JP4774799B2 - Container with liquid detection function - Google Patents

Description

  The present invention relates to a container having a liquid detection function (mainly an ink remaining amount detection function) applied to a liquid ejecting apparatus such as an ink jet recording apparatus.

  A typical example of a conventional liquid ejecting apparatus is an ink jet recording apparatus provided with an ink jet recording head for image recording. Other liquid ejecting apparatuses include, for example, an electrode material (conductive paste) used for electrode formation such as an apparatus provided with a color material ejecting head used for manufacturing a color filter such as a liquid crystal display, an organic EL display, and a surface emitting display (FED). ) An apparatus equipped with an ejection head, an apparatus equipped with a bioorganic matter ejection head used for biochip production, an apparatus equipped with a sample ejection head as a precision pipette, and the like.

  In an ink jet recording apparatus which is a typical example of a liquid ejecting apparatus, an ink jet recording head having a pressure generating means for pressurizing a pressure generating chamber and a nozzle opening for ejecting pressurized ink as ink droplets is mounted on a carriage. The ink in the ink container is continuously supplied to the recording head via the flow path, so that printing can be continued. The ink container is configured as a detachable cartridge that can be easily replaced by the user when the ink is consumed, for example.

  Conventionally, the ink consumption management method of the ink cartridge includes a method of managing the ink consumption by calculating the number of ink droplets ejected from the recording head and the amount of ink sucked by the maintenance by software, or an ink cartridge. There is a method of managing a point in time when a predetermined amount of ink is actually consumed by attaching an electrode for detecting a liquid level.

  However, the method of managing the ink consumption by calculating the number of ink droplet ejections and the amount of ink by software has the following problems. Some heads have variations in weight of ejected ink droplets. Although the weight variation of the ink droplets does not affect the image quality, the ink cartridge is filled with an amount of ink with a margin in consideration of the accumulation of errors in the ink consumption due to the variation. Therefore, depending on the individual, there is a problem that ink is left by the margin.

  On the other hand, the method for managing the point in time when ink is consumed by the electrode can detect the actual amount of ink, so that the remaining amount of ink can be managed with high reliability. However, since the detection of the ink level depends on the conductivity of the ink, there are disadvantages that the types of ink that can be detected are limited and the electrode sealing structure is complicated. In addition, as a material for the electrode, a noble metal having high conductivity and high corrosion resistance is usually used, which increases the manufacturing cost of the ink cartridge. Furthermore, since it is necessary to mount two electrodes, the number of manufacturing steps increases, resulting in an increase in manufacturing cost.

Therefore, an apparatus developed to solve the above problem is disclosed in Patent Document 1 as a piezoelectric device (herein referred to as a sensor unit). This sensor unit is caused by residual vibration (free vibration) of the vibration plate after forced vibration in the presence or absence of ink in the cavity facing the vibration plate on which the piezoelectric elements are stacked. The remaining amount of ink in the ink cartridge is monitored by utilizing the change in the resonance frequency of the residual vibration signal.
JP 2001-146030 A

  By the way, when using the sensor unit described in Patent Document 1, it is necessary to allow ink to freely enter the cavity facing the diaphragm, but the side where the piezoelectric element or the like, which is an electrical element, is arranged. In order to prevent the ink from entering, it is necessary to strictly seal between adjacent members when mounting.

  As the seal structure, a structure in which the sensor unit is directly bonded to the periphery of the opening of the container body, or a structure in which the module is attached to the container body through an O-ring after directly bonding to the periphery of the opening of the module is shown. However, since the sensor unit is bonded to the periphery of the opening in all cases, it is difficult to ensure the sealing property if there is a variation in dimensions. Further, when directly adhering to the periphery of the opening of the container main body or the periphery of the opening of the module, it is easily affected by the wave of ink or bubbles in the ink, and there is a concern that erroneous detection may occur.

  In consideration of the above circumstances, the present invention can easily and reliably perform sealing when the sensor unit is attached to the container main body without being greatly affected by the dimensional accuracy of parts, An object of the present invention is to provide a container having a liquid detection function having a structure that is not easily affected by bubbles.

(1) A container body having a liquid reservoir inside and having a delivery passage for delivering the stored liquid to the outside, and a sensor housing provided near the terminal end of the delivery channel and provided in the container body A liquid detection sensor unit mounted on the sensor housing portion, and adjacent to the sensor housing portion through a sensor receiving wall provided on the inner bottom portion of the sensor housing portion. In addition, an annular seal having elasticity that seals between the sensor chamber and the sensor receiving wall, and a buffer chamber interposed in series in the delivery passage by communicating with the upstream side and the downstream side of the delivery passage. By pressing the member and the sensor unit toward the sensor receiving wall, the seal member is crushed, and the seal member is necessary between the seal member and the sensor unit and the sensor receiving wall. Comprising a pressing spring for imparting only a surface pressure, and
The sensor unit has a sensor cavity for receiving a liquid to be detected, and the lower surface of the sensor cavity is opened to allow the liquid to be received, and the upper surface is closed with a diaphragm, and the upper surface of the diaphragm is A sensor chip having a configuration in which a piezoelectric element is arranged, a metal sensor base for mounting and fixing the sensor chip, and mounting and fixing the sensor base, and when the sensor unit is mounted in the sensor housing portion And a resin unit base whose lower surface faces the sensor receiving wall via the seal member,
The sensor base and the unit base are formed with a liquid pool space communicating with the sensor cavity, and the sensor receiving wall includes the liquid pool space and the buffer chamber inside the annular seal member. A communication channel is provided,
A cover member is placed on the upper side of the unit base so as to cover the sensor chip in a non-contact manner with the sensor chip and the sensor base.
The pressing spring is accommodated in a compressed state between a wall of the sensor accommodating portion facing the cover member and the cover member,
A container having a liquid detection function, wherein the pressing force of the pressing spring is applied only to the unit base via the cover member, avoiding the sensor chip and the sensor base.
(2) A container main body having a liquid reservoir inside and having a delivery passage for delivering the stored liquid to the outside, and a sensor housing provided in the container main body near the terminal end of the delivery flow path A liquid detection sensor unit mounted on the sensor housing portion, and adjacent to the sensor housing portion through a sensor receiving wall provided on the inner bottom portion of the sensor housing portion. In addition, an annular seal having elasticity that seals between the sensor chamber and the sensor receiving wall, and a buffer chamber interposed in series in the delivery passage by communicating with the upstream side and the downstream side of the delivery passage. By pressing the member and the sensor unit toward the sensor receiving wall, the seal member is crushed, and the seal member is necessary between the seal member and the sensor unit and the sensor receiving wall. Comprising a pressing spring for imparting only a surface pressure, and
The sensor unit has a sensor cavity for receiving a liquid to be detected, and the lower surface of the sensor cavity is opened to allow the liquid to be received, and the upper surface is closed with a diaphragm, and the upper surface of the diaphragm is A sensor chip having a configuration in which a piezoelectric element is arranged, a metal sensor base for mounting and fixing the sensor chip, and mounting and fixing the sensor base, and when the sensor unit is mounted in the sensor housing portion And a resin unit base whose lower surface faces the sensor receiving wall via the seal member,
The sensor base and the unit base are formed with a liquid pool space communicating with the sensor cavity, and the sensor receiving wall includes the liquid pool space and the buffer chamber inside the annular seal member. A communication channel is provided,
A cover member that covers the sensor chip and the sensor base in a non-contact manner with the unit base is disposed on the upper side of the unit base, and the cover member is screwed to the container body,
The pressing spring is interposed between the cover member and the unit base in a compressed state,
A container having a liquid detection function , wherein the pressing force of the pressing spring is applied only to the unit base, avoiding the sensor chip and the sensor base .
(3) A container having the liquid detection function according to ( 2 ),
A container having a liquid detection function, wherein the pressing spring is a plate spring, and the plate spring is formed integrally with a terminal plate that is electrically connected to an electrode of the sensor chip.

  According to the present invention, an annular seal member having elasticity is interposed between the sensor unit and the sensor receiving wall, and by pressing the sensor unit toward the sensor receiving wall with a pressing spring, the seal member is crushed, Since the space between the sensor unit and the sensor receiving wall is sealed, it is easier to assemble the sensor unit separately and then attach the sensor unit to the container body later than when using an adhesive. it can. Moreover, since the variation of the dimension between components can be absorbed with the elasticity of a sealing member, reliable sealing can be performed by simple assembly. In addition, since the liquid pool space sealed by the sealing member is secured in front of the sensor cavity (open side), the sensor cavity is not easily affected by ink waves or bubbles in the ink. In addition, since the pressing force by the pressing spring is applied directly to the unit base that faces the sensor receiving wall, the influence of this pressing force can be prevented from affecting the sensor base and sensor chip, and the detection accuracy Can be raised.

  According to the present invention, since the pressing spring is accommodated in the sensor accommodating portion in a compressed state, the assembly is completed only by incorporating the pressing spring into the sensor accommodating portion together with the sensor unit.

  According to the present invention, since the cover member is provided on the upper side of the unit base, the sensor chip and the sensor base can be protected. In addition, since the load of the pressing spring is applied to the unit base via the cover member, the degree of freedom in coupling the pressing spring and the unit base can be increased.

  According to the invention, since the cover member is disposed on the upper side of the unit base, the sensor chip and the sensor base can be protected. Moreover, since the cover member is screwed to the container body and the pressing spring is interposed between the cover member and the unit base in a compressed state, the pressing spring can be assembled in a compact manner.

  Further, according to the present invention, since the pressing spring is a leaf spring, and the leaf spring is integrally formed on the terminal plate connected to the electrode of the sensor chip, the assembly can be performed in a compact manner and the number of parts can be reduced. Can be reduced.

  Further, according to the present invention, a sensor base on which a sensor chip is mounted is incorporated from above into the unit base, and in this state, the upper surface and the upper surface of the two parts arranged side by side, that is, both upper surfaces of the sensor base and the unit base By simply sticking the adhesive film across, it is possible to simultaneously fix and seal between two parts (metal sensor base and resin unit base) made of different materials. Therefore, the assembly workability is very good. In addition, since only the adhesive film is pasted over the two parts, the parts can be sealed without being greatly affected by the dimensional accuracy of each part. In addition, for example, when the adhesive film is welded by heating and pressing with a mass production machine, the sealing performance can be improved only by controlling the temperature and pressure by the mass production machine, and stabilization during mass production can be achieved. . Furthermore, since the adhesive film that affects the sealing performance is easy to mount and space efficient, the sensor unit can be downsized.

  Further, according to the present invention, since the height of the film adhesion surface with respect to the unit base is set at a position lower than the height of the film adhesion surface with respect to the sensor base, the sensor base can be pressed with an adhesive film with a step, The fixing force of the sensor base to the unit base can be enhanced. In addition, mounting without backlash is possible.

  Further, according to the present invention, the liquid that has flowed from the upstream side through the delivery passage in the container body is supplied to the sensor cavity via the upstream side buffer chamber, the unit base, and the inlet side flow path of the sensor base. Since the sensor base and the unit base are configured to be discharged to the downstream side of the delivery passage via the outlet side flow path and the downstream buffer chamber, the liquid flows only to the sensor cavity, and the liquid is supplied to the sensor cavity. And erroneous detection due to the retention of bubbles can be prevented as much as possible.

  Hereinafter, an ink cartridge (liquid container) with a liquid detection function according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of an ink jet recording apparatus (liquid ejecting apparatus) in which the ink cartridge of this embodiment is used. In FIG. 1, reference numeral 1 denotes a carriage. The carriage 1 is guided by a guide member 4 via a timing belt 3 driven by a carriage motor 2 and is reciprocated in the axial direction of the platen 5. ing.

  An ink jet recording head 12 is mounted on the side of the carriage 1 that faces the recording paper 6, and an ink cartridge 100 that supplies ink to the recording head 12 is detachably mounted thereon.

  A cap member 13 is disposed at a home position (right side in the figure) which is a non-printing area of the recording apparatus. When the recording head 12 mounted on the carriage 1 is moved to the home position, the cap member 13 is The recording head 12 is pressed against the nozzle forming surface to form a sealed space with the nozzle forming surface. A pump unit 10 is disposed below the cap member 13 for applying a negative pressure to the sealed space formed by the cap member 13 to perform cleaning or the like.

  Further, in the vicinity of the printing area side of the cap member 13, a wiping means 11 having an elastic plate such as rubber is disposed so as to be able to advance and retreat in the horizontal direction with respect to the movement locus of the recording head 12. Is configured to be able to wipe off the nozzle forming surface of the recording head 12 as necessary when reciprocating toward the cap member 13 side.

  FIG. 2 is a perspective view illustrating a schematic configuration of the ink cartridge 100. The ink cartridge 100 includes a sensor unit 200 that is a main element that performs a liquid detection function.

  The ink cartridge 100 includes a resin cartridge case (container main body) 101 having an ink storage portion (not shown) therein, and a resin cover 102 mounted so as to cover the lower end surface of the cartridge case 101. The cover 102 is provided for protecting various sealing films attached to the lower end surface of the cartridge case 101. An ink delivery unit 103 projects from the lower end surface of the cartridge case 101, and a cover film 104 for protecting an ink delivery port (not shown) is attached to the lower end surface of the ink delivery unit 103.

  Further, a sensor housing recess (sensor housing portion) 110 for housing the sensor unit 200 is provided on the narrow side surface of the cartridge case 101, and the sensor unit 200 and the compression coil spring ( The pressure spring 300 is accommodated. The compression coil spring (hereinafter simply referred to as a spring) 300, which will be described later, presses the sensor unit 200 against the sensor receiving wall 120 (see FIGS. 4 and 5) at the inner bottom of the sensor housing recess 110 to seal the seal ring 270 (see FIG. 4 to FIG. 6) is crushed to ensure the sealing property between the sensor unit 200 and the cartridge case 101.

  The sensor housing recess 110 is open on the narrow side surface of the cartridge case 101, and the sensor unit 200 and the spring 300 are inserted through the opening on the side surface. The opening on the side surface of the sensor housing recess 110 is closed from the outside by a sealing cover 400 with a substrate 500 in a state where the sensor unit 200 and the spring 300 are housed inside.

  3 is a front view of a part in which the sensor unit 200 and the spring 300 are incorporated in the sensor housing recess 110, FIG. 4 is a cross-sectional view taken along arrows IV-IV in FIG. 3, and FIG. FIG. 6 is an enlarged view of a main part of FIG.

  A sensor receiving wall 120 for receiving the lower end of the sensor unit 200 is provided on the inner bottom of the sensor housing recess 110 of the cartridge case 101. The sensor receiving wall 120 is a portion where the sensor unit 200 is placed on a flat upper surface, and a seal ring (annular seal member) 270 at the lower end of the sensor unit 200 is pressed by the elastic force of the spring 300.

  Below the sensor receiving wall 120, a pair of upstream and downstream sensor buffer chambers 122 and 123 that are separated from each other in the left-right direction with a partition wall 127 interposed therebetween are provided. A pair of communication ports (flow paths) 132 and 133 are provided corresponding to the chambers 122 and 123. Although not shown, the cartridge case 101 is provided with a delivery channel for delivering the stored ink to the outside. The sensor unit is positioned near the end of the delivery channel (near the ink delivery port). 200 is arranged.

  In this case, the upstream sensor buffer chamber 122 is communicated with the upstream delivery passage via the communication hole 124 (not shown), and the downstream sensor buffer chamber 123 is connected to the communication hole 125 (also not shown). And communicated with a delivery passage on the downstream side near the ink delivery port. The lower surfaces of the sensor buffer chambers 122 and 123 are not sealed with a rigid wall but are opened, and the openings are covered with a resin sealing film 105.

  The sensor unit 200 includes a resin-made plate-like unit base 210 having a recess 211 on the upper surface, a metal-made sensor base 220 housed in the recess 211 on the upper surface of the unit base 210, and a sensor base 220. A sensor chip 230 placed and fixed on the upper surface, an adhesive film 240 for fixing the sensor base 220 and the unit base 210, a pair of terminal plates 250 disposed on the upper side of the unit base 210, and pressing of the terminal plates 250. The plate-shaped pressing cover (cover member) 260 that protects the sensor chip 230 and a rubber seal ring 270 disposed on the lower surface of the unit base 210 are configured.

  As shown in FIG. 6, the details of each component are as follows. The unit base 210 has a recess 211 into which the sensor base 220 fits in the center of the upper surface, and the upper surface on the outer side of the upper surface wall 214 around the recess 211. The mounting wall 215 is set one step higher than the wall 214. In addition, the bottom wall of the recess 211 is provided with an inlet-side channel 212 and an outlet-side channel 213 (liquid reservoir space) that are circular through holes. Further, the lower surface of the unit base 210 is provided with a convex portion 217 into which the seal ring 217 is fitted on the outer periphery, and the inlet side channel 212 and the outlet side channel 213 are located on the convex portion 217. The seal ring 217 is made of rubber ring packing and has an annular convex portion 271 having a semicircular cross section on the lower surface.

  The sensor base 220 is made of a metal plate made of stainless steel or the like having higher rigidity than resin for the purpose of improving the acoustic characteristics of the sensor. The sensor base 220 has an inlet-side channel 222 and an outlet-side channel 223 (a liquid storage space) formed of two through holes corresponding to the inlet-side channel 212 and the outlet-side channel 213 of the unit base 210. Yes.

  An adhesive layer 242 is formed on the upper surface of the sensor base 220 by, for example, attaching a double-sided adhesive film or applying an adhesive, and the sensor chip 230 is mounted and fixed on the adhesive layer 242. .

  The sensor chip 230 has a sensor cavity 232 that receives ink (liquid) to be detected. The lower surface of the sensor cavity 232 is opened to enable ink reception, and the upper surface is closed with a diaphragm 233. The piezoelectric element 234 is arranged on the upper surface of the diaphragm 233.

  More specifically, the sensor chip 230 includes a ceramic chip body 231 centered on a sensor cavity 232 having a circular opening, and a diaphragm that is laminated on the upper surface of the chip body 231 and constitutes the bottom wall of the sensor cavity 232. 233, a piezoelectric element 234 stacked on the vibration plate 233, and terminals 235 and 236 stacked on the chip body 231.

  The piezoelectric element 234 includes upper and lower electrode layers 234a and 234b connected to the terminals 235 and 236, and a piezoelectric layer 234c laminated between the upper and lower electrode layers 234a and 234b. It fulfills the function of determining the ink end based on the difference in electrical characteristics depending on the presence or absence of ink in the cavity 232. As a material of the piezoelectric layer 234c, lead zirconate titanate (PZT), lead lanthanum zirconate titanate (PLZT), a lead-free piezoelectric film that does not use lead, or the like can be used.

  The sensor chip 230 is integrally fixed to the sensor base 220 by the adhesive layer 242 by placing the lower surface of the chip main body 231 on the center of the upper surface of the sensor base 220, and simultaneously with the sensor base 220 by the adhesive layer 242. A space between the sensor chips 230 is sealed. The inlet-side channels 222 and 212 and the outlet-side channels 223 and 213 (liquid pool spaces) of the sensor base 220 and the unit base 210 communicate with the sensor cavity 232 of the sensor chip 230. With this configuration, the ink enters the sensor cavity 232 through the inlet-side channels 212 and 222 and is discharged from the sensor cavity 232 through the outlet-side channels 223 and 213.

  Thus, the metal sensor base 220 on which the sensor chip 230 is mounted is accommodated in the recess 211 on the upper surface of the unit base 210. The sensor base 220 and the unit base 210 are integrally bonded by covering the resin adhesive film 240 thereon.

  That is, the adhesive film 240 has an opening 241 at the center, and the sensor base 220 is covered from the recess 211 on the upper surface of the unit base 210 so as to cover the sensor base 220 from the center opening 241 to the sensor chip 230. Is exposed. Further, by bonding the inner peripheral side of the adhesive film 240 to the upper surface of the sensor base 220 via the adhesive layer 242 and bonding the outer peripheral side to the upper surface wall 214 around the recess 211 of the unit base 210, That is, by sticking the adhesive film 240 across the upper surfaces of the two components (the sensor base 220 and the unit base 210), the sensor base 220 and the unit base 210 are fixed to each other and sealed at the same time.

  In this case, the upper surface of the sensor base 220 protrudes above the recess 211 of the unit base 210, and the adhesive film 240 is at a position higher than the bonding position with respect to the upper wall 214 around the recess 211 of the unit base 210. The sensor base 220 is bonded to the upper surface. Thus, by setting the height of the film bonding surface with respect to the sensor base 220 to a position higher than the height of the film bonding surface with respect to the unit base 210, the sensor base 220 can be pressed with the adhesive film 240 with a step. In addition, the fixing force of the sensor base 220 to the unit base 210 can be enhanced. In addition, mounting without backlash is possible.

  Each terminal plate 250 includes a spring piece 252 projecting from a side edge of the middle portion in the longitudinal direction of the strip and a bent piece 254 formed at an end portion in the longitudinal direction of the strip. The unit base 210 is disposed on the upper surface of the mounting wall 215. Then, by placing the pressing cover 260 from above, it is sandwiched between the unit base 210 and the pressing cover 260, and in this state, each spring piece 252 is brought into contact with the terminals 235 and 236 on the upper surface of the sensor chip 230. Yes.

  The presser cover 260 is a flat plate that is placed on the upper surface of the mounting wall 215 of the unit base 210 while sandwiching the substrate portion 251 of the terminal plate 250. In order to avoid this, the recess 265 is provided. The pressing cover 260 is placed on the upper surface of the unit base 210 while pressing the terminal plate 250 from above, thereby protecting the sensor base 220 and the sensor chip 230 accommodated in the recess 211 on the upper surface of the unit base 210. Yes.

  The sensor unit 200 is configured as described above, and is housed in the sensor housing recess 110 of the cartridge case 100 together with the spring 300 in a compressed state. In the accommodated state, the spring 300 presses the holding cover 260 downward, and the seal ring 270 provided on the lower surface of the sensor unit 200 is pressed against the sensor receiving wall 120 in the sensor accommodating recess 110 while being crushed. Thereby, the sealing property between the sensor unit 200 and the cartridge case 101 is ensured. In this case, the pressing force of the spring 300 is transmitted to the unit base 210 through the pressing cover 260 so that it does not reach the sensor base 220 and the sensor chip 230 at all. That is, the spring 300 applies a pressing force only to the unit base 210 through a force transmission path that avoids the sensor base 220 and the sensor chip 230.

  As a result of such assembly, the upstream buffer chamber 122 in the cartridge case 101 enters the sensor unit 200 through the communication hole 132 of the sensor receiving wall 120 under a condition in which sealing performance is ensured. The downstream buffer chamber 123 in the cartridge case 101 is communicated with the outlet channels 213 and 223 in the sensor unit 200 through the communication hole 133 of the sensor receiving wall 120. The inlet-side channels 212 and 222, the sensor cavity 232, and the outlet-side channels 213 and 223 are interposed in series in the delivery channel in the cartridge case 101 so that they are arranged in this order from the upstream side.

  Here, the upstream flow path connected to the sensor cavity 232 includes the upstream buffer chamber 122 having a large cross section, the communication port 132, and the input flow paths 212 and 222 in the sensor unit 200 having a small flow section. An upstream narrow channel). Further, the downstream flow path connected to the sensor cavity 232 includes the downstream buffer chamber 123 having a large flow section, the communication port 133, and the output flow paths 213 and 223 (downstream) in the sensor unit 200 having a small flow section. Side narrow channel).

Next, the principle of ink detection by the sensor unit 200 will be described.
When the ink in the ink cartridge 101 is consumed, the stored ink is sent from the ink delivery unit 103 to the recording head 12 of the ink jet recording apparatus via the sensor cavity 232 of the sensor unit 200.

  At this time, the sensor cavity 232 is filled with ink when ink is sufficiently left in the ink cartridge 100. On the other hand, when the remaining amount of ink in the ink cartridge 100 decreases, no ink exists in the sensor cavity 232.

  Therefore, the sensor unit 200 detects a difference in acoustic impedance caused by the change in this state. Accordingly, it is possible to detect whether the ink is sufficiently remaining or whether the remaining amount is low due to consumption of a certain amount of ink.

  Specifically, when a voltage is applied to the piezoelectric element 234, the diaphragm 233 is deformed along with the deformation of the piezoelectric element 234. When the application of voltage is canceled after the piezoelectric element 234 is forcibly deformed, the flexural vibration remains on the diaphragm 233 for a while. This residual vibration is free vibration between the diaphragm 233 and the medium in the cavity 232. Therefore, by setting the voltage applied to the piezoelectric element 234 to a pulse waveform or a rectangular wave, the resonance state between the diaphragm 233 and the medium after the voltage is applied can be easily obtained.

  This residual vibration is vibration of the diaphragm 233 and is accompanied by deformation of the piezoelectric element 234. For this reason, the piezoelectric element 7 generates a counter electromotive force with the residual vibration. This counter electromotive force is detected outside via the terminal plate 250.

  Since the resonance frequency can be specified by the back electromotive force detected in this way, the presence or absence of ink in the ink cartridge 100 can be detected based on this resonance frequency.

According to the above embodiment, the seal ring 270 having elasticity is interposed between the sensor unit 200 and the sensor receiving wall 120, and the sensor unit 200 is pressed against the sensor receiving wall 120 by the spring 300, thereby sealing the sensor unit 200. Since the gap between the sensor unit 200 and the sensor receiving wall 120 is sealed while the ring 270 is crushed, an assembly procedure in which the sensor unit 200 is separately assembled in advance and the sensor unit 200 is attached to the cartridge case 101 later. Can be used, and the assembly at that time can be simplified compared to the case of using an adhesive.

  In addition, since the variation in dimensions between the sensor unit 200 and the sensor receiving wall 120 can be absorbed by the elasticity of the seal ring 270, reliable sealing can be performed by simple assembly. In addition, since the liquid pool space (the inlet side channels 212 and 222 and the outlet side channels 213 and 223) sealed by the seal ring 270 is secured in front of the sensor cavity 232 (open side), the wave of ink And is less susceptible to bubbles in the ink. In addition, the pressing force by the spring 300 is applied directly to the unit base 210 that faces the sensor receiving wall 120, though the pressing cover 260 is interposed therebetween. It is possible not to reach the sensor chip 230, and the detection accuracy can be increased.

  Further, since the spring 300 only needs to be accommodated while being compressed in the sensor accommodating portion 110, it can be easily incorporated together with the sensor unit 200.

  Further, since the pressing cover 260 is provided on the upper side of the unit base 210, the sensor chip 230 and the sensor base 210, which are important elements in terms of vibration characteristics, can be protected. Further, since the load of the spring 300 is applied to the unit base 210 via the presser cover 260, the coupling between the spring 300 and the unit base 210 can be freely determined, and the design is easy.

  In addition, the sensor base 220 on which the sensor chip 230 is mounted is incorporated into the unit base 210 from above, and in this state, the upper surface and the upper surface of the two parts arranged side by side, that is, both the upper surfaces of the sensor base 220 and the unit base 210. By simply sticking the adhesive film 240 across, it is possible to simultaneously fix and seal between two parts made of different materials (the sensor base 220 made of metal and the unit base 210 made of resin). Therefore, the assembly workability is very good. In addition, since the adhesive film 240 is only pasted over two parts, the parts can be sealed without being affected by the dimensional accuracy of each part. In addition, for example, when the adhesive film 240 is heated and pressurized by a mass production machine and is welded, the sealing performance can be improved only by controlling the temperature and pressure by the mass production machine, so that stabilization during mass production is achieved. Can do. Furthermore, since the adhesive film 240 that affects the sealing performance is easy to mount and has good space efficiency, the sensor unit 200 can be downsized.

  In addition, the inlet side channels 212 and 222 and the outlet side channels 213 and 223 with respect to the sensor cavity 232 are respectively formed in the sensor base 220 and the unit base 210, and the ink is supplied to the sensor cavity 232 through the inlet side channels 212 and 222. Since the ink flows into the sensor cavity 232 and the liquid or bubbles stay in the sensor cavity 232, the detection error is caused. Can be prevented.

  In addition, since the height of the adhesive surface of the adhesive film 240 with respect to the unit base 210 is set at a position lower than the height of the adhesive surface with respect to the sensor base 220, the sensor base 220 is pressed with the adhesive film 240 with a step. Thus, the fixing force of the sensor base 220 to the unit base 210 can be enhanced. In addition, mounting without backlash is possible.

  Further, the sensor unit 200 is arranged near the end of the delivery flow path in the cartridge case 101, and the inlet side flow paths 212 and 222, the sensor cavity 232, and the outlet side flow paths 213 and 223 of the sensor unit 200 are arranged upstream in this order. In other words, the remaining liquid amount in the ink cartridge 100 can be accurately detected.

  FIG. 7 shows a main configuration of another embodiment of the present invention. In this figure, the same components as those in the embodiment shown in FIGS. 1 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

  In this embodiment, a cover member 260B that covers the sensor chip 230 and the sensor base 210 without touching the unit base 210 is disposed on the upper side of the unit base 210. The cover member 260B is attached to the cartridge case 101 with a screw 701. It is fixed with. A plate spring (pressing spring) 259 for pressing the unit base 210 to crush the seal ring 270 is interposed between the cover member 260B and the unit base 210 in a compressed state.

  The leaf spring 259 in this case is formed integrally with each terminal plate 250, and it is sufficient that a predetermined pressing force is applied only to the unit base 210 at the stage of regular assembly. The terminal plate 250 is provided with a spring piece 252 that elastically contacts the terminals 235 and 236 (see FIG. 6) of the sensor chip 230. The spring force of the plate spring 259 exerts any force on the spring piece 252. It is formed at a position far away.

  As shown in the illustrated example, one end of the spring piece 259 may be inserted when the cover member 260B is formed, and the terminal plate 250 may be formed integrally with the cover member 260B. In this case, there is no need to separately support the terminal plate 250.

  Further, the leaf spring 259 may be prepared and provided completely separately from the terminal plate 250, or another pressing spring other than the leaf spring 259 may be provided if space is allowed.

  As described above, the cover member 260B is fixed to the cartridge case 101 with the screw 701, and the leaf spring 259 (pressing spring) is interposed between the cover member 260B and the unit base 210 in a compressed state. Can be assembled. Further, since the leaf spring 259 is formed integrally with the terminal plate 250 that is electrically connected to the terminals 235 and 236 of the sensor chip 230, it is possible to perform compact assembly and reduce the number of parts and reduce the number of assembly steps. it can.

1 is a perspective view illustrating a schematic configuration of an ink jet recording apparatus (liquid ejecting apparatus) in which an ink cartridge (container) according to an embodiment of the present invention is used. 1 is an exploded perspective view illustrating a schematic configuration of an ink cartridge according to an embodiment of the present invention. FIG. 4 is a front view of a portion where a sensor unit is assembled to an ink cartridge. FIG. 4 is a cross-sectional view taken along arrow IV-IV in FIG. 3. It is a VV arrow sectional view of Drawing 4. It is an enlarged view of the principal part of FIG. It is sectional drawing which shows the principal part structure of another embodiment of this invention.

Explanation of symbols

100 Ink cartridge 101 Cartridge case (container body)
110 Sensor housing recess (sensor housing)
120 sensor receiving wall 122 upstream sensor buffer chamber 123 downstream sensor buffer chamber 132,133 communication hole (flow path)
200 Sensor unit 210 Unit base 211 Recessed portion 212 Inlet side flow path (liquid pool space)
213 Outlet channel (Liquid pool space)
214 Upper surface wall 220 Sensor base 222 Inlet flow path (liquid pool space)
223 Outlet channel (Liquid pool space)
230 Sensor chip 232 Sensor cavity 233 Vibration plate 234 Piezoelectric element 235, 236 Terminal 240 Adhesive film 242 Adhesive layer 250 Terminal plate 259 Leaf spring (pressing spring)
260 Presser cover (cover member)
260B Cover member 270 Seal ring (annular seal member)
300 Spring (Pressing spring)
700 screws

Claims (3)

A container main body having a liquid storing portion inside and a delivery passage for sending the stored liquid to the outside;
A sensor accommodating portion provided in the container main body positioned near the end of the delivery flow path;
A sensor unit for liquid detection mounted in the sensor housing;
The delivery passage is provided on the container main body and adjacent to the sensor accommodation portion via a sensor receiving wall provided on the inner bottom of the sensor accommodation portion, and communicates with the upstream side and the downstream side of the delivery passage. A buffer chamber interposed in series,
An annular sealing member having elasticity for sealing between the sensor unit and the sensor receiving wall;
Pressing the sensor unit toward the sensor receiving wall to apply a surface pressure necessary for sealing between the seal member, the sensor unit, and the sensor receiving wall while crushing the seal member A spring,
The sensor unit has a sensor cavity for receiving a liquid to be detected, and the lower surface of the sensor cavity is opened to allow the liquid to be received, and the upper surface is closed with a diaphragm, and the upper surface of the diaphragm is A sensor chip having a configuration in which a piezoelectric element is arranged on,
A metal sensor base for mounting and fixing the sensor chip;
The sensor base is mounted and fixed, and has a resin unit base whose bottom surface faces the sensor receiving wall via the seal member when the sensor unit is mounted in the sensor housing portion. ,
The sensor base and the unit base are formed with a liquid pool space communicating with the sensor cavity, and the sensor receiving wall includes the liquid pool space and the buffer chamber inside the annular seal member. A communication channel is provided,
A cover member is placed on the upper side of the unit base so as to cover the sensor chip in a non-contact manner with the sensor chip and the sensor base.
The pressing spring is accommodated in a compressed state between a wall of the sensor accommodating portion facing the cover member and the cover member,
A container having a liquid detection function , wherein the pressing force of the pressing spring is applied only to the unit base via the cover member, avoiding the sensor chip and the sensor base . A container main body having a liquid storing portion inside and a delivery passage for sending the stored liquid to the outside;
A sensor accommodating portion provided in the container main body positioned near the end of the delivery flow path;
A sensor unit for liquid detection mounted in the sensor housing;
The delivery passage is provided on the container main body and adjacent to the sensor accommodation portion via a sensor receiving wall provided on the inner bottom of the sensor accommodation portion, and communicates with the upstream side and the downstream side of the delivery passage. A buffer chamber interposed in series,
An annular sealing member having elasticity for sealing between the sensor unit and the sensor receiving wall;
Pressing the sensor unit toward the sensor receiving wall to apply a surface pressure necessary for sealing between the seal member, the sensor unit, and the sensor receiving wall while crushing the seal member A spring,
The sensor unit has a sensor cavity for receiving a liquid to be detected, and the lower surface of the sensor cavity is opened to allow the liquid to be received, and the upper surface is closed with a diaphragm, and the upper surface of the diaphragm is A sensor chip having a configuration in which a piezoelectric element is arranged on,
A metal sensor base for mounting and fixing the sensor chip;
The sensor base is mounted and fixed, and has a resin unit base whose bottom surface faces the sensor receiving wall via the seal member when the sensor unit is mounted in the sensor housing portion. ,
The sensor base and the unit base are formed with a liquid pool space communicating with the sensor cavity, and the sensor receiving wall includes the liquid pool space and the buffer chamber inside the annular seal member. A communication channel is provided,
A cover member that covers the sensor chip and the sensor base in a non-contact manner with the unit base is disposed on the upper side of the unit base, and the cover member is screwed to the container body,
The pressing spring is interposed between the cover member and the unit base in a compressed state,
A container having a liquid detection function , wherein the pressing force of the pressing spring is applied only to the unit base, avoiding the sensor chip and the sensor base . A container having the liquid detection function according to claim 2 ,
A container having a liquid detection function, wherein the pressing spring is a plate spring, and the plate spring is formed integrally with a terminal plate that is electrically connected to an electrode of the sensor chip.

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