JP2017047536A - Liquid discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid discharge device which facilitates drying of a medium while inhibiting dryness of a discharge surface.SOLUTION: A liquid discharge device includes: a liquid discharge head 27 having a discharge surface 272 provided with nozzles for discharging a liquid to a medium 12; a transport mechanism which has a transport surface 282 facing the discharge surface and transports the medium along the transport surface; and a laminar flow formation mechanism 30 which supplies a first gas for inhibiting dryness of the discharge surface and a second gas for facilitating drying of the medium to an area between the discharge surface and the transport surface to form first laminar flow G1 of the first gas flowing along the discharge surface and second laminar flow G2 of the second gas flowing along the transport surface between the first laminar flow and the transport surface.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a technique for discharging a liquid such as ink.

  In a liquid ejection apparatus such as an ink jet printer, ink is ejected from a plurality of nozzles formed on the ejection surface of a liquid ejection head toward a medium such as printing paper. At this time, if the discharge surface of the liquid discharge head is dried, the ink thickens inside the nozzle due to, for example, water evaporation, and it may be difficult to discharge the ink properly. In order to suppress such drying of the ink on the ejection surface, for example, Patent Document 1 discloses a solution (water, ink solvent, oil, etc.) that inhibits ink drying between the ejection surface of the liquid ejection head and the medium. A gas containing a vaporized gas is supplied.

JP 2006-44021 A

  However, as in Patent Document 1, when a gas for suppressing ink drying is supplied between the ejection surface of the liquid ejection head and the medium, not only the drying of the ink on the ejection surface is suppressed, but also the medium Drying is suppressed even to the ink adhering to the ink. If the ink adhering to the medium is not dried, the inks may be mixed with each other and the image quality may be deteriorated. In view of the above circumstances, an object of the present invention is to promote drying of a medium while suppressing drying of a discharge surface of a liquid discharge head.

[Aspect 1]
In order to solve the above problems, a liquid ejection apparatus according to a preferred aspect (aspect 1) of the present invention includes a liquid ejection head having an ejection surface provided with a plurality of nozzles that eject liquid onto a medium, A transport mechanism that has a transport surface opposite the surface, transports the medium along the transport surface, a first gas that suppresses drying of the discharge surface between the discharge surface and the transport surface, and promotes drying of the medium A first laminar flow of the first gas that flows along the discharge surface, and a second gas that flows along the transport surface between the first laminar flow and the transport surface. A laminar flow forming mechanism that forms a second laminar flow. In the aspect 1, the laminar flow forming mechanism injects a first gas that suppresses drying of the discharge surface and a second gas that promotes drying of the medium between the discharge surface and the conveyance surface, to the discharge surface. A first laminar flow of the first gas flowing along the first laminar flow and a second laminar flow of the second gas flowing along the conveying surface between the first laminar flow and the conveying surface. While the drying of the discharge surface is suppressed by the first laminar flow, the drying of the medium conveyed along the conveying surface can be promoted by the second laminar flow. Thereby, drying of the liquid adhering to a medium can be accelerated | stimulated, suppressing drying of the liquid in the nozzle of a discharge surface.

[Aspect 2]
In a preferred example (Aspect 2) of Aspect 1, the second gas is at least one of high temperature and low humidity as compared with the first gas. The higher the gas temperature, the easier it is to promote drying, and the higher the gas humidity, the easier it is to control the drying. Conversely, the lower the temperature of the gas, the easier it is to suppress drying, and the lower the humidity of the gas, the easier it is to promote drying. In this regard, in aspect 2, the second gas is at least one of high temperature and low humidity as compared with the first gas. Therefore, if the second gas is high in temperature compared to the first gas, the first gas is the second gas. If the temperature is low compared to the gas and the second gas is low humidity compared to the first gas, the first gas is high humidity compared to the second gas. Thereby, drying of a medium can be accelerated | stimulated with 2nd gas, suppressing drying of an ejection surface with 1st gas.

[Aspect 3]
In a preferred example (Aspect 3) of Aspect 1 or Aspect 2, the liquid ejection head is mounted on a carriage that moves along the conveyance surface, and both the first laminar flow and the second laminar flow are parallel to the moving direction of the carriage. In the direction from one end of the carriage movement region to the other end. In the aspect 3, the liquid discharge head moves along the conveyance surface together with the carriage, and both the first laminar flow and the second laminar flow are formed in a direction parallel to the moving direction of the carriage. A first laminar flow and a second laminar flow can be formed between the discharge surface and the transport surface.

[Aspect 4]
In a preferred example of aspect 3 (aspect 4), the liquid discharge head is mounted on a carriage that moves along the transport surface, and both the first laminar flow and the second laminar flow are formed in a direction perpendicular to the moving direction of the carriage. Is done. In the aspect 4, the liquid discharge head moves along the conveyance surface together with the carriage, and both the first laminar flow and the second laminar flow are formed in a direction perpendicular to the moving direction of the carriage. A first laminar flow and a second laminar flow can be formed between the discharge surface and the transport surface.

[Aspect 5]
In a preferred example of the aspect 3 (aspect 5), the laminar flow forming mechanism is fixed to the carriage and moves together with the carriage. In the aspect 5, the laminar flow forming mechanism is fixed to the carriage and can form the first laminar flow and the second laminar flow between the ejection surface and the transport surface while moving together with the carriage.

[Aspect 6]
In a preferred example (Aspect 6) of Aspect 3 or Aspect 5, the controller includes a control device that controls the flow rates of the first gas and the second gas, and the control device includes the first gas and the second gas according to the moving direction of the carriage. To control the flow rate. The laminar flow forming mechanism moves relative to the conveyance surface together with the carriage while injecting the first gas and the second gas toward the X direction negative side. For this reason, in the first laminar flow and the second laminar flow, the relative flow velocity with respect to the conveyance surface changes depending on the moving direction of the carriage. For this reason, it may be difficult to maintain the laminar flow state of the first laminar flow and the second laminar flow depending on the moving direction of the carriage. In this respect, in aspect 6, since the flow rates of the first gas and the second gas are controlled according to the moving direction of the carriage, the two laminar flows of the first laminar flow and the second laminar flow are performed regardless of the moving direction of the carriage. This state can be easily maintained.

[Aspect 7]
In a preferred example (Aspect 7) of Aspect 1 or Aspect 2, the liquid ejection head is a line head that is long in a direction intersecting the transport direction of the medium, and the first laminar flow and the second laminar flow are liquids. It is formed in a direction perpendicular to the longitudinal direction of the ejection head. In aspect 7, since the first laminar flow and the second laminar flow are formed in a direction perpendicular to the longitudinal direction of the liquid ejection head, the first laminar flow and the second laminar flow are arranged between the ejection surface and the transport surface of the liquid ejection head. A two-layer flow is formed, whereby the drying of the medium conveyed along the conveyance surface by the second laminar flow can be promoted while the drying of the discharge surface is suppressed by the first laminar flow.

[Aspect 8]
In a preferred example (aspect 8) of any one of the aspects 1 to 7, the laminar flow forming mechanism includes a suction unit that sucks the first gas and the second gas that pass between the discharge surface and the transport surface. In the aspect 8, the laminar flow forming mechanism includes a suction unit that sucks the first gas and the second gas that have passed between the discharge surface and the transport surface, and thus the two-layer flow of the first laminar flow and the second laminar flow. The state of can be made more stable.

[Aspect 9]
In a preferred example (embodiment 9) of any one of the embodiments 1 to 8, the Reynolds number Re of the first laminar flow and the second laminar flow is Re <100. In the aspect 9, since the Reynolds number Re of the first laminar flow and the second laminar flow is Re <100, the state of the two laminar flows of the first laminar flow and the second laminar flow can be easily maintained. A good example of the liquid ejecting apparatus is a printing apparatus that ejects liquid onto a medium such as printing paper, but the use of the liquid ejecting apparatus according to the present invention is not limited to printing.

1 is a configuration diagram of a printing apparatus according to a first embodiment of the present invention. It is a figure for demonstrating the specific structural example of a laminar flow formation mechanism. It is a figure which shows the 1st modification of a laminar flow formation mechanism. It is a figure which shows the 2nd modification of a laminar flow formation mechanism. It is a figure which shows the 3rd modification of a laminar flow formation mechanism. It is operation | movement explanatory drawing of the laminar flow formation mechanism shown in FIG. It is a block diagram of the printing apparatus which concerns on 2nd Embodiment of this invention. It is operation | movement explanatory drawing of the laminar flow formation mechanism shown in FIG.

<First Embodiment>
First, an ink jet printing apparatus according to a first embodiment of the present invention will be described. FIG. 1 is a partial configuration diagram of a printing apparatus 10 according to the first embodiment of the present invention. A printing apparatus 10 illustrated in FIG. 1 is a suitable example of a liquid ejection apparatus that ejects ink, which is an example of a liquid, onto a medium 12 such as a printing paper. FIG. 2 is a diagram for explaining a specific configuration example of the laminar flow forming mechanism shown in FIG. In FIG. 2, the laminar flow forming mechanism 30 is shown in a block diagram so that the configuration can be easily understood. In the following description, the vertical direction (up and down direction) is expressed as the Z direction, and the direction perpendicular to the XZ plane (front and rear direction of the printing apparatus 10) is expressed as the Y direction.

  As shown in FIG. 1, the printing apparatus 10 includes a control device 22, a transport mechanism 24, a carriage 26, and a plurality of liquid ejection heads 27. The printing apparatus 10 is equipped with a liquid container (cartridge) 14 that stores ink. The control device 22 comprehensively controls each element of the printing apparatus 10. The conveyance mechanism 24 includes a conveyance roller 242 and the like, and conveys the medium 12 such as a printing paper in the Y direction under the control of the control device 22. Each liquid discharge head 27 is supplied with ink from the liquid container 14. Each liquid discharge head 27 discharges ink from a plurality of nozzles to the medium 12 under the control of the control device 22.

  Each liquid discharge head 27 is mounted on the carriage 26. The carriage 26 is a structure that accommodates and supports each liquid ejection head 27, and is crossed in the Y direction by a drive mechanism (not shown) including a conveyance belt and a motor under the control of the control device 22. Iteratively reciprocates along the direction. In parallel with the conveyance of the medium 12 by the conveyance mechanism 24 and the reciprocating reciprocation of the carriage 26, each liquid ejection head 27 ejects ink onto the medium 12, thereby forming a desired image on the surface of the medium 12.

  As shown in FIG. 2, the plurality of liquid ejection heads 27 include ejection surfaces 272 on which a plurality of nozzles N that eject ink to the medium 12 are formed. Each liquid discharge head 27 includes a plurality of sets (not shown) of pressure chambers and piezoelectric elements corresponding to different nozzles N. When a drive signal corresponding to the image data is supplied from the control device 22 to each liquid ejection head 27, each piezoelectric element is driven to vary the pressure in the pressure chamber, whereby each of the ink filled in the pressure chamber is changed. It discharges from the nozzle N. It is also possible to use a heat generating element that changes the pressure in the pressure chamber by generating bubbles in the pressure chamber by heating instead of the piezoelectric element.

  The medium 12 is transported while being supported by the transport surface 282 of the support 28. The support 28 is long in the reciprocating direction (X direction) of the carriage 26. The discharge surface 272 of each liquid discharge head 27 faces the transport surface 282 of the support 28. The carriage 26 reciprocates while a constant gap is always formed between the ejection surface 272 of each liquid ejection head 27 and the transport surface 282 of the support 28.

  In the present embodiment, the first laminar flow G1 that suppresses drying of the ejection surface 272 between the ejection surface 272 of each liquid ejection head 27 and the transport surface 282 of the support 28, and the first that promotes drying of the medium 12. A laminar flow forming mechanism 30 that forms a two-layer flow composed of the two-layer flow G2 is provided. The laminar flow forming mechanism 30 includes a first gas injection unit 32 that injects a first gas that suppresses drying of the discharge surface 272 and a second gas injection unit 34 that injects a second gas that promotes drying of the medium 12. Prepare.

  In the present embodiment, the laminar flow forming mechanism 30 is disposed at one end in the longitudinal direction of the transport surface 282 (X direction positive side), and the first gas and the first gas flow toward the other end of the transport surface 282 (X direction negative side). A case where two gases are injected is taken as an example. The arrangement of the laminar flow forming mechanism 30 is not limited to that shown in FIG. 1, and the laminar flow forming mechanism 30 is arranged at the other end in the longitudinal direction of the conveying surface 282 (X-direction negative side). You may make it inject the 1st gas and the 2nd gas toward one end (X direction positive side).

  As shown in FIG. 2, the first gas injection unit 32 injects the first gas toward the discharge surface 272 toward the negative side in the X direction between the discharge surface 272 and the transport surface 282. Thereby, the first laminar flow G1 of the first gas flowing along the discharge surface 272 is formed. On the other hand, the second gas injection unit 34 injects the second gas closer to the conveyance surface 282 toward the X direction negative side between the ejection surface 272 and the conveyance surface 282. Thereby, a second laminar flow G2 of the second gas flowing along the transport surface 282 is formed between the first laminar flow G1 and the transport surface 282.

  In the present embodiment, air having a high humidity and a low temperature is used as the first gas that suppresses drying of the ejection surface 272, whereas the humidity is low and the temperature is used as the second gas that promotes drying of the medium 12. Use high air.

  The first gas injection unit 32 shown in FIG. 2 humidifies the air into the first gas, and the second gas injection unit 34 heats the air into the second gas. That is, the first gas injection unit 32 shown in FIG. 2 includes an air supply unit 322, a humidification unit 324, and an injection port 326. The air supply unit 322 is a fan that supplies air toward the injection port 326, and the humidification unit 324 is a humidifier that humidifies the air supplied from the air supply unit 322 to the injection port 326. The injection port 326 has a long slit shape along the Y direction. The dimension in the longitudinal direction of the ejection port 326 is a length that includes at least the dimension in the Y direction of the ejection surface 272 of each liquid ejection head 27.

  In contrast, the second gas injection unit 34 illustrated in FIG. 2 includes an air supply unit 342, a heating unit 344, and an injection port 346. The air supply unit 342 is a fan that supplies air toward the injection port 346, and the heating unit 344 is a heater (heater) that heats the air supplied from the air supply unit 342 to the injection port 346. The injection port 346 has a long slit shape along the Y direction, like the injection port 326. The length of the ejection port 346 in the longitudinal direction is the same as that of the ejection port 326, and the ejection port 326 and the ejection port 346 are arranged so as to overlap in a plan view from the Z direction. In addition, the shape and arrangement | positioning of the injection port 326 and the injection port 346 are not restricted to what was mentioned above.

  According to such a configuration, the air of the first gas is humidified without being heated, whereas the air of the second gas is heated without being humidified. For this reason, 1st gas becomes low temperature and high humidity compared with 2nd gas, and 2nd gas becomes high temperature and low humidity compared with 1st gas. As a result, a first laminar flow G1 of a low temperature and high humidity first gas is formed on the discharge surface 272 side, and a second laminar flow G2 of a high temperature and low humidity second gas is formed on the transport surface 282 side. . As shown in FIGS. 1 and 2, the first laminar flow G1 and the second laminar flow G2 are formed without crossing from one end to the other end in the longitudinal direction (X direction) of the conveyance surface 282 along which the carriage 26 reciprocates. Is done. The drying of the medium 12 conveyed along the conveying surface 282 by the second laminar flow G2 can be promoted while suppressing the drying of the discharge surface 272 by the first laminar flow G1. Thereby, drying of the ink adhering to the medium 12 can be promoted while suppressing drying of the ink in the nozzles N of the ejection surface 272.

  If only the first gas of low temperature and high humidity is supplied between the discharge surface 272 and the transport surface 282 of the liquid discharge head 27, the first gas contacts both the discharge surface 272 and the transport surface 282. Will do. In this case, drying of the ink on the ejection surface 272 is suppressed, but drying of the ink attached to the medium 12 is also suppressed. If the ink adhering to the medium 12 is not dried, the inks may be mixed with each other and the image quality may be deteriorated. On the other hand, if only the high-temperature and low-humidity second gas is supplied between the discharge surface 272 and the transport surface 282 of the liquid discharge head 27, the second gas is transferred to the discharge surface 272 and the transport surface 282. You will be in contact with both. In this case, although the drying of the ink attached to the medium 12 can be promoted, the ink in the nozzle N on the ejection surface 272 is also dried. When the ink in the nozzle N on the ejection surface 272 is dried, the ink thickens inside the nozzle due to, for example, water evaporation, and it may be difficult to eject the ink properly. In this regard, in the present embodiment, the first gas flow (first laminar flow G1) on the ejection surface 272 side and the first gas flow on the conveyance surface 282 side are disposed between the ejection surface 272 and the conveyance surface 282 of the liquid ejection head 27. A two-layer flow of two gas flows (second laminar flow G2) is formed. Thus, the present embodiment is extremely effective in that it is possible to achieve both the suppression of drying of the ejection surface 272 and the promotion of drying of the medium 12.

  Further, since the laminar flow forming mechanism 30 shown in FIG. 1 forms the first laminar flow G1 and the second laminar flow G2 in a direction parallel to the moving direction of the carriage 26, even if the carriage 26 moves, the discharge surface A first laminar flow G1 and a second laminar flow G2 are formed between the 272 and the conveying surface 282.

  In the present embodiment, the first gas (first laminar flow G1) that suppresses drying of the discharge surface 272 is lower in temperature and humidity than the second gas, and the second gas (which promotes drying of the medium 12) ( Although the case where the second laminar flow G2) has a higher temperature and lower humidity than the first gas has been described, the present invention is not limited to this. The first gas may be either one of low temperature and high humidity than the second gas, and the second gas may be one of high temperature and low humidity than the first gas. In the present embodiment, as the first gas and the second gas, those in which air is humidified or heated are used, but the present invention is not limited to this. For the first gas, a gas containing a solution obtained by evaporating a solution (ink solvent, oil, etc.) that suppresses ink drying is used, and for the second gas, a solution that suppresses ink drying is included. No gas may be used. This also facilitates drying of the medium 12 transported along the transport surface 282 by the second laminar flow G2 while suppressing the drying of the ejection surface 272 by the first laminar flow G1.

  Moreover, the flow of the 1st laminar flow G1 and the 2nd laminar flow G2 can be stabilized by making Reynolds number Re of the 1st laminar flow G1 and the 2nd laminar flow G2 small. Specifically, it is preferable that the Reynolds numbers Re of the first laminar flow G1 and the second laminar flow G2 both satisfy Re <100. When the Reynolds number Re <100, the viscosity of the air increases, so that the first laminar flow G1 and the second laminar flow G2 can be made smooth and stable. Thereby, since the state of the two-layer flow of the first laminar flow G1 and the second laminar flow G2 is easily maintained, it is possible to more effectively achieve both the suppression of the drying of the discharge surface 272 and the promotion of the drying of the medium 12. it can. The Reynolds number Re can be expressed by the following mathematical formula (1).

  Re = vD / ν (1)

  In the above formula (1), v is the flow velocity of the first laminar flow G1 or the second laminar flow G2, ν is the kinematic viscosity coefficient of the first laminar flow G1 or the second laminar flow G2, and D is the discharge surface 272 and the conveyance surface 282. Is an equivalent diameter when the region where the first laminar flow G1 or the second laminar flow G2 flows is a rectangular cross section cut along the YZ plane, and can be calculated by, for example, the following mathematical formula (2).

  D = 4A / P (2)

  In Formula (2), A is a cross-sectional area of the region where the first laminar flow G1 or the second laminar flow G2 flows. P is the length of the wet side, and here, it is the length of the side where the first laminar flow G1 and the second laminar flow G2 are in contact with each other. Since the Reynolds number Re can be expressed as the above mathematical formula (1), for example, the Reynolds number Re can be adjusted by adjusting the flow velocity v of the first laminar flow G1 and the second laminar flow G2. In addition, the Reynolds number Re can be adjusted by reducing the speed of the carriage 26 or narrowing the gap between the ejection surface 272 and the transport surface 282.

  Moreover, although the case where the laminar flow formation mechanism 30 illustrated in FIG. 1 is configured by the first gas injection unit 32 and the second gas injection unit 34 is described as an example, it is not limited thereto. For example, as shown in the first modified example of FIG. 3, the laminar flow forming mechanism 30 includes a first gas and a second gas arranged at the other end (X direction negative side) in the longitudinal direction (X direction) of the transport surface 282. It may include a suction part 36 for sucking.

  Although the suction part 36 is arrange | positioned facing the 1st gas injection part 32 and the 2nd gas injection part 34, it does not show in figure, it is provided with the suction port which attracts | sucks 1st gas and 2nd gas, respectively. Each suction port is disposed to face the ejection port 326 and the ejection port 346, respectively. The suction unit 36 is configured by a fan that generates a suction force at each suction port, for example. According to this, the first laminar flow G1 and the second layer from the laminar flow forming mechanism 30 at one end (X direction positive side) in the longitudinal direction of the transport surface 282 to the suction portion 36 at the other end (X direction negative side). The state of the two-layer flow of the flow G2 can be further stabilized.

  The laminar flow forming mechanism 30 shown in FIG. 1 is an example in which the first laminar flow G1 and the second laminar flow G2 are formed in a direction parallel to the moving direction of the carriage 26. It is not limited to. For example, as shown in the second modified example of FIG. 4, the first laminar flow G1 and the second laminar flow G2 may be formed in a direction (Y direction) perpendicular to the moving direction of the carriage 26. In the laminar flow forming mechanism 30 shown in FIG. 4, similarly to the laminar flow forming mechanism 30 shown in FIG. 1, the first gas injection unit 32 that injects a first gas that suppresses drying of the discharge surface 272, and the medium 12. A second gas injection unit that injects a second gas that promotes drying.

  The laminar flow forming mechanism 30 shown in FIG. 4 is different from the laminar flow forming mechanism 30 shown in FIG. 1 in that the laminar flow forming mechanism 30 is arranged on one side in the Y direction (Y direction negative side) when viewed from the carriage 26. The first gas from the negative side in the Y direction toward the positive side across the carriage 26 from the jet port 326, 346, the point where the jet ports 326, 346 are formed long in the X direction, This is the point at which the second gas is injected. The dimension of the laminar flow forming mechanism 30 in the X direction is a dimension including the moving region of the carriage 26. According to the laminar flow forming mechanism 30 shown in FIG. 4, the first laminar flow G <b> 1 and the second laminar flow G <b> 2 can be formed in the entire moving region of the carriage 26. Also by this, drying of the medium 12 conveyed along the conveyance surface 282 by the second laminar flow G2 can be promoted while suppressing the drying of the discharge surface 272 by the first laminar flow G1. In the configuration of FIG. 4, a suction unit that sucks the first gas and the second gas that have passed between the ejection surface 272 and the transport surface 282 may be provided. Thereby, the state of the two-layer flow of the first laminar flow G1 and the second laminar flow G2 can be further stabilized.

  Moreover, although the case where the laminar flow formation mechanism 30 shown in FIG. 1 is fixed to one end (X direction positive side) of the transport surface 282 in the X direction is taken as an example, it is not limited thereto. For example, as shown in the third modified example of FIG. 5, the laminar flow forming mechanism 30 may be configured to be fixed to the carriage 26 and move together with the carriage 26. In FIG. 5, the laminar flow forming mechanism 30 is disposed on one side (positive side) in the X direction of the carriage 26, and the first gas and the second gas are injected toward the other side (negative side) in the X direction. The case is given as an example. The arrangement of the laminar flow forming mechanism 30 is not limited to that shown in FIG. 5, and the laminar flow forming mechanism 30 is arranged on the other side (negative side) of the X direction in the carriage 26, and one side of the X direction (positive side). The first gas and the second gas may be injected toward the side.

  6 is an operation explanatory view of the laminar flow forming mechanism 30 shown in FIG. 5, and is a schematic diagram of a VV cross section shown in FIG. As with the laminar flow forming mechanism 30 shown in FIG. 1, the laminar flow forming mechanism 30 shown in FIGS. 5 and 6 also includes a first gas injection unit 32 that injects a first gas that suppresses drying of the discharge surface 272, and a medium. 12 and a second gas injection unit 34 that injects a second gas that promotes drying. The laminar flow forming mechanism 30 shown in FIGS. 5 and 6 is different from the laminar flow forming mechanism 30 shown in FIG. 1 in that the first gas injection unit 32 and the second gas injection unit 34 are on one end side (X direction) of the carriage 26. This is a point that moves together with the carriage 26 while facing the medium 12 that is fixed along the conveyance surface 282 and fixed to the positive side.

  According to the laminar flow forming mechanism 30 having such a configuration, the first gas and the second gas are injected toward the positive side in the X direction while moving together with the carriage 26. Thereby, the 1st laminar flow G1 and the 2nd laminar flow G2 can be formed between the discharge surface 272 and the conveyance surface 282. Also by this, drying of the medium 12 conveyed along the conveyance surface 282 by the second laminar flow G2 can be promoted while suppressing the drying of the discharge surface 272 by the first laminar flow G1.

  The laminar flow forming mechanism 30 shown in FIGS. 5 and 6 jets the first gas and the second gas toward the X direction negative side, together with the carriage 26 on both the negative side and the positive side in the X direction. It moves relative to the transport surface 282. For this reason, with respect to the first laminar flow G1 and the second laminar flow G2, the relative flow velocity with respect to the transport surface 282 changes depending on the moving direction of the carriage 26. For this reason, the Reynolds number Re described above also changes. At this time, if the Reynolds number Re <100 cannot be maintained, the laminar flow state may be difficult to be maintained. Therefore, it is preferable that the control device 22 controls the flow rates of the first laminar flow G1 and the second laminar flow G2 so that the Reynolds number Re <100 according to the moving direction of the carriage 26.

  Specifically, when the flow directions of the first laminar flow G1 and the second laminar flow G2 are the same as the movement direction of the carriage 26 (when moving to the negative side in the X direction), the first laminar flow G1 and the second laminar flow The relative speed of the flow G2 with respect to the transport surface 282 is increased by the speed of the carriage 26. For this reason, when the carriage 26 moves in the same direction as the flow direction of the first laminar flow G1 and the second laminar flow G2, the jet velocity of the first gas and the second gas is reduced to reduce the first laminar flow. The speed with respect to the conveyance surface 282 of G1 and the 2nd laminar flow G2 is made low.

  On the other hand, when the flow directions of the first laminar flow G1 and the second laminar flow G2 are opposite to the moving direction of the carriage 26 (when moving to the positive side in the X direction), the first laminar flow G1 and the second laminar flow G2 The relative speed of the laminar flow G2 with respect to the conveying surface 282 is reduced by the speed of the carriage 26. For this reason, when the carriage 26 moves in the direction opposite to the flow direction of the first laminar flow G1 and the second laminar flow G2, the jet velocity of the first gas and the second gas is increased, and the first layer The velocity of the flow G1 and the second laminar flow G2 is increased. Thereby, according to the moving direction of the carriage 26, the flow velocity of the first laminar flow G1 and the second laminar flow G2 can be controlled so that the Reynolds number Re <100. For this reason, regardless of the moving direction of the carriage 26, it is possible to easily maintain the state of the two laminar flows of the first laminar flow G1 and the second laminar flow G2. In the configuration of FIG. 5 as well, a suction unit that sucks the first gas and the second gas that pass between the discharge surface 272 and the transport surface 282 may be provided. Thereby, the laminar flow state of the 1st laminar flow G1 and the 2nd laminar flow G2 can be stabilized more.

Second Embodiment
A second embodiment of the present invention will be described. In the first embodiment, the printing apparatus 10 including the serial head in which the carriage 26 on which the liquid discharge head 27 is mounted moves in the X direction is illustrated. However, in the second embodiment, the direction intersecting the conveyance direction of the medium 12 (here Then, the printing apparatus 10 including the liquid discharge head 27 configured as a line head that is long in the X direction) is illustrated. In the following exemplary embodiments, elements having the same functions and functions as those of the first embodiment are diverted using the same reference numerals used in the description of the first embodiment, and detailed descriptions thereof are appropriately omitted.

  FIG. 7 is a partial configuration diagram of the printing apparatus 10 according to the second embodiment of the present invention. FIG. 8 is an explanatory view of the operation of the laminar flow forming mechanism 30 shown in FIG. 7, and is a schematic view of the VI-VI cross section shown in FIG. The liquid ejection head 27 in the printing apparatus 10 shown in FIGS. 7 and 8 is a line head in which a plurality of ejection surfaces 272 are arranged in two rows along the X direction. Here, a case where a plurality of ejection surfaces 272 are arranged in a so-called staggered or zigzag manner is taken as an example. Note that the arrangement of the ejection surfaces 272 is not limited to this. Each discharge surface 272 includes a plurality of nozzles N and faces the transport surface 282 of the support 28.

  7 and 8, the laminar flow forming mechanism 30 is fixed to one end side (Y direction negative side) of the liquid discharge head 27 in the longitudinal direction, and the first gas and the first gas flow toward the other end side (Y direction positive side). The case where two gases are injected is taken as an example. The arrangement of the laminar flow forming mechanism 30 is not limited to this, and the laminar flow forming mechanism 30 is fixed to the other end side in the longitudinal direction of the liquid discharge head 27 (Y direction positive side) and is connected to one end side (Y direction). The first gas and the second gas may be injected toward the negative side.

  The laminar flow forming mechanism 30 shown in FIGS. 7 and 8 is similar to the laminar flow forming mechanism 30 shown in FIG. 1 and includes a first gas injection unit 32 that injects a first gas that suppresses drying of the discharge surface 272, and a medium. 12 and a second gas injection unit 34 that injects a second gas that promotes drying.

  The laminar flow forming mechanism 30 shown in FIGS. 7 and 8 is different from the laminar flow forming mechanism 30 shown in FIG. 1 in that the laminar flow forming mechanism 30 is one end side in the longitudinal direction of the liquid discharge head 27 (Y direction negative side). And from the ejection ports 326 and 346 from the negative side to the positive side in the Y direction across the liquid ejection head 27. The first gas and the second gas are respectively injected. The dimension of the laminar flow forming mechanism 30 in the X direction is a dimension including all of the ejection surfaces 272.

  Thereby, the 1st laminar flow G1 and the 2nd laminar flow G2 can be formed in each discharge surface 272 whole. According to the second embodiment having such a configuration, the first laminar flow G1 suppresses drying of the ejection surface 272 over the entire ejection surfaces 272, and the second laminar flow G2 conveys along the conveyance surface 282. Drying of the medium 12 to be performed can be promoted. In the second embodiment, a suction unit that sucks the first gas and the second gas passing between the ejection surface 272 and the transport surface 282 may be provided. Thereby, the state of the two-layer flow of the first laminar flow G1 and the second laminar flow G2 can be further stabilized.

  The printing apparatus 10 exemplified in the first embodiment and the second embodiment described in detail above can be employed in various apparatuses such as a facsimile apparatus and a copying machine in addition to apparatuses dedicated to printing. However, the use of the liquid ejection apparatus of the present invention is not limited to printing. For example, a liquid discharge device that ejects a solution of a color material is used as a manufacturing device that forms a color filter of a liquid crystal display device. In addition, a liquid discharge apparatus that ejects a solution of a conductive material is used as a manufacturing apparatus that forms wiring and electrodes of a wiring board.

DESCRIPTION OF SYMBOLS 10 ... Printing apparatus, 12 ... Medium, 14 ... Liquid container, 22 ... Control apparatus, 24 ... Conveyance mechanism, 242 ... Conveyance roller, 26 ... Carriage, 27 ... Liquid discharge head, 272 ... Discharge surface, 28 ... Support body, 282 DESCRIPTION OF SYMBOLS ... Conveyance surface, 30 ... Laminar flow formation mechanism, 32 ... 1st gas injection part, 322 ... Air supply part, 324 ... Humidification part, 326 ... Injection port, 34 ... 2nd gas injection part, 342 ... Air supply part, 344 ... heating section, 346 ... injection port, 36 ... suction section, N ... nozzle.

Claims (9)

A liquid ejection head having an ejection surface provided with a plurality of nozzles for ejecting liquid to the medium;
A transport mechanism having a transport surface facing the discharge surface, and transporting the medium along the transport surface;
The first gas that suppresses drying of the discharge surface and the second gas that promotes drying of the medium are injected between the discharge surface and the transport surface, and flow along the discharge surface. A laminar flow forming mechanism for forming a first laminar flow of the first gas, and a second laminar flow of the second gas flowing along the transport surface between the first laminar flow and the transport surface; Comprising
Liquid ejection device. The second gas is at least one of high temperature and low humidity compared to the first gas.
The liquid ejection device according to claim 1. The liquid discharge head is mounted on a carriage that moves along the transport surface;
The first laminar flow and the second laminar flow are both formed in a direction parallel to the moving direction of the carriage.
The liquid ejection apparatus according to claim 1 or 2. The liquid discharge head is mounted on a carriage that moves along the transport surface;
The first laminar flow and the second laminar flow are both formed in a direction perpendicular to the moving direction of the carriage.
The liquid ejection device according to claim 3. The laminar flow forming mechanism is fixed to the carriage and moves together with the carriage;
The liquid ejection device according to claim 3. A control device for controlling the flow rates of the first gas and the second gas;
The control device controls flow rates of the first gas and the second gas according to a moving direction of the carriage;
The liquid ejection apparatus according to claim 3 or 5. The liquid discharge head is a line head that is long in a direction intersecting the transport direction of the medium,
The first laminar flow and the second laminar flow are formed in a direction perpendicular to the longitudinal direction of the liquid discharge head.
The liquid ejection apparatus according to claim 1 or 2. The laminar flow forming mechanism includes a suction unit that sucks the first gas and the second gas that pass between the discharge surface and the transport surface.
The liquid ejection apparatus according to claim 1. The Reynolds number Re of the first laminar flow and the second laminar flow is Re <100.
The liquid ejection device according to claim 1.

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