JP2008260267A - Pressure adjusting mechanism and liquid ejecting apparatus - Google Patents

Abstract

A pressure adjusting mechanism capable of discharging gas mixed in a pressure adjusting chamber and preventing occurrence of problems caused by the gas mixing, and a liquid ejecting apparatus including the pressure adjusting mechanism.
When a pressure in a pressure adjustment chamber is reduced below a predetermined pressure, a pressure receiving member is deformed to the inside of the pressure adjustment chamber, and the opening / closing valve is pressed against the introduction port to retreat. In the ink pressure adjustment unit 36 that converts the pressure adjustment chamber into an open valve state, a decompression empty portion 51 is formed between the pressure regulation chamber and a partition wall that divides the pressure regulation chamber. A partition wall 52 that allows gas to pass through is defined as a partition wall between the space and the pressure in the pressure-reduced space is made lower than the pressure in the pressure adjustment chamber by the operation of the pressure-reducing means. The gas in the room permeated through the permeation partition wall and was discharged to the vacuum space side.
[Selection] Figure 4

Description

  The present invention relates to a pressure adjusting mechanism applied to a liquid ejecting apparatus such as an ink jet printer, and a liquid ejecting apparatus including the pressure adjusting mechanism, and in particular, when the pressure in the pressure adjusting chamber drops below a predetermined pressure, the pressure adjusting chamber The present invention relates to a pressure adjusting mechanism having a pressure receiving member that is deformed inward, and a liquid ejecting apparatus including the pressure adjusting mechanism.

  A typical example of a liquid ejecting apparatus that includes a liquid ejecting head capable of ejecting (ejecting) liquid and ejecting various liquids from the liquid ejecting head includes, for example, recording paper as an ejection target (recording medium) An image recording apparatus such as an ink jet printer that performs recording by ejecting and landing ink droplets on the ink can be used. 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 disposed on the apparatus main body side, and a pressure adjustment mechanism for adjusting the pressure of the ink from the liquid supply source to a constant pressure is provided. There is a configuration (so-called off-carriage type) in which a supply source and a pressure adjustment mechanism are connected by a flexible liquid supply tube, and ink from the liquid supply source is supplied into the liquid ejection head via the pressure adjustment mechanism. It has been adopted (Patent Document 1).

  The pressure adjustment mechanism includes a pressure adjustment chamber that has an inlet and an outlet and stores liquid, an on-off valve that opens and closes the inlet, a biasing member that biases the on-off valve toward the inlet, A film member stretched in a state of sealing the opening surface and an operation lever attached to the film member are provided. When the internal pressure of the pressure adjusting chamber falls below a predetermined pressure, the film member is elastically deformed to the inside of the pressure adjusting chamber, and the operating lever is operated by the operating force that is doubled by the pressing force when the film member is elastically deformed. By pressing toward the valve opening position, ink flows into the pressure chamber through the inlet.

JP, 2005-186344, A

  By the way, in the above liquid ejecting apparatus, 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 with only ink. It is difficult to prevent completely. In particular, in the configuration using the above-described pressure adjustment mechanism, bubbles may be generated by external gas (air) passing through the film member and dissolving in the ink inside the pressure adjustment chamber. If the bubbles move to the recording head side, pressure fluctuations during the ejection operation may be absorbed to cause pressure loss, or problems such as insufficient ink supply due to blockage of the flow path may occur.

  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 pressure adjustment chamber and prevent the occurrence of problems caused by the gas mixing. And a liquid ejecting apparatus including the pressure adjusting mechanism.

The pressure adjusting mechanism of the present invention has been proposed to achieve the above object, and introduces and stores the liquid from the liquid supply source through the inlet and stores the stored liquid through the outlet. A pressure regulating chamber that leads to
Opening and closing disposed so as to be convertible between a valve-closed state in which introduction of liquid from the inlet to the pressure adjusting chamber is blocked and a valve-opened state in which liquid can be introduced from the inlet to the pressure adjusting chamber. A valve,
A pressure receiving member disposed in a state of sealing an opening surface on one side of the pressure adjusting chamber,
When the pressure in the pressure regulation chamber drops below a predetermined pressure, the pressure receiving member is deformed to the other side of the pressure regulation chamber, and opens by opening and closing the on-off valve that is in a closed state against the inlet. A pressure adjusting mechanism for converting into a valve state,
Forming a decompression empty space between the pressure regulation chamber and the partition wall that divides the pressure regulation chamber,
The partition wall between the pressure adjustment chamber and the decompression empty portion is a permeation partition wall through which gas can permeate. According to the pressure difference, the gas in the pressure adjustment chamber permeates the permeation partition wall and is discharged to the decompression empty space side.

  According to the above configuration, the pressure reducing chamber is formed between the pressure adjusting chamber and the partition wall that partitions the pressure adjusting chamber, and the gas is passed through the partition wall between the pressure adjusting chamber and the pressure reducing chamber. The permeation section wall is made permeable, and the pressure in the decompression space is made lower than that in the pressure regulation chamber by the operation of the decompression means, and the gas in the pressure regulation chamber permeates the permeation section wall and depressurizes due to the pressure difference. Since it is made to discharge | emit to an empty part side, the gas mixed in the pressure regulation chamber can be discharged | emitted outside. For this reason, it can suppress that a bubble grows in a pressure regulation chamber, and, thereby, the malfunction which arises because a bubble mixes in a liquid can be prevented.

  In this configuration, it is desirable that the pressure receiving member is configured by providing an airtight layer that prevents gas permeation on the flexible film.

  According to this configuration, since the intrusion of gas from the pressure receiving member can be suppressed by providing an airtight layer, coupled with the function of discharging the gas in the pressure adjustment chamber to the vacuum space, the bubbles in the liquid It becomes possible to prevent mixing more reliably.

Further, in the above configuration, a cover member that covers the entire surface of the pressure receiving member in a state where a sealing void is formed between the pressure receiving member and the pressure receiving chamber outside the pressure receiving member is provided,
It is desirable that the cover member adopt a configuration in which an air communication path that communicates the sealing void and the outside is formed.

  According to this configuration, by providing the cover member that covers the entire surface of the pressure receiving member, it is possible to increase the humidity in the sealed void. Thereby, it becomes possible to suppress the partial pressure difference between the sealed empty space and the pressure adjusting chamber, and it is possible to suppress the intrusion of gas from the pressure receiving member. As a result, it becomes possible to contribute to prevention of mixing of bubbles in the liquid. Moreover, since the sealing empty part is open | released by air | atmosphere, it can suppress that the trouble of the displacement of a pressure receiving member comes.

  In each of the above-described configurations, the pressure adjustment chamber and the decompression empty portion are configured such that the gas transmission speed in the permeation partition wall is higher than the inflow speed of the gas that passes through the pressure receiving member and flows into the pressure adjustment chamber. It is desirable to adopt a configuration that sets the pressure difference. In this configuration, it is desirable that the pressure difference between the pressure regulation chamber and the decompression cavity is set to be equal to or higher than the saturated water vapor pressure at the ambient temperature around the pressure regulation chamber.

  According to this configuration, the gas growth rate in the pressure adjustment chamber is increased by making the gas permeation rate in the permeation partition wall higher than the inflow rate of the gas that permeates the pressure receiving member and flows into the pressure adjustment chamber. It can suppress more reliably.

In each of the above-described configurations, it is desirable that the transmission partition wall is formed of a rigid wall having rigidity capable of retaining a shape even when subjected to a pressure change by at least the pressure reducing means.
In this configuration, it is preferable that the permeation partition wall is constituted by a part of a structure that forms the liquid flow path.

  According to this configuration, since the permeation partition wall is a rigid wall, it is possible to suppress deformation and breakage of the permeation partition wall and bleeding of liquid when a pressure difference is generated by the decompression means. Further, it is possible to prevent the pressure adjustment mechanism from malfunctioning by preventing the pressure fluctuation in the pressure adjustment chamber due to the bending of the permeation partition wall according to the pressure fluctuation caused by the pressure reducing means.

  In the above configuration, the permeation partition wall is integrally formed using the same material as the structure forming the pressure adjustment mechanism, and the portion of the partition wall of the structure forming the pressure adjustment mechanism is in contact with the outside air It is possible to adopt a configuration that is thinner than that.

  According to this configuration, since the permeable partition wall is integrally formed using the same material as the structure forming the pressure adjusting mechanism, the step of separately molding and attaching the permeable partition wall can be omitted, and the gas Permeability can be increased.

  Further, in the above configuration, the structure including the permeation partition wall is made of a material different from other structures forming the pressure adjusting mechanism and using a material having higher gas permeability than the other structures. The structure to form can also be employ | adopted.

  According to this configuration, gas permeability can be ensured for the permeation partition wall, and airtightness can be further ensured in other portions. This makes it possible to more efficiently remove the gas in the pressure adjustment chamber.

Moreover, the liquid ejecting apparatus of the present invention includes the pressure adjusting mechanism having the above-described configuration,
The liquid stored in the liquid storage member as the liquid supply source is introduced into the pressure adjustment mechanism through the liquid supply path, the pressure is adjusted by the pressure adjustment mechanism, and then supplied to the liquid ejecting head side and supplied. The liquid ejecting head is configured to eject liquid.

  According to this configuration, since there is little possibility of bubbles flowing into the flow path of the head from the pressure adjustment mechanism side, it is possible to prevent problems such as pressure loss and insufficient supply of liquid due to the bubbles.

Further, in the above configuration, a gas trap cavity for capturing bubbles in the liquid supply path is formed in the middle of the liquid supply path from the liquid storage member to the inlet of the pressure adjustment mechanism,
A part of the partition wall that defines the gas trap space is a transmission partition wall,
Forming a gas recovery cavity outside the gas trap cavity through the permeation partition wall,
By operating the pressure reducing means, the pressure in the gas recovery space is made lower than the pressure in the gas trap space, so that the gas in the gas trap space passes through the permeation partition wall to the gas recovery space side. It is desirable to adopt a structure for discharging.

  According to this configuration, it is possible to suppress the generation of bubbles on the upstream side of the pressure adjustment mechanism, so it is possible to more reliably prevent problems such as pressure loss and insufficient liquid supply caused by the bubbles. .

  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. In the paper feed tray 3 and the paper discharge tray 4, recording paper as a print target (discharge target or jet target) is set in the paper feed tray 3. The recording paper set in the paper feed tray 3 is sent out to the platen 14 side inside the printer 1 by a paper feed mechanism (not shown). 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. The guide rod 5 is supported by a carriage 7 on which a recording head 6 and an ink pressure adjusting unit 36 (corresponding to the pressure adjusting mechanism of the present invention), which will be described later, are mounted. 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 drive force is transmitted through the drive belt, and the carriage 7 reciprocates in the direction along the guide rod 5, that is, in the main scanning direction.

  On the other hand, the recording head 6 as a liquid ejecting head attached to the lower surface of the carriage 7 (the surface facing the platen 14) has a nozzle forming surface (nozzle forming substrate 28; see FIG. 3) so as to face the recording paper. A plurality of nozzle rows (for example, six rows) formed by arranging a plurality of nozzle openings are formed on the nozzle forming surface. The recording head 6 has a color corresponding to each nozzle row from the first and second ink cartridges 8a and 8b as liquid supply sources or liquid storage members provided in the casing 2, as will be described later. In this embodiment, ink is supplied as liquid (black, cyan, magenta, yellow, light cyan, and light magenta). The ink flowing into the recording head 6 is pressurized by the operation of the piezoelectric element 24 (see FIG. 3), and is ejected (ejected) as an ink droplet from the nozzle opening of the recording head 6 to form dots. That is, the corresponding colors, black, cyan, magenta, yellow, light cyan, and light magenta, are ejected from the nozzle openings of the nozzle rows formed in the recording head 6.

  In the printer 1, an area for printing by landing ink on a recording sheet while reciprocating the carriage 7 is set as a printing area. Further, the printer 1 is provided with a home position in which the carriage 7 is arranged in a printing pause state in an area outside the printing area (on the right front side in FIG. 1). A capping mechanism 9 is provided at this home position. The capping mechanism 9 includes a cap holder 10 (FIG. 2) that can be moved up and down by a lifting mechanism (not shown). The cap holder 10 is provided with a cap member 11 as a sealing means. The cap member 11 is a tray-like member having an open upper surface, and is made of an elastic member such as an elastomer, for example.

  An absorbing material made of a porous material for absorbing ink or the like is laid inside the cap member 11. Further, through holes 12 a and 12 b are formed on the bottom surface of the cap member 11. An air release valve 13 is connected to the through hole 12b via a tube T1. The air release valve 13 can open the sealing space formed by bringing the cap member 11 and the nozzle formation surface into close contact with each other. Furthermore, the through hole 12a is connected to the pump unit 14 via the tube T2. The pump unit 14 includes a tube pump that sends fluid by handling the tube with a roller or the like, a gear pump that sends fluid downstream by rotating a drive gear and a driven gear, and the like. Air bubbles are sucked and discharged. That is, when the nozzle forming surface is sealed by the cap member 11, by driving the pump unit 14, negative pressure is applied to the nozzle opening on the nozzle forming surface, and ink or bubbles are forced from the nozzle opening. Cleaning for discharging (gas) can be performed.

  An adjusting device 15 is connected to the downstream side of the pump unit 14 via a tube T3, and the first ink cartridge 8a is connected to the adjusting device 15 via a tube T4. The first ink cartridge 8a accommodates an ink pack B that stores black ink and an ink absorber 17 that absorbs ink. The ink pack B is connected to the carriage 7 side through a tube T5. The ink absorber 17 is made of, for example, a porous material having water absorption properties such as sponge.

  With this configuration, waste ink or gas sucked from the cap member 11 by the pump unit 14 flows into the first ink cartridge 8a. At this time, the waste ink that has flowed into the first ink cartridge 8 a is absorbed by the ink absorber 17. Further, the amount of waste ink and gas flowing into the first ink cartridge 8 a and the flow velocity thereof are adjusted by the adjusting device 15.

  A second ink cartridge 8b is connected to the first ink cartridge 8a via a tube T6 and communicates with each other. The second ink cartridge 8b includes ink packs C, M, Y, LC, and LM for storing cyan, magenta, yellow, light cyan, and light magenta inks, respectively. The ink packs C, M, Y, LC, and LM are connected to the carriage 7 via tubes T7 to T11, respectively. The second ink cartridge 8b is connected to an atmosphere release device 18 for releasing the inside of the second ink cartridge 8b through the tube T12.

  When the pump unit 14 is driven, waste ink and gas are sucked from the cap member 11, and the waste ink and gas are collected from the cap member 11, the tube T2, the pump unit 14, the tube T3, the adjusting device 15, and the tube T4. And then flow into the ink cartridge 8a. At this time, the waste ink that flows into the first ink cartridge 8a is absorbed by the ink absorber 17 described above, and thus flows into the first ink cartridge 8a only by the gas that flows in (pressurized air). . The pressurized air flows from the first ink cartridge 8a into the second ink cartridge 8b via the tube T6, and then moves to the atmosphere release device 18 connected to the tube T12. Yes.

  That is, when the pump unit 14 is operated, the internal pressures of the first and second ink cartridges 8a and 8b are pressurized by the above-described pressurized air, and the respective ink packs B, C, M, Y, LC, and LM. Is to be pressurized. As a result, the ink stored in the ink packs B, C, M, Y, LC, and LM is pressure-fed to the recording head 6 side of the carriage 7, respectively.

  In other words, in the printer 1 of the present embodiment, the pump unit 14 applies the cleaning pump that applies a negative pressure to the sealing empty portion of the cap member 11 and the ink packs B, C, M, Y, LC, and LM. It also serves as a pressurizing pump to press. When the pump unit 14 is driven, a negative pressure is applied to the cap member 11 to suck the waste ink and air, and the ink packs B, C, M, Y, LC, and LM are pressurized to the recording head 6 side. Each ink is pumped.

  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 34 of an ink pressure adjustment unit 36, which will be 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 elements 24 (a kind of pressure generating means) arranged in a comb shape, a wiring member (not shown) for supplying a drive signal to the piezoelectric elements 24, and a piezoelectric element. It comprises a fixed substrate 25 and the like for fixing the element 24. The piezoelectric element 24 is joined to a diaphragm portion (diaphragm) that partitions the pressure chamber 26 in the flow path unit 22. The piezoelectric element 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. Ink droplets can be ejected from the opening 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 36 side of the carriage 7 through the common ink chamber 30.

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

Next, the ink pressure adjustment unit 36 mounted on the carriage 7 will be described.
FIG. 4 is a cross-sectional view of the ink pressure adjustment unit 36 in the present embodiment, and FIG. 5 is a plan view of the ink pressure adjustment unit 36. The ink pressure adjusting unit 36 introduces and stores the ink sent from the ink cartridge 8 through the upstream communication port 33 and the introduction port 37 and records the stored liquid through the outlet port 38 and the downstream communication port 34. A pressure adjustment chamber 39 led out to the head 6 (corresponding to a liquid supply object in the present invention), a closed state in which the introduction of ink from the introduction port 37 to the pressure adjustment chamber 39 is blocked, and the pressure adjustment chamber 39 from the introduction port 37. An on-off valve 40 arranged to be convertible into a valve-opening state that allows ink to be introduced into the ink, and a pressure-receiving member 41 arranged to seal the opening surface on one side of the pressure adjusting chamber 39 The unit main body 43 is configured to include a pressure adjusting unit 45. The pressure adjusting unit 45 is provided corresponding to each color ink. In this embodiment, as shown in FIG. 5, a total of six pressure adjusting units 45 a to 45 e are formed side by side in the unit main body 43. . The unit main body 43 is made of a synthetic resin.

  The pressure adjustment chamber 39 is configured by a rectangular depression that is long in a direction orthogonal to the direction in which the pressure adjustment sections 45 are arranged. In this embodiment, the depth of the depression is relative to the thickness of the unit main body 43. It is about 1/3. Further, an introduction port 37 is opened at the bottom of one end side (left side in FIG. 4) of the pressure adjusting chamber 39, and an outlet port 38 is opened at the bottom of the other end side (right side in FIG. 4). .

The pressure receiving member 41 is a flexible film member 42 that elastically deforms to the inside (downward in FIG. 1) of the pressure adjusting chamber 39 when the internal pressure of the pressure adjusting chamber 39 becomes lower than a predetermined pressure (when it reaches a predetermined negative pressure). And an operating lever 44 provided on the inner side (pressure adjusting chamber side) of the film member 42. The film member 42 has a configuration in which silica (SiO ₂ ) is vapor-deposited as an airtight layer on the surface of a flexible film formed by laminating a polyethylene terephthalate film and a polypropylene film, for example. That is, by providing this airtight layer, the airtight layer prevents the gas from passing through the film member 42. The film member 42 is bonded or welded to the surface of the unit main body 43 so as to seal the opening of the recess that becomes the pressure adjusting chamber 39 (that is, the opening surface on one side of the pressure adjusting chamber 39). Accordingly, the film member 42 defines a part of the pressure adjustment chamber 39.

  The actuating lever 44 is provided in a so-called cantilever state in which the one end 44 a side is supported by the unit main body 43 in the pressure adjusting chamber 39. The on-off valve 40 is disposed so as to receive an operating force from the operating lever 44 at a position closer to one end side than the center of gravity of the operating lever 44. The operating lever 44 is made of a metal plate such as stainless steel.

  The on-off valve 40 can be converted between an open state that allows ink to be introduced into the pressure adjustment chamber 39 and a closed state (state shown in FIG. 1) that blocks the introduction of ink into the pressure adjustment chamber 39. And is disposed in a storage chamber 47 formed on the upstream side of the introduction port 37 in a state of being biased toward the valve closing position by a biasing member 46 formed of a deformed coil spring. The on-off valve 40 includes a columnar shaft portion 48, a substantially disc-shaped flange portion 49 extending laterally from the middle of the longitudinal direction of the shaft portion 48, and the upper surface side (the pressure adjustment chamber 39 side) of the flange portion 49. ) And the packing 50 arranged. The distal end portion of the shaft portion 48 (the distal end side with respect to the flange portion 49) is formed so that the outer diameter thereof is smaller than the inner diameter of the introduction port 37, and is inserted into the pressure adjustment chamber 39 through the introduction port 37. The ink from the upstream communication port 33 side is introduced into the pressure adjustment chamber 39 through a gap between the shaft portion 48 and the inner peripheral surface of the introduction port 37. The packing 50 is formed in a so-called O-ring shape by an elastic member such as an elastomer, for example.

  The urging member 46 abuts on the flange portion 49 of the on-off valve 40 to urge the on-off valve 40 toward the pressure adjustment chamber 39 and keep the closed state until the pressure adjustment chamber 39 is depressurized to a predetermined pressure. It has become. That is, the opening / closing valve 40 urged to the ceiling surface side of the storage chamber 47 by the urging member 46 has the packing 50 connected to the opening peripheral portion of the introduction port 37 as long as it does not receive stress against the elastic force of the urging member 46. Is held in the valve-closed position in close contact with. In the closed position, the on-off valve 40 blocks the inflow of ink into the pressure adjustment chamber 39.

  When the inflow of ink into the pressure adjustment chamber 39 is blocked by the on-off valve 40, the internal pressure of the pressure adjustment chamber 39 gradually decreases due to ink consumption by the recording head 6. When the pressure adjustment chamber 39 is depressurized to a predetermined pressure (the minimum pressure at which the recording head 6 does not interfere with ink ejection), the pressure receiving member 41 is elastically deformed to the inside (the other side) of the pressure adjustment chamber 39. Then, the operating lever 44 is pressed downward. As a result, the operating lever 44 presses the distal end portion of the shaft portion 48 of the on-off valve 40 at the valve closing position by the operating force that is a boost of the pressing force when the pressure receiving member 41 is elastically deformed, and the biasing member 46. The on-off valve 40 is moved in the opening direction while resisting the elastic force. Thereby, the opening / closing valve 40 is displaced to a position (opening position) where the packing 50 is separated from the opening peripheral edge of the introduction port 37 and the contact state is released. In this valve opening position, ink is allowed to flow into the pressure adjusting chamber 39 through the introduction port 37. When ink is introduced into the pressure adjustment chamber 39, the internal pressure of the pressure adjustment chamber 39 is increased from the minimum pressure. When the internal pressure of the pressure adjustment chamber 39 is increased, the film member 42 is displaced toward the upper side (one side) of the pressure adjustment chamber 39. As a result, the on-off valve 40 moves back due to the elastic force of the urging member 46, and is again displaced to the valve closing position to block the inflow of ink into the pressure adjusting chamber 39.

  In this way, the ink pressure adjustment unit 36 adjusts the pressure of the ink supplied to the recording head 6 to a constant pressure by the reciprocating movement between the valve closing position and the valve opening position of the opening / closing valve 40, and Avoid excessive pressure boosting that results in ejection failure.

  By the way, in the ink pressure adjustment unit 36 having the above-described configuration, bubbles may be generated when an external gas (air) passes through the film member 42 and is mixed into the ink inside the pressure adjustment chamber 39. If the bubbles move to the recording head 6 side, pressure fluctuations during the ejection operation may be absorbed, causing pressure loss, or causing problems such as insufficient ink supply due to the ink flow path being blocked. . For this reason, the ink pressure adjusting unit 36 is provided with a cover member 53 that covers the entire pressure receiving member of each pressure adjusting unit 45 on the outer side of the pressure receiving member 41 of the pressure adjusting chamber 39.

  FIG. 6 is a plan view of the cover member 53 as viewed from the opening surface side. The cover member 53 is a tray-like member that is formed in a rectangular shape in plan view in accordance with the planar shape of the ink pressure adjusting unit 36 and has an opening on the surface facing the pressure receiving member 41. In this embodiment, as shown in FIG. 4, it has a double structure in which a main body 53a and a sealing member 53b are laminated, and the groove-like flow path formed in the sealing member 53 is used as a sealing member. By sealing with 53b, the atmosphere communication path 55 is formed inside. The cover member 53 is joined to the unit main body 43 in a state where a sealing void 54 is formed between the cover member 53 and the pressure receiving member 41.

  The sealing empty portion 54 is a space that is set to such a size that the cover member 53 does not interfere with the pressure receiving member 41 when the pressure receiving member 41 side is displaced to the maximum in the direction away from the pressure adjustment chamber 39. It communicates with the atmosphere via the atmosphere communication path 55. The atmospheric communication passage 55 is a flow path that communicates between the inner opening 56 that opens to the sealing empty portion 54 side and the outer opening 57 that opens to the outer surface of the cover member 53, as shown by a broken line in FIG. 6. In this way, the overall length of the passage is made as long as possible. In this way, by setting the overall length of the atmosphere communication path 55 as long as possible, the sealing void 54 is opened to the atmosphere and the displacement of the pressure receiving member 41 is allowed. Escape to the outside through the communication path 55 can be suppressed.

  Then, by providing the cover member 53 having the above-described configuration in the ink pressure adjusting unit 36, the humidity in the sealing empty portion 54 can be increased as much as possible (a state close to water vapor saturation). Thereby, it is possible to suppress a partial pressure difference between the sealed empty portion 54 and the pressure adjusting chamber 39, and gas intrusion from the pressure receiving member 41 can be suppressed. As a result, it becomes possible to contribute to preventing bubbles from being mixed into the ink.

  4 and 5, the ink pressure adjusting unit 36 forms a decompression empty part 51 in the vicinity of the bottom of the pressure adjustment chamber 39, and the decompression empty part 51 is filled with decompression means (pressure) (described later). The pressure is made lower than the pressure in the pressure adjusting chamber 39 by the difference applying means), and the gas (bubbles) in the pressure adjusting chamber 39 is made into a partition wall between the decompression empty space 51 and the pressure adjusting chamber 39 by this pressure difference. And is discharged to the decompression empty space 51 side.

  The decompression cavity 51 is a rectangular parallelepiped cavity elongated in the direction in which the pressure regulators 45 are arranged, and is formed across the pressure regulators 45a to 45e as indicated by broken lines in FIG. . The decompression empty space 51 is formed between the pressure adjustment chamber 39 and a partition wall that partitions the pressure adjustment chamber 39. The partition wall between the decompression empty space 51 and the pressure adjustment chamber 39 is thinner than other partition walls partitioning the pressure adjustment chamber 39, and functions as a permeable partition wall 52 through which gas can permeate. To do. That is, the transmission partition wall 52 is constituted by a part of a unit main body 43 that is a structure that forms the ink pressure adjusting unit 36, and is integrally formed using the same material as the unit main body 43. It is thinner than the part which contacts outside air among 43 partition walls. Thereby, the process which shape | molds and attaches the permeation | separation division wall 52 separately from the unit main body 43 can be skipped, and also the gas permeability can be improved rather than other division walls.

  The permeation partition wall 52 exchanges gas due to a pressure difference between the pressure adjustment chamber 39 and the decompression cavity 51 while ensuring rigidity that can retain its shape even when subjected to a pressure change in the pressure adjustment chamber 39. In other words, it is desirable to make the wall rigid enough to allow gas permeation. For example, the material of the unit main body 43 including the transmission partition wall 52 is a plastic such as POM (polyacetal), m-PPE (modified polyphenylene ether), PP (polypropylene), or an alloy thereof, and the thickness of the transmission partition wall 52 is It is preferable to set the thickness to about 10% to 50% of the average thickness of other portions, and generally set to about 0.5 mm.

  Then, the pressure reducing chamber 51 is made to have a lower pressure than the pressure in the pressure adjusting chamber 39 by the pressure reducing means, and the gas (bubbles) in the pressure adjusting chamber 39 is transmitted through the transmission partition wall 52 by this pressure difference. It discharges to the decompression empty part 51 side. FIG. 7 is a schematic diagram for explaining a configuration in which the decompression empty portion 51 is decompressed by decompression means. As shown in the figure, a cleaning pump unit 14 is used as the decompression means in the present embodiment. Specifically, the suction path 59 leading to the decompression empty part 51 is connected to the pump unit 14 in parallel with the tube T2 for decompressing the inside of the cap member 11 (see FIG. 2). A configuration in which the inside of the empty portion 51 is decompressed is adopted. The suction path 59 is connected to the discharge port 61 of the decompression empty portion 51 via a check valve 60 that allows ventilation from the decompression empty portion 51 to the pump unit 14 and prevents the reverse.

  When the pump unit 14 is operated in the above configuration, the inside of the decompression empty portion 51 can be decompressed via the suction path 59. Thereby, the pressure in the decompression empty part 51 can be made low compared with the pressure in the pressure regulation chamber 39. Due to this pressure difference, the gas (bubbles) in the pressure adjustment chamber 39 can be discharged to the decompression empty space 51 side through the permeation partition wall 52. Thus, even if a gas is mixed into the ink in the pressure adjusting chamber 39 through the pressure receiving member 41, the gas can be discharged to the outside. For this reason, it is possible to suppress the growth of bubbles in the pressure adjusting chamber 39, and it is possible to prevent problems caused by the bubbles being mixed into the recording head 6 side. As a result, the execution frequency of the cleaning operation for discharging bubbles can be reduced as compared with the conventional case, so that consumption of ink accompanying the cleaning operation can be reduced.

  Further, in the above configuration, the magnitude of the negative pressure applied to the decompression empty space 51 is easily adjusted by setting the pressure threshold value for opening the check valve 60, setting the suction time of the pump unit 14, and the like. It is possible. That is, a control unit (not shown) of the printer 1 can appropriately set a pressure difference between the reduced pressure empty portion 51 and the pressure adjusting chamber 39 by adjusting the pressure in the reduced pressure empty portion 51. . It is desirable to set the pressure difference so that the gas permeation speed in the permeation partition wall 52 is higher than the inflow speed of the gas that permeates the pressure receiving member 41 and flows into the pressure adjusting chamber 39. In the present embodiment, it is desirable to set this pressure difference to be equal to or higher than the saturated water vapor pressure at the ambient temperature around the pressure adjustment chamber 39. Specifically, for example, it is preferable to set the pressure difference to 5 kPa or more and 30 kPa or less at room temperature (25 ° C.). By setting the pressure difference in this way, gas growth in the pressure adjustment chamber 39 can be effectively suppressed. Even if the pressure difference is set to 5 kPa or less, the same effect can be obtained if the pressure difference is kept for a long time, so that the pressure difference should be larger than 0 kPa.

  Here, by merely giving a pressure difference between the decompression empty part 51 and the pressure adjusting chamber 39, the growth of bubbles may depend on the limitation of the volume of the space that can be secured as the decompression empty part 51 and the decompression ability of the decompression means. There are cases where it is difficult to reliably suppress this. However, in the present embodiment, since the above-described cover member 53 is used to increase the humidity in the sealing void 54 (outside of the pressure receiving member 41) as much as possible, the pressure is received through the pressure receiving member 41. The gas can be prevented from entering the adjustment chamber 39. Similarly, in the present embodiment, an airtight layer is provided on the pressure receiving member 41, and the gas is prevented from passing through the film member 42 by the airtight layer. For this reason, even when there is a restriction as described above, the effect of suppressing bubble growth can be further enhanced by these synergistic effects.

  Since the rigidity is increased as compared with the configuration in which the permeation partition wall 52 is a rigid wall and a gas permeable film such as silicon is used as the permeation partition wall, a pressure difference is generated by a pressure difference applying means such as a decompression means. In this case, deformation or breakage of the transmission partition wall, ink bleeding on the transmission partition wall, and the like can be suppressed. Further, it is possible to prevent the ink pressure adjusting unit 36 from malfunctioning by preventing the pressure fluctuation in the pressure adjusting chamber 39 due to the bending of the transmission partition wall 52 in accordance with the pressure fluctuation by the pressure difference applying means.

  By the way, the above-described configuration is mainly for suppressing the growth of gas entering through the pressure receiving member 41. Therefore, in order to further secure the bubble suppression effect, the ink pressure adjustment unit 36 is more reliable. It is important to prevent the generation of bubbles on the upstream side as much as possible. Therefore, in the printer 1, a gas trap space capable of capturing bubbles in the liquid supply path in the middle of the liquid supply path from the ink cartridge 8 to the inlet 37 of the ink pressure adjustment unit 36 through the supply tube. A part of the partition wall forming the part 64 and partitioning the gas trap space 64 is defined as a transmission partition wall 65, and the gas is recovered outside the gas trap space 64 via the transmission partition wall 65. The empty portion 67 is formed, and the pressure in the gas recovery empty portion 67 is made lower than the pressure in the gas trap empty portion 64 by the operation of the decompression means, thereby allowing the gas in the gas trap empty portion 64 to pass through. The gas passes through the partition wall 65 and is discharged to the gas recovery empty portion side.

  In the present embodiment, as shown in FIG. 7, a trap portion 66 is provided in the vicinity of the ink pressure adjustment unit 36. The trap portion 66 may be configured separately from the ink pressure adjustment unit 36 or may be configured integrally with the ink pressure adjustment unit 36 (unit main body 43). Inside the trap portion 66, there is formed a communication channel 68 that communicates the tube communicating with each ink cartridge and the upstream communication port 33 of the ink pressure adjusting unit 36. A trap empty portion 64 is formed. The gas trap empty portion 64 has a diameter larger than that of the other portion of the communication channel 68, and a filter 69 is disposed therein.

  The filter 69 is a member for filtering ink in the communication flow path 68 (liquid supply path), and is formed by, for example, finely braiding metal into a mesh shape. The filter 69 in the present embodiment also has a function of trapping in the gas trap space 64 by making it difficult for air bubbles mixed in the liquid supply path to pass therethrough. Since the gas trap empty portion 64 of the present embodiment is formed by enlarging the inner diameter of the communication flow path 68 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 filter 69, so that the bubbles flowing in from the upstream side can be captured in the upper part of the filter 69.

  Then, a part of the partition walls defining the gas trap space 64 is made thinner than the other partition walls (parts in contact with the outside air), and this thin part is used as the transmission partition wall 65, and this transmission partition wall A gas recovery cavity 67 is formed on the outer periphery of the gas trap cavity 64 with a gap 65 therebetween. The permeation partition wall 65 is formed of a part of the structure forming the trap portion 66, and is configured as a rigid wall having rigidity capable of maintaining a shape even when subjected to pressure change by at least the pressure reducing means (pump unit 14). . The permeation partition wall 65 is provided to allow the gas trapped in the gas trap cavity 64 to escape to the outside (gas recovery cavity 67 side). In addition, the gas recovery empty portion 67 is configured to communicate with the pump unit 14 through a suction path 70 connected via a check valve 71. Then, the gas (bubbles) trapped in the gas trap space 64 due to the pressure difference between the gas trap space 64 and the gas recovery space 67 by the decompression means is transmitted through the transmission partition wall 65 to the gas recovery space 67. It is trying to discharge. Thereby, bubbles generated in the liquid supply path can be trapped and discharged.

  In addition, as a method of providing the pressure difference between the gas trap empty portion 64 and the gas recovery empty portion 67, not only the pressure reduction but also a method by pressurization can be adopted. In this case, it is desirable to provide an open / close valve for opening and closing the communication channel 68 on the downstream side of the gas trap empty portion 64 in the communication channel 68.

  In this way, the gas trap empty portion 64 is formed in the middle of the liquid supply path from the ink cartridge through the supply tube to the introduction port 37 of the ink pressure adjustment unit 36, and bubbles upstream from the ink pressure adjustment unit 36 are formed. By suppressing the occurrence of this, it is possible to further ensure the bubble suppression effect in the ink pressure adjustment unit 36, and to more reliably prevent the problems caused by the bubbles.

  Since the printer 1 includes the ink pressure adjustment unit 36 having the above-described configuration, there is little possibility that bubbles will flow into the flow path of the recording head 6 from the ink pressure adjustment unit 36 side. And problems such as insufficient ink supply can be prevented.

  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.

  In the above embodiment, the example in which the transmission partition wall 52 is integrally formed using the same material as that of the unit main body 43 that is a structure that forms the ink pressure adjustment unit 36 has been described. . For example, as in the second embodiment shown in FIG. 8, the structure including the permeable partition wall 52 is separated from the other structure forming the unit main body 43, and the gas transmission is higher than that of the other structure. It is also possible to use a material having high properties.

  In the second embodiment, the unit main body 43 has a three-layer structure in which a first structure 43a, a second structure 43b, and a third structure 43c are stacked. The material of the second structure 43b including the permeable partition wall 52 is formed using a material having higher gas permeability than the materials of the other structures 43a and 43c. Specifically, plastics such as m-PPE (modified polyphenylene ether) or PP (polypropylene) or alloys thereof can be used. On the other hand, the other structures 43a and 43c are made of a material having low gas permeability, such as PPS (polyphenylene sulfide), m-PPE / PPS alloy (alloy of modified polyphenylene ether and polyphenylene sulfide), liquid crystal polymer, EVOH (ethylene- It is desirable to use a vinyl alcohol copolymer resin). Thereby, about the permeation | separation partition wall 52, while ensuring gas permeability, airtightness can be made more reliable in another part. As a result, the gas in the pressure regulation chamber 39 can be removed more efficiently.

  Moreover, in each said embodiment, although the structure using the pump unit 14 for cleaning was illustrated as a pressure reduction means, it is not restricted to this. That is, it is possible to provide a dedicated pump or the like for decompressing the decompression empty portion 51. In addition, as long as a pressure difference can be applied between the decompression empty space 51 and the pressure regulation chamber 39, various decompression means can be used.

  In addition, 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 via 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 a top view explaining the structure of an ink pressure adjustment unit. It is a top view explaining the structure of a cover member. It is a schematic diagram explaining the structure which decompresses a decompression empty part by a decompression means. It is sectional drawing explaining the structure of the ink pressure adjustment unit in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer, 6 ... Recording head, 7 ... Carriage, 8 ... Ink cartridge, 14 ... Pump unit, 33 ... Upstream communication port, 34 ... Downstream communication port, 36 ... Ink pressure adjustment unit, 37 ... Inlet port, 38 DESCRIPTION OF SYMBOLS ... Lead-out port, 39 ... Pressure adjustment chamber, 40 ... Open / close valve, 41 ... Pressure receiving member, 42 ... Film member, 43 ... Unit main body, 44 ... Actuation lever, 45 ... Pressure adjustment part, 51 ... Pressure reduction empty part, 52 ... Transmission Partition wall, 53 ... cover member, 59 ... suction path

Claims (11)

A pressure adjusting chamber for introducing and storing the liquid from the liquid supply source through the inlet, and leading the stored liquid to the liquid supply target side through the outlet;
Opening and closing disposed so as to be convertible between a valve-closed state in which introduction of liquid from the inlet to the pressure adjusting chamber is blocked and a valve-opened state in which liquid can be introduced from the inlet to the pressure adjusting chamber. A valve,
A pressure receiving member disposed in a state of sealing an opening surface on one side of the pressure adjusting chamber,
When the pressure in the pressure regulation chamber drops below a predetermined pressure, the pressure receiving member is deformed to the other side of the pressure regulation chamber, and opens by opening and closing the on-off valve that is in a closed state against the inlet. A pressure adjusting mechanism for converting into a valve state,
Forming a decompression empty space between the pressure regulation chamber and the partition wall that divides the pressure regulation chamber,
The partition wall between the pressure adjustment chamber and the decompression empty portion is a permeation partition wall through which gas can permeate. A pressure adjusting mechanism characterized in that the gas in the pressure adjusting chamber permeates through the permeation partition wall and is discharged to the decompression empty portion side by the pressure difference.   The pressure adjusting mechanism according to claim 1, wherein the pressure receiving member is configured by providing a flexible film with an airtight layer that prevents permeation of gas. A cover member that covers the entire surface of the pressure receiving member in a state in which a sealing void is formed between the pressure receiving member and the pressure receiving member is provided outside the pressure adjusting chamber.
The pressure adjusting mechanism according to claim 1, wherein the cover member is formed with an air communication path that communicates the sealing empty portion with the outside.   The pressure difference between the pressure adjustment chamber and the decompression space is set so that the gas transmission speed in the permeation partition wall is higher than the inflow speed of the gas that passes through the pressure receiving member and flows into the pressure adjustment chamber. The pressure adjustment mechanism according to any one of claims 1 to 3, wherein the pressure adjustment mechanism is provided.   5. The pressure adjustment mechanism according to claim 4, wherein a pressure difference between the pressure adjustment chamber and the decompression empty space is set to be equal to or higher than a saturated water vapor pressure at an environmental temperature around the pressure adjustment chamber.   6. The liquid according to claim 1, wherein the permeation partition wall is formed of a rigid wall having rigidity capable of retaining a shape even when subjected to a pressure change by the decompression unit. Injection device.   The liquid ejecting apparatus according to claim 6, wherein the transmission partition wall is configured by a part of a structure that forms a pressure adjustment mechanism.   The transmission partition wall is integrally formed using the same material as the structure forming the pressure adjustment mechanism, and is made thinner than the portion of the partition wall of the structure forming the pressure adjustment mechanism that is in contact with the outside air. The liquid ejecting apparatus according to claim 7.   The structure including the permeation partition wall is formed of a material that is different from other structures forming the pressure adjustment mechanism and has a higher gas permeability than the other structures. The liquid ejecting apparatus according to claim 7. A pressure adjustment mechanism according to any one of claims 1 to 9, comprising:
The liquid stored in the liquid storage member as the liquid supply source is introduced into the pressure adjustment mechanism through the liquid supply path, the pressure is adjusted by the pressure adjustment mechanism, and then supplied to the liquid ejecting head side and supplied. A liquid ejecting apparatus configured to eject liquid by a liquid ejecting head. In the middle of the liquid supply path from the inside of the liquid storage member to the inlet of the pressure adjustment mechanism, a gas trap cavity for capturing bubbles in the liquid supply path is formed,
A part of the partition wall that defines the gas trap space is a transmission partition wall,
Forming a gas recovery cavity outside the gas trap cavity through the permeation partition wall,
By operating the pressure reducing means, the pressure in the gas recovery space is made lower than the pressure in the gas trap space, so that the gas in the gas trap space passes through the permeation partition wall to the gas recovery space side. The liquid ejecting apparatus according to claim 10, wherein the liquid ejecting apparatus is discharged.

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