Liquid discharge device

Aspects of a disclosure relates to a liquid discharge device enables previously disabled liquid discharge through a head after a cartridge including a first liquid chamber is replaced and before the liquid level in a second liquid chamber of a tank reaches a predetermined level or higher. Another aspects of the disclosure relates to a liquid discharge device that deactivates an alarm after a cartridge including a first liquid chamber is replaced and before the liquid level in a second liquid reaches a predetermined level or higher.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Japanese Patent Application No. 2018-185809 filed on Sep. 28, 2018, the content of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a liquid discharge device for discharging liquid.

BACKGROUND

A known inkjet printer includes a removable main tank, a subtank storing ink fed from the main tank that has been installed, and an image recording unit that discharges ink from the subtank to print an image (e.g., JP-A-2008-213162). In the above inkjet printer, the main tank and the subtank each have the internal space open to the air. When the main tank is installed in the inkjet printer, the liquid height difference between the internal spaces of the main tank and the subtank (hereinafter, the water head difference) causes ink transfer between the tanks toward the same liquid level under the pressure of water head. The inkjet printer then displays, on a display, a message urging replacement of the cartridge when the residual amount of the ink detected by a residual amount sensor decreases below a threshold, or a message indicating that the ink cartridge is empty. The inkjet printer then disables the ink discharge through the image recording unit when the ink cartridge becomes empty.

SUMMARY

After the main tank is replaced, ink flows from the main tank into the subtank. A residual amount sensor may be provided to detect the ink in the subtank. As the ink flows from the main tank into the subtank, a detection signal from the residual amount sensor changes. In response to a change in the detection signal from the residual amount sensor, the inkjet printer may enable the disabled ink discharge through the image recording unit. However, the ink discharge can remain disabled for a relatively long time until the signal output from the residual amount sensor changes after the ink starts flowing from the main tank into the subtank. The user may thus have an impression that image recording cannot be started readily after the main tank is replaced.

Also, when the detection signal from the residual amount sensor changes, the inkjet printer can delete the message for cartridge replacement or the massage indicating the empty cartridge from the display. However, the message on the display remains for a relatively long time until the signal output from the residual amount sensor changes after the ink starts flowing from the main tank into the subtank. The user seeing the message on the display after replacing the main tank may misunderstand that the main tank replacement has failed. This may also cause an inconvenience to the user to wait for image recording.

One aspects of the present disclosure is directed to a liquid discharge device that enables previously disabled liquid discharge through a head after a cartridge including a first liquid chamber is replaced and before the liquid level in a second liquid chamber reaches a predetermined level or higher.

Another aspects of the present disclosure is directed to a liquid discharge device that deactivates an alarm after a cartridge including a first liquid chamber is replaced and before the liquid level in a second liquid reaches a predetermined level or higher.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described below. The embodiments described below are merely examples and can be appropriately modified without departing from the spirit and scope of the present disclosure. An up-down direction7is defined based on the posture of a multifunction peripheral10placed on a horizontal plane with ink cartridges50installed for use (posture inFIG. 1, hereinafter referred to as a use posture), a front-back direction8is defined using a surface of the multifunction peripheral10with an opening13as a front surface, and a left-right direction9is defined for the multifunction peripheral10viewed from the front surface. In the present embodiment, the up-down direction7in the use posture corresponds to a vertical direction, and the front-back direction8and the left-right direction9correspond to a horizontal direction.

First Embodiment

The multifunction peripheral10and an ink feeder15according to a first embodiment will now be described.

Overall Structure of Multifunction Peripheral10

As shown inFIGS. 1A and 1B, the multifunction peripheral10(an example of a liquid discharge device) is in the shape of a substantially rectangular parallelepiped. The multifunction peripheral10includes a printer unit11, a scanner unit12, and an operation panel22. The printer unit11, which is a lower part of the multifunction peripheral10, records an image on a sheet of paper (sheet28) with an inkjet recording method (seeFIG. 2). The scanner unit12with a scanning function is located above the printer unit11. The printer unit11includes a housing14having a front opening13, and the ink feeder15on the right of the opening13in the housing14.

The operation panel22is located in front of the scanner unit12. The operation panel22is operated by a user to cause the multifunction peripheral10to perform image recording by the printer unit11or image reading by the scanner unit12. The operation panel22includes a display17. The display17may be, for example, a liquid crystal display or an organic electroluminescence (EL) display, and has a display screen on which various items of information appear. The display17is an example of an alarm. However, the alarm is not limited to the display17, and may be a speaker, a light-emitting diode (LED) lamp, or a combination of these devices. The operation panel22outputs an operation signal corresponding to a user's operation to a controller230. For example, the operation panel22may include a push button, or may include a touch sensor overlaid on the display.

As shown inFIG. 2, the housing14contains a feeder16, a feed tray20, a discharge tray21, a conveyance roller pair45, a recorder24, a discharge roller pair46, and a platen42.

As shown inFIGS. 1A and 1B, the feed tray20is insertable into and removable from the housing14in the front-back direction8through the opening13. The opening13is located in the front surface of the multifunction peripheral10in the middle in the left-right direction9. As shown inFIG. 2, the feed tray20can support a plurality of sheets28stacked on one another. The discharge tray21is located above the feed tray20, and is inserted or removed in the front-back direction8together with the feed tray20. The discharge tray21supports sheets28discharged from the discharge roller pair46.

The feeder16feeds a sheet28supported on the feed tray20to a conveyance path38. As shown inFIG. 2, the feeder16includes a feed roller25, a feed arm26, and a shaft27. The feed roller25is rotatably supported at an end of the feed arm26. The feed roller25is driven by a feed motor (not shown). The feed arm26is rotatably supported by the shaft27that is supported by a frame of the printer unit11. The feed arm26is rotationally urged toward the feed tray20by its weight or by an elastic force from a spring or another member.

Hereafter, the rotation of the feed roller25, a conveyance roller34, and a discharge roller36for conveyance of the sheet28in a conveyance direction38A of the sheet28will be referred to as normal rotation.

As shown inFIG. 2, the conveyance path38is a space partially defined by an outer guide18and an inner guide19facing each other at a predetermined distance in the printer unit11. The conveyance path38extends rearward from the rear end of the feed tray20. The conveyance path38extends upward at the rear of the printer unit11, U-turns, and extends forward through a space between the recorder24and the platen42into the discharge tray21. As shown inFIGS. 2 and 3, a part of the conveyance path38between the conveyance roller pair45and the discharge roller pair46is located substantially in the middle of the multifunction peripheral10in the left-right direction9, and extends in the front-back direction8. The conveyance direction38A of the sheet28on the conveyance path38is indicated by an arrow inFIG. 2.

As shown inFIG. 2, the conveyance roller pair45is located upstream from the recorder24in the conveyance direction38A. The conveyance roller pair45includes the conveyance roller34and a pinch roller35facing each other. The conveyance roller34is driven by a conveyance motor (not shown) to rotate in normal or reverse direction. The pinch roller35rotates in accordance with the rotation of the conveyance roller34. The sheet28is conveyed in the conveyance direction38A between the conveyance roller34and the pinch roller35that are rotating in normal direction.

As shown inFIG. 2, the discharge roller pair46is located downstream from the recorder24in the conveyance direction38A. The discharge roller pair46includes the discharge roller36and a spur37facing each other. The discharge roller36is driven by the conveyance motor (not shown) to rotate in normal or reverse direction. The spur37rotates in accordance with the rotation of the discharge roller36. The sheet28is conveyed in the conveyance direction38A between the discharge roller36and the spur37that are rotating in normal direction.

As shown inFIG. 2, the recorder24is located between the conveyance roller pair45and the discharge roller pair46in the conveyance direction38A. The recorder24faces the platen42in the up-down direction7across the conveyance path38. The recorder24includes a carriage23and a recording head39included in the carriage23.

As shown inFIG. 3, the carriage23is supported by guide rails43and44spaced from each other in the front-back direction8and each extending in the left-right direction9. The guide rails43and44are supported by a frame (not shown). The carriage23is connected to a known belt mechanism included in the guide rail44. The belt mechanism is driven by a carriage drive motor (not shown) to rotate. As the belt mechanism rotates, the carriage23is guided by the guide rails43and44to reciprocate in the left-right direction9. The carriage23moves beyond the right and left ends of a width38B of the conveyance path38, as indicated by dash-dot lines inFIG. 3.

The recording head39and four subtanks100included in the ink feeder15are connected to each other with four ink tubes32. The recording head39is connected to a control board (not shown) with a flexible flat cable33.

The four subtanks100include a magenta subtank100M, a cyan subtank100C, a yellow subtank100Y, and a black subtank100B. The magenta subtank100M, the cyan subtank100C, the yellow subtank100Y, and the black subtank100B are herein collectively referred to as the subtanks100, unless they are distinguished.

The four ink tubes32include a yellow ink tube32Y, a cyan ink tube32C, a magenta ink tube32M, and a black ink tube32B. The yellow ink tube32Y, the cyan ink tube32C, the magenta ink tube32M, and the black ink tube32B are herein collectively referred to as the ink tubes32, unless they are distinguished. The four ink tubes32are bundled together.

The flexible flat cable33electrically connects the control board including a control unit to the recording head39. The flexible flat cable33transfers a control signal output from the control unit to the recording head39.

As shown inFIG. 2, the recording head39includes a plurality of nozzles40on its bottom surface. The nozzles40have ends exposed at the bottom surface of the recording head39. The recording head39discharges ink through the nozzles40as fine droplets. While the carriage23is moving, the recording head39discharges ink droplets toward the sheet28supported on the platen42. This records an image on the sheet28. In this process, the ink stored in the four subtanks100is used.

As shown inFIGS. 2 and 3, the platen42is located between the conveyance roller pair45and the discharge roller pair46on the conveyance path38. The platen42faces the recorder24in the up-down direction7across the conveyance path38. The platen42supports the sheet28from below when the conveyance roller pair45conveys the sheet28.

As shown inFIG. 1B, the housing14has a front right opening47. The housing14contains the ink feeder15with a front surface exposed at the opening47. The housing14has a cover48attached to open and close the opening47. The cover48has a lower end under the opening47, which is pivotably supported by the housing14about an axis in the left-right direction9. The cover48is pivotable between a closed position (shown inFIG. 1A) at which the opening47is closed and an open position (shown inFIG. 1B) at which the opening47is open.

As shown inFIG. 1A, the cover48has a translucent part49. The translucent part49is translucent to allow the interior to be viewable from outside the cover48. With the cover48at the closed position, the translucent part49allows viewing of the front surfaces of the ink cartridges50installed in the ink feeder15.

The multifunction peripheral10includes a cover sensor88(seeFIG. 13). The cover sensor88may be, for example, a mechanical sensor such as a switch with and from which the cover48contacts and separates, or an optical sensor for which light is blocked or transmitted depending on the position of the cover48. The cover sensor88outputs a signal corresponding to the position of the cover48to the controller230. More specifically, the cover sensor88outputs a low-level signal to the controller230when the cover48is at the closed position. The cover sensor88outputs a high-level signal having a higher signal intensity than the low-level signal to the controller230when the cover48is at a position different from the closed position. In other words, the cover sensor88outputs a high-level signal to the controller230when the cover48is at the open position.

As shown inFIG. 4, the ink feeder15includes the four ink cartridges50, an installation case71, the four subtanks100, and an air communication portion70(seeFIGS. 5 and 11).

As shown inFIGS. 1A, 1B, and 3, the four ink cartridges50(examples of cartridges) include a magenta ink cartridge50M, a cyan ink cartridge50C, a yellow ink cartridge50Y, and a black ink cartridge50B. The magenta ink cartridge50M, the cyan ink cartridge50C, the yellow ink cartridge50Y, and the black ink cartridge50B are herein collectively referred to as the ink cartridges50, unless they are distinguished.

InFIG. 4, the magenta ink cartridge50M, which is the leftmost one of the four ink cartridges50in the left-right direction9, alone is installed in the installation case71.

As shown inFIGS. 5 and 6, an ink cartridge50includes a cartridge body51and a joint receiver52. The cartridge body51includes a first reservoir53(an example of a first liquid chamber) storing ink (an example of liquid).

The cartridge body51is in the shape of a substantially rectangular parallelepiped box. The cartridge body51is substantially rectangular as viewed in the up-down direction7and the front-back direction8. The cartridge body51has a downward protrusion65on its front end. The cartridge body51has an upper wall54, a lower subwall55, a right wall56(seeFIG. 4), a left wall57(seeFIG. 4), a rear wall58, a front wall59, and a lower wall60. The lower wall60is located at the front part and the lower end of the cartridge body51, and below the lower subwall55. The lower subwall55is located behind the lower wall60. The cartridge body51has a communication port61that is open rearward (an example of a horizontal direction) in the protrusion65. The communication port61is an opening defined by the lower subwall55, the lower wall60, the right wall56, and the left wall57.

The upper wall54has a contact part64protruding upward in the middle in the front-back direction8. The contact part64comes into contact with a lock lever79(described later) on the installation case71.

The contact part64receives an integrated circuit (IC) chip66(an example of a cartridge memory) on its upper surface. The IC chip66includes an IC chip. The IC chip66also includes a memory (not shown). In the IC chip66, the IC chip is electrically connected to the memory. The IC chip66is exposed on its upper surface for electrical connection with a contact152. More specifically, the IC chip66is electrically connected to the contact152when the ink cartridge50is installed in the installation case71. The controller230can read information from the memory of the IC chip66through the contact152and the IC chip66, and can write information to the memory of the IC chip66through the contact152and the IC chip66.

The memory of the IC chip66stores an ink amount Vc and identification information for identifying each ink cartridge50. For a fresh ink cartridge50, the memory of the IC chip66stores an initial ink amount Vc0as the ink amount Vc. The initial ink amount Vc0is an example of a maximum liquid amount indicating a maximum amount of ink that can be stored in the ink cartridge50. In other words, the initial ink amount Vc0indicates the amount of ink stored in a fresh ink cartridge50. Hereafter, information stored in the memory of the IC chip66may be collectively referred to as cartridge (CTG) information. A fresh ink cartridge herein refers to an unused ink cartridge50from which ink has yet to flow out after manufactured and sold.

The memory of the IC chip66includes, for example, a non-writable storage area in which no information is overwritten by the controller230and a writable storage area in which information can be overwritten by the controller230. For example, identification information is stored in the non-writable area, and the ink amount Vc is stored in the writable area.

The upper surface of the lower subwall55, which defines the bottom surface of the first reservoir53, is inclined downward to the protrusion65in the front-back direction8.

The joint receiver52is cylindrical and extends rearward from a part of the cartridge body51surrounding the communication port61. The joint receiver52receives a joint102(described later) included in a subtank100.

FIG. 5shows the ink cartridge50installed in the subtank100.FIG. 6shows the ink cartridge50separate from the subtank100. The installed state will be detailed later.

The joint receiver52includes a plug62that can close the communication port61and a spring63that urges the plug62rearward. As shown inFIG. 6, under no external force applied to the ink cartridge50, the plug62is located to close the communication port61. The spring63extends in the front-back direction8between the plug62and the front wall59, and can be compressed in the front-back direction8. As shown inFIG. 5, when receiving a forward external force greater than the elastic force of the spring63from the joint102, the plug62moves forward to leave the communication port61.

The installation case71is in the shape of a substantially rectangular parallelepiped box that is open forward. The installation case71has an upper wall72, a lower wall73, a right wall74, a left wall75, a rear wall76, and three partition walls77. The upper wall72, the lower wall73, the right wall74, the left wall75, and the rear wall76define an internal space78opening forward. The three partition walls77are parallel with the right wall74and the left wall75, and partition the internal space78into four spaces. Each of the four partition spaces receives the corresponding one of the four ink cartridges50.

As shown inFIGS. 4, 5, and 6, the installation case71includes lock levers79that hold the ink cartridges50inside the internal space78. The lock levers79are plate-like members extending in the front-back direction. Each lock lever79is pivotably attached, at the center, to the upper wall72about an axis in the left-right direction9. The lock lever79pivots between a locked position inclined rearward and an unlocked position inclined forward. Under no external force applied, the lock lever79is inclined rearward to the locked position with its weight. The lock lever79at the locked position has the rear end in contact with the front surface of the contact part64of the ink cartridge50inside the internal space78to prevent the ink cartridge50from moving forward in the front-back direction8. When the front end of the lock lever79at the locked position is depressed with, for example, a finger of the user, the lock lever79pivots from the locked position to the unlocked position. The lock lever79at the unlocked position has the rear end located above the front surface of the contact part64. The lock lever79at the unlocked position is not in contact with the contact part64of the ink cartridge50moving forward in the front-back direction8, thus allowing the ink cartridge50to be removable from the installation case71.

The contact152(an example of an interface) is located on the upper wall72of the installation case71. The contact152protrudes downward toward the internal space78of the installation case71from the upper wall72. The contact152is located to be in contact with the IC chip66(described below) of the ink cartridge50when the ink cartridge50is installed in the installation case71. The contact152is conductive and elastically deformable in the up-down direction7. The contact152is electrically connected to the controller230.

The installation sensor154is located on the upper wall72of the installation case71. The installation sensor154detects the ink cartridge50installed in the installation case71. The installation sensor154includes a light emitter and a light receiver located at a distance from each other in the left-right direction9. When the ink cartridge50is installed in the installation case71, a detectable unit (not shown) of the ink cartridge50is located between the light emitter and the light receiver of the installation sensor154. In other words, the light emitter and the light receiver of the installation sensor154are located opposite to each other across the detectable unit of the ink cartridge50installed in the installation case71.

The installation sensor154outputs different signals (installation signals in the drawings) depending on whether light emitted from the light emitter in the left-right direction9is received by the light receiver. The installation sensor154outputs a low-level signal to the controller230when, for example, the intensity of the light received by the light receiver is lower than a threshold intensity. In contrast, the installation sensor154outputs a high-level signal having a higher signal intensity than the low-level signal to the controller230when the intensity of the light received by the light receiver is equal to or higher than the threshold intensity. The high-level signal is an example of a third signal, and the low-level signal is an example of a fourth signal.

FIGS. 4 to 11show the subtanks100(examples of tanks). The subtanks100are located under the lower wall73of the installation case71.

As shown inFIG. 7, each subtank100includes a tank body101and the joint102. The tank body101includes an internal second reservoir105(an example of a second liquid chamber) to store ink. The subtank100includes a liquid flow path103and a gas flow path104that communicate with the second reservoir105. The liquid flow path103and the gas flow path104are defined inside the tank body101and the joint102. The subtank100also includes an air communication port106(seeFIGS. 9, 10, and 12A) that allows the second reservoir105to communicate with the outside.

Liquid Flow Path103and Gas Flow Path104

As shown inFIG. 7, the liquid flow path103and the gas flow path104are located in parallel.

The liquid flow path103has a first opening131, a second opening132, a vertical part133, and a horizontal part134. The first opening131is formed in one end (rear end) of the liquid flow path103and communicates with the second reservoir105. The first opening131is open in the up-down direction7. The second opening132is formed in the opposite end (front end) of the liquid flow path103and is open to the outside. The second opening132is open in the front-back direction8. With the ink cartridge50installed, the second opening132is located in the first reservoir53of the ink cartridge50. The vertical part133is a part of the liquid flow path103extending upward from the first opening131. The horizontal part134is a part of the liquid flow path103extending rearward from the second opening132. The upper end of the vertical part133is connected to the rear end of the horizontal part134.

The gas flow path104has a third opening141, a fourth opening142, a vertical part143, and a horizontal part144. The third opening141is formed in one end (rear end) of the gas flow path104and communicates with the second reservoir105. The third opening141is open in the up-down direction7. The fourth opening142is formed in the opposite end (front end) of the gas flow path104and is open to the outside. The fourth opening142is open in the front-back direction8. With the ink cartridge50installed, the fourth opening142communicates with the first reservoir53of the ink cartridge50. The vertical part143is a part of the gas flow path104extending upward from the third opening141. The horizontal part144is a part of the gas flow path104extending rearward from the fourth opening142. The upper end of the vertical part143is connected to the rear end of the horizontal part144.

The tank body101has outer walls defining the shape of a substantial rectangular parallelepiped. The tank body101is substantially T-shaped as viewed in the up-down direction7(seeFIGS. 9 and 10), substantially rectangular as viewed in the front-back direction8(seeFIG. 8), and L-shaped as viewed in the left-right direction9(seeFIGS. 4 to 7).

As shown inFIGS. 4 to 11, the outer walls of the tank body101include a rear upper wall107, a curved upper wall130, a front upper wall108, a lower wall109, two rear side walls110, two front curved side walls111, a rear wall112, and a front wall113. The rear upper wall107extends forward from the rear end and is inclined upward with respect to the horizontal plane. The curved upper wall130extends from the front end of the rear upper wall107and curves upward as it extends forward. The front upper wall108extends from the upper end of the curved upper wall130forward in parallel with the horizontal plane. The lower wall109extends in the front-back direction8in parallel with the horizontal plane. The lower wall109is T-shaped as viewed in the up-down direction7. The rear side walls110connect the rear upper wall107and the lower wall109in the up-down direction7. The rear side walls110are substantially rectangular as viewed in the left-right direction9. As shown inFIG. 9, adjacent tank bodies101for different inks share one rear side wall110. The front curved side walls111connect the curved upper wall130and the front upper wall108to the lower wall109in the up-down direction7. The front curved side walls111are substantially rectangular as viewed in the left-right direction9, and L-shaped with a round corner as viewed in the up-down direction7. The rear wall112extends upward from the rear end of the lower wall109, and is connected to the two right and left rear side walls110and the rear upper wall107. The front wall113extends upward from the front end of the lower wall109, and is connected to the two right and left front curved side walls111.

As shown inFIGS. 7 and 11, the lower wall109has a communication port129that communicates with the second reservoir105. The communication port129is connected to one end of the ink tube32, and the ink tube32connects the second reservoir105and the recording head39.

The tank body101includes an inner cylinder114extending in the front-back direction8at the front end and the upper part of the tank body101. The inside of the inner cylinder114communicates with the opening defined by the front wall113, the two right and left front curved side walls111, and the front upper wall108. The rear end of the joint102is attachable to the inner cylinder114. In the installed state with the joint102attached to the inner cylinder114, the inside of the inner cylinder114communicates with the inside of the joint102.

As shown inFIG. 10, the tank body101has a wide part150and a narrow part151aligned with each other in the front-back direction8. The wide part150is a rear part in the tank body101in the front-back direction8and includes the two rear side walls110and the rear wall112. The narrow part151is located at the front end in the front-back direction8(an example of an end in a first direction) in the tank body101and includes the two front curved side walls111and the front wall113. The narrow part151has a width in the left-right direction9(an example of a second direction orthogonal to the first direction) smaller than the width of the wide part150in the left-right direction9. The second reservoir105extends across the wide part150and the narrow part151.

As shown inFIG. 8, the width of the wide part150in the left-right direction9is substantially the same as the width of the ink cartridge50in the left-right direction9. Thus, the width of the narrow part151in the left-right direction9is smaller than the width of the ink cartridge50in the left-right direction9.

As shown inFIGS. 7 and 11, the tank body101includes a vertical wall115and a horizontal wall116in the upper front part of the tank body101.

The vertical wall115extends in the up-down direction7and is located between the front wall113and the curved upper wall130in the front-back direction8. The vertical wall115connects the two right and left front curved side walls111, and partitions the space defined by the front wall113, the front upper wall108, and the two front curved side walls111into front and rear parts. The lower end position of the vertical wall115is a position at the first opening131of the liquid flow path103in the up-down direction7, and also a position at the third opening141of the gas flow path104in the up-down direction7. The lower end position of the vertical wall115is equal to the lower end position of the front end of the rear upper wall107. More specifically, the upper surface of the second reservoir105is defined by an imaginary plane on the lower end position of the vertical wall115and parallel with the horizontal plane, and the bottom surface of the rear upper wall107.

The horizontal wall116extends forward from the upper end of the vertical wall115. The horizontal wall116extends into the inner cylinder114. The horizontal wall116connects the two right and left front curved side walls111, and also connects the facing inner surfaces inside the inner cylinder114in the left-right direction9. The horizontal wall116partitions the space defined by the front upper wall108and the two front curved side walls111into upper and lower parts, and also partitions the space defined by the inner cylinder114into upper and lower parts.

As shown inFIG. 10, the vertical part133of the liquid flow path103is defined by the vertical wall115, the front wall113, and the two front curved side walls111. The vertical part133of the liquid flow path103has a rectangular cross section orthogonal to the up-down direction7. The vertical part133of the liquid flow path103is flush with the two front curved side walls111defining the second reservoir105. Thus, the vertical part133of the liquid flow path103has a width in the left-right direction9equal to the width of the second reservoir105defined by the narrow part151in the left-right direction9.

As shown inFIG. 10, the vertical part143of the gas flow path104is defined by the curved upper wall130, the vertical wall115, and the two front curved side walls111. The vertical part143of the gas flow path104has a rectangular cross section orthogonal to the up-down direction7. The vertical part143of the gas flow path104is flush with the two front curved side walls111defining the second reservoir105. Thus, the vertical part143of the gas flow path104has a width in the left-right direction9equal to the width of the second reservoir105defined by the narrow part151in the left-right direction9.

As shown inFIG. 10, the third opening141of the gas flow path104has a length149in the front-back direction8(an example of the horizontal direction), and the first opening131of the liquid flow path103has a length148in the front-back direction8(an example of the horizontal direction). The length149is greater than the length148. The third opening141of the gas flow path104has a length in the left-right direction9equal to the length of the first opening131of the liquid flow path103in the left-right direction9. Thus, the third opening141of the gas flow path104has a larger opening area than the first opening131of the liquid flow path103.

As shown inFIG. 7, the opening area of the gas flow path104in the vertical part143of the gas flow path104increases toward the third opening141of the gas flow path104. In the vertical part133of the liquid flow path103, the opening area of the liquid flow path103remains constant in the up-down direction7.

As shown inFIG. 7, the horizontal part134of the liquid flow path103in the tank body101is defined by the front upper wall108, the horizontal wall116, the two front curved side walls111, and the inner cylinder114. The horizontal part144of the gas flow path104in the tank body101is defined by the horizontal wall116, the two front curved side walls111, and the inner cylinder114.

First Rib117

As shown inFIGS. 7 and 11, the tank body101includes a first rib117connected to the vertical wall115. The first rib117protrudes from a front curved side wall111and extends downward from the vertical wall115. The first rib117is separate from the lower wall109. Each of the two right and left front curved side walls111has the first rib117. The single second reservoir105includes the two first ribs117separate from each other in the left-right direction9.

Liquid Level Sensor155

As shown inFIG. 7, a liquid level sensor155detects the liquid level of the second reservoir105of the tank body101equal to or higher than a predetermined level B. The predetermined level B is lower than an imaginary line L extending through the third opening141of the gas flow path104in the horizontal direction. The liquid level sensor155optically detects the liquid level of the ink in the second reservoir105at the predetermined level B using a prism with different reflectance values depending on whether the ink is in contact with the rear wall112of the tank body101at the predetermined level B.

The liquid level sensor155includes a light emitter and a light receiver located at a distance from each other in the left-right direction9. The liquid level sensor155outputs different signals (liquid level signals in the drawings) depending on whether light output from the light emitter is received by the light receiver. In the present embodiment, when the second reservoir105of the tank body101has a liquid level equal to or higher than the predetermined level B, the liquid level sensor155outputs a low-level signal. When the second reservoir105of the tank body101has a liquid level lower than the predetermined level B, the liquid level sensor155outputs a high-level signal. The low-level signal is an example of a first signal. The high-level signal is an example of a second signal.

As shown inFIGS. 4 to 9 and 11, the joint102includes a joint body118, an inner wall119, a plug120(seeFIGS. 6 and 7), and a spring121(seeFIGS. 6 and 7).

As shown inFIG. 7, the joint body118includes an external cylinder122at its rear end, a front end123, and a main body124connecting the external cylinder122and the front end123. The external cylinder122is cylindrical and extends in the front-back direction8. The external cylinder122is fitted in the inner cylinder114of the tank body101. This fixes the joint body118to the tank body101. The front end123is disc-shaped with the center at an axis in the front-back direction8. The main body124is cylindrical and extends in the front-back direction8. The main body124has an upper opening125facing upward and a lower opening126facing downward at the front end of the main body124.

As shown inFIGS. 7 and 8, the inner wall119is located inside the joint body118. The inner wall119extends rearward from the front end123beyond the external cylinder122. The inner wall119has a partition wall127and a second rib128. As shown inFIG. 8, the inner wall119is T-shaped as viewed in the front-back direction8. The partition wall127has a rear end surface in contact with the front end surface of the horizontal wall116in the tank body101. The partition wall127and the horizontal wall116partition the internal space of the connection part between the joint body118and the tank body101into the liquid flow path103and the gas flow path104.

The partition wall127extends across the inside of the joint body118in the left-right direction9. The partition wall127extends rearward from the front end123. The joint body118has an internal space partitioned by the partition wall127into upper and lower parts.

The second rib128protrudes downward from the middle of the partition wall127in the left-right direction9. The second rib128extends rearward from the front end123. The second rib128and the joint body118have a gap between them.

The horizontal part134of the liquid flow path103in the joint102is defined by the inner surface of the joint body118and the bottom surface of the inner wall119. The horizontal part134of the liquid flow path103in the joint102has a substantially semicircular cross section. More specifically, the cross section of the horizontal part134has a semicircular shape with an upper part divided by the second rib128into right and left areas, and a continuous lower part that is not divided into right and left areas. The horizontal part144of the gas flow path104in the joint102is defined by the inner surface of the joint body118and the upper surface of the inner wall119. The horizontal part144of the gas flow path104in the joint102has a semicircular cross section.

The plug120is a cylindrical member and located outside the main body124of the joint body118. The plug120is movable in the front-back direction8along the main body124. The spring121has a front end fixed to the rear end of the plug120, and a rear end in contact with a buffer tank90in the air communication portion70and the external cylinder122of the joint body118. The spring121urges the plug120forward. Under no external force applied, the plug120is located at the front end of the joint body118and closes the upper opening125and the lower opening126. Under a rearward external force greater than the elastic force of the spring121applied, the plug120moves rearward to open the upper opening125and the lower opening126. When the ink cartridge50is installed, the joint receiver52of the ink cartridge50comes into contact with the plug120. Under the external force applied during the installation of the ink cartridge50, the plug120in contact with the joint receiver52moves rearward.

Installed State of Ink Cartridge50

In the installed state of the ink cartridge50installed in the subtank100as shown inFIGS. 5 and 7, the joint body118of the subtank100is inserted in the joint receiver52of the ink cartridge50in the front-back direction8and further in the communication port61. In this installed state, the second opening132of the liquid flow path103and the fourth opening142of the gas flow path104in the subtank100enter the first reservoir53of the ink cartridge50. As shown inFIGS. 4 and 5, the ink cartridge50can be removed from and installed in the subtank100in the front-back direction8.

Layout of Ink Cartridge50and Subtank100

The layout of the ink cartridge50and the subtank100will now be described. In the layout described below, the ink cartridge50is installed in the installation case71, and the ink cartridge50and the subtank100are in the use posture shown inFIG. 5.

As shown inFIG. 5, the protrusion65of the ink cartridge50is located at substantially the same position as the joint102in the up-down direction7, whereas the part of the ink cartridge50above the protrusion65is located higher than the joint102. Thus, a most part of the first reservoir53of the ink cartridge50is located higher than the second opening132. The upper part of the subtank100, or the part at and above the curved upper wall130, is located at substantially the same position as the joint102, whereas the part of the subtank100below the curved upper wall130is located lower than the joint102. Thus, a most part of the second reservoir105of the subtank100is located lower than the third opening141.

The part of the first reservoir53above the protrusion65is located higher than the horizontal part134of the liquid flow path103and the horizontal part144of the gas flow path104. The second reservoir105is located lower than the horizontal part134of the liquid flow path103and the horizontal part144of the gas flow path104. The lower part of the first reservoir53and the upper part of the second reservoir105are arranged coaxially in the front-back direction8. The first reservoir53has a larger volume than the second reservoir105.

The horizontal part144of the gas flow path104is located higher than the horizontal part134of the liquid flow path103.

As shown inFIG. 7, the first opening131of the liquid flow path103, the third opening141of the gas flow path104, and the air communication port106are located rearward in the stated order from the communication port61of the first reservoir53. The position of the communication port61of the first reservoir53in the up-down direction7corresponds to the position in the up-down direction7at which the first reservoir53and the liquid flow path103communicate with each other. The rearward direction from the communication port61at this position in the up-down direction7is a direction away from the first reservoir53.

Air Communication Portion70

As shown inFIGS. 5, 11, 12A, and 12B, the air communication portion70includes a buffer tank90, communication flow paths145, and an air communication path147.

As shown inFIGS. 5 and 11, the buffer tank90is located under the installation case71and above the subtank100.

As shown inFIGS. 5 and 11, the buffer tank90includes an upper wall91, a lower wall92, two side walls93, three partition walls94, a rear wall95, and an upright wall96. The upper wall91extends along a plane inclined with respect to the horizontal plane. The lower wall92extends in parallel with the horizontal plane in the rear part and curves upward as it extends forward. The lower wall92has a front end connected to the front end of the upper wall91. The two side walls93connect the upper wall91and the lower wall92in the up-down direction7at both ends of the upper and lower walls in the left-right direction9. The three partition walls94are arranged in the left-right direction9in parallel with the two side walls93. The rear wall95connects the rear end of the upper wall91and the rear end of the lower wall92. The upright wall96extends upward from the rear end of the upper wall91. The rear wall95and the upright wall96have a gap between them in the front-back direction8.

The upper wall91of the buffer tank90is located below the lower wall73of the installation case71. The upper wall91of the buffer tank90supports the lower wall73of the installation case71. Thus, the upper wall91of the buffer tank90can support the ink cartridge50housed in the installation case71with the lower wall73of the installation case71.

The internal space defined by the upper wall91, the lower wall92, the two side walls93, and the rear wall95is partitioned by the three partition walls94into four buffer chambers97. The four buffer chambers97are each connected to and communicate with the corresponding one of the four subtanks100. Each of the four buffer chambers97is a storage space for air delivered to the first reservoir53as the ink in the first reservoir53is fed to the second reservoir105by gas-liquid displacement. The four buffer chambers97are located above the recorder24.

As shown inFIG. 5, the first reservoir53is located above the buffer chamber97, and the buffer chamber97is located above the second reservoir105. The part of the first reservoir53formed in the protrusion65and a part of the buffer chamber97are arranged coaxially in the front-back direction8(an example of the horizontal direction). In addition, a part of the protrusion65, a part of the joint102, and a part of the buffer tank90are arranged coaxially in the front-back direction8(an example of the horizontal direction). Additionally, a part of the first reservoir53and a part of the buffer chamber97are arranged coaxially in the up-down direction7.

Communication Flow Path145

As shown inFIG. 12A, the lower wall92of the buffer tank90has openings98communicating with the buffer chambers97. The ink feeder15includes connection pipes99connecting the air communication ports106in the tank bodies101and the openings98in the buffer tank90. The connection pipes99are cylindrical. The inner surface of each connection pipe99defines a communication flow path145connecting the second reservoir105and the buffer chamber97. The communication flow path145extends in the up-down direction7.

Air Communication Path147

As shown inFIG. 12B, the upper wall91has an opening146at its rear end in each buffer chamber97. The upper wall91has four openings146behind the upright wall96. The bottom surface of the upper wall91is inclined upward in the front-back direction8(an example of the horizontal direction) away from the openings98(rearward). The openings146are formed in the upper wall91at the highest position of the bottom surface of the upper wall91in the up-down direction7. The front surface of the rear wall95and the rear surface of the upright wall96define an air communication path147extending in the up-down direction7. The air communication path147extends through the opening146upward from the buffer chamber97, and communicates with the outside of the housing14of the multifunction peripheral10.

Operation in Present Embodiment

The flow of ink and air at the initial loading of an ink cartridge50into an empty subtank100will now be described.

Before initially loaded (or in an unloaded state) as shown inFIG. 6, the ink cartridge50is separate from the subtank100. In the unloaded state, the communication port61of the ink cartridge50is closed by the plug62, and the first reservoir53is sealed in the ink cartridge50. Thus, ink filling the first reservoir53does not flow outside. In the unloaded state, the upper opening125and the lower opening126(seeFIG. 7) of the subtank100are closed by the plug120. Thus, the second opening132of the liquid flow path103and the fourth opening142of the gas flow path104communicating with the second reservoir105are closed to the outside. The second reservoir105includes, in addition to the liquid flow path103and the gas flow path104, the air communication port106(seeFIG. 7) and the communication port129(seeFIG. 7) for communicating with the outside. The air communication port106communicates with the air outside the multifunction peripheral10through the buffer chamber97. The communication port129communicates with the recording head39through the ink tube32. However, when the recording head39is idle, no ink flows out through the communication port129. In this state, the second reservoir105contains no ink and is empty.

As shown inFIGS. 5 and 7, when the ink cartridge50is installed in the subtank100, the plug62closing the communication port61moves forward against the urging force of the spring63, and the plug120closing the upper opening125and the lower opening126moves rearward against the urging force of the spring121. As a result, the first reservoir53communicates with the second reservoir105through the liquid flow path103and the gas flow path104. In this state, the ink in the first reservoir53of the ink cartridge50falls freely through the liquid flow path103and enters the second reservoir105of the subtank100. With the air communication port106open to the outside air, air with the same volume as the ink entering the second reservoir105flows into the first reservoir53through the air communication port106and the gas flow path104. In this manner, the ink in the first reservoir53is fed to the second reservoir105as the ink in the first reservoir53is replaced by air (gas-liquid displacement).

As the gas-liquid displacement proceeds, the liquid level of the ink in the second reservoir105increases. When the liquid level of the ink increases and reaches the lower end position of the vertical wall115, the third opening141of the gas flow path104is closed. In this state, the gas-liquid displacement no longer proceeds, thus stopping the ink feeding from the first reservoir53to the second reservoir105. The ink is fed in this manner at the initial loading.

The flow of ink and air during a recording operation performed by the printer unit11with the ink cartridge50in the installed state will now be described.

When the recording head39discharges ink during the recording operation, the ink in the second reservoir105is drawn to the recording head39through the communication port129. The liquid level of the ink in the second reservoir105lowers as the ink decreases, thus opening the closed third opening141of the gas flow path104. When the third opening141of the gas flow path104is open, the gas-liquid displacement is performed in the manner described above to feed ink from the first reservoir53to the second reservoir105. To supplement ink used in the recording head39, ink is fed from the first reservoir53to the second reservoir105. The liquid level of the ink in the second reservoir105remains at the position of the third opening141of the gas flow path104.

When the ink in the first reservoir53is used up, the empty ink cartridge50can be replaced with another ink cartridge50filled with ink to allow the multifunction peripheral10to continue the recording operation.

As shown inFIG. 13, the controller230includes a central processing unit (CPU)231, a read-only memory (ROM)232, a random-access memory (RAM)233, an electrically programmable read-only memory (EEPROM)234, and an application-specific integrated circuit (ASIC)235. The ROM232stores various programs to be executed by the CPU231to control various operations. The RAM233provides a storage area for temporarily storing data or signals used by the CPU231executing the programs or a work area used for processing data. The EEPROM234stores setting information to be retained after the power is shut off. The ROM232, the RAM233, and the EEPROM234are examples of a device memory.

The ASIC235is used to operate the feed roller25, the conveyance roller34, the discharge roller36, and the recording head39. The controller230rotates the feed roller25, the conveyance roller34, and the discharge roller36by driving a motor (not shown) through the ASIC235. The controller230further outputs a driving signal to a driving element of the recording head39through the ASIC235to cause the recording head39to discharge ink through the nozzles40. The ASIC235can output different driving signals depending on the amount of ink to be discharged through the nozzles40.

The display17and the operation panel22are connected to the ASIC235.

The contact152, the cover sensor88, the installation sensor154, and the liquid level sensor155are also electrically connected to the ASIC235. The controller230accesses the memory of the IC chip66of the ink cartridge50installed in the installation case71through the contact152. The controller230detects the position of the cover48with the cover sensor88. The controller230also detects the ink cartridge50installed in the installation case71based on a detection signal from the installation sensor154. The controller230further detects the liquid level of the ink stored in the second reservoir105equal to or higher than the predetermined level B with the liquid level sensor155.

When the liquid level sensor155outputs a high-level signal, the ROM232stores a predetermined ink amount Vsc stored in the second reservoir105of the subtank100and a predetermined ink amount Vcc stored in the first reservoir53of the ink cartridge50. The predetermined ink amount Vcc is zero in the present embodiment.

The EEPROM234stores various items of information associated with the four ink cartridges50installed in the installation case71, in other words, associated with the subtanks100communicating with the ink cartridges50. The various items of information include, for example, ink amounts Vc and Vs, which are examples of the liquid amount, a volume Vth, a flag C_Empty, a flag S_Empty, a temporary canceling flag, a non-residual ink flag, a count value SN1, a count value SN2, a count value TN, a threshold value Nth1, a threshold value Nth2, a threshold value Vmin, and a wait time Tw.

The ink amount Vc and the identification information are read by the controller230from the memory of the IC chip66through the contact152while the ink cartridge50is installed in the installation case71. The volume Vthmay be stored in the ROM232instead of the EEPROM234. The initial ink amount Vc0is an example of initial information.

The ink amount Vc indicates the amount of ink stored in the first reservoir53of the ink cartridge50. The ink amount Vs indicates the amount of ink stored in the second reservoir105of the subtank100. The ink amounts Vc and Vs are calculated based on, for example, the volume Vth. When the first reservoir53of the ink cartridge50contains ink that can flow into the subtank100, the liquid level of the ink in the second reservoir105of the subtank100is at the position of the imaginary line L including the third opening141of the gas flow path104. This state is referred to as the equilibrium state. More specifically, in the equilibrium state, ink transfer stops between the first reservoir53and the second reservoir105. The ink amount Vs in the equilibrium state is the volume Vthof the second reservoir105lower than the imaginary line L. Thus, once the total amount Vt of ink is calculated, the ink amount Vs and the ink amount Vc can be calculated. More specifically, when the total amount Vt is equal to or greater than the volume Vth, the ink amount Vs is the volume Vth, and the ink amount Vc is obtained by subtracting the volume Vthfrom the total amount Vt. When the total amount Vt is smaller than the volume Vth, the ink amount Vs is equal to the total amount Vt, and the ink amount Vc is zero. The ink amounts Vc and Vs may be determined by referring to a table storing the correspondence between the ink amounts and the total amount Vt without using the volume Vth.

The count value SN1is equivalent to an ink discharge amount Dh (an ink amount indicated by a driving signal) instructed to discharge through the recording head39after the signal output from the liquid level sensor155changes from a low level to a high level and is updated toward the threshold value Nth1. The count value SN1is counted up from an initial value of 0. The threshold value Nth1is equivalent to the volume of a part of the second reservoir105between the position near the upper end of the communication port129and the predetermined level B. However, the count value SN1may be counted down from an initial value equivalent to the volume. In this case, the threshold value Nth1is zero (0). The count value SN1is an example of a first count value. The threshold value Nth1is an example of a first threshold.

The count value SN2is equivalent to an ink discharge amount Dh (an ink amount indicated by a driving signal) instructed to discharge through the recording head39when the flag S_Empty is OFF and the signal output from the liquid level sensor155is a high-level signal, and is updated toward the threshold value Nth2. The count value SN2is counted up from an initial value of 0. Further, the threshold value Nth2is equivalent to the product of the average amount of ink discharged through the recording head39and the number of unit sheets that can undergo image recording within the wait time Tw (described later) in the image recording operation for the unit sheet (one sheet). However, the count value SN2may be counted down from an initial value equivalent to the product. In this case, the threshold value Nth2is zero (0). The count value SN2is an example of a second count value. The threshold value Nth2is an example of a second threshold. In the present embodiment, the threshold value Nth1is greater than the threshold value Nth2. However, the relationship between the threshold value Nth1and the threshold value Nth2is set in accordance with the size of the second reservoir105of the subtank100, the inflow rate from the first reservoir53of the ink cartridge50to the second reservoir105, and the liquid level of the ink detected by the liquid level sensor155.

The count value TN is equivalent to an ink discharge amount Dh (an ink amount indicated by a driving signal) instructed to discharge through the recording head39after the signal output from the liquid level sensor155changes from a high level to a low level, and is counted up from an initial value of 0. The count value TN may be counted down from an initial value equivalent to the total amount Vt of ink as well.

The flag C_Empty is information indicating whether the ink cartridge50is in a cartridge empty state. The flag C_Empty is set either ON corresponding to the cartridge empty state or OFF corresponding to a non-cartridge empty state. The cartridge empty state refers to the state of the ink cartridge50(more specifically, the first reservoir53) storing substantially no ink. In other words, the cartridge empty state refers to the state of no ink transferred from the first reservoir53to the second reservoir105communicating with each other. The liquid level sensor155detects this cartridge empty state when the liquid level of the subtank100communicating with the ink cartridge50is lower than the predetermined level B.

The flag S_Empty is information indicating whether the subtank100is in the empty ink state. The flag S_Empty is set either ON corresponding to the empty ink state or OFF corresponding to a non-empty ink state. The empty ink state refers to, for example, the state of the liquid level of the ink stored in the subtank100(more specifically, the second reservoir105) reaching the position near the upper end of the communication port129. In other words, the empty ink state refers to the state of the count value SN1equal to or greater than the threshold value Nth1. When the ink continues to be discharged through the recording head39in the empty ink state, the liquid level of the ink in the subtank100may fall below the upper end of the communication port129, and air may mix in an ink flow path from the subtank100to the recording head39or in the recording head39(air entrapment). The nozzles40may not be filled with the ink, and the ink may not be discharged.

The temporary canceling flag is information indicating whether the signal output from the liquid level sensor155remains at a high level after the ink cartridge50is replaced and the flag C_Empty and the flag S_Empty are both set OFF. The temporary canceling flag is set either ON corresponding to the state of the signal output from the liquid level sensor155remaining at a high level or OFF corresponding to the state of the signal changed to a low level. When the ink continues to be discharged through the recording head39while the signal output from the liquid level sensor155remains at a high level or in the temporary canceling state, air entrapment may occur as described above.

The non-residual ink flag is information indicating whether the liquid level of the ink stored in the second reservoir105of the subtank100is lowered to the upper end of the communication port129. When the liquid level of the ink stored in the second reservoir105reaches a position near the upper end of the communication port129, the tank is in an empty ink state. Although the empty ink state is determined depending on whether the count value SN1is equal to or greater than the threshold value Nth1, the liquid level of the ink stored in the second reservoir105in the empty ink state may be set at a position substantially higher than the upper end of the communication port129, reflecting any error of the count value SN1or the position of the liquid level of the ink stored in the second reservoir105affected by the installed state (inclination from the horizontal direction) of the multifunction peripheral10.

In contrast, when the total amount Vt, which is the sum of the ink amount Vc stored in the replaced ink cartridge50and the ink amount Vs stored in the second reservoir105of the subtank100, is equal to or greater than the threshold value Vmin, the ink is transferred from the first reservoir53to the second reservoir105, and the liquid level of the ink in the second reservoir105reaches the predetermined level B over a predetermined time. The liquid level of the ink stored in the second reservoir105in the empty ink state is to be positioned above the upper end of the communication port129by the degree equivalent to the amount of ink to be used for image recording on the number N of sheets during the predetermined time until the liquid level of the ink reaches the predetermined level B. Under this setting, the liquid level of the ink stored in the second reservoir105does not reach the upper end of the communication port129although no ink is transferred from the first reservoir53to the second reservoir105after image recording is performed the number of times corresponding to the number N of sheets described above.

However, when image recording has been performed for the number N of sheets described above in the temporary canceling state but the empty state has not been fully canceled, the liquid level of the ink stored in the second reservoir105may be already lowered to near the upper end of the communication port129despite the ink cartridge50replaced again. When the ink continues to be discharged through the recording head39, air entrapment occurs as described above. The OFF value of the non-residual ink flag is an example of a first value, and the ON value of the flag is an example of a second value.

Operation of Multifunction Peripheral10

The operation of the multifunction peripheral10according to the present embodiment will be described with reference toFIGS. 14 to 18. Each of the processes shown inFIGS. 14 to 18is performed by the CPU231of the controller230. Each of the processes described below may be performed by the CPU231reading programs stored in the ROM232, or may be implemented by a hardware circuit installed in the controller230. Further, the processes described below can be performed in an order changed appropriately without departing from the spirit and scope of the present disclosure.

Image Recording Process

The controller230performs an image recording process shown inFIG. 14in response to a recording instruction input to the multifunction peripheral10. The recording instruction is an example of a discharge instruction for causing the multifunction peripheral10to record an image represented by image data on a sheet. The recording instruction may be received in any manner, but may be received as a corresponding user operation performed through the operation panel22or may be received from an external device through a communication interface (not shown).

First, the controller230determines the set values for the four flags S_Empty (S11). When determining that at least one of the four flags S_Empty is set ON (S11: ON), the controller230displays a notification screen S_Empty on the display17(S12). The notification screen S_Empty notifies the user that the corresponding subtank100is in the empty ink state and the ink cannot be discharged through the recording head39. For example, the notification screen S_Empty may include information indicating the color and the ink amounts Vc and Vs of the ink stored in the subtank100in the empty ink state. In step S12, the controller230may display the notification screen C_Empty on the display17together with the notification screen S_Empty when determining that at least one of the four flags C_Empty is set ON. The operation of the display17in step S12is an example of a first operation.

The controller230also performs the processing in steps S13to S15for each ink cartridge50corresponding to the flag S_Empty set ON. More specifically, the processing in steps S13to S15is performed for each ink cartridge50for which the flag S_Empty is set ON, among the four ink cartridges50. The processing in steps S13to S15is common to the ink cartridges50. The processing in steps S13to S15corresponding to one ink cartridge50will be described.

The controller230first obtains a signal output from the installation sensor154(S13). The controller230then determines whether the signal obtained from the installation sensor154is a high-level signal or a low-level signal (S14). Then, the controller230repeatedly performs the processing in steps S13and S14at predetermined time intervals until the signal output from the installation sensor154changes from a low level to a high level and then from a high level to a low level again (S14: No). In other words, the controller230repeatedly performs the processing in steps S13and S14until the ink cartridge50is removed from the installation case71and an ink cartridge50is newly installed in the installation case71.

The controller230obtains a high-level signal from the installation sensor154after obtaining a low-level signal from the installation sensor154. Subsequently, in response to another low-level signal obtained from the installation sensor154(S14: Yes), the controller230determines whether the non-residual ink flag is ON (S15). When the non-residual ink flag is ON (S15: Yes), the controller230performs a process described below (seeFIG. 18). The controller230also stores, into the EEPROM234, the time at which the low-level signal is obtained from the installation sensor154after the high-level signal is obtained from the installation sensor154. The controller230may measure the time by operating a timer after obtaining the low-level signal from the installation sensor154, instead of storing the time. The stored time or the measured time is used in an empty-state fully canceling process (described below).

When the non-residual ink flag is OFF (S15: No), the controller230performs the empty-state temporary canceling process (S16). The empty-state temporary canceling process is to delete the notification screen C_Empty and the notification screen S_Empty appearing on the display17. The empty-state temporary canceling process will be described in detail with reference toFIG. 16. The processing subsequent to step S11is resumed in response to the completion of the empty-state temporary canceling process.

When the flags S_Empty corresponding to all the ink cartridges50are all not ON, or in other words, are all OFF, the controller230obtains signals output from the four liquid level sensors155at the current time (S17). In step S17, the controller230further causes the RAM233to store information indicating whether the signal obtained from each liquid level sensor155is a high-level signal or a low-level signal.

The controller230then records the image represented by the image data included in the recording instruction on one sheet (S18). More specifically, the controller230causes the sheet on the feed tray20to be conveyed by the feed roller25and the conveyance roller34, the recording head39to discharge the ink, and the sheet having the recorded image to be discharged to the discharge tray21with the discharge roller36. More specifically, the controller230enables the ink discharge through the recording head39when all the four flags S_Empty are set OFF. In contrast, the controller230disables the ink discharge through the recording head39when at least one of the four flags S_Empty is set ON.

The controller230then obtains signals output from the four liquid level sensors155at the current time upon recording the image on one sheet in response to the recording instruction (S19). Similarly to step S17, the controller230causes the RAM233to store information indicating whether the signal obtained from each liquid level sensor155is a high-level signal or a low-level signal (S19). The controller230then performs a counting process (S20). The counting process is to update the count values TN, SN1, and SN2, the flag C_Empty, and the flag S_Empty based on the signals obtained from each liquid level sensor155in steps S17and S19. The counting process will be described in detail below with reference toFIG. 15.

The controller230then repeatedly performs the processing in steps S11to S20until all the images indicated by the recording instruction are recorded on one sheet (S21: Yes). After recording all the images indicated by the recording instruction on one sheet (S21: No), the controller230determines the set values for the four flags S_Empty and the set values for the four flags C_Empty (S22and S23).

When at least one of the four flags S_Empty is set ON (S22: ON), the controller230displays the notification screen S_Empty on the display17(S24). When all the four flags S_Empty are set OFF and at least one of the four flags C_Empty is set ON (S22: OFF and S23: ON), the controller230displays the notification screen C_Empty on the display17(S25). The processing in steps S24and S25is an example of activating the alarm.

The notification screen S_Empty displayed in step S24may be the same as in step S12. The notification screen C_Empty notifies the user that the ink cartridge50corresponding to the flag C_Empty set ON is in the cartridge empty state. For example, the notification screen C_Empty may include information indicating the color and the ink amounts Vc and Vs of the ink stored in the ink cartridge50in the cartridge empty state. In contrast, when all the four flags S_Empty and the four flags C_Empty are set OFF (S23: OFF), the controller230completes the image recording process without performing the processing in steps S24and S25.

An example of the discharge instruction is not limited to the recording instruction, but may be a maintenance instruction instructing maintenance of the nozzles40such as a purge. For example, the controller230performs the same process as inFIG. 14in response to a maintenance instruction obtained through the operation panel22. The process in response to a maintenance instruction differs from the above process in the manner described below. First, the controller230drives a maintenance mechanism (not shown) in step S18, and discharges the ink through the nozzles40. The controller230also performs the processing in steps subsequent to step S21without performing the processing in step S21after the counting process.

Counting Process

The counting process performed by the controller230in step S20will be described in detail with reference toFIG. 15. The controller230performs the counting process independently for each of the four ink cartridges50. The counting process is common to the ink cartridges50. The counting process for one ink cartridge50will be described.

First, the controller230compares sets of information indicating the signals from the liquid level sensors155stored in the RAM233in steps S17and S19(S31). More specifically, the controller230determines whether the signal from each of the four liquid level sensors155has changed before and after the processing in step S18immediately before the counting process (S20).

When the sets of information stored in the RAM233in steps S17and S19both indicate a low-level signal (S31: L→L) (in other words, the output of each liquid level sensor155remains unchanged before and after the processing in step S18) (S32), the controller230updates the count value TN (S32). More specifically, the controller230counts up the count value TN to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S18.

The controller230also calculates the current total amount Vt (S33). First, the controller230calculates the total amount Vt after the cartridge replacement that is the sum of the ink amount Vc and the ink amount Vs stored in the EEPROM234after the cartridge replacement. The controller230then calculates the current total amount Vt by subtracting the ink amount equivalent to the count value TN from the calculated total amount Vt (Vt=Vt−TN). The controller230then obtains the ink amounts Vc and Vs based on the calculated current total amount Vt and the volume Vth(S33).

The controller230then displays the obtained total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S34). Further, the controller230overwrites the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50with the obtained ink amount Vc (S35).

When the information stored in the RAM233in step S17indicates a low-level signal and the information stored in the RAM233in step S19indicates a high-level signal (S31: L→H) (in other words, the output of the liquid level sensor155is changed before and after the processing in step S18), the controller230substitutes a value indicating ON into the flag C_Empty (S36). The output from the liquid level sensors155changing from a low-level signal to a high-level signal corresponds to the liquid level of the second reservoir105reaching the predetermined level B during the processing in step S18as shown inFIG. 19A. In this state, no ink transfer occurs between the ink cartridge50and the subtank100.

The controller230also reads a predetermined ink amount Vcc (=0) from the ROM232, and sets the ink amount Vc to the predetermined ink amount Vcc (S37). Similarly, the controller230reads a predetermined ink amount Vsc (equivalent to the volume of a part of the second reservoir105lower than the predetermined level B) from the ROM232, and sets the ink amount Vs to the predetermined ink amount Vsc (S37). The ink amounts Vc and Vs calculated in the residual amount updating process include errors. The controller230thus sets the ink amount Vc to the predetermined ink amount Vcc and the ink amount Vs to the predetermined ink amount Vsc at the time when the output from the liquid level sensor155changes from a low-level signal to a high-level signal, thus resetting the accumulated errors. Further, the controller230calculates the current total amount Vt as a value equal to the ink amount Vs (Vt=Vsc) (S37). When the ink amount Vc is zero, the total amount Vt has the same value as the ink amount Vs.

The controller230then displays the current total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S38). The controller230also overwrites the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50with the above ink amount Vc (S39).

The output of each liquid level sensor155changes during the processing in step S18, and thus the predetermined ink amount Vsc read in step S37is not strictly the amount of ink stored in the subtank100at the moment when the output from the liquid level sensor155changes, but indicates the amount of ink immediately before the output from the liquid level sensor155changes. With the difference between the ink amounts being small, the ink amount Vsc read in step S37is approximately the ink amount Vs at the time when the output from the liquid level sensor155changes.

The controller230also counts up the count value SN1stored in EEPROM234to the value equivalent to the amount of ink instructed to discharge in the immediately preceding step S18(S40). In other words, the controller230starts updating the count value SN1in response to the output from the liquid level sensors155changing from a low-level signal to a high-level signal. The controller230counts up the count value TN stored in the EEPROM234to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S18.

The controller230then calculates the ink amount Vs (S41). The above ink amount Vs is obtained by subtracting the ink amount equivalent to the count value SN1stored in the EEPROM234from the predetermined ink amount Vsc stored in the ROM232. As described above, after the output from the liquid level sensor155changes to a high-level signal, the ink amount Vs is the same value as the current total amount Vt. The ink amount Vc is zero.

The controller230then displays the obtained current total amount Vt or the ink amount Vs on the display17(S42). The ink amount Vc is zero after the output of liquid level sensor155changes to a high-level signal, and thus the controller230does not overwrite the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50.

The controller230then compares the count value SN1updated in step S40with the threshold value Nth1(S43). When determining that the count value SN1updated in step S40is smaller than the threshold value Nth1(S43: No), the controller230completes the counting process. In contrast, when determining that the count value SN1updated in step S40is equal to or greater than the threshold value Nth1(S43: Yes), the controller230substitutes the value indicating ON into the flag S_Empty (S44). The controller230disables the ink discharge through the recording head39in response to the flag S_Empty set ON, and completes the counting process.

When the sets of information stored in the RAM233in steps S17and S19both indicate a high-level signal (S31: H→H), the controller230determines whether the temporary canceling flag stored in the EEPROM234is ON (S45). When the temporary canceling flag is ON (S45: No), the controller230reads the count value SN1stored in the EEPROM234. The controller230then counts up the read count value SN1to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S18and stores the value into the EEPROM234again. More specifically, the controller230updates the count value SN1(S40). The controller230also updates the count value TN. The controller230then performs the processing from steps S41to S44described above using the count value SN1updated in step S40.

When the temporary canceling flag is ON (S45: Yes), the controller230performs the empty-state fully canceling process (S46). The empty-state fully canceling process will be described in detail below with reference toFIG. 17.

Empty-State Temporary Canceling Process

With reference toFIG. 16, the empty-state temporary canceling process performed by the controller230in step S16will be described in detail. The controller230performs the empty-state temporary canceling process independently for each of the four ink cartridges50. The empty-state temporary canceling process is common to the ink cartridges50. The empty-state temporary canceling process for one ink cartridge50will be described.

In the counting process, when determining that the count value SN1is equal to or greater than the threshold value Nth1(S43: Yes), the controller230substitutes the value indicating ON into the flag S_Empty (S44) and disables the ink discharge through the recording head39. In the image recording process, when determining that the flag S_Empty is set ON (S11: ON), the controller230displays the notification screen S_Empty on the display17(S12).

In the above state (or the state of the controller230disabling the ink discharge through the recording head39and displaying the notification screen S_Empty on the display17), as shown inFIG. 19B, the ink cartridge50is in the state of no ink flowing toward the subtank100, or in the state of the ink amount Vc being zero (Vc=0). Also, the liquid level of the ink in the subtank100is lower than the predetermined level B and reaches the position near the upper end of the communication port129. Image recording cannot be performed unless the ink discharge through the recording head39is enabled by the user replacing the ink cartridge50in the empty state with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink.

In the process of replacing the ink cartridge50by the user, the controller230obtains a low-level signal from the installation sensor154, and then obtains a high-level signal from the installation sensor154, and further obtains a low-level signal from the installation sensor154(S14: Yes). More specifically, in the process of removing the ink cartridge50from the installation case71, the controller230obtains a low-level signal from the installation sensor154and then obtains a high-level signal from the installation sensor154. In the subsequent process of inserting the ink cartridge50into the installation case71, the controller230obtains a high-level signal from the installation sensor154and then obtains a low-level signal from the installation sensor154.

In the empty-state temporary canceling process, the controller230reads CTG information from the memory of the IC chip66through the contact152and stores the read CTG information into the EEPROM234(S51). When the ink cartridge50is replaced with a fresh ink cartridge50, an initial ink amount Vc0is stored as the ink amount Vc in the memory of the IC chip66. The identification information is also read from the memory of the IC chip66.

When determining that the initial ink amount Vc0is read (S52: Yes), the controller230performs the processing in step S56(described later) without performing the processing in step S53(described later). When determining that the initial ink amount Vc0is not read (S52: No), the controller230performs the processing in step S53(described later). When the initial ink amount Vc0is not read, the ink amount Vc read from the memory of the IC chip66is not the initial ink amount Vc0but is a value smaller than the initial ink amount.

The controller230compares a total amount Vt obtained by adding the ink amount Vc read from the memory of the IC chip66to the ink amount Vs read from the EEPROM234with the threshold value Vmin (S53). The threshold value Vmin equivalent to the total amount when the liquid level reaches the predetermined level B in the second reservoir105of the subtank100. When the calculated total amount Vt is equal to or greater than the threshold value Vmin (S53: Yes), the ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100and the liquid level of the ink in the second reservoir105reaches the predetermined level B or higher. In contrast, the controller230performs the processing in steps S54and S55when the calculated total amount Vt is smaller than the threshold value Vmin (S53: No).

When determining that the calculated total amount Vt is smaller than the threshold value Vmin (S53: No), the controller230substitutes a value indicating OFF into the flag S_Empty and enables the disabled discharge of ink through the recording head39(S54). The value indicating ON remains for the flag C_Empty. The controller230then deletes the notification screen S_Empty from the display17and displays the notification screen C_Empty on the display17(S55). The controller230completes the empty-state temporary canceling process.

When the calculated total amount Vt is smaller than the threshold value Vmin, the liquid level of the ink in the second reservoir105does not reach the predetermined level B or higher despite any ink transfer from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100. In this case, the user is urged to replace the ink cartridge50through a notification although image recording can be performed with the ink stored in the second reservoir105of the subtank100.

When determining that the calculated total amount Vt is equal to or greater than the threshold value Vmin (S53: Yes), the controller230compares the identification information read from the memory of the IC chip66with the identification information read from the memory of the IC chip66of the ink cartridge50yet to be replaced (S56). The identification information read from the memory of the IC chip66of the ink cartridge50yet to be replaced is stored in the EEPROM234. For example, with the ink cartridge50replaced with a fresh ink cartridge50, the compared two sets of identification information disagree with each other. The identification information is, for example, the serial number of the ink cartridge50.

When determining that the compared two sets of identification information agree with each other (S56: No), the controller230completes the empty-state temporary canceling process. When the ink cartridge50having the ink used up to have the ink amount Vc of zero in the first reservoir53is installed in the installation case71again, no ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100, and thus the empty state Empty is not to be canceled temporarily.

When determining that the compared two sets of identification information disagree with each other (S56: Yes), the controller230stores the count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the EEPROM234into another storage area of the EEPROM234(S57). The count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the other memory area of the EEPROM234are used when the empty state is not fully canceled after the empty state Empty is temporarily canceled as described later.

After step S57, the controller230calculates the total amount Vt after the cartridge replacement (S58). In detail, the controller230calculates the ink amount Vs before the cartridge replacement (equal to the total amount Vt) based on the count value SN1before the cartridge replacement stored in the EEPROM234and a predetermined ink amount Vsc stored in the ROM232, and stores the ink amount into the EEPROM234. Based on the calculated ink amount Vs and the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50, the total amount Vt after the cartridge replacement is calculated. More specifically, the ink amount Vc stored in the first reservoir53of the fresh ink cartridge50is added to the ink amount Vs stored in the second reservoir105of the subtank100immediately before the ink cartridge50is replaced. The controller230thus calculates the sum of the ink amount Vc read from the IC chip66of the replaced ink cartridge50and the ink amount Vs before the cartridge replacement stored in the EEPROM234as the total amount Vt (Vt=Vs+Vc). The ink amounts Vc and Vs are calculated from the calculated total amount Vt of ink based on the volume Vth.

The count values TN and SN1stored in the EEPROM234are reset (S59). This sets the count values TN and SN1to their initial values (zero).

The controller230then displays the obtained current total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S60). The controller230stores the calculated ink amount Vc into the memory of the IC chip66through the contact152(S61). When the initial ink amount Vc0as the ink amount Vc is stored in the memory of the IC chip66, the controller230overwrites the initial ink amount Vc0with the calculated ink amount Vc. With the ink amount Vc overwritten in the memory of the IC chip66, the ink cartridge50is determined not to be a fresh ink cartridge. In the manufacturing processes, a flag indicating that the ink cartridge50is a fresh ink cartridge may be set ON in the memory of the IC chip66. Once the ink cartridge50is installed in the installation case71, the controller230may substitute the value indicating OFF into the flag. The controller230can thus determine whether the ink cartridge50is a fresh ink cartridge based on the value of the flag.

The controller230substitutes the value indicating OFF into each of the flag S_Empty and the flag C_Empty (S62). The controller230substitutes the value indicating ON into the temporary canceling flag (S63). The controller230enables the ink discharge through the recording head39when all the four flags S_Empty are set OFF. The controller230deletes the notification screen S_Empty and the notification screen C_Empty from the display17(S64), and completes the empty-state temporary canceling process.

Empty-State Fully Canceling Process

With reference toFIG. 17, the empty-state fully canceling process performed by the controller230in step S46will be described in detail. The controller230performs the empty-state fully canceling process independently for each of the four ink cartridges50. The empty-state fully canceling process is common to the ink cartridges50. The empty-state canceling process for one ink cartridge50will be described.

When determining that the temporary canceling flag is ON in the counting process (S45: Yes), the controller230performs the empty-state fully canceling process. At this time, the flag S_Empty is OFF and the ink discharge through the recording head39is enabled. The notification screen S_Empty is not on the display17. The user can use the multifunction peripheral10in the same manner as in the normal use state.

As shown inFIG. 20, when the temporary canceling flag is ON, the ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100and the liquid level of the ink in the second reservoir105is lower than the predetermined level B. When the processing in step S18is performed in this state, the controller230counts up the count value SN2stored in the EEPROM234to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S18(S70). In other words, the controller230starts updating the count value SN2in response to the temporary canceling flag set ON. The controller230counts up the count value TN stored in the EEPROM234to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S18.

The controller230then calculates the current total amount Vt (S71). First, the controller230calculates the total amount Vt after the cartridge replacement as the sum of the ink amount Vc and the ink amount Vs stored in the EEPROM234. The controller230then calculates the current total amount Vt by subtracting the ink amount equivalent to the count value TN from the total amount Vt after the cartridge replacement. The controller230obtains the ink amounts Vc and Vs based on the calculated current total amount Vt and the volume Vth(S71).

The controller230then displays the obtained current total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S72). Further, the controller230overwrites the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50with the obtained ink amount Vc (S73).

The controller230then determines whether the output from the liquid level sensor155is a low-level signal (S74). When determining that the output from the liquid level sensor155is a low-level signal (S74: Yes), the controller230substitutes the value indicating OFF into each of the temporary canceling flag and the non-residual ink flag (S75and S76).

When determining that the output from the liquid level sensor155is not a low-level signal but is a high-level signal (S74: No), the controller230compares the count value SN2updated in step S70with the threshold value Nth2(S77).

When determining that the count value SN2updated in step S70is smaller than the threshold value Nth2(S77: No), the controller230determines whether a wait time Tw has elapsed from the time stored in the EEPROM234in the image recording process (the time when the low-level signal is obtained after the high-level signal is obtained from the installation sensor) (S78). The wait time Tw is set by a wait time Tw setting process described later.

When determining that the wait time Tw has not elapsed from the time stored in the EEPROM234(S78: No), the controller230completes the empty-state fully canceling process.

When determining that the wait time Tw has elapsed from the time stored in the EEPROM234(S78: Yes), the controller230substitutes the value indicating ON into the flag S_Empty (S79). The controller230then disables the ink discharge through the recording head39in response to the flag S_Empty set ON. The controller230displays the notification screen S_Empty on the display17(S80).

In the empty-state temporary canceling state, the total amount Vt that is the sum of the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50and the ink amount Vs of the second reservoir105of the subtank100is equal to or greater than the threshold value Vmin. However, when the ink amount Vc stored in the memory of the IC chip66is larger than the amount of ink substantially stored in the ink cartridge50or the ink transfer from the ink cartridge50to the subtank100is disabled, the liquid level of the ink is not raised to the predetermined level B in the second reservoir105of the subtank100. In this case, the user may be urged to replace the ink cartridge50again with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink, and the ink discharge through the recording head39is to be disabled until the ink cartridge50is replaced again.

The controller230reads the count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the other area of the EEPROM234(S81) and updates the count values TN and SN1, the ink amount Vc, and the ink amount Vs currently stored in the EEPROM234to the read values (S82). More specifically, the count value SN2is added to each of the count values TN and SN1stored in the other area of the EEPROM234, and the resultant values are stored into the EEPROM234. The controller230updates the ink amount Vc stored in the EEPROM234to zero. Further, the controller230substitutes the value indicating OFF into the temporary canceling flag (S83), and completes the empty-state fully canceling process. This ends the empty-state temporary canceling state, thus setting the empty ink state immediately before temporarily canceling the empty state Empty. The updated count value SN1, more specifically, the sum of the stored count values SN1and SN2, corresponds to a third count value.

When determining that the count value SN2updated in step S70is equal to or greater than the threshold value Nth2(S77: Yes), the controller230substitutes the value indicating ON into the non-residual ink flag (S84). When the count value SN2is equal to or greater than the threshold value Nth2for a predetermined time until the liquid level of the ink in the second reservoir105of the subtank100reaches the predetermined level B, the ink is discharged through the recording head39by the amount of ink corresponding to the number N of sheets to undergo image recording.

The controller230displays a screen for notifying that the ink is flowing into the subtank100from the ink cartridge50on the display17(S85). The controller230determines whether the wait time Tw has elapsed from the time stored in the EEPROM234(S86). When determining that the wait time Tw has not elapsed from the time stored in the EEPROM234(S86: No), the controller230continuously displays the above screen on the display17. More specifically, until the wait time Tw elapses from the time stored in the EEPROM234, the image recording process in the next step S18is suspended. The operation performed by the display17in step S86is an example of a second operation.

When determining that the wait time Tw has elapsed from the time stored in the EEPROM234(S86: Yes), the controller230determines whether the signal output from the liquid level sensor155is a low-level signal (S87). When determining that the signal output from the liquid level sensor155is a low-level signal (S87: Yes), the controller230performs the processing from steps S75to S76described above, and completes the empty-state fully canceling process. The signal output from the liquid level sensor155being the low-level signal indicates that the ink is transferred from the ink cartridge50to the subtank100, and the liquid level of the ink in the second reservoir105reaches the predetermined level B before the wait time Tw elapses from the time stored in the EEPROM234. This ends the empty-state temporary canceling state.

In contrast, when determining that the signal output from the liquid level sensor155is not a low-level signal but is a high-level signal (S87: No), the controller230performs the processing from steps S79to S83described above, and ends the empty-state fully canceling process. This ends the empty-state temporary canceling state, thus setting the empty ink state immediately before temporarily canceling the empty state Empty.

When determining that the non-residual ink flag is ON in step S15in the image recording process (S15: Yes), the controller230performs the process shown inFIG. 18. As described above, when the ink amount Vc stored in the memory of the IC chip66is larger than the amount of ink substantially stored in the ink cartridge50or the ink transfer from the ink cartridge50to the subtank100is disabled, the liquid level of the ink in the second reservoir105of the subtank100is not raised to the predetermined level B. In this case, the ink cartridge50is to be replaced again with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink.

However, when the non-residual ink flag is ON, the count value SN2updated in step S70is already equal to or greater than the threshold value Nth2. Thus, although the ink cartridge50is replaced again, image recording performed in the empty-state temporary canceling state may cause air entrapment described above. When determining that the non-residual ink flag is ON (S15: Yes), the controller230does not perform the empty-state temporary canceling process.

As shown inFIG. 18, when determining that the non-residual ink flag is ON (S15: Yes), the controller230displays the screen notifying that the ink is flowing into the subtank100from the ink cartridge50on the display17(S90).

The controller230determines whether the signal output from the liquid level sensor155is a low-level signal (S91). When determining that the signal output from the liquid level sensor155is not a low-level signal but a high-level signal (S91: No), the controller230repeatedly performs the processing in step S91until the signal output from the liquid level sensor155changes to a low-level signal.

When determining that the signal output from the liquid level sensor155is a low-level signal (S91: Yes), the controller230calculates the ink amount Vs before the cartridge replacement (equal to the total amount Vt) based on the count value SN before the cartridge replacement stored in the EEPROM234and the ink amount Vsc stored in the ROM232, and stores the calculated value into the EEPROM234. Based on the calculated ink amount Vs and the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50, the total amount Vt after the cartridge replacement is calculated (S92: Vt=Vs+Vc).

The controller230calculates the ink amount Vc and the ink amount Vs when ink transfer from the first reservoir53to the second reservoir105is complete based on the calculated total amount Vt and the volume Vthread from the EEPROM234(S92).

The controller230resets the count values TN, SN1, and SN2stored in the EEPROM234(S93). This sets the count values TN, SN1, and SN2to their initial values (zero).

The controller230then displays the obtained current total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S94). The controller230stores the calculated ink amount Vc into the memory of the IC chip66through the contact152(S95).

The controller230substitutes the value indicating OFF into each of the non-residual ink flag, the flag S_Empty, and the flag C_Empty (S96and S97). The controller230enables the ink discharge through the recording head39when all the four flags S_Empty are set OFF. The controller230deletes the notification screen S_Empty and the notification screen C_Empty from the display17(S98) and returns to step S17. Thus, when the non-residual ink flag is set ON, which can cause air entrapment described above if more ink is discharged through the recording head39, the empty ink state is canceled without temporarily canceling the empty ink state in response to the output from the liquid level sensor155indicating that the liquid level of the ink in the second reservoir105of the subtank100reaches the predetermined level B. This prevents air entrapment described above.

Wait Time Tw Setting Process

With reference toFIG. 21, the wait time Tw setting process performed by the controller230will be described in detail. The controller230performs the wait time Tw setting process independently for each of the four ink cartridges50. The wait time Tw setting process is common to the ink cartridges50. The wait time Tw setting process for one ink cartridge50will be described.

The controller230performs the wait time Tw setting process when the ink cartridge50is installed firstly in the installation case71of the multifunction peripheral10. The controller230determines whether the ink cartridge50is installed firstly in the installation case71based on, for example, identification information read from the IC chip66of the installed ink cartridge50indicating that the cartridge has been packaged with the multifunction peripheral10, or a flag indicating an initial ink loading operation not stored in the EEPROM234. The determination causes the time to be measured from when the ink flows into the second reservoir105of the subtank100in the empty state to when the liquid level of the ink reaches the predetermined level B.

As shown inFIG. 21, the controller230stores, into the EEPROM234, the time when the ink cartridge50is installed firstly in the installation case71, or in other words, the time when a low-level signal is obtained from the installation sensor154after a high-level signal is obtained from the installation sensor154. The controller230then calculates, in response to the signal received from the liquid level sensor155changing from a high level to a low level, a time T0 from the time stored in the EEPROM234to when the signal from the liquid level sensor155changes (S101). The time T0 is an example of a second elapsed time.

When a fresh ink cartridge50is installed in the installation case71, the ink flows from the first reservoir53into the second reservoir105. The liquid level of the ink in the second reservoir105then reaches the predetermined level B over time, and thus the liquid level sensor155outputs a low-level signal.

Subsequently, the controller230calculates a difference between the calculated time T0 and a design value Ts prestored in the EEPROM234(|Ts−T0|) and determines whether the calculated difference is within a threshold value range X (S102: X≥|Ts−T0|). When the calculated difference is within the threshold value range X (S102: Yes), the controller230stores, into the EEPROM234, the time obtained by adding a predetermined additional time to the time T0 as the wait time Tw (S103). When the calculated difference is out of the threshold value range X (S102: No), the controller230stores, into the EEPROM234, the time obtained by adding a predetermined additional time to the predetermined design value Ts as the wait time Tw (S104).

Operational Effects of First Embodiment

The structure according to the first embodiment can cancel the empty ink state, in which the ink discharge through the recording head39is disabled, after the ink cartridge50is replaced and before the liquid level sensor155outputs a low-level signal. When the elapsed time from the replacement of the ink cartridge50reaches the wait time Tw after the empty ink state is canceled, the empty ink state is entered, in which the ink discharge through the recording head39is disabled. In this state, air from the second reservoir105of the subtank100is prevented from entering the recording head39although the ink cartridge50installed in the installation case71does not store an amount of ink in the first reservoir53sufficient to cause the liquid level of the ink in the second reservoir105of the subtank100to reach the predetermined level B or higher.

When the elapsed time from the replacement of the ink cartridge50reaches the wait time Tw and the empty ink state is entered, the count value SN2is updated by adding the count value SN2to the count value SN1used before the state S_Empty is canceled.

In the empty ink state, the previously disabled ink discharge through the head can be enabled after the ink cartridge50is replaced with a fresh ink cartridge50and before the liquid level sensor155outputs a low-level signal.

Further, the notification screen S_Empty on the display17can notify the user that the ink discharge through the recording head39is disabled.

Without a fresh ink cartridge50replacing the ink cartridge50, the empty ink state can be canceled before the liquid level sensor155outputs a low-level signal when the ink cartridge50installed in the installation case71stores an amount of ink in the first reservoir53sufficient to cause the liquid level of the ink in the second reservoir105of the subtank100to reach the predetermined level B or higher.

Further, when the ink cartridge50installed in the installation case71does not store an amount of ink in the first reservoir53sufficient to cause the liquid level of the ink in the second reservoir105of the subtank100to reach the redetermined position B or higher, the notification screen C_Empty appears on the display17to urge the user to replace the ink cartridge50with a fresh ink cartridge50.

When the sum of the count value SN2and the count value SN1reaches the threshold value Nth2after the empty ink state is canceled, the empty ink state is entered, and thus the controller230can limit the amount of ink discharged through the recording head39before receiving a low-level signal from the liquid level sensor155. This prevents air from the second reservoir105from entering the recording head39. Subsequently, the empty ink state is canceled in response to a low-level signal from the liquid level sensor155, enabling the disabled discharge of ink through the recording head39.

The wait time Tw is set in accordance with the elapsed time from when the ink cartridge50is installed firstly in the installation case71to when the liquid level sensor155outputs a low-level signal, and can thus be set in accordance with differences between individual devices.

When the temporary canceling state is entered or the temporary canceling flag is ON, the controller230substitutes the value indicating OFF into the temporary canceling flag in response to a low-level signal from the liquid level sensor155. Thus, when the liquid level of the second reservoir105is substantially equal to or higher than the predetermined level B after the cartridge is replaced, the temporary canceling state is canceled. The controller also substitutes the value indicating OFF into the non-residual ink flag as well when the liquid level of the second reservoir105is substantially equal to or higher than the predetermined level B after the cartridge is replaced. This prevents air entrapment described above.

Modifications of First Embodiment

The empty-state temporary canceling process in the first embodiment includes the determination (S52) as to whether the ink cartridge50installed in the installation case71stores the initial ink amount Vc0, or in other words, as to whether the ink cartridge50is a fresh ink cartridge50, or the determination (S53) as to whether the total amount Vt that is the sum of the ink amount Vc of the first reservoir53and the ink amount Vs of the second reservoir105is equal to or greater than the threshold value Vmin when the ink cartridge50installed in the installation case71is not a fresh ink cartridge50. However, the processing in steps S52to S55may not be performed. More specifically, the controller230may temporarily cancel the empty ink state in response to the ink cartridge50installed in the installation case71. The processing in step S54may be performed without performing the processing in steps S52and S53, or may be performed with either step S52or S53.

In the first embodiment, the ink discharge through the recording head39refers to image recording on a sheet. However, the ink discharge through the recording head39may be a purge for forcibly discharging the ink through the nozzles40of the recording head39.

In the first embodiment, the controller230disables the ink discharge through the recording head39when the flag S_Empty is ON. However, the ink discharge through the recording head39may not be disabled, and the controller230may simply display the notification screen S_Empty on the display17when the flag S_Empty is ON. Similarly, the controller230disables the ink discharge through the recording head39when the non-residual ink flag is ON. However, the ink discharge through the recording head39may not be disabled, and the controller230may simply display the notification screen S_Empty on the display17when the flag S_Empty is ON. In contrast, the controller230may simply disable the ink discharge through the recording head39when the flag S_Empty is ON without displaying the notification screen S_Empty on the display17. This prevents at least air entrapment described above. Similarly, the controller230may simply disable the ink discharge through the recording head39when the non-residual ink flag is ON without displaying, on the display17, the notification screen notifying that the ink is flowing.

In the first embodiment, the controller230stores the total amount Vt into the EEPROM234after the ink cartridge50is replaced, and obtains the current total amount Vt by subtracting the ink amount equivalent to the count value TN from the total amount Vt. In some embodiments, the total amount Vt is updated and stored into the EEPROM234every time when the ink is discharged through the recording head39. When the ink discharge through the recording head39is performed subsequently, the same ink amount as the discharged amount may be calculated based on the count value TN, and subtracted from the total amount Vt stored in the EEPROM234to update the total amount Vt.

In the first embodiment, the flag C_Empty is set ON in response to the output from the liquid level sensor155changing from a low-level signal to a high-level signal, and the notification screen C_Empty appears on the display17. In some embodiments, the flag C_Empty may be set ON in response to the count value SN1reaching a predetermined threshold after the output from the liquid level sensor155changes from a low-level signal to a high-level signal, and the notification screen C_Empty may appear on the display17.

In the image recording process according to the first embodiment, the operations in steps S11to S17excluding the image recording operation, or the operations in step S18and subsequent steps, may be performed when the cover48is closed or when the power of the printer is turned on.

The value indicating OFF may be substituted into the temporary canceling flag in response to a low-level signal received from the liquid level sensor155in a step other than step S75or S83. For example, the value indicating OFF may be substituted into the temporary canceling flag in step S17in response to a low-level signal received from the liquid level sensor155.

Second Embodiment

A second embodiment will now be described. The structure of a multifunction peripheral10according to the second embodiment is the same as in the first embodiment, and will not be described in detail. The operation of the multifunction peripheral10according to the second embodiment will now be described.

Image Recording Process

The controller230performs an image recording process shown inFIG. 22in response to a recording instruction input to the multifunction peripheral10. The recording instruction is an example of a discharge instruction for causing the multifunction peripheral10to record an image represented by image data on a sheet. The recording instruction may be received in any manner, but may be received as a corresponding user operation performed through the operation panel22or may be received from an external device through a communication interface (not shown).

First, the controller230determines the set values for four flags C_Empty (S111). When determining that at least one of the four flags C_Empty is set ON (S111: ON), the controller230displays a notification screen C_Empty on the display17(S112). The notification screen C_Empty notifies the user that the ink cartridge50corresponding to the flag C_Empty set ON is in the cartridge empty state. For example, the notification screen C_Empty may include information indicating the color and the ink amounts Vc and Vs of the ink stored in the ink cartridge50in the cartridge empty state. In step S112, the controller230may display the notification screen S_Empty on the display17together with the notification screen C_Empty when determining that at least one of the four flags S_Empty is set ON. The operation of the display17in step S112is an example of a first operation.

The controller230also performs the processing in steps S113to S115for each ink cartridge50corresponding to the flag C_Empty set ON. More specifically, the processing in steps S113to S115is performed for each ink cartridge50for which the flag C_Empty is set ON, among the four ink cartridges50. The processing in steps S113to S115is common to the ink cartridges50. The processing in steps S113to S115for one ink cartridge50will be described.

First, the controller230determines whether the signal obtained from the installation sensor154has changed from a low-level signal to a high-level signal (S113). When the signal obtained from the installation sensor154remains unchanged from the low-level signal (S113: No), the controller230obtains signals output from four liquid level sensors155at the current time (S117). When the flag C_Empty is in ON state, the liquid level of the second reservoir105of the subtank100is lower than the predetermined level B. However, while the liquid level of the second reservoir105is being lowered to a position immediately above the communication port129, or in the cartridge empty state, image recording can be performed based on the recording instruction until the empty ink state is entered.

When determining that the signal obtained from the installation sensor154has changed from a low-level signal to a high-level signal (S113: Yes), the controller230repeatedly performs the processing in step S114at predetermined time intervals until the signal output from the installation sensor154changes from a high-level signal to a low-level signal again (S114: No). In other words, the controller230repeatedly performs the processing in step S114until the ink cartridge50is removed from the installation case71and an ink cartridge50is newly installed in the installation case71.

When obtaining a low-level signal after a high-level signal from the installation sensor154(S114: Yes), the controller230determines whether the flag S_Empty is ON (S115). When the flag S_Empty is ON (S115: Yes), the controller230performs the process described below (seeFIG. 26). The controller230also stores, into the EEPROM234, the time at which the low-level signal is obtained from the installation sensor154after obtaining the high-level signal. The controller230may measure the time by operating a timer after obtaining the low-level signal from the installation sensor154, instead of storing the time. The stored time or the measured time is used in an empty-state fully canceling process (described below).

When the flag S_Empty is OFF (S115: No), the controller230performs the empty-state temporary canceling process (S116). The empty-state temporary canceling process is to delete the notification screen C_Empty appearing on the display17. The empty-state temporary canceling process will be described in detail with reference toFIG. 24. Then, the steps subsequent to step S111are performed again in response to the completion of the empty-state temporary canceling process.

The controller230obtains signals output from the four liquid level sensors155at the current time when the flags C_Empty corresponding to all the ink cartridges50are all not ON, or in other words, are all OFF (S117). In step S117, the controller230further causes the RAM233to store information indicating whether the signal obtained from each liquid level sensor155is a high-level signal or a low-level signal.

The controller230then records the image represented by the image data included in the recording instruction on one sheet (S118). More specifically, the controller230causes the sheet on the feed tray20to be conveyed by the feed roller25and the conveyance roller34, the recording head39to discharge the ink, and the sheet having the recorded image to be discharged to the discharge tray21with the discharge roller36.

The controller230then obtains signals output from the four liquid level sensors155at the current time upon recording the image on one sheet in response to the recording instruction (S119). Similarly to step S117, the controller230causes the RAM233to store information indicating whether the signal obtained from the liquid level sensor155is a high-level signal or a low-level signal (S119). The controller230then performs a counting process (S120). The counting process is to update the count values TN, SN1, and SN2, the flag C_Empty, and the flag S_Empty based on the signals obtained from each liquid level sensor155in steps S117and S119. The counting process will be described in detail below with reference toFIG. 23.

The controller230then repeatedly performs the processing in steps S111to S120until all the images indicated by the recording instruction are recorded on one sheet (S121: Yes). When recording all the images indicated by the recording instruction on one sheet (S121: No), the controller230determines the set values for the four flags S_Empty and the set values for the four flags C_Empty (S122and S123).

When at least one of the four flags S_Empty is set ON (S122: ON), the controller230displays the notification screen S_Empty on the display17(S124). When all the four flags S_Empty are set OFF and at least one of the four flags C_Empty is set ON (S122: OFF and S123: ON), the controller230displays the notification screen C_Empty on the display17(S125). The processing in steps S124and S125is an example of activating the alarm.

The notification screen C_Empty displayed in step S123may be the same as in step S112. The notification screen C_Empty notifies the user that the ink cartridge50corresponding to the flag C_Empty set ON is in the cartridge empty state. For example, the notification screen C_Empty may include information indicating the color and the ink amounts Vc and Vs of the ink stored in the ink cartridge50in the cartridge empty state. In contrast, when all the four flags S_Empty and the four flags C_Empty are set OFF (S123: OFF), the controller230completes the image recording process without performing the processing in steps S124and S125.

The notification screen S_Empty notifies the user that the corresponding subtank100is in the empty ink state and the ink cannot be discharged through the recording head39. For example, the notification screen S_Empty may include information indicating the color and the ink amounts Vc and Vs of the ink stored in the subtank100in the empty ink state.

An example of the discharge instruction is not limited to the recording instruction, but may be a maintenance instruction instructing maintenance of the nozzles40such as a purge. For example, the controller230performs the same process as inFIG. 22in response to a maintenance instruction obtained through the operation panel22. The process in response to a maintenance instruction differs from the above process in the manner described below. First, the controller230drives a maintenance mechanism (not shown) in step S118, and discharges the ink through the nozzles40. The controller230also performs the processing in steps subsequent to step S21without performing the processing in step S121after the counting process.

Counting Process

The counting process performed by the controller230in step S120will be described in detail with reference toFIG. 23. The controller230performs the counting process independently for each of the four ink cartridges50. The counting process is common to the ink cartridges50. The counting process for one ink cartridge50will be described.

First, the controller230compares sets of information indicating the signals from the liquid level sensors155stored in the RAM233in steps S117and S119(S131). More specifically, the controller230determines whether the signal from each of the four liquid level sensors155has changed before and after the processing in step S118immediately before the counting process (S120).

When the sets of information stored in the RAM233in steps S117and S119both indicate a low-level signal (S131: L→L) (in other words, the output of each liquid level sensor155remains unchanged before and after the processing in step S118), the controller230updates the count value TN (S132). More specifically, the controller230counts up the count value TN to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S118.

The controller230also calculates the current total amount Vt (S133). First, the controller230calculates the total amount Vt after the cartridge replacement that is the sum of the ink amount Vc and the ink amount Vs stored in the EEPROM234after the cartridge is replaced. The controller230then calculates the current total amount Vt by subtracting the ink amount equivalent to the count value TN from the calculated total amount Vt (Vt=Vt−TN). The controller230then obtains the ink amounts Vc and Vs based on the calculated current total amount Vt and the volume Vth(S133).

The controller230then displays the obtained total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S134). Further, the controller230overwrites the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50with the obtained ink amount Vc (S135).

When the information stored in the RAM233in step S117indicates a low-level signal and the information stored in the RAM233in step S119indicates a high-level signal (S131: L→H) (in other words, the output of each liquid level sensor155is changed before and after the processing in step S118) (S136), the controller230substitutes the value indicating ON into the flag C_Empty. The output from the liquid level sensors155changing from a low-level signal to a high-level signal corresponds to the liquid level of the second reservoir105reaching the predetermined level B during the processing in step S118as shown inFIG. 19A. Subsequently, no ink transfer occurs between the ink cartridge50and the subtank100.

The controller230also reads a predetermined ink amount Vcc (=0) from the ROM232, and sets the ink amount Vc to the predetermined ink amount Vcc (S137). Similarly, the controller230reads a predetermined ink amount Vsc (equivalent to the volume of a part of the second reservoir105lower than the predetermined level B) from the ROM232, and sets the ink amount Vs to the predetermined ink amount Vsc (S137). The ink amounts Vc and Vs calculated in the residual amount updating process include errors. The controller230thus sets the ink amount Vc to the predetermined ink amount Vcc and the ink amount Vs to the predetermined ink amount Vsc at the time when the output from the liquid level sensor155changes from a low-level signal to a high-level signal, thus resetting the accumulated errors. Further, the controller230calculates the current total amount Vt as a value equal to the ink amount Vs (Vt=Vsc) (S137). When the ink amount Vc is zero, the total amount Vt has the same value as the ink amount Vs.

The controller230then displays the current total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S138). The controller230also overwrites the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50with the above ink amount Vc (S139).

The output of each liquid level sensor155changes during the processing in step S118, and thus the predetermined ink amount Vsc read in step S137is not strictly the amount of ink stored in the subtank100at the moment when the output from the liquid level sensor155changes, but indicates the amount of ink immediately before the output from the liquid level sensor155changes. With the difference between the ink amounts being small, the ink amount Vsc read in step S137is approximately the ink amount Vs at the time when the output from the liquid level sensor155changes.

The controller230also counts up the count value SN1stored in EEPROM234to the value equivalent to the amount of ink instructed to discharge in the immediately preceding step S118(S140). In other words, the controller230starts updating the count value SN1in response to the output from the liquid level sensors155changing from a low-level signal to a high-level signal. The controller230counts up the count value TN stored in the EEPROM234to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S118.

The controller230then calculates the ink amount Vs (S141). The calculated ink amount Vs is obtained by subtracting the ink amount equivalent to the count value SN1from the ink amount Vsc stored in the ROM232. As described above, after the output from the liquid level sensor155changes to a high-level signal, the ink amount Vs is the same value as the current total amount Vt. The ink amount Vc is zero.

The controller230then displays one of the current total amount Vt and the ink amount Vs on the display17(S142). The ink amount Vc is zero after the output of liquid level sensor155changes to a high-level signal, and thus the controller230does not overwrite the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50.

The controller230then compares the count value SN1updated in step S140with the threshold value Nth(S143). When determining that the count value SN1updated in step S140is smaller than the threshold value Nth(S143: No), the controller230completes the counting process. In contrast, when determining that the count value SN1updated in step S140is equal to or greater than the threshold value Nth(S143: Yes), the controller230substitutes the value indicating ON into the flag S_Empty (S144). The controller230disables the ink discharge through the recording head39in response to the flag S_Empty set ON, and completes the counting process.

When the sets of information stored in the RAM233in steps S117and S119both indicate a high-level signal (S131: H→H), the controller230determines whether the temporary canceling flag stored in the EEPROM234is ON (S145). When the temporary canceling flag is ON (S145: No), the controller230reads the count value SN1stored in the EEPROM234. The controller230then counts up the read count value SN1to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S118and stores the value into the EEPROM234again. More specifically, the controller230updates the count value SN1(S140). The controller230also updates the count value TN. The controller230then performs the processing from steps S141to S144described above using the count value SN1updated in step S140.

When the temporary canceling flag is ON (S145: Yes), the controller230performs the empty-state fully canceling process (S146). The empty-state fully canceling process will be described in detail below with reference toFIG. 25.

Empty-State Temporary Canceling Process

With reference toFIG. 24, the empty-state temporary canceling process performed by the controller230in step S116will be described in detail. The controller230performs the empty-state temporary canceling process independently for each of the four ink cartridges50. The empty-state temporary canceling process is common to the ink cartridges50. The empty-state temporary canceling process for one ink cartridge50will be described.

In the counting process, when determining that the signal of the liquid level sensor155changes from a low-level signal to a high-level signal (S131: L→H), the controller230substitutes the value indicating ON into the flag C_Empty (S136). In the image recording process, when determining that the flag C_Empty is set ON (S111: ON), the controller230displays the notification screen C_Empty on the display17(S112).

In the above state (or the state of the controller230displaying the notification screen C_Empty on the display17), the ink cartridge50is in the state of no ink flowing toward the subtank100, or in the state of the ink amount Vc being zero (Vc=0). Also, the liquid level of the ink in the subtank100is lower than the predetermined level B. The user is thus to replace the empty ink cartridge50with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink before the empty ink state shown inFIG. 19Bis entered.

In the process of replacing the ink cartridge50by the user, the controller230obtains a low-level signal from the installation sensor154, then obtains a high-level signal from the installation sensor154, and further obtains a low-level signal from the installation sensor154(S114: Yes). More specifically, in the process of removing the ink cartridge50from the installation case71, the controller230obtains a low-level signal from the installation sensor154and then obtains a high-level signal from the installation sensor154. In the subsequent process of inserting the ink cartridge50into the installation case71, the controller obtains a high-level signal from the installation sensor154and then obtains a low-level signal from the installation sensor154.

In the empty-state temporary canceling process, the controller230reads CTG information from the memory of the IC chip66through the contact152and stores the read CTG information into the EEPROM234(S151). When the ink cartridge50is replaced with a fresh ink cartridge50, an initial ink amount Vc0is read as the ink amount Vc from the memory of the IC chip66. The identification information is also read from the memory of the IC chip66.

When determining that the initial ink amount Vc0is read (S152: Yes), the controller230does not perform the processing in step S153(described later) and performs the processing in step S154(described later). When determining that the initial ink amount Vc0is not read (S152: No), the controller230performs the processing in step S153(described later). When the initial ink amount Vc0is not read, the ink amount Vc read from the memory of the IC chip66is not the initial ink amount Vc0but is a value smaller than the initial ink amount Vc0.

The controller230compares a total amount Vt obtained by adding the ink amount Vc read from the memory of the IC chip66to the ink amount Vs read from the EEPROM234with the threshold value Vmin (S153). The threshold value Vmin is equivalent to the total amount when the liquid level reaches the predetermined level B in the second reservoir105of the subtank100. When the calculated total amount Vt is equal to or greater than the threshold value Vmin (S153: Yes), the ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100, and the liquid level of the ink in the second reservoir105reaches the predetermined level B or higher. In contrast, when the calculated total amount Vt is smaller than the threshold value Vmin (S153: No), the controller230completes the empty-state temporary canceling process.

When the calculated total amount Vt is smaller than the threshold value Vmin, the liquid level of the ink in the second reservoir105does not reach the predetermined level B or higher despite any ink transfer from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100. Thus, the controller230maintains the state of the notification screen C_Empty appearing on the display17.

When determining that the calculated total amount Vt is equal to or greater than the threshold value Vmin (S153: Yes), the controller230compares the identification information read from the memory of the IC chip66with the identification information read from the memory of the IC chip66of the ink cartridge50yet to be replaced (S154). The identification information read from the memory of the IC chip66of the ink cartridge50yet to be replaced is stored in the EEPROM234. For example, with the ink cartridge50replaced with a fresh ink cartridge50, the compared two sets of identification information disagree with each other. The identification information is, for example, the serial number of the ink cartridge50.

When determining that the compared two sets of identification information agree with each other (S154: No), the controller230completes the empty-state temporary canceling process. When the ink cartridge50having the ink used up to have the ink amount Vc of zero in the first reservoir53is installed in the installation case71again, no ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100, and thus the empty state C_Empty is not to be canceled temporarily.

When determining that the compared two sets of identification information disagree with each other (S154: Yes), the controller230stores the count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the EEPROM234into another storage area of the EEPROM234(S155). The count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the other storage area of the EEPROM234are used when C_Empty is not fully canceled after the empty state C_Empty is temporarily canceled as described later.

The controller230calculates the total amount Vt after the cartridge replacement (S156). In detail, the controller230calculates the ink amount Vs before the cartridge replacement (equal to the total amount Vt) based on the count value SN1before the cartridge replacement stored in the EEPROM234and the ink amount Vsc stored in the ROM232, and stores the ink amount into the EEPROM234. Based on the calculated ink amount Vs and the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50, the total amount Vt after the cartridge replacement is calculated. More specifically, the ink amount Vc stored in the first reservoir53of the fresh ink cartridge50is added to the ink amount Vs stored in the second reservoir105of the subtank100immediately before the ink cartridge50is replaced. The controller230thus calculates the sum of the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50and the ink amount Vs before the cartridge replacement stored in the EEPROM234as the total amount Vt (Vt=Vs+Vc).

The controller230calculates the ink amount Vc and the ink amount Vs obtained when ink transfer from the first reservoir53to the second reservoir105is complete based on the calculated total amount Vt and the volume Vthread from the EEPROM234(S156). When the ink cartridge50is replaced, the ink stored in the first reservoir53of the newly installed ink cartridge50flows into the second reservoir105of the subtank100through the liquid flow path103. As a result, the ink amount Vc of the first reservoir53decreases, and the ink amount Vs of the second reservoir105increases. The liquid level of the ink in the second reservoir105of the subtank100then reaches the imaginary line L, and the equilibrium state is entered.

The controller230resets the count values TN and SN1stored in the EEPROM234after performing the processing in step S156(S157). This sets the count values TN and SN1to their initial values (zero).

The controller230displays the obtained total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S158). The controller230stores the calculated ink amount Vc into the memory of the IC chip66through the contact152(S159). When the initial ink amount Vc0is stored in the memory of the IC chip66, the controller230overwrites the initial ink amount Vc0with the calculated ink amount Vc (an example of a second value). With the ink amount Vc0overwritten with another ink amount Vc in the memory of the IC chip66, the ink cartridge50is determined not to be a fresh ink cartridge. In the manufacturing processes, a flag indicating that the ink cartridge50is a fresh ink cartridge may be set ON in the memory of the IC chip66. Once the ink cartridge50is installed in the installation case71, the controller230may substitute the value indicating OFF into the flag. The controller230can thus determine whether the ink cartridge50is a fresh ink cartridge based on the value of the flag.

The controller230substitutes the value indicating OFF into the flag C_Empty (S160). The controller230substitutes the value indicating ON into the temporary canceling flag (S161). The controller230deletes the notification screen C_Empty from the display17(S162), and completes the empty-state temporary canceling process.

Empty-State Fully Canceling Process

With reference toFIG. 25, the empty-state fully canceling process performed by the controller230in step S146will be described in detail. The controller230performs the empty-state fully canceling process independently for each of the four ink cartridges50. The empty-state fully canceling process is common to the ink cartridges50. The empty-state canceling process for one ink cartridge50will be described.

When determining that the temporary canceling flag is ON in the counting process (S145: Yes), the controller230performs the empty-state fully canceling process. At this time, the flag C_Empty is OFF, and the notification screen C_Empty is not on the display17.

As shown inFIG. 20, when the temporary canceling flag is ON, the ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100, and the liquid level of the ink in the second reservoir105is lower than the predetermined level B. When the processing in step S118is performed in this state, the controller230counts up the count value SN2stored in the EEPROM234to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S118(S170). In other words, the controller230starts updating the count value SN2in response to the temporary canceling flag set ON. The controller230counts up the count value TN stored in the EEPROM234to a value equivalent to the amount of ink instructed to discharge in the immediately preceding step S118.

The controller230then calculates the current total amount Vt (S171). The current total amount Vt is obtained by subtracting the ink amount equivalent to the count value TN from the sum of the ink amount Vc and the ink amount Vs stored in the EEPROM234. The controller230obtains the ink amounts Vc and Vs based on the calculated current total amount Vt and the volume Vth(S171).

The controller230then displays the obtained total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S172). Further, the controller230overwrites the ink amount Vc stored in the memory of the IC chip66of the ink cartridge50with the obtained ink amount Vc (S173).

The controller230then determines whether the output from the liquid level sensor155is a low-level signal (S174). When determining that the output from the liquid level sensor155is a low-level signal (S174: Yes), the controller230substitutes the value indicating OFF into each of the temporary canceling flag and the flag S_Empty (S175and S176).

When determining that the output from the liquid level sensor155is not a low-level signal but is a high-level signal (S174: No), the controller230compares the sum of the count value SN2updated in step S170and the count value SN1stored in the other area of the EEPROM234with the threshold value Nth(S177). The sum of the count value SN2and the count value SN1is an example of a third count value.

When determining that the sum of the count value SN2and the count value SN1updated in step S170is smaller than the threshold value Nth(S177: No), the controller230determines whether a wait time Tw has elapsed from the time stored in the EEPROM234in the image recording process (the time when the low-level signal is obtained after the high-level signal is obtained from the installation sensor) (S178). The wait time Tw is set by a wait time Tw setting process described later. The wait time Tw is an example of a first elapsed time.

When determining that the wait time Tw has not elapsed from the time stored in the EEPROM234(S178: No), the controller230completes the empty-state fully canceling process.

When determining that the wait time Tw has elapsed from the time stored in the EEPROM234(S178: Yes), the controller230substitutes the value indicating ON into the flag C_Empty (S179). The controller230then displays the notification screen C_Empty on the display17in response to the flag C_Empty set ON (S180).

In the empty-state temporary canceling state, the total amount Vt that is the sum of the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50and the ink amount Vs of the second reservoir105of the subtank100is equal to or greater than the threshold value Vmin. However, when the ink amount Vc stored in the memory of the IC chip66is larger than the amount of ink substantially stored in the ink cartridge50or the ink transfer from the ink cartridge50to the subtank100is disabled, the liquid level of the ink is not raised to the predetermined level B in the second reservoir105of the subtank100. In this case, the user may be urged to replace the ink cartridge50again with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink, and the ink discharge through the recording head39is to be disabled until the ink cartridge50is replaced again.

The controller230reads the count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the other area of the EEPROM234(S181) and updates the count values TN and SN1, the ink amount Vc, and the ink amount Vs currently stored in the EEPROM234to the read values (S182). More specifically, the count value SN2is added to each of the count values TN and SN1stored in the other area of the EEPROM234, and the count values TN and SN1stored in the EEPROM234are updated to the resultant values. In addition, the controller updates the ink amount Vs by subtracting the value equivalent to the updated count value SN1from the Vsc stored in the ROM232. The controller230updates the ink amount Vc to zero. Further, the controller230substitutes the value indicating OFF into the temporary canceling flag (S183), and completes the empty-state fully canceling process. This ends the empty-state temporary canceling state, and the empty ink state is entered. The updated count value SN1corresponds to a third count value.

When determining that the sum of the count value SN2and the count value SN1updated in step S170is equal to or greater than the threshold value Nth, (S177: Yes), the controller230substitutes the value indicating ON into the flag S_Empty (S184). The sum of the count value SN2and the count value SN1equal to or greater than the threshold value Nthindicates that the liquid level of the ink in the second reservoir105of the subtank100has reached the position immediately above the communication port129.

The controller230displays a screen for notifying that the ink is flowing into the subtank100from the ink cartridge50on the display17(S185). The controller230determines whether the wait time Tw has elapsed from the time stored in the EEPROM234(S186). When determining that the wait time Tw has not elapsed from the time stored in the EEPROM234(S186: No), the controller230continuously displays the above screen on the display17. More specifically, until the wait time Tw elapses from the time stored in the EEPROM234, image recording performed in the next step S118is suspended. The operation performed by the display17in step S186is an example of a second operation.

When determining that the wait time Tw has elapsed from the time stored in the EEPROM234(S186: Yes), the controller230determines whether the signal output from the liquid level sensor155is a low-level signal (S187). When determining that the signal output from the liquid level sensor155is a low-level signal (S187: Yes), the controller230performs the processing from steps S175to S176described above, and completes the empty-state fully canceling process. The signal output from the liquid level sensor155being the low-level signal indicates that the ink is transferred from the ink cartridge50to the subtank100, and the liquid level of the ink in the second reservoir105reaches the predetermined level B before the wait time Tw elapses from the time stored in the EEPROM234. This ends the empty-state temporary canceling state. In the next step S118, the suspended image recording is resumed. The controller230may continue to determine whether the signal output from the liquid level sensor155is a low-level signal until the wait time Tw elapses, instead of determining whether the signal output from the liquid level sensor155is a low-level signal after the wait time Tw elapses from the time stored in the EEPROM234.

In contrast, when determining that the signal output from the liquid level sensor155is not a low-level signal but is a high-level signal (S187: No), the controller230displays the notification screen S_Empty instead of an in-flow notification screen on the display17(S188). Then, the processing in steps S181to S183described above is performed, and the empty-state fully canceling process is complete. This ends the empty-state temporary canceling state, and the empty ink state is entered.

When determining that the flag S_Empty is ON in step S115in the image recording process (S115: Yes), the controller230performs the process shown inFIG. 26. As described above, when the ink amount Vc stored in the memory of the IC chip66is larger than the amount of ink substantially stored in the ink cartridge50or the ink transfer from the ink cartridge50to the subtank100is disabled, the liquid level of the ink in the second reservoir105of the subtank100is not raised to the predetermined level B. In this case, the ink cartridge50is to be replaced again with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink.

However, in the state of the flag S_Empty being ON, the sum of the count value SN2and the count value SN1updated in step S170is already equal to or greater than the threshold value Nth. Thus, although the ink cartridge50is replaced again, image recording performed in the empty-state temporary canceling state may cause air entrapment described above. When determining that the flag S_Empty is ON (S115: Yes), the controller230does not perform the empty-state temporary canceling process.

As shown inFIG. 26, when determining that the flag S_Empty is ON (S115: Yes), the controller230displays the screen notifying that the ink is flowing into the subtank100from the ink cartridge50on the display17(S190).

The controller230determines whether the signal output from the liquid level sensor155is a low-level signal (S191). When determining that the signal output from the liquid level sensor155is not a low-level signal but is a high-level signal (S191: No), the controller230repeatedly performs the processing in step S191until the signal output from the liquid level sensor155changes to a low-level signal.

When determining that the signal output from the liquid level sensor155is a low-level signal (S191: Yes), the controller230calculates the ink amount Vs before the cartridge replacement (equal to the total amount Vt) based on the count value SN before the cartridge replacement stored in the EEPROM234and the ink amount Vsc stored in the ROM232, and stores the calculated value into the EEPROM234. Based on the calculated ink amount Vs and the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50, the total amount Vt after the cartridge replacement is calculated (S192: Vt=Vs+Vc).

The controller230calculates the ink amount Vc and the ink amount Vs when ink transfer from the first reservoir53to the second reservoir105is complete based on the calculated total amount Vt and the volume Vthread from the EEPROM234(S192).

The controller230resets the count values TN, SN1, and SN2stored in the EEPROM234(S193). This sets the count values TN, SN1, and SN2to their initial values (zero).

The controller230displays the obtained total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S194). The controller230stores the calculated ink amount Vc into the memory of the IC chip66through the contact152(S195).

The controller230substitutes the value indicating OFF into each of the flag S_Empty and the flag C_Empty (S196and S197). The controller230deletes the in-flow notification screen from the display17(S198) and returns to the processing in step S117in response to the flag S_Empty set OFF.

Wait Time Tw Setting Process

With reference toFIG. 27, the wait time Tw setting process performed by the controller230will be described in detail. The controller230performs the wait time Tw setting process independently for each of the four ink cartridges50. The wait time Tw setting process is common to the ink cartridges50. The wait time Tw setting process for one ink cartridge50will be described.

The controller230performs the wait time Tw setting process when the ink cartridge50is installed firstly in the installation case71of the multifunction peripheral10. The controller230determines whether the ink cartridge50is installed firstly in the installation case71based on, for example, identification information read from the IC chip66of the installed ink cartridge50indicating that the cartridge has been packaged with the multifunction peripheral10, or a flag indicating an initial ink loading operation not stored in the EEPROM234. The determination causes the time to be measured from when the ink flows into the second reservoir105of the subtank100in the empty state to when the liquid level of the ink reaches the predetermined level B.

As shown inFIG. 27, the controller230stores, into the EEPROM234, the time when the ink cartridge50is installed firstly in the installation case71, or in other words, the time when a high-level signal is obtained from the installation sensor154and then a low-level signal is further obtained from the installation sensor154. The controller230then calculates, in response to the signal received from the liquid level sensor155changing from a high level to a low level, a time T0 from the time stored in the EEPROM234to when the signal from the liquid level sensor155changes (S201). The time T0 is an example of a second elapsed time.

When a fresh ink cartridge50is installed in the installation case71, the ink flows from the first reservoir53into the second reservoir105. The liquid level of the ink in the second reservoir105then reaches the predetermined level B over time, and thus the liquid level sensor155outputs a low-level signal.

Subsequently, the controller230calculates a difference between the calculated time T0 and the design value Ts prestored in the EEPROM234(|Ts−T0|), and determines whether the calculated difference is within the threshold value range X (S202: X≥|Ts−T0|). When the calculated difference is within the threshold value range X (S202: Yes), the controller230stores, into the EEPROM234, the time T0 or the time obtained by adding or subtracting a predetermined time to or from the time T0 as the wait time Tw (S203). When the calculated difference is out of the threshold value range X (S202: No), the controller230stores, into the EEPROM234, the design value Ts or the time obtained by adding or subtracting a predetermined time to or from the design value Ts as the wait time Tw (S204).

Operational Effects of Second Embodiment

The structure according to the second embodiment can delete the notification screen C_Empty from the display17in the cartridge empty state of the notification screen C_Empty appearing on the display17after the ink cartridge50is replaced and before the liquid level sensor155outputs a low-level signal. When the elapsed time from the replacement of the ink cartridge50reaches the wait time Tw after the notification screen C_Empty is deleted from the display17, the notification screen C_Empty appears on the display17. Thus, if the liquid level of the ink in the second reservoir105of the subtank100is not equal to or higher than the predetermined level B after the ink cartridge50is replaced, the user can be urged to replace the ink cartridge50again through the notification.

Further, when the ink cartridge50installed in the installation case71does not store an amount of ink in the first reservoir53sufficient to cause the liquid level of the ink in the second reservoir105of the subtank100to reach the predetermined level B or higher, the notification screen C_Empty is not deleted from the display17.

The wait time Tw is set in accordance with the time T0 from when the ink flows from the first reservoir53of the ink cartridge50installed firstly in the installation case71to the second reservoir105of the subtank100to when the controller230receives a low-level signal from the liquid level sensor155, and thus can be set in accordance with differences between individual devices.

When the elapsed time from the replacement of the ink cartridge50reaches the wait time Tw and the notification screen C_Empty appears on the display17after the notification screen C_Empty is deleted from the display17, the count value SN1used before the notification screen C_Empty is deleted from the display17is added to the count value SN2and updated after the notification screen C_Empty appears on the display17.

When the sum of the count value SN2and the count value SN1reaches the threshold value Nthafter the cartridge empty state is canceled, the image recording is suspended and thus the controller230can regulate the amount of ink discharged through the recording head39before receiving a low-level signal from the liquid level sensor155. This prevents air from the second reservoir105from entering the recording head39. Thereafter, when a low-level signal is received from the liquid level sensor155, the image recording is resumed.

When the image recording is suspended, a screen notifying that the ink is flowing into the subtank100from the ink cartridge50appears on the display17. The user can thus be notified whether to replace the ink cartridge50or to wait.

When the ink cartridge50installed in the installation case71again has the ink in the first reservoir53used up and needs replacement, the notification screen C_Empty is not deleted from the display17.

When the temporary canceling state is entered or the temporary canceling flag is ON, the controller230substitutes the value indicating OFF into the temporary canceling flag in response to a low-level signal from the liquid level sensor155. Thus, when the liquid level of the second reservoir105is substantially equal to or higher than the predetermined level B after the cartridge is replaced, the temporary canceling state is canceled. The controller also substitutes the value indicating OFF into the non-residual ink flag as well when the liquid level of the second reservoir105is substantially equal to or higher than the predetermined level B after the cartridge is replaced. This prevents air entrapment described above.

Modifications of Second Embodiment

The empty-state temporary canceling process in the second embodiment includes the determination (S152) as to whether the ink cartridge50installed in the installation case71stores the initial ink amount Vc0, or in other words, as to whether the ink cartridge50is a fresh ink cartridge50, or the determination (S153) as to whether the total amount Vt that is the sum of the ink amount Vc of the first reservoir53and the ink amount Vs of the second reservoir105is equal to or greater than the threshold value Vmin when the ink cartridge50installed in the installation case71is not a fresh ink cartridge. However, the processing in steps S152to S155may not be performed. More specifically, the controller230may temporarily cancel the empty ink state in response to the ink cartridge50installed in the installation case71. Either the processing in step S152or S153may be performed selectively. The processing in step S154may be performed without performing the processing in steps S152and S153, or may be performed with either step S152or S153.

In the second embodiment, the flag C_Empty is set ON in response to the output from the liquid level sensor155changing from a low-level signal to a high-level signal, and the notification screen C_Empty appears on the display17. In some embodiments, the flag C_Empty may be set ON in response to the count value SN1reaching a predetermined threshold after the output from the liquid level sensor155changes from a low-level signal to a high-level signal, and the notification screen C_Empty may appear on the display17.

In the second embodiment, the cartridge empty state is temporarily canceled when the ink cartridge50is replaced and then a low-level signal is received from the installation sensor154. However, the empty ink state, instead of the cartridge empty state, may be temporarily canceled in response to a low-level signal received from the installation sensor154. More specifically, when the flag S_Empty is ON, the controller230performs the empty-state temporary canceling process in response to a low-level signal received from the installation sensor154, and substitutes the value indicating OFF into the flag S_Empty. Through this process, the notification screen S_Empty is deleted from the display17after the cartridge is replaced and before the liquid level sensor155outputs a low-level signal.

When the flag S_Empty is ON, the controller230may set the flag S_Empty OFF and delete the notification screen S_Empty from the display17in response to a low-level signal from the installation sensor154, or by determining that the ink cartridge50installed in the installation case71stores the initial ink amount Vc0or that the total amount Vt that is the sum of the ink amount Vc of the first reservoir53and the ink amount Vs of the second reservoir105is equal to or greater than the threshold value Vmin although the ink cartridge50installed in the installation case71is not a fresh ink cartridge. When the flag S_Empty is ON, the controller230may not provide a notification but may disable ink discharge. When the flag S_Empty is OFF, the controller may enable the ink discharge. Further, the controller230may both provide a notification and disable ink discharge.

In the second embodiment, the controller230stores the total amount Vt after replacement of the ink cartridge50into the EEPROM234, and obtains the current total amount Vt by subtracting the ink amount equivalent to the count value TN from the total amount Vt. In some embodiments, the total amount Vt is updated and stored into the EEPROM234every time when the ink is discharged through the recording head39. When the ink discharge through the recording head39is performed subsequently, the same ink amount as the discharged amount may be calculated based on the count value TN, and subtracted from the total amount Vt stored in the EEPROM234to update the total amount Vt.

In the second embodiment, the ink discharge through the recording head39refers to image recording on a sheet. However, the ink discharge through the recording head39may be a purge for forcibly discharging the ink through the nozzles40of the recording head39.

In the image recording process according to the second embodiment, the operations in steps S111to S117excluding the image recording operation, or the operations in step S118and subsequent steps, may be performed when the cover48is closed or when the power of the printer is turned on.

The value indicating OFF may be substituted into the temporary canceling flag in response to a low-level signal received from the liquid level sensor155in a step other than step S175or S183. For example, the value indicating OFF may be substituted into the temporary canceling flag in step S117in response to a low-level signal received from the liquid level sensor155.

Third Embodiment

A third embodiment will now be described. The structure of a multifunction peripheral10according to the third embodiment is the same as in the first embodiment, and will not be described in detail. Additionally, an image recording process (FIGS. 14 and 18), a counting process (FIG. 15), and an empty-state fully canceling process (FIG. 17) in the operation of the multifunction peripheral10are also the same as in the first embodiment. The empty-state temporary canceling process according to the third embodiment will now be described.

Empty-State Temporary Canceling Process

With reference toFIG. 28, the empty-state temporary canceling process performed by the controller230in step S16will be described in detail. The controller230performs the empty-state temporary canceling process independently for each of the four ink cartridges50. The empty-state temporary canceling process is common to the ink cartridges50. The empty-state temporary canceling process for one ink cartridge50will be described.

In the counting process, when determining that the count value SN1is equal to or greater than the threshold value Nth1(S43: Yes), the controller230substitutes the value indicating ON into the flag S_Empty (S44) and disables the ink discharge through the recording head39. In the image recording process, when determining that the flag S_Empty is set ON (S11: ON), the controller230displays the notification screen S_Empty on the display17(S12).

In the above state (or the state of the controller230disabling the ink discharge through the recording head39and displaying the notification screen S_Empty on the display17), as shown inFIG. 19B, the ink cartridge50is in the state of no ink flowing toward the subtank100, or in the state of the ink amount Vc being zero (Vc=0). Also, the liquid level of the ink in the subtank100is lower than the predetermined level B and reaches the position near the upper end of the communication port129. Image recording cannot be performed unless the ink discharge through the recording head39is enabled by the user replacing the ink cartridge50in the empty state with a fresh ink cartridge50or with an ink cartridge50storing a sufficient amount of ink.

In the process of replacing the ink cartridge50by the user, the controller230obtains a low-level signal from the installation sensor154, and then obtains a high-level signal from the installation sensor154, and further obtains a low-level signal from the installation sensor154(S14: Yes). More specifically, in the process of removing the ink cartridge50from the installation case71, the controller230obtains a low-level signal from the installation sensor154and then obtains a high-level signal from the installation sensor154. In the subsequent process of inserting the ink cartridge50into the installation case71, the controller230obtains a high-level signal from the installation sensor154and then obtains a low-level signal from the installation sensor154.

In the empty-state temporary canceling process, the controller230reads CTG information from the memory of the IC chip66through the contact152and stores the read CTG information into the EEPROM234(S251). When the ink cartridge50is replaced with a fresh ink cartridge50, an initial ink amount Vc0is read from the memory of the IC chip66as the ink amount Vc. The identification information is also read from the memory of the IC chip66.

The controller230then compares the ink amount Vc (here, Vc0) read from the memory of the IC chip66with the threshold value Vmin (S252). The threshold value Vmin is equivalent to the volume of a part of the second reservoir105between the position near the upper end of the communication port129and the predetermined level B. When the replaced ink cartridge50stores the amount of ink equal to or greater than the threshold value Vmin in the first reservoir53, the ink is transferred from the first reservoir53of the ink cartridge50to the second reservoir105of the subtank100, and thus the liquid level of the ink in the second reservoir105reaches the predetermined level B or higher. The cartridge is replaced with a fresh ink cartridge50, and thus the ink amount Vc is the initial ink amount Vc0equal to or greater than the threshold value Vmin.

When determining that the ink amount Vc read from the memory of the IC chip66is equal to or greater than threshold value Vmin (S252: Yes), the controller230compares the identification information read from the memory of the IC chip66with the identification information read from the memory of the IC chip66of the ink cartridge50yet to be replaced (S253). In the present embodiment, the identification information is the serial number of the ink cartridge50. The identification information read from the memory of the IC chip66of the ink cartridge50yet to be replaced is stored in the EEPROM234. In this case, with the cartridge replaced with a fresh ink cartridge50, the compared two sets of identification information disagree with each other.

When determining that the ink amount Vc read from the memory of the IC chip66is smaller than threshold value Vmin (S252: No), the controller230completes the empty-state temporary canceling process. When the ink amount Vc read from the memory of the IC chip66is smaller than the threshold value Vmin, the liquid level of the ink in the second reservoir105does not reach the predetermined level B or higher despite any ink transfer from the first reservoir53of the replaced ink cartridge50to the second reservoir105of the subtank100, and thus the empty state Empty is not to be canceled temporarily.

When determining that the compared two sets of identification information disagree with each other (S253: Yes), the controller230stores the count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the EEPROM234into another storage area of the EEPROM234(S254). The count values TN and SN1, the ink amount Vc, and the ink amount Vs stored in the other storage area of the EEPROM234are used when the empty state is not fully canceled after the empty state Empty is temporarily canceled as described later.

When determining that the compared two sets of identification information do not disagree with each other, or in other words, the two sets of information agree with each other (S253: No), the controller230completes the empty-state temporary canceling process. If the ink cartridge50remains the same before and after the replacement, ink is not transferred from the first reservoir53to the second reservoir105of the subtank100, and thus the empty state is not to be canceled temporarily.

The controller230calculates the total amount Vt after the cartridge replacement (S255). In detail, the controller230calculates the ink amount Vs before the cartridge replacement (equal to the total amount Vt) based on the count value SN before the cartridge replacement stored in the EEPROM234and an ink amount Vsc stored in the ROM232, and stores the ink amount into the EEPROM234. Based on the calculated ink amount Vs and the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50, the total amount Vt after the cartridge replacement is calculated. More specifically, the ink amount Vc stored in the first reservoir53of the newly installed ink cartridge50is added to the ink amount Vs stored in the second reservoir105of the subtank100immediately before the ink cartridge50is replaced. The controller230thus calculates the sum of the ink amount Vc read from the memory of the IC chip66of the replaced ink cartridge50and the ink amount Vs before the cartridge replacement stored in the EEPROM234as the total amount Vt (Vt=Vs+Vc).

The controller230calculates the ink amount Vc and the ink amount Vs when ink transfer from the first reservoir53to the second reservoir105is complete based on the calculated total amount Vt and the function F read from the EEPROM234(S255). When the ink cartridge50is replaced, the ink stored in the first reservoir53of the newly installed ink cartridge50flows into the second reservoir105of the subtank100through the liquid flow path103. As a result, the ink amount Vc of the first reservoir53decreases, and the ink amount Vs of the second reservoir105increases. The liquid level of the ink in the second reservoir105of the subtank100then reaches the imaginary line L, and the equilibrium state is entered.

The controller230resets the count values TN and SN1stored in the EEPROM234after performing the processing in step S254(S256). This sets the count values TN and SN1to their initial values (zero).

The controller230then displays the obtained total amount Vt and one of the ink amount Vc and the ink amount Vs on the display17(S257). The controller230stores the calculated ink amount Vc into the memory of the IC chip66through the contact152(S258).

The controller230substitutes the value indicating OFF into each of the flag S_Empty and the flag C_Empty (S259). The controller230substitutes the value indicating ON into the temporary canceling flag (S260). The controller230enables the ink discharge through the recording head39when all the four flags S_Empty are set OFF. The controller230deletes the notification screen S_Empty and the notification screen C_Empty from the display17(S261), and completes the empty-state temporary canceling process.

Operational Effects of Third Embodiment

The structure according to the third embodiment can delete the notification screen S_Empty from the display17to enable the image recording after the ink cartridge50is replaced and before the liquid level of the ink stored in the second reservoir105of the subtank100reaches the predetermined level B or higher. Thus, the multifunction peripheral10can start image recording without the user waiting after replacement of the ink cartridge50. Image recording remains enabled after replacement of the ink cartridge50without the user waiting, and thus without causing the user to worry about failures of the multifunction peripheral10or inconvenience after replacement of the main tank.

When the count value SN2reaches equal to or greater than the threshold value Nth2in the image recording performed after the notification screen S_Empty is deleted, the notification screen S_Empty appears on the display17again, and the image recording is disabled.

If the ink amount Vc stored in the replaced ink cartridge50is small, the flow rate of the ink to the subtank100from the ink cartridge50is small. In this case, the time taken by the ink transferred from the ink cartridge50to the subtank100for the liquid level of the second reservoir105to reach the predetermined level B or higher is relatively long. If image recording with a large amount of ink discharge through the recording head39is performed during this period of time, air can enter the recording head39. However, when the wait time Tw elapses after the empty-state temporary canceling state is entered, the notification screen S_Empty appears on the display17again, disabling the image recording and preventing air from entering the recording head39.

In the empty-state temporary canceling state, the image recording suspended before the liquid level sensor155outputs a low-level signal is resumed after the liquid level sensor155outputs a low-level signal.

In the state of the non-residual amount flag being ON, the controller230ends the empty-state temporary canceling state after entering the empty-state temporary canceling state to enter the empty ink state immediately before temporarily canceling the empty state Empty. This prevents air from entering the recording head39.

While waiting for the wait time Tw to elapse, the controller230displays a screen notifying that the ink is flowing into the subtank100from the ink cartridge50on the display17. The user can be notified to wait without replacing the cartridge again.

Modification 1 of Third Embodiment

In the third embodiment, the ink discharge through the recording head39refers to image recording on a sheet. However, the ink discharge through the recording head39may be a purge for forcibly discharging the ink through the nozzles40of the recording head39.

For example, the controller230can perform a large amount of purge for discharging a large amount (an example of a second amount) of ink through the nozzles40of the recording head39, and a small amount of purge for discharging a small amount (an example of a first amount) of ink. The multifunction peripheral10has such two different purge modes. A user's input or a maintenance program causes the controller230to selectively use one of the two purge modes.

As shown inFIG. 29, in a state other than the empty-state temporary canceling state, in other words, in the state of the temporary canceling flag being OFF (S300: No), the controller230performs a purge in accordance with an input (S301).

In contrast, in the empty-state temporary canceling state, in other words, in the state of the temporary canceling flag being ON (S300: Yes), the controller230determines whether the input indicates a large amount of purge (S302). When the input does not indicate a large amount of purge (S302: No), the controller230performs a purge, more specifically, a small amount of purge, in accordance with the input (S301). When the input indicates a large amount of purge (S302: Yes), the controller230displays a screen for prompting re-input on the display17(S303). Thus, in the empty-state temporary canceling state, the controller230rejects an instruction for a large amount of purge (an example of a second instruction), but accepts only an instruction for a small amount of purge (an example of a first instruction).

When receiving an instruction for a large amount of purge in the empty-state temporary canceling state, the controller230may perform a small amount of purge instead of a large amount of purge. In addition to the image recording or the purge, the ink may be discharged through the recording head39by flushing in which ink droplets are continuously discharged from all the nozzles40of the recording head39.

Modification 2 of Third Embodiment

Although the subtank100includes the liquid level sensor155in the above embodiments, the liquid level sensor155may be eliminated. The structure without the liquid level sensor155does not use the first count value SN1, which starts counting up in response to a high-level signal output from the liquid level sensor155. The controller230determines the empty ink state using the count value TN instead of the count value SN1.

More specifically, the controller230does not perform the processing in step S31in the counting process, and does not perform the processing in steps S36to S46. Instead of these steps, the controller230performs the processing in steps S32to S35when the temporary canceling flag is OFF, and substitutes the value indicating ON into the flag S_Empty when the count value TN (an example of a first count value) reaches a threshold (an example of a first threshold). This causes the notification screen S_Empty to appear on the display17, disabling the ink discharge through the recording head39. The controller230performs the empty-state fully canceling process (S46) when the temporary canceling flag is ON.

The controller230then performs the empty-state temporarily canceling process as described above. In the empty-state fully canceling process, the controller230does not perform the processing in steps S74and S88that is based on a signal output from the liquid level sensor155.

Other Modifications of Third Embodiment

In the third embodiment, the controller230disables the ink discharge through the recording head39when the flag S_Empty is ON. However, the ink discharge through the recording head39may not be disabled, and the controller230may simply display the notification screen S_Empty on the display17when the flag S_Empty is ON. Similarly, the controller230disables the ink discharge through the recording head39when the non-residual ink flag is ON. However, the ink discharge through the recording head39may not be disabled, and the controller230may simply display the notification screen S_Empty on the display17when the flag S_Empty is ON. In contrast, the controller230may simply disable the ink discharge through the recording head39when the flag S_Empty is ON without displaying the notification screen S_Empty on the display17. This prevents at least air entrapment described above. Similarly, the controller230may simply disable the ink discharge through the recording head39when the non-residual ink flag is ON without displaying the in-flow notification screen on the display17.

The controller230substitutes the value indicating ON into the flag C_Empty when the signal received from the liquid level sensor155changes from a low level to a high level. In some embodiments, the controller230may substitute the value indicating ON into the flag C_Empty when the signal received from the liquid level sensor155changes from a low-level signal to a high-level signal, and the count value SN1reaches the predetermined threshold.

In the third embodiment, the controller230stores the total amount Vt after replacement of the ink cartridge50into the EEPROM234, and obtains the current total amount Vt by subtracting the ink amount equivalent to the count value TN from the total amount Vt. In some embodiments, the total amount Vt is updated and stored into the EEPROM234every time when the ink is discharged through the recording head39. When the ink discharge through the recording head39is performed subsequently, the same ink amount as the discharged amount may be calculated based on the count value TN, and subtracted from the total amount Vt stored in the EEPROM234to update the total amount Vt.

In the image recording process according to the third embodiment, the operations in steps S11to S17excluding the image recording operation, or the operations in step S18and subsequent steps, may be performed when the cover48is closed or when the power of the printer is turned on.

Modifications of Each Embodiment

In the above embodiments, the liquid level sensor155optically detects the liquid level of the ink in the second reservoir105using a prism with different reflectance values depending on whether the ink is in contact with the rear wall112of the second reservoir105. However, the liquid level sensor155may have any structure to detect the liquid level of the ink in the second reservoir105. For example, the second reservoir105may contain an actuator that rotates depending on whether the liquid level in the second reservoir105is lower than a boundary position B, and the liquid level sensor155may detect a detection target portion included in the actuator located at a detection position. In some embodiments, the liquid level of the ink in the second reservoir105may be detected with an electrode. The liquid level sensor155may also output different signals for different liquid levels in the first reservoir53of the ink cartridge50, instead of outputting different signals for different liquid levels in the second reservoir105of the subtank100.

In the above embodiments, the controller230performs the processing in steps S15and S145in response to a low-level signal, a high-level signal, and a low-level signal received in the stated order from the installation sensor154. The controller230performs the processing in steps S15and S145in response to the ink cartridge50installed in the installation case71previously containing no ink cartridge50. More specifically, the controller230may perform the processing in steps S15and S145when determining that the ink cartridge50is installed in the installation case71. The controller230receiving a low-level signal from the installation sensor154, then receiving a high-level signal from the installation sensor154, and further receiving a low-level signal from the installation sensor154is an example of the controller230determining that the cartridge is installed in the installation case71. Other examples of the controller230determining that the ink cartridge50is installed in the installation case71will be described below.

For example, the controller230receives a low-level signal after receiving a high-level signal from the cover sensor88. The controller230then reads identification information from the memory of the IC chip66and compares the read identification information with identification information for the ink cartridge50yet to be replaced stored in the EEPROM234. When determining that the identification information read from the memory of the IC chip66differs from the identification information stored in the EEPROM234, the controller230may perform the processing in steps S15and S145. More specifically, an example of the controller230determining that the ink cartridge50is installed in the installation case71includes the controller230reading identification information from the memory of the IC chip66and comparing the read identification information with identification information for the ink cartridge50yet to be replaced stored in the EEPROM234, and determining that the identification information read from the memory of the IC chip66differs from the identification information stored in the EEPROM234.

For example, the controller230receives a low-level signal after receiving a high-level signal from the cover sensor88. The controller230then displays, to the user, a confirmation screen on the display17indicating whether an ink cartridge50is newly installed in the installation case71. The controller230receives an input corresponding to the confirmation screen through the operation panel22while the confirmation screen appears on the display17. The controller230performs the processing in steps S15and S145when the received input corresponds to an ink cartridge50newly installed in the installation case71. More specifically, an example of the controller230determining that the ink cartridge50is installed in the installation case71includes the controller230receiving a low-level signal after receiving a high-level signal from the cover sensor88, displaying, to the user, a confirmation screen on the display17indicating whether an ink cartridge50is newly installed in the installation case71, and receiving an input corresponding to the confirmation screen through the operation panel22while the confirmation screen appears on the display17, with the received input then corresponding to an ink cartridge50newly installed in the installation case71.

In the above embodiments, when at least one of the four flags S_Empty is set ON, all the four subtanks100are disabled from discharging ink through the recording head39. The subtank100for which the flag S_Empty is set ON may be selectively disabled from discharging ink through the recording head39. When at least one of the flags S_Empty associated with magenta, cyan, and yellow is set ON, and the flag S_Empty associated with black is set OFF, the discharge of the magenta, cyan, and yellow inks may be disabled, and the discharge of the black ink may be enabled.

In the above embodiments, the controller230disables the ink discharge through the recording head39when the flag S_Empty is ON. However, the ink discharge through the recording head39may not be disabled, and the controller230may simply display the notification screen S_Empty on the display17when the flag S_Empty is ON.

The IC chip66is electrically connectable to the contact152through contact. However, an information medium and an interface such as near field communication (NFC) or radio frequency identification (RFID) may be used for reading and writing data in a contactless manner using radio waves.

In the embodiments described above, the ink is an example of liquid. However, the liquid may be a pretreatment liquid discharged to a sheet or another substrate before ink is applied in image recording, or may be water for cleaning the recording head39.