JP2016168739A - Liquid ejection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit drying of an interior space where a liquid discharge head is installed.SOLUTION: A printing device includes: a housing part defining the interior space R; a transportation mechanism for transporting a medium M so that the medium passes through the interior space R; the liquid discharge head installed in the interior space R to discharge ink to the medium M; and a second air-supply mechanism 62 installed downstream in a transportation direction of the medium M when viewed from the interior space R and jetting a humidified gas G2 to the medium M to supply the gas G2 into the interior space R.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a technique for ejecting a liquid such as ink onto a medium.

  Conventionally, there has been proposed a liquid ejection device in which a liquid ejection head that ejects liquid from a plurality of nozzles to a medium such as printing paper is installed in a space inside a casing (hereinafter referred to as “internal space”) (for example, Patent Document 1).

JP 2013-151110 A

  When the internal space in which the liquid discharge head is installed is dried, the liquid thickens inside the nozzle due to, for example, moisture evaporation, and as a result, there is a possibility that proper liquid discharge is hindered. For example, in a large-sized printing apparatus capable of large-format printing of an international standard A2 or larger size, as disclosed in Patent Document 1, ink on the surface of the medium is quickly dried by heating the medium discharged from the internal space. In the configuration in which the outside air heated by the heating mechanism can enter the internal space, the problem of drying of the internal space becomes particularly significant. In view of the above circumstances, an object of the present invention is to suppress drying of an internal space in which a liquid discharge head is installed.

  In order to solve the above-described problems, a liquid ejection apparatus according to the present invention includes a casing portion that forms an internal space, a transport mechanism that transports a medium so as to pass through the internal space, and a medium installed in the internal space. A liquid discharge head that discharges liquid to the internal space, and an air supply mechanism that is installed on the upstream side or the downstream side in the medium transport direction as viewed from the internal space, and supplies the humidified gas to the internal space by injecting the humidified gas to the medium; It comprises. In the above configuration, the humidification gas is supplied to the internal space by the air supply mechanism injecting the humidified gas onto the medium, so that it is possible to suppress the drying of the internal space where the liquid ejection head is installed. Further, since the humidified gas is injected into the medium from the air supply mechanism upstream or downstream in the medium conveyance direction as viewed from the internal space, there is an advantage that the entry of the external air into the internal space can be suppressed.

  In a preferred aspect of the present invention, the air supply mechanism injects the humidified gas from an injection port that is long in a direction intersecting the medium transport direction. In the above aspect, since the ejection port is formed in a long shape in a direction intersecting the medium conveyance direction, a layered airflow is formed by the gas ejected from the ejection port. Therefore, the above-described effect of suppressing the entry of outside air into the internal space is particularly remarkable.

  The liquid ejection apparatus according to a preferred aspect of the present invention includes an ejection port (hereinafter referred to as “second air supply mechanism” for convenience) through which the above-described air supply mechanism (hereinafter referred to as “second air supply mechanism”) injects humidified gas. A first air supply mechanism that injects gas into the medium from the first injection port on the side opposite to the internal space as viewed from the second injection port ”is provided. In the above configuration, since gas is injected from both the first injection port and the second injection port, compared to a configuration in which gas is injected only from the second injection port, the entry of outside air into the internal space is suppressed. The aforementioned effects are particularly prominent.

  In a preferred example of the aspect including the first air supply mechanism and the second air supply mechanism, the flow rate of the gas that the second air supply mechanism injects from the second injection port is the first air supply mechanism that injects from the first injection port. Less than the flow velocity of the gas. In the above aspect, since the flow velocity of the gas from the second injection port is lower than the flow velocity of the gas from the first injection port, a pressure is generated from the air flow at the second injection port toward the air flow at the first injection port. Therefore, there is an advantage that excessive supply of the humidified gas to the internal space is suppressed.

  A printing apparatus according to a preferred embodiment of the aspect including the first air supply mechanism and the second air supply mechanism controls at least one flow velocity of the gas injected by the first air supply mechanism and the gas injected by the second air supply mechanism. The control part which comprises. In the above aspect, since the flow velocity of at least one of the gas injected from the first injection port and the gas injected from the second injection port is controlled, the air flow from the second injection port is directed to the air flow of the first injection port. There is an advantage that the pressure (and hence the amount of the humidified gas entering the internal space) can be adjusted. In a further preferred aspect, a humidity detection unit that detects the humidity of the internal space is installed, and the control unit detects the gas that the first air supply mechanism injects and the second air supply mechanism according to the humidity detected by the humidity detection unit. Controls the flow rate of at least one of the gases injected by the. In the above aspect, since the amount of the humidified gas entering the internal space is adjusted according to the humidity of the internal space, there is an advantage that the internal space can be maintained at an appropriate humidity.

  In the configuration in which the medium is heated by the heating mechanism installed outside the internal space, the outside air heated by the heating mechanism can enter the internal space, and therefore, the drying of the internal space is particularly likely to occur. Therefore, the above-described aspects that can suppress the entry of outside air into the internal space are particularly effective.

  In a preferred aspect of the present invention, the first air supply mechanism is installed on the downstream side in the medium conveyance direction as viewed from the internal space, and gas is supplied in a direction inclined to the downstream side in the medium conveyance direction with respect to the downward direction in the vertical direction. Inject. In the above aspect, the gas is injected from the first injection port in a direction inclined to the downstream side with respect to the downward direction in the vertical direction. Therefore, there is an advantage that generation of turbulent flow due to gas collision with the surface of the medium M can be suppressed.

1 is an external view of a printing apparatus according to a first embodiment. It is sectional drawing of a printing apparatus. It is explanatory drawing of a gas injection mechanism. It is explanatory drawing of the injection outlet of a gas injection mechanism. It is explanatory drawing of the effect (reduction of color nonuniformity) of 1st Embodiment. It is explanatory drawing of the gas injection mechanism in 2nd Embodiment. It is explanatory drawing of the gas injection mechanism in 3rd Embodiment. It is explanatory drawing of the gas injection mechanism in 4th Embodiment.

<First Embodiment>
FIG. 1 is a configuration diagram of a printing system according to the first embodiment of the present invention. As illustrated in FIG. 1, the printing system according to the first embodiment includes a printing apparatus 100 and a control apparatus (host computer) 200. The control device 200 is realized by a personal computer, for example, and transmits a command to the printing apparatus 100 and image data of an image to be printed to the printing apparatus 100.

  The printing apparatus 100 according to the first embodiment is a liquid ejection apparatus that prints an image on the surface of the medium M by ejecting ink, which is an example of a liquid, onto the medium M. The medium M is a recording medium such as a printing paper or a film to be ejected with ink. The printing apparatus 100 according to the first embodiment is a printing apparatus (LFP: Large Format Printer) capable of printing on a medium M having a large size (for example, a paper width of about 128 inches) of A2 or more of the international standard, and is illustrated in FIG. As illustrated, the main body 12 and the legs 14 are provided. The main body 12 is a long structure in the X direction corresponding to the width direction of the medium M. A plurality of liquid containers (cartridges) 16 that store different types of ink are mounted on the main body 12. The leg part 14 supports the main body part 12 at a predetermined height. Wheels 142 for transportation are installed on the bottom surface of the leg portion 14. 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 100) is expressed as the Y direction.

  FIG. 2 is a cross-sectional view of the main body 12 (a cross section parallel to the YZ plane). As illustrated in FIG. 2, the main body portion 12 of the first embodiment includes a support body 22 and a housing portion 24. The aforementioned leg portion 14 is fixed to the support body 22, and the housing section 24 is pivotally supported by the support body 22 and can be opened and closed.

  The support 22 supports the medium M on a planar upper surface (hereinafter referred to as “transport surface”) 224. The casing 24 is a structure that forms a space R (hereinafter referred to as “internal space”) R inside the main body 12, and surrounds the space above the conveyance surface 224 (so-called platen) of the support 22. Specifically, the housing portion 24 includes a top surface portion 242 facing the transport surface 224 of the support 22 with a space therebetween, and a positive side in the Z direction (vertical) from the peripheral edge on the positive side in the Y direction of the top surface portion 242. A front surface portion 244 that protrudes downward in the direction) and a back surface portion 246 that protrudes from the peripheral edge on the negative side in the Y direction of the top surface portion 242 to the positive side in the Z direction. As illustrated in FIG. 2, the gap between the bottom surface of the back surface portion 246 and the transport surface 224 of the support 22 is a supply port QA for supplying the medium M to the internal space R, and supports the bottom surface of the front surface portion 244 and the support surface. A gap between the body 22 and the transport surface 224 is a discharge port QB for discharging the medium M from the internal space R. That is, the internal space R of the first embodiment communicates with the space outside the main body 12 via the supply port QA and the discharge port QB.

  As illustrated in FIG. 2, a suction mechanism 32 and a transport mechanism 34 are installed on the transport surface 224 of the support 22. The suction mechanism 32 brings the medium M into close contact with the transport surface 224 by sucking the gas (air) in the internal space R. That is, deformation of the medium M such as curling is reduced by the suction mechanism 32. Further, the internal space R is depressurized by suction by the suction mechanism 32.

  The transport mechanism 34 transports the medium M along the transport surface 224 in the Y direction (transport direction). The transport mechanism 34 of the first embodiment includes two transport rollers 342 whose rotation axes are parallel to the X direction, and a drive mechanism 344 such as a motor that rotates each transport roller 342. As illustrated in FIG. 2, the medium M positioned on the transport surface 224 of the support 22 is sandwiched between the two transport rollers 342 and moves in the Y direction with the rotation of the transport rollers 342. As understood from the above description, the medium M supplied to the internal space R from the supply port QA located on the upstream side of the transport mechanism 34 is transported in the Y direction on the surface of the transport surface 224 by the transport mechanism 34, The paper is discharged to the outside of the main body 12 from a discharge port QB located on the downstream side of the transport mechanism 34. That is, the transport mechanism 34 of the first embodiment transports the medium M so as to pass through the internal space R. Note that a transport mechanism 34 includes a paper feed mechanism that rotates a roll around which the belt-shaped medium M is wound and supplies the medium M to the supply port QA, and a winding mechanism that winds the medium M discharged from the discharge port QB. It is also possible to use as.

  As illustrated in FIG. 2, the liquid ejection head 42 and the carriage 44 are installed in the internal space R of the main body 12. Ink is supplied from the liquid container 16 to the liquid ejection head 42. The liquid ejection head 42 ejects ink onto the medium M in accordance with various commands and image data transmitted from the control device 200. As shown in an enlarged view in FIG. 2, the liquid ejection head 42 ejects ink from each of the plurality of nozzles N formed on the ejection surface 422 facing the transport surface 224 (or medium M) of the support 22. Specifically, the liquid ejection head 42 of the first embodiment includes a plurality of sets (not shown) of pressure chambers and piezoelectric elements corresponding to different nozzles N, and each of them is supplied with a drive signal corresponding to image data. By driving the piezoelectric element to vary the pressure in the pressure chamber, the ink filled in the pressure chamber is ejected from each nozzle N. The carriage 44 is a structure that accommodates and supports the liquid ejection head 42, and reciprocates repeatedly along the X direction by a driving mechanism (not shown) including a conveyance belt, a motor, and the like. In parallel with the conveyance of the medium M by the conveyance mechanism 34, the liquid ejection head 42 ejects ink onto the medium M, whereby an image is formed on the surface of the medium M.

  As illustrated in FIG. 2, the printing apparatus 100 according to the first embodiment includes a heating mechanism 52 and a heating mechanism 54 that are installed outside the main body 12 and heat the medium M. The heating mechanism 52 is installed on the downstream side in the transport direction of the medium M with respect to the internal space R, and promotes drying of the ink on the surface of the medium M by heating the medium M discharged from the discharge port QB. Specifically, the heating mechanism 52 includes a conveyance surface 522 that is inclined so as to be lower on the downstream side in the conveyance direction of the medium M (positive side in the Y direction), and a heating element 524 that heats the conveyance surface 522. The medium M transported along the transport surface 522 is heated. On the other hand, the heating mechanism 54 is installed at a position separated from the transport surface 522 and heats the medium M discharged from the discharge port QB. In FIG. 1, the heating mechanism 54 is not shown for convenience. In the first embodiment, a configuration in which the heating mechanism 54 is installed in the printing apparatus 100 is illustrated. However, a heating mechanism 54 that is separate from the printing apparatus 100 can be installed in the vicinity of the printing apparatus 100.

  As illustrated in FIGS. 1 and 2, the printing apparatus 100 according to the first embodiment includes a gas ejection mechanism 60. The gas injection mechanism 60 of the first embodiment is installed on the downstream side in the transport direction of the medium M when viewed from the internal space R. That is, the gas injection mechanism 60 is installed on the opposite side of the inner space R across the front surface portion 244 of the housing portion 24.

  FIG. 3 is an explanatory diagram of the gas injection mechanism 60. As illustrated in FIG. 3, the gas injection mechanism 60 injects the gas G (G1, G2) to the medium M discharged from the discharge port QB. A typical example of the gas G is air, but other gases such as an inert gas can also be used. The gas injection mechanism 60 of the first embodiment includes a first air supply mechanism 61 and a second air supply mechanism 62. The first air supply mechanism 61 injects the gas G1 from the injection port E1 to the medium M, and the second air supply mechanism 62 injects the gas G2 from the injection port E2 to the medium M.

  Specifically, as illustrated in FIG. 3, the first air supply mechanism 61 includes an air supply unit 612. The air supply unit 612 is a blower that supplies the gas G1 to the injection port E1. On the other hand, the second air supply mechanism 62 includes an air supply unit 622 and a humidification unit 624. The air supply unit 622 is a blower that supplies the gas G2 ′ to the ejection port E2, and the humidification unit 624 humidifies the gas G2 ′ that is supplied from the air supply unit 622 to the ejection port E2. A gas (humidified gas) G2 after being humidified by the humidifying unit 624 is jetted onto the medium M from the ejection port E2. As understood from the above description, the humidity of the gas G2 injected from the injection port E2 exceeds the humidity of the gas G1 injected from the injection port E1.

  FIG. 4 is a perspective view of the gas injection mechanism 60 according to the first embodiment as viewed from the positive side in the Z direction (medium M side). As illustrated in FIG. 4, the ejection port E <b> 1 and the ejection port E <b> 2 are formed on the surface of the gas ejection mechanism 60 facing the medium M. As understood from FIGS. 3 and 4, the injection port E <b> 2 is located between the injection port E <b> 1 and the internal space R on the downstream side of the internal space R. That is, the injection port E1 is located downstream of the injection port E2. As illustrated in FIG. 4, each of the ejection port E1 and the ejection port E2 is a long opening (slit) along the X direction intersecting the Y direction in which the medium M is conveyed. Therefore, the gas G1 ejected from the ejection port E1 and the gas G2 ejected from the ejection port E2 form a layered airflow (so-called air curtain) that proceeds to the positive side in the Z direction with the X direction as the width direction. That is, the air stream of the gas G1 and the air stream of the gas G2 are formed substantially parallel to each other in the Y direction.

  As illustrated in FIG. 3, the first air supply mechanism 61 injects the gas G1 in the direction D1 parallel to the Z direction, and the second air supply mechanism 62 also injects the gas G2 in the direction D2 parallel to the Z direction. As described above, the conveyance surface 522 of the heating mechanism 52 is inclined so as to become lower toward the downstream side, and the medium M is conveyed along the conveyance surface 522. Accordingly, the gas G1 ejected from the ejection port E1 changes in the traveling direction in the direction along the transport surface 522 on the surface of the medium M, and travels downstream along the transport surface 522. On the other hand, the gas G2 ejected from the ejection port E2 collides with the surface of the medium M, so that part of the gas G2 travels downstream and merges with the gas G1 and travels downstream. Advancing upstream along the surface of M and entering the internal space R from the outlet QB. That is, the internal space R is humidified by supplying the gas (humidified gas) G2 after being humidified by the humidifying unit 624 to the internal space R. As understood from the above description, the second air supply mechanism 62 of the first embodiment functions as an element that supplies the gas G2 to the internal space R by injecting the gas G2 to the medium M.

  As described above, in the first embodiment, the gas G (G1, G2) is injected into the medium M from the gas injection mechanism 60 installed on the downstream side in the transport direction of the medium M when viewed from the internal space R. The ingress of outside air into the internal space R is hindered by the gas G stream. Therefore, it is possible to suppress the drying of the internal space R due to the entry of outside air. In the first embodiment, a layered airflow (air curtain) is formed by injecting the gas G from the ejection port E1 and the ejection port E2 that are long in the X direction intersecting the conveyance direction of the medium M. Therefore, the effect of inhibiting the entry of outside air is particularly remarkable. In the first embodiment, since the first air supply mechanism 61 and the second air supply mechanism 62 form a plurality of layers of airflow, the internal space R is effectively compared with a configuration in which a single layer airflow is formed. Can prevent the outside air from entering. In the first embodiment, since the internal space R is depressurized by suction by the suction mechanism 32, there is a situation that outside air easily enters the internal space R through the discharge port QB. Considering the above circumstances, the first embodiment that can inhibit the entry of outside air into the internal space R is very effective.

  In addition, when the internal space R is dried, the ink thickens inside the nozzle N due to, for example, water evaporation, and as a result, there is a possibility that proper ink ejection is hindered. Especially in 1st Embodiment, the internal space R is easy to dry because the external air heated with the heating mechanism 52 or the heating mechanism 54 approachs the internal space R via the discharge port QB. Therefore, 1st Embodiment which can suppress the approach of the external air with respect to the internal space R by injection of the gas G with respect to the medium M is especially effective. Further, when the internal space R is excessively dried, there is a possibility that deterioration of each component (for example, the liquid ejection head 42 and the carriage 44) installed in the internal space R may progress. According to the first embodiment, since the drying of the internal space R is suppressed as described above, there is an advantage that deterioration of each component installed in the internal space R can be suppressed.

  In the first embodiment, the gas G2 is supplied to the internal space R by injecting the gas G2 after being humidified by the humidifying unit 624 onto the medium M. Therefore, it is possible to suppress the ingress of outside air into the internal space R by the gas G2 airflow and to humidify the internal space R by supplying the gas G2. That is, both the suppression of the entry of outside air into the internal space R and the humidification of the internal space R are realized by the gas G2. Therefore, it is possible to effectively suppress the drying of the internal space R as compared with the configuration in which the dried gas is jetted onto the medium M.

  As described above, in the first embodiment, since the drying of the internal space R is suppressed, the thickening of ink in each nozzle N of the liquid ejection head 42 is suppressed. Therefore, even when ink is ejected when a long time has elapsed since the last ink ejection, there is an advantage that the ink can be ejected under an appropriate condition (ejection amount or ejection direction). That is, there is an advantage that the performance of intermittently ejecting ink with a long interval can be maintained. In the configuration in which the internal space R is easy to dry, a moisturizing agent for suppressing ink thickening due to moisture evaporation can be added to the ink. In the first embodiment, as described above, drying of the internal space R (and hence thickening of the ink due to water evaporation) is suppressed, so that the amount of moisturizing agent added can be reduced (ideally omitted). It is. Further, since the ink on the surface of the medium M discharged from the discharge port QB is easily dried by reducing the amount of the moisturizer added, the heating amount (temperature) and the heating time by the heating mechanism 52 and the heating mechanism 54 are reduced. It is also possible. Therefore, there is an advantage that improvement in printing efficiency (number of printed pages per unit time) and reduction in power consumption of the heating mechanism 52 and the heating mechanism 54 are realized. Further, for example, when glycerin is added to the sublimation transfer ink as a humectant, the glycerin may be vaporized by the heating during the transfer to generate steam. In the first embodiment, since the amount of moisturizing agent added is reduced by suppressing the drying of the internal space R, there is also an advantage that the amount of glycerin vapor during the transfer of the sublimation transfer ink can be reduced.

  By the way, in the serial type printing apparatus 100 in which the liquid discharge head 42 reciprocates along the X direction, a time interval at which ink is sequentially discharged to a region of the medium M, particularly in the vicinity of the end in the width direction. However, it may differ depending on the direction of movement of the liquid ejection head 42. For example, FIG. 5 shows a time tA when ink is ejected to the area e of the medium M while the liquid ejection head 42 moves to the positive side in the X direction, and a process where the liquid ejection head 42 moves to the negative side in the X direction. The time point tB at which ink is ejected onto the area e of the medium M is shown. The interval TAB from the time point tA to the time point tB is shorter than the interval TBA from the time point tB to the time point tA. Therefore, the dry state at the time tB of the ink ejected at the time tA may be different from the dry state at the time tA of the ink ejected at the time tB. Due to the difference in the dry state, the characteristics (for example, hue and saturation) of the image printed on the surface of the medium M are different between the ink at the time tA and the ink at the time tB. It may be perceived as color unevenness in the vicinity of both ends. The color unevenness described above becomes more apparent as the ink drying speed in the internal space R increases (the difference in the drying state increases). According to the first embodiment, since the drying of the internal space R is suppressed as described above, there is an advantage that the color unevenness due to the difference in the dry state is reduced. The wider the reciprocating range of the liquid ejection head 42, the more likely the difference in dry state (and thus color unevenness due to the difference) occurs. Considering the above circumstances, the first embodiment that can reduce color unevenness by suppressing the drying of the internal space R is exceptionally the printing apparatus 100 capable of printing a medium-size medium M of A2 or larger as described above. It is suitable for.

Second Embodiment
A second embodiment of the present invention will be described. In addition, about the element which an effect | action and function are the same as that of 1st Embodiment in each form illustrated below, the code | symbol used by description of 1st Embodiment is diverted, and each detailed description is abbreviate | omitted suitably.

  FIG. 6 is an explanatory diagram of the gas injection mechanism 60 in the second embodiment. In the first embodiment, the configuration in which both the gas G1 and the gas G2 are injected in the directions (D1, D2) parallel to the Z direction is exemplified. As illustrated in FIG. 6, the first air supply mechanism 61 of the second embodiment has a direction D1 inclined by an angle θ on the downstream side of the conveyance of the medium M with respect to the positive side in the Z direction (downward in the vertical direction). The gas G1 is injected from the injection port E1. The angle θ is an acute angle (0 <θ <90 °). Specifically, the shape of the injection port E1 and the direction of blowing by the air supply unit 612 are selected so that the gas G1 is injected in the direction D1. On the other hand, the second air supply mechanism 62 injects the gas G2 in the direction D2 parallel to the Z direction as in the first embodiment.

  In the second embodiment, the same effect as in the first embodiment is realized. In the second embodiment, since the gas G1 is injected in the direction D1 inclined to the downstream side with respect to the Z direction, the traveling direction of the gas G1 reaching the vicinity of the surface of the medium M from the injection port E1 is the medium M. Changes smoothly on the surface. Therefore, there is an advantage that generation of turbulent flow due to collision of the gas G1 with the medium M can be suppressed.

<Third Embodiment>
FIG. 7 is an explanatory diagram of the gas injection mechanism 60 of the third embodiment. In the third embodiment, the flow velocity V1 of the gas G1 injected from the injection port E1 by the first supply mechanism 61 is different from the flow velocity V2 of the gas G2 injected from the injection port E2 by the second supply mechanism 62. Specifically, the flow rate V2 of the gas G2 is lower than the flow rate V1 of the gas G1 (V2 <V1). Accordingly, as indicated by the white arrow in FIG. 7, a pressure P is generated from the gas G2 air stream ejected from the ejection port E2 toward the gas G1 air stream ejected from the ejection port E1. The pressure P acts to draw the gas G2 injected from the injection port E2 toward the gas G1 (the positive side in the Y direction). Therefore, as compared with a configuration in which the flow velocity V1 and the flow velocity V2 are equal, the volume of the gas G2 injected from the injection port E2 that proceeds downstream with the gas G1 increases and enters the internal space R from the discharge port QB. The volume decreases.

  In the third embodiment, the same effect as in the first embodiment is realized. In the third embodiment, since the flow velocity V2 of the gas G2 injected from the injection port E2 is lower than the flow velocity V1 of the gas G1 injected from the injection port E1, the gas G2 humidified by the humidifying unit 624 is excessively contained inside. The possibility of entering the space R is reduced. Therefore, there is an advantage that excessive humidification of the internal space R can be suppressed. In addition, the structure of 2nd Embodiment which injects gas G1 to the direction D1 of angle (theta) with respect to Z direction may be applied also to 3rd Embodiment.

<Fourth embodiment>
FIG. 8 is an explanatory diagram of the gas injection mechanism 60 of the fourth embodiment. As understood from the description of the third embodiment, the pressure P increases as the difference (V1−V2) between the flow velocity V1 of the gas G1 injected from the injection port E1 and the flow velocity V2 of the gas G2 injected from the injection port E2 increases. Will increase. Therefore, as the flow velocity V2 is lower than the flow velocity V1 (that is, the pressure P is higher), the volume of gas G2 injected from the injection port E2 that enters the internal space R from the discharge port QB (hereinafter referred to as “entry amount”). ) Will decrease. In consideration of the above tendency, in the fourth embodiment, the amount of gas G2 entering the internal space R is adjusted by controlling the flow velocity V1 of the gas G1 and the flow velocity V2 of the gas G2. Specifically, the air supply unit 622 of the second air supply mechanism 62 variably sets the flow velocity V2 of the gas G2 according to a command from the control device 200, for example.

  As illustrated in FIG. 8, the humidity detector 70 is installed in the internal space R. The humidity detection unit 70 is a hygrometer that measures the humidity H of the internal space R. The control device 200 controls the second air supply mechanism 62 so that the flow velocity V2 of the gas G2 changes according to the humidity H of the internal space R detected by the humidity detector 70. Specifically, the control device 200 controls the air supply unit 622 of the second air supply mechanism 62 so that the flow velocity V2 increases (the difference from the flow velocity V1 decreases) as the humidity H decreases. Therefore, as the humidity H of the internal space R is lower, the pressure P decreases, and as a result, the amount of gas G2 entering the internal space R increases. As can be understood from the above description, it is possible to adjust the amount of gas G2 entered so that the humidity H of the internal space R approaches the target value.

  In the fourth embodiment, the same effects as those of the first embodiment and the third embodiment are realized. In the fourth embodiment, since the amount of gas G2 entering the internal space R is variably set by controlling the flow velocity V2 of the gas G2 according to the humidity H of the internal space R, the humidity H of the internal space R is appropriately set. There is an advantage that it can be adjusted. In the above example, the flow velocity V2 of the gas G2 is controlled. However, a configuration for controlling the flow velocity V1 of the gas G1 and a configuration for controlling both the flow velocity V1 and the flow velocity V2 may be employed. The lower the humidity H of the internal space R, the smaller the difference between the flow velocity V1 and the flow velocity V2 (and consequently the pressure P decreases and the amount of gas G2 entering the internal space R increases). A configuration in which at least one of them is controlled is preferable. In addition, the structure of 2nd Embodiment which injects gas G1 to the direction D1 of angle (theta) with respect to Z direction may be applied also to 4th Embodiment.

<Modification>
Each form illustrated above can be variously modified. Specific modifications are exemplified below. Two or more aspects arbitrarily selected from the following examples can be appropriately combined as long as they do not contradict each other.

(1) In each of the above-described embodiments, the configuration in which the gas injection mechanism 60 is installed on the downstream side in the conveyance direction of the medium M as viewed from the internal space R is exemplified, but instead of the above configuration (or with the configuration), the gas It is also possible to install the injection mechanism 60 on the upstream side of the internal space R. The gas injection mechanism 60 on the upstream side of the inner space R injects the gas G onto the medium M supplied to the supply port QA, thereby preventing the outside air from entering the internal space R from the supply port QA.

(2) In each of the above-described embodiments, as described with reference to FIG. 4, the gas injection mechanism 60 has exemplified the configuration including one injection port E1 and one injection port E2, but a plurality of injection ports A configuration in which E1 is arranged in the X direction and a configuration in which a plurality of injection ports E2 are arranged in the X direction may be employed.

(3) In 1st Embodiment, although the air supply part 612 of the 1st air supply mechanism 61 and the air supply part 622 of the 2nd air supply mechanism 62 were illustrated as a mutually separate element, the 1st air supply mechanism 61 is illustrated. It is also possible to share the air supply unit 612 with the second air supply mechanism 62. Specifically, the gas G1 sent from the air supply unit 612 of the first air supply mechanism 61 is branched into a first flow path on the injection port E1 side and a second flow path on the humidification unit 624 side, and the second supply The humidifying unit 624 of the air mechanism 62 supplies the gas G1 supplied to the second flow path to the ejection port E2 as the gas G2 by humidifying the gas G1. According to the above structure, since the air supply part 622 of the 2nd air supply mechanism 62 is abbreviate | omitted, there exists an advantage that the structure of the gas injection mechanism 60 is simplified.

(4) In each of the above-described embodiments, the printing apparatus 100 including both the first air supply mechanism 61 and the second air supply mechanism 62 has been exemplified, but one of the first air supply mechanism 61 and the second air supply mechanism 62 is illustrated. A configuration in which is omitted, or a configuration in which another air supply mechanism is added to the first air supply mechanism 61 and the second air supply mechanism 62 may be employed.

(5) The structure of the liquid discharge head 42 is changed as appropriate. For example, in each of the above-described embodiments, the piezoelectric liquid discharge head 42 using a piezoelectric element that imparts mechanical vibration to the pressure chamber is exemplified, but a heating element that generates bubbles in the pressure chamber by heating is used. It is also possible to adopt a thermal type liquid discharge head.

(6) The printing apparatus 100 exemplified in each of the above embodiments 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 100 ... Printing apparatus, 200 ... Control apparatus, 12 ... Main-body part, 14 ... Leg part, 16 ... Liquid container, 22 ... Support body, 224,522 ... Conveyance surface, 24 ... Housing part 242 …… Top surface portion, 244 …… Front surface portion, 246 …… Back surface portion, 32 …… Suction mechanism, 34 …… Transport mechanism, 342 …… Transport roller, 344 …… Drive mechanism, 42 …… Liquid discharge head, 44... Carriage 52... Heating mechanism 524... Heating element 54... Heating mechanism 60... Gas injection mechanism 61 ... First air supply mechanism 612 622. ... 2nd air supply mechanism, 624 ... humidification part, E1, E2 ... injection port.

Claims (3)

A housing forming an internal space;
A transport mechanism for transporting a medium so as to pass through the internal space;
A liquid discharge head that is installed in the internal space and discharges liquid to the medium;
A liquid discharge apparatus comprising: an air supply mechanism that is installed upstream or downstream in the conveyance direction of the medium as viewed from the internal space, and supplies the humidified gas to the internal space by injecting the humidified gas to the medium . The liquid ejecting apparatus according to claim 1, wherein the air supply mechanism ejects the humidified gas from an ejection port that is long in a direction intersecting a conveyance direction of the medium. The liquid ejection apparatus according to claim 1, further comprising a heating mechanism that is installed outside the internal space and heats the medium.

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