JP2006224566A - Filling method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid delivering device which is excellent in delivering reliability. <P>SOLUTION: In the liquid delivering device, a pressure adjusting mechanism 17a for feeding ink to a delivering head 14 comprises a pressure chamber 240 which is an expanded flow channel relative to cylindrical flow channels 251 and 253, and a buffer section 61 communicating with the pressure chamber 240 via a communication channel 52. The buffer section 61 has its capacity variable according to internal pressure of the pressure chamber 240. Herein, suction is carried out from nozzles 45 of the delivering head 14 to contract the capacity of the buffer section 61 by a maintenance unit 25, and by virtue of an effect of delivering of air in the pressure chamber 240 via a communication port 51, occurring when the contracted capacity is recovered, the ink filling ability of the pressure chamber 240 is enhanced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid filling method in a liquid ejecting apparatus that performs drawing by ejecting liquid, such as an ink jet recording apparatus, a display manufacturing apparatus, an electrode forming apparatus, or a biochip manufacturing apparatus.

  2. Description of the Related Art Conventionally, an ink jet printer is known as a liquid ejecting apparatus that ejects liquid from nozzles of an ejection head. Some ink jet printers (printers) include a so-called off-carriage type supply system in which a liquid container (ink cartridge) is mounted at a place other than a carriage. Specifically, an ink cartridge and an ejection head are provided. A tubular channel to be connected is formed and liquid (ink) is supplied. Further, in recent years, a configuration including a pressure damper mechanism that buffers ink supply pressure fluctuations accompanying movement of the carriage in the middle of the flow path (for example, Patent Document 1), or supply pressure from the ink cartridge side is provided. There is also known a configuration including a pressure adjustment mechanism that reduces pressure and generates an appropriate negative pressure on the ejection head side (for example, Patent Document 2).

  By the way, a liquid discharge apparatus provided with the above supply systems has the peculiar subject by handling a liquid. For example, when bubbles remain in the supply flow path, such bubbles may flow out into the fine flow path of the discharge head and close the flow path, thereby making it impossible to normally discharge the liquid. For this reason, it is one of the important technical problems to improve the filling property of the liquid in the supply flow path in the liquid ejection apparatus.

Japanese Patent Laid-Open No. 2003-211688 JP 2003-220711 A

  However, since the pressure damper mechanism and the pressure adjusting mechanism according to Patent Documents 1 and 2 have a liquid chamber (widened portion) widened with respect to a tubular flow channel such as a supply tube, structurally air ( Bubbles) are likely to stay. In particular, air tends to stay in the upper part of the widened portion, and the liquid cannot be completely filled in many cases. In order to prevent the accumulated air from flowing into the discharge head as bubbles, the communication port from the widened portion to the discharge head is provided at the bottom of the widened portion, but the bubbles flow out to the discharge head for some reason. There is still a danger, and it is hard to say that sufficient measures have been taken for ejection reliability.

  SUMMARY An advantage of some aspects of the invention is to provide a filling method for satisfactorily filling a liquid in a widened portion in a liquid ejection apparatus having a widened portion.

  The present invention includes a tubular flow channel for supplying a liquid from a liquid container to a discharge head, a widened portion that forms a flow channel that is widened in communication with the tubular flow channel, and the widened portion and the communication channel. A buffer unit configured to be variable in capacity according to a communication internal pressure, a filling method for filling the liquid into the liquid ejecting apparatus, the volume reducing step for reducing the capacity of the buffer unit, and An additional filling step of filling the widened portion with the liquid while recovering the volume of the buffer portion reduced in the volume reducing step.

  According to the filling method of the present invention, the buffer portion reduced by the capacity reduction step is expanded by the additional filling step, thereby generating a positive flow from the widened portion to the buffer portion, and this flow is transferred from the widened portion. By using this as a new exhaust path, it is possible to improve the liquid filling property to the widened portion.

The filling method may further include a preliminary filling step of filling the widened portion with the liquid without recovering the capacity of the buffer portion reduced in the capacity reducing step before the additional filling step. To do.
The liquid filling (additional filling step) using the exhaust path from the widened part to the buffer part is limited in time and exhaust amount depending on the capacity of the buffer part. It is desirable that it be planned. According to the filling method of the present invention, the normal filling (preliminary filling step) without using the exhaust path to the buffer portion is performed in advance, and the widened portion is filled with a certain amount of liquid, so that the additional filling step is excellent. Sex can be used effectively.

In the filling method, the capacity reduction step and the preliminary filling step are performed by decompressing the widened portion or the buffer portion by a suction operation of sucking the liquid or air from the nozzle of the ejection head. Features.
According to the filling method of the present invention, since the volume reduction step and the preliminary filling step are performed by a common method (suction from the nozzle), the liquid can be filled efficiently and with a simple hardware configuration.

In the filling method, the capacity reduction step is performed by the suction operation in a state where supply of the liquid from the liquid container to the widening portion is restricted.
When performing the above-described suction operation, the reduced pressure generated by the suction operation is compensated by the supply of the liquid from the liquid container side, so that it takes time and liquid to reach a predetermined pressure (degree of vacuum). It is also difficult to obtain a degree of vacuum sufficient to change the capacity. According to the filling method of the present invention, the decompression of the widened portion can be efficiently and effectively performed by performing the suction operation in a state where the supply of the liquid from the liquid container is restricted.

In the filling method, the preliminary filling step is performed in a state where the communication path is closed and the internal pressure of the buffer portion is maintained.
More preferably, in the filling method, the additional filling step is performed by opening the communication path in a state where the internal pressure of the widened portion is higher than the internal pressure maintained by the buffer portion.

According to the filling method of the present invention, since the communication path is closed and the internal pressure of the buffer portion is out of synchronization with the internal pressure of the widened portion, the suction operation conditions (suction speed, etc.) in the preliminary filling step are not affected. The internal pressure of the buffer unit is kept constant, and the capacity thereof is maintained in a reduced state. Thereby, it is possible to freely change the conditions of the suction operation in the preliminary filling step without being restricted by the capacity control of the buffer unit.
Preferably, if the additional filling step is performed from a state in which the internal pressure of the widened portion is higher than the internal pressure of the buffer portion, the exhaust from the widened portion to the buffer portion is vigorously performed in the additional filling step. Fillability can be further increased.

In the filling method, the additional filling step is performed while performing the suction operation.
According to the filling method of the present invention, it is possible to prevent the back flow of liquid from the discharge head side due to the fact that the supply of liquid to the widened portion is not in time in the process of exhausting from the widened portion to the pressure chamber. it can.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.
Note that the embodiments described below are preferred specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention is particularly limited in the following description. Unless otherwise stated, the present invention is not limited to these forms.

(Overall configuration of liquid ejection device)
First, the overall configuration of the liquid ejection device will be described with reference to FIG. FIG. 1 is a schematic plan view illustrating an example of a liquid ejection apparatus according to the present embodiment.

  A printer 10 as a liquid ejection apparatus includes frames 11a, 11b, and 11c that form an outer case of a casing, and a platen 16 in a region surrounded by the frames 11a to 11c. The platen 16 is provided for supporting a recording medium such as paper and landing ink as a liquid on the recording medium at the supported position. The recording medium is transported from the top to the bottom of the figure by a transport mechanism (not shown).

  A carriage 15 on which the ejection head 14 is mounted is provided at a position facing the platen 16. The carriage 15 is supported by a carriage guide shaft 12 connected to the inner surfaces of the frames 11a and 11c, and its movement is regulated. Power is transmitted via a belt 13 by a carriage drive motor 19, and the carriage guide shaft 12 can be moved back and forth. In this configuration, the ejection head 14 ejects ink while moving relative to the recording medium vertically and horizontally, whereby desired printing is performed.

  The printer 10 performs color printing by using several types of inks with different color materials, and uses, for example, four colors of ink of black, magenta, cyan, and yellow. These color inks are accommodated in ink cartridges 22a to 22d as detachable liquid containers, and are inserted into a cartridge holder 20 located on the right side of the drawing. The ink cartridges 22a to 22d are configured to include a bag-like container formed of a flexible film in a plastic case, for example.

  From the cartridge holder 20, supply pipes 18a to 18d configured to communicate with the ink cartridges 22a to 22d are drawn, and the discharge head 14 is supplied via the supply control mechanisms 30a to 30d and the pressure adjustment mechanisms 17a to 17d. To form a series of supply channels. The structures of the supply pipes 18a to 18d, the supply control mechanisms 30a to 30d, and the pressure adjustment mechanisms 17a to 17d corresponding to the inks of the respective colors are the same. The mechanism 30a and the pressure adjustment mechanism 17a are representatively performed.

  The printer 10 includes a pressurizing pump unit 28 on the upper surface of the cartridge holder 20, and pressurizes ink by sending pressurized air into the ink cartridges 22 a to 22 d through the vent pipes 21 a to 21 d and the cartridge holder 20. In this state, it can be supplied to the ejection head 14. The pressurizing pump unit 28 includes, for example, a diaphragm pump and a regulator for adjusting pressure.

  The printer 10 includes a maintenance unit 25 on the right side of the platen 16 in the drawing. In FIG. 1, a cap 26 and a wiper 24 are illustrated. The cap 26 is a member capable of sealing the ejection surface of the ejection head 14 and is used for maintenance of the ejection head 14 in an unused state and a suction operation described later. The wiper 24 is a plate-like member made of rubber or the like, and wipes ink or dirt adhering to the ejection surface by moving the carriage 15 while being in contact with the ejection surface of the ejection head 14. Used for.

(Configuration of supply system and waste liquid system)
Next, the configuration of the printer supply system and the waste liquid system will be described with reference to FIGS. FIG. 2 is a cross-sectional view schematically showing a part of the configuration relating to the supply system and the waste liquid system of the printer. FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2 showing the main configuration of the pressure adjusting mechanism.
2 and 3 illustrate that the vertical direction corresponds to the direction of gravity, and the shape and dimensional ratio of the flow path may be shown differently from the actual ones for convenience. is there.

  In FIG. 2, the flow path 32 of the supply control mechanism 30 a communicating with the supply pipe 18 a can be opened and closed by an on-off valve 31 serving as a supply restricting means. Specifically, for example, the flow path 32 can be formed. It is comprised so that a flexible tube may be crushed mechanically. The opening / closing operation of the opening / closing valve 31 is controlled by the control unit 35, and the supply of ink from the ink cartridge 22 a can be forcibly blocked by a command from the control unit 35.

The ink sent from the ink cartridge 22a via the supply control mechanism 30a is supplied to the ejection head 14 via the pressure adjustment mechanism 17a.
The pressure adjusting mechanism 17a is a combination of various mechanical components with a base material 50 made of synthetic resin or the like in which a flow path is formed. The pressure adjusting mechanism 17a communicates with the introduction path 251 through which ink is introduced from the supply pipe 18a. An introduction chamber 250, a pressure chamber 240 as a widened portion communicating with the introduction chamber 250 via the through hole 245, and a lead-out path 253 communicating with the discharge head 14. A pressure regulating valve 241 is provided between the introduction chamber 250 and the pressure chamber 240. The pressure regulating valve 241 performs a self-opening / closing operation according to the internal pressure of the pressure chamber 240, and keeps the internal pressure of the pressure chamber 240 constant. It is like that. In this configuration, the ink pressurized and supplied from the supply pipe 18 a is appropriately depressurized through the introduction path 251, the introduction chamber 250, and the pressure regulating valve 241, and is supplied from the pressure chamber 240 to the ejection head 14 through the outlet path 253. Will be.
The pressure adjustment mechanism 17 a is a branch chamber that communicates with the pressure chamber 240 via the communication path 52, and includes a buffer unit 61 that is configured to be variable in volume by the flexible container 60. The buffer unit 61 is provided to enhance the ink filling property in the pressure chamber 240, and the detailed configuration and function will be described later.

  The discharge head 14 includes an introduction path 41 that communicates with the pressure adjustment mechanism 17a, a reservoir 42 that temporarily stores ink, a cavity 44 that is branched from the reservoir 42 via a supply port 43, and each cavity. Nozzle 45 formed corresponding to 44. The cavity 44 is provided with pressure generating means (not shown) such as a piezoelectric element, and can eject ink from the nozzle 45 as droplets. By the way, in order to perform normal ejection, it is necessary to be in a so-called negative pressure state in which the ink hydraulic pressure in the cavity 44 is lower than the atmospheric pressure, and the pressure regulating valve 241 described above is in this negative pressure state. Is provided to generate

Here, with reference to FIG. 3, the principal part structure of the pressure regulation mechanism 17a which concerns on the pressure regulation valve 241 is demonstrated.
As shown in FIG. 3, the pressure adjustment mechanism 17 a includes a base material 50, films 248 and 249 that are welded to both surfaces of the base material 50, and a pressure receiving plate 254 that is bonded to the film 249. An introduction path 251, an introduction chamber 250, a pressure chamber 240, a through hole 245, a lead-out path 253, a communication path 52, and a communication port 51 are formed.

  The pressure adjustment valve 241 in the pressure adjustment mechanism 17a is configured as follows. That is, the pressure regulating valve 241 includes a valve body 255 including a shaft portion 255a inserted through the through hole 245 and a disc portion 255b formed on one end side of the shaft portion 255a. One surface of the disc portion 255b of the valve body 255 is in contact with one end of the spring 257, and the other end of the spring 257 is in contact with the spring seat 258. Then, as shown in the figure, the valve body 255 is urged to the right in the drawing by the elastic force of the compressed spring 257, and the other surface of the disk portion 255b presses the seal member 259 to introduce it into the introduction chamber 250. And communication between the pressure chamber 240 and the pressure chamber 240 are closed (closed state). The surface on the other end side of the shaft portion 255a of the valve body 255 faces the pressure receiving plate 254 through a film 249 as a flexible film.

  The pressure receiving plate 254 is movable in conjunction with the bending of the film 249. Here, when ink or the like is supplied from the outlet path 253 to the ejection head 14 and the internal pressure of the pressure chamber 240 decreases, the film 249 is bent inward, and the pressure receiving plate 254 moves in the direction of the arrow M. At this time, since the pressure receiving plate 254 receives a reaction force by the spring 260, the shaft portion 255a of the valve body 255 is not immediately pressed, but the pressure receiving plate 254 receives pressure as the differential pressure between the internal pressure of the pressure chamber 240 and the atmospheric pressure increases. The displacement amount of the plate 254 increases and eventually the valve body 255 starts to be pushed in the direction of the arrow M. When the pressure difference between the internal pressure of the pressure chamber 240 and the atmospheric pressure becomes larger than a predetermined value, the pressing force of the pressure receiving plate 254 overcomes the urging force of the spring 257, and the disc portion 255b is separated from the seal member 259 (open). Valve state). At this time, ink flows from the introduction chamber 250 into the pressure chamber 240 through the through hole 245, the internal pressure of the pressure chamber 240 is compensated, and the valve returns to the closed state again.

  Thus, the pressure chamber 240 is maintained in a constant negative pressure state by repeating the valve closing state, the internal pressure drop of the pressure chamber 240, the valve opening state, the internal pressure compensation of the pressure chamber 240, and the valve closing state. However, when the ink consumption speed is large due to a suction operation described later or when the ejection duty (imprinting amount per unit time) is remarkably increased, the pressure chamber 240 via the pressure adjustment valve 241 is used. The pressure chamber 240 may be depressurized to a pressure equal to or lower than the operating pressure of the pressure adjustment valve 241 because the ink is not supplied in time.

Returning to FIG. 2 again, a maintenance unit 25 as a suction means is provided at a position facing the ejection head 14, and is formed on a cap 26 capable of sealing the nozzle surface 46 and an inner bottom portion of the cap 26. And a suction pump 34 capable of depressurizing the internal space 29 of the cap 26 through a through hole 27 and a waste liquid tube 33 communicating with the through hole 27. The suction pump 34 is a tube pump, for example, and is driven and controlled by the control unit 35. Further, one end of the waste liquid tube 33 opposite to the cap 26 is connected to a waste liquid tank (not shown).
In this configuration, when the suction pump 34 is driven in a state where the cap 26 is in close contact with the nozzle surface 46 and the internal space 29 is sealed, ink (air when ink is not filled) is sucked and discharged from the nozzle 45, Ink continuously flows in a series of flow paths from the ink cartridge 22a to the nozzle 45. Such an operation of sucking ink or air from the nozzle 45 is hereinafter referred to as a suction operation.

  The suction operation includes an initial filling operation for initially filling the ink in the above-described supply system flow path (including the flow path in the ejection head 14) and a bubble that is mixed into the supply system flow path later. The refilling operation for refilling, the cleaning operation for removing the deteriorated ink in the nozzle 45, the re-formation of the meniscus, and the like are used. In each of these operations, the suction speed and the suction amount by the suction pump 34 are appropriately designed according to the purpose. For example, in the initial filling operation, since it is necessary to generate a large amount of ink flow and a large flow velocity, it is necessary to perform a large amount of suction at a high speed. On the other hand, in the cleaning operation, since the ink in the vicinity of the nozzle 45 needs to be sucked slightly, low speed and a small amount of suction may be used.

  In the initial filling operation and the refilling operation, ink filling is relatively easy in a tubular flow path such as the supply pipe 18a or the introduction path 251. However, in a flow channel (liquid chamber) that is widened like the pressure chamber 240, air stays in the upper portion of the liquid chamber due to the relationship between the positions of the introduction path 251 and the through hole 245 and the ink liquid level. It is easy to fill and ink filling is difficult. In view of such circumstances, the buffer unit 61 is provided in order to improve ink filling properties in the pressure chamber 240.

(Detailed description of buffer part)
Next, the configuration and function of the buffer unit will be described in detail with reference to FIG. 2, FIG. 4, and FIG. 4 is a cross-sectional view taken along the line B-B in FIG. 2 showing the main configuration of the pressure adjusting mechanism. FIG. 5 is a diagram illustrating the relationship between the internal pressure and the capacity of the buffer unit.
2 and 4, the flexible container 60 forming the buffer unit 61 is accommodated in a space 72 surrounded by a recess 70 formed in the base material 50 and a top plate 71 made of synthetic resin or the like. Yes. A through hole 73 is formed in the top plate 71, and the space 72 is opened to the atmosphere through the through hole 73.

  The flexible container 60 is formed in a bag shape with a flexible member such as a plastic film, and has a flat shape. One flat surface of the flexible container is bonded and fixed to the base material 50 to form a fixed surface 60a, and the other surface facing the fixed surface 60a is bonded and fixed to the pressure-receiving plate 65 of a plate-shaped member. The movable surface 60b is a pressure receiving means. A fold line 62 is formed on the side surface 60 c, and the flexible container 60 is configured to be foldable by the fold line 62. With these configurations, the movable surface 60b moves in the horizontal direction of the drawing, and the capacity of the buffer unit 61 can be changed with good reproducibility by the movement.

A cylindrical communication port member 63 is attached to the fixed surface 60 a of the flexible container 60, and a communication port 64 that communicates with the communication path 52 formed in the base material 50 and communicates with the buffer unit 61 is formed. ing. Further, the opening at the other end of the communication path 52 is formed in the upper part of the pressure chamber 240 and serves as a communication port 51. Thus, fluid (air or ink) can move between the buffer unit 61 and the pressure chamber 240 via the communication path 52.
The communication passage 52 is provided with an opening / closing valve 53 as communication passage opening / closing means configured in the same manner as the opening / closing valve 31 of the supply control mechanism 30a, and the control portion 35 can perform opening / closing control of the communication passage 52. . Thereby, the exchange of fluid between the buffer unit 61 and the pressure chamber 240 can be reliably controlled by the opening / closing control of the opening / closing valve 53. Further, by utilizing this opening / closing control, the internal pressure of the buffer unit 61 can be synchronized with the internal pressure of the pressure chamber 240 or can be maintained independently of the pressure chamber 240, and the internal pressure control of the buffer unit 61 can be freely performed. Increasing degree.

  A movable end 66 a of a constant load spring 66 as a restoring means is fixed to the pressure receiving plate 65, and a base portion 66 b of the constant load spring 66 is fixed to the top plate 71. The constant load spring 66 has a characteristic that the movable end 66a is hardly displaced until a load of a predetermined value or more, and the movable end 66a is largely displaced when the load exceeds the predetermined value.

  In the above-described configuration, in a steady state in which the buffer unit 61 is opened to the atmosphere, the flexible container 60 is in a sufficiently swollen state by the urging force of the constant load spring 66 (a large capacity state). When the internal pressure of the buffer unit 61 decreases, the movable surface 60b receives a leftward force due to the pressure difference between the inside and outside of the flexible container 60, and when the pressure difference exceeds a certain value, the constant load spring 66 moves. The end 66a extends, and the flexible container 60 is crushed small (small capacity state). FIG. 5 shows the capacity-internal pressure characteristics of the buffer section 61. As shown in the figure, the capacity of the buffer section 61 changes before and after the critical pressure Pc. FIG. 4 shows a transient state in which the flexible container 60 shifts from the large capacity state to the small capacity state.

  Returning to FIG. 2, when the buffer unit 61 changes from the small volume state to the large volume state, a fluid flow from the pressure chamber 240 to the buffer unit 61 through the communication path 52 is generated. By utilizing this positive flow as a new air discharge path (exhaust path) different from the discharge path from the outlet path 253, it is possible to improve the ink filling property in the pressure chamber 240. . That is, the buffer unit 61 functions as an air reservoir that sucks and stores air from the pressure chamber 240.

  When the communication path 52 is an exhaust path from the pressure chamber 240, the relationship between the position of the communication port 51 in the pressure chamber 240 and the ink level is important. That is, when the ink level in the pressure chamber 240 is higher than the position of the communication port 51, the communication port 51 cannot function as an air discharge port. Therefore, the position of the communication port 51 is preferably provided in consideration of this point, and in this embodiment, the communication port 51 is formed in the upper part of the pressure chamber 240. Further, the communication path 52 is formed to be inclined upward from the communication port 51 so that unnecessary ink does not easily flow from the pressure chamber 240 through the communication path 52 into the buffer unit 61.

  When the communication path 52 is used as an exhaust path from the pressure chamber 240, it is necessary to reduce the pressure of the buffer unit 61 to a small capacity prior to filling with ink. This decompression can be performed by a suction operation, and can be easily performed in combination with a series of procedures in the filling operation. Thus, from the state where the buffer unit 61 is in the small capacity state by the suction operation, the suction is stopped and the internal pressure of the buffer unit is recovered, so that air is supplied from the pressure chamber 240 to the buffer unit 61 via the communication path 52. As a result, the ink is satisfactorily filled in the pressure chamber 240.

On the other hand, it is desirable to maintain the capacity of the buffer unit 61 except during the filling operation. For example, when the capacity of the buffer unit 61 is reduced when the discharge duty is significantly increased, or when the internal pressure of the pressure chamber 240 is reduced due to low speed and a small amount of suction in the cleaning operation, air is supplied to the pressure chamber 240 through the communication path 52. This is because there is a possibility that it will be leaked again.
The buffer unit 61 in the present embodiment is configured so that the capacity hardly changes when the internal pressure is equal to or higher than the critical pressure Pc by using the constant load spring 66. Therefore, by appropriately designing the critical pressure Pc, as described above Responses to issues are being made.
In addition, since the printer 10 of the present embodiment includes the opening / closing valve 53 in the communication path 52, the above-described re-flow is prevented by always closing the opening / closing valve 53 of the communication path 52 except during the filling operation. Proactive banning is also possible.
Regarding the internal pressure-capacitance characteristics of the buffer unit 61 (see FIG. 5), the above-described correspondence configured using the constant load spring 66 is a weighting requirement for improving the ejection reliability in the printer 10. It is not an essential requirement of the invention. That is, in the present invention, the configuration of the buffer portion 61 using a linear spring instead of the constant load spring 66 is not denied.

(Filling operation)
Hereinafter, a specific flow of the filling operation will be described along the time axis of FIG. 6 with reference to FIG. FIG. 6 is a diagram illustrating the control timing of the control unit in the initial filling operation, and the change in the internal pressure of the pressure chamber and the capacity of the buffer unit.
As described above, the filling operation includes an initial filling operation in which the printer 10 in the unfilled state is initially filled with ink, and when bubbles are mixed into the flow path of the supply system later by replacing the ink cartridge 22a. In addition, there is a refilling operation for discharging such bubbles. Although both have a difference in parameters such as the suction amount, the main structure of the sequence is the same, and therefore, description will be made by using the initial filling operation as a representative.

  As shown in FIG. 6, in the initial stage (step S0 in FIG. 6), the on-off valve 53 and the on-off valve 31 are open, and the suction pump 34 is stopped. The pressure chamber 240 is open to the atmosphere via the nozzle 45, and the buffer unit 61 at this time is in a large capacity state.

  From the state of step S0, the cap 26 is brought into contact with the nozzle surface 46 of the discharge head 14, the on-off valve 31 is closed, and the suction pump 34 is driven at a high speed to start the suction operation. By this suction operation, the internal pressure of the pressure chamber 240 is greatly reduced as shown in FIG. 6 (step S1 in FIG. 6). The reason why the suction operation is performed in a state where the on-off valve 31 is closed is to increase the pressure reduction efficiency of the pressure chamber 240 by the suction operation. That is, when the suction operation is performed with the on-off valve 31 open, air or ink is continuously supplied to the pressure chamber 240 to compensate for the pressure drop, so that the pressure reduction to a certain level takes time. In addition, since a sufficient pressure (degree of vacuum) cannot be reached, the on-off valve 31 is closed to shut off the ink supply. Such a suction operation performed by restricting (chalking) the supply of ink from the ink cartridge 22a is particularly referred to as a choke suction operation.

  When the internal pressure of the pressure chamber 240, that is, the internal pressure of the buffer unit 61 reaches the critical pressure Pc (see FIG. 5), the capacity of the buffer unit 61 starts to decrease and changes from the large capacity state to the small capacity state (in FIG. 6). Capacity reduction step S2). The internal pressure of the pressure chamber 240 gradually approaches P1, which is the ultimate pressure in the choke suction operation. By this capacity reduction step S2, elastic energy for restoring the buffer section 61 to a large capacity state is stored in the constant load spring 66 constituting the buffer section 61.

  The capacity reduction step S2 can also be performed by a normal suction operation without using the choke suction operation as described above. In this case, since the ultimate pressure becomes larger than P1, it is necessary to set the critical pressure Pc for changing the capacity of the buffer 61 higher than that in the present embodiment in accordance with the capacity of the suction operation. In this case, however, it is difficult to keep the internal pressure of the buffer unit 61 (pressure chamber 240) sufficiently high from the critical pressure Pc during the non-filling operation (printing or cleaning operation). May also affect That is, in the present embodiment, the choke suction operation is performed in the capacity reduction step S2, so that the degree of freedom in designing the critical pressure Pc is increased, and as a result, the stability of the buffer unit 61 during the non-filling operation is improved. It is intended.

When the internal pressure of the pressure chamber 240 reaches P1, the on-off valve 53 is closed to stop pressure synchronization between the pressure chamber 240 and the buffer unit 61, and the on-off valve 31 is opened to open a series of flow paths in the pressure control mechanism 17a and the discharge head 14. Ink is allowed to flow into (preliminary filling step S3 in FIG. 6). In this preliminary filling step S 3, air is discharged from the pressure chamber 240 through the nozzle 45, and instead, the pressure chamber 240 is filled with ink through the introduction path 251 and the pressure adjustment valve 241.
In the preliminary filling step S3, since the communication passage 52 does not function as an exhaust path, the filling property in the pressure chamber 240 is the same as that of the conventional pressure adjusting mechanism 17a that does not have the buffer portion 61. That is, even if the suction operation is continued for a certain time or more, it is difficult to fill the ink above the through hole 245 and air remains in the upper portion of the pressure chamber 240. Therefore, the suction pump 34 is switched to low speed driving, and the amount of ink discharged from the nozzle 45 is suppressed. Thus, the internal pressure of the pressure chamber 240 gradually approaches P2, and the ink flow velocity in the flow path becomes gentle (step S4 in FIG. 6).

  In steps S3 and S4, since the internal pressure of the buffer unit 61 is asynchronous with the internal pressure of the pressure chamber 240 by closing the on-off valve 53, the internal pressure of the buffer unit 61 is maintained at P1, and its capacity is small. The capacity state will be maintained. Thereby, it is possible to freely change the driving condition of the suction pump 34 in steps S3 and S4 without being restricted by the capacity control of the buffer unit 61.

When the internal pressure of the pressure chamber 240 becomes P2 in step S4, the on-off valve 53 is opened to synchronize the internal pressure of the buffer unit 61 with the internal pressure of the pressure chamber 240, and the buffer unit 61 is changed from the small capacity state to the large capacity state. At this time, the air remaining in the upper portion of the pressure chamber 240 is discharged from the communication port 51, and ink filling of the pressure chamber 240 is performed (addition filling step S5 in FIG. 6).
When ink is satisfactorily filled in the pressure chamber 240 in the additional filling step S5, the suction pump 34 is stopped to stop the suction operation (step S6 in FIG. 6). The internal pressure of the pressure chamber 240 at this time is P3 (<atmospheric pressure) that is the operating pressure of the pressure regulating valve 241. Thereafter, a minute suction operation by the suction pump 34 and a wiping operation of the nozzle surface 46 by the wiper 24 (see FIG. 1) are appropriately performed, and the initial filling operation is completed.

  In this embodiment, the preliminary filling step S3 is performed prior to the additional filling step S5. The ink filling using the communication path 52 as the exhaust path (addition filling step S5) depends on the capacity of the buffer unit 61. In view of the limited time and displacement. That is, normal filling (preliminary filling step S3) using the outlet path 253 as an exhaust path is performed in advance, and the additional filling step S5 is performed after the pressure chamber 240 is filled with ink to some extent, so that the additional filling step S5 is superior. The filling properties can be effectively used. In other words, the preliminary filling step S3 is a weighting requirement provided not to affect the filling property itself of the additional filling step S5 but to appropriately use the additional filling step S5.

  In the filling operation of the present embodiment, when opening the on-off valve 53, the internal pressure P2 of the pressure chamber 240 is made higher than the internal pressure P1 of the buffer unit 61. Thereby, the exhaust from the pressure chamber 240 to the buffer unit 61 is performed vigorously, and the filling property of the pressure chamber 240 can be further improved. As described above, the opening / closing valve 53 is used in the additional filling step S5, and the internal pressure control between the pressure chamber 240 and the buffer unit 61 is made asynchronous in steps S3 and S4, so that the effect of the additional filling step S5 is enhanced. It is a thing.

In the filling operation of this embodiment, in the additional filling step S5, ink is filled into the pressure chamber 240 while the suction pump 34 is driven at a low speed to perform the suction operation. By doing this, in the process of exhausting from the pressure chamber 240 to the buffer unit 61, the backflow of ink from the ejection head 14 side due to the fact that the supply of ink through the pressure adjustment valve 241 is not in time is prevented. Can be prevented.
In view of such problems, it is desirable that the balance between the ink supply speed from the pressure adjustment valve 241 and the exhaust speed from the communication path 52 is taken into consideration in the design of the pressure adjustment mechanism 17a. For example, it is considered that an appropriate flow resistance (pressure loss) is generated depending on the shape of the communication passage 52, or that an appropriate load is applied to the reduction or expansion of the flexible container. It is done.

The present invention is not limited to the above-described embodiment.
For example, the buffer unit in the present invention may be configured using a rigid container and a piston-like movable wall member. Further, the buffer unit may be configured by using an elastic membrane that functions as a restoring means for generating a restoring force of the wall surface and also functions as a pressure receiving means for changing the capacity according to the internal pressure.
Moreover, the aspect of the widening part and buffer part in this invention is not limited to the above-mentioned embodiment applied about the pressure adjustment mechanism 17a. For example, the pressure damper mechanism according to Patent Document 1 also includes a widened portion that is widened in communication with the tubular flow path, and an aspect in which a buffer portion is configured for the widened portion is also included in the present invention. In addition, the present invention is applied to a liquid ejection apparatus having a similar flow path structure related to a supply system.
The on-off valve 53 that can open and close the communication passage 52 is not an essential requirement of the printer 10 in the present invention, and the filling operation can be performed without using the on-off valve 53. In this case, the capacity control of the buffer unit 61 is performed by changing the internal pressure of the pressure chamber 240 according to the suction speed of the suction operation.
Moreover, each structure of each embodiment can combine these suitably, can be abbreviate | omitted, or can be combined with the other structure which is not illustrated.

FIG. 3 is a schematic plan view illustrating an example of a liquid ejection apparatus according to the present embodiment. FIG. 3 is a cross-sectional view schematically showing a part of a configuration related to a printer supply system and a waste liquid system. The AA sectional view of Drawing 2 showing the important section composition of a pressure regulation mechanism. BB sectional drawing of FIG. 2 which shows the principal part structure of a pressure adjustment mechanism. The figure which shows the relationship between the internal pressure of a buffer part, and capacity | capacitance. The figure which shows the control timing of the control part in an initial filling operation | movement, and the change of the internal pressure of a pressure chamber, and the capacity | capacitance of a buffer part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Printer as a liquid discharge apparatus, 14 ... Discharge head, 15 ... Carriage, 17a-17d ... Pressure adjustment mechanism, 18a-18d ... Supply pipe | tube as a tubular flow path, 22a-22d ... Ink cartridge as a liquid container, 25 ... Maintenance unit as suction means, 26 ... Cap, 27 ... Through hole, 29 ... Internal space, 30a-30d ... Supply control mechanism, 31 ... Open / close valve as supply control means, 32 ... Flow as tubular flow path 33, waste liquid tube, 34 ... suction pump, 35 ... controller, 41 ... introduction path, 42 ... reservoir, 43 ... supply port, 44 ... cavity, 45 ... nozzle, 46 ... nozzle surface, 50 ... substrate, 51 ... Communication port, 52 ... Communication passage, 53 ... Open / close valve as communication passage opening / closing means, 60 ... Flexible container, 60a ... Fixed surface, 60b ... Moving surface as pressure receiving means, 0c ... side surface, 61 ... buffer portion, 62 ... fold, 63 ... communication port member, 64 ... communication port, 65 ... pressure receiving plate, 66 ... constant load spring as restoring means, 66a ... movable end, 66b ... base, 70 ... Recessed portion, 71 ... top plate, 72 ... space, 73 ... through hole, 240 ... pressure chamber as widened portion, 241 ... pressure adjusting valve, 245 ... through hole, 248 ... film, 249 ... film, 250 ... introducing chamber, 251 ... Introduction path as tubular flow path, 253 ... Derivation path as tubular flow path, 254 ... Pressure receiving plate, 255 ... Valve element, 255a ... Shaft portion, 255b ... Disk portion, 257 ... Spring, 258 ... Spring seat 259 ... sealing member, 260 ... spring.

Claims (7)

A tubular flow channel for supplying a liquid from the liquid container to the discharge head, a widened portion that forms a widened flow channel in communication with the tubular flow channel, and the internal pressure is communicated through the widened portion and the communication channel. A filling unit for filling the liquid into a liquid ejecting apparatus comprising a buffer unit configured to be variable in response,
A capacity reduction step for reducing the capacity of the buffer unit;
A filling method comprising: an additional filling step of filling the widened portion with the liquid while recovering the volume of the buffer portion reduced in the volume reducing step.   The pre-filling step of filling the widened portion with the liquid without recovering the capacity of the buffer portion reduced in the capacity reducing step before the additional filling step. Filling method.   3. The capacity reduction step and the preliminary filling step are performed by decompressing the widened portion or the buffer portion by a suction operation of sucking the liquid or air from the nozzle of the ejection head. The filling method as described.   The filling method according to claim 3, wherein the volume reduction step is performed by the suction operation in a state where supply of the liquid from the liquid container to the widening portion is restricted.   5. The filling method according to claim 3, wherein the preliminary filling step is performed in a state in which the communication path is closed and an internal pressure of the buffer unit is maintained.   6. The filling method according to claim 5, wherein the additional filling step is performed by opening the communication path in a state in which an internal pressure of the widened portion is higher than an internal pressure maintained in the buffer portion. The filling method according to claim 3, wherein the additional filling step is performed while performing the suction operation.

Images