Liquid discharge device

Abstract

To provide a liquid discharge device, which can suppress air bubble from remaining in a manifold, communicated with a plurality of nozzles arranged along a nozzle arranging direction, whose both end parts are connected to an ink supply hole.SOLUTION: A recording head 30 is provided with: a manifold 103 communicated with a plurality of nozzles opening on a nozzle surface 41; a first air trap chamber 101 communicated with a first end part 103a of the manifold 103 and extended upward from the first end part 103a; a second air trap chamber 102 communicated with a second end part 103b of the manifold 103 and extended upward from the second end part 103b; and a supply flow passage 100 through which the first air trap chamber 101 is communicated with the second air trap chamber 102, which performs purge suction operation by making a cam mechanism selectively open and close a first opening 101a of a first flow passage 100a leading to the first air trap chamber 101 in the supply flow passage 100 and a second opening 105 of a second flow passage 100b leading to the second air trap chamber 102 in the supply flow passage 100.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present disclosure relates to a liquid ejection device. [Background technology]

[0002] Some liquid ejection devices include a nozzle group consisting of a plurality of nozzles arranged in a nozzle arrangement direction, and a manifold extending in the nozzle arrangement direction and communicating with the nozzle group. Both ends of the manifold are connected to ink supply holes. Ink is supplied to the manifold via two ink supply holes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-134880 Summary of the Invention [Problem to be solved by the invention]

[0004] Purging is sometimes performed by creating negative pressure inside the cap that covers the nozzles, forcing ink out of the nozzles. During purging, ink flows from both ends of the manifold toward the center of the manifold. Purging also expels air bubbles present in the manifold from the nozzles along with the ink.

[0005] However, the ink flow from both sides meets in the center of the manifold, and the ink flow speed slows down at this point. When the ink flow speed slows down, air bubbles adhering to the inner wall of the manifold do not separate from the wall, and there is a risk that the air bubbles will not be expelled from the manifold even when purging is performed.

[0006] The present disclosure aims to prevent air bubbles from remaining in a manifold in a liquid ejection device, the manifold communicating with a plurality of nozzles arranged along a nozzle arrangement direction and having both ends connected to ink supply holes. [Means for solving the problem]

[0007] (1) A liquid ejection device according to the present disclosure is a liquid ejection device having a head, a first valve, a second valve, and a cam mechanism, wherein the head includes a plurality of nozzles opening on a nozzle surface, a manifold communicating with the plurality of nozzles, a first air trap chamber communicating with a first end of the manifold and extending upward from the first end, a second air trap chamber communicating with a second end of the manifold and extending upward from the second end, and a valve communicating with the first air trap chamber and the second air trap chamber. the first valve opens and closes a first flow path in the supply flow path that leads to the first air trap chamber, the second valve opens and closes a second flow path in the supply flow path that leads to the second air trap chamber, and the cam mechanism selectively switches between a first state in which the first valve closes the first flow path and the second valve opens the second flow path, and a second state in which the first valve opens the first flow path and the second valve closes the second flow path.

[0008] According to the above configuration, the cam mechanism can selectively switch the first valve and the second valve between the first state and the second state. Purging is performed in the first state or the second state, thereby preventing liquids flowing in opposite directions from merging in the manifold.

[0009] (2) The first flow path may include a first opening at an upper end of the first air trap chamber, and the first valve may open and close the first opening. The second flow path may include a second opening located between the upper end of the first air trap chamber and the upper end of the second air trap chamber, and the second valve may open and close the second opening.

[0010] (3) The first volume of the first air trap chamber and the second volume of the second air trap chamber may be approximately the same.

[0011] (4) The head may further include an exhaust port and an exhaust flow path that connects the upper end of the second air trap chamber with the exhaust port, the supply flow path having a supply hole through which liquid is supplied, the first air trap chamber being located upstream of the second air trap chamber in the flow direction of liquid in the supply flow path, and the supply flow path being connected to the exhaust flow path.

[0012] (5) The cam mechanism includes a motor, a rotating cam, and a transmission mechanism that transmits the driving force of the motor to the rotating cam, and the transmission mechanism may have a reduction gear.

[0013] (6) The pump mechanism may further be provided which is driven by the forward rotation of the motor, and the transmission mechanism may further have a switching mechanism which does not transmit the forward rotation of the motor to the rotating cam, but transmits the reverse rotation of the motor to the rotating cam.

[0014] (7) The pump mechanism may be a tube pump, and may generate suction pressure by rotating the motor forward, and open the inside of the tube to the atmosphere by rotating the motor backward.

[0015] (8) The switching mechanism may be a planetary gear that moves in contact with and out of contact with a gear that drives the rotating cam.

[0016] (9) The planetary gear may be moved in a direction to mesh with the gear by reverse rotation of the motor, and may mesh with the gear after the pump mechanism has opened the inside of the tube to the atmosphere.

[0017] (10) The device may further include a carriage that carries the head, the first valve, the second valve, and the cam mechanism and moves, wherein the cam mechanism is a slide cam, and the slide cam slides to any of the first state, the second state, and a third state in which the first valve opens the first flow path and the second valve opens the second flow path by abutting against a wall as the carriage moves. [Effects of the Invention]

[0018] According to the present disclosure, in a liquid ejection device, air bubbles are prevented from remaining in a manifold that communicates with a plurality of nozzles arranged along the nozzle arrangement direction and has both ends connected to ink supply holes. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of the appearance of a multifunction peripheral 10. As shown in FIG. [Figure 2] FIG. 2 is a schematic diagram showing the main configuration of the printer unit 11. As shown in FIG. [Figure 3] FIG. 3 is a top view showing the arrangement of the carriage 31, the guide rails 35 and 36, and the maintenance unit 50. As shown in FIG. [Figure 4] FIG. 4 is a plan view showing the arrangement of nozzles 40 formed on a nozzle surface 41 of the recording head 30. As shown in FIG. [Figure 5] Figure 5(A) shows a cross section of the maintenance unit 50 in which the cap 43 is positioned away from the recording head 30, and Figure 5(B) shows the same cross section in which the cap 43 is positioned in close contact with the nozzle surface of the recording head 30. [Figure 6] FIG. 6 is a block diagram showing a control system of the printer unit 11 by the control unit 23. [Figure 7] FIG. 7 is a top view showing the flow of ink and air in the flow passage on the BE side of the print head 30 during the exhaust operation. [Figure 8] FIG. 8 shows a vertical cross section of the recording head 30 taken along the line AA in FIG. [Figure 9] FIG. 9 is a perspective view showing an example of the appearance of a recording head 30 in which eight solenoid valves are mounted in series. [Figure 10] FIG. 10 is a perspective view of the recording head 30 equipped with the rotary cam mechanism 130, seen from the rear. [Figure 11] FIG. 11 is a perspective view showing the appearance of the recording head 30 with the valve holder 133 removed. [Figure 12] FIG. 12 is a perspective view of the recording head 30 equipped with the rotary cam mechanism 130, as viewed from the front. [Figure 13] FIG. 13(A) is an external perspective view of the rotating cam 134, and FIG. 13(B) is an axial plan view showing the first cam portion 134a and the second cam portion 134b. [Figure 14] FIG. 14 is a top view showing the section lines EE and FF of the rotating cam mechanism 130 corresponding to the cross-sectional views of FIGS. [Figure 15] Figure 15(A) shows a vertical cross section of the recording head 30 at section line EE in Figure 14 with the rotating cam 134 facing upward in the first direction Da, and Figure 15(B) shows a vertical cross section of the recording head 30 at section line FF in Figure 14. [Figure 16] Figure 16(A) shows a vertical cross section of the recording head 30 at section line EE in Figure 14, with the rotating cam 134 facing upward in the second direction Db, and Figure 16(B) shows a vertical cross section of the recording head 30 at section line FF in Figure 14. [Figure 17] Figure 17(A) shows a vertical cross section of the recording head 30 at section line EE in Figure 14, with the rotating cam 134 facing upward in the third direction Dc, and Figure 17(B) shows a vertical cross section of the recording head 30 at section line FF in Figure 14. [Figure 18] FIG. 18 is a front view illustrating the operation of the transmission cutoff mechanism 140 during purge suction. [Figure 19] FIG. 19 is a front view illustrating the operation of the transmission cutoff mechanism 140 when the pump is opened to the atmosphere. [Figure 20] FIG. 20 is a front view illustrating the operation of the transmission blocking mechanism 140 when the valve is switched. [Figure 21] FIG. 21 is a perspective view showing a configuration for transmitting a rotational driving force from the conveying motor 29 to the rotating cam 134. As shown in FIG. [Figure 22] FIG. 22(A) is a schematic diagram showing the first switching mechanism that transmits the rotational driving force from the conveying motor 29 to the pump mechanism 51, and FIG. 22(B) is a schematic diagram showing the first switching mechanism during image recording. [Figure 23]FIG. 23 is a cross-sectional view taken along the line GG in FIG. 7, showing the state in which air trapped in the first air trap chamber 101 and the second air trap chamber 102 is exhausted. [Figure 24] FIG. 24 is a perspective view showing the appearance of the recording head 30 equipped with the linear cam mechanism 120. As shown in FIG. [Figure 25] FIG. 25 is a perspective view of the appearance of the linear cam 124. As shown in FIG. [Figure 26] 26A is a top view of the recording head 30 in the second state, and FIG. 26B shows a vertical cross section of the recording head 30 taken along the cutting line BB in FIG. 20A. [Figure 27] 27(A) is a top view of the recording head 30 in the first state, and FIG. 27(B) shows a vertical cross section of the recording head 30 taken along the cutting line CC in FIG. 27(A). [Figure 28] FIG. 28(A) is a top view of the recording head 30 in the third state, and FIG. 28(B) shows a vertical cross section of the recording head 30 taken along the cutting line DD in FIG. 14(A). [Figure 29] FIG. 29 shows the flow path on the BE side of the recording head 30 in the first state. [Figure 30] FIG. 30 is an external perspective view showing the right end protrusion 36a and the left end protrusion 36b of the guide rail 36. As shown in FIG. [Figure 31] 31(A) is a top view of the carriage 31 at a position a distance D1 from the right end of the reciprocating movement range, and FIG. 31(B) is a perspective view of the same showing the linear cam 124. FIG. [Figure 32] 32(A) is a top view of the carriage 31 at a position a distance D2 from the right end of the reciprocating movement range, and FIG. 32(B) is a perspective view of the same showing the linear cam 124. FIG. [Figure 33] 33(A) is a top view of the carriage 31 at the right end of the reciprocating movement range, and FIG. 33(B) is a perspective view of the same showing the linear cam 124. FIG. [Figure 34] 34(A) is a top view of the carriage 31 at a position a distance D3 from the left end of the reciprocating movement range, and FIG. 34(B) is a perspective view of the same showing the linear cam 124. FIG. [Figure 35]35A is a top view of the carriage 31 at a position a distance D4 from the left end of the reciprocating movement range, and FIG. 35B is a perspective view of the same showing the linear cam 124. FIG. [Figure 36] 36(A) is a top view of the carriage 31 at the left end of the reciprocating movement range, and FIG. 36(B) is a perspective view of the same showing the linear cam 124. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] An embodiment of a liquid ejection device according to the present disclosure will be described in detail below. Note that the following embodiment is merely an example of the present disclosure, and it goes without saying that the embodiment can be modified as appropriate without departing from the gist of the present disclosure. Furthermore, the up-down direction is defined based on a state in which a multifunction peripheral 10 according to an embodiment of a liquid ejection device according to the present disclosure is installed so that it can be used. The front side is defined as the side on which the operation panel 5 is provided. The left-right direction is defined when the image reading device 1 is viewed from the front side. The front side is also referred to as the front side, and the rear side is also referred to as the rear side.

[0021] [Configuration of multifunction device 10] The multifunction device 10 according to this embodiment has various functions such as a facsimile function, a printer function, and a copy function. As shown in Fig. 1, the multifunction device 10 includes a printer unit 11 and a casing 14. The casing 14 has an opening 13 on the front side.

[0022] [Configuration of Printer Unit 11] The printer unit 11 is an inkjet printer. A paper feed tray 16 is inserted into and removed from the printer unit 11 through an opening 13 (FIG. 2). The paper feed tray 16 stores various types of recording paper 21. The printer unit 11 includes a paper feed unit 15, a paper discharge tray 17, a curved path 20, a recording unit 24, a paper discharge path 37, a first conveyor roller 45, a pinch roller 46, a second conveyor roller 47, and a spur roller 48.

[0023] The paper feed unit 15 feeds recording paper 21 from the paper feed tray 16. The paper feed unit 15 includes a paper feed roller 25, a paper feed arm 26, a paper feed drive transmission mechanism 27, and a paper feed shaft 28. The paper feed roller 25 is rotatably supported at the tip of the paper feed arm 26. The paper feed arm 26 rotates around the paper feed shaft 28 as a rotation axis, and presses the paper feed roller 25 against the upper surface of the recording paper 21 stored in the paper feed tray 16. The rotational drive force of a transport motor 29, which will be described later, is transmitted to the paper feed roller 25 via the drive transmission mechanism 33 and the paper feed drive transmission mechanism 27. When the paper feed roller 25 is driven to rotate, the recording paper 21 is fed.

[0024] The curved path 20 is a passage extending from near the upper end of the separating inclined section 22 provided in the paper feed tray 16 to the recording section 24. The curved path 20 includes an outer guide member 18 and an inner guide member 19. The outer guide member 18 and the inner guide member 19 face each other at a predetermined distance. The first conveyor roller 45 is formed continuously over the entire range in the left-right direction through which the recording paper 21 can pass (hereinafter referred to as the "image recording range") by, for example, ceramic-coating the outer peripheral surface of the conveyor shaft 49. The first conveyor roller 45 and the pinch roller 46 are disposed between the curved path 20 and the platen 34. The first conveyor roller 45 and the pinch roller 46 are in pressure contact with each other. The first conveyor roller 45 is rotated by a rotational driving force transmitted from the conveyor motor 29 via the drive transmission mechanism 33. The first conveyor roller 45 and the pinch roller 46 convey the recording paper 21 that has passed through the curved path 20 onto the platen 34.

[0025] The first conveyor roller 45 is fitted onto a conveyor shaft 49. As shown in FIG. 21, a rotary encoder 53 is provided on the left end of the conveyor shaft 49. The rotary encoder 53 has a disk 54 and an optical sensor 55. The disk 54 is fitted onto the conveyor shaft 49 and rotates integrally therewith. The disk 54 has slits formed at equal intervals along the circumferential direction. The optical sensor 55 is disposed opposite the disk 54. The optical sensor 55 outputs a pulse signal to the control unit 23, the signal level of which changes in two stages depending on the presence or absence of the slits. The control unit 23 counts the number of pulses to obtain the amount of rotation of the conveyor shaft 49 (first conveyor roller 45).

[0026] The recording unit 24 uses an inkjet system to eject liquid (ink) and record an image on the recording paper 21. The recording unit 24 is disposed above the paper feed tray 16. As shown in FIG. 3, the recording unit 24 includes a recording head 30, a carriage 31, guide rails 35 and 36, and a maintenance unit 50. The carriage 31 includes a read head 58. An encoder strip 57 is attached to the guide rail 36 along the left-right direction. The carriage 31 is guided by the guide rails 35 and 36 and moves back and forth in the left-right direction by the rotational driving force of the carriage motor 32. The read head 58 reads the encoder strip 57 and outputs a pulse signal in accordance with the movement of the carriage 31. The encoder strip 57 and the read head 58 form a linear encoder 59. As an initial operation when the power is turned on, the linear encoder 59 moves the carriage 31 from the home position at the right end of the reciprocating movement range to the left end, and when the carriage 31 abuts against the left end of the reciprocating movement range, it initializes the count value of the pulse signal to 0. The linear encoder 59 detects the position of the carriage 31 by counting the pulse signal, with the left end of the reciprocating movement range of the carriage 31 as the zero point.

[0027] The recording head 30 is mounted on a carriage 31. As shown in FIG. 4, a plurality of nozzles 40 are formed on a nozzle surface 41, which is the underside of the recording head 30. Each nozzle 40 ejects ink of one of the colors cyan (C), magenta (M), yellow (Y), and black (Bk). The nozzles 40 corresponding to each color ink of CMYBk are aligned in a line along the front-to-rear direction, and each row of nozzles 40 corresponding to each color ink is aligned in the left-to-right direction. The number of nozzles 40 and their pitch in the front-to-rear direction are set appropriately depending on the resolution of the recorded image, etc.

[0028] 4, rows of nozzles 40 corresponding to the four colors of ink, CMYBk, are formed on the nozzle surface 41, but the number of rows of nozzles 40 can be increased or decreased depending on the number of colors of ink used. Ink of each color, cyan (C), magenta (M), yellow (Y), and black (Bk), is supplied to the recording head 30 from ink cartridges through ink tubes. The recording head 30 ejects ink while scanning the recording paper 21 on the platen 34 as the carriage 31 moves back and forth, recording an image.

[0029] The paper discharge path 37 has a lower guide member 38 and an upper guide member 39. The lower guide member 38 and the upper guide member 39 face each other with a predetermined gap between them. The second conveyor roller 47 and the spur roller 48 are disposed between the platen 34 and the lower guide member 38. The second conveyor roller 47 is fitted onto the discharge shaft 60 at multiple locations along the axial direction. The second conveyor roller 47 and the spur roller 48 are in pressure contact with each other. The second conveyor roller 47 rotates when the rotational driving force of the first conveyor roller 45 is transmitted to it. The second conveyor roller 47 and the spur roller 48 convey the recording paper 21 on which an image has been recorded to the paper discharge tray 17.

[0030] The maintenance unit 50 performs maintenance on the recording head 30. The maintenance unit 50 includes a purge mechanism 42 (FIG. 5A). The purge mechanism 42 is disposed to the right of the image recording range. When the carriage 31 moves to the right end of its reciprocating movement range, the purge mechanism 42 performs a purge suction operation to suck and remove air bubbles and foreign matter along with ink from the nozzles 40 of the recording head 30. The purge mechanism 42 includes a cap 43, a lift-up mechanism 44, a pump mechanism 51, and an ink discharge tube 52.

[0031] The lift-up mechanism 44 moves the cap 43 toward and away from the nozzle surface 41 of the recording head 30. The lift-up mechanism 44 has a holder 81. The holder 81 has an abutment lever 80. The abutment lever 80 protrudes vertically upward. The holder 81 holds the cap 43. When the abutment lever 80 is pressed rightward as the carriage 31 moves to the right end of its reciprocating movement range, the holder 81 moves to the position shown in FIG. 5B, bringing the cap 43 into close contact with the nozzle surface 41 of the recording head 30. When the carriage 31 moves leftward from the right end of its reciprocating movement range and the pressure on the abutment lever 80 is released, the holder 81 moves to the position shown in FIG. 5A, and the cap 43 moves away from the recording head 30.

[0032] In FIG. 5B, the cap 43 is in close contact with the nozzle surface 41, forming a sealed space. The pump mechanism 51 is, for example, a rotary tube pump. The pump mechanism 51 and the sealed space of the cap 43 are in communication with each other using a tube (not shown). The pump mechanism 51 is driven by the transport motor 29, and applies negative pressure to the sealed space of the cap 43 to perform a purge suction operation. The sucked ink and the like are discharged through the ink discharge tube 52 to a waste liquid tank (not shown). The pump mechanism 51 is driven by the transport motor 29.

[0033] The control unit 23 monitors and controls the operation of the multifunction device 10. The control unit 23 is a so-called computer mainly consisting of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), EEPROM (Electrically Erasable Programmable ROM), and ASIC (Application Specific Integrated Circuit). The ROM and EEPROM are non-volatile storage elements, while the RAM is a volatile storage element that can be read and written at high speed. The CPU reads a program from the ROM and executes the program using the RAM as a working storage area. The CPU may read operating parameters of the program from the EEPROM. The CPU operates the ASIC in accordance with the program.

[0034] As shown in FIG. 6 , the ASIC of the control unit 23 is electrically connected to the conveyance motor 29, the recording head 30, the carriage motor 32, the rotary encoder 53, and the read head 58. The ASIC has a drive circuit that controls the conveyance motor 29 and the carriage motor 32 and the recording head 30. The control unit 23 receives pulse signals from the rotary encoder 53 and the read head 58 using the ASIC. Using the pulse signals, the control unit 23 obtains the amount of rotation of the first conveyance roller 45, the relative movement distance and current position of the carriage 31 with respect to the guide rail 36, and controls the conveyance motor 29 and the carriage motor 32. When the position of the carriage 31 is controlled in this manner, the first switching mechanism 64 switches the transmission destination of the rotational drive force of the conveyance motor 29 between the rotation cam mechanism 130 and the pump mechanism 51, and the paper feed drive transmission mechanism 27. Furthermore, the transmission cut-off mechanism 140 switches between transmitting the rotational driving force of the conveying motor 29 to the rotation cam mechanism 130 and cutting off the transmission.

[0035] [Structure of recording head 30] 7 and 8, the recording head 30 includes, for each of the colors CMYBk, a supply flow path 100, a first air trap chamber 101, a second air trap chamber 102, a manifold 103, an ink supply hole 104, an exhaust flow path 107, and an exhaust port 108. The following description will be given using one of the colors CMYBk as an example, but the details are common to all four colors.

[0036] The manifold 103 is a flow path that extends in the front-to-rear direction along the multiple nozzles 40 on the FE (Front End) side of the recording head 30. The manifold 103 is in communication with these multiple nozzles 40. The first air trap chamber 101 is in communication with a first end 103a at the front of the manifold 103 and extends upward from the first end 103a. The second air trap chamber 102 is in communication with a second end 103b at the rear of the manifold 103 and extends upward from the second end 103b. The supply flow path 100 is a flow path that extends in the front-to-rear direction on the BE (Back End) side of the recording head 30.

[0037] The supply flow path 100 communicates with the first air trap chamber 101 via a first opening 101a. The supply flow path 100 communicates with the second air trap chamber 102 via an opening 102a. The first volume of the first air trap chamber 101 and the second volume of the second air trap chamber 102 are approximately the same. The cross-sectional areas of the first air trap chamber 101 and the second air trap chamber 102 in a horizontal cross section are both large enough to prevent the formation of a meniscus of ink or the like. A filter (not shown) is disposed at the bottom end of each of the first air trap chamber 101 and the second air trap chamber 102. The filter prevents foreign matter from entering the manifold 103 and clogging the nozzle 40.

[0038] The first flow path 100a is a flow path in the supply flow path 100 that connects the ink supply hole 104 to the first air trap chamber 101. The first flow path 100a includes a first opening 101a at the upper end of the first air trap chamber 101. A first valve 131, which will be described later, opens and closes the first flow path 100a by opening and closing the first opening 101a. The second flow path 100b is a flow path in the supply flow path 100 that connects the ink supply hole 104 to the second air trap chamber 102. The second openings 105 and 106 are located between the upper end of the first air trap chamber 101 and the upper end of the second air trap chamber 102. The second flow path 100b includes the second openings 105 and 106. A second valve 132, which will be described later, opens and closes the second flow path 100b by opening and closing the second opening 105. Hereinafter, a state in which the first valve 131 closes the first flow path 100a and the second valve 132 opens the second flow path 100b will be referred to as a "first state." A state in which the first valve 131 opens the first flow path 100a and the second valve 132 closes the second flow path 100b will be referred to as a "second state." Furthermore, a state in which the first valve 131 opens the first flow path 100a and the second valve 132 opens the second flow path 100b will be referred to as a "third state." The first state, the second state, and the third state can be selectively switched.

[0039] The ink supply hole 104 is a through-hole that receives ink from an ink cartridge. The received ink passes through the supply channel 100, the first air trap chamber 101, and the second air trap chamber 102, and is supplied to the manifold 103 from both the first end 103a and the second end 103b. The first air trap chamber 101 is located upstream of the second air trap chamber 102 in the ink flow direction in the supply channel 100. The first air trap chamber 101 and the second air trap chamber 102 collect air bubbles (air) contained in the ink. The exhaust channel 107 connects the upper end of the second air trap chamber 102 to the exhaust port 108. Air remaining at the upper ends of the first air trap chamber 101 and the second air trap chamber 102 is exhausted from the exhaust port 108 via the exhaust channel 107.

[0040] As an example of a mechanism for driving the first valve 131 and the second valve 132 for each of the CMYBk colors, a mechanism using eight solenoids 200 to drive the first valve 131 and the second valve 132 is conceivable, as shown in FIG. 9 . However, installing eight solenoid valves in series would inevitably increase the size of the multifunction printer 10, and would also inevitably increase costs. For this reason, in this disclosure, the first valve 131 and the second valve 132 are driven using a rotating cam mechanism 130 as described below. Note that the configuration and operation of the cam mechanism according to this embodiment are common to all of the CMYBk colors, and therefore, the following description will be given for only one color without specifying the ink color, and will also serve as a description for the other three colors.

[0041] [Configuration of the rotating cam mechanism 130] The rotating cam mechanism 130 according to this embodiment utilizes a conveying motor 29. As shown in FIGS. 10 to 17, the rotating cam mechanism 130 includes a first valve 131, a second valve 132, a valve holder 133, a rotating cam 134, a first coil spring (not shown), a second coil spring (not shown), and a rubber sheet 137. The first valve 131 includes a first valve stem portion 131a, a first valve arm portion 131b, and a first valve head portion 131c. Because the first opening 101a has a larger diameter than the outer diameter of the first valve stem portion 131a, the first valve head portion 131c is provided with a larger diameter than the first opening 101a. The first coil spring is housed in the upper portion of the first cylindrical portion 133a of the valve holder 133. The first coil spring biases the first valve 131 toward the first opening 101a.

[0042] The second valve 132 has a second valve stem portion 132a and a second valve arm portion 132b. The second coil spring is housed in the upper portion of the second cylindrical portion 133b of the valve holder 133. The second coil spring biases the second valve 132 toward the second opening 105. The rubber sheet 137 seals the gap between the first valve head portion 131c and the first opening 101a when the first valve head portion 131c closes the first opening 101a. The rubber sheet 137 also seals the gap between the second valve stem portion 132a and the second opening 105 when the second valve stem portion 132a closes the second opening 105. When the first opening 101a and the second opening 105 are not closed, the rubber sheet 137 elastically restores its original shape and retracts upward so as not to interfere with the flow of ink.

[0043] 11, the first arm portion 131b and the second arm portion 132b are L-shaped when viewed from above. The first arm portion 131b protrudes rearward from a slit 133a1 provided at the rear of the first cylindrical portion 133a of the valve holder 133, then bends 90 degrees to the right, and abuts from above on the circumferential surface of the first cam portion 134a. The second arm portion 132b protrudes forward from a slit 133b1 provided at the front of the second cylindrical portion 133b of the valve holder 133, then bends 90 degrees to the left, and abuts from above on the circumferential surface of the second cam portion 134b.

[0044] As shown in FIG. 13(A), the rotating cam 134 is a member that is elongated in the front-rear direction. The rotating cam 134 has a first cam portion 134a, a second cam portion 134b, a rotation shaft 134c, and a bladed gear 134d. The first cam portion 134a and the second cam portion 134b are fitted to the rotation shaft 134c and rotate in the rotation direction Dr. In this embodiment, as shown in FIG. 13(B), the first cam portion 134a and the second cam portion 134b have the same shape. The first cam portion 134a and the second cam portion 134b are fitted to each other at an angle of 120 degrees with respect to the center of rotation in a plan view from the rotation shaft direction. In the first direction Da, the first cam portion 134a has a small diameter R2, and the second cam portion 134b has a large diameter R1. In the second direction Db, the first cam portion 134a has a large diameter R1 and the second cam portion 134b has a small diameter R2. In the third direction Dc, both the first cam portion 134a and the second cam portion 134b have the large diameter R1. The first direction Da, the second direction Db, and the third direction Dc are all shifted by 120 degrees from each other with respect to the center of rotation.

[0045] When the portion of the first cam portion 134a and the second cam portion 134b with the large diameter R1 faces upward, that portion becomes a first height H1. When the portion of the first cam portion 134a and the second cam portion 134b with the small diameter R2 faces upward, that portion becomes a second height H2 that is lower than the first height H1. Therefore, when the first direction Da faces upward, as shown in FIG. 15(B), the first valve 131 is pushed downward by the biasing force of the first coil spring, and the first opening 101a is closed. As shown in FIG. 15(A), the second valve 132 is pushed upward against the biasing force of the second coil spring, and the second opening 105 is opened (first state). When the second direction Db is directed upward, as shown in FIG. 16(B), the first valve 131 is pushed upward against the biasing force of the first coil spring, and the first opening 101a is opened. As shown in FIG. 16(A), the second valve 132 is pushed downward by the biasing force of the second coil spring, and the second opening 105 is closed (second state). When the third direction Dc is directed upward, as shown in FIG. 17(B), the first valve 131 is pushed upward against the biasing force of the first coil spring, and the first opening 101a is opened. As shown in FIG. 17(B), the second valve 132 is also pushed upward against the biasing force of the second coil spring, and the second opening 105 is opened (third state).

[0046] [Drive mechanism of the rotation cam mechanism 130] As shown in Figures 10 and 11, a bladed gear 134d is fitted to the front end of the rotation shaft 134c of the rotating cam 134. The bladed gear 134d has a blade 134d1 on its front bottom surface. The width of the blade 134d1 corresponds to a portion of the entire circumference of the bladed gear 134d. An optical sensor 134d2 is disposed on either side of a position through which the blade 134d1 passes as the bladed gear 134d rotates. The optical sensor has a light source and a photosensor. The light source emits detection light toward the photosensor. The photosensor outputs a detection signal according to the amount of incident light. The optical sensor 134d2 is disposed so that the optical path of the detection light from the light source to the photosensor intersects with the position through which the blade 134d1 passes. When the blade 134d1 blocks the detection light of the optical sensor 134d2, the amount of light detected by the photosensor changes. The rotation angle of the rotating cam 134 is controlled using the angular position (on-edge or off-edge) at which the amount of light detected by the photosensor changes as a reference position.

[0047] As shown in FIGS. 18 to 20, the printer unit 11 has a transmission interruption mechanism 140. The transmission interruption mechanism 140 has a first gear 141, a second gear 142, a third gear 143, a planetary gear mechanism 144, and a fourth gear 145. The second gear 142 is a so-called reduction gear. The second gear 142 has a first sub-gear 142a and a second sub-gear 142b that share a rotational axis. The number of teeth of the first sub-gear 142a is greater than the fraction of the number of teeth of the second sub-gear 142b. The planetary gear mechanism 144 has a sun gear 144a, a planetary gear 144b, and a planetary carrier 144c. The planetary carrier 144c is pivotally attached to the rotational axis of the sun gear 144a. The planetary carrier 144c supports the planetary gear 144b. The first gear 141, the second gear 142, the third gear 143, the sun gear 144a, the planetary gear 144b, and the fourth gear 145 are so-called idle gears.

[0048] The first gear 141 meshes with the pump drive gear 146 and the first sub gear 142a of the purge mechanism 42. The second sub gear 142b meshes with the third gear 143. The third gear 143 meshes with the second sub gear 142b and the sun gear 144a. The sun gear 144a meshes with the third gear 143 and the planet gear 144b. The planet gear 144b revolves around the sun gear 144a while rotating on its own axis. The number of teeth of the planet gear 144b is fewer than the number of teeth of the sun gear 144a. Therefore, the planet gear 144b revolves in the same direction as the rotation direction of the sun gear 144a. This revolution causes the planetary gear mechanism 144 to swing in the directions of arrows Dp1 and Dp2 around the rotation axis of the sun gear 144a. This swing causes the planetary gear 144b and the fourth gear 145 that drives the rotating cam 134 to come into contact with and separate from each other.

[0049] Specifically, when the carry motor 29 rotates forward, the planetary gear mechanism 144 swings in the direction of the arrow Dp1, the planetary gear 144b moves away from the fourth gear 145, and the forward rotation of the carry motor 29 is no longer transmitted to the rotating cam 134. When the carry motor 29 rotates reversely, the planetary gear mechanism 144 swings in the direction of the arrow Dp2, and the planetary gear 144b meshes with the fourth gear 145. The feathered gear 134d is attached to the recording head 30 and moves back and forth together with the carriage 31. When the carriage 31 reaches the right end of its reciprocating movement range, the feathered gear 134d meshes with the fourth gear 145. As a result, the reverse rotation of the carry motor 29 is transmitted to the rotating cam 134. In this way, the planetary gear mechanism 144 constitutes a switching mechanism that does not transmit the forward rotation of the conveying motor 29 to the rotating cam 134 but transmits the reverse rotation of the conveying motor 29 to the rotating cam 134 .

[0050] [Driving operation of the rotating cam mechanism 130] The pump drive gear 146 is fitted onto a rotary shaft 66, which will be described later. The pump drive gear 146 is rotationally driven by the conveying motor 29 via the rotary shaft 66. The transmission interruption mechanism 140 transmits the rotational driving force of the conveying motor 29 from the pump drive gear 146 to the bladed gear 134d, or interrupts the transmission of the rotational driving force. This causes the rotating cam 134 to rotate.

[0051] [Purge suction operation] During the purge suction operation, the control unit 23 rotates the conveying motor 29 in the forward direction, as shown in FIG. 18, thereby rotating the pump drive gear 146 in the direction of the arrow 146a. The pump drive gear 146 drives the pump mechanism 51, generating a negative pressure (suction pressure) in the space covered by the cap 43 and performing the purge suction operation. The pump drive gear 146 also transmits the rotational drive force to the transmission interruption mechanism 140. As a result, the rotational drive force is transmitted to the sun gear 144a via the first gear 141, the second gear 142, and the third gear 143, causing the planetary gear mechanism 144 to swing in the direction of the arrow Dp1. This interrupts the transmission of the rotational drive force from the conveying motor 29 to the bladed gear 134d. The planetary stopper 144d restricts the swing of the planetary gear mechanism 144 in the direction of the arrow Dp1. Therefore, the planetary gear 144b does not mesh with the fourth gear, and therefore, the states of the first valve 131 and the second valve 132 can be prevented from switching during the purge suction operation.

[0052] [Pump release operation] During the pump atmosphere opening operation, the control unit 23 rotates the conveying motor 29 in the direction opposite to that during the purge suction operation, as shown in FIG. 19, thereby rotating the pump drive gear 146 in the direction of the arrow 146b. The pump drive gear 146 rotates the pump mechanism 51 to perform the pump atmosphere opening operation, which opens the inside of the tube to the atmosphere. This releases the negative pressure applied to the space covered by the cap 43, opening the space to the atmosphere. The rotational drive force of the conveying motor 29 is also transmitted to the transmission interruption mechanism 140, causing the planetary gear mechanism 144 to swing in the direction of the arrow Dp2. However, during the pump atmosphere opening operation, because the number of drive pulses of the conveying motor 29 is small, the swing of the planetary gear mechanism 144 remains within a range where the planetary gear 144b does not mesh with the fourth gear 145. This prevents the states of the first valve 131 and the second valve 132 from switching.

[0053] [Valve switching operation] When switching the open / closed states of the first valve 131 and the second valve 132, the control unit 23 further drives the conveying motor 29 in the reverse direction after the pump has been vented to the atmosphere. As shown in FIG. 20 , the planetary gear mechanism 144 further swings in the direction of the arrow Dp2, causing the planetary gear 144b to mesh with the fourth gear 145. The reverse driving force of the conveying motor 29 is then transmitted to the bladed gear 134d. In the purge mechanism 42, no problems occur with the pump even if the pump drive gear 146 rotates toward the side where the pump is vented to the atmosphere. Therefore, by rotating the conveying motor 29 in the reverse direction, the control unit 23 detects the reference position of the rotation angle of the rotating cam 134, as described above, and then switches the open / closed states of the first valve 131 and the second valve 132.

[0054] [Drive configuration of purge mechanism 42] Various drive configurations can be used for the purge mechanism 42 used to rotate the rotating cam 134. The drive configuration of the purge mechanism 42 described below is one example, but it goes without saying that other drive configurations may also be used.

[0055] As shown in FIG. 21 , the paper feed shaft 28, the conveying shaft 49, and the discharge shaft 60 have their longitudinal directions extending left to right. The conveying motor 29 is disposed behind the paper feed shaft 28. A motor gear 61 is fitted to the drive shaft of the conveying motor 29. A roller gear 62 is fitted to the left end of the conveying shaft 49. The motor gear 61 and the roller gear 62 mesh with each other to transmit the driving force of the conveying motor 29 to the conveying shaft 49. A drive gear 63 is fitted to the right end of the paper feed shaft 28. The drive gear 63 transmits the rotation of the paper feed shaft 28 to a first switching mechanism 64. The first switching mechanism 64 has a driven gear 65. The first switching mechanism 64 is interposed between the drive gear 63 and the driven gear 65, and switches whether or not the rotation of the drive gear 63 is transmitted to the driven gear 65. The driven gear 65 is fitted onto a rotary shaft 66. When the driven gear 65 is driven to rotate, the rotary shaft 66 is driven to rotate.

[0056] The first switching mechanism 64 has a frame 67, a shaft 68, a first moving gear 69, a second moving gear 70, an abutment member 71, a left coil spring 72, a right coil spring 73, and a lever 74. The frame 67 accommodates the shaft 68, the first moving gear 69, the second moving gear 70, the abutment member 71, the left coil spring 72, and the right coil spring 73. The frame 67 supports the shaft 68. The axial direction of the shaft 68 is the left-right direction. The shaft 68 supports the first moving gear 69 at its left end. The first moving gear 69 can mesh with the drive gear 63 through an opening (not shown) in the frame 67. The second moving gear 70 is supported by the shaft 68 to the right of the first moving gear 69. The second moving gear 70 can move in the axial direction. This movement allows the second moving gear 70 to mesh with the driven gear 65 through another opening (not shown) in the frame 67 (FIG. 22(A)). When the second moving gear 70 moves out of this meshing position, it is disengaged from the driven gear 65. The shaft 68, the first moving gear 69, and the second moving gear 70 rotate together. The first moving gear 69 and the second moving gear 70 move together in the axial direction.

[0057] The abutment member 71 is loosely fitted onto the shaft 68 on the right side of the second moving gear 70. The abutment member 71 is movable in the axial direction. The abutment member 71 has a lever 74. The lever 74 extends upward from the abutment member 71. The tip of the lever 74 is located on the right side of the image recording range and on the movement path of the carriage 31. A left coil spring 72 and a right coil spring 73 are wound around the shaft 68. The left end of the left coil spring 72 is fixed to a fixing member (not shown) that is integral with the frame. Similarly, the right end of the right coil spring 73 is fixed. The left coil spring 72 presses against the left side of the second moving gear 70, urging the second moving gear 70 to the right. The right coil spring 73 presses against the right side of the abutment member 71, urging the abutment member 71 to the left. As a result, the abutting member 71 abuts against the second moving gear 70. Because the biasing force of the right coil spring 73 is greater than the biasing force of the left coil spring 72, when no external force is applied to the lever 74, the right coil spring 73 elastically compresses the left coil spring 72, and the second moving gear 70 is positioned to the left of the driven gear 65, where it does not mesh with the driven gear 65 (FIG. 22(B)).

[0058] As the carriage 31 moves to the right of the image recording range toward the right end of its reciprocating movement range (home position, capping position), the protrusion 79 presses the lever 74 to the right, moving the abutment member 71 to the right. Then, the biasing force of the left coil spring 72 causes the second moving gear 70 to move to the right and mesh with the driven gear 65. The driving force of the conveying motor 29 is transmitted to the pump driving gear 146 via the driving gear 63, the first moving gear 69, the second moving gear 70, the driven gear 65, and the rotating shaft 66, thereby driving the pump mechanism 51. Needless to say, when the second moving gear 70 and the driven gear 65 are not meshed, the driving force of the conveying motor 29 is not transmitted to the pump driving gear 146. In this way, the first switching mechanism 64 switches between a first position in which the rotation of the conveying shaft 49 is transmitted to the pump drive gear 146 and a second position in which the rotation of the conveying shaft 49 is not transmitted to the pump drive gear 146. In addition, in the first position, as described above, the purge suction operation, the pump atmosphere opening operation, and the valve switching operation are performed.

[0059] [Exhaust operation] 23, the recording head 30 has exhaust ports 75Y, 75M, 75C, and 75Bk, on-off valves 76Y, 76M, 76C, and 76Bk, biasing means 77Y, 77M, 77C, and 77Bk, and needles 78Y, 78M, 78C, and 78Bk for each of the Y, M, C, and Bk inks, to exhaust air trapped in the first air trap chamber 101 and the second air trap chamber 102 through the exhaust port 108. The biasing means 77Y, 77M, 77C, and 77Bk bias the on-off valves 76Y, 76M, 76C, and 76Bk downward to close the exhaust ports 75Y, 75M, 75C, and 75Bk.

[0060] During exhaust, the exhaust ports 75Y, 75M, 75C, and 75Bk are first covered with the caps 43. Next, the needles 78Y, 78M, 78C, and 78Bk press the on-off valves 76Y, 76M, 76C, and 76Bk, moving them upward. This opens the exhaust ports 75Y, 75M, 75C, and 75Bk. In this state, YMCBk inks are supplied and suction is performed by the pump mechanism 51, causing air to be exhausted through the exhaust ports 108. Once exhaust is complete, the needles 78Y, 78M, 78C, and 78Bk descend to release pressure on the on-off valves 76Y, 76M, 76C, and 76Bk, causing the on-off valves 76Y, 76M, 76C, and 76Bk to close the exhaust ports 75Y, 75M, 75C, and 75Bk. Thereafter, when the pump mechanism 51 is opened to the atmosphere, the cap 43 descends, and the cover on the exhaust ports 75Y, 75M, 75C, and 75Bk is released.

[0061] [Purge suction operation] During purge suction, the control unit 23 first rotates the carriage motor 32 to move the carriage 31 to the right end of its reciprocating range. As a result, the carriage 31 presses the contact lever 80 of the lift-up mechanism 44, bringing the cap 43 into close contact with the nozzle surface 41 (FIG. 5B). The protrusion 79 of the carriage 31 presses the lever 74 to the right, moving the contact member 71 to the right, and the second moving gear 70 meshes with the driven gear 65. As a result, the driving force of the conveyance motor 29 is transmitted to the pump driving gear 146 via the driving gear 63, the first moving gear 69, the second moving gear 70, the driven gear 65, and the rotating shaft 66 (FIG. 22A). The bladed gear 134d also meshes with the fourth gear of the transmission interruption mechanism 140. Next, the control unit 23 rotates the conveyance motor 29 in the direction opposite to that during the purge suction operation. This causes the planetary gear 144b of the planetary gear mechanism 144 to revolve and mesh with the fourth gear 145, causing the bladed gear 134d to rotate. The control unit 23 monitors the output signal of the optical sensor 134d2 to detect an on-edge or off-edge and determine the reference position of the rotation angle of the rotating cam 134. While monitoring the output of the rotary encoder 53, the control unit 23 rotates the conveyance motor 29, causing the first direction Da of the rotating cam 134 to face upward. This places the recording head 30 in the first state. When the control unit 23 rotates the conveyance motor 29 in the forward direction, the planetary gear 144b of the planetary gear mechanism 144 revolves and disengages from the fourth gear 145, causing the bladed gear 134d to stop rotating. Therefore, even if the control unit 23 drives the transport motor 29 to rotate in the forward direction, the recording head 30 is maintained in the first state.

[0062] When the control unit 23 further drives the transport motor 29 in the forward direction, the pump mechanism 51 applies negative pressure to the sealed space in the cap 43, performing a purge suction operation. In the first state, the first valve 131 closes the first opening 101a, and the second valve 132 opens the second opening 105. This causes ink to be drawn into the manifold 103 from the ink supply hole 104 via only the second flow path 100b. This allows foreign matter, air bubbles, and residual ink that has become viscous due to drying to be expelled. Because ink is not drawn into the manifold 103 from the first opening 101a, inks do not merge within the manifold 103. This prevents a decrease in the ink flow rate, preventing air bubbles from remaining. The expelled foreign matter and other contaminants are sent to the waste tank via the ink discharge tube 52. After the foreign matter and other contaminants are expelled, the control unit 23 drives the transport motor 29 in the reverse direction to open the pump to the atmosphere.

[0063] The control unit 23 again drives the conveyance motor 29 to rotate in the direction opposite to that during the purge suction operation, causing the fourth gear to mesh with the bladed gear 134d and driving the bladed gear 134d to rotate. The control unit 23 monitors the output signal of the optical sensor 134d2 and determines the reference position of the rotation angle of the rotating cam 134. The control unit 23 drives the conveyance motor 29 to rotate, and points the second direction Db of the rotating cam 134 upward. This puts the recording head 30 into the second state. When the control unit 23 drives the conveyance motor 29 to rotate in the forward direction, the bladed gear 134d is disengaged from the fourth gear 145 and is no longer driven to rotate, so the recording head 30 is maintained in the second state.

[0064] The control unit 23 further drives the transport motor 29 to rotate in the forward direction, causing the pump mechanism 51 to perform a purge suction operation. In the second state, the first opening 101a is opened by the first valve 131, and the second opening 105 is closed by the second valve 132, so that ink is sucked into the manifold 103 from the ink supply hole 104 via only the first flow path 100a, and foreign matter and the like are discharged. Because ink is not sucked into the manifold 103 from the second opening 105, the inks do not merge within the manifold 103, and the ink flow rate does not decrease, preventing air bubbles from remaining. After sending the discharged foreign matter and the like to the waste liquid tank, the control unit 23 drives the transport motor 29 to rotate in the reverse direction, thereby venting the pump to the atmosphere.

[0065] In this embodiment, the recording head 30 is sequentially switched between the first state and the second state to discharge foreign matter, etc., but it goes without saying that the present disclosure is not limited to this, and at each discharge timing, foreign matter, etc. may be discharged in only one of the first state or the second state, and the first state and the second state may be switched each time the discharge timing occurs.

[0066] Thereafter, the control unit 23 drives the conveyance motor 29 to rotate in the reverse direction, similarly to the above, to rotate the feathered gear 134d and determine the reference position of the rotation angle of the rotating cam 134. When the control unit 23 rotates the conveyance motor 29 in the reverse direction to rotate the feathered gear 134d and orient the third direction Dc of the rotating cam 134 upward, the recording head 30 enters the third state. In the third state, both the first opening 101a and the second opening 105 are opened, so that ink can be supplied to the manifold 103 from both the first opening 101a and the second opening 105. When the control unit 23 drives the carriage motor 32 to rotate and move the carriage 31 from the right end of the reciprocating movement range to the left, the feathered gear 134d and the fourth gear are disengaged. Furthermore, the carriage 31 is released from pressing the contact lever 80 of the lift-up mechanism 44, and the cap 43 moves away from the nozzle surface 41 of the recording head 30. This makes it possible to record an image.

[0067] [Effects of the embodiment] In a configuration in which ink is supplied from only one end of the manifold 103, increasing the number of nozzles 40 provided on the nozzle surface 41 of the recording head 30 increases the amount of ink ejected from the nozzles 40, which can make it difficult for ink to reach the nozzles 40 at the end, resulting in the risk of under-refill. For this reason, it is necessary to increase the amount of ink supplied to the manifold 103 that communicates with the nozzles 40. To meet this requirement, a configuration in which ink is supplied from both ends of the manifold 103 can be considered. This configuration increases the amount of ink supplied and prevents under-refill. However, during the purge suction operation, the ink flow rate decreases where the inks in the manifold 103 join together, making it difficult to remove air bubbles that have adhered to the inner wall of the manifold 103.

[0068] The multifunction device 10 according to the present disclosure uses a cam mechanism to selectively switch the first valves 121, 131 and the second valves 122, 132 between a first state and a second state, allowing ink to be supplied from only one end of the manifold 103. Performing a purge suction operation in the first state or the second state prevents ink flowing in opposite directions from merging in the manifold 103. This prevents the ink flow rate within the manifold 103 from slowing down, ensuring that even air bubbles adhering to the inner wall can be discharged.

[0069] Furthermore, in a configuration in which eight solenoid valves are installed as the first valves 121, 131 and the second valves 122, 132, a new drive source must be installed for each valve. This inevitably increases the size of the multifunction printer 10 and increases the cost of parts and manufacturing. On the other hand, if a cam mechanism is used, the already installed transport motor 29 and carriage motor 32 can be utilized. This prevents the multifunction printer 10 from becoming larger and the cost from increasing.

[0070] [Variations] (1) In the above embodiment, the first valve 131 and the second valve 132 are opened and closed using the rotary cam mechanism 130 that utilizes the conveying motor 29. However, instead of this, the linear cam mechanism 120 may be used as follows. In the following, common reference numerals will be used to designate common members, etc., between the rotary cam mechanism 130 and the linear cam mechanism 120. [Configuration of the linear cam mechanism 120] The linear cam mechanism 120 according to this modification utilizes a carriage motor 32. As shown in FIGS. 24 to 36, the linear cam mechanism 120 includes a first valve 121, a second valve 122, a valve holder 123, a linear cam 124, a first coil spring 121d, a second coil spring 122d, and a rubber sheet 127. The first valve 121 includes a first valve stem portion 121a, a first valve arm portion 121b, and a first valve head portion 121c. Because the first opening 101a has a larger diameter than the outer diameter of the first valve stem portion 121a, the first valve head portion 121c is provided with a larger diameter than the first opening 101a.

[0071] The first coil spring 121d biases the first valve 121 toward the first opening 101a. The second valve 122 has a second valve stem portion 122a and a second valve arm portion 122b. The second coil spring 122d biases the second valve 122 toward the second opening 105. When the first valve head portion 121c closes the first opening 101a, the rubber sheet 127 seals the gap between the first valve head portion 121c and the first opening 101a. When the second valve stem portion 122a closes the second opening 105, the rubber sheet 127 seals the gap between the second valve stem portion 122a and the second opening 105. When the first opening 101a and the second opening 105 are not closed, the rubber sheet 127 elastically restores its original shape and retreats upward so as not to interfere with the flow of ink.

[0072] As shown in FIG. 25, the rectilinear cam 124 is a member that is elongated in the front-rear direction. The first arm 121b abuts against a first region 124a along one widthwise side of the upper surface (contact surface) of the rectilinear cam 124, and the second arm 122b abuts against a second region 124b along the other widthwise side. The height (vertical position) of the abutment surface of the rectilinear cam 124 changes along the front-rear direction between a first height H1 and a second height H2 that is lower than the first height H1. The region between the first height H1 and the second height H2 in the front-rear direction forms an inclined surface that guides the first arm 121b and the second arm 122b from one height region to the other height region. The rectilinear cam 124 is a slide cam that displaces (slides) left and right relative to the first valve 121 and the second valve 122. This displacement causes the contact position of the first arm portion 121b and the second arm portion 122b on the linear cam 124 to change.

[0073] When the contact surface of the first arm portion 121b at the contact position of the rectilinear cam 124 is at the first height H1 (FIGS. 25, 26(A), and 28(A)), the first valve 121 is pushed upward against the biasing force of the first coil spring 121d (FIGS. 26(B) and 28(B)). This opens the first opening 101a. Similarly, when the contact surface of the second arm portion 122b at the contact position of the rectilinear cam 124 is at the first height H1 (FIGS. 25, 27(A), and 28(A)), the second valve 122 is pushed upward against the biasing force of the second coil spring 122d (FIGS. 27(B) and 28(B)). This opens the second opening 105. Furthermore, when the contact surface of the first arm portion 121b is at the contact position and is at the second height H2 (FIG. 27(A)), the first valve 121 is pressed downward by the biasing force of the first coil spring 121d (FIG. 27(B)). This closes the first opening 101a. Similarly, when the contact surface of the second arm portion 122b is at the contact position and is at the second height H2 (FIG. 26(A)), the second valve 122 is pressed downward by the biasing force of the second coil spring 122d (FIG. 26(B)). This closes the second opening 105.

[0074] Within the range in which the first arm 121b and the second arm 122b abut against each other in the front-rear direction, at least one of the first and second regions of the upper surface of the rectilinear cam 124 is always at the first height H1. Therefore, even if the first valve 121 and the second valve 122 move back and forth in the up-down direction, the rectilinear cam 124 moves left and right relative to the first valve 121 and the second valve 122. Therefore, even if the first valve 121 and the second valve 122 move back and forth in the up-down direction, both the first opening 101a and the second opening 105 are never closed at the same time. At least one of the first opening 101a and the second opening 105 is always open. When the first opening 101a is closed, as shown in FIG. 29, ink supplied to the ink supply hole 104 can bypass the first valve head 121c and flow into the second opening 105. Therefore, ink can always flow through at least one of the first flow path 100a and the second flow path 100b.

[0075] [Operation of the linear cam mechanism 120] As shown in FIG. 30 , a right-end protrusion 36a is provided at the right end of the front guide rail 36 in the left-right direction, and a left-end protrusion 36b is provided at the left end. The right-end protrusion 36a and the left-end protrusion 36b are walls against which the linear cam 124 abuts. The reciprocating movement range of the carriage 31 is the range in which the carriage 31 reciprocates left and right. The reciprocating movement range of the carriage 31 includes the image recording range in which an image is recorded by the recording head 30. The carriage 31 moves both to the right of the image recording range and to the left of the image recording range. In other words, the reciprocating movement range extends on both sides of the image recording range, with the right-end protrusion 36a defining the right end of the reciprocating movement range of the carriage 31 and the left-end protrusion 36b defining the left end of the reciprocating movement range of the carriage 31. As described above, as an initial operation, the carriage 31 moves to the left end of the reciprocating movement range to determine the zero point of the pulse count of the linear encoder 59, and then moves in the opposite direction to control the carriage position by the pulse count of the linear encoder 59.

[0076] When the carriage 31 approaches the right end of its reciprocating range, the right end of the rectilinear cam 124 abuts against the right-end protrusion 36a. If the carriage 31 moves further to the right in this state, the first valve 121 and the second valve 122 move to the right together with the carriage, but the rectilinear cam 124 is blocked by the right-end protrusion 36a and cannot move. As a result, the rectilinear cam 124 is displaced to the left relative to the first valve 121 and the second valve 122.

[0077] Specifically, when the recording head 30 is in the second state, if the carriage 31 is stopped at a position where the right end of the linear cam 124 just abuts the right-end protrusion 36a (FIG. 31A), the linear cam 124 does not displace relative to the recording head 30. Therefore, the first valve arm 121b is maintained at the first height H1, and the second valve arm 122b is maintained at the second height H2, so the recording head 30 is maintained in the second state (FIG. 31B). At this time, the distance from the right end of the carriage 31 to the right end of its reciprocating range is D1. When the purge mechanism 42 is caused to perform a purge suction operation in the second state, all of the nozzles 40 on the nozzle surface 41 are covered with the caps 43, and a negative pressure is applied to the space covered by the caps 43, causing ink to flow into the manifold 103 via the second air trap chamber 102.

[0078] When the carriage 31 is further moved to the right, the recording head 30 transitions from the second state to the first state due to the shape of the upper surface of the linear cam 124, as shown in FIG. 32(B). When the carriage 31 is stopped at this position, the recording head 30 is maintained in the first state. At this time, the distance from the right end of the carriage 31 to the right end of its reciprocating movement range is D2 (FIG. 32(A)). Distance D2 is shorter than distance D1. When the purge mechanism 42 is caused to perform a purge suction operation in the second state, a purge suction operation is performed in which ink flows into the manifold 103 via the first air trap chamber 101. Even when the recording head 30 moves a distance (D1-D2) relative to the cap 43, the cap 43 is large enough to cover all of the nozzles 40 on the nozzle surface 41.

[0079] When the carriage 31 is moved further to the right, the right end of the carriage 31 reaches the right end of its reciprocating movement range, as shown in FIG. 33(A). The recording head 30 transitions from the first state to the third state (FIG. 33(B)). That is, this is a state in which ink can flow into the manifold 103 from both the first air trap chamber 101 and the second air trap chamber 102, allowing an image to be recorded. In this state, when the carriage 31 is moved to the left, the linear cam 124 moves to the left together with the carriage 31 due to friction with the valve holder 123.

[0080] In the opposite direction to the above, when the carriage 31 approaches the left end of its reciprocating movement range, the left end of the rectilinear cam 124 abuts against the left end protrusion 36b (FIG. 34(A)). If the carriage 31 moves further to the left in this state, the first valve 121 and the second valve 122 move to the left together with the carriage, but the rectilinear cam 124 is blocked by the left end protrusion 36b and cannot move. As a result, the rectilinear cam 124 is displaced to the right relative to the first valve 121 and the second valve 122. Note that a purge mechanism 42 is provided at the right end of the reciprocating movement range of the carriage 31, but no purge mechanism 42 is provided at the left end. Therefore, although the state of the recording head 30 is changed, the purge suction operation is not performed.

[0081] Specifically, when the recording head 30 is in the third state, stopping the carriage 31 at a position where the left end of the linear cam 124 abuts the left-end protrusion 36b maintains the recording head 30 in the third state (FIG. 34B). At this time, the distance from the left end of the carriage 31 to the left end of its reciprocating range is D3. To continue recording an image, the carriage 31 does not move further left from this position but turns back to the right. In this way, the recording head 30 is maintained in the third state, allowing ink to be supplied to the manifold 103 from both the first air trap chamber 101 and the second air trap chamber 102. On the other hand, to perform a purge suction operation for the nozzles 40, the carriage 31 is moved further left.

[0082] When the carriage 31 is further moved to the left, the recording head 30 transitions from the third state to the first state due to the shape of the top surface of the linear cam 124, as shown in FIG. 35(B). At this time, the distance from the left end of the carriage 31 to the left end of the reciprocating movement range is D4 (FIG. 35(A)). When the carriage 31 is further moved to the left, the carriage 31 reaches the left end of the reciprocating movement range, as shown in FIG. 36(A). The recording head 30 transitions from the first state to the second state (FIG. 36(B)). When the carriage 31 is moved toward the right end of the reciprocating movement range in this state, the linear cam 124 abuts against the right-end protrusion 36a, as described above, and the carriage 31 is then moved stepwise to the right, thereby performing the purge suction operation.

[0083] (2) In the above modification, the first height H1 in the first region 124a of the contact surface (upper surface) of the rectilinear cam 124 is the same as the first height H1 in the second region 124b, and the second height H2 in the first region 124a is the same as the second height H2 in the second region 124b. However, the first height H1 may be different between the first region 124a and the second region 124b. The first height H2 may also be different between the first region 124a and the second region 124b.

[0084] (3) In the above embodiment, the first direction Da, the second direction Db, and the third direction Dc, which are the locations at which the first cam portion 134a and the second cam portion 134b of the rotating cam 134 come into contact with the first valve arm portion 131b and the second valve arm portion 132b to open and close the first valve 131 and the second valve 132, are offset by 120 degrees from the center of rotation, but the intervals may be other than 120 degrees. Furthermore, the first cam portion 134a and the second cam portion 134b may come into contact with the first valve arm portion 131b and the second valve arm portion 132b in four or more directions to open and close the first valve 131 and the second valve 132.

[0085] (4) In the above embodiment, the rotating cam 134 is rotationally driven by the rotational driving force of the conveying motor 29. However, instead of this, a mechanism for converting linear motion into rotational motion may be used to convert the linear motion of the carriage 31 approaching the right-end protrusion 36a and the left-end protrusion 36b into rotational motion of the rotating cam 134. Even in this case, the same effects as in the above embodiment can be obtained.

[0086] (5) In the above embodiment, purging is performed by a suction operation. However, purging may be performed by an ink discharge operation instead. Specifically, the purge mechanism 42 first tightly fits the cap 43 to the nozzle surface 41. Next, ink is supplied from the ink cartridge through the ink tube. This ink flushes out air bubbles and foreign matter and discharges them from the nozzles 40. The discharged ink passes through the ink discharge tube 52 and is discharged into a waste liquid tank (not shown). This method can also achieve the same effects as the above embodiment. [Explanation of symbols]

[0087] 10...Multifunction device 11 Printer section 15...Paper feed section 25 Paper feed roller 28...Paper feed shaft 29. Conveyor motor 30 Recording head 31. Carriage 32 Carriage motor 33 Drive transmission mechanism 35, 36 Guide rail 36a... Right end protrusion (wall) 36b...Left end protrusion (wall) 40 Nozzle 41 Nozzle surface 42 Purge mechanism 43···Cap 44 Lift-up mechanism 49. Conveyor shaft 50 Maintenance Unit 51 Pump mechanism (tube pump) 52 Ink discharge tube 53 Rotary encoder 55 Optical sensor 56a...1st position 56b...2nd position 57 Encoder Strip 58 Readhead 59 Linear Encoder 61 Motor gear 62 Roller gear 63 Drive gear 64...1st switching mechanism 65 Driven gear 69... First moving gear 70...Second moving gear 100 Supply channel 100a···First flow path 100b Second flow path 101... First air trap chamber 101a...1st opening 102 Second air trap chamber 103 Manifold 104 Ink supply hole (supply hole) 105...Second opening 108···Exhaust port 120···Straight cam mechanism 121, 131... First valve 121a, 131a...1st valve stem part 121b, 131b...1st valve arm 121c, 131c...1st valve head 122, 132... Second valve 122a, 132a...2nd valve stem part 122b, 132b...Second valve arm 123, 133... Valve holder 124···Straight cam (slide cam) 121d···First coil spring 122d...Second coil spring 127, 137... Rubber sheet 130 Rotating cam mechanism 133a... First cylindrical part 133b... Second cylindrical part 134 Rotating cam 134a···First cam part 134b Second cam part 134c Rotating shaft 134d···Winged gear 140 Transmission cutoff mechanism 142 Second gear (reduction gear) 144 Planetary gear mechanism (switching mechanism) 144a···Sun Gear 144b Planetary gear 144c···Planet carrier 144d Planetary stopper 146 Pump drive gear

Claims

1. A liquid ejection device having a head, a first valve, a second valve, and a cam mechanism, The above head is a plurality of nozzles opening on a nozzle surface; a manifold communicating with the plurality of nozzles; a first air trap chamber communicating with the first end of the manifold and extending upward from the first end; a second air trap chamber communicating with the second end of the manifold and extending upward from the second end; a supply flow path communicating with the first air trap chamber and the second air trap chamber, the first valve opens and closes a first flow path in the supply flow path that is connected to the first air trap chamber; the second valve opens and closes a second flow path in the supply flow path that is connected to the second air trap chamber; The cam mechanism selectively changes the state of a liquid ejection device to either a first state in which the first valve closes the first flow path and the second valve opens the second flow path, or a second state in which the first valve opens the first flow path and the second valve closes the second flow path.

2. the first flow path includes a first opening at an upper end of the first air trap chamber; the first valve opens and closes the first opening; the second flow path includes a second opening located between an upper end of the first air trap chamber and an upper end of the second air trap chamber, The liquid ejection device according to claim 1 , wherein the second valve opens and closes the second opening.

3. 2. The liquid ejection device according to claim 1, wherein the first volume of the first air trap chamber and the second volume of the second air trap chamber are approximately the same.

4. The above head is An exhaust port; an exhaust flow path that connects an upper end of the second air trap chamber with the exhaust port, the supply flow path has a supply hole through which liquid is supplied, the first air trap chamber is located upstream of the second air trap chamber in a flow direction in which the liquid flows in the supply flow channel, The liquid ejection device according to claim 3 , wherein the supply flow path communicates with the exhaust flow path.

5. The cam mechanism is A motor; A rotating cam, a transmission mechanism that transmits the driving force of the motor to the rotating cam, 2. The liquid ejection device according to claim 1, wherein the transmission mechanism includes a reduction gear.

6. The pump mechanism is further provided, and is driven by the forward rotation of the motor.

6. The liquid ejection device according to claim 5, wherein the transmission mechanism further comprises a switching mechanism that does not transmit forward rotation of the motor to the rotating cam, but transmits reverse rotation of the motor to the rotating cam.

7. the pump mechanism is a tube pump, The forward rotation of the motor generates suction pressure, 7. The liquid ejection device according to claim 6, wherein the inside of the tube is opened to the atmosphere by the reverse rotation of the motor.

8. 8. The liquid ejection device according to claim 7, wherein the switching mechanism is a planetary gear that moves in contact with and out of contact with a gear that drives the rotating cam.

9. 9. The liquid discharge device according to claim 8, wherein the planetary gear moves in a direction to mesh with the gear when the motor rotates in the reverse direction, and meshes with the gear after the pump mechanism opens the inside of the tube to the atmosphere.

10. The apparatus further includes a carriage that carries and moves the head, the first valve, the second valve, and the cam mechanism, the cam mechanism is a slide cam, The liquid ejection device described in claim 1, wherein the slide cam slides to one of the first state, the second state, and a third state in which the first valve opens the first flow path and the second valve opens the second flow path by abutting against a wall due to movement of the carriage.

Images