JP2026012041A - Recording device - Google Patents

Abstract

When a container is replaced, it is possible to prevent air bubbles from entering a flow path and reduce productivity.
[Solution] The recording device comprises a liquid chamber into which liquid is introduced from a liquid container and which contains liquid to be supplied to an ejection means which ejects the liquid onto a recording medium, and a forming means which forms a pressure chamber adjacent to the liquid chamber; a wall which separates the liquid chamber from the pressure chamber and which changes the volume of the liquid chamber by displacing according to the pressure of the pressure chamber; a pressure adjustment means which adjusts the pressure of the pressure chamber to perform a refilling operation which introduces liquid from the liquid container into the liquid chamber and a supplying operation which supplies liquid from the liquid chamber to the ejection means; and an atmosphere opening means which opens the pressure chamber to the atmosphere in response to an operation related to replacing the liquid container during the refilling operation, but does not open the pressure chamber to the atmosphere for the operation during the supplying operation.
[Selected Figure] Figure 18

Description

The present invention relates to a recording device.

In recording devices that record images by ejecting ink from an ejection head, the ink containers that hold the ink are designed to be replaceable. When replacing the containers, problems such as leakage of the ink can occur, and recording devices that take measures to address this have been proposed (for example, see Patent Document 1).

Japanese Patent Application Laid-Open No. 2006-192793

In a recording device that has an intermediate liquid chamber between the ink reservoir and the ejection head, the volume of the liquid chamber can be increased or decreased by controlling the pressure around the liquid chamber, allowing ink to be introduced into the liquid chamber and pressurized and supplied from the liquid chamber to the ejection head. In a recording device with this configuration, if the reservoir is replaced while ink is being introduced into the liquid chamber, air bubbles may be sucked into the ink flow path. On the other hand, if pressure control is uniformly stopped when the reservoir is replaced, it may be necessary to halt recording operations while the reservoir is being replaced during pressurized supply, which could reduce productivity.

The present invention provides technology that can prevent air bubbles from entering the flow path and reduce productivity when the container is replaced.

According to the present invention,
a liquid chamber for receiving liquid from a liquid container and for storing the liquid to be supplied to a discharge means for discharging the liquid onto a recording medium, and a forming means for forming a pressure chamber adjacent to the liquid chamber;
a wall that separates the liquid chamber from the pressure chamber and that changes the volume of the liquid chamber by being displaced in response to the pressure of the pressure chamber;
a pressure adjusting means for adjusting the pressure of the pressure chamber to perform a replenishing operation of introducing liquid from the liquid container into the liquid chamber and a supplying operation of supplying liquid from the liquid chamber to the ejection means;
and an atmosphere opening means for opening the pressure chamber to the atmosphere in response to an operation related to replacement of the liquid container during the refilling operation, but not opening the pressure chamber to the atmosphere in response to the operation during the supplying operation.
A recording device is provided.

This invention provides technology that can prevent air bubbles from entering the flow path and reduce productivity when the container is replaced.

1A is an external view of a recording apparatus according to an embodiment of the present invention, and FIG. 1B is a view showing a state in which an access cover is open. FIG. 2 is an explanatory diagram of the internal mechanism of the recording apparatus of FIG. FIG. 4 is an explanatory diagram of a liquid supply unit from a container to a discharge head. FIG. 4 is an explanatory diagram showing the structure of an intermediate tank. FIG. 10 is an explanatory diagram of the operation of the intermediate tank. FIG. 10 is an explanatory diagram of the operation of the intermediate tank. FIG. 10 is an explanatory diagram of the remaining amount detection operation in the intermediate tank. FIG. 10 is an explanatory diagram of remaining amount determination for an intermediate tank. FIG. 4 is an explanatory diagram showing the structure of each check valve on the upstream and downstream sides of the intermediate tank. 5A and 5B are explanatory diagrams of the structure and operation of a negative pressure maintaining unit. FIG. FIG. 4 is a diagram showing the opening and closing patterns of each control valve of the pressure adjustment unit. FIG. 4 is an explanatory diagram of the operation of each control valve of the pressure adjustment unit. 3A and 3B are diagrams showing a specific structural example of a pressure adjustment unit. FIG. 3 is an explanatory diagram of the structure of a valve unit. FIG. (A) is an explanatory diagram of the atmospheric release unit, and (B) is an explanatory diagram of the operation of the interlocking valve. FIG. FIG. 4 is a block diagram of a control circuit of the supply unit of FIG. 3 ; 10 is a flowchart showing an example of processing by a control circuit. 10 is a flowchart showing an example of processing by a control circuit. 10 is a flowchart showing an example of processing by a control circuit. 10 is a flowchart showing an example of processing by a control circuit. 10 is a flowchart showing an example of processing by a control circuit. FIG. 10 is a block diagram of another example of a control circuit. 10 is a flowchart showing an example of processing by a control circuit. 10 is a flowchart showing an example of processing by a control circuit.

The following describes the embodiments in detail with reference to the attached drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although the embodiments describe multiple features, not all of these features are necessarily essential to the invention, and multiple features may be combined in any desired manner. Furthermore, in the attached drawings, the same reference numbers are used to designate identical or similar components, and redundant explanations will be omitted.

First Embodiment
<Outline of the recording device>
1A is an external view of a recording apparatus 1 according to one embodiment of the present invention, as seen from the front. The recording apparatus 1 of this embodiment is an inkjet recording apparatus that ejects ink as a liquid to record on a recording medium. In the figure, arrows X to Z indicate directions that intersect with each other, and in this embodiment in particular, arrows X and Y indicate horizontal directions that are orthogonal to each other, and arrow Z indicates the up-down direction (direction of gravity). The X direction is the width direction (left-right direction) of the recording apparatus 1. The Y direction is the depth direction of the recording apparatus 1.

Note that "recording" not only refers to the formation of meaningful information such as characters and figures, but also broadly includes the formation of images, designs, patterns, etc. on a recording medium, whether meaningful or insignificant, or the processing of the medium, regardless of whether it is manifested in a way that can be perceived visually by humans. Furthermore, in this embodiment, sheet-like paper is assumed as the "recording medium," but it can also be cloth, plastic film, etc.

The recording device 1 has an overall rectangular parallelepiped shape, with a foldable paper feed tray 2A provided at the rear of its top surface and a paper feed cassette 2B and discharge port 3 provided at its front. The paper feed tray 2A and paper feed cassette 2B form a loading section on which recording media are stacked before recording. The paper feed cassette 2B can be inserted and removed from the device body in the Y direction. After recording, the recording media is discharged from the discharge port 3. The discharge port 3 is provided with a discharge tray on which the recording media is placed after recording.

The front of the recording device 1 is provided with an operation unit 14 that can be operated by the user. The operation unit 14 is equipped with a display unit that displays information and multiple operation buttons, and can accept instructions input by the user and present information to the user. The display unit may be a touch panel.

Storage units 15A and 15B are provided at the front of the recording device 1. Storage units 15A and 15B are spaced apart in the X direction, with a paper feed cassette 2B and discharge port 3 provided between storage units 15A and 15B. Access covers 16A and 16B that open and close storage units 15A and 15B are provided on storage units 15A and 15B, respectively. When access covers 16A and 16B are opened, the interiors of storage units 15A and 15B are exposed.

Figure 1 (B) shows the state with access cover 16A open. Multiple containers 17 are stored in storage section 15A, and containers 17 are exposed when access cover 16A is opened. Containers 17 are liquid containers that store ink as a liquid. Containers 17 may be in the form of a rigid resin box or a flexible bag (pack). When access cover 16A is closed, containers 17 are covered by access cover 16A.

Each container 17 is a cartridge-type ink tank that can be inserted and removed in the Y direction. The user can replace the container 17 by opening the access cover 16A. In this embodiment, three containers 17 are stored in the storage section 15A. The three containers 17 contain different types of ink. For example, the three containers 17 contain yellow, magenta, and cyan inks.

Storage section 15B and access cover 16B are similar to storage section 15A and access cover 16B. However, in this embodiment, storage section 15B stores one container 17 (not shown). The container 17 stored in storage section 15B stores, for example, black ink. In this embodiment, a configuration in which storage sections are provided on the left and right sides is shown, but a configuration in which four color containers 17 are provided on one side, for example, at the position of storage section 15A, may also be used.

Figure 2 is an explanatory diagram showing the internal mechanism of the recording device 1. The recording medium P set in the paper feed tray 2A or paper feed cassette 2B is transported by the transport unit 4A or 4B and transport units 5-8, guided by the guide member 9. During the transport process, an image is recorded by the ejection head 11, and the recording medium is discharged through the discharge port 3. The guide member 9 has a guide portion 9a that forms a path for turning the recording medium P over, and the recording device 1 is also capable of double-sided recording on the recording medium P.

Of transport units 4A and 4B and transport units 5-8, transport units 4A and 4B are located furthest upstream in the transport direction of recording medium P. Transport unit 5 is located downstream of transport unit 4B, and transport unit 6 is located downstream of transport units 4A and 5. Transport unit 7 is located downstream of transport unit 6, and transport unit 8 is located downstream of transport unit 7.

The transport unit 7 transports the recording medium P in the Y direction (sub-scanning direction) relative to the ejection head 11. The image recording position in the Y direction relative to the recording medium P is controlled by driving and controlling the transport unit 7. The transport unit 7 includes a drive roller 7a and a driven roller 7b that is in pressure contact with the drive roller 7a, and these rollers clamp and transport the recording medium P.

Transport units 4A and 4B and transport units 5 and 6 can also be called feeding units because they feed recording medium P to transport unit 7. In this embodiment, transport units 4A and 4B are equipped with pickup rollers that pick up recording medium P from the corresponding paper feed tray 2A or paper feed cassette 2B and transport it to transport unit 5 or 6.

Transport units 5 and 6 include drive rollers 5a and 6a and driven rollers 5b and 6b that press against the corresponding drive rollers 5a and 6a, and these rollers sandwich and transport the recording medium P. Transport units 5 and 6 can also be called intermediate units or intermediate rollers because they are located between the most upstream transport units 4A and 4B and transport unit 7.

The transport unit 8 can also be called a discharge unit because it discharges the recorded recording medium P to the discharge port 3. The transport unit 8 includes a drive roller 8a and a driven roller 7b that is in pressure contact with the drive roller 8a, and these rollers clamp and transport the recording medium P.

The ejection head 11 is a recording head that ejects ink to record on a recording medium. The ejection head 11 is positioned between the transport unit 7 and the transport unit 8 in the transport direction of the recording medium P. The ejection head 11 is mounted on a carriage 12. The ejection port surface (bottom surface) of the ejection head 11 faces the platen 10, and ejects liquid from multiple nozzles formed on the ink ejection surface onto the recording medium P being transported over the platen 10. A separate ejection head 11 is provided for each type of liquid.

The carriage 12 is moved back and forth across the recording medium P (in this embodiment, the X direction, the main scanning direction) by the drive unit 13. The drive unit 13 is a belt transmission mechanism driven by a motor, and includes, for example, a drive pulley and a driven pulley spaced apart in the X direction, an endless belt wound around these pulleys, and a guide member that guides the movement of the carriage 12 in the X direction. The carriage 12 is connected to the endless belt. When the drive pulley is rotated by the motor, the endless belt runs and the carriage 12 moves. The ejection head 11 may be replaceably attached to the carriage 12.

As such, the recording device 1 of this embodiment is a serial type recording device in which the ejection head 11 is mounted on the carriage 12. The recording operation on the recording medium P is performed by the transport unit 7 by alternately repeating a transport operation (intermittent transport operation) that transports the recording medium P a predetermined amount and a recording scan while transport of the transport unit 7 is stopped. The recording scan is an operation in which ink is ejected from the ejection head 11 while the carriage 12 carrying the ejection head 11 is moved. Note that the ejection head 11 may also be a full-line recording head extended in the X direction.

<Liquid supply system>
Next, a description will be given of a supply unit for supplying liquid from the container 17 to the ejection head 11. FIG.

The supply unit 18 is a supply mechanism that supplies liquid from the container 17 to the ejection head 11. A supply unit 18 is provided for each container 17. Therefore, the recording device 1 of this embodiment has four supply units 18. Figure 3 illustrates one of the four supply units 18.

The supply unit 18 includes an intermediate tank 20, backflow prevention valves 30 and 40, a negative pressure maintenance unit 50, a pressure adjustment unit 60, and an atmospheric release unit 80 (Figure 11). The intermediate tank 20 is connected to the container 17 via pipe 19a, backflow prevention valve 30, and pipe 19b. The negative pressure maintenance unit 50 is connected to the intermediate tank 20 via pipe 19c, backflow prevention valve 40, and pipe 19d.

The pressure adjustment unit 60 is connected to the intermediate tank 20 via pipe 19e. Pipe 19e forms a flow path for the pressure control fluid. In this embodiment, the fluid is a gas, particularly air. Pipe 19f forms an atmosphere communication path that communicates with the atmosphere. The atmosphere release unit 80 is connected to the intermediate tank 20 via pipe 19e. Pipes 19a to 19f are, for example, flexible tubes. Pipes 19a to 19d may be made of a material with low gas permeability or water vapor permeability to prevent deterioration of the liquid flowing through them. Pipes 19a to 19f do not necessarily have to be flexible tubes; at least some of them may be metal pipes, or a flow path may be formed by tightly sealing a groove formed in a plate-shaped part with another part.

The liquid in the container 17 is introduced into the intermediate tank 20 via pipe 19a, check valve 30, and pipe 19b. In the direction of liquid introduction, the container 17 is located upstream, and the intermediate tank 20 is located downstream. The check valve 30 is located upstream of the intermediate tank 20 and is a one-way valve (check valve) that prevents liquid from flowing back from the intermediate tank 20 to the container 17.

The liquid in the intermediate tank 20 is supplied to the ejection head 11 via pipe 19c, backflow prevention valve 40, pipe 19d, and negative pressure maintenance unit 50. In the liquid supply direction, the intermediate tank 20 is located upstream, and the ejection head 11 is located downstream. The backflow prevention valve 40 is located downstream of the intermediate tank 20, and is a one-way valve (check valve) that prevents liquid from flowing back from the negative pressure maintenance unit 50 side to the intermediate tank 20 side.

In this embodiment, the liquid is replenished from the container 17 to the intermediate tank 20 using pressure generated by the pressure adjustment unit 60, so the liquid pressure inside the container 17 only needs to be close to atmospheric pressure, and there are few layout restrictions. Furthermore, because the liquid is supplied to the ejection head 11 using a pressurized system, there are few restrictions on the installation location of each component, and the intermediate tank 20 and the ejection head 11 can be installed in a location where there is a head difference between them.

(Intermediate tank)
The configuration of the intermediate tank 20 will be described with reference to Figures 3 and 4. Figure 4 is an explanatory diagram showing the structure of the intermediate tank 20. The intermediate tank 20 performs an introduction operation of introducing the liquid contained in the container 17 by suction, and a supply operation of sending the introduced liquid toward the ejection head 11. The introduction operation can also be called a liquid replenishment operation. In terms of these two operations, the intermediate tank 20 plays the role of a pump.

The intermediate tank 20 includes a forming unit 21 that forms the liquid chamber 20a and the pressure chamber 20b. The forming unit 21 is a hollow body that forms the outer walls that define the liquid chamber 20a and the pressure chamber 20b. In this embodiment, the forming unit 21 includes a cup-shaped housing 21A and a lid member 21B that covers the opening at the top of the housing 21A.

The liquid chamber 20a contains the liquid L to be supplied to the ejection head 11. The liquid L is introduced into the liquid chamber 20a from the container 17. The cover member 21B has an inlet pipe 21a that forms an inlet communicating with the liquid chamber 20a, and an outlet pipe 21b that forms an outlet communicating with the liquid chamber 20a. The inlet pipe 21a is connected to the pipe 19b, and the outlet pipe 21b is connected to the pipe 19c.

The pressure chamber 20b is formed adjacent to the liquid chamber 20a via a wall 22. The wall 22 separates the liquid chamber 20a from the pressure chamber 20b. The wall 22 can also be considered part of the peripheral wall that defines the liquid chamber 20a and the pressure chamber 20b. The wall 22 is a diaphragm that changes the volume of the liquid chamber 20a by displacing in response to the pressure in the pressure chamber 20b. In this embodiment, the wall 22 is made of a flexible sheet that elastically deforms in response to the pressure difference between the liquid chamber 20a and the pressure chamber 20b, and has a ring-shaped convex portion formed on its periphery.

The wall body 22 is airtightly sandwiched between the cover member 21B and the frame body 23. The frame body 23 is an annular member with an opening 23a in its center. The frame body 23 is supported by multiple shaft members 28 erected on the bottom of the housing 21A. The periphery of the wall body 22 is sandwiched between the cover member 21B and the frame body 23, and the center of the wall body 22 can be displaced below the opening 23a.

The housing 21A has a communication pipe 21c that forms a communication passage that connects the pressure adjustment unit 60 and the pressure chamber 20b. The piping 19e is connected to the communication pipe 21c. The pressure chamber 20b is provided with a restriction unit 25 that restricts the displacement of the wall 22 in accordance with the pressure in the pressure chamber 20b. The restriction unit 25 restricts the maximum displacement position of the wall 22 in the direction in which the liquid chamber 20a increases.

The restriction unit 25 includes a stopper 27 and a flexible member 26. The flexible member 26 forms a partition wall for the air chamber 20c in the pressure chamber 20b. In other words, the pressure chamber 20b is partitioned by the flexible member 26 into a bottom-side air chamber 20c portion and a liquid chamber 20a portion. The flexible member 26 is a diaphragm that changes the volume of the air chamber 20c by displacing in response to the pressure in the pressure chamber 20b. In this embodiment, the wall 22 is made of a flexible film that elastically deforms in response to the pressure difference between the liquid chamber 20a and the pressure chamber 20b, and its periphery is airtightly attached to the bottom of the housing 21A.

The housing 21A has a communication pipe 21d that forms an atmosphere communication port at its bottom. The communication pipe 21d is always open, and the air chamber 20c is maintained at atmospheric pressure. The stopper 27 has a hole (not shown) through which the shaft member 28 passes. It is a lifting member that is movable up and down in direction D1 (depth direction of the housing 21A) using the shaft member 28 as a guide axis and is displaced by the displacement of the flexible member 26. In this embodiment, the flexible member 26 is disposed between the stopper 27 and the bottom of the housing 21A. When the pressure chamber 20b becomes negative pressure, the flexible member 26 displaces upward to increase the volume of the air chamber 20c, causing the stopper 27 to rise to a restriction position that restricts the maximum displacement position. The stopper 27 has a recess 27a into which the abutment member 24 enters.

Abutment member 24 is fixed to the underside of the central portion of wall body 22. The abutment member 24 displaces along with the displacement of wall body 22. The abutment member 24 has an engagement groove 24a that engages with the end 70a of the detection lever 70. In this embodiment, the abutment member 24 abuts against a stopper 27, thereby restricting the displacement range of the wall body 22. It is also possible to restrict the displacement range of wall body 22 by directly abutting the wall body 22 and flexible member 26. However, by using the abutment member 24 and stopper 27, deterioration of the wall body 22 and flexible member 26 can be prevented, and the displacement range can be more accurately restricted.

A number of elastic members 29 are provided between the abutment member 24 and the stopper 27. In this embodiment, the elastic members 29 are coil springs through which the shaft member 28 is inserted, and urge the abutment member 24 and the stopper 27 in a direction separating them. In the state shown in Figure 4, the abutment member 24 and the stopper 27 are separated, and the displacement range of the wall body 22 is not restricted.

The detection lever 70 is a movable member for detecting the remaining amount of liquid in the liquid chamber 20a. The detection lever 70 has its middle portion 70b passing through the axial hole 21e and is rotatably supported in the axial hole 21e. The abutment member 24 is displaced in the direction D1 depending on the amount of liquid remaining in the liquid chamber 20a. The detection lever 70 rotates in the direction D2 due to the displacement of the abutment member 24. The amount of rotation of the detection lever 70 is detected by remaining amount detection sensors 71 and 72 located inside the housing 21A. The remaining amount of liquid in the liquid chamber 20a can be estimated based on the detection results of the remaining amount detection sensors 71 and 72. The detection lever 70 is constantly biased counterclockwise in FIG. 4 by an elastic member (not shown). Alternatively, the detection lever 70 may have its middle portion 70b extending outside the housing 21A through the axial hole 21e formed in the housing 21A. In this case, it may be configured to be rotatably supported in an airtightly sealed shaft hole 21e.

The operation of the intermediate tank 20 will be explained with reference to Figures 5 and 6 in addition to Figure 4. Figures 5 and 6 show the operation of each part of the intermediate tank 20, along with the internal pressure state.

State ST51 in Figure 5 shows a state in which the liquid L in the liquid chamber 20a has been almost depleted by the supply operation, and the volume of the liquid chamber 20a is at its minimum. The pressure chamber 20b is placed in a positive pressure state by the pressure adjustment unit 60. The air chamber 20c has almost no volume, and the stopper 27 is located at the position closest to the bottom of the housing 21A. Conversely, the abutment member 24 is located at the position closest to the liquid chamber 20a. From this point, the refilling operation is performed. Note that it is not necessary to wait until the remaining amount in the liquid chamber 20a has decreased to the state ST51 before performing the refilling operation; for example, the refilling operation may be performed when the remaining amount is around 50%.

State ST52 in Figure 5 shows the stage when the refilling operation has begun and the pressure adjustment unit 60 has placed the pressure chamber 20b in a negative pressure state. By placing the pressure chamber 20b in a negative pressure state, the wall 22 and the abutment member 24 are displaced toward the bottom of the housing 21A. The volume of the liquid chamber 20a increases, and liquid L is sucked into the liquid chamber 20a from the container 17. In state ST52, approximately 50% of the maximum capacity of the liquid chamber 20a has been introduced into the liquid chamber 20a.

In state ST52 in Figure 5, the flexible member 26 and stopper 27 are displaced in the opposite direction to the wall 22 (toward the lid member 21B), and air is sucked into the air chamber 20c, increasing its volume. In this embodiment, when the pressure chamber 20b is placed in a negative pressure state, the flexible member 26 is configured to displace before the wall 22. A viscous liquid flows into the liquid chamber 20a. On the other hand, air, which has less flow resistance than liquid, flows into the air chamber 20c. The inner diameter and length of the communicating tube 21d can also be designed to create almost no flow resistance. In this way, the flexible member 26 can be quickly deformed. This allows the flexible member 26 to displace before the wall 22, i.e., the displacement range of the wall 22 can be restricted.

The stopper 27 moves parallel to the liquid chamber 20a, guided by multiple shaft members 28. The stopper 27 moves against the biasing force of the elastic member 29. The stopper 27 moves until it abuts a protrusion (not shown) formed on the shaft members 28. This position becomes the restriction position that restricts the displacement range of the wall body 22. Note that the stopper 27 does not have to be configured to stop its movement at a predetermined position on the shaft members 28.

State ST53 in Figure 5 shows the stage where more liquid L has flowed into the liquid chamber 20a. The pressure chamber 20b remains in a negative pressure state, and the wall 22 displaces in a direction that increases the volume of the liquid chamber 20a, deforming and expanding. The abutment member 24 abuts against the stopper 27, restricting the displacement of the wall 22.

If the projected areas of the wall 22 and the flexible member 26 on a horizontal plane (a plane perpendicular to the direction D1 in FIG. 4) are S1 and S2, then:
S1 < S2
The shape is designed so that, under the same negative pressure NP,
|NP|×S1 < |NP|×S2
The force tending to expand the flexible member 26 is stronger than the force tending to expand the wall body 22. Therefore, the abutment of the abutting member 24 with the stopper 27 reliably restricts the displacement of the wall body 22.

State ST61 in Figure 6 shows a state in which negative pressure continues to act on the wall 22 from state ST53 in Figure 5. Due to the restriction of the stopper 27, the abutment member 24 cannot move further toward the stopper 27, so further elastic deformation occurs in a portion of the wall 22 (a thin portion such as portion A in the figure). The deformation then stops when the force due to the negative pressure in the pressure chamber 20b and the elastic deformation force of portion A of the wall 22 are balanced. A slight excess of liquid L flows into the liquid chamber 20a by the amount of deformation of portion A. In other words, the volume of the liquid chamber 20a in state ST61 is the maximum volume during the refilling operation, and this maximum volume is limited by the restriction unit 25.

State ST62 in Figure 6 shows the state where the refilling operation has ended and the supply operation has begun. The pressure adjustment unit 60 releases the negative pressure in the pressure chamber 20b, and it is then brought to a positive pressure state via atmospheric pressure. Air is exhausted from the air chamber 20c via the communicating tube 21, and the flexible member 26 collapses and displaces toward the communicating tube 21d. As the flexible member 26 displaces, the stopper 27 is also displaced toward the communicating tube 21d due to the bias of the elastic member 29, and the restriction on the displacement range of the wall body 22 is released.

When the restriction on the displacement range of the wall body 22 is released, the constraint on section A of the wall body 22 shown in state ST61 is released, and it attempts to return to its original shape. Because a small amount of excess liquid L equivalent to the deformation of section A has already flowed into the liquid chamber 20a, the abutment member 24 is displaced toward the stopper 27 by that amount. As a result, the pressure within the liquid chamber 20a becomes approximately equal to the pressure within the pressure chamber 20b, and when the liquid L in the liquid chamber 20a is pressurized and supplied toward the ejection head 11, no elastic deformation force equivalent to the deformation of section A of the wall body 22 acts.

This point will be explained in more detail. Let's assume that the restriction unit 25 is not provided, and during the refilling operation, the wall 22 abuts against a portion where the displacement restriction cannot be released (for example, the inner wall of the pressure chamber 20b), causing further elastic deformation of a portion of the wall 22, such as portion A. In this state, if the pressure chamber 20b is changed from a negative pressure state to a positive pressure state, the pressure of the liquid L in the liquid chamber 20a will increase due to the restoring force of the portion of the wall 22, such as portion A, that is elastically deformed. As a result, the liquid L will be supplied with a force stronger than the pressure assumed by the control of the pressure adjustment unit 60, which may cause the flow of the liquid L on the ejection head 11 side to become unstable.

In contrast, in this embodiment, when the pressure chamber 20b is in a negative pressure state, the restriction unit 25 restricts the displacement of the wall 22, and when the negative pressure state is released, the restriction on the displacement of the wall 22 is also released, and partial elastic deformation of the wall 22 is eliminated. This prevents the pressure of the liquid L in the liquid chamber 20a from increasing due to partial elastic deformation of the wall 22. As a result, the supply pressure of the liquid L supplied from the liquid chamber 20a to the ejection head can be more accurately controlled by the pressure adjustment unit 60, and variation in the supply pressure can be reduced.

Furthermore, if this excessive elastic deformation of a portion of the wall 22 is detected and the negative pressure in the pressure chamber 20b is released before this occurs, excess liquid L can be prevented from flowing into the liquid chamber 20a. However, it is not easy to detect the stage immediately before excessive elastic deformation of a portion of the wall 22, and an additional sensor or the like would be required. In contrast, this embodiment is advantageous in terms of cost and device layout.

At state ST62, the pressure state of pressure chamber 20b becomes positive, and the pressure of liquid L in liquid chamber 20a becomes approximately equal to the air pressure in pressure chamber 20b. State ST63 in Figure 6 shows a state in which the volume of liquid chamber 20a has contracted, and liquid L is being supplied from liquid chamber 20a to the ejection head 11 side. State ST63 shows a state in which approximately 50% of the maximum capacity of liquid chamber 20a has been supplied to the ejection head 11 side. Whether liquid is actually transported depends on the state of the negative pressure maintenance unit 50, which will be discussed later. As the supply of liquid L progresses, state ST51 in Figure 5 is reached, and the same operation is repeated.

(Detection of remaining amount)
Detection of the remaining amount of liquid L in the liquid chamber 20a will be described with reference to Figure 7. Figure 7 is an explanatory diagram of the remaining amount detection operation in the intermediate tank 20. As described above, rotation of the detection lever 70 is detected by the remaining amount detection sensors 71 and 72 disposed inside the housing 21A. To make the detection operation easier to understand, Figure 7 is a diagram in which the remaining amount detection sensors 71 and 72 and the detection lever 70 are added to the diagrams of the operation of the internal configuration of the intermediate tank 20 shown in Figures 5 and 6.

The detection lever 70 includes a detection piece 70c. The detection piece 70c is an internal part of the housing 21A. In this embodiment, the remaining amount detection sensors 71 and 72 are optical sensors, such as photointerrupters. The remaining amount detection sensors 71 and 72 are positioned at different positions on the rotational trajectory of the detection piece 70c, and the detection piece 70c functions as a shielding plate that blocks the optical axes of the remaining amount detection sensors 71 and 72. The detection piece 70c may also be an external part of the housing 21A. In this case, a portion of the detection lever 70 can be configured to be laid out outside the housing 21A, and the remaining amount detection sensors 71 and 72 can also be positioned outside the housing 21A. The wiring of the remaining amount detection sensors 71 and 72 can be hermetically sealed and extended outside the housing 21A.

State ST71 in Figure 7 shows the state in which the liquid chamber 20a has been refilled with 100% of its maximum volume of liquid L. In this state, the detection piece 70c is positioned away from both the remaining amount detection sensors 71 and 72 and is not detected.

State ST72 in Figure 7 shows a state in which liquid L has flowed out of the liquid chamber 20a and the remaining amount is 60% of its maximum volume. In this state, the detection piece 70c is detected by the remaining amount detection sensor 71, but is not detected by the remaining amount detection sensor 72.

State ST73 in Figure 7 shows a state in which liquid L has further flowed out of the liquid chamber 20a, and the remaining amount is 40% of its maximum volume. In this state, the detection piece 70c is detected by both the remaining amount detection sensors 71 and 72.

State ST74 in Figure 7 shows a state in which liquid L has further flowed out of the liquid chamber 20a, and the remaining amount is 10% or less of the maximum volume. In this state, the detection piece 70c is not detected by the remaining amount detection sensor 71, but is detected by the remaining amount detection sensor 72.

Figure 8 is an explanatory diagram of determining the remaining amount of liquid L in the liquid chamber 20a. In this embodiment, the estimated remaining amount of liquid L is divided into regions I to IV. Region I corresponds to a remaining amount of 60% to 100%, region II corresponds to a remaining amount of 40% to 60%, region III corresponds to a remaining amount of 10% to 40%, and region IV corresponds to a remaining amount of 10% or less.

Each region is defined by a threshold value corresponding to the rotational position of the detection lever 70. Region I and Region II are distinguished by the threshold value Low. The threshold value Low corresponds to the rotational position of the detection lever 70 when the detection result of the remaining amount detection sensor 71 is detection and the detection result of the remaining amount detection sensor 72 is non-detection. Region II and Region III are distinguished by the threshold value Out. The threshold value Out corresponds to the rotational position of the detection lever 70 when the detection result of the remaining amount detection sensors 71 and 72 are both detection. Region III and Region IV are distinguished by the threshold value Empty. The threshold value Empty corresponds to the rotational position of the detection lever 70 when the detection result of the remaining amount detection sensor 71 is non-detection and the detection result of the remaining amount detection sensor 72 is detection.

Areas I to IV can be identified from the detection results of the remaining amount detection sensors 71 and 72, and switching between replenishment and supply operations can be performed. The remaining amount of liquid L can also be estimated by using the amount of liquid L ejected from the ejection head 11 in combination. In this case, the number of dots of liquid L ejected from the ejection head 11 can be counted and accumulated, and then multiplied by the average ejection amount per dot to calculate an approximate value for the amount of liquid consumed (so-called dot count). By using dot count in combination, the remaining amount can be estimated more precisely than the four areas I to IV.

(Backflow prevention valve)
The structure of the check valves 30 and 40 will be described with reference to Fig. 9. Fig. 9 is an explanatory diagram of the structure of the check valves 30 and 40.

The check valve 30 comprises an upper housing member 31, a lower housing member 32, and a diaphragm 33 sandwiched between them. The diaphragm 33 is a flexible membrane molded from rubber or elastomer resin. The housing member 32 has an inlet pipe 32a forming an inlet for the liquid L and an outlet pipe 32b forming an outlet. Pipe 19a is connected to the inlet pipe 32a, and pipe 19b is connected to the outlet pipe 32b. A communication passage 30a for the liquid L, which communicates with the outlet, is formed between the housing members 31 and 32. The diaphragm 33 has a through-hole 33a through which the liquid L passes. The diaphragm 33 is positioned between the communication passage 30a and the inlet pipe 32a and is pressed against the housing member 32 by a coil spring 34, blocking communication between the communication passage 30a and the inlet pipe 32a.

The check valve 30 operates as a so-called differential pressure valve. When the pressure in the inlet pipe 32a and the pressure in the outlet pipe 32b are equal, the coil spring 34 presses the diaphragm 33 against the housing member 32, as shown in Figure 9, blocking the communication between the communication passage 30a and the inlet pipe 32a. In other words, the flow path of the fluid L is blocked. Similarly, when the pressure in the inlet pipe 32a is lower than the pressure in the outlet pipe 32b, the flow path of the fluid L is blocked.

On the other hand, when the pressure in the inlet pipe 32a is higher than the pressure in the outlet pipe 32b, the diaphragm 33 is lifted from the housing member 32 near the through-hole 33a, and the inlet pipe 32a and the outlet pipe 32b communicate with each other via the through-hole 33a and the communication passage 30a. In other words, the flow path for the fluid L is opened.

As a result of the above action, when the liquid chamber 20a of the intermediate tank 20 becomes negative pressure, the backflow prevention valve 30 opens and liquid L is sucked from the container 17 into the liquid chamber 20a. Conversely, when the liquid chamber 20a of the intermediate tank 20 becomes positive pressure, the backflow prevention valve 30 closes, preventing liquid L from flowing back from the liquid chamber 20a to the container 17.

The check valve 40 comprises an upper housing member 41, a lower housing member 42, and a diaphragm 43 sandwiched between them. The diaphragm 43 is a flexible membrane molded from rubber or elastomer resin. The housing member 42 has an inlet pipe 42a forming an inlet for the liquid L and an outlet pipe 42b forming an outlet. Pipe 19c is connected to the inlet pipe 42a, and pipe 19d is connected to the outlet pipe 42b. A communication passage 40a for the liquid L, which communicates with the outlet, is formed between the housing members 41 and 42. The diaphragm 43 has a portion that blocks the outlet pipe 42b, and this portion is pressed toward the housing member 42 by a coil spring 44 via a pressure plate 45, blocking the communication passage 40a and the outlet pipe 42b.

The check valve 40 also functions as a so-called differential pressure valve. When the pressure in the inlet pipe 42a and the pressure in the outlet pipe 42b are equal, the coil spring 34 presses the diaphragm 43 toward the housing member 42, as shown in Figure 9, blocking the communication between the communication passage 40a and the outlet pipe 42b. In other words, the flow path of fluid L is blocked. Similarly, when the pressure in the inlet pipe 42a is lower than the pressure in the outlet pipe 42b, the flow path of fluid L is blocked.

On the other hand, when the pressure in the inlet pipe 42a is higher than the pressure in the outlet pipe 42b, the diaphragm 43 is lifted, and the inlet pipe 42a and the outlet pipe 42b are connected via the communication passage 40a. In other words, the flow path for the fluid L is opened.

As a result of the above action, when the liquid chamber 20a of the intermediate tank 20 becomes positive pressure, the backflow prevention valve 40 opens and liquid L is supplied from the liquid chamber 20a to the ejection head 11 side. Conversely, when the liquid chamber 20a of the intermediate tank 20 becomes negative pressure, the backflow prevention valve 40 closes, preventing liquid L from flowing back from the ejection head 11 side to the liquid chamber 20a.

It is also possible to carry out a process known as a suction operation, in which a negative pressure is applied to the nozzle portion of the ejection head 11 using a negative pressure pump (not shown). In this case, the pressure chamber 20b is set to atmospheric pressure, and the liquid chamber 20a is set to atmospheric pressure. In other words, this process is carried out with the pressure inside the inlet pipe 42a at approximately atmospheric pressure. By then placing positive pressure in the pressure chamber 20b, the backflow prevention valve 40 is opened, and the liquid L can be sent at a high flow rate from the liquid chamber 20a to the ejection head 11 in one go.

(Negative pressure maintenance unit)
The structure and operation of the negative pressure maintenance unit 50 will be described with reference to Fig. 10. Fig. 10 is an explanatory diagram of the structure and operation of the negative pressure maintenance unit 50. State ST101 indicates a state in which the amount of stored liquid L is large, and state ST102 indicates a state in which the amount of stored liquid L is small.

The negative pressure maintenance unit 50 comprises a housing 51 in which the ejection head 11 is mounted, and constitutes an ejection head module. The housing 51 has an inlet pipe 51a that forms an inlet through which the liquid L supplied from the intermediate tank 20 flows, and a flow path 51b that communicates with the inlet pipe 51a. The inlet pipe 51a is connected to the piping 19d. A filter 53 is provided in the flow path 51b, and unwanted impurities are removed from the liquid L that flows into the flow path 51b as it passes through the filter 53.

The housing 51 also has flow paths 51c and 51e and a reservoir 50a. A portion of the peripheral wall of the reservoir 50a is formed by a diaphragm 52. The reservoir 50a is located between the liquid chamber 20a of the intermediate tank 20 and the ejection head, and is connected to the ejection head 11 via the flow path 51e. The reservoir 50a is a liquid chamber that temporarily stores the liquid L supplied from the liquid chamber 20a at a predetermined negative pressure just before the ejection head 11, preventing the liquid L from leaking from the ejection head 11.

The diaphragm 52 is a deformable sheet member made of a flexible material that defines the storage section 50a. A movable plate 56 is in close contact with the diaphragm 52. The diaphragm 52 and movable plate 56 are constantly biased by an elastic member 57 in a direction that increases the volume of the storage section 50a. The elastic member 57 is a coil spring installed between the housing 51 and the movable plate 56, and the biasing force of the elastic member 57 maintains the storage section 50a in a negative pressure state.

A restriction valve 54 is provided in the flow path 51c to restrict the supply of liquid L from the flow path 51c to the storage section 50a. The restriction valve 54 opens and closes the communication passage 51d between the flow path 51c and the storage section 50a. The restriction valve 54 includes a valve body 54a and an elastic member 54b, and the valve body 54a is constantly biased in the closing direction by the elastic member 54b. The valve body 54a has a shaft that passes through the communication passage 51d and enters the storage section 50a.

The operation of the negative pressure maintenance unit 50 will now be described. In state ST101, the restriction valve 54 is closed; in other words, the reservoir 50a is filled with a sufficient amount of liquid L. The valve element 54a is in close contact with the wall surrounding the communication passage 51d, restricting the inflow of liquid L from the flow path 51c into the reservoir 50a. In this state, a force is applied to the diaphragm 52 from the elastic member 57 via the moving plate 56 in a direction that expands the reservoir 50a. Furthermore, because the restriction valve 54 is closed, the liquid inside the reservoir 50a is under negative pressure. This allows the meniscus generated at the nozzle to be in a desirable state (moderately concave) when the liquid L is ejected from the nozzle of the ejection head. Note that the bulge of the diaphragm 52 is slightly exaggerated in state ST101 in Figure 10.

State ST102 shows the state in which the restriction valve 54 is open. In other words, when the restriction valve 54 is open, the remaining amount in the storage section 50a is insufficient and the system is waiting for liquid to be supplied from the intermediate tank 20. When the amount of liquid L in the storage section 50a decreases due to the ejection of liquid L from the ejection head, the diaphragm 52 displaces toward the restriction valve 54 against the elastic member 57. The moving plate 56 presses the valve body 54a of the restriction valve 54, and the valve body 54a moves away from the wall surrounding the communicating passage 51d, allowing liquid L to flow from the flow path 51c into the storage section 50a via the communicating passage 51d. Because the liquid L entering from the inlet pipe 51a is pressurized, it passes through the filter 53 and flows into the storage section 50a via the communicating passage 51d.

As the amount of liquid in the reservoir 50a increases, the diaphragm 52 gradually expands, and at the same time, the moving plate 56 moves away from the valve body 54a. As a result, the restriction valve 54 becomes closed, as shown in state ST101.

In this way, liquid L is supplied under pressure from the intermediate tank 20 to the storage section 50a while maintaining a negative pressure in the storage section 50a. While the displacement of the diaphragm 52 is exaggerated in Figure 10, in reality, the storage section 50a alternates between closed and open states with minute movements, maintaining a nearly constant negative pressure inside the storage section 50a.

(Pressure adjustment unit)
The configuration of the pressure adjustment unit 60 will now be described. Figure 11 is an explanatory diagram of the pressure adjustment unit 60. The pressure adjustment unit 60 includes an air pump 61 and multiple control valves 62A to 62D. The air pump 61 is an electric pump equipped with a diaphragm and a check valve inside, and is driven by a motor. The multiple control valves 62A to 62D are electric valves that switch the communication state between the air pump 61 and the pressure chamber 20b or the pipe 19f that forms the atmosphere communication path.

In this embodiment, a pressure sensor 73 and a constant pressure valve 63 are provided in the pipe 19e. The pressure sensor 73 detects the pressure of the gas in the pipe 19e, i.e., the pressure in the pressure chamber 20b. The constant pressure valve 63 is a valve that maintains the pressure chamber 20b at or below the upper limit pressure when the pressure in the pressure chamber 20b is pressurized. When the pressure in the pipe 19e reaches the upper limit pressure, the constant pressure valve 63 opens, connecting the pipe 19e to the atmosphere. This maintains the pressure chamber 20b at or below the upper limit pressure.

Figure 12 is a timing chart showing the opening and closing patterns of control valves 62A to 62D. In the figure, valves A to D refer to control valves 62A to 62D. The horizontal axis indicates pressurization, sealing, atmospheric release A, depressurization, atmospheric release B, and pressurization, indicating the operation of the pressure adjustment unit 60 with respect to pressure chamber 20b. Figure 13 is an explanatory diagram of the operation when control valves 62A to 62D are opened and closed in the order of pressurization, sealing, atmospheric release A, depressurization, and atmospheric release B shown on the horizontal axis of Figure 12.

State ST131 in Figure 13 is the valve state for pressurizing the pressure chamber 20b to a positive pressure. Control valve 62A is open, control valve 62B is closed, control valve 62C is open, and control valve 62D is closed. By operating the air pump 61 in each of these valve states, air is sucked in from the pipe 19f side and pressurized air is sent to pipe 19e. When pressure is adjusted through this pressurizing operation, the pressure chamber 20b gradually changes from atmospheric pressure to a positive pressure. When the pressure in pipe 19f exceeds the upper limit pressure after a predetermined time, the constant pressure valve 63 operates and the pressure in pressure chamber 20b becomes constant.

State ST132 is the valve state for sealing operation to maintain the pressure in pressure chamber 20b pressurized by the pressurization operation. Control valve 62A is closed, control valve 62B is open, control valve 62C is open, and control valve 62D is closed. In each of these valve states, pipe 19e side (pressure chamber 20b) is isolated from the air pump 61 and sealed. Furthermore, when the air pump 61 is driven, air circulates between control valves 62B and 62C and the air pump 61. Therefore, no air flows through pipe 19f side, whether the air pump 61 is operating or stopped.

State ST133 is the atmosphere release A operation that is passed through on the way to the next depressurization operation. This operation is to connect pressure chamber 20b to the atmosphere and return it from a positive pressure state to near atmospheric pressure in order to quickly change pressure chamber 20b, which is in a positive pressure state, to a negative pressure state. In atmosphere release A operation, control valve 62A is closed, control valve 62B is open, control valve 62C is open, and control valve 62D is open. In this case, air enters from the side of pipe 19e, passes through control valve 62D and control valve 62C, and exits into pipe 19f without passing through air pump 61.

State ST134 is the valve state for decompression operation to place pressure chamber 20b in a negative pressure state. Control valve 62A is closed, control valve 62B is open, control valve 62C is closed, and control valve 62D is open. By operating the air pump 61 in each of these valve states, air is sucked in from pipe 19e and discharged to pipe 19f. When pressure chamber 20b is at atmospheric pressure and pressure is adjusted by this decompression operation, pressure chamber 20b gradually becomes negative. After a predetermined time, the pressure in pressure chamber 20b becomes constant at a predetermined negative pressure according to the capacity of air pump 61. Note that in this embodiment, no negative pressure constant valve is provided, but if it is desired to limit the pressure to a predetermined negative pressure, a negative pressure constant valve may be provided in parallel with constant pressure valve 63.

State ST135 is the atmosphere release B operation that is passed through on the way to the next pressurization operation (state ST131). This operation is performed to quickly change the interior of pressure chamber 20b, which is in a negative pressure state, to a positive pressure state by connecting pressure chamber 20b to the atmosphere and returning the negative pressure to near atmospheric pressure. In atmosphere release B operation, control valve 62A is open, control valve 62B is open, control valve 62C is open, and control valve 62D is open. In this case, air enters from the side of pipe 19f, and then passes from control valve 62B through control valve 62A and into pipe 19e without passing through air pump 61.

Figure 14 shows a specific structural example of the pressure adjustment unit 60. In this structural example, the air pump 61, control valves 62A-62D, constant pressure valve 63, as well as the motor that serves as the drive source and the position detection sensor are all integrated into a single unit.

Motor 61a drives air pump 61 and control valves 62A-62D. Cam sensor 65 detects the initial position of cam member 64. Drive gear train 660 selectively transmits the driving force of motor 61a to air pump 61 and cam member 64. Drive gear train 660 also includes a clutch mechanism. Normally, when motor 61a is rotated in the forward direction, cam member 64 does not move and only air pump 61 operates. However, the clutch mechanism can also be used to rotate motor 61a in the forward direction and rotate cam member 64 in the reverse direction. Cam member 64 includes a camshaft and multiple plate cams that provide the timing and force to switch control valves 62A-62D.

Figure 15 is a schematic cross-sectional view showing the configuration of a representative control valve 62A. The cam lever 66 functions as a cam follower for the cam member 64 and displaces the valve rubber 622. The cam lever spring 67 biases the cam lever 66 in the direction of closing the valve. The valve rubber 622 forms an airtight space and controls the valve function itself by pressing a portion against an opposing portion. The seal portion 622A is a valve element that is part of the valve rubber 622 and deforms when pressed against an opposing portion to form a seal. Flow path 620 is the flow path upstream of the control valve 62A, and flow path 621 is the flow path downstream of the control valve 62A. The cam lever 66 rotates as the cam member 64 rotates, displacing the seal portion 622A. This allows communication between flow paths 620 and 621 to be switched between open and closed.

The positions of the cam member 64 corresponding to the pressurizing operation, sealing operation, atmosphere release A operation, depressurizing operation, and atmosphere release B operation illustrated in Figures 12 and 13 may be referred to as the pressurizing position, sealing position, atmosphere release A position, depressurizing position, and atmosphere release B position, respectively.

In this embodiment, the valve rubber 622 is integrated as a shared component of the control valves 62A-62D, the constant pressure valve 63, and the differential pressure valve 81 (described later). Figure 16 is a perspective view of the valve rubber 622. In addition to the seal portion 622A described above, the valve rubber 622 also has seal portions 622B-622D that form the control valves 62B-62D, seal portion 63a that forms the constant pressure valve 63, and seal portion 811 that forms the differential pressure valve 81 (described later). These seal portions 622A-622D, 63a, and 811 each have a diaphragm for the control valves 62A-62D, the constant pressure valve 63, and the differential pressure valve 81, and can operate independently, but are molded as a single component into the valve rubber 622.

The pressure regulation unit 60 configured as described above can regulate the pressure state of the pressure chamber 20b. The operation of the pressure regulation unit 60 can be broadly divided into the operation of the air pump 61 and the switching operation of the control valves 62A to 62D.

When the air pump 61 is operating, the drive gear train 660 is configured so that the driving force from the motor 61a is transmitted only to the air pump 61. Specifically, the air pump 61 is driven continuously while the motor 61a is rotating in the forward direction. When the control valves 62A to 62D are switched, the motor 61a is rotated in the reverse direction. In this case, the drive gear train 660 is configured so that the driving force of the motor 61a is transmitted to both the air pump 61 and the cam member 64. When the motor 61a is rotated in the reverse direction, the air pump 61 is driven in the opposite direction to when the motor 61a is rotating in the forward direction, but the air pump 61 is configured to pump in the same way regardless of the direction in which it is driven.

The driving force transmitted to the cam member 64 causes the cam member 64 to rotate, and each control valve 62A-62D opens and closes using the same mechanism and operation as the control valve 62A shown as a representative example in Figure 15. In other words, when the valve is in the closed state shown in Figure 15, the valve rubber 622 is pressed downward in the figure via the cam lever 66 due to the action of the cam lever spring 67. The seal portion 622A is pressed against the opposing portion and deforms, forming a tight seal, blocking the flow paths 620 and 621.

When the cam member 64 rotates and the convex portion of the cam surface abuts the cam lever 66, the cam lever 66 rotates clockwise in the figure against the cam lever spring 67. The valve rubber 622 is pulled upward in the figure, and the seal portion 622A separates from the opposing member, connecting the flow paths 620 and 621. The cam surface of the cam member 64 is configured so that each control valve 62A-62D opens and closes at the appropriate timing according to the timing chart in Figure 12. The desired operating state can be achieved simply by rotating the cam member 64 as needed.

In this embodiment, air is used as the pressure adjusting fluid for pressure chamber 20b, but a liquid working fluid such as hydraulic pressure may also be used. In that case, instead of opening to the atmosphere, a buffer tank for the liquid working fluid can be provided, the liquid working fluid can be released into it, and the buffer tank can be kept at atmospheric pressure.

(Atmospheric release unit)
The atmosphere vent unit 80 is a mechanism that opens the pressure chamber 20b to the atmosphere in response to an operation related to the replacement of the container 17 (hereinafter referred to as a replacement-related operation). In this embodiment, the replacement-related operation is the operation of opening the access covers 16A and 16B. When the access cover 16A or 16B is opened, the corresponding container 17 may be replaced by the user. For example, when the access cover 16A is opened, at least one of the containers 17 stored in the storage section 15A may be replaced. Furthermore, when the access cover 16B is opened, the container 17 stored in the storage section 15B may be replaced.

Replacement of the container 17 can be performed by the user at any time. If the container 17 corresponding to the intermediate tank 20 of the pressure chamber 20b is replaced while the pressure chamber 20b is in a negative pressure state, such as during a refilling operation, air bubbles may be sucked into the flow path of the liquid L from the pipe 19a. If air bubbles are sucked into the flow path, this can cause problems such as poor liquid ejection by the ejection head 11. In such a case, the atmosphere release unit 80 opens the pressure chamber 20b to the atmosphere, eliminating the negative pressure state and preventing air bubbles from being sucked into the flow path of the liquid L from the pipe 19a.

On the other hand, even if the container 17 corresponding to the intermediate tank 20 of the pressure chamber 20b is replaced while the pressure chamber 20b is in a positive pressure state, such as during a supply operation, there is little chance of air bubbles being sucked into the flow path of the liquid L from the pipe 19a. Opening the pressure chamber 20b to the atmosphere may require the recording operation to be interrupted, reducing productivity. Therefore, the atmosphere opening unit 80 of this embodiment opens the pressure chamber 20b to the atmosphere depending on the replacement-related operations and the operating state of the pressure adjustment unit 60.

Figure 17 (A) is an explanatory diagram showing the structure of the atmosphere release unit 80. The atmosphere release unit 80 includes a differential pressure valve 81 and a linkage valve 82. The differential pressure valve 81 includes a housing 810, a seal (valve body) 811, and an elastic member 812. The housing 810 has formed therein a passage 814 that communicates with the pressure chamber 20b via piping 19e, and a communication passage 815 that communicates with the passage 814. The housing 810 also has a communication pipe 813 that forms a communication passage with the linkage valve 82. A piping 84 is connected to the communication pipe 813. A seal 811 that opens and closes the communication pipe 813 is provided inside the housing 810. A through hole 811a is formed in the seal 811, and the passage 814 is constantly in communication with the space in which the elastic member 812 is located. The seal portion 811 is constantly biased in the direction of closing the communication pipe 813 by an elastic member 812. The elastic member 812 is, for example, a coil spring.

When the pressure inside the communicating pipe 813 is lower than or equal to the pressure in the passage 814, the seal portion 811 of the differential pressure valve 81 closes the communicating pipe 813. On the other hand, when the pressure inside the communicating pipe 813 becomes higher than the pressure in the passage 814, the seal portion 811 displaces away from the communicating pipe 813 against the bias of the elastic member 812, opening the communicating pipe 813. This establishes communication between the communicating pipe 813 and the passage 814. In this embodiment, the differential pressure valve 81 is a valve that opens the communicating pipe 813 when the pressure inside the pressure chamber 20b is lower than atmospheric pressure, and closes it otherwise.

As shown in Figure 16, the seal portion 811 is formed as part of the valve rubber 622, and by sharing the same components as the other valve components, the device can be made smaller and less expensive.

The interlocking valve 82 includes a housing 820, a seal portion (valve body) 811, a lever 824, an elastic member 825, a rod 826, and an elastic member 827. The illustrated example shows an interlocking valve 82 that is interlocked with the opening and closing of access cover 16A, but the interlocking valve 82 that is interlocked with the opening and closing of access cover 16B has a similar configuration. Note that access cover 16A is depicted in a simplified form in Figure 17 (A).

The housing 820 has a communication pipe 822 that forms a communication path with the differential pressure valve 81, and a communication pipe 823 that forms a communication path with the atmosphere. The communication pipe 822 is connected to a pipe 84, and the communication pipe 823 is connected to a pipe 83 that is open to the atmosphere. A seal 821 that opens and closes the communication pipe 822 is provided inside the housing 820.

Rod 826 is a member that engages with access cover 16A. In this embodiment, when access cover 16A is in the closed state, the tip of rod 826 abuts against access cover 16A. Elastic member 827 constantly urges rod 826 in the direction in which the tip abuts against access cover 16A. Elastic member 827 is, for example, a coil spring. When access cover 16A is in the closed state as shown in Figure 17 (A), elastic member 827 is in a contracted state and accumulates elastic force.

One end of the lever 824 is pivotally supported and can rotate freely around that axis. When the rod 826 is displaced upward in the figure, the lever 824 engages with the engaging portion 826a of the rod 826 and rotates. This displaces the seal portion 821 in a direction that opens the communicating pipe 822. When the seal portion 821 opens the communicating pipe 822, the communicating pipe 822 and the communicating pipe 823 communicate with each other. In other words, the communicating pipe 813 of the differential pressure valve 81 is opened to the atmosphere.

The elastic member 825 biases the lever 824 downward in the figure. The elastic member 825 is, for example, a coil spring. The elastic member 825 causes the lever 824 to constantly bias the seal portion 821 in a direction that closes the communicating pipe 822. When the seal portion 821 closes the communicating pipe 822, communication between the communicating pipes 822 and 823 is cut off. In other words, the communicating pipe 813 of the differential pressure valve 81 is cut off from the atmosphere.

With the above configuration, the interlocking valve 82 opens and closes mechanically in conjunction with the opening and closing of the access cover 16A. That is, when the access cover 16A is closed as shown in FIG. 17(A), the seal 821 closes the connecting pipe 813, and the interlocking valve 82 is closed. On the other hand, when the access cover 16A is opened, as shown in FIG. 17(B), the elastic member 827 biases the rod 826 in the direction D3, causing the lever 824 to rotate and the seal 821 to open the connecting pipe 823. This opens the interlocking valve 82, and the connecting pipes 822 and 823 communicate with each other. When the access cover 16A is closed again, the state shown in FIG. 17(A) is restored.

Figure 18 is an explanatory diagram of the operation of the atmosphere release unit 80 during the replacement work of the container 17. State ST181 shows the state when the pressure chamber 20b is under positive pressure and the access cover 16A is closed. This state is the state when the supply operation is being performed by the pressure adjustment unit 60. At this time, the interlocking valve 82 is closed, so there is no pressure fluctuation in the communicating pipe 813, and a positive pressure equivalent to that of the pressure chamber 20b is applied to the passage 814. Therefore, the differential pressure valve 81 is also closed. In other words, in this state, the pressure in the pressure chamber 20b is not affected by the differential pressure valve 81 and the interlocking valve 82.

State ST182 shows the state when pressure chamber 20b is under positive pressure and access cover 16A is open. In this embodiment, the recording device 1 maintains positive pressure in pressure chamber 20b even when the recording device 1 is in a standby state (i.e., when no recording operation is being performed) or when the recording device 1 is turned off. This is to ensure that the recording device 1 is ready to supply fluid immediately upon receiving a command for the next recording operation. Furthermore, the flow path from the intermediate tank 20 to the downstream limiting valve 54 remains pressurized, preventing air from entering the flow path. State ST182 corresponds to the state when the recording device 1 is performing a supply operation during a recording operation, is in a standby state for the next recording operation, or is turned off and the access cover 16A is open. In this state, the interlocking valve 82 opens, opening the connecting pipe 813 to the atmosphere. Since the passage 814 is subjected to a positive pressure equivalent to that of pressure chamber 20b, the differential pressure valve 81 remains closed. In other words, in this state, the pressure in the pressure chamber 20b does not fluctuate when the access cover 16A is opened due to the action of the differential pressure valve 81 and interlocking valve 82.

State ST183 shows the state when pressure chamber 20b is under negative pressure and access cover 16A is closed. This state corresponds to the state when a replenishment operation is being performed. At this time, interlocking valve 82 is closed, so there is no pressure fluctuation in connecting pipe 813, and passage 814 is subjected to a negative pressure equivalent to that of pressure chamber 20b. At this time, a force acts on valve rubber 622 of differential pressure valve 81 to open seal portion 811, but because interlocking valve 82 is closed and no air flows, differential pressure valve 81 does not open and remains closed. In other words, in this state, the pressure in pressure chamber 20b is not affected by differential pressure valve 81 and interlocking valve 82.

State ST184 shows the state when pressure chamber 20b is in a negative pressure state and access cover 16A is open. This state corresponds to a state in which access cover 16A is opened for some reason while a replenishment operation is being performed.

The replenishment operation is performed at any time during a period when no recording operation is being performed. If the operation is designed to be performed without the user being aware of the timing, it is possible that the user may accidentally open the access cover 16A in an attempt to replace the container 17 during a replenishment operation.

There is no particular problem if the access cover 16A is simply opened, but a problem occurs if the container 17 is removed from the storage section 15A during the refilling operation. The problem is that air can enter through the joint connecting the container 17 and the piping 19a. If air enters the flow path and reaches the ejection head 11, it may cause problems with the ejection operation.

The reason air enters through the joint here is that there is a negative pressure inside the flow path from the container 17 to the intermediate tank 20. This is because the pressure chamber 20b is depressurized to a negative pressure state for the replenishment operation. Therefore, when the user opens the access cover 16A during the replenishment operation, the pressure chamber 20b is quickly returned from the negative pressure state to atmospheric pressure, preventing air from entering the flow path.

In state ST184, the interlocking valve 82 is open, so the connecting pipe 813 is open to the atmosphere, and a negative pressure equivalent to that of pressure chamber 20b is applied to passage 814, causing the differential pressure valve 81 to open. When the differential pressure valve 81 opens, air rushes into pressure chamber 20b, causing pressure chamber 20b to reach atmospheric pressure in a short period of time. In other words, in this state, the action of the differential pressure valve 81 and interlocking valve 82 causes the pressure inside pressure chamber 20b to quickly change from a negative pressure state to atmospheric pressure when access cover 16A is opened. Therefore, even if the user removes container 17 from storage section 15A, air is prevented from entering the flow path.

As explained above, according to this embodiment, when pressure chamber 20b is in a positive pressure state, the positive pressure state within pressure chamber 20b is maintained even if access cover 16A is opened. Therefore, even if the user opens access cover 16A at any time, it is possible to avoid the situation where downtime is required to re-pressurize before the next recording operation. Furthermore, since pressurization of the flow path from intermediate tank 20 to restriction valve 54 is maintained even during the subsequent standby state, it is possible to prevent air from entering the flow path.

On the other hand, when pressure chamber 20b is in a negative pressure state, opening access cover 16A quickly returns the pressure in pressure chamber 20b from the negative pressure state to atmospheric pressure. Therefore, even if the user accidentally opens access cover 16A during a refilling operation, it is possible to prevent air from unintentionally entering the liquid flow path.

In this embodiment, the differential pressure valve 81 is positioned closer to the pressure chamber 20b than the interlocking valve 82, but their positions may be reversed as long as they are connected in series.

<Control circuit>
The control circuit of the supply unit 18 will now be described. FIG. 19 is a block diagram showing the control circuit 100 of the supply unit 18. The control circuit 100 comprises at least one processor and at least one storage device, and the processor executes a program stored in the storage device. Specifically, the control circuit 100 comprises a CPU 101, a RAM 102, and a ROM 103. The ROM 103 stores programs, various settings, etc. The RAM 102 is responsible for temporarily storing programs and control information, etc. The CPU 101 executes the program stored in the ROM 103.

The CPU 101 can communicate with the main control circuit 200 of the recording device 1 via the interface 104. The main control circuit 200 controls recording operations, etc. The control performed by the control circuit 100 may be configured to be performed by the main control circuit 200.

The timer 105 measures time. The motor driver 106 drives the motor 61a according to commands from the CPU 101. The motor encoder 61b detects the rotation direction and angle of the motor 61a. The CPU 101 can control the motor 61a based on the detection results of the motor encoder 61b, the cam sensor 65, the remaining amount detection sensors 71 and 72, and the pressure sensor 73.

<Control example>
An example of control of the supply unit 18 executed by the CPU 101 of the control circuit 100 will be described.

(Replenishment operation)
20 and 21 are flowcharts showing an example of the refilling operation. This operation is performed when the remaining amount of liquid L in the liquid chamber 20a has decreased, in order to return the liquid to the full capacity of 100%, as shown in state ST62 in Fig. 6. This operation is basically performed when the remaining amount of liquid L in the liquid chamber 20a has decreased to region II or below.

In S101, it is confirmed that the cam member 64 is in the sealed position. In this embodiment, it is assumed that when the recording device 1 is in a standby state, the cam member 64 is in the sealed position and the pressure chamber 20b is maintained in a positive pressure state. If the recording device 1 is in a standby state, there is no need to re-pressurize the pressure chamber 20b when transitioning from the standby state to the next recording operation, thereby shortening the recording time. Furthermore, since the liquid flow path is pressurized, it is less likely that air will enter the flow path from the outside. In S101, if it is determined that the cam member 64 is in a different position, the motor 61a is driven based on the detection results of the cam sensor 6 and motor encoder 61b, and the cam member 64 is moved to the sealed position.

Next, in S102, the motor 61a is rotated in the reverse direction. This causes the cam member 64 to rotate in the forward direction, moving from the sealed position through the atmosphere release A position toward the reduced pressure position. When passing through the atmosphere release A position, the pressure chamber 20b communicates with the atmosphere via the pressure adjustment unit 60, so the positively pressurized air in the pressure chamber 20b is suddenly released, and the pressure in the pressure chamber 20b approaches atmospheric pressure.

In this embodiment, the cam member 64 simply passes through the atmosphere release position A without stopping, but if, for example, the flow path is narrow and it is difficult to exhaust air, the cam member 64 may be temporarily stopped at the atmosphere release position A.

Next, in S103, it is determined whether the cam member 64 has transitioned to the depressurized position. The motor 61a continues to be driven until the transition is complete. Once the transition is complete, the rotation direction of the motor 61a is reversed to the forward direction in S104. This stops the rotation of the cam member 64 at the depressurized position and the air pump 61 begins operating. The air in the pressure chamber 20b is exhausted by the pressure adjustment unit 60, and the pressure in the pressure chamber 20b is reduced. As the air pump 61 continues to be driven, the pressure in the pressure chamber 20b is reduced to a negative pressure value determined by the capacity of the air pump 61. In this case, the restriction unit 25 quickly operates to state ST52 in Figure 5.

Next, in S105, the amount of liquid L supplied from the container 17 to the liquid chamber 20a is monitored based on the detection results of the remaining amount detection sensors 71 and 72. Once it is confirmed that the remaining amount of liquid L has entered area I, the system waits for t1 seconds to maintain this state. This is because, due to flow rate constraints, it takes some time for the remaining amount in the liquid chamber 20a to reach 100% of its full capacity. Time t1 is set in advance taking into account the viscosity of the liquid L, the cross-sectional area and length of the flow path from the container 17 to the liquid chamber 20a, etc. After t1 seconds have elapsed, the remaining amount in the liquid chamber 20a is considered to have reached 100% of its full capacity.

If the remaining amount in the container 17 is insufficient, the container 17 may become empty after the remaining amount exceeds the threshold Low in Figure 8, and the total capacity may not reach 100%. In this case, it is still assumed that the container 17 has been replenished to 100% of its total capacity, and the remaining amount information is corrected based on the detection results of the remaining amount detection sensors 71 and 72 as the liquid in the liquid chamber 20a is consumed in subsequent supply operations.

If it is not possible to detect in S105 that the remaining amount has entered remaining amount region I, the process waits for t2 seconds in S106. If, after waiting for t2 seconds, it is not possible to confirm that the remaining amount does not exceed the threshold Low in Figure 8 and is in region I, it is determined that the container 17 has become empty and the liquid replenishment operation cannot be completed. In this case, it is better to notify the user that the container 17 is empty, so the no liquid amount flag information is turned on in S107. The main control circuit 200 is notified that this flag information is on, and the main control circuit 200 executes the corresponding process (notifying the user, etc.).

On the other hand, if the remaining amount in the liquid chamber 20a has not reached region IV, the printing operation can continue, so proceed to the next step in this state.

With this, the refilling operation itself is complete, so in order to move on to the next operation of supplying liquid L to the ejection head 11, in S109 the motor 61a is switched to rotating in the reverse direction. This causes the cam member 64 to start rotating in the forward direction again. The cam member 64 moves from the depressurized position through the atmosphere release B position towards the pressurized position. When passing through the atmosphere release B position, the pressure chamber 20b is connected to the atmosphere via the pressure adjustment unit 60, so air flows in from the outside into the pressure chamber 20b, which is at negative pressure, and the pressure of the pressure chamber 20b approaches atmospheric pressure.

In this embodiment, the cam member 64 simply passes through the atmosphere release B position without stopping, but if, for example, the flow path is narrow and it is difficult for air to flow in, the cam member 64 may be temporarily stopped at the atmosphere release B position.

Next, in S110, it is determined whether the cam member 64 has transitioned to the pressurized position. The motor 61a continues to be driven until the transition is complete. Once the transition is complete, in S111, the rotation direction of the motor 61a is reversed to the forward direction. This stops the rotation of the cam member 64 at the pressurized position and the air pump 61 is in operation. The pressure chamber 20b is pressurized by air flowing in from the outside via the pressure adjustment unit 60. The maximum pressure of the pressure chamber 20b rises to the positive pressure value set by the constant pressure valve 63. Since this positive pressure value determines the supply pressure of the liquid supplied to the ejection head 11, it is desirable to set this value as accurately as possible. In this embodiment, the constant pressure valve 63 is equipped with an internal spring, and is designed to release air to the outside if the pressure exceeds this spring force. Therefore, this spring force must be highly accurate, or the spring force must be adjusted if necessary.

Next, in S112, the detection result of the pressure sensor 73 is used to determine whether the pressure in the pressure chamber 20b has exceeded a predetermined pressure (positive pressure) P1. Here, P1 is a pressure slightly lower than the opening pressure of the constant pressure valve 63. If the pressure in the pressure chamber 20b has exceeded P1, the process proceeds to the next step. Note that while the pressure sensor 73 is provided in this embodiment, providing a pressure sensor increases costs, so if this is undesirable, it is possible to configure the system without the pressure sensor 73. In this case, the capacity of the air pump 61, the volume of the pressure chamber 20b, etc. are taken into consideration, and the time required for the pressure to sufficiently exceed the opening pressure of the constant pressure valve 63 is set. In other words, the target positive pressure value may be determined to have been reached when the motor 61a has been driven for the set time since it began rotating in the forward direction in S111.

Next, in S113, the drive of the motor 61a is temporarily stopped. At this point, the pressure chamber 20b is already pressurized to a predetermined positive pressure. That is, the stopper 27 of the restriction unit 25 is retracted, the local deformation of the wall 22 (elastic deformation of part A in state ST61 in Figure 6) is eliminated, and the wall 22 is under positive pressure, resulting in the supply of liquid L. In other words, the liquid in the liquid chamber 20a has begun to be transported toward the ejection head 11. Depending on the state from the intermediate tank 20 to the negative pressure maintenance unit 50, if a corresponding amount of liquid L flows into the storage section 50a, the volume of the liquid chamber 20a will decrease, and the volume of the pressure chamber 20b will increase accordingly. As a result, the pressure in the pressure chamber 20b will decrease. Since it is necessary to keep the pressure in the pressure chamber 20b as constant as possible, the pressure state will be checked in the next step.

Next, in S114, the detection result of the pressure sensor 73 is checked to see if the pressure in the pressure chamber 20b falls below pressure P1 even after a preset time t3 seconds has elapsed. If pressure P1 is maintained after t3 seconds have elapsed, it is determined that the amount of liquid transferred from the liquid chamber 20a to the ejection head 11 side is small, and the process proceeds to the next step. If the pressure in the pressure chamber 20b falls below pressure P1 within t3 seconds, re-pressurization is required. In S115, the motor 61a is rotated in the forward direction to re-pressurize the pressure chamber 20b. In this case, if the remaining amount of liquid in the liquid chamber 20a has decreased to region IV, liquid cannot be supplied to the ejection head 11 side no matter how much positive pressure is applied. For this reason, in S116, the remaining amount of liquid in the liquid chamber 20a is checked. If it has not decreased to region IV, the process returns to S114. If the remaining amount of liquid in the liquid chamber 20a has decreased to region IV, the liquid chamber 20a needs to be re-replenished, and the process returns to S102.

Next, in S117, the remaining amount of liquid L in the liquid chamber 20a after the pressure in the pressure chamber 20b has stabilized (i.e., after the liquid supply operation to the ejection head 11 side has stopped) is checked. If the remaining amount is in region I, proceed to the next step. If the remaining amount is not within region I, another replenishment operation is required, and processing returns to S102.

Next, in S118, the motor 61a is rotated in the reverse direction, causing the cam member 64 to begin moving to the sealed position. When it is determined in S119 that the cam member 64 has completed moving to the sealed position, the rotation of the motor 61a is stopped in S120, and the processing ends.

(Supply operation)
22 is a flowchart showing an example of a supply operation process during a recording operation, that is, a process related to control of pressure management of the pressure chamber 20b during a recording operation.

When the recording operation starts, in S201 it is confirmed that the cam member 64 is in the sealed position. This is the same process as S101 in Figure 20. Next, in S202, the motor 61a is rotated in the forward direction. Here, due to the action of the clutch mechanism in the drive gear train 660, the motor 61a rotates in the forward direction during the section returning from the sealed position to the pressurized position, causing the cam member 64 to rotate in the reverse direction.

Next, in S203, it is determined whether the cam member 64 has transitioned to the pressure-applying position. The motor 61a continues to be driven until the transition is complete, and once the transition is complete, the motor 61a is stopped in S204. If the cam member 64 is in the pressure-applying position, rotating the motor 61a in the forward direction makes it possible to apply pressure to the pressure chamber 20b.

Next, in S205, the detection results of the pressure sensor 73 during the recording operation are monitored. If the pressure in the pressure chamber 20b is greater than pressure P1, in S207 the motor 61a remains stopped. If the pressure in the pressure chamber 20b falls below pressure P1, in S206 the motor 61a is rotated in the forward direction to begin pressurizing the pressure chamber 20b.

The pressure in the pressure chamber 20b decreases as the remaining amount of liquid in the liquid chamber 20a decreases due to the ejection of liquid L from the nozzles of the ejection head 11. Furthermore, if there is a long wait time without performing a printing operation, a small amount of air may leak from one of the sealed parts of the pressure chamber 20b, causing the pressure to drop. In such a case, the pressure chamber 20b is re-pressurized to the pressure required for the supply operation. Returning to S205, if the pressure in the pressure chamber 20b is greater than pressure P1, the motor 61a is stopped in S207, and the re-pressurization ends.

Next, in S208, it is determined through communication with the main control circuit 200 whether the recording operation is continuing. If the recording operation is continuing, the process returns to S205 and continues to monitor the pressure in the pressure chamber 20b. If the recording operation has ended, the process proceeds to S209, where the motor 61a is rotated in the reverse direction to transition the cam member 64 to the sealing position.

Next, in S210, it is determined whether the cam member 64 has transitioned to the sealed position. The motor 61a continues to be driven until the transition is complete, and once the transition is complete, the motor 61a is stopped in S211. This completes the control of the supply operation during the recording operation.

(Remaining amount detection)
Fig. 23 is a flowchart showing an example of a process for detecting the remaining amount of ink in the ink chamber 20a during a printing operation. The process in Fig. 23 is executed appropriately together with the process shown in Fig. 22, and monitors the remaining amount of ink in the ink chamber 20a while monitoring the detection results of the remaining amount detection sensors 71 and 72 when the printing operation starts.

If the remaining amount is in Area I (Figure 8) in S301, remaining amount monitoring continues. If the remaining amount falls below the threshold Low (Figure 8), proceed to the next step. In S302, a replenishment operation is performed. The processing related to the replenishment operation is as described with reference to Figures 20 and 21. Note that replenishment operations during printing are performed at timing set so as not to stop the printing operation or reduce throughput.

Next, in S303, the remaining amount in the liquid chamber 20a after the refilling operation is checked. If the remaining amount exceeds the threshold Low (Figure 8) and is in region I (Figure 8), the process returns to S301 to continue monitoring the remaining amount. If the remaining amount is below the threshold Low (Figure 8), the process checks which region the remaining amount is in and proceeds to the next step to take appropriate action.

In S304, it is determined whether the remaining amount in the liquid chamber 20a is in Region II (Figure 8). If the remaining amount is not in Region II, processing proceeds to S308. If the remaining amount is in Region II, processing proceeds to S305. Here, if the remaining amount does not exceed the threshold Low (Figure 8) even after the replenishment operation in S302, it is determined that the container 17 is empty, and a flag is turned on in S107 of Figure 20. However, since recording can still be continued in this state, if recording is in progress, the recording operation is not interrupted for the replenishment operation. Therefore, if it is determined in S304 that the remaining amount is in Region II, a warning that the liquid level is low is sent to the main control circuit 200 in S305. The main control circuit 200 can notify the user by displaying a warning, for example, using the operation unit 14.

In S306, the process branches depending on the user's response to the warning. The user can select a response via, for example, the operation unit 14. If the user selects replacing the container 17, the process proceeds to S307, where the user replaces the container 17, followed by the replenishment process shown in Figures 20 and 21. The replenishment process restores the remaining amount to region I (Figure 8), and the process then returns to S301. On the other hand, if the user determines that replacing the container 17 is not necessary at that point and selects to continue the recording operation, the process proceeds to S315, where it is determined whether the remaining amount is in region II. The process of S315 is repeated until the remaining amount is no longer in region II, and when it is determined that the remaining amount is no longer in region II, the process proceeds to S308.

Next, in S308, it is determined whether the remaining amount in the liquid chamber 20a is in region III (Figure 8). If the remaining amount is not in region III (Figure 8), it can be determined that the remaining amount is already in region IV (Figure 8), in which case the process proceeds to S313, which will be described later. If the remaining amount is in region III (Figure 8), in S309 a warning is sent to the main control circuit 200 that the liquid level has run out. In S310, the main control circuit 200 can stop the printing operation at a good time and notify the user by displaying a warning urging them to replace the container 17.

Next, in S311, the process branches depending on the user's response to the warning. The user can select a response, for example, via the operation unit 14. The user can choose to replace the container 17 on the spot, or continue the recording operation despite the fact that there is almost no ink remaining. If the user selects to replace the container 17, the process proceeds to S307, where the user replaces the container 17 and then performs the replenishment operation shown in Figures 20 and 21. If the user selects to continue the recording operation, the process proceeds to S312.

In S312, it is determined whether the remaining amount in the liquid chamber 20a is in region IV (Figure 8). If the remaining amount is not in region IV (Figure 8), recording is still possible, so the recording operation continues. If the remaining amount is in region IV (Figure 8), recording cannot continue, so the process proceeds to S313.

In S313, a warning is sent to the main control circuit 200 that the liquid level in the liquid chamber 20a has run out. The main control circuit 200 can then use, for example, the operation unit 14 to notify the user by displaying a warning that the recording operation cannot continue. Then, in S314, the recording operation is stopped and the system waits until the user replaces the container 17.

Next, we will explain the remaining amount detection control at the end of standby, which is used to check the remaining amount in the liquid chamber 20a when the recording device 1 is turned on or after a long standby period. Figure 24 is a flowchart. As a prerequisite for this control, when the recording device 1 is turned off or before entering a long standby period, area information indicating which area (Figure 8) the remaining amount in the liquid chamber 20a was in is stored in RAM 102 as remaining amount information.

In S401, the area information Roff is read from RAM 102. Next, in S402, the current area information Ron is determined based on the detection results of remaining amount detection sensors 71 and 72. Next, in S403, it is confirmed whether the area information Roff matches the areas indicated by area Ron, and if they match, normal startup operation begins. Thereafter, if the recording device 1 is turned off or enters a long-term standby state, the area information Roff at that time is stored in RAM 102 in S404.

If the region information Roff and region information Ron do not match in S403, this means that the remaining amount of liquid in the liquid chamber 20a has changed during standby. In particular, if the region indicated by the region information Ron is one in which the remaining amount of liquid Lno is low compared to the region information Roff, it is assumed that an unintended liquid leak has occurred. Since a malfunction may have occurred in some part of the supply unit 18, error processing is performed in S405. Here, for example, liquid leakage error information is notified to the main control circuit 200. The main control circuit 200 then takes action to prevent further printing operations from continuing, and can notify the user of the malfunction using the operation unit 14.

<Summary>
According to the atmosphere release unit 80 of this embodiment, the positive pressure state of the pressure chamber 20b is maintained even if an exchange-related operation is performed during a supply operation or the like that places the pressure chamber 20b in a positive pressure state. Due to this action, the pressure chamber 20b maintains a positive pressure state regardless of an exchange-related operation, so the supply operation can be continued and the liquid can be supplied immediately when the next recording operation command is received. Furthermore, because the flow path from the intermediate tank 20 to the downstream limiting valve 54 is continuously pressurized, there is an effect of suppressing the phenomenon of air entering the flow path.

On the other hand, if a replacement operation is performed during a refill operation in which pressure chamber 20b is in a negative pressure state, pressure chamber 20b is adjusted to quickly return to atmospheric pressure. This action has the effect of preventing air from entering the flow path through the joint even if container 17 is inadvertently removed from storage section 15A (or storage section 15B) during a liquid refill operation.

In addition, the provision of the regulating unit 25 has the effect of reducing variations in the supply pressure of the liquid L from the intermediate tank 20 to the ejection head 11, even immediately after the refill operation from the container 17 to the intermediate tank 20 has been performed. As a result, the ejection operation from the ejection nozzle of the ejection head 11 becomes stable.

In addition, by making the wall 22 and flexible member 26 diaphragm-shaped and made of flexible material, a mechanism with variable volume can be created with a simple configuration, which has the effect of reducing the size and cost of the device.

In addition, by independently driving the four control valves 62A-62D in the pressure adjustment unit 60 and providing a sealed position and an open-to-atmosphere position as cam positions, it is possible to maintain the pressure chamber 20b in a pressurized state during standby. This also has the effect of shortening the time required to change the pressure chamber 20b from positive pressure to negative pressure or from negative pressure to positive pressure.

In addition, in the pressure adjustment unit 60, the valve rubber 622 is integrally molded as a part shared by the control valves 62A to 62D, which has the effect of reducing the size of the device and reducing costs. Furthermore, by integrating the function of the constant pressure valve 63 into the valve rubber 622, further reductions in size and costs can be expected.

In addition, the detection lever 70 is constantly in contact with the abutment member 24, which moves integrally with the wall body 22, and the swinging state of the detection piece 70c is detected by the remaining amount detection sensors 71 and 72, making it possible to detect the remaining amount in the liquid chamber 20a. Furthermore, by using dot counting in combination, it is possible to detect the remaining amount more precisely. Furthermore, by detecting the remaining amount in the liquid chamber 20a, it is possible to detect when the liquid in the container 17 has run out, even without providing a sensor to detect the remaining amount in the container 17.

In addition, by configuring the device to detect whether there is a significant change in the remaining amount of liquid in the liquid chamber 20a before and after a long standby period when no recording operation is performed, unintended liquid leakage can be detected, thereby improving reliability.

Second Embodiment
In the first embodiment, the opening operation of the access cover 16A or 16B is exemplified as an example of a replacement-related operation, but other operations may be used. For example, in a configuration in which a top cover of the recording device is opened to replace a container, the replacement-related operation may be the opening operation of the top cover. Also, the replacement-related operation may be the operation of removing the container 17 from the storage unit 15A or 15B. Alternatively, in a configuration in which the user instructs replacement of the container 17 on the operation unit and the container 17 can be replaced, the replacement-related operation may be a replacement operation on the operation unit. In this case, for example, the configuration of the third embodiment described below may be used.

Third Embodiment
A sensor may be provided to detect the exchange-related operation, and processing may be performed based on the detection result.

Figure 25 is a block diagram of the control circuit 100 of this embodiment. Differences from the example of Figure 19 will be explained below. The recording device 1 is equipped with cover sensors 74A and 74B as sensors for detecting replacement-related operations, and the control circuit 100 is able to acquire the detection results of these sensors. Cover sensor 74A is a sensor that detects the open/closed state of access cover 16A, and cover sensor 74B is a sensor that detects the open/closed state of access cover 16B. Cover sensors 74A and 74B are, for example, optical sensors, and are positioned so that they are ON when the corresponding cover is open and OFF when it is closed.

Figure 26 is a flowchart showing an example of processing executed by the CPU 101 of the control circuit 100, which is the process of monitoring the access cover during a replenishment operation. If the pressure chamber 20b is in a negative pressure state and the pressure chamber 20b is returned to atmospheric pressure by the atmosphere release unit 80, the suction of liquid L from the container 17 to the liquid chamber 20a will end. In this embodiment, the replenishment operation is interrupted and the necessary notification is given to the user.

The processing in Figure 26 is initiated and executed in parallel with the replenishment operations shown in Figures 20 and 21. In S501, the detection results of cover sensors 74A and 74B are obtained, and it is determined whether access cover 16A and access cover 16B are both closed. If it is determined that access cover 16A and access cover 16B are both closed, the processing proceeds to step S502. If it is determined that at least one of access cover 16A and access cover 16B is open, the processing proceeds to step S503.

In S502, it is determined whether the replenishment operation has finished. If the replenishment operation has finished, the process ends. If the replenishment operation has not finished, the process returns to S501. As a result, as long as both access covers 16A and 16B are closed during the replenishment operation, the process loop formed by S501 and S502 continues to monitor access covers 16A and 16B.

In S503, the replenishment operation is interrupted. More specifically, regardless of which of the steps in Figures 20 and 21 that are being executed in parallel with the processing of Figure 26 is being executed, motor 61a is forcibly stopped and processing is terminated. In S504, when access cover 16A or access cover 16B is opened, a warning is sent to the main control circuit 200 to inform the user that replenishment has been interrupted. The main control circuit 200 can notify the user by displaying a warning, for example, using the operation unit 14. This notification may also be performed by sound or light (warning light) that notifies the user of the warning.

In this embodiment, the monitoring process shown in Figure 26 is started and ended in conjunction with the start and end of the replenishment operation, but it is sufficient if the opening of access covers 16A and 16B when pressure chamber 20b is in a negative pressure state can be detected without fail. For example, the monitoring period may be limited by timing the start of the process in Figure 26 to coincide with the start of S104 in Figure 20, and determining whether S502 is completed by determining whether S109 in Figure 20 has completed. Alternatively, the monitoring period may be limited by adding the condition that the pressure detected by pressure sensor 73 is negative pressure to the determination in S501.

<Fourth embodiment>
In the first embodiment, the atmosphere vent unit 80 is configured to mechanically open the pressure chamber 20b to the atmosphere in response to a replacement-related operation, but the pressure chamber 20b may be opened to the atmosphere by control. For example, the interlocking valve 82 may be replaced with an electronically controlled valve, and a sensor may be provided to detect a replacement-related operation, so that the electronically controlled valve is opened when the replacement-related operation is detected by the sensor.

Alternatively, the pressure adjustment unit 60 may not have an atmosphere release unit 80, and when a replacement-related operation is detected by a sensor that detects the replacement-related operation, the pressure adjustment unit 60 may be set to the atmosphere release A position to release the atmosphere. In other words, the pressure adjustment unit 60 may function as a unit for releasing the atmosphere. This control is described below. In this embodiment, cover sensors 74A and 74B are provided, similar to the example in Figure 25.

Figure 27 is a flowchart showing an example of processing executed by the CPU 101 of the control circuit 100, and shows an example of processing for monitoring the access cover and venting to the atmosphere when the access cover is open. The processing in Figure 27 is started simultaneously with the replenishment operations shown in Figures 20 and 21, and is executed in parallel.

S601, S602, and S603 are similar to S501, S502, and S503 in Figure 26, respectively. The closed state of access covers 16A and 16B is monitored, and if it is detected that access cover 16A or access cover 16B is open, the replenishment operation is interrupted.

In S604, the motor 61a is rotated in the reverse direction, and the cam member 64 begins to move to the atmosphere-open position A. When it is determined in S605 that the cam member 64 has completed moving to the atmosphere-open position A, the rotation of the motor 61a is stopped in S606. This opens the pressure chamber 20b to the atmosphere. S607 is the same process as S504 in Figure 26, and a warning is sent to the main control circuit 200 to inform the user that replenishment has been interrupted due to the opening of the access cover 16A or access cover 16B.

In addition, by having an atmosphere release unit 80 and also performing atmosphere release using the pressure adjustment unit 60 as described above, the atmosphere release can be completed in a shorter time.

Fifth Embodiment
In the first embodiment, the regulating unit 25 is provided, but the regulating unit 25 may not be provided.

<Other Embodiments>
The present invention can also be realized by supplying a program that realizes one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., an ASIC) that realizes one or more of the functions.

<Summary of the embodiment>
The above-described embodiments disclose at least the following recording apparatus.

Item 1.
a liquid chamber (20a) that receives liquid from a liquid container (17) and stores the liquid to be supplied to a discharge means (11) that discharges the liquid onto a recording medium, and a forming means (21) that forms a pressure chamber (20b) adjacent to the liquid chamber (20a);
a wall (22) that separates the liquid chamber (20a) from the pressure chamber (20b) and that changes the volume of the liquid chamber (20a) by being displaced in accordance with the pressure of the pressure chamber (20b);
a pressure adjusting means (60) that adjusts the pressure of the pressure chamber (20b) to perform a replenishing operation of introducing liquid from the liquid container (17) into the liquid chamber (20a) and a supply operation of supplying liquid from the liquid chamber (20a) to the discharge means (11);
and an atmosphere opening means (80) that opens the pressure chamber (20b) to the atmosphere in response to an operation related to replacement of the liquid container (17) during the refilling operation, but does not open the pressure chamber (20b) to the atmosphere in response to the operation during the supplying operation.
A recording device (1).

Item 2.
The recording device (1) according to item 1,
The atmosphere opening means (80)
a differential pressure valve (81) that switches between communication and cut-off between a first passage (814) and a second passage (813) in communication with the pressure chamber (20b) and the second passage (813) depending on a pressure difference between the first passage (814) and the second passage (813);
and a linkage valve (82) that switches a third passage (822) communicating with the second passage (813) from a closed state to an open state to the atmosphere in response to the operation.
A recording device characterized by:

Item 3.
The recording device (1) according to item 1,
When the pressure chamber (20b) is in a negative pressure state, the wall (22) is displaced to increase the volume of the liquid chamber (20a),
The pressure adjusting means (60)
In the replenishing operation, the pressure chamber (20b) is adjusted to a negative pressure state to introduce liquid from the liquid container into the liquid chamber (20a),
In the supply operation, the pressure chamber (20b) is adjusted to a positive pressure state, and liquid is supplied from the liquid chamber (20a) to the discharge means (11).
A recording device characterized by:

Item 4.
Item 3. The recording device (1) according to item 3,
The atmosphere opening means (80)
a differential pressure valve (81) that switches between communication and cut-off between a first passage (814) and a second passage (813) in communication with the pressure chamber (20b) and the second passage (813) depending on a pressure difference between the first passage (814) and the second passage (813);
a linkage valve (82) that switches a third passage (822) communicating with the second passage (813) from a closed state to an open state to the atmosphere in response to the operation,
the differential pressure valve (81) connects the first passage (814) with the second passage (813) when the pressure in the first passage (814) is lower than that in the second passage (813);
A recording device characterized by:

Item 5.
The recording device (1) according to any one of items 1 to 4,
access covers (16A, 16B) for opening and closing the storage sections (15A, 15B) of the liquid container (17);
The operation is an opening operation of the access covers (16A, 16B).
A recording device characterized by:

Item 6.
The recording device (1) according to item 2 or 4,
The pressure adjusting means (60)
a pump (61);
a plurality of control valves (62A-62D) provided between the pump and the pressure chamber (20b);
an operation of pressurizing the pressure chamber (20b) and an operation of depressurizing the pressure chamber (20b) by the pump by a combination of opening and closing of the plurality of control valves (62A-62D);
The differential pressure valve (81) and the plurality of control valves (62A-62D) are integrated with each other in some parts (622A-622D, 811).
A recording device characterized by:

Item 7.
a liquid chamber (20a) that receives liquid from a liquid container (17) and stores the liquid to be supplied to a discharge means (11) that discharges the liquid onto a recording medium, and a forming means (21) that forms a pressure chamber (20b) adjacent to the liquid chamber (20a);
a wall (22) that separates the liquid chamber (20a) from the pressure chamber (20b) and that changes the volume of the liquid chamber (20a) by being displaced in accordance with the pressure of the pressure chamber (20b);
a pressure adjusting means (60) for adjusting the pressure of the pressure chamber (20b);
and an atmosphere opening means (80) for switching whether or not the pressure chamber (20b) is opened to the atmosphere,
When the pressure chamber (20b) is in a negative pressure state, the wall (22) is displaced to increase the volume of the liquid chamber (20a),
The atmosphere opening means (80)
the pressure chamber (20b) is opened to the atmosphere in response to an operation related to replacement of the liquid container (17) when the pressure chamber (20b) is in a negative pressure state, but the pressure chamber (20b) is not opened to the atmosphere in response to the operation when the pressure chamber (20b) is in a positive pressure state;
A recording device (1).

Item 8.
Item 7: A recording device according to item 7,
The pressure adjusting means (80)
a pump (61);
a plurality of control valves (62A-62D) provided between the pump (61) and the pressure chamber (20b);
The pump (61) performs an operation of pressurizing the pressure chamber (20b), an operation of depressurizing the pressure chamber (20b), and an operation of opening the pressure chamber (20b) to the atmosphere by combining opening and closing of the plurality of control valves (62A-62D).
A recording device characterized by:

Item 9.
Item 9. The recording device according to any one of items 1 to 8,
a control means (100) for interrupting the refilling operation in response to an operation relating to replacement of the liquid container during the refilling operation;
A recording device characterized by:

Item 10.
Item 9. The recording device according to item 9,
The control means (100) performs a process for warning a user when the replenishment operation is interrupted.
A recording device characterized by:

The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, items are attached to publicly disclose the scope of the invention.

1. Recording device, 11. Ejection head, 17. Liquid container, 21. Formation unit, 60. Pressure adjustment unit, 80. Atmospheric release unit

Claims (10)

a liquid chamber for receiving liquid from a liquid container and for storing the liquid to be supplied to a discharge means for discharging the liquid onto a recording medium, and a forming means for forming a pressure chamber adjacent to the liquid chamber;
a wall that separates the liquid chamber from the pressure chamber and that changes the volume of the liquid chamber by being displaced in response to the pressure of the pressure chamber;
a pressure adjusting means for adjusting the pressure of the pressure chamber to perform a replenishing operation of introducing liquid from the liquid container into the liquid chamber and a supplying operation of supplying liquid from the liquid chamber to the ejection means;
and an atmosphere opening means for opening the pressure chamber to the atmosphere in response to an operation related to replacement of the liquid container during the refilling operation, but not opening the pressure chamber to the atmosphere in response to the operation during the supplying operation.
A recording device characterized by: 2. The recording device according to claim 1,
The atmosphere opening means is
a differential pressure valve that switches between communication and cut-off between the first passage and the second passage depending on a pressure difference between the first passage and the second passage, the first passage communicating with the pressure chamber;
and a linkage valve that switches a third passage communicating with the second passage from a closed state to an open state in response to the operation.
A recording device characterized by: 2. The recording device according to claim 1,
the wall body is displaced so as to increase the volume of the liquid chamber when the pressure chamber is in a negative pressure state;
The pressure adjusting means is
In the replenishing operation, the pressure chamber is adjusted to a negative pressure state, and liquid is introduced from the liquid container into the liquid chamber;
In the supply operation, the pressure chamber is adjusted to a positive pressure state, and the liquid is supplied from the liquid chamber to the discharge means.
A recording device characterized by: 4. The recording device according to claim 3,
The atmosphere opening means is
a differential pressure valve that switches between communication and cut-off between the first passage and the second passage depending on a pressure difference between the first passage and the second passage, the first passage communicating with the pressure chamber;
a linkage valve that switches a third passage communicating with the second passage from a closed state to an open state in response to the operation,
the differential pressure valve connects the first passage and the second passage when the pressure in the first passage is lower than the pressure in the second passage;
A recording device characterized by: 2. The recording device according to claim 1,
an access cover for opening and closing the storage section of the liquid container;
The operation is an operation of opening the access cover.
A recording device characterized by: 3. The recording device according to claim 2,
The pressure adjusting means is
A pump and
a plurality of control valves provided between the pump and the pressure chamber;
an operation of pressurizing the pressure chamber and an operation of depressurizing the pressure chamber by the pump by a combination of opening and closing of the plurality of control valves;
Some components of the differential pressure valve and the plurality of control valves are integrated together.
A recording device characterized by: a liquid chamber for receiving liquid from a liquid container and for storing the liquid to be supplied to a discharge means for discharging the liquid onto a recording medium, and a forming means for forming a pressure chamber adjacent to the liquid chamber;
a wall that separates the liquid chamber from the pressure chamber and that changes the volume of the liquid chamber by being displaced in response to the pressure of the pressure chamber;
a pressure adjusting means for adjusting the pressure in the pressure chamber;
an atmosphere opening means for switching whether or not the pressure chamber is open to the atmosphere,
the wall body is displaced so as to increase the volume of the liquid chamber when the pressure chamber is in a negative pressure state;
The atmosphere opening means is
the pressure chamber is opened to the atmosphere in response to an operation related to replacement of the liquid container when the pressure chamber is in a negative pressure state, but the pressure chamber is not opened to the atmosphere in response to the operation when the pressure chamber is in a positive pressure state.
A recording device characterized by: 8. The recording device according to claim 7,
The pressure adjusting means is
A pump and
a plurality of control valves provided between the pump and the pressure chamber;
an operation of pressurizing the pressure chamber, an operation of depressurizing the pressure chamber, and an operation of opening the pressure chamber to the atmosphere are performed by the pump by combining opening and closing of the plurality of control valves;
A recording device characterized by: 2. The recording device according to claim 1,
a control unit that interrupts the refilling operation in response to an operation related to replacement of the liquid container during the refilling operation;
A recording device characterized by: 10. The recording device according to claim 9,
the control means performs processing related to a warning to a user when the replenishment operation is interrupted.
A recording device characterized by: