JP4529607B2 - Liquid ejecting apparatus cleaning method and liquid ejecting apparatus - Google Patents

Description

  The present invention relates to a cleaning method for a liquid ejecting apparatus and a liquid ejecting apparatus.

  As a liquid ejecting apparatus that ejects liquid from a liquid ejecting head to a target, for example, an ink jet recording apparatus (hereinafter simply referred to as a printer) is known. This printer includes a cartridge for containing ink, and a recording head mounted on a carriage and supplied with ink from the cartridge. Among such printers, a so-called off-carriage is provided in which a cartridge is disposed in a place other than the carriage for the purpose of downsizing and reducing the load on the carriage, and the ink of the cartridge is supplied to the recording head via a supply channel. There is an expression printer. Since this printer has a large relative distance between the cartridge and the recording head, for example, the printer includes an ink supply mechanism that pressurizes the ink in the cartridge with pressurized air that is pumped from a pressurizing pump and pumps the ink toward the recording head. Yes. As this pressurizing pump, a positive displacement pump such as a diaphragm pump that alternately repeats an exhaust operation for compressing an air chamber and an intake operation for expanding the air chamber is used from the viewpoint of prevention of an increase in size and pump efficiency (for example, , See Patent Document 1).

  A maintenance mechanism is usually provided in a non-printing area in the printer. This maintenance mechanism includes a suction pump and the like, and performs cleaning for sucking ink, bubbles, and the like thickened from the nozzles in order to prevent nozzle clogging and the like of the recording head.

  Some printers are each provided with a plurality of valve mechanisms for performing choke cleaning in the middle of each supply channel provided between the cartridge and the recording head. In the choke cleaning, the valve mechanism provided in each supply flow path is closed and the suction pump of the maintenance mechanism is driven to depressurize the supply flow path on the downstream side of each valve mechanism. Then, after accumulating negative pressure in the downstream supply flow path, each valve mechanism is opened, and ink is forced to flow into the supply flow path where the pressure has decreased. As a result, the thickened ink and bubbles in the supply flow path and the recording head can be discharged from the nozzles of the recording head together with the ink having an increased flow velocity.

As this valve mechanism, an electromagnetic control valve equipped with an actuator can be used, but a valve mechanism that opens and closes according to the pressure of ink has also been proposed. As this valve mechanism, a valve mechanism is used in which a pressure chamber in which ink is temporarily stored is provided, and a partial wall surface of the pressure chamber is formed of a flexible film. In the pressure chamber, a valve seat having a discharge port opened on the surface facing the film is formed. When the ink in the pressure chamber decreases and the film bends inward, the film contacts the valve seat and shuts off the discharge port. Conversely, when the ink in the pressure chamber increases, the film opens away from the valve seat. It has become. That is, this valve mechanism has the advantage that it does not require electrical control and is structurally simpler than an electromagnetic control valve.
JP 2000-352379 A

  However, when a plurality of valve mechanisms are arranged as described above, the timing for opening the valve after accumulating negative pressure in the supply flow path may vary depending on individual differences. In this case, there is a possibility that only a small amount of ink flows in the supply flow path in which the valve mechanism having a slow valve opening timing is disposed, and the discharge performance of bubbles and the like is inferior.

  Further, when the diaphragm pump as described above is used as the pressurizing pump and the pump is small, a pressure capable of delivering ink into the cartridge is generated by repeating the exhausting operation a plurality of times. At this time, since the air is not pumped to the cartridge during the intake operation of the pump, the pressure applied to the ink in the cartridge rises intermittently as shown in the graph of FIG. That is, the pressure in the cartridge does not increase during the intake operation of the pump, but increases during the exhaust operation. For this reason, since the ink is discharged from the cartridge toward the on-off valve during the exhaust operation, discharge pulsation occurs, and the timing at which the valve mechanism opens is particularly likely to vary.

  On the other hand, it may be possible to lengthen the time during which the ink is pressure-fed into each supply channel so that a predetermined amount or more of ink flows in the supply channel in which the valve mechanism with a slow valve opening timing is provided. . However, in this case, since there is a problem that the amount of ink consumed during cleaning increases, it is desirable to suppress variation in timing at which each valve mechanism opens as much as possible.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid ejecting apparatus capable of performing choke cleaning with simple control and efficiently cleaning the liquid supply path without increasing the size of the apparatus. A cleaning method and a liquid ejecting apparatus are provided.

  According to the cleaning method of the liquid ejecting apparatus of the invention, the liquid supply path that guides the liquid in the liquid storage unit to the liquid ejecting head is provided with an opening / closing valve that opens and closes due to a pressure difference between the inside and the outside of the liquid supply path. The fluid in the nozzle is sucked by a suction means to close the on-off valve, and after reducing the flow path downstream from the on-off valve, the liquid storage means is pressurized by a pressurizing means, In the cleaning method for a liquid ejecting apparatus, the opening and closing valve is opened by the fluid pressure of the liquid delivered from the liquid storing means to discharge the fluid in the liquid supply path and the liquid ejecting head. The driving means for driving the pressure means is driven at a first speed, the liquid storage means is pressurized by the pressurizing means to open the on-off valve, and after the on-off valve is opened, the driving means is Said first speed Remote is driven by the small second speed, pressurizing the liquid storage means by said pressurizing means.

  According to this, the on-off valve is provided in the liquid supply path that communicates the liquid storage means and the liquid ejecting head. Then, the fluid is sucked from the nozzle of the liquid ejecting head by the suction means, whereby the on-off valve is closed and the flow path downstream of the on-off valve is decompressed. Further, the opening / closing valve is opened by the fluid pressure by the pressurizing means. For this reason, liquid is allowed to flow into the decompressed flow path at once, and impurities such as bubbles and thickened liquid in the liquid supply path downstream of the on-off valve and the liquid ejecting head are discharged together with the liquid having an increased flow velocity. So-called chalk cleaning can be performed.

  In addition, since the driving means for driving the pressurizing means is driven at a relatively high first speed after each of the on-off valves is closed, the pressurizing means operates at a relatively high speed, and the pressurizing means The time required from the start of driving until the on-off valve opens can be shortened. Therefore, the cleaning time can be shortened. Further, after the opening / closing valve is opened, the driving means is driven at the relatively low second speed, so that the load on the driving means and the pressurizing means can be reduced.

In the liquid ejecting apparatus cleaning method according to the present invention, each of the liquid supply paths that guide the liquid in the plurality of liquid storage units to the liquid ejecting head is provided with an opening / closing valve that opens and closes due to a pressure difference between the inside and the outside of each liquid supply path. The fluid in the nozzle formed in the liquid ejecting head is sucked by a suction means to close the open / close valves, and the flow paths downstream from the open / close valves are decompressed. Each of the storage means is pressurized by the pressurizing means, and each on-off valve is opened by the fluid pressure of the liquid delivered from each of the liquid storage means, and the fluid in each of the liquid supply paths and in the liquid ejecting head. In the cleaning method for a liquid ejecting apparatus, the driving unit that drives the pressurizing unit is driven at a first speed, and the liquid storing unit is pressurized by the pressurizing unit to open and close each Opening the, said drives the said drive means at a second speed less than the first speed after the valves have been opened, pressurizing the respective liquid storage means by said pressurizing means.

  According to this, each on-off valve is provided in each of the liquid supply paths that communicate with each liquid storage means and the liquid ejecting head. Then, each on-off valve is closed by sucking the fluid from the nozzle of the liquid ejecting head by the suction means, and the flow path downstream of each on-off valve is decompressed. Furthermore, each on-off valve is opened by the fluid pressure by the pressurizing operation of the pressurizing means. For this reason, liquid is allowed to flow into the decompressed flow path at once, and impurities such as bubbles and thickened liquid in the liquid supply paths and liquid jet heads downstream of the on-off valves are increased in flow rate. A so-called choke cleaning can be performed.

  In addition, since the driving means for driving the pressurizing means is driven at a relatively high first speed after each on-off valve is closed, the pressurizing means operates at a relatively high speed and pressurizes. It is possible to reduce the time required from the start of driving of the means to the opening of each on-off valve. Therefore, even if there is a variation in the opening timing of each on-off valve due to individual differences in each liquid supply path or each on-off valve, the variation can be reduced. Therefore, after opening each on-off valve, variation in the flow rate of the liquid flowing into the liquid supply path downstream of each on-off valve is suppressed, and impurities in each liquid supply path can be reduced without lengthening the cleaning time. Discharge properties and liquid filling properties can be improved. For this reason, each liquid supply path can be efficiently cleaned. In addition, after each on-off valve is opened, the driving means is driven at a relatively low second speed, so that the load applied to the driving means and the pressurizing means and the noise generated when the pressurizing means is driven at high speed are reduced. Can be reduced.

  In the cleaning method of the liquid ejecting apparatus, the pressurizing means is a diaphragm type pump having a diaphragm portion that constitutes an air chamber, and the diaphragm portion is displaced so as to reduce and expand the volume of the air chamber. The compressed air generated thereby is supplied to the liquid storage means, and the displacement speed of the diaphragm portion is changed according to the speed of the driving means.

  According to this, a pressurization means is a diaphragm type pump, Comprising: The diaphragm part which comprises an air chamber is provided. And the air produced | generated when the diaphragm part displaced so that the volume of an air chamber may be reduced and expanded is supplied to a liquid storage means. Further, this pump changes the displacement speed of the diaphragm portion according to the speed of the driving means. That is, this pump alternately repeats intake and exhaust operations and intermittently pumps air, but the diaphragm is displaced at high speed by driving the pump drive means at a relatively high first speed. The interval between each exhaust operation can be shortened. For this reason, since the pressure applied to the liquid storage means rises in a relatively short time, the pulsation of the liquid pumped from the liquid storage means to the on-off valve is suppressed, and variations in the timing at which the on-off valve opens are prevented.

  In the cleaning method for the liquid ejecting apparatus, the driving unit is driven at the first speed until a predetermined time, and the liquid storing unit is pressurized by the pressurizing unit and then is driven at the second speed. Then, the liquid storing means is pressurized by the pressurizing means.

  According to this, the drive means is driven at a relatively high first speed until a predetermined time to pressurize the liquid storage means, and then is driven at a relatively low second speed to store the liquid. Pressurize the means. For this reason, the reliability of the opening operation of the on-off valve can be ensured.

  In the cleaning method of the liquid ejecting apparatus, the fluid pressure of the liquid delivered from the liquid storage means is greater than the negative pressure generated by the suction means and closing the on-off valve during the predetermined time. It is time to become.

  According to this, the predetermined time is a time during which the fluid pressure of the liquid delivered from the liquid storage means is larger than at least the negative pressure that is sucked by the suction means and closes the on-off valve. For this reason, the reliability of the valve opening operation of the on-off valve can be improved.

  In the cleaning method of the liquid ejecting apparatus, the driving unit of the diaphragm pump is driven at the first speed until the number of displacements of the diaphragm portion reaches a predetermined number of displacements, and then at the second speed. Driven to pressurize each liquid storage means by the diaphragm pump.

  According to this, the driving means of the diaphragm pump is driven at a relatively low second speed after the diaphragm portion is driven at a relatively high first speed up to a predetermined number of displacements. For this reason, the diaphragm pump operates at a relatively small displacement speed after operating at a relatively large displacement speed up to a predetermined number of displacements. For this reason, even when the diaphragm pump is downsized and the on-off valve is opened, it is possible to reliably pressurize the liquid storage means even when the pump needs to repeat a plurality of displacement operations.

  In the cleaning method of the liquid ejecting apparatus, the predetermined number of displacements is more than a negative pressure at which the fluid pressure of the liquid delivered from the liquid storage unit is generated by at least the suction unit and the on-off valve is closed. It is the number of times to increase.

  According to this, the predetermined number of displacements is the number of times that the fluid pressure of the liquid delivered from the liquid storage means becomes greater than at least the negative pressure that is sucked by the suction means and closes the on-off valve. For this reason, the reliability of the valve opening operation of the on-off valve can be improved.

  In the cleaning method of the liquid ejecting apparatus, the pressurizing unit is a pump that pressurizes the liquid storing unit and supplies the liquid to the liquid ejecting head for the liquid ejecting operation of the liquid ejecting head.

  According to this, the pressurizing means has a function of pressurizing the liquid storage means and supplying the liquid to the liquid ejecting head for the liquid ejecting operation of the liquid ejecting apparatus. For this reason, the pump having the liquid supply function can be used as a pressurizing means for opening the on-off valve, so that the number of parts of the apparatus can be reduced.

  In the cleaning method of the liquid ejecting apparatus, the diaphragm portion of the diaphragm pump is an expansion / contraction member having the air chamber therein and having a side wall formed in an accordion shape, and the expansion / contraction member is a member of the driving unit. Change the speed of expansion and contraction according to the speed.

  According to this, the diaphragm part of the diaphragm pump is an expansion / contraction member provided with an air chamber inside and having a side wall formed in a bellows shape. Moreover, since the expansion / contraction member changes the speed of the expansion / contraction operation according to the speed of the driving means, when the driving means is driven at the first speed, the time required for the expansion / contraction member to extend can be shortened.

In the liquid ejecting apparatus according to the aspect of the invention, an on-off valve that opens and closes according to a pressure difference between the inside and the outside of each of the liquid supply paths is provided in each of the liquid supply paths that guide the liquid in the plurality of liquid storage units to the liquid ejecting head. The fluid in the nozzle formed in the ejection head is sucked by the suction means to close each of the on-off valves, and after reducing the pressure of each flow path downstream of the on-off valves, the liquid storage means Pressurization is performed by the pressurizing means, and the on-off valves are opened by the fluid pressure of the liquid delivered from the liquid storage means to discharge the fluid in the liquid supply paths and the liquid ejecting head. The liquid ejecting apparatus configured as described above further includes a driving unit that drives the pressurizing unit, and the driving unit is driven at a first speed to pressurize each of the liquid storage units with the pressurizing unit. Open each on-off valve, After the on-off valve is opened is driven by the smaller than the first speed the second speed, pressurizing the respective liquid storage means by said pressurizing means.

  According to this, each on-off valve is provided in each of the liquid supply paths that communicate with each liquid storage means and the liquid ejecting head provided in the liquid ejecting apparatus. Then, each on-off valve is closed by sucking the liquid from the nozzle of the liquid ejecting head by the suction means, and the flow path downstream of each on-off valve is decompressed. Furthermore, each on-off valve is opened by the fluid pressure by driving the pressurizing means. For this reason, liquid is allowed to flow into the decompressed flow path at once, and impurities such as bubbles and thickened liquid in the liquid supply paths and liquid jet heads downstream of the on-off valves are increased in flow rate. A so-called choke cleaning can be performed.

  In addition, the liquid ejecting apparatus includes a driving unit that drives the pressurizing unit, and the driving unit is driven at a relatively high first speed after each on-off valve is closed. The time required from the start of driving of the means to the opening of the on-off valve can be shortened. Therefore, even if there is a variation in the opening timing of each on-off valve due to individual differences in each liquid supply path or on-off valve, the variation can be reduced. Therefore, after opening the on-off valve, variation in the flow rate of the liquid flowing in the liquid supply path downstream from the on-off valve is suppressed, and the drainage of impurities in each liquid supply path and the liquid can be achieved without lengthening the cleaning time. Fillability can be improved. For this reason, the inside of a liquid supply path can be cleaned efficiently. Further, after the opening / closing valve is opened, the driving means is driven at a relatively low second speed, so that the load applied to the pressurizing means and noise generated when the pressurizing means is driven at high speed can be reduced.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. FIG. 1 is a plan view illustrating a schematic configuration of an ink jet recording apparatus (hereinafter simply referred to as a printer) as a liquid ejecting apparatus.

  As shown in FIG. 1, the printer 1 includes a frame 2, and a platen 3 is installed on the frame 2. On the platen 3, paper is fed by a paper feed mechanism having a paper feed motor M2 (see FIG. 9). A rod-shaped guide member 4 is installed on the frame 2 in parallel with the longitudinal direction of the platen 3. A carriage 5 is inserted into and supported by the guide member 4 so as to reciprocate in the axial direction of the guide member 4. The carriage 5 is drivingly connected to a carriage motor 7 via a timing belt 6 stretched around each pulley 6a. Therefore, the carriage 5 is reciprocated along the guide member 4 by driving the carriage motor 7.

  A recording head 8 as a liquid ejecting head is mounted on the surface of the carriage 5 facing the platen 3. On the carriage 5, six valve units 9 that supply temporarily stored liquid and fluid ink to the recording head 8 are mounted. Four valve units 9 are provided corresponding to the color (type) of ink used in the printer 1. A nozzle N (see FIG. 3) is provided on the lower surface of the recording head 8, and ink droplets are ejected from the ejection port of the nozzle N onto the paper transported on the platen 3.

A cartridge holder 10 is provided at the right end of the frame 2. The cartridge holder 10 is provided with four cartridges 11 as liquid storage means so as to be detachable. As shown in FIG. 2, these cartridges 11 are configured by a case 12 that is airtight inside and an ink pack 13 provided inside the case 12. Each ink pack 13 is filled with various inks inside a flexible film formed in a bag shape. These ink packs 13 and each valve unit 9 on the carriage 5 are connected to each other via an ink supply path 14 as a liquid supply path. Each ink supply path 14 includes a tube made of a flexible material, a flow path formed for a hard resin material, and the like.

  A pressure unit 15 is mounted on the right end in the frame 2. The pressurizing unit 15 is a device that pumps pressurized air to the cartridge 11 through the air supply path 16, and includes a pressurizing pump 20, a pressure sensor 21, and an air release valve 22 as pressurizing means. The air supply path 16 branches into a plurality (four in this embodiment) with a distributor 23 downstream of the atmosphere release valve 22 as a boundary, and is connected to each cartridge 11.

  The case 12 of each cartridge 11 is formed with a through hole 18 connected to a space 17 provided between the case 12 and the ink pack 13. Each branched air supply is supplied to each through hole 18. A path 16 is connected. Therefore, when the pressurization pump 20 of the pressurization unit 15 is driven, the air pumped from the pressurization pump 20 is introduced into the space 17 in the cartridge 11 via the air supply path 16. When the space 17 is filled with air in a high pressure state, the ink pack 13 is crushed by the air pressure. As a result, the ink in the ink pack 13 is pushed out to the ink supply path 14 and supplied to the valve unit 9.

  A maintenance unit 25 is disposed at the end of the frame 2 and at the home position of the carriage 5. FIG. 3 is a schematic diagram of the maintenance unit 25. The maintenance unit 25 includes a cap 26 as shown in FIG. The cap 26 is formed in a box shape whose upper surface is open, and is connected to an elevating mechanism 32 (see FIG. 9). The elevating mechanism 32 includes a gear mechanism using a maintenance motor M4 (see FIG. 9) as a drive source and a cam function (not shown). When the carriage 5 moves to the home position, the cap 26 is moved to the recording head 8. The nozzles N of the recording head 8 are sealed in an airtight state to prevent drying. Further, a discharge port 28 is formed through the bottom wall portion of the cap 26, and a discharge tube 29 is connected to the discharge port 28. A suction pump 30 as a suction means is provided in the middle of the discharge tube 29. The suction pump 30 is a tube pump, a gear pump or the like using the maintenance motor M4 as a common drive source, and the tip of the discharge tube 29 is connected to the waste ink tank T.

  The maintenance unit 25 performs so-called choke cleaning using the valve unit 9 on the carriage 5. First, the valve unit 9 will be described with reference to FIGS. 4 and 5 are cross-sectional views of the main part of the valve unit 9.

  As shown in FIG. 4, the valve unit 9 includes a base material 35 made of synthetic resin, and a recess 36 is formed on one side surface of the base material 35. In the bottom surface of the recess 36, an introduction path 37 formed through the base material 35 is opened. The introduction path 37 communicates with the ink supply path 14 connected to the cartridge 11. Further, a protrusion 39 is formed on the bottom surface of the recess 36, and a discharge path 38 is opened on the top surface of the protrusion 39. The discharge path 38 is formed through the base material 35 and communicates with the recording head 8 side.

Further, the recess 36 is sealed by fixing the film 40 made of a flexible material to one side surface of the base material 35 in a state where the recess 36 is slackened. Thus, a sealed pressure chamber 41 is formed by the inner surface of the recess 36 and the film 40. Therefore, when ink is supplied from the ink supply path 14 to the valve unit 9, the ink flows into the pressure chamber 41 through the introduction path 37. When the ink in the pressure chamber 41 increases, the film 40 moves away from the protrusion 39 as shown in FIG. When the amount of ink in the pressure chamber 41 further increases and the pressure received from the ink increases, the film 40 swells upward. In the present embodiment, the recess 36, the film 40, the protrusion 39, and the like constitute a choke valve B as an on-off valve.

  At the time of chalk cleaning, the suction pump 30 is driven with the cap 26 in contact with the lower surface of the recording head 8. Then, air and ink in the cap inner space 31 formed by the lower surface of the recording head 8 and the inner surface of the cap 26 are sucked and discharged through the discharge tube 29 to the discharge tube 29 side. As a result, the cap inner space 31 is in a negative pressure state, and this negative pressure acts on the nozzle N of the recording head 8, and the ink in the recording head 8 is ejected from the nozzle N to the cap inner space 31.

  Further, when the suction pump 30 is driven, ink in the valve unit 9 as well as in the recording head 8 is sucked. As a result, the ink in the pressure chamber 41 is discharged downstream from the ejection path 38, and the ink in the pressure chamber 41 decreases. When the suction pump 30 continues to be driven, the film 40 is displaced toward the protrusion 39 as the ink in the pressure chamber 41 decreases, and finally comes into contact with the protrusion 39 as shown in FIG. Occlude. As the suction pump 30 is driven, the flow path downstream of the discharge path 38 inlet is further depressurized.

  When the negative pressure is accumulated in the flow path downstream of the pressure chamber 41, the pressurizing pump 20 starts to be driven. Then, ink is supplied from the cartridge 11 to the valve unit 9 and introduced into the pressure chamber 41. As a result, as the amount of ink delivered to the pressure chamber 41 increases, the film 40 is displaced in a direction away from the protrusion 39, and the discharge path 38 is opened. As a result, the ink flows into the ejection path 38 in which the negative pressure is accumulated at once, and bubbles, thickened ink, and the like as fluid staying in the ink flow path and the recording head 8 on the downstream side of the pressure chamber 41 increase the flow velocity. The ink is discharged from the nozzle N of the recording head 8 together with the ink that has been discharged. In this way, so-called chalk cleaning can be performed. Further, the ink discharged from the nozzles of the recording head 8 is discharged to the waste ink tank T.

  Next, the pressurizing unit 15 will be described in detail with reference to FIG. FIG. 6 is a plan view of the pressure unit 15. The pressurizing pump 20, the pressure sensor 21 and the atmosphere release valve 22 are unitized by being attached to the mounting plate 44. The pressurizing pump 20 is a diaphragm type pump (a positive displacement pump), and includes a telescopic member 46 as a diaphragm portion made of a covered cylindrical resin having a side wall formed in a bellows shape. An air chamber 47 (see FIG. 7) is provided inside the elastic member 46, and the air chamber 47 is sealed by a sealing portion 48. An exhaust tube 49 for pumping air from the pressurizing pump 20 is connected to the sealing portion 48.

  A pressing member 50 is fitted to the distal end of the elastic member 46. The pressing member 50 includes a flat base 51 and a piston 52 integrally formed with the base 51. A cam groove (not shown) is formed on the outer peripheral surface of the piston 52. The pressing member 50 includes a first gear 53 that can be inserted through the piston 52. The first gear 53 is supported so as to be relatively rotatable about the piston 52.

A sliding portion 54 is disposed between the base portion 51 and the first gear 53. The sliding portion 54 is attached to a protruding portion 53a formed integrally with the first gear 53, and a projection (not shown) that slides on the cam groove formed on the outer peripheral surface of the piston 52 on the back side thereof. It has. Therefore, when the first gear 53 rotates with respect to the piston 52, the sliding portion 54 revolves around the piston 52, and the projection slides in the cam groove of the piston 52. Then, the piston 52 performs a reciprocating linear motion in parallel with the arrow A direction and the arrow B direction in the drawing based on the shape of the cam groove. As a result, the expansion / contraction member 46 locked to the base 51 also expands / contracts according to the reciprocating linear motion and increases / decreases the volume of the air chamber 47, thereby pumping air from the exhaust tube 49. In the present embodiment, the piston 52 and the sliding portion 54 constitute a cam mechanism 55.

  The mounting plate 44 is provided with a pump motor 45 as a driving means that is a driving source of the pressure pump 20. The pump motor 45 is a motor that can rotate in forward and reverse directions. A motor gear 56 is attached to the output shaft of the pump motor 45. In addition, a wall 44a is erected on the end edge of the mounting plate 44, and a support shaft 57 is formed on the wall 44a. A second gear 58 that can mesh with the motor gear 56 is rotatably supported on the support shaft 57. Further, the second gear 58 meshes with the first gear 53 of the pressure pump 20. In the present embodiment, the motor gear 56, the first gear 53, and the second gear 58 constitute a gear mechanism 59. Therefore, the rotational motion of the pump motor 45 is transmitted by the gear mechanism 59 and converted into a reciprocating linear motion by the cam mechanism 55, and the telescopic member 46 is expanded and contracted.

  7 and 8 are side sectional views schematically showing the elastic member 46. The sealing portion 48 of the elastic member 46 is provided with an intake passage 60 and an exhaust passage 61 that communicate with the air chamber 47. The intake passage 60 has an inlet on the side opposite to the air chamber 47 opened to the atmosphere. The exhaust path 61 communicates with an exhaust tube 49 connected to the sealing portion 48. The intake passage 60 is connected to an intake permissible valve 62 that is a one-way valve that allows only the flow of air from the atmosphere toward the air chamber 47, and the exhaust passage 61 is connected to the air from the air chamber 47 to the atmosphere. An exhaust allowable valve 63, which is a one-way valve that allows only flow, is connected.

  When the piston 52 moves in the direction indicated by the arrow A by driving the gear mechanism 59 and the cam mechanism 55, the telescopic member 46 contracts as shown in FIG. 8 (exhaust operation). At this time, the air in the air chamber 47 is pumped to the exhaust tube 49 through the exhaust path 61. From this state, when the piston 52 moves in the direction of arrow B, the expandable member 46 extends as shown in FIG. 7 (intake operation). At this time, the atmosphere is introduced into the air chamber 47 through the intake passage 60. When the pressurizing pump 20 repeats the intake operation and the exhaust operation, air is pumped through the exhaust tube 49, and the pressure in the space 17 of the cartridge 11 increases stepwise.

  As shown in FIG. 6, the pressure sensor 21 is connected to an exhaust tube 49 of the pressurizing pump 20. The pressure sensor 21 is a sensor capable of detecting the pressure of air exhausted from the pressurizing pump 20 and outputting a detection value corresponding to the pressure. An atmospheric release valve 22 is connected to the pressure sensor 21 via a communication pipe 64.

  The air release valve 22 is provided between the communication pipe 64 and the air supply path 16 and includes a valve release lever 65. When the valve release lever 65 is pushed in, the air release valve 22 acts to open the air supply path 16 to the atmosphere. In a state where the valve release lever 65 is not pushed, the air supply path 16 is not opened to the atmosphere, and the air pumped from the pressurizing pump 20 is supplied to the cartridge 11 via the air supply path 16. . A valve opening mechanism (not shown) is provided in the vicinity of the valve opening lever 65. The valve opening mechanism includes a gear mechanism connected to the pump motor 45 and a pressing member capable of pressing the valve opening lever 65, and presses the valve opening lever 65 when the pump motor 45 rotates in the reverse direction.

Further, as shown in FIG. 6, a home detector 67 for detecting the position of the telescopic member 46 is attached in the vicinity of the pressing member 50 of the pressurizing pump 20. The home detector 67 includes a limit switch, a photo sensor, and the like, and includes a detection lever 68. When the telescopic member 46 is fully extended, that is, when the telescopic member 46 is disposed at the home position, the base 51 of the pressing member 50 pushes the detection lever 68. When the detection lever 68 is pushed, the home detector 6
7 outputs a detection signal.

  Next, the electrical configuration of the printer 1 will be described with reference to FIG. The printer 1 includes a CPU 70, a ROM 71, a RAM 72, and an ASIC 73, and these devices are connected by a bus 74. The CPU 70 performs main control using the RAM 72 as a work area based on various control programs stored in the ROM 71. The printer 1 is connected to the host computer C via the I / F 75 and performs a printing operation based on the print data transmitted from the host computer C.

  The ASIC 73 operates based on a command from the CPU 70 and drives the first to fourth motor drive circuits 76 to 79 and the like. The first motor drive circuit 76 controls the carriage motor 7 and the second motor drive circuit 77 controls the paper feed motor M2. The third motor drive circuit 78 drives a pump motor 45 that is a drive source such as the pressurizing pump 20. The pump motor 45 is controlled to be rotatable at the first to third rotational speeds based on each signal output from the ASIC 73. The first rotational speed as the first speed has the largest rotational speed, and the second rotational speed as the second speed is smaller than the first rotational speed. The third rotation speed is the minimum rotation speed among the modes set for the pump motor 45, and rotates at the third rotation speed during the printing operation.

  The fourth motor drive circuit 79 drives the maintenance motor M4 provided in the maintenance unit 25. Further, the ASIC 73 drives a piezoelectric element (not shown) of the recording head 8 via the head drive circuit 80 to perform an ink ejection operation (liquid ejection operation) for ejecting ink droplets from the nozzles N.

  The ASIC 73 is electrically connected to the pressure sensor 21 and calculates the pressure value of the pressurized air based on the detection value output from the pressure sensor 21. Then, the ASIC 73 controls the drive of the pump motor 45 via the third motor drive circuit 78 based on the calculated pressure value. Further, the ASIC 73 is electrically connected to the home detector 67, and determines that the telescopic member 46 is disposed at the home position based on the detection signal output from the home detector 67. The ASIC 73 determines the driving time of the maintenance motor M4 and the like based on the output value of the timer 81.

  Next, a processing procedure at the time of chalk cleaning will be described with reference to FIG. The ASIC 73 has an operation unit 82 (see FIG. 9) provided at a predetermined period or in an outer case (not shown) that accommodates the frame 2 when the printer 1 is in a non-printing state and the carriage 5 is disposed at the home position. Based on the signal from, choke cleaning is performed according to the cleaning program stored in the ROM 71.

  First, the ASIC 73 drives the maintenance motor M4 via the fourth motor drive circuit 79 and starts the suction operation (step S1-1). At this time, the cap 26 is disposed at the operating position in contact with the lower surface of the recording head 8 by the lifting mechanism 32. Then, by driving the maintenance motor M4, the suction pump 30 starts to drive, and the recording head 8 and ink in the ink flow path on the upstream side are sucked and discharged. Then, the ink in the valve unit 9 provided on the upstream side of the recording head 8 is also discharged, and the ink in the pressure chamber 41 decreases. When the suction pump 30 continues to drive, the film 40 comes into contact with the protrusion 39 and the discharge path 38 is closed as the ink decreases. A negative pressure is accumulated downstream of the pressure chamber 41.

Next, the ASIC 73 determines whether or not a predetermined time T1 has elapsed since the maintenance motor M4 started driving based on the measured value by the timer 81 (step S1-2). The predetermined time T1 is a value obtained by experiments or the like in advance for the time for accumulating negative pressure in the ink flow path for performing choke cleaning. If predetermined time T1 has not been reached (NO in step S1-2), step S1-2 is repeated. If the predetermined time T1 has elapsed (YES in step S1-2), the process proceeds to step S1-3.

  In step S1-3, the pressurizing pump 20 is driven at high speed. Specifically, the pump motor 45 is rotated forward at the first rotational speed by the output signal of the ASIC 73. Accordingly, the expansion / contraction speed (displacement speed) of the expansion / contraction member 46 is increased, and the time per reciprocation of the expansion / contraction member 46 is shortened, so that the time between each exhaust operation of the pressurizing pump 20 is shortened. As a result, the ejection pulsation of the ink pumped from the cartridge 11 is eliminated or the pulsation interval is shortened, the ink in the pressure chamber 41 increases in a relatively short time, and the film 40 is separated from the protrusion 39. Variation in the opening timing is suppressed. As a result, the ink flows immediately downstream from each pressure chamber 41. Thus, since the variation in opening of each choke valve B is suppressed, the ink flow rate sent from the cartridge 11 during the choke cleaning is set to be a relatively small amount.

  Next, the ASIC 73 determines whether or not a predetermined time T2 has elapsed since the pump motor 45 started driving based on the measured value by the timer 81 (step S1-4). The predetermined time T2 is a time when the fluid pressure of the ink pumped from the cartridge 11 becomes larger than the negative pressure closing the choke valve B, starting from the time when the pump motor 45 starts to drive. If predetermined time T2 has not been reached (NO in step S1-4), step S1-4 is repeated. When the predetermined time T2 has elapsed (YES in step S1-4), the pressure pump 20 is driven at a low speed (step S1-5). At this time, the ASIC 73 rotates the pump motor 45 forward at the second rotational speed to reduce the expansion / contraction speed of the expansion / contraction member 46. For this reason, noise generated when the pressurizing pump 20 is driven at high speed is reduced.

  Even if the rotational speed of the pump motor 45 is reduced, the ink sent from the cartridge 11 flows toward the downstream side vigorously due to the pressure difference formed in the ink flow path. However, the flow velocity of the ink flowing downstream does not decrease. Even if the suction pump 30 is driven, the ink is pumped from the cartridge 11 to the pressure chamber 41 by continuing to pump the air by the pressurizing pump 20, so that the choke valve B maintains the valve open state.

  Next, the ASIC 73 determines whether the air pressure in the air flow path is equal to or higher than the predetermined pressure P1 based on the detection value of the pressure sensor 21 (step S1-6). The predetermined pressure P1 is a pressure at which the ink pack 13 is pressed and ink can be delivered to the ink flow path side. If it is not equal to or higher than the predetermined pressure P1 (NO in step S1-6), step S1-6 is repeated. If the pressure is equal to or higher than the predetermined pressure P1 (YES in step S1-6), the suction operation is stopped (step S1-7). Specifically, first, the ASIC 73 drives the maintenance motor M4 to prevent the negative pressure in the cap 26 from acting on the nozzle N. For example, an atmosphere release valve (not shown) communicating with the cap 26 is opened, and the cap internal space 31 becomes atmospheric pressure. At this time, the suction pump 30 performs idle suction for sucking ink or the like in the cap 26. Thereafter, the driving of the maintenance motor M4 is stopped, and the suction pump 30 is stopped.

  Next, the ASIC 73 stops the pressurizing pump 20 (step S1-8). At this time, the ASIC 73 rotates the pump motor 45 in the reverse direction to extend the telescopic member 46 to the home position, and then stops the rotation of the pump motor 45. In this way, by appropriately performing chalk cleaning, bubbles and impurities in the ink flow path and the recording head 8 are discharged, and ink filling properties can be improved.

According to the above embodiment, the following effects can be obtained.
(1) According to the above embodiment, the valve unit 9 that supplies ink to the recording head 8
A choke valve B provided with a pressure chamber 41 having a part of the wall made of a film 40 was provided. Then, the suction pump 30 of the maintenance unit 25 is driven to suck and discharge ink from the nozzles N of the recording head 8, thereby reducing the pressure in the flow path and the pressure chamber 41 and closing the choke valve B by the fluid pressure. I made it. Further, by continuing to drive the suction pump 30, negative pressure is accumulated in the flow path downstream of the pressure chamber 41, and then the ink is pumped to the pressure chamber 41 by driving the pressurizing pump 20, so that the fluid pressure Thus, the choke valve B is opened. For this reason, the ink is sent all at once to the downstream ink flow path in which the negative pressure is accumulated, and the bubbles in the ink flow path including the recording head 8 and the thickened ink are combined with the ink with the increased flow velocity. So-called choke cleaning can be performed by discharging from the nozzle N. Therefore, without using an electromagnetic control valve or the like, it is possible to prevent the apparatus from becoming large and to easily perform choke cleaning.

  In addition, after the choke valves B are closed, the pump motor 45 is driven at the first rotational speed and the pressurizing pump 20 is driven at a high speed. The time required for opening the valve can be shortened. Therefore, even if there is a variation in the timing at which each choke valve B opens due to individual differences in each ink flow path or choke valve B, the variation can be reduced. For this reason, after the choke valve B is opened, the variation in the flow rate of the ink pumped to the flow path downstream of the choke valve B is suppressed, and the impurities in each ink flow path are discharged without lengthening the cleaning time. Property and liquid filling property can be improved. That is, the ink flow path can be efficiently cleaned without increasing the amount of ink consumed during cleaning. In addition, after the choke valve B is opened, the pump motor 45 is driven at the second rotational speed and the pressurizing pump 20 is driven at a low speed. The generated noise can be reduced.

  (2) In the above embodiment, the fluid pressure of the ink pumped from the cartridge 11 is sucked by the suction pump 30 and the choke valve B is closed during the predetermined time T2 when the pressure pump 20 is driven at high speed. It is time to become larger than the negative pressure. For this reason, the choke valve B can be opened reliably.

  (3) In the said embodiment, the pressurization pump 20 comprised the diaphragm type pump (bellows type pump) provided with the expansion-contraction member 46 which has the air chamber 47. FIG. The compressed air generated by the expansion / contraction of the expansion / contraction member 46 is supplied to the cartridge 11. For this reason, the pressurization pump 20 can be downsized and the pump efficiency can be improved. Further, even if the pressurizing pump 20 intermittently pumps air, the intervals between the exhaust operations can be shortened by driving at high speed. For this reason, it is possible to shorten the interval between the ejection pulsations of the ink delivered from the cartridge 11 and suppress the variation in the timing at which the choke valve B opens.

In addition, you may change this embodiment as follows.
In the processing of step S1-4 at the time of chalk cleaning, as shown in the processing procedure of FIG. 11, it may be determined whether or not the number of expansions / contractions (the number of displacements) of the expansion / contraction member 46 is equal to or greater than a predetermined number K. (Step S1-9). The predetermined number of times K is the number of expansion / contractions of the expansion / contraction member 46 in which the fluid pressure of the ink delivered from the cartridge 11 is at least greater than the negative pressure sucked by the suction pump 30 and closing the choke valve B. It is. In this way, the occurrence of variations due to individual differences can be further prevented.

  -The pressurization pump 20 may be provided with diaphragm parts other than the expansion-contraction member 46 formed in the bellows shape. For example, a part of the wall surface of the air chamber may be constituted by a diaphragm that can be displaced by the diaphragm driving means, and the volume of the air chamber may be reduced and enlarged by the displacement operation of the diaphragm.

-In above-mentioned embodiment, although the pressurization pump 20 was comprised from the diaphragm type pump, you may comprise from pumps other than this.
The printer 1 (liquid ejecting apparatus) of the above-described embodiment may be applied to a printer (liquid ejecting apparatus) including one cartridge 11, ink supply path 14, choke valve B, and the like.

  In the above embodiment, the choke valve B is provided in the valve unit 9, but may be provided anywhere in the ink flow path from the cartridge 11 to the nozzle N of the recording head 8.

The printer 1 may be provided with a plurality of cartridges 11 other than four.
In the above embodiment, a pressurizing pump for pumping ink to the choke valve B to open it and a supply mechanism for supplying ink to the recording head 8 may be provided separately. In this case, the supply mechanism may be configured by a holder, a tube, or the like that provides the cartridge 11 vertically above the recording head 8 and supplies ink to the recording head 8 by a water head difference.

  In the above embodiment, the printer 1 that ejects ink has been described as the liquid ejecting apparatus, but other liquid ejecting apparatuses may be used. For example, printing apparatuses including fax machines, copiers, etc., liquid ejecting apparatuses that eject liquids such as electrode materials and coloring materials used in the production of liquid crystal displays, EL displays, and surface-emitting displays, and bio-organic materials used in biochip manufacturing It may be a liquid ejecting apparatus for ejecting a liquid or a sample ejecting apparatus as a precision pipette. The fluid (liquid) is not limited to ink, and may be applied to other fluids.

FIG. 2 is a plan view of a main part of the printer according to the embodiment of the invention. Sectional drawing of the cartridge with which the printer is equipped. FIG. 2 is a schematic diagram of a maintenance unit provided in the printer. FIG. 3 is a cross-sectional view of a main part of a valve unit provided in the printer. Sectional drawing of the principal part of the valve unit. The top view of the pressurization unit with which the printer is equipped. The sectional side view of the expansion-contraction member with which the pressurization pump of the pressurization unit is equipped. The sectional side view of the expansion-contraction member. FIG. 2 is a block diagram of the printer. Explanatory drawing of the processing procedure of chalk cleaning of the printer. Explanatory drawing of the process sequence of another example. Explanatory drawing explaining the pressure change in a cartridge.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer as a liquid ejecting apparatus, 8 ... Recording head as a liquid ejecting head, 11 ... Cartridge as a liquid storage means, 14 ... Ink supply path as a liquid supply path, 20 ... As a pressurizing means and a diaphragm pump Pressure pump, 30 ... Suction pump as suction means, 45 ... Pump motor as drive means, 46 ... Expandable member as diaphragm, 47 ... Air chamber, B ... Choke valve as on-off valve, K ... As number of displacement Number of expansion / contraction, T1, T2 ... predetermined time, N ... nozzle.

Claims (10)

An opening / closing valve that opens and closes due to a pressure difference between the inside and outside of the liquid supply path is provided in the liquid supply path that guides the liquid in the liquid storage means to the liquid jet head, and the fluid in the nozzle formed in the liquid jet head is sucked by the suction means. After suction, the on-off valve is closed and the flow path downstream of the on-off valve is depressurized, and then the liquid storage means is pressurized by the pressurization means, and the fluid pressure of the liquid delivered from the liquid storage means In the cleaning method of the liquid ejecting apparatus in which the on-off valve is opened to discharge the fluid in the liquid supply path and the liquid ejecting head.
Driving the driving means for driving the pressurizing means at a first speed, pressurizing the liquid storing means by the pressurizing means to open the on-off valve;
A liquid ejecting apparatus comprising: driving the driving unit at a second speed smaller than the first speed after the opening / closing valve is opened, and pressurizing the liquid storing unit by the pressurizing unit. Cleaning method. In each of the liquid supply passages for guiding the liquid of the plurality of liquid storage means to the liquid ejecting head, an open / close valve that opens and closes due to a pressure difference between the inside and the outside of each liquid supply passage is provided, and an inside of the nozzle formed in the liquid ejecting head The fluid is sucked by the suction means, the open / close valves are closed, the flow paths downstream of the open / close valves are depressurized, and then the liquid storage means are pressurized by the pressurizing means. The cleaning of the liquid ejecting apparatus in which the on-off valves are opened by the fluid pressure of the liquid delivered from the liquid storing means to discharge the fluid in the liquid supply paths and the liquid ejecting head. In the method
Driving the driving means for driving the pressurizing means at a first speed, pressurizing the liquid storing means by the pressurizing means to open the open / close valves;
The liquid is characterized in that, after the opening / closing valves are opened, the driving means is driven at a second speed smaller than the first speed, and the liquid storing means is pressurized by the pressurizing means. Cleaning method for spray device. In the cleaning method of the liquid ejecting device according to claim 1 or 2,
The pressurizing means is a diaphragm type pump having a diaphragm portion constituting an air chamber, wherein the compressed air generated by the displacement of the diaphragm portion so as to reduce and expand the volume of the air chamber A cleaning method for a liquid ejecting apparatus, comprising: supplying to a liquid storing means; and changing a displacement speed of the diaphragm portion according to a speed of the driving means. In the cleaning method of the liquid ejecting device according to any one of claims 1 to 3,
The driving means is driven at the first speed until a predetermined time, pressurizes the liquid storage means by the pressurizing means, and then is driven at the second speed and the liquid by the pressurizing means. A method for cleaning a liquid ejecting apparatus, comprising pressurizing a storage means. The liquid ejecting apparatus cleaning method according to claim 4,
The predetermined time is a time when the fluid pressure of the liquid delivered from the liquid storage means is at least greater than the negative pressure generated by the suction means and closing the on-off valve. A method for cleaning a liquid ejecting apparatus. The method for cleaning a liquid ejecting apparatus according to claim 3,
The driving means of the diaphragm pump is driven at the first speed until the number of displacements of the diaphragm portion reaches a predetermined number of displacements, and then driven at the second speed, and is driven by the diaphragm pump. A method of cleaning a liquid ejecting apparatus, comprising pressurizing each of the liquid storage means. The method of cleaning a liquid ejecting apparatus according to claim 6.
The predetermined number of displacements is a number of times that the fluid pressure of the liquid delivered from the liquid storage means is greater than at least a negative pressure generated by the suction means and closing the on-off valve. Cleaning method for liquid ejecting apparatus. In the cleaning method of the liquid ejecting device according to any one of claims 1 to 7,
The liquid ejecting apparatus cleaning method, wherein the pressurizing unit is a pump that pressurizes the liquid storage unit and supplies the liquid to the liquid ejecting head for the liquid ejecting operation of the liquid ejecting head. In the cleaning method of the liquid ejecting device according to any one of claims 3 to 8,
The diaphragm portion of the diaphragm pump is an expansion / contraction member provided with the air chamber therein and having a side wall formed in a bellows shape,
The method of cleaning a liquid ejecting apparatus according to claim 1, wherein the expansion and contraction member changes a speed of the expansion and contraction operation according to a speed of the driving unit. In each of the liquid supply passages for guiding the liquid of the plurality of liquid storage means to the liquid ejecting head, an open / close valve that opens and closes due to a pressure difference between the inside and the outside of each liquid supply passage is provided, and an inside of the nozzle formed in the liquid ejecting head is provided. The fluid is sucked by the suction means, the open / close valves are closed, the flow paths downstream of the open / close valves are depressurized, and then the liquid storage means are pressurized by the pressurizing means. In the liquid ejecting apparatus, each of the on-off valves is opened by the fluid pressure of the liquid sent from each of the liquid storing means so that the fluid in each of the liquid supply paths and the liquid ejecting head is discharged.
Drive means for driving the pressurizing means;
The driving means is driven at a first speed, pressurizes the liquid storage means with the pressurizing means, opens the on-off valves, and opens the on-off valves after the on-off valves are opened. A liquid ejecting apparatus that is driven at a second speed lower than the first speed and pressurizes each liquid storing means by the pressurizing means.

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