JP3849657B2 - pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a pump that draws fluid inside and discharges it outside.
[0002]
[Prior art]
  Among a wide variety of pumps, as shown in FIG. 5, there is a Keiri rotary pump which is a kind of rotary pump. The pump 70 has a drum 73 in which an air supply port (suction hole) 71 and a discharge port (discharge hole) 72 are formed. The pump 70 is located above the drum 73 between the air supply port 71 and the discharge port 72. A rotor (rotor) 74 is rotatably provided in contact with the inner surface. Two rotor blades 76a and 76b connected to the rotor 74 by a spring 75 in the diameter direction are slidably arranged in the diameter direction. When the rotor 74 rotates, the two blade plates 76a are arranged. , 76b rotate while contacting the inner surface of the drum 73 by the force of the spring and the centrifugal force. When the rotor 74 rotates in such a structure, the water is put in a region 77 a communicating with the air supply port 71 among the regions surrounded by the two blades 76 a and 76 b, the rotor 74 and the drum 73. Or air is inhaled. Then, as the rotation of the rotor 74 proceeds, the sucked water or air proceeds to the region 77c communicating with the discharge port 72 via the region 77b not communicating with the air supply port 71 and the discharge port 72, and the discharge port Water or air is discharged from 72 (see Non-Patent Document 1).
[0003]
[Non-Patent Document 1]
  Machine Reissue Committee Editor, “New Machine Element”, Science and Engineering, 1977, 10th Edition, p. 203 (27.13 Keiri rotary pump 1)
[0004]
[Problems to be solved by the invention]
  However, in the Keiri rotary pump 70 of Non-Patent Document 1, the structure is complicated and has a large number of parts, so that the manufacturing cost is high. When the spring 75 is damaged, the blades 76a and 76b accompanying the rotation of the rotor 74 are used. The movement in the diameter direction is not performed smoothly, and it is difficult to suck water or air from the air supply port 71, which causes a problem of pump failure.
[0005]
  Therefore, an object of the present invention is to provide a pump that is unlikely to cause a pump failure and that reduces the manufacturing cost with a simple structure.
[0006]
[Means for Solving the Problems]
  The pump according to claim 1 of the present invention has a cavity inside, and a first through hole for sucking fluid into the cavity and a second through hole for discharging fluid from the cavity are formed. A case, a rotor rotatable in the cavity, and a state in which two end faces are slidably supported in a direction transverse to the rotor so as to always contact the wall surface of the cavity. An elastic plate-like member that can rotate with the rotorA sliding friction coefficient between the rotor and the elastic plate-like member is smaller than a sliding friction coefficient between the rotor and the elastic plate-like member, and the sliding members are arranged on both sides so as to sandwich the elastic plate-like member WhenIt is characterized by having.
[0007]
  According to such a configuration, when the rotor rotates, the two end faces are hollow due to the sliding of the elastic plate member in the direction crossing the rotor and the expansion and contraction of the elastic plate member in the same direction. Since the fluid is always brought into contact with the wall surface, the fluid can be sucked into the cavity from the first through-hole, and the sucked fluid can be discharged from the second through-hole with a spring instead of the elastic plate member. Compared with the known technique using two urged plates, the structure is simple and failure is reduced. In addition, since no spring or the like is used, the number of parts is reduced and the manufacturing cost is reduced.
  Further, according to such a configuration, the elastic plate-like member sandwiched between the sliding members slides smoothly with respect to the rotor together with the sliding members, so that the rotation of the rotor is compared with the case where no sliding member is arranged. Accordingly, the movement of the elastic plate-like member with respect to the rotor becomes smooth, and the reliability of the pump is improved.
[0008]
  The pump according to claim 2, wherein the rotor is rotatable while constantly or intermittently contacting a specific position on the wall surface of the cavity, and the rotor is in contact with the specific position on the wall surface. The cavity is divided into a plurality of regions each surrounded by the case, the rotor, and the elastic plate member, and the first through hole and the second through hole are in different regions. It is characterized by that.
[0009]
  According to such a configuration, when the rotor is in contact with a specific position on the wall surface, the first through hole and the second through hole formed in the case are respectively separated by the case, the rotor, and the elastic plate member. Since it exists in the different area | regions of the enclosed several area | region, the operation | movement which attracts | sucks a fluid in a cavity via a 1st through-hole, and discharges a fluid from a cavity via a 2nd through-hole is performed In this case, the efficiency of sucking and discharging the fluid is improved, and the pump capacity is improved.
[0010]
[0011]
[0012]
  Claim3The pump described in (1) is characterized in that a length of the sliding member in a direction crossing the rotor is shorter than that of the elastic plate member.
[0013]
  According to such a configuration, since the elastic plate-like member protrudes from both ends of the sliding member, the elastic plate-like member protruding from the rotor is not bent excessively. Therefore, the elastic plate-like member is easily slid with respect to the rotation of the rotor, and an excessive rotational torque is prevented and the sealing performance between the elastic plate-like member and the case is stabilized. Can do.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
[0015]
[Entire printer configuration]
  FIG. 1 is a side view showing an overall configuration of an ink jet printer to which a pump according to the present embodiment is applied. An ink jet printer 1 shown in FIG. 1 is a color ink jet printer having four ink jet heads 2. The printer 1 is provided with a paper feed unit 3 on the left side in the drawing and a paper discharge unit 4 on the right side in the drawing.
[0016]
  A paper conveyance path that flows from the paper supply unit 3 toward the paper discharge unit 4 is formed inside the printer. A pair of feed rollers 5 for sandwiching and transporting a sheet as a recording medium is disposed immediately downstream of the sheet feeding unit 3. The pair of feed rollers 5 feed the paper from the left to the right (conveying direction) in the drawing. In the middle part of the sheet conveyance path, two belt rollers 6 and 7 and an endless conveyance belt 8 wound around the rollers 6 and 7 are arranged. The outer peripheral surface (conveying surface) of the conveying belt 8 is subjected to silicon treatment, and while the sheet conveyed by the pair of feed rollers 5 is held on the conveying surface on the conveying belt 8 by its adhesive force, The belt roller 6 can be driven toward the downstream side (right side). A pressing member 9 is disposed at a position opposite to the belt roller 6 with respect to the sheet conveyance path. The pressing member 9 is used to press the sheet on the conveying belt 8 against the conveying surface of the conveying belt 8 so that the sheet on the conveying belt 8 does not float from the conveying surface so as to securely adhere to the conveying surface.
[0017]
  A peeling mechanism 10 is provided on the right side of the conveying belt 8 in the drawing, and the paper adhered to the conveying surface of the conveying belt 8 is peeled off from the conveying surface and sent to the paper discharge unit 4 on the right side. It is configured as follows.
[0018]
  In a region surrounded by the conveyance belt 8, a substantially rectangular parallelepiped shape (same as the conveyance belt 8) that supports the inkjet head 2 from the inner peripheral side by contacting the position opposite to the inkjet head 2, that is, the upper lower surface of the conveyance belt 8. Guide member 11 having a width of a certain degree) is arranged.
[0019]
  The four inkjet heads 2 are provided side by side along the paper transport direction corresponding to four color inks (magenta, yellow, cyan, and black). That is, the printer 1 is a line type printer. The inkjet head 2 is formed in an elongated rectangular shape having a longitudinal direction perpendicular to the paper conveyance direction in plan view, and a head body 18 (a flow path unit in which an ink flow path including a pressure chamber is formed at a lower end thereof, and a pressure And an actuator for applying pressure to the ink in the chamber. On the bottom surface of the head body 18, a large number of discharge nozzles having a small diameter for discharging ink downward are formed side by side.
[0020]
  The inkjet head 2 is disposed so that a small amount of a gap is formed between the lower surface of the inkjet head 2 and the conveyance surface of the conveyance belt 8, and a sheet conveyance path is formed in the gap portion. With this configuration, the paper transported on the transport belt 8 sequentially passes immediately below the head main body 18 of the four inkjet heads 2, and the ink of each color is ejected from the discharge nozzles toward the upper surface (printing surface) of the paper. By discharging, a desired color image can be formed.
[0021]
[Ink supply configuration to inkjet head]
  A configuration for supplying ink to the inkjet head 2 in the inkjet printer 1 will be described with reference to FIG.
  As shown in FIG. 2, an ink tank 20 is provided at an appropriate position in the printer 1 in order to supply ink of different colors to each inkjet head 2. The ink-jet head 2 and the ink tank 20 that are located apart from each other are connected by a pump 30 and a flexible tube 13 connected to the pump 30. Thus, an ink supply path (ink flow path) from the ink tank 20 to the inkjet head 2 is configured. Although only one ink tank 20 and one pump 30 are shown in FIG. 2, four ink tanks 20 are actually provided corresponding to the number of inkjet heads 2.
[0022]
  As shown in FIG. 2, the ink tank 20 includes an ink bag 22 inside a synthetic resin housing 21. The ink bag 22 contains degassed ink. The ink bag 22 has a resin spout that seals its opening, and this spout includes a cap 23 made of silicon rubber or butyl rubber. The ink bag 22 is composed of a pouch film formed by thermocompression bonding of a plurality of flexible films. In this pouch film, a polypropylene layer is formed on the innermost side, a polyester layer as a base material in order toward the outer side, an aluminum foil layer as a gas barrier layer laid on the polyester layer, and for improving the strength of the film Nylon layer is laminated in multiple layers.
[0023]
  The cap 23 can pass through a hollow needle 25 which will be described later, and when the ink in the ink tank 20 runs out, the hollow needle 25 can be removed from the cap 23 so that the entire ink tank 20 can be replaced. It has become.
[0024]
  The head main body 18 of the inkjet head 2 described above includes the cylindrical member 14 on the surface on the opposite side of the bottom surface on which the discharge nozzles are formed on one end in the longitudinal direction. One end of the tube 13 connected to the pump 30 is connected to the cylindrical member 14 so that the ink from the ink tank 20 is guided to the ink flow path inside the head body 18 and discharged from the discharge nozzle. It is configured. The tube 13 is formed in a cylindrical shape and has sufficient flexibility since it is made of an elastomer.
[0025]
[Pump configuration]
  Next, the configuration of the pump 30 will be described with reference to FIGS.
[0026]
  The pump 30 shown in FIG. 2 includes a cylindrical case 31, and an end surface is formed in the axial direction. Therefore, the cavity 32 exists in the case 31. An opening 33 is formed on one end surface of the case 31 so that a rotation shaft 43 of the rotor 40 described later can be fitted therein. A suction hole (first through hole) 31 a for sucking ink from the ink tank 20 into the cavity 32 of the pump 30 is formed on the side surface of the case 31 at a position facing the cap 23 of the ink tank 20. A metal hollow needle 25 having a cylindrical shape is directly connected to the suction hole 31a. The end of the hollow needle 25 on the ink tank 20 side is cut obliquely and thus has a sharp shape. As shown in FIG. 2, the hollow needle 25 directly connected to the suction hole 31 a is horizontally penetrated through the cap 23 of the ink tank 20 and forms an ink flow path between the ink tank 20 and the pump 30. Then, the ink in the ink bag 22 of the ink tank 20 is sucked from the suction hole 31 a into the cavity 32 of the pump 30 through the hollow needle 25.
[0027]
  Further, a discharge hole (second discharge port) for discharging ink from the inside of the cavity 32 to the ink jet head 2 side at a position rotated approximately 90 ° in the clockwise direction in FIG. 2 through-holes) 31b are formed. A filter storage portion 35 connected to one of the tubes 13 connected to the tubular member 14 of the head body 18 is connected to the discharge hole 31b. A communication hole is formed inside the filter housing part 35 so that the discharge hole 31b to the tube 13 face in the vertical direction. The communication hole constitutes a part of the ink flow path from the ink tank 20 to the inkjet head 2. Further, a substantially middle portion of the communication hole is expanded in the horizontal direction, and the filter 36 is disposed there so that the filter surface is horizontal.
[0028]
  The filter 36 is a mesh filter, and can filter the ink supplied from the ink tank 20 to the inkjet head 2 side. Accordingly, rubber bags generated by inserting / removing the hollow needle 25 into / from the cap 23 can be captured by the filter 36 and removed from the ink. As a result, for example, it is not necessary to provide a special filter structure on the ink tank 20 side, so that the ink tank can be simplified.
[0029]
  In addition, by arranging the filter 36 horizontally, the buoyancy of the bubbles with respect to the bubbles mixed in the ink when the ink is introduced from the state where the cavity 32 of the pump 30 is empty (when the ink is initially introduced) or the like. Since a relatively large force is applied by superimposing a liquid feeding force of the pump 30 described later, a configuration in which bubbles easily pass through the filter 36 is achieved. Therefore, it is less likely that a large amount of air bubbles stays upstream of the filter 36 and the ink supply to the inkjet head 2 is interrupted. Further, by forming the discharge hole 31b vertically above the case 31, the bubbles mixed in the cavity 32 at the initial introduction of the ink are smoothly discharged without countering the buoyancy. High discharge is obtained.
[0030]
  As shown in FIG. 2, a rotor (rotor) 40 is provided in the case 31 of the pump 30 so as to be rotatable at a fixed position. The rotor 40 has a cylindrical shape, and has a thickness such that both end surfaces in the axial direction are in contact with both end wall surfaces of the cavity 32 (inner end surfaces on the case 31). A cylindrical rotating shaft 43 is formed on one end face of the rotor 40 so as to protrude in the axial direction of the rotor 40, and is fitted into an opening 33 formed on one end face of the case 31. Yes. A gear (not shown) in which a part of the outer periphery always contacts is arranged on a part of the side surface of the rotating shaft 43, and the rotor 40 is rotated by the driving device (not shown) to rotate the rotor 40. Rotate through.
[0031]
  A through portion 41 is formed on the side surface of the rotor 40 in the diameter direction. In the state in which two sliding members 51a and 51b, which will be described later, and the partition member 50 are arranged so as to overlap with each other, the two sliding members 51a and 51b and the partition member 50 are formed in the penetrating portion 41. It is formed in a shape having a minimal gap that can move along the inner surface of 41.
[0032]
  As shown in FIG. 2, a partition member (elastic plate member) 50 made of an EPDM (ethylene / propylene / diene terpolymer) type synthetic rubber and a partition member 50 are sandwiched between the through portions 41 of the rotor 40. Two sliding members 51 a and 51 b arranged are arranged and traverse through the center of the rotor 40. Further, both end portions of the partition member 50 and the sliding members 51 a and 51 b in the longitudinal direction (a direction crossing the rotor 40) are arranged so as to protrude from the side surface of the rotor 40. In addition, since the partition member 50 is an elastic member, it can expand and contract in the longitudinal direction. The sliding members 51a and 51b are made of POM (polyoxymethylene) resin.
[0033]
  The partition member 50 has a plate shape having a rectangular planar shape, and has a length such that both end surfaces in the longitudinal direction are in contact with the inner peripheral surface of the case 31 (the wall surface of the cavity 32 in the case 31). Moreover, the partition member 50 has a thickness larger than one sliding member. By the partition member 50 having such a shape, the cavity 32 in the case 31 is always partitioned into two regions.
[0034]
  The two sliding members 51a and 51b have substantially the same shape as the partition member 50 described above, and the difference is that the length in the longitudinal direction is shorter than that of the partition member 50 and the thickness is thin. Further, since the sliding members 51a and 51b are made of resin, the sliding friction coefficient with respect to the through portion 41 of the sliding members 51a and 51b is smaller than the sliding friction coefficient with respect to the through portion 41 of the partition member 50. Therefore, the partition member 50 disposed between the sliding members 51a and 51b and disposed in the penetrating portion 41 can smoothly move on the inner surface of the penetrating portion 41 in the direction crossing the rotor 40 together with the sliding members 51a and 51b. . Therefore, compared with the case where the sliding members 51a and 51b are not disposed, the movement of the partition member 50 with respect to the rotor 40 accompanying the rotation of the rotor 40 becomes smooth, and the reliability as the pump 30 is improved.
[0035]
  Further, since the length of the sliding members 51a and 51b in the longitudinal direction is shorter than that of the partition member 50, when the rotor 40 is rotated by a driving device (not shown), both end surfaces of the sliding members 51a and 51b in the longitudinal direction are the case. The contact between the inner peripheral surface of the partition member 50 and the inner peripheral surface of the case 31 may be excessively bent due to friction between both end surfaces in the longitudinal direction of the partition member 50 and the inner peripheral surface of the case 31. Can be suppressed at both ends in the longitudinal direction of the sliding members 51 a and 51 b, so that both end portions of the partition member 50 are bent between the side surface of the rotor 40 and the inner peripheral surface of the case 31. Can be prevented. Therefore, excessive rotation torque is not generated when the rotor 40 rotates, and the contact between the both end portions of the partition member 50 and the inner peripheral surface of the case 31 can be stabilized. The sealability of the region can also be stabilized.
[0036]
  Further, a cutout portion 42 that is partially flat is formed on the side surface of the rotor 40 so as not to overlap the through portion 41. The notch 42 is located in a region where the suction hole 31a and the discharge hole 31b exist in the cavity 32 partitioned by the partition member 50 as shown in FIG. The discharge hole 31b is in communication with each other and forms an ink flow path in the pump 30.
[0037]
  3B, the rotor 40 is in a position where the side surface of the rotor 40 in which the notch 42 is not formed and the upper left part (specific position) of the inner peripheral surface of the case 31 are in contact with each other. Has been placed. Therefore, when the rotor 40 is rotated, the flow path from the suction hole 31a to the discharge hole 31b can be closed, and the flow path resistance from the suction hole 31a to the discharge hole 31b can be changed.
[0038]
[Ink supply operation during printing]
  Next, an ink supply operation at the time of printing with the inkjet head 2 in the inkjet printer 1 will be described.
[0039]
  When printing a desired image by ejecting ink droplets from the inkjet head 2 onto the paper transported by the transport belt 8, negative pressure is generated in the head body 18 by ejecting ink from the ejection nozzles of the head body 18. The ink jet head 2 sucks ink from the ink bag 22 of the ink tank 20 by the suction force using the negative pressure and the capillary phenomenon of the discharge nozzle.
[0040]
  Therefore, the pump that forms a part of the ink flow path between the ink jet head 2 and the ink tank 20 when the ink jet head 2 is sucking ink is divided as shown in FIGS. 2 and 3A. The rotation of the rotor 40 is stopped so that the notch 42 of the rotor 40 is located in a region where the suction hole 31a and the discharge hole 31b exist in the cavity 32 partitioned by the member 50.
[0041]
  That is, a gap is formed between the rotor 40 and the inner peripheral surface of the case 31 by the notch portion 42 of the rotor 40, and the gap causes the ink in the pump 30 to communicate with the suction hole 31a and the discharge hole 31b. Thus, the ink flow path of the ink tank 20 is secured from the ink jet head 2, and ink is supplied to the ink jet head 2. Further, the flow path resistance in the pump 30 from the suction hole 31 a to the discharge hole 31 b becomes low, and the ink tank 20 and the inkjet head 2 are connected in the pump 30 with low resistance. Therefore, necessary ink is naturally supplied from the ink tank 20 to the inkjet head 2 via the pump 30 in accordance with the ejection of ink from the inkjet head 2 during printing.
[0042]
[Pump operation during purge]
  Next, the pump operation during purge in the inkjet printer 1 will be described.
[0043]
  The operation of the pump 30 when purging bubbles mixed in the ink, such as when the ink tank 20 is replaced, is performed by first rotating the gear from the state of the rotor 40 shown in FIG. The rotor 40 is rotated. The pump 30 can forcibly send ink only by rotating the rotor 40. That is, when the rotor 40 is rotated in the direction of the arrow as shown in FIG. 3B, the side surface of the rotor 40 where the notch 42 is not formed and the inner peripheral surface of the case 31 come into contact with each other, and the exhaust is discharged from the suction hole 31a. The flow path to the hole 31b is closed and partitioned into a region communicating with the suction hole 31a, a region communicating with the discharge hole 31b, and a region not communicating with the suction hole 31a and the discharge hole 31b. As the rotor 40 rotates in the direction of the arrow as shown in FIG. 3C, the area communicating with the suction hole 31a becomes larger, and negative pressure is generated in the area so that ink is sucked from the ink tank 20. Will be. On the other hand, the area communicating with the discharge hole 31b becomes smaller as the rotor 40 rotates, and the ink existing in the area is forcibly fed from the discharge hole 31b to the inkjet head 2 side.
[0044]
  Further, as the rotor 40 rotates, the partition member 50 and the sliding members 51a and 51b arranged in the penetrating portion 41 of the rotor 40 are changed from the state shown in FIG. 3B to the penetrating portion as shown in FIG. It slides on the inner surface of 41 and moves in a direction across the rotor 40. That is, by the rotation of the rotor 40, a force that pushes downward in the direction across the rotor 40 caused by the contact between the upper end surface in the longitudinal direction of the partition member 50 shown in FIG. 3B and the inner peripheral surface of the case 31, The force that pushes upward in the direction crossing the rotor 40 generated by the contact between the lower end surface of the partition member 50 in the longitudinal direction and the inner peripheral surface of the case 31 is larger, and the partition member 50 and the sliding members 51a and 51b become the rotor. Move downward in the direction across 40. When the partition member 50 is moved, the sliding members 51a and 51b can smoothly move the partition member 50 in order to smoothly slide the inner surface of the penetrating portion 41.
[0045]
  Further, since the partition member 50 moves while expanding and contracting in the longitudinal direction as the rotor 40 rotates, both end surfaces of the partition member 50 are always in contact with the inner peripheral surface of the case 31. By such movement and expansion / contraction of the partition member 50 accompanying the rotation of the rotor 40, it becomes possible to generate a negative pressure in the area communicating with the suction hole 31a, and the ink existing in the area communicating with the discharge hole 31b is discharged. It becomes possible to discharge from the hole 31b.
[0046]
  In this way, the rotor 40 is rotated while the side surface of the rotor 40 not formed with the notch 42 is in contact with the inner peripheral surface of the case 31 so that the flow path from the suction hole 31a to the discharge hole 31b is closed. Then, the ink in the ink tank 20 is forcibly sucked into the pump 30 from the suction hole 31a and discharged from the discharge hole 31b, and the ink is moved to the inkjet head 2 side through the tube 13 connected to the discharge hole 31b. It is possible to forcibly send the liquid. Therefore, bubbles mixed in the ink or bubbles mixed in the ink from the tube 13 connected to the discharge hole 31b of the pump 30 can be purged together with the ink.
[0047]
  Further, the air bubbles mixed in the ink are sent to the ink jet head 2 side together with the ink by the liquid feeding force of the pump 30 that sucks the ink from the ink tank 20 and discharges the ink to the ink jet head 2 side. Air bubbles do not stay in the ink flow path connecting the ink tank 20 and are removed.
[0048]
  In addition, when the rotor 40 is in a position in contact with a specific position of the wall surface of the cavity 32 in the case 31, the suction hole 31a and the discharge hole 31b are not always in communication even when the rotor 40 rotates, that is, Since the flow resistance between the two is kept high, the liquid feeding capacity of the pump 30 does not decrease during the purge.
[0049]
  Further, in order to improve the ink feeding capability at the time of purging of the pump 30 applied to the inkjet printer 1, that is, the pump capability, for example, as a modification of the pump 30 of the present embodiment, a pump 60 shown below is used. It is possible to apply.
[0050]
[Pump variants]
  FIGS. 4A and 4B are diagrams showing an operation state of a modified example of the pump, and FIGS. 4A and 4B are views showing the progress of the rotation state of the rotor of the pump at the time of purge. The configuration other than the pump 30 of the inkjet printer 1 described above is substantially the same. However, since the pump 60 is for purging, it is formed so as to bypass the pump 60 when printing on paper with the inkjet head 2. Ink is supplied from the ink tank 20 to the inkjet head 2 via an ink flow path (indicated by a chain line in FIG. 2) 19. A valve (not shown) is provided at both ends of the ink flow path 19 so that the valve is closed when the pump 60 is in operation, and the valve is opened when the pump 60 is not in operation. Except for this point, the description is omitted because it is similar to the ink jet printer 1 described above. Moreover, about the thing similar to the pump 30, the same code | symbol is shown and description is abbreviate | omitted.
[0051]
  4 is provided with a case 31 having a suction hole 31a, a discharge hole 31b, and an opening 33 as in the case of the pump 30 described above. The cavity 32 in the case 31 is provided with a rotor 61 that can be rotated at a fixed position as in the pump 30 described above. However, the side surface of the rotor 61 is not formed with a notch 42, which is described above. This is a different point from the pump 30. Other than that, the rotary shaft 43 of the rotor 40, the penetrating part 41, the sliding members 51a and 51b, the partition member 50, the filter housing part 35 connected to the discharge hole 31b, the hollow needle 25 directly connected to the suction hole 31a, etc. Since it is the same as that described above, the same reference numerals are used.
[0052]
  The rotor 61 of the pump 60 is arranged such that its side surface is in contact with a specific position on the inner peripheral surface of the case 31, and the side surface of the rotor 61 and the inner peripheral surface of the case 31 are always maintained even when the rotor 61 rotates. In contact. Therefore, as shown in FIG. 4A, different areas among the three areas in which the suction hole 31 a and the discharge hole 31 b formed in the case 31 are respectively surrounded by the case 31, the rotor 61, and the partition member 50. Exists.
[0053]
  Further, when the rotor 61 of the pump 60 rotates, the above-described cutout portion 42 is not formed on the side surface thereof, so that the contact between the inner peripheral surface of the case 31 and the side surface of the rotor 61 is not intermittent. That is, since no gap is formed for communication between the suction hole 31a and the discharge hole 31b, ink is sucked into the cavity 32 through the suction hole 31a, and the ink is discharged from the cavity 32 through the discharge hole 31b. Its pumping ability is improved.
[0054]
[Pump operation during purge]
  Next, the pump operation at the time of purging with the inkjet head 2 in the pump 60 will be described below. During printing, the rotation of the rotor 61 of the pump 60 is stopped. As described above, the ink from the ink tank 20 is supplied to the inkjet head 2 through the ink flow path 19 formed in FIG. Yes.
[0055]
  The pump 60 can forcibly send ink only by rotating the rotor 61. That is, by rotating the rotor 61 shown in FIG. 4A in the direction of the arrow, the area communicating with the suction hole 31a becomes larger as shown in FIG. 4B, and negative pressure is generated in the area. Ink is sucked from the ink tank 20. On the other hand, the area communicating with the discharge hole 31b becomes smaller as the rotor 61 rotates, and the ink existing in the area is forcibly fed from the discharge hole 31b to the inkjet head 2 side. The movement of the partition member 50 and the sliding members 51a and 51b arranged in the penetrating part 41 accompanying the rotation of the rotor 61 is the same as the movement accompanying the rotation of the rotor 40 of the pump 30 described above.
[0056]
  Thus, the region communicating with the suction hole 31a and the region communicating with the discharge hole 31b are always closed by the contact between the side surface of the rotor 61 and the specific position of the wall surface of the cavity 32 in the case 31, so that the rotor 61 Even if the rotation continues, the suction hole 31a and the discharge hole 31b are always kept in communication. Therefore, the liquid feeding capacity of the pump 60 does not decrease during the purge, and the pump capacity can be improved as compared with the pump 30 described above.
[0057]
  As described above, when the rotors 40 and 61 of the pumps 30 and 60 are rotated, the sliding of the partition member 50 in the direction crossing the rotors 40 and 61 and the expansion and contraction of the partition member 50 itself in the same direction Since the two end faces always come into contact with the wall surface of the cavity 32, the fluid can be sucked into the cavity 32 from the suction hole 31a, and the sucked fluid can be discharged from the discharge hole 31b. Instead, the structure is simple and the number of failures is reduced as compared to a known technique using two plates biased by springs. In addition, since no spring or the like is used, the number of parts is reduced and the manufacturing cost is reduced.
[0058]
  Further, if the flow path from the suction hole 31a to the discharge hole 31b of the pumps 30 and 60 is closed, the rotors 40 and 61 are continuously rotated, so that the ink tank 20 can perform ink jetting without printing. Since the ink can be forcibly supplied to the head 2, bubbles staying in the inkjet head 2 can be purged together with the ink. Further, by controlling the increase / decrease in the number of rotations of the rotors 40 and 61, it is possible to increase / decrease the liquid feeding force and the liquid feeding amount of the ink fed to the ink jet head 2 side. In addition, since only the metal hollow needle 25 is interposed between the ink tank 20 and the pumps 30 and 60, bubbles are hardly mixed in the ink between the ink tank 20 and the pumps 30 and 60.
[0059]
  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made as long as they are described in the claims. For example, in the pump operation during purging, the side surfaces of the rotors 40 and 61 of the pumps 30 and 60 and the inner peripheral surface of the case 31 (the wall surface of the cavity in the case 31) are intermittently or continuously generated when the rotors 40 and 61 rotate. You may always have some gaps, without contacting. That is, of the two regions partitioned by the partition member 50 in the cavity 32 in the case 31 of the pumps 30 and 60, the case 31 of the pumps 30 and 60 in the region where the suction hole 31a and the discharge hole 31b are present. The flow path resistance from the suction hole 31a to the discharge hole 31b may be increased by bringing the inner peripheral surface and the side surfaces of the rotors 40 and 61 closer to each other. When the rotors 40 and 61 are rotated in such a state, the ink can be discharged from the discharge hole 31b while being absorbed from the suction hole 31a.
[0060]
  Further, the filter storage portion 35 may not be provided. Further, the sliding members 51a and 51b that sandwich the partition member 50 disposed in the through portion 41 of the rotors 40 and 61 may not be provided. Further, the partition member 50 may be a stack of a plurality of sheets. Furthermore, a coating agent as a sliding agent may be applied to the surface of the partition member 50 that comes into contact with the inner surface of the penetrating portion 41.
[0061]
  The material of the partition member 50 is not limited to EPDM, and may be composed of other synthetic rubbers such as SBR (styrene rubber), NBR (nitrile rubber), CR (chloroprene rubber). Further, the material of the sliding members 51a and 51b is not limited to POM resin, and may be made of other resin such as PC (polycarbonate) resin, polypropylene resin, or polyethylene resin.
[0062]
  Further, the present invention is not applied only to an ink jet printer, but can be applied to all devices that require a pump function for sucking fluid from the suction hole and discharging the fluid from the discharge hole. Further, the fluid sucked and discharged from the pump is not limited to ink, but may be other liquids or gases.
[0063]
【The invention's effect】
  As described above, according to the present invention, pump failure is less likely to occur due to the elastic plate-like member, and the manufacturing cost can be reduced because the structure is simple.
[Brief description of the drawings]
FIG. 1 is a side view showing an overall configuration of an ink jet printer to which a pump according to an embodiment of the present invention is applied.
FIG. 2 is a schematic diagram illustrating a configuration of an ink supply path of the inkjet printer illustrated in FIG.
FIGS. 3A and 3B are diagrams showing an operation state of a pump applied to the ink jet printer shown in FIG. 1, wherein FIG. 3A shows a pump state at the time of printing, and FIGS. 3B and 3C show a rotor of the pump at the time of purging. The progress of the rotation state is shown.
FIGS. 4A and 4B are diagrams showing an operation state of a modified example of the pump shown in FIG. 3, and FIGS. 4A and 4B are views showing the progress of the rotation state of the rotor of the pump at the time of purging. FIGS.
FIG. 5 is a schematic cross-sectional view of a pump that is a type of conventional rotary pump.
[Explanation of symbols]
  1 Inkjet printer
  2 Inkjet head
  20 Ink tank
  30, 60 pumps
  31 cases
  31a Suction hole (first through hole)
  31b Discharge hole (second through hole)
  32 cavity
  40, 61 rotor (rotor)
  50 Partition member (elastic plate member)
  51a, 51b Sliding member

Claims (3)

A case having a cavity therein, and a first through hole for sucking fluid into the cavity and a second through hole for discharging fluid from the cavity;
A rotor rotatable in the cavity;
An elastic plate-like member that is rotatable together with the rotor in a state in which two end faces are slidably supported in a direction transverse to the rotor so as to always contact the wall surface of the cavity ;
A sliding friction coefficient between the rotor and the elastic plate-like member is smaller than a sliding friction coefficient between the rotor and the elastic plate-like member, and sliding members arranged on both sides of the elastic plate-like member. A pump characterized by comprising. The rotor is rotatable while constantly or intermittently contacting a specific position on the wall surface of the cavity;
When the rotor is in contact with the specific position of the wall surface, the cavity is divided into a plurality of regions each surrounded by the case, the rotor, and the elastic plate member, and the first 2. The pump according to claim 1, wherein the first through hole and the second through hole exist in different regions. The pump according to claim 1 or 2 , wherein a length of the sliding member in a direction crossing the rotor is shorter than that of the elastic plate member.

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