Liquid discharge device

Abstract

To downsize a liquid discharge device that has drying suppressing means for suppressing drying of liquid to be discharged in a nozzle in a non-operation period of time.SOLUTION: A liquid discharge device comprises: a liquid discharge head 100 that discharges liquid to be discharged, from a nozzle opened to a nozzle surface 101a; and drying suppressing means 70 for suppresses drying of the liquid to be discharged in the nozzle during a non-operation period of time. The drying suppressing means does not comprise a capping member for capping the nozzle surface. A liquid applying member 80 applies non-volatile liquid S for suppressing drying to the nozzle surface, so as to suppress drying of the liquid to be discharged in the nozzle during the non-operation period of time, without making the capping member cap the nozzle surface.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an apparatus for discharging liquid. [Background technology]

[0002] Conventionally, there is known a device for ejecting liquid, which includes a liquid ejection head that ejects ejection liquid from nozzles that open on a nozzle surface, and a drying suppression means that suppresses drying of the ejection liquid in the nozzles during non-operating periods.

[0003] For example, Patent Document 1 discloses a full-line type printing device (device for ejecting liquid) that includes a head array in which a plurality of liquid ejection heads are supported so as not to move in a direction parallel to the nozzle surface, and ejects liquid from the nozzles of each liquid ejection head onto a sheet material to perform printing. This printing device includes a maintenance unit (drying suppression means) that caps the nozzle surface of each liquid ejection head with a cap (capping member) to suppress drying of the liquid (ejection liquid) in the nozzle during non-operational periods. The maintenance unit is retracted to the downstream side of the head array in the sheet material conveying direction during the printing operation (operational period) of the printing device. When capping is performed during non-printing operations (non-operational periods), the head array rises, the maintenance unit moves below the head array, and each cap is moved to a position facing the nozzle surface of each liquid ejection head. After that, the head array descends, and the nozzle surface of each liquid ejection head is capped with a cap (capping member). Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional devices that prevent the ejection liquid inside the nozzles from drying by capping the nozzle surface with a capping member, there was a problem in that the device became large in size. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a liquid ejection device having a liquid ejection head that ejects ejection liquid from a nozzle opening on a nozzle surface, and a drying suppression means that suppresses the drying of the ejection liquid in the nozzle during non-operating periods, wherein the drying suppression means does not include a capping member that caps the nozzle surface, and is characterized in that it suppresses the drying of the ejection liquid in the nozzle during non-operating periods by applying a non-volatile drying suppression liquid to the nozzle surface by a liquid application member, without capping the nozzle surface with the capping member. Effect of the Invention

[0006] According to the present invention, in a device for ejecting liquid having a drying suppression means for suppressing drying of the ejection liquid in the nozzles during non-operational periods, it is possible to realize a smaller device size than before. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram illustrating an example of an image forming system according to an embodiment. [Diagram 2] 4 is an explanatory diagram illustrating a configuration of a head unit in the image forming apparatus of the image forming system, when the head unit is viewed from a normal direction of a sheet surface of a continuous sheet facing the head unit. FIG. [Diagram 3] FIG. 2 is an external perspective view illustrating a liquid ejection head constituting the head unit. [Figure 4] FIG. 2 is a cross-sectional explanatory diagram perpendicular to the nozzle row direction of the liquid ejection head. [Diagram 5] FIG. 2 is a perspective view showing a wiper / application unit in the image forming apparatus. [Figure 6] 6A to 6D are explanatory diagrams illustrating the application operation of the drying suppression liquid and the wiping operation on the nozzle surface of the liquid ejection head by the wiper / application unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described in which the present invention is applied to an image forming system including an image forming apparatus formed of an inkjet printer, which is a device that ejects liquid. It should be noted that the present invention is not limited to the type of liquid ejection head, and can be applied to any type of liquid ejection head, such as a piezoelectric type liquid ejection head, a bubble jet (registered trademark) type liquid ejection head, or an electrostatic type liquid ejection head.

[0009] FIG. 1 is a schematic diagram showing an example of an image forming system 1000 according to the present embodiment. The image forming system 1000 of this embodiment includes an unwinding device 1 that transports a continuous sheet 10, which is a continuous body serving as a recording material, an image forming device 5 that forms an image by ejecting liquid onto the continuous sheet 10 transported by the unwinding device 1, and a winding device 9 that discharges the continuous sheet 10 on which the image has been formed. The image forming device 5 includes a transport section 3 that transports the continuous sheet 10 transported by the unwinding device 1 to a head unit 50, a drying section 7 that dries the continuous sheet 10 on which the image has been formed, and the like.

[0010] The continuous sheet 10 is sent out from a sheet roll 11 of the unwinding device 1, transported by the rollers of the unwinding device 1, transport section 3, drying section 7, and winding device 9, and taken up by a print roll 91 of the winding device 9. The continuous sheet 10 is transported opposite to the head unit 50 in the image forming device 5, and an image is formed by the ejection liquid (image forming ink) ejected from the head unit 50.

[0011] In the head unit 50, for example, full line type head arrays 51K, 51C, 51M, and 51Y for four colors and liquid circulation mechanisms 200K, 200C, 200M, and 200Y corresponding to the head arrays 51K, 51C, 51M, and 51Y are arranged in this order from the upstream side in the sheet conveying direction A. Each of the head arrays 51K, 51C, 51M, and 51Y includes one or more liquid ejection heads, and ejects ejection liquids of black (K), cyan (C), magenta (M), and yellow (Y) onto the continuous sheet 10 being conveyed.

[0012] FIG. 2 is an explanatory diagram illustrating the configuration of the head unit 50, when the head unit 50 is viewed from the normal direction of the sheet surface of the continuous sheet 10 facing the head unit 50. As shown in FIG. 2, each of the head arrays 51K, 51C, 51M, and 51Y of this embodiment has liquid ejection heads 100 arranged in a staggered pattern on the base member 52. More specifically, the liquid ejection heads 100 arranged in each of the head arrays 51K, 51C, 51M, and 51Y are arranged so that the nozzle row direction coincides with the sheet width direction (direction perpendicular to the sheet conveying direction A). The sheet conveying direction positions of adjacent liquid ejection heads 100 are shifted alternately, and the sheet width direction positions of the nozzle rows of adjacent liquid ejection heads 100 are arranged so that they partially overlap each other.

[0013] FIG. 3 is an explanatory perspective view showing the appearance of the liquid ejection head 100 according to this embodiment. FIG. 4 is a cross-sectional explanatory diagram perpendicular to the nozzle row direction of the liquid ejection head 100 in this embodiment. The liquid ejection head 100 of this embodiment includes a structural portion in which a nozzle plate 101, a flow path plate 102, and a vibration plate member 103 are laminated and joined together. The liquid ejection head 100 also includes a piezoelectric actuator 111 as a pressure generating means for displacing a vibration region (vibration plate) 130 of the vibration plate member 103, a common liquid chamber member 120 that also serves as a frame member of the liquid ejection head 100, and a cover 129. The portion formed by the flow path plate 102 and the vibration plate member 103 is referred to as a flow path member 140.

[0014] The nozzle plate 101 is formed with a plurality of nozzles 104 for ejecting liquid.

[0015] The flow path plate 102 is formed with an individual liquid chamber 106 as a pressure chamber communicating with the nozzle 104 via a nozzle communication passage 105, a supply-side fluid resistance portion 107 communicating with the individual liquid chamber 106, and a through hole or groove portion serving as a liquid introduction portion 108 communicating with the supply-side fluid resistance portion 107. The nozzle communication passage 105 is a flow path communicating with each of the nozzle 104 and the individual liquid chamber 106. In addition, the liquid introduction portion 108 communicates with a supply-side common liquid chamber 110 via an opening 109 in the vibration plate member 103.

[0016] The diaphragm member 103 has a deformable vibration region 130 that forms the wall surface of the individual liquid chamber 106 of the flow path plate 102. The diaphragm member 103 has, for example, a two-layer structure (not limited to this), and is composed of a first layer that forms a thin portion and a second layer that forms a thick portion from the flow path plate 102 side, and the deformable vibration region 130 is formed in the first layer in a portion corresponding to the individual liquid chamber 106.

[0017] On the opposite side of the vibration plate member 103 from the individual liquid chamber 106, a piezoelectric actuator 111 including an electromechanical conversion element is disposed as a driving means (actuator means, pressure generating means) for deforming the vibration region 130 of the vibration plate member 103. The piezoelectric actuator 111 is, for example, formed by groove processing a piezoelectric member bonded onto a base member 113 by half-cut dicing to form a required number of columnar piezoelectric elements 112 in a comb shape at specified intervals. The piezoelectric elements 112 are bonded to protruding portions 130a which are island-shaped thick portions formed in the vibration region 130 of the vibration plate member 103. A flexible wiring member 115 is connected to the piezoelectric elements 112.

[0018] A supply side common liquid chamber 110 and a discharge side common liquid chamber 150 are formed in the common liquid chamber member 120. The supply side common liquid chamber 110 communicates with a supply port 171, and the discharge side common liquid chamber 150 communicates with a discharge port 181. The common liquid chamber member 120 is constituted by, for example, a first common liquid chamber member 121 and a second common liquid chamber member 122, and the first common liquid chamber member 121 is joined to the vibration plate member 103 side of the flow path member 140, and the second common liquid chamber member 122 is laminated and joined to the first common liquid chamber member 121.

[0019] The first common liquid chamber member 121 forms a downstream common liquid chamber 110A which is a part of the supply side common liquid chamber 110 which communicates with the liquid introduction portion 108, and a discharge side common liquid chamber 150 which communicates with a discharge flow path 151. The second common liquid chamber member 122 forms an upstream common liquid chamber 110B which is the remaining part of the supply side common liquid chamber 110. The flow path plate 102 is formed with a discharge flow path 151 which extends along the surface direction of the flow path plate 102 and communicates with each individual liquid chamber 106 via a nozzle communication path 105. The discharge flow path 151 communicates with the discharge side common liquid chamber 150.

[0020] In the liquid ejection head 100 of this embodiment, for example, by lowering the voltage applied to the piezoelectric element 112 from a reference potential (intermediate potential), the piezoelectric element 112 contracts, the vibration area 130 of the diaphragm member 103 is pulled, and the volume of the individual liquid chamber 106 expands. As a result, liquid flows into the individual liquid chamber 106. On the other hand, by increasing the voltage applied to the piezoelectric element 112 to expand the piezoelectric element 112 in the stacking direction and deform the vibration area 130 of the diaphragm member 103 in a direction toward the nozzle 104, the volume of the individual liquid chamber 106 contracts. As a result, the liquid in the individual liquid chamber 106 is pressurized, and the liquid is ejected from the nozzle 104.

[0021] The liquid in the individual liquid chamber 106 that is not ejected from the nozzle 104 is discharged from the discharge flow path 151 to the discharge side common liquid chamber 150, and is then supplied again from the discharge side common liquid chamber 150 to the supply side common liquid chamber 110 through an external circulation path. Note that the method of driving the head is not limited to the above example (pull-push shot), and pull shots, push shots, etc. can also be performed depending on the applied drive waveform.

[0022] Next, the configuration and operation of the wiper / application unit 70 in this embodiment will be described. FIG. 5 is a perspective view showing the wiper / application unit 70. As shown in FIG. The wiper / application unit 70 includes two wiper blades 71 as wiper members of the wiping means supported by a holder 72, and a holder drive unit 73 that drives the holder 72. The two wiper blades 71 are arranged on the holder 72 so as to be aligned along the sheet conveying direction A. Each wiper blade 71 is formed of, for example, a flexible resin plate member. Note that the wiper member is not limited to the configuration of the wiper blade 71, and may be a roller configuration or other configuration.

[0023] In the wiper / application unit 70 of this embodiment, one side in the sheet width direction with respect to the conveying area of ​​the continuous sheet 10 is set as a standby position (holder standby position) of the holder 72 (position of the holder 72 shown in FIG. 5). The holder driving unit 73 reciprocates the holder 72 along the holder movement direction B parallel to the sheet width direction from the holder standby position to the opposite side of the conveying area of ​​the continuous sheet 10 so as to pass near the nozzle faces 101a of the liquid ejection heads 100 constituting each of the head arrays 51K, 51C, 51M, and 51Y of the head unit 50.

[0024] In this embodiment, the holder 72 of the wiper / application unit 70 is provided with an application nozzle 80 as a liquid application member that applies non-volatile drying suppression liquid S to the nozzle surface 101a of the liquid ejection head 100. A liquid tank 81 that holds the drying suppression liquid S is connected to the application nozzle 80 via a flexible supply pipe 82, as shown in Fig. 5. This allows the application nozzle 80 to be appropriately replenished with the drying suppression liquid S from within the liquid tank 81 in an amount equal to the amount of drying suppression liquid S consumed by application.

[0025] The wiper / application unit 70 moves the holder 72 along the holder movement direction B by driving the holder drive section 73, so that the application nozzle 80 on the holder 72 moves along the sheet width direction so as to face the nozzle surface 101a of the liquid ejection head 100. Then, by applying the drying suppression liquid S from the application nozzle 80 during this movement, the drying suppression liquid S is applied to the nozzle surface 101a of the liquid ejection head 100.

[0026] During the movement of the holder 72, the wiper blade 71 on the holder 72 moves along the sheet width direction while contacting the nozzle surface 101a to which the drying suppression liquid S has been applied. This wipes away the ink (ejection liquid) and foreign matter adhering to the nozzle surface 101a of the liquid ejection head 100, and also wipes away the excess drying suppression liquid S applied to the nozzle surface 101a.

[0027] 6(a) to (d) are explanatory diagrams illustrating the application operation of the drying suppression liquid S and the wiping operation on the nozzle surface 101a of the liquid ejection head 100 by the wiper / application unit 70.

[0028] When performing a maintenance operation for the liquid ejection head 100, first, as shown in Fig. 6(a), the holder driving section 73 of the wiper / application unit 70 is driven to move the holder 72 along the holder movement direction B. Then, at the timing when the application nozzle 80 on the holder 72 reaches an area facing the nozzle surface 101a of the liquid ejection head 100, the application nozzle 80 starts ejecting the drying suppression liquid S. As a result, the drying suppression liquid S is applied from the application nozzle 80 to the nozzle surface 101a of the liquid ejection head 100, as shown in Fig. 6(b).

[0029] Also, as shown in FIG. 6(b), the wiper blade 71 on the holder 72 wipes the nozzle surface 101a of the liquid ejection head 100, thereby wiping away ink (ejection liquid) and foreign matter adhering to the nozzle surface 101a of the liquid ejection head 100 and also wiping away excess drying suppression liquid S applied to the nozzle surface 101a.

[0030] Then, ejection of the drying suppression liquid S from the application nozzle 80 is terminated at the timing when the application nozzle 80 on the holder 72 leaves the region facing the nozzle surface 101a of the liquid ejection head 100. Thereafter, as shown in FIG. 6(c), when wiping of the nozzle surface 101a of the liquid ejection head 100 by the wiper blade 71 is completed, the holder driving section 73 of the wiper application unit 70 moves the holder 72 back to the holder standby position along the holder movement direction B as shown in FIG. 6(d). When returning to the holder standby position, the wiper blade 71 moves along a movement route that does not contact the nozzle surface 101a of the liquid ejection head 100. Then, the holder 72 is kept on standby at the holder standby position until the next application operation and wiping operation of the drying suppression liquid S are started.

[0031] By applying the drying suppression liquid S applied from the application nozzle 80 to the nozzle surface 101a of the liquid ejection head 100, the opening of the nozzle 104 opening in the nozzle surface 101a can be covered with the drying suppression liquid S. This prevents the ink (ejection liquid) in the nozzle 104 (inside the liquid ejection head 100) from coming into contact with the outside air through the opening of the nozzle 104, and suppresses drying of the ink in the nozzle 104. Moreover, since the drying suppression liquid applied to the nozzle surface 101a by the application nozzle 80 is non-volatile, it can remain in a liquid state at the opening of the nozzle 104 for a long period of time. Therefore, the application nozzle 80 that applies the non-volatile drying suppression liquid to the nozzle surface 101a of the liquid ejection head 100 functions as a drying suppression means that suppresses drying of the ink in the nozzle 104 during a non-operational period (a period during which liquid ejection is not performed) of the image forming apparatus.

[0032] The application nozzle 80, which is the liquid application member in this embodiment, is of a non-contact type that ejects and applies the drying suppression liquid S from a position away from the nozzle surface 101a of the liquid ejection head 100, but the liquid application member is not limited to this. The liquid application member may be of a contact type that contacts the nozzle surface 101a to apply the drying suppression liquid S. As a specific example, the liquid application member may be of a contact type that contacts the nozzle surface 101a to apply the drying suppression liquid S. As a specific example, a coating roller or the like carrying the drying suppression liquid S on its circumferential surface may be brought into contact with the nozzle surface 101a to apply the drying suppression liquid S.

[0033] In this embodiment, the drying suppression liquid S may be applied to the nozzle surface 101a of the liquid ejection head 100 by the application nozzle 80, and then the drying suppression liquid S may be drawn into the nozzle 104 by the negative pressure in the liquid ejection head 100. Specifically, the voltage applied to the piezoelectric element 112 is lowered from the reference potential (intermediate potential) to contract the piezoelectric element 112, and the vibration region 130 of the vibration plate member 103 is pulled, increasing the negative pressure in the individual liquid chamber 106. As a result, the negative pressure in the nozzle 104 communicating with the individual liquid chamber 106 also increases, and the drying suppression liquid S applied to the nozzle surface 101a is drawn into the nozzle 104, so that the opening of the nozzle 104 can be covered with the drying suppression liquid S more reliably.

[0034] In this embodiment, the drying suppression liquid S on the nozzle surface 101a can be pushed into the openings of the nozzles 104 that open on the nozzle surface 101a by wiping the nozzle surface 101a to which the drying suppression liquid S has been applied with the wiper blade 71. Therefore, by wiping with the wiper blade 71, the openings of the nozzles 104 can be more reliably covered with the drying suppression liquid S, and the drying of the ink in the nozzles 104 can be stably suppressed.

[0035] According to this embodiment, the drying suppression liquid S is applied to the nozzle surface 101a of the liquid ejection head 100, thereby suppressing the drying of the ink in the nozzles 104 during non-operational periods of the image forming apparatus, and thus the conventional drying suppression means of capping the nozzle surface 101a with a capping member is not required. The capping member is required to be large enough to cover substantially the entire area of ​​the nozzle surface 101a to be capped, and the number of capping members is required according to the number of liquid ejection heads 100 (the number of nozzle surfaces 101a). Therefore, it is necessary to provide a space in the image forming apparatus for waiting capping members of such a size in the number corresponding to the number of liquid ejection heads, which makes the apparatus larger. In this embodiment, the advantage of being able to reduce the size of the apparatus is obtained compared to the conventional drying suppression means using a capping member.

[0036] The drying suppression liquid S of the present embodiment may be any liquid that is non-volatile and capable of covering the opening of the nozzle 104. However, it is preferable that the drying suppression liquid S is insoluble or poorly soluble in the ink (ejection liquid). If the drying suppression liquid S is insoluble or poorly soluble in the ink, the drying suppression liquid S blocking the opening of the nozzle 104 does not mix or is difficult to mix with the ink, thereby obtaining the effect of blocking the opening of the nozzle 104 for a longer period of time.

[0037] In this embodiment, the application operation of the drying suppression liquid S is performed at the timing of performing a predetermined maintenance operation (wiping operation), but it may be performed at other timings when the wiping operation is not performed. Also, since the application operation of the drying suppression liquid S does not necessarily have to be performed when the wiping operation is performed, the application operation of the drying suppression liquid S does not have to be performed when the wiping operation is performed.

[0038] In addition, since the specified maintenance operation is performed before the next print job is entered and the image forming apparatus goes into a standby state, the drying of the ink is suppressed by the drying suppression liquid S while the image forming apparatus is in a standby state (non-operating period). At this time, if the period during which the image forming apparatus is in a standby state (non-operating period) is short and there are no problems due to dried ink, it is not necessary to perform the application operation of the drying suppression liquid S. Therefore, if the length of the non-operating period is shorter than a predetermined period, it is possible to control so that the application operation of the drying suppression liquid S is not performed during the non-operating period. This makes it possible to suppress unnecessary consumption of the drying suppression liquid S.

[0039] Furthermore, the longer the period (non-operating period) in which the image forming apparatus is in a standby state, the greater the amount of drying suppression liquid S that can be applied to the nozzle surface 101a to suppress drying of the ink. Therefore, if the length of the non-operating period can be known in advance, such as when the time when the next print job will be performed is known in advance or when the time when the next print job will be performed can be estimated, the application amount (application amount) of the drying suppression liquid S applied during the non-operating period may be changed according to the length of the non-operating period. This makes it possible to suppress unnecessary consumption of the drying suppression liquid S.

[0040] In the present invention, the liquid used is not particularly limited as long as it has a viscosity and surface tension that allows it to be discharged from the head, but it is preferable that the viscosity is 30 [mPa·s] or less at room temperature and pressure, or by heating and cooling. More specifically, the liquid may be a solvent such as water or an organic solvent, a colorant such as a dye or a pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, an amino acid, a protein, or calcium, an edible material such as a natural dye, or a solution, suspension, or emulsion containing these. These may be used, for example, in inkjet inks, surface treatment liquids, and material liquids for three-dimensional modeling.

[0041] Energy sources for ejecting liquid include those that use piezoelectric actuators (laminated piezoelectric elements and thin-film piezoelectric elements), thermal actuators that use electrothermal conversion elements such as heating resistors, and electrostatic actuators consisting of a vibration plate and an opposing electrode.

[0042] A "liquid ejection unit" is a liquid ejection head integrated with functional parts and mechanisms, and includes a collection of parts related to ejecting liquid. For example, a "liquid ejection unit" includes a combination of a liquid ejection head and at least one of the following components: a head tank, a carriage, a supply mechanism, a maintenance and recovery mechanism, a main scanning movement mechanism, and a liquid circulation device. Here, integration includes, for example, a liquid ejection head and a functional part or mechanism fixed to each other by fastening, adhesion, engagement, etc., and one is held movably relative to the other. In addition, the liquid ejection head and the functional part or mechanism may be detachable from each other.

[0043] There are liquid ejection units in which the liquid ejection head and the head tank are integrated, and in which the two are integrated by being connected to each other via a tube, etc. Here, it is possible to add a unit including a filter between the liquid ejection head and the head tank of these liquid ejection units.

[0044] There are liquid ejection units in which the liquid ejection head and the carriage are integrated, and liquid ejection head, the carriage, and the main scanning movement mechanism are integrated, and there are liquid ejection units in which the liquid ejection head is movably held by a guide member that constitutes part of the scanning movement mechanism, and the liquid ejection head and the scanning movement mechanism are integrated.

[0045] In some liquid ejection units, a cap member that is part of a maintenance and recovery mechanism is fixed to a carriage on which a liquid ejection head is attached, integrating the liquid ejection head, carriage, and maintenance and recovery mechanism. In other liquid ejection units, a tube is connected to a liquid ejection head on which a head tank or a flow path part is attached, integrating the liquid ejection head and a supply mechanism. Liquid from a liquid storage source is supplied to the liquid ejection head via this tube.

[0046] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0047] In the present invention, the liquid ejection unit is described in combination with a liquid ejection head, but the liquid ejection unit also includes a head module including the above-mentioned liquid ejection head, or a head unit that is integrated with the above-mentioned functional components and mechanisms.

[0048] Devices that eject liquid include devices that are equipped with a liquid ejection head, a liquid ejection unit, a head module, a head unit, etc., and eject liquid by driving the liquid ejection head. Devices that eject liquid include not only devices that can eject liquid onto objects to which the liquid can adhere, but also devices that eject liquid into gas or liquid.

[0049] The device that ejects liquid can also include means related to the feeding, transporting, and discharging of objects to which liquid can be attached, other pre-processing devices, post-processing devices, etc. Examples of devices that eject liquid include an image forming device that ejects ink to form an image on a recording medium, and a three-dimensional modeling device (three-dimensional modeling device) that ejects modeling liquid onto a powder layer formed by forming a layer of powder in order to form a three-dimensional object (three-dimensional model).

[0050] Furthermore, the liquid ejection device is not limited to one that visualizes meaningful images such as letters and figures by ejecting liquid. For example, it also includes one that forms patterns that have no meaning in themselves and one that forms three-dimensional images.

[0051] The above-mentioned object to which liquid can adhere means an object to which liquid can adhere at least temporarily, and to which the liquid adheres and sticks or adheres and penetrates. Specific examples include recording media such as paper, film, and cloth, electronic substrates, electronic components such as piezoelectric elements, powder layers (powder layers), organ models, and test cells, and all objects to which liquid can adhere are included unless otherwise specified. The material to which liquid can adhere may be any material, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics, as long as the liquid can adhere even temporarily.

[0052] The liquid ejection device includes a configuration in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to only one of the moving objects. Specific examples include both a serial type device in which a liquid ejection head moves and a line type device in which a liquid ejection head does not move.

[0053] Other examples of devices that eject liquid include a treatment liquid application device that ejects a treatment liquid onto the surface of paper to apply the treatment liquid to the surface of the paper for purposes such as modifying the surface of the paper, and an injection granulation device that ejects a composition liquid in which raw materials are dispersed through a nozzle to granulate fine particles of the raw materials.

[0054] The above description is merely an example, and each of the following aspects provides unique effects. [First aspect] The first aspect is a device for ejecting liquid (e.g., image forming device 5) having a liquid ejection head 100 that ejects ejection liquid (e.g., ink) from nozzles 104 opening in a nozzle surface 101a, and a drying suppression means for suppressing the drying of the ejection liquid in the nozzles during non-operating periods, wherein the drying suppression means (e.g., wiper / application unit 70) does not include a capping member for capping the nozzle surface, and is characterized in that it suppresses the drying of the ejection liquid in the nozzles during the non-operating periods by applying a non-volatile drying suppression liquid S to the nozzle surface by a liquid application member (e.g., application nozzle 80) without capping the nozzle surface with the capping member. The drying suppression means in the conventional device suppresses the drying of the liquid to be ejected in the nozzles by capping the nozzle surface with a capping member. In such a conventional drying suppression means, a space is required for retracting the capping member from the nozzle surface and waiting so as not to interfere with the liquid ejection operation during the operation period (period during which the liquid ejection operation is performed) of the device that ejects the liquid. The capping member is required to be large enough to cover almost the entire area of ​​the nozzle surface to be capped, and the number of capping members corresponding to the number of liquid ejection heads (the number of nozzle surfaces) is required. Therefore, it is necessary to provide a space in the device for waiting capping members of such a size in the number corresponding to the number of liquid ejection heads. Therefore, the conventional device equipped with a capping member has a problem of increasing in size. The drying suppression means in this embodiment does not include a capping member for capping the nozzle surface. Instead, it includes a liquid applying member for applying a non-volatile drying suppression liquid to the nozzle surface, and when suppressing the drying of the ejection liquid in the nozzle during non-operational periods, the non-volatile drying suppression liquid is applied to the nozzle surface by the liquid applying member. As a result, the nozzle openings that open to the nozzle surface are covered by the drying suppression liquid applied to the nozzle surface, and the ejection liquid in the nozzle is prevented from coming into contact with the outside air through the nozzle openings. As a result, the drying of the ejection liquid in the nozzle is suppressed. Moreover, since the drying suppression liquid applied to the nozzle surface is non-volatile, it can remain in the nozzle openings in a liquid state for a long period of time. Therefore, it is possible to suppress the drying of the ejection liquid in the nozzle during non-operational periods without capping the nozzle surface with a capping member. Moreover, since the drying suppression liquid remains in a liquid state at the nozzle opening, when the non-operating period ends and the operating period begins and the ejection liquid is ejected from the nozzle, the drying suppression liquid can be quickly removed from the nozzle opening, for example, by being ejected together with the ejection liquid by the liquid ejection operation. Therefore, according to this aspect, a quicker transition from the non-operating period to the operating period can be achieved than in conventional devices that required an operation such as retracting the capping member to a standby space. Furthermore, since the liquid application member constituting the drying suppression means in this embodiment can be made smaller in size more easily than a conventional capping member, it is possible to realize a smaller device than before.

[0055] [Second aspect] A second aspect is the first aspect, characterized in that the liquid applicator is of a non-contact type that applies the drying suppression liquid from a position separated from the nozzle face. This suppresses problems caused by the ejection liquid or foreign matter adhering to the nozzle surface adhering to the liquid application member.

[0056] [Third aspect] A third aspect is the first aspect, characterized in that the liquid applicator is of a contact type that comes into contact with the nozzle face to apply the drying suppression liquid. This makes it possible to stably and reliably apply a sufficient amount of drying suppression liquid to the nozzle surface.

[0057] [Fourth aspect] A fourth aspect is characterized in that, in any of the first to third aspects, the drying suppression means applies the drying suppression liquid to the nozzle surface by the liquid application member, and then draws the drying suppression liquid into the nozzle by negative pressure within the liquid ejection head. This makes it possible to more reliably cover the nozzle opening with the drying suppression liquid S, and more stably suppress the drying of the ejection liquid inside the nozzle.

[0058] [Fifth aspect] The fifth aspect is characterized in that, in any of the first to fourth aspects, it has a wiping means (e.g., a wiper / application unit 70) that wipes the nozzle surface with a wiper member (e.g., a wiper blade 71) after the drying suppression liquid is applied to the nozzle surface by the liquid application member. This makes it possible to more reliably cover the nozzle opening with the drying suppression liquid S, and more stably suppress the drying of the ejection liquid inside the nozzle.

[0059] [Sixth aspect] A sixth aspect is any one of the first to fifth aspects, characterized in that the liquid ejection head is supported so as to be immovable in a direction parallel to the nozzle surface. In the case of a configuration in which the liquid ejection head is supported so as not to move in a direction parallel to the nozzle face (full-line type), the problem of the conventional device having a capping member becoming larger is prominent. Therefore, according to the present embodiment, a particularly useful effect can be obtained in such a case.

[0060] [Seventh aspect] A seventh aspect is any one of the first to sixth aspects, characterized in that the drying suppression liquid is insoluble or poorly soluble in the ejection liquid. According to this, the drying suppression liquid blocking the nozzle opening does not mix or does not mix easily with the ejection liquid, thereby obtaining the effect of blocking the nozzle opening for a longer period of time, and making it possible to suppress the drying of the ejection liquid in the nozzle for a longer period of time.

[0061] [Eighth aspect] The eighth aspect is characterized in that, in any of the first to seventh aspects, if the length of the non-operating period is shorter than a predetermined period, the drying suppression liquid is not applied by the liquid application member during the non-operating period. This can prevent unnecessary consumption of the drying suppression liquid.

[0062] [Ninth aspect] A ninth aspect is characterized in that, in any of the first to eighth aspects, the amount of the drying suppression liquid applied by the liquid application member during the non-operating period is changed depending on the length of the non-operating period. This can prevent unnecessary consumption of the drying suppression liquid. [Explanation of symbols]

[0063] 1: Unwinding device 3: Transport section 5: Image forming device 7:Drying section 9: Winding device 10: Continuous sheet 50: Head unit 51: Head Array 52: Base material 70: Wiper / application unit 71: Wiper blade 72: Holder 73: Holder drive unit 80: Application nozzle 81: Liquid tank 82: Supply pipe 100: Liquid ejection head 101: Nozzle plate 101a: Nozzle surface 102: Flow path plate 103: Diaphragm member 104: Nozzle 105: Nozzle connection passage 106: Individual liquid chamber 107: Supply side fluid resistance section 108: Liquid introduction section 109 :Aperture 110: Supply side common liquid chamber 111: Piezoelectric actuator 112: Piezoelectric element 113: Base material 120: Common liquid chamber member 130: Vibration area 140: Flow path member 150:Discharge side common liquid chamber 200:Liquid circulation mechanism 1000: Image forming system A: Sheet transport direction B: Holder movement direction S:Drying suppression liquid [Prior art documents] [Patent documents]

[0064] [Patent Document 1] JP 2020-138326 A

Claims

1. a liquid ejection head that ejects ejection liquid from nozzles that open on a nozzle surface; a drying suppression means for suppressing drying of the ejection liquid in the nozzle during a non-operating period, The drying suppression means does not include a capping member for capping the nozzle surface, and suppresses the drying of the ejection liquid in the nozzle during the non-operating period by applying a non-volatile drying suppression liquid to the nozzle surface using a liquid application member, without capping the nozzle surface with the capping member.

2. 2. The liquid ejection device according to claim 1, a nozzle face provided on the nozzle surface and configured to apply the drying suppression liquid from a position away from the nozzle face;

3. 2. The liquid ejection device according to claim 1, a nozzle surface provided on the nozzle face and configured to apply the drying suppression liquid to the nozzle face;

4. The liquid ejection device according to any one of claims 1 to 3, The drying suppression means is a liquid ejecting device characterized in that after the drying suppression liquid is applied to the nozzle surface by the liquid application member, the drying suppression liquid is drawn into the nozzle by negative pressure within the liquid ejection head.

5. The liquid ejection device according to any one of claims 1 to 3, a wiping means for wiping the nozzle surface with a wiper member after the drying suppression liquid is applied to the nozzle surface by the liquid application member;

6. The liquid ejection device according to any one of claims 1 to 3, a nozzle surface that faces the liquid ejection head and that faces the liquid ejection head;

7. The liquid ejection device according to any one of claims 1 to 3, A liquid ejecting device, wherein the drying suppression liquid is insoluble or poorly soluble in the ejection liquid.

8. The liquid ejection device according to any one of claims 1 to 3, A liquid ejecting device, comprising: a liquid applying member that applies the drying suppression liquid during a non-operating period when the length of the non-operating period is shorter than a predetermined period.

9. The liquid ejection device according to any one of claims 1 to 3, A liquid ejecting device, comprising: a liquid applying member that applies an amount of said drying suppression liquid during said non-operating period in accordance with a length of said non-operating period, and changes said amount of said drying suppression liquid applied by said liquid applying member during said non-operating period.

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