JP2005163711A - Gear pump and liquid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear pump capable of improving the performance of a pump without increasing accuracy and a liquid ejecting apparatus using the gear pump.
A gear pump includes a driving gear and a driven gear in a housing chamber provided in a housing. The drive gear 26 is positioned by contact with the side surface of the storage chamber 23, and the drive shaft 22 is inserted into the shaft hole 35 with a gap. The driven gear 27 is positioned by contact with the side surface of the storage chamber 23, and the driven shaft 30 fitted into the driven gear 27 has a gap between the housing 21 and shaft support portions 29 and 44 formed in the cover. It is provided and inserted.
[Selection] Figure 5

Description

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

Conventionally, the gear pump is superior in that the structure is simpler than other pumps. An example of this 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 formed in the housing 101 (see, for example, Patent Document 1). The driving gear 103 and the driven gear 104 are rotatably supported by rotating shafts 105 and 106, respectively. A rotation shaft 105 connected to the drive gear 103 is inserted into a shaft hole (not shown) formed in the housing 101 and is inserted into the shaft hole 107 of the drive gear 103, and a part of the rotation shaft 105 is external to the housing 101. Protruding. The driven gear 104 is rotatably supported by a rotating shaft 106 that passes through a shaft hole 108 provided in the center of the driven gear 104 and a shaft hole (not shown) of the housing 101. When the drive gear 103 and the driven gear 104 rotate, the liquid in the suction chamber 110 provided in the storage chamber 102 is in a space formed by the tooth grooves of the drive gear 103 and the driven gear 104 and the side surface 111 of the storage chamber 102. It is confined and sent sequentially to the discharge chamber 112 side.
JP-A-8-093657

  However, in this gear pump 100, if a relatively large discharge amount, discharge pressure or the like is to be ensured, the drive gear 103, the driven gear 104, and the housing 101 need to be processed with high accuracy. That is, when the accuracy of the gears 103 and 104 and the housing 101 is reduced and the gap between the gears 103 and 104 and the side surface 111 of the storage chamber 102 is increased, the liquid leaks from the gap and the liquid is efficiently discharged. It cannot be sent out. On the other hand, in order to make the gaps between the gears 103 and 104 and the housing 101 as small as possible, it is necessary to process the diameters of the gears 103 and 104, the inner diameter of the housing chamber 102 of the housing 101, and the like with high accuracy. The manufacturing cost and the number of manufacturing processes increase.

  An object of the present invention is to provide a gear pump capable of improving the performance of the pump without increasing accuracy and a liquid ejecting apparatus using the gear pump.

  The gear pump of the present invention accommodates a drive gear and a driven gear in a housing chamber provided in a housing, and drives and connects a drive shaft fitted and supported in a shaft hole formed in the housing to the shaft hole of the drive gear. In the gear pump in which the teeth of the drive gear and the driven gear are rotated so that the teeth of the drive gear and the driven gear are in sliding contact with the inside of the storage chamber according to the rotation of the drive shaft, the shaft hole of the drive gear provides a gap in the drive shaft. Are formed in a shape to be connected and driven.

  According to this, the drive gear is positioned by slidingly contacting the inside of the storage chamber. For this reason, the sealing property of the space comprised by the tooth space of a drive gear and the inner side of a storage chamber becomes high, and the performance of a pump can be improved. Further, the shaft hole of the drive gear is formed in a shape that allows the drive shaft to be inserted with a gap. For this reason, even when a deviation occurs between the position of the shaft hole of the drive gear and the position of the drive shaft, the drive shaft can absorb the deviation in the shaft hole provided with the gap, so the drive shaft is fitted into the shaft hole. Can be inserted. Therefore, the pump performance can be ensured without processing the housing and the drive gear with high accuracy.

  The gear pump of the present invention houses a drive gear and a driven gear in a housing chamber provided in a housing, seals the housing chamber with a sealing plate, and sets the driven shaft of the driven gear to the housing and the sealing plate. In the gear pump that is inserted into the shaft support portion formed in the shaft and is rotated so that the teeth of the drive gear and the driven gear are in sliding contact with the inside of the storage chamber, the shaft support portion is configured such that the driven shaft has a gap. It is formed in a shape to be provided and inserted.

  According to this, the driven gear is positioned by slidingly contacting the inside of the storage chamber. For this reason, the sealing property of the space comprised by the tooth space of a driven gear and the inner side of a storage chamber becomes high, and the performance of a pump can be improved. Moreover, the shaft support part formed in the housing and the sealing plate is formed in a shape in which the driven shaft inserted into the driven gear is inserted with a gap. For this reason, even when a displacement occurs between the position of the driven shaft and the position of the shaft support portion, the driven shaft can absorb the displacement within the shaft support portion provided with the gap, so that the driven shaft is used as the shaft support portion. Can be inserted. Therefore, the performance of the pump can be ensured without machining the driven shaft and the housing of the driven gear with high accuracy.

In this gear pump, biasing means for biasing the driven shaft to a reference position is provided in a gap between the shaft support portion and the driven shaft.
According to this, since the biasing means for biasing the driven gear to the reference position is provided in the shaft support portion, it is possible to prevent the driven gear from being displaced due to the pressure difference generated in the storage chamber. . For this reason, it is possible to prevent vibration and noise due to the displacement of the driven gear.

In this gear pump, the urging means urges the driven shaft of the driven gear in a direction opposite to the liquid discharge side.
According to this, the urging means urges the shaft portion of the driven gear in the direction opposite to the discharge side. For this reason, in the vicinity of the discharge side space, with the rotation of the gear, a space constituted by the tooth groove of the driven gear and the inside of the storage chamber opens, and when the pressure of the liquid in the tooth groove changes suddenly, It is possible to prevent the driven gear from moving due to the momentum.

The liquid ejecting apparatus of the present invention includes the gear pump described above.
According to this, since the gear pump is mounted on the liquid ejecting apparatus, the gear pump can be used for head cleaning and the like.

  Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS. FIG. 1 is a plan view for explaining an outline of an ink jet recording apparatus (hereinafter referred to as a printer) as a liquid ejecting apparatus of 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 P1 and P2. 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 5 (the surface facing the platen 3). Although not shown, the recording head 8 has a nozzle forming surface on the lower surface facing the platen 3.

  The frame 2 includes a cartridge case 9. In the cartridge case 9, an ink cartridge 10 as a liquid storage unit is loaded. In this embodiment, six ink cartridges 10 are provided, and each ink cartridge 10 stores various inks. The ink stored in these ink cartridges 10 is supplied to the recording head 8 via each tube T by being pressurized by a pressure pump (not shown).

  The ink that has flowed into the recording head 8 is pressurized by a piezoelectric element (not shown) provided in the recording head 8 and is ejected 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 holder 11 is provided in a non-printing area in the frame 2. The cap holder 11 is provided with a box-shaped cap member 12 made of a flexible member, and is arranged so that the opening side thereof faces the nozzle forming surface of the recording head 8. The cap holder 11 is driven by a driving mechanism (not shown) when the printer 1 is in a non-printing state or the like, and causes the cap member 12 to be in close contact with the nozzle forming surface in order to prevent drying near the nozzle opening.

  The cap holder 11 is formed with a suction port (not shown) that allows the inside of the cap member 12 to communicate with the outside, and one end of a tube 13 is connected to the suction port. The other end of the tube 13 is connected to a pump unit 14 provided in the frame 2. Further, a waste ink tank 16 is connected to the pump unit 14 via a tube 15. Therefore, when the cap member 12 seals the nozzle formation surface, when the pump unit 14 is driven, air, ink, and the like in the space formed by the cap member 12 and the nozzle formation surface are sucked. A negative pressure is generated in the space. As a result, so-called cleaning is performed in which ink and bubbles having increased viscosity in the nozzles of the recording head 8 and ink and dust adhering to the nozzle forming surface are sucked out. Ink or the like sucked from the recording head 8 is sent to the waste ink tank 16 via the pump unit 14.

  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 provided in the pump unit 14 will be described with reference to FIGS. FIG. 2 is a perspective view showing the entire gear pump 20, and FIGS. 3 and 4 are exploded perspective views of the gear pump 20. 5 and 6 are plan views for explaining the inside of the gear pump 20. FIG. 5 shows a state where each gear is accommodated, and FIG. 6 shows a state where each gear is not accommodated.

  As shown in FIG. 2, the gear pump 20 includes a housing 21, and a drive shaft 22 protrudes rotatably from a bearing portion 21 b formed on the outer surface of the housing 21. The drive shaft 22 is connected to the drive mechanism, and is rotated in the r1 direction by driving of the drive motor to rotate a drive gear 26 (see FIG. 3) in the housing 21.

As shown in FIG. 3, the housing 21 is formed in a substantially rectangular parallelepiped shape, and the accommodation chamber 23 is recessed in one side surface 21a. The storage chamber 23 includes a first storage portion 24 and a second storage portion 25. The first and second storage portions 24 and 25 are each formed in a substantially columnar shape, and overlap each other to form a storage chamber 23. In addition, a suction part 23 a and a discharge part 23 b are recessed in the side surface of the storage chamber 23 (inside the housing 21) so as to be sandwiched between the first storage part 24 and the second storage part 25.

  As shown in FIG. 6, a shaft hole 28 is formed through the bottom surface of the first housing portion 24. The shaft hole 28 rotatably supports the drive shaft 22. A shaft support portion 29 is recessed on the bottom surface of the second housing portion 25. The shaft support portion 29 supports one end of a driven shaft 30 of a driven gear 27 described later. Further, the shaft support portion 29 is formed such that its inner diameter is larger than the outer diameter of the driven shaft 30 of the driven gear 27. Further, a groove 31 is continuously formed in the shaft support portion 29.

  Furthermore, screw fitting insertion portions 21d are formed at the four corners of the side surface 21a of the housing 21, respectively. These screw fitting insertion portions 21d are formed in a cylindrical shape, and are arranged so that screws P described later can be fitted therein.

  Next, the drive gear 26 and the driven gear 27 will be described. As shown in FIGS. 3 to 5, the drive gear 26 is formed with a shaft hole 35 penetrating substantially at the center thereof. In the shaft hole 35, the tip end portion 22a of the drive shaft 22 is fitted. As shown in FIGS. 3 and 5, the drive shaft 22 has a front end portion 22 a having a substantially rectangular cross section. And parts other than the front-end | tip part 22a of the drive shaft 22 are formed in the column shape. In accordance with the shape of the tip 22a, the shaft hole 35 is formed to have a substantially rectangular parallelepiped shape. Furthermore, as shown in FIG. 5, the shaft hole 35 is formed so that its inner diameter is larger than the outer diameter of the tip end portion 22 a of the drive shaft 22. That is, there is some play between the tip 22 a of the drive shaft 22 and the shaft hole 35. Accordingly, the shaft hole 35 engages with the corner of the tip 22a and the shaft hole 35 when the tip 22a of the drive shaft 22 rotates by a predetermined angle in the shaft hole 35, and the rotational force of the drive shaft 22 is applied to the drive gear. 26 so that it can be transmitted to H.26. As shown in FIGS. 3 and 5, the driven gear 27 has a shaft hole 38 formed substantially at the center thereof. The shaft hole 38 is formed in a substantially circular shape so that the cylindrical driven shaft 30 is rotatably inserted.

  As shown in FIG. 5, the driving gear 26 and the driven gear 27 are accommodated in the first accommodating portion 24 and the second accommodating portion 25 in a state of being engaged with each other. A suction chamber 39 and a discharge chamber 40 defined by the drive gear 26 and the driven gear 27 are formed in the storage chamber 23. A space surrounded by the drive gear 26, the driven gear 27, and the suction portion 23a is a suction chamber 39, and ink that flows from the outside of the gear pump 20 is temporarily stored. A space surrounded by the drive gear 26 and the driven gear 27 and the discharge portion 23 b is a discharge chamber 40, and the ink sent from the suction chamber 39 by the rotation of the drive gear 26 and the driven gear 27 is temporarily stored. .

Further, the drive gear 26 is positioned by its tooth tip abutting against the side surface S <b> 1 of the first housing portion 24 (inside the housing chamber 23). And the front-end | tip part 22a of the drive shaft 22 is inserted by the shaft hole 35 of the positioned drive gear 26. As shown in FIG. As described above, the shaft hole 35 is formed so as to be larger than the outer diameter of the distal end portion 22 a of the drive shaft 22, so that the shaft hole 35 and the distal end of the drive shaft 22 fitted into the shaft hole 35 are inserted. A gap C1 is provided between the portion 22a. The gap C1 eliminates the deviation generated between the position of the shaft hole 28 of the housing 21 and the position of the shaft hole 35 of the drive gear 26. That is, the drive gear 26 is not positioned by the drive shaft 22 but is positioned by the side surface S <b> 1 of the first housing portion 24. For this reason, the shaft hole 28 of the housing 21 and the shaft hole 35 are likely to be displaced due to a molding error or the like, but the shaft hole 35 is formed to be larger by the gap C1. The drive shaft 22 fitted in the shaft 28 can absorb the deviation in the shaft hole 35. Thus, the drive shaft 22 fitted in the shaft hole 35 cannot be pulled out with respect to the drive gear 26 when the sealing ring R (see FIGS. 3 and 4) is attached to the tip 22a. It is connected.

  Further, the driven gear 27 is positioned by its tooth tip abutting against the side surface S <b> 2 of the second housing part 25 (inside the housing chamber 23). The driven shaft 30 is rotatably inserted into the shaft hole 38 of the positioned driven gear 27, and the lower end of the driven shaft 30 is supported by the shaft support portion 29 of the housing 21. As described above, the shaft support portion 29 is formed so that the inner diameter thereof is larger than the outer diameter of the driven shaft 30, so that the driven shaft 30 is located between the shaft support portion 29 and the shaft support portion 29 as shown in FIG. Are inserted in a state where a gap C2 is provided. The gap C <b> 2 eliminates the deviation that occurs between the shaft support portion 29 of the housing 21 and the driven shaft 30 of the driven gear 27. That is, the driven gear 27 is not positioned by the driven shaft 30 but is positioned by contacting the side surface S <b> 2 of the second housing portion 25. For this reason, a deviation is likely to occur between the shaft support portion 29 of the housing 21 and the driven shaft 30 fitted in the driven gear 27 due to a molding error or the like, but the driven shaft 30 is larger by the gap C2. The shift is absorbed in the formed shaft support portion 29. Further, a pressing spring 45 as a biasing means is press-fitted into the groove portion 31. The holding spring 45 is formed in a substantially U shape, and urges the driven shaft 30 fitted into the driven gear 27 accommodated in the second accommodating portion 25 in the direction opposite to the discharge chamber 40 side.

  The housing 21 that houses the drive gear 26 and the driven gear 27 is sealed by a cover 32 as a sealing plate. As shown in FIG. 3, the cover 32 includes a suction port 41 and a discharge port 42 that protrude toward the side surface 32 a, and center holes 41 a and 42 a are formed through the suction port 41 and the discharge port 42. Yes. These center holes 41 a and 42 a are formed so as to correspond to the positions of the suction chamber 39 and the discharge chamber 40 when the cover 32 seals the housing 21. The tube 13 communicated with the cap member 12 is connected to the suction port 41, and the ink discharged from the cap member 12 flows into the suction chamber 39 in the gear pump 20 through the suction port 41. The discharge port 42 is connected to the tube 15 communicating with the waste ink tank 16, and the ink in the discharge chamber 40 is sent out to the waste ink tank 16 through the discharge port 42. Further, four protrusions 55 are formed on one side surface 32 a of the cover 32. The protrusion 55 is formed in a circular shape and is pressed against a cover pressing spring 53 described later.

  As shown in FIG. 4, a press-fit groove 47 is formed on the other side surface 32 b of the cover 32. An annular seal member 48 is press-fitted into the press-fit groove 47. The seal member 48 includes a flexible member such as an elastomer, and is in close contact with the housing 21 when the cover 32 is attached to the housing 21 to seal the storage chamber 23.

  Further, as shown in FIG. 4, a shaft support portion 44 is recessed in the other side surface 32 b of the cover 32. The shaft support portion 44 supports the other end of the driven shaft 30 of the driven gear 27, similarly to the shaft support portion 29 formed in the housing 21. Since the inner diameter of the shaft support portion 44 is larger than the outer diameter of the driven shaft 30 of the driven gear 27 in the same manner as the shaft support portion 29, the driven shaft 30 is spaced from the shaft support portion 44 by a gap C3 (see FIG. 5). Inserted. Further, a groove portion 43 is continuously formed in the shaft support portion 44 in the same manner as the shaft support portion 29 of the housing 21. A presser spring 46 as an urging means is press-fitted into the groove 43. The presser spring 46 is formed in a substantially U shape, and urges the driven shaft 30 fitted into the driven gear 27 accommodated in the second accommodating portion 25 in the direction opposite to the discharge chamber 40 side. .

Further, as shown in FIG. 2, a cover pressing spring 53 is attached from the upper side (one side 32 a side) of the cover 32. As shown in FIGS. 3 and 4, the cover pressing spring 53 is formed in a plate shape, and both ends thereof are bent toward the housing 21 side (the other side surface 53 b side). A hole H3 for penetrating the suction port 41 and the discharge port 42 of the cover 32 is formed in the approximate center of the cover pressing spring 53. Further, four spring portions 54 are formed in the cover pressing spring 53 by cutting four portions on both sides of the hole H3 into a substantially U shape. When these spring portions 54 are attached to the cover 32, the spring portions 54 are pushed up by the protrusions 55 of the cover 32 and bent toward the one side surface 53 a. Accordingly, the cover 32 is pressed against the housing 21 by being biased toward the housing 21 by the biasing force of the spring portion 54.

  Further, fitting insertion holes H <b> 1 and H <b> 2 are formed through the four corners of the cover 32 and the cover pressing spring 53. Four screws P that are inserted into the housing 21 are inserted into the insertion holes H1 and H2. Furthermore, a fastening member (not shown) such as a nut is attached to the screw P inserted into the insertion holes H1 and H2. Thereby, the cover 32 and the cover pressing spring 53 are fixed to the housing 21.

  Next, the operation of the gear pump 20 will be described by taking as an example the case where the recording head 8 is cleaned. During head cleaning, the cap holder 11 is driven to seal the nozzle forming surface of the recording head 8 with the cap member 12. When a predetermined timing drive command is sent from a control unit (not shown) of the printer 1, the drive motor is driven and the drive shaft 22 rotates in the r1 direction. When the drive shaft 22 rotates in the r1 direction, the tip 22a of the drive shaft 22 engages with the shaft hole 35 of the drive gear 26, so that the drive gear 26 rotates in the r1 direction. The driven gear 27 rotates in the r2 direction by meshing with the drive gear 26.

  When the drive gear 26 and the driven gear 27 are rotated, the ink stored in the suction chamber 39 is confined in a space formed by each tooth groove and the side surfaces S1 and S2 of the storage chamber 23, and sequentially sent out to the discharge chamber 40 side. It is. For this reason, the suction chamber 39 is in a low pressure state. As a result, due to the pressure difference between the suction chamber 39 and the cap member 12, the ink and air in the cap member 12 flow into the suction chamber 39 through the tube 13. At this time, since the ink that has flowed in is sequentially sent out to the discharge chamber 40 side, the pressure in the suction chamber 39 is always low. The discharge chamber 40 to which ink is sent out is in a state where the pressure is higher than that of the suction chamber 39.

  Therefore, when the drive gear 26 and the driven gear 27 are rotated, the low-pressure ink in the suction chamber 39 is confined in the space formed by the tooth gap and the side surfaces S1 and S2 of the storage chamber 23, and is sent to the discharge chamber 40 side. It is done. For this reason, when the tooth tip of the driven gear 27 is separated from the end portion 25 a (see FIG. 5) of the side surface S <b> 2 of the second housing portion 25, a pressure difference is generated between the space and the discharge chamber 40. As a result, a rapid ink flow is likely to occur in the vicinity of the discharge chamber 40, but the driven shaft 30 is urged in the opposite direction to the discharge chamber 40 side by the pressing springs 45 and 46, and thus the shaft support portion 29. , 44 is difficult to move. On the other hand, since the drive gear 26 is engaged with the drive shaft 22, the movement toward the discharge chamber 40 is restricted by the friction of the engagement portion.

According to the above embodiment, the following effects can be obtained.
(1) In the above embodiment, the drive gear 26 is positioned by contacting the side surface S1 of the first housing portion 24 formed in the housing 21. Further, the shaft hole 35 is formed so as to be larger than the outer diameter of the distal end portion 22a of the drive shaft 22, and the drive shaft 22 is fitted into the shaft hole 35 with a gap C1. That is, when a deviation due to a molding error or the like occurs between the shaft hole 28 and the shaft hole 35 of the housing 21, the shaft hole 28 does not have a large gap between the drive gear 26 and the side surface S 1. When the inserted drive shaft 22 absorbs the deviation in the shaft hole 35, the drive gear 26 and the side surface S1 come into contact with each other and are positioned. Therefore, the drive shaft 22 can be fitted into the shaft hole 28 of the housing 21 and the shaft hole 35 of the drive gear 26 without processing the drive gear 26 and the housing 21 with high accuracy. Further, since it is not necessary to provide a large gap between the drive gear 26 and the side surface S1, it is possible to ensure the sealing performance of the space formed by the tooth groove of the drive gear 26 and the side surface S1. That is, the gear pump 2
Pump performance can be improved without processing 0 with high accuracy.

  (2) In the above embodiment, the driven gear 27 is positioned by contacting the side surface S <b> 2 of the second accommodating portion 25 formed in the housing 21. In addition, shaft support portions 29 and 44 for supporting the driven shaft 30 inserted into the driven gear 27 are formed to be larger than the outer diameter of the driven shaft 30, and the driven shaft 30 is spaced from the shaft support portions 29 and 44. C2 and C3 were provided and inserted. That is, when a deviation occurs due to a molding error or the like between the driven shaft 30 and the shaft support portions 29 and 44 of the housing 21, a large gap is formed between the driven gear 27 and the side surface S <b> 2 of the second housing portion 25. Even if not provided, the driven shaft 30 absorbs the deviation in the shaft support portions 29 and 44, whereby the driven gear 27 and the side surface S2 come into contact with each other and are positioned. For this reason, the driven shaft 30 can be fitted and inserted without processing the driven gear 27 and the housing 21 with high accuracy. In addition, since it is not necessary to provide a large gap between the driven gear 27 and the side surface S2, it is possible to ensure the sealing property of the space formed by the tooth groove of the driven gear 27 and the side surface S2. That is, the pump performance can be improved without processing the gear pump 20 with high accuracy.

  (3) In the above embodiment, the groove portions 31 and 43 are formed continuously to the shaft support portions 29 and 44 that support the driven shaft 30 of the driven gear 27. Further, presser springs 45 and 46 are press-fitted into the grooves 31 and 43, respectively. Then, the presser springs 45 and 46 urge the driven shaft 30 in the direction opposite to the discharge chamber 40 side. For this reason, even if the tooth tip of the driven gear 27 is separated from the end portion 25a of the side surface S2 of the second storage portion 25 and the ink stored in the tooth groove is about to be discharged, the pressing springs 45 and 46 are biased. Therefore, the displacement of the driven shaft 30 can be prevented. That is, even when the driven shaft 30 is inserted with the clearances C2 and C3 provided in the shaft support portions 29 and 44 of the housing 21, the vibration of the driven gear 27 can be prevented.

In addition, you may change this embodiment as follows.
In the above embodiment, the biasing means is a substantially U-shaped presser spring, but if the driven gear 27 can be biased in the direction opposite to the discharge chamber 40 side, such as a simple compression spring, leaf spring, etc. Anything

  In the above embodiment, the drive gear 26 and the driven gear 27 are positioned on the side surfaces S1 and S2 of the storage chamber 23. The drive gear 26 is configured such that the drive shaft 22 is inserted into the shaft hole 35 with a gap C1. In addition, the driven gear 27 is configured such that the driven shaft 30 is inserted with clearances C2 and C3. In addition, either one of the gears may be positioned by the side surfaces S1 and S2.

  In the above-described embodiment, the pressure springs 45 and 46 that urge the driven gear 27 in the direction opposite to the discharge chamber 40 side are disposed in the gear pump 20. These holding springs 45 and 46 may be used as urging means for urging the drive gear 26. In this case, a groove is formed in the shaft hole 28 of the housing 21, and a pressing spring is press-fitted into the groove.

  In the above embodiment, the gear pump 20 is mounted on the so-called off-carriage type printer 1 in which the ink cartridge 10 is not mounted on the carriage 5. In addition, the gear pump 20 may be mounted on a printer of a type in which an ink cartridge is mounted on a carriage. Moreover, you may use the gear pump 20 as a pump mounted in apparatuses other than a liquid ejecting apparatus.

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 illustrating a printer according to the invention. The perspective view of the gear pump with which the printer is equipped. The exploded perspective view of the gear pump. The exploded perspective view of the gear pump. The top view explaining the inside of the gear pump. The top view explaining the inside of the gear pump. Conventional gear pump.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Printer as a liquid ejecting apparatus, 20 ... Gear pump, 21 ... Housing, 22 ... Drive shaft, 23 ... Storage chamber, 26 ... Drive gear, 27 ... Driven gear, 29, 44 ... Shaft support part, 30 ... Driven shaft, 32 ... Cover as sealing plate, 35 ... Shaft hole, 45, 46 ... Pressing spring as urging means, C1, C2, C3 ... Gap, S1, S2 ... Side face as inside of storage chamber.

Claims (5)

A drive gear and a driven gear are housed in a housing chamber provided in the housing, and a drive shaft that is fitted and supported in a shaft hole formed in the housing is connected to the shaft hole of the drive gear, and according to the rotation of the drive shaft In the gear pump in which the teeth of the driving gear and the driven gear are rotated so as to be in sliding contact with the inside of the storage chamber,
The shaft hole of the drive gear is formed in a shape that drives and connects the drive shaft with a gap. A shaft support portion in which a drive gear and a driven gear are housed in a housing chamber provided in the housing, the housing chamber is sealed with a sealing plate, and a driven shaft of the driven gear is formed on the housing and the sealing plate. In a gear pump that is inserted into and rotated so that the teeth of the drive gear and the driven gear are in sliding contact with the inside of the storage chamber,
The shaft support part is formed in a shape that fits the driven shaft with a gap. The gear pump according to claim 2,
A gear pump, wherein a biasing means for biasing the driven shaft to a reference position is provided in a gap between the shaft support portion and the driven shaft. The gear pump according to claim 3,
The gear pump according to claim 1, wherein the biasing means biases the driven shaft of the driven gear in a direction opposite to the liquid discharge side. A liquid ejecting apparatus comprising the gear pump according to claim 1.

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