h, 12l, and 12p, which are located furthest from the control IC 11, compared to a configuration where all drive ICs 12 are connected by fly-by wiring. Furthermore, the wiring length from the control IC 11 to the 4th, 8th, 12th, and 16th drive ICs 12d, 12h, 12l, and 12p, which are located furthest from the control IC 11, can be shortened compared to a configuration where all drive ICs 12 are connected by fly-by wiring. This makes it less likely for the output waveform of the communication signal input to each drive IC 12, including the 4th, 8th, 12th, and 16th drive ICs 12d, 12h, 12l, and 12p, to be distorted, resulting in improved communication signal quality.

[0087] In the embodiments and modifications described above, the communication path is branched into two communication paths at the first branching section 41, the third branching section 43, and the fourth branching section 44, but the invention is not limited to this, and for example, it may be branched into three or more communication paths.

[0088] Furthermore, the following additional information is disclosed with respect to the above embodiments. <Additional Information> (1) A liquid dispensing head comprising: a first IC; a plurality of second ICs that drive a dispensing unit for dispensing liquid based on a communication signal from the first IC; and wiring that connects the first IC and the plurality of second ICs in a communicative manner, wherein the wiring includes a first communication path and a second communication path that branch off from a first branch connected to the first IC, and the first communication path and the second communication path are each connected to the second IC by fly-by wiring where the communication path branches off at the second branch. (2) The liquid dispensing head according to (1), wherein there is one first branch, and the second branch in the first communication path and the second branch in the second communication path are connected to the first branch. (3) The liquid dispensing head according to (1), wherein the first communication path includes a third communication path and a fourth communication path branching from a third branch connected to the first branch, and the second communication path includes a fifth communication path and a sixth communication path branching from a fourth branch connected to the first branch, and the third to sixth communication paths are each connected to the second IC by fly-by wiring where the communication path branches at the second branch. (4) The liquid dispensing head according to any one of (1) to (3), wherein a plurality of the second ICs are arranged to be located along a first direction, and the first ICs are arranged to be located in a region defined between the second IC located on one end side of the first direction and the second IC located on the other end side of the first direction. (5) The liquid dispensing head according to (4), wherein the region is divided into four divided regions arranged in the first direction, and the first IC is positioned in at least one of the two central divided regions among the four divided regions. (6) The liquid dispensing head according to (4), wherein the region is divided into three divided regions arranged in the first direction, and the first IC is positioned in the central divided region among the three divided regions.(7) A liquid dispensing head according to any one of (1) to (6), further comprising a wiring board and a plurality of flexible boards electrically connected to the wiring board, wherein the first IC and the wiring are arranged on the wiring board, and each of the plurality of second ICs is mounted on the plurality of flexible boards. (8) A liquid dispensing head according to (7), wherein the wiring board has a first surface and a second surface opposite to the first surface, and the plurality of flexible boards are arranged to be located along a first direction, and further include a plurality of first flexible boards electrically connected to the first surface and a plurality of second flexible boards electrically connected to the second surface, wherein when viewed from the first direction, the first flexible boards and the second flexible boards are arranged alternately, one of the communication paths branched at the second branch is electrically connected to the first flexible board, and the other of the communication paths branched at the second branch is electrically connected to the second flexible boards aligned in the first direction with respect to the first flexible board. (9) The liquid dispensing head according to (8), wherein one of the communication paths is arranged on the first surface of the wiring board, and the other of the communication paths is arranged on the second surface of the wiring board through a through hole provided in the wiring board.

[0089] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the appended claims.

[0090] 1 Liquid ejection head 1A Discharge unit 11 Control IC 12 Drive IC 31 First communication path 32 Second communication path 41 First branching section 42 Second branching section 100 Printer

Claims

1. A liquid dispensing head comprising: a first IC; a plurality of second ICs that drive a dispensing unit for dispensing liquid based on a communication signal from the first IC; and wiring that enables communication between the first IC and the plurality of second ICs, wherein the wiring includes a first communication path and a second communication path branching from a first branching section connected to the first IC, and the first communication path and the second communication path are each connected to the second IC by fly-by wiring where the communication path branches at the second branching section.

2. The liquid dispensing head according to claim 1, wherein there is one first branching portion, and the second branching portion in the first communication path and the second branching portion in the second communication path are connected to the first branching portion.

3. The liquid dispensing head according to claim 1, wherein the first communication path includes a third communication path and a fourth communication path branching from a third branch connected to the first branch, the second communication path includes a fifth communication path and a sixth communication path branching from a fourth branch connected to the first branch, and the third to sixth communication paths are each connected to the second IC by fly-by wiring where the communication path branches at the second branch.

4. The liquid dispensing head according to any one of claims 1 to 3, wherein a plurality of the second ICs are arranged to be located along a first direction, and the first ICs are arranged to be located in a region defined between the second IC located at one end of the first direction and the second IC located at the other end of the first direction.

5. The liquid dispensing head according to claim 4, wherein the region is divided into four divided regions arranged in the first direction, and the first IC is positioned in at least one of the two central divided regions among the four divided regions.

6. The liquid dispensing head according to claim 4, wherein the region is divided into three divided regions arranged in the first direction, and the first IC is positioned in the central divided region of the three divided regions.

7. A liquid dispensing head according to any one of claims 1 to 6, further comprising a wiring board and a plurality of flexible boards electrically connected to the wiring board, wherein the first IC and the wiring are arranged on the wiring board, and the plurality of second ICs are each mounted on the plurality of flexible boards.

8. The liquid dispensing head according to claim 7, wherein the wiring board has a first surface and a second surface opposite to the first surface, and the plurality of flexible boards are arranged to be located along a first direction, and further include a plurality of first flexible boards electrically connected to the first surface and a plurality of second flexible boards electrically connected to the second surface, and when viewed from the first direction, the first flexible boards and the second flexible boards are arranged alternately, one of the communication paths branched at the second branch is electrically connected to the first flexible board, and the other of the communication paths branched at the second branch is electrically connected to the second flexible boards aligned in the first direction with respect to the first flexible board.

9. The liquid dispensing head according to claim 8, wherein one of the communication paths is arranged on the first surface of the wiring board, and the other of the communication paths is arranged on the second surface of the wiring board through a through hole provided in the wiring board.

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