JP2007218759A - Pressure detection control method and device, and liquid injection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure detection control method and a pressure detection control device capable of suppressing generation of dispersion of a pressure detection level, and controlling a control object properly based on a pressure detection result, and a liquid injection device equipped with the pressure detection control device. <P>SOLUTION: This pressure detection control device 70 includes a reflection plate 77 displaced following pressure fluctuation; a sensor substrate 78 for outputting the displacement of the reflection plate 77 as a detection value; and a control part 71 for determining whether the detection value output from the sensor substrate 78 agrees with a determination threshold corresponding to a set pressure set beforehand or not, and controlling so that an operation mode of a pump motor 45 agrees with a prescribed operation mode set beforehand when the determination result has an affirmative determination. The device 70 also includes a ROM 82 for storing the detection value corresponding to the actual displacement of the reflection plate 77 in a pressure condition of a pressure set beforehand as a determination threshold in pressure detection control using a pressure detector 34. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pressure detection control method, a pressure detection control device, and a liquid ejecting apparatus.

  2. Description of the Related Art Inkjet printers (hereinafter referred to as “printers”) are widely known as liquid ejecting apparatuses that eject liquid onto a target. In this printer, a recording head (liquid ejecting head) is mounted on a reciprocating carriage, and ink (liquid) is supplied to the recording head from an ink cartridge (liquid container) mounted at a predetermined position of the printer. Printing is performed by ejecting ink onto a recording medium as a target from nozzles formed on the nozzle formation surface of the recording head.

  In such a printer, in the case of a printer of a type in which the ink cartridge is mounted at a different location from the carriage (so-called off-carriage type), an ink supply tube (liquid supply path) is provided between the ink cartridge and the recording head. And the ink in the ink cartridge needs to be supplied to the recording head via the tube. Therefore, in the case of an off-carriage type printer, for example, as described in Patent Document 1, a pump device having a pressure pump and a pressure detector is provided, and air is supplied between the pump device and the ink cartridge. It connects with the tube (pressurized gas supply path).

Based on the driving of the pump device, pressurized air (pressurized gas) is sent from the pump device side to the air chamber in the ink cartridge through the air supply tube, and the ink pack accommodated in the air chamber is crushed. By applying pressure, ink is delivered from the ink cartridge to the recording head via the ink supply tube. Further, when the pressure detector detects that the pressure in the air supply tube has become too high as the pump device is driven, it occurs when the pressure in the air supply tube becomes high by stopping the driving of the pump device. Generation of various adverse effects (for example, ink leakage) is suppressed.
JP 2000-352379 A

  By the way, in general, a pressure detector includes a displacement member (for example, a reflection plate integrated on an outer surface of a flexible film constituting one wall surface of a pressure chamber) that is displaced with pressure fluctuation based on pump driving, and the displacement member. And a position sensor (for example, a light projecting / receiving sensor) disposed opposite to each other in the displacement direction, and a change in the relative distance between the position sensor and the displacement member is captured as a pressure change. Then, when the relative distance between the displacement member and the position sensor becomes a threshold distance corresponding to a preset pressure with the pressure fluctuation based on the pump drive, a signal for stopping the pump drive is output from the position sensor. Therefore, no further unnecessary pump drive is performed.

  However, normally, in such a pressure detector, there are dimensional errors of various parts constituting the pressure detector and variations in sensitivity of the position sensor, and therefore the relative distance between the position sensor and the displacement member becomes the threshold distance. Even in this case, the actual pressure at that time may deviate from a preset pressure. That is, the pressure detection level may vary among the pressure detectors.

  Therefore, as shown in FIG. 8, for example, when there is a variation in the pressure detection level in each of the three pressure detectors A, B, C, the same detection value S0 is output from each pressure detector A, B, C. Even if it is done, the actual pressure values PA, PB, PC in the pressure detectors A, B, C corresponding to the detected value S0 may be different pressure values. That is, assuming that the pressure detection level of the pressure detector A is appropriate, the actual pressure value PB corresponding to the detection value S0 by the pressure detector B is higher than the set pressure (= PA), and the pressure detector The actual pressure value PC corresponding to the detected value S0 by C may be lower than the set pressure (= PA).

  Therefore, when using the pressure detector B in which the actual pressure at the time when the detected value S0 becomes the output threshold distance becomes higher than the set pressure, the pump is driven longer than necessary. In the worst case, there is a problem that ink leakage occurs due to excessive pressure. On the other hand, when the pressure detector C is used in which the actual pressure when the detection value S0 becomes the output threshold distance becomes lower than the set pressure, only a low pressure is applied to the ink cartridge to be pressurized. There was a problem that printing failure occurred due to insufficient ink supply.

  The present invention has been made in view of such circumstances. The purpose is to provide a pressure detection control method, a pressure detection control device, and such a pressure detection control device capable of suppressing the occurrence of variations in pressure detection levels and appropriately controlling a control object based on the pressure detection result. An object of the present invention is to provide a liquid ejecting apparatus.

  In order to achieve the above object, the pressure detection control method of the present invention detects in advance the amount of displacement in which a displacement member that is displaced in accordance with pressure fluctuation actually displaces under a preset pressure condition. Is detected as a determination threshold value for the displacement member, and then the actual displacement amount of the displacement member accompanying the pressure fluctuation is output as the detection value, and the detection value matches the determination threshold value. If the determination result is affirmative, control is performed so that the operation mode to be controlled becomes a predetermined operation mode set in advance.

  According to the present invention, even if the displacement amount of the displacement member and the detection sensitivity of the displacement amount vary, the detected value of the displacement amount of the displacement member and the determination threshold value are set when the preset pressure is reached. Since they coincide with each other, it becomes possible to appropriately control the operation mode of the control target so as to become the predetermined operation mode.

  On the other hand, the pressure detection control device of the present invention includes a displacement member that is displaced according to pressure fluctuation, a detection unit that outputs the displacement amount as a detection value when the displacement amount of the displacement member is detected, and an output from the detection unit. A determination means for determining whether or not the detected value coincides with a threshold value for determination corresponding to a preset set pressure, and when the determination result of the determination means is affirmative, A pressure detection control device including a control unit configured to control a predetermined operation mode set in advance, corresponding to an actual displacement amount of the displacement member under a pressure condition of the set pressure detected in advance by the detection unit Storage means for storing the detected value to be determined as the determination threshold value, wherein the determination means stores the detection value output from the detection means at the time of the pressure fluctuation in the storage means. It was to determine whether matching.

  According to this invention, even if there is a variation in the degree of displacement of the displacement member and the detection sensitivity of the detection means, the detection value corresponding to the displacement amount of the displacement member at the time of pressure fluctuation can be obtained in advance using the displacement member and the detection means. It is determined whether or not they coincide with the threshold value for determination corresponding to the actual displacement amount detected under the pressure condition of the set pressure. Therefore, the occurrence of variations in the pressure detection level can be suppressed in comparison with the set pressure, and the control target can be appropriately controlled based on the pressure detection result.

  In the pressure detection control device of the present invention, the control target is a drive source that causes the pressure fluctuation by flowing a fluid during driving, and the control means determines that the determination result of the determination means is affirmative. In such a case, the driving of the driving source is stopped.

  According to the present invention, when the set pressure is reached, the drive source is no longer driven unnecessarily, so that the noise level associated with the drive source can be suppressed and the length of the drive source can be reduced. It will also be possible to contribute to life extension.

  Further, in the pressure detection control device of the present invention, the displacement member is welded to the pressure chamber where the fluid flows with the pressure fluctuation as the driving source is driven so as to bend and deform with the pressure fluctuation in the pressure chamber. It is integrated with a flexible member, and the detection means is configured to capture a change in relative distance from the displacement member that is displaced as the flexible member is deformed as a pressure change.

  According to this invention, since the pressure in the pressure chamber does not exceed the set pressure and becomes high, and the flexible member is not bent and deformed more than necessary, the flexible member can be welded from the pressure chamber. It is possible to suppress the occurrence of pressure leak due to peeling beyond the range.

In addition, the pressure detection control device of the present invention further includes a biasing member that biases the flexible member in a direction that suppresses bending deformation of the flexible member based on pressure fluctuation in the pressure chamber. .
According to the present invention, since the flexible member quickly returns to the original state when the driving source is stopped, the response of pressure detection control can be improved.

  In the pressure detection control apparatus of the present invention, the storage means stores a numerical value individually corresponding to an actual displacement amount when the displacement member is displaced under the pressure condition of the set pressure as the determination threshold value. ing.

According to the present invention, it becomes possible to control the operation mode of the controlled object when the set pressure is reached at an accurate timing.
Further, in the pressure detection control device of the present invention, the storage means has a numerical value individually corresponding to a predetermined displacement amount range including an actual displacement amount when the displacement member is displaced under the pressure condition of the set pressure. It is stored as a threshold for determination.

According to the present invention, the threshold setting storage in the storage means can be simplified.
Furthermore, the liquid ejecting apparatus according to the present invention includes a liquid ejecting head capable of ejecting a liquid, and a liquid housing that supplies the stored liquid to the liquid ejecting head based on the pressure of the pressurized fluid when the pressurized fluid is supplied. A body, a drive source that is driven to supply the pressurized fluid to the liquid container while changing the pressure, and the pressure detection control device configured as described above.

  According to this invention, when the applied pressure of the pressurized fluid reaches the set pressure, the drive source is stopped to prevent the pressure of the pressurized fluid supplied to the liquid container from becoming excessive. Thus, the liquid is supplied from the liquid container to the liquid ejecting head side based on an appropriate pressure. Therefore, it is possible to suppress the occurrence of problems such as insufficient liquid ejection and liquid leakage.

Hereinafter, an embodiment in which the present invention is embodied in a so-called off-carriage type liquid ejecting apparatus including a pressure pump device will be described with reference to FIGS.
As shown in FIG. 1, an ink jet printer (hereinafter referred to as “printer”) 10 as a liquid ejecting apparatus according to the present embodiment includes a main body case 11 having a rectangular shape in plan view. A rod-shaped guide shaft 12 is installed in the main body case 11 along the left-right direction which is the longitudinal direction of the main body case 11, and a carriage 14 on which a recording head 13 as a liquid ejecting head is mounted on the guide shaft 12. It is inserted and supported so as to be movable along the longitudinal direction.

  In addition, a cartridge holder 15 is provided at a position outside the movement range of the carriage 14 in the main body case 11 (right end side position in FIG. 1), and a plurality (four in this embodiment) are provided on the cartridge holder 15. An ink cartridge 16 as a liquid container is detachably mounted. In this respect, the printer 10 of the present embodiment is not a so-called on-carriage type printer in which the ink cartridge 16 is mounted on the carriage 14 and moves together with the carriage 14, and the ink cartridge 16 is fixed at a different location from the carriage 14. It is configured as a so-called off-carriage type printer that is arranged and does not move with the carriage 14.

  A driving pulley 17 and a driven pulley 18 are rotatably supported at positions corresponding to both ends of the guide shaft 12 on the inner surface of the rear side wall (upper side wall in FIG. 1) of the main body case 11. An endless timing belt 19 is mounted between the driving pulley 17 and the driven pulley 18, and a carriage motor 20 fixed to the outer surface of the rear side wall of the main body case 11 is connected to the driving pulley 17. Therefore, the carriage 14 reciprocates in the main scanning direction (left and right direction in FIG. 1) along the guide shaft 12 based on the driving force of the carriage motor 20 transmitted via the timing belt 19.

  A platen 25 is provided in the main body case 11 below the guide shaft 12 so as to extend in the left-right direction. The platen 25 is a support base for supporting a sheet (not shown) as a target, and becomes a sub-scanning direction (downward in FIG. 1) orthogonal to the main scanning direction in the horizontal plane with the rotation of a paper feed motor (not shown). Paper is fed forward).

  On the carriage 14, a sub tank (also referred to as a valve unit) 26 for supplying ink (accommodating liquid) to the recording head 13 side is mounted. Each of the ink cartridges 16 and the sub tanks 26 is provided in a number corresponding to the number of ink colors (for example, black, yellow, magenta, and cyan) used in the printer 10 (four in this embodiment). The sub tank 26 is connected to each ink cartridge 16 individually corresponding to each ink color via an ink supply tube 27 as a liquid supply path. Each sub tank 26 temporarily stores ink taken from the ink cartridge 16 side via the ink supply tube 27, adjusts the stored ink to a predetermined pressure, and supplies the ink to the recording head 13 side. .

  A pressurizing unit 31 as a pressurizing pump device is mounted at a position above the cartridge holder 15 in the main body case 11. The pressurizing unit 31 is a device for sending pressurized air (pressurized fluid) to the ink cartridge 16 through an air supply tube 32 as a pressurized gas supply path, and includes a pressurizing pump 33, a pressure detector 34, and an air release valve. 35. The air supply tube 32 is branched into a plurality of tubes (four in this embodiment) by a distributor 36 disposed on the downstream side of the atmosphere release valve 35, and each branched tube is connected to each ink cartridge 16 one by one. Yes.

  As shown in FIGS. 1 and 2, each ink cartridge 16 has a rectangular box-shaped ink case 37, and an ink pack 38 in which ink as a liquid is enclosed is stored in the ink case 37. An ink supply connection port 39 is formed in a substantially intermediate position in the vertical direction on one side wall (right side wall in FIG. 2) of the ink case 37, and the ink supply connection port 39 is integrally formed with the ink pack 38. A cylindrical ink discharge port 38 a is fitted so that its tip is exposed to the outside of the ink case 37. The ink supply tube 27 extending toward the sub tank 26 is connected to the ink discharge port 38a.

  In addition, an air supply connection port 40 is formed through one side wall (right side wall in FIG. 2) of the ink case 37 at a position below the ink supply connection port 39. A cylindrical connection pipe 41 is fitted into the air supply connection port 40 so that one end (the right end in FIG. 2) is exposed to the outside of the ink case 37 and the other end faces the ink case 37. Are combined. Then, the tip of the air supply tube 32 extending from the pressure pump 33 side described above is connected to one end of the connection pipe 41 exposed to the outside of the ink case 37, whereby the ink case 37 is placed in the ink case 37. An air chamber 42 in an airtight state is formed between the inner surface of the ink pack 38 and the outer surface of the ink pack 38.

  When the pressurized air is introduced into the air chamber 42 of the ink case 37 in the ink cartridge 16 through the air supply tube 32 as the pressure pump 33 is driven, the air pressure (pressure force) of the pressurized air ), The ink pack 38 is crushed. Then, the ink in the ink pack 38 is crushed as described above, so that the ink in the ink pack 38 is supplied to the sub tank 26 side through the ink supply tube 27.

Next, the pressurizing unit 31 will be described with reference to FIG.
As shown in FIG. 3, the pressurizing unit 31 is integrally formed by attaching a plurality of members such as a pressurizing pump 33, a pressure detector 34, and an air release valve 35 on a metal mounting plate 44. It has a unitized structure that can be handled. On the mounting plate 44, the pressurizing pump 33 and the pressure detector 34 are connected via a first air supply tube 32a. On the mounting plate 44, the pressure detector 34 and the atmosphere release valve 35 are connected via a second air supply tube 32b. The atmosphere release valve 35 on the mounting plate 44 and the ink cartridge 16 on the cartridge holder 15 are connected via a third air supply tube 32c.

  The pressurizing pump 33 is a diaphragm pump, and includes a pump motor 45 serving as a pump drive source and a pump unit 46 that performs a pump operation based on the driving force of the pump motor 45. For example, a small DC motor is used as the pump motor 45, and a motor gear 47 is fixed to the output shaft 45a. Between the pump motor 45 and the pump unit 46, a gear mechanism 48 and a cam mechanism 49 capable of transmitting a driving force from the pump motor 45 side to the pump unit 46 side are provided. The rotational motion of the pump motor 45 is converted into a reciprocating linear motion via the gear mechanism 48 and the cam mechanism 49 and transmitted to the pump unit 46.

  In the mounting plate 44, a rectangular plate-like support wall 44a is vertically bent upward from a substantially central portion of one end side edge (right end side edge in FIG. 3) on the output shaft 45a side of the pump motor 45, and A holding wall 44b is bent vertically upward from a position corresponding to the position where the pump unit 46 is disposed at the other end of the opposite side. A circular locking hole 50 is formed at the center of the holding wall 44b. Further, on the mounting plate 44, a pair of support pieces 44 c are arranged at a predetermined interval in a direction parallel to the output shaft 45 a of the pump motor 45 at a position opposite to the holding wall 44 b and the position where the pump unit 46 is disposed. It is erected so that Each support piece 44c has a support hole 51 formed at the same height.

  As shown in FIG. 3, a first support shaft 52 is integrally formed on the support wall 44a so as to extend on the mounting plate 44 toward the pump motor 45 along the horizontal direction. The first support shaft 52 is formed with a large diameter at the base end side (right end side in FIG. 3) and a small diameter at the tip end side (left end side in FIG. 3). The first gear 53 is supported in a rotatable state. The first gear 53 has a gear configuration in which a large-diameter tooth portion 53 a and a small-diameter tooth portion 53 b are overlapped in the axial direction, and the motor gear 47 in which the large-diameter tooth portion 53 a is fixed to the output shaft 45 a of the pump motor 45. Are engaged.

  The pump unit 46 includes a diaphragm (bellows) 54 having one end (left end in FIG. 3) opened in a circular shape, and a lid unit 55 that closes an opening (not shown) of the diaphragm 54 in a sealed state. Therefore, in the pump part 46, the inside of the diaphragm 54 closed by the cover part 55 functions as the pump chamber 54a. The diaphragm 54 has a bellows shape with a plurality of side walls folded back, and is manufactured by blow molding a resin or the like. The diaphragm 54 can be expanded and contracted in the longitudinal direction (in the direction of arrow A shown in FIG. 3) based on the driving force from the pump motor 45, and the volume of the pump chamber 54a is increased or decreased with this expansion and contraction operation.

  A plurality (three in this embodiment) of claw portions 55a are formed on the end surface (left end surface in FIG. 3) of the lid portion 55 of the pump portion 46 on the side facing the holding wall 44b described above. The claw portion 55a is locked in the locking hole 50 of the holding wall 44b, so that the pump portion 46 is supported on the mounting plate 44 at one end side (that is, the lid portion 55 side). On the other hand, a pressing member 56 is attached to the other end of the diaphragm 54 (the right end in FIG. 3). The pressing member 56 includes a connecting plate 57 having a flat plate shape and a columnar piston 58 integrally formed with the connecting plate 57. The pressing member 56 is reciprocated in a horizontal direction parallel to the output shaft 45a of the pump motor 45 on the mounting plate 44 by inserting the piston 58 into the support holes 51 of the pair of support pieces 44c described above. It is configured to be able to move linearly.

  As shown in FIG. 3, a second gear 59 having a large-diameter tooth portion 59a that meshes with the large-diameter tooth portion 53a of the first gear 53 is disposed between the support pieces 44c. In the second gear 59, a cylindrical portion 59b having a diameter smaller than that of the tooth portion 59a is integrally formed in the axial direction from one side surface side (left side surface in FIG. 3) of the tooth portion 59a. The second gear 59 has a communication hole (not shown) communicating in the axial direction over both the tooth portion 59a and the cylindrical portion 59b. The second gear 59 is supported so as to be rotatable relative to the piston 58 by inserting the piston 58 through the communication hole.

  Further, a helical cam groove (not shown) is formed on the outer peripheral surface of the piston 58 in the pressing member 56, while the outer peripheral surface of the piston 58 is formed on the inner peripheral surface side of the cylindrical portion 59 b of the second gear 59. A protrusion (not shown) is formed that is slidably engaged with the formed cam groove (not shown). Therefore, when the pump motor 45 is rotated, the first gear 53 and the second gear 59 are rotated accordingly, and the projection on the second gear 59 side slides in the cam groove on the piston 58 side at that time. The rotational motion of the pump motor 45 is converted into the reciprocating linear motion of the piston 58. Then, as the piston 58 reciprocates linearly with the rotation of the pump motor 45, the diaphragm 54 repeats an expanded state (a solid line state in FIG. 3) and a contracted state (a one-dot chain line state in FIG. 3). It has become.

  Note that the lid 55 of the pump unit 46 has an intake port (not shown) that serves as an air inlet to the pump chamber 54a when the diaphragm 54 changes from the contracted state to the extended state, and the diaphragm 54 from the extended state. An exhaust port serving as a discharge port for pressurized air from the inside of the pump chamber 54a to the outside in the contracted state is formed (not shown). A one-way valve for intake that allows only air flow into the pump chamber 54a is provided at the intake port, and a one-way valve for exhaust that allows only flow of pressurized air to the outside of the pump chamber 54a is provided at the exhaust port. It is connected. Since the one-way valve for intake and the one-way valve for exhaust correspond to check valves, the pump unit 46 is configured such that the amount of pressurization increases each time the diaphragm 54 expands and contracts.

  When the piston 58 linearly moves (returns) to the anti-diaphragm side (right side in FIG. 3) as the pump motor 45 rotates, the diaphragm 54 extends from the contracted state shown by the one-dot chain line to the extended state shown by the solid line in FIG. At this time, the diaphragm 54 is in an intake state, and air is sucked into the pump chamber 54a from the intake port. On the other hand, when the piston 58 linearly moves (moves forward) to the diaphragm 54 side (left side in FIG. 3) as the pump motor 45 rotates, the diaphragm 54 changes from the expanded state shown by the solid line to the contracted state shown by the one-dot chain line in FIG. Shrink. At this time, the diaphragm 54 is in an exhaust state, and the pressure positioned on the ink cartridge 16 side through the air supply tube 32 from the exhaust connection pipe 46a (see FIG. 3) connected to the exhaust port of the pressurized air in the pump chamber 54a. It is sent to the detector 34.

  As shown in FIG. 3, the pressure detector 34 includes an input connection pipe 34a that serves as an inlet for pressurized air and an output connection pipe 34b that serves as an outlet for the taken-in pressurized air. The input connection pipe 34a is connected to the exhaust connection pipe 46a of the pump unit 46 through the first air supply tube 32a. On the other hand, the output connection pipe 34b is connected to the suction connection pipe 35a of the atmosphere release valve 35 via the second air supply tube 32b. The pressurized air that has flowed into the pressure detector 34 from the pump unit 46 side via the first air supply tube 32a is detected via the second air supply tube 32b while detecting pressure fluctuations by the pressure detector 34. After flowing into the atmosphere release valve 35, the ink is further supplied to the ink cartridge 16 side via the third air supply tube 32c.

  Further, a friction clutch mechanism 61 is disposed between the first gear 53 and the atmosphere release valve 35 on the mounting plate 44. As shown in FIG. 3, a second support shaft 62 is formed integrally with the support wall 44a at the right end side edge of the mounting plate 44 in parallel with the first support shaft 52, and the tip end side of the second support shaft 62 (FIG. 3). The third gear 63 is supported in a rotatable state on the left end side). The third gear 63 is held so that it does not fall off from the tip side of the second support shaft 62 by the holding force of a holding pin (not shown) fixed to the tip of the second support shaft 62.

  Further, as shown in FIG. 3, between the third gear 63 and the support wall 44a, a substantially disc-shaped driven component 64 having an arm portion 64a projecting radially from the outer peripheral surface is provided in the second support. It arrange | positions in the state inserted and supported so that rotation with respect to the axis | shaft 62 was possible. A coil spring 65 is disposed between the driven component 64 and the support wall 44a. One end (right end in FIG. 3) of the coil spring 65 contacts the side surface of the support wall 44a and the other end (FIG. 3). The left end) is held in a pressure accumulation state in contact with the side surface of the driven component 64.

  Therefore, when the third gear 63 rotates, the driven component 64 is brought into a state of frictional engagement with the third gear 63 by the pressing force of the coil spring 65 and is rotated together with the third gear 63. The protruding length of the arm portion 64a in the driven component 64 is set to a length that reaches the atmospheric release valve 35 when the driven component 64 rotates to the atmospheric release valve 35 side. Further, the reduction ratio by the friction clutch between the third gear 63 and the driven component 64 is set larger than the reduction ratio between the first gear 53 and the second gear 59.

  Incidentally, since the pump motor 45 rotates in both forward and reverse directions, in this embodiment, when the pump motor 45 rotates in the forward direction, the driven component 64 rotates in the direction to close the atmosphere release valve 35, and the pump motor 45 When the rotation is reversed, the air release valve 35 is configured to rotate in a direction to open the valve. In the present embodiment, the third gear 63, the driven component 64, and the coil spring 65 constitute a friction clutch mechanism 61.

Next, a specific configuration of the pressure detection control device 70 in the present embodiment will be described with reference to FIG.
As shown in FIGS. 4A and 4B, the pressure detection control device 70 includes the pressure detector 34 described above and a control unit 71 serving as a control unit that controls the drive state of the pump motor 45 described above. Yes. The pressure detector 34 has a bottomed box-like case body 72 opened on the upper side, and an inverted lid 73 having a flat bottom on the case body 72 has a flange portion 73a as a case. The body 72 is mounted so as to contact the upper end of the side wall 72a of the body 72. A film 74 as a flexible member is welded to the inner surface side (the lower surface side in FIGS. 4A and 4B) of the lid body 73 so as to be flush with the flange portion 73a. A pressure chamber 75 is formed inside. It should be noted that one side surface of the lid 73 (the right side surface in FIGS. 4A and 4B) projects sideways so that the input connection tube 34a and the output connection tube 34b communicate with the inside of the pressure chamber 75, respectively. It is installed.

  A pressure receiving plate 76 is bonded and fixed to the surface (the lower surface in FIGS. 4A and 4B) of the front and back surfaces of the film 74 that faces the inner bottom surface of the case body 72. A reflection plate 77 is attached as a displacement member capable of reflecting light. On the other hand, on the inner bottom surface of the case body 72, a sensor substrate 78 is fixed at a position facing the upper reflecting plate 77, and an optical sensor 79 is provided at a substantially central portion of the sensor substrate 78. A coil spring 80 as an urging member is interposed between the inner bottom surface of the case body 72 and the pressure receiving plate 76. Then, as shown in FIG. 4, the film 74 receives the biasing force of the coil spring 80, and the film 74 indicates the relative distance between the reflection plate 77 and the optical sensor 79 when the pressure chamber 75 is under no pressure condition. The film 74 is always urged upward so that the relative distance L is equal to (ie, the film 74 is restrained from being deformed downward by the coil spring 80).

  The optical sensor 79 projects light toward the upper reflecting plate 77 and receives the light reflected by the reflecting plate 77, thereby causing a relative distance L between the reflecting plate 77 and the optical sensor 79. , L1 are detected, and detection values corresponding to the detected relative distances L, L1 are output from the sensor substrate 78 to the control unit 71. In this embodiment, the sensor substrate 78 and the optical sensor 79 detect the amount of displacement of the reflecting plate (displacement member) 77 (in this embodiment, the amount of movement in the direction of shortening the relative distance L described above). In this case, detection means for outputting the displacement amount as a detection value is configured.

  On the other hand, the control unit 71 includes a CPU 81 that controls the operating state of the entire printer 10, and the CPU 81 executes various arithmetic processes using the RAM 83 as a work area based on a control program stored in the ROM 82. . In the present embodiment, the ROM 74 of the control unit 71 has the pressure chamber 75 of the pressure detector 34 in the pressure condition of the set pressure P0 preset as the upper limit pressure value, and the film 74 is bent and deformed downward. A detection value corresponding to the relative distance between the reflecting plate 77 and the optical sensor 79 is stored as a determination threshold value. In this regard, in the present embodiment, the ROM 82 functions as a storage unit that stores a determination threshold value in advance.

Here, a method of setting a threshold for determination with respect to the ROM 82 will be described with reference to FIG.
If there are three pressure detectors A, B, and C having different pressure detection levels, the pressure detector A having an appropriate pressure detection level when the pressure chamber 75 is in the pressure condition of the set pressure P0. Will output the detected value (= SA) corresponding to the set pressure P0 as the sensor output. Further, even when the same set pressure P0 is detected from the pressure detector B whose pressure detection level is inappropriate to the low pressure side, the detection value (= SB) lower than the detection value (= SA) in the pressure detector A is detected. It is output as a sensor output. Similarly, even when the same set pressure P0 is detected from the pressure detector C whose pressure detection level is inappropriate to the high pressure side, the detected value (= SC) higher than the detected value (= SA) in the pressure detector A. Is output as a sensor output.

  That is, even when the same set pressure P0 is detected, the pressure detection levels for the pressure detectors A, B, and C vary, so that different detection values are output from the pressure detectors A, B, and C. Will be. Such variations in the pressure detection level for each of the pressure detectors A, B, and C are usually likely due to a height error in the side wall 72a of the case body 72, variations in sensitivity of the optical sensor 79, and the like. Therefore, in order to eliminate such a variation in the pressure detection level when performing pressure detection control processing of the pressurized air sent from the pressure pump 33 to the ink cartridge 16 side, the ROM 82 of the control unit 71 stores each pressure. Determination thresholds SA, SB, SC individually corresponding to the set pressure P0 unique to each of the detectors A, B, C are set and stored.

  In the case of this embodiment, the pressure chamber 75 in the pressure detector 34 is previously set as the pressure condition of the set pressure P0 described above, and the actual relative distance between the reflector 77 and the optical sensor 79 in that case (for example, The detection value corresponding to the relative distance L1) shown in FIG. The detected value is stored in advance in the ROM 82 as a determination threshold value in the pressure detection control process using the pressure detector 34 in the present embodiment. Therefore, even if the pressure detection level is different when compared with other pressure detectors such as the pressure detectors A, B, and C shown in FIG. The determination threshold value corresponding to the above is stored in the ROM 82 of the control unit 71 in advance.

  Next, a pressure detection control processing routine by the control unit 71 configured as described above will be described with reference to a flowchart shown in FIG. As a premise, the pressure detector 34 of this embodiment has the same pressure detection level as the pressure detector A among the three pressure detectors A, B, and C shown in FIG. It is assumed that a determination threshold SA having the same value as the detection value (= SA) when the pressure detector A detects the set pressure P0 is stored.

  Now, when the control unit 71 drives the pump motor 45 to operate the pump unit 46, first, the control unit 71 reads the determination threshold value SA from the ROM 82 and temporarily stores it in the RAM 83 (step S11). Next, the pump motor 45 is driven to start the supply of pressurized air (step S12). Then, by the processing in step S12, the pressurized air is supplied from the pump unit 46 of the pressurizing pump 33 to the ink cartridge 16 side via the pressure detector 34 with pressure fluctuation in the pressurizing direction. The pressure detector 34 periodically detects the pressure of the pressurized air and outputs the detected value S0.

  Then, the control unit 71 determines whether or not the detection value S0 output from the sensor substrate 78 of the pressure detector 34 is equal to or greater than the determination threshold value SA temporarily stored in the RAM 83 (step S13). In this respect, the control unit 71 also functions as a determination unit that determines whether or not the detection value S0 matches the determination threshold value SA. In addition, when the determination result of step S13 is negative determination (NO), the control part 71 repeats the determination process of step S13 until the determination result becomes affirmation determination (YES).

  And if the determination result of step S13 becomes affirmation determination, the control part 71 will transfer a process to following step S14. And in this step S14, the control part 71 stops the drive of the pump motor 45, and complete | finishes a pressure detection control processing routine. Accordingly, thereafter, the pressure in the pressure chamber 75 of the pressure detector 34 gradually decreases, and when the pressure reaches a preset pressure value (for example, zero pressure value), the pressure detection control processing routine is performed again. Repeated.

Therefore, the operation of the printer 10 configured as described above will be described below, particularly focusing on the operation at the time of pressure detection control in the pressure unit 31.
In the pressurizing unit 31, the pressurizing pump 33 is driven when the ink is sent from the ink cartridge 16 side to the recording head 13 side. That is, as the pump motor 45 rotates forward, the pump unit 46 starts pumping operation, and the diaphragm 54 expands and contracts. When the diaphragm 54 is extended, air (atmosphere) is sucked into the pump chamber 54a from the intake port via the one-way valve for intake, and the pressure of the sucked air increases when the diaphragm 54 is repeatedly expanded and contracted. Then, the exhaust air is discharged into the first air supply tube 32a from the exhaust connection pipe 46a connected to the discharge port via the exhaust one-way valve.

  The pressurized air discharged into the first air supply tube 32a then reaches the atmosphere release valve 35 via the pressure detector 34 and the second air supply tube 32b sequentially. The pressurized air that has reached the atmosphere release valve 35 further passes through the third air supply tube 32c when the atmosphere release valve 35 is in a closed state, and then the air in the ink case 37 in the ink cartridge 16 is used. It is introduced into the chamber 42.

  When the pressurized air is introduced into the air chamber 42 of the ink case 37 in the ink cartridge 16, the ink pack 38 is crushed by the air pressure (pressurizing force) of the pressurized air. Ink is supplied to the sub tank 26 side through the ink supply tube 27. Then, the ink whose pressure is adjusted in the sub tank 26 is supplied to the recording head 13 side, and printing is executed by ejecting the ink from the recording head 13 onto the paper.

  When pressurized air is pressurized and supplied from the pressurizing pump 33 to the ink cartridge 16 as described above, the pressure detection control device 70 including the pressure detector 34 and the control unit 71 provided in the pressurizing unit 31 is used. The following pressure detection control is performed.

  That is, as shown in FIG. 4A, since the pressure in the pressure chamber 75 of the pressure detector 34 is zero before the start of pressurization, the film 74 is also bent downward by the biasing force of the coil spring 80. It is in a substantially horizontal state in which deformation is suppressed. Therefore, the relative distance L between the reflecting plate 77 and the optical sensor 79 is large, and a numerical detection value S0 corresponding to the relative distance L is output from the sensor substrate 78 to the control unit 71. Therefore, the controller 71 continues to drive the pump motor 45 because the determination result of step S13 in the pressure detection control processing routine shown in FIG.

  Then, when the pressure of the pressurized air sent from the pressurizing pump 33 to the ink cartridge 16 side via the pressure detector 34 is gradually increased with pressure fluctuations to reach the set pressure P0, FIG. As shown, the film 74 is bent downward and deformed in response to an increase in pressure in the pressure chamber 75. Therefore, the relative distance L1 (L1 <L) between the reflecting plate 77 and the optical sensor 79 is reduced, and a numerical detection value S0 corresponding to the reduced relative distance L1 is output from the sensor substrate 78 to the control unit 71. Is done. Therefore, the control unit 71 stops driving the pump motor 45 because the determination result of step S13 in the pressure detection control processing routine shown in FIG.

  Therefore, the noise level in the pressurizing unit 31 is lowered as the pump motor 45 is stopped, and the durability is improved because the pump motor 45 is not driven unnecessarily for a long time. Further, the film 74 in the pressure detector 34 is not subjected to an excessive pressure exceeding the set pressure P 0, so there is no possibility of peeling from the flange 73 a of the lid 73, and pressurized air leaks from the pressure detector 34. Such a situation is also suppressed.

  When the pressure in the pressure chamber 75 gradually decreases as the pump motor 45 is stopped, the film 74 receives the urging force of the coil spring 80 and is bent downward and deformed as shown in FIG. It quickly returns to the initial horizontal position shown in 4 (a). Then, the relative distance L between the reflecting plate 77 and the optical sensor 79 is increased, and a numerical detection value S0 corresponding to the relative distance L is output to the control unit 71. As a result, detection corresponding to the relative distance L is performed. Based on the input of the value S0, the control unit 71 starts driving the pump motor 45 again. Then, the pressurized air pressure supply operation from the pressure pump 33 to the ink cartridge 16 side via the pressure detector 34 is resumed.

Therefore, the following effects can be obtained in the above embodiment.
(1) When the relative distances L and L1 between the reflector 77 and the optical sensor 79 change due to the pressure fluctuation in the pressure chamber 75 of the pressure detector 34, the pressure is output according to the relative distances L and L1. It is determined whether or not the detected value S0 coincides with the threshold value for determination SA corresponding to the actual relative distance detected in advance using the pressure detector 34 under the pressure condition of the set pressure P0. . That is, even if the pressure detector 34 has a different pressure detection level in comparison with other pressure detectors, the detection value (= The determination threshold value SA) is output. Accordingly, when pressure detection control is performed, the occurrence of variations in the pressure detection level of each pressure detector can be suppressed, and the drive state of the pump motor 45 that is the control target can be controlled appropriately based on the pressure detection result.

  (2) When the pressure in the pressure chamber 75 of the pressure detector 34 reaches the set pressure P0, the pump motor (drive source) 45 is not driven any more unnecessarily. The noise level associated with the driving of the pump motor 45 can be suppressed. Moreover, since such useless driving is suppressed, it is possible to contribute to extending the life of the pump motor 45.

  (3) When the pressure in the pressure chamber 75 of the pressure detector 34 reaches the set pressure P0, the driving of the pump motor 45 is stopped, and the pressure in the pressure chamber 75 exceeds the set pressure P0 and becomes high. Therefore, the film 74 as the flexible member is not bent and deformed more than necessary. Therefore, there is a concern that the film 74 may be peeled off from the lid 73 when the pressure chamber 75 is in a high pressure condition, but in this embodiment, the film 74 has a welding limit from the pressure chamber 75. Since it is not peeled off, it is possible to suppress the adverse effect that the pressurized air leaks from the pressure detector 34.

  (4) When the pressure in the pressure chamber 75 decreases as the pump motor 45 stops driving, the film 74 is pressed downward to bend and deform from the original substantially horizontal state based on the urging force of the coil spring 80. Return to. Therefore, the response of the pressure detection control in the pressure detector 34 can be improved.

  (5) When the pressure in the pressure chamber 75 becomes the set pressure P0, the detected value S0 corresponding to the set pressure P0 and coincident with the determination threshold SA is transferred from the sensor substrate 78 of the pressure detector 34 to the control unit. Therefore, it is possible to control the drive stop of the pump motor 45 to be controlled at an accurate timing.

  (6) When viewed as the printer 10 as a whole, the pump motor 45 is stopped when the pressure of the pressurized air becomes equal to or higher than the set pressure P0, so that the pressurized air supplied to the ink cartridge 16 is reduced. An excessive pressure can be suppressed, and ink is supplied from the ink cartridge 16 to the recording head 13 based on an appropriate pressure. Accordingly, it is possible to suppress the occurrence of problems such as insufficient ink ejection from the recording head 13 and ink leakage.

The above embodiment may be changed to another embodiment (another example) as follows.
As shown in FIG. 7, when there are three pressure detectors A, B, and C having different pressure detection levels, the pressure detectors A and B having a slight difference (within an allowable range) in the pressure detection levels For the above, pressure detection control may be performed using the same threshold for determination. That is, as shown in FIG. 7, a plurality of threshold ranges (predetermined displacement ranges) S1 to S4 are set for detection value levels output as sensor outputs from the pressure detector, and the detection values are included in the same threshold range. The pressure detectors may use the same threshold for determination.

  In this example shown in FIG. 7, the detection value (= SA) output from the pressure detector A and the detection value (= SB) output from the pressure detector B are strictly different numerical values. Since both are included in the same threshold range S3, in the pressure detection control using the pressure detector A or the pressure detector B, the same determination threshold value is stored and used in the ROM 82 as the storage means. For example, one of the determination threshold value SA and the determination threshold value SB, or another determination threshold value included in the threshold range S3 other than the determination threshold values SA and SB is common to both the pressure detectors A and B. The determination threshold is stored in the ROM 82. Therefore, in the case of this another example, the threshold value setting storage for the ROM 82 is stored in correspondence with the detection values (= SA, SB, SC) from the pressure detectors A to C individually. It becomes simple.

  In the pressure detection control in the above embodiment, the pump motor 45 is stopped based on the detected value of the pressure detector 34 when the pressure of the pressurized air whose pressure fluctuates in the pressure increasing direction reaches the set pressure P0. You may embody in the control method which drives the pump motor 45 based on the detected value of the pressure detector 34 when the pressure of the pressurized air which fluctuates in a direction reaches a predetermined pressure.

  In the above embodiment, when the film 74 as the flexible member is made of a material that elastically returns from the bending deformation state shown in FIG. 4 (b) to the original substantially horizontal state shown in FIG. 4 (a). The coil spring 80 as the urging member may not be provided.

  In the above embodiment, when the pressure receiving plate 76 is made of a light-reflective metal material, the displacement member formed by the reflecting plate 77 is vapor-deposited on the lower surface of the pressure receiving plate 76. Alternatively, when the reflection surface is formed by bonding or the like, the pressure receiving plate 76 may be a displacement member.

  In the above embodiment, when the detection value S0 output from the pressure detector 34 matches the determination threshold value SA, in addition to the pump motor 45 (or instead of the pump motor 45), other control objects (for example, The driving state of the valve device may be controlled.

  In the above embodiment, the displacement amount of the displacement member (reflecting plate 77) faces, for example, the pressure chamber 75 other than the numerical value indicating the change in the relative distances L and L1 between the reflecting plate 77 and the optical sensor 79. Similar to the upper surface of the film 74, a numerical value indicating a change in the distance between the inner surface of the lid 73 facing the pressure chamber 75 can be used as appropriate.

  In the above-described embodiment, the pressurized fluid that is sent from the pressurized pump 33 side to the ink cartridge 16 side with the pump operation is not limited to pressurized air but may be a pressurized liquid. In this case, it is preferable to provide a seal structure that prevents such pressurized liquid from leaking out of the printer 10.

In the above embodiment, the storage means for storing the determination threshold value may be the RAM 83 instead of the ROM 82.
In the above embodiment, the printer 10 that ejects ink has been described as the liquid ejecting apparatus, but other liquid ejecting apparatuses may be used. For example, printing apparatuses including fax machines, copiers, etc., liquid ejecting apparatuses that eject liquids such as electrode materials and color materials used in the production of liquid crystal displays, EL displays, and surface emitting displays, and bio-organic materials used in biochip manufacturing It may be a liquid ejecting apparatus for ejecting a liquid or a sample ejecting apparatus as a precision pipette. Also, the liquid is not limited to ink, and may be applied to other liquids.

1 is a schematic plan view of an ink jet printer according to an embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of an ink cartridge. FIG. 3 is a plan view of a pressure unit that sends pressurized air to an ink cartridge. It is sectional drawing which shows schematic structure of a pressure detection control apparatus, (a) is sectional drawing when a pressure chamber is no-pressure, (b) is sectional drawing in case the pressure in a pressure chamber is set pressure. The graph explaining the setting method of the threshold value for determination. The flowchart which shows a pressure detection control processing routine. The graph explaining the setting method of the threshold value for determination in another example. The graph explaining the setting method of the threshold value for determination in the past.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printer as liquid ejecting apparatus, 13 ... Recording head as liquid ejecting head, 16 ... Ink cartridge as liquid container, 45 ... Pump motor as driving source, 70 ... Pressure detection control apparatus, 71 ... Control means and Control unit as determination means, 74 ... film as flexible member, 75 ... pressure chamber, 77 ... reflection plate as displacement member, 78 ... optical sensor constituting detection means, 79 ... sensor substrate constituting detection means 82, ROM as storage means, L, L1, relative distance, P0, set pressure, SA, SB, SC, threshold for determination, S0, detection value.

Claims (8)

In addition to detecting in advance the amount of displacement that the displacement member that displaces with pressure fluctuation actually displaces under the preset pressure condition, the detected value in that case is stored as a threshold for determination in the displacement member, Thereafter, when the actual displacement amount of the displacement member accompanying the pressure fluctuation is output as a detection value, it is determined whether or not the detection value matches the determination threshold value, and the determination result is affirmative determination A pressure detection control method for controlling the operation mode to be a predetermined operation mode set in advance. A displacement member that is displaced in accordance with pressure fluctuation;
Detection means for outputting the displacement amount as a detection value when the displacement amount of the displacement member is detected;
Determination means for determining whether or not the detection value output from the detection means matches a threshold value for determination corresponding to a preset pressure set in advance;
When the determination result of the determination means is affirmative determination, in a pressure detection control device comprising control means for controlling the operation mode of the control target to be a predetermined operation mode set in advance,
Storage means for storing a detection value corresponding to an actual displacement amount of the displacement member under the pressure condition of the set pressure detected in advance by the detection means as the determination threshold;
The pressure detection control apparatus, wherein the determination means determines whether or not a detection value output from the detection means at the time of the pressure fluctuation matches a determination threshold value stored in the storage means. The control target is a drive source that causes the pressure fluctuation by causing fluid to flow during driving, and the control unit drives the drive source when the determination result of the determination unit is affirmative. The pressure detection control device according to claim 2, wherein the pressure detection control device is configured to be stopped. The displacement member is integrated with a flexible member that is welded to a pressure chamber in which a fluid flows with a pressure fluctuation as the driving source is driven so as to bend and deform with a pressure fluctuation in the pressure chamber. The pressure detection control device according to claim 3, wherein the detection unit is configured to capture a change in a relative distance from the displacement member that is displaced in accordance with a bending deformation of the flexible member as a pressure change. The pressure detection control device according to claim 4, further comprising an urging member that urges the flexible member in a direction to suppress bending deformation of the flexible member based on pressure fluctuation in the pressure chamber. The storage means stores a numerical value individually corresponding to an actual displacement amount when the displacement member is displaced under the pressure condition of the set pressure as the determination threshold value. The pressure detection control apparatus as described in any one. The numerical value individually corresponding to a predetermined displacement amount range including an actual displacement amount when the displacement member is displaced under the pressure condition of the set pressure is stored as the determination threshold value in the storage means. The pressure detection control device according to claim 5. A liquid ejecting head capable of ejecting a liquid, a liquid container that supplies the liquid to the liquid ejecting head based on the pressure of the pressurized fluid when the pressurized liquid is supplied, and the pressure applied to the liquid container. A liquid ejecting apparatus comprising: a driving source that is driven to supply a pressurized fluid while changing the pressure thereof; and the pressure detection control device according to any one of claims 2 to 7.

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