JP2017154507A - Liquid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid injection device suppressing variations of displacement of sub-tanks and being capable of preventing interruption of a job due to liquid exhaustion.SOLUTION: A liquid injection device includes: an ink jet head H injecting ink supplied from an ink cartridge CTR housing the ink; an ink supply passage 20 connecting between the ink cartridge CTR and the ink jet head H; a plurality of sub-tanks 30 storing the ink in the ink supply passage 20 and having space volumes storing the ink varying by displacement of flexible members 32; and pressure addition means 40 adding individual different pressures to the flexible members 32 of the plurality of sub-tanks 30. A configuration of the liquid injection device as described above is employed.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a liquid ejecting apparatus.

  2. Description of the Related Art Conventionally, an ink jet recording apparatus is known as one of liquid ejecting apparatuses that eject liquid from a nozzle to a target. The ink jet recording apparatus includes a recording head for ejecting ink, and ejects ink from nozzles formed on the recording head while performing relative movement between the recording head and the recording medium to perform printing on the recording medium. (For example, refer to Patent Document 1).

  Japanese Patent Application Laid-Open No. 2004-133830 discloses that ink tanks can be replaced without interrupting recording by the recording head, and the ink supply paths between the ink tank and the recording head have different sizes that can store ink. An ink jet printer having two subtanks is described. The two sub tanks have different sizes, and the smaller sub tank is arranged on the upstream side.

  Since the small sub-tank is connected to the large sub-tank, when the small sub-tank on the upstream side is full, it can be seen that the large sub-tank on the downstream side is also full. If the small sub tank on the upstream side is not full, it can be determined that the ink tank is out of ink. For this reason, a displacement sensor is provided in a small sub-tank, and near-ink end detection is performed to instruct replacement of the ink tank, and printing is continued using the ink in the large sub-tank on the downstream side while replacing the ink tank. .

JP 2005-96152 A

  By the way, whether or not the sub tank is full needs to detect the displacement of the flexible member that deforms in a concave shape in accordance with the magnitude of the negative pressure provided in the sub tank. However, since the displacement of the flexible member is greatly influenced by the deformation characteristics of the material, the variation of the displacement becomes large. In the configuration of the prior art, for example, the displacement of the large subtank precedes the displacement of the small subtank. May be detected.

  SUMMARY An advantage of some aspects of the invention is that it provides a liquid ejecting apparatus capable of suppressing variation in displacement of subtanks and preventing interruption of a job due to running out of liquid.

In order to solve the above-described problems, the present invention provides a liquid ejecting head that ejects liquid supplied from a liquid container that contains a liquid, and a liquid supply that connects the liquid container and the liquid ejecting head. A plurality of sub-tanks in which liquid is stored in the channel and the liquid supply channel, and a space volume in which the liquid is stored is changed by displacement of the flexible member, and different pressures for the flexible members in the plurality of sub-tanks A liquid ejecting apparatus having pressure applying means for applying the pressure is adopted.
By adopting such a configuration, in the present invention, pressure applying means is provided, and different pressures are respectively applied to the flexible members of the plurality of sub tanks. Thus, by positively applying pressure from the outside to the flexible members of the plurality of sub tanks, the influence of the deformation characteristics of the flexible members can be reduced, and the plurality of sub tanks can be deformed with a time difference. it can. For this reason, variation in displacement of the plurality of sub tanks can be suppressed, a change with time in the pressure state in the liquid supply path can be observed reliably, and the replacement timing of the liquid container can be grasped.

Further, in the present invention, the pressure applying means has a plurality of urging members that respectively urge the flexible members of the plurality of sub-tanks, and the plurality of urging members include a spring constant, and A configuration is employed in which at least one of a stroke until the flexible member is displaced to the bottom dead center and a pressurizing area for pressurizing the flexible member are different.
By adopting such a configuration, in the present invention, different pressures are applied to the flexible members of the plurality of subtanks by the plurality of urging members. The biasing member has a plurality of sub-tanks by varying at least one of a spring constant, a stroke until the flexible member is displaced to the bottom dead center, and a pressurizing area for pressurizing the flexible member. The pressure applied to the flexible member can be easily adjusted.

Moreover, in this invention, the said pressure addition means employ | adopts the structure that the said biasing member has a plate-shaped pressure receiving member which adjusts the pressurization area which pressurizes the said flexible member.
By adopting such a configuration, in the present invention, a plate-like pressure receiving member is provided, and the pressing area where the biasing member presses the flexible member is adjusted. By providing the plate-shaped pressure receiving member, the pressing area of the biasing member with respect to the flexible member can be kept constant. Therefore, the influence of the deformation characteristics of the flexible member is reduced, and a plurality of sub tanks are separated by time differences. It can be reliably deformed.

In the present invention, the pressure applying means maximizes the pressure applied to the flexible member of the sub-tank located on the most upstream side among the plurality of sub-tanks, and is located downstream of the sub-tank. A configuration is adopted in which the pressure applied to the flexible member of the sub-tank located at is reduced toward the downstream side.
By adopting such a configuration, in the present invention, the plurality of sub tanks can be deformed in order from the upstream side with a time difference, so that the temporal change in the pressure state in the liquid supply path can be more reliably observed. The replacement timing of the liquid container can be grasped. Further, according to this configuration, the sub-tank located on the most downstream side among the plurality of sub-tanks is displaced last, so that the pressure loss when the liquid is ejected from the liquid ejecting head is reduced as the ink end is approached. Can do.

Moreover, in this invention, the structure that the displacement sensor which detects the displacement of the said flexible member is provided in at least one among these subtanks is employ | adopted.
By adopting such a configuration, in the present invention, a displacement sensor is provided in at least one of the plurality of sub-tanks, and the displacement of the flexible member is detected, thereby making it easy to grasp the replacement timing of the liquid container. become. Further, since the order of deformation of the plurality of sub-tanks can be grasped by pressure adjustment by the pressure applying means, if the displacement sensor is provided in at least one of the plurality of sub-tanks, the temporal change in the pressure state in the liquid supply path can be detected. Can be observed.

Further, in the present invention, a configuration is adopted in which the displacement sensor is provided at least in a sub tank located at the most upstream side among the plurality of sub tanks.
By adopting such a configuration, in the present invention, the displacement sensor is provided in the most upstream sub-tank among the plurality of sub-tanks, and is the flexible member that is closest to the liquid container and has the highest responsiveness to the remaining amount of liquid. The displacement of is detected. As a result, the remaining amount of liquid in the liquid container can be accurately detected, and after the detection, the job currently being performed can be continued with the liquid stored in the downstream sub-tank with a small pressure loss. .

Further, in the present invention, each of the plurality of sub-tanks has an introduction port for introducing a liquid at a lower portion, and an outlet port for deriving a liquid is provided at an upper portion. A configuration is adopted in which the openings are opened in the same direction in the horizontal direction.
By adopting such a configuration, in the present invention, the sub-tank inlet is provided in the lower part, the sub-tank outlet is provided in the upper part, and each is opened in the same horizontal direction, so that the inlet is introduced into the sub-tank from the inlet. The liquid that has been discharged flows along the inner wall from the lower part of the sub tank and is discharged from the outlet through the upper part. For this reason, while the sediment component of the liquid settled in the lower part of the sub tank can be stirred, the discharge property of the bubbles accumulated in the upper part of the sub tank can be improved.

In the present invention, a configuration is adopted in which the plurality of sub-tanks are arranged from the lower part to the upper part in the gravity direction in order from the upstream one.
By adopting such a configuration, in the present invention, a plurality of sub-tanks are arranged in the direction of gravity, and arranged such that the upstream side is the lower part and the downstream side is the upper part. Accordingly, the bubbles can easily pass through the sub tank on the downstream side by buoyancy and are easily discharged from the liquid ejecting head, so that the bubble discharge performance can be improved.

Further, in the present invention, the liquid supply path upstream of the plurality of sub tanks is provided with a one-way valve that allows only the flow of liquid toward the downstream side, and is disposed downstream of the plurality of sub tanks. The liquid supply path is provided with a self-sealing valve that opens the liquid supply path when the downstream side reaches a predetermined negative pressure.
By adopting such a configuration, in the present invention, a one-way valve is provided on the upstream side of the plurality of sub tanks to prevent the backflow of the liquid to the liquid container, and further on the downstream side of the plurality of sub tanks. A self-sealing valve can be provided to reliably prevent liquid leakage from the liquid ejecting head.

Moreover, in this invention, the structure of having a pressurizing means which pressurizes the said liquid container is employ | adopted.
By adopting such a configuration, in the present invention, it is possible to increase the supply pressure of the liquid supplied to the liquid ejecting head via the liquid supply path by providing a pressurizing unit and pressurizing the liquid container. This enables high-speed printing from the liquid ejecting head.

In the present invention, a configuration is adopted in which the smallest pressure among the pressures applied by the pressure applying unit is larger than the supply pressure required for the liquid ejecting head to eject liquid.
By adopting such a configuration, in the present invention, the liquid in the sub tank can be ejected from the liquid ejecting head by the pressure applied to the sub tank even when the remaining amount of the liquid in the liquid container is reduced. It is possible to supply a stable liquid until it disappears.

1 is a plan view showing a printer in an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating an ink supply system of a printer according to an embodiment of the invention. It is a front side perspective view of the sub tank in the embodiment of the present invention. It is a back side perspective view of a sub tank in an embodiment of the present invention. It is arrow AA sectional drawing in FIG. It is a perspective view which shows the inside of the sub tank in embodiment of this invention. It is an expansion perspective view which shows the inside of the sub tank in embodiment of this invention. FIG. 6 is a diagram showing the relationship between the remaining amount of ink in the printer and the pressure in the ink supply path over time in the embodiment of the present invention. FIG. 6 is a diagram showing the relationship between the remaining amount of ink in the printer and the pressure in the ink supply path over time in the embodiment of the present invention.

  Hereinafter, embodiments of a liquid ejecting apparatus according to the invention will be described with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size. In this embodiment, an ink jet printer (hereinafter referred to as a printer) is exemplified as the liquid ejecting apparatus according to the invention.

FIG. 1 is a plan view showing a printer PRT according to an embodiment of the present invention.
The printer PRT shown in FIG. 1 is a device that performs a printing process while conveying a sheet-like recording medium M such as paper or a plastic sheet. The printer PRT includes a housing PB, an inkjet mechanism IJ that ejects ink onto the recording medium M, an ink supply mechanism IS that supplies ink to the inkjet mechanism IJ, a transport mechanism CV that transports the recording medium M, and an inkjet mechanism. A maintenance mechanism MN that performs IJ maintenance operations and a control device CONT that controls these mechanisms are provided.

  Hereinafter, an XYZ rectangular coordinate system is set, and the positional relationship of each component will be described with reference to the XYZ rectangular coordinate system as appropriate. In this embodiment, the conveyance direction of the recording medium M is the X-axis direction, the direction orthogonal to the X-axis direction on the conveyance surface of the recording medium M is the Y-axis direction, and the direction perpendicular to the plane including the X-axis and the Y-axis Is expressed as the Z-axis direction.

  The housing PB is formed so that the Y-axis direction is the longitudinal direction. Each part of the inkjet mechanism IJ, the ink supply mechanism IS, the transport mechanism CV, the maintenance mechanism MN, and the control device CONT is attached to the housing PB. A platen 13 is provided in the housing PB. The platen 13 is a support member that supports the recording medium M. The platen 13 is disposed in the central portion of the housing PB in the X-axis direction. The platen 13 has a flat surface 13a directed to the + Z side. The flat surface 13a is used as a support surface that supports the recording medium M.

  The transport mechanism CV includes a transport roller, a motor that drives the transport roller, and the like (both not shown). The transport mechanism CV transports the recording medium M from the −X side of the housing PB into the housing PB and discharges the recording medium M from the + X side of the housing PB to the outside of the housing PB. The transport mechanism CV transports the recording medium M so that the recording medium M passes over the platen 13 inside the housing PB. In the transport mechanism CV, the transport timing, transport amount, and the like are controlled by the control device CONT.

  The inkjet mechanism IJ includes an inkjet head H (liquid ejection head) that ejects ink (liquid) and a head moving mechanism AC that holds and moves the inkjet head H. The ink jet head H ejects ink toward the recording medium M sent out on the platen 13. The inkjet head H has an ejection surface Ha on which nozzles that eject ink are formed. The ejection surface Ha is directed in the Z-axis direction and is disposed so as to face the support surface of the platen 13.

  The head moving mechanism AC has a carriage CA. The inkjet head H is fixed to the carriage CA. The carriage CA is configured to be movable along a guide shaft 8 installed in the longitudinal direction (Y-axis direction) of the housing PB. The inkjet head H and the carriage CA are disposed on the + Z side with respect to the platen 13.

  The head moving mechanism AC includes a carriage CA, a pulse motor 9, a drive pulley 10 that is rotationally driven by the pulse motor 9, and a side (+ Y side) on which the drive pulley 10 is provided in the longitudinal direction of the housing PB. A driven pulley 11 provided on the opposite side (−Y side) and a timing belt 12 spanned between the driving pulley 10 and the driven pulley 11 are provided.

  The carriage CA is connected to the timing belt 12. The carriage CA is provided to be movable in the Y-axis direction as the timing belt 12 rotates. When moving in the Y-axis direction, the carriage CA is guided by the guide shaft 8.

  The maintenance mechanism MN is disposed at the home position of the inkjet head H. This home position is set in an area outside the area where printing is performed on the recording medium M. In the present embodiment, the home position is set on the + Y side of the platen 13. The home position is a place where the inkjet head H stands by when the printer PRT is turned off or when recording is not performed for a long time.

  The maintenance mechanism MN includes a cap member CP that covers the nozzles of the inkjet head H, a wiping member WP that wipes the ejection surface Ha, and the like. A suction device SC such as a suction pump is connected to the cap member CP. The cap member CP can suck ink from the inkjet head H by the suction device SC.

  The ink supply mechanism IS supplies ink to the inkjet head H. The ink supply mechanism IS has a plurality of ink cartridges CTR (liquid container). The printer PRT of the present embodiment employs a configuration (off-carriage type) in which the ink cartridge CTR is not mounted on the carriage CA, unlike the inkjet head H.

FIG. 2 is a schematic diagram illustrating an ink supply system of the printer PRT according to the embodiment of the present invention.
The ink supply mechanism IS has an ink supply path 20 (liquid supply path) that connects between the ink cartridge CTR and the inkjet head H. In the ink supply path 20, a check valve 21 (one-way valve), a plurality of sub tanks 30, and a self-sealing valve 22 are provided. The ink supply path 20 is provided in each of the plurality of ink cartridges CTR (see FIG. 1).

  The check valve 21 is provided in the ink supply path 20 upstream of the plurality of sub tanks 30. In other words, the check valve 21 is provided in the ink supply path 20 upstream of the first sub tank 30A located on the most upstream side of the plurality of sub tanks 30 and downstream of the ink cartridge CTR. The check valve 21 is a valve that allows only the flow of ink from the ink cartridge CTR toward the inkjet head H toward the downstream side. The check valve 21 can prevent the ink from flowing back to the ink cartridge CTR.

  The self-sealing valve 22 is provided in the ink supply path 20 on the downstream side of the plurality of sub tanks 30. That is, the self-sealing valve 22 is provided in the ink supply path 20 on the downstream side of the second sub tank 30B located on the most downstream side among the plurality of sub tanks 30 and on the upstream side of the inkjet head H. Yes. The self-sealing valve 22 is a valve that opens the ink supply path 20 when the downstream side where the inkjet head H is provided reaches a predetermined negative pressure. This self-sealing valve 22 prevents excessive supply of ink, and can reliably prevent ink leakage from the inkjet head H.

  Since the configuration of the self-sealing valve 22 is known, a detailed description thereof is omitted, but a valve body (not shown) that opens and closes the ink supply path 20 and a biasing member that biases the valve body in a closing direction (not shown). And a flexible member (not shown) that pushes the valve body against the urging of the urging member when the ink supply path 20 becomes a negative pressure due to atmospheric pressure. That is, the self-sealing valve 22 opens the ink supply path 20 by the difference between the pressure of the ink supply path 20 and the atmospheric pressure. By ensuring that the ink supply pressure to the self-sealing valve 22 is equal to or higher than a predetermined pressure, the inkjet head H can eject ink normally.

  The ink cartridge CTR is connected to a pressurizing pump 23 (pressurizing means). The pressurizing pump 23 pressurizes the pressurizing chamber 25 that houses the ink pack 24 of the ink cartridge CTR. When the pressure pump 23 is driven, air is sent into the pressure chamber 25 to pressurize the ink pack 24. When the ink pack 24 is pressurized, the ink supply pressure of the ink supply path 20 is increased, and for example, high-speed printing from the inkjet head H becomes possible. The pressure in the ink supply path 20 is large on the ink cartridge CTR side (upstream side) and small on the inkjet head H side (downstream side) due to pressure loss in the flow path.

  The sub tank 30 stores ink in the ink supply path 20, and the space volume in which the ink is stored changes due to the displacement of the flexible member 32. A plurality of the sub tanks 30 are provided in the ink supply path 20, and in this embodiment, two of the first sub tank 30A and the second sub tank 30B are provided in series. The sub tank 30 has a configuration in which a flexible member 32 is bonded to a housing 31, and the space volume of the ink chamber 33 formed inside varies depending on the remaining amount of ink. The flexible member 32 is formed from, for example, a single-layer or multi-layer flexible resin film (for example, a PET / CPP laminated film).

Next, the configuration and arrangement of the sub tank 30 will be described in detail with reference to FIGS.
FIG. 3 is a front perspective view of the sub tank 30 in the embodiment of the present invention. FIG. 4 is a rear perspective view of the sub tank 30 in the embodiment of the present invention. FIG. 5 is a cross-sectional view taken along line AA in FIG. FIG. 6 is a perspective view showing the inside of the sub tank 30 in the embodiment of the present invention. FIG. 7 is an enlarged perspective view showing the inside of the sub tank 30 in the embodiment of the present invention.

  As shown in FIG. 3, the plurality of sub tanks 30 of the present embodiment are unitized and provided integrally. In this embodiment, two sets of the first sub tank 30A and the second sub tank 30B are provided in one housing 31. That is, not only the first sub tank 30A and the second sub tank 30B provided in the ink supply path 20 but also the first sub tank 30A and the second sub tank 30A provided in another ink supply path 20 are provided in the casing 31. Two sub tanks 30B are also provided. Thus, unitizing the plurality of sub tanks 30 can contribute to the reduction of the number of parts and cost.

  The casing 31 is formed by combining the first plate 31a and the second plate 31b. As shown in FIG. 5, the first plate 31a has an ink chamber 33 and an inlet port 36 and an outlet port 37 for introducing ink into the ink chamber 33. On the other hand, the second plate 31b is provided with a pressure applying means 40 and a displacement sensor 50 described later. As shown in FIG. 6, when the second plate 31b and the flexible member 32 are removed, the ink chamber 33 is exposed. The ink chamber 33 has a circular inner wall 34. The inner wall 34 has a square shape (conical shape) that opens to the second plate 31b side in a cross-sectional view shown in FIG.

  A groove portion 35 is provided in the ink chamber 33. As shown in FIG. 6, the groove portion 35 is formed in the vertical direction of the central portion of the ink chamber 33. The groove 35 is an area formed deeper than the first plate 31a, and an ink inlet 36 and an outlet 37 are formed in this area. Even if the flexible member 32 is recessed to the bottom dead center by the groove portion 35, the flow path between the ink inlet 36 and the outlet 37 is secured, so that the ink supply path 20 is not blocked. .

  As shown in FIG. 7, the introduction port 36 is provided in the lower part of the sub tank 30. The introduction port 36 opens in a tangential direction with respect to the circular inner wall 34. On the other hand, the outlet 37 is provided in the upper part of the sub tank 30. The outlet 37 is opened in a tangential direction with respect to the circular inner wall 34. Moreover, the inlet 36 and the outlet 37 are opened in the same direction in the horizontal direction. According to this arrangement, ink that has flowed in the tangential direction of the inner wall 34 from the lower part of the sub tank 30 circulates along the inner wall 34 and is discharged from the upper part of the sub tank 30 through the outlet 37. For this reason, the sediment component of the ink settled in the lower part of the sub tank 30 can be stirred, and the discharge property of the bubbles accumulated in the upper part of the sub tank 30 can be improved.

  Moreover, as shown in FIG. 4, the some sub tank 30 is arrange | positioned from the lower part of the gravity direction to the upper part in an order from the upstream thing. In the present embodiment, in the ink supply path 20, the upstream first sub-tank 30 </ b> A is disposed at the lower part, and the downstream second sub-tank 30 </ b> B is disposed at the upper part. The lead-out port 37 of the first sub tank 30A and the introduction port 36 of the second sub tank 30B are connected by a substantially U-shaped ink supply path 20. That is, the ink supply path 20 is connected to the outlet 37 of the first sub tank 30A and the inlet 36 of the second sub tank 30B in the same direction in the horizontal direction. Thereby, bubbles accumulated in the upstream first sub-tank 30A can easily pass through the downstream second sub-tank 30B by buoyancy, and are easily discharged from the inkjet head H, thereby improving the bubble discharge performance. Can do.

  Returning to FIG. 2, the printer PRT includes pressure applying means 40 that applies different pressures to the flexible members 32 of the plurality of sub-tanks 30. The pressure applying means 40 includes a plurality of urging members 41 that respectively urge the flexible members 32 of the plurality of sub tanks 30. The biasing member 41 varies at least one of a spring constant, a stroke until the flexible member 32 is displaced to the bottom dead center, and a pressing area for pressing the flexible member 32. The pressure applied to the flexible members 32 of the plurality of sub tanks 30 can be easily adjusted.

  The pressure applying means 40 of the present embodiment includes a plate-shaped pressure receiving member 42 that adjusts the pressing area where the biasing member 41 presses the flexible member 32. The pressure receiving member 42 maintains a constant pressure area for the relatively soft flexible member 32. In this embodiment, the pressure receiving member 42 that pressurizes the flexible member 32 of the first sub-tank 30A and the pressure receiving member 42 that pressurizes the flexible member 32 of the second sub-tank 30B have the same shape. The area is set to be the same. As shown in FIG. 5, the pressure receiving member 42 includes a plate portion 43 that contacts the flexible member 32, and a shaft portion 44 that is connected to the plate portion 43.

  The plate part 43 has a substantially disk shape, and the front side that contacts the flexible member 32 is formed in a flat surface. On the back side of the plate portion 43, minute irregularities serving as a seat for the urging member 41 are formed, and a shaft portion 44 is provided at the center thereof. The shaft portion 44 is engaged with a through hole 45 penetrating the second plate 31b so as to be slidable in the longitudinal direction. The urging member 41 is disposed between the second plate 31b and the plate portion 43 of the pressure receiving member 42, and urges the flexible member 32 in a direction to reduce the space volume of the ink chamber 33. Yes.

  As shown in FIGS. 2 and 5, since the first sub tank 30A and the second sub tank 30B of the present embodiment have the same shape, the flexible member 32 of the biasing member 41 is displaced to the bottom dead center. The strokes of are the same. For this reason, the pressure applying means 40 of this embodiment includes a biasing member 41A that pressurizes the flexible member 32 of the first sub tank 30A and a biasing member that pressurizes the flexible member 32 of the second sub tank 30B. The spring constant of 41B is changed, and different pressures are applied with the same stroke and the same pressure area. The spring constant of the urging member 41 can be changed by changing the spring material, the number of turns, and the like.

  In the present embodiment, the biasing member 41A is, for example, 10.7 to 9.2 N (Newton) with a stroke up to the bottom dead center of the flexible member 32 with respect to the sub tank 30 capable of containing, for example, 39 g (grams) of ink. The spring constant is adjusted so that the biasing member 41B exhibits a spring force of 8.3 to 7.4 N (Newton), for example. In other words, the pressure applying means 40 maximizes the pressure applied to the flexible member 32 of the first sub tank 30A located on the most upstream side, and the second pressure located on the downstream side of the first sub tank 30A. The pressure applied to the flexible member 32 of the sub tank 30B is reduced, and the pressure applied to the plurality of sub tanks 30 is reduced toward the downstream side.

  As shown in FIG. 2, at least one of the plurality of sub tanks 30 is provided with a displacement sensor 50 that detects the displacement of the flexible member 32. The displacement sensor 50 is provided in the first sub tank 30 </ b> A located on the most upstream side among the plurality of sub tanks 30. On the other hand, the displacement sensor 50 is not provided in the second sub tank 30B located on the most downstream side. The displacement sensor 50 includes a lever member 51 that moves together with the pressure receiving member 42, and a photo interrupter 52 that is provided across a movement path of the lever member 51.

  As shown in FIG. 5, the lever member 51 is provided so as to be rotatable about the rotation shaft 53 with respect to the second plate 31 b. The lever member 51 is urged by the urging member 54 and maintains the contact state of the pressure receiving member 42 with the shaft portion 44. Note that the spring force of the biasing member 54 is negligibly small with respect to the spring force of the biasing member 41. The photo interrupter 52 has a light projecting unit and a light receiving unit arranged with the movement path of the tip of the lever member 51 interposed therebetween, and detects the displacement of the flexible member 32 by blocking or opening the optical axis. ing.

Next, the operation of the printer PRT configured as described above will be described with reference to FIGS.
FIGS. 8 and 9 are diagrams illustrating the relationship between the remaining amount of ink of the printer PRT and the pressure in the ink supply path 20 over time in the embodiment of the present invention. It should be noted that the numerical values such as pressure described below are examples, and may be changed as appropriate according to the type and model of the print job.

  In the example shown in FIGS. 8 and 9, the sub-tank 30 has a space volume of 3.9 g / piece, and can use two sub-tanks 30 to accommodate a maximum of 7.8 g of ink. Further, as described above, the spring force of the urging member 41A is set to 10.7 to 9.2N, and the spring force of the urging member 41B is set to 8.3 to 7.4N. Note that the spring force of the urging member 41 generates a pressurizing force that allows a predetermined amount of bubbles mixed in the ink supply path 20 to be expelled into the atmosphere through the tube forming the ink supply path 20 and the flexible member 32. Is set to Further, the ink jet head H is configured to be able to continue the print job by ensuring that the ink supply pressure to the self-sealing valve 22 is 3.0 kPa (kilopascal) or more.

  FIG. 8A shows the pressure in the ink supply path 20 during normal printing. The pressure pump 23 is driven to pressurize the ink cartridge CTR at 35.0 kPa. When there is sufficient ink in the ink cartridge CTR, the pressure of the ink pack 24 is 35.0 kPa, which is the same as that of the pressurizing pump 23. When the ink pack 24 is pressurized, the ink inside is supplied to the plurality of sub tanks 30 via the check valve 21. When the ink pack 24 is sufficiently pressurized, the internal volumes of the plurality of sub tanks 30 are also maximized.

  At this time, the pressure of the first sub tank 30A is 28.0 kPa, and the pressure of the second sub tank 30B is also 28.0 kPa. On the downstream side of the ink supply path 20, the pressure loss is affected, but the pressure in the ink chamber 33 is larger than the pressure received from the pressure applying means 40, and the flexible member 32 of the first sub tank 30 </ b> A, The flexible members 32 of the second sub tank 30B are not displaced in the direction in which the space volume of the ink chamber 33 is reduced. At this time, the ink supply pressure to the self-sealing valve 22 on the downstream side of the plurality of sub tanks 30 is 22.4 kPa, and 3.0 kPa or more at which the inkjet head H can operate normally is secured.

  FIG. 8B shows the pressure in the ink supply path 20 when the near ink end is detected during printing. If the remaining amount of ink in the ink cartridge CTR decreases during printing, the pressure of the ink pack 24 will not rise to 35.0 kPa even if the pressure pump 23 is driven at 35.0 kPa. When the pressure of the ink pack 24 is reduced to 25.0 kPa, the pressure of the plurality of sub tanks 30 on the downstream side of the ink pack 24 is reduced to 13.1 kPa due to pressure loss. At this time, in the first sub tank 30A, the pressure received from the pressure applying means 40 (the biasing member 41A) becomes larger than the pressure in the ink chamber 33, and the flexible member 32 increases the space volume of the ink chamber 33. Displace in the direction of reduction.

  The displacement sensor 50 detects the near ink end when the pressure of the ink pack 24 becomes 25.0 kPa or less, and the lever member 51 is lowered together with the flexible member 32 of the first sub tank 30A. When the optical axis of the photo interrupter 52 is opened, the near ink end is detected. At this time, in the other second sub tank 30B, the pressure in the ink chamber 33 is larger than the pressure received from the pressure applying means 40 (the urging member 41B), and the flexible member 32 is in the space of the ink chamber 33. Does not displace in the direction that reduces the volume.

  Even if a near ink end is detected during printing, the second sub-tank 30B contains ink necessary for completion of the currently executed job, and the remaining amount of the ink covers the necessary amount. For example, by using the ink (3.9 g) of the second sub tank 30B, it is possible to perform solid printing on the maximum size paper that can be printed by the printer PRT. When the near ink end is detected by the displacement sensor 50, the ink supply pressure to the self-sealing valve 22 is 7.5 kPa, and 3.0 kPa or more is ensured so that the inkjet head H can operate normally. When the near ink end is detected, the control device CONT displays a request for replacing the ink cartridge CTR on a display unit (not shown).

  FIG. 9A shows the pressure in the ink supply path 20 when the ink in the first sub tank 30A is used up after the near ink end is detected. When the remaining amount of ink in the ink cartridge CTR is further reduced, the pressure of the ink pack 24 is reduced to 10.5 kPa. When the pressure of the ink pack 24 decreases, the ink stops flowing from the ink pack 24 to the downstream side, and the downstream ink is consumed. Then, first, the flexible member 32 of the first sub tank 30A to which the maximum pressure is applied by the biasing member 41A is displaced to the vicinity of the bottom dead center, and almost all of the ink stored in the ink chamber 33 is discharged. Is consumed.

  At this time, in the second sub tank 30B, the flexible member 32 starts to be displaced in the direction of reducing the space volume of the ink chamber 33. In other words, in the vicinity of the pressure at which the flexible member 32 of the first sub tank 30A reaches the bottom dead center, the pressure received from the pressure applying means 40 (the urging member 41B) in the second sub tank 30B is the ink chamber. The pressure becomes larger than the pressure 33, and the flexible member 32 is displaced in the direction of reducing the space volume of the ink chamber 33. At this time, the pressure of the first sub tank 30A is 10.5 kPa, and the pressure of the second sub tank 30B is also 10.5 kPa. The ink supply pressure to the self-sealing valve 22 is 4.9 kPa at this time, and 3.0 kPa or more is ensured so that the inkjet head H can operate normally.

  FIG. 9B shows the pressure in the ink supply path 20 when the ink in the second sub tank 30B is used up. When the flexible member 32 is displaced to the bottom dead center, the pressure in the second sub tank 30B is 8.9 kPa. Further, the pressure of the first sub tank 30A is 8.9 kPa, and the pressure of the ink pack 24 is also 8.9 kPa. At this time, the ink supply pressure to the self-sealing valve 22 is 3.3 kPa, and 3.0 kPa or more is ensured so that the inkjet head H can operate normally. That is, the pressing force by the urging member 41B having the smallest urging force among the urging members 41 is larger than the pressure necessary for the inkjet head H to eject ink. Therefore, even if the remaining amount of ink in the ink cartridge CTR is low, the ink can be ejected from the inkjet head H by the pressure applied to the second sub tank 30B. Therefore, the stable ink until the ink in the ink supply path 20 runs out. Supply becomes possible.

  As described above, in the present embodiment, the pressure applying unit 40 is provided to apply different pressures to the flexible members 32 of the plurality of sub tanks 30. Thus, by positively applying pressure from the outside to the flexible members 32 of the plurality of sub tanks 30, the influence of the deformation characteristics of the flexible members 32 can be reduced, and the plurality of sub tanks 30 can be separated by time differences. Can be deformed. That is, in this embodiment, since the response of the flexible member 32 that deforms according to the pressure is performed by the highly accurate biasing member 41 (spring), variation in displacement of the plurality of sub tanks 30 can be suppressed. Accordingly, it is possible to reliably observe the temporal change of the pressure state in the ink supply path 20 and to appropriately grasp the replacement timing of the ink cartridge CTR from the detection of the near ink end.

In the present embodiment, a plate-shaped pressure receiving member 42 is provided, and the pressing area where the biasing member 41 presses the flexible member 32 is adjusted. By providing the plate-like pressure receiving member 42, the pressing area of the urging member 41 against the flexible member 32 can be kept constant, so that the influence of the deformation characteristics of the flexible member 32 can be reduced, and a plurality of The sub tank 30 can be reliably deformed with a time difference.
In the present embodiment, the pressure applying unit 40 adjusts the spring constant of the urging member 41 to apply different pressures to the flexible members 32 of the plurality of sub tanks 30. That is, it is not necessary to change the stroke and the pressurization area of the flexible member 32, all the sub-tanks 30 may have the same configuration, and parts can be diverted, which contributes to cost reduction.

  In the present embodiment, the pressure applying means 40 maximizes the pressure applied to the flexible member 32 of the first sub tank 30A located on the most upstream side among the plurality of sub tanks 30. The pressure applied to the flexible member 32 of the second sub tank 30B located on the downstream side of the sub tank 30A is reduced toward the downstream side. According to this configuration, the plurality of sub-tanks 30 can be deformed sequentially from the upstream side with a time difference, so that a change with time in the pressure state in the ink supply path 20 can be observed more reliably, and the ink cartridge CTR can be replaced. Know the timing. In addition, since the second sub tank 30B located on the most downstream side among the plurality of sub tanks 30 is finally displaced, the pressure loss when ink is ejected from the inkjet head H can be reduced as the ink end is approached. it can.

  In this embodiment, the displacement sensor 50 is provided in the first sub tank 30 </ b> A on the most upstream side among the plurality of sub tanks 30 to detect the displacement of the flexible member 32. Since the order of deformation of the plurality of sub-tanks 30 can be grasped by pressure adjustment by the pressure applying means 40, if one displacement sensor 50 is provided, it is possible to observe the temporal change of the pressure state in the ink supply path 20. Further, the first upstream sub tank 30A among the plurality of sub tanks 30 is closest to the ink cartridge CTR and has the highest responsiveness to the remaining amount of ink. Therefore, the remaining amount of ink in the ink cartridge CTR is accurately detected. it can. Further, after the displacement of the first sub tank 30A is detected, the job currently being performed can be continued with the ink stored in the second sub tank 30B on the downstream side where the pressure loss is small.

  In this embodiment, the ink supply path 20 upstream of the plurality of sub tanks 30 is provided with a check valve 21 that allows only the ink flow toward the downstream side, and is downstream of the plurality of sub tanks 30. The ink supply path 20 is provided with a self-sealing valve 22 that opens the ink supply path 20 when the downstream side reaches a predetermined negative pressure. According to this configuration, even when the job is continued by the ink stored in the plurality of sub tanks 30 by the pressurization by the urging member 41, the check valve 21 prevents the ink from flowing back to the ink cartridge CTR. The self-sealing valve 22 can reliably prevent ink leakage from the inkjet head H.

  Thus, according to the above-described embodiment, the ink jet head H that ejects ink supplied from the ink cartridge CTR that stores ink, and the ink supply path 20 that connects the ink cartridge CTR and the ink jet head H are connected. And the plurality of sub tanks 30 in which the ink is stored in the ink supply path 20 and the space volume in which the ink is stored is changed by the displacement of the flexible member 32, and the flexible members 32 of the plurality of sub tanks 30 are different. By adopting the configuration including the pressure applying means 40 for applying pressure, it is possible to obtain a printer PRT that can suppress variation in displacement of the sub tank 30 and prevent interruption of the job due to running out of ink.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

  For example, in the above-described embodiment, the configuration in which two subtanks 30 are provided has been described, but a configuration in which three or more subtanks 30 are provided may be employed.

  For example, in the above-described embodiment, a configuration in which the spring constant of the urging member 41 of the pressure applying unit 40 is adjusted to apply different pressures to the flexible members 32 of the plurality of sub tanks 30 will be described. However, even if the stroke until the urging member 41 displaces the flexible member 32 to the bottom dead center or the pressing area where the urging member 41 presses the flexible member 32 is adopted. Good.

  For example, in the above-described embodiment, the configuration in which different pressures are applied to the flexible members 32 of the plurality of sub tanks 30 using the biasing member 41 such as a spring or rubber has been described. The structure which substitutes with the other thing which can add a pressure may be sufficient. For example, you may employ | adopt the structure which provides a pressurization pump separately and pressurizes.

  For example, in the above-described embodiment, the configuration in which the displacement sensor 50 is provided only in the first sub tank 30A has been described. However, a configuration in which the displacement sensor 50 is provided in the second sub tank 30B may be employed, or both You may employ | adopt the structure provided in.

  Further, the liquid ejecting apparatus in the above-described embodiment may be a thermal jet printer or a line ink jet printer. Further, the present invention is not limited to a printer, and may be a device such as a copying machine or a facsimile.

  Further, the liquid ejecting apparatus may employ a configuration in which liquid other than ink is ejected or discharged. The present invention can be applied to various liquid ejecting apparatuses including a liquid ejecting head that ejects a minute amount of liquid droplets, for example. In addition, a droplet means the state of the liquid discharged from the said liquid ejecting apparatus, and shall also include what pulls a tail in granular shape, tear shape, and thread shape. The liquid here may be any material that can be ejected by the liquid ejecting apparatus. For example, it may be in a state in which the substance is in a liquid phase, such as a liquid with high or low viscosity, sol, gel water, other inorganic solvents, organic solvents, solutions, liquid resins, liquid metals (metal melts ) And a liquid as one state of a substance, as well as a material in which particles of a functional material made of a solid such as a pigment or metal particles are dissolved, dispersed or mixed in a solvent. A typical example of the liquid is ink as described in the above embodiment. Here, the ink includes general water-based inks and oil-based inks, and various liquid compositions such as gel inks and hot melt inks.

CTR Ink cartridge (liquid container) H Inkjet head (liquid ejecting head) PRT Printer (liquid ejecting apparatus) 20 Ink supply path (liquid supply path) 21 Check valve (one-way valve) 22 Self-sealing valve 23 Pressure pump ( Pressurizing means) 30 Sub tank 30A First sub tank (upstream sub tank) 30B Second sub tank (downstream sub tank) 32 Flexible member 36 Inlet 37 Outlet 40 Pressure applying means 41 Energizing member 41A Energizing Member (upstream biasing member) 41B biasing member (downstream biasing member) 42 pressure receiving member 50 displacement sensor

Claims (11)

A liquid ejecting head that ejects liquid supplied from a liquid container that contains liquid; and
A liquid supply path connecting the liquid container and the liquid jet head;
A plurality of sub-tanks in which liquid is stored in the liquid supply path, and a space volume in which the liquid is stored is changed by displacement of the flexible member;
Pressure applying means for applying different pressures to the flexible members of the plurality of sub-tanks,
A liquid ejecting apparatus. The pressure applying means has a plurality of biasing members that bias the flexible members of the plurality of sub-tanks, respectively.
The plurality of urging members are different in at least one of a spring constant, a stroke until the flexible member is displaced to the bottom dead center, and a pressurizing area for pressurizing the flexible member, respectively.
The liquid ejecting apparatus according to claim 1. The pressure applying means includes a plate-shaped pressure receiving member that adjusts a pressing area in which the biasing member presses the flexible member.
The liquid ejecting apparatus according to claim 2. The pressure applying means maximizes the pressure applied to the flexible member of the sub-tank located on the most upstream side among the plurality of sub-tanks, and allows the sub-tank located on the downstream side of the sub-tank. The pressure applied to the flexible member is reduced toward the downstream side,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. At least one of the plurality of sub-tanks is provided with a displacement sensor that detects the displacement of the flexible member.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The displacement sensor is provided in a sub tank located at least most upstream among the plurality of sub tanks.
The liquid ejecting apparatus according to claim 5. Each of the plurality of sub-tanks is provided with an introduction port for introducing a liquid at the lower portion and an outlet port for extracting the liquid at an upper portion,
The introduction port and the outlet port are opened in the same direction in the horizontal direction,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The plurality of sub-tanks are arranged from the lower part to the upper part in the gravity direction in order from the upstream one.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. The liquid supply path upstream of the plurality of sub tanks is provided with a one-way valve that allows only the flow of liquid toward the downstream side,
A self-sealing valve that opens the liquid supply path when the downstream side reaches a predetermined negative pressure is provided in the liquid supply path downstream of the plurality of sub tanks.
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. Having a pressurizing means for pressurizing the liquid container;
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. Of the pressures applied by the pressure applying means, the smallest pressure is larger than the supply pressure required for the liquid ejecting head to eject liquid,
The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus.

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