Liquid discharge device

Abstract

To provide means that can shorten time till execution of maintenance processing from reception of the maintenance processing after a cartridge is installed to an installation case.SOLUTION: A liquid discharge device includes a step S12 of receiving maintenance processing after a step S10 of determining that a cartridge is installed to an installation case and receiving a high-level signal from a liquid level sensor; and a step S18 of starting the received maintenance processing based on a step S14 of receiving a low-level signal from the liquid level sensor.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to a liquid discharging device for discharging a liquid. [Background technology]

[0002] Conventionally, inkjet printers have been known that include a detachable main tank, a sub-tank that stores ink supplied from the attached main tank, and an image recording unit that records an image by ejecting the ink stored in the sub-tank (see, for example, Patent Document 1). In the inkjet printer, the internal spaces of the main tank and the sub-tank are open to the atmosphere. Therefore, when the main tank is attached to the inkjet printer, the difference in the head between the internal space of the main tank and the internal space of the sub-tank (hereinafter referred to as the "head difference") causes the ink to move so that the ink levels in the main tank and the sub-tank are at the same height. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-213162 Summary of the Invention [Problem to be solved by the invention]

[0004] The inkjet printer performs a maintenance process to discharge ink from the image recording unit by applying negative or positive pressure to the image recording unit. This maintenance process is intended to remove clogged flow paths and air bubbles in the image recording unit. The maintenance process may be performed, for example, based on a user's input, or periodically at predetermined time intervals or after a predetermined number of images have been recorded.

[0005] When the ink in the main tank is consumed, the main tank is replaced. When the main tank is replaced, the ink level in the subtank may be the same as the ink level in the main tank being replaced. Also, if the main tank being replaced is empty, the ink level in the subtank will be lower than the bottom of the ink chamber of the main tank being replaced. When a main tank containing an initial amount of ink is installed in an inkjet printer, the ink levels in the installed main tank and subtank will differ immediately after the main tank is installed. In other words, a head difference occurs. In order to eliminate the head difference, ink flows from the main tank to the subtank, and the ink levels in the main tank and subtank are aligned to the same height.

[0006] A maintenance process may be requested immediately after a main tank is installed in an inkjet printer. When a maintenance process is performed, ink flows out of the subtank before the ink level in the subtank has risen sufficiently. If the flow rate of ink flowing from the subtank to the image recording unit is greater than the flow rate of ink flowing from the main tank to the subtank, the ink level in the subtank will drop. As a result, air may enter the image recording unit from the subtank. Therefore, even if a maintenance process is requested immediately after a main tank is replaced, it may not be performed, and the printer may wait until the ink levels in the main tank and subtank are at the same height before executing the requested maintenance process.

[0007] However, if a long time passes between when the main tank is installed in the inkjet printer and the maintenance process is accepted and when the maintenance process is actually executed, the following problem may occur: The user may mistakenly believe that there is a problem with the acceptance or execution of the maintenance process. Furthermore, the user may have to wait a long time before the inkjet printer can be used after the maintenance process is completed.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a means for shortening the time from when a cartridge is attached to an attachment case and maintenance processing is accepted until the maintenance processing is actually performed. [Means for solving the problem]

[0009] (1) A liquid discharge device according to the present invention comprises a tank having a second liquid chamber connected to a cartridge having a first liquid chamber in which liquid is stored, a flow path having one end communicating with the second liquid chamber and the other end communicating with the first liquid chamber of the cartridge connected to the tank, a head communicating with the flow path, a liquid level sensor, and a controller. The controller discharges ink from the head based on a recording instruction, receives from the liquid level sensor a first signal output by the liquid level sensor in response to the position of the liquid level in the second liquid chamber being above a predetermined position, and after discharging ink from the head based on the recording instruction, receives from the liquid level sensor a second signal output by the liquid level sensor in response to the position of the liquid level in the second liquid chamber being below the predetermined position, and after receiving the second signal from the liquid level sensor, determines whether the cartridge has been attached to the mounting case, and after determining that the cartridge has been attached to the mounting case and receiving the second signal from the liquid level sensor, accepts a maintenance process to discharge the liquid stored in the second liquid chamber from the head, and executes the accepted maintenance process based on receiving the first signal from the liquid level sensor.

[0010] According to the above configuration, when a maintenance process is accepted after the cartridge is attached to the attachment case but before the first signal is received from the liquid level sensor, the maintenance process is not executed until the first signal is received from the liquid level sensor. This prevents air from entering the head from the second liquid chamber, and shortens the time from when the maintenance process is accepted to when it is executed.

[0011] (2) Preferably, the controller interrupts the maintenance process in progress in response to receiving the second signal from the liquid level sensor while executing the accepted maintenance process, and after interrupting the maintenance process in progress, executes the interrupted maintenance process in response to receiving the first signal from the liquid level sensor.

[0012] According to the above configuration, if the liquid level in the second liquid chamber falls below a predetermined position while a maintenance process is being performed due to reasons such as poor liquid flow from the first liquid chamber to the second liquid chamber, the maintenance process is interrupted, thereby preventing air from entering from the second liquid chamber toward the head.

[0013] (3) Preferably, the controller does not execute the maintenance process even if it receives the first signal from the liquid level sensor when a first elapsed time from the time it determines that the cartridge is attached to the attachment case to the time the first signal is received from the liquid level sensor reaches a first time, and executes the maintenance process when a second elapsed time from the time the first signal is received from the liquid level sensor reaches a second time.

[0014] According to the above configuration, when the flow rate of liquid from the first liquid chamber to the second liquid chamber is low, after the cartridge is attached to the attachment case and a maintenance process is requested, the timing to start the maintenance process can be delayed from when the first signal is received from the liquid level sensor, thereby preventing air from entering from the second liquid chamber toward the head.

[0015] (4) Preferably, the liquid discharge device further includes an alarm, and the controller activates the alarm in response to a third elapsed time from the time when it is determined that the cartridge is attached to the attachment case reaching a third time that is longer than the first time, and in response to receiving the second signal from the liquid level sensor without receiving the first signal.

[0016] According to the above configuration, when the flow rate of liquid from the first liquid chamber to the second liquid chamber becomes even smaller, the user is notified that there is an abnormality in the flow of liquid from the first liquid chamber to the second liquid chamber.

[0017] (5) A liquid discharge device according to the present invention includes a tank having a second liquid chamber connected to a cartridge having a first liquid chamber in which liquid is stored, a flow path having one end communicating with the second liquid chamber and the other end communicating with the first liquid chamber of the cartridge connected to the tank, a head communicated with the flow path, and a controller, wherein the controller discharges ink from the head based on a recording instruction, determines whether the cartridge is attached to the attachment case, and after discharging ink from the head based on the recording instruction, accepts a maintenance process for discharging liquid stored in the second liquid chamber from the head, determines that the cartridge is attached to the attachment case and accepts the maintenance process before the elapsed time from the time it was determined that the cartridge was attached to the attachment case reaches a standby time, and executes the accepted maintenance process on the condition that the elapsed time reaches the standby time.

[0018] According to the above configuration, when a maintenance process is accepted before the fourth time has elapsed after the cartridge is attached to the attachment case, air does not enter from the second liquid chamber toward the head, and the time from when the maintenance process is accepted to when it is executed can be shortened.

[0019] (6) The liquid discharging device further includes a temperature sensor, and the controller sets the waiting time to be longer as the temperature according to the signal received from the temperature sensor is lower.

[0020] According to the above configuration, if the flow rate from the first liquid chamber to the second liquid chamber is low due to low temperature and high viscosity of the liquid, the timing of executing the maintenance process after the cartridge is attached to the attachment case and the maintenance process is accepted will be delayed, thereby preventing air from entering from the second liquid chamber toward the head.

[0021] (7) A liquid discharge device according to the present invention comprises a tank having a second liquid chamber connected to a cartridge having a first liquid chamber in which liquid is stored, a flow path having one end communicating with the second liquid chamber and the other end communicating with the first liquid chamber of the cartridge connected to the tank, a head communicating with the flow path, an interface, and a controller. The controller discharges ink from the head based on a recording instruction, determines whether the cartridge is attached to the mounting case, and after discharging ink from the head based on the recording instruction, accepts a maintenance process to discharge liquid stored in the second liquid chamber from the head. In response to determining that the cartridge is attached to the mounting case, the controller reads the liquid volume Vc of the liquid stored in the first liquid chamber from the cartridge memory of the cartridge via the interface, and accepts the maintenance process if the read liquid volume Vc is less than a cartridge threshold value and before the elapsed time from the time it was determined that the cartridge was attached to the mounting case reaches a standby time, and executes the accepted maintenance process on the condition that the elapsed time reaches the standby time.

[0022] According to the above configuration, when the liquid volume Vc in the first liquid chamber of the cartridge attached to the attachment case is less than the cartridge threshold value and a maintenance process is accepted before the waiting time has elapsed, it is possible to prevent air from entering from the second liquid chamber toward the head. It is also possible to shorten the time from when the maintenance process is accepted until it is executed. If the liquid volume Vc in the first liquid chamber of the cartridge attached to the attachment case is equal to or greater than the cartridge threshold value, it is possible to execute the maintenance process immediately.

[0023] (8) Preferably, the controller determines the waiting time to be longer in inverse proportion to the liquid volume Vc, on condition that the liquid volume Vc is less than the cartridge threshold value.

[0024] According to the above configuration, the time from when the cartridge is mounted in the mounting case until the maintenance process is accepted and then executed can be shortened according to the liquid volume Vc.

[0025] (9) A liquid discharge device according to the present invention comprises a tank having a second liquid chamber connected to a cartridge having a first liquid chamber in which liquid is stored, a flow path having one end communicating with the second liquid chamber and the other end communicating with the first liquid chamber of the cartridge connected to the tank, a head communicating with the flow path, an interface, and a controller. The controller discharges ink from the head based on a recording instruction, determines whether the cartridge is attached to the mounting case, calculates the amount of liquid Vs stored in the second liquid chamber, discharges ink from the head based on the recording instruction, and then accepts a maintenance process to discharge the liquid stored in the second liquid chamber from the head.In response to determining that the cartridge is attached to the mounting case, the controller reads the amount of liquid Vc of the liquid stored in the first liquid chamber from the cartridge memory of the cartridge via the interface, and executes the accepted maintenance process on the condition that the amount of liquid Vs before the cartridge was attached to the mounting case is less than a first tank threshold value and that the total amount Vt, which is the sum of the amount of liquid Vs and the read amount of liquid Vc, is equal to or greater than a total amount threshold value.

[0026] According to the above configuration, it is possible to shorten the time from when the cartridge is attached to the attachment case and the maintenance process is accepted until it is executed.

[0027] (10) Preferably, the controller determines a flow rate Qc at which liquid flows from the first liquid chamber to the second liquid chamber based on the read liquid volume Vc, calculates a renewal liquid volume Vs by multiplying the flow rate Qc by the elapsed time since it was determined that the cartridge was attached to the attachment case and adding this liquid volume to the liquid volume Vs before the cartridge was attached to the attachment case, and performs the maintenance process if the total volume Vt is less than the total volume threshold and the renewal liquid volume Vs is greater than or equal to the first tank threshold.

[0028] According to the above configuration, when the total amount is less than the total amount threshold, it is possible to shorten the time from when the cartridge is attached to the attachment case and the maintenance process is accepted until the process is executed.

[0029] (11) Preferably, the controller calculates a second tank threshold by adding the first tank threshold to the liquid volume Vth obtained by multiplying the difference between the flow rate threshold and the flow rate Qc by the time during which the maintenance process is performed, provided that the flow rate Qc is less than a flow rate threshold, and performs the maintenance process if the updated liquid volume Vs is equal to or greater than the second tank threshold.

[0030] According to the above configuration, the time from when the cartridge is attached to the attachment case and the maintenance process is accepted until it is executed can be shortened according to the flow rate Qc.

[0031] (12) The liquid discharging device further includes a temperature sensor, and the controller determines the flow rate Qc such that the lower the temperature according to the signal received from the temperature sensor, the smaller the flow rate Qc.

[0032] According to the above configuration, when the temperature is low and the viscosity of the liquid is high, the flow rate from the first liquid chamber to the second liquid chamber decreases, and the determined flow rate Qc also decreases, thereby preventing air from entering from the second liquid chamber toward the head.

[0033] (13) The liquid discharge device further includes a pump and a cap connected to the pump, and when performing the maintenance process, the controller discharges liquid from the nozzles of the head by driving the pump with the cap covering the nozzles of the head. [Effects of the Invention]

[0034] According to the present invention, it is possible to shorten the time from when the cartridge is attached to the attachment case and the maintenance process is accepted until the maintenance process is executed. Also, by executing the maintenance process after the cartridge is attached to the attachment case, it is possible to reduce the risk of air entering from the second liquid chamber toward the head. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is an external perspective view of the printer 10, in which (A) shows a state in which the cover 87 is in the closed position, and (B) shows a state in which the cover 87 is in the open position. [Figure 2] FIG. 2 is a schematic cross-sectional view showing the internal structure of the printer 10. As shown in FIG. [Figure 3] FIG. 3 is a diagram showing a schematic configuration of the maintenance mechanism 70. As shown in FIG. [Figure 4] FIG. 4 is a vertical cross-sectional view of the attachment case 150. As shown in FIG. [Figure 5] FIG. 5 shows the structure of the cartridge 200, with (A) showing a front perspective view and (B) showing a vertical cross-sectional view. [Figure 6] FIG. 6 is a vertical cross-sectional view of the cartridge 200 attached to the attachment case 150. As shown in FIG. [Figure 7] FIG. 7 is a block diagram of the printer 10. [Figure 8] FIG. 8 is a flowchart of the maintenance process according to the first embodiment. [Figure 9]Figure 9(A) shows the state after all the ink stored in the liquid chamber 210 of the cartridge 200 has been consumed, and Figure 9(B) shows the state after the cartridge 200 has been attached to the mounting case 150 and ink is moving from the liquid chamber 210 to the liquid chamber 171. [Figure 10] FIG. 10 is a flowchart of the maintenance process according to the second embodiment. [Figure 11] FIG. 11 is a flowchart of the maintenance process according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0036] Each embodiment of the present invention will be described below. Note that each embodiment described below is merely an example of the present invention, and it goes without saying that each embodiment of the present invention can be modified as appropriate without departing from the spirit of the present invention. Furthermore, the up-down direction 7 is defined based on the use position in which the printer 10 is installed on a horizontal surface so that it can be used, the front-to-back direction 8 is defined with the surface of the printer 10 on which the opening 13 is formed as the front, and the left-to-right direction 9 is defined when viewing the printer 10 from the front. In each embodiment, in the use position, the up-down direction 7 corresponds to the vertical direction, and the front-to-back direction 8 and the left-to-right direction 9 correspond to the horizontal direction. The front-to-back direction 8 and the left-to-right direction 9 are perpendicular to each other.

[0037] [First embodiment] [Printer 10 Overview] The printer 10 according to this embodiment is an example of a liquid ejection device that records an image on a sheet using an inkjet recording method. The printer 10 has a roughly rectangular parallelepiped housing 14. The printer 10 may also be a so-called "multifunction device" that has functions such as a facsimile function, a scanning function, and a copying function.

[0038] As shown in Figures 1 to 3, inside the housing 14 are located a feed tray 15, a feed roller 23, a conveying roller 25, a head 21 having multiple nozzles 29, a platen 26 facing the head 21, a discharge roller 27, a discharge tray 16, an attachment case 150 to which the cartridge 200 is attached and detached, a tube 32 that connects the head 21 and the cartridge 200 attached to the attachment case 150, and a maintenance mechanism 70.

[0039] The printer 10 drives the feed roller 23 and the transport roller 25 to transport the sheet supported on the feed tray 15 to the position of the platen 26. Next, the printer 10 causes the head 21 to eject ink, which is supplied from the cartridge 200 mounted in the mounting case 150 through the tube 32, through the nozzles 29. This causes the ink to land on the sheet supported by the platen 26, recording an image on the sheet. The printer 10 then drives the discharge roller 27 to discharge the sheet on which the image has been recorded onto the discharge tray 16.

[0040] More specifically, the head 21 may be mounted on a carriage that moves back and forth in a main scanning direction that intersects with the direction of sheet transport by the transport rollers 25. The printer 10 may then cause the head 21 to eject ink through the nozzles 29 while moving the carriage from one side to the other in the main scanning direction. This causes an image to be recorded on a portion of the sheet facing the head 21. Next, the printer 10 may cause the transport rollers 25 to transport the sheet so that the area on which the next image is to be recorded faces the head 21. These processes are then alternately and repeatedly performed, thereby recording an image on one sheet.

[0041] In the following description, the discharge of ink from the nozzles 29 of the head 21 during image recording is referred to as "discharge," while the discharge of ink from the nozzles 29 of the head 21 during purging is not referred to as "discharge." However, "discharge" is a concept that is included in "discharge."

[0042] [Maintenance Organization 70] The maintenance mechanism 70 will be described below with reference to Figure 3. The maintenance mechanism 70 performs maintenance on the head 21. More specifically, the maintenance mechanism 70 performs a purging operation to suck out ink and air inside the nozzles 29, as well as foreign matter adhering to the nozzle surface. The ink and air inside the nozzles 29, and foreign matter adhering to the nozzle surface will hereinafter be referred to as "ink, etc." The ink, etc. sucked and removed by the maintenance mechanism 70 is stored in a waste liquid tank 74.

[0043] The maintenance mechanism 70 is located at a position (hereinafter also referred to as the "home position") that is off to one side in the main scanning direction (to the right) from the area where the head 21 records an image on a sheet. The maintenance mechanism 70 includes a cap 71, a tube 72, and a pump 73.

[0044] The cap 71 is made of rubber. The cap 71 faces the head 21 when the head 21 is located at the home position. The tube 72 connects the cap 71 to a waste liquid tank 74. The tube 72 runs from the cap 71 to the waste liquid tank 74 via a pump 73. The pump 73 is, for example, a rotary tube pump. Driven by a motor (not shown), the pump 73 sucks ink and the like from the nozzles 29 through the cap 71 and the tube 72 and discharges the ink into the waste liquid tank 74 via the tube 72.

[0045] The caps 71 are configured to be movable between a separated position, which is separated from the other caps 71 in the vertical direction 7, and a covering position by an elevating mechanism (not shown). In the covering position, the cap 71 comes into close contact with the nozzle surface of the head 21 in the home position and covers the nozzle surface. A plurality of nozzles 29 are open on the nozzle surface. In the separated position, the cap 71 is separated from the nozzle surface.

[0046] [Cover 87] As shown in FIG. 1, an opening 85 is formed on the front surface 14A of the housing 14 at the right end in the left-right direction 9. The housing 14 further includes a cover 87. The cover 87 is rotatable between a closed position (position shown in FIG. 1(A)) in which the opening 85 is closed, and an open position (position shown in FIG. 1(B)) in which the opening 85 is open. The cover 87 is supported by the housing 14, for example, near the lower end of the housing 14 in the up-down direction 7, so as to be rotatable about a rotation axis along the left-right direction 9. An attachment case 150 is located in an accommodation space 86 inside the housing 14 that extends beyond the opening 85.

[0047] [Cover Sensor 88] The printer 10 has a cover sensor 88 (see FIG. 7). The cover sensor 88 may be, for example, a mechanical sensor such as a switch that the cover 87 engages or disengages, or an optical sensor that blocks or transmits light depending on the position of the cover 87. The cover sensor 88 outputs a signal corresponding to the position of the cover 87 to the controller 130. More specifically, the cover sensor 88 outputs a low-level signal to the controller 130 when the cover 87 is in the closed position. On the other hand, the cover sensor 88 outputs a high-level signal, the signal strength of which is higher than the low-level signal, to the controller 130 when the cover 87 is in a position other than the closed position. In other words, the cover sensor 88 outputs a high-level signal to the controller 130 when the cover 87 is in the open position.

[0048] [Mounting Case 150] 4, the mounting case 150 includes a contact 152, a rod 153, an attachment sensor 154, a liquid level sensor 155, and a lock pin 156. The mounting case 150 can accommodate four cartridges 200 corresponding to the colors black, cyan, magenta, and yellow. That is, the mounting case 150 includes four contacts 152, four rods 153, four attachment sensors 154, and four liquid level sensors 155, one for each of the four cartridges 200. Note that the number of cartridges 200 that can be accommodated in the mounting case 150 is not limited to four, and may be one, or five or more.

[0049] The mounting case 150 is box-shaped and has an internal space that accommodates the mounted cartridge 200. The internal space of the mounting case 150 is defined by a top wall that defines the upper end, a bottom wall that defines the lower end, a rear wall that defines the rear end in the front-to-rear direction 8, and a pair of side walls that define both ends in the left-to-right direction 9. Meanwhile, an opening 85 is formed at a position facing the rear wall of the mounting case 150. That is, the opening 85 opens the internal space of the mounting case 150 to the outside of the printer 10 when the cover 87 is in the open position.

[0050] The cartridge 200 is inserted into the attachment case 150 through the opening 85 of the housing 14, and is removed from the attachment case 150. More specifically, the cartridge 200 passes through the opening 85 backward in the front-rear direction 8 and is attached to the attachment case 150. The cartridge 200 removed from the attachment case 150 passes through the opening 85 forward in the front-rear direction 8.

[0051] [Contact 152] The contact 152 is located on the top wall of the attachment case 150. The contact 152 protrudes downward from the top wall toward the internal space of the attachment case 150. When the cartridge 200 is attached to the attachment case 150, the contact 152 is located in a position where it comes into contact with an electrode 248 of the cartridge 200, which will be described later. The contact 152 is conductive and can be elastically deformed in the up-down direction 7. The contact 152 is electrically connected to the controller 130. The contact 152 is an example of an interface.

[0052] [Rod 153] The rod 153 protrudes forward from the rear wall of the mounting case 150. The rod 153 is located on the rear wall of the mounting case 150 above a joint 180, which will be described later. During the process of mounting the cartridge 200 to the mounting case 150, the rod 153 enters the atmospheric valve chamber 214 through an atmospheric vent port 221, which will be described later, of the cartridge 200. When the rod 153 enters the atmospheric valve chamber 214, the atmospheric valve chamber 214, which will be described later, is connected to the atmosphere.

[0053] [Wearing Sensor 154] The attachment sensor 154 is located on the top wall of the attachment case 150. The attachment sensor 154 is a sensor for detecting whether or not the cartridge 200 is attached to the attachment case 150. The attachment sensor 154 includes a light-emitting portion and a light-receiving portion spaced apart in the left-right direction 9. When the cartridge 200 is attached to the attachment case 150, a light-shielding rib 245 (described later) of the cartridge 200 is located between the light-emitting portion and the light-receiving portion of the attachment sensor 154. In other words, the light-emitting portion and the light-receiving portion of the attachment sensor 154 are located opposite each other, with the light-shielding rib 245 of the cartridge 200 attached to the attachment case 150 in between.

[0054] The wearing sensor 154 outputs a different signal (referred to as a "wearing signal" in the drawing) depending on whether or not light emitted from the light-emitting unit in the left-right direction 9 is received by the light-receiving unit. For example, the wearing sensor 154 outputs a low-level signal to the controller 130 when the received light intensity of the light received by the light-receiving unit is less than a threshold intensity. On the other hand, the wearing sensor 154 outputs a high-level signal, the signal intensity of which is higher than the low-level signal, to the controller 130 when the received light intensity of the light received by the light-receiving unit is equal to or greater than the threshold intensity.

[0055] [Liquid level sensor 155] The liquid level sensor 155 is a sensor for detecting whether a detection target 194 of the actuator 190 (described later) is located at the detection position. The liquid level sensor 155 includes a light-emitting element and a light-receiving element spaced apart in the left-right direction 9. In other words, the light-emitting element and the light-receiving element of the liquid level sensor 155 are positioned facing each other, sandwiching the detection target 194 located at the detection position. The liquid level sensor 155 outputs a different signal (referred to as a "liquid level signal" in the drawing) depending on whether light emitted from the light-emitting element is received by the light-receiving element. For example, the liquid level sensor 155 outputs a low-level signal to the controller 130 when the intensity of the light received by the light-receiving element is less than a threshold intensity. On the other hand, the liquid level sensor 155 outputs a high-level signal, the signal intensity of which is higher than the low-level signal, to the controller 130 when the intensity of the light received by the light-receiving element is equal to or greater than the threshold intensity. The low-level signal is an example of a first signal. The high-level signal is an example of the second signal.

[0056] [Lock pin 156] The lock pin 156 is a rod-shaped member that extends in the left-right direction 9 at the upper end of the internal space of the mounting case 150 and near the opening 85. Both ends of the lock pin 156 in the left-right direction 9 are fixed to a pair of side walls of the mounting case 150. The lock pin 156 extends in the left-right direction 9 across four spaces that can accommodate four cartridges 200. The lock pin 156 is used to hold the cartridge 200 attached to the mounting case 150 in the attached position shown in FIG. 6. When the cartridge 200 is attached to the mounting case 150, it engages with the lock pin 156.

[0057] [Tank 160] The printer 10 is equipped with four tanks 160 corresponding to the four cartridges 200, respectively. As the four tanks 160 have a generally common configuration, the following will describe only one tank 160. The tank 160 is located further rearward than the rear wall of the mounting case 150. As shown in FIG. 4, the tank 160 is composed of an upper wall 161, a front wall 162, a lower wall 163, a rear wall 164, and a pair of side walls (not shown). The front wall 162 is composed of multiple walls that are each offset in the front-to-rear direction 8. A liquid chamber 171 is formed inside the tank 160. The liquid chamber 171 is an example of a second liquid chamber.

[0058] Of the walls constituting the tank 160, at least the wall facing the liquid level sensor 155 is translucent. This allows light output by the liquid level sensor 155 to pass through the wall facing the liquid level sensor 155. At least a portion of the rear wall 164 may be a film welded to the end faces of the upper wall 161, the lower wall 163, and the side walls. The side walls of the tank 160 may be common to the mounting case 150, or may be independent from the mounting case 150. Furthermore, adjacent tanks 160 in the left-right direction 9 are separated by a partition wall (not shown).

[0059] The liquid chamber 171 is connected to an ink flow path (not shown) through the outlet 174. The lower end of the outlet 174 is defined by a lower wall 163 that defines the lower end of the liquid chamber 171. The outlet 174 is located lower in the up-down direction 7 than the joint 180 (more specifically, the lower end of the through-hole 184). The ink flow path (not shown) that is connected to the outlet 174 is connected to a tube 32 (see FIG. 2). This allows the liquid chamber 171 to communicate with the head 21 from the outlet 174 through the ink flow path and the tube 32. In other words, ink stored in the liquid chamber 171 is supplied to the head 21 from the outlet 174 through the ink flow path and the tube 32. The ink flow path and the tube 32 that are connected to the outlet 174 form a flow path with one end (outlet 174) that is connected to the liquid chamber 171 and the other end 33 (see FIG. 2) that is connected to the head 21.

[0060] The liquid chamber 171 is in communication with the atmosphere through an atmosphere communication chamber 175. More specifically, the atmosphere communication chamber 175 is in communication with the liquid chamber 171 through a through-hole 176 that penetrates the front wall 162. The through-hole 176 is covered with a semipermeable membrane 178. The semipermeable membrane 178 has the property of allowing the atmosphere to pass through but not allowing the ink to pass through. Alternatively, the semipermeable membrane 178 may have the property of providing greater resistance to the ink passing through the semipermeable membrane 178 than to the atmosphere passing through the semipermeable membrane 178. The atmosphere communication chamber 175 is in communication with the outside of the printer 10 through an atmosphere communication port 177 and a tube (not shown) connected to the atmosphere communication port 177. The atmosphere communication chamber 175 is in communication with the atmosphere through the atmosphere communication port 177 and a tube (not shown).

[0061] [Joint 180] As shown in FIG. 4, the joint 180 includes a needle 181 and a guide 182. The needle 181 is a tube having a flow path formed therein. The needle 181 protrudes forward from a front wall 162 that defines a liquid chamber 171. An opening 183 is formed at the front end of the needle 181. The internal space of the needle 181 communicates with the liquid chamber 171 via a through-hole 184 that penetrates the front wall 162. The guide 182 is a cylindrical member that is disposed around the needle 181. The guide 182 protrudes forward from the front wall 162 and has an open front end.

[0062] A valve 185 and a coil spring 186 are positioned in the internal space of the needle 181. The valve 185 is movable in the internal space of the needle 181 between a closed position and an open position along the front-to-rear direction 8. When the valve 185 is positioned at the closed position, it closes the opening 183. When the valve 185 is positioned at the open position, it opens the opening 183. The coil spring 186 biases the valve 185 in a direction that moves it from the open position to the closed position, i.e., forward in the front-to-rear direction 8.

[0063] [Actuator 190] As shown in FIG. 4, an actuator 190 is positioned in the liquid chamber 171. The actuator 190 is supported by a support member (not shown) disposed within the liquid chamber 171 so as to be rotatable in the directions of arrows 198 and 199. The actuator 190 can rotate between the position indicated by the solid line and the position indicated by the dashed line in FIG. 4. Furthermore, the actuator 190 is restricted from rotating in the direction of arrow 198 from the position indicated by the solid line by a stopper (not shown, for example, the inner wall of the liquid chamber 171). The actuator 190 includes a float 191, a shaft 192, an arm 193, and a detection target 194.

[0064] The float 191 is made of a material with a lower specific gravity than the ink stored in the liquid chamber 171. The shaft 192 protrudes from the right and left surfaces of the float 191 in the left-right direction 9. The shaft 192 is inserted into a hole (not shown) formed in a support member. This allows the actuator 190 to be supported by the support member so as to be rotatable around the shaft 192. The arm 193 extends substantially upward from the float 191. The detection target portion 194 is located at the protruding tip of the arm 193. The detection target portion 194 is a plate-shaped member that extends in the up-down direction 7 and the front-rear direction 8. The detection target portion 194 is made of a material or color that blocks light output from the light-emitting portion of the liquid level sensor 155.

[0065] When the ink level in the liquid chamber 171 is equal to or higher than a predetermined position P, the actuator 190 is rotated in the direction of arrow 198 by buoyancy and is held at the detection position indicated by the solid line in FIG. 4 by a stopper. On the other hand, when the ink level is lower than the predetermined position P, the actuator 190 rotates in the direction of arrow 199 in response to the drop in the ink level. This causes the detection target 194 to move to a position away from the detection position. In other words, the detection target 194 moves to a position corresponding to the amount of ink stored in the liquid chamber 171.

[0066] The predetermined position P is at the same height as the axial center of the needle 181 in the vertical direction 7, and at the same height as the center of an ink supply port 234 (described later). However, the predetermined position P is not limited to the above-mentioned position, as long as it is a position above the outflow port 174 in the vertical direction 7. As another example, the predetermined position P may be at the height of the upper or lower end of the internal space of the needle 181, or may be at the height of the upper or lower end of the ink supply port 234.

[0067] When the level of the ink stored in the liquid chamber 171 is equal to or higher than the predetermined position P, the light output from the light-emitting element of the liquid level sensor 155 is blocked by the detection target portion 194. As a result, the light from the light-emitting element does not reach the light-receiving element of the liquid level sensor 155, and so the liquid level sensor 155 outputs a low-level signal to the controller 130. On the other hand, when the level of the ink stored in the liquid chamber 171 is lower than the predetermined position P, the light output from the light-emitting element of the liquid level sensor 155 is not blocked by the detection target portion 194. As a result, the light from the light-emitting element reaches the light-receiving element of the liquid level sensor 155, and so the liquid level sensor 155 outputs a high-level signal to the controller 130. In other words, the controller 130 can detect whether the level of the ink in the liquid chamber 171 is equal to or higher than the predetermined position P based on the signal output from the liquid level sensor 155.

[0068] [Cartridge 200] The cartridge 200 is a container having a liquid chamber 210 (see FIG. 2) capable of storing liquid ink therein. The liquid chamber 210 is defined by, for example, a resin wall. As shown in FIG. 5(A), the cartridge 200 has a flat shape in which the dimensions along the up-down direction 7 and the front-rear direction 8 are greater than the dimensions along the left-right direction 9. The outer shapes of the cartridges 200 storing different colors of ink may be the same or different. At least a portion of the walls constituting the cartridge 200 is translucent. This allows the user to visually check the liquid level of the ink stored in the liquid chamber 210 of the cartridge 200 from outside the cartridge 200.

[0069] The cartridge 200 includes a housing 201 and a supply pipe 230. The housing 201 is composed of a rear wall 202, a front wall 203, an upper wall 204, a lower wall 205, and a pair of side walls 206 and 207. The rear wall 202 is composed of multiple walls that are each offset in the front-to-rear direction 8. The upper wall 204 is composed of multiple walls that are each offset in the up-down direction 7. The lower wall 205 is composed of multiple walls that are each offset in the up-down direction 7.

[0070] As shown in FIG. 5(B), a liquid chamber 210, an ink valve chamber 213, and an atmospheric valve chamber 214 are formed in the internal space of the cartridge 200. The liquid chamber 210 has an upper liquid chamber 211 and a lower liquid chamber 212. The upper liquid chamber 211, the lower liquid chamber 212, and the atmospheric valve chamber 214 are internal spaces of the housing 201. On the other hand, the ink valve chamber 213 is an internal space of the supply pipe 230. The liquid chamber 210 stores ink. The atmospheric valve chamber 214 connects the liquid chamber 210 to the outside of the cartridge 200. The liquid chamber 210 is an example of a first liquid chamber.

[0071] The upper liquid chamber 211 and the lower liquid chamber 212 of the liquid chamber 210 are separated in the up-down direction 7 by a partition wall 215 that separates the internal space of the housing 201. The upper liquid chamber 211 and the lower liquid chamber 212 are connected to each other by a through-hole 216 formed in the partition wall 215. The upper liquid chamber 211 and the atmospheric valve chamber 214 are separated in the up-down direction 7 by a partition wall 217 that separates the internal space of the housing 201. The upper liquid chamber 211 and the atmospheric valve chamber 214 are connected to each other by a through-hole 218 formed in the partition wall 217. The ink valve chamber 213 is connected to the lower end of the lower liquid chamber 212 via a through-hole 219.

[0072] The atmospheric valve chamber 214 is connected to the outside of the cartridge 200 through an atmospheric communication port 221 formed in the rear wall 202 at the top of the cartridge 200. That is, the atmospheric valve chamber 214 is a flow path having one end (through-hole 218) connected to the liquid chamber 210 (more specifically, the upper liquid chamber 211) and the other end (atmosphere communication port 221) connected to the outside of the cartridge 200. The atmospheric valve chamber 214 is connected to the atmosphere through the atmospheric communication port 221. A valve 222 and a coil spring 223 are also located in the atmospheric valve chamber 214. The valve 222 is movable in the front-rear direction 8 between a closed position and an open position. When the valve 222 is located in the closed position, it closes the atmospheric communication port 221. When the valve 222 is located in the open position, it opens the atmospheric communication port 221. The coil spring 223 biases the valve 222 in a direction that moves the valve 222 from the open position to the closed position, that is, backward in the front-rear direction 8.

[0073] The atmospheric valve chamber 214 is divided into two chambers in the front-rear direction 8 by a partition wall 224. The chamber located at the rear in the front-rear direction 8 is provided with a valve 222 and a coil spring 223, and is in communication with the outside through an atmosphere communication port 221. The chamber located at the front in the front-rear direction 8 is in communication with the upper liquid chamber 211 through a through-hole 218. A through-hole 225 is formed in the partition wall 224. The through-hole 225 connects the two chambers separated in the front-rear direction 8. The through-hole 225 is covered with a semipermeable membrane 226. The semipermeable membrane 226 has the property of allowing air to pass through but not allowing ink to pass through. Alternatively, the semipermeable membrane 226 may have the property of providing greater resistance to ink passing through the semipermeable membrane 226 than to air passing through the semipermeable membrane 226.

[0074] During the process of mounting the cartridge 200 in the mounting case 150, the rod 153 enters the atmosphere valve chamber 214 through the atmosphere communication port 221. The rod 153 that has entered the atmosphere valve chamber 214 moves the valve 222, which is in the closed position, forward against the biasing force of the coil spring 223. Then, the valve 222 moves to the open position, thereby connecting the upper liquid chamber 211 to the atmosphere. Note that the configuration for opening the atmosphere communication port 221 is not limited to the example described above. As another example, the rod 153 may break through a film that seals the atmosphere communication port 221.

[0075] The supply tube 230 protrudes rearward from the rear wall 202 at the bottom of the housing 201. The protruding end (i.e., the rear end) of the supply tube 230 is open. That is, the ink valve chamber 213 communicates between the liquid chamber 210, which is communicated through the through-hole 219, and the outside of the cartridge 200. The ink valve chamber 213 and the internal space of the needle 181 are an example of a flow path, one of which (the through-hole 219) is communicated with the liquid chamber 210 (more specifically, the lower liquid chamber 212) and the other of which (the through-hole 184, see FIG. 4) is communicated with the liquid chamber 171 of the tank 160. In addition, a packing 231, a valve 232, and a coil spring 233 are located in the ink valve chamber 213.

[0076] An ink supply port 234 is formed in the center of the packing 231, penetrating in the front-rear direction 8. The inner diameter of the ink supply port 234 is slightly smaller than the outer diameter of the needle 181. The valve 232 is movable in the front-rear direction 8 between a closed position and an open position. When the valve 232 is located in the closed position, it abuts against the packing 231 to close the ink supply port 234. When the valve 232 is located in the open position, it moves away from the packing 231 to open the ink supply port 234. The coil spring 233 biases the valve 232 in a direction that moves it from the open position to the closed position, i.e., backward in the front-rear direction 8. The biasing force of the coil spring 233 is greater than that of the coil spring 186.

[0077] During the process of mounting the cartridge 200 in the mounting case 150, the supply tube 230 enters the guide 182, and eventually the needle 181 enters the ink valve chamber 213 through the ink supply port 234. At this time, the needle 181 elastically deforms the packing 231 and comes into liquid-tight contact with the inner circumferential surface that defines the ink supply port 234. As the cartridge 200 is further inserted into the mounting case 150, the needle 181 moves the valve 232 forward against the biasing force of the coil spring 233. Furthermore, the valve 232 moves the valve 185, which protrudes from the opening 183 of the needle 181, backward against the biasing force of the coil spring 186.

[0078] 6, the ink supply port 234 and the opening 183 are opened, and the ink valve chamber 213 of the supply tube 230 communicates with the internal space of the needle 181. In other words, when the cartridge 200 is attached to the attachment case 150, the ink valve chamber 213 and the internal space of the needle 181 form a flow path that communicates the liquid chamber 210 of the cartridge 200 with the liquid chamber 171 of the tank 160.

[0079] Furthermore, when the cartridge 200 is attached to the attachment case 150, a portion of the liquid chamber 210 and a portion of the liquid chamber 171 overlap each other when viewed horizontally. As a result, the ink stored in the liquid chamber 210 moves to the liquid chamber 171 of the tank 160 through the connected supply pipe 230 and joint 180 due to the hydraulic head difference.

[0080] As shown in FIG. 5 , a protrusion 241 is formed on the upper wall 204. The protrusion 241 protrudes upward from the outer surface of the upper wall 204 and extends along the front-to-rear direction 8. The protrusion 241 has a locking surface 242 and an inclined surface 243. The locking surface 242 and the inclined surface 243 are located above the upper wall 204. The locking surface 242 faces forward in the front-to-rear direction 8 and extends in the up-down direction 7 and the left-to-right direction 9 (i.e., approximately perpendicular to the upper wall 204). The inclined surface 243 is inclined with respect to the upper wall 204 so as to face upward in the up-down direction 7 and rearward in the front-to-rear direction 8.

[0081] The locking surface 242 is a surface that comes into contact with the locking pin 156 when the cartridge 200 is attached to the attachment case 150. The inclined surface 243 is a surface that guides the locking pin 156 to a position where it comes into contact with the locking surface 242 during the process of attaching the cartridge 200 to the attachment case 150. When the locking surface 242 and the locking pin 156 come into contact with each other, the cartridge 200 is held in the attachment position shown in FIG. 6 against the biasing forces of the coil springs 186, 223, and 233.

[0082] A flat plate-shaped member is formed in front of the locking surface 242 and extending upward from the upper wall 204. The upper surface of this flat plate-shaped member is an operating portion 244 that is operated by the user when removing the cartridge 200 from the attachment case 150. When the cartridge 200 is attached to the attachment case 150 and the cover 87 is in the open position, the operating portion 244 can be operated by the user. When the operating portion 244 is pressed downward, the cartridge 200 rotates, and the locking surface 242 moves downward beyond the locking pin 156. As a result, the user can remove the cartridge 200 from the attachment case 150.

[0083] As shown in FIG. 5 , a light-shielding rib 245 is formed on the outer surface of the upper wall 204, behind the protrusion 241. The light-shielding rib 245 protrudes upward from the outer surface of the upper wall 204 and extends along the front-rear direction 8. The light-shielding rib 245 is formed of a material or color that blocks light output from the light-emitting portion of the attachment sensor 154. When the cartridge 200 is attached to the attachment case 150, the light-shielding rib 245 is located on the optical path from the light-emitting portion to the light-receiving portion of the attachment sensor 154. That is, the attachment sensor 154 outputs a low-level signal to the controller 130 in response to the cartridge 200 being attached to the attachment case 150. On the other hand, the attachment sensor 154 outputs a high-level signal to the controller 130 in response to the cartridge 200 not being attached to the attachment case 150. That is, the controller 130 can detect whether the cartridge 200 is attached to the attachment case 150 based on the signal output from the attachment sensor 154.

[0084] As shown in FIG. 5 , an IC board 247 is located on the outer surface of the top wall 204, between the light-shielding rib 245 and the protrusion 241 in the front-rear direction 8. Electrodes 248 are formed on the IC board 247. The IC board 247 also includes a memory (not shown). The electrodes 248 are electrically connected to the memory of the IC board 247. The electrodes 248 are exposed on the top surface of the IC board 247 so as to be electrically conductive with the contacts 152. That is, when the cartridge 200 is attached to the attachment case 150, the electrodes 248 are electrically conductive with the contacts 152. The controller 130 can read information from the memory of the IC board 247 through the contacts 152 and the electrodes 248, and can write information to the memory of the IC board 247 through the contacts 152 and the electrodes 248. The memory of the IC board 247 is an example of a cartridge memory.

[0085] The memory of the IC board 247 stores the ink amount Vc and identification information for identifying individual cartridges 200. Hereinafter, the information stored in the memory of the IC board 247 may be collectively referred to as "CTG information." The memory of the IC board 247 of a new cartridge 200 stores an initial ink amount Vc0 as the ink amount Vc. The initial ink amount Vc0 is the amount of ink stored in a new cartridge 200. Furthermore, "new" refers to a so-called unused product, a state in which the ink inside the cartridge 200 has never leaked out from the cartridge 200 after it has been manufactured and sold. An initial cartridge is one in which ink has not leaked out from the liquid chamber 210.

[0086] [Controller 130] 7, the controller 130 includes a CPU 131, a ROM 132, a RAM 133, an EEPROM 134, and an ASIC 135. The ROM 132 stores programs and the like used by the CPU 131 to control various operations. The RAM 133 is used as a storage area for temporarily recording data, signals, and the like used when the CPU 131 executes the programs, or as a working area for data processing. The EEPROM 134 stores setting information that should be retained even after the power is turned off. The ROM 132, RAM 133, and EEPROM 134 are examples of memory.

[0087] The ASIC 135 is used to operate the feed roller 23, the transport roller 25, the discharge roller 27, the head 21, and the pump 73. The controller 130 drives a motor (not shown) through the ASIC 135 to rotate the feed roller 23, the transport roller 25, and the discharge roller 27, and to drive the pump 73. The controller 130 also outputs a drive signal to a drive element of the head 21 through the ASIC 135, causing the head 21 to eject ink through the nozzles 29. The ASIC 135 can output a variety of drive signals depending on the size of the ink droplets to be ejected through the nozzles 29.

[0088] A display 17 and an operation panel 22 are also connected to the ASIC 135. The display 17 is a liquid crystal display, an organic EL display, or the like, and has a display surface that displays various information. The display 17 is an example of an alarm. However, specific examples of the alarm are not limited to the display 17, and may be a speaker, an LED lamp, or a combination of these. The operation panel 22 outputs an operation signal to the controller 130 in response to an operation by the user. The operation panel 22 may have, for example, a push button or a touch sensor superimposed on the display.

[0089] Furthermore, the ASIC 135 is electrically connected to a contact 152, a cover sensor 88, an attachment sensor 154, and a liquid level sensor 155. The controller 130 accesses the memory of the IC board 247 of the cartridge 200 attached to the attachment case 150 via the contact 152. The controller 130 detects the position of the cover 87 via the cover sensor 88. The controller 130 also detects whether the cartridge 200 is attached to the attachment case 150 via the attachment sensor 154. Furthermore, the controller 130 detects whether the ink level in the liquid chamber 171 is above a predetermined position P via the liquid level sensor 155.

[0090] The EEPROM 134 stores various information associated with each of the four cartridges 200 attached to the attachment case 150, in other words, associated with each of the tanks 160 communicating with the cartridges 200. The various information includes, for example, ink amounts Vc and Vs, which are an example of liquid amount, a function F, threshold values T1, T2, and T3, waiting times Tw1, Tw2, and Tw3, and identification information. Time T1 is an example of a first time. Waiting time Tw1 is an example of a second time. Time T2 is an example of a third time.

[0091] The ink amount Vc and identification information stored in the memory of the IC board 247 are information that is read by the controller 130 via the contacts 152 when the cartridge 200 is attached to the attachment case 150. The controller 130 stores the ink amount Vc and identification information read from the memory of the IC board 247 via the contacts 152 in the EEPROM 134. The function F may be stored in the ROM 132 instead of the EEPROM 134.

[0092] The ink volume Vc indicates the volume of ink stored in the ink chamber 210 of the cartridge 200. The ink volume Vs indicates the volume of ink stored in the ink chamber 171 of the tank 160. The ink volumes Vc and Vs are calculated, for example, using a function F. The function F is information indicating the correspondence between the total ink volume Vt, the ink volume Vc, and the ink volume Vc. The ink in the ink chamber 210 of the cartridge 200 and the ink in the ink chamber 171 of the tank 160 are in equilibrium when the positions of their ink liquid levels in the vertical direction 7 are aligned. In other words, in the equilibrium state, the movement of ink between the ink chamber 210 and the ink chamber 171 stops. For example, the relationship between the total ink volume Vt and the ink volume Vs can be approximated by the function F. Therefore, once the total ink volume Vt is calculated, the ink volume Vs and the ink volume Vc can be calculated. Note that the ink volume Vs and the ink volume Vc are not limited to the form of the function F and may be calculated using a table associated with each total volume Vt.

[0093] [Printer 10 Operation] The operation of the printer 10 according to this embodiment will be described with reference to Figure 8. The maintenance process shown in Figure 8 is executed by the CPU 131 of the controller 130. Note that each of the following processes may be executed by the CPU 131 reading out a program stored in the ROM 132, or may be realized by a hardware circuit mounted on the controller 130. The execution order of each of the following processes may be changed as appropriate without departing from the spirit of the present invention.

[0094] The controller 130 executes maintenance processing when a user inputs a command to execute maintenance processing on the operation panel 22. The controller 130 also executes maintenance processing at predetermined time intervals. When a user inputs a recording instruction to the printer 10, the controller 130 ejects ink from the head 21 to record an image. When the head 21 ejects ink, gas dissolved in the ink may form bubbles and enter the nozzles 29 of the head 21. Furthermore, an external force or the like may break the ink meniscus in the nozzles 29. As a result, the desired ink may not be ejected from each nozzle 29 of the head 21. If an abnormality occurs in any of the nozzles 29, the desired image may not be recorded on the sheet, or the quality of the recorded image may deteriorate.

[0095] When a malfunction occurs in any of the nozzles 29, a maintenance process is performed to restore the nozzles 29 to a normal state. In performing the maintenance process, the controller 130 positions the head 21 at the home position and covers the nozzle surface of the head 21 with a cap. Then, the controller 130 drives the pump 73 to suck ink and the like from the nozzles 29 of the head 21, thereby expelling air bubbles and the like from the nozzles 29.

[0096] As the head 21 discharges ink, the ink stored in the cartridge 200 attached to the attachment case 150 is consumed. When all of the ink stored in the liquid chamber 210 of the cartridge 200 attached to the attachment case 150 is consumed, the user replaces the cartridge 200 attached to the attachment case 150 with another cartridge 200. The other cartridge 200 may be a new cartridge 200 or a cartridge 200 in which a certain percentage of the ink has already been consumed.

[0097] As shown in FIG. 9(A), when all the ink stored in the liquid chamber 210 of the cartridge 200 attached to the attachment case 150 is consumed and some of the ink in the liquid chamber 171 of the tank 160 is also consumed, the ink level in the liquid chamber 171 falls below a predetermined position P. When the ink level in the liquid chamber 171 falls below the predetermined position P, the liquid level sensor 155 outputs a high-level signal. Upon receiving the high-level signal from the liquid level sensor 155, the controller 130 displays on the display 17 that the cartridge 200 attached to the attachment case 150 is empty. Seeing this message on the display 17, the user replaces the cartridge 200 attached to the attachment case 150.

[0098] As shown in FIG. 9B, when the cartridge 200 is replaced, a difference occurs between the ink level in the liquid chamber 210 of the replaced cartridge 200 and the ink level in the liquid chamber 171 of the tank 160. This difference is the so-called head difference, and due to this head difference, ink moves from the liquid chamber 210 to the liquid chamber 171 at a flow rate Qc. That is, ink flows into the liquid chamber 171 at the flow rate Qc. If a maintenance process is performed before the ink level in the liquid chamber 210 and the ink level in the liquid chamber 171 become equal, ink will flow out of the liquid chamber 171 at a flow rate Qp. If a maintenance process is performed when the flow rate Qp is greater than the flow rate Qc (flow rate Qp > flow rate Qc), the ink level in the liquid chamber 171 may drop and reach the outlet 174. When the ink level in the liquid chamber 171 reaches the outlet 174, gas enters the tube 32 and the head 21. In order to prevent gas from entering the tube 32 and the head 21, the controller 130 executes the following control when the user inputs a command to execute a maintenance process after replacing the cartridge 200.

[0099] 8 based on receiving a high-level signal from the attachment sensor 154. The controller 130 determines whether it subsequently receives a low-level signal from the attachment sensor 154 (S10). When the controller 130 receives a high-level signal from the attachment sensor 154 and then a low-level signal from the attachment sensor 154 (S10: Yes), the controller 130 stores the time in the EEPROM 134. Note that this time is essentially the time when the cartridge 200 was attached to the attachment case 150. Furthermore, when the controller 130 receives a low-level signal from the attachment sensor 154, the cartridge 200 is attached to the attachment case 150. Furthermore, when the controller 130 receives a high-level signal from the attachment sensor 154, the cartridge 200 is not attached to the attachment case 150.

[0100] Next, the controller 130 reads out CTG information such as identification information and ink amount Vc from the memory of the IC board 247 of the cartridge 200 attached to the attachment case 150 (S11). The controller 130 stores the read CTG information in the EEPROM 134.

[0101] The controller 130 then determines whether a command to execute a maintenance process has been input to the operation panel 22 (S12). If the controller 130 determines that a command to execute a maintenance process has not been input (S12: No), the controller 130 determines whether the signal received from the liquid level sensor 155 is a low level signal (S13). If the controller 130 determines that a low level signal has not been received from the liquid level sensor 155 (S13: No), the controller 130 executes S12. If the controller 130 determines that a low level signal has been received from the liquid level sensor 155 (S13: Yes), the controller 130 ends control including the maintenance process. Note that when the controller 130 receives a low level signal from the liquid level sensor 155, the ink level in the liquid chamber 171 is equal to or higher than the predetermined position P. Note that when the controller 130 receives a high level signal from the liquid level sensor 155, the ink level in the liquid chamber 171 is lower than the predetermined position P.

[0102] When the controller 130 determines that a command to execute a maintenance process has been input (S12: Yes), it determines whether the signal received from the liquid level sensor 155 is a low level signal (S14). As shown in Fig. 9(B), for example, when a new cartridge 200 is attached to the attachment case 150, ink starts to flow from the liquid chamber 210 to the liquid chamber 171. After some time has passed since the ink started to flow in, the ink level in the liquid chamber 171 reaches a predetermined position P, and the liquid level sensor 155 outputs a low level signal.

[0103] In response to determining that a low-level signal has not been received from the liquid level sensor 155 (S14: No), the controller 130 determines whether the time ΔT2 is equal to or greater than the time T2 (S15). The time ΔT2 is the time from the time when the low-level signal was received from the attachment sensor 154 to the current time. In response to determining that the time ΔT2 has not reached the time T2 (S15: No), the controller 130 executes S14. In response to determining that the time ΔT2 has reached the time T2 (S15: Yes), the controller 130 causes the display 17 to display a screen indicating that the maintenance process has resulted in an error (S16), and ends this control. The time T2 is, for example, preset to be longer than the time T1, which will be described later.

[0104] In response to receiving a low-level signal from the liquid level sensor 155 (S14: Yes), the controller 130 determines whether the time ΔT1 is equal to or greater than the time T1 (S17). The time ΔT1 is the time from when the low-level signal is received from the attachment sensor 154 (S10: Yes) to when the low-level signal is received from the liquid level sensor 155 (S14: Yes). In response to determining that the time ΔT1 is less than the time T1 (S17: No), the controller 130 starts a maintenance process (S18). That is, it starts a suction operation through the nozzles 29 of the head 21. The time ΔT1 is an example of a first elapsed time and a second elapsed time.

[0105] In response to determining that the time ΔT1 is equal to or greater than the time T1 (S17: Yes), the controller 130 waits for the time Tw1 (S19) and then starts the maintenance process (S18). Waiting for the time Tw1 is an example of the second elapsed time reaching the second hour. The time T1 is preset to be a time that is longer than the time required, for example, after the cartridge 200, which has the initial ink volume Vc0 stored in the liquid chamber 210, is mounted in the mounting case 150, for ink to flow from the liquid chamber 210 to the empty liquid chamber 171 and for the liquid level in the liquid chamber 171 to reach a predetermined position P.

[0106] When time ΔT1 is equal to or greater than time T1, it is estimated that the speed at which ink flows out from the liquid chamber 210 of the cartridge 200 to the liquid chamber 171 of the tank 160 (flow rate Qc) has slowed due to poor outflow or other reasons, and that this is taking longer than normal. Therefore, the flow rate Qc of ink into the liquid chamber 171 after the maintenance process has started is less than normal. In such a state, by waiting an additional time Tw1 after the liquid level in the liquid chamber 171 has reached the predetermined position P, a sufficient amount of ink is stored in the liquid chamber 171, and even if the maintenance process is then performed at the predetermined flow rate Qp, it is possible to prevent the liquid level in the liquid chamber 171 from reaching a position directly above the outlet 174. At the design stage of the printer 10, when the cartridge 200 is mounted with an initial ink volume Vc0 of ink stored in the liquid chamber 210 in a reference environment (temperature, humidity, etc.), the speed at which ink flows out from the liquid chamber of the cartridge 200 to the liquid chamber 171 of the tank 160 (flow rate Qc) and the speed at which ink flows out from the liquid chamber 171 to the tank 160 by the maintenance process (flow rate Qp) are designed to have the following relationship: In other words, the maintenance process is set so that the flow rate Qc after the liquid level sensor 155 outputs a low level signal is faster than the flow rate Qp after the liquid level sensor 155 outputs a low level signal.

[0107] After starting the maintenance process, the controller 130 determines whether or not a high-level signal has been received from the liquid level sensor 155 (S20). If the controller 130 determines that the maintenance process has ended (S21: Yes) without receiving a high-level signal from the liquid level sensor 155 (S20: No), the controller 130 ends control including the maintenance process.

[0108] After starting the maintenance process, the controller 130 stops the maintenance process (S22) in response to determining that a high-level signal has been received from the liquid level sensor 155 (S20: Yes). Also, in S22, the controller 130 stores the time at which the high-level signal was received from the liquid level sensor 155 in the RAM 133. Then, the controller 130 determines whether a low-level signal has been received from the liquid level sensor 155 (S23).

[0109] The maintenance process causes ink to flow out of the liquid chamber 171 into the tube 32 and the head 21. Meanwhile, ink flows into the liquid chamber 171 from the liquid chamber 210 of the cartridge 200. If the flow rate Qp at which ink flows out of the liquid chamber 171 is greater than the flow rate Qc at which ink flows into the liquid chamber 171, the liquid level in the liquid chamber 171 may drop and fall below a predetermined position P. When the liquid level in the liquid chamber 171 falls below the predetermined position P, the liquid level sensor 155 outputs a high-level signal to the controller 130. If the situation continues in which the flow rate Qp at which ink flows out of the liquid chamber 171 is greater than the flow rate Qc at which ink flows into the liquid chamber 171, the liquid level in the liquid chamber 171 may eventually reach a position immediately above the outlet 174. Therefore, when the controller 130 receives a high-level signal after starting the maintenance process (S20: Yes), it temporarily stops the maintenance process. While the maintenance process is temporarily stopped, the ink level rises in the liquid chamber 171. This prevents the ink level in the liquid chamber 171 from eventually dropping to near the outlet 174 as the maintenance process continues.

[0110] In response to receiving a low-level signal from the liquid level sensor 155 (S23: Yes), the controller 130 waits for a time Tw2 (an example of a second time) (S24) and then resumes the stopped maintenance process (S25). When the maintenance process starts, the ink level in the liquid chamber 171 begins to drop, so by waiting for a further time Tw2 after the liquid level in the liquid chamber 171 reaches a predetermined position P, a sufficient amount of ink can be stored in the liquid chamber 171. Then, the controller 130 executes S20.

[0111] In response to determining that a low-level signal has not been received from the liquid level sensor 155 (S23: No), the controller 130 determines whether the time ΔT3 has reached time T3 (an example of a third time) (S26). The time ΔT3 is the time from the time when a high-level signal was received from the attachment sensor 154 (the time when S19: Yes) to the current time (the time when the process of S26 is executed). In response to determining that the time ΔT3 has not reached time T3 (S26: No), the controller 130 executes S23. In response to determining that the time ΔT3 has reached time T3 (S26: Yes), the controller 130 causes the display 17 to display a screen indicating that the maintenance process has resulted in an error (S27), and ends control including the maintenance process. The time T3 is, for example, preset to be longer than time T1, which will be described later.

[0112] [Effects of the first embodiment] According to the first embodiment, when the controller 130 receives a maintenance request after the cartridge 200 is attached to the attachment case 150 but before receiving a low-level signal from the liquid level sensor 155, the controller 130 does not execute the maintenance request until it receives a low-level signal from the liquid level sensor 155. This prevents air from entering the tube 32 or the head 21 from the liquid chamber 171, and shortens the time from when the controller 130 receives the maintenance request until when it executes it.

[0113] Furthermore, if the ink level in the liquid chamber 171 falls below a predetermined position P while the controller 130 is performing maintenance processing due to factors such as poor ink flow from the liquid chamber 210 to the liquid chamber 171, the controller 130 temporarily stops the maintenance processing. This prevents air from entering the tube 32 or the head 21 from the liquid chamber 171.

[0114] Furthermore, when the ink flow rate Qc from the liquid chamber 210 to the liquid chamber 171 is small, the controller 130 waits for a time Tw1 after the cartridge 200 is attached to the attachment case 150 and a maintenance process is received. This causes the timing to start the maintenance process to be later than when the controller 130 receives a low-level signal from the liquid level sensor 155. This prevents air from entering the tube 32 or the head 21 from the liquid chamber 171.

[0115] Furthermore, when the ink flow rate Qc from the liquid chamber 210 to the liquid chamber 171 is even smaller, the controller 130 notifies the user via the display 17 that there is an abnormality in the outflow of ink from the liquid chamber 210 to the liquid chamber 171.

[0116] [Second embodiment] The second embodiment will be described below. The printer according to the second embodiment does not include the liquid level sensor 155 of the printer 10 according to the first embodiment, but includes a temperature sensor. The temperature sensor outputs an electrical signal to the controller 130 according to the ambient temperature at which the printer is set. The EEPROM 134 also stores a threshold value C0 for the predetermined temperature and times T4 and T5 set as the standby time Tk. In the second embodiment, when a maintenance process is received after the cartridge 200 is replaced, a different control is executed than in the first embodiment. The remaining printer configuration is the same as that of the printer 10 according to the first embodiment, and therefore detailed description thereof will be omitted.

[0117] As in the first embodiment, the controller 130 executes the following control when all the ink in the liquid chamber 210 of the cartridge 200 mounted in the mounting case 150 of the printer 10 is consumed and the cartridge 200 is removed from the mounting case 150.

[0118] 10, the controller 130 receives a high-level signal from the mounting sensor 154, and then determines whether it has received a low-level signal from the mounting sensor 154 (S30). When the controller 130 receives a low-level signal from the mounting sensor 154, the cartridge 200 is mounted in the mounting case 150. When the controller 130 receives a high-level signal from the mounting sensor 154, the cartridge 200 is not mounted in the mounting case 150.

[0119] Next, the controller 130 reads out CTG information such as identification information and ink amount Vc from the memory of the IC board 247 of the cartridge 200 attached to the attachment case 150 (S31). The controller 130 stores the read CTG information in the EEPROM 134.

[0120] Then, the controller 130 determines whether a command to execute a maintenance process has been input to the operation panel 22 (S32). If the controller 130 determines that a command to execute a maintenance process has not been input (S32: No), the controller 130 determines whether the standby time Tk has elapsed since receiving a low-level signal from the mounting sensor 154 (S33). If the controller 130 determines that the standby time Tk has not elapsed (S33: No), the controller 130 executes S32. If the controller 130 determines that the standby time Tk has elapsed (S33: Yes), the controller 130 ends this control.

[0121] When the controller 130 determines that a command to execute a maintenance process has been input via the operation panel 22 (S32: Yes), it determines whether the initial ink amount Vc0 has been read from the memory of the IC board 247 as the ink amount Vc (S34). The initial ink amount Vc0 is stored as the ink amount Vc in the memory of the IC board 247 of a new cartridge 200. When the cartridge 200 is used, for example, after the cartridge 200 is mounted in the mounting case 150, and ink is discharged through the head 21 for image recording, maintenance, or the like, the controller 130 updates the ink amount Vc stored in the memory of the IC board 247. Therefore, a cartridge 200 for which the controller 130 has read the initial ink amount Vc0 as the ink amount Vc stored in the memory of the IC board 247 is a new cartridge. Note that instead of the value of the ink amount Vc, a value or information such as a flag indicating that the cartridge is a new cartridge in the CTG information may be stored in the memory of the IC board 247. In this case, the controller 130 may determine whether or not the cartridge is new by reading out the above values and information stored in the memory of the IC board 247. The initial ink amount Vc0 is an example of a cartridge threshold value.

[0122] The controller 130 executes maintenance processing (S39) in response to determining that the ink amount Vc stored in the memory of the IC board 247 is the initial ink amount Vc0 (S34: Yes). When a new cartridge 200 is attached to the attachment case 150, ink flows from the liquid chamber 210 to the liquid chamber 171. The flow rate Qc at this time is the fastest among cartridges 200 of the same type because the head difference, which is the difference between the liquid level in the liquid chamber 171 of the tank 160 and the liquid level in the liquid chamber 210 of the cartridge 200, is the largest. The reason for this is explained below.

[0123] The initial ink volume Vc0 is an ink volume that can be set when the cartridge 200 is manufactured, and can be standardized within a predetermined range, so the flow rate Qc can also be set within a predetermined range. That is, in a new cartridge 200, the flow rate Qc is set to be larger than the flow rate Qp of ink flowing out of the liquid chamber 171 during maintenance processing. This prevents the ink level in the liquid chamber 171 from dropping, even if maintenance processing is performed when a new cartridge 200 is attached to the mounting case 150 and ink is moving from the liquid chamber 210 to the liquid chamber 171.

[0124] On the other hand, suppose that a cartridge 200 that is not new, i.e., a cartridge 200 that has already been used and in which the amount of ink Vc stored in the liquid chamber 210 is less than the initial ink amount Vc0, is attached to the attachment case 150. When a new cartridge 200 is attached to the attachment case 150, the head difference between the liquid chamber 210 and the liquid chamber 171 is smaller than the head difference between the liquid chamber 210 and the liquid chamber 171 when a new cartridge 200 is attached. The smaller the head difference, the smaller the flow rate Qc. As a result, there is a risk that the flow rate Qc will be smaller than the flow rate Qp of ink flowing out of the liquid chamber 171 during the maintenance process. If the flow rate Qc is smaller than the flow rate Qp, there is a risk that the liquid level in the liquid chamber 171 will drop during the maintenance process and reach a position immediately above the outlet 174. Therefore, when a new cartridge 200 is attached to the attachment case 150, the controller 130 will not immediately execute the maintenance process even if it is accepted.

[0125] If the ink amount Vc read from the memory of the IC board 247 is not the initial ink amount Vc0 (S34: No), the controller 130 determines whether the temperature output by the temperature sensor is less than the threshold value C0 (S35). If the controller 130 determines that the temperature output by the temperature sensor is equal to or greater than the threshold value C0 (S35: No), the controller 130 sets the standby time Tk to time T4 (S36). On the other hand, if the controller 130 determines that the temperature output by the temperature sensor is less than the threshold value C0 (S35: Yes), the controller 130 sets the standby time Tk to time T5. Time T5 is longer than time T4.

[0126] If the environmental temperature in which the printer 10 is installed is low, it is estimated that the temperature of the ink stored in the cartridge 200 attached to the attachment case 150 will also be low. As the temperature decreases, the viscosity of ink increases. Therefore, as the environmental temperature decreases, the flow rate Qc of ink from the liquid chamber 210 to the liquid chamber 171 tends to decrease. Therefore, if the temperature C is less than the threshold value C0, the controller 130 sets the standby time Tk to a time T5 that is longer than the time T4.

[0127] Then, after waiting for the standby time Tk (S38), the controller 130 executes the maintenance process (S39). During the standby time Tk, ink flows out from the liquid chamber 210 of the cartridge 200 to the liquid chamber 171 of the tank 160, causing the liquid level of the ink stored in the liquid chamber 171 to rise. As the standby time Tk becomes longer, the liquid level of the ink stored in the liquid chamber 171 becomes higher. In other words, even if the ink level in the liquid chamber 171 drops during the maintenance process, the risk of the ink level reaching directly above the outlet 174 is reduced.

[0128] [Effects of the second embodiment] According to the second embodiment, when the controller 130 receives a request to execute a maintenance process after the cartridge 200 is attached to the attachment case 150, it reads out the ink amount Vc stored in the memory of the IC board 247. If the read ink amount Vc is not the initial ink amount Vc0, the controller 130 executes the maintenance process after the waiting time Tk has elapsed. This makes it possible to shorten the time until the maintenance process is executed without air entering the tube 32 from the liquid chamber 171. On the other hand, when the controller 130 receives a request to execute a maintenance process after the cartridge 200 storing ink at the initial ink amount Vc0 is attached to the attachment case 150, the controller 130 immediately executes the maintenance process without waiting for the waiting time Tk to elapse.

[0129] Furthermore, because the environmental temperature in which the printer 10 is installed is low and the viscosity of the ink is high, the flow rate Qc from the liquid chamber 210 to the liquid chamber 171 is small. When the environmental temperature is below the threshold, the controller 130 sets the waiting time Tk after the cartridge 200 is mounted in the mounting case 150 until the maintenance process is performed to a time T5 that is longer than the time T4, and therefore the timing at which the maintenance process is performed is delayed. This prevents air from entering the tube 32 from the liquid chamber 171 during the maintenance process.

[0130] [Modification of the second embodiment] In the second embodiment, when the ink amount Vc read from the memory of the IC board 247 is not the initial ink amount Vc0, the controller 130 may determine the waiting time Tk so that it increases in inverse proportion to the read value of the ink amount Vc. In other words, the greater the amount of ink in the liquid chamber 210 of the cartridge 200, the shorter the waiting time Tk, and the smaller the amount of ink in the liquid chamber 210, the longer the waiting time Tk. For example, the controller 130 determines the time Tk based on a table or function in which times T4 and T5 increase in inverse proportion to the ink amount Vc.

[0131] Furthermore, in the second embodiment, the determination (S34) of whether the ink amount Vc read from the memory of the IC board 247 is the initial ink amount Vc0 may be omitted. In other words, regardless of the value of the ink amount Vc read from the IC board 247, the controller 130 may wait for the waiting time Tk after the cartridge 200 is replaced, and then execute the maintenance process.

[0132] [Third embodiment] The third embodiment will be described below. Like the printer according to the second embodiment, the printer according to the third embodiment does not include a liquid level sensor 155. The EEPROM 134 also stores a threshold flow rate Qp (an example of a flow rate threshold), a maintenance process execution time Tp, a tank threshold Vth1 (an example of a first tank threshold), a threshold Vth2 (an example of a total amount threshold), and a function or table indicating the relationship between the ink amount Vc and the flow rate Qc. In the third embodiment, when a maintenance process is accepted after the cartridge 200 has been replaced, control different from that of the first and second embodiments is executed. The remaining printer configuration is the same as that of the printer 10 according to the first embodiment, and therefore detailed description thereof will be omitted.

[0133] As in the first embodiment, the controller 130 executes the following control when it receives a request from the user to perform maintenance processing after all the ink in the liquid chamber 210 of the cartridge 200 mounted in the mounting case 150 of the printer 10 has been consumed and the cartridge 200 has been removed from the mounting case 150.

[0134] 11, the controller 130 determines whether it has received a high-level signal from the attachment sensor 154 and then a low-level signal from the attachment sensor 154 (S50). Then, in response to receiving a high-level signal from the attachment sensor 154 and then a low-level signal from the attachment sensor 154 (S50: Yes), the controller 130 stores the time in the EEPROM 134. Note that this time is essentially the time when the cartridge 200 was attached to the attachment case 150. Also, when the controller 130 receives a low-level signal from the attachment sensor 154, the cartridge 200 is attached to the attachment case 150. Also, when the controller 130 receives a high-level signal from the attachment sensor 154, the cartridge 200 is not attached to the attachment case 150.

[0135] Next, the controller 130 reads out CTG information such as identification information and ink amount Vc from the memory of the IC board 247 of the cartridge 200 attached to the attachment case 150 (S51). The controller 130 stores the read CTG information in the EEPROM 134.

[0136] The controller 130 then determines whether a command to execute a maintenance process has been input to the operation panel 22 (S52). If the controller 130 determines that a command to execute a maintenance process has not been input (S52: No), the controller 130 determines whether a waiting time Tk has elapsed since receiving a low-level signal from the attachment sensor 154 (S53). If the controller 130 determines that the waiting time Tk has not elapsed (S53: No), it executes S52. If the controller 130 determines that the waiting time Tk has elapsed (S53: Yes), it ends control including the maintenance process. Here, the waiting time Tk is preset as, for example, a time sufficient for the ink liquid level in the ink chamber 210 and the ink liquid level in the ink chamber 171 to reach the same height after the cartridge 200 is attached to the attachment case 150.

[0137] When the controller 130 determines that a command to perform maintenance processing has been input on the operation panel 22 (S52: Yes), it calculates the total amount Vt based on the ink amount Vc read from the memory of the IC board 247 and the ink amount Vs stored in the EEPROM 134 as the ink amount Vs in the liquid chamber 171 before the cartridge 200 was replaced (Vt = Vc + Vs: S54).

[0138] Next, the controller 130 determines whether the ink volume Vs in the liquid chamber 171 before the cartridge 200 was replaced is less than the tank threshold value Vth1 (S55). The tank threshold value Vth1 is, for example, a value equivalent to the ink volume stored in the liquid chamber 171 when all the ink stored in the cartridge 200 attached to the mounting case 150 has been consumed, or the maximum ink volume required for maintenance processing. This determines whether the ink level in the liquid chamber 171 will drop and reach directly above the outlet 174 after the maintenance processing is completed. In response to determining that the ink volume Vs in the liquid chamber 171 before the cartridge 200 was replaced was not less than the tank threshold value Vth1 (S55: No), the controller 130 starts the accepted maintenance processing (S61).

[0139] In response to determining that the ink volume Vs in the liquid chamber 171 before the cartridge 200 was replaced is less than the tank threshold value Vth1 (S55: Yes), the controller 130 determines whether the calculated total volume Vt is equal to or greater than the total volume threshold value Vth2 (S56). The total volume threshold value Vth2 is set to a value that, for example, prevents the flow rate Qc of ink flowing from the liquid chamber 210 of the cartridge 200 to the liquid chamber 171 of the tank 160 from becoming smaller than the flow rate Qp of ink flowing out of the liquid chamber 171 during maintenance processing. In response to determining that the calculated total volume Vt is equal to or greater than the total volume threshold value Vth2 (S56: Yes), the controller 130 starts the accepted maintenance processing (S61).

[0140] In response to determining that the calculated total amount Vt is less than the total amount threshold Vth2 (S56: No), the controller 130 determines the flow rate Qc from the ink amount Vc included in the CTG information (S57). The ink flow rate Qc from the liquid chamber 210 to the liquid chamber 171 after the cartridge 200 is mounted in the mounting case 150 varies depending on the difference between the liquid level in the liquid chamber 210 and the liquid level in the liquid chamber 171 from a reference position (e.g., a predetermined position P), i.e., the head difference.

[0141] For example, if the cartridge 200 is replaced after all the ink stored in the cartridge 200 has been consumed, the flow rate Qc will depend on the height of the liquid surface in the liquid chamber 210, i.e., the ink volume Vc, until the liquid surface in the liquid chamber 171 of the tank 160 reaches a predetermined position P. Therefore, if a function or table showing the relationship between the ink volume Vc and the flow rate Qc is stored in the EEPROM 134, the flow rate Qc can be determined based on the ink volume Vc read from the memory of the IC board 247.

[0142] Next, the controller 130 multiplies the determined flow rate Qc by the time ΔT1 from the time when a low-level signal was received from the attachment sensor 154 to the present to calculate the amount of ink Vs stored in the liquid chamber 171 (S58). Then, in response to determining that the determined flow rate Qc is equal to or greater than the threshold flow rate Qp (S59: Yes), the controller 130 determines whether the calculated ink amount Vs is equal to or greater than a threshold Vth3 (S60).

[0143] If the controller 130 determines that the calculated ink amount Vs is less than the threshold value Vth3 (S60: No), it repeats S58 to S60 at predetermined time intervals. The calculated ink amount Vs increases as the current time advances, and eventually becomes equal to or greater than the threshold value Vth3 (S60: Yes). Then, in response to determining that the ink amount Vs is equal to or greater than the threshold value Vth3 (S60: Yes), the controller 130 starts maintenance processing (S61).

[0144] After completing the maintenance process, the controller 130 calculates the ink amounts Vc and Vs after the maintenance process and stores them in the EEPROM 134 (S62). The controller 130 also stores the calculated ink amount Vc in the memory of the IC board 247 (S63), and ends control including the maintenance process.

[0145] In response to determining in S59 that the flow rate Qc is less than the flow rate Qp (S59: No), the controller 130 calculates a threshold value Vth4 (S64). The threshold value Vth4 is calculated as the difference between the flow rate Qp and the flow rate Qc multiplied by the time Tp for performing the maintenance process. If the flow rate Qc is less than the flow rate Qp, the ink in the liquid chamber 171 will decrease while the maintenance process is being performed. The difference between the flow rate Qp and the flow rate Qc corresponds to the amount of ink decreased from the liquid chamber 171 per unit time during the maintenance process. The value obtained by multiplying this difference by the time Tp corresponds to the total amount of ink decreased from the liquid chamber 171 during the maintenance process.

[0146] The controller 130 determines whether the calculated ink amount Vs is equal to or greater than the sum of thresholds Vth3 and Vth4 (an example of a second tank threshold) (S65). If the controller 130 determines that the calculated ink amount Vs is less than the sum of thresholds Vth3 and Vth4 (S65: No), it repeats S58 to S64 at predetermined time intervals. The calculated ink amount Vs increases as the current time advances, and eventually becomes equal to or greater than the sum of tank thresholds Vth1 and Vth4 (S65: Yes). Then, in response to determining that the ink amount Vs is equal to or greater than the sum of thresholds Vth3 and Vth4 (S65: Yes), the controller 130 starts maintenance processing (S61) and also executes S62 and S63.

[0147] [Effects of the third embodiment] According to the third embodiment, the time from when the cartridge 200 is attached to the attachment case 150, when the controller 130 accepts the maintenance process, until the maintenance process is actually executed can be shortened according to the calculated total volume Vt and flow rate Qc. Furthermore, the maintenance process can prevent air from entering the tube 32 or the head 21 from the liquid chamber 171.

[0148] [Modification of the third embodiment] In the above-described embodiment, the controller 130 determines the flow rate Qc based on the ink amount Vc read from the memory of the IC board 247 using a function or table indicating the relationship between the ink amount Vc and the flow rate Qc. However, this is not limited to this. For example, the printer 10 may further include a temperature sensor, and the controller 130 may select multiple functions or tables depending on the output of the temperature sensor. The multiple functions or tables are set so that the flow rate Qc decreases as the temperature detected by the temperature sensor decreases. As a result, if the ambient temperature of the printer 10 is low and the ink viscosity is high, the flow rate Qc determined decreases. Therefore, the maintenance process can prevent air from entering the tube 32 or the head 21 from the ink chamber 171.

[0149] [Other variations] In the first embodiment described above, the controller 130 is configured to detect whether the detection target portion 194 of the actuator 190 is located at the detection position based on a signal output by the liquid level sensor 155. However, the configuration of the liquid level sensor 155 is not particularly limited as long as it can detect the ink level in the liquid chamber 171. For example, the controller 130 may be a sensor that optically detects the ink level in the liquid chamber 171 using a prism that has a reflectance that varies depending on whether ink is in contact with the rear wall 164 of the liquid chamber 171. Alternatively, the liquid level sensor 155 may be an electrode rod inserted into the liquid chamber 171.

[0150] Furthermore, the controller 130 receiving a low-level signal from the mounting sensor 154, then receiving a high-level signal from the mounting sensor 154, and then receiving a low-level signal from the mounting sensor 154 is an example of the controller 130 determining that a cartridge has been mounted in the mounting case 150. Another example of the controller 130 determining that the cartridge 200 has been mounted in the mounting case 150 will be described below.

[0151] For example, the controller 130 receives a high-level signal from the cover sensor 88 and then a low-level signal. The controller 130 then reads the identification information from the memory of the IC board 247 and compares it with the identification information of the previous cartridge 200 stored in the EEPROM 134. The controller 130 may determine that the ink cartridge 30 has been replaced in the mounting case 150 in response to determining that the identification information read from the memory of the IC board 247 differs from the identification information stored in the EEPROM 134. In other words, "the controller 130 reads the identification information from the memory of the IC board 247 and compares it with the identification information of the previous cartridge 200 stored in the EEPROM 134. As a result, it is determined that the identification information read from the memory of the IC board 247 differs from the identification information stored in the EEPROM 134" is an example of the controller 130 determining that the cartridge 200 has been mounted in the mounting case 150. In this case, the controller 130 reads the identification information from the memory of the IC board 247, compares it with the identification information of the cartridge 200 before replacement stored in the EEPROM 134, and stores in the EEPROM the time at which it is determined that the identification information read from the memory of the IC board 247 differs from the identification information stored in the EEPROM 134. Alternatively, the time at which a low level signal is received after a high level signal is received from the cover sensor 88 may be stored in the EEPROM in S15.

[0152] Alternatively, for example, the controller 130 may receive a low-level signal after receiving a high-level signal from the cover sensor 88. The controller 130 then displays a confirmation screen on the display 17 to the user, indicating whether a new cartridge 200 has been installed in the mounting case 150. While the controller 130 is displaying the confirmation screen on the display 17, the controller 130 receives an input corresponding to the confirmation screen via the operation panel 22. If the received input corresponds to the installation of a new cartridge 200 in the mounting case 150, the controller 130 may determine that the ink cartridge 30 in the mounting case 150 has been replaced. That is, "the controller 130 receives a high-level signal from the cover sensor 88 and then a low-level signal. Then, the controller 130 causes the display 17 to display a confirmation screen that indicates to the user whether a new cartridge 200 has been installed in the mounting case 150. While the controller 130 is displaying the confirmation screen on the display 17, the controller 130 receives an input corresponding to the confirmation screen via the operation panel 22. The received input corresponds to the installation of a new cartridge 200 in the mounting case 150" is an example of the controller 130 determining that a cartridge 200 has been installed in the mounting case 150. In this case, the controller 130 stores in the EEPROM, as the time to be stored in S10, the time at which the input corresponding to the confirmation screen was received via the operation panel 22.

[0153] Furthermore, in the above-described embodiments, the ink moves from the liquid chamber 210 of the cartridge 200 to the liquid chamber 171 of the tank 160 due to a hydraulic head difference, but the movement of ink from the liquid chamber 210 to the liquid chamber 171 is not limited to being due to a hydraulic head difference. For example, the liquid chamber 171 of the tank 160 may be open to the atmosphere, while the liquid chamber 210 of the cartridge 200 may not be open to the atmosphere. In this case, by connecting the liquid chamber 210 and the liquid chamber 171 by a liquid flow path and a gas flow path, gas-liquid exchange occurs between the liquid chamber 171 and the liquid chamber 210 due to gravity or the like, and ink moves from the liquid chamber 210 to the liquid chamber 171.

[0154] Furthermore, in each of the above-described embodiments, ink is described as an example of a liquid, but the liquid may be, for example, a pretreatment liquid that is ejected onto paper or the like prior to ink during image recording, or water for cleaning the head 21. [Explanation of symbols]

[0155] 10. Printer (liquid discharge device) 17···Display (alarm) 21...head 130 Controller 132···ROM (memory) 133 RAM (memory) 134···EEPROM (memory) 150···Attached Case 155 Liquid level sensor 160... Tank 171...Liquid chamber (2nd liquid chamber) 181 Needle (flow path) 200 cartridges 210...Liquid chamber (1st liquid chamber) 213 Ink valve chamber (flow path)

Claims

1. a mounting case into which a cartridge having a first liquid chamber in which liquid is stored is mounted; a tank having a second liquid chamber connected to the cartridge attached to the attachment case; a flow path, one of which communicates with the second liquid chamber and the other of which communicates with the first liquid chamber of the cartridge connected to the tank; a head connected to the flow path; The interface and A liquid ejection device comprising: The above controller is determining whether the cartridge is attached to the attachment case; The amount of liquid Vs stored in the second liquid chamber is calculated. after the cartridge is mounted in the mounting case, before a predetermined waiting time has elapsed as the time required for the liquid level of the liquid stored in the second liquid chamber to reach a predetermined height, a maintenance process is accepted to discharge the liquid stored in the second liquid chamber from the head; In response to determining that the cartridge is attached to the attachment case, a liquid volume Vc of the liquid stored in the first liquid chamber is read from a cartridge memory of the cartridge through the interface; A liquid discharge device that executes the accepted maintenance process on the condition that the liquid volume Vs before the cartridge is attached to the attachment case is less than the first tank threshold value, and the total volume Vt, which is the sum of the liquid volume Vs and the read liquid volume Vc, is greater than or equal to the total volume threshold value.

2. A mounting case in which a cartridge having a first liquid chamber in which a liquid is stored is mounted; a tank having a second liquid chamber connected to the cartridge attached to the attachment case; a flow path, one of which communicates with the second liquid chamber and the other of which communicates with the first liquid chamber of the cartridge connected to the tank; a head connected to the flow path; The interface and A liquid ejection device comprising: The above controller is determining whether the cartridge is attached to the attachment case; The amount of liquid Vs stored in the second liquid chamber is calculated. A maintenance process is received to discharge the liquid stored in the second liquid chamber from the head, In response to determining that the cartridge is attached to the attachment case, a liquid volume Vc of the liquid stored in the first liquid chamber is read from a cartridge memory of the cartridge through the interface; executes the received maintenance process under the condition that the liquid volume Vs before the cartridge is attached to the attachment case is less than a first tank threshold value, and the total volume Vt, which is the sum of the liquid volume Vs and the read liquid volume Vc, is equal to or greater than a total volume threshold value; The above controller is determining a flow rate Qc of the liquid flowing from the first liquid chamber to the second liquid chamber based on the read liquid volume Vc; calculating an updated liquid volume Vs by multiplying the flow rate Qc by the time elapsed since it was determined that the cartridge was attached to the attachment case, and adding this to the liquid volume Vs before the cartridge was attached to the attachment case; The liquid discharging device executes the maintenance process when the total amount Vt is less than the total amount threshold and the renewal liquid amount Vs is equal to or greater than the first tank threshold.

3. The above controller is On the condition that the flow rate Qc is less than a flow rate threshold, a liquid volume Vth is calculated by multiplying the difference between the flow rate threshold and the flow rate Qc by the time for which the maintenance process is performed, and the result is added to the first tank threshold to calculate a second tank threshold; The liquid discharging device according to claim 2 , wherein the maintenance process is executed when the renewal liquid volume Vs is equal to or greater than the second tank threshold value.

4. Further comprising a temperature sensor, 4. The liquid discharging device according to claim 2, wherein the controller determines the flow rate Qc to be smaller as the temperature according to the signal received from the temperature sensor becomes lower.

5. A pump and a cap connected to the pump, 5. The liquid discharging device according to claim 1, wherein, when performing the maintenance process, the controller drives the pump while the cap is covering the nozzles of the head, thereby discharging liquid from the nozzles of the head.

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