JP6322946B2 - Image recording apparatus and liquid cartridge - Google Patents

Description

  The present invention relates to an image recording apparatus and a liquid cartridge in which liquid is supplied from a liquid chamber to a recording head.

  In an image recording apparatus, ink is supplied to a recording head via a flow path from an ink cartridge or an ink tank that stores ink. When the ink stored in the ink cartridge or the like is consumed, it is necessary to replace the ink cartridge or replenish the ink. Therefore, a technique for determining the remaining amount of ink in the ink cartridge using optical means is known. For example, in a known image recording apparatus, an optical path plate is provided on the wall of the ink cartridge. If the inner surface of the optical path plate is in contact with the ink, the optical path plate transmits light into the ink. If the inner surface of the optical path plate is not in contact with the ink, the optical path plate totally reflects light on the inner surface. The remaining amount of ink is determined by detecting whether or not the light applied to the optical path plate from the light emitting unit is totally reflected (Patent Document 1).

  In addition, the configuration of determining the remaining amount of ink by detecting that the volume of the bag-shaped space that is continuous with the ink chamber in which the ink is stored has decreased due to the shrinkage of the bag shape as the ink is consumed. Have been devised (Patent Documents 2 to 5).

JP-A-5-332812 JP 59-204567 A JP 63-57238 A JP 2006-231528 A JP 2005-111955 A

  The configuration described in Patent Document 1 has a problem that the remaining amount of ink cannot be accurately detected if the optical path is stained with ink. On the other hand, the configurations described in Patent Documents 2 to 5 need to be an airtight space in which the ink chamber is not communicated with the atmosphere. If the ink chamber is an airtight space, the ink chamber must be contracted in order for the ink to smoothly flow out of the ink chamber. Therefore, the ink chamber is generally formed by a bag (pouch) that is easily contracted. However, there is a problem that the material of the bag is limited, and in the structure in which the ink chamber formed of the bag is accommodated in the case of the rectangular ink cartridge, the ink storage efficiency is poor with respect to the internal volume of the case. There is a problem.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a means capable of determining the remaining amount of liquid in a liquid chamber communicated with the atmosphere.

The image recording apparatus according to the present invention is connected to the atmosphere, has a liquid chamber in which the liquid is stored, a first flow path for allowing the liquid to flow out of the liquid chamber, and a second flow that is continuous with the first flow path. A pressure fluctuation section having a path, a recording head for discharging a liquid supplied via the second flow path, and a flexible film configured to be displaced according to the pressure in the second flow path And a detection unit that detects the position of the film of the pressure fluctuation unit, and a determination unit that determines the presence or absence of the liquid stored in the liquid chamber based on the detection of the detection unit. It flows to the recording head by the flow resistance R of the first flow path, the minimum pressure difference ΔP inside and outside the film necessary for displacing the film of the pressure fluctuation portion, and a predetermined operation of the recording head. The liquid flow rate I, which is the minimum value of the liquid flow rate,
There is a relationship of flow path resistance R ≧ minimum pressure difference ΔP / liquid flow rate I.
Needless to say, the flow path resistance R is a resistance generated when the liquid stored in the liquid chamber flows through the first flow path.

  The predetermined operation of the recording head may be, for example, an operation in which a carriage on which the recording head is mounted moves once in the scanning direction, a flushing operation of the recording head, or a recording medium An image recording operation in which the liquid flow rate necessary for printing an image is estimated to be equal to or higher than the liquid flow rate I may be used.

  When the recording head performs a predetermined operation in a state where the liquid is stored in the liquid chamber and the liquid flows to the recording head at a flow rate equal to or higher than the liquid flow rate I, the flow path resistance R and the liquid flow rate in the first flow path. A pressure loss equal to or greater than the product RI with I occurs. That is, the pressure in the second flow path decreases by RI or more. Since there is a relationship of flow path resistance R ≧ minimum pressure difference ΔP / liquid flow rate I, when the pressure in the second flow path decreases by RI or more, the pressure difference between the inside and outside of the membrane of the pressure fluctuation portion becomes smaller than the minimum pressure difference ΔP. The film becomes larger and the film is displaced. The position of the displaced film is detected by the detection unit. On the other hand, when the liquid in the liquid chamber is consumed and air enters the first flow path, the flow path resistance R of the first flow path starts to decrease, and when the inside of the first flow path becomes almost air, The channel resistance R becomes almost zero. Therefore, even if the liquid flows to the recording head at a flow rate equal to or higher than the liquid flow rate I, the pressure loss in the first flow path is almost zero, so the film of the pressure fluctuation portion does not move. In this manner, the detection unit detects the position of the film of the pressure fluctuation unit that is displaced based on the presence or absence of ink in the first flow path, and the determination unit is stored in the liquid chamber based on the detection information of the detection unit. The presence or absence of ink is determined.

Further, the present invention is a liquid cartridge that is attached to and detached from the cartridge mounting portion in an apparatus having a recording head that discharges the liquid supplied from the liquid cartridge via the cartridge mounting portion, and is in air communication. A liquid chamber in which the liquid is stored, a first flow path for allowing the liquid to flow out of the liquid chamber, the first flow path, and a second flow path continuous with the liquid supply port for flowing the liquid to the outside, A pressure fluctuation portion having a flexible film configured to be displaced according to the pressure in the second flow path, and the flow path resistance R of the first flow path and the pressure The minimum pressure difference ΔP inside and outside the film necessary for displacing the film of the variable portion and the liquid flow rate I which is the minimum value of the liquid flow rate flowing to the print head in a predetermined operation of the print head are
It may be regarded as a liquid cartridge having a relationship of flow path resistance R ≧ minimum pressure difference ΔP / liquid flow rate I.

  According to the present invention, when the recording head performs a predetermined operation and a liquid flows to the recording head at a flow rate equal to or higher than the liquid flow rate I, the product of the flow path resistance R and the liquid flow rate I in the first flow path is equal to or greater than RI. Depending on whether or not the pressure loss occurs, the pressure in the second flow path changes and it is determined whether or not the film of the pressure fluctuation portion is displaced. Therefore, it is detected whether or not the film is displaced. Thus, the remaining amount of liquid in the liquid chamber communicated to the atmosphere can be determined.

FIG. 1 is a schematic cross-sectional view schematically showing the internal structure of a printer 10 according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing the internal configuration of the ink cartridge 30. 3A is an enlarged cross-sectional view showing a cross section of the pressure fluctuation portion 47 in a state where the diaphragm rubber 49 has a dome shape, and FIG. 3B shows the diaphragm rubber 49 moving toward the space of the cylindrical portion 48. It is an expanded sectional view which shows the cross section of the pressure fluctuation | variation part 47 of the bent state. FIG. 4 is a block diagram illustrating a configuration of the control unit 90. FIG. 5 is a flowchart showing a procedure for determining the remaining amount of ink. FIG. 6 is a schematic cross-sectional view of an ink supply device 100 according to a modification. FIG. 7 is a longitudinal sectional view showing the internal configuration of the ink cartridge 30 according to the modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. The embodiment described below is merely an example in which the present invention is embodied, and it is needless to say that the embodiment can be appropriately changed without departing from the gist of the present invention.

[Overview of Printer 10]
As shown in FIG. 1, a printer 10 as an example of an image recording apparatus records an image by selectively ejecting ink droplets onto a recording sheet based on an inkjet recording method. The printer 10 includes an ink supply device 100. The ink supply device 100 is provided with a cartridge mounting portion 110. The ink cartridge 30 can be mounted on the cartridge mounting unit 110. The cartridge mounting portion 110 is provided with an opening 112 whose one surface is open to the outside. The ink cartridge 30 is inserted into or removed from the cartridge mounting part 110 through the opening 112.

  The ink cartridge 30 stores ink that can be used by the printer 10. In a state where the ink cartridge 30 is mounted on the cartridge mounting portion 110, the ink cartridge 30 and the recording head 29 are connected by the ink tube 20 via the sub tank 28. The sub tank 28 and the recording head 29 are mounted on the carriage 21. The sub tank 28 temporarily stores the ink supplied through the ink tube 20. The carriage 21 receives a driving force from a motor (not shown) and reciprocates in the direction (scanning direction) perpendicular to the paper surface of FIG. 1 along the recording surface of the recording paper. The recording head 29 selectively ejects ink supplied from the sub tank 28 from the nozzles while moving in the scanning direction together with the carriage 21 by the ink jet recording method.

  The recording paper fed from the paper feed tray 15 to the transport path 24 by the paper feed roller 23 is transported onto the platen 26 by the transport roller pair 25. A recording head 29 mounted and moved on the carriage 21 selectively ejects ink while being scanned with respect to the recording paper passing over the platen 26. Thereby, an image is recorded on the recording paper. The recording sheet that has passed through the platen 26 is discharged by a discharge roller pair 22 to a discharge tray 16 provided on the most downstream side of the transport path 24.

  Note that the schematic configuration of the printer 10 according to the present embodiment is merely an example. For example, other configurations in a known inkjet printer may be employed for the recording paper feeding method, the conveying method, the shape of the conveying path, and the like. Needless to say, it is good.

[Ink supply apparatus 100]
As shown in FIG. 1, the ink supply device 100 is provided in the printer 10. The ink supply device 100 supplies ink to the recording head 29 provided in the printer 10. The ink supply device 100 includes a cartridge mounting unit 110 in which the ink cartridge 30 can be mounted. FIG. 1 shows a state where the ink cartridge 30 is mounted on the cartridge mounting portion 110.

[Ink cartridge 30]
As shown in FIG. 2, the ink cartridge 30 is a container for storing ink. A space formed inside the ink cartridge 30 is an ink chamber 36 for storing ink. The ink chamber 36 may be a space formed by the casing 31 that forms the appearance of the ink cartridge 30, or may be formed by a member that is disposed inside the casing 31 and is different from the casing 31. It may be a space.

  The ink cartridge 30 is in the standing state shown in FIG. 2, that is, the direction indicated by the arrow 50 with respect to the cartridge mounting portion 110 with the lower surface in the drawing as the bottom surface and the upper surface in the drawing as the top surface. (Hereinafter referred to as “insertion and removal direction 50”). In other words, the ink cartridge 30 is inserted into the cartridge mounting portion 110 along the insertion / removal direction 50 and is removed from the cartridge mounting portion 110 along the insertion / removal direction 50. The ink cartridge 30 is inserted into and removed from the cartridge mounting portion 110 while standing. This standing state corresponds to a mounting posture in which the ink cartridge 30 is mounted in the cartridge mounting portion 110. The direction in which the ink cartridge 30 is inserted into the cartridge mounting portion 110 is the insertion direction 56, and the direction in which the ink cartridge 30 is removed is the extraction direction 55. Needless to say, the insertion direction 56 and the extraction direction 55 are parallel to the insertion and extraction direction 50. In the present embodiment, the insertion and removal direction 50 is along the horizontal direction. That is, the insertion direction 56 and the extraction direction 55 are directions along the horizontal direction.

  The ink cartridge 30 has a substantially rectangular parallelepiped housing 31. The casing 31 has a flat shape that is short in the width direction (a direction perpendicular to the paper surface of FIG. 2), and whose height direction 52 and depth direction 53 are longer than the width direction. The width direction and the depth direction 53 are along the horizontal direction when the ink cartridge 30 is in the mounting posture. The height direction 52 is along the vertical direction when the ink cartridge 30 is in the mounting posture. When the ink cartridge 30 is inserted into and removed from the cartridge mounting portion 110, the depth direction 53 is parallel to the insertion and removal direction 50, and the width direction and the height direction 52 are orthogonal to the insertion and removal direction 50.

  The housing 31 has a front wall 40 and a rear wall 42. When the ink cartridge 30 is inserted into the cartridge mounting portion 110, the wall of the casing 31 that is the front side of the insertion direction 56 is the front wall 40, and the wall of the casing 31 that is the rear side is the rear wall 42. The front wall 40 and the rear wall 42 face each other in the depth direction 53 (insertion and extraction direction 50). Although not shown in the figure, the housing 31 has a pair of side walls that connect the front wall 40 and the rear wall 42 and extend in the insertion and extraction direction 50. The side walls are opposed in the width direction. The casing 31 further connects the side wall with the front wall 40 and the rear wall 42, and extends from the upper end of the front wall 40 toward the upper end of the rear wall 42, and from the lower end of the front wall 40 to the rear wall. A lower wall 41 extending toward the lower end of 42 is provided. The upper wall 39 and the lower wall 41 face each other in the height direction 52.

  As shown in FIG. 2, an ink supply unit 43 is provided below the height direction 52 of the front wall 40 of the housing 31. The ink supply unit 43 has a cylindrical outer shape and protrudes from the front wall 40 to the outside of the housing 31 along the depth direction 53 (insertion and extraction direction 50), that is, protrudes in the insertion direction 56. Yes. An ink supply port 45 that opens to the outside of the housing 31 is formed at the tip of the ink supply unit 43. An ink flow path 44 is formed inside the ink supply unit 43. The ink flow path 44 extends in the depth direction 53 (insertion and removal direction 50) from the ink supply port 45 and communicates with the ink chamber 36 via the first ink outflow path 61 and the second ink outflow path 62.

  Although not shown in detail in the drawing, the ink supply port 45 is liquid-tightly sealed with a film, a valve, or the like that closes the ink supply port 45. The film and the valve are broken or opened when the ink introduction tube 122 of the cartridge mounting unit 110 is inserted into the ink supply port 45. Further, at the tip of the ink supply unit 43, a portion surrounding the ink supply port 45 is formed by an elastic member such as rubber that can come into liquid-tight contact with the peripheral wall of the ink introduction tube 122.

  As shown in FIG. 2, an air communication part 46 is provided on the upper side of the height direction 52 in the front wall 40 of the housing 31. The atmosphere communication portion 46 is a hole that penetrates the front wall 40 at a location where the air layer of the ink chamber 36 exists. The air communication portion 46 is hermetically sealed by a film, a valve, or the like, and in the process of inserting the ink cartridge 32 into the cartridge mounting portion 110, the film is broken or the valve is opened, so that the ink chamber The air layer 36 and the atmosphere outside the ink cartridge 32 may communicate with each other, or the air layer in the ink chamber 36 and the atmosphere outside the ink cartridge 32 may communicate with each other by a labyrinth structure. As ink flows out from the ink chamber 36 into the ink introduction tube 122 provided in the cartridge mounting portion 110, the air flows into the ink chamber 36 through the air communication portion 46.

  As shown in FIG. 2, a pressure fluctuation portion 47 is provided in the center of the front wall 40 of the housing 31 in the height direction 52. The pressure fluctuation portion 47 protrudes from the front wall 40 along the depth direction 53 (insertion and extraction direction 50) to the outside of the housing 31, that is, protrudes in the insertion direction 56, a hollow cylindrical tube portion 48, A diaphragm rubber 49 is provided on the distal end side of the tubular portion 48 so as to close the opening on the distal end side of the tubular portion 48. The base end side of the cylindrical portion 48 has a smaller outer shape than the distal end side, and is attached to the front wall 40 so as to penetrate the front wall 40 in the depth direction 53. The inner space of the cylindrical portion 48 is open to the insertion direction 56 on the outer side of the front wall 40, and the inner space of the cylindrical portion 48 is reduced in diameter on the proximal end side of the cylindrical portion 48, The second ink outflow passage 62 and the ink can be circulated continuously through 40.

  The diaphragm rubber 49 has a swelled shape from the distal end side of the cylindrical portion 48 so as to cover the opening on the distal end side of the cylindrical portion 48. The diaphragm rubber 49 is a flexible thin film. The diaphragm rubber 49 is configured as a part of a wall that partitions the internal space of the cylindrical portion 48. The internal space of the cylindrical portion 48 whose opening is closed by the diaphragm rubber 49 is filled with ink. As shown in FIG. 3, is the diaphragm rubber 49 maintained in a dome shape depending on the relationship between the pressure of the ink filled in the internal space of the cylindrical portion 48 and the external atmospheric pressure (FIG. 3A)? ), Whether to bend toward the inner space of the cylindrical portion 48 is determined (FIG. 3B). That is, when the pressure of the ink filled in the internal space of the cylinder portion 48 varies, the diaphragm rubber 49 is displaced.

  When the diaphragm rubber 49 is maintained in a dome shape, a conductive material 38 is provided on the outer surface of the portion that is the most distal end of the diaphragm rubber 49 in the insertion direction 56. The conductive material 38 is made of a material capable of supplying a detection current flowing in the detection unit 114 provided in the case 101 of the cartridge mounting unit 110, and is exposed on the outer surface of the diaphragm rubber 49. In a state where the ink cartridge 30 is attached to the case 101, the conductive material 38 contacts and separates from the detection unit 114 with the displacement of the diaphragm rubber 49.

  The internal space of the cylinder part 48 of the pressure fluctuation part 47 is continuous with the second ink outflow path 62 communicating with the ink flow path 44 of the ink supply part 43 on the proximal end side of the cylinder part 48. The second ink outflow path 62 extends from the base end side of the cylindrical portion 48 along the front wall 40 of the housing 31 toward the lower wall 41 and continues to the ink flow path 44. The second ink outflow path 62 does not necessarily have a width corresponding to the entire region in the width direction of the casing 31, and is a channel having a width sufficiently smaller than the width of the casing 31, that is, a channel having a small cross-sectional area. It may be formed as. A flow path constituted by the ink tube 20, the ink flow path 44, and the second ink outflow path 62 corresponds to the second flow path.

  The second ink outflow path 62 is continuous with the first ink outflow path 61 leading to the ink chamber 36 at the upper end thereof. That is, the second ink outflow path 62 is continuous with the internal space of the cylindrical portion 48 in the insertion direction 56 at the upper end thereof, and is continuous with the first ink outflow path 61 in the removal direction 55. The first ink outflow path 61 extends from the end continuous with the second ink outflow path 62 along the front wall 40 of the housing 31 toward the lower wall 41, and further along the lower wall 41. The wall 40 and the rear wall 42 are U-turned a plurality of times. In other words, the wall 40 and the rear wall 42 are zigzagged along the insertion direction 56 and the extraction direction 55 like a zigzag and continue to the ink chamber 36. Accordingly, the ink flowing out from the ink chamber 36 reaches the internal space of the second ink outflow path 62 and the cylinder portion 48 of the pressure fluctuation section 47 through the first ink outflow path 61. The first ink outflow path 61 does not necessarily have a width corresponding to the entire width direction of the casing 31, and is a channel having a width sufficiently smaller than the width of the casing 31, that is, a channel having a small cross-sectional area. It may be formed as The first ink outflow path 61 corresponds to the first flow path. The ink that has flowed out of the ink chamber 36 reaches the ink flow path 44 through the first ink outflow path 61 and the second ink outflow path 62.

By the flow resistance R of the first ink outflow path 61, the minimum pressure difference ΔP inside and outside the diaphragm rubber 49 necessary for the displacement of the diaphragm rubber 49 of the pressure fluctuation portion 47, and a predetermined operation of the recording head 29. The ink flow rate I, which is the minimum value of the ink flow rate flowing to the recording head 29, is in the relationship of the following formula 1.
(Channel resistance R) ≧ (minimum pressure difference ΔP) / (ink flow rate I) (Equation 1)
The pressure difference between the inside and outside of the diaphragm rubber 49 is obtained by subtracting the pressure applied to the inner surface of the diaphragm rubber 49 facing the inner space of the cylindrical portion 48 from the pressure applied to the outer surface of the diaphragm rubber 49 facing the atmosphere. Value.

  Since the ink chamber 36 communicates with the atmosphere via the atmosphere communicating portion 46, the pressure of the ink in the ink chamber 36 is equal to the atmospheric pressure Pa. In a state where ink does not flow from the first ink outflow path 61 to the recording head 29, the pressure of the ink in the internal space of the first ink outflow path 61, the second ink outflow path 62, and the pressure fluctuation portion 47 is also atmospheric pressure Pa. It is. Since the pressure outside the diaphragm rubber 49 is also the atmospheric pressure Pa, the pressure difference inside and outside the diaphragm rubber 49 is zero, and the diaphragm rubber 49 is not displaced.

  When a predetermined operation is performed by the recording head 29 and ink flows through the first ink outflow passage 61 at a flow rate equal to or higher than the flow rate I, a pressure loss equal to or higher than the product RI of the flow path resistance R and the ink flow rate I occurs. . Therefore, the pressure of the ink in the second ink outflow path 62 that is continuous with the first ink outflow path 61 is equal to or less than the value obtained by subtracting RI from the atmospheric pressure Pa (Pa-RI). Since the pressure of the ink in the internal space of the pressure fluctuation portion 47 that is continuous with the second ink outflow path 62 is also less than (Pa-RI), the pressure difference between the inside and outside of the diaphragm rubber 49 is large outside the diaphragm rubber 49. It becomes RI or more which is the difference between the pressure Pa and the pressure in the diaphragm rubber 49 (Pa-RI). From (Equation 1), since RI is not less than the minimum pressure difference ΔP, the diaphragm rubber 49 is displaced. In other words, the ink flow rate I is the minimum flow rate required for the diaphragm rubber 49 to be displaced in the pressure fluctuation unit 47.

  By the way, the flow path resistance generated when air flows through the first ink outflow path 61 is sufficiently smaller than the flow path resistance when ink flows through the first ink outflow path 61 and can be regarded as substantially zero. . Therefore, when the ink in the ink chamber 36 is consumed and air enters the first ink outflow path 61, even if the ink flows into the recording head 29, the air in the first ink outflow path 61 enters the part. There is virtually no pressure loss. When the first ink outflow path 61 is completely filled with air, no pressure loss occurs in the first ink outflow path 61 even if ink flows to the recording head 29 at an ink flow rate I or higher. The pressure difference between the inside and outside of 49 is not substantially generated, and the diaphragm rubber 49 is not displaced. Accordingly, the presence or absence of ink in the ink chamber 36 can be determined by detecting whether or not the diaphragm rubber 49 is displaced when the recording head 29 performs a predetermined operation.

Further, the flow resistance R ′ of a part of the first ink outflow path 61 that is continuous with the second ink outflow path 62 and the inside / outside of the diaphragm rubber 49 necessary for displacing the diaphragm rubber 49 of the pressure fluctuation unit 47 are also illustrated. The minimum pressure difference ΔP and the ink flow rate I, which is the minimum value of the ink flow rate flowing to the recording head 29 by a predetermined operation of the recording head 29, preferably have the relationship of the following formula 2 as an additional condition. There may be.
(Channel resistance R ′) <(minimum pressure difference ΔP) / (ink flow rate I) (Expression 2)
In this case, when air enters the first ink outflow path 61 and only a part (part having the flow path resistance R ′) continuous with the second ink outflow path 62 is filled with ink, Even if ink flows to the recording head 29 at the ink flow rate I, the pressure loss in the first ink outflow path 61 becomes the product R′I of the flow path resistance R ′ and the ink flow rate I, which is smaller than the minimum pressure difference ΔP. . Therefore, the diaphragm rubber 49 is not displaced. Therefore, it can be determined that the ink in the ink chamber 36 has run out before the first ink outflow path 61 is completely filled with air. Actually, if the recording head 29 performs a predetermined operation, the ink may flow to the recording head 29 at a flow rate I ′ that is equal to or higher than the flow rate I. Even when only a portion (portion having flow resistance R ′) is filled with ink, the product R′I ′ of the flow resistance R ′ and the flow I ′ is smaller than the minimum pressure difference ΔP. However, if (Expression 2) is satisfied, the frequency at which it can be determined that the ink in the ink chamber 36 has run out before the first ink outflow path 61 is completely filled with air. Can be said to increase.

[Cartridge mounting part 110]
As shown in FIG. 1, the case 101 forming the housing of the cartridge mounting unit 110 has an opening 112 on the front side of the printer 10. The ink cartridge 30 is inserted into and removed from the case 101 through the opening 112. The case 101 can accommodate four ink cartridges 30 corresponding to each color of cyan, magenta, yellow, and black, but only the case 101 corresponding to one ink cartridge 30 is shown in FIG. .

  The case 101 is located on the opposite side of the opening 112 in the insertion and extraction direction 50 and has a back surface facing the internal space of the case 101, and a connecting portion 103 is provided at a lower portion of the back surface of the case 101. ing. The connecting portion 103 is disposed on the back surface at a position corresponding to the ink supply portion 43 of each ink cartridge 30 attached to the case 101.

  The connection unit 103 has an ink introduction tube 122. The ink introduction tube 122 is connected to the ink tube 20 on the outer surface of the wall that forms the inner surface of the case 101. Each ink tube 20 connected to each ink introduction tube 122 is extended to the recording head 29 of the printer 10 so that ink can be distributed.

  As shown in FIG. 1, when the ink cartridge 30 is attached to the cartridge attachment portion 110, the ink introduction tube 122 of the connection portion 103 is inserted into the ink supply port 45 of the ink supply portion 43 and stored in the ink chamber 36. Ink can flow out of the ink cartridge 30. The ink that has flowed out of the ink chamber 36 flows into the ink introduction pipe 122 through the first ink outflow path 61, the second ink outflow path 62, and the ink flow path 44, and then flows into the recording head 29 through the ink tube 20.

  As shown in FIGS. 1 and 3, a detection unit 114 is provided at a position corresponding to the pressure fluctuation unit 47 of the ink cartridge 30 attached to the case 101 on the back surface of the case 101. The detection unit 114 includes a pair of conduction units 115 and 116 that are spaced apart in the vertical direction on the surface on the opening 112 side. The detection unit 114 outputs an electrical signal corresponding to the conduction state of the conduction units 115 and 116. When the diaphragm rubber 49 of the pressure fluctuation part 47 is dome-shaped, the conductive material 38 comes into contact with the conduction parts 115 and 116 to make the conduction parts 115 and 116 conductive. When the conductive material 38 is separated from the conductive portions 115 and 116 in accordance with the displacement of the diaphragm rubber 49, the conduction of the conductive portions 115 and 116 is interrupted. Thereby, the detection part 114 will detect the position of the diaphragm rubber 49, and will output an electrical signal.

  As shown in FIG. 1, the case 101 is provided with a lock lever 145. The lock lever 145 is for maintaining the ink cartridge 30 mounted on the cartridge mounting unit 110 in the mounted state. The lock lever 145 is provided near the opening 112 of the case 101.

  The lock lever 145 is formed in an arm shape as a whole, and can be rotated around a support shaft 147 provided near the center. One end of the lock lever 145 entering the inside of the case 101 has an ink Engage with the cartridge 30 to stop the ink cartridge 30 from moving in the take-out direction 55. As a result, the ink cartridge 30 is kept attached to the case 101. When the lock lever 145 is rotated, one end is separated from the ink cartridge 30 and the ink cartridge 30 can be taken out from the opening 112 of the case 101.

[Control unit 90]
Hereinafter, the schematic configuration of the control unit 90 of the printer 10 will be described with reference to FIG.

  The control unit 90 controls the overall operation of the printer 10. The control unit 90 is configured as a microcomputer mainly including a CPU 91, a ROM 92, a RAM 93, an EEPROM 94, and an ASIC 95. The control unit 90 corresponds to a determination unit and an estimation unit.

  The ROM 92 stores a program for the CPU 91 to control various operations of the printer 10, a program for executing determination processing described later, and the like. The RAM 93 is used as a storage area for temporarily recording data, signals, and the like used when the CPU 91 executes the program, or as a work area for data processing. The EEPROM 94 stores settings, flags, and the like that should be retained even after the power is turned off.

  A detection unit 114 is connected to the ASIC 95. Although not shown in FIG. 4, a drive circuit that drives each of the rollers such as the paper feed roller 23 and the transport roller pair 25, an input unit for inputting a print start command and the like to the printer 10, a computer, etc. An interface for transmitting / receiving data to / from the external connection device and a display unit for displaying information related to the printer 10 are also connected.

  The detection unit 114 outputs an analog electrical signal (voltage signal or current signal) corresponding to the conductive state of the conduction units 115 and 116. The control unit 90 monitors the electric signal output from the detection unit 114 at a predetermined timing, and determines that the electric signal level (voltage value or current value) is equal to or higher than a predetermined threshold value as an HI level signal. When it is less than a predetermined threshold, it is determined as a LOW level signal. One of the HI level signal and the LOW level signal is a signal indicating that the diaphragm rubber 49 is displaced, and the other is a signal indicating that the diaphragm rubber 49 maintains a dome shape.

[Determination of ink remaining amount of ink cartridge 30]
Hereinafter, the ink remaining amount determination of the ink cartridge 30 mounted on the cartridge mounting unit 110 will be described with reference to FIGS.

  As shown in FIG. 1, the control unit 90 receives a print start command in a state where the ink cartridge 30 is mounted in the cartridge mounting unit 110. The print start command is transmitted from, for example, a printer driver installed in a computer to which the printer 10 is connected, or transmitted from the input unit in response to the start button being pressed in the input unit of the printer 10. .

  Upon receiving the print start command, the control unit 90 calculates the amount of ink ejected from the recording head 29 while the carriage 21 is next scanned once in one way based on the bitmap data included in the print data (step 1; S1). The bitmap data indicates which size of a dot, that is, a large ink droplet, a medium ink droplet, or a small ink droplet is ejected to which position on the recording medium. The bitmap data may be created by a printer driver installed in the computer, or may be created by the control unit 90.

  Based on the print mode information included in the print data, the control unit 90 calculates the time required for the carriage 21 to scan once in one way (step 2; S2). This time may be stored in advance in the control unit 90 as a table corresponding to the print mode, for example. The print mode is, for example, a high resolution mode or a low resolution mode. The control unit 90 divides the ink amount described above by this time, so that the ink flow rate I flowing from the first ink outflow path 61 of the ink cartridge 30 to the recording head 29 while the carriage 21 is scanned once in one way. '' Is calculated (step 3; S3).

  The controller 90 determines whether or not the calculated ink flow rate I ″ is equal to or greater than a predetermined threshold (Step 4; S4). This threshold value is the minimum ink flow rate I necessary for the diaphragm rubber 49 to be displaced in the pressure fluctuation portion 47 of the ink cartridge 30. If (ink flow rate I ″) <(ink flow rate I) (step 4 (No)), the control unit 90 starts one-way scanning of the carriage 21 and ejects ink droplets from the recording head 29. (Step 5; S5), and then a film detection flag is set (Step 6; S6). Specifically, a flag is set in the register of the ASIC 95. Since (ink flow rate I ″) <(ink flow rate I), the diaphragm rubber 49 is not actually displaced, but in step 6, a film detection flag is set for convenience.

  If (ink flow rate I ″) ≧ (ink flow rate I) (step 4 (Yes)), the control unit 90 starts one-way scanning of the carriage 21 and ejects ink droplets from the recording head 29. At the same time, the timer is activated (step 7; S7). The control unit 90 monitors whether or not a predetermined time has passed by the timer (step 8; S8), and the detection unit 114 outputs an electrical signal indicating that the diaphragm rubber 49 has been displaced. Is determined (step 9; S9). When it is determined in step 4 that (ink flow rate I ″) ≧ (ink flow rate I), the operation of the recording head 29 that moves once in the scanning direction while ejecting ink droplets is determined in advance. It corresponds to the operation.

  When ink remains in the ink chamber 36 of the ink cartridge 30, that is, when all of the first ink outflow path 61 is filled with ink, the ink flow rate I ′ that is equal to or higher than the ink flow rate I is the first ink outflow path. By flowing through 61, a pressure loss corresponding to the product RI ′ of the flow path resistance R and the ink flow rate I ′ occurs, the pressure in the internal space of the pressure fluctuation portion 47 decreases, and the diaphragm rubber 49 It bends, that is, displaces toward the internal space (see FIG. 3B). When the ink flow rate is reduced and the pressure in the internal space of the pressure fluctuation portion 47 is increased, the bent diaphragm rubber 49 is elastically restored to a dome shape. Accordingly, ink flows from the second ink outflow path 62 into the internal space of the pressure fluctuation unit 47.

  If no ink remains in the ink chamber 36 of the ink cartridge 30 and the first ink outflow path 61 is filled with air, the first ink outflow path 61 may be supplied even if the ink flows into the recording head 29 at the ink flow rate I ′. No substantial pressure loss occurs and the diaphragm rubber 49 maintains the dome shape (see FIG. 3A). In particular, when (Equation 2) is satisfied, only a part of the first ink outflow path 61 that is continuous with the second ink outflow path 62 (part having the flow path resistance R ′) is filled with ink. Therefore, even if ink flows to the recording head 29 at the ink flow rate I ′, a pressure loss sufficient to displace the diaphragm rubber 49 does not occur in the first ink outflow path 61, and the diaphragm rubber 49 has a dome shape. The situation of maintaining may occur (see FIG. 3A). That is, there may occur a situation in which the diaphragm rubber 49 is not bent before the first ink outflow path 61 is completely filled with air.

  When the control unit 90 determines that the detection unit 114 has output an electric signal indicating that the diaphragm rubber 49 has been displaced (step 9 (Yes)), the control unit 90 sets a film detection flag. Specifically, the control unit 90 sets a flag in the ASIC 95 register. Stand up (step 10; S10). When it is not determined that the detection unit 114 has output an electrical signal indicating that the diaphragm rubber 49 has been displaced (Step 9 (No)), monitoring is continued until a predetermined time has elapsed (Step 8 (No)). ). If it is not determined that the detection unit 114 has output an electrical signal indicating that the diaphragm rubber 49 has been displaced even after a predetermined time has elapsed, the control unit 90 does not set the film detection flag (step 8 (Yes )).

  When the one-way scanning of the carriage 21 is completed (step 11 (Yes); S11), the controller 90 determines whether or not the film detection flag is set (step 12; S12). If the film detection flag is set (step 12 (Yes)), the control unit 90 clears the film detection flag (step 13; S13). If the film detection flag is not set (step 12 (No)), it is determined that there is no ink remaining in the ink chamber 36 of the ink cartridge 30, printing is stopped (step 13; S 13), and error notification is performed. .

  The control unit 90 determines whether or not all scanning of the image to be recorded on the recording medium has been completed (step 15; S15). If not completed (step 15 (No)), the carriage 21 is next. The ink amount ejected from the recording head 29 is calculated during one-time scanning of the ink (step 1). If completed (step 15 (Yes)), the printing operation is terminated.

[Effect of this embodiment]
According to the present embodiment, when the ink flow rate I ′ greater than or equal to the ink flow rate I flows to the recording head in a single one-way scan of the carriage 21, the flow path resistance R and the liquid flow rate I in the first ink outflow path 61. Since the pressure in the second ink outflow passage 62 changes depending on whether or not a pressure loss equal to or greater than the product RI of the pressure is generated, it is determined whether or not the position of the diaphragm rubber 49 of the pressure fluctuation portion 47 is displaced. When the detection unit 114 detects whether or not the ink has occurred, the control unit 90 can determine the remaining amount of ink in the ink chamber 36 communicated with the atmosphere.

  Further, when (Equation 2) is satisfied, before the first ink outflow path 61 is completely filled with air, the opportunity to determine that the ink in the ink chamber 36 has run out increases. Therefore, it is possible to prompt the user to replace the ink cartridge 30 before air enters the ink introduction tube 122. Since air does not enter the ink introduction pipe 122, the number of forced ink discharge operations (flushing) from the recording head 29 for discharging the air can be reduced.

[Modification]
In the present embodiment, the position of the diaphragm rubber 49 is electrically detected by the detection unit 114, but may be detected by optical, magnetic, or other known position detection means.

  In the present embodiment, the pressure fluctuation unit 47 is provided in the ink cartridge 30, but the pressure fluctuation unit in the present invention is not the ink cartridge 30, but the flow from the cartridge mounting unit 110 of the printer 10 to the carriage 21. It may be provided on the road. For example, as shown in FIG. 6, the pressure fluctuation portion 47 may be provided in the middle of the ink tube 20, and the detection portion 114 may be provided at a position corresponding to the pressure fluctuation portion 47.

  Further, the pressure fluctuation portion 47 is not limited to the form in which the opening of the cylindrical portion 48 is covered with the diaphragm rubber 49. For example, a sphere made of a flexible film in which atmospheric pressure air is confined in the second ink outflow path 62 may be disposed. In a state where the first ink outflow path 61 is filled with ink, when ink flows at a flow rate equal to or higher than the ink flow rate I, a pressure loss occurs in the first ink outflow path 61 and the pressure in the second ink outflow path 62 is increased. Decrease. Then, the pressure difference between the inside and outside of the sphere due to the flexible film becomes equal to or greater than the minimum pressure difference ΔP, and the sphere expands. When the sphere expands, buoyancy increases, and the sphere rises in the second ink outflow path 62. That is, the sphere by the flexible film is displaced. When ink is consumed and the inside of the first ink outflow path 61 is filled with air, even if ink flows at a flow rate equal to or higher than the ink flow rate I, no pressure loss occurs in the first ink outflow path 61. The sphere does not expand and displace. The controller 90 can determine the remaining amount of ink in the ink chamber 36 by optically detecting the position of the sphere, that is, the position of the film from outside the second ink outflow path 62.

  In this embodiment, the control unit 90 determines whether the ink flow rate I ″ based on the amount of ink ejected from the recording head 29 is equal to or higher than the ink flow rate I while the carriage 21 is scanned once in one way. However, if the operation is such that ink is ejected from the recording head 29, for example, the ink flow rate I ″ in the flushing operation, which is an operation not intended for image recording for maintenance of the recording head 29, is the ink amount. It may be determined whether or not it is equal to or greater than I. That is, the control unit 90 may determine the remaining amount of ink in the ink cartridge 30 within a predetermined time after the flushing operation is started. Further, instead of the ink flow rate I ″ based on the amount of ink ejected from the recording head 29 while the carriage 21 is scanned once in one way, the whole image or a part of the image to be printed on the recording medium is recorded. Therefore, it may be determined whether the ink flow rate I ″ based on the amount of ink discharged from the recording head 29 is equal to or higher than the ink flow rate I. That is, the controller 90 may determine the remaining amount of ink in the ink cartridge 30 while the carriage 21 is scanned a plurality of times.

  If the recording head 29 is a line head that is not scanned, whether or not the ink flow rate I ″ ejected from the recording head 29 is greater than or equal to the ink flow rate I every time the recording medium is conveyed by one step. May be determined. Further, when the recording head 29 is a line head, the ink amount for recording an image for one recording medium, the transport time of the recording medium for recording an image for one recording medium, and the like. The ink flow rate I ″ may be obtained by dividing by.

  Further, when the recording head 29 moves at a high speed in the scanning direction together with the carriage 21, acceleration is applied to the ink in the ink tube 20, and ink moves between the recording head 29 and the ink cartridge 30. Depending on the acceleration, the ink flow rate at that time may be equal to or higher than the ink flow rate I. That is, even if ink is not ejected from the recording head 29, the ink may flow at an ink flow rate I or higher simply by moving the recording head 29 in the scanning direction. In this case, the predetermined operation of the recording head 29 necessary for determining the remaining amount of ink may be an operation of moving the recording head 29 once in the scanning direction without ejecting ink from the recording head 29.

  As shown in FIG. 7, the casing 31 may have a plurality of bars 131 arranged in the depth direction 53 below the ink chamber 36. Each bar 131 extends in the width direction between the pair of side walls of the casing 31, and the cross-sectional shape parallel to the height direction 52 and the depth direction 53 is an inverted triangular shape. At least a part of the first ink outflow path 161 corresponding to the first flow path is formed by a space between the adjacent bars 131. The magnitude of the flow path resistance R of the first ink outflow path 161 depends on the size of the space between the adjacent bars 131. The size of the space between the adjacent bars 131 is set so that (Equation 1) is satisfied. In this modified example, even if the bubbles enter the first ink outflow path 161, the bubbles thereafter rise and can exit from the first ink outflow path 161 through the adjacent bars 131. Therefore, it is possible to reduce the bubbles that have entered the first ink outflow path 161 from adversely affecting the movement of the diaphragm rubber 49.

10 ... Printer (image recording device)
21 ... Carriage 30 ... Ink cartridge (liquid cartridge)
36 ... Ink chamber (liquid chamber)
39: Recording head 47 ... Pressure fluctuation part 49 ... Diaphragm rubber (film)
61... First ink outflow path (first flow path)
62... Second ink outflow path (second flow path)
90... Control unit (determination unit, estimation unit)
110... Cartridge mounting portion 114.

Claims (12)

A liquid chamber in which the atmosphere is communicated and the liquid is stored;
A first flow path for allowing liquid to flow out of the liquid chamber;
A second flow path continuous with the first flow path;
A recording head for discharging the liquid supplied through the second flow path;
A pressure fluctuation section having a flexible membrane configured to be displaced according to the pressure in the second flow path;
A detection unit for detecting the position of the film of the pressure fluctuation unit;
A determination unit that determines the presence or absence of the liquid stored in the liquid chamber based on the detection of the detection unit;
It flows to the recording head by the flow resistance R of the first flow path, the minimum pressure difference ΔP inside and outside the film necessary for displacing the film of the pressure fluctuation portion, and a predetermined operation of the recording head. The liquid flow rate I, which is the minimum value of the liquid flow rate,
Channel resistance R ≧ minimum pressure difference ΔP / liquid flow rate I
The image recording device in the relationship. The pressure fluctuation part has a space continuous with the second flow path, and the membrane is a part of a wall that partitions the space and bends toward the space.
The detection unit detects that the film of the pressure fluctuation unit is in a position bent toward the space,
The image recording apparatus according to claim 1, wherein the minimum pressure difference ΔP is a minimum pressure difference inside and outside the film necessary for the film of the pressure fluctuation portion to bend toward the space.   In the determination unit, the detection unit is in a position where the film of the pressure fluctuation unit is bent toward the space within a predetermined time after the recording head starts the predetermined operation. It is determined that there is liquid in the liquid chamber on the condition that this is detected, and the detection unit detects the pressure fluctuation within a predetermined time after the recording head starts the predetermined operation. The image recording apparatus according to claim 2, wherein it is determined that there is no liquid in the liquid chamber on the condition that it is not detected that the film of the portion is in a position bent toward the space.   The image recording apparatus according to claim 1, wherein the liquid chamber and the first flow path are provided in a liquid cartridge that is detachable from a cartridge mounting portion. A portion of the channel resistance R ′ that is continuous with the second channel in the first channel is:
The image recording apparatus according to claim 4, wherein the relationship of flow path resistance R ′ <minimum pressure difference ΔP / liquid flow rate I is satisfied.   The image recording apparatus according to claim 4, wherein the pressure fluctuation portion is provided in the liquid cartridge. The recording head is mounted on a carriage that moves in the scanning direction, and discharges liquid while the carriage moves.
The image recording apparatus according to claim 1, wherein the predetermined operation is an operation in which the recording head moves once in a scanning direction together with the carriage.   The image recording apparatus according to claim 1, wherein the predetermined operation is a flushing operation of the recording head. Based on bitmap data indicating an image to be recorded on the recording medium, the apparatus further includes an estimation unit that estimates whether the liquid flow rate necessary for printing the image is equal to or higher than the liquid flow rate I. ,
The predetermined operation is an image recording operation for the recording head to record an image that the estimation unit estimates that a liquid flow rate equal to or higher than the liquid flow rate I is required. The image recording apparatus described. A recording head for discharging liquid supplied from a liquid cartridge via a cartridge mounting unit, wherein the minimum value of the liquid flow rate flowing to the recording head by performing a predetermined operation is the liquid flow rate I. A liquid cartridge that can be attached to and detached from the cartridge mounting portion.
A liquid chamber in which the atmosphere is communicated and the liquid is stored;
A first flow path for allowing liquid to flow out of the liquid chamber;
A first flow path and a second flow path that is continuous with a liquid supply port for flowing the liquid to the outside;
A pressure fluctuation portion having a flexible film configured to be displaced according to the pressure in the second flow path,
The flow path resistance R of the first flow path, the minimum pressure difference ΔP inside and outside the film necessary for the film of the pressure fluctuation portion to be displaced, and the liquid flow rate I are:
Channel resistance R ≧ minimum pressure difference ΔP / liquid flow rate I
Liquid cartridge in the relationship. The pressure fluctuation part has a space continuous with the second flow path, and the membrane is a part of a wall that partitions the space and bends toward the space.
The liquid cartridge according to claim 10, wherein the minimum pressure difference ΔP is a minimum pressure difference between the inside and outside of the film necessary for the film of the pressure fluctuation portion to bend toward the space. In an apparatus having a recording head that discharges liquid supplied from a liquid cartridge via a cartridge mounting portion, the liquid cartridge is attached to and detached from the cartridge mounting portion.
A liquid chamber in which the atmosphere is communicated and the liquid is stored, the liquid chamber positioned between the front wall and the rear wall of the liquid cartridge ;
A first flow path comprising: a flow path from the rear wall toward the front wall; and a flow path connected to the flow path and positioned below the flow path and from the front wall toward the rear wall. A first flow path located below the liquid chamber and allowing the liquid to flow out of the liquid chamber;
A first flow path, and a second flow path that is disposed on the front wall and continues to a liquid supply port for flowing the liquid to the outside;
A pressure variation part having a film having elasticity, and a space formed by the film communicating with the inside of the second flow path;
The channel resistance of the first channel is larger than the channel resistance of the liquid chamber,
The channel resistance of the second channel is greater than the channel resistance of the liquid chamber,
The pressure fluctuation part is
A pressure difference obtained by subtracting the pressure inside the space generated by the discharge of ink from the recording head from the pressure outside the space results in the inside and outside of the space necessary for the film forming the space to be displaced. In response to the pressure difference being greater than the minimum pressure difference ΔP, the membrane is displaced to reduce the volume of the space, and the pressure difference is less than or equal to the minimum pressure difference ΔP. A liquid cartridge whose membrane is restored by elasticity .

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