Liquid discharge device

Abstract

To appropriately reuse excess of applied liquid that is collected together with liquid to be discharged adhering to a nozzle surface.SOLUTION: A liquid discharge device comprises: a liquid discharge head 100 that discharges liquid I to be discharged, from a nozzle opening to a nozzle surface 101a; and liquid applying means 70 for applying liquid S to be applied, to the nozzle surface. The liquid applying means comprises: a storage part 74 that stores the liquid to be applied; a liquid applying member 73 for applying the liquid to be applied stored in the storage part to the nozzle surface; and a collecting member 75 that collects the liquid to be discharged adhering to the nozzle surface together with the liquid to be applied, into the storage part. The liquid to be applied is insoluble or poorly soluble to the liquid to be discharged, and has a specific gravity with respect to the liquid to be discharged being larger than one.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, there is known a device for ejecting liquid, which includes a liquid ejection head that ejects ejection liquid from nozzles opened in a nozzle face, and a liquid application means that applies the application liquid to the nozzle face.

[0003] For example, Patent Document 1 discloses a droplet ejection device (device that ejects liquid) equipped with a cleaning device that applies a cleaning liquid (application liquid) to the nozzle surface of a liquid ejection head and cleans ink adhering to the nozzle surface. In this cleaning device, the cleaning liquid applied from one end side of the nozzle surface is transported along the nozzle surface together with the ink on the nozzle surface, thereby cleaning the nozzle surface. The cleaning liquid transported to the other end side of the nozzle surface together with the ink is collected by a collection means and discarded without being reused. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in conventional devices that apply application liquid to a nozzle surface, there is a problem in that excess application liquid cannot be reused. Note that this problem is not limited to application liquid applied to the nozzle surface for the purpose of cleaning the nozzle surface, but can also occur in application liquid applied to the nozzle surface for other purposes. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a device for ejecting liquid, comprising a liquid ejection head which ejects an ejection liquid from a nozzle opening on a nozzle surface, and a liquid application means which applies an applied liquid to the nozzle surface, the liquid application means comprising a storage section which stores the applied liquid, a liquid application member which applies the applied liquid stored in the storage section to the nozzle surface, and a recovery member which recovers the ejection liquid adhering to the nozzle surface together with the applied liquid and returns it to the storage section, characterized in that the applied liquid is insoluble or poorly soluble in the ejection liquid and has a specific gravity greater than 1 relative to the ejection liquid. Effect of the Invention

[0006] According to the present invention, it is possible to appropriately reuse the surplus application liquid that is recovered together with the ejection liquid adhering to the nozzle surface. [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 coating unit in the image forming apparatus. [Figure 6] 5A to 5D are explanatory diagrams illustrating the application operation of the drying suppression liquid to the nozzle surface of the liquid ejection head by the application unit. [Figure 7] 13A to 13D are explanatory diagrams illustrating the configuration and operation of a coating unit according to a modified example in which a drying suppression liquid is applied to a nozzle face of a liquid ejection head by a coating nozzle. 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 coating unit 70 in this embodiment will be described. The application unit 70 in this embodiment is an example in which a drying suppression liquid (application liquid) is applied to the nozzle surface in order to suppress drying of the ink (ejection liquid) in the nozzles, but the purpose of applying the application liquid to the nozzle surface (application of the application liquid) is not particularly limited. Therefore, the application unit 70 in this embodiment may be used for other purposes, such as applying a cleaning liquid (application liquid) to the nozzle surface in order to clean the nozzle surface.

[0023] FIG. 5 is a perspective view showing a coating unit 70 of the present embodiment. The application unit 70 is composed of a unit drive section 71, a liquid tank 72 and a supply pipe 72a which constitute supply members, an application roller 73 as a liquid application member, a liquid pan 74 as a storage section, a cleaning blade 75 which is a cleaning member as a recovery member, and a waste liquid tank 76, a discharge pipe 76a and a valve 76b which constitute discharge members.

[0024] The unit driving section 71 moves the coating unit 70 along a unit movement direction B parallel to the sheet width direction. In the present embodiment, the coating unit 70 has a unit standby position on one side in the sheet width direction with respect to the transport area of ​​the continuous sheet 10. The unit driving section 71 reciprocates the coating unit 70 along the unit movement direction B parallel to the sheet width direction from the unit standby position to the opposite side of the transport area of ​​the continuous sheet 10 so as to pass near the nozzle faces 101a of the liquid ejection heads 100 constituting the head arrays 51K, 51C, 51M, and 51Y of the head unit 50.

[0025] The liquid tank 72 stores the drying suppression liquid S as the liquid to be applied to the nozzle surface 101a of the liquid ejection head 100. The drying suppression liquid S in the liquid tank 72 is appropriately replenished to the liquid pan 74 via the supply pipe 72a. In this way, the liquid tank 72 is appropriately replenished with the drying suppression liquid S that has been applied and consumed from within the liquid tank 72. The supply pipe 72a is a flexible pipe, and can maintain a connection between the liquid tank 72 and the liquid pan 74 even when the application unit 70 is moved by the unit drive section 71.

[0026] The application roller 73 is a liquid application member that applies the drying suppression liquid S to the nozzle surface 101a of the liquid ejection head 100, and is driven to rotate in the direction of the arrow C in Fig. 5. As shown in Fig. 5, the application roller 73 is disposed so that a portion of its circumferential surface is immersed in the drying suppression liquid S stored in the liquid pan 74. As a result, when the application roller 73 is driven to rotate, the drying suppression liquid S in the liquid pan 74 is pumped up and carried on the circumferential surface of the application roller 73.

[0027] The application roller 73 moves in the sheet width direction while keeping the peripheral surface of the application roller 73 in contact with the nozzle surface 101a, as a result of the application unit 70 moving in the unit movement direction B driven by the unit drive section 71. During this movement, the drying suppression liquid S on the peripheral surface of the application roller 73 that is rotated is applied to the nozzle surface 101a, and the drying suppression liquid S is applied to the nozzle surface 101a of the liquid ejection head 100. By the rotational drive of the application roller 73, excess drying suppression liquid S remaining on the peripheral surface portion that is in contact with the nozzle surface 101a is returned back into the liquid pan 74.

[0028] The liquid pan 74 is a storage unit that stores the drying suppression liquid S to be supplied to the circumferential surface of the application roller 73. The liquid pan 74 moves together with the application roller 73 along the unit movement direction B by the drive of the unit drive unit 71. The excess drying suppression liquid S remaining on the circumferential surface portion in contact with the nozzle surface 101a is collected into the liquid pan 74 by the rotational drive of the application roller 73. At this time, the ink (ejection liquid) I adhering to the nozzle surface 101a also adheres to the circumferential surface of the application roller 73 and is collected into the liquid pan 74. Therefore, the application roller 73 also functions as a recovery member that recovers the ink (ejection liquid) I adhering to the nozzle surface 101a together with the drying suppression liquid S into the liquid pan 74.

[0029] At this time, the drying suppression liquid S in this embodiment is insoluble or poorly soluble in the ink I, and has a specific gravity greater than 1 relative to the ink I. Therefore, even if the ink I and the drying suppression liquid S are mixed in the liquid pan 74, the ink I will settle in the drying suppression liquid S. As a result, as shown in FIG. 5, the drying suppression liquid S is stored separately in the upper part of the liquid pan 74, and the ink I is stored separately in the lower part.

[0030] The cleaning blade 75 is disposed inside the liquid pan 74 in a state of contacting the circumferential surface of the application roller 73. The cleaning blade 75 is a cleaning member that removes the ink (ejection liquid) I adhering to the circumferential surface of the application roller 73 from the nozzle surface 101a, from the application roller 73. The ink (ejection liquid) I removed by the cleaning blade 75 is collected in the drying suppression liquid S in the liquid pan 74. Therefore, the cleaning blade 75 functions as a recovery member that recovers the ink (ejection liquid) I adhering to the nozzle surface 101a together with the drying suppression liquid S into the liquid pan 74. Then, as described above, the ink (ejection liquid) I removed by the cleaning blade 75 settles in the drying suppression liquid S and is stored in the lower part of the liquid pan 74.

[0031] In this embodiment, the peripheral surface of the application roller 73 is cleaned by the cleaning blade 75, but other cleaning members such as a cleaning roller may also be used.

[0032] The waste liquid tank 76 stores the ink I discharged from the liquid pan 74. A discharge port is provided in the lower part or bottom of the liquid pan 74, and a valve 76b is provided at the discharge port, as shown in FIG. 5. When this valve 76b is opened, the ink I in the lower part or bottom of the liquid pan 74 is discharged from the discharge port through a discharge pipe 76a into the waste liquid tank 76. The discharge pipe 76a is a flexible tube, and can maintain a connection between the waste liquid tank 76 and the liquid pan 74 even when the application unit 70 is moved by the unit drive section 71.

[0033] 6(a) to (d) are explanatory diagrams illustrating the operation of the coating unit 70 coating the drying suppression liquid S onto the nozzle surface 101a of the liquid ejection head 100. FIG.

[0034] When performing a maintenance operation for the liquid ejection head 100, first, as shown in FIG. 6(a), the unit driver 71 of the application unit 70 is driven to move the application unit 70 (liquid pan 74) from the unit standby position along the unit movement direction B. In addition, the rotational drive of the application roller 73 is started to pump up and support the drying suppression liquid S in the liquid pan 74 on the circumferential surface of the application roller 73. Then, as shown in FIG. 6(b), the application roller 73 moves in the unit movement direction B while in contact with the nozzle surface 101a of the liquid ejection head 100, and the drying suppression liquid S on the application roller 73 is applied to the nozzle surface 101a of the liquid ejection head 100.

[0035] In this embodiment, since the application roller 73 comes into contact with the nozzle surface 101a of the liquid ejection head 100, the ink (ejection liquid) I adhering to the nozzle surface 101a of the liquid ejection head 100 adheres to the circumferential surface of the application roller 73. The ink I adhering to the circumferential surface of the application roller 73 is collected in the drying suppression liquid S in the liquid pan 74 as the application roller 73 is rotated. Furthermore, any ink I that remains on the circumferential surface of the application roller 73 and cannot be collected is scraped off by the cleaning blade 75 and collected in the drying suppression liquid S in the liquid pan 74.

[0036] Thereafter, when application of the drying suppression liquid S by the application roller 73 is completed as shown in Fig. 6(c), the unit drive section 71 of the application unit 70 moves the application unit 70 (liquid pan 74) back to the unit standby position along the unit movement direction B as shown in Fig. 6(d). When returning to the unit standby position, the application roller 73 moves along a movement route that does not contact the nozzle surface 101a of the liquid ejection head 100. Then, the application unit 70 is kept on standby at the unit standby position until the next application operation of the drying suppression liquid S is started.

[0037] By applying the drying suppression liquid S applied from the application roller 73 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) inside 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 the ink inside the nozzle 104 from drying out.

[0038] In particular, in this embodiment, the drying suppression liquid S applied to the nozzle surface 101a by the application roller 73 is non-volatile, and therefore can remain in a liquid state for a long period of time in the openings of the nozzles 104. Therefore, the application unit 70, which applies the non-volatile drying suppression liquid S to the nozzle surface 101a of the liquid ejection head 100, functions as a drying suppression means for suppressing drying of the ink in the nozzles 104 during non-operational periods of the image forming apparatus (periods during which liquid ejection operations are not performed).

[0039] 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 roller 73, 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.

[0040] In this embodiment, since the liquid application member is a contact type that applies the drying suppression liquid S by the application roller 73 that comes into contact with the nozzle surface 101a, the drying suppression liquid S can be applied by forcing it into the opening of the nozzle 104 that opens in the nozzle surface 101a. Therefore, the opening of the nozzle 104 can be covered with the drying suppression liquid S more reliably, and the drying of the ink in the nozzle 104 can be stably suppressed.

[0041] In addition, instead of the application roller 73 which is the liquid application member in this embodiment, another contact type liquid application member may be used, or a non-contact type liquid application member which applies the drying suppression liquid S to the nozzle surface 101a from a position away from the nozzle surface 101a may be used. An example of a non-contact type liquid application member is a non-contact type application nozzle which ejects and applies the drying suppression liquid S from a position away from the nozzle surface 101a of the liquid ejection head 100.

[0042] 7(a) to (d) are explanatory diagrams for explaining the configuration and operation of a coating unit 80 that applies the drying suppression liquid S to the nozzle surface 101a of the liquid ejection head 100 by the coating nozzle 83. FIG.

[0043] In this coating unit 80, when performing a maintenance operation for the liquid ejection head 100, first, as shown in Fig. 7(a), the unit drive section of the coating unit 80 is driven to move a liquid pan 84, in which a wiper blade 81 and a coating nozzle 83 are provided, along a unit movement direction B. The coating nozzle 83 ejects the drying suppression liquid S stored in the liquid pan 84.

[0044] At the timing when the coating nozzle 83 of the liquid pan 84 reaches the area facing the nozzle surface 101a of the liquid ejection head 100, the coating nozzle 83 starts ejecting the drying suppression liquid S. As a result, the drying suppression liquid S is applied from the coating nozzle 83 to the nozzle surface 101a of the liquid ejection head 100, as shown in FIG.

[0045] 7(b), the wiper blade 81 of the liquid pan 84 wipes the nozzle surface 101a of the liquid ejection head 100, thereby wiping away the ink (ejection liquid) I adhering to the nozzle surface 101a of the liquid ejection head 100 and also wiping away the excess drying suppression liquid S applied to the nozzle surface 101a. The ink I and drying suppression liquid S wiped away by the wiper blade 81 flow down the wiper blade 81 and are collected in the drying suppression liquid S in the liquid pan 84.

[0046] When the application nozzle 83 of the liquid pan 84 leaves the area facing the nozzle surface 101a of the liquid ejection head 100, ejection of the drying suppression liquid S from the application nozzle 83 is completed. Thereafter, as shown in FIG. 7(c), when wiping of the nozzle surface 101a of the liquid ejection head 100 by the wiper blade 81 is completed, the unit drive section of the application unit 80 moves the liquid pan 84 back to the unit standby position along the unit movement direction B as shown in FIG. 7(d). When returning to the unit standby position, the wiper blade 81 moves along a movement route that does not contact the nozzle surface 101a of the liquid ejection head 100. Then, the liquid pan 84 is kept on standby at the unit standby position until the next application operation and wiping operation of the drying suppression liquid S are started.

[0047] According to this embodiment, since the drying suppression liquid S is insoluble or poorly soluble in the ink I (ejection liquid) and has a specific gravity greater than 1 relative to the ink I, even if the ink I and the drying suppression liquid S are mixed in the liquid pan 74, the ink I will sink in the drying suppression liquid S. As a result, the drying suppression liquid S is stored separately in the upper part of the liquid pan 74, and the ink I is stored separately in the lower part. Therefore, even if the ink I and the drying suppression liquid S are mixed in the liquid pan 74, a separation mechanism for separating the drying suppression liquid S and the ink I is not required, and only the drying suppression liquid S in the liquid pan 74 can be applied to the nozzle surface 101a by the application roller 73, and the excess of the drying suppression liquid S can be separated from the ink I and reused.

[0048] Moreover, 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 ink in the nozzles 104 during non-operational periods of the image forming apparatus. Therefore, the conventional drying suppression means of capping the nozzle surface 101a with a capping member is not necessary. 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 corresponding to the number of liquid ejection heads 100 (the number of nozzle surfaces 101a) is required. 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.

[0049] In particular, since the drying suppression liquid S of this embodiment is insoluble or poorly soluble in ink (ejection liquid), the drying suppression liquid S blocking the opening of the nozzle 104 does not mix or does not easily mix with the ink, thereby obtaining the effect of blocking the opening of the nozzle 104 for a longer period of time.

[0050] In this embodiment, an example is shown in which the application operation of the drying suppression liquid S is performed at a predetermined timing for performing a maintenance operation, but the application operation may be performed at other timings when a maintenance operation is not performed. Also, since the application operation of the drying suppression liquid S does not necessarily have to be performed when performing a maintenance operation, the application operation of the drying suppression liquid S does not have to be performed when performing a maintenance operation.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The main scanning movement mechanism includes the guide member alone, and the supply mechanism includes the tube alone and the loading unit alone.

[0060] 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.

[0061] 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.

[0062] 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).

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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 an ejection liquid (e.g., ink I) from nozzles 104 opening in a nozzle surface 101a, and a liquid application means (e.g., application units 70, 80) that applies an application liquid (e.g., drying suppression liquid S) to the nozzle surface, the liquid application means including a storage section (e.g., liquid pan 74, 84) that stores the application liquid, a liquid application member (e.g., application roller 73 or application nozzle 83) that applies the application liquid stored in the storage section to the nozzle surface, and a recovery member (e.g., application roller 73 or wiper blade 81) that recovers the ejection liquid adhering to the nozzle surface together with the application liquid and into the storage section, the application liquid being insoluble or poorly soluble in the ejection liquid and having a specific gravity greater than 1 relative to the ejection liquid. There are known devices that apply an applied liquid to a nozzle surface for various purposes. For example, there is a device that applies a cleaning liquid (applied liquid) to a nozzle surface in order to clean the nozzle surface. In addition, as in the above-described embodiment, there is also a device that applies a drying suppression liquid (applied liquid) to the nozzle surface in order to suppress drying of the ink (ejection liquid) in the nozzle. Note that the purpose of applying the applied liquid to the nozzle surface (application of the applied liquid) is not particularly limited. In this aspect, the application liquid stored in the storage section is applied to the nozzle surface by the liquid application member, and the ejection liquid adhering to the nozzle surface is recovered by the recovery member together with the application liquid into the storage section, so that the excess application liquid adhering to the liquid application member, the nozzle surface, etc. is recovered into the storage section and reused as application liquid to be applied again to the nozzle surface. Here, in this embodiment, not only the applied liquid but also the ejection liquid is mixed in the storage section. Generally, if the ejection liquid in the storage section is applied to the nozzle surface together with the applied liquid, it becomes difficult to fully achieve the original purpose of applying the applied liquid to the nozzle surface. Therefore, it is necessary to suppress the ejection liquid in the storage section from being applied to the nozzle surface together with the applied liquid. The applied liquid in this embodiment is insoluble or poorly soluble in the ejection liquid, and has a specific gravity greater than 1 relative to the ejection liquid. Therefore, even if the ejection liquid and the applied liquid are mixed in the storage section, the ejection liquid will settle in the applied liquid. As a result, in the storage section, the applied liquid is stored separately at the top and the ejection liquid is stored separately at the bottom. Therefore, according to this embodiment, even if the ejection liquid and the applied liquid are mixed in the storage section, a separation mechanism for separating the applied liquid from the ejection liquid is not required, and only the applied liquid in the storage section can be applied to the nozzle surface by the liquid applying member, and the surplus applied liquid can be separated from the ejection liquid and reused.

[0068] [Second aspect] A second aspect is characterized in that in the first aspect, the liquid application member is a contact type (for example, an application roller 73) that contacts the nozzle face to apply the application liquid to the nozzle face. This makes it possible to stably and reliably apply a sufficient amount of the liquid to the nozzle surface.

[0069] [Third aspect] A third aspect is the second aspect, characterized in that the recovery member is a cleaning member (for example, a cleaning blade 75) that cleans the liquid applying member. When the application liquid is applied to the nozzle surface, the ejection liquid adhering to the nozzle surface adheres to the contact-type liquid application member. According to this aspect, the ejection liquid adhering to the liquid application member can be stably removed from the liquid application member and collected in the storage section. This makes it possible to prevent the ejection liquid adhering to the liquid application member from being supplied to the nozzle surface.

[0070] [Fourth aspect] A fourth aspect is the third aspect, characterized in that the cleaning member is a cleaning blade or a cleaning roller. According to this, the ejection liquid adhering to the liquid application member can be removed from the liquid application member with a simple configuration.

[0071] [Fifth aspect] The fifth aspect is characterized in that, in the first aspect, the liquid application member is a non-contact type (e.g., an application nozzle 83) that applies the application liquid to the nozzle face from a position away from the nozzle face. This suppresses problems caused by the ejection liquid adhering to the nozzle surface adhering to the liquid application member.

[0072] [Sixth aspect] The sixth aspect is characterized in that in any of the first to fifth aspects, the liquid application means is provided with a discharge member (e.g., a discharge pipe 76a and a valve 76b) that discharges the ejection liquid in the storage portion from the lower part of the storage portion. This makes it possible to discharge the ejection liquid that has accumulated in the storage portion from the storage portion.

[0073] [Seventh aspect] A seventh aspect is characterized in that in any of the first to sixth aspects, the liquid application means includes a supply member (for example, a liquid tank 72 and a supply pipe 72a) that supplies the application liquid to the storage section. According to this, it is possible to replenish the reservoir with the amount of liquid that has been applied to the nozzle surface and consumed.

[0074] [Eighth aspect] An eighth aspect is the invention according to any one of the first to seventh aspects, characterized in that the applied liquid is non-volatile. According to this aspect, since the applied liquid is non-volatile, the applied liquid applied to the nozzle surface can remain in a liquid state on the nozzle surface for a long period of time. As a result, for example, when the applied liquid (liquid for preventing drying) is applied to the nozzle surface of the liquid ejection head to prevent the ejection liquid from drying in the nozzles during non-operating periods (periods during which liquid ejection is not performed) of the image forming apparatus, the ejection liquid can be prevented from drying in the nozzles during non-operating periods without capping the nozzle surface with a capping member. [Explanation of symbols]

[0075] 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 70,80: Coating unit 71: Unit drive section 72: Liquid tank 72a: Supply pipe 73: Application roller 74: Liquid bread 75: Cleaning blade 76: Waste tank 76a: Discharge pipe 76b: Valve 81: Wiper blade 83: Application nozzle 84: Liquid bread 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: Unit movement direction S:Drying suppression liquid [Prior art documents] [Patent documents]

[0076] [Patent Document 1] JP 2012-224019 A

Claims

1. a liquid ejection head that ejects ejection liquid from nozzles that open on a nozzle surface; a liquid applying means for applying a liquid to the nozzle surface, the liquid applying means includes a storage section that stores the application liquid, a liquid applying member that applies the application liquid stored in the storage section to the nozzle surface, and a recovery member that recovers the ejection liquid adhering to the nozzle surface together with the application liquid into the storage section, A liquid ejecting device, wherein the application liquid is insoluble or poorly soluble in the ejection liquid and has a specific gravity of greater than 1 relative to the ejection liquid.

2. 2. The liquid ejection device according to claim 1, The liquid ejecting device is characterized in that the liquid applying member is of a contact type that applies the application liquid to the nozzle face by coming into contact with the nozzle face.

3. 3. The liquid ejection device according to claim 2, 2. The liquid ejecting device according to claim 1, wherein the recovery member is a cleaning member that cleans the liquid applying member.

4. 4. The liquid ejection device according to claim 3, The liquid ejecting device, wherein the cleaning member is a cleaning blade or a cleaning roller.

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

6. The liquid ejection device according to any one of claims 1 to 5, The liquid ejecting device according to claim 1, wherein the liquid applying means comprises a discharge member that discharges the ejection liquid in the storage portion from a lower portion of the storage portion.

7. The liquid ejection device according to any one of claims 1 to 5, The liquid ejecting device according to claim 1, wherein the liquid applying means includes a supply member that supplies the liquid to be applied to the reservoir.

8. The liquid ejection device according to any one of claims 1 to 5, A liquid ejecting device, wherein the applied liquid is non-volatile.

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