JP2008200995A - Bubble size determining device, maintenance device, and fluid ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bubble size determining device which can detect the size of a bubble present in a fluid flowing through a channel, and to provide a maintenance device, and a fluid ejection device. <P>SOLUTION: The bubble size determining device includes: an acute head portion 19a of a feeding needle 19, which is arranged at a vertical intermediate point of the feeding needle 19, for inhibiting a bubble B in ink from moving upward; a light emitting device 26 and a light receiving section 27 which are arranged at a vertical intermediate point of the feeding needle 19 and at predetermined locations on a downstream side of the needle head portion 19a, for detecting presence/absence of the bubble B; and a control device for determining whether or not the size of the bubble B is not smaller than a bubble critical size, based on the intensity of electric current input from the light receiving section 27. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bubble size determination device that determines the size of bubbles present in a fluid flowing in a flow path, a maintenance device that performs maintenance of a fluid ejection device, and a fluid that includes the maintenance device and the bubble size determination device The present invention relates to an injection device.

  Generally, an ink jet printer (hereinafter simply referred to as “printer”) is known as a fluid ejecting apparatus that ejects ink (fluid) from a nozzle of a recording head (fluid ejecting head) to a target. In such a printer, an ink cartridge (fluid storage means) for storing ink is detachably attached, and the recording head supplies paper (target) to the ink supplied from the ink cartridge via an ink supply path (flow path). ) Is executed by jetting the ink. Further, in order to reduce the ejection failure of the recording head ink during printing, in such a printer, cleaning for forcibly discharging the thickened ink or bubbles from the nozzles of the recording head is executed. .

That is, when air bubbles are present in the ink supply path that connects the ink cartridge and the recording head, the ink passes through the ink supply path from the ink cartridge side so as to pass between the inner wall surface of the ink supply path and the air bubbles. It will flow to the recording head side. For this reason, when the bubbles in the ink supply path become too large, a very narrow gap is formed between the inner wall surface of the ink supply path and the bubbles in the ink supply path. In some cases, it becomes difficult to supply ink. Therefore, in a recent printer, when a predetermined time has elapsed since the last cleaning was completed, the size of bubbles in the ink supply path can hinder the flow of ink to the recording head in the ink supply path. It was determined that the bubble size limit was reached, and cleaning (so-called timer cleaning) was performed (for example, Patent Document 1).
JP 2000-238295 A

  By the way, the predetermined time for executing the timer cleaning is a time set in advance at the time of manufacturing the printer, and is not a time in consideration of an actual use environment or a use situation for each printer. For this reason, even if the size of the bubbles present in the ink supply path is smaller than the bubble limit size, timer cleaning is not possible because the elapsed time since the previous cleaning has exceeded a predetermined time. This was executed as necessary, and ink was sometimes consumed wastefully.

  On the other hand, even if the size of the bubbles present in the ink supply path exceeds the bubble limit size, timer cleaning is executed when the elapsed time since the previous cleaning is less than a predetermined time. Sometimes it was not done. In such a case, there is a possibility that printing failure may occur as a result of not supplying sufficient ink into the recording head. Therefore, the printer described in Patent Document 1 has a problem in that cleaning cannot always be performed at an appropriate timing because the size of bubbles in the ink supply path cannot be accurately detected.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a bubble size determination device, a maintenance device, and a fluid ejection device that can detect the size of bubbles present in a fluid flowing in a flow path. It is to provide.

  In order to achieve the above object, the bubble size determination device of the present invention is a bubble size determination device that determines the size of bubbles existing in a fluid flowing in a flow path, and is disposed in the middle of the flow path. Restricting means for restricting upward movement of the bubbles in the fluid, and by the restricting means at a predetermined position in the middle of the flow path and below the position where the restricting means is disposed. A bubble detection means for detecting the presence or absence of a bubble in which movement is restricted, and when a bubble is detected by the bubble detection means, it is determined that the size of the bubble is greater than or equal to a preset bubble limit size Determination means. Note that the bubble size limit of bubbles in the present invention is the size of bubbles that can hinder the flow of fluid in the flow path, and not only indicates the size of one bubble but also an aggregate of a plurality of bubbles. It is the concept which shows the size of.

  In general, when bubbles exist in the fluid flowing in the flow path, the bubbles move upward due to buoyancy, but the upward movement is regulated by the regulating means in the flow path. Then, the size of the bubbles gradually increases downward from the regulating means. When a part of the bubbles whose size has increased (that is, the lower end portion) reaches a predetermined position set below the restricting means, smooth flow of the fluid in the flow path is caused by the increased bubbles. May be hindered. In this regard, in the present invention, when it is detected by the bubble detection means that there is a bubble at a predetermined position in the flow path, it is determined that the size of the bubble has exceeded the bubble limit size. Therefore, it is possible to detect the size of bubbles present in the fluid flowing in the flow path.

  In the bubble size determination device of the present invention, the flow path is a light-transmitting part in which at least a part of the flow path wall is formed of a light-transmitting material, and the bubble detecting means is the light-transmitting part. A light-emitting unit that emits light toward the fluid in the flow path via the light-transmitting light transmitted through the light-transmitting part and the fluid flowing in the flow path among the light emitted by the light-emitting part, or A light receiving portion that receives reflected light reflected at a boundary portion between the light transmitting portion and the fluid flowing in the flow path, and the bubble detecting means receives the light receiving portion. If the received light amount is outside the predetermined light reception amount range set in advance, it is detected that bubbles are present at the predetermined position in the flow path.

  According to this invention, the presence or absence of bubbles at a predetermined position in the flow path is detected according to the amount of light received by the light receiving unit. Therefore, it is determined whether or not the size of the bubbles in the flow path is equal to or larger than the bubble limit size based on the amount of light received by the light receiving unit.

In the bubble size determination device of the present invention, the flow path wall of the flow path is made of a rigid material.
According to this invention, unlike the case where the flow path wall is made of a flexible material, the displacement of the flow path wall is suppressed even when there is an external pressure. Therefore, erroneous detection of the presence or absence of bubbles at a predetermined position in the flow path by the bubble detection means is suppressed.

  In the bubble size determination apparatus of the present invention, bubble trapping means for trapping bubbles flowing downstream with the fluid in the channel is disposed downstream of the predetermined position in the channel.

  According to the present invention, when a predetermined position for detecting a bubble is set between the regulating unit and the bubble capturing unit, the bubbles present in the fluid in the flow path are between the regulating unit and the bubble capturing unit. It will gather near the predetermined position. Therefore, the presence / absence of bubbles at a predetermined position in the flow path is effectively detected by the bubble detection means.

  In the bubble size determination device of the present invention, the flow path has a tip located in the fluid storage means when the inside of the fluid storage means for storing the fluid communicates with the inside of the fluid ejection head for ejecting the fluid from the nozzle. The fluid supply section is to be configured, and the predetermined position is set in the fluid supply section.

According to this invention, before the bubbles existing in the fluid in the flow path are supplied into the fluid ejecting head, the presence or absence of the bubbles at a predetermined position in the flow path is detected by the bubble detection means.
The bubble size determination apparatus of the present invention includes a vibration unit that is driven to vibrate the flow path, and a detection unit that detects a resonance frequency when the flow path resonates based on the drive of the vibration means. Further, the determination unit determines that the bubble size is equal to or larger than the bubble limit size when the resonance frequency of the flow path detected by the detection unit is included in a preset frequency range. To do.

  According to this invention, the flow path is resonated by vibrating the flow path by driving the vibration means. When the resonance frequency (that is, the resonance frequency) is a value included in the range of the frequency region, it is determined that the size of the bubble located in the predetermined region in the flow path is equal to or larger than the bubble limit size. The

  A maintenance device according to the present invention is mounted on a fluid ejecting apparatus including a fluid ejecting head that ejects fluid from a nozzle, and includes a cleaning unit that performs cleaning for sucking and discharging the fluid from the nozzle of the fluid ejecting head. The apparatus further comprises permission means for permitting cleaning by the cleaning means when the determination means of the bubble size determination device determines that the size of the bubbles is equal to or larger than the bubble limit size.

  According to this invention, while the bubble size is less than the bubble limit size in the flow path, cleaning by the cleaning means is not permitted. Therefore, execution of cleaning at unnecessary timing is suppressed.

  The fluid ejecting apparatus of the present invention includes a fluid storing unit that stores a fluid, a fluid ejecting head that ejects a fluid from a nozzle, a flow path for supplying the fluid in the fluid storing unit into the fluid ejecting head, The air bubble size determination device and the maintenance device are provided.

  According to the present invention, since cleaning is performed at an appropriate timing, occurrence of ejection failure when the fluid is ejected by the fluid ejecting head is well suppressed.

(First embodiment)
Hereinafter, a first embodiment embodying a bubble size determination device, a maintenance device, and a fluid ejection device of the present invention will be described with reference to FIGS. In the following description of the present specification, when referring to “front-rear direction”, “left-right direction”, and “up-down direction”, the front-rear direction (sub-scanning direction) and the left-right direction (main scanning direction) indicated by arrows in FIG. ) And the vertical direction respectively.

  As shown in FIG. 1, an ink jet printer 11 as a fluid ejecting apparatus includes a frame 12 having a substantially rectangular box shape. A platen 13 is provided at the lower part in the frame 12 along the left-right direction which is the longitudinal direction thereof. On the platen 13, the paper P is fed from the rear side by a paper feed mechanism (not shown) based on driving of a paper feed motor 14 provided at the lower back of the frame 12.

  A guide shaft 15 is installed above the platen 13 in the frame 12 along the longitudinal direction of the platen 13. A carriage 16 is supported on the guide shaft 15 so as to be capable of reciprocating along the axial direction (left-right direction) of the guide shaft 15. That is, the carriage 16 is supported so as to be reciprocally movable along the longitudinal direction of the guide shaft 15 by inserting the guide shaft 15 through a support hole 16a formed penetrating in the left-right direction.

  A driving pulley 17a and a driven pulley 17b are rotatably supported at positions corresponding to both ends of the guide shaft 15 on the inner surface of the rear wall of the frame 12. An output shaft of a carriage motor 18 serving as a drive source for reciprocating the carriage 16 is connected to the drive pulley 17a, and an endless timing connected to the carriage 16 is connected between the pair of pulleys 17a and 17b. A belt 17 is hung. Accordingly, the carriage 16 is movable in the left-right direction via the endless timing belt 17 by the driving force of the carriage motor 18 while being guided by the guide shaft 15.

  Further, on the rear end side on the bottom wall portion of the carriage 16, as shown in FIGS. 2 and 3, as shown in FIGS. 2 and 3, a hollow structure supply needle (fluid supply portion) 19 formed with a conical sharp head 19 a is formed. The sharp head 19a is provided with a plurality of communication holes 19b (only two are shown in FIGS. 2 and 3) for communicating the inside and outside of the supply needle 19 with each other. Is formed. When the ink cartridge 20 serving as a fluid storage means for storing ink (fluid) is mounted on the carriage 16 in a detachable state from above, the sharp head 19 a of the supply needle 19 is attached to the lower surface of the ink cartridge 20. The ink cartridge 20 enters the ink cartridge 20 through the ink supply port 20 </ b> A formed on the side, and is positioned in the ink cartridge 20.

  A valve device 20B that functions as a check valve is provided in the ink supply port 20A of the ink cartridge 20. The valve device 20B has a bottomed cylindrical cylindrical portion 20C that has the same inner diameter as the ink supply port 20A and extends toward the inside of the ink cartridge 20, and the bottom of the cylindrical portion 20C (FIG. 2). In the center of the upper portion, a communication hole 20D that communicates the inside of the cylindrical portion 20C and the outside (that is, the inside of the ink cartridge 20) is formed penetratingly formed. The valve device 20B includes an annular rubber packing 21 disposed at the opening end of the ink supply port 20A, and a substantially disk disposed in the cylindrical portion 20C so as to be able to contact the packing 21 from above. And a coil spring 20F that applies a downward biasing force to the valve body 20E. Further, in the valve device 20B, a plurality (only two are shown in FIG. 2) of flow grooves 20G are formed on the radially outer side (outer peripheral surface) of the valve body 20E that slides in the vertical direction within the cylindrical portion 20C. It is formed along the vertical direction.

  When the ink cartridge 20 is not mounted on the carriage 16, the valve body 20 </ b> E applied with the downward urging force from the coil spring 20 </ b> F is brought into close contact with the rubber packing 21 from above, so that the ink cartridge 20. The ink inside is prevented from leaking outside through the ink supply port 20A. On the other hand, when the ink cartridge 20 is mounted on the carriage 16, the valve body 20E of the valve device 20B is pushed upward against the downward biasing force of the coil spring 20F by the supply needle 19 on the carriage 16. . The ink in the ink cartridge 20 flows into the supply needle 19 and flows out of the ink cartridge 20 through the communication hole 20D and the flow groove 20G.

  A recess 22 having a diameter larger than that of the proximal end of the supply needle 19 is formed in the bottom wall of the carriage 16 at a position corresponding to the position where the supply needle 19 is disposed. The filter 23 is accommodated. Further, a communication channel 24 extending downward from the bottom surface of the recess 22 is formed in the bottom wall portion of the carriage 16. Then, the ink in the ink cartridge 20 flows into the internal space 19c in the supply needle 19 through the valve device 20B in the opened state and the respective communication holes 19b of the sharp head 19a. After flowing downward in the internal space 19 c, it passes through the filter 23 and flows into the communication flow path 24.

  At this time, if air bubbles B are contained in the ink flowing from the ink cartridge 20 into the supply needle 19, the air bubbles B in the ink are captured by the filter 23 when the ink passes through the filter 23. In other words, the supply needle 19 accumulates in the internal space 19c. The bubbles B having a lighter specific gravity than the ink move upward due to buoyancy in the internal space 19c of the supply needle 19 and contact the sharp head 19a, thereby moving further upward (in this case, in the ink cartridge 20). Is regulated. Therefore, in the present embodiment, the regulating means is constituted by the sharp head 19 a of the supply needle 19.

  Further, the supply needle 19 of the present embodiment has a flow path wall made of a rigid material (for example, a metal such as stainless steel). Then, openings are formed in the middle of the supply needle 19 in the vertical direction at positions facing each other across the internal space 19c, and each of these openings is filled with a translucent material (eg, transparent glass). As a result, the translucent portions 25 are respectively formed. Each of these translucent portions 25 is sized such that the size (that is, the size) of the bubble B in the internal space 19 c of the supply needle 19 prevents the flow of ink from the ink cartridge 20 to the communication channel 24. In this case (that is, in a state indicated by a broken line in FIG. 3), the bubble B is formed at the same position in the vertical direction as the lower end side of the bubble B. In the present embodiment, the size of the bubble B indicated by the broken line in FIG. 3 is referred to as “bubble limit size”, and the position where each translucent portion 25 is formed in the vertical direction is defined as “predetermined size”. It shall be called “position”.

  Further, on the carriage 16, a light emitting device 26 that emits light toward the ink in the supply needle 19 through the right light transmitting portion 25 of each light transmitting portion 25, and the light emitting device 26 and the supply needle 19. And a light receiving portion 27 disposed at the opposite side of the surface. The light receiving unit 27 receives light transmitted through the ink in each of the light transmitting units 25 and the supply needle 19 among the light emitted from the light emitting device 26. In the present embodiment, in the light emitting device 26, the optical path of light emitted from the light emitting device 26 (arrow indicated by a broken line in FIG. 3) is the flow direction (vertical direction) of ink in the internal space 19c of the supply needle 19. It is configured to extend in the front-rear direction intersecting (orthogonal). Further, the light receiving portion 27 is formed so that the area of the light receiving portion is widened so that the light emitted from the light emitting device 26 can be received as much as possible.

  Further, as shown in FIG. 2, a recording head 28 as a fluid ejecting head is provided on the lower surface side of the carriage 16, and the recording head 28 is a substantially rectangular parallelepiped case head attached to the lower surface of the carriage 16. 29 and a head chip 30 attached to the lower surface of the case head 29. The case head 29 is formed with a case side channel 31 communicating with the communication channel 24 of the carriage 16 so as to extend in the vertical direction. In the case head 29, a valve unit 32 is provided at the lower end of the case side flow path 31.

  The head chip 30 is formed with a chip side flow path 33 that communicates with the case side flow path 31 of the case head 29, and the upper end communicates with the downstream end (front end) of the chip side flow path 33 and the lower end is the head chip. A nozzle 34 opening on the lower surface of 30 is formed. The ink in the ink cartridge 20 flows in the supply needle 19, the communication flow path 24 of the carriage 16, the case-side flow path 31 and the chip-side flow path 33 of the recording head 28 in order, and is supplied into the nozzle 34. The piezoelectric element 35 provided in the recording head 28 is driven (ejected) from the opening of the nozzle 34 by driving. Therefore, in the present embodiment, a flow path for supplying ink in the ink cartridge 20 into the recording head 28 is configured by the supply needle 19 and the communication flow path 24 of the carriage 16. A portion of the lower surface of the head chip 30 in which the opening of the nozzle 34 is formed is referred to as a “nozzle forming surface 28a”.

  In addition, a home position for positioning the carriage 16 when the recording head 28 is maintained is provided at the right end in the frame 12, that is, a non-printing area where the paper P does not reach. A maintenance device 36 that performs various maintenance operations is provided below the home position so that the ink ejection from the recording head 28 to the paper P is well maintained.

Next, the maintenance device 36 will be described below with reference to FIG.
As shown in FIG. 4, the maintenance device 36 has a cap 37 made of a synthetic resin having a bottomed square box shape with an open upper side that can contact the nozzle forming surface 28 a of the recording head 28 so as to surround each nozzle 34. It has. In the cap 37, a rectangular plate-shaped ink absorbing material 38 made of a flexible porous material is laid so as to cover the entire inner bottom surface of the cap 37. A rectangular frame-shaped sealing member 39 made of a flexible member such as rubber is provided on the entire upper surface of the cap 37.

  The cap 37 is connected to an elevating device 40 for raising and lowering the cap 37. Then, the cap 37 is lifted by the lifting device 40 in a state where the carriage 16 is moved to the home position of the non-printing region, so that the upper surface of the seal member 39 is in close contact with the nozzle forming surface 28a of the recording head 28. In addition, each nozzle 34 is surrounded and comes into contact with the recording head 28. The state in which the cap 37 is in contact with the recording head 28 so that the seal member 39 is in close contact with the nozzle forming surface 28a is also referred to as a “contact state” in the following. The upper surface of the absorbent material 38 is slightly separated from the nozzle forming surface 28a.

  A cylindrical discharge portion 41 having a discharge passage 41 a for discharging ink from the inside of the cap 37 to the outside of the cap 37 is provided on the lower surface of the cap 37 so as to extend downward. One end portion 42a (upstream end portion) of the discharge tube 42 made of a flexible material is connected to the discharge portion 41, and the other end portion 42b (downstream end portion) of the discharge tube 42 is discarded. It is inserted into the ink tank 43. Therefore, the cap 37 and the waste ink tank 43 are communicated with each other via the discharge tube 42. The ink that has flowed into the waste ink tank 43 is absorbed by the ink absorbing material 43 </ b> A housed in the waste ink tank 43.

  Further, a suction pump 44 (a tube pump in this embodiment) that is driven when a suction force is exerted in the cap 37 is disposed at an intermediate portion of the discharge tube 42. The suction pump 44 is driven in a contact state in which the seal member 39 of the cap 37 is in close contact with the nozzle forming surface 28a of the recording head 28 so as to surround each nozzle 34, thereby increasing the viscosity of the ink from within each nozzle 34. Is sucked together with bubbles or the like and discharged into the waste ink tank 43 via the cap 37 and the discharge tube 42, so-called cleaning is performed. Therefore, in the present embodiment, the cleaning means is configured by the cap 37, the discharge tube 42, and the suction pump 44.

Next, the light emitting device 26 will be described with reference to FIG.
As shown in FIG. 5, the light-emitting device 26 includes a light-emitting unit 45 (for example, an infrared laser or a light-emitting diode) that emits light based on control by a control device 50 described later, and the light-emitting unit 45 is formed on the supply needle 19. Light is emitted toward the translucent part 25. In the light emitting device 26, a split optical system 46 (for example, a half mirror) is disposed on the optical path of the light emitted from the light emitting unit 45. And the light which permeate | transmitted the division | segmentation optical system 46 among the lights light-emitted from the light emission part 45 is in the translucent part 25 of the supply needle | hook 19 in the state condensed by the condensing lens 47 arrange | positioned on the optical path. It is going to progress towards.

  On the other hand, the light reflected by the split optical system 46 out of the light emitted from the light emitting unit 45 is received by an in-device light receiving unit 48 (for example, a photodetector) arranged on the optical path, and the in-device light receiving unit 48. Is configured to output a current (electric signal) having a magnitude corresponding to the amount of received light to the control device 50.

Next, the electrical configuration of the ink jet printer 11 will be described with reference to FIG.
As shown in FIG. 6, the ink jet printer 11 includes a control device 50 that controls the entire printer 11. The input side interface of the control device 50 is electrically connected to the light receiving portion 27, the in-device light receiving portion 48 constituting the light emitting device 26, the operation portion 51 operated to give an opportunity to start cleaning, and the like. Yes. On the other hand, the output side interface of the control device 50 includes a paper feed motor 14, a carriage motor 18, a light emitting unit 45 of the light emitting device 26, each piezoelectric element 35, a lifting device 40, a suction pump 44, and a display having a display screen (not shown). The device 52 and the like are electrically connected. Then, the control device 50 responds to input signals from the light receiving units 27 and 48 and the operation unit 51, and the like, the paper feed motor 14, the carriage motor 18, the light emitting unit 45 of the light emitting device 26, each piezoelectric element 35, the lifting device. 40, the suction pump 44, the display device 52, and the like are controlled separately.

  In the control device 50, a CPU 53, a ROM 54, a RAM 55, a timer 56, an ASIC (Application Specific Integrated Circuit) 57, and the like are provided. In the ROM 54, various control programs (such as a bubble size determination process described later) for controlling the ink jet printer 11, various threshold values (a first light intensity threshold, a second light intensity threshold, etc. described later), and the like are stored in advance. Yes. The RAM 55 stores various information that can be appropriately rewritten while the ink jet printer 11 is being driven.

  Next, among the control processes executed by the control device 50 of the present embodiment, a bubble size determination process routine executed when detecting the bubble size in the supply needle 19 will be described based on the flowchart shown in FIG. To do.

  The control device 50 executes a bubble size determination process routine as a pre-process for executing printing. In this bubble size determination processing routine, the control device 50 executes a light emission amount adjustment process for adjusting the light amount of light emitted from the light emitting unit 45 of the light emitting device 26 to a predetermined light emission amount (step S10). That is, the control device 50 emits light from the light emitting unit 45 of the light emitting device 26 and detects the amount of light received by the in-device light receiving unit 48 based on the magnitude of the current input from the in-device light receiving unit 48. . Then, the control device 50 adjusts the magnitude of the current supplied to the light emitting unit 45 so that the received light amount received by the in-device light receiving unit 48 becomes a preset received light amount for adjustment, and the adjustment is completed. In this case, the process proceeds to step S11 described later.

  In step S <b> 11, the control device 50 detects the received light amount LT of the light received by the light receiving unit 27 based on the magnitude of the current input from the light receiving unit 27. When the bubble B does not exist in the predetermined region of the supply needle 19, the light reception amount LT of the light received by the light receiving unit 27 is a predetermined light reception amount range (the first light amount threshold value KLT1 or more and the second light amount). It falls within the range (below the threshold value KLT2).

  Then, the control device 50 determines whether or not the received light amount LT detected in step S11 is greater than or equal to a preset first light amount threshold value KLT1 (step S12). The first light quantity threshold value KLT1 is a value that becomes the lower limit of the above-described predetermined light reception amount range, and is set in advance through experiments, simulations, or the like. If the determination result in step S12 is negative (LT <KLT1), the control device 50 determines that the bubble B is present in a predetermined region of the supply needle 19, and the process proceeds to step S14 described later.

  On the other hand, when the determination result in step S12 is affirmative (LT ≧ KLT1), the control device 50 determines the second light amount in which the received light amount LT detected in step S11 is set to a value larger than the first light amount threshold value KLT1. It is determined whether or not the threshold value KLT2 or less (step S13). The second light amount threshold value KLT2 is a value that is the upper limit of the predetermined light reception amount range described above, and is set in advance by experiments, simulations, or the like. If the determination result in step S13 is negative (LT> KLT2), it is determined that the bubble B is present in a predetermined region of the supply needle 19, and the process proceeds to step S14 described later.

  That is, in the present embodiment, the control device 50 detects the presence / absence of bubbles at the predetermined position based on the magnitude of the received light amount LT received by the light receiving unit 27. When the presence of the bubble B is detected at the predetermined position, the control device 50 determines that the size of the bubble B in the supply needle 19 is equal to or larger than the size indicated by the broken line in FIG. 3 (hereinafter referred to as “bubble limit size”). Judge that there is. Therefore, in the present embodiment, the light emitting device 26, the light receiving unit 27, and the control device 50 function as bubble detection means. The control device 50 also functions as a determination unit.

  On the other hand, when the determination result in step S13 is affirmative (LT ≦ KLT2), the control device 50 determines that the bubble B is not present in the supply needle 19 or the size of the bubble B present in the supply needle 19 is a bubble. It is determined that the size is less than the limit size, and the bubble size determination processing routine is terminated. Therefore, in the present embodiment, the bubble size determination is performed by the restriction means (the sharp head 19a of the supply needle 19), the bubble detection means (the light emitting device 26, the light receiving unit 27, and the control device 50), and the determination means (the control device 50). The device is configured.

  In step S <b> 14, the control device 50 determines that the size of the bubble B in the supply needle 19 has become equal to or larger than the bubble limit size, and permits the execution of cleaning. Therefore, in the present embodiment, the control device 50 also functions as a permission unit. Then, the control device 50 controls the display device 52 so that a display for prompting the user to perform cleaning is displayed on the display screen of the display device 52 (step S15), and then the bubble size determination process. Exit the routine.

  When the user operates the operation unit 51 in this state, driving of the maintenance device 36 is started to perform manual cleaning. Then, since the flow rate of ink in the supply needle 19 is increased by driving the suction pump 44, the air bubbles B in the supply needle 19 forcibly pass through the filter 23 so as to be pushed by the ink, and in the recording head 28. Led to. The bubbles B introduced into the recording head 28 are discharged from the nozzles 34 into the cap 37 together with the ink. When the cleaning is completed, it is determined that the bubbles B have disappeared in the supply needle 19, and the display content of the display screen of the display device 52 is erased.

Therefore, in this embodiment, the following effects can be obtained.
(1) When the bubble detection means (the light emitting device 26, the light receiving unit 27, and the control device 50) detects that the bubble B is present at a predetermined position in the supply needle 19, the size of the bubble B is equal to or larger than the bubble limit size. It is determined that Therefore, the size of the bubble B existing in the ink flowing in the supply needle 19 can be detected.

  (2) When the received light amount LT received by the light receiving unit 27 is out of a predetermined received light amount range (a range that is not less than the first light amount threshold value KLT1 and not more than the second light amount threshold value KLT2), the supply needle (flow path) ) The presence of the bubble B is detected at a predetermined position in 19. Therefore, whether the size of the bubble B is equal to or larger than the bubble limit size can be detected based on the magnitude of the received light amount LT received by the light receiving unit 27.

  (3) Unlike the case where the peripheral wall (flow channel wall) of the supply needle (flow channel) 19 is made of a flexible material, the displacement of the peripheral wall of the supply needle 19 is suppressed even when there is an external pressure. Therefore, erroneous detection of the presence or absence of the bubble B at a predetermined position in the supply needle 19 by the bubble detection means (the light emitting device 26, the light receiving unit 27, and the control device 50) can be suppressed.

  (4) In the supply needle (flow path) 19, the air bubbles B contained in the ink (fluid) are likely to gather between the sharp head (regulating means) 19 a and the filter (bubble capturing means) 23. And a predetermined position is set at a position where it is easy to gather. Therefore, since it is possible to determine whether or not the size of the bubble B is equal to or larger than the bubble limit size at the portion where the bubble B is most likely to become large in the supply needle 19, the timing for executing the cleaning can be set to an optimum timing. .

  (5) Further, since the filter (bubble capturing means) 23 is disposed on the flow path constituted by the supply needle 19 and the communication flow path 24, the upstream side of the filter 23 is provided when cleaning is not performed. It is possible to suppress the bubbles B contained in the ink from being guided into the recording head 28.

  (6) Cleaning by the maintenance device 36 is not permitted while the size of the bubble B is less than the bubble limit size in the supply needle (flow path) 19. Therefore, it is possible to suppress the execution of cleaning at unnecessary timing.

  (7) In addition, when manual operation is performed when the operation unit 51 is operated on the display screen of the display device 52 in a state that prompts execution of cleaning, ink in the supply needle 19 The bubbles B contained in the ink are discharged through the nozzles 34 of the recording head (fluid ejecting head) 28. Therefore, it is possible to suppress the occurrence of ink ejection failure when the recording head 28 prints on the paper P.

  (8) In this embodiment, only when it is necessary to actually measure that the size of the bubble B in the supply needle 19 that is the flow path has reached the bubble limit size and to perform cleaning, A message that prompts cleaning is displayed on the display screen of the display device 52. Therefore, cleaning can be executed at an appropriate timing according to the actual use environment and use situation of the ink jet printer 11. Therefore, it is possible to suppress wasteful consumption of ink by performing cleaning at a timing at which cleaning does not need to be performed, and it is possible to suppress the occurrence of printing defects due to delay in the timing at which cleaning is performed.

  (9) The ink cartridge 20 may store deaerated ink (hereinafter referred to as “deaerated ink”). However, the degree of deaeration of the deaerated ink gradually changes according to the elapsed time after the ink cartridge 20 is mounted on the carriage 16. For this reason, the longer the elapsed time since the ink cartridge 20 is mounted on the carriage 16, the more easily the bubbles B accumulate in the supply needle 19, that is, the bubbles B become larger. Therefore, in so-called timer cleaning in which cleaning is performed at predetermined intervals set in advance, there is a possibility that cleaning cannot be performed at an appropriate timing. Therefore, in the present embodiment, the user is prompted to perform cleaning when the size of the bubble B in the supply needle 19 exceeds the bubble limit size. Therefore, it is possible to prompt the execution of cleaning at an optimal timing in consideration of the change in the degree of deaeration of the ink.

  (10) Further, each light transmitting portion 25 is formed only at a position where the light emitted from the light emitting device 26 passes toward the light receiving portion 27. Therefore, unlike the case where the entire supply needle 19 is made of a translucent material, the light receiving unit 27 receives light other than light emitted from the light emitting device 26 (hereinafter referred to as “unknown light”). This can be suppressed. Therefore, it is possible to suppress the occurrence of a detection error of the size of the bubble B due to the light receiving unit 27 receiving unknown light.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment, the arrangement positions of the light emitting device 26 and the light receiving unit 27 are different from those in the first embodiment. Therefore, in the following description, parts different from those of the first embodiment will be mainly described, and the same or corresponding member configurations as those of the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. Shall.

  As shown in FIG. 8, one translucent portion 25 </ b> A is provided in a midway portion in the vertical direction of the supply needle 19 of the present embodiment. Specifically, the translucent part 25A is disposed at a position where it comes into contact with the bubble B when the bubble B becomes larger than the bubble limit size (the size of the bubble indicated by the broken line in FIG. 8) in the supply needle 19. Has been. Further, the translucent part 25A is formed so that the width in the vertical direction is wider than each translucent part 25 of the first embodiment.

  In the present embodiment, the light emitting device 26 is arranged so that the optical path of the light emitted by the light emitting device 26 intersects the inner side surface of the translucent portion 25A at an acute angle, as indicated by the one-dot chain line arrow in FIG. It is installed. The light receiving unit 27 is in a state where the inner surface of the light transmitting unit 25 is in contact with the ink in the supply needle 19 (that is, the state where the inner surface of the light transmitting unit 25 is not in contact with the bubble B). The light is reflected at the boundary 60 between the inner surface of the translucent part 25 and the ink in the supply needle 19. That is, in the present embodiment, the light emitting device 26 and the light receiving unit 27 are respectively disposed on the rear side of the supply needle 19.

  When the size of the bubble B in the supply needle 19 becomes equal to or larger than the bubble limit size, the boundary portion 60 becomes a boundary between the inner surface of the translucent portion 25 and the bubble B having the bubble limit size. Therefore, among the light emitted from the light emitting device 26, the amount of light received by the light receiving portion 27 reflected by the boundary portion 60 is smaller than when the size of the bubble B is less than the bubble limit size. Therefore, when one of the above steps S12 and S13 is negative as a result of the execution of the bubble size determination processing routine by the control device 50, the bubble B in the supply needle 19 has exceeded the bubble limit size. On the display screen of the display device 52, a message for prompting cleaning is displayed.

In addition, you may change each said embodiment into another embodiment as follows.
In each of the above-described embodiments, in step S15 of the bubble size determination processing routine, cleaning may be automatically executed without displaying a message that prompts execution of cleaning on the display screen of the display device 52.

  In each of the above embodiments, the predetermined position for detecting the size of the bubble B may be provided in the communication channel 24 provided in the carriage 16. In this case, it is desirable that the filter 23 functions as a regulating unit, and the light emitting device 26 and the light receiving unit 27 are provided in the bottom wall portion of the carriage 16. Further, it is desirable that the light transmitting portions 25 and 25A are provided so as to constitute a part of the flow path wall of the communication flow path 24. In this case, a filter functioning as bubble trapping means may be provided separately from the filter 23 at the downstream end of the communication channel 24.

  In each of the above embodiments, the flow path may have a flow path wall formed of a flexible material. Even if comprised in this way, the effect of said (1), (2), (4)-(10) can be acquired.

In each of the above embodiments, the supply needle 19 may be entirely composed of a translucent material. Even if comprised in this way, the effect of said (1)-(9) can be acquired.
In each of the above embodiments, as shown in FIG. 9, the bubble size determination device includes an actuator 70 (for example, a piezoelectric element) that abuts on the supply needle 19 and vibrates the supply needle 19 in the front-rear direction, and a control device. 50, a drive circuit 71 that expands and contracts the actuator 70 based on a signal from the signal 50, and a detection device 72 as a detection means for detecting noise generated from the supply needle 19 during the expansion and contraction of the actuator 70. There may be. That is, when executing the bubble size determination process, the control device 50 outputs the pulse signal from the drive circuit 71 to cause the actuator 70 to expand and contract to vibrate the supply needle 19 and to detect the detection signal from the detection device 72. Based on the vibration, noise from the supply needle 19 is detected. That is, the actuator 70 and the drive circuit 71 constitute a vibration unit.

  Then, the control device 50 speeds up the expansion / contraction operation of the actuator 70 by gradually narrowing the pulse width of the pulse signal output from the drive circuit 71 to the actuator 70. When the noise from the supply needle 19 generated by vibrating the supply needle 19 exceeds a preset noise threshold, the control device 50 determines that the supply needle 19 has resonated, and The pulse period of the pulse signal output from the drive circuit 71 to the actuator 70 at the time is set to the resonance frequency of the supply needle 19. And the control apparatus 50 determines with the size of the bubble B in the supply needle | hook 19 having exceeded the bubble limit size, when the resonance frequency of the set supply needle | hook 19 is contained in the range of the preset frequency area | region. It will be. The frequency region is a region including the resonance frequency of the supply needle 19 when the size of the bubble B in the supply needle 19 is equal to or larger than the bubble limit size, and is set in advance by experiments, simulations, or the like. . When configured in this manner, it is possible to reliably determine whether or not the size of the bubble B in the supply needle 19 is equal to or larger than the bubble limit size by vibrating the supply needle 19. When the size of the bubble B is less than the bubble limit size, the resonance frequency of the supply needle 19 does not fall within the frequency range.

  In each of the above embodiments, it is determined whether or not one bubble B included in the ink in the supply needle 19 has reached the bubble limit size, but a plurality of bubbles B are included in the ink in the supply needle 19. Is included, a bubble size determination processing routine may be executed to determine whether or not the size of the aggregate of these bubbles B has reached the bubble limit size. That is, if the size of the aggregate composed of the plurality of bubbles B is increased, the smooth flow of the ink in the supply needle 19 may be hindered. Therefore, the size of the aggregate of the bubbles B becomes the bubble limit size. If it is determined that the cleaning has been performed, it is desirable to perform cleaning.

  In each of the above embodiments, the cap 37 may be configured so that waste ink is sucked from the recording head 28 when the suction pump 44 is driven in a state in which the cap 37 is in contact with the recording head 28. . For example, the cap 37 may be configured such that the upper portion thereof can contact the side surface of the recording head 28.

  In each of the above embodiments, the fluid ejecting apparatus has an overall shape in which the recording head 28 corresponds to the length of the paper P in the width direction (left-right direction) in a direction intersecting the transport direction (front-back direction) of the paper P. A so-called full line type printer may be embodied.

  In each of the above embodiments, the fluid ejecting apparatus is embodied in the ink jet printer 11. However, the present invention is not limited to this, and fluid other than ink (liquid or liquid in which particles of functional material are dispersed or mixed in the liquid) The present invention can also be embodied in a fluid ejecting apparatus that ejects or ejects a body). For example, a liquid material ejecting apparatus that ejects a liquid material that is dispersed or dissolved in materials such as electrode materials and color materials (pixel materials) used in the manufacture of liquid crystal displays, EL (electroluminescence) displays, and surface-emitting displays. Further, a liquid ejecting apparatus that ejects a bio-organic matter used for biochip manufacturing, or a liquid ejecting apparatus that ejects a liquid that is used as a precision pipette and serves as a sample may be used. In addition, transparent resin liquids such as UV curable resins to form liquid injection devices that inject lubricating oil onto precision machines such as watches and cameras, and micro hemispherical lenses (optical lenses) used in optical communication elements. May be a liquid ejecting apparatus that ejects liquid onto the substrate, or a liquid ejecting apparatus that ejects an etching solution such as acid or alkali to etch the substrate. The present invention can be applied to any one of these fluid ejecting apparatuses. In the present specification, the “fluid” includes, for example, a liquid (including an inorganic solvent, an organic solvent, a solution, a liquid resin, a liquid metal (metal melt), etc.), a liquid, and the like.

1 is a schematic perspective view of an ink jet printer according to a first embodiment. FIG. 3 is a schematic cross-sectional view of a carriage on which an ink cartridge is mounted. The schematic cross section which expanded a part of FIG. The schematic cross section explaining the outline of a maintenance device. The schematic diagram explaining the outline of a light-emitting device. 1 is a block circuit diagram showing an electrical configuration of an ink jet printer. The flowchart explaining a bubble size determination processing routine. FIG. 6 is a schematic cross-sectional view illustrating the arrangement of a light emitting device and a light receiving unit in a second embodiment. The schematic diagram of the bubble size determination apparatus in another embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Inkjet printer (fluid ejecting apparatus), 19 ... Supply needle (flow path, fluid supply part), 19a ... Sharp head (bubble size determination apparatus, regulation means), 20 ... Ink cartridge (fluid storage means), 23 DESCRIPTION OF SYMBOLS ... Filter (bubble capture means) 24 ... Communication flow path (flow path), 25, 25A ... Translucent part, 26 ... Light emitting device (bubble size determination apparatus, bubble detection means), 27 ... Light receiving part (bubble size determination apparatus) , Bubble detection means), 28 ... recording head (fluid ejection head), 34 ... nozzle, 36 ... maintenance device, 37 ... cap (cleaning means), 42 ... discharge tube (cleaning means), 44 ... suction pump (cleaning means) , 45 ... light emitting part, 48 ... light receiving part in the apparatus, 50 ... control device (bubble size determination device, bubble detection means, determination means, permission means), 60 ... boundary part, 70 ... Actuator (vibration means), 71 ... driving circuit (vibration means), 72 ... detector (detecting means), B ... bubbles, KLT1 ... first light amount threshold, KLT2 ... second light amount threshold, LT ... received light amount.

Claims (8)

A bubble size determination device for determining the size of bubbles present in a fluid flowing in a flow path,
A regulating means arranged in the middle of the flow path to regulate the upward movement of bubbles in the fluid;
Bubble detecting means for detecting the presence or absence of bubbles in a state where the upward movement is restricted by the restricting means at a predetermined position in the middle of the flow path and below the position where the restricting means is disposed; ,
A bubble size determination apparatus comprising: a determination unit that determines that the size of the bubble is equal to or larger than a predetermined bubble limit size when the bubble detection unit detects the bubble. The flow path is a translucent part in which at least a part of the flow path wall is formed of a translucent material,
The bubble detection means includes: a light emitting unit that emits light toward the fluid in the flow channel via the light transmitting unit; and the light emitted from the light emitting unit within the light transmitting unit and the flow channel. Transmitted light that has passed through the flowing fluid, or a light receiving portion that receives reflected light reflected at the boundary between the light transmitting portion and the fluid flowing in the flow path,
The bubble detection means detects that there is a bubble at the predetermined position in the flow path when the light reception amount received by the light receiving unit is outside a predetermined light reception amount range set in advance. Bubble size determination device. The bubble size determination device according to claim 1, wherein the flow path wall of the flow path is made of a rigid material. The bubble trapping means for trapping bubbles flowing downstream in the flow path together with the fluid is disposed downstream of the predetermined position in the flow path. The bubble size determination apparatus according to claim 1. The flow path includes a fluid supply unit whose tip is located in the fluid storage unit when the fluid storage unit that stores the fluid and the fluid ejection head that ejects the fluid from the nozzle communicate with each other. The bubble size determination device according to any one of claims 1 to 4, wherein the predetermined position is set in the fluid supply unit. Vibration means for driving the flow path to vibrate;
Detecting means for detecting the resonance frequency when the flow path resonates based on driving of the vibration means;
The said determination means determines that the size of the said bubble is more than the said bubble limit size, when the resonance frequency of the said flow path detected by the said detection means is contained in the range of the preset frequency area | region. The bubble size determination apparatus according to 1. A maintenance device that includes a cleaning unit that is mounted on a fluid ejecting apparatus that includes a fluid ejecting head that ejects fluid from a nozzle, and that performs cleaning for sucking and discharging the fluid from the nozzle of the fluid ejecting head,
A cleaning by the cleaning unit is performed when the determination unit of the bubble size determination device according to any one of claims 1 to 6 determines that the size of the bubble is equal to or larger than the bubble limit size. A maintenance device further comprising permission means for permission. Fluid storage means for storing fluid;
A fluid ejection head that ejects fluid from a nozzle;
A flow path for supplying fluid in the fluid storage means into the fluid ejecting head;
The bubble size determination device according to any one of claims 1 to 6,
A fluid ejection device comprising: the maintenance device according to claim 7.

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