JP5028938B2 - ink cartridge - Google Patents

Description

  The present invention relates to an ink cartridge used by being mounted on an ink jet recording apparatus, and more particularly to an ink flow path in an ink tank.

  2. Description of the Related Art Conventionally, inkjet recording apparatuses that record images on recording paper (recording medium) using ink are widely known (see Patent Documents 1 to 4). The ink jet recording apparatus includes an ink jet recording head. The recording head selectively ejects ink supplied to the recording head from the nozzles toward the recording paper. As a result, an image formed of ink is recorded on the recording paper. The ink jet recording apparatus is provided with an ink cartridge including an ink tank. Ink is supplied from the ink tank of the ink cartridge to the recording head.

  This type of ink jet recording apparatus includes an ink supply mechanism that not only supplies ink from the ink cartridge to the recording head but also returns ink supplied to the recording head to the ink tank and supplies ink to the recording head again. This is disclosed in Patent Document 1. According to the ink supply mechanism, when ink is returned from the recording head to the ink tank, bubbles accumulated in the ink path between the recording head and the ink cartridge are drawn into the ink tank together with the ink. At this time, bubbles and ink are separated in the ink tank. Thereby, bubbles accumulated in the ink path are removed.

  Further, as described in Patent Document 2, an ink jet recording apparatus that detects the amount of ink in an ink tank by an arm member (shutter mechanism in Patent Document 2) that is swingably provided in the ink tank is known. The arm member swings according to the amount of ink stored using buoyancy in the ink. The arm member swings between a detection position and a non-detection position by a detection means such as an optical sensor, whereby the ink storage amount is detected.

JP 2000-85141 A JP 2005-254734 A JP-A-5-138893 JP-A-7-89081

  By the way, when air bubbles are included in the ink returned from the recording head to the ink tank, the air bubbles rise in the ink in the ink tank by buoyancy. In the ascending process, the bubbles may pass near the arm member provided in the ink tank. At this time, bubbles may adhere to the arm member. If air bubbles adhere to the arm member, there is a problem that the arm member erroneously swings due to the buoyancy of the adhering air bubbles, resulting in erroneous detection of a detection means such as an optical sensor.

  Therefore, the present invention has been made in view of the above problems, and the object of the present invention is to prevent the adhesion of bubbles that cause the rocking failure of the arm member and reduce the false detection of the optical sensor. An object of the present invention is to provide an ink cartridge capable of improving the detection accuracy of the ink storage amount.

  (1) The present invention is an ink cartridge used by being mounted on an ink jet recording apparatus. The ink cartridge of the present invention is provided on an ink tank having an ink storage chamber for storing ink and forming an air layer in an upper layer portion, a wall surface of the ink tank, and the outflow of ink from the ink tank to the outside, and A communication hole that allows the ink tank to flow into the ink tank from the outside and communicates with the outside; an arm member that is swingably provided in the ink storage chamber and detects the amount of ink stored; The ink flowing into the ink tank through the communication hole is guided to the upper layer part by bypassing the arm member through a space separated from the space in the ink storage chamber in which the arm member is provided. 1 ink flow path and the ink stored in the ink storage chamber in a state where ink is not flowing into the ink tank from the outside, A second ink channel that leads to the communication hole through a space separated from the first ink channel, and a second ink channel that is provided in the second ink channel, and the ink reservoir chamber has a positive pressure with respect to the outside. And a second check valve that is opened on the condition that the ink storage chamber is closed on the condition that the ink storage chamber has a negative pressure with respect to the outside.

  The ink tank has an ink storage chamber. Ink used in the ink jet recording apparatus is stored in the ink storage chamber. An air layer is formed in the upper layer portion of the ink storage chamber. On the wall surface of the ink tank, a communication hole that communicates the ink storage chamber with the outside is provided. Through this communication hole, ink is circulated between the ink tank and the recording head. An arm member is provided in the ink tank so as to be able to swing according to the amount of ink stored. By detecting the swing position of the arm member with an external sensor, the amount of ink stored is detected.

  The ink tank is provided with a first ink channel and a second ink channel. The ink flowing into the ink tank through the communication hole is guided from the communication hole to the upper layer of the ink tank through the first ink flow path. On the other hand, the ink flowing out of the ink tank through the communication hole is guided to the communication hole from the lower layer portion of the ink tank through the second ink flow path.

  The first ink flow path is provided so as to bypass the arm member. Accordingly, the ink passing through the first ink flow path flows toward the upper layer portion so as to avoid the arm member. Thereby, the bubbles contained in the ink do not adhere to the arm member.

  Further, the back flow of ink in the second ink flow path is prevented.

  (2) The ink cartridge of the present invention is provided in the first ink flow path, and is opened on the condition that the ink storage chamber has a negative pressure with respect to the outside. A first check valve that is closed on condition that the pressure is positive is further provided.

Thereby, the backflow of the ink in the first ink flow path is prevented .

(3) The upper layer portion is a region where there is an air layer formed when a predetermined amount of ink is injected into the ink storage chamber.

  The ink cartridge distributed in the market includes an ink tank in which a predetermined amount (quantitative amount) of ink is stored. When a certain amount of ink is injected into the ink tank, an air layer is formed in the upper layer portion of the ink tank. If the first ink flow path guides ink to the region where the air layer formed as described above exists, the ink is guided to the upper layer portion without passing through the arm member.

(4) The first ink flow path includes a first vertical flow path extending vertically upward along the wall surface from the communication hole, and a horizontal direction along the wall surface from the end of the first vertical flow path. And a second vertical flow path extending vertically upward along the wall surface from the end of the horizontal flow path to reach the upper layer portion.

  Thereby, the first ink flow path is specifically realized.

(5) The ink cartridge of the present invention is provided in the first ink flow path, and is opened on the condition that the ink storage chamber has a negative pressure with respect to the outside. A first check valve that is closed on condition that the pressure is positive is further provided. The first ink channel extends from the communication hole vertically upward along the wall surface, and extends horizontally from the terminal end of the first vertical channel along the wall surface. And a second vertical flow path extending vertically upward along the wall surface from the end of the horizontal flow path to reach the upper layer portion. The first check valve is provided in the horizontal flow path.

  With this configuration, the first check valve can be easily disposed in the first ink flow path.

(6) The horizontal flow path is provided with a buffer chamber for buffering ink flow.

  Thereby, for example, even when the ink flows into the ink tank vigorously, the ink flow in the first ink flow path is buffered in the buffer chamber, so that no ink is ejected to the air layer.

  According to the ink cartridge of the present invention, since bubbles contained in the ink do not adhere to the arm member, it is possible to prevent unintentional swinging of the arm member and erroneous detection of the optical sensor caused by the bubbles attached to the arm member. . As a result, the detection accuracy of the ink storage amount is improved.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. Note that the following embodiment is merely an example of the present invention, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.

  First, with reference to FIG. 1 and FIG. 2, a schematic configuration and operation of an ink jet recording apparatus 10 to which an ink cartridge 50 and an ink supply apparatus 11 according to an embodiment of the present invention are applied will be described. FIG. 1 is a schematic cross-sectional view showing the internal mechanism of the inkjet recording apparatus 10, and FIG. 2 is an enlarged view of a main part showing the recording unit 14 of FIG. 1 in detail. 2A shows a state in which the opening 42 of the valve 37 is closed, and FIG. 2B shows a state in which the opening 42 of the valve 37 is opened.

  The ink jet recording apparatus 10 uses five colors of ink, that is, cyan (C), magenta (M), yellow (Y), photo black (PBk) that is dye ink, and black (Bk) that is pigment ink. Thus, a color image or a monochrome image is recorded on a recording sheet (an example of a recording medium). As shown in FIG. 1, the ink jet recording apparatus 10 roughly includes a paper feeding device 12, a transport device 13, a recording unit 14, and an ink supply device 11. A paper feed tray 16 is provided on the bottom surface of the ink jet recording apparatus 10. The recording paper loaded on the paper feed tray 16 is fed to the transport path 18 by the paper feed device 12.

  The conveyance path 18 is formed in a U-shape that is substantially horizontal in a sectional view. A transport device 13 is disposed in the transport path 18. The transport device 13 includes a transport roller pair 13A and a paper discharge roller pair 13B. The conveyance roller pair 13A is provided on the upstream side in the conveyance direction of the recording unit 14 (on the right side in FIG. 1). The paper discharge roller pair 13B is provided on the downstream side in the transport direction of the recording unit 14 (left side in FIG. 1).

  The recording paper fed to the conveyance path 18 is conveyed toward the platen 19 by the conveyance roller pair 13A. A recording unit 14 is disposed above the platen 19. The recording unit 14 records an image on a recording sheet that passes over the platen 19. When the leading edge of the recording paper reaches the paper discharge roller pair 13B, the paper discharge roller pair 13B pinches the leading edge of the recording paper and starts conveying the recording paper. Until the trailing edge of the recording sheet passes the conveying roller pair 13A, the recording sheet is conveyed by both the conveying roller pair 13A and the discharge roller pair 13B. After the trailing edge of the recording sheet passes through the conveyance roller pair 13A, the recording sheet is conveyed only by the discharge roller pair 13B. A paper discharge tray 17 is provided on the most downstream side of the transport path 18. The recording sheet on which the image is recorded is discharged to the discharge tray 17 by the discharge roller pair 13B.

  The recording unit 14 includes a carriage 30 that also serves as a housing, a sub tank 21, a head control board 27, and a recording head 26. The carriage 30 is supported by a support rail (not shown) so as to be slidable in a direction perpendicular to the paper surface of FIG. The sub tank 21 stores ink supplied to the recording head 26. The sub tank 21 is provided corresponding to the color of ink used in the inkjet recording apparatus 10. Therefore, in the present embodiment, the carriage 30 is provided with five sub tanks 21.

  The recording head 26 includes a nozzle 28. Based on the image signal input to the head control board 27, ink is ejected from the nozzles 28 toward the recording paper. The ink jet recording apparatus 10 is provided with a main control unit (not shown) that comprehensively controls the apparatus, and the image signal is output from the main control unit and input to the head control board 27. The

  As shown in FIG. 2, a tube joint 33 is provided on the side surface of the carriage 30. An ink tube 32 (an example of the tube of the present invention) is connected to the tube joint 33. The tube joint 33 and the ink tube 32 are provided corresponding to the color of ink used in the inkjet recording apparatus 10. Therefore, in this embodiment, since five colors of ink are used, five tube joints 33 and five ink tubes 32 are provided. Inside the carriage 30, a flow path 34 extending from the tube joint 33 to the bottom surface of the sub tank 21 is formed.

  The carriage 30 is provided with a valve 37. The opening 42 is opened and closed by switching the valve 37. As shown in FIG. 2, the valve 37 is a piston-type valve including a cylinder 39 communicating with the sub tank 21, a coil spring 41, and a piston 40. The coil spring 41 is accommodated in the cylinder 39. Further, the piston 40 is accommodated in the cylinder 39 in a state where the coil spring 41 is contracted. Therefore, the piston 40 is always urged in one direction (downward with respect to the paper surface of FIG. 2) by the coil spring 41. A rod 43 for transmitting external force is connected to the piston 40. The rod 43 is inserted through an opening 42 provided in the cylinder 39 and extends to the outside. As long as no external force is applied to the rod 43, the opening 42 is closed by the piston 40 as shown in FIG.

  As shown in FIG. 2B, when an external force is applied from the rod 43 to the piston 40, the piston 40 moves in the cylinder 39 against the urging force of the coil spring 41. Specifically, in FIG. 2, when the rod 43 is pressed upward from below, the piston 40 is pushed up against the urging force of the coil spring 41. At this time, the opening 42 is opened. Thereby, the inside of the sub tank 21 and the atmosphere communicate with each other through the opening 42 and the cylinder 39. In other words, the inside of the sub tank 21 communicates with the atmosphere. The opening 42 is opened when ink flows into and out of the sub tank 21 through the ink tube 32. On the other hand, when the ink jet recording apparatus 10 is not in operation, that is, in a so-called standby state, the opening 42 is closed to prevent ink from evaporating.

  As shown in FIG. 1, the ink supply device 11 includes a cartridge mounting unit 200, an ink cartridge 50, an ink tube 32, and a sub tank 21. The ink cartridge 50 is mounted on the cartridge mounting unit 200. In the present embodiment, the ink cartridge 50 is configured to be detachable from the cartridge mounting portion 200. The ink cartridge 50 includes a main tank 70. The main tank 70 and the sub tank 21 are both containers for storing ink. The main tank 70 and the sub tank 21 are connected by an ink tube 32. In the present embodiment, one ink tube 32 is provided between the main tank 70 and the sub tank 21 according to the color of the ink used in the ink jet recording apparatus 10. Through the ink tube 32, the ink flows in both directions between the main tank 70 and the sub tank 21. The ink tube 32 is made of synthetic resin and has flexibility. Therefore, even if the carriage 30 slides, the ink tube 32 follows the carriage 30.

  In the present embodiment, as described above, since the ink supply device 11 is provided in the ink jet recording apparatus 10, ink can be circulated bidirectionally between the main tank 70 and the sub tank 21. Therefore, by returning the ink from the sub tank 21 to the main tank 70 by the ink supply device 11, the bubbles in the sub tank 21 and the ink tube 32 can be separated from the ink in the main tank 70 and removed. Further, by supplying ink from the main tank 70 to the sub tank 21, the ink in the sub tank 21 is replaced with the ink stored in the main tank 70. Thereby, the ink of the main tank 70 and the ink of the sub tank 21 are mixed, and the ink viscosity becomes uniform. Below, each element which comprises the ink supply apparatus 11 which concerns on this embodiment is demonstrated in detail.

  First, an external configuration and an internal configuration of the ink cartridge 50 will be described with reference to FIGS. FIG. 3 is a perspective view showing the external configuration of the ink cartridge 50. FIG. 3A shows the assembled state of the case 52, and FIG. 3B shows the case 52 disassembled. Indicates the state. FIG. 4 is a perspective view showing an external configuration of the ink cartridge 50. FIG. 5 is a perspective view showing the internal configuration of the ink cartridge 50. FIG. 6 is a side view as seen from the direction of the arrow VI in FIG. 5 and shows the internal configuration of the ink cartridge 50. 7 is a cross-sectional view taken along section line VII-VII in FIG. FIG. 8 is an exploded cross-sectional view of the ink cartridge 50. FIG. 9 is a partial cross-sectional view taken along section line IX-IX in FIG. In FIG. 8, the case 52 is omitted.

  As shown in FIGS. 3 and 4, the ink cartridge 50 includes a case 52. Each element constituting the ink cartridge 50 is accommodated in the case 52. The case 52 is thin in the width direction (Y-axis direction in the figure), is long in the height direction (vertical direction, Z-axis direction in the figure), and the depth direction (X-axis direction in the figure) is higher than the height direction. Is formed in a substantially longer rectangular parallelepiped shape. Accordingly, the appearance of the ink cartridge 50 has a substantially rectangular parallelepiped shape. With the ink cartridge 50 having such a shape, the planar arrangement space of the ink cartridge 50 in the cartridge mounting portion 200 (see FIG. 17) can be reduced. In particular, when the inkjet recording apparatus 10 is equipped with a plurality of ink cartridges 50, the above shape is suitable. Of course, the ink cartridge 50 is not limited to the above shape. Note that the X-axis direction in the drawing coincides with the mounting direction of the ink cartridge 50 with respect to the cartridge mounting portion 200. In addition, a plane formed by the X axis and the Y axis in the drawing (hereinafter referred to as “XY plane”) is a horizontal plane. The ink cartridge 50 is mounted on the cartridge mounting unit 200 in the posture shown in FIG. 3A, that is, the posture standing on the XY plane.

  As shown in FIG. 3B, the case 52 includes a first case member 53 and a second case member 54. The case 52 can be separated into a first case member 53 and a second case member 54 along the longitudinal direction of the ink cartridge 50 (X-axis direction and Z-axis direction in the drawing). The first case member 53 and the second case member 54 are formed in substantially the same shape. The first case member 53 and the second case member 54 are both made of synthetic resin and obtained by, for example, injection molding.

  The case 52 is provided with three openings 56, 57 and 58. The opening 56 is provided from the upper surface 59 of the case 52 to the back surface 60 (surface on the front side in the mounting direction of the ink cartridge 50). The opening 56 is formed by a notch 61 formed in each of the first case member 53 and the second case member 54. A rack gear 185 (see FIG. 6) described later is inserted through the opening 56. The opening 57 is provided in the lower part of the back surface 60 (see FIG. 4). The opening 57 is formed by a semicircular cutout (not shown) formed in each of the first case member 53 and the second case member 54. An ink supply valve 130 (to be described later) is fitted into the opening 57 from the inside of the case 52 and exposed to the outside. The opening 58 is provided in the vicinity of the middle between the opening 56 and the opening 57 on the back surface 60 (see FIG. 4). The opening 58 is formed by a rectangular notch 62 (see FIG. 4) formed in each of the first case member 53 and the second case member 54. From the opening 58, a detection unit 75 (see FIG. 6) described later is exposed to the outside.

  As shown in FIGS. 5 to 7, a main tank 70, a pump 170, an air communication valve 110, and an ink supply valve 130 are disposed inside the case 52. In this embodiment, the main tank 70, the pump 170, the atmosphere communication valve 110, and the ink supply valve 130 are all made of synthetic resin.

  The main tank 70 is almost entirely covered with a case 52. Accordingly, the main tank 70 is thin in the width direction (Y-axis direction) corresponding to the case 52, long in the height direction (vertical direction, Z-axis direction), and long in the depth direction (mounting direction, X-axis direction). Presents a shape. The main tank 70 stores ink supplied to the sub tank 21. The main tank 70 includes a translucent frame 71 and a transparent film 81 (see FIG. 9) welded to both side surfaces of the frame 71. The frame 71 defines an ink chamber 73 in which ink is stored. Although the film 81 originally appears in the side view of FIG. 6, the film 81 is omitted in the figure.

  As shown in FIGS. 5 to 8, the main tank 70 has an ink injection portion 72. The ink injection part 72 is formed integrally with the frame 71. The ink injection part 72 is formed in a substantially cylindrical shape as shown in FIG. An inlet 82 is provided on the front surface 80 of the main tank 70. The ink injection part 72 extends from the injection port 82 in the X-axis direction in the figure. A predetermined amount (in this embodiment, approximately 80% of the ink chamber 73 in this embodiment) of ink is injected into the ink chamber 73 of the main tank 70 from the inlet 82 through the ink injection portion 72. As a result, an air layer 83 (corresponding to the air layer of the present invention, see FIG. 10) is formed in the upper layer portion of the main tank 70. FIG. 10 shows a state where a predetermined amount of ink is injected into the ink chamber 73. The ink injection portion 72 is sealed by press-fitting a resin plug member from the injection port 82 after ink is injected. Therefore, the ink chamber 73 is substantially sealed after ink injection. Therefore, the air layer 83 is airtight. Thereby, ink or air does not leak out from the injection port 82.

  As shown in FIGS. 7 and 8, a circular opening 84 is provided in the upper portion of the front surface 80 of the main tank 70. A cylindrical valve housing chamber 85 is formed in the main tank 70 continuously with the opening 84. The atmospheric communication valve 110 is accommodated in the valve accommodating chamber 85 (see FIG. 7). The valve storage chamber 85 extends from the opening 84 to the inside of the main tank 70 along the X-axis direction in the drawing. A hole 100 communicating with the ink chamber 73 is formed in the inner surface of the valve storage chamber 85. Specifically, the hole 100 communicates with the upper layer portion of the ink chamber 73. That is, the valve storage chamber 85 communicates with the upper layer portion of the ink chamber 73 through the hole 100. More specifically, the valve storage chamber 85 communicates with an air layer 83 (see FIG. 10) formed in the upper layer portion of the ink chamber 73 through the hole 100. A rod 117 (see FIG. 11) of the atmospheric communication valve 110 described later is inserted into the hole 100. The hole 100 is formed larger than the diameter of the rod 117. Therefore, even if the rod 117 is inserted into the hole 100, the hole 100 is not blocked. Accordingly, the air flow between the valve storage chamber 85 and the ink chamber 73 is not obstructed in a state where the rod 117 is inserted into the hole 100. Further, as shown in FIG. 11, the rod 117 has a substantially cross-shaped cross section in a direction orthogonal to the longitudinal direction, and therefore air is introduced into the V-shaped valley portion 117 </ b> B (see FIG. 11) of the rod 117. The flow path is formed. Therefore, even when the rod 117 is inserted into the hole 100, the air smoothly flows through the valley portion 117B. In addition, a hole 101 communicating with the outside of the main tank 70 is formed on the inner peripheral surface of the valve storage chamber 85. A spatial flow path formed between the hole 101 and the hole 100 is connected or blocked by the atmospheric communication valve 110.

  As shown in FIGS. 7 to 9, a circular opening 87 is provided at the lower part of the back surface 79 (the front surface of the main tank 70 in the mounting direction) of the main tank 70. A cylindrical valve housing chamber 88 is formed continuously with the opening 87. The ink supply valve 130 is accommodated in the valve accommodating chamber 88 (see FIG. 7). The valve storage chamber 88 extends from the opening 87 to the inside of the main tank 70 along the X-axis direction in the drawing. A hole 89 is formed in the inner surface of the valve storage chamber 88. The valve storage chamber 88 communicates with the ink chamber 73 through a hole 89.

  As shown in FIGS. 7 to 9, the main tank 70 has a flow path 91 (corresponding to the second ink flow path of the present invention) extending from the ink chamber 73 to the valve storage chamber 88. The channel 91 extends from the lower layer of the ink chamber 73 through the hole 89 in the X-axis direction in the drawing and reaches the valve housing chamber 88. That is, the boundary portion between the hole 89 and the valve storage chamber 88 corresponds to the end portion on the communication hole side of the second ink flow path of the present invention. The channel 91 is provided with a check valve 95 (corresponding to the second check valve of the present invention) for opening and closing the hole 89. The check valve 95 is opened when the ink chamber 73 has a positive pressure with respect to the valve storage chamber 88, and conversely, is closed when the ink chamber 73 has a negative pressure with respect to the valve storage chamber 88. To do. Therefore, when the ink chamber 73 is pressurized by, for example, air being sent into the ink chamber 73, the ink chamber 73 has a positive pressure than the valve storage chamber 88. At this time, the check valve 95 is opened and a check valve 95 described later is closed. Accordingly, the ink stored in the ink chamber 73 is guided to the valve storage chamber 88 through the flow path 91.

  As shown in FIGS. 7 to 9, the main tank 70 has a flow path 92 (corresponding to the first ink flow path of the present invention) extending from the valve storage chamber 88 to the ink chamber 73. As shown in FIG. 9, the flow path 92 includes a first vertical flow path 92 </ b> A extending from the valve housing chamber 88 in the Z-axis direction (vertical direction) in the figure, and the end of the first vertical flow path in the figure. A horizontal flow path 92B extending in the Y-axis direction (horizontal direction) and a second vertical flow path extending from the end of the horizontal flow path 92B to the Z-axis direction (vertical direction) in the drawing and reaching the upper layer portion of the ink chamber 73 92C. That is, the boundary portion between the valve storage chamber 88 and the first vertical flow path 92A corresponds to the end portion on the communication hole side of the first ink flow path of the present invention. A buffer chamber 90 described later is disposed in the horizontal flow path 92B. The opening 94 at the end of the flow path 92 is open to an upper layer portion of the ink chamber 73, in other words, an air layer 83 (see FIG. 10) formed in the upper layer portion of the ink chamber 73. The upper side of the flow path 92 is bent vertically after reaching the upper layer of the ink chamber 73 as shown in FIGS. The ink that has flowed into the valve storage chamber 88 from the opening 87 is guided to the air layer 83 through the flow path 92. The flow paths 91 and 92 are both formed by the frame 71 and ribs provided on the frame 71.

  A buffer chamber 90 is provided in the horizontal channel 92 </ b> B of the channel 92. The buffer chamber 90 is disposed immediately above the valve storage chamber 88. The buffer chamber 90 has a function of buffering the flow of ink flowing into the ink tank 70, and the cross-sectional area thereof is larger than the cross-sectional area of the flow path 92. As shown in FIG. 9, the buffer chamber 90 has a cylindrical shape extending in the width direction of the main tank 70, that is, in the Y-axis direction in the drawing.

  The buffer chamber 90 is provided with a check valve 93 (corresponding to the first check valve of the present invention) near the middle in the Y-axis direction in FIG. The check valve 93 is opened when the ink chamber 73 has a negative pressure with respect to the valve storage chamber 88, and conversely, is closed when the ink chamber 73 has a positive pressure with respect to the valve storage chamber 88. To do. Accordingly, when ink flows into the valve storage chamber 88 from the recording head 26 (see FIG. 1) through the ink tube 32, the valve storage chamber 88 becomes more positive than the ink chamber 73. At this time, the check valve 93 is opened and the check valve 95 is closed. Thus, the ink that has flowed into the valve storage chamber 88 is guided to the ink chamber 73 through the flow path 92.

  In the present embodiment, since the check valves 93 and 95 described above are provided, when ink flows into the valve storage chamber 88 from the outside, the ink flows from the valve storage chamber 88 through the buffer chamber 90 to the flow path. It flows upward of 92. In addition, when air is sent into the ink chamber 73, the ink stored in the ink chamber 73 flows from the ink chamber 73 toward the valve storage chamber 88 through the hole 89. Thus, since the check valve 93 is provided in the flow path 92 and the check valve 95 is provided in the flow path 91, in the main tank 70, as indicated by the broken line arrow 86 in FIG. 8, A circulation flow path is formed through which ink flows in one direction.

  Further, the air bubbles drifting in the valve storage chamber 88 rise by its buoyancy and enter the upper buffer chamber 90 through the second vertical flow path 92A. At this time, if the check valve 93 is opened, the bubbles reach the air layer 83 (see FIG. 10) through the horizontal flow path 92B, the check valve 93, and the second vertical flow path 92C. On the other hand, even if the check valve 93 is closed, the air bubbles drifting in the valve storage chamber 88 gather in the buffer chamber 90 and are stopped here. Accordingly, when the ink in the sub tank 21 and the ink tube 32 of the recording head 26 is returned to the main tank 70, even if the returned ink remains in the valve storage chamber 88, bubbles are separated from the ink. Collected in the buffer chamber 90. In other words, bubbles do not remain in the valve storage chamber 88.

  As shown in FIG. 8, a space 96 for mounting the pump 170 is secured on the upper surface 78 of the main tank 70. Around the space 96, mounting seats 98 and 99 for fixing the pump 170 to the space 96 are provided. Specifically, the mounting seat 98 is provided on the frame 71 constituting the wall surface in the back of the valve storage chamber 85 on the front surface 80 side of the main tank 70. The mounting seat 99 is erected on the upper surface 78 on the rear surface 79 side of the main tank 70. These mounting seats 98 and 99 are formed integrally with the frame 71.

  The mounting seat 99 has a hole 102 having a size slightly larger than the outer diameter of the cylinder 171 constituting the pump 170. The hole 102 penetrates in the X-axis direction in the figure. By inserting the cylinder 171 into the hole 102, the rear end of the cylinder 170 is fixed to the mounting seat 99. The tip of the cylinder 171 is fixed to the mounting seat 98. As a result, the pump 170 is integrated with the main tank 70 and securely attached without loosening. The mounting seat 98 is provided with a hole 103 communicating with the ink chamber 73, and the inside of the cylinder 171 communicates with the ink chamber 73 through the hole 103.

  As shown in FIGS. 6 to 8, the main tank 70 includes a detection unit 75. The detection unit 75 is for detecting the remaining amount of ink stored in the ink chamber 73. The detection unit 75 protrudes from the middle of the back surface 79 of the main tank 70 to the outside in the X axis direction. The detection unit 75 is formed integrally with the frame 71. Therefore, the detection unit 75 is made of the same material as the frame 71, that is, a translucent synthetic resin. As will be described later, light is transmitted through the optical sensor 203 (see FIG. 19) in the detection unit 75. In the present embodiment, the detection unit 75 is made of a translucent material, but may be made of any material as long as it has optical transparency (transparency). Therefore, the detection unit 75 may be made completely transparent in order to improve the light transmittance.

  As shown in FIGS. 7 to 9, the detection unit 75 includes a U-shaped cavity 76 in a side view extending in the height direction (Z-axis direction). The cavity 76 is continuous with the ink chamber 73. A shielding portion 157 (an example of the detection element of the present invention) of a sensor arm 150 (an example of the arm member of the present invention) described later enters or leaves the cavity 76. The shielding portion 157 that has entered the hollow portion 76 comes into contact with the support wall 74 that constitutes the bottom surface (lower surface) inside the detection portion 75, and further entry is prevented. On the other hand, as shown in FIG. 7, the shielding portion 157 that has retreated from the cavity portion 76 stops at a predetermined position that is slightly separated from the cavity portion 76.

  The main tank 70 includes a support part 97. The support part 97 supports the below-described sensor arm 150 in a swingable manner. The support part 97 is provided integrally with the frame 71. The support portion 97 is pivotally supported so as to grip the connecting shaft 158 (see FIG. 8) of the sensor arm 150.

  Hereinafter, the sensor arm 150, the atmosphere communication valve 110, the pump 170, and the ink supply valve 130 attached to the main tank 70 will be described in detail with reference to the drawings as appropriate.

  First, the configuration of the sensor arm 150 will be described with reference to FIG. FIG. 8 shows the outer appearance of the sensor arm 150 in detail. The sensor arm 150 is a member for detecting the remaining amount of ink stored in the ink chamber 73. The sensor arm 150 is made of synthetic resin and is obtained by injection molding. As shown in FIG. 8, the sensor arm 150 includes a balance portion 152, a connecting portion 153, and an arm portion 154.

  A connecting shaft 158 is formed in the connecting portion 153. The connecting shaft 158 is pivotally supported by a support portion 97 (see FIG. 8) provided on the frame 71. Thereby, the sensor arm 150 is supported by the support part 97 so that rocking | fluctuation is possible.

  The balance portion 152 extends straight from the connecting portion 153 in a direction orthogonal to the connecting shaft 158. The balance portion 152 is formed so that the average specific gravity is lighter than the specific gravity of the ink. Specifically, the inside of the balance part 152 is hollowed out. Therefore, the balance part 152 plays the role of a buoyancy body in the ink. The balance portion 152 may be made of a material having a specific gravity smaller than that of the arm portion 154 and ink.

  As shown in FIG. 8, the arm portion 154 includes a first arm 155, a second arm 156, and a shielding portion 157. The first arm 155 extends from the connecting portion 153 in a direction that is substantially perpendicular to the balance portion 152 (upward in the drawing of FIG. 8). A second arm 156 is formed continuously from the tip of the first arm 155. The second arm 156 extends from the tip of the first arm 155 in the direction away from the balance portion 152. A shield 157 is formed at the tip of the second arm 156, that is, at the tip of the sensor arm 150.

  In the present embodiment, the arm portion 154 has a weight smaller than that of the balance portion 152. Accordingly, the balance portion 152 is heavier than the arm portion 154 in the air. Therefore, the sensor arm 150 is pulled in the direction of gravity of the balance unit 152 in a state where no ink is contained in the ink chamber 73. As a result, the sensor arm 150 rotates counterclockwise (the direction indicated by the arrow 162 in FIG. 7) about the connecting shaft 158. At this time, the shielding part 157 exits from the cavity part 76 of the detection part 75. In addition, when the lower end of the balance part 152 contacts the bottom surface of the main tank 70, the rotation of the sensor arm 150 is stopped. At this time, as shown in FIG. 7, the shielding unit 157 stops at a predetermined position where the shielding unit 157 has left the detection unit 75.

  On the other hand, as shown in FIG. 10, in a state where the predetermined amount of ink is injected into the ink chamber 73, the balance unit 152 is immersed in the ink. At this time, a buoyancy greater than that of the arm portion 154 is generated in the balance portion 152. Due to this buoyancy, the balance of the weight of the balance portion 152 and the arm portion 154 is reversed. That is, in the ink, the force acting in the gravity direction of the balance portion 152 is smaller than the force acting in the weight direction of the arm portion 154. Therefore, the sensor arm 150 is pulled in the direction of gravity of the arm portion 154. As a result, the sensor arm 150 rotates clockwise (in the direction indicated by the arrow 163 in FIG. 10) about the connecting shaft 158. At this time, the shield 157 enters the cavity 76 of the detector 75. In addition, when the lower end of the shielding part 157 contacts the support wall 74, the rotation of the sensor arm 150 is stopped and the posture is maintained.

  Next, a detailed configuration of the atmosphere communication valve 110 will be described with reference to FIGS. 11 and 12. FIG. 11 is an exploded perspective view showing components of the atmosphere communication valve 110. FIG. FIG. 12 is a partially enlarged view showing a cross-sectional structure of the atmosphere communication valve 110. FIG. 12A shows a state where the piston 116 is stationary at the position P1, and FIG. 12B shows a state where the piston 116 is at the position P2. Shows a stationary state.

  The atmosphere communication valve 110 is a valve for opening and closing the hole 101 to open the air layer 83 (see FIG. 10) formed in the ink chamber 73 of the main tank 70 to the atmosphere. As shown in FIGS. 11 and 12, the atmosphere communication valve 110 includes a cap 111, a coil spring 112, a piston valve 113, and a valve seat 114. The atmospheric communication valve 110 is configured by sequentially connecting these elements (cap 111, coil spring 112, piston valve 113, valve seat 114) in that order. Among the above elements, the coil spring 112, the piston valve 113, and the valve seat 114 are accommodated in the valve accommodating chamber 85 (see FIG. 8), and the cap 111 is attached to the periphery of the opening 84 (see FIG. 8).

  The coil spring 112 elastically biases the piston valve 113 housed in the valve housing chamber 85 in the depth direction of the valve housing chamber 85 (X-axis direction in FIG. 8). The coil spring 112 is made of resin or metal. The coil spring 112 is accommodated in the valve accommodating chamber 85 in a previously contracted state. Therefore, the coil spring 112 always generates an urging force in the extending direction in the valve accommodating chamber 85. In the present embodiment, the coil spring 112 is used. However, the present invention is not limited to the coil spring, and instead of the coil spring 112, for example, a leaf spring may be used. Further, any material, shape, and configuration can be substituted for the coil spring 112 as long as it is a member that elastically biases the valve housing chamber 85 in the depth direction. Of course, a later-described spring unit 134 (see FIG. 14) applied to the ink supply valve 130 may be used.

  The cap 111 has a back wall 119 that forms the back surface, and a cylindrical side wall 118 that stands from the periphery of the back wall 119 and forms a side surface. The back wall 119 also serves as a spring seat that receives the coil spring 112. A plurality (two in this embodiment) of long holes 120 are formed in the side wall 118. A projection piece (not shown) is provided on the periphery of the opening 84 (see FIG. 8), and this projection piece is inserted into the long hole 120. Thereby, the cap 111 is fixed to the periphery of the opening 84.

  The piston valve 113 includes a cylindrical piston 116 and a rod 117 formed integrally with the piston 116. The piston 116 also serves as a spring seat that receives the coil spring 112. The piston 116 is elastically biased in the X-axis direction in the drawing by the coil spring 112. The piston valve 113 is slidably provided on the inner peripheral surface of the valve storage chamber 85. An O-ring 121 is provided between the outer peripheral surface of the piston 116 and the inner peripheral surface of the valve storage chamber 85. Specifically, an O-ring 121 is fitted in a groove 122 formed on the outer peripheral surface of the piston 116. Accordingly, the piston valve 113 slides in the valve housing chamber 85 in a state where a gap formed between the piston valve 113 and the inner peripheral surface of the valve housing chamber 85 is sealed. Instead of the O-ring 121, an elastic body such as rubber may be fitted into the groove 122.

  The valve seat 114 receives the piston 116 biased in the X-axis direction in the drawing by the coil spring 112. The valve seat 114 is disposed at the bottom of the valve storage chamber 85 (see FIG. 8). The valve seat 114 is formed in an annular shape corresponding to the inner diameter of the valve storage chamber 85. A circular hole 115 is formed at the center of the valve seat 114. The rod 117 of the piston valve 113 is inserted into the hole 115. The valve seat 114 is made of an elastic member such as rubber. Therefore, when the piston 116 is elastically biased by the coil spring 112, the valve seat 114 and the piston 116 are in close contact with each other without any gap.

  As shown in FIG. 12A, in a state where no external force is applied to the rod 117, the piston valve 113 is biased by the coil spring 112, so that the piston 116 abuts against the valve seat 114. At rest. Thereby, the piston 116 and the valve seat 114 are brought into close contact with each other, and further, the valve seat 114 and the inner surface of the valve accommodating chamber 85 are brought into close contact with each other. As a result, the flow path from the ink chamber 73 of the main tank 70 to the valve storage chamber 85 through the hole 115 and the hole 100 is blocked.

  As shown in FIG. 12B, when an external force is applied to the rod 117 in the direction of the arrow 123, the piston valve 113 moves backward in the direction of the arrow 123 against the biasing force of the coil spring 112, and the piston 116. Is separated from the valve seat 114. At this time, the piston valve 113 moves back to the position P2 where the piston 116 contacts the back wall 119 of the cap 111. Thereby, the hole 101 is opened. As a result, the flow path (see the arrow 124 in FIG. 12) from the ink chamber 73 to the atmosphere through the hole 100, the hole 115, the valve storage chamber 85, and the hole 101 is opened. In other words, the ink chamber 73 communicates with the atmosphere through the hole 100, the hole 115, the valve storage chamber 85, and the hole 101. The external force applied to the rod 117 is input by the piston 181 when the plunger 172 is pushed to the back of the cylinder 171 in the pump 170 described later.

  Next, a detailed configuration of the pump 170 will be described with reference to FIG. FIG. 13 is a partially enlarged view showing a cross-sectional structure of the pump 170.

  The pump 170 supplies air to the ink chamber 73 or sucks ink from the ink chamber 73. The pump 170 alternately increases and decreases the volume of the air layer 83 by alternately supplying air to the air layer 83 (see FIG. 10) of the ink chamber 73 and sucking air from the air layer 83 of the ink chamber 73. That is, when air is supplied to the air layer 83, the air pressure in the air layer 83 increases and ink flows out in the low pressure direction. As a result, the volume of the air layer 83 increases. On the other hand, when air is sucked from the air layer 83, the air pressure in the air layer 83 decreases, and the ink flows out in the low pressure direction. As a result, the volume of the air layer 83 is reduced.

  The pump 170 is provided on the upper surface 78 of the main tank 70 as shown in FIG. The pump 170 is roughly configured to include a cylinder 171 and a plunger 172. In short, the pump 170 is a piston pump (or plunger pump) having a cylinder 171 and a plunger 172. The cylinder 171 and the plunger 172 are obtained by injection molding a synthetic resin.

  The cylinder 171 is fixed to the upper surface 78 of the main tank 70. The cylinder 171 is disposed on the upper surface 78 so that the central axis thereof is along the depth direction of the main tank 70 (X-axis direction in the drawing). The cylinder 171 defines an internal space 171A by its outer wall. The plunger 172 is inserted into the internal space 171A. With reference to the direction (insertion direction) in which the plunger 172 is inserted into the cylinder 171, the cylinder 171 has a wall surface 179 at the end on the far side in the insertion direction. A hole 173 is formed in the wall surface 179. Air in the cylinder 171 flows into and out of the ink chamber 73 through the hole 173. An opening 174 is provided at the front end of the cylinder 171 with respect to the insertion direction. The opening 174 has the same size as the inner diameter of the cylinder 171. The plunger 172 is inserted into the cylinder 171 from the opening 174. The hole 173 and the opening 174 are coaxially arranged at both ends of the cylinder 171. Hereinafter, of the both ends of the cylinder 171, the end on the side where the hole 173 is provided is referred to as a front end 175, and the end on the side where the opening 174 is provided is referred to as a rear end 176.

  An annular attachment 177 is provided at the tip 175 of the cylinder 171. A part of the fixture 177 is embedded in the tip 175, and the remaining part is exposed. Therefore, as shown in FIG. 13, the fixture 177 protrudes in the axial direction of the cylinder 171 from the tip 175 in a sectional view. A mounting groove (not shown) is formed in the mounting seat 98, and a mounting tool 177 is fitted into the mounting groove. As a result, the tip 175 of the cylinder 171 is fixed to the mounting seat 98. Further, the attachment 177 is provided with a rubbery coating. Therefore, the fixture 177 and the mounting seat 98 are in close contact with each other without any gap. Accordingly, since the path from the internal space 171A of the cylinder 171 to the ink chamber 73 is maintained in an airtight state, air mixing and air leakage do not occur in the path. As described above, the mounting seat 98 is provided on the frame 71 that forms the wall surface at the back of the valve storage chamber 85 on the front surface 80 side of the main tank 70. Therefore, the cylinder 171 is fixed to the upper surface 78 with the front end 175 facing the front surface 80.

  A seat 178 that protrudes in the radial direction of the cylinder 171 is provided at the rear end 176 of the cylinder 171. When the front end 175 of the cylinder 171 is inserted into the hole 102 of the mounting seat 99 and then the rear end 176 of the cylinder 171 reaches the mounting seat 99, the seat 178 contacts the peripheral edge of the hole 102. Thereby, the further insertion of the cylinder 171 is stopped. As described above, the mounting seat 99 is provided on the back 79 side of the main tank 70. Therefore, the cylinder 171 is fixed to the upper surface 78 with the rear end 176 facing the rear surface 79.

  The plunger 172 has a piston 181 and a rod 182. The piston 181 and the rod 182 are integrally formed. The piston 181 is provided to be slidable with respect to the inner peripheral surface of the cylinder 171. An O-ring 183 is provided between the outer peripheral surface of the piston 181 and the inner peripheral surface of the cylinder 171. Specifically, an O-ring 183 made of an annular rubber member is fitted in a groove 184 formed on the outer peripheral surface of the piston 181. Thereby, the piston 181 slides in the cylinder 171 in a state in which a gap formed between the piston 181 and the inner peripheral surface of the cylinder 171 is sealed.

  A rack gear 185 is formed on the rod 182. The rack gear 185 is formed on the upper side of the rod 182. A pinion gear 221 of a drive transmission mechanism 220 (see FIG. 17) described later meshes with the rack gear 185. Thereby, a driving force for sliding the piston 181 in the axial direction of the cylinder 171 (X-axis direction in the drawing) is transmitted to the piston 181 via the rod 182. When the piston 181 slides in the left direction in FIG. 13 in response to the driving force, the volume of the internal space 171A of the cylinder 171 decreases, and the reduced air flows into the ink chamber 73 through the holes 173 and 103. leak. Further, when the piston 181 slides in the right direction in FIG. 13 in response to the driving force, the volume of the internal space 171A of the cylinder 171 increases, and the air in the ink chamber 73 corresponding to the increased amount becomes a hole. 103 and the hole 173 and flows into the cylinder 171.

  The pump 170 is a volume obtained by adding the volume of the sub tank 21 (see FIGS. 1 and 2) to the volume of the ink tube 32 (see FIGS. 1 and 2) that is led out from the ink supply valve 130 and connected to the sub tank 21. (Hereinafter referred to as “total volume”). Generally, the capacity of the pump 170 configured as described above is determined by the cross-sectional area of the cylinder 171 and the stroke of the piston 181 (so-called pump capacity). Therefore, the cylinder 171 requires a cross-sectional area and a total length that satisfy at least the total volume. In the present embodiment, a pump 170 having a capacity equivalent to the combined volume is employed.

  In the present embodiment, the piston 181 slides with a constant stroke by a drive transmission mechanism 220 (see FIG. 17) described later. Therefore, the pump 170 always supplies a certain amount of air to the ink chamber 73 or sucks a certain amount of air.

  Next, the detailed configuration of the ink supply valve 130 will be described with reference to FIGS. 14 and 15. FIG. 14 is an exploded perspective view showing components of the ink supply valve 130. FIG. 15 is a partially enlarged view showing a cross-sectional structure of the ink supply valve 130.

  The ink supply valve 130 is a valve for allowing the ink stored in the ink chamber 73 of the main tank 70 to flow in and out. The ink supply valve 130 is accommodated in the valve accommodating chamber 88 and serves as a connection port for connecting the ink tube 32 (see FIGS. 1 and 2) to the main tank 70. As shown in FIGS. 14 and 15, the ink supply valve 130 includes a cap 131, a joint 132, a piston valve 133, and a spring unit 134. The ink supply valve 130 is configured by connecting these elements (cap 131, joint 132, piston valve 133, spring unit 134) in that order. Among the above elements, the piston valve 133 and the spring unit 134 are accommodated in the valve accommodating chamber 88. Further, the joint 132 is fitted into the opening 87 so as to plug the opening 87 (see FIG. 8). The cap 131 is attached to the periphery of the opening 87 via the joint 132.

  The joint 132 is for inserting the ink extraction pipe 149 (see FIG. 15) into the valve storage chamber 88 from the outside of the main tank 70. The ink extraction tube 149 is a needle-like tube provided at the tip of the ink tube 32 (see FIG. 1). The joint 132 is made of a synthetic resin. The joint 132 is formed in an annular shape in accordance with the inner diameter of the valve accommodating chamber 88 and the shape of the opening 87 (see FIG. 8). Specifically, the joint 132 includes a first cylindrical portion 135 that is fitted into the inner peripheral surface of the valve accommodating chamber 88 and a second cylindrical portion 136 that is in contact with the peripheral edge of the opening 87. The joint 132 is formed with a hole 137 that passes through the centers of the first cylindrical portion 135 and the second cylindrical portion 136. An ink extraction tube 149 is inserted into the hole 137. The hole 137 is formed to be slightly smaller than the outer diameter of the ink extraction tube 149. Therefore, when the ink extraction tube 149 is inserted through the hole 137, the outer peripheral surface of the ink extraction tube 149 presses against the inner surface of the hole 132 and comes into close contact therewith. Accordingly, the ink extraction tube 149 is inserted into the valve storage chamber 88 while maintaining a sealed state between the valve storage chamber 88 and the outside.

  The cap 131 covers the opening 87 (see FIG. 8) and guides the ink extraction tube 149 (see FIG. 15) to the valve storage chamber 88. The cap 131 includes a disk-shaped back wall 129 that forms the back surface, a hole 138 formed in the back wall 129, and a cylindrical side wall 139 that forms the side surface of the cap 131. A plurality of long holes 140 (two in this embodiment) are formed in the side wall 139. A projection piece (not shown) is provided on the periphery of the opening 87, and the projection piece is inserted into the long hole 140. Thereby, the cap 131 is fixed to the periphery of the opening 87.

  The spring unit 134 elastically biases the piston valve 133 housed in the valve housing chamber 88 in the depth direction of the valve housing chamber 88 (X-axis direction in FIG. 8). The spring unit 134 includes a first spring 144 and a second spring 145 made of elastic resin, and a slider 146 that can slide in the depth direction of the valve housing chamber 88. The first spring 144 and the second spring 145 are formed in a bowl shape or a hollow cone shape, and the side surfaces thereof bend when a load is applied. As shown in FIG. 14, holes 144A and 145A are formed in the first spring 144 and the second spring 145, and a path (through the thick arrow in FIG. 15) that passes through the holes 144A and 145A through the bowl-shaped interior. 164), the ink is distributed. The slider 146 is provided with a storage chamber (not shown) that stores the first spring 144 and the second spring 145, and the first spring 144 and the second spring 145 are stored in the storage chamber.

  The spring unit 134 is accommodated in the valve accommodating chamber 88 in a contracted state in advance. Therefore, in the valve accommodating chamber 88, the spring unit 134 always generates an urging force in the extending direction. The slider 146 is provided with a rib 147 for connecting the piston valve 133 and the spring unit 134. The claw 143 of the piston valve 133 is hooked on the rib 147. Although the spring unit 134 is used in the present embodiment, any material, shape, or configuration of the member that elastically biases the valve housing chamber 88 in the depth direction may be replaced with the spring unit 134. be able to. Of course, instead of the spring unit 134, a coil spring 112 (see FIG. 11) applied to the atmospheric communication valve 110 may be used.

  The piston valve 133 includes a disc-shaped back wall 141 and a cylindrical side wall 142 erected from the periphery of the back wall 141. The back wall 141 is provided with a plurality of openings 141 </ b> A (four in this embodiment) in the circumferential direction. The back wall 141 also serves as a seat that receives the urging force of the spring unit 134. A plurality of claws 143 (two in this embodiment) are provided on the side wall 142. The pawl 143 is hooked on the rib 147 of the spring unit 134 so that the piston valve 133 and the spring unit 134 are connected. The piston valve 133 is provided so as to be slidable in the depth direction of the valve accommodating chamber 88 (X-axis direction in FIG. 8). The piston valve 133 slides while forming a gap 148 having a predetermined size between the side wall 142 and the inner surface of the valve accommodating chamber 85. The gap 148 is set to a size that allows ink to flow.

  In the ink supply valve 130 configured as described above, when the ink extraction tube 149 is inserted into the valve storage chamber 88 through the hole 138 and the hole 137 as shown in FIG. The back wall 141 of the piston valve 133 is pressed against the urging force of the spring unit 134. At this time, the piston valve 133 is pushed down. As a result, the back wall 141 is separated from the joint 132. An outflow inlet 149 </ b> A through which ink flows in and out is provided on the side surface of the distal end portion of the ink extraction tube 149. Therefore, when the rear wall 141 is separated from the joint 132, the valve storage chamber 88 and the ink extraction pipe 149 communicate with each other through the outflow inlet 149A.

  In the ink supply valve 130, ink flows along the following path. When supplying ink from the ink chamber 73 to the sub tank 21, when ink flows from the ink chamber 73 through the check valve 95 into the valve storage chamber 88, the ink passes through the gap 148 between the inside of the spring unit 134 and the outer periphery thereof. Then, it flows out from the opening 141A (see the thick arrow 164 in FIG. 15). On the other hand, when the ink is sucked from the sub tank 21 into the ink chamber 73, the ink sucked into the valve storage chamber 88 through the outflow inlet 149 </ b> A flows into the buffer chamber 90, passes through the check valve 93, and flows from the flow path 92 to the air layer 83. (See the thick arrow 165 in FIG. 15).

  Next, the configuration of the cartridge mounting portion 200 will be described in detail with reference to FIGS. 16 and 17 are perspective views showing the external configuration of the cartridge mounting unit 200. FIG. 16 shows a state where the ink cartridge 50 is removed from the cartridge mounting unit 200. FIG. A state in which the ink cartridge 50 is attached to the portion 200 is shown. FIG. 18 is a side view of the cartridge mounting portion 200 as viewed from the arrow XVIII in FIG. 19 is a cross-sectional view taken along section line XIX-XIX in FIG.

  The cartridge mounting unit 200 has five colors of ink, that is, each color of cyan (C), magenta (M), yellow (Y), photo black (PBk) that is dye ink, and black (Bk) that is pigment ink. The five ink cartridges 50 corresponding to are held. The cartridge mounting unit 200 is accommodated in the ink jet recording apparatus 10.

  The cartridge mounting unit 200 includes a cartridge case 201 as shown in FIG. An opening 202 is provided on the front surface of the cartridge case 201. The ink cartridge 50 is inserted from the opening 202. When the ink cartridge 50 inserted into the cartridge case 201 is pressed in the insertion direction (X-axis direction in the figure), the ink extraction tube 149 (see FIG. 15) disposed at the back of the cartridge case 201 is ink. Inserted into the supply valve 130. Thereby, the mounting of the ink cartridge 50 to the cartridge case 201 is completed. The cartridge case 201 is configured such that the ink cartridge 50 can be inserted and removed.

  As shown in FIG. 19, an optical sensor 203 is provided at the back of the cartridge case 201. The optical sensor 203 includes a light emitting element and a light receiving element, and outputs a predetermined sensor signal (for example, an electric signal corresponding to the luminance) based on the luminance of light emitted from the light emitting element to the light receiving element. is there. A typical example of the optical sensor 203 is a transmissive photo interrupter. The optical sensor 203 is provided corresponding to the ink cartridge 50. Therefore, in this embodiment, five optical sensors 203 are provided. The optical sensor 203 is arranged so that the detection unit 75 enters a detection region formed between the light emitting element and the light receiving element of the optical sensor 203. In a state where the shielding part 157 of the sensor arm 150 enters the detection part 75, the detection area is shielded by the shielding part 157. At this time, the ink jet recording apparatus 10 determines that “there is remaining ink”. On the other hand, in a state where the shielding unit 157 has left the detection unit 75, the detection area is not shielded. At this time, the inkjet recording apparatus 10 determines that “there is no ink remaining”.

  A drive transmission mechanism 220 is provided on the back side of the cartridge mounting unit 200. The drive transmission mechanism 220 includes five pinion gears 221, a shaft 222, a link rod 223, a shaft 224, a first transmission gear 225, and a second transmission gear 226.

  The pinion gear 221 is meshed with the rack gear 185 in a state where the ink cartridge 50 is mounted in the cartridge case 201. In the present embodiment, five pinion gears 221 are disposed corresponding to the five plungers 172 of the ink cartridge 50. As shown in FIGS. 16 and 17, the pinion gear 221 is formed in a substantially semicircular shape. A gear is formed on the arc portion 228 of the pinion gear 221.

  The five pinion gears 221 are fixed to a uniaxial shaft 222. Therefore, when the shaft 222 rotates, all the pinion gears 221 rotate at the same rotational speed in the same direction as the rotation direction. A link rod 223 is connected to one end of the shaft 222. A predetermined driving force is transmitted to the shaft 222 by the link rod 223. The link rod 223 is also connected to the shaft 224. In short, one end of the link rod 223 is connected to the shaft 222 and the other end is connected to the shaft 224. A first transmission gear 225 is fixed to the shaft 224. The second transmission gear 226 is meshed with the first transmission gear 225.

  The second transmission gear 226 is connected to a drive source such as a motor. The driving source is also connected to a driving system such as a paper feeding device 12 and a conveying device 13 that constitute the ink jet recording apparatus 10. The drive source is controlled to perform a predetermined operation by a main control unit (not shown) that controls the inkjet recording apparatus 10 in an integrated manner.

  When a predetermined driving force is transmitted from the driving source to the second transmission gear 226, the driving force is transmitted to the rack gear 185 via the first transmission gear 225, the shaft 224, the link rod 223, the shaft 222, and the pinion gear 221. Is done. Thereby, the piston 116 slides so as to reciprocate in the cylinder 171 together with the rack gear 185.

  Hereinafter, with reference to FIG. 20, an ink supply operation by the ink supply apparatus 11 according to the present embodiment will be described. FIG. 20 is a schematic diagram for explaining the ink supply operation. In FIG. 20, the sensor arm 150 is omitted.

  Since the ink supply device 11 according to this embodiment is configured as described above, ink is supplied from the main tank 70 to the sub tank 21 in the following manner. The ink is supplied to the sub tank 21 in a state where the valve 37 (see FIG. 1) is opened and the sub tank 21 is opened to the atmosphere.

  As shown in FIG. 20A, when the drive source is operated in a direction in which the plunger 172 is pushed out from the cylinder 171 to the maximum in the direction in which the plunger 172 is pushed into the cylinder 171, the air in the cylinder 171 becomes a hole. 173 and the hole 103 (see FIG. 13), the ink is fed into the ink chamber 73 of the main tank 70. As a result, the pressure of the air layer 83 in the ink chamber 73 increases. When the pressure in the air layer 83 becomes higher than the pressure in the valve accommodating chamber 88 (see FIG. 15), the check valve 95 (see FIG. 15) opens the hole 89. By opening the hole 89, ink is supplied from the main tank 70 to the sub tank 21 through the flow path indicated by the solid line arrow 23 in FIG. More specifically, first, when the hole 89 is opened, the ink stored in the ink chamber 73 flows out to the valve storage chamber 88 through the hole 89 (see FIG. 15). At this time, the volume of the air layer 83 increases by an amount corresponding to the amount of air flowing in from the cylinder 171. The ink flowing into the valve housing chamber 88 passes through and around the spring unit 134 and flows into the ink tube 32 from the outflow inlet 149A (see FIG. 15) of the ink extraction tube 149. Then, ink is supplied to the sub tank 21 through the ink tube 32. When the plunger 172 is pushed all the way into the cylinder 171, as shown in FIG. 20C, the sub tank 21 and the ink tube 32 are filled with ink.

  In the ink supply apparatus 11 according to the present embodiment, ink is sucked from the sub tank 21 to the main tank 70 in the following manner. The ink is sucked into the main tank 70 in a state where the valve 37 is opened and the sub tank 21 is opened to the atmosphere.

  As shown in FIG. 20C, when the drive source is operated in a direction in which the plunger 172 is pulled out from the cylinder 171 from a state where the plunger 172 is pushed into the inner part of the cylinder 171, the air layer 83 of the ink chamber 73 is Air is sucked into the cylinder 171 through the hole 103 and the hole 173 (see FIG. 13). As a result, the pressure of the air layer 83 in the ink chamber 73 decreases. When the pressure in the air layer 83 becomes lower than the pressure in the valve accommodating chamber 88 (see FIG. 15), the check valve 93 (see FIG. 15) opens the flow path 92. As a result, the ink is returned from the sub tank 21 to the main tank 70 through the flow path indicated by the dashed arrow 24 in FIG. More specifically, first, the ink in the valve storage chamber 88 is carried upward through the flow path 92 by opening the flow path 92. The ink carried upward through the flow path 92 flows into the ink chamber 73 from the opening 94. On the other hand, as the ink flows into the ink chamber 73, the ink in the sub tank 21 flows into the ink supply valve 130 through the ink tube 32.

  As shown in FIG. 20A, when the plunger 172 is pulled out from the cylinder 171 to the maximum extent, the volume of the air layer 83 decreases by an amount corresponding to the amount of air returned to the cylinder 171. At this time, all the ink in the sub tank 21 and the ink tube 32 is returned to the ink chamber 73. When ink flows from the sub tank 21 into the ink chamber 73 of the main tank 70, bubbles in the ink tube 32 or the sub tank 21 flow into the ink chamber 73 together with the ink. Bubbles that flow into the ink chamber 73 pass through the flow path 92 and rise to the upper layer of the ink chamber 73 so as to bypass the sensor arm 150 (see FIG. 7), and reach the air layer 83. As a result, bubbles generated in the sub tank 21 and the ink tube 32 can be separated from the ink and removed. After all the ink is returned to the ink chamber 73, as described above, ink is supplied from the main tank 70 to the sub tank 21, so that ink that does not contain bubbles is supplied to the sub tank 21 via the ink tube 32. The As a result, all the ink in the sub tank 21 is replaced with the ink stored in the ink chamber 73, so that the viscosity of the ink in the sub tank 21 is equal to the viscosity of the ink in the main tank 70.

  In addition, the ink supply device 11 according to the present embodiment employs a pump 170 that increases or decreases the volume of the air layer 83 as the pressure changes. Therefore, even if air flows into the pump 170, ink does not flow in. Therefore, the failure of the pump 170 due to the inflow of ink is reduced. As a result, the reliability of the pump 170 is improved.

  Further, as described above, the ink cartridge 50 according to the present embodiment is formed with the flow path 91 and the flow path 92, so that the ink flowing from the sub tank 21 through the tube 21 into the main tank 70 is the ink. Without passing through the chamber 73, the air is guided upward through the flow path 92 to the air layer 83. Therefore, the ink flows through the main tank 70 so as to bypass the sensor arm 150. Thereby, bubbles contained in the ink do not adhere to the sensor arm 150. As a result, unintentional swinging of the sensor arm 150 caused by bubbles adhering to the sensor arm 150 and erroneous detection of the optical sensor 203 are prevented, thereby improving the detection accuracy of the ink storage amount.

  In addition, embodiment mentioned above is only an example of this invention, and can change suitably embodiment in the range which does not change the summary of this invention. In the above-described embodiment, the example in which the present invention is applied to the mechanism for flowing ink into and out of the sub tank 21 from the main tank 70 of the ink cartridge 50 through the ink tube 32 has been described. On the other hand, for example, when the carriage 30 is moved to a predetermined position, the sub tank 21 is connected to the main tank 70 mounted on the ink jet recording apparatus 10, whereby the ink is transferred between the main tank 70 and the sub tank 21. The present invention can also be applied to a mechanism that flows in and out.

FIG. 1 is a schematic cross-sectional view showing an internal mechanism of the ink jet recording apparatus 10. 2 is an enlarged view of a main part showing the recording unit 14 of FIG. 1 in detail, FIG. 2 (a) shows a state where the opening 42 of the valve 37 is closed, and FIG. 2 (b) shows the valve 37. The state where the opening 42 is opened is shown. 3A and 3B are perspective views showing an external configuration of the ink cartridge 50. FIG. 3A shows a state where the case 52 is assembled, and FIG. 3B shows a state where the case 52 is disassembled. . FIG. 4 is a perspective view showing an external configuration of the ink cartridge 50. FIG. 5 is a perspective view showing the internal configuration of the ink cartridge 50. FIG. 6 is a side view as seen from the direction of the arrow VI in FIG. 5 and shows the internal configuration of the ink cartridge 50. 7 is a cross-sectional view taken along section line VII-VII in FIG. FIG. 8 is an exploded cross-sectional view of the ink cartridge 50. FIG. 9 is a partial cross-sectional view taken along section line IX-IX in FIG. FIG. 10 is a cross-sectional view showing a state where a predetermined amount of ink is injected into the ink chamber 73. FIG. 11 is an exploded perspective view showing components of the atmosphere communication valve 110. FIG. 12 is a partially enlarged view showing a cross-sectional structure of the atmosphere communication valve 110. FIG. 12A shows a state where the piston 116 is stationary at the position P1, and FIG. 12B shows a state where the piston 116 is at the position P2. Shows a stationary state. FIG. 13 is a partially enlarged view showing a cross-sectional structure of the pump 170. FIG. 14 is an exploded perspective view showing components of the ink supply valve 130. FIG. 15 is a partially enlarged view showing a cross-sectional structure of the ink supply valve 130. FIG. 16 is a perspective view illustrating an external configuration of the cartridge mounting unit 200, and shows a state where the ink cartridge 50 is removed from the cartridge mounting unit 200. FIG. 17 is a perspective view illustrating an external configuration of the cartridge mounting unit 200, and shows a state where the ink cartridge 50 is mounted on the cartridge mounting unit 200. FIG. 18 is a side view of the cartridge mounting portion 200 as viewed from the arrow XVIII in FIG. 19 is a cross-sectional view taken along section line XIX-XIX in FIG. FIG. 20 is a schematic diagram for explaining an ink supply operation.

DESCRIPTION OF SYMBOLS 10 ... Inkjet recording device 11 ... Ink supply device 21 ... Sub tank 32 ... Ink tube 50 ... Ink cartridge 70 ... Main tank 75 ... Detection part 90 ... Buffer chamber 91 ... Channel 92 ... Channel 92A ... First vertical channel 92B ... Horizontal channel 92C ... Second vertical channel 93 ... Check valve 95 ... Check valve 110 ... Air communication valve 130 ... Ink supply valve 150 ... Sensor arm 157 ... Shielding part 170 ... Pump 171 ... Cylinder 172 ... Plunger 181 ... Piston 182 ... Rod 185 ... Rack gear 200 ... Cartridge mounting part

Claims (6)

An ink tank having an ink storage chamber for storing ink and forming an air layer in the upper layer portion;
A communication hole provided on the wall surface of the ink tank, allowing the ink to flow out from the ink tank to the outside and allowing the ink to flow from the outside to the ink tank;
An arm member provided so as to be swingable in the ink storage chamber, and for detecting an ink storage amount;
First, the ink that has flowed into the ink tank through the communication hole passes through the space separated from the space in the ink storage chamber in which the arm member is provided and bypasses the arm member to be guided to the upper layer portion. An ink flow path;
A second ink flow path for guiding the ink stored in the ink storage chamber to the communication hole through a space separated from the first ink flow path;
Provided in the second ink flow path, opened on condition that the ink storage chamber has a positive pressure with respect to the outside, and closed on condition that the ink storage chamber has a negative pressure on the outside. And a second check valve.   Provided in the first ink flow path, opened on condition that the ink reservoir chamber has a negative pressure with respect to the outside, and closed on condition that the ink reservoir chamber has a positive pressure with respect to the outside. The ink cartridge according to claim 1, further comprising a first check valve. The upper portion, the ink cartridge according to claim 1 or 2 the amount of ink predetermined is a region where the air layer is formed when injected into the ink storage chamber is present. The first ink channel extends from the communication hole vertically upward along the wall surface, and extends in the horizontal direction along the wall surface from the end of the first vertical channel. a horizontal flow path is from claim 1 is extended vertically upward along the wall surface is constituted by a second vertical flow path leading to the upper portion from the end of the horizontal channel 3 The ink cartridge according to any one of the above. Provided in the first ink flow path, opened on condition that the ink reservoir chamber has a negative pressure with respect to the outside, and closed on condition that the ink reservoir chamber has a positive pressure with respect to the outside. Further comprising a first check valve,
The first ink channel extends from the communication hole vertically upward along the wall surface, and extends in the horizontal direction along the wall surface from the end of the first vertical channel. And a second vertical flow path extending vertically upward along the wall surface from the end of the horizontal flow path to the upper layer part, and
The ink cartridge according to claim 1, wherein the first check valve is provided in the horizontal flow path. The ink cartridge according to claim 4 or 5 , wherein a buffer chamber for buffering ink flow is provided in the horizontal flow path.

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