Liquid dispensing device

Abstract

To suppress noise interference in a relay substrate and suppress increase in the length of a wiring connected to a liquid discharge head from the relay substrate and that of a wiring connected to a valve from the relay substrate.SOLUTION: A printer comprises: an ink jet head; an electromagnetic valve provided above the ink jet head; a control unit having a control board 7; a relay substrate 80; and an FPC 8 connecting the control board 7 with the relay substrate 80. The relay substrate 80 is vertically installed along a vertical direction A1. The FPC 8 comprises a plurality of signal lines 8a for the head, and a signal line 8b for the valve. A position of connection of the signal line 8b for the valve to the relay substrate 80 is above positions of connection of the signal lines 8a for the head to the relay substrate 80.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection device having an electrically operated valve that can selectively take either a connected state in which an atmosphere communication passage is connected to connect a liquid storage chamber connected to a liquid ejection head with the outside, or a blocked state in which the atmosphere communication passage is blocked. [Background technology]

[0002] Patent Document 1 describes an inkjet recording device in which ink supplied from an ink tank is stored in an ink buffer and ejected from a print head on a carriage onto a recording medium to perform a recording operation. In this inkjet recording device, an air release electromagnetic valve that controls communication between the upper air layer in the ink buffer and the atmosphere is open while ink is being supplied from the ink tank into the ink buffer. This allows air in the upper part of the ink buffer to escape during ink supply, preventing the ink in the ink buffer from becoming pressurized. Furthermore, in this inkjet recording device, during purging, the air release electromagnetic valve is closed, and pressurized ink is supplied from the ink tank to perform the purging operation. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication number 01-040681 Summary of the Invention [Problem to be solved by the invention]

[0004] Thus, while Patent Document 1 describes an inkjet recording device having an atmosphere venting electromagnetic valve, it does not describe the arrangement of a control board for controlling the atmosphere venting electromagnetic valve and print head, and the signal lines connecting the atmosphere venting electromagnetic valve and print head. If the atmosphere venting electromagnetic valve and print head are connected to a relay board, and the atmosphere venting electromagnetic valve and print head are connected to a control board via the relay board, a valve signal line for sending signals from the control board to the atmosphere venting electromagnetic valve and a head signal line for sending signals from the control board to the print head are connected to connect the control board to the relay board.

[0005] For example, if the atmosphere venting electromagnetic valve is located above the print head and the relay board is installed so as to intersect with the horizontal plane (e.g., vertically), and the connection position of the valve signal line to the relay board is located below the connection position of the head signal line to the relay board, if the valve wiring connected to the valve signal line is formed within the relay board upward so as to approach the atmosphere venting electromagnetic valve, and the head wiring connected to the head signal line is formed downward so as to approach the print head, the two wirings will be more likely to cross, making noise interference more likely. On the other hand, if the valve wiring and head wiring are arranged within the relay board so as not to cross each other, at least one of the distance from the connection position of the wiring connecting the relay board and the atmosphere venting electromagnetic valve to the relay board to the atmosphere venting electromagnetic valve and the distance from the connection position of the wiring connecting the relay board and the print head to the relay board to the print head will be longer, and the wiring length corresponding to the longer distance will also be longer.

[0006] Furthermore, if the atmosphere vent electromagnetic valve is located upstream of the print head in the transport direction of the recording medium, and the relay board is installed so as to intersect with a vertical plane facing the transport direction (for example, horizontally), and the connection position of the valve signal line to the relay board is located downstream in the transport direction of the head signal line to the relay board, if the valve wiring connected to the valve signal line is formed within the relay board upstream in the transport direction so as to approach the atmosphere vent electromagnetic valve, and the head wiring connected to the head signal line is formed downstream in the transport direction so as to approach the print head, the two wirings are likely to cross, making noise interference more likely. On the other hand, if the valve wiring and the head wiring are arranged within the relay board so as not to cross each other, at least one of the distance from the connection position of the wiring connecting the relay board and the atmosphere vent electromagnetic valve to the relay board to the atmosphere vent electromagnetic valve and the distance from the connection position of the wiring connecting the relay board and the print head to the relay board to the print head will be longer, and the wiring length corresponding to the longer distance will also be longer.

[0007] Thus, depending on the relationship between the connection position of the valve signal line to the relay board, the connection position of the head signal line to the relay board, and the positions of the atmosphere venting electromagnetic valve and the print head, at least one of the problems of noise interference occurring within the relay board and the wiring connecting the relay board to the atmosphere venting electromagnetic valve and the wiring connecting the relay board to the print head becoming longer may occur.

[0008] Therefore, an object of the present invention is to provide a liquid ejection device that can suppress noise interference within the relay substrate and prevent the wiring connecting from the relay substrate to the liquid ejection head and the wiring connecting from the relay substrate to the valve from becoming too long. [Means for solving the problem]

[0009] The liquid ejection device of the present invention comprises a transport mechanism that transports a recording medium in a transport direction, a liquid ejection head having a nozzle that ejects liquid, a liquid storage chamber that stores liquid, an atmosphere communication passage that connects the liquid storage chamber to the outside, and a liquid storage section that has an electrically driven valve that can selectively take either a communication state that connects the atmosphere communication passage or a blockage state that blocks the atmosphere communication passage, a liquid flow path that connects the liquid ejection head and the liquid storage chamber so that liquid can flow through, a control unit that has a control board and controls the liquid ejection head, the valve, and the transport mechanism, a relay board that is installed intersecting a vertical plane facing the transport direction, a head signal line that is connected to connect the control board and the relay board and that transmits a signal from the control board to the liquid ejection head, and a valve signal line that is connected to connect the control board and the relay board and that transmits a signal from the control board to the valve. The valve is positioned on one side of the transport direction relative to the liquid ejection head, and the connection position of the valve signal line to the relay board is on the one side of the transport direction relative to the connection position of the head signal line to the relay board. [Effects of the Invention]

[0010] According to the liquid ejection device of the present invention, the connection positions of the valve signal lines to the relay substrate are closer to the valves, and the connection positions of the head signal lines to the relay substrate are closer to the liquid ejection head. This eliminates the need to cross the valve wiring connected to the valve signal lines and the head wiring connected to the head signal lines within the relay substrate, thereby suppressing noise interference. It also makes it possible to prevent the wiring connecting from the relay substrate to the liquid ejection head and the wiring connecting from the relay substrate to the valves from becoming too long. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic perspective view of a printer according to an embodiment of the present invention; [Figure 2] FIG. 2 is a vertical cross-sectional view schematically showing the internal structure of the printer shown in FIG. [Figure 3] 3 shows the ink tank and inkjet head shown in FIG. 2, where (a) is a front view and (b) is a side view. [Figure 4] FIG. 4 is a plan view of the inkjet head shown in FIG. [Figure 5] FIG. 6 is a cross-sectional view taken along the line VI-VI shown in FIG. [Figure 6] FIG. 1 is a schematic diagram showing the installation of a control board, a relay board, and an FPC connecting these boards. [Figure 7] FIG. 2 is a block diagram showing the electrical configuration of the printer in FIG. [Figure 8] 4 is a flowchart showing a recording operation of the printer. [Figure 9] 10 is a flowchart showing the operation of the printer when the liquid level sensor detects that the liquid level is empty. [Figure 10] FIG. 1(a) shows a side view of the ink tank and inkjet head of a printer according to a first modified example, and FIG. 1(b) is a schematic diagram showing the installation of the control board, relay board, and FPC connecting these two boards of the printer according to the first modified example. [Figure 11] FIG. 10A shows a side view of the ink tank and inkjet head of a printer according to a second modified example, and FIG. 10B is a schematic diagram showing the installation of the control board, relay board, and FPC connecting these two boards of the printer according to the second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] A printer 1 according to one embodiment of the present invention will be described below. The printer 1 is installed and used in the state shown in Fig. 1. In this embodiment, the three directions indicated by arrows in Fig. 1 are the up-down direction A1, the front-rear direction A2, and the left-right direction A3. Figs. 2 to 6 also reflect and show the three directions shown in Fig. 1.

[0013] <Printer 1 Overview> As shown in FIG. 1, the printer 1 has a housing 11 that is roughly rectangular parallelepiped. An opening 12 is formed in the approximate center of a front wall 11a of the housing 11. A paper feed tray 15 and a paper output tray 16 are provided in the opening 12, one above the other. The paper feed tray 15 is insertable into and removable from the opening 12 in the front-rear direction A2, i.e., it is detachable from the housing 11. Paper P of a desired size (e.g., A4 size) is placed on the paper feed tray 15. The printer 1 can be connected to an external device such as a personal computer (hereinafter referred to as a PC). The printer 1 then performs a printing operation based on print data from the PC or the like.

[0014] 1, an operation unit 13 is provided on the upper part of the front wall 11a. The operation unit 13 is composed of buttons operated for various settings, a liquid crystal display that displays various information, etc. In this embodiment, the operation unit 13 is composed of a touch panel that has the functions of both buttons and a liquid crystal display.

[0015] 1 and 2, the housing 11 has an opening / closing cover 14 that forms its ceiling portion. The opening / closing cover 14 is configured to be rotatable at its rear end about a rotation axis (not shown) that extends in the left-right direction A3. By opening the opening / closing cover 14, an ink tank 61 (described below) is exposed, allowing ink to be poured into the ink tank 61 for refilling.

[0016] <Internal structure of Printer 1> Next, we will explain the internal structure of the printer 1. As shown in Figure 2, the printer 1 includes a feeding unit 20, a pair of transport rollers 35, a recording unit 40, a pair of paper discharge rollers 36, an ASF (Auto Sheet Feed) motor 20M (see Figure 7), an LF (Line Feed) motor 35M (see Figure 7), a liquid level sensor 6 (see Figure 7), and a control unit 5 (see Figure 7).

[0017] 2, the feeding unit 20 feeds the paper P placed on the paper feed tray 15 to the conveying path 25. The conveying roller pair 35 conveys the paper P fed by the feeding unit 20 to the recording unit 40. The recording unit 40 has, for example, an inkjet recording configuration, and records an image on the paper P conveyed by the conveying roller pair 35. The paper discharge roller pair 36 discharges the paper P recorded by the recording unit 40 to the paper discharge tray 16.

[0018] <Feeding section 20> As shown in FIG. 2, the feeding unit 20 is provided above the paper feed tray 15. The feeding unit 20 has a paper feed roller 21 and an arm 22. The paper feed roller 21 is axially supported at the tip of the arm 22. The arm 22 is rotatably supported on a support shaft 22a and is biased by a spring or the like to rotate the paper feed roller 21 downward so that the paper feed roller 21 comes into contact with the paper feed tray 15. The arm 22 is also configured to be able to retract upward when the paper feed tray 15 is attached or detached. The paper feed roller 21 is rotated by the power of the ASF motor 20M transmitted via a transmission mechanism (not shown), and the paper P stacked in the paper feed tray 15 is fed to the conveying path 25.

[0019] <Paper Tray 15> 2, the paper feed tray 15 has an inclined wall portion 15a. The inclined wall portion 15a guides the paper P placed on the paper feed tray 15 to the conveyance path 25 when the paper P is fed by the paper feed roller 21.

[0020] <Transport path 25> The transport path 25 is configured inside the housing 11, and as shown in Figure 2, it bends upward from the rear end of the paper feed tray 15 and toward the front of the printer 1. The paper P fed from the paper feed tray 15 is guided by the transport path 25 in a U-turn from below to above, and reaches the recording unit 40.

[0021] <Pair of conveying rollers 35 and pair of paper ejection rollers 36> The conveying roller pair 35 has a conveying roller 35a disposed on the lower side and a pinch roller 35b disposed on the upper side. The conveying roller 35a is rotated by the power of the LF motor 35M transmitted via a transmission mechanism (not shown). The pinch roller 35b rotates in conjunction with the rotation of the conveying roller 35a. The conveying roller 35a and the pinch roller 35b cooperate to sandwich the paper P from above and below in the direction A1 and convey the paper P to the recording unit 40.

[0022] The pair of discharge rollers 36 has a lower discharge roller 36a and an upper spur roller 36b. The discharge roller 36a rotates by receiving power from the LF motor 35M via a transmission mechanism (not shown). The spur roller 36b rotates in conjunction with the rotation of the discharge roller 36a. The discharge roller 36a and the spur roller 36b cooperate to sandwich the paper P from above and below in the direction A1 and transport the paper P to the discharge tray 16.

[0023] <Recording Unit 40> As shown in FIGS. 2 and 3 , the recording unit 40 has an inkjet head 41, an ink tank 61, an intermediate board 80, a carriage 70, a moving mechanism 71, and a platen 17. The carriage 70 moves back and forth in the scanning direction (the left-right direction A3, a direction perpendicular to the transport direction of the paper P). The inkjet head 41 and the ink tank 61 are supported by the carriage 70. In other words, the printer 1 in this embodiment is a so-called on-carriage type in which the ink tank 61 and the inkjet head 41 are mounted on the carriage 70. In this embodiment, the ink tank 61 is entirely located above the inkjet head 41. However, this is not limiting, and a portion of the ink tank 61 may be located above the top surface of the inkjet head 41, and the remaining portion may be located below the top surface.

[0024] <Ink Tank 61> As shown in FIG. 3, the ink tank 61 has a tank body 62, a cap 63, and an electromagnetic valve 64. The tank body 62 has a substantially rectangular parallelepiped shape, and has an ink storage chamber 62a formed therein for storing ink. Black ink is stored in the ink storage chamber 62a. The tank body 62 is made primarily of a light-transmitting material (for example, a transparent or translucent resin). This allows the user to visually check the amount of ink in the ink storage chamber 62a.

[0025] As shown in FIG. 3, the tank body 62 has a through-hole 62c formed through its upper wall 62b. The through-hole 62c is located in the center of the upper wall 62b in the left-right direction A3, slightly toward the front. A cylindrical body 66 is fitted into the through-hole 62c. The cylindrical body 66 has an ink inlet 67 at its upper end. The ink inlet 67 is an opening that opens upward (i.e., toward the outside). The inner circumferential surface of the cylindrical body 66 defines an ink supply path 66a that runs from the ink inlet 67 to the ink storage chamber 62a. This allows the ink inlet 67 to communicate with the ink storage chamber 62a.

[0026] 3 is made of, for example, a flexible resin. The cap 63 can be attached to and detached from the upper end of the cylindrical body 66 by a user operation, and closes or opens the ink inlet 67. The ink inlet 67 is normally closed by the cap 63, and is removed from the cylindrical body 66 and opened when ink is to be injected into the ink storage chamber 62a.

[0027] As shown in FIG. 3(b), the tank body 62 has an atmosphere communication port 62e formed therein that penetrates its rear side wall 62d and connects the ink storage chamber 62a to the outside. The atmosphere communication port 62e is located near the upper end of the rear side wall 62d. As shown in FIG. 3, the tank body 62 also has an upper indicator 62f1 and a lower indicator 62f2 formed in its front side wall 62f. The atmosphere communication port 62e may be located above the upper indicator 62f1, and may be formed in the top wall 62b, for example.

[0028] In FIG. 3, the upper indicator 62f1 has a linear shape extending left and right near the upper end on the outer surface of the front sidewall 62f. The upper indicator 62f1 is located below the air vent 62e in the up-down direction A1, as shown in FIG. 3(b). The upper indicator 62f1 is an example of an indicator that indicates the liquid level of the maximum amount of ink that can be stored in the ink storage chamber 62a. The lower indicator 62f2 has a linear shape extending left and right near the lower end on the outer surface of the front sidewall 62f. The lower indicator 62f2 indicates the liquid level at which ink needs to be refilled, i.e., injected into the ink storage chamber 62a. The upper indicator 62f1 and the lower indicator 62f2 can also be realized by unevenness formed on the outer surface of the front sidewall 62f or by coloring with paint or the like.

[0029] As shown in FIG. 3(b), the electromagnetic valve 64 is a known two-way electromagnetic valve and includes a valve portion 64a and a solenoid portion 64b. The electromagnetic valve 64 is fixed to the upper wall 62b so as to be positioned above the upper indicator 62f1. The valve portion 64a is disposed in the ink storage chamber 62a and includes an internal flow path (not shown) that communicates with the atmosphere communication port 62e and the ink storage chamber 62a, and a valve (not shown) that opens and closes the internal flow path. The solenoid portion 64b is disposed on the upper wall 62b and opens and closes the valve of the valve portion 64a. Under the control of the control unit 5, the solenoid unit 64b of the electromagnetic valve 64 is driven, and the valve unit 64a selectively takes either a communication state in which the atmosphere communication port 62e communicates with the ink storage chamber 62a (i.e., a state in which the valve opens the internal passage), or a blocking state in which the communication between the atmosphere communication port 62e and the ink storage chamber 62a is blocked (i.e., a state in which the valve closes the internal passage).

[0030] As a modified example, the solenoid valve 64 may have the valve portion 64a connected to the outside of the ink tank 61 so as to communicate with the atmosphere communication port 62e. In this case, it is possible to selectively set the atmosphere communication port 62e in a communication state where it is connected to the outside and in a blocked state where it is blocked from communication with the outside. Alternatively, the entire solenoid valve 64 may be disposed in the ink storage chamber 62a. Alternatively, the solenoid valve 64 may be fixed to at least one of the front, rear, left, or right side walls of the tank body 62 other than the top wall 62b, as long as the internal flow path of the valve portion 64a is connected so as to be able to communicate with the atmosphere communication port 62e.

[0031] The tank body 62 also has an outlet 62h formed therein that penetrates its bottom wall 62g and allows ink in the ink storage chamber 62a to flow out to the inkjet head 41. The outlet 62h is located in the center of the bottom wall 62g in the left-right direction A3, near the front end.

[0032] As shown in FIG. 3(b), a protrusion 62i that protrudes rearward is formed on the rear sidewall 62d of the tank body 62. The protrusion 62i is made of a light-transmitting material and has a generally rectangular parallelepiped shape. The protrusion 62i extends in the up-down direction A1 from a position below the lower indicator 62f2 to a position above it. The left-right dimension of the protrusion 62i is smaller than the left-right dimension of the ink storage chamber 62a. The protrusion 62i defines an internal space that communicates with the ink storage chamber 62a.

[0033] <Liquid volume sensor 6> The liquid level sensor 6 is a transmissive optical sensor and includes a light-emitting element and a light-receiving element that receives light from the light-emitting element and is positioned so that the protrusion 62i is sandwiched between the light-emitting element and the light-emitting element. The light-emitting element emits parallel light in the left-right direction A3 toward a portion of the protrusion 62i that is approximately in the same vertical position as the lower index 62f2. The liquid level sensor 6 outputs a signal to the control unit 5 indicating a level corresponding to the amount of light received by the light-receiving element. In other words, the liquid level sensor 6 outputs different signals to the control unit 5 when the ink level in the ink storage chamber 62a is below the lower index 62f2 (i.e., when the ink tank 61 is empty) and when it is not. In this way, the liquid level sensor 6 can detect whether the ink tank 61 is empty by detecting the ink level.

[0034] <Inkjet head 41> Black ink is supplied to the inkjet head 41 from an ink tank 61. The inkjet head 41 ejects ink from a plurality of nozzles 42 formed on a nozzle surface 41a, which is the lower surface of the inkjet head 41. More specifically, the plurality of nozzles 42 form a nozzle row that extends in the front-rear direction A2, which is the transport direction of the paper P. Black ink is ejected from the plurality of nozzles 42. As shown in FIGS. 4 and 5, the inkjet head 41 has a flow path unit 43 and a piezoelectric actuator 50.

[0035] <Flow path unit 43> As shown in Fig. 5, the flow path unit 43 is formed by stacking four plates 43a to 43d in order from top to bottom. A plurality of nozzles 42 are formed in the plate 43d, as shown in Figs. 4 and 5. A plurality of pressure chambers 45 are formed in the plate 43a. A pressure chamber 45 is provided for each nozzle 42, and the right end of each pressure chamber 45 overlaps with the nozzle 42 in the up-down direction A1.

[0036] 4 and 5, the plate 43b has circular through-holes 46a formed in portions overlapping in the up-down direction A1 with the left end of each pressure chamber 45. The plate 43b also has circular through-holes 46b formed in portions overlapping in the up-down direction A1 with the right end of each pressure chamber 45 and the nozzle 10.

[0037] 4 and 5, a manifold flow path 47 is formed in the plate 43c. The manifold flow path 47 extends in the front-rear direction A2 (the conveying direction) and overlaps with left portions of the multiple pressure chambers 45 in the up-down direction A1. This allows each pressure chamber 45 to communicate with the manifold flow path 47 via the through-holes 46a. In addition, as shown in FIG. 4, a supply port 48 is provided at the downstream end of the manifold flow path 47 in the conveying direction.

[0038] 3, the inkjet head 41 is connected to the ink tank 61 via a connection member 69. The connection member 69 has a communication path (liquid flow path) 69a that connects the outlet 62h and the supply port 48. This allows ink in the ink storage chamber 62a of the ink tank 61 to be supplied to the manifold flow path 47 via the supply port 48.

[0039] 4 and 5, the plate 43c has circular through holes 49 formed in portions that overlap with the through holes 46b and the nozzles 42 in the up-down direction A1. This allows the nozzles 42 to communicate with the pressure chambers 45 via the through holes 46b and 49.

[0040] In the flow path unit 43, an individual flow path 44 is formed by the nozzle 42, the pressure chamber 45, through holes 46b and 49 that connect the nozzle 42 and the pressure chamber 45, and the through hole 46a that connects the pressure chamber 45 to the manifold flow path 47. A plurality of individual flow paths 44 are formed corresponding to the plurality of nozzles 42.

[0041] <Piezoelectric actuator 50> 4 and 5, the piezoelectric actuator 50 has a diaphragm 51, a piezoelectric layer 52, a common electrode 53, and a plurality of individual electrodes 54. The diaphragm 51 is made of a piezoelectric material containing lead zirconate titanate as a main component, and is disposed on the upper surface of the flow path unit 43, covering the plurality of pressure chambers 45. Unlike the piezoelectric layer 52, the diaphragm 51 may be made of an insulating material other than a piezoelectric material.

[0042] The piezoelectric layer 52 is made of a piezoelectric material, and as shown in Fig. 4, is disposed on the upper surface of the vibration plate 51 and extends continuously across the plurality of pressure chambers 45. As shown in Fig. 5, the common electrode 53 is disposed between the vibration plate 51 and the piezoelectric layer 52 and extends continuously across the plurality of pressure chambers 45. The common electrode 53 is connected to a power supply circuit (not shown) via wiring members (FPC 92, COF 92) described below and is maintained at ground potential.

[0043] As shown in FIG. 4, the individual electrodes 54 individually correspond to the pressure chambers 45. Each individual electrode 54 has an elliptical planar shape that is slightly smaller than the pressure chambers 45. The individual electrodes 54 are disposed on the upper surface of the piezoelectric layer 52 and overlap the central portions of the pressure chambers 45 in the up-down direction a1. The right end of each individual electrode 54 extends to the right to a position where it does not overlap the pressure chambers 45 in the up-down direction A1, and its tip serves as a connection terminal 54a. A COF 91 (described later) is connected to the connection terminal 54a, and the individual electrodes 54 are connected to a driver IC 59 (see FIG. 7) mounted on the COF (Chip On Film) 91. The driver IC 59 selectively applies either a ground potential or a predetermined drive potential (e.g., approximately 20 V) to each of the individual electrodes 54.

[0044] Furthermore, the portions of the piezoelectric layer 52 sandwiched between the common electrode 53 and each individual electrode 54 are polarized in the vertical direction A1. In the piezoelectric actuator 50 having the above structure, the portions of the vibration plate 51, piezoelectric layer 52, and common electrode 53 that overlap each pressure chamber 45 in the vertical direction, and the portions formed by the individual electrodes 54, each serve as a drive element 55 that applies pressure to the ink in the pressure chamber 45.

[0045] Here, a method for driving the piezoelectric actuator 50 to eject ink from the nozzle 42 will be described. In the piezoelectric actuator 50, all of the individual electrodes 54 are previously held at the same ground potential as the common electrode 53. When ink is to be ejected from a certain nozzle 42, the potential of the individual electrode 54 in the drive element 55 corresponding to that nozzle 42 is switched from the ground potential to the drive potential. Then, due to the potential difference between the individual electrode 54 and the common electrode 53, the portions of the diaphragm 51 and the piezoelectric layer 52 that overlap with the pressure chamber 45 in the up-down direction A1 are deformed so as to become convex toward the pressure chamber 45 as a whole. This reduces the volume of the pressure chamber 45, increasing the pressure of the ink in the pressure chamber 45, and ink is ejected from the nozzle 42 that communicates with the pressure chamber 45.

[0046] <Platen 17> The platen 17 is disposed below the inkjet head 41 and supports the paper P being transported by the transport roller pair 35. The platen 17 is disposed in a portion of the reciprocating movement range of the carriage 70 through which the paper P passes. The width of the platen 17 is sufficiently larger than the maximum width of the paper P that can be transported, so the paper P being transported along the transport path 25 always passes over the platen 17.

[0047] <Movement mechanism 71> As shown in FIG. 2, the movement mechanism 71 includes a pair of guide rails 72 and a belt transmission mechanism (not shown). The pair of guide rails 72 are disposed at a distance from each other in the front-rear direction A2 and extend parallel to each other in the left-right direction A3. The carriage 70 is disposed so as to straddle the pair of guide rails 72. The carriage 70 is connected to a carriage motor 70M (see FIG. 7) via the belt transmission mechanism, and driving the carriage motor 70M drives the belt transmission mechanism. This causes the carriage 70 to move in the scanning direction (left-right direction A3) along the pair of guide rails 72, moving the inkjet head 41 between a maintenance position facing a maintenance cap (not shown) and a non-maintenance position not facing the maintenance cap.

[0048] The inkjet head 41 ejects ink from the nozzles 42 under the control of the control unit 5 based on the recording data. In other words, as the carriage 70 moves back and forth in the left-right direction A3, the inkjet head 41 scans the paper P and ejects ink from the nozzles 42, thereby recording an image on the paper P being transported over the platen 17. The printer 1 is provided with a linear encoder (not shown) having a number of light-transmitting portions (slits) arranged at intervals in the scanning direction. The carriage 70 is also provided with a transmission-type position detection sensor (not shown) having a light-emitting element and a light-receiving element. The printer 1 is able to recognize the current position of the carriage 51 in the scanning direction from the count value of the light-transmitting portions of the linear encoder detected by the position detection sensor while the carriage 70 is moving, and controls the rotational drive of the carriage motor 70M.

[0049] <Relay board 80> As shown in FIG. 6, the relay board 80 is connected to the control board 7 of the control unit 5 via an FPC (Flexible Printed Circuits: flexible flat cable) 8. The relay board 80 is supported by the carriage 70 and, as shown in FIG. 3(b), is disposed behind the ink tanks 61 in a state in which it stands along the up-down direction A1. In other words, the relay board 80 is disposed upstream of the inkjet heads 41 in the transport direction and intersects with the horizontal plane. As shown in FIG. 6, the relay board 80 has a board main body 81 having a rectangular planar shape, four connection portions 82 to 85, a plurality of head wirings 86, a valve wiring 88, and a sensor wiring 89. The four connection portions 82 to 85, the plurality of head wirings 86, the valve wiring 88, and the sensor wiring 89 are formed on the surface of the board main body 81.

[0050] As shown in Fig. 6, the connection portion 82 is formed at the right end of the substrate main body 81, extending in the vertical direction A1. One end of the FPC 8 is connected to the connection portion 82 in a state in which the FPC 8 stands in the vertical direction A1. The connection portion 83 is formed at the center of the lower end of the substrate main body 81, extending in the horizontal direction A3. As shown in Fig. 3(b), the connection portion 83 is connected to an FPC 92 connected to a COF 91 which is connected to the piezoelectric actuator 50 of the inkjet head 41. The COF 91 has the above-mentioned driver IC 59 mounted thereon.

[0051] As shown in Fig. 6, the connection part 84 is disposed near the center of the upper end part of the substrate main body 81. As shown in Fig. 3(b), a wiring 93 connected to the electromagnetic valve 64 is connected to the connection part 84. As shown in Fig. 6, the connection part 85 is disposed in the lower part of the left end part of the substrate main body 81. As shown in Fig. 3(b), a wiring 94 connected to the liquid level sensor 6 is connected to the connection part 85.

[0052] 6, the plurality of head wirings 86 are formed so as to connect the connection portion 82 and the connection portion 83. The valve wiring 88 is formed so as to connect the connection portion 82 and the connection portion 84. The sensor wiring 89 is formed so as to connect the connection portion 82 and the connection portion 85. The plurality of head wirings 86 are arranged below the sensor wiring 89 at the connection portion 82. The valve wiring 88 is arranged above the sensor wiring 89 at the connection portion 82.

[0053] <fpc8> As shown in FIG. 6, one end of the FPC 8 is connected to the connection portion 82, and the other end is connected to the connection portion 7a of the control board 7. The FPC 8 has a plurality of head signal lines 8a, a ground line 8g, a sensor signal line 8c, and a valve signal line 8b. The head signal lines 8a are lines for transmitting signals from the control board 7 to the inkjet head 41. The ground line 8g is a line for maintaining the common electrode 53 of the inkjet head 4 at ground potential. The sensor signal line 8c is a line for transmitting signals from the liquid volume sensor 6 to the control board 7. The valve signal line 8b is a line for transmitting signals from the control board 7 to the electromagnetic valve 64. The head signal lines 8a, the ground line 8g, the sensor signal line 8c, and the valve signal line 8b are arranged in this order from bottom to top. That is, the connection positions of the multiple head signal lines 8a to the relay board 80 are arranged below the connection positions of the sensor signal lines 8c and the valve signal lines 8b to the relay board 80. In addition, the ground line 8g is arranged between the head signal lines 8a and the valve signal lines 8b.

[0054] <Control unit 5> As shown in FIG. 7 , the control unit 5 includes a CPU (Central Processing Unit) 131, an ASIC (Application Specific Integrated Circuit) 135, a memory 140, and a control board 7 on which these components are mounted. The CPU 131, the ASIC 135, and the memory 140 are connected via an internal bus 137. The memory 140 includes a ROM (Read Only Memory) 132, a RAM (Random Access Memory) 133, and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 134. The ROM 132 stores programs for controlling various operations of the printer 1. The CPU 131 executes the programs using the RAM 133 and the EEPROM 134. Note that at least one of the CPU 131 and the memory 140 may not be mounted on the control board 7 and may be provided separately.

[0055] The ASIC 135 outputs control signals to the ASF motor 20M, the LF motor 35M, the carriage motor 70M, the electromagnetic valve 64, the inkjet head 41, etc., and controls their operation. For example, the control unit 5 controls the inkjet head 41, the ASF motor 20M, the LF motor 35M, the carriage motor 70M, etc., based on recording data transmitted from an external device (for example, a PC or a smartphone), to alternately perform a conveying process and a recording process, and record an image, etc., on the paper P. The ASIC 135 also receives a signal from the liquid level sensor 6.

[0056] The conveying process is a process in which the conveying roller pair 35 and the paper discharge roller pair 36 convey the paper P by a predetermined line feed amount. The control unit 5 controls the LF motor 35M to cause the conveying roller pair 35 and the paper discharge roller pair 36 to perform the conveying process. The recording process is a process in which the carriage 70 moves in the left-right direction A3 while controlling the power supply to the drive element 55 to eject ink droplets from the nozzles 42. The control unit 5 then stops the conveyance of the paper P for a certain period between the current conveying process and the next conveying process, and performs the recording process while the conveyance of the paper P is stopped. That is, in the recording process, the control unit 5 performs one pass in which ink droplets are ejected from the nozzles 42 while moving the carriage 70 rightward or leftward. This completes one pass of image recording on the paper P. The control unit 5 alternately performs the conveying process and the recording process to record an image on the entire image-recordable area of ​​the paper P. That is, the control unit 5 records an image on one sheet of paper P in multiple passes.

[0057] In this embodiment, the control unit 5 has one CPU and one ASIC, but the control unit 5 may also include only one ASIC, with this one ASIC performing all the necessary processing at once, or may include multiple ASICs, with these multiple ASICs sharing the necessary processing.

[0058] An ink count value (liquid count value), a reference value, and an ink threshold value (liquid threshold value) are stored in the memory 140. The ink count value is a value that is updated according to the amount of ink ejected from the inkjet head 41, and is stored in the RAM 133 or the EEPROM 134. The ink count value is calculated based on recording data, which is data of an image to be recorded on the paper P.

[0059] More specifically, the control unit 5 references recording data transmitted from an external device (e.g., a PC or smartphone). The recording data is transmitted sequentially from the external device. Based on the recording data, the control unit 5 estimates the amount of ink to be ejected in the next recording process and determines an ink count value corresponding to that amount of ink. In other words, based on the recording data, the control unit 5 determines the number of times ink droplets will be ejected for each dot in the area to be ejected in the next recording process. This allows the number of times that all dots in the area will be ejected to be calculated by adding up the number of times each dot is ejected. The calculated number of times that all dots in the area will be ejected is the ink count value corresponding to the amount of ink to be ejected in the next recording process.

[0060] As will be described later, the ink count value is updated by being accumulated based on the recording data. The ink count value is also reset to an initial value at a predetermined timing (when ink is replenished) under the control of the control unit 5. The initial value is a preset initial value for the ink count value and is stored in the ROM 132 or EEPROM 134. In this embodiment, the initial value is zero. Note that in this embodiment, the ink count value counts up from an initial value of zero, but this is not limited to this. For example, the ink count value may count down from an initial value other than zero.

[0061] The ink threshold is a value compared with the consumption amount of ink stored in the ink storage chamber 62a and is a value used to determine the timing of opening the electromagnetic valve 64. Specifically, the ink threshold is a preset value so that the difference between the ink count value and the reference value reaches the ink threshold before an increase in negative pressure in the ink storage chamber 62a causes damage to the ink meniscus formed in the nozzle 42. The ink threshold is a design value determined for the ink meniscus withstand pressure and indicates a value below the withstand pressure. In other words, when the difference does not reach the ink threshold, the negative pressure in the ink storage chamber 62a is not so high, and the ink meniscus formed in the nozzle 42 will not be damaged. On the other hand, when the difference reaches the ink threshold, the ink meniscus formed in the nozzle 42 is prone to damage due to an increase in negative pressure. The ink threshold is also determined by the ratio of the volume of the ink space to the volume of the air space when the maximum amount of ink is stored in the ink storage chamber 62a. In this embodiment, the ink threshold value is stored in the ROM 132 or the EEPROM 134 .

[0062] Next, the recording operation of the printer 1 will be described below with reference to Figure 8. In the printer 1, the inkjet head 41 is located in the maintenance position when the printer 1 is on standby (when no recording operation is being performed). At this time, the electromagnetic valve 64 is in a blocking state, blocking communication with the atmosphere communication port 62e. This prevents the ink in the ink storage chamber 62a from evaporating.

[0063] A recording command is sent to the control unit 5 from the operation unit 13 of the printer 1 or an external device. The recording command includes a command to start a recording operation, information about the size of the paper P, and recording data to be recorded as an image on the paper P.

[0064] If the control unit 5 has not received a recording command (NO) in S1, it waits by repeating S1, and if the control unit 5 has received a recording command (Yes), it proceeds to S2.

[0065] In S2, the control unit 5 drives the ASF 20M to feed the paper P from the paper feed tray 15. In S2, the control unit 5 also drives the LF motor 35M to transport the paper P and perform cueing when the leading edge of the paper P reaches the pair of transport rollers 35. In cueing, the control unit 5 stops the paper P at the image recording start position. The image recording start position is the position where the leading edge (downstream end) of the image recording area on the paper P in the transport direction faces the nozzle 42 that is arranged furthest downstream in the transport direction among the multiple nozzles 42.

[0066] Furthermore, in S2, the control unit 5 drives the carriage motor 70M to move the carriage 70 (inkjet head 41) from the maintenance position to the start position. The start position is the movement start position of the carriage 70 when the recording process (S7) is executed, and is determined based on the recording data. Note that in S2, the operations from feeding the paper P to locating the beginning and the movement operation of the carriage 70 are executed in parallel.

[0067] Next, in S3, the control unit 5 references the print data and determines an ink count value corresponding to the amount of ink to be ejected in the next pass, i.e., the next printing process (S7).The control unit 5 then adds the determined ink count value to the ink count value currently stored in memory 140, and stores the result of the addition in memory 140 as a new ink count value.This updates the ink count value.

[0068] Next, in S4, the control unit 5 determines whether the difference between the ink count value and the reference value has reached the ink threshold value (determination process). The control unit 5 stores the reference value in memory 140 as the ink count value stored in memory 140 during the previous shutoff process, when the solenoid valve 64 transitioned from the open state to the shutoff state. As the recording process of S7, described below, is repeatedly executed and the ink count value is updated, the difference between the ink count value and the reference value may reach the ink threshold value. If this is the case (YES), the process proceeds to S5. On the other hand, if the difference has not reached the ink threshold value (NO), the process proceeds to S7.

[0069] Next, the control unit 5 executes a communication process in S5. That is, the control unit 5 drives the electromagnetic valve 64 to change from a blocked state to a connected state. This causes the atmosphere communication port 62e to communicate, and the ink storage chamber 62a becomes open to the atmosphere. Therefore, the negative pressure in the ink storage chamber 62a decreases (the pressure becomes equilibrium with atmospheric pressure). As a result, damage to the ink meniscus formed in the nozzle 42 is suppressed, and it is possible to suppress air from entering the nozzle 42 and ink from leaking from the nozzle 42.

[0070] Next, the control unit 5 executes a shutoff process in S6. That is, the control unit 5 drives the electromagnetic valve 64 to change from a connected state to a shutoff state. This shuts off communication through the atmosphere communication port 62e, closing the ink storage chamber 62a to the atmosphere. At this time, the control unit 5 stores the ink count value currently stored in the memory 140 in the memory 140 as a reference value (storage process).

[0071] Next, the control unit 5 executes the recording process in S7. That is, the control unit 5 executes one pass in which ink droplets are ejected from the nozzles 42 while moving the carriage 70 from the start position.

[0072] Next, in S8, the control unit 5 determines whether image recording on the paper P is complete based on the information about the size of the paper P and the recording data included in the recording command. If image recording on the paper P is not complete (NO), the process proceeds to S9, where a conveying process is performed. If image recording on the paper P is complete (YES), the process proceeds to S10.

[0073] Next, in S9, the control unit 5 drives the LF motor 35M to cause the pair of conveying rollers 35 and the pair of paper discharge rollers 36 to convey the paper P by a predetermined line feed amount. After this, the process returns to S3, and the control unit 5 determines an ink count value corresponding to the amount of ink to be ejected in the next recording process (S7), and adds the determined ink count value to the ink count value up to that point. Thereafter, the processes of steps S4 to S8 are executed again. Note that the update of the ink count value in S3 may be executed in parallel with the conveying process.

[0074] Next, in S10, the control unit 5 drives the LF motor 35M to cause the pair of conveying rollers 35 and the pair of paper discharge rollers 36 to convey the paper P and discharge it onto the paper discharge tray 16.

[0075] Next, in S11, the control unit 5 determines whether or not the image data included in the recording command contains image data that has not been recorded on the paper P, i.e., whether or not there is image recording for the next page. If there is image recording for the next page (YES), the process returns to S2. On the other hand, if there is no image recording for the next page (NO), the control unit 5 ends the series of recording operations.

[0076] Next, the operation of the printer 1 when the liquid level sensor 6 detects that the ink tank is empty will be described below with reference to Figure 9. In the printer 1, the amount of ink in the ink tank 61 decreases as ink evaporates or ink is discharged from the nozzles 42 during printing operations. At this time, the electromagnetic valve 64 assumes a blocked state in which communication with the atmosphere communication port 62e is blocked.

[0077] In S101, the control unit 5 determines whether or not a signal indicating that the ink level is empty has been output from the liquid level sensor 6. If a signal indicating that the ink level is empty has not been output (NO), S101 is repeatedly executed. On the other hand, if the ink level in the ink storage chamber 62a has fallen below the lower indicator 62f2 due to ink evaporation or ink discharge from the nozzles 42, and a signal indicating that the ink level is empty has been output from the liquid level sensor 6 (YES), the process proceeds to S102.

[0078] In S102, the control unit 5 executes a notification process. That is, the control unit 5 displays a message on the liquid crystal display of the operation unit 13 indicating that the ink in the ink tank 61 is empty, thereby notifying the user.

[0079] Next, the control unit 5 executes a communication process in S103. That is, the control unit 5 drives the electromagnetic valve 64 to establish a communication state, as in S5 described above. This establishes communication through the atmosphere communication port 62e, opening the ink storage chamber 62a to the atmosphere. After this, the user opens the access cover 14 of the housing 11, removes the cap 63, and opens the ink inlet 67. Then, an ink bottle (not shown) is inserted into the ink inlet 67 to inject black ink into the ink storage chamber 62a. At this time, the electromagnetic valve 64 is in a communication state, opening the ink storage chamber 62a to the atmosphere, preventing the internal pressure of the ink storage chamber 62a from increasing during ink injection. This prevents damage to the ink meniscus formed in the nozzle 42 and reduces the likelihood of ink leakage from the nozzle 42.

[0080] Next, in S104, the control unit 5 determines whether a signal indicating that the ink level is empty has been output from the liquid level sensor 6. If a signal indicating that the ink level is empty has been output (YES), the control unit 5 waits and repeats S104. On the other hand, if the ink filling into the ink tank 61 has been completed and a signal indicating that the ink level is empty has not been output from the liquid level sensor 6 (NO), the control unit 5 proceeds to S105.

[0081] Next, in S105, the control unit 5 executes the cutoff process. That is, similar to S6 described above, the control unit 5 drives the electromagnetic valve 64 to change from the connected state to the cutoff state. At this time, the control unit 5 resets the ink count value currently stored in the memory 140 to the initial value, and stores this ink count value in the memory 140 as a reference value (storage process). This ends the flow.

[0082] As described above, in the printer 1 of this embodiment, the connection positions of the multiple head signal wires 8a of the FPC 8 to the relay substrate 80 are positioned lower than the connection positions of the sensor signal wires 8c and the valve signal wires 8b to the relay substrate 80. Therefore, the connection position of the valve signal wire 8b to the relay substrate 80 is closer to the electromagnetic valve 64, and the connection position of the head signal wire 8a to the relay substrate 80 is closer to the inkjet head 41. Therefore, it is not necessary to cross the valve wiring 88 connected to the valve signal wire 8b and the head wiring 86 connected to the head signal wire 8a within the relay substrate 80, thereby suppressing noise interference. Furthermore, it is possible to suppress the length of the wiring members (COF 91 and FPC 92) connecting from the relay substrate 80 to the piezoelectric actuator 50 of the inkjet head 41 and the wiring 93 connecting from the relay substrate 80 to the electromagnetic valve 64.

[0083] Furthermore, since the relay substrate 80 is installed standing upright in the up-down direction A1, the connection position of the valve signal wire 8b to the relay substrate 80 is closer to the electromagnetic valve 64, and the connection position of the head signal wire 8a to the relay substrate 80 is closer to the inkjet head 41. This makes it possible to further prevent the wiring members (COF 91 and FPC 92) and the wiring 93 from becoming longer.

[0084] In addition, the relay substrate 80 is disposed upstream in the transport direction from the inkjet head 41. The electromagnetic valve 64 is disposed upstream in the transport direction from the inkjet head 41. This makes it possible to prevent the wiring 93 from becoming too long.

[0085] When it is determined in S4 that the difference has reached the ink threshold value, the control unit 5 executes a communication process in S5, thereby making it possible to prevent damage to the ink meniscus formed in the nozzle 42.

[0086] In the above-described embodiment, whether the negative pressure in the ink storage chamber 62a is within the allowable range is determined by whether the difference between the ink count value and the reference value reaches the ink threshold value. However, as shown by the two-dot chain line in FIG. 3B, a pressure sensor 400 may be provided in the ink tank 61, which detects the pressure in the ink storage chamber 62a and outputs a signal corresponding to the pressure to the control unit 5. In this modification, instead of the determination process of S4, the control unit 5 executes a determination process to determine whether the pressure detected by the pressure sensor 400 reaches a predetermined value. Note that the predetermined value may be a value less than the withstand pressure of the ink meniscus formed in the nozzle 42. If the determination process determines that the pressure has reached the predetermined value, a communication process similar to S5 is executed, followed by a blocking process similar to S6. In this modification, as in the above-described embodiment, damage to the ink meniscus in the nozzle 42 can be prevented. Furthermore, since the pressure in the ink storage chamber 62a is detected by the pressure sensor 400, the pressure can be detected with high accuracy.

[0087] As another modification, the pressure in the ink storage chamber 62a may be detected using a sensor other than a pressure sensor, such as at least one of a liquid volume increase / decrease sensor that detects an increase or decrease in the liquid volume in the ink storage chamber 62a, a temperature sensor, and a humidity sensor. The liquid volume increase / decrease sensor may detect the pressure in the ink storage chamber 62a by detecting a predetermined increase or decrease in the ink volume. Alternatively, a temperature sensor or humidity sensor may be used to detect the pressure in the ink storage chamber 62a based on changes in the ambient temperature or humidity. A combination of these sensors may also be used to accurately detect the pressure in the ink storage chamber 62a. By performing the same process as when using the pressure sensor 400 described above, the same effect as in the modification described above can be achieved.

[0088] Since the inkjet head 41 and the ink tank 61 are supported by the carriage 70, the printer 1 is an on-carriage type.

[0089] Since the electromagnetic valve 64 is a valve that selectively switches between a communication state that connects the atmosphere communication port 62e and a blocking state that blocks communication, the manufacturing cost of the printer 1 is relatively low. Alternatively, the valve may be an electric ball valve or an electric butterfly valve, as long as it can be driven electrically.

[0090] The head signal line 8a and the valve signal line 8b constitute multiple wirings formed on one FPC 8. As a result, the head signal line 8a and the valve signal line 8b are formed on one FPC 8, which makes it easier to arrange these signal lines 8a, 8b than if the head signal line 8a and the valve signal line 8b were formed as separate wiring members, and also makes it possible to prevent the head signal line 8a and the valve signal line 8b from crossing each other.

[0091] A ground line 8g is arranged between the head signal line 8a and the valve signal line 8b on the FPC 8. This makes the separation distance between the head signal line 8a and the valve signal line 8b relatively large, making it possible to suppress crosstalk.

[0092] The ink tank 61 has an ink inlet 67, which allows ink to be injected into the ink storage chamber 62a.

[0093] As a first modified example, as shown in FIG. 10 , the relay board 280 may be installed horizontally. Note that components similar to those in the above-described embodiment are designated by the same reference numerals and will not be described again. The relay board 280 in this modified example is also connected to the control board 7 of the control unit 5 via an FPC 8. The relay board 280 is also installed above the ink tank 61. In other words, the relay board 280 is installed so as to intersect with a vertical plane facing the transport direction (front-rear direction A2). The relay board 280 has a board main body 281 having a rectangular planar shape, four connection portions 282 to 285, a plurality of head wirings 286, a valve wiring 288, and a sensor wiring 289. These four connection portions 282 to 285, the plurality of head wirings 286, the valve wiring 288, and the sensor wiring 289 are formed on the surface of the board main body 281.

[0094] 10(b), the connection portion 282 is formed at the right end of the substrate main body 281, extending in the front-rear direction A2. One end of an FPC 8 arranged along a horizontal plane is connected to the connection portion 282. The connection portion 283 is formed at the left end of the substrate main body 281, extending in the front-rear direction A2. The connection portion 283 is connected to an FPC 92 connected to a COF 91 connected to a piezoelectric actuator 50 of the inkjet head 41.

[0095] 10, the connection part 284 is disposed near the center of the rear end part of the substrate main body 281. A wiring 93 connected to the electromagnetic valve 64 is connected to the connection part 284. The connection part 285 is disposed near the rear end part of the substrate main body 281, between the connection parts 283 and 284 in the left-right direction A3. The wiring 94 connected to the liquid level sensor 6 is connected to the connection part 285.

[0096] 10(b), the plurality of head wirings 286 are formed to extend in the left-right direction A3 so as to connect the connection portion 282 and the connection portion 283. The valve wiring 288 is formed so as to connect the connection portion 282 and the connection portion 284. The sensor wiring 289 is formed so as to connect the connection portion 282 and the connection portion 285. The plurality of head wirings 286 are arranged in front of the sensor wiring 289 (downstream in the transport direction) at the connection portion 282. The valve wiring 288 is arranged in the rear of the sensor wiring 289 (upstream in the transport direction) at the connection portion 282.

[0097] With this relay substrate 280, the connection positions of the multiple head signal wires 8a of the FPC 8 to the relay substrate 280 are disposed forward (downstream in the transport direction) of the connection positions of the sensor signal wires 8c and the valve signal wires 8b to the relay substrate 280. The electromagnetic valve 64 is disposed behind the inkjet head 41, i.e., upstream in the transport direction. Therefore, in the transport direction, the connection position of the valve signal wire 8b to the relay substrate 280 is closer to the electromagnetic valve 64, and the connection position of the head signal wire 8a to the relay substrate 280 is closer to the inkjet head 41. Therefore, it is no longer necessary to cross the valve wiring 288 connected to the valve signal wire 8b and the head wiring 286 connected to the head signal wire 8a within the relay substrate 280, making it possible to suppress noise interference. It is also possible to prevent the wiring members (COF 91 and FPC 92) connecting from the relay substrate 280 to the piezoelectric actuator 50 of the inkjet head 41, and the wiring 93 connecting from the relay substrate 280 to the electromagnetic valve 64, from becoming longer.

[0098] Furthermore, since the relay substrate 280 is installed horizontally (in the front-to-back direction A2 and the left-to-right direction A3), the connection position of the valve signal wire 8b to the relay substrate 280 is closer to the electromagnetic valve 64, and the connection position of the head signal wire 8a to the relay substrate 280 is closer to the inkjet head 41. This makes it possible to further prevent the wiring members (COF 91 and FPC 92) and the wiring 93 from becoming longer.

[0099] 11, an atmosphere communication port may be formed in the front side wall 62f, and an electromagnetic valve 64 that can selectively place the atmosphere communication port in a connected state or a disconnected state may be disposed downstream of the inkjet head 41 in the transport direction. Note that components similar to those in the above-described embodiment and modifications are denoted by the same reference numerals and descriptions thereof will be omitted. Also, in this modification, the liquid volume sensor 6 and related components are omitted.

[0100] In this modified example, as shown in FIG. 11 , the relay board 380 is installed horizontally and is connected to the control board 7 of the control unit 5 via an FPC 8. The relay board 380 is also arranged above the ink tanks 61. In other words, the relay board 380 is installed so as to intersect with a vertical plane facing the transport direction (front-rear direction A2). The relay board 380 has a board main body 381 having a rectangular planar shape, three connection parts 382 to 384, a plurality of head wirings 386, and a valve wiring 388. The three connection parts 382 to 384, the plurality of head wirings 386, and the valve wiring 388 are formed on the surface of the board main body 381.

[0101] 11(b), the connection portion 382 is formed at the right end of the substrate main body 381 and extends in the front-rear direction A2. One end of an FPC 8 arranged along a horizontal plane is connected to the connection portion 382. The connection portion 383 is formed at the left end of the substrate main body 381 and extends in the front-rear direction A2. The FPC 92 is connected to a COF 91 which is connected to the piezoelectric actuator 50 of the inkjet head 41.

[0102] 11, the connection part 384 is disposed near the center of the front end part of the substrate main body 381. To the connection part 384, a wire 93 connected to the electromagnetic valve 64 is connected.

[0103] 11(b), the plurality of head wirings 386 are formed to extend in the left-right direction A3 so as to connect the connection portion 382 and the connection portion 383. The valve wirings 388 are formed so as to connect the connection portion 382 and the connection portion 384. The plurality of head wirings 386 are arranged at the connection portion 382 behind the valve wirings 388 (upstream in the transport direction).

[0104] With this relay substrate 380, the connection positions of the multiple head signal wires 8a of the FPC 8 to the relay substrate 280 are located behind (upstream in the transport direction) the connection positions of the valve signal wires 8b to the relay substrate 280. The electromagnetic valve 64 is located ahead of the inkjet head 41, i.e., downstream in the transport direction. Therefore, in the transport direction, the connection positions of the valve signal wires 8b to the relay substrate 380 are closer to the electromagnetic valve 64, and the connection positions of the head signal wires 8a to the relay substrate 380 are closer to the inkjet head 41. This eliminates the need to cross the valve wiring 388 connected to the valve signal wire 8b and the head wiring 386 connected to the head signal wire 8a within the relay substrate 380, thereby suppressing noise interference. Furthermore, it is possible to prevent the wiring members (COF 91 and FPC 92) connecting from the relay substrate 380 to the piezoelectric actuator 50 of the inkjet head 41 and the wiring 93 connecting from the relay substrate 380 to the electromagnetic valve 64 from becoming too long.

[0105] While preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and various modifications are possible within the scope of the claims. In the above-described embodiment, the relay board 80 is installed vertically along the up-down direction A1, but it does not have to be installed vertically as long as it intersects with a horizontal plane. Furthermore, the relay board 80 may be located at a position other than behind the ink tank 61. In the first and second modified examples described above, the relay boards 280 and 380 are installed horizontally, but it does not have to be installed horizontally as long as it intersects with a vertical plane facing the transport direction. Furthermore, the relay boards 280 and 380 may be located at a position other than above the ink tank 61.

[0106] In the above-described embodiment and the first and second modifications, the head signal line 8a and the valve signal line 8b constitute multiple wirings formed on one FPC 8, but the head signal line 8a and the valve signal line 8b may be formed from separate wiring members. Even in this case, the same effects as those described above can be obtained. Furthermore, the ground line 8g does not have to be disposed between the head signal line 8a and the valve signal line 8b on the FPC 8.

[0107] Although the above-described embodiment and the first and second modifications are employed in a monochrome printer, they may also be employed in a color printer. The same effects as those described above can be obtained in this case as well. The ink tank 61 may also have a communication passage connecting the atmosphere communication port 62e and the ink storage chamber 62a. In this case, the electromagnetic valve 64 only needs to be able to selectively place the atmosphere communication passage, which is made up of the communication passage and the atmosphere communication port 62e, in a connected state that communicates with the outside and a blocked state that blocks communication with the outside. The ink tank 61 may also not be provided with an ink inlet 67.

[0108] In the above-described embodiment and the first and second modifications, the ink tank 61 and the inkjet head 41 are of an on-carriage type, in which the ink tank 61 and the inkjet head 41 are mounted on the carriage 70, but the present invention can also be applied to a line-type inkjet head in which the inkjet head is fixed without the carriage 70. In this case as well, the same effects as those described above can be obtained.

[0109] The present invention can also be applied to a liquid ejection device having a liquid ejection head that ejects liquid other than ink. Furthermore, it is also possible to employ an ejection energy applying means other than the piezoelectric actuator 50, as long as it is possible to eject liquid from the nozzles by being driven based on a signal from the control unit 5. In this case, for example, a thermal type ejection energy applying means may be employed, in which a heat generating element heats the liquid ink in the nozzles, generating bubbles that push the ink out of the nozzles for recording. [Explanation of symbols]

[0110] 1. Printer (liquid ejection device) 5. Control section 7 Control board 8 FPC 8a Head signal line 8b Valve signal line 8g ground wire 20 Feeding section (transport mechanism) 35 conveying roller pair (conveying mechanism) 36 Paper ejection roller pair (transport mechanism) 41 Inkjet head (liquid ejection head) 42 nozzles 61 Ink tank (liquid storage unit) 62a Ink storage chamber (liquid storage chamber) 62e Atmospheric vent (atmospheric passage) 64 Solenoid valve (valve) 67 Ink inlet (liquid inlet) 69a Communication passage (liquid flow passage) 70 Carriage 71 Moving mechanism 80,280,380 Relay board 140 memory 400 Pressure sensor (detection means)

Claims

1. a conveying mechanism that conveys the recording medium in a conveying direction; a liquid ejection head having nozzles for ejecting liquid; a liquid storage section including a liquid storage chamber for storing liquid, an atmosphere communication passage for communicating the liquid storage chamber with the outside, and an electrically operated valve capable of selectively setting the atmosphere communication passage in either a communication state or a blocking state; a liquid flow path that connects the liquid ejection head and the liquid storage chamber so that liquid can flow therethrough; a control unit having a control board and controlling the liquid ejection head, the valve, and the transport mechanism; a relay board disposed so as to intersect with a vertical plane facing the conveyance direction; a head signal line connected to connect the control board and the relay board, for transmitting a signal from the control board to the liquid ejection head; a valve signal line connected to connect the control board and the relay board and for transmitting a signal from the control board to the valve, the valve is disposed on one side of the liquid ejection head in the transport direction, The liquid ejection device according to claim 1, wherein the connection position of the valve signal wires to the relay board is on one side in the transport direction with respect to the connection position of the head signal wires to the relay board.

2. 2. The liquid ejection device according to claim 1, wherein the relay substrate is installed along a horizontal direction.

3. 3. The liquid ejection apparatus according to claim 1, wherein the one of the transport directions is an upstream side of the transport direction.

4. 3. The liquid ejection apparatus according to claim 1, wherein the one of the transport directions is downstream in the transport direction.

5. The control unit a memory that stores a liquid count value, a reference value, and a liquid threshold value that indicates a liquid that is less than the withstand pressure value of a liquid meniscus formed in the nozzle, the liquid count value being updated in accordance with the amount of liquid ejected from the nozzle; a storage process for storing the liquid count value when the valve changes from the communicating state to the blocking state in the memory as the reference value; a determination process for determining whether or not the difference between the liquid count value and the reference value reaches the liquid threshold value; a communication process for controlling the valve so that the valve is in the communication state when it is determined in the determination process that the difference has reached the liquid threshold value; 5. The liquid ejection device according to claim 1, further comprising a shutoff process for controlling the valve so that the valve is in the shutoff state after the communication process.

6. The liquid storage device further includes a detection means for detecting the pressure in the liquid storage chamber, The control unit a determination process for determining whether or not the pressure detected by the detection means reaches a predetermined value that is less than the withstand pressure value of the liquid meniscus formed in the nozzle; a communication process for controlling the valve so that the valve is in the communication state when it is determined in the determination process that the pressure has reached the predetermined value; 5. The liquid ejection device according to claim 1, further comprising a shutoff process for controlling the valve so that the valve is in the shutoff state after the communication process.

7. 7. The liquid ejection apparatus according to claim 6, wherein the detecting means is a pressure sensor.

8. a conveying mechanism that conveys the recording medium in a conveying direction; a carriage that supports the liquid ejection head and the liquid storage unit; 8. The liquid ejection device according to claim 1, further comprising a movement mechanism that moves the carriage in a scanning direction that intersects with the transport direction.

9. 9. The liquid ejection device according to claim 1, wherein the valve is an electromagnetic valve.

10. A liquid ejection device according to any one of claims 1 to 9, characterized in that the head signal line and the valve signal line constitute a plurality of wirings formed on a single flexible flat cable.

11. 11. The liquid ejection device according to claim 10, wherein the flexible flat cable has a ground line that is grounded to the ground and is disposed between the head signal line and the valve signal line.

12. 12. The liquid ejection device according to claim 1, wherein the liquid storage section further comprises a liquid inlet that connects the liquid storage chamber to the outside.

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