Liquid discharging device, vacuum waste liquid tank, and nozzle suction method

Abstract

To provide a liquid discharging device which is capable of executing nozzle suction even when a suction pump cannot be driven, and which can prevent contamination due to leakage of residual liquid.SOLUTION: A liquid discharging device comprises: a liquid discharge head 34; a head tank 35; a cap 82a for capping a nozzle surface 23; a suction pump 20 forming negative pressure inside the cap 82a; a tube member 19 of which one end is connected to the cap 82a, and which has a hollow needle-like member 120 at the other end, in order to guide waste liquid exhausted into the cap 82a; and a waste liquid tank mounting part 140. The waste liquid tank mounting part 140 is capable of mounting a vacuum waste liquid tank 100 which comprises a seal member 118 through which the needle-like member 120 can be pierced. During non-driving time of the suction pump 20, the needle-like member 120 is pierced through the seal member 118 of the vacuum waste liquid tank 100 so that negative pressure is formed in the cap 82a, whereby waste liquid is suctioned into the vacuum waste liquid tank 100.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to a liquid ejection device, a vacuum waste liquid tank, and a nozzle suction method. [Background technology]

[0002] As an example of a device that ejects liquid, there is known an image forming device (inkjet printer) that ejects droplets of ink from a liquid ejection head and causes the ink to land on a medium to form an image pattern (also called recording, printing, copying, printing, etc.).

[0003] In an image forming apparatus, since a liquid ejection head ejects ink from a nozzle, there is a problem that ejection failure occurs due to an increase in ink viscosity caused by evaporation of a solvent from the nozzle, solidification of the ink, adhesion of dust, and further mixing of air bubbles, which causes an ejection failure and leads to recording failure. To address this problem, a configuration equipped with a maintenance and recovery mechanism that maintains and recovers the performance of the liquid ejection head is known.

[0004] The maintenance and recovery mechanism includes a cap that seals the nozzle surface of the liquid ejection head, and by capping, the ink in the nozzles is prevented from drying out or becoming thicker. Also, before, during, or after a recording operation, the nozzle surface is capped and a suction pump is driven to forcibly discharge the liquid from the nozzles (nozzle suction), which ejects droplets that do not contribute to image formation, and wiping the nozzle surface with a wiper member.

[0005] Waste liquid discharged during an operation for maintaining and recovering the performance of the liquid ejection head is discharged into a cap or a dedicated empty ejection receiver, and is then stored in a waste liquid tank (see, for example, Patent Document 1). Patent Document 1 discloses an apparatus that includes a waste liquid tank that contains an absorbing member that absorbs waste liquid and is configured so that air within the waste liquid tank can be directly discharged to the outside of the waste liquid tank. Summary of the Invention [Problem to be solved by the invention]

[0006] If the ejection failure cannot be resolved even after the operation of the maintenance and recovery mechanism, or if other problems occur, the device will need to be repaired or replaced, in which case the device will need to be transported.

[0007] The nozzle suction operation is performed by driving a suction pump to generate negative pressure to suck up waste liquid. Therefore, if the suction pump cannot be driven due to an abnormality in the device or if the power supply cannot be used, the nozzle suction operation cannot be performed and ink remains in the liquid ejection head and head tank.

[0008] If the device is transported in this state, the ink remaining in the liquid ejection head and head tank may leak out due to vibrations during transport or tilting of the device, and the leaked ink may soil not only the inside of the device but also the surrounding area.

[0009] Therefore, an object of the present invention is to provide a liquid ejection device that can perform nozzle suction even when the suction pump cannot be driven, and that can prevent damage caused by leakage of liquid remaining in the liquid ejection head or head tank. [Means for solving the problem]

[0010] In order to solve the above problems, the liquid ejecting device of the present invention comprises a liquid ejection head having a nozzle for ejecting liquid, a cap for capping the nozzle surface of the liquid ejection head, a suction pump for creating negative pressure within the cap, a tube member having one end connected to the cap and a hollow needle-shaped member at the other end for guiding waste liquid discharged into the cap, a waste liquid tank that is detachably connected to the tube member and stores the waste liquid, and a waste liquid tank mounting portion for replaceably mounting the waste liquid tank, wherein the waste liquid tank mounting portion is capable of mounting a vacuum waste liquid tank that seals the tank so as to maintain a negative pressure state inside and has a sealing member that can be pierced by the needle-shaped member, and when the suction pump is not driven, a negative pressure is created within the cap by piercing the sealing member of the mounted vacuum waste liquid tank, and the waste liquid is sucked into the vacuum waste liquid tank. Effect of the Invention

[0011] According to the present invention, it is possible to provide a liquid ejection device that can perform nozzle suction even when the suction pump cannot be driven, and that can prevent contamination due to leakage of liquid remaining in the liquid ejection head or head tank. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram illustrating a mechanism of an image forming apparatus that is an embodiment of a device for discharging liquid according to the present invention; [Diagram 2] FIG. 2 is a plan view illustrating a main portion of the image forming apparatus. [Diagram 3] FIG. 2 is a block diagram illustrating the overall configuration of the liquid flow. [Figure 4] FIG. 2 is a schematic side view illustrating a maintenance and recovery mechanism. [Diagram 5] FIG. 4 is a plan view illustrating a main part of a maintenance and recovery mechanism. [Figure 6] 4A and 4B are an explanatory perspective view and a side view of a maintenance recovery mechanism and a replacement waste liquid tank. [Figure 7]FIG. 4 is a schematic explanatory diagram illustrating a main connection part from the head tank to the replacement waste liquid tank. [Figure 8] FIG. 2 is a schematic diagram showing an example of a vacuum waste liquid tank. [Figure 9] FIG. 2 is a schematic explanatory diagram of an embodiment of suction by a vacuum waste liquid tank. [Figure 10] FIG. 2 is a schematic explanatory diagram showing an example of a fixed waste liquid tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The liquid ejecting device, the vacuum waste liquid tank, and the nozzle suction method according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and may be modified within the scope of what a person skilled in the art can imagine, such as other embodiments, additions, modifications, deletions, etc., and any aspect is included in the scope of the present invention as long as it provides the functions and effects of the present invention.

[0014] An image forming apparatus as one embodiment of a liquid ejecting apparatus to which the present invention is applied will be described with reference to FIGS. 1 to 3. FIG. As an example of an image forming apparatus, an image is formed (also called recording, printing, imprinting, printing, etc.) by applying a recording liquid (ink) to a medium such as paper (hereinafter also called "paper"), but the liquid is not limited to recording liquid or ink, and is not particularly limited as long as it is a liquid that can form an image. In addition, examples of the medium include paper, thread, fiber, cloth, leather, metal, plastic, glass, wood, ceramics, etc. "Image formation" refers not only to imparting meaningful images such as characters and figures to a medium, but also to imparting meaningless images such as patterns to a medium.

[0015] Fig. 1 is a side view illustrating the overall configuration of an image forming apparatus (serial type inkjet printer) as an example of an apparatus that ejects liquid, Fig. 2 is a plan view illustrating the main parts of the same apparatus, and Fig. 3 is a block diagram illustrating the overall configuration of the flow of liquid (ink).

[0016] In the image forming apparatus, a carriage 33 is held slidably in a primary scanning direction D1 by primary and secondary guide rods 31 and 32, which are guide members horizontally mounted on left and right side plates 21A and 21B of the apparatus main body 1. The carriage 33 is reciprocated in the primary scanning direction D1 via a timing belt by a primary scanning motor (not shown).

[0017] The carriage 33 is equipped with a liquid ejection head 34 and a head tank 35. The liquid ejection head 34 of the liquid ejection unit ejects liquid of each color, for example, yellow (Ye), cyan (Cy), magenta (Ma), and black (Bk). The liquid ejection head 34 is mounted with a nozzle row made up of a plurality of nozzles arranged in a sub-scanning direction D2 perpendicular to the main scanning direction D1, and the ejection direction facing downward.

[0018] Each liquid ejection head 34 has two nozzle rows, one of which of liquid ejection head 34a ejects black (Bk) droplets and the other of which of liquid ejection head 34b ejects magenta (Ma) droplets and the other of which of liquid ejection head 34b ejects yellow (Ye) droplets.

[0019] A head tank 35 for supplying ink of each color corresponding to the nozzle rows of the liquid ejection head 34 is replenished with ink of each color from ink cartridges 10y, 10m, 10c, and 10k of each color that are detachably mounted in the cartridge loading section 4 by a supply pump unit 5 through supply tubes 36 of each color. The operation of the supply pump unit 5 is controlled by a control section 6.

[0020] On the other hand, as a paper feeding section for feeding the paper 42 loaded on the paper loading section (pressure plate) 41 of the paper feed tray 2, there is provided a crescent roller (paper feed roller) 43 that separates and feeds the paper 42 one sheet at a time from the paper loading section 41, and a separation pad 44 facing the paper feed roller 43 and made of a material with a large friction coefficient, and this separation pad 44 is biased toward the paper feed roller 43.

[0021] In order to send the paper 42 fed from the paper feed section to the lower side of the liquid ejection head 34, the printer is provided with a guide member 45 for guiding the paper 42, a counter roller 46, a transport guide member 47, and a pressing member 48 having a tip pressure roller 49, as well as a transport belt 51 which is a transport means for electrostatically adsorbing the fed paper 42 and transporting it to a position opposite the liquid ejection head 34.

[0022] The conveyor belt 51 is an endless belt that is stretched between a conveyor roller 52 and a tension roller 53 and rotates in the belt conveying direction (sub-scanning direction D2). The conveyor belt 51 is also provided with a charging roller 56 that is a charging means for charging the surface of the conveyor belt 51. The charging roller 56 comes into contact with the surface of the conveyor belt 51 and rotates following the rotation of the conveyor belt 51. The conveyor belt 51 moves in the belt conveying direction in FIG. 2 as the conveyor roller 52 is rotationally driven via a timing provided by a sub-scanning motor (not shown).

[0023] The paper discharge section for discharging the paper 42 recorded by the liquid ejection head 34 includes a separation claw 61 for separating the paper 42 from the conveyor belt 51, a paper discharge roller 62, and a spur 63 which is a paper discharge roller, and a paper discharge tray 3 is provided below the paper discharge roller 62.

[0024] In addition, a duplex unit 71 is detachably attached to the rear portion of the device main body 1. The duplex unit 71 takes in the paper 42 returned by the reverse rotation of the conveyor belt 51, inverts it, and feeds it again between the counter roller 46 and the conveyor belt 51. In addition, the upper surface of the duplex unit 71 serves as a manual feed tray 72.

[0025] As shown in FIG. 2, a maintenance and recovery mechanism 81 for maintaining and recovering the state of the nozzles of the liquid ejection head 34 is disposed in a non-printing area on one side of the carriage 33 in the scanning direction. The maintenance and recovery mechanism 81 includes caps 82a, 82b (referred to as "cap 82" when no distinction is made) for capping the nozzle surface of the liquid ejection head 34, a wiper member 83 for wiping the nozzle surface, an idle ejection receiver 84 for receiving droplets when idle ejection is performed in which droplets that do not contribute to recording are ejected in order to expel thickened recording liquid, and a carriage lock 87 for locking the carriage 33.

[0026] A waste liquid tank mounting section 140 is provided on the side of the maintenance and recovery mechanism 81 below the cartridge loading section 4, for mounting a waste liquid tank (replacement waste liquid tank 101, or vacuum waste liquid tank 100 described later) replaceably from the front side of the device body. The ink cartridge 10 and the replacement waste liquid tank 101 can be replaced from the front side of the device body by opening a common cover on the front side of the device body. In addition, a fixed waste liquid tank 200 for storing waste liquid generated from the empty discharge receiver 84 is provided below the maintenance and recovery mechanism 81.

[0027] Also, as shown in FIG. 2, in the non-printing area on the other side of the scanning direction of the carriage 33, an empty discharge receiver 88 is arranged to receive droplets when empty discharge is performed in which droplets that do not contribute to recording are discharged in order to expel ink that has thickened during recording, etc., and this empty discharge receiver 88 is provided with an opening 89 aligned in the nozzle row direction of the liquid discharge head 34.

[0028] In the image forming apparatus configured in this manner, the sheets of paper 42 are separated and fed one by one from the paper feed tray 2. The sheets of paper 42 fed approximately vertically upward are guided by the guide 45, sandwiched between the conveyor belt 51 and the counter roller 46, and conveyed. The leading edge of the sheets of paper 42 is further guided by the conveyor guide 37 and pressed against the conveyor belt 51 by the leading edge pressure roller 49, thereby changing the conveying direction by approximately 90°.

[0029] At this time, an alternating voltage is applied to the charging roller 56 so that positive and negative outputs are alternately repeated, and the conveyor belt 51 is charged with an alternating charging voltage pattern, that is, the conveyor belt 51 is charged with alternating positive and negative charges in a band shape of a predetermined width in the sub-scanning direction which is the rotation direction. When the paper 42 is fed onto the conveyor belt 51 which is alternately charged with positive and negative charges, the paper 42 is attracted to the conveyor belt 51, and the paper 42 is conveyed in the sub-scanning direction by the rotation of the conveyor belt 51.

[0030] Therefore, by driving the liquid ejection head 34 in response to an image signal while moving the carriage 33, ink droplets are ejected onto the stationary paper 42 to record one line, and after transporting the paper 42 a predetermined distance, the next line is recorded. Upon receiving a recording end signal or a signal indicating that the rear end of the paper 42 has reached the recording area, the recording operation is terminated and the paper 42 is discharged to the paper discharge tray 3.

[0031] When performing nozzle maintenance and recovery of the liquid ejection head 34, the carriage 33 is moved to a position facing the maintenance and recovery mechanism 81, which is the home position, and maintenance and recovery operations such as nozzle suction, which performs capping with a cap 82 and sucking from the nozzles, and blank ejection, which ejects droplets that do not contribute to image formation, are performed. This allows stable image formation.

[0032] An example of the maintenance and recovery mechanism 81 is shown in Figures 4 and 5. Figure 4 is a schematic diagram of the maintenance and recovery mechanism, and Figure 5 is a plan view of the main part.

[0033] This maintenance recovery mechanism 81 has caps 82a, 82b held by a cap holder 212, a wiper member 83 including an elastic body, and a wiper cleaner 86, which is a first wiper cleaning means, held on a maintenance device frame 211 so that they can each be raised and lowered (moved up and down).

[0034] The cap 82 is a box-shaped member having an opening on the side facing the nozzle surface of the liquid ejection head 34. The cap 82 has, for example, an elastic portion on the upper surface of the opening, and the nozzle opening can be sealed (capped) by bringing this elastic portion into close contact with the nozzle surface. An absorbing member (for example, a porous sponge-like member, etc.) may be disposed inside the cap 82.

[0035] A cylindrical vacant discharge receiver 84 is disposed between the wiper member 83 and the cap 82a, and a wiper cleaner portion 85 is formed at the upper end of the vacant discharge receiver 84 on the wiper member 83 side as a second wiper cleaning means for scraping off and removing ink adhering to the wiper member 83. When cleaning the wiper member 83, the wiper member 83 is pressed against the wiper cleaner portion 85 by a wiper cleaner 86, and the wiper member 83 is lowered in this state, whereby the ink adhering to the wiper member 83 is scraped off toward the vacant discharge receiver 84 side.

[0036] A suction pump 20, which is a suction means, is connected to the cap 82a closest to the print area R via a flexible tube member 19 made of an elastic material, and a negative pressure is generated within the cap 82a. The cap 82a is a cap for keeping moisture and for suction, and the cap 82b is a cap for keeping moisture. When performing nozzle suction, the liquid ejection head 34 is moved to a position where it can be capped with the cap 82a.

[0037] An example of the suction pump 20 is one that generates a suction force by repeatedly applying pressure and moving a plurality of pressure members to the tube member 19. The operation of the suction pump 20 is controlled by the control unit 6 (see FIG. 3).

[0038] Since the tube member 19 temporarily stores ink inside, it is preferable to form it from a material that is unlikely to allow water vapor to permeate from the tube wall surface, and for example, a tube made of a silicone tube or a thermoplastic elastomer can be used. The water vapor permeability of the thermoplastic elastomer is preferably 15 g / m2·day or less. In addition, by using a thermoplastic elastomer with a hardness of approximately 50 degrees according to the JIS-A standard for the tube member 19, elasticity that enables liquid to be pumped can be obtained, and the pump driving load can be reduced.

[0039] A cam shaft 221 rotatably supported by the frame 211 is disposed below the caps 82a, 82b, wiper member 83, etc., and the cam shaft 221 is provided with a cap cam 222 for raising and lowering the cap holder 212, a wiper cam 224 for raising and lowering the wiper member 83, a roller 226 as a rotating body on which droplets discharged idly in the idling receiver 84 catch, a cleaner cam 228 for oscillating the wiper cleaner 86, and a carriage lock cam 229 for raising and lowering the carriage lock 87.

[0040] In order to rotate the suction pump 20 and the camshaft 221, a motor gear 232 provided on a motor shaft 231a of a maintenance and recovery motor 231 is engaged with a pump gear 233 provided on a pump shaft 20a of the suction pump 20, and further an intermediate gear 234 integral with the pump gear 233 is engaged with an intermediate gear 236 equipped with a one-way clutch 237 via an intermediate gear 235, and a cam gear 240 fixed to the camshaft 221 is engaged with an intermediate gear 238 coaxial with the intermediate gear 236 via an intermediate gear 239. An intermediate shaft 241, which is the rotation shaft of the intermediate gears 236 and 238 equipped with the clutch 237, is rotatably held by the frame 211.

[0041] In this maintenance and recovery mechanism 81, when removing ink or impurities adhering to the nozzle surface 23 of the liquid ejection head 34, the motor 231 is driven to raise the wiper member 83 via the wiper cam 224. In this state, the carriage 33 is moved in the main scanning direction, whereby the wiper member 83 wipes the nozzle surface of the liquid ejection head 34 to remove impurities and the like.

[0042] When covering the nozzle surface of the liquid ejection head with the cap , for example, the motor 231 is rotated to raise the cap via the cap cam 213, thereby capping the nozzle surface of the liquid ejection head . Before, during, or after the printing operation, nozzle suction is performed via the cap 82a, or ink droplets that do not contribute to the printing operation (idle ejection) are ejected to maintain the nozzle ejection performance. The ink (waste liquid) discharged into the cap 82a is guided by the tube member 19 in the direction of the arrow F, and sent to a replacement waste liquid tank 101 (or a vacuum waste liquid tank 100, which will be described later).

[0043] Fig. 6(A) is a perspective explanatory diagram showing an example of a maintenance recovery mechanism and a replacement waste liquid tank, and Fig. 6(B) is a side explanatory diagram. Fig. 7 is a schematic explanatory diagram explaining the main connection parts of the head tank and the liquid ejection head to the replacement waste liquid tank. Note that Fig. 7 shows a replacement waste liquid tank of a different embodiment from that shown in Fig. 6.

[0044] As shown in FIG. 6, this image forming apparatus is equipped with a removable replacement waste liquid tank 101 that stores and holds waste liquid discharged from the cap 82a in the waste liquid tank mounting section 140, and a fixed waste liquid tank 200 that stores and holds waste liquid (waste ink) from the empty discharge receiver 84 of the maintenance and recovery mechanism 81.

[0045] 6 and 7, the replacement waste liquid tank 101 mounted on the waste liquid tank mounting part 140 is, for example, a container with a sealed structure formed by a container body 101a and a lid member 101b. An absorbent member with a multi-layer structure (for example, a three-layer structure) made of a fibrous nonwoven fabric or a sponge-like absorbent that absorbs and holds the waste liquid may be provided inside. The container body 101a and the lid member 101b are sealed by welding or by using an elastic member 119 such as a packing.

[0046] One end of the exchange waste liquid tank 101 in the longitudinal direction is provided with a waste liquid inlet port 117 that is detachably connected in a sealed state via a hollow needle-shaped member 120 that is a connecting member of the tube member 19. Also, an atmosphere communication port 116 that communicates between the inside and outside of the tank is provided on the top surface on the other end side in the longitudinal direction. If the opening of the atmosphere communication port 116 is large, the waste liquid will easily overflow from the exchange waste liquid tank 101 and the waste liquid contained in the exchange waste liquid tank 101 will be accelerated to dry out, so it is preferable that the opening be small.

[0047] As shown in FIG. 7, the pressure in the head tank 35 for each color is maintained at V1, which is lower than the surrounding atmospheric pressure V0, thereby preventing ink that is not involved in image formation from dripping. When performing nozzle suction, the suction pump 20 is driven with the cap 82a pressed against the nozzle surface 23 of the target liquid ejection head 34, and the pressure V2 inside the cap 82a is set to a pressure lower than the pressure V1 of the head tank 35. This causes the ink in the liquid ejection head 34 and the head tank 35 to be sucked and discharged into the cap 82a. Accordingly, air bubbles and ink clogging in the nozzles 22 are also removed. The ink discharged into the cap 82a is sent as waste liquid via the tube member 19 and stored in the replacement waste liquid tank 101.

[0048] For safety reasons, if a malfunction such as a breakdown occurs in the image forming apparatus, the apparatus will not operate even if the power is turned on. In this case, the suction pump 20 cannot be driven, which causes a problem that the ink remaining in the liquid ejection head 34 and the head tank 35 cannot be sucked and removed. In contrast, the liquid ejecting device of the present invention is equipped with a vacuum waste liquid tank, making it possible to suck and remove ink remaining in the liquid ejection head 34 and head tank 35 even when power is not applied or when the suction pump 20 cannot be driven.

[0049] With this configuration, for example, when a broken device needs to be collected and moved for repair, it is possible to prevent ink remaining in the liquid ejection head 34 or head tank 35 from leaking out and soiling the inside of the device due to vibration during transportation, tilting of the device, pressure fluctuations in the transport environment, etc. Furthermore, preventing ink leakage improves the ease of repair work.

[0050] Nozzle suction using a vacuum waste liquid tank will be described with reference to FIGS. Fig. 8 is a schematic diagram showing an example of a vacuum waste liquid tank, and Fig. 9 is a schematic explanatory diagram of the manner of suction by the vacuum waste liquid tank. Note that "vacuum" refers to a state in which a space is filled with gas at a pressure lower than normal atmospheric pressure.

[0051] The vacuum waste liquid tank 100 of the present invention is a waste liquid tank to be attached to a device for discharging liquid, the waste liquid tank comprising: a liquid discharge head 34 having a nozzle for discharging liquid, a head tank 35 for supplying liquid to the liquid discharge head 34, a cap 82a for capping the nozzle surface 23 of the liquid discharge head 34, and a tube member 19 having one end connected to the cap 82a and a hollow needle-shaped member 120 at the other end for guiding waste liquid discharged into the cap 82a, and is provided with a sealing member 118 that seals the tank so as to maintain a negative pressure state inside and can be pierced by the needle-shaped member 120, and when the needle-shaped member 120 of the tube member 19 is pierced through the sealing member 118, a negative pressure is created within the cap 82a and the waste liquid is sucked in.

[0052] When the negative pressure in the vacuum waste liquid tank is such that the atmospheric pressure is V0, the pressure in the head tank 35 is V1, the pressure in the cap 82a is V2, and the pressure in the sealed vacuum waste liquid tank 100 is V3, the relationship V3 < V2 < V1 < V0 is satisfied. As a result, when the needle member 120 of the tube member 19 penetrates the seal member 118 and the inside of the vacuum waste liquid tank 100 communicates with the cap 82a via the tube member 19, the pressure inside the cap 82a is reduced more than that inside the head tank 35 due to the negative pressure in the vacuum waste liquid tank.

[0053] That is, by using the vacuum waste liquid tank 100 with the pressure V3 satisfying the above relationship, even when the power is off or the suction pump 20 is not driven, the pressure inside the cap 82a can be made more negative than the pressure in the head tank 35 by the negative pressure in the vacuum waste liquid tank 100, enabling nozzle suction.

[0054] Also, when performing nozzle suction by the negative pressure in the vacuum waste liquid tank 100, since a sharp pressure reduction occurs simultaneously when the needle member 120 penetrates the vacuum waste liquid tank 100, the effect of nozzle suction is improved compared to the gentle pressure reduction by the suction pump 20 with controlled operation. For example, even when there is thickened ink or clogging at the nozzle in the image forming apparatus, the ink can be easily discharged from the head tank 35.

[0055] As shown in FIG. 8, the vacuum waste liquid tank 100 is a container with a sealed structure formed by a container body 100a, a lid member 100b, and a seal member 118. The lid member 100b is provided with an opening 100c through which the needle member 120 can penetrate. As the material of the seal member 118, an elastic body with excellent airtightness and capable of being penetrated by the needle member 120 is preferable, and examples include butyl rubber.

[0056] The container body 100a is preferably made of a material with excellent gas barrier properties in order to maintain the degree of vacuum inside the container. The gas barrier properties can be improved by performing aluminum deposition on the container surface. Similarly, a decrease in the degree of vacuum can be prevented by a method of attaching a film with gas barrier properties, a method of coating the surface with a resin material with high gas barrier properties, or the like. An example of a material with excellent gas barrier properties is polyvinylidene chloride (PVDC).

[0057] The liquid ejection device according to the present invention includes a liquid ejection head 34 having a nozzle for ejecting liquid, a head tank 35 for supplying liquid to the liquid ejection head 34, a cap 82a for capping the nozzle surface 23 of the liquid ejection head 34, a suction pump 20 for creating negative pressure within the cap 82a, a tube member 19 having one end connected to the cap 82a and a hollow needle-like member 120 at the other end, for guiding waste liquid discharged into the cap 82a, and a nozzle 120 detachably connected to the tube member 19 for storing the waste liquid. The device is equipped with a waste liquid tank (replacement waste liquid tank 101) and a waste liquid tank mounting section 140 for mounting the waste liquid tank in a replaceable manner. The waste liquid tank mounting section 140 is capable of mounting a vacuum waste liquid tank 100 having a sealing member 118 that seals the tank so as to maintain a negative pressure state inside and that can be pierced by a needle-shaped member 120. When the suction pump 20 is not driven, a negative pressure is created inside the cap 82a by piercing the sealing member 118 of the mounted vacuum waste liquid tank 100, and the waste liquid is sucked into the vacuum waste liquid tank 100.

[0058] The opening of the needle-shaped member 120 of the tube member 19 is preferably provided on the side of the needle-shaped member 120, since if the opening is provided at the tip, when the sealing member 118 is penetrated, part of the sealing member 118 may become caught in the opening, causing the needle-shaped member 120 to become clogged.

[0059] In the apparatus for discharging a liquid according to this embodiment, when the atmospheric pressure is V0, the pressure in the head tank 35 is V1, the pressure in the cap 82a is V2, and the pressure in the vacuum waste liquid tank 100 in a sealed state is V3, the negative pressure of the vacuum waste liquid tank 100 to be mounted satisfies the relationship of V3 < V2 < V1 < V0. Due to the negative pressure of the vacuum waste liquid tank 100, it becomes possible to suck the liquid in the head tank 35 and the liquid in the liquid discharge head 34.

[0060] Also, the suction amount of the waste liquid can be changed according to the internal pressure of the vacuum waste liquid tank 100 to be mounted. According to the capacity of the head tank 35, the properties (viscosity) of the liquid, etc., and according to the assumed amount of waste liquid, etc., by appropriately selecting the negative pressure (degree of vacuum) of the vacuum waste liquid tank 100, nozzle suction according to the purpose and recovery of the waste liquid can be performed.

[0061] In the apparatus for discharging a liquid according to this embodiment, in the waste liquid tank mounting portion 140, when the suction pump 20 can be driven, an exchange waste liquid tank 101 having an air communication port is mounted, and when the suction pump 20 cannot be driven, the vacuum waste liquid tank 100 is mounted instead of the exchange waste liquid tank 101. In an image forming apparatus as an embodiment of the apparatus for discharging a liquid, an exchange waste liquid tank 101 is usually mounted in the waste liquid tank mounting portion 140 (see FIG. 6). On the other hand, when the suction pump 20 cannot be driven due to a failure of the apparatus or when the power is off, etc., the exchange waste liquid tank 101 can be removed and the vacuum waste liquid tank 100 can be mounted as shown in FIG. 9 to perform nozzle suction.

[0062] Furthermore, the nozzle suction method of the present invention is a method of performing nozzle suction in a liquid ejection device that includes a liquid ejection head 34 having a nozzle that ejects liquid, a head tank 35 that supplies liquid to the liquid ejection head 34, a cap 82a that caps the nozzle surface 23 of the liquid ejection head 34, a suction pump 20 that creates negative pressure within the cap 82a, and a tube member 19 that is connected to the cap 82a at one end and has a hollow needle-shaped member 120 at the other end, and that guides waste liquid discharged into the cap 82a, in which a vacuum waste liquid tank 100 is attached that seals so as to maintain a negative pressure state inside and is equipped with a sealing member 118 that can be pierced by the needle-shaped member 120, and the needle-shaped member 120 is pierced through the sealing member 118 to create negative pressure inside the cap 82a, and the liquid in the liquid ejection head 34 and the head tank 35 is suctioned.

[0063] Next, the fixed waste liquid tank 200 will be described with reference to FIG. FIG. 10(A) is a perspective view showing an example of the fixed waste liquid tank 200, and FIG. 10(B) is a schematic cross-sectional view thereof.

[0064] The waste liquid generated during the maintenance and recovery operation includes waste liquid caused by idle ejection and by cleaning ink adhering to the wiper member 83 with the wiper cleaner portion 85 . In the above-described image forming apparatus, waste liquid from the cap 82 a is stored in the replacement waste liquid tank 101 or the vacuum waste liquid tank 100 , and waste liquid from the idle ejection and cleaning of the wiper member 83 is stored in the fixed waste liquid tank 200 .

[0065] The amount of waste liquid from idle discharge or cleaning of the wiper member is small, so the amount of waste liquid is relatively high. In this case, the accumulation of waste liquid can be reduced by discharging only low-viscosity waste liquid into the sealed space.

[0066] 10(A) and 10(B), the fixed waste liquid tank 200 is composed of a container body 411 and a lid member 412, and the lid member 412 is provided with an opening 413 through which waste liquid is poured. The container body 411 and the lid member 412 are sealed by welding or the like. A rib 414 is formed on the inside of the lid member 412 around the opening 413 toward the inside, and a space 415 for holding waste liquid is formed between the rib 414 and the inner wall surface of the container body 411.

[0067] When the waste liquid put into the fixed waste liquid tank 200 has a high viscosity, it becomes a deposit 431, but when the fixed waste liquid tank 200 is tilted while it still has enough fluidity to become the deposit 431, the waste liquid 430 is held in the space 415 by the ribs 414. This prevents the waste liquid from spilling out of the opening 413 of the fixed waste liquid tank 200 even if the image forming apparatus is tilted slightly when moving the image forming apparatus.

[0068] When an image forming device is transported, if the image forming device is tilted during transportation, waste liquid may spill from the opening of the fixed waste liquid tank, causing damage to the inside of the device. For dye inks, etc., an absorbent member is placed at the waste liquid drip position, so that the waste liquid permeates the absorbent member and is retained by the absorbent member, preventing the waste liquid from spilling from the fixed waste liquid storage tank even if the image forming device is tilted.

[0069] However, when using quick-drying ink, if an absorbing member is placed at the waste liquid drip position, the ink will dry out before it can be absorbed by the absorbing member, and a film of thickened waste liquid will form on the upper surface of the absorbing member, making it impossible to absorb the waste liquid thereafter. Therefore, when the image forming device is tilted, waste liquid that has not been absorbed by the absorbing member may spill from the waste liquid tank through the opening. In this case, it is possible to consider a configuration in which an absorbing member is not provided in the waste liquid dripping area, but is provided outside the waste liquid dripping area, but this configuration would reduce the volume of the waste liquid tank. Therefore, this fixed waste liquid tank 200 is not provided with an absorbent member, but is configured to directly receive the waste liquid, and ribs 414 are provided around the opening 413 to form a space 415 that can hold the waste liquid and prevent it from spilling.

[0070] In addition, in the fixed waste liquid tank 200, a rib 421 is formed on the outside of the cover member 412 around the opening 413 facing outward, and the rib 421 reduces scattering of waste liquid mist during idle discharge and the like.

[0071] A fixed waste liquid tank 200 according to another embodiment is shown in schematic cross-sectional views in FIG. 10(C) and FIG. 10(D).

[0072] 10(C) has an absorbing member 416 disposed and held within space 415. This makes it difficult for waste liquid to spill out from the gap between container body 411 and lid member 412 even if the degree of adhesion between container body 411 and lid member 412 is reduced, eliminating the need for processes such as welding and reducing manufacturing costs.

[0073] 10(D), a rib 417 is formed around the entire circumference between the bottom surface of the container body 411 and the space for storing the waste liquid. By providing this rib 417, when the fixed waste liquid tank 200 is tilted, the rib 417 acts as a resistance, making it difficult for the waste liquid to flow.

[0074] With the above configuration, the liquid ejection device according to the present invention can perform nozzle suction even when the suction pump cannot be driven, and can prevent damage caused by leakage of liquid remaining in the liquid ejection head or head tank. In particular, when recovering a broken device, it is possible to prevent damage caused by leakage of liquid due to vibration during transportation or tilting of the device, and the like, and the work efficiency during repair is also improved.

[0075] In addition to the image forming apparatus (inkjet printer) described as one embodiment, the present invention can also be applied to an apparatus that discharges a liquid other than ink, such as a resist or a DNA sample in the medical field.

[0076] Aspects of the present invention are as follows, for example. <1> A liquid discharge head having nozzles for discharging a liquid, A head tank for supplying the liquid to the liquid discharge head, A cap for capping the nozzle surface of the liquid discharge head, A suction pump for forming a negative pressure in the cap, A tube member having one end connected to the cap and a hollow needle-like member at the other end, for guiding the waste liquid discharged into the cap, A waste liquid tank mounting portion detachably connected to the tube member and interchangeably mounting a waste liquid tank for storing the waste liquid, The waste liquid tank mounting portion can mount a vacuum waste liquid tank provided with a seal member that seals to maintain an internal negative pressure state and allows the needle-like member to penetrate therethrough, When the suction pump is not driven, a negative pressure is formed in the cap by piercing the seal member of the mounted vacuum waste liquid tank with the needle-like member, and the waste liquid is sucked into the vacuum waste liquid tank. The apparatus is characterized by discharging a liquid. <2> When the atmospheric pressure is V0, the pressure in the head tank is V1, the pressure in the cap is V2, and the pressure in the sealed vacuum waste liquid tank is V3, the relationship V3 < V2 < V1 < V0 is satisfied, The apparatus for discharging a liquid according to <1> above, characterized in that the liquid in the head tank and the liquid in the liquid discharge head are sucked by the negative pressure of the vacuum waste liquid tank. <3> The apparatus for discharging a liquid according to <1> or <2> above, characterized in that the suction amount of the waste liquid can be changed according to the internal pressure of the vacuum waste liquid tank. <4> The waste liquid tank mounting portion is provided with a replacement waste liquid tank having an air communication port when the suction pump is operable, and the vacuum waste liquid tank is mounted in place of the replacement waste liquid tank when the suction pump is inoperable. <1> from <3> 1 is a liquid ejection device according to any one of claims 1 to 9. <5> a liquid ejection head having a nozzle for ejecting liquid; a head tank for supplying liquid to the liquid ejection head; a cap for capping a nozzle surface of the liquid ejection head; a tube member having one end connected to the cap and the other end having a hollow needle-shaped member for guiding waste liquid discharged into the cap, This vacuum waste liquid tank is characterized in that it is equipped with a sealing member that can be pierced by the needle-shaped member and that seals the tank so as to maintain a negative pressure state inside, and when the needle-shaped member is pierced through the sealing member, negative pressure is created within the cap and the waste liquid is sucked in. <6> a liquid ejection head having a nozzle for ejecting liquid; a head tank for supplying liquid to the liquid ejection head; a cap for capping a nozzle surface of the liquid ejection head; a tube member having one end connected to the cap and the other end having a hollow needle-shaped member, and guiding waste liquid discharged into the cap, This nozzle suction method is characterized by attaching a vacuum waste liquid tank that is sealed so as to maintain an internal negative pressure state and has a sealing member that can be pierced by the needle-shaped member, and by piercing the needle-shaped member through the sealing member, negative pressure is created within the cap, and liquid within the liquid ejection head and the head tank is sucked in. [Explanation of symbols]

[0077] 19 Tube material 20 Suction Pump 22 Nozzle 23 Nozzle surface 34 Liquid ejection head 35 Head Tank 81 Maintenance and Recovery Mechanism 82a Cap (suction cap) 82b Cap (moisturizing cap) 83 Wiper parts 84 Empty discharge receiver 100 Vacuum waste tank 101 Replacement waste tank 118 Sealing material 120 Needle-shaped member 200 Fixed waste tank [Prior art documents] [Patent documents]

[0078] [Patent Document 1] Patent No. 5472495

Claims

1. a liquid ejection head having a nozzle for ejecting liquid; a head tank for supplying liquid to the liquid ejection head; a cap for capping a nozzle surface of the liquid ejection head; a suction pump that creates a negative pressure in the cap; a tube member having one end connected to the cap and a hollow needle-shaped member at the other end, for guiding waste liquid discharged into the cap; a waste liquid tank mounting section for mounting a waste liquid tank that is detachably connected to the tube member and that stores the waste liquid in a replaceable manner, the waste liquid tank mounting section is capable of mounting a vacuum waste liquid tank having a seal member that can be sealed to maintain a negative pressure state therein and that can be pierced by the needle-shaped member; A liquid discharging device characterized in that, when the suction pump is not driven, the needle-shaped member is pierced through the sealing member of the attached vacuum waste liquid tank to create negative pressure within the cap, and the waste liquid is sucked into the vacuum waste liquid tank.

2. When the atmospheric pressure is V0, the pressure inside the head tank is V1, the pressure inside the cap is V2, and the pressure inside the vacuum waste liquid tank in a sealed state is V3, the relationship V3<V2<V1<V0 is satisfied, 2. The liquid ejection device according to claim 1, wherein the liquid in the head tank and the liquid in the liquid ejection head are sucked by negative pressure in the vacuum waste liquid tank.

3. 3. The liquid discharging device according to claim 1, wherein the amount of the waste liquid suctioned is variable in accordance with the internal pressure of the vacuum waste liquid tank.

4. 3. The liquid discharging device according to claim 1, wherein a replacement waste liquid tank having an atmosphere communication port is mounted to the waste liquid tank mounting section when the suction pump is operable, and when the suction pump is inoperable, the vacuum waste liquid tank is mounted in place of the replacement waste liquid tank.

5. a liquid ejection head having a nozzle for ejecting liquid; a head tank for supplying liquid to the liquid ejection head; a cap for capping a nozzle surface of the liquid ejection head; a tube member having one end connected to the cap and the other end having a hollow needle-shaped member for guiding waste liquid discharged into the cap, the waste liquid tank being attached to a device for discharging liquid, A vacuum waste liquid tank comprising a sealing member that is capable of sealing the cap so as to maintain a negative pressure state inside and that is pierceable by the needle-shaped member, and when the needle-shaped member is pierced through the sealing member, a negative pressure is created within the cap and the waste liquid is sucked in.

6. a liquid ejection head having a nozzle for ejecting liquid; a head tank for supplying liquid to the liquid ejection head; a cap for capping a nozzle surface of the liquid ejection head; a tube member having one end connected to the cap and the other end having a hollow needle-shaped member, and guiding waste liquid discharged into the cap, A nozzle suction method comprising: attaching a vacuum waste liquid tank having a sealing member that is sealed so as to maintain a negative pressure state inside and that can be pierced by the needle-shaped member; piercing the needle-shaped member through the sealing member to create negative pressure inside the cap; and suctioning liquid from the liquid ejection head and the head tank.

Images