JP4581464B2 - Gear pump and liquid injection device - Google Patents

Description

  The present invention relates to a gear pump and a liquid ejecting apparatus.

  Conventionally, the gear pump has an advantage that the structure is simpler than other pumps. An example of the gear pump is a gear pump 100 as shown in FIG. The gear pump 100 includes a drive gear 103 and a driven gear 104 in a housing chamber 102 in a housing 101. The opening of the housing chamber 102 of the housing 101 is sealed by a sealing plate (not shown), and the upper surfaces of the drive gear 103 and the driven gear 104 are slidably in contact with the sealing plate. When the drive gear 103 is rotated by the rotation of the drive shaft 105, the driven gear 104 is rotated by being driven by the drive gear 103 while being supported by the driven shaft 106. At this time, the fluid in the suction chamber 110 in the storage chamber 102 is confined to the tooth gaps of the gears 103 and 104 and the side surface 111 of the storage chamber 102 and sent out to the discharge chamber 112. Accordingly, since the fluid is successively sent to the discharge chamber 112 of the storage chamber 102 according to the rotation of the gears 103 and 104, the discharge chamber 112 has a higher pressure than the suction chamber 110.

At this time, if the gap between the drive gear 103 and the driven gear 104 and the sealing plate is large, the fluid flows backward from the high-pressure discharge chamber 112 to the low-pressure suction chamber 110 via the gap. For this reason, it is necessary to make the gap between the drive gear 103 and the driven gear 104 and the sealing plate as small as possible. In order to solve this problem, a gear pump has been proposed in which a leaf spring is provided between the bottom surface of the storage chamber 102 and the drive gear 103 and the driven gear 104 to press the gears against the sealing plate (for example, Patent Documents). 1).
JP-A-8-093657

  However, when the gears 103 and 104 are pressed against the sealing plate by the biasing force of the leaf spring, there is a problem that the friction torque or the viscous load torque when the gears slide on the sealing plate and the housing increases. .

An object of the present invention is to provide a gear pump and a liquid ejecting apparatus that can reduce a load during rotation of a gear while preventing a back flow of liquid.
Another object of the present invention is to provide a gear pump and a liquid ejecting apparatus capable of continuously ensuring the sealing performance of a storage chamber for storing a gear even when used for a long period of time.

Gear pump of the present invention is provided with a drive gear and a driven gear accommodating chamber provided in the housing, by rotation of the drive gear and the driven gear, in gear pump for deriving the fluid to the discharge side of the suction side, housed in the housing chamber A first seal that contacts at least a part of the driven gear and the driven gear and seals the opening of the storage chamber to prevent backflow of fluid from the discharge side to the suction side of the storage chamber Part, a second sealing part that seals the storage chamber in an airtight state outside the first sealing part, and the drive gear and the driven gear through the first sealing part. and biasing means for biasing the axial position, with a.

According to this, the 1st sealing part which seals the opening of a storage chamber is arrange | positioned in the state contact | abutted with at least one part of the drive gear and the driven gear. Accordingly, since the gap between the first sealing portion and each gear is reduced, the backflow of the fluid from the discharge side to the suction side of the storage chamber can be prevented, and the performance in the suction or discharge operation of the pump can be stabilized. . The second sealing portion seals the storage chamber in an airtight state from the outside of the first sealing portion. That is, by providing the second sealing portion outside the first sealing portion, a pressing force is applied only to the second sealing portion, and the pressing force against the first sealing portion and the second The pressing force against the sealing portion can be applied independently. For this reason, it can press with the pressing force of a respectively different magnitude | size, without considering mutual influences, such as deterioration of the material of each member. Therefore, the storage chamber can be more reliably sealed even when used for a long time. Further, when the accommodation chamber is firmly sealed with a fixing member such as a screw, even if a relatively large pressing force is applied to the second sealing portion, the pressing force is not applied to the first sealing portion. . For this reason, the load at the time of rotation of each gear can be reduced.
Further, the urging means urges the axial positions of the drive gear and the driven gear through the first sealing portion. For this reason, since the gap between the first sealing portion and each gear can be kept small by the biasing force of the biasing means, the backflow from the discharge side to the suction side of the storage chamber is more reliably performed. Can be prevented. Furthermore, since the biasing means biases the axial center position of each gear, the first sealing portion can maintain a flat surface without generating a warp due to the biasing. For this reason, it is possible to prevent the frictional load from increasing due to contact of the gears other than the protrusions with the first sealing portion. Further, since the gap between the first sealing portion and the gears other than the protrusions is determined only by the gear protrusion height, it is easy to manage this gap within a certain range, and suction is performed from the discharge side of the storage chamber. Backflow to the side is prevented.

In this gear pump, the second sealing portion is made of a flexible material.
According to this, the second sealing portion is made of a flexible material. For this reason, for example, the second sealing portion is elastically deformed by being pressed against the housing by a fastening force such as a bolt, and can seal the storage chamber in an airtight state.

  In this gear pump, at least one of a protrusion that contacts the first sealing portion and a protrusion that contacts the housing is formed on each side of the drive gear and the driven gear.

  According to this, at least one of the protrusion that contacts the first sealing portion and the protrusion that contacts the housing is formed on each side surface of the drive gear and the driven gear. For this reason, since the clearance gap between them becomes small by contact | abutting with each gearwheel and a 1st sealing part or a housing, the backflow of the fluid through the clearance gap is prevented. In addition, since the diameter of the contact portion is reduced by the contact between the first sealing portion or the housing and the protrusion, the friction load can be reduced when the contact is made with the same force. Moreover, the contact area between each gear and the first sealing portion or the housing can be reduced, and the viscous load applied when each gear rotates can be reduced.

In this gear pump, the second sealing portion is plate-shaped and has a size capable of covering the opening of the storage chamber.
According to this, the 2nd sealing part is plate-shaped, and is formed in the magnitude | size which can cover the opening of a storage chamber. That is, since the second sealing portion can have a simple structure, the manufacturing process and the assembly process can be reduced. Further, since the second sealing portion is plate-shaped, a molding error is unlikely to occur, and the reliability of the sealing action can be improved.

In this gear pump, the housing is formed with a pressure contact portion that is in pressure contact with the second sealing portion.
According to this, the housing is provided with a pressure contact portion that is in pressure contact with the second sealing portion. That is, for example, the second sealing portion is not pressed against the entire side surface of the housing, but is pressed against the pressing portion, so that the area to be pressed is reduced. For this reason, even with a small pressing force, the second sealing portion can be pressed against and brought into close contact with the pressure contact portion, and the storage chamber can be sealed in an airtight state.

  In this gear pump, a communication port that communicates from the outside of the housing to the accommodation chamber is provided, and the inflow of air from the outside of the housing to the accommodation chamber is allowed at the communication port only when the accommodation chamber is in a negative pressure state. A one-way valve was provided.

  According to this, the gear pump includes a communication port that communicates from the outside of the housing to the housing chamber, and a one-way valve that allows the inflow of air from the outside of the housing to the housing chamber only when the housing chamber is in a negative pressure state. . Therefore, when a negative pressure is generated in the storage chamber, the rapid flow of the fluid based on the pressure difference in the storage chamber can be reduced by flowing air into the storage chamber via the one-way valve. For this reason, generation | occurrence | production of the vibration of each gear by the rapid flow of a fluid and generation | occurrence | production of the noise by vibration can be prevented.

The liquid ejecting apparatus of the present invention includes the gear pump according to any one of the above.
According to this, since the liquid ejecting apparatus includes the gear pump according to any one of the above, even if the gear pump is used as the suction pump or the pressure pump, the load is small and the suction failure or the discharge failure is not caused. Can be prevented.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. FIG. 1 is a plan view illustrating an outline of a printer as a liquid ejecting apparatus according to the present embodiment.
As shown in FIG. 1, the printer 1 includes a frame 2 having a substantially rectangular parallelepiped shape. A platen 3 is disposed on the frame 2, and a recording sheet (not shown) as a target is fed onto the platen 3 by a paper feed mechanism (not shown).

  A guide member 4 is installed on the frame 2 so as to be parallel to the longitudinal direction of the platen 3. A carriage 5 that is movable along the guide member 4 is inserted into and supported by the guide member 4. A carriage motor 6 is attached to the frame 2, and the carriage motor 6 drives the carriage 5 via a timing belt 7 hung on a pair of pulleys PR. With this configuration, when the carriage motor 6 is driven, the driving force is transmitted to the carriage 5 via the timing belt 7, and the carriage 5 is supported by the guide member 4 and parallel to the longitudinal direction of the platen 3. It is designed to reciprocate.

  On the other hand, a recording head 8 as a liquid ejecting head is provided on the lower surface of the carriage (the surface facing the platen 3). The recording head 8 has a nozzle opening surface (not shown) on the lower surface facing the platen 3.

  As shown in FIG. 1, the frame 2 includes a cartridge case 9. An ink cartridge 10 as a liquid storage unit is detachably mounted in the cartridge case 9. In this embodiment, six ink cartridges 10 are provided, and each ink cartridge 10 stores various inks. The ink stored in each ink cartridge 10 is supplied to the recording head 8 via each tube T.

  The ink supplied to the recording head 8 is pressurized by a piezoelectric element (not shown) provided in the recording head 8 and discharged from the nozzles of the recording head 8 toward the recording paper as ink droplets.

  Further, as shown on the right side in FIG. 1, a cap 12 for sealing the nozzles of the recording head 8 when the printer 1 is in a non-printing state is provided in the non-printing area in the frame 2. The cap 12 is formed in a box shape having an upper surface opened, and the opening is disposed so as to face the nozzle opening surface of the recording head 8. The cap 12 is moved from the retracted position to the upper working position by a cap lifting mechanism (not shown), and seals the nozzle opening surface in order to prevent the nozzle from being dried.

  The cap 12 is formed with a suction port that allows the internal space in the cap 12 to communicate with the outside, and one end of the tube 13 is connected to the suction port. The other end of the tube 13 is connected to the pump unit 14. A waste ink tank 16 is connected to the pump unit 14 via a tube 15. Accordingly, when the pump unit 14 is driven when the cap 12 seals the nozzle opening surface, air or the like is discharged from the tube 13 and the pressure in the space formed by the cap 12 and the nozzle opening surface decreases. To do. As a result, so-called cleaning is performed in which thickened ink, bubbles, ink attached to the nozzle opening surface, and dust are discharged through the cap 12 in the nozzles of the recording head 8. The ink discharged into the cap 12 is sent to the waste ink tank 16.

  The pump unit 14 includes a drive motor, a drive mechanism, and a gear pump 20 (see FIG. 2) (not shown). When the drive motor is driven, the gear pump 20 is driven via the drive mechanism.

(Gear pump 20)
Next, the gear pump 20 will be described with reference to FIGS. 2 is an overall perspective view of the gear pump 20, and FIG. 3 is an exploded perspective view of the gear pump 20. As shown in FIG. 2, the gear pump 20 includes a housing 21, an upper sealing portion A, and a lower sealing portion B. A drive shaft 22 protrudes from the lower sealing portion B disposed on the bottom surface side of the housing 21. The drive shaft 22 is connected to the drive mechanism of the pump unit 14 and rotates by driving the drive motor.

(Housing 21, drive gear 35 and driven gear 40)
First, the housing 21 will be described with reference to FIGS. 4 and 5 are perspective views of the housing 21 and the drive gear 35 and the driven gear 40 accommodated in the housing 21. FIG. FIG. 6 is a plan view of the housing 21 that houses the drive gear 35 and the driven gear 40, and FIG. 7 is a bottom view of the housing 21.

  As shown in FIG. 4, the housing 21 is formed in a substantially rectangular parallelepiped shape, and a housing chamber 23 for housing the drive gear 35 and the driven gear 40 is recessed in the upper surface 21 a. The storage chamber 23 includes a first storage chamber 24 and a second storage chamber 25. As shown in FIG. 6, the first and second storage chambers 24, 25 are recessed in a circular shape, and partially overlap each other to form a storage chamber 23 as a whole. In addition, a suction part 26 and a discharge part 27 are recessed in the inner peripheral surface of the storage chamber 23 so as to be sandwiched between the first and second storage chambers 24 and 25, respectively.

Further, an inlet 28 is formed on the bottom surface of the storage chamber 23 on the suction part 26 side. The introduction port 28 penetrates through the housing 21 and opens at the bottom surface 21b as shown in FIG. The introduction port 28 opened on the bottom surface 21b side communicates with a groove portion 21c formed on the bottom surface 21b. Further, as shown in FIG. 6, a discharge port 29 is formed on the bottom surface of the storage chamber 23 on the discharge unit 27 side. The discharge port 29 penetrates the housing 21 and opens at the bottom surface of the recess 30 formed in the bottom surface 21b of the housing 21 as shown in FIG. The recess 30 is recessed in the bottom surface 21b in a substantially elliptical shape, avoiding the groove 21c formed in the bottom surface 21b. Further, as shown in FIG. 6, on the upper surface 21 a of the housing 21, a protrusion 21 d as a pressure contact portion is provided in an elliptical shape so as to surround the opening of the accommodation chamber 23. This protrusion 21d is formed at a position slightly spaced from the opening of the accommodation chamber 23 on the upper surface 21a.

  As shown in FIGS. 5 and 7, a first bearing portion 21 e is formed to protrude from the bottom surface of the recess 30 formed in the housing 21. The first bearing portion 21e is formed in a substantially fan shape, and a recess 21f is formed at the center thereof. As shown in FIG. 7, a first shaft hole 31 is formed through the bottom surface of the recess 21f. The first shaft hole 31 passes through the housing 21 and opens at the center position of the first storage chamber 24. The drive shaft 22 connected to the drive gear 35 is rotatably supported in the first shaft hole 31. The inner diameter of the first shaft hole 31 is larger than the outer diameter of the drive shaft 22, and when the drive shaft 22 is inserted into the first shaft hole 31, the first shaft hole 31 and the inner peripheral surface of the first shaft hole 31 are driven. A gap is provided between the outer peripheral surface of the shaft 22 (see FIG. 13).

  Further, as shown in FIG. 5, a second bearing portion 21g is formed so as to protrude from the bottom surface of the recess 30 formed in the housing 21 and adjacent to the first bearing portion 21e. The second bearing portion 21g is formed in a cylindrical shape, and a second shaft hole 32 is formed through the center of the second bearing portion 21g. The second shaft hole 32 passes through the housing 21 and opens at the center position of the second storage chamber 25. The second shaft hole 32 supports the driven shaft 44 (see FIG. 3) of the driven gear 40.

  Further, as shown in FIG. 4, cylindrical insertion portions 34 are formed at the four corners of the upper surface 21 a of the housing 21. Each fitting portion 34 has a screwing hole R1 into which the bolt BT shown in FIG. 3 can be screwed. The screwing hole R1 passes through the housing 21 and opens at the bottom surface 21b. Support plates SP are erected on both edges of the upper surface 21a.

  Next, the drive gear 35 and the driven gear 40 will be described. As shown in FIG. 5, the drive gear 35 is a spur gear and includes a first shaft hole 38 in the center thereof. The first shaft hole 38 is formed in a substantially rectangular shape in cross section, and is opened only on the lower surface 35b. As shown in FIG. 4, an annular protrusion 36 as a protrusion is formed on the upper surface 35 a of the drive gear 35. As shown in FIG. 5, an annular protrusion 37 as a protrusion is formed around the first shaft hole 38 on the lower surface 35 b of the drive gear 35. These annular protrusions 36 and 37 are formed to a height of 50 μm or less. The outer diameter of the annular protrusion 36 formed on the upper surface 35a is smaller than the outer diameter of the annular protrusion 37 formed on the lower surface 35b.

  The driven gear 40 that meshes with the drive gear 35 is a spur gear, and has a second shaft hole 43 at the center as shown in FIG. The second shaft hole 43 opens only on the lower surface 40b. Further, as shown in FIG. 4, an annular protrusion 41 as a protrusion is formed on the upper surface 40 a of the driven gear 40. Further, as shown in FIG. 5, an annular protrusion 42 as a protrusion is formed around the second shaft hole 43 on the lower surface 40 b. Each of the annular protrusions 41 and 42 is formed at a height of 50 μm or less, like the annular protrusions 36 and 37 formed on the drive gear 35. The outer diameter of the annular protrusion 41 formed on the upper surface 40a is smaller than the outer diameter of the annular protrusion 42 formed on the lower surface 40b.

  As shown in FIG. 6, the drive gear 35 and the driven gear 40 are accommodated in the first accommodation chamber 24 and the second accommodation chamber 25 in a state of being engaged with each other. In the first shaft hole 38 of the drive gear 35 housed in the first housing chamber 24, the drive shaft 22 that penetrates the first shaft hole 31 of the housing 21 from the lower surface 35 b side (see FIG. 3). Is inserted. Further, the second shaft hole 43 of the driven gear 40 accommodated in the second accommodation chamber 25 has a driven shaft 44 (FIG. 3) penetrating from the lower surface 40b side into the second shaft hole 32 of the housing 21. See) is inserted.

  As shown in FIG. 6, a suction chamber 45 and a discharge chamber 46 are formed in the storage chamber 23 by being partitioned into a drive gear 35 and a driven gear 40. The suction chamber 45 and the discharge chamber 46 are provided so as to sandwich the meshing positions of the drive gear 35 and the driven gear 40. One side of the suction chamber 45 is constituted by the suction part 26, and one side of the discharge chamber 46 is constituted by the discharge part 27.

  Ink flows into the suction chamber 45 from the outside through the groove portion 21 c formed in the housing 21 and the introduction port 28. Then, when the drive gear 35 and the driven gear 40 are rotated in the r1 direction and the r2 direction in FIG. 5 by the rotation of the drive shaft 22, the ink in the suction chamber 45 (suction side) is brought into contact with the inner peripheral surface of the storage chamber 23. Then, it is confined in a space formed by the tooth gaps of the drive gear 35 and the driven gear 40 and transferred to the discharge chamber 46 side (discharge side). When the tooth tips of the drive gear 35 and the driven gear 40 are separated from the inner peripheral surface of the storage chamber 23, the confined ink is discharged into the discharge chamber 46. As a result, the suction chamber 45 has a relatively low pressure, and the discharge chamber 46 has a higher pressure than the suction chamber 45. The ink in the discharge chamber 46 is pushed out to the concave portion 30 provided on the bottom surface 21 b of the housing 21 through the discharge port 29 by the pressure of the ink sequentially sent out from the gears 35 and 40.

(Lower sealing part B)
Next, the lower sealing portion B that closes the recess 30 and the like of the housing 21 will be described. As shown in FIG. 3, the lower sealing portion B includes a shaft seal member 48 and a lower cover 55. 8 and 9 are perspective views of the shaft seal member 48, FIGS. 10 and 11 are perspective views of the lower cover 55, and FIGS. 12 and 13 are cross-sectional views of the gear pump 20. FIG. 14 is an explanatory diagram for explaining the operation of the shaft seal member 48.

  First, the shaft seal member 48 will be described. As shown in FIG. 8, the shaft seal member 48 is made of an elastomer and includes a base portion 49 formed in a plate shape. On the upper surface 48a of the base portion 49, a covered cylindrical first seal portion 50 as a one-way valve is formed. A thick part 51 is formed below the outer peripheral surface of the first seal part 50. Further, an opening 53 is formed through the lid portion 52 of the first seal portion 50. As shown in FIG. 9, the shaft hole 50a provided in the 1st seal | sticker part 50 is opened by the lower surface 48b. Furthermore, a substantially fan-shaped first seal protrusion 48 c is formed on the upper surface 48 a and the lower surface 48 b of the base portion 49 so as to surround the first seal portion 50.

  Further, as shown in FIGS. 8 and 9, an annular second seal protrusion 48 d is formed on the upper surface 48 a and the lower surface 48 b of the base portion 49 and on the right side of the first seal portion 50. . A communication hole 48e is formed through the right side in the drawing with respect to the second seal protrusion 48d. Further, at the end of the base portion 49 and on the back side in FIG. 8 with respect to the first seal portion 50, a communication groove 48 f is formed so as to extend in parallel with the longitudinal direction of the shaft seal member 48. Furthermore, a third seal protrusion 48g is formed on the upper surface 48a and the lower surface 48b of the base portion 49 so as to surround the communication groove 48f. A fourth seal protrusion 48 h is formed on the upper surface 48 a and the lower surface 48 b of the base portion 49 along the periphery of the base portion 49. Fixing pieces 48 i projecting outward are formed at two locations on the outer surface of the base 49. Each fixed piece 48i includes a hole 48j.

In the shaft seal member 48, two protrusions 21 h (see FIG. 5) formed on the bottom surface 21 b of the housing 21 are inserted into the holes 48 j of the fixed piece 48 i, and the first seal portion 50 is connected to the housing 21. It is fixed to the housing 21 by being fitted into the recess 21f of the first bearing portion 21e. At this time, as shown in FIG. 13, the thick portion 51 of the first seal portion 50 is pressed against the inner peripheral surface of the concave portion 21 f so that the inner peripheral surface of the concave portion 21 f and the outer peripheral surface of the thick portion 51 are hermetically sealed. It is designed to retain sex. The drive shaft 22 is inserted through the opening 53 of the first seal portion 50 so as to be in sliding contact with the inner peripheral surface thereof. The inner peripheral surface of the opening 53 is edged to increase the contact surface pressure with respect to the drive shaft 22 and maintain airtightness. Further, as shown in FIG. 13, a gap is provided between the shaft hole 50 a of the first seal portion 50 and the drive shaft 22, and the shaft hole 50 a is opened on the lower surface 48 b side of the base portion 49. It is in the state.

  As shown in FIG. 12, the base portion 49 is disposed so as to close the second shaft hole 32 of the housing 21 from the bottom surface 21 b side of the housing 21. Further, when the shaft seal member 48 is fixed to the housing 21, the communication groove 48 f formed in the base portion 49 is connected to the groove portion 21 c formed in the bottom surface 21 b of the housing 21. And the communication hole 48e formed in the base | substrate part 49 is arrange | positioned inside the recessed part 30 formed in the housing 21 (refer FIG. 7). As shown in FIG. 12, the recess 30 is sealed by the base 49 of the shaft seal member 48, and a space S1 (see FIGS. 7 and 12) is formed by the recess 30 and the upper surface 48a of the base 49. .

  Next, the lower cover 55 will be described with reference to FIGS. The lower cover 55 includes a plate-like cover base portion 56. On the step surfaces provided on both side surfaces of the cover base portion 56, the latching portions K are formed so as to protrude. Further, as shown in FIG. 10, the cover base 56 is formed on the upper surface 55a of the lower cover 55 so that a substantially fan-shaped first pressure contact portion 55c slightly protrudes from the upper surface 55a at the approximate center. ing. When the lower cover 55 is attached from the lower surface 48b side of the shaft seal member 48, the first pressure contact portion 55c is brought into pressure contact with the first seal protrusion 48c formed on the shaft seal member 48. .

  Further, second and third press contact portions 55d and 55e are formed on the upper surface 55a of the lower cover 55. The second pressure contact portion 55d is formed on the right side in FIG. 10 of the first pressure contact portion 55c so as to slightly protrude from the upper surface 55a, and when the lower cover 55 is attached from the lower surface 48b of the shaft seal member 48, the shaft The seal member 48 is in pressure contact with the second seal protrusion 48d. The third pressure contact portion 55e is formed so as to protrude slightly in an approximately elliptical shape, and is in pressure contact with the third and fourth seal protrusions 48g and 48h of the shaft seal member 48.

  As shown in FIG. 10, the 1st axial hole 57 is formed inside the 1st press-contact part 55c. The first shaft hole 57 passes through the first bearing portion 58 formed in the bottom surface 55 b of the cover base portion 56 and the lower cover 55. Further, an air groove 59 communicating with the first shaft hole 57 is formed on the upper surface 55 a of the lower cover 55. The air groove 59 is linearly recessed in the upper surface 55a, and one end communicates with the first shaft hole 57 and the other end communicates with the air hole 60 opened at the upper surface 55a. As shown in FIG. 12, the air hole 60 is formed in the cover base portion 56 so as to extend in the thickness direction, and communicates with the inside of the resistor housing portion 61 formed on the bottom surface 55 b of the cover base portion 56. ing. As shown in FIG. 11, the resistor accommodating portion 61 is formed in a cylindrical shape and opens on the bottom surface 55 b side of the lower cover 55. A resistor 62 made of a porous metal material (sintered metal) is fitted into the resistor housing 61. The resistor 62 functions as a resistor that limits the amount of air flowing into the air hole 60 side.

  Further, the second seal portion 63 is fitted to the first bearing portion 58. The second seal portion 63 is made of an elastomer and includes a large diameter portion 64 and a small diameter portion 65. The large-diameter portion 64 is formed in a substantially cylindrical shape, and has an inner diameter that allows an interference fit with the first bearing portion 58. The small diameter portion 65 is formed in a bottomed cylindrical shape, and has an inner diameter slightly larger than the outer diameter of the drive shaft 22. An opening 67 is formed through the bottom 66 of the small diameter portion 65. The drive shaft 22 is inserted into the opening 67 so as to be in sliding contact. The inner peripheral surface of the opening 67 is edged.

When the second seal portion 63 is fitted to the lower cover 55, the drive shaft 22 protrudes from the opening 67 of the fitted second seal portion 63, as shown in FIG. Further, the opening 67 increases the contact surface pressure with respect to the drive shaft 22 and maintains airtightness so that air does not flow into the first shaft hole 57 from the gap. In addition, the 2nd seal | sticker part 63 seals, without making air flow in into the housing 21 side like the 1st seal | sticker part 50. FIG.

  Further, as shown in FIG. 10, an introduction groove 69 is formed in the end portion of the upper surface 55 a of the cover base portion 56. An introduction hole 70 communicates with the introduction groove 69. The introduction hole 70 passes through the inside of the cover base portion 56 and the inside of the introduction portion 71 formed on the bottom surface 55b of the lower cover 55, as shown in FIG. An opening is formed on the lower surface of the introduction portion 71.

  Further, as shown in FIG. 10, discharge holes 72 are opened at the corners inside the third press-contact part 55 e of the cover base part 56. The discharge hole 72 passes through the discharge portion 73 formed on the bottom surface 55 b of the cover base portion 56 and the lower cover 55, and opens at the lower surface of the discharge portion 73.

  As shown in FIG. 10, cylindrical insertion insertion portions 74 are formed at four locations on the upper surface 55a of the lower cover 55, and each insertion insertion portion 74 inserts each of the bolts BT so that they can be screwed together. A screw hole R2 is provided. The screw hole R2 passes through the inside of the cover base portion 56 and opens at the bottom surface 55b of the lower cover 55.

  A lower cover 55 is disposed on the lower surface 48 b side of the shaft seal member 48 fixed to the bottom surface 21 b of the housing 21, and each bolt BT screwed into each screw hole R 1 of the housing 21 is screwed into the lower cover 55. When screwed into the hole R2 and fastened with a nut (not shown), the lower cover 55 is fixed to the housing 21 with the shaft seal member 48 interposed therebetween. Then, the introduction hole 70 formed in the introduction portion 71 of the lower cover 55, the introduction groove 69, the communication groove 48f formed in the shaft seal member 48, and the groove portion 21c formed in the housing 21 are communicated with each other. That is, the introduction hole 70 communicates with the introduction port 28 that communicates with the accommodation chamber 23 of the housing 21 through the introduction groove 69, the communication groove 48 f, and the groove portion 21 c.

  Further, it is constituted by a discharge hole 72 formed in the discharge portion 73 of the lower cover 55, a communication hole 48 e formed in the shaft seal member 48, a recess 30 formed in the housing 21, and a base portion 49 of the shaft seal member 48. Are connected to each other. That is, the discharge hole 72 communicates with the discharge port 29 communicating with the storage chamber 23 of the housing 21 through the communication hole 48e and the space S1.

  Therefore, the ink introduced from the introduction hole 70 of the lower cover 55 is introduced into the suction chamber 45 through the introduction groove 69, the communication groove 48 f, the groove portion 21 c, and the introduction port 28. The ink transferred from the suction chamber 45 to the discharge chamber 46 due to the rotation of the drive gear 35 and the driven gear 40 is a space S <b> 1 constituted by the recess 30 and the base portion 49 of the shaft seal member 48 from the discharge port 29. (See FIG. 7). As shown in each arrow direction in FIG. 7, the ink ejected into the space S <b> 1 is the outer circumference of the first bearing portion 21 e, the gap between the first bearing portion 21 e and the second bearing portion 21 g, and the second bearing. It flows toward the communication hole 48e of the shaft seal member 48 through the space between the portion 21g and the inner peripheral surface of the recess 30 or the like. The ink flowing out from the communication hole 48e is discharged to the outside through the discharge hole 72 of the lower cover 55 connected to the communication hole 48e.

Further, when the lower cover 55 is fixed to the housing 21 with the shaft seal member 48 interposed therebetween, as shown in FIG. 12, the resistor accommodating portion 61 formed on the lower cover 55 Similarly, the shaft hole 50 a of the first seal portion 50 of the shaft seal member 48 communicates with the air hole 60 and the air groove 59 formed in the lower cover 55. That is, the air that has passed through the resistor 62 can flow into the first seal portion 50 through the air hole 60 and the air groove 59. At this time, the amount of air flowing into the first seal portion 50 is limited by the resistor 62. The lid portion 52 (see FIG. 13) of the first seal portion 50 is connected to the first seal portion 5.
It bends due to the pressure difference between the internal pressure of 0 and the external pressure. The resistor housing 61, the air hole 60, the air groove 59, the shaft hole 50a, the recess 21f, and the first shaft hole 31 constitute a communication port that communicates from the outside of the housing 21 to the housing chamber 23 side.

  More specifically, as shown in FIG. 13, the recess 21 f in which the first seal portion 50 is accommodated communicates with the first accommodation chamber 24 side via the gap between the first shaft hole 31 and the drive shaft 22. is doing. For this reason, the pressure on the first storage chamber 24 side is applied as an external pressure to the lid portion 52 of the first seal portion 50. Then, the pressure on the first storage chamber 24 side is lower than the internal pressure of the first seal portion 50, but when the pressure is not less than a predetermined value, as shown in FIG. 52 is not bent. Further, when the external pressure of the first seal portion 50 is lower than the internal pressure and less than a predetermined value (negative pressure state), as shown in FIG. It will bend in the storage chamber 24 side (outside), and will be in the state by which the opening part 53 was expanded. As a result, the space between the inner peripheral surface of the opening 53 and the outer peripheral surface of the drive shaft 22 is in an airtight state, and the air in the shaft hole 50 a of the first seal portion 50 flows from the opening 53 to the housing 21. It flows out into the recess 21f (see FIG. 13). The air that has flowed into the recess 21 f flows into the first storage chamber 24 through the gap between the first shaft hole 31 and the drive shaft 22 of the housing 21. The air that has flowed into the first storage chamber 24 flows into a relatively low-pressure location such as a space between the tooth spaces of the gears 35 and 40 and the inner surface of the storage chamber 23 in the form of bubbles and expands. Then, the rotation of the gears 35 and 40 causes the tooth tips to reach the discharge chamber 46 side and away from the inner side surface of the storage chamber 23, so that the bubbles are reduced and the discharge chamber has a relatively high pressure. 46 is discharged. As a result, rapid ink flow on the discharge chamber 46 side is prevented.

  On the other hand, when the pressure (external pressure) on the first storage chamber 24 side becomes larger than the internal pressure of the first seal portion 50 for some reason, the lid portion 52 is moved as shown in FIG. Since it is wound inside and bends, the opening 53 is reduced in diameter, and the airtightness between the inner peripheral surface of the opening 53 and the outer peripheral surface of the drive shaft 22 is maintained. That is, the first seal portion 50 functions as a one-way valve that allows air to flow from the outside of the housing 21 into the storage chamber 23 only when the storage chamber 23 is in a negative pressure state.

  Further, as shown in FIG. 12, the shaft seal member 48 sandwiched between the lower cover 55 and the housing 21 has a fourth seal protrusion 48h, the third pressure contact portion 55e of the lower cover 55, and the housing 21. The space S1 formed by the recess 30 of the housing 21 and the shaft seal member 48 is kept in pressure contact with the bottom surface 21b of the housing 21b. Further, the third seal protrusion 48g of the shaft seal member 48 is pressed between the third pressure contact portion 55e and the bottom surface 21b around the groove portion 21c of the housing 21, so that the groove portion 21c and the communication groove 48f of the shaft seal member 48 are provided. The introduction groove 69 of the lower cover 55 is sealed in an airtight state to maintain the airtightness of the ink flow path. Further, the first and second seal protrusions 48 c and 48 d of the shaft seal member 48 are between the first and second press contact portions 55 c and 55 d and the first and second bearing portions 21 e and 21 g of the housing 21. The first and second shaft holes 31 and 32 are sealed in pressure-tight manner in an airtight state.

(Upper sealing part A)
Next, the upper sealing portion A will be described with reference to FIGS. FIG. 15 is an exploded perspective view of the upper sealing portion A. FIG. As shown in FIG. 15, the upper sealing portion A includes a sealing plate 75 as a first sealing portion, a packing 77 as a second sealing portion, a push plate 78, and a regulating member as a biasing means. 80. 16 is a perspective view of the packing 77, and FIG. 17 is a perspective view of the regulating member 80.

As shown in FIG. 15, the sealing plate 75 is made of a metal plate and is formed in a substantially elliptical shape. As shown in FIGS. 12 and 13, the sealing plate 75 is provided on the upper surface 21 a of the housing 21 so as to be located inside the protrusion 21 d. And the sealing board 75 is the accommodation chamber 2.
The three-side surface is positioned in the axial direction of each gear by abutting against the annular protrusions 36 and 41 of the drive gear 35 and the driven gear 40 accommodated in the accommodation chamber 23. As a result, a slight gap is generated between the sealing plate 75 and the upper surface 21 a of the housing 21.

  A packing 77 is attached from the outside of the sealing plate 75. As shown in FIG. 15, the packing 77 is made of a flexible material such as an elastomer and is formed in a substantially rectangular plate shape having a size capable of covering the opening of the storage chamber 23. As shown in FIG. 16, the packing 77 has a recess 77c formed on the lower surface 77b thereof. Further, support portions 77 d are recessed on both sides of the packing 77. Further, four through holes H3 through which the respective bolts BT are inserted are formed through each corner of the packing 77. As shown in FIG. 12, the packing 77 is disposed from above the sealing plate 75, and when a pressing force or the like is applied from the outside, the lower surface 77b of the packing 77 is pressed against the protrusion 21d of the housing 21, The pressed portion is elastically deformed and is in close contact with the protrusion 21d. As a result, the opening of the storage chamber 23 is sealed in an airtight state. At this time, the sealing plate 75 is accommodated in the recess 77 c of the packing 77. At this time, the bottom surface of the recess 77c of the packing 77 and the sealing plate 75 are not in pressure contact with each other.

  A pressing plate 78 is attached from the upper surface 77 a side of the packing 77. As shown in FIG. 15, the push plate 78 is formed in a square frame shape, and has an opening 78c on the inner side. In each corner of the push plate 78, four through holes H4 are formed through the bolts BT. In addition, a regulating member 80 is attached to the upper surface 78 a of the push plate 78.

  As shown in FIG. 15, the regulating member 80 has a main body portion 81 formed in a substantially frame shape and two arm portions 82 extending downward from both sides of the main body portion 81. Each arm part 82 is formed in a substantially L shape, and its tip is bent inward. A hole is formed at the tip of the arm portion 82. Furthermore, penetration holes H5 for penetrating the bolts BT are formed at the respective corners of the main body 81.

  As shown in FIGS. 2 and 17, two restricting portions 84 are formed on both sides of the opening 83 provided inside the main body 81. As shown in FIGS. 2 and 17, each restricting portion 84 is formed in a crank shape by bending an elongated plate-like piece at two locations.

  As shown in the left restricting portion 84 in FIG. 17, the restricting portion 84 includes an inwardly extending first horizontal portion H1, a vertical portion P1 extending vertically downward from the first horizontal portion, and an inner side from the vertical portion. And a second horizontal portion H2 bent toward the front. The lower surface of the second horizontal portion H2 is provided with a pressing portion 85 that is protruded by pressing. Further, the vertical portion P <b> 1 of the restricting portion 84 has substantially the same length as the thickness of the pressing plate 78.

  As shown in FIG. 2, when the regulating member 80 is attached from above the push plate 78, the latching portion K of the lower cover 55 is engaged with the hole at the tip of the arm portion 82 of the regulating member 80. . Further, the packing 77 is disposed so as to fit inside the support plate SP of the housing 21. At this time, the arm portion 82 is fitted to the support portion 77 d of the packing 77. Then, each bolt is inserted into each of the insertion holes H3 to H5, and a nut (not shown) is fastened to the tip of the bolt BT protruding from the screwing hole R2 of the lower cover 55.

As a result, the pressing plate 78, the packing 77, the sealing plate 75, and the housing 21 are fixed to the lower cover 55 by the restriction member 80. Then, as shown in FIGS. 2 and 12, the pressing portion 85 of the regulating member 80 comes into contact with the upper surface 77a of the packing 77, and the contact surface is pressed downward. Further, the pressing portion 85 of the restricting portion 84 is disposed so as to be positioned on an axis line obtained by extending the axis of the drive gear 35 and the driven gear 40. That is, since the restricting portion 84 presses the axial center position of each gear 35, 40, the sealing plate 75 contacts only the annular protrusions 36, 41 of each gear 35, 40 as shown in FIG. The upper surfaces 35 a and 40 a other than the annular protrusions 36 and 41 are not in contact with the sealing plate 75. Further, as shown in FIG. 13, the packing 77 is pressed against the protrusion 21d by the fastening force of the bolt BT, etc., and the opening of the storage chamber 23 is kept airtight while being restricted from moving toward the sealing plate 75. Seal. For this reason, even if the sealing plate 75 is not in close contact with the upper surface 21 a of the housing 21, the packing 77 seals the opening of the accommodation chamber 23 from the outside.

  Further, since the packing 77 is pressed against the housing 21 outside the sealing plate 75, the pressing force applied to the packing 77 is not applied to the sealing plate 75. For this reason, in this embodiment, the packing 77 is pressed against the housing 21 with a relatively large pressing force.

  Next, the operation of the gear pump 20 will be described. At the time of cleaning, the lifting mechanism is driven to seal the nozzle opening surface of the recording head 8 with the cap 12. When a drive command is output from the control unit (not shown) of the printer 1 at a predetermined timing, the drive motor is driven and the drive shaft 22 rotates in the forward direction. As a result, as shown in FIG. 6, the drive gear 35 rotates in the r1 direction, and the driven gear 40 rotates in the r2 direction by meshing with the drive gear 35.

  At this time, the annular protrusions 36 and 41 formed on the upper surfaces 35 a and 40 a of the gears 35 and 40 are urged toward the bottom surface side of the storage chamber 23 by the restriction portion 84 of the restriction member 80. In addition, the annular protrusions 37 and 42 formed on the lower surfaces 35 b and 40 b of the gears 35 and 40 are also urged toward the housing 21 by the restricting portion 84. Therefore, each gear 35, 40 has its annular projections 36, 37, 41, 42 in contact with the sealing plate 75 and the housing 21, respectively, and the other upper surfaces 35a, 40a and lower surfaces 35b, 40b are the sealing plate 75. And the housing 21 rotates while maintaining a non-contact state in which the housing 21 does not slide. As a result, the diameter and contact area of the contact portion between the sealing plate 75 or the housing 21 and the gears 35 and 40 are reduced, so that the load on the gears 35 and 40 is reduced.

  When the drive gear 35 and the driven gear 40 rotate, the ink in the suction chamber 45 is confined in the space formed by the tooth grooves of the drive gear 35 and the driven gear 40 and the inner peripheral surface of the storage chamber 23, and enters the discharge chamber 46. Sent sequentially. For this reason, the suction chamber 45 is temporarily in a low pressure state. Then, the ink in the cap 12 flows into the suction chamber 45 through the tube 13 in an attempt to eliminate the low pressure state of the suction chamber 45. At this time, the pressure in the suction chamber 45 is lower than the pressure in the discharge chamber 46, but each gear is in contact with the annular projections 36, 37, 41, 42 and the sealing plate 75 and the housing 21. The clearance between the upper surfaces 35a and 40a of the 35 and 40 and the sealing plate 75 and the clearance between the lower surfaces 35b and 40b and the housing 21 are 50 μm or less. For this reason, the amount of ink flowing into the suction chamber 45 from the ejection chamber 46 through the gap is very small, and the suction capability is not reduced by the backflow of ink.

  Furthermore, when the pressure in the first storage chamber 24 becomes lower than a predetermined value due to high-speed rotation of the drive gear 35 and the driven gear 40, the pressure difference between the internal pressure of the first seal portion 50 and the external pressure is caused. As shown in FIG. 14B, the lid portion 52 of the first seal portion 50 bends toward the first storage chamber 24 side. As a result, the opening 53 expands, and the air that has passed through the resistor 62 flows into the first storage chamber 24 through the air hole 60, the air groove 59, and the first shaft hole 31. As described above, even if a negative pressure is generated in the storage chamber 23, if the pressure is equal to or higher than a predetermined value, the lid portion 52 is moved to the storage chamber 23 side as shown in FIG. Does not flex.

The air that has flowed into the housing chamber 23 is taken into the air gaps of the suction chamber 45, the drive gear 35, and the driven gear 40, which are at a relatively low pressure, in a bubble state. Then, it expands in a space constituted by the tooth grooves and the inner peripheral surface of the storage chamber 23, and is generated in the vicinity of the discharge chamber 46 by contraction of the bubbles when discharged to the discharge chamber 46 side. Reduces easy ink flow. By preventing this rapid ink flow, noise generated by the flow is prevented.

  The ink that flows into the suction chamber 45 from the cap 12 and is sent out to the discharge chamber 46 side by the drive gear 35 and the driven gear 40 passes through the discharge port 29, the space S 1, the communication hole 48 e, and the discharge hole 72. 73 to the tube 15 connected to 73. The ink that has flowed into the tube 15 is discharged to the waste ink tank 16. As a result, the ink and air in the cap 12 are sucked, the inside of the cap 12 is in a negative pressure state, and fluid such as ink and bubbles is discharged from the nozzles of the recording head 8.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the housing chamber 23 is sealed in the gear pump 20, the sealing plate 75 that prevents the backflow of fluid from the discharge side to the suction side, and the packing 77 that seals the housing chamber 23 in an airtight state. And was prepared. The sealing plate 75 is in contact with the annular protrusions 36 and 41 of the drive gear 35 and the driven gear 40. For this reason, the gap between the sealing plate 75 and the upper surfaces 35a, 40a of the gears 35, 40 is reduced, so that the backflow of fluid from the discharge side of the storage chamber 23 to the suction side is prevented, and the suction or discharge operation of the pump The performance in can be stabilized. Further, the packing 77 is made of a flexible material such as an elastomer, and is pressed against the upper surface 21a of the housing 21 against the protrusion 21d formed so as to protrude outward from the regulating surface 76. For this reason, even if a clearance gap arises between the sealing board 75 and the housing 21, the storage chamber 23 can be sealed in an airtight state.

  Further, since the sealing plate 75 is pressed against the gears 35 and 40 only by the pressing force generated by the restricting portion 84 of the restricting member 80, the pressing force on the gears 35 and 40 can be stabilized. Further, the gears 35 and 40 are not excessively pressed. For this reason, the load with respect to each gear 35 and 40 can be reduced. Therefore, the sealing plate 75 can prevent the backflow in the storage chamber 23 while contacting the gears 35 and 40 with an appropriate pressing force.

  Further, since the packing 77 is sealed by pressing it against the protrusions 21d provided outside the sealing plate 75, the pressing force on the packing 77 generated by fastening the bolt BT or the like is applied to the sealing plate 75. Will not join. For this reason, even if the packing 77 is pressed against the protrusion 21d with a large pressing force in consideration of the deterioration of the packing 77 due to long-term use, the load on the gears 35 and 40 is not increased. For this reason, since the packing 77 can be pressed against the housing 21 with a relatively large force, the sealing performance of the housing chamber 23 can be continuously secured even when the gear pump 20 is used for a long period of time.

  (2) According to the present embodiment, the annular protrusions 36, 37, 41, 42 that abut the sealing plate 75 and the housing 21 on the upper surfaces 35 a, 40 a and the lower surfaces 35 b, 40 b of the drive gear 35 and the driven gear 40, respectively. Was provided. The surfaces other than the annular protrusions 36 and 41 of the upper surfaces 35a and 40a of the gears 35 and 40 are in a non-contact state with the sealing plate 75. Further, the surfaces other than the annular protrusions 37 and 42 of the lower surfaces 35b and 40b of the gears 35 and 40 are in a non-contact state with the housing 21. Therefore, since the driving gear 35 and the driven gear 40 have a small diameter at the contact portion, the friction load can be reduced. In addition, since the sliding areas of the sealing plate 75 and the housing 21 are reduced, it is possible to reduce the viscous load when the gears 35 and 40 are rotated while preventing the backflow in the storage chamber 23. it can.

  (3) According to the above-described embodiment, the packing 77 is plate-shaped and has a size that can cover the opening of the storage chamber 23. Therefore, since the packing 77 can be made into a simple structure, a manufacturing process or an assembly process can be reduced. Further, since the packing 77 is formed in a plate shape, a molding error hardly occurs and the reliability of the sealing action can be improved.

  (4) In the above embodiment, the restriction member 84 is provided on the restriction member 80. Then, the restricting portion 84 presses the shaft center positions of the drive gear 35 and the driven gear 40 to the housing 21 side via the sealing plate 75 so as to reduce the gap between the sealing plate 75, each gear 35 and the housing 21. I made it. That is, the restricting portion 84 presses the axial center position of each of the gears 35 and 40, thereby preventing ink backflow in the storage chamber 23. Moreover, since the restricting portion 84 presses the axial center position of each gear 35, 40, the surfaces other than the annular projections 36, 41 of each gear 35, 40 come into contact with the sealing plate 75, and each gear 35, 40 It is possible to prevent the 40 friction load from increasing.

  (5) In the above embodiment, the housing 21 is formed with a protrusion 21 d that presses against the packing 77. For this reason, since the area where the packing 77 is pressed is reduced, the packing 77 can be brought into close contact with the protrusion 21d even with a relatively small pressing force. For this reason, the opening of the storage chamber 23 can be sealed in an airtight state.

  (6) In the above embodiment, the lower cover 55 is provided with the resistor housing portion 61, the air hole 60, and the air groove 59, thereby forming an air flow path that communicates from the outside to the housing chamber 23. Then, a first seal portion 50 that communicates with the air flow path and flows air into the accommodation chamber 23 was fitted into the recess 21 f of the housing 21. The first seal portion 50 is formed so that the portion excluding the thick portion 51 can be bent, and an opening 53 is formed in the lid portion 52 so as to be slidable through the drive shaft 22. I tried to support it. And when the 1st storage chamber 24 side becomes a pressure (negative pressure state) less than a predetermined value, the opening part 53 expands toward the storage chamber 23 side, and drives the opening part 53 inner peripheral surface. The space between the outer peripheral surface of the shaft 22 was made to be in a non-airtight state. For this reason, the air that has flowed into the first seal portion 50 via the air flow path flows into the accommodating chamber 23 through the space between the expanded opening 53 and the drive shaft 22. As a result, when air is mixed into the ink stored in the space formed by the tooth spaces of the gears 35 and 40 and the inner peripheral surface of the storage chamber 23 and the ink is discharged to the discharge chamber 46 side, The pressure difference with the discharge chamber 46 can be reduced. For this reason, it is possible to eliminate the rapid flow of ink caused by the pressure difference generated in the vicinity of the discharge chamber 46, and to prevent vibration and noise due to the rapid flow of ink.

In addition, you may change this embodiment as follows.
-In the said embodiment, you may make it use the gear pump 20 not only as a suction pump but as a pressurization pump. For example, the fluid (air, ink) discharged from the gear pump 20 may be sent out to an ink cartridge containing the absorbent material, and the waste ink absorbed by the absorbent material may be absorbed. In this case, of the fluid sent out from the gear pump 20, only the waste ink is absorbed by the absorbent material, and the air is filled in the case of the ink cartridge. That is, in this case, the gear pump 20 functions as a pressurizing pump that sends fluid to the ink cartridge. As a result, when an ink pack made of a flexible member is accommodated in the ink cartridge, the air filled in the case crushes the ink pack, and the ink is pushed out from the ink pack. Derived to the 8th side. In such a case, the drive gear 35 and the driven gear 40 of the gear pump 20 rotate at a high speed and the inside of the discharge chamber 46 becomes high pressure, but the gear pump 20 presses the drive gear 35 and the driven gear 40 by the regulating member 80. As a result, the gears 35 and 40 do not rampage.

  In the above embodiment, a step surface 90 may be formed on the upper surface 21a of the housing 21 as shown in FIG. The packing 77 may be pressed against the stepped surface 90 so that the packing 77 and the housing 21 are in close contact with each other. Alternatively, the packing 77 may be provided with a protrusion, and an engagement recess that engages with the protrusion may be formed on the upper surface 21 a of the housing 21 so that the packing 77 and the housing 21 are brought into close contact with each other.

In the above-described embodiment, an air flow path constituted by an air groove or the like is provided, and the first seal portion 50 as a one-way valve is provided in the air flow path so that air flows into the storage chamber 23. However, this configuration may be omitted when vibration and noise due to the pressure difference in the storage chamber 23 are not a problem. In this case, the gear pump 20 has a simpler configuration.

  In the above embodiment, the urging means may be composed of a compression spring or the like. In this case, the device tends to be large, but the axial positions of the gears 35 and 40 can be more reliably pressed.

  In the above embodiment, any one of the annular protrusions 36, 37, 41, 42 of the gears 35, 40 may be omitted. Further, when the gears 35 and 40 are not easily violated during rotation and the load during rotation of the gears 35 and 40 is not particularly problematic, all of the annular protrusions 36, 37, 41, and 42 may be omitted. .

  In the above embodiment, a gap (backlash) may be provided between the recess 77 c of the packing 77 and the sealing plate 75 in a state where the upper sealing portion A is attached to the housing 21. If it does in this way, it can be in the state where the force added to packing 77 does not apply to sealing board 75 more certainly.

  In the above embodiment, the gear pump 20 may be mounted on another device instead of the printer 1. Also in other devices, it is possible to exhibit the effect of preventing suction failure or discharge failure and reducing the load on each gear (motor).

  In the above embodiment, the printer 1 that ejects ink has been described as the liquid ejecting apparatus, but other liquid ejecting apparatuses may be used. For example, printing apparatuses including fax machines, copiers, etc., liquid ejecting apparatuses that eject liquids such as electrode materials and coloring materials used in the production of liquid crystal displays, EL displays, and surface-emitting displays, and bio-organic materials used in biochip manufacturing It may be a liquid ejecting apparatus for ejecting a liquid or a sample ejecting apparatus as a precision pipette. The fluid (liquid) is not limited to ink, and may be applied to other fluids (liquids).

FIG. 2 is a plan view of the printer according to the embodiment. The perspective view of the gear pump mounted in the printer. The exploded perspective view of the gear pump. The perspective view explaining the housing and each gear of the gear pump. The perspective view explaining the housing and each gear of the gear pump. The top view of the housing of the state which accommodated each gearwheel. The bottom view of the housing. The perspective view of the shaft seal member which comprises the lower side sealing part of the gear pump. The perspective view of a coaxial seal member. The perspective view of the lower cover which comprises the same lower side sealing part. The perspective view of the lower cover. Sectional drawing of the gear pump. The cross-sectional enlarged view of the gear pump. It is explanatory drawing explaining the effect | action of a coaxial seal member, Comprising: (a) is a sealing state, (b) is an expanded state, (c) shows the diameter-reduced state when external pressure is large. The disassembled perspective view of the upper side sealing part of the gear pump. The perspective view of the packing which comprises the same upper side sealing part. The perspective view of the control member which comprises the same upper side sealing part. The principal part sectional view explaining another example of the gear pump of this embodiment. Explanatory drawing of the conventional gear pump.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer as a liquid ejecting apparatus, 20 ... Gear pump, 21 ... Housing, 21d ... Projection as 2nd positioning part, 21f ... Recessed part which comprises a communicating port, 23 ... Storage chamber, 31 ... Constructing a communicating port 1st shaft hole, 35 ... drive gear, 36, 37, 41, 42 ... annular projection as projection, 40 ... driven gear, 50 ... first seal part as one-way valve, 50a ... communication port A shaft hole constituting 59, an air groove constituting the communication port, 60 an air hole constituting the communication port, 61 a resistor accommodating portion constituting the communication port, 75 a sealing plate as a first sealing portion , 76 ... restriction surface as the first positioning part, 77 ... packing as the second sealing part, 80 ... restriction member as the urging means, 84 ... restriction part as the urging means, 90 ... restriction surface.

Claims (7)

In a gear pump that includes a drive gear and a driven gear in a housing chamber provided in a housing, and leads the fluid from the suction side to the discharge side by the rotation of the drive gear and the driven gear.
The abutment gear contacts at least a part of the drive gear and the driven gear accommodated in the accommodation chamber, and the opening of the accommodation chamber is sealed to prevent the backflow of fluid from the discharge side to the suction side of the accommodation chamber. A first sealing portion;
A second sealing portion that seals the accommodation chamber in an airtight state outside the first sealing portion ;
The gear pump through a first sealing portion, characterized by comprising a biasing means for biasing the axial position of the drive gear and the driven gear. The gear pump according to claim 1, wherein
The gear pump, wherein the second sealing portion is made of a flexible material. The gear pump according to claim 1 or 2,
At least one of a projecting portion that contacts the first sealing portion and a projecting portion that contacts the housing is formed on each side surface of the drive gear and the driven gear. The gear pump according to any one of claims 1 to 3,
The gear pump according to claim 1, wherein the second sealing portion is plate-shaped and has a size capable of covering the opening of the storage chamber. In the gear pump as described in any one of Claims 1-4 ,
The gear pump according to claim 1, wherein a pressure contact portion that is in pressure contact with the second sealing portion is formed in the housing. In the gear pump as described in any one of Claims 1-5 ,
A communication port that communicates from the outside of the housing to the storage chamber is provided, and the communication port has a one-way valve that allows air to flow into the storage chamber from the outside of the housing only when the storage chamber is in a negative pressure state. A gear pump characterized by being provided. A liquid ejecting apparatus having a gear pump according to any one of claims 1-6.

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