Liquid ejection device

Abstract

To reduce variation in negative pressure between heads.SOLUTION: A plurality if discharging units 33A-33E including a head unit 200 and a sub tank 300 are arranged around a drum 31, and the discharging unit 33C is arranged in a direction of a perpendicular line (a vertical direction) passing on a center of the drum 31. The discharging units 33A, 33B, 33D and 33E are arranged to incline at a predetermined angle θ with the discharging unit 33C as a reference, and contents of the sub tank 300 are made different in accordance with the inclination angles of the discharging units 33A, 33B, 33D and 33E.SELECTED DRAWING: Figure 9

Description

[Technical field]

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

[0002] There are devices that eject liquids, such as printing devices, that have heads that eject multiple liquids arranged at an angle around a drum that transports sheet material and are equipped with a subtank (liquid storage container) that temporarily stores the liquid to be supplied to the heads.

[0003] Conventionally, a method is known in which the height of a sub-tank is varied depending on the inclination of the head, thereby making the head head difference between the sub-tank and the head approximately the same, thereby reducing the variation in negative pressure applied to the head (Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-209844 A Summary of the Invention [Problem to be solved by the invention]

[0005] As mentioned above, if the sub-tank that temporarily stores the liquid to be supplied to the head is tilted in the same way as the head, the liquid level in the tank will differ depending on the degree of tilt of the sub-tank. This causes a problem of variation in the head head difference between the head and the sub-tank, which in turn causes variation in negative pressure between each head.

[0006] The present invention has been made in consideration of the above problems, and has an object to reduce the variation in negative pressure between heads. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention Claim 1 The liquid ejecting device according to the present invention comprises: A plurality of heads for ejecting liquid; a plurality of sub-tanks each containing liquid to be supplied to each of the plurality of heads; the plurality of heads and the plurality of sub-tanks are disposed at an angle with respect to a vertical direction, The sub-tank is The liquid level detecting device has an upper limit detecting means for detecting an upper limit position of the remaining liquid level, and a lower limit detecting means for detecting a lower limit position of the remaining liquid level, The sub-tank of the head having a relatively large inclination angle has a larger distance between the upper limit position and the lower limit position than the sub-tank of the head having a relatively small inclination angle. The composition was as follows.

[0008] According to the present invention, it is possible to reduce the variation in negative pressure between heads. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic explanatory diagram of a printing apparatus as a liquid ejecting apparatus according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram of a main part of a printing unit of the printing device. [Diagram 3] FIG. 2 is a plan view illustrating a head unit constituting an ejection unit of the printing device, as viewed from the nozzle surface side. [Figure 4] FIG. [Diagram 5] FIG. 4 is a front view illustrating a sub-tank that constitutes the ejection unit. [Figure 6] FIG. 2 is a partial cross-sectional perspective view of the sub-tank; [Figure 7] FIG. 4 is an external perspective view illustrating a remaining amount detection unit of the subtank; [Figure 8] FIG. [Figure 9] 8 is an explanatory diagram illustrating the attachment positions (detection positions) of upper limit sensors and lower limit sensors in a plurality of discharge units, as viewed from the direction of arrow F in FIG. 7. FIG. [Figure 10] 11 is a flow diagram illustrating an example of control of a refill operation of a subtank with liquid; FIG. [Figure 11] 11 is an explanatory diagram showing an example of the relationship (drainage characteristics) between the discharge amount of the subtank and the displacement amount and pressure change of the displacement member. FIG. [Figure 12] 12A and 12B are explanatory diagrams illustrating the states of the displacement member of the sub tank at positions X0 and X1 in FIG. 11. [Figure 13] FIG. 10 is an explanatory diagram similar to FIG. 9 in accordance with a second embodiment of the present invention. [Figure 14] FIG. 2 is a front view of a discharge unit for explaining an example of a liquid supply system. [Figure 15] FIG. [Figure 16] 13 is a perspective view of a discharge unit for explaining another example of a body supply system. FIG. [Figure 17] FIG. [Figure 18] FIG. 4 is a schematic explanatory view of a first other example of a discharge unit. [Figure 19] FIG. 11 is a schematic explanatory view of a second alternative example of the discharge unit. [Figure 20] FIG. 11 is a schematic explanatory diagram of a printing apparatus as a liquid ejecting apparatus according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. A printing apparatus as a liquid ejecting apparatus according to a first embodiment of the present invention will be described with reference to Figures 1 and 2. Figure 1 is a schematic explanatory diagram of the printing apparatus, and Figure 2 is an explanatory diagram of the main parts of a printing unit 30 of the printing apparatus.

[0011] The printing device 1 includes an input section 10 for inputting a sheet material P, a pre-processing section 20, a printing section 30, a drying section 40, an unloading section 50, and an inversion mechanism section 60. The printing device 1 applies (coats) a pre-processing liquid to the sheet material P input (supplied) from the input section 10 in the pre-processing section 20, which is a pre-processing means, as necessary, applies a liquid to the sheet material P in the printing section 30 to perform the required printing, dries the liquid attached to the sheet material P in the drying section 40, and then discharges the sheet material P to the unloading section 50.

[0012] The loading section 10 includes an input tray 11 (lower input tray 11A, upper input tray 11B) that stores multiple sheet materials P, and a feeding device 12 (12A, 12B) that separates and sends out the sheet materials P one by one from the input tray 11, and supplies the sheet materials P to the pre-processing section 20.

[0013] The pre-treatment section 20 includes an application section 21 which is a treatment liquid application means for applying a treatment liquid to the printing surface of the sheet material P, the treatment liquid having the effect of, for example, agglomerating ink and preventing show-through.

[0014] The printing unit 30 includes a drum 31 which is a support member (rotating body) that supports the sheet material P on its peripheral surface and rotates, and a liquid ejection unit 32 which ejects liquid toward the sheet material P supported by the drum 31.

[0015] The printing section 30 also includes a transfer cylinder 34 that receives the sheet material P sent from the pre-processing section 20 and transfers the sheet material P between the drum 31, and a transfer cylinder 35 that receives the sheet material P transported by the drum 31 and transfers it to the inversion mechanism section 60.

[0016] The sheet material P transported from the pre-processing section 20 to the printing section 30 has its leading edge gripped by a gripping means (sheet gripper) provided on the transfer cylinder 34, and is transported as the transfer cylinder 34 rotates. The sheet material P transported by the transfer cylinder 34 is delivered to the drum 31 at a position opposite to the drum 31.

[0017] A gripping means (sheet gripper) is also provided on the surface of the drum 31, and the leading end of the sheet material P is gripped by the gripping means (sheet gripper). A plurality of suction holes are formed in a dispersed manner on the surface of the drum 31, and the suction means generates a suction airflow that flows inward from the required suction holes of the drum 31.

[0018] Then, the sheet material P transferred from the transfer cylinder 34 to the drum 31 has its leading edge gripped by the sheet gripper, and is adsorbed and supported on the drum 31 by the suction airflow of the suction means, and is transported as the drum 31 rotates.

[0019] The liquid discharge section 32 includes discharge units 33 (33A to 33E) which are liquid discharge means. For example, the discharge unit 33A discharges black (K), the discharge unit 33B discharges cyan (C) liquid, the discharge unit 33C discharges magenta (M), and the discharge unit 33D discharges yellow (Y) liquid. The discharge unit 33E is used as a discharge unit for discharging other special liquids such as white, gold (silver), etc.

[0020] As shown in FIG. 2, each ejection unit 33 (33A to 33E) of the liquid ejection section 32 includes a head unit (head module, head array) 200 that ejects liquid, and a sub-tank (liquid storage container) 300 (300A to 300E) that stores the liquid to be supplied to the head unit 200.

[0021] Here, each of the discharge units 33A to 33E is disposed in a normal direction to the center of the drum 31. In this embodiment, the discharge unit 33C is disposed in a perpendicular direction (vertical direction) passing through the center of the drum 31, and the discharge units 33A, 33B, 33D, and 33E are disposed at predetermined angles θ with respect to the discharge unit 33C.

[0022] The discharge operation of each discharge unit 33 of the liquid discharge section 32 is controlled by a drive signal corresponding to the printing information. When the sheet material P supported on the drum 31 passes through an area facing the liquid discharge section 32, liquid of each color is discharged from the discharge unit 33, and an image corresponding to the printing information is printed.

[0023] The reversal mechanism 60 is a mechanism that reverses the sheet material P by a switchback method when performing double-sided printing on the sheet material P handed over from the transfer cylinder 35, and the reversed sheet material P is sent back upstream of the transfer cylinder 34 through the conveying path 61 of the printing section 30.

[0024] The drying section 40 dries the liquid that has been applied to the sheet material P by the printing section 30. This causes the liquid content, such as water, in the liquid to evaporate, the colorant contained in the liquid to be fixed on the sheet material P, and curling of the sheet material P is suppressed.

[0025] The discharge section 50 includes a discharge tray 51 on which a plurality of sheet materials P are stacked. The sheet materials P conveyed from the drying section 40 are successively stacked and held on the discharge tray 51.

[0026] Next, an example of a head unit (head module, head array) constituting a discharge unit will be described with reference to Fig. 3. Fig. 3 is a plan view of the head unit as viewed from the nozzle surface side.

[0027] The head unit 200 has a plurality of heads 100 for ejecting liquid arranged in a staggered pattern on a base member 202 .

[0028] Each head 100 has a plurality of nozzle rows (four rows are shown here as an example, but the number is not limited thereto) in which a plurality of nozzles 104 for ejecting liquid are arranged.

[0029] In this embodiment, the heads 100 are arranged in a staggered pattern, so that the heads 100 in each row are arranged in a normal direction to the center of the drum 31, and are inclined so that the nozzle surfaces (ejection surfaces) 101 are in a tangential direction.

[0030] Next, an example of a discharge unit and a subtank will be described with reference to Figures 4 to 6. Figure 4 is an external perspective view of the discharge unit, Figure 5 is a front view of the subtank, and Figure 6 is a partial cross-sectional perspective view of the subtank.

[0031] The ejection unit 33 includes a head unit 200 and two sub-tanks 300 on a fixed member 350. The two sub-tanks 300 are arranged side by side in the head arrangement direction of the head unit 200.

[0032] The subtank 300 has a tank body 301 with one open side that constitutes a liquid storage portion 302 for storing liquid. The opening of the tank body 301 is sealed with a flexible membrane 303 such as a flexible film.

[0033] An elastic member (e.g., a spring) 304 is disposed within the liquid storage section 302 to bias the flexible membrane 303 in an out-of-plane direction. As the remaining amount of liquid within the liquid storage section 302 decreases, the biasing force of the elastic member 304 pushes the flexible membrane 303 in the out-of-plane direction, creating negative pressure.

[0034] A liquid supply port 305 is provided at the bottom of the tank body 301. By connecting a detachable connecting part to the liquid supply port 305, liquid is pumped from the main tank to the connecting part and replenishes the liquid storage part 302. A liquid delivery pump (liquid delivery part) is provided between the main tank and the subtank 300 to pump liquid from the main tank to the subtank 300. Liquid is delivered from the main tank to the liquid supply port 305 by the liquid delivery pump.

[0035] A liquid outlet 306 is provided at the top of the tank body 301. The liquid outlet 306 discharges the liquid to be supplied from the subtank 300 to the heads 100 by generating negative pressure. By connecting the liquid outlet 306 to a manifold that distributes and supplies the liquid to each head 100 by a tube or the like, the liquid discharged from the subtank 300 is distributed and supplied to each head 100.

[0036] An atmosphere vent mechanism 310, which is an atmosphere vent means for opening the inside of the subtank 300 to the atmosphere, is provided on the upper part of the tank body 301. By opening the atmosphere vent mechanism 310, the liquid storage section 302 is opened to the atmosphere (negative pressure is eliminated), and by opening the atmosphere vent mechanism 310, the liquid storage section 302 is sealed, making it possible to generate negative pressure.

[0037] The upper portion of the tank body 301 has two detection electrodes 311 (311a, 311b) for detecting when the remaining amount of liquid in the liquid storage portion 302 falls below a predetermined amount (end or near end: collectively referred to as the "end state"). Whether or not the liquid is in the end state can be determined by whether or not there is electrical continuity between the detection electrodes 311a, 311b through the liquid.

[0038] Next, the remaining amount detection means of the sub-tank will be described with reference to Figures 7 and 8. Figure 7 is an explanatory perspective view of the exterior of the sub-tank, and Figure 8 is an explanatory partial exploded perspective view of the sub-tank.

[0039] On the outer side of the flexible membrane 303 of the tank body 301, there is provided a displacement member 320 made of a filler, one end of which is supported by a shaft 321 so as to be able to swing.

[0040] The displacement member 320 is biased toward the tank body 301 by a pressing means such as a spring, and is pressed against the outer surface side of the flexible membrane 303. As a result, the displacement member 320 is displaced in conjunction with (follows) the movement of the flexible membrane 303, which is displaced according to the remaining amount of liquid in the liquid storage section 302.

[0041] On the other hand, sensor holding members (sensor brackets) 330, 330 attached to the fixed portion 301a of the tank body 301 each hold an upper limit sensor 331 as an upper limit detection means for detecting the displacement member 320, and a lower limit sensor 332 as a lower limit detection means for detecting the displacement member 320.

[0042] The upper limit sensor 331 detects the displacement member 320 when it is displaced to a position corresponding to a predetermined upper limit position (full position) of the remaining liquid amount. The lower limit sensor 332 detects the displacement member 320 when it is displaced to a position corresponding to a predetermined lower limit position (empty position) of the remaining liquid amount.

[0043] Sensor holding members 330, 330 which are detection means holding members for holding upper limit sensor 331 and lower limit sensor 332, respectively, are fixed to fixed portion 301a by fastening fastening member 335 to fixed portion 301a through elongated hole 336 provided in sensor holding member 330.

[0044] Here, the fixed position of the sensor holding member 330 holding the upper limit sensor 331 and the lower limit sensor 332 relative to the fixed part 301a can be adjusted by the long hole 336 in the displacement direction D of the displacement member 320. In other words, the detection position of the displacement member 320 by the upper limit sensor 331 and the lower limit sensor 332 can be adjusted.

[0045] This makes it possible to change (adjust) the upper limit detection position at which the upper limit sensor 331 detects the displacement member 320 and the lower limit detection position at which the lower limit sensor 332 detects the displacement member 320.

[0046] Next, the mounting positions (detection positions) of the upper limit sensors and the lower limit sensors in the plurality of discharge units 33 will be described with reference to Fig. 9. Fig. 9 is an explanatory view of Fig. 7, which is provided for the same description, viewed from the direction of arrow F.

[0047] In FIG. 9, the displacement member 320 of the subtank 300 is displaced in the direction of arrow D1 as the amount of liquid remaining in the liquid storage portion 302 decreases, and is displaced in the direction of arrow D2 as the amount of liquid remaining increases.

[0048] Here, as shown in FIG. 9(a), the upper limit sensor 331 and the lower limit sensor 332 of the sub-tank 300C of the ejection unit 33C arranged in the perpendicular direction detect the displacement member 320 at detection positions f1 and e1.

[0049] In contrast, the discharge unit 33B is disposed at an angle θ with respect to the discharge unit 33C. Therefore, the upper limit sensor 331 and the lower limit sensor 332 of the subtank 300B detect the displacement member 320 at detection positions f2 and e2 where the remaining amount of liquid is greater than the detection positions f1 and e1 of the subtank 300A of the discharge unit 33C, as shown in FIG. 9(b).

[0050] Furthermore, the discharge unit 33A is disposed at an angle θ with respect to the discharge unit 33B. Therefore, the upper limit sensor 331 and the lower limit sensor 332 of the subtank 300A detect the displacement member 320 at detection positions f3 and e3 where the remaining amount of liquid is greater than the detection positions f2 and e2 of the subtank 330B of the discharge unit 33B, as shown in FIG.

[0051] Next, an example of control of the refilling operation of the subtank 300 with liquid will be described with reference to the flow chart of FIG.

[0052] After opening the subtank 300 to the atmosphere, for example, liquid is pumped into the subtank 300 until liquid is detected between the detection electrodes 311a, 311b, and the subtank 300 is filled to capacity. Then, the liquid pump 561, which will be described later, is driven in reverse to return the liquid to the main tank 500, which will be described later (step S1, hereinafter simply referred to as "S1").

[0053] Then, it is determined whether the upper limit sensor 331 has detected the displacement member (referred to as "filler" in FIG. 10) 320 (S2), and after a predetermined amount of reverse transport has been performed since the upper limit sensor 331 detected the displacement member 320, the liquid delivery pump 561 is stopped (S3).

[0054] Next, it is determined whether the lower limit sensor 332 has detected the displacement member 320 (S4), and when the lower limit sensor 332 detects the displacement member 320, the liquid supply pump 561 is rotated forward (S5) to supply (replenish) liquid to the subtank 300.

[0055] Then, it is determined whether or not the liquid has been replenished until the upper limit sensor 331 detects the displacement member 320 (S6), and when the upper limit sensor 331 detects the displacement member 320, the liquid feed pump 561 is stopped and the process returns to step S4.

[0056] Moreover, when the lower limit sensor 332 does not detect the displacement member 320, it is determined whether the operation has ended, such as the device being stopped (S8), and the process returns to step 4 and is repeated until the operation has ended.

[0057] In this way, the liquid supply to the subtank 320 is controlled within a control range between the upper limit position where the upper limit sensor 331 detects the displacement member 320 and the lower limit position where the lower limit sensor 332 detects the displacement member 320. This control range is the appropriate negative pressure range for the subtank 320.

[0058] Next, the operation of this embodiment will be described with reference to Fig. 11 and Fig. 12. Fig. 11 is an explanatory diagram showing an example of the relationship (drainage characteristics) between the discharge amount of the subtank and the displacement amount and pressure change of the displacement member, and Fig. 12 is an explanatory diagram explaining the state of the displacement member of the subtank at positions X0 and X1 in Fig. 11.

[0059] Referring to FIG. 2 mentioned above, each of the discharge units 33A to 33E is disposed in a normal direction to the center of the drum 31, and the discharge units 33A, 33B, 33D, and 33E are disposed at a predetermined angle θ with respect to the discharge unit 33C.

[0060] The discharge unit 33 has the sub-tank 300 disposed above the nozzle surface 101 of the head 100 of the head unit 200. Therefore, the head difference between the nozzle surface 101 and the sub-tank 300 differs between the discharge units 33A to 33E depending on the inclination angle of the discharge units 33.

[0061] For example, if the head difference between the center of the subtank 300 and the nozzle surface 101 is L, then in the discharge unit 33C with an inclination angle of 0°, the head difference between the subtank 300 and the nozzle surface 101 is L. In contrast, in the discharge unit 33B (33D is the same) which is inclined at an angle θ with respect to the discharge unit 33C, the head difference between the subtank 300 and the nozzle surface 101 is L sin θ. Similarly, in the discharge unit 33A (33E is the same) which is inclined at an angle 2θ with respect to the discharge unit 33C, the head difference between the subtank 300 and the nozzle surface 101 is L sin 2θ.

[0062] In this manner, in this embodiment, the head difference between the nozzle surface 101 of the head 100 and the sub tank 300 differs between the multiple heads (ejection units 33).

[0063] Therefore, when the lower limit (closer to positive pressure) of the appropriate negative pressure for the head 100 of the ejection unit 33 is P, the negative pressure (called the "negative pressure inside the tank") P0 required for the sub-tank 300C of the ejection unit 33C arranged in the vertical direction is -(P+L) [kPa] obtained by adding the head difference L between the nozzle surface 101 of the head 100 and the sub-tank 300C to the appropriate negative pressure P.

[0064] The negative pressure P1 required within the tank for the sub-tank 300B of the ejection unit 33B, which is tilted at an angle θ with respect to the ejection unit 33C, is -(P+Lsinθ) [kPa] obtained by adding the head difference Lsinθ between the nozzle surface 101 of the head 100 and the sub-tank 300C to the appropriate negative pressure P.

[0065] Similarly, the negative pressure P2 required within the tank for the sub-tank 300A of the ejection unit 33A, which is tilted at an angle 2θ with respect to the ejection unit 33C, is -(P+Lsin2θ) [kPa] obtained by adding the head difference Lsin2θ between the nozzle surface 101 of the head 100 and the sub-tank 300C to the appropriate negative pressure P.

[0066] Next, referring to FIG. 11 , in the subtank 300, for example, the atmosphere is opened by an atmosphere opening mechanism 310, and the liquid is discharged from the liquid storage section 302 filled with liquid until the detection electrode 311 detects the liquid level, whereby the flexible membrane 303 is displaced inward against the biasing force of the elastic member 304.

[0067] As a result, the amount of displacement of the displacement member 320 increases as the amount of discharge increases, and the pressure inside the liquid storage portion 302 decreases (from positive pressure to negative pressure, and the negative pressure increases).

[0068] At this time, the position of the displacement member 320 of the subtank 300C for the internal negative pressure P0 (P0=P0+L) at which the appropriate negative pressure P of the head 100 is obtained is X0, and the state of the displacement member 320 of the subtank 300C becomes, for example, as shown in FIG. 12(a).

[0069] In contrast, the position of the displacement member 320 for the negative pressure P1 (P1=P0+Lsinθ) in the subtank 300B at which the appropriate negative pressure P for the head 100 is obtained is X1, and the state of the displacement member 320 of the subtank 300B becomes, for example, as shown in FIG. 12(b).

[0070] In other words, the discharge unit 33 with a large inclination angle can obtain an appropriate negative pressure P even if the amount of liquid discharged from the subtank 300 is small, compared to the discharge unit 33 with a small inclination angle.

[0071] Therefore, the upper limit sensor 331 of the subtank 300C of the discharge unit 33C is disposed at a position f1 to detect the displacement member 320 when the displacement member 320 is at position X0. Moreover, the upper limit sensor 331 of the subtank 300B of the discharge unit 33B is disposed at a position f2 to detect the displacement member 320 when the displacement member 320 is at position X1.

[0072] In this way, by varying the upper limit of the remaining liquid in the subtank 300 (referred to as the "content volume") depending on the degree of inclination (tilt angle) of the ejection unit 33, it is possible to reduce variations in the negative pressure in the head 100 caused by differences in the head head difference between the subtank 300 and the nozzle surface 101.

[0073] Furthermore, as in this embodiment, by varying the lower limit of the remaining amount of liquid in the sub-tank 300 depending on the degree of inclination of the ejection unit 33, the displacement range of the displacement member 320 between the sub-tanks 300 can be made uniform.

[0074] Next, a second embodiment of the present invention will be described with reference to Fig. 13. Fig. 13 is an explanatory view similar to Fig. 9, which is provided for explaining the mounting positions (detection positions) of upper limit sensors and lower limit sensors of a plurality of discharge units in the second embodiment.

[0075] In this embodiment, the lower limit position at which the lower limit sensor 332 detects the displacement member 320 is the same. At this time, the position of the maximum value of the negative pressure in the tank (the lower limit of the negative pressure) is the same at a predetermined value (for example, a position around -2 kPa) regardless of the inclination of the discharge unit 33.

[0076] In this case, the sub-tank 300B of a head with a relatively large tilt angle (eg, ejection unit 33B) has a greater distance between its upper limit and lower limit positions than the sub-tank 300A of a head with a relatively small tilt angle (eg, ejection unit 33A).

[0077] As a result, when the inclination of the discharge unit 33 is small, a large negative pressure is required, so the control range (the range from the lower limit to the upper limit of the remaining liquid amount) becomes narrower, and the cycle of replenishment from the main tank 500 is shortened to ensure a large negative pressure in the tank.

[0078] In contrast, when the discharge unit 33 has a large inclination, the refilling operation can be performed even with a small negative pressure in the tank. Therefore, by lengthening the period of refilling from the main tank 500, the downtime due to refilling can be reduced.

[0079] Next, an example of a liquid supply system will be described with reference to Figures 14 and 15. Figure 14 is a front explanatory view of a discharge unit provided for the description, and Figure 15 is a side explanatory view of the same including a main tank.

[0080] The discharge unit 33 can be used by mounting a plurality of heads 100 on a base member 202. A manifold 150 is disposed on the upper portion of the discharge unit 33, and liquid can be distributed from a common flow path 151 of the manifold 150 through branch paths 152 to each head 100 mounted at each mounting position 203 to each head 100.

[0081] A main bracket 401 and a sub bracket 402 for mounting the sub tank 300 are attached to the front plate of the discharge unit 33, and the sub tank 300 is mounted by using these.

[0082] The liquid stored in the main tank 500 is sent to each part through piping. The liquid is sent from the main tank 500 to a filter 561 through a supply pipe (tube, etc.) 571, and the liquid that has passed through the filter 561 is sent to a supply port 305 located at the bottom of the sub-tank 300 through a liquid supply pipe 572, where it is replenished in the liquid storage part 302.

[0083] The liquid in the sub-tank 300 is sent from a liquid outlet 306 located at the top of the sub-tank 300 through a pipe 573 to a common flow path 151 of the manifold 150 , and is supplied to each head 100 from a branch path 152 .

[0084] Next, another example of the liquid supply system will be described with reference to Figures 16 and 17. Figure 16 is a perspective explanatory view of a discharge unit provided for the description, and Figure 17 is a plan explanatory view of the main part of the same.

[0085] Here, sub-brackets 402a and 402b are provided, and sub-tanks 300 are attached to them, respectively, so that liquid is supplied from the two sub-tanks 300 to the head unit 200.

[0086] Next, another example of the discharge unit will be described with reference to Figures 18 and 19. Figures 18 and 19 are schematic explanatory views of the discharge unit.

[0087] The first example of the ejection unit 33 shown in Figure 18 can be mounted on the base member 202 so that the orientation of the nozzle surface 101 differs between two rows (even) on one side and two rows (odd) on the other side, separated by the structure 204.

[0088] The base member 202 is disposed with a tilt at different angles on the left and right sides so that the nozzle faces 101 of the heads 100 face the outer circumferential surface of the drum 31, with the structure 204 as the boundary. Each head 100 mounted on the discharge unit 33 faces in a direction in which the nozzle faces 101 face the outer circumferential surface of the drum 31 at the left and right positions, with the structure 204 as the boundary.

[0089] In this first example, four sub-tanks 300 are arranged for each row of the heads 100. This makes it possible to allocate and use, for example, four types of liquid (CMYK, etc.) for each head row.

[0090] 19, two sub-tanks 300 are arranged on one side for each of the two rows of heads 100. This allows, for example, two types of liquid (such as two colors) to be assigned to each of the two rows for use.

[0091] Next, a printing apparatus as a liquid ejecting apparatus according to a third embodiment of the present invention will be described with reference to Fig. 20. Fig. 20 is a schematic explanatory diagram of the printing apparatus.

[0092] In this printing device 1, a web 1000 such as continuous paper fed from a feed roll 1010 is guided to a printing section 1030 via multiple guide rollers 1007. In the printing section 1030, the web 1000 is guided by multiple guide rollers 1031 facing each of the discharge units 33, and printing is performed by ejecting a required liquid from each of the discharge units 33.

[0093] Then, the web 1000 printed in the printing section 1030 is guided by a plurality of guide rollers 1007 while the printed surface is dried by a drying device 1040 , and then the web 1000 is wound up on a take-up roll 1050 .

[0094] In the above embodiment, an example is described in which the sub-tank is disposed above the head, and the sub-tank and the head are disposed at an angle, but the present invention is not limited to this configuration. For example, the present invention can be applied to a configuration in which multiple heads are disposed without an angle, and the sub-tank is disposed above the head, but the height of the sub-tank differs between the heads. Also, the present invention can be applied to a configuration in which the sub-tank is disposed below the head, but the height of the sub-tank differs between the heads.

[0095] In the present application, the liquid to be ejected may have a viscosity and surface tension that allows it to be ejected from the head, and is not particularly limited, but it is preferable that the viscosity of the liquid is 30 mPa·s or less at room temperature and pressure, or by heating or cooling. More specifically, the liquid may be a solution, suspension, emulsion, etc., containing a solvent such as water or an organic solvent, a colorant such as a dye or pigment, a functionalizing material such as a polymerizable compound, a resin, or a surfactant, a biocompatible material such as DNA, amino acids, proteins, or calcium, an edible material such as a natural colorant, etc., and these can be used for applications such as inkjet ink, surface treatment liquid, a liquid for forming a component of an electronic element or a light-emitting element, an electronic circuit resist pattern, a material liquid for three-dimensional modeling, etc.

[0096] Energy sources for ejecting liquid include 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.

[0097] Furthermore, the term "device for ejecting liquid" includes not only devices capable of ejecting liquid onto objects to which the liquid can adhere, but also devices that eject liquid into air or liquid.

[0098] This "liquid ejecting device" can also include means for feeding, transporting, and discharging items onto which liquid can be attached, as well as pre-processing devices and post-processing devices.

[0099] For example, examples of "devices that eject liquid" include image forming devices that eject ink to form an image on paper, and three-dimensional modeling devices that eject modeling liquid onto a powder layer formed by layering powder in order to create a three-dimensional object (a three-dimensional model).

[0100] In addition, the term "liquid ejection device" is not limited to devices that use ejected liquid to visualize meaningful images such as letters and figures. For example, it also includes devices that form patterns that have no meaning in themselves and devices that create three-dimensional images.

[0101] 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 to which the liquid adheres and penetrates, etc. Specific examples include media such as paper, recording paper, film, cloth, and other recording media, electronic boards, electronic components such as piezoelectric elements, powder layers, organ models, and test cells, and unless otherwise specified, includes all objects to which liquid can adhere.

[0102] The material of the above-mentioned "object to which liquid can adhere" may be any material to which liquid can adhere even temporarily, such as paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, and ceramics.

[0103] Furthermore, the "liquid ejection device" may be a device in which a liquid ejection head and an object to which liquid can be attached move relatively, but is not limited to this. Specific examples include a serial type device in which a liquid ejection head moves, a line type device in which a liquid ejection head does not move, etc.

[0104] Other examples of "liquid ejecting devices" include a treatment liquid application device that ejects a treatment liquid onto 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.

[0105] In the present application, the terms image formation, recording, printing, imprinting, printing, modeling, and the like are all synonymous. [Explanation of symbols]

[0106] 1 Printing device 10 Loading section 20 Pretreatment section 30 Printing Department 31 Drums 40 Drying section 50 Unloading section 60 Reversing mechanism 33 Discharge unit 100 Liquid ejection head (head) 200 Head Unit 300 Subtank 331 Upper limit sensor (upper limit detection means, detection means) 332 Lower limit sensor (lower limit detection means, detection means)

Claims

1. A plurality of heads for ejecting liquid; a plurality of sub-tanks each containing liquid to be supplied to each of the plurality of heads; the plurality of heads and the plurality of sub-tanks are disposed at an angle with respect to a vertical direction, the sub-tank has an upper limit detection means for detecting an upper limit position of the remaining amount of liquid, and a lower limit detection means for detecting a lower limit position of the remaining amount of liquid, The sub-tank of the head having a relatively large inclination angle has a larger distance between the upper limit position and the lower limit position than the sub-tank of the head having a relatively small inclination angle. A liquid ejection device comprising:

2. the upper limit detection means and the lower limit detection means are attached to a detection means holding member, The mounting position of the detection means is different due to the difference in the mounting position of the detection means holding member.

2. The liquid dispensing device according to claim 1.

3. The control range of the pressure in the sub-tank varies depending on the tilt angle of the head.

3. The liquid ejection device according to claim 1 or 2.

4. A plurality of heads for ejecting liquid; a plurality of sub-tanks each containing liquid to be supplied to each of the plurality of heads; the plurality of heads and the plurality of sub-tanks are disposed at an angle with respect to a vertical direction, The sub-tank has a detection means for detecting an upper limit position of a remaining amount of liquid, The attachment position of the detection means of the sub-tank varies depending on the inclination angle of the head, The control range of the pressure in the sub-tank varies depending on the tilt angle of the head. A liquid ejection device comprising:

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