JP7639367B2 - Liquid ejection device - Google Patents

Description

The present invention relates to a liquid ejection device having an electrically driven valve that can selectively take either a connected state that connects an atmosphere communication passage for connecting a liquid storage chamber that is connected to a liquid ejection head with the outside, or a blocked state that blocks the atmosphere communication passage.

Patent document 1 describes an inkjet recording device in which ink supplied from an ink tank is stored in an ink buffer, and the ink is ejected from a print head on a carriage onto a recording medium to perform a recording operation. In this inkjet recording device, an air release solenoid valve that controls communication between the upper air layer in the ink buffer and the atmosphere is open while ink is being supplied. This allows the air in the upper part of the ink buffer to escape when ink is being supplied, and the ink in the ink buffer is not pressurized. Also, in this inkjet recording device, when purging, the air release solenoid valve is closed, and pressurized ink is supplied from the ink tank to perform the purging operation.

Publication number 01-040681

In this way, the above-mentioned Patent Document 1 describes opening the solenoid valve for venting to the atmosphere when supplying ink from the ink tank to the ink buffer, but does not describe the operation of the solenoid valve for venting to the atmosphere when directly injecting ink into the ink buffer. In other words, it does not describe the operation of the solenoid valve when a user provides an ink inlet for directly injecting ink into the ink buffer or a cover for covering the ink inlet. When a user opens the cover, sets an ink injector for injecting ink into the ink inlet, and injects ink into the ink buffer, if the solenoid valve is closed, internal pressure fluctuations occur in the space between the ink level in the ink buffer and the solenoid valve for venting to the atmosphere, causing internal pressure to rise. If such internal pressure fluctuations occur and the internal pressure rises above the withstand pressure value of the ink meniscus formed in the nozzle of the print head, the ink meniscus will break and ink will leak from the nozzle. On the other hand, it is possible to constantly open the solenoid valve for venting to the atmosphere to prevent internal pressure fluctuations in the ink buffer, but in this case, the ink in the ink buffer will evaporate.

The object of the present invention is to provide a liquid ejection device that can prevent liquid from leaking from the nozzle while also preventing liquid from evaporating from the liquid storage chamber.

The liquid ejection device of the present invention includes a liquid ejection head having a nozzle for ejecting liquid, a liquid storage chamber for storing liquid, a liquid inlet connecting the liquid storage chamber with the outside, an atmosphere communication passage for connecting the liquid storage chamber with the outside, and a liquid storage section having an electrically operated valve capable of selectively taking either a communication state for connecting the atmosphere communication passage or a blocking state for blocking the atmosphere communication passage, a liquid flow path connecting the liquid ejection head and the liquid storage chamber so that liquid can flow through them, a cover capable of opening and closing the liquid inlet, a liquid injection detection sensor that detects liquid injection from the liquid inlet into the liquid storage chamber when the cover is open and the liquid inlet is in an open state, and a control unit that controls the liquid ejection head and the valve. The control unit is capable of executing an injection process that controls the valve so that the valve changes from the blocked state to the communicating state when the liquid injection detection sensor detects liquid injection from the liquid inlet.

According to the liquid ejection device of the present invention, when the cover is open and the liquid inlet is open, it is possible to suppress fluctuations in the internal pressure of the liquid storage chamber by injecting liquid from the liquid inlet. This makes it difficult for the liquid meniscus formed in the nozzle to break, making it possible to suppress leakage of liquid from the nozzle. In addition, the valve is controlled to be in a communicating state when the liquid injection detection sensor detects liquid injection from the liquid inlet, making it possible to suppress evaporation of liquid in the liquid storage chamber.

1 is a schematic perspective view of a printer according to an embodiment of the present invention; 2 is a vertical cross-sectional view showing a schematic internal structure of the printer shown in FIG. 1 . 3A and 3B show the ink tank and the ink-jet head shown in FIG. 2, in which FIG. 3A is a front view and FIG. FIG. 2 is a block diagram showing the electrical configuration of the printer shown in FIG. 1 . 4 is a flowchart showing a recording operation of the printer. 5 is a flowchart showing the operation of the printer when injecting ink into an ink tank to refill it. 4 is a side view showing a state in which the ink filling part of the ink bottle is inserted into the ink filling port of the ink tank shown in FIG. 3. FIG. 13 is a side view showing a modified example of the printer, illustrating a state in which the ink filling part of the ink bottle is inserted into the ink filling port of the ink tank. 10 is a flowchart showing an operation when ink is injected into an ink tank to replenish the ink in a printer according to a modified example.

The printer 1 according to one embodiment of the present invention will be described below. The printer 1 is installed and used in the state shown in FIG. 1. In this embodiment, the three directions indicated by arrows in FIG. 1 are the up-down direction A1, the front-rear direction A2, and the left-right direction A3. The three directions shown in FIG. 1 are also reflected and shown in FIG. 2, FIG. 3, and FIG. 7.

<Outline of Printer 1>
As shown in FIG. 1, the printer 1 has a housing 11 having a generally rectangular parallelepiped shape. An opening 12 is formed in the approximate center of a front wall 11a of the housing 11. A paper feed tray 15 and a paper discharge tray 16 are provided in the opening 12 in two stages, one above the other. The paper feed tray 15 is configured to be insertable and removable in the front-rear direction A2 from the opening 12, that is, to be detachable from the housing 11. Paper P of a desired size (e.g., A4 size) is placed on the paper feed tray 15. The printer 1 can be connected to an external device such as a personal computer (hereinafter referred to as a PC). The printer 1 executes a printing operation based on printing data from the PC or the like.

As shown in FIG. 1, an operation unit 13 is provided on the upper part of the front wall 11a. The operation unit 13 is composed of buttons that are operated for various settings, a liquid crystal display that displays various information, and the like. In this embodiment, the operation unit 13 is composed of a touch panel that has the functions of both buttons and a liquid crystal display.

As shown in Figs. 1 and 2, the housing 11 has an opening/closing cover 14 that constitutes its ceiling portion. The opening/closing cover 14 is configured to be rotatable around a rotation axis (not shown) that is aligned with the left-right direction A3 at the rear end. By opening the opening/closing cover 14, an ink tank 61 (described below) is exposed, making it possible to inject ink into the ink tank 61 and refill it.

<Internal structure of printer 1>
Next, a description will be given of the internal structure of the printer 1. As shown in Fig. 2, the printer 1 includes a feed unit 20, a pair of transport rollers 35, a recording unit 40, a pair of paper discharge rollers 36, an ASF (Auto Sheet Feed) motor 20M (see Fig. 4), an LF (Line Feed) motor 35M (see Fig. 4), an opening/closing sensor 6 (see Fig. 4), and a control unit 5 (see Fig. 4).

As shown in FIG. 2, the feeding unit 20 feeds the paper P placed on the paper feed tray 15 to the transport path 25. The transport roller pair 35 transports the paper P fed by the feeding unit 20 to the recording unit 40. The recording unit 40 has, for example, an inkjet recording system configuration, and records an image on the paper P transported by the transport roller pair 35. The paper discharge roller pair 36 discharges the paper P recorded by the recording unit 40 to the paper discharge tray 16.

<Feeding section 20>
As shown in Fig. 2, the feeding unit 20 is provided above the paper feed tray 15. The feeding unit 20 has a paper feed roller 21 and an arm 22. The paper feed roller 21 is axially supported at the tip of the arm 22. The arm 22 is rotatably supported on a support shaft 22a, and is biased by a spring or the like to rotate the paper feed roller 21 downward so that the paper feed roller 21 comes into contact with the paper feed tray 15. The arm 22 is also configured to be able to retract upward when the paper feed tray 15 is attached or detached. The paper feed roller 21 is rotated by the power of the ASF motor 20M transmitted via a transmission mechanism (not shown), and the paper P loaded in the paper feed tray 15 is fed to the transport path 25.

<Paper Feed Tray 15>
2, the paper feed tray 15 has an inclined wall portion 15a. The inclined wall portion 15a guides the paper P placed on the paper feed tray 15 to the transport path 25 when the paper P is fed by the paper feed roller 21.

<Transport path 25>
2, the transport path 25 is formed inside the housing 11 and bends upward from the rear end of the paper feed tray 15 toward the front side of the printer 1. The paper P fed from the paper feed tray 15 is guided by the transport path 25 so as to make a U-turn from below to above, and reaches the recording unit 40.

<Pair of Conveying Rollers 35>
The pair of conveying rollers 35 includes a conveying roller 35a disposed on the lower side and a pinch roller 35b disposed on the upper side. The conveying roller 35a rotates by the power of the LF motor 35M transmitted through a transmission mechanism (not shown). The pinch roller 35b rotates together with the rotation of the conveying roller 35a. The conveying roller 35a and the pinch roller 35b cooperate to pinch the paper P from the vertical direction A1 and convey the paper P to the recording unit 40.

<Paper Discharge Roller Pair 36>
The pair of discharge rollers 36 has a discharge roller 36a disposed on the lower side and a spur roller 36b disposed on the upper side. The discharge roller 36a rotates by receiving the power of the LF motor 35M via a transmission mechanism (not shown). The spur roller 36b rotates together with the rotation of the discharge roller 36a. The discharge roller 36a and the spur roller 36b cooperate to hold the paper P in the vertical direction A1 and transport the paper P to the discharge tray 16.

<Recording unit 40>
2 and 3, the recording unit 40 has an inkjet head 41, an ink tank 61, a carriage 70, a moving mechanism 71, and a platen 17. The carriage 70 moves back and forth in a scanning direction (a left-right direction A3, a direction perpendicular to the transport direction of the paper P). The inkjet head 41 and the ink tank 61 are supported by the carriage 70. In other words, the printer 1 in this embodiment is a so-called on-carriage type in which the ink tank 61 and the inkjet head 41 are mounted on the carriage 70. The ink tank 61 in this embodiment is entirely located above the inkjet head 41. However, this is not limited thereto, and a part of the ink tank 61 may be located above the upper surface of the inkjet head 41, and the remaining part may be located below the upper surface.

<Ink Tank 61>
As shown in Fig. 3, the ink tank 61 has a tank body 62, a cap 63, and an electromagnetic valve 64. The tank body 62 has a substantially rectangular parallelepiped shape, and has an ink storage chamber 62a formed therein for storing ink. Black ink is stored in the ink storage chamber 62a. The tank body 62 is mainly made of a light-transmitting material (e.g., a transparent or translucent resin). This allows the user to visually check the amount of ink in the ink storage chamber 62a.

As shown in FIG. 3, the tank body 62 has a through hole 62c that penetrates its upper wall 62b. The through hole 62c is located in the center of the upper wall 62b in the left-right direction A3, slightly toward the front. A cylinder 66 is fitted into the through hole 62c. The cylinder 66 has an ink inlet 67 at its upper end. The ink inlet 67 is an opening that opens upward (i.e., toward the outside). The inner surface of the cylinder 66 defines an ink supply path 66a that extends from the ink inlet 67 to the ink storage chamber 62a. This allows the ink inlet 67 to communicate with the ink storage chamber 62a.

The cap 63 shown in FIG. 3 is made of, for example, a flexible resin, and can seal the ink inlet 67. The cap 63 can be attached to and detached from the upper end of the cylinder body 66 by a user operation, and closes or opens the ink inlet 67. More specifically, as shown in FIG. 3B, the cap 63 is supported by a support portion 62b1 at the rear end so as to be rotatable about a rotation axis 63a along the left-right direction A3. The support portion 62b1 is formed on the upper wall 62b of the tank body 62. The cap 63 is configured to be rotatable from a closed state (a state shown by a solid line in FIG. 3B) in which the cap 63 closes the ink inlet 67 to an open state (a state shown by a two-dot chain line in FIG. 3B) in which the cap 63 opens the ink inlet 67 by a user operation. The ink inlet 67 is normally closed by the cap 63, and is opened when ink is injected into the ink storage chamber 62a.

As shown in FIG. 3(b), the tank body 62 has an air communication port 62e that penetrates the rear side wall 62d and connects the ink storage chamber 62a to the outside. The air communication port 62e is located near the upper end of the rear side wall 62d. Also, as shown in FIG. 3, the tank body 62 has an upper index 62f1 and a lower index 62f2 formed on its front side wall 62f. The air communication port 62e only needs to be located above the upper index 62f1, and may be formed in the upper wall 62b, for example.

3, the upper indicator 62f1 has a linear shape extending left and right near the upper end on the outer surface of the front side wall 62f. The upper indicator 62f1 is disposed below the air communication port 62e in the vertical direction A1, as shown in FIG. 3(b). The upper indicator 62f1 is an example of an indicator that indicates the liquid level of the maximum amount of ink that can be stored in the ink storage chamber 62a. The lower indicator 62f2 has a linear shape extending left and right near the lower end on the outer surface of the front side wall 62f. The lower indicator 62f2 is an indicator that indicates the liquid level at which ink needs to be refilled, i.e., injected into the ink storage chamber 62a. The upper indicator 62f1 and the lower indicator 62f2 can also be realized by unevenness formed on the outer surface of the front side wall 62f, or by coloring with paint or the like.

As shown in FIG. 3B, the solenoid valve 64 is a known two-way solenoid valve and has a valve portion 64a and a solenoid portion 64b. The solenoid valve 64 is fixed to the upper wall 62b so as to be positioned above the upper indicator 62f1. The valve portion 64a is disposed in the ink storage chamber 62a and has an internal flow path (not shown) that communicates with the air communication port 62e and the ink storage chamber 62a, and a valve (not shown) that opens and closes the internal flow path. The solenoid portion 64b is disposed on the upper wall 62b and opens and closes the valve of the valve portion 64a. The solenoid valve 64 is controlled by the control unit 5, and the solenoid unit 64b is driven, so that the valve unit 64a selectively takes a communication state in which the atmosphere communication port 62e communicates with the ink storage chamber 62a (i.e., the valve opens the internal passage) and a blocking state in which the atmosphere communication port 62e blocks communication with the ink storage chamber 62a (i.e., the valve closes the internal passage).

As a modified example, the solenoid valve 64 may have the valve portion 64a connected outside the ink tank 61 so as to be able to communicate between the air communication port 62e and the outside. In this way, it is possible to selectively take a communication state in which the air communication port 62e is connected to the outside and a blocking state in which it is blocked from communication with the outside. The entire solenoid valve 64 may also be disposed in the ink storage chamber 62a. The solenoid valve 64 may also be fixed and installed on at least one of the front, rear, left, and right side walls other than the top wall 62b of the tank body 62, as long as the internal flow path of the valve portion 64a is connected so as to be able to communicate with the air communication port 62e.

In addition, the tank body 62 is formed with an outlet 62h that penetrates the bottom wall 62g and allows the ink in the ink storage chamber 62a to flow out to the inkjet head 41. The outlet 62h is located in the center of the bottom wall 62g in the left-right direction A3, near the front end.

<Open/close sensor 6>
The open/close sensor 6 is disposed on the upper wall 62b of the tank body 62 as shown in FIG. 3B. The open/close sensor 6 is a known mechanical switch, and is disposed at a position where it comes into contact with the cap 63 when the cap 63 opens the ink inlet 67. The open/close sensor 6 outputs a different signal to the control unit 5 when it comes into contact with the cap 63 and when it does not. That is, the open/close sensor 6 comes into contact with the cap 63 when the ink inlet 67 opens, and outputs a signal indicating that the ink inlet 67 is open to the control unit 5. On the other hand, when the cap 63 closes the ink inlet 67, the cap 63 does not come into contact with the open/close sensor 6. At this time, the open/close sensor 6 outputs a signal indicating that the ink inlet 67 is closed to the control unit 5. In this way, the open/close sensor 6 detects the ink inlet 67 being opened and ink being injected from the ink inlet 67.

<Inkjet head 41>
The inkjet head 41 has an internal flow path (not shown) to which black ink is supplied from the ink tank 61. As shown in Fig. 3B, the inkjet head 41 ejects ink from a plurality of nozzles 42 formed on a nozzle surface 41a, which is the lower surface of the inkjet head 41. More specifically, the plurality of nozzles 42 form a nozzle row that is aligned with the front-rear direction A2, that is, the transport direction of the paper P. Black ink is ejected from the plurality of nozzles 42.

As shown in FIG. 3, the inkjet head 41 is connected to the ink tank 61 via a connection member 69. The connection member 69 is formed with a communication passage (liquid flow passage) 69a that connects the outlet 62h to the internal flow passage of the inkjet head 41. This allows ink in the ink storage chamber 62a of the ink tank 61 to be supplied to the inkjet head 41.

<Platen 17>
The platen 17 is disposed below the inkjet head 41 and supports the paper P transported by the transport roller pair 35. The platen 17 is disposed in a portion of the reciprocating movement range of the carriage 70 through which the paper P passes. Since the width of the platen 17 is sufficiently larger than the maximum width of the paper P that can be transported, the paper P transported along the transport path 25 always passes over the platen 17.

<Moving mechanism 71>
As shown in FIG. 2, the movement mechanism 71 includes a pair of guide rails 72 and a belt transmission mechanism (not shown). The pair of guide rails 72 are disposed apart in the front-rear direction A2 and extend parallel to each other in the left-right direction A3. The carriage 70 is disposed so as to straddle the pair of guide rails 72. The carriage 70 is connected to a carriage motor 70M (see FIG. 4) via the belt transmission mechanism, and when the carriage motor 70M is driven, the belt transmission mechanism is driven. As a result, the carriage 70 moves in the scanning direction (left-right direction A3) along the pair of guide rails 72, and moves the inkjet head 41 between a maintenance position facing a maintenance cap (not shown) and a non-maintenance position not facing the maintenance cap.

The inkjet head 41 ejects ink from the nozzles 42 under the control of the control unit 5 based on the recording data. In other words, the inkjet head 41 scans the paper P as the carriage 70 moves back and forth in the left-right direction A3, and ejects ink from the nozzles 42 to record an image on the paper P transported on the platen 17. The printer 1 is provided with a linear encoder (not shown) having a number of light-transmitting sections (slits) arranged at intervals in the scanning direction. The carriage 70 is provided with a transmission-type position detection sensor (not shown) having a light-emitting element and a light-receiving element. The printer 1 is capable of recognizing the current position of the carriage 70 in the scanning direction from the count value of the light-transmitting section of the linear encoder detected by the position detection sensor while the carriage 51 is moving, and the rotation drive of the carriage motor 70M is controlled.

<Control unit 5>
As shown in Fig. 4, the control unit 5 includes a CPU (Central Processing Unit) 131, an ASIC (Application Specific Integrated Circuit) 135, and a memory 140. The CPU 131, the ASIC 135, and the memory 140 are connected by an internal bus 137. The memory 140 includes a ROM (Read Only Memory) 132, a RAM (Random Access Memory) 133, and an EEPROM (Electrically Erasable Programmable Read-Only Memory) 134. The ROM 132 stores programs for controlling various operations of the printer 1. The CPU 131 executes the programs using the RAM 133 and the EEPROM 134.

The ASIC 135 outputs control signals to the ASF motor 20M, LF motor 35M, carriage motor 70M, solenoid valve 64, inkjet head 41, etc., and controls their operation. For example, the control unit 5 controls the inkjet head 41, ASF motor 20M, LF motor 35M, carriage motor 70M, etc., based on recording data sent from an external device (e.g., a PC or smartphone), alternately performs a transport process and a recording process, and records an image, etc., on the paper P. The ASIC 135 also receives a signal from the open/close sensor 6.

The conveying process is a process in which the conveying roller pair 35 and the discharge roller pair 36 convey the paper P by a predetermined line feed amount. The control unit 5 controls the LF motor 35M to cause the conveying roller pair 35 and the discharge roller pair 36 to execute the conveying process. The recording process is a process in which the inkjet head 41 is controlled to eject ink droplets from the nozzle 42 while moving the carriage 70 along the left-right direction A3. The control unit 5 then stops the conveying of the paper P for a certain period between the current conveying process and the next conveying process, and executes the recording process while the conveying of the paper P is stopped. That is, in the recording process, the control unit 5 executes one pass in which ink droplets are ejected from the nozzle 42 while moving the carriage 70 to the right or left. As a result, one pass of image recording is executed on the paper P. The control unit 5 alternately executes the conveying process and the recording process, thereby making it possible to record an image in the entire area of the paper P where an image can be recorded. That is, the control unit 5 causes an image to be recorded on one sheet of paper P in multiple passes.

In this embodiment, the control unit 5 has one CPU and one ASIC, but the control unit 5 may include only one ASIC, which performs all the necessary processing, or it may include multiple ASICs, which share the necessary processing.

The memory 140 stores an ink count value, a reference value, and an ink threshold value. The ink count value is a value that is updated according to the amount of ink ejected from the inkjet head 41, and is stored in the RAM 133 or the EEPROM 134. The ink count value is calculated based on the recording data, which is data of the image to be recorded on the paper P.

More specifically, the control unit 5 refers to the recording data transmitted from an external device (e.g., a PC or a smartphone). The recording data is transmitted sequentially from the external device. Based on the recording data, the control unit 5 estimates the amount of ink to be ejected in the next recording process, and determines the ink count value corresponding to that amount of ink. In other words, based on the recording data, the control unit 5 determines the number of times ink droplets are ejected for each dot in the area to be ejected in the next recording process. This allows the number of times that all dots in the area are ejected to be calculated by adding up the number of times each dot is ejected. The calculated number of times that all dots in the area are ejected is the ink count value corresponding to the amount of ink to be ejected in the next recording process.

As described below, the ink count value is updated by being accumulated based on the recording data. The ink count value is also reset to an initial value at a predetermined timing (timing for ink refill) under the control of the control unit 5. The initial value is a preset value that is an initial value of the ink count value and is stored in the ROM 132 or the EEPROM 134. In this embodiment, the initial value is zero. Note that in this embodiment, the ink count value is counted up from an initial value of zero, but this is not limited to this. For example, the ink count value may be counted down from an initial value other than zero.

The ink threshold is a value that is compared with the consumption amount of ink stored in the ink storage chamber 62a, and is a value for determining the timing of opening the electromagnetic valve 64. In detail, the ink threshold is a value that is set in advance so that the difference between the ink count value and the reference value reaches the ink threshold before the ink meniscus formed in the nozzle 42 is damaged due to the increase in negative pressure in the ink storage chamber 62a. The ink threshold is a value that is determined by design for the ink meniscus withstand pressure, and is a value that indicates less than the withstand pressure value. In other words, when the difference does not reach the ink threshold, the negative pressure in the ink storage chamber 62a is not so large, and the ink meniscus formed in the nozzle 42 is not damaged. On the other hand, when the difference reaches the ink threshold, the ink meniscus formed in the nozzle 42 is easily damaged due to the increase in negative pressure. The ink threshold is also determined by the ratio of the volume of the ink space to the volume of the air space when the maximum amount of ink is stored in the ink storage chamber 62a. In this embodiment, the ink threshold value is stored in ROM 132 or EEPROM 134.

The recording operation of the printer 1 will now be described with reference to FIG. 5. In the printer 1, the inkjet head 41 is in the maintenance position during standby (when no recording operation is being performed). At this time, the solenoid valve 64 is in a blocking state that blocks communication with the atmosphere communication port 62e. This prevents the ink in the ink storage chamber 62a from evaporating.

A recording command is sent to the control unit 5 from the operation unit 13 of the printer 1 or an external device. The recording command includes a command to start a recording operation, information about the size of the paper P, and recording data to be recorded as an image on the paper P.

If the control unit 5 has not received a recording command in S1 (NO), it repeats S1 and waits, and if the control unit 5 has received a recording command (Yes), it proceeds to S2.

In S2, the control unit 5 drives the ASF 20M to feed the paper P from the paper feed tray 15. In S2, the control unit 5 also drives the LF motor 35M to transport the paper P and perform head alignment when the leading edge of the paper P reaches the transport roller pair 35. In head alignment, the control unit 5 stops the paper P at the image recording start position. The image recording start position is the position where the leading edge (downstream end) of the image recording area on the paper P in the transport direction faces the nozzle 42 that is located furthest downstream in the transport direction among the multiple nozzles 42.

In addition, in S2, the control unit 5 drives the carriage motor 70M to move the carriage 70 (inkjet head 41) from the maintenance position to the start position. The start position is the movement start position of the carriage 70 when the recording process (S7) is executed, and is determined based on the recording data. In S2, the operation from feeding the paper P to positioning the head and the movement operation of the carriage 70 are executed in parallel.

Next, in S3, the control unit 5 refers to the recording data and determines an ink count value that corresponds to the amount of ink to be ejected in the next pass to be executed, i.e., in the next recording process (S7). The control unit 5 then adds the determined ink count value to the ink count value currently stored in the memory 140, and stores the result of the addition in the memory 140 as a new ink count value. This updates the ink count value.

Next, in S4, the control unit 5 determines whether the difference between the ink count value and the reference value has reached the ink threshold value. Note that the control unit 5 stores the reference value in memory 140 as the ink count value stored in memory 140 at the time of the previous disconnection process in which the solenoid valve 64 changes from an open state to a disconnected state. Then, as the recording process in S7 described below is repeatedly executed and the ink count value is updated, the difference between the ink count value and the reference value may reach the ink threshold value. In this case (YES), proceed to S5. On the other hand, if the difference has not reached the ink threshold value (NO), proceed to S7.

Next, the control unit 5 executes a communication process in S5. That is, the control unit 5 drives the electromagnetic valve 64 to change from a blocked state to a connected state. This causes the atmosphere communication port 62e to communicate, and the ink storage chamber 62a to be open to the atmosphere. Therefore, the negative pressure in the ink storage chamber 62a decreases (the pressure is in equilibrium with the atmospheric pressure). As a result, damage to the ink meniscus formed in the nozzle 42 is suppressed, and it is possible to suppress air from entering the nozzle 42 and ink from leaking from the nozzle 42.

Next, the control unit 5 executes a cut-off process in S6. That is, the control unit 5 drives the electromagnetic valve 64 to change from a connected state to a cut-off state. This cuts off communication with the atmosphere communication port 62e, and closes the ink storage chamber 62a to the atmosphere. At this time, the control unit 5 stores the ink count value currently stored in the memory 140 in the memory 140 as a reference value.

Next, in S7, the control unit 5 executes the recording process. That is, the control unit 5 executes one pass to eject ink droplets from the nozzles 42 while moving the carriage 70 from the start position.

Next, in S8, the control unit 5 determines whether image recording on the paper P is complete based on the information about the size of the paper P and the recording data included in the recording command. If image recording on the paper P is not complete (NO), the process proceeds to S9, where a conveying process is performed. If image recording on the paper P is complete (YES), the process proceeds to S10.

Next, in S9, the control unit 5 drives the LF motor 35M to cause the transport roller pair 35 and the paper discharge roller pair 36 to transport the paper P a predetermined line feed amount. After this, the process returns to S3, and the control unit 5 determines an ink count value corresponding to the amount of ink to be ejected in the next recording process (S7), and adds the determined ink count value to the ink count value up to that point. Then, the processes of steps S4 to S8 are executed again. Note that the update of the ink count value in S3 may be executed in parallel with the transport process.

Next, in S10, the control unit 5 drives the LF motor 35M to cause the pair of conveying rollers 35 and the pair of paper discharge rollers 36 to convey the paper P and discharge it onto the paper discharge tray 16.

Next, in S11, the control unit 5 determines whether the image data included in the recording command contains image data that has not been recorded on the paper P, i.e., whether there is image recording for the next page. If there is image recording for the next page (YES), the process returns to S2. On the other hand, if there is no image recording for the next page (NO), the control unit 5 ends the series of recording operations.

Next, the operation of the printer 1 when injecting ink into the ink tank 61 to refill it will be described below with reference to Figures 6 and 7. As shown in Figure 6, in S101, the control unit 5 determines whether the ink inlet 67 is open or not.

The user refills the ink tank 61 with ink when the ink level in the ink tank 61 is near or below the lower indicator 62f2. The printer 1 may be provided with a liquid level sensor that detects whether the ink level in the ink tank 61 is empty, and the printer 1 may notify the user that the ink in the ink tank 61 is empty when the ink level is detected based on a detection signal from the liquid level sensor. The user may then refill the ink tank 61 with ink in response to this notification. The user may also periodically open the opening/closing cover to check the ink level in the ink tank 61, and refill the ink tank 61 with ink at an appropriate time.

When refilling the ink tank 61 with ink, prepare the ink bottle 90 shown in FIG. 7. The ink bottle 90 has a bottle body 91 in which black ink is stored, and an ink injection section 92 for injecting the ink in the bottle body 91 into the ink tank 61. The ink injection section 92 has an injection nozzle 92a that is inserted into the ink tank 61 through the ink inlet 67. Then, the user opens the opening/closing cover 14 and rotates the cap 63 of the ink tank 61 to change the ink inlet 67 from the closed state (the state shown by the solid line in FIG. 3B) to the open state shown in FIG. 7. This causes the cap 63 to come into contact with the opening/closing sensor 6, which outputs a signal to the control section 5 indicating that the ink inlet 67 is open.

In S101, if the ink inlet 67 is open (YES), the control unit 5 determines that ink is being injected from the ink inlet 67 into the ink storage chamber 62a, and proceeds to S102. On the other hand, if the ink inlet 67 is closed (NO), the control unit 5 determines that ink is not being injected from the ink inlet 67 into the ink storage chamber 62a, and repeats S101 and waits.

Next, the control unit 5 executes the injection process in S102. That is, the control unit 5 drives the electromagnetic valve 64 to change from a blocked state to a connected state. This opens the atmosphere communication port 62e, and the ink storage chamber 62a becomes open to the atmosphere. After opening the cap 63, the user inserts the injection nozzle 92a of the ink injection unit 92 into the ink injection port 67 at a predetermined timing. Then, ink from the ink bottle 90 is injected into the ink storage chamber 62a to replenish it. At this time, because the ink storage chamber 62a is open to the atmosphere, no internal pressure fluctuations occur in the ink storage chamber 62a even if the ink level in the ink storage chamber 62a rises.

Next, in S103, the control unit 5 determines whether the ink inlet 67 is closed. When the ink level reaches the upper indicator 62f1 due to the injection of ink into the ink storage chamber 62a, the user stops the ink injection and removes the injection nozzle 92a from the ink inlet 67. The user then rotates the cap 63 to change the ink inlet 67 from the open state to the closed state. After this, the user also closes the opening/closing cover 14. This causes the cap 63 to move away from the opening/closing sensor 6, which then outputs a signal to the control unit 5 indicating that the ink inlet 67 is closed.

In S103, if the ink inlet 67 is closed (YES), the control unit 5 determines that ink injection into the ink storage chamber 62a has finished, and proceeds to S104. On the other hand, if the ink inlet 67 is open (NO), the control unit 5 determines that ink has been injected into the ink storage chamber 62a, and repeats S103 and waits.

Next, in S104, the control unit 5 executes a cut-off process. That is, the control unit 5 drives the electromagnetic valve 64 to change from a connected state to a cut-off state, similar to S6 described above. This cuts off communication with the atmosphere communication port 62e, and closes the ink storage chamber 62a to the atmosphere. In this way, evaporation of ink in the ink storage chamber 62a is suppressed. At this time, the control unit 5 also resets the ink count value currently stored in the memory 140 to the initial value, and stores this ink count value in the memory 140 as a reference value. This is how the flow ends.

As described above, in the printer 1 of this embodiment, when the cap 63 (cover) is opened and the ink inlet 67 is opened in S101, the electromagnetic valve 64 is put into a communicating state by the injection process in S102. Therefore, it is possible to suppress the fluctuation in the internal pressure of the ink storage chamber 62a by the ink injection from the ink inlet 67. Therefore, the ink meniscus formed in the nozzle 42 is less likely to be damaged, and it is possible to suppress the leakage of ink from the nozzle 42. In addition, the electromagnetic valve 64 is controlled to be in a communicating state when the opening/closing sensor 6 (liquid injection detection sensor) detects the ink injection from the ink inlet 67, so that the evaporation of ink in the ink storage chamber 62a can be suppressed.

By using the open/close sensor 6, it is possible to detect whether ink is being injected through the ink inlet 67 when the cap 63 is open or closed.

In addition, when the open/close sensor 6 detects a change from an open state to a closed state in S103, the control unit 5 controls the electromagnetic valve 64 so that the electromagnetic valve 64 is switched to a blocked state in S104. This makes it possible to further prevent the ink in the ink storage chamber 62a from evaporating.

In addition, the cap 63 is used as a cover to open and close the ink inlet 67, making it possible to seal the ink inlet 67 when it is closed.

The inkjet head 41 and ink tank 61 are supported by the carriage 70, making the printer 1 an on-carriage type.

In the above-described embodiment, the open/close sensor 6 detects ink injection from the ink inlet 67 when the cap 63 is open and the ink inlet 67 is in an open state. However, as shown in FIG. 8, an insertion/removal sensor 206 may be provided on the cylinder 66 to detect the insertion/removal of the ink injection section 92 of the ink bottle 90 into the ink inlet 67, thereby detecting ink injection from the ink inlet 67. Note that parts similar to those in the above-described embodiment are indicated by the same reference numerals and descriptions thereof will be omitted.

In this modified example, the insertion/removal sensor 206 detects an insertion state (the state shown in FIG. 8) in which the injection nozzle 92a of the ink injection unit 92 is inserted into the ink injection port 67, and a removal state in which the injection nozzle 92a is removed from the ink injection port 67. More specifically, the insertion/removal sensor 206 is a proximity sensor fixed to the cylinder 66 so that the detection surface 206a forms part of the wall surface of the ink supply path 66a, and detects the injection nozzle 92a in the inserted state. The insertion/removal sensor 206 outputs different signals to the control unit 5 when it is in the inserted state and when it is in the removed state. This enables the control unit 5 to determine whether the injection nozzle 92a is in the inserted state inserted into the ink injection port 67 or in the removed state.

The operation of the printer 1 when injecting ink into the ink tank 61 in this modified example to refill it will be described below with reference to FIG. 9. As shown in FIG. 9, the control unit 5 determines in S201 whether or not it is in an inserted state. The user opens the opening/closing cover 14 and rotates the cap 63 of the ink tank 61 to change the ink inlet 67 from the closed state to the open state shown in FIG. 8. The user then inserts the injection nozzle 92a of the ink injection unit 92 into the ink inlet 67. As a result, the insertion/removal sensor 206 detects the inserted state of the injection nozzle 92a from the removed state, and outputs a signal indicating that state to the control unit 5.

In S201, if the ink is inserted (YES), the control unit 5 determines that ink is being injected from the ink inlet 67 into the ink chamber 62a, and proceeds to S202. On the other hand, if the ink is removed (NO), the control unit 5 determines that ink is not being injected from the ink inlet 67 into the ink chamber 62a, and repeats S201 and waits.

Next, the control unit 5 executes the injection process in S202. That is, the control unit 5 drives the electromagnetic valve 64 to change from a blocked state to a connected state, as in S102 described above. This opens the air communication port 62e, and the ink storage chamber 62a becomes open to the atmosphere. After inserting the injection nozzle 92a into the ink injection port 67, the user injects ink from the ink bottle 90 into the ink storage chamber 62a at a predetermined timing to refill it. At this time, because the ink storage chamber 62a is open to the atmosphere, no internal pressure fluctuations occur in the ink storage chamber 62a even if the ink level in the ink storage chamber 62a rises.

Next, in S203, the control unit 5 determines whether or not it is in the removed state. When the ink level reaches the upper indicator 62f1 due to the injection of ink into the ink storage chamber 62a, the user stops the injection of ink and removes the injection nozzle 92a from the ink injection port 67. The user then rotates the cap 63 to change the ink injection port 67 from the open state to the closed state. After this, the user also closes the opening and closing cover 14. When the injection nozzle 92a (ink injection unit 92) is thus removed from the ink injection port 67, the insertion/removal sensor 206 detects the removal state of the injection nozzle 92a from the inserted state, and outputs a signal to the control unit 5 indicating that it is in the removed state.

In S203, if the ink cartridge is in the removed state (YES), the control unit 5 determines that ink injection into the ink chamber 62a has been completed, and proceeds to S204. On the other hand, if the ink cartridge is in the inserted state (NO), the control unit 5 determines that ink has been injected into the ink chamber 62a, and waits while repeating S203.

Next, in S204, the control unit 5 executes a cut-off process. That is, similar to S104 described above, the control unit 5 drives the electromagnetic valve 64 to change from a connected state to a cut-off state. This cuts off communication with the atmosphere communication port 62e, and closes the ink storage chamber 62a to the atmosphere. In this way, evaporation of ink in the ink storage chamber 62a is suppressed. At this time, the control unit 5 also resets the ink count value currently stored in the memory 140 to the initial value, and stores this ink count value in the memory 140 as a reference value. This is how the flow ends.

According to this modified example, the insertion/removal sensor 206 detects whether the ink injection unit 92 is in an inserted state or a removed state with respect to the ink inlet 67, and when the insertion/removal sensor 206 detects a change from a removed state to an inserted state in S201, the control unit 5 controls the electromagnetic valve 64 to be in a communicating state in S202. Therefore, it is possible to suppress the internal pressure fluctuation of the ink storage chamber 62a by the ink injection from the ink inlet 67. Therefore, as in the above-mentioned embodiment, the ink meniscus formed in the nozzle 42 is less likely to be damaged, and it is possible to suppress the ink leakage from the nozzle 42. In addition, the electromagnetic valve 64 is controlled to be in a communicating state when the insertion/removal sensor 206 (liquid injection detection sensor) detects the ink injection from the ink inlet 67, so that the evaporation of the ink in the ink storage chamber 62a can be suppressed. In addition, by adopting the insertion/removal sensor 206, it is possible to detect the ink being injected from the ink inlet 67 in the inserted/removed state with respect to the ink inlet 67 of the ink injection unit 92.

In addition, when the insertion/removal sensor 206 detects a change from an inserted state to a removed state in S203, the control unit 5 controls the electromagnetic valve 64 so that the electromagnetic valve 64 is switched to a blocked state in S204. This makes it possible to further prevent the ink in the ink storage chamber 62a from evaporating.

As another modification, instead of the above-mentioned open/close sensor 6, a sensor that detects the open/close state of the opening/closing cover 14 that can open and close the ink inlet 67 may be provided in the printer. In this modification, the electromagnetic valve 64 may be controlled according to the open/close state of the opening/closing cover 14, similar to the open/close state of the above-mentioned cap 63. That is, when the sensor outputs a signal to the control unit 5 indicating that the opening/closing cover 14 is in the open state, the control unit 5 determines that ink is being injected from the ink inlet 67, and drives the electromagnetic valve 64 to change from the blocked state to the connected state. When the sensor outputs a signal to the control unit 5 indicating that the opening/closing cover 14 is in the closed state, the control unit 5 determines that the injection of ink into the ink storage chamber 62a has been completed, and drives the electromagnetic valve 64 to change from the connected state to the blocked state. This also provides the same effect as the above-mentioned embodiment.

As another modified example, a sensor (e.g., a float-type sensor or a line sensor) may be provided to detect the increase in ink in the ink storage chamber 42a due to the injection of ink from the ink inlet 67 into the ink storage chamber 42a, and the injection of ink from the ink inlet 67 may be detected. Then, the control unit 5 may control the electromagnetic valve 64 in the same manner as described above, based on a signal from the sensor. That is, when the sensor outputs a signal to the control unit 5 indicating that the ink in the ink storage chamber 42a has increased, the control unit 5 determines that ink has been injected from the ink inlet 67, drives the electromagnetic valve 64, and changes the state from the blocked state to the connected state. Also, when the sensor outputs a signal to the control unit 5 indicating that the ink in the ink storage chamber 42a has increased and then outputs a signal to the control unit 5 indicating that the ink increase has ended, the control unit 5 determines that the injection of ink into the ink storage chamber 62a has ended, drives the electromagnetic valve 64, and changes the state from the connected state to the blocked state. This also provides the same effect as the above embodiment.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the claims. In the above embodiment and modified example, the present invention is used in a monochrome printer, but it may be used in a color printer. In this case, the same effects as those described above can be obtained. The ink tank 61 may also have a communication passage connecting the atmosphere communication port 62e and the ink storage chamber 62a. In this case, the electromagnetic valve 64 only needs to be capable of selectively setting the atmosphere communication passage consisting of the communication passage and the atmosphere communication port 62e to a communication state in which the atmosphere communication passage communicates with the outside and a blocking state in which the atmosphere communication passage is blocked.

In the above embodiment, the ink tank 61 and the inkjet head 41 are mounted on the carriage 70, but the present invention can also be applied to a line-type inkjet head in which the carriage 70 is not provided and the inkjet head is fixed. In this case, too, the same effects as those described above can be obtained.

The present invention can also be applied to a liquid ejection device having a liquid ejection head that ejects liquids other than ink. The valve may be composed of an electric ball valve or an electric butterfly valve other than the electromagnetic valve 64. In other words, any valve that can be driven electrically may be used. The open/close sensor 6 may be any sensor (e.g., an optical sensor or a proximity sensor) that can detect the open/closed state of the cap 63. The insertion/removal sensor 206 may be any sensor (e.g., an optical sensor or a mechanical switch) that can detect the inserted/removed state of the injection nozzle 92a relative to the ink injection port 67.

1. Printer (liquid ejection device)
5 Control unit 6 Open/close sensor (liquid injection detection sensor, cover sensor)
14 Opening and closing cover (cover)
20 Feeding section (transport mechanism)
35 Transport roller pair (transport mechanism)
36 Paper discharge roller pair (transport mechanism)
41 Inkjet head (liquid ejection head)
42 Nozzle 61 Ink tank (liquid storage section)
62a Ink storage chamber (liquid storage chamber)
62e Atmosphere communication port (atmosphere communication passage)
63 Cap (cover)
64 Electromagnetic valve (valve)
67 Ink inlet (liquid inlet)
69a Communication path (liquid flow path)
70: Carriage 71: Moving mechanism 206: Insertion/removal sensor (liquid injection detection sensor)

Claims (8)

a liquid ejection head having a nozzle for ejecting liquid;
a liquid storage section having a liquid storage chamber for storing liquid, a liquid inlet connecting the liquid storage chamber to the outside, an atmosphere communication passage for connecting the liquid storage chamber to the outside, and an electrically operated valve capable of selectively taking either a communication state for connecting the atmosphere communication passage or a blocking state for blocking the atmosphere communication passage;
a liquid flow path that connects the liquid ejection head and the liquid storage chamber so that liquid can flow therethrough;
a cover capable of opening and closing the liquid inlet;
a liquid injection detection sensor that detects the injection of liquid from the liquid injection port into the liquid storage chamber when the cover is open and the liquid injection port is in an open state;
a control unit for controlling the liquid ejection head and the valve,
The control unit is
A liquid ejection device characterized in that, when the liquid injection detection sensor detects liquid injection from the liquid injection port, an injection process can be executed to control the valve so that the valve changes from the blocked state to the connected state. the liquid injection detection sensor is a cover sensor that detects the open state and a closed state of the liquid injection port with the cover closed,
The control unit is
2. The liquid ejection device according to claim 1, wherein, in the injection process, when the cover sensor detects that the cover has changed from the closed state to the open state, the valve is controlled so that the valve is in the communicating state. The liquid ejection device according to claim 2, characterized in that the control unit is further capable of executing a shutoff process to control the valve so that the valve assumes the shutoff state when the cover sensor detects the closed state from the open state. the liquid injection detection sensor is an insertion/removal sensor that detects an insertion state in which a liquid injection unit for injecting liquid into the liquid storage chamber is inserted into the liquid injection port and a removal state in which the liquid injection unit is removed from the liquid injection port,
The control unit is
2. The liquid ejection device according to claim 1, wherein, in the injection process, when the insertion/removal sensor detects the inserted state from the removed state, the valve is controlled so as to assume the communicating state. The liquid ejection device according to claim 4, characterized in that the control unit is further capable of executing a shutoff process to control the valve so that the valve assumes the shutoff state when the insertion/removal sensor detects the removal state from the insertion state. The liquid ejection device according to any one of claims 1 to 5, characterized in that the cover is a cap capable of sealing the liquid inlet. a conveying mechanism that conveys the recording medium in a conveying direction;
a carriage supporting the liquid ejection head and the liquid storage unit;
7. The liquid ejection device according to claim 1, further comprising a moving mechanism that moves a carriage in a scanning direction that intersects with the transport direction. The control unit is
a memory that stores a liquid count value, a reference value, and a liquid threshold value that indicates a pressure less than a withstand pressure value of a liquid meniscus formed in the nozzle, the liquid count value being updated in accordance with the amount of liquid ejected from the nozzle;
a storage process for storing the liquid count value when the valve changes from the communicating state to the blocking state in the memory as the reference value;
a determination process for determining whether or not a difference between the liquid count value and the reference value has reached the liquid threshold value,
A liquid ejection device according to any one of claims 1 to 7, characterized in that when it is determined in the judgment process that the difference has reached the liquid threshold value, the valve is controlled so that the valve temporarily opens and then closes the atmosphere communication passage.

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