JP2008213314A - Liquid jet apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid jet apparatus which can prevent the occurrence of a malfunction, caused by the mixing of gas into a liquid supply path, by discharging the gas, mixed into the liquid supply path, through the use of a simple constitution, even if a cleaning operation is not frequently performed. <P>SOLUTION: This liquid jet apparatus comprises pressurization mechanisms 10 (10a-10f) for pumping ink in an ink pack as a liquid storage member to a recording head 6 side, and an on-off valve which is arranged midway through the ink supply path so as to open/close the ink supply path. The pressurization mechanism performs pressurization at any time including the time of the nonoperation of a printer 1, so that the internal pressure of the ink supply path from the ink pack to the on-off valve via a supply tube 8 can be kept higher than the external pressure of the ink supply path. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid ejecting apparatus such as an ink jet printer, and in particular, introduces a liquid stored in a liquid storage member into a pressure chamber via a liquid supply path, and introduces the liquid introduced into the pressure chamber from a nozzle opening. The present invention relates to a liquid ejecting apparatus including a liquid ejecting head that ejects droplets.

  A typical example of a liquid ejecting apparatus that includes a liquid ejecting head capable of ejecting liquid and ejects various liquids from the liquid ejecting head is, for example, for recording paper as an ejection target (recording medium) An image recording apparatus such as an ink jet printer that performs recording by discharging and landing ink droplets can be given. In recent years, it is applied not only to this image recording apparatus but also to various manufacturing apparatuses. For example, in a display manufacturing apparatus such as a liquid crystal display, a plasma display, an organic EL (Electro Luminescence) display, or an FED (surface emitting display), various liquid materials such as coloring materials and electrodes are used for pixel formation regions and electrode formation. A liquid ejecting apparatus is used for discharging to an area or the like.

  In the liquid ejecting apparatus, a liquid supply source (ink cartridge) is arranged on the apparatus main body side, and a relay unit (pressure during ink supply) for introducing ink from the liquid supply source into the liquid ejecting head is provided. It also functions as a pressure regulating valve for controlling fluctuations.) Is mounted on the liquid ejecting head, and these liquid supply source and the relay unit are connected by a flexible liquid supply tube, and the liquid is supplied through this liquid supply tube. A configuration (so-called off-carriage type) that supplies ink from a supply source into the liquid ejecting head is employed (Patent Document 1).

  In such a configuration, it is ideal that the ink flow path (liquid supply path) from the ink cartridge to the nozzle opening of the recording head is filled only with ink. It is difficult to prevent. In particular, in the off-carriage type that supplies ink from the ink cartridge to the inside of the liquid ejecting head via the liquid supply tube, external air permeates the wall of the liquid supply tube and other structures and dissolves in the internal ink. Bubbles may be generated in the ink in the ink flow path. Bubbles in the ink flow path gradually grow and become large, and when excessively grown bubbles move to the pressure chamber side due to the flow of ink, pressure loss due to absorption of pressure fluctuations during discharge operation, and bubbles May cause problems such as insufficient ink supply due to blockage of the flow path.

In order to prevent such a malfunction due to the mixing of bubbles, the above-described liquid ejecting head periodically performs a cleaning operation for generating an ink flow having a flow rate several times that during the recording operation, and the bubbles in the ink flow path Is discharged. In order to discharge the gas mixed in the ink other than the cleaning operation, a gas permeable film is provided on the side surface of the common liquid chamber (common liquid chamber) communicating with the pressure chamber, and the liquid of the gas permeable film is It has been proposed that a chamber is provided on the side opposite to the side in contact with the chamber, and a negative pressure is generated in the chamber to degas the liquid in the common liquid chamber, thereby suppressing the generation of bubbles in the pressure chamber ( Patent Document 2).
JP 2005-219229 A JP 2006-95878 A

  However, in the configuration of the invention of Patent Document 2, the gas in the common liquid chamber cannot be degassed through the gas permeable membrane unless the pressure difference between the common liquid chamber and the chamber is increased. In order to obtain the defoaming ability, a large pressure reduction means is required. In addition, if this pressure difference is too large, the water vapor mixed in the ink will escape and the ink in the ink flow path will thicken, so the pressure in the chamber is controlled while monitoring using a pressure gauge or the like. There was a need to do. In addition, a gas permeable film made of a fluorine-based thin film or a silicon-based thin film has a problem that the transmittance is reduced when ink is spread. Furthermore, if air bubbles are inadvertently mixed into the ink flow path when the ink cartridge is not sufficiently deaerated in the common liquid chamber, the air bubbles enter the adjacent pressure chamber before melting into the ink, causing a problem. There was a fear.

  The present invention has been made in view of such circumstances, and an object of the present invention is to discharge the gas mixed in the liquid supply path with a simple configuration without frequently performing a cleaning operation. An object of the present invention is to provide a liquid ejecting apparatus capable of preventing the occurrence of problems caused by mixing.

The liquid ejecting apparatus of the present invention has been proposed in order to achieve the above object, and supplies the liquid stored in the liquid storing member to the liquid ejecting head through the liquid supply path, and the supplied liquid is liquid. A liquid ejecting apparatus configured to be ejected by an ejecting head,
A pressurizing means for pumping the liquid in the liquid storage member to the liquid ejecting head side, and an on-off valve disposed in the middle of the liquid supply path for opening and closing the liquid supply path,
The pressurizing unit constantly pressurizes the liquid ejecting apparatus even when the liquid ejecting apparatus is not in operation, thereby reducing the internal pressure of the liquid supply path from the liquid storage member to the on-off valve via the liquid supply path. It is characterized by maintaining a state higher than the external pressure.

  According to the above configuration, the pressurizing unit for pumping the liquid in the liquid storage member to the liquid ejecting head side constantly pressurizes the liquid from the liquid storage member even when the liquid ejecting apparatus is not operating. Since the internal pressure of the liquid supply path from the supply path to the on-off valve is maintained higher than the pressure outside the liquid supply path, the gas mixed in the liquid supply path can be discharged to the outside, It is possible to suppress the gas from entering the liquid supply path. For this reason, it is possible to prevent as much as possible a problem that occurs due to air bubbles mixed into the liquid ejecting head side. As a result, since the frequency of execution of the cleaning operation for discharging bubbles can be reduced, it is possible to reduce the consumption of liquid accompanying the cleaning operation.

  In this configuration, it is preferable that at least a part of the liquid supply path from the liquid storage member to the on-off valve is configured by a liquid supply member manufactured using a material having gas permeability.

  According to this configuration, at least a part of the liquid supply path is configured by the liquid supply member manufactured using the gas permeable material, so that the bubble discharging function by the constant pressurization of the pressurizing unit is more reliably performed. Can be secured.

Further, in the above configuration, an upstream trap empty portion capable of capturing gas mixed in the liquid is provided upstream of the on-off valve in the liquid supply path,
At least a part of the partition wall that divides the upstream trap space is allowed to permeate the gas in the upstream trap space to the outside of the upstream trap space by the pressure difference between the inside and outside of the upstream trap space by the pressurizing means. It is desirable to have a possible permeable partition wall.

  According to this configuration, the upstream trap cavity is provided upstream of the on-off valve in the liquid supply path, and at least a part of the partition wall that partitions the upstream trap cavity is disposed upstream of the pressurizing unit. Because the gas in the upstream trap cavity is permeable to the outside of the upstream trap cavity due to the pressure difference between the inside and outside of the trap cavity, the gas mixed in the liquid supply path is transferred to the upstream trap cavity. The trapped gas can be discharged to the outside of the liquid supply path through the permeation section wall by pressurization by the pressurizing means. For this reason, it becomes possible to raise bubble discharge capability more.

In each of the above configurations, the transmission partition wall is integrally formed using the same material as the other partition walls partitioning the upstream trap space, and is configured to be thinner than the other partition walls. can do.
Moreover, you may employ | adopt the structure which forms the said permeation | separation division wall using the material whose gas permeability is higher than the other division wall which divides the upstream trap empty part.

In each of the above configurations, an upstream discharge void is formed outside the permeation partition wall in the upstream trap void, and the pressure in the upstream discharge void is reduced compared to the pressure in the upstream trap void. Upstream pressure reducing means
Due to the pressure difference between the upstream trap empty space and the upstream discharge empty space by the pressurizing means and the upstream depressurizing means, the gas in the upstream trap empty space permeates the permeation partition wall into the upstream discharge empty space. It is desirable to discharge.

  According to this configuration, due to the pressure difference between the upstream trap empty space and the upstream discharge empty space between the pressurizing means and the upstream depressurizing means, the gas in the upstream trap empty space permeates the permeation partition wall and is discharged upstream. Since it discharges to the empty part, it becomes possible to further enhance the bubble discharging ability.

In each of the above-described configurations, a downstream trap cavity that can capture gas mixed in the liquid is formed between the on-off valve and the liquid jet head,
At least a part of the partition wall that partitions the downstream trap space, a permeation partition wall that allows gas in the downstream trap space to permeate to the outside of the downstream trap space due to a pressure difference between the inside and outside of the downstream trap space age,
Forming a downstream discharge void outside the permeation partition wall in the downstream trap void,
Downstream pressure reducing means for lowering the pressure in the downstream discharge empty portion compared to the pressure in the downstream trap empty portion,
Due to the pressure difference between the downstream trap empty space and the downstream discharge empty space by the downstream pressure reducing means, the gas in the downstream trap empty space passes through the permeation partition wall and is discharged to the downstream discharge empty space side. It is desirable to configure.

  According to this configuration, due to the pressure difference between the downstream trap space and the downstream discharge space by the downstream decompression means, the gas in the downstream trap space permeates the permeation partition wall and the downstream discharge space side. Therefore, bubbles generated between the on-off valve and the downstream trap space can be discharged. Thereby, it is possible to more reliably prevent bubbles from entering the liquid ejecting head side.

Further, in each of the above configurations, a carriage for mounting the liquid jet head is provided,
It is desirable to employ a configuration in which the on-off valve is provided on the carriage.

  According to this configuration, since the on-off valve is provided on the carriage so that the on-off valve is as close as possible to the liquid ejecting head, a range in which bubbles cannot be discharged by pressurization by the pressurizing unit (that is, The path from the on-off valve to the liquid jet head can be made as short as possible. Thereby, it becomes possible to discharge | emit the bubble of a liquid supply path more effectively.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In the embodiments described below, various limitations are made as preferred specific examples of the present invention. However, the scope of the present invention is not limited to the following description unless otherwise specified. However, the present invention is not limited to these embodiments. In the present embodiment, an ink jet printer (hereinafter simply referred to as a printer) typified by an image recording apparatus that is one form of the liquid ejecting apparatus will be described as an example.

  FIG. 1 is a perspective view illustrating a schematic configuration inside the printer, and FIG. 2 is a schematic diagram illustrating the internal configuration of the printer. The printer 1 includes a housing 2, a paper feed tray 3, and a paper discharge tray 4. The housing 2 is a member that covers the entire printer 1 as an outer shell. A paper feed tray 3 is provided in the upper part of the housing 2, and a paper discharge tray 4 is provided in the lower front part of the housing 2. A recording sheet as a printing target (ink droplet ejection target) is set in the paper feed tray 3. Then, the recording paper set in the paper feed tray 3 is sent out to the platen 14 side inside the printer 1 along a direction (sub scanning direction) indicated by X in FIG. 1 by a paper feeding mechanism (not shown). Yes. The paper discharge tray 4 guides and discharges the recording paper printed inside the printer to the outside of the printer 1.

  Inside the printer 1, a guide rod 5 is installed along the longitudinal direction (left-right direction) of the housing 2. A carriage 7 on which a recording head 6 and an ink pressure adjusting unit 45 described later are mounted is supported on the guide rod 5 so as to be movable. The carriage 7 is connected to a drive motor (pulse motor) (not shown) via a drive belt. When the drive motor is driven to rotate, the driving force is transmitted via the drive belt so that the carriage 7 reciprocates in the direction along the guide rod 5, that is, in the main scanning direction (direction indicated by Y in FIG. 1). It has become.

  The ink pressure adjustment unit 45 of the carriage 7 is in a liquid-tight state with a first ink cartridge C1 (hereinafter abbreviated as first cartridge C1) via a supply tube 8a connected to the upstream communication port 13. Connected with. A pack storage chamber 9a is defined inside the first cartridge C1, and an ink pack (a type of liquid storage member) in which black ink which is a type of the liquid of the present invention is stored in the pack storage chamber 9a. B is housed. The ink pack B is formed in a bag shape by a flexible sheet or the like, and stores the black ink stored therein so that it can be led out through the supply tube 8a. Further, the ink supply path from the ink pack B through the supply tube 8a and the communication channel 47 (described later) to the on-off valve 48 (described later) is pressed into the pack storage chamber 9a. A pressurizing mechanism 10a for pressurizing the (liquid supply path) is disposed.

  The pressure mechanism 10a includes a pressing plate 11 for pressing the ink pack B and an urging member 12 that urges the pressing plate 11 toward the ink pack B. The pressing plate 11 in the present embodiment is a plate material having a shape that is slightly smaller than the planar shape of the pack housing chamber 9a, and is made of, for example, metal or synthetic resin. The urging member 12 is composed of a coil spring or the like, and is disposed between the ceiling surface of the pack housing chamber 9 a and the pressing plate 11. When the ink pack B is pressurized by the pressure mechanism 10a, the black ink stored in the ink pack B is pressure-fed to the carriage 7 side through the supply tube 8a. The pressurizing mechanism 10a pressurizes the ink pack B at all times including when the printer 1 is not operating (when the power is off). Thereby, the ink supply path from the ink pack B to the opening / closing valve 48 through the supply tube 8a and the communication channel 47 is maintained in a pressurized state.

  Inside the printer 1, in addition to the first cartridge C1, a second ink cartridge C2 (hereinafter abbreviated as a second cartridge C2) is disposed. As shown in FIG. 2, a total of five pack storage chambers 9b to 9f are partitioned inside the second cartridge C2, and each pack storage chamber 9b to 9f has cyan, magenta, yellow, light cyan, and light cyan. Ink packs C, M, Y, LC, and LM storing respective magenta inks are accommodated. Each of the ink packs C, M, Y, LC, and LM is formed into a bag shape by a flexible sheet like the ink pack B, and is in a liquid-tight state at the upstream communication port 13 of the carriage 7 through the supply tubes 8b to 8f. It is connected.

  Further, in each of the pack storage chambers 9b to 9f, similarly to the pack storage chamber 9a, the corresponding ink pack is pressed, and ink is supplied from the ink pack through the supply tube 8 to the on-off valve 48. Pressurizing mechanisms 10b to 10f for pressurizing the path are disposed. These pressure mechanisms 10b to 10f are composed of a pressing plate 11 and an urging member 12 similarly to the pressure mechanism 10a, and pressurize the ink pack to supply ink stored in the ink pack to the supply tube 8. Through the carriage 7 side. The pressurizing mechanisms 10b to 10f are configured to pressurize the corresponding ink packs at all times, including when the printer 1 is not operating (when the power is off). Thereby, the ink supply path from each ink pack to the opening / closing valve 48 through the supply tube 8 and the communication channel 47 is maintained in a pressurized state.

  The supply tube 8 is a member that functions as a liquid supply member in the present invention, and is made of a gas-permeable material, for example, an olefin-based or styrene-based thermoplastic elastomer. The reason why the supply tube 8 is made of such a material is to enhance the effect of eliminating bubbles in the ink supply path. Details of this point will be described later.

  Next, the recording head 6 mounted on the printer 7 will be described. FIG. 3 is a cross-sectional view of the main part of the recording head 6. The recording head 6 in the present embodiment is schematically configured to include a head case 20, a vibrator unit 21, a flow path unit 22, and the like.

  The head case 20 is a hollow box-like member, the flow path unit 22 is fixed to the front end surface (lower surface), and the vibrator unit 21 is accommodated in the accommodation space 23 formed inside. Yes. The head case 20 is formed with a case flow path 31 that penetrates the case height direction. The upstream end of the case flow path 31 communicates with a downstream communication port 15 of an ink pressure adjustment unit 45 described later, and the downstream end of the case flow path 31 communicates with a common ink chamber 30 of the flow path unit 21. .

  The vibrator unit 21 includes a plurality of piezoelectric vibrators 24 (one type of pressure generating means) arranged in a comb-teeth shape, and a wiring member (not shown) for supplying a drive signal to the piezoelectric vibrators 24. And a fixed substrate 25 for fixing the piezoelectric vibrator 24 and the like. The piezoelectric vibrator 24 is joined to a flexible surface (vibrating plate) that partitions the pressure chamber 26 in the flow path unit 22. The piezoelectric vibrator 24 is expanded and contracted by supplying a drive signal to expand or contract the volume of the pressure chamber 26, thereby causing a pressure variation in the ink in the pressure chamber 26, and controlling the pressure variation. Ink droplets can be ejected from the nozzle openings 27.

  The flow path unit 22 is integrally joined with an adhesive in a state in which constituent members such as a nozzle formation substrate 28 having a nozzle row in which nozzle openings 27 are arranged and a flow path formation substrate 29 that forms an ink flow path are laminated. This is a unit member that forms a series of ink flow paths from the common ink chamber 30 (common liquid chamber) through the ink supply port and the pressure chamber 26 to the nozzle opening 27. The pressure chamber 26 in the flow path unit 22 is formed for each nozzle opening 27 and is configured such that ink is supplied from the ink pressure adjustment unit 45 side of the carriage 7 through the common ink chamber 30.

  The printer 1 conveys the recording paper along the sub-scanning direction X, and reciprocates the carriage 7 along the main scanning direction Y, while generating an image signal (dot pattern data) generated based on the print data. ) Drives the piezoelectric vibrator 24 to eject ink droplets from the recording head 6. As a result, the printer 1 records an image or text on the recording paper.

  Inside the printer 1, a home position where the carriage 7 is arranged in a printing pause state is provided in one side area (lower right part in FIG. 1) that is out of the printing area (upper surface of the platen 14). . A capping mechanism 34 is disposed at this home position. The capping mechanism 34 includes a cap holder 35 (FIG. 2) that can be moved up and down by a lifting mechanism (not shown). A cap member 36 as a sealing means is disposed on the cap holder 35. The cap member 36 is a tray-like member having an upper surface opened, and is made of an elastic member such as an elastomer, for example.

  An absorbing material 37 made of a porous material for absorbing ink or the like is laid inside the cap member 36. Further, through holes 38 a and 38 b are formed in the bottom surface of the cap member 36. The through hole 38 a is connected to the suction pump 40 via the discharge tube 39. The suction pump 40 includes, for example, a tube pump that sends out fluid by handling the tube with a roller or the like, a gear pump that sends out fluid downstream by rotating a drive gear and a driven gear, and the like. Ink and air are sucked and discharged. A discharge tank (not shown) is connected to the downstream side of the suction pump 40, and ink, air, etc. sent out by the suction pump 40 are discharged to the discharge tank. An air release valve 42 is connected to the through hole 38b via an air release tube 41. The air release valve 42 opens the inside of the cap member 36 by opening the valve.

  When the carriage 7 moves to the home position, the cap holder 35 rises with the movement of the carriage 7 and seals the nozzle formation surface (nozzle formation substrate 28) of the recording head 6 with the cap member 35. When the pump 40 is operated in this sealed state, the inside of the cap member 35 becomes negative pressure, and the ink, bubbles, etc. thickened in the recording head 6 due to this negative pressure pass through the nozzle openings 27 to the inside of the cap member 35. It is discharged and cleaned. When the cleaning is completed, the air release valve 42 is opened and the negative pressure in the cap member 36 is released. Thereafter, the cap holder 35 is lowered and the cap member 35 is separated from the nozzle forming surface.

Next, the ink pressure adjustment unit 45 mounted on the carriage 7 and having the opening / closing valve 48 will be described.
FIG. 4 is a cross-sectional view illustrating the configuration of the ink pressure adjustment unit 45 in the present embodiment. The ink pressure adjustment unit 45 has a supply tube 8 connected to the upstream communication port 13, receives ink from the supply tube 8, and adjusts the supply pressure of the ink by a pressure adjustment valve while adjusting the pressure of the recording head 6. It is a member introduced to the chamber 26 side. The ink pressure adjustment unit 45 in this embodiment has a communication channel 47 that communicates the supply tube 8 and the case channel 31 of the head case 20 inside the unit main body 46 (housing). A total of six communication channels 47 are provided for each ink.

  In the middle of each communication channel 47, an on-off valve 48 for opening and closing the communication channel 47 and a pressure adjusting chamber 49 formed on the downstream side of the on-off valve 48 are provided. The on-off valve 48 and the pressure adjustment chamber 49 are parts that function as a pressure adjustment valve. The pressure adjustment chamber 49 is a recess formed in a state of being recessed from one side surface (upper surface) to the other side surface (lower surface) of the unit main body 46, and at the bottom of one end side in the longitudinal direction (right side in FIG. 4). Is provided with an introduction port 51, and a discharge port 52 is formed at the bottom of the other end side (left side in FIG. 4). The opening surface of the pressure adjusting chamber 49 is sealed with a flexible film 53. The film 53 is thermally welded to the peripheral edge portion of the opening surface of the pressure adjusting chamber 49 and functions as a pressure receiving portion. When the internal pressure of the pressure adjustment chamber 49 decreases, the film 53 is bent toward the bottom side of the pressure adjustment chamber 49.

  FIG. 5 is an enlarged cross-sectional view for explaining the configuration in the vicinity of the on-off valve 48. FIG. 5A shows a state in which the on-off valve 48 closes the introduction port 51 that is a part of the communication channel 47. Indicates a state in which the opening / closing valve 48 opens the inlet 51. The on-off valve 48 includes a columnar shaft portion 57, a substantially disk-shaped flange portion 58 extending laterally from the middle of the longitudinal direction of the shaft portion 57, and the upper surface side of the flange portion 58 (pressure adjusting chamber 49 And a packing 59 disposed on the side), and is disposed in a storage chamber 55 formed below (upstream side) the introduction port 51. The distal end portion of the shaft portion 57 (the distal end side with respect to the flange portion 58) is formed so that the outer diameter thereof is smaller than the inner diameter of the introduction port 51, and is inserted into the pressure adjustment chamber 49 through the introduction port 51. Ink from the upstream communication port 13 side is introduced into the pressure adjustment chamber 49 through a gap between the shaft portion 57 and the inner peripheral surface of the introduction port 51. The packing 59 is formed in an approximately donut shape, for example, by an elastic member such as an elastomer, the outer diameter of which is smaller than the outer diameter of the flange portion 58 and the inner diameter of which is larger than the outer diameter of the shaft portion 57.

  Further, the accommodating chamber 55 is provided with a plate spring 56 in a cantilever state with one end fixed. The leaf spring 56 is made of, for example, a stainless steel plate having elasticity, and comes into contact with a base end portion of the on-off valve 48 (a portion on the side opposite to the tip portion on the pressure adjusting chamber 49 side). 48 is urged toward the pressure adjustment chamber side 49, and the closed state is maintained until the pressure adjustment chamber 49 is depressurized to a predetermined pressure. That is, the opening / closing valve 48 urged toward the ceiling surface side of the storage chamber 55 by the leaf spring 56 is in close contact with the peripheral portion of the introduction port 51 unless the stress is resisted by the elastic force of the leaf spring 56. The valve is held in the closed position. At this valve closing position, the on-off valve 48 blocks ink from flowing into the pressure adjustment chamber 49 (the state shown in FIG. 5A).

  When the inflow of ink into the pressure adjustment chamber 49 is blocked by the opening / closing valve 48, the internal pressure of the pressure adjustment chamber 49 gradually decreases due to ink consumption by the recording head 6. When the pressure adjustment chamber 49 is depressurized to a predetermined pressure (minimum pressure at which the recording head 6 does not interfere with ink ejection), the film 53 serving as a pressure receiving portion moves toward the bottom side of the pressure adjustment chamber 49. To displace. Then, the film 53 presses the distal end portion of the shaft portion 57 of the on-off valve 48 and moves the on-off valve 48 downward while resisting the elastic force of the leaf spring 56. As a result, the opening / closing valve 48 is displaced to a position (opening position) where the packing 59 is separated from the peripheral edge of the introduction port 51 and the close contact state is released (the state shown in FIG. 5B). In this valve opening position, ink is allowed to flow into the pressure adjustment chamber 49 through the introduction port 51. When ink is introduced into the pressure adjustment chamber 49, the internal pressure of the pressure adjustment chamber 49 is increased from the minimum pressure. When the internal pressure of the pressure adjustment chamber 49 is increased, the film 53 is displaced toward the upper side of the pressure adjustment chamber 49. As a result, the opening / closing valve 48 is moved upward by the elastic force of the leaf spring 56, and is again displaced to the valve closing position to block the inflow of ink into the pressure adjusting chamber 49 (state shown in FIG. 5A).

  In this way, the pressure regulating valve reduces the pressure of the ink supplied to the recording head 6 to a certain pressure by the reciprocating movement between the valve closing position and the valve opening position of the on-off valve 48, and the ink ejection failure Avoid excessive pressure boosting. This pressure regulating valve (open / close valve 48) is in the closed position and closes the ink supply path unless the pressure regulating chamber 49 is depressurized to a predetermined pressure. For this reason, when the ink pack is pressurized by the pressurizing mechanism 10, the internal pressure of the ink supply path from the ink pack to the open / close valve 48 at the valve closing position via the supply tube 8 and the communication flow path 47 becomes the ink supply path. It is maintained in a state higher than the external pressure (atmospheric pressure), that is, in a pressurized state.

  The above pressurized state is maintained even when the printer 1 is turned off (during non-operation) (that is, because it is constantly pressurized), so that the gas mixed in the ink supply path is supplied to the supply tube 8. Can be gradually discharged to the outside of the ink supply path through the wall surface of the unit and the wall surface of the unit body 46. On the contrary, it is possible to prevent the external gas from entering the ink supply path through the wall surface of the supply tube 8 or the like. For this reason, it is possible to prevent as much as possible problems such as ejection failure caused by bubbles mixed into the recording head 6 side. As a result, since the frequency of execution of the cleaning operation for discharging bubbles can be reduced, it is possible to reduce the consumption of ink accompanying the cleaning operation.

  Further, the ink supply path from the ink pack through the supply tube 8 and the communication flow path 47 to the open / close valve 48 in the closed position is maintained in a pressurized state, whereby the packing 59 of the open / close valve 48 is introduced into the inlet 51. Therefore, the sealing performance with respect to the introduction port 51 can be further ensured. As a result, ink leakage due to poor sealing of the on-off valve 48 can be prevented.

  If the gas is discharged over a long period of time with a low pressure difference, there is no need to supply a large pressure, so there is no need for a large suction device equipped with a device for controlling the pressure, etc. A pressurizing means having a simple structure such as the pressurizing mechanism 10 for pressurizing the pack is sufficient. Thereby, it becomes possible to contribute to size reduction and cost reduction of the apparatus.

  In the present embodiment, the supply tube 8 is made of a gas permeable material, that is, at least a part of the ink supply path from the ink pack to the on-off valve 48 is gas permeable. Since the liquid supply member is manufactured using the material having the above, the bubble discharge effect can be enhanced.

  In this embodiment, the opening / closing valve 48 (ink pressure adjusting unit 45) is provided in the carriage 7 so that the opening / closing valve 48 is as close as possible to the recording head 6. The range in which bubbles cannot be discharged by pressurization (that is, the path from the on-off valve 48 to the recording head 6) can be made as short as possible. This makes it possible to more effectively discharge the bubbles in the ink supply path.

  Further, the ink pressure adjustment unit 45 in the present embodiment employs a configuration for further enhancing the bubble discharge effect. Hereinafter, this point will be described.

  In the ink pressure adjustment unit 45 in the present embodiment, as shown in FIG. 4, two filter chambers 61 and 62 are formed in the middle of the communication channel 47. Specifically, the upstream filter chamber 61 is formed in the communication channel 47 upstream of the on-off valve 48, that is, in the middle of the communication channel 47 from the upstream communication port 13 to the on-off valve 48. . A downstream filter chamber 62 is formed in the communication channel 47 downstream of the on-off valve 48, more specifically in the middle of the communication channel 47 from the outlet 52 to the downstream communication port 15. Yes.

  These filter chambers 61 and 62 are empty portions formed in a state in which the inner diameter of the communication channel 47 is enlarged to the extent that the filters 63 and 64 can be accommodated. The filters 63 and 64 are members for filtering ink in the communication flow path 47 (liquid supply path), and are formed by, for example, finely braiding metal into a mesh shape. The filters 63 and 64 in this embodiment also have a function of making it difficult for air bubbles mixed in the ink flow path to pass therethrough and capturing them in the empty portion of the filter chamber on the upstream side. Therefore, these filter chambers 61 and 62 also function as gas trap vacancies capable of capturing the gas mixed in the ink in the communication flow path 47 (ink supply path). That is, the upstream filter chamber 61 functions as an upstream trap space in the present invention, and the downstream filter chamber 62 functions as a downstream trap space in the present invention.

  Since the filter chambers 61 and 62 of the present embodiment are formed by enlarging the inner diameter of the communication channel 47 as described above, the ink flow rate is gentler than that of the portion having the smaller inner diameter. For this reason, it is possible to make it difficult to move the inflowing bubbles to the downstream side of the filters 63 and 64, and thus it is possible to capture the bubbles flowing in from the upstream side in the upper part of the filters 63 and 64. The upstream filter chamber 61 traps gas mixed mainly in the path from the ink pack to the upstream filter chamber 61 through the supply tube 8, and the downstream filter chamber 62 mainly includes the pressure adjustment chamber 49 ( In particular, the trapped gas is trapped via the film 53).

  In the printer 1 of the present embodiment, as shown in FIG. 4, a part of the partition wall that defines the upstream filter chamber 61 is made thinner than the other partition walls, and this thin part is used as the transmission partition wall. 65. The permeation partition wall 65 is provided to let the gas trapped in the upstream filter chamber 61 (upstream trap empty portion) escape to the outside of the filter chamber. Thereby, the gas mixed in the ink supply path is captured in the upstream filter chamber 61, and the captured gas is discharged to the outside of the ink supply path through the transmission partition wall 65 by pressurization by the pressurizing mechanism. be able to. For this reason, it becomes possible to raise bubble discharge capability more. Further, since foreign matter such as dust mixed in the ink supply path can be trapped by the filter 63, it is possible to prevent the foreign matter from entering between the peripheral portion of the inlet 51 and the on-off valve 48. This can suppress the sealing failure of the on-off valve 48.

  In the present embodiment, an upstream discharge empty portion 66 is further formed on the outer periphery of the upstream filter chamber 61 with the transmission partition wall 65 interposed therebetween. The upstream discharge empty portion 66 is configured to communicate with a decompression unit to be described later via a suction path 71 (see FIG. 6). Then, the gas (bubbles) inside the filter chamber permeates through the permeation partition wall 65 due to the pressure difference between the inside of the upstream filter chamber 61 and the outside (upstream discharge empty portion 66) and is discharged to the upstream discharge empty portion 66. I am doing so. The above pressure difference can be obtained only by pressurization by the pressurization mechanism 10, but in the present embodiment, in order to further enhance the bubble discharge effect, the pressure difference is generated by the two pressure difference applying means of the pressurization mechanism 10 and the decompression means. .

  Similarly to the upstream filter chamber 61, the downstream filter chamber 62 also has a permeation partition wall in which a part of the partition walls forming the filter chamber 62 is made thinner than the other partition walls. 68, and further, a downstream discharge cavity 69 is formed outside the downstream filter chamber 62 with the permeation partition wall 68 interposed therebetween. Similarly to the upstream discharge empty portion 66, the downstream discharge empty portion 69 is also configured to communicate with a decompression unit to be described later via the suction path 71. The downstream filter chamber 62 is configured to allow gas (bubbles) in the filter chamber to permeate the permeation partition wall 68 and discharge to the downstream discharge empty portion 69 by the pressure difference applied by the decompression means. ing.

The upper transmission partition walls 65 and 68 are made of the same material as the other partition walls partitioning the filter chambers 61 and 62, the communication flow path 47, etc., and are permeable to gas, such as POM (polyacetal), PP (Polypropylene), PPE (polyphenylene ether) and the like are integrally molded. Thereby, the process of separately molding and attaching the permeation partition walls 65 and 68 can be omitted, and the gas permeability can be enhanced as compared with other partition walls. In the present embodiment, based on the results of the experiment, it was found that the transmission efficiency is suitable when the area of the transmission partition walls 65 and 68 is about 1 cm ² and the thickness is about 1 mm. In addition, the material also has a gas permeability coefficient of 5 cc · mm / m ² · day · atm or more, and a moisture permeability coefficient of 2 g · mm / m ² · day · atm or less, which satisfies this condition. For example, materials other than the above materials can be used. Furthermore, the permeable partition walls 65 and 68 may be formed using a material having higher gas permeability than other partition walls.

  Next, a pressure reducing means for reducing the internal pressure of the discharge empty portions 66 and 69 to a low pressure compared with the internal pressure of the filter chambers 61 and 62 will be described. FIG. 6 is a diagram schematically showing a configuration for decompressing the filter chamber by the decompression means. This decompression means is commonly used for decompression of both the upstream discharge empty portion 66 and the downstream discharge empty portion 69. That is, this decompression means functions as an upstream decompression means and a downstream decompression means in the present invention. 6 shows a configuration for depressurizing the upstream discharge empty portion 66 for the sake of convenience, the configuration for depressurizing the downstream discharge empty portion 69 is also the same, and the description thereof is omitted.

  The pressure reducing means is provided in the carriage 7, and the piston pump 70 is operated by the movement of the carriage 7, so that the pressure in the upstream discharge empty portion 66 becomes lower than the pressure in the upstream filter chamber 61. Thus, the inside of the upstream discharge empty portion 66 can be decompressed. Further, for example, a stopper 72 capable of abutting the pressure receiving portion (the tip of the rod 78) of the piston pump 70 on the non-recording area on the other side opposite to the home position in the movement range of the carriage 7 described above. Is provided. As shown in FIG. 6, the piston pump 70 is arranged in such a manner that its longitudinal direction is along the scanning direction of the carriage 7, and communicates with the upstream discharge empty portion 66 (downstream discharge empty portion 69) via the suction path 71. Cylinder part 73, piston part 74 slidable in the cylinder longitudinal direction in cylinder part 73, and negative pressure generating chamber 75 formed by being surrounded by piston part 74 and cylinder part 73 and capable of changing capacity. A restoring spring 76 that urges the piston portion 74 so as to expand the volume of the negative pressure generating chamber 75, and a check valve 77 that allows the negative pressure generating chamber 75 to vent to the outside and prevents the reverse. And is configured. The tip of the rod 78 of the piston portion 74 protruding from the cylinder portion 73 can be brought into contact with the stopper 72 as a press receiving portion. The operation of this decompression means will be described in detail below.

  When a depressurization start condition preset in the control unit (not shown), for example, 3 seconds has elapsed since the power is turned on, the carriage 7 is moved to the non-recording area on the side where the stopper 72 is provided based on a signal from the control unit. The tip of the rod 78 of the piston portion 74 protruding from the carriage 7 is brought into contact with the stopper 72, and the carriage 7 is moved toward the stopper 72, and the rod 78 of the piston portion 74 is pressed by the stopper 72 and pushed inward. . Then, the piston portion 74 moves to the back side of the cylinder portion 73 while resisting the urging force of the restoring spring 76, thereby contracting the negative pressure generating chamber 75 (see FIG. 6A). At this time, the gas compressed in the negative pressure generating chamber 75 is discharged to the outside through the check valve 77 opened by the pressure increase of the negative pressure generating chamber 75 (see the white arrow in FIG. 4A).

  Next, when the carriage 7 moves away from the stopper 72, the tip of the rod 78 moves away from the stopper 72, so that the piston 74 expands the volume of the negative pressure generating chamber 75 by the restoring force of the restoring spring 76. Move (see FIG. 6B). At this time, since the check valve 77 is closed, the inside of the sealed negative pressure generating chamber 75 is depressurized due to the expansion of the volume and becomes negative pressure. Thereby, the inside of the upstream discharge empty portion 66 (downstream discharge empty portion 69) can be decompressed via the suction path 71. As described above, the decompression unit of the present embodiment can be operated by converting the driving force of the carriage 7 into the driving force of the piston pump 70 by reciprocating the carriage 7 in the non-recording area. Further, by periodically operating this decompression means, the gas in the upstream discharge empty portion 66 (downstream discharge empty portion 69) can be discharged to the outside, and the upstream discharge empty portion 66 (downstream discharge). The decompressed state in the empty portion 69) can be kept almost constant.

As described above, in the present embodiment, the pressurization mechanism 10 as the pressurizing unit pressurizes the path from the ink pack to the closed on-off valve 48, and further, the pressure in the upstream discharge empty portion 66 is reduced. A pressure difference is generated between the inside and outside of the upstream filter chamber 61 due to the reduced pressure, and the gas in the upstream filter chamber 61 passes through the permeation partition wall 65 and is discharged to the outside by this pressure difference. The discharge capacity can be further increased.
In addition, regarding the said pressure difference, it is desirable to set it more than the saturated water vapor pressure in the environmental temperature around the upstream filter chamber 61 (downstream filter chamber 62). For example, it is preferable to set this pressure difference to 10 kPa or more.

  Further, a pressure difference is generated between the downstream filter chamber 62 and the downstream discharge empty portion 69 by the pressure reduction in the downstream discharge empty portion 69 by the pressure reducing means provided on the downstream side of the on-off valve 48, and this pressure difference. As a result, the gas in the downstream filter chamber 62 passes through the permeation partition wall 68 and is discharged to the outside. Therefore, the gas is generated between the on-off valve 48 and the downstream filter chamber 62, particularly in the pressure adjustment chamber 49. The trapped bubbles can be trapped and discharged. This can more reliably prevent bubbles from entering the recording head 6 side.

  By the way, the present invention is not limited to the above embodiment, and various modifications can be made based on the description of the scope of claims.

  Regarding the pressurizing means, the above embodiment exemplifies the pressurizing mechanism 10 including the pressing plate 11 for pressing the ink pack and the biasing member 12 for biasing the pressing plate 11 toward the ink pack. This is not a limitation. Other configurations can be adopted as long as the path from the ink pack to the closed on-off valve 48 can be maintained in a pressurized state. For example, a configuration in which the ink pack is pressurized with a weight or the like instead of the pressure mechanism 10 may be employed. Further, for example, it is possible to employ a configuration that uses the water head pressure due to the vertical difference in height between the ink pack and the ink pressure adjustment unit 45 (open / close valve 48). Further, it is possible to employ a configuration in which the ink pack is pressurized by sending compressed air into the ink cartridge using a pump or the like.

  In the above embodiment, the upstream filter chamber 61 is formed on the upstream side of the open / close valve 48 in the communication flow path 47, and the upstream discharge empty portion 66 is formed outside the transmission partition wall 65 in the upstream filter 61. In addition, the configuration in which the bubbles in the upstream filter 61 are discharged to the upstream discharge empty portion 66 using the pressure difference applied by the pressurizing mechanism 10 and the pressure reducing means is illustrated, but the configuration is not limited thereto. That is, the bubbles in the ink supply path can be discharged through the inner wall surface of the supply tube 8 and the like by pressurization by the pressurizing mechanism 10, so that the decompression means is not necessarily required. For the same reason, it is not necessary to provide the upstream filter chamber 61 upstream of the on-off valve 48 in the communication channel 47.

  In the above embodiment, the downstream filter chamber 62 is formed downstream of the on-off valve 48 in the communication channel 47, and the downstream discharge empty portion 69 is formed outside the permeation partition wall 68 in the downstream filter 62. In addition, although the configuration in which the bubbles in the downstream filter 62 are discharged to the downstream discharge empty portion 69 using the pressure difference applied by the decompression means is illustrated, the present invention is not limited to this, and the downstream filter chamber 62, the downstream It is also possible to adopt a configuration in which the side discharge empty portion 69 and the pressure reducing means are not provided.

  Moreover, although the structure which converts the drive force of the carriage 7 into the drive force of the piston pump 70 and act | operates was illustrated as a pressure reduction means of this embodiment, it is not restricted to this. For example, a suction path 71 communicating with the upstream discharge empty portion 66 and the downstream discharge empty portion 69 is connected to the suction pump 40 in parallel with the discharge tube 39 (FIG. 2), and the upstream discharge empty portion 66 is connected by the suction pump 40. Alternatively, a configuration in which the downstream discharge empty portion 69 is depressurized may be employed.

  Furthermore, the present invention is not limited to the printer 1, and any display manufacturing apparatus, electrode manufacturing apparatus, or chip manufacturing can be used as long as the liquid stored in the liquid storage member is introduced into the liquid ejecting head through the liquid supply path. The present invention can also be applied to liquid ejecting apparatuses such as apparatuses and micropipettes.

FIG. 3 is a perspective view illustrating the internal configuration of the printer. 2 is a schematic diagram illustrating an internal configuration of a printer. FIG. . FIG. 3 is a cross-sectional view of a main part illustrating the configuration of a recording head. It is sectional drawing explaining the structure of an ink pressure adjustment unit. It is an expanded sectional view explaining the structure of the vicinity of an on-off valve. It is a schematic diagram explaining the structure of a pressure reduction means.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 6 ... Recording head, 7 ... Carriage, 8 ... Supply tube, 9 ... Pack storage chamber, 10 ... Pressurization mechanism, 13 ... Upstream communication port, 15 ... Downstream communication port, 45 ... Ink pressure adjustment unit , 46 ... Unit main body, 47 ... Communication flow path, 48 ... Open / close valve, 49 ... Pressure adjusting chamber, 51 ... Inlet port, 52 ... Outlet port, 53 ... Film, 61 ... Upstream filter chamber, 62 ... Downstream filter chamber , 65 ... Permeation partition wall, 66 ... Upstream discharge cavity, 68 ... Permeation partition wall, 69 ... Downstream discharge cavity, 70 ... Piston pump, 71 ... Suction path

Claims (8)

A liquid ejecting apparatus configured to supply a liquid stored in a liquid storing member to a liquid ejecting head through a liquid supply path, and to discharge the supplied liquid by the liquid ejecting head,
A pressurizing means for pumping the liquid in the liquid storage member to the liquid ejecting head side, and an on-off valve disposed in the middle of the liquid supply path for opening and closing the liquid supply path,
The pressurizing unit constantly pressurizes the liquid ejecting apparatus even when the liquid ejecting apparatus is not in operation, thereby reducing the internal pressure of the liquid supply path from the liquid storage member to the on-off valve via the liquid supply path. A liquid ejecting apparatus that maintains a pressure higher than an external pressure of the liquid ejecting apparatus.   The liquid supply member produced using the material which has gas permeability at least one part of the liquid supply path from the said liquid storage member to the said on-off valve was comprised of Claim 1 characterized by the above-mentioned. Liquid ejector. Provided upstream of the on-off valve in the liquid supply path, an upstream trap empty portion capable of capturing gas mixed in the liquid,
At least a part of the partition wall that divides the upstream trap space is allowed to permeate the gas in the upstream trap space to the outside of the upstream trap space by the pressure difference between the inside and outside of the upstream trap space by the pressurizing means. The liquid ejecting apparatus according to claim 1, wherein the permeable partition wall is possible.   4. The transmission partition wall is integrally formed using the same material as the other partition walls partitioning the upstream trap space, and is thinner than the other partition walls. The liquid ejecting apparatus according to 1.   4. The liquid ejecting apparatus according to claim 3, wherein the permeation partition wall is formed using a material having higher gas permeability than other partition walls partitioning the upstream trap space. An upstream depressurization unit that forms an upstream discharge void outside the permeation partition wall in the upstream trap void, and lowers the pressure in the upstream discharge void compared to the pressure in the upstream trap void With
Due to the pressure difference between the upstream trap empty space and the upstream discharge empty space by the pressurizing means and the upstream depressurizing means, the gas in the upstream trap empty space permeates the permeation partition wall into the upstream discharge empty space. The liquid ejecting apparatus according to claim 3, wherein the liquid ejecting apparatus is discharged. Between the on-off valve and the liquid ejecting head, a downstream trap cavity capable of capturing the gas mixed in the liquid is formed,
At least a part of the partition wall that partitions the downstream trap space, a permeation partition wall that allows gas in the downstream trap space to permeate to the outside of the downstream trap space due to a pressure difference between the inside and outside of the downstream trap space age,
Forming a downstream discharge void outside the permeation partition wall in the downstream trap void,
Downstream pressure reducing means for lowering the pressure in the downstream discharge empty portion compared to the pressure in the downstream trap empty portion,
Due to the pressure difference between the downstream trap empty space and the downstream discharge empty space by the downstream pressure reducing means, the gas in the downstream trap empty space passes through the permeation partition wall and is discharged to the downstream discharge empty space side. The liquid ejecting apparatus according to claim 1, wherein the liquid ejecting apparatus is a liquid ejecting apparatus. A carriage having a liquid jet head mounted thereon;
The liquid ejecting apparatus according to claim 1, wherein the on-off valve is provided in the carriage.

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