JP2005186487A - Pump unit and liquid ejector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump unit in which sticking of liquid is eliminated at the time of starting operation, and to provide a liquid ejector equipped with that pump unit. <P>SOLUTION: When a motor M is driven to turn a drive shaft Ma anticlockwise under a second state where a third coupling member 32 is coupled with a fourth coupling member 33, the driving force is transmitted sequentially to a pinion gear PG (anticlockwise) to a second helical gear HG2 (clockwise) to the third and fourth coupling members 32 and 33 (clockwise) to a shaft 34 (clockwise) to a second coupling gear CG2 (clockwise) to a first coupling gear CG1 (anticlockwise) to a drive haft 23 (anticlockwise). Consequently, the drive gear of the gear pump GP rotates with a large torque. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  Conventionally, an ink jet recording apparatus is widely known as one of liquid ejecting apparatuses. In this ink jet recording apparatus, ink stored in an ink cartridge is supplied to a recording head via an ink flow path. Then, the supplied ink is ejected from the nozzles formed on the recording head toward the recording medium to form dots to perform recording.

  In general, in this ink jet recording apparatus, in order to reduce ink ejection defects, bubbles, thickened ink, and the like are forcibly sucked from the ink flow path or nozzles by cleaning that applies negative pressure to the nozzles of the recording head as appropriate. Was discarded in the waste ink tank. As a mechanism for generating such a negative pressure, various ink jet recording apparatuses including a pump unit have been proposed. (For example, Patent Document 1).

The ink jet recording apparatus described in Patent Document 1 includes a pump unit including a motor and a gear pump. A cap member is connected to the ink suction port of the gear pump via a suction tube. Further, a waste ink tank is connected to the ink discharge port of the gear pump via a waste ink tube. Then, by transmitting the driving force from the motor to the two gears provided in the pump casing of the gear pump, the gears are rotated to apply a negative pressure to each nozzle of the recording head via the cap member. be able to. The ink sucked from each nozzle by this negative pressure flows into the gear pump from the cap member through the suction tube and the ink suction port, and then is discharged to the waste ink tank through the waste ink tube and the ink discharge port. Further, by configuring the motor as a DC motor or a stepping motor, it is easy to control the number of rotations of the gear pump and select the ink suction amount of the gear pump.
JP-A-6-328730

  However, in the ink jet recording apparatus described in Patent Document 1, when the ink jet recording apparatus remains unused for a long period of time, the ink remaining in the gear pump may dry out and adhere to the gear. . Therefore, when the ink jet recording apparatus is started from a long unused state, the load on the gear in the gear pump has increased. For this reason, the rotational speed of the gear in the gear pump is reduced, the negative pressure applied to the cap member is reduced, and the cleaning effect by the pump unit may be reduced.

  On the other hand, in order to prevent the gear pump from being affected by the sticking of the ink, it is necessary to transmit a driving force exceeding the load to the gear. As a solution to this, there is a method of increasing the output by enlarging the motor. However, if the motor becomes large, it will lead to an increase in the size of the pump unit composed of the motor, and an ink jet that has recently been requested. This will cause an adverse effect on the downsizing of the recording apparatus.

  SUMMARY An advantage of some aspects of the invention is that it provides a pump unit that eliminates the sticking of liquid during start-up and a liquid ejecting apparatus including the pump unit. .

  The pump unit of the present invention accommodates a drive motor, a drive gear, and a driven gear engaged with the drive gear and driven in the pump chamber, and sucks fluid from the inlet based on the rotation of the drive gear, A pump unit comprising: a gear pump that flows out the sucked fluid from the outlet; and a first torque transmission mechanism that rotates the drive gear by applying a first drive torque based on the drive force of the drive motor. A second torque transmission mechanism that rotates by applying a second driving torque larger than the first driving torque based on the driving force of the driving motor, the first torque transmission mechanism, And switching means for selecting one of the second torque transmission mechanisms and transmitting the driving force of the drive motor to the drive gear via the selected torque transmission mechanism.

  According to this, the driving force of the driving motor is transmitted to the driving gear as the first driving torque and the second driving torque larger than the first driving torque. By receiving the first and second driving torques, the driving gear rotates, and the driven gear can also rotate accordingly. Therefore, for example, when the fluid dries in the pump chamber of the gear pump and adheres to the drive gear or the driven gear, the second torque transmission mechanism is selected by the switching means, so that the second drive gear is selected. The driving torque and the driven gear can be transmitted to rotate the driving gear and the driven gear to peel off the fluid adhering portion. Then, after the liquid fixing portion is peeled off, by selecting the first torque transmission mechanism, the first drive torque can be transmitted to the drive gear and rotated more quickly. As a result, when the pump unit is started from the unused state for a long period of time, the load applied to the drive gear and the driven gear can be reduced, thereby preventing a reduction in the rotational speed of the drive and driven gear in the gear pump. It is possible to prevent a reduction in suction effect by the gear pump.

  In the pump unit, the first torque transmission mechanism includes a drive shaft connected to the drive gear, and a first helical gear that rotates in mesh with a pinion gear that is rotatably supported by the drive shaft and connected to the drive motor. The second torque transmission mechanism includes a first gear fixed to the drive shaft of the drive gear, a support shaft, and a second gear fixed to the support shaft and meshed with the first gear. And a second helical gear that is rotatably supported on the support shaft and meshes with the pinion gear, and the switching means is provided on the drive shaft, and is based on the direction of rotation of the pinion gear. A first engagement / disengagement member that guides the first helical gear to two positions, ie, a coupling position for coupling with the drive shaft and a non-coupling position for coupling, and a rotation direction of the pinion gear. Said second helical gear based on, and a second engaging and disengaging member for guiding the 2 position of the non-coupling position of the coupling position and a non-coupling for coupling with respect to the support shaft.

  According to this, for example, when the first helical gear is connected to the drive shaft by the first engagement / disengagement member, the driving force from the drive motor is transmitted in the order of pinion gear → first helical gear → drive shaft. The drive gear can be rotated. For example, when the second helical gear is connected to the support shaft by the second engaging / disengaging member, the driving force from the drive motor is as follows: pinion gear → second helical gear → support shaft → second gear → second gear The drive gear can be rotated in the order of 1 gear → drive shaft. Then, by changing the rotation direction of the pinion gear by the drive motor, it is possible to select the connected state or the non-connected state of the first and second engaging / disengaging members. As a result, since the second drive torque can be transmitted to the drive gear of the gear pump without increasing the size of the drive motor, the pump unit can be reduced in size.

In the pump unit, the first torque transmission mechanism includes a drive shaft connected to the drive gear and a first rotating gear fixed to the drive shaft, and the second torque transmission mechanism includes the drive shaft. A second rotation gear fixed to the drive shaft of the gear; a support shaft; a third rotation gear fixedly or rotatably supported on the support shaft and meshed with the second rotation gear; The switching means comprises a sun gear coupled to the drive motor and a planetary gear meshing with the sun gear, and the planetary gear is based on the direction of rotation of the sun gear. Is configured to mesh with either the first rotating gear or the fourth rotating gear.

  According to this, for example, when the planetary gear meshes with the first rotation gear, the driving force from the drive motor is transmitted in the order of sun gear → planetary gear → first rotation gear → drive shaft. Can be rotated. For example, when the planetary gear meshes with the fourth rotation gear, the driving force from the drive motor is as follows: pinion gear → planetary gear → fourth rotation gear → third rotation gear → second rotation gear → The drive gear can be rotated in the order of the drive shaft. And the meshing of the planetary gear can be selected by changing the rotation direction of the sun gear and the planetary gear by the drive motor. As a result, since the second drive torque can be transmitted to the drive gear of the gear pump without increasing the size of the drive motor, the pump unit can be reduced in size.

  In this pump unit, the first torque transmission mechanism is a drive shaft connected to the drive gear, and the second torque transmission mechanism is a first rotation gear fixed to the drive shaft, and a support shaft. And a second rotation gear that is fixedly or rotatably supported on the support shaft and meshes with the first rotation gear, and the switching means is configured to rotate the drive shaft based on rotation in one direction of the drive motor. A first one-way clutch for transmitting and a second one-way clutch for transmitting rotation based on rotation in the other direction of the drive motor to the support shaft.

  According to this, for example, when the drive motor rotates in one direction, the drive force is transmitted in the order of the first one-way clutch → the drive shaft, and the drive gear can be rotated. For example, when the drive motor is rotating in the other direction, the driving force is transmitted in the order of the second one-way clutch → the support shaft → the second rotation gear → the first rotation gear → the drive shaft. The drive gear can be rotated. Therefore, the first or second drive torque can be transmitted to the drive gear by causing the drive motor to rotate in one direction or the other direction. As a result, since the second drive torque can be transmitted to the drive gear of the gear pump without increasing the size of the drive motor, the pump unit can be reduced in size.

  The liquid ejecting apparatus of the present invention includes the pump unit of the present invention, the liquid ejecting head that ejects the liquid, the pump unit that cleans the liquid ejecting head, and the liquid ejecting head that discharges through the pump unit. A waste liquid storage mechanism for storing the liquid to be stored and a load torque detection means for detecting the load torque of the pump unit, wherein the switching means detects the load torque of the pump unit by the load torque detection means. When the load torque is large, the second torque transmission mechanism is selected. When the load torque is small, the first torque transmission mechanism is selected and the driving force of the drive motor is supplied to the drive gear. Configured to communicate.

According to this, when the liquid dries in the pump chamber of the gear pump and adheres to the drive gear or the driven gear, the second drive torque is applied to the drive gear by selecting the second torque transmission mechanism. Transmission and rotation of the drive gear and the driven gear can peel off the liquid fixing portion. Then, after the liquid fixing part is peeled off, the first torque transmission mechanism is selected and the first torque is transmitted to the drive gear, whereby the drive gear can be rotated more quickly. As a result, when the liquid ejecting apparatus is started from an unused state for a long period of time, the load on the drive gear and the driven gear of the gear pump can be reduced, so that the rotational speed of the drive and driven gear in the gear pump can be reduced. A drop can be prevented, and a reduction in suction effect by the gear pump can be prevented.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
FIG. 1 is a plan view for explaining the outline of the printer of this embodiment.
As shown in FIG. 1, a printer 1 as a liquid ejecting apparatus includes a substantially rectangular frame 2. The frame 2 is provided with a platen 3 in the longitudinal direction, and recording paper 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 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 a carriage 5 is drivingly connected to the carriage motor 6 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. In response to this driving force, the carriage 5 is guided by the guide member 4 and reciprocates in parallel (main scanning direction) with the platen 3.

  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 so as to face the recording paper, and this nozzle forming surface has a nozzle row (n is a natural number) consisting of n nozzles (n is a natural number). 6 rows are formed.

  In this embodiment, for convenience of explanation, six nozzle rows each including n nozzles are formed. However, the number of nozzles and the number of nozzle rows per row are not limited to this, and may be changed as appropriate. Also good.

  As shown in FIG. 1, the frame 2 is provided with a cartridge case 9, and an ink cartridge 10 as a liquid storage unit is detachably loaded in the cartridge case 9. Ink cartridges 10 store ink as fluids of corresponding colors (in this embodiment, black B, cyan C, magenta MG, yellow Y, light cyan LC, and light magenta LM).

  The ink stored in these ink cartridges 10 is supplied to the recording head 8 via tubes T1 to T6 by being pressurized by a pressure pump (not shown). That is, the printer 1 is a so-called off-carriage type.

  The ink flowing into the recording head 8 is pressurized by a piezoelectric element (not shown) and ejected as ink droplets from the nozzles of the recording head 8 to form dots. That is, black B, cyan C, magenta MG, yellow Y, light cyan LC, and light magenta LM, which are corresponding colors, are ejected from the nozzles formed in the recording head 8, respectively.

  In the printer 1, an area for printing by ejecting ink droplets onto a recording sheet while reciprocating the carriage 5 is used as a printing area. Further, the printer 1 is provided with a non-printing area for sealing the nozzles during non-printing, and a cap holder 11 is provided in the non-printing area as shown in FIG.

As shown in FIG. 1, the cap holder 11 is provided with a flexible cap member 12 so as to face the nozzle forming surface of the recording head 8. The cap holder 11 seals each nozzle by bringing the cap member 12 into close contact with the nozzle forming surface via a drive mechanism (not shown). The cap holder 11 is formed with a suction port (not shown) communicating with the cap member 12 at the bottom, and the suction port is connected to the pump unit 14 via the tube 13. Further, a waste ink tank 16 is connected to the pump unit 14 via a tube 15.

The pump unit 14 applies a negative pressure to the cap member 12 through the tube 13 as will be described later.
That is, when the nozzle is sealed by the cap member 12, the pump unit 14 is operated to apply a negative pressure in the space formed by the cap member 12 and the nozzle forming surface of the recording head 8. As a result, so-called cleaning can be performed in which ink and bubbles with increased viscosity in the nozzle, ink and dust adhering to the nozzle forming surface are sucked out. The ink sucked from the recording head 8 is discharged to the waste ink tank 16 via the pump unit 14.

Next, the configuration of the pump unit 14 will be described with reference to FIGS.
As shown in FIG. 2, the pump unit 14 includes a motor M, a gear pump GP, and a gear mechanism 20.

  In the pump unit 14, the gear pump GP is driven by transmitting the driving force from the motor M to the gear pump GP via the gear mechanism 20. As shown in FIGS. 3 and 4, the gear pump GP includes a substantially rectangular main body case 21, and the main body case 21 is formed of an upper case 21a and a lower case 21b. A pump chamber 22 is recessed in the lower case 21b. In the pump chamber 22, the drive gear G <b> 1 and the driven gear G <b> 2 are accommodated so as to be able to rotate while meshing with each other. Then, by attaching the upper case 21a to the lower case 21b, the main body case 21 seals the pump chamber 22 that houses the drive gear G1 and the driven gear G2. A drive shaft 23 is attached to the drive gear G1 accommodated in the pump chamber 22 so as to penetrate from the outside of the main body case 21 (lower case 21b). As shown in FIG. 2, a motor M is drivingly connected to the driving shaft 23 via a gear mechanism 20 outside the main body case 21. With this configuration, the driving force of the motor M is transmitted to the driving gear G1 via the gear mechanism 20.

  On the other hand, the driven gear G <b> 2 is inserted through a driven shaft 24 disposed in the main body case 21. The driven gear G2 meshes with the drive gear G1 as described above, and when the drive gear G1 rotates in the direction of the arrow in FIG. 3, it is driven to rotate in the direction of the arrow. With this configuration, the driving force of the motor M transmitted to the driving gear G1 is further transmitted to the driven gear G2. Then, in the pump chamber 22, the space of the pump chamber 22 where the teeth of the drive gear G1 and the driven gear G2 are separated from each other based on the fact that the drive gear G1 and the driven gear G2 mesh with each other and rotate in the direction of the arrows. The part is referred to as an introduction part S2. Further, the space portion of the pump chamber 22 where the teeth of the drive gear G1 and the driven gear G2 merge is defined as a lead-out portion S1.

Further, as shown in FIG. 4, the upper case 21a of the main body case 21 has a side surface (a surface opposite to the surface to which the gear mechanism 20 is connected), which is connected to the introduction portion S2 and the lead-out portion S1. Ink discharge ports 25 and ink suction ports 26 are respectively formed at corresponding positions. The ink discharge port 25 communicates with a lead-out portion S1 of the pump chamber 22 formed in the main body case 21. The ink suction port 26 communicates with an introduction portion S2 of the pump chamber 22 formed in the main body case 21. The tube 15 is connected to the ink discharge port 25, and the tube 13 is connected to the ink suction port 26. As a result, the pump unit 14 including the gear pump GP is connected to the cap member 12 and the waste ink tank 16 as described above.

  With this configuration, when the motor M is driven, the driving gear G1 and the driven gear G2 rotate in the directions of the arrows, respectively, receiving the driving force. Thus, the ink introduced from the ink suction port 26 into the introduction portion S2 of the pump chamber 22 is guided to the lead-out portion S1 of the pump chamber 22 by the drive gear G1 and the driven gear G2. The ink guided to the lead-out portion S1 is discharged to the ink discharge port 25. That is, a negative pressure is generated in the cap member 12, and the ink sucked from the cap member 12 through the tube 13 can be discarded into the waste ink tank 16 through the tube 15.

  On the other hand, the driving state of the motor M is detected by a sensor S (see FIGS. 5 and 6), and is driven and controlled in accordance with an electric signal output from a control circuit (not shown) provided in the printer 1. It has become. The control circuit is applied to the drive gear G1 and the driven gear G2 of the pump unit 14 based on a detection signal detected from the sensor S and a preset reference value for detecting the drive state of the motor M. The load torque is detected. Thus, the pump unit 14 supplies a negative pressure to the cap member 12 based on a control signal from the control circuit, and performs cleaning according to the load torque.

Next, the configuration of the gear mechanism 20 will be described with reference to FIGS.
As described above, the gear mechanism 20 transmits the driving force generated from the motor M to the driving shaft 23 of the gear pump GP, and rotates the driving gear G1 and the driven gear G2 of the gear pump GP (in the direction of the arrow shown in FIG. 3). It is for making it happen.

  2, 5 and 6, the gear mechanism 20 includes a pinion gear PG, first and second helical gears HG1, HG2, first and second connecting gears CG1, CG2, a support frame SF, a first frame The first to fourth connecting members 30 to 33 and the shaft 34 are provided.

  The pinion gear PG is a columnar gear that is directly connected to the drive shaft Ma (see FIGS. 5 and 6) of the motor M described above, and has the first and second helical gears HG1 at the outer edge thereof. , Teeth PG for meshing with HG2. When the motor M is driven, the pinion gear PG is configured to be rotatable forward and backward (in the direction of arrow A or arrow G shown in FIGS. 7 and 8) along the rotational direction of the drive shaft Ma. . The motor M of the present embodiment is configured such that the drive shaft Ma rotates clockwise when the motor M rotates forward, and the drive shaft Ma rotates counterclockwise when the motor M rotates counterclockwise.

  On the other hand, a connection gear CG1 is fixed to the drive shaft 23 of the gear pump GP outside the main body case 21 and on the side of the gear pump GP. Further, the first connecting member 30 is inserted through the drive shaft 23 so as to directly face the first connecting gear CG1.

  The first connecting member 30 is formed in a cylindrical shape, and by inserting the drive shaft 23 into the inner diameter portion thereof, rotation about the drive shaft 23 and the rotation along the drive shaft 23 are performed. Reciprocal movement (X direction and -X direction) is possible. Further, a support groove 30a is formed at the base end portion (the side directly facing the connection gear CG1) of the first connection member 30. The support groove 30a is configured to be fitted to a support member SFa that is formed to extend from the support frame SF. By fitting the support groove 30a to the support member SFa, the first connecting member 30 is driven. It is positioned and supported on the shaft 23. Further, a notch 30 b is formed at the other end of the first connecting member 30. Further, as will be described later, the support frame SF is guided by a guide rail (not shown) and can reciprocate in the X direction and the −X direction shown in FIGS. 5 and 6.

  On the other hand, the cylindrical second connecting member 31 is fixed to the end of the drive shaft 23 of the gear pump GP so that the reciprocating movement of the first connecting member 30 on the drive shaft 23 is restricted. It has become. The second connecting member 31 is formed with a notch 31b so as to face the notch 30b of the first connecting member 30 directly toward the gear pump GP. The notch 31b can be fitted to the notch 30b, and the first and second connecting members 30 and 31 are integrated by fitting the notches 30b and 31b to each other. It is configured as follows. With this configuration, when the cutout portions 30b and 31b of the first and second connecting members 30 and 31 are fitted and integrated with each other, the first connecting member 30 has its axis. When rotating in the center direction, the second connecting member 31 similarly rotates in the axial direction. At this time, as described above, since the second connecting member 31 is fixed to the drive shaft 23, the drive shaft 23 also rotates in the axial direction. When the drive shaft 23 rotates in the axial direction, the drive gear G1 and the driven gear G2 also rotate in the gear pump GP.

  Further, the first helical gear HG1 is fixed to the outer edge of the first connecting member 30. Teeth HG1a are formed on the outer surface of the first helical gear HG1, and the teeth HG1a mesh with the teeth PGa of the pinion gear PG. Therefore, when the motor M is driven and the drive shaft Ma rotates, for example, to the right, the pinion gear PG rotates to the right, and the first helical gear HG1 rotates to the left accordingly.

  That is, when the motor M is driven and the drive shaft Ma rotates clockwise while the first connecting member 30 is connected to the second connecting member 31, this driving force is generated by the pinion gear PG (right rotation) → Helical gear HG1 (left rotation) → first and second connecting members 30, 31 (left rotation) → drive shaft 23 (left rotation) are transmitted in this order. As a result, the drive gear G1 of the gear pump GP rotates (in the direction of the arrow shown in FIG. 3). Further, when the motor M is driven when the first and second connecting members 30 and 31 are not connected, only the first connecting member 30 including the first helical gear HG1 is mounted on the drive shaft 23. To idle.

  As shown in FIGS. 2, 5, and 6, the third connecting member 32 is formed in a cylindrical shape like the first connecting member 30, and has a support groove 32a at its base end. And a notch 32b (toward the gear pump GP) is formed at the other end. The third connecting member 32 is formed such that the support groove 32a is fitted to a support member SFb formed to extend from the support frame SF. Further, a cylindrical shaft 34 rotatably inserted by a support member (not shown) is inserted into the inner diameter portion of the third connecting member 32. Then, the third connecting member 32 is rotated around the same axis 34 as the axis 34 and reciprocating along the same axis 34 (the X direction and −) as with the first connecting member 30. X direction) is possible. At this time, the third connecting member 32 is positioned and supported on the shaft 34 by being fitted to the support member SFb.

  On the other hand, the second connecting gear CG2 is fixed to the shaft 34 at the base end (gear pump GP side). The second connection gear CG2 is a gear for connecting to the first connection gear CG1 fixed to the drive shaft 23, and the teeth of the second connection gear CG2 are connected to the first connection gear CG1. The teeth are connected to each other by meshing them. Further, the fourth connecting member 33 is fixed to the proximal end portion of the shaft 34 so as to be adjacent to the connecting gear CG2. The fourth connecting member 33 is formed with a notch 33 b so as to directly face the notch 32 b of the third connecting member 32. The notch 33b can be fitted with the notch 32b, and the third and fourth connecting members 32 and 33 are integrated by fitting the notches 32b and 33b together. It is configured as follows.

  With this configuration, when the notches 32b and 33b of the third and fourth connecting members 32 and 33 are fitted and integrated with each other, the third connecting member 32 has its axis. When rotating in the center direction, the fourth connecting member 33 similarly rotates in the axial direction. At this time, since the fourth connecting member 33 is fixed to the shaft 34 as described above, the coaxial 34 also rotates in the axial direction. When the shaft 34 rotates in the axial direction, the connection gear CG2 fixed to the coaxial 34 rotates, and accordingly, the first connection gear CG1 connected to the second connection gear CG2 also rotates. To do. As described above, since the first connection gear CG1 is fixed to the drive shaft 23 of the gear pump GP, the drive shaft 23 rotates in the axial direction along with the rotation of the connection gear CG1. As a result, the drive gear G1 and the driven gear G2 are also rotated in the gear pump GP.

  The second helical gear HG2 is fixed to the outer edge of the fourth connecting member 32. Teeth HG2a are formed on the outer surface of the second helical gear HG2, and the teeth HG2a mesh with the teeth PGa of the pinion gear PG. Accordingly, when the motor M is driven and the drive shaft Ma is rotated counterclockwise, for example, the pinion gear PG is also rotated counterclockwise, and accordingly, the second helical gear HG2 is rotated clockwise.

  That is, when the motor M is driven and the drive shaft Ma rotates counterclockwise in a state where the third connecting member 32 is connected to the fourth connecting member 33, the driving force is generated by the pinion gear PG (left rotation) → Second helical gear HG2 (right rotation) → third and fourth connecting members 32 and 33 (right rotation) → shaft 34 (right rotation) → second connection gear CG2 (right rotation) → first connection gear CG1 It is transmitted in the order of (left rotation) → drive shaft 23 (left rotation). As a result, the drive gear G1 of the gear pump GP rotates (in the direction of the arrow shown in FIG. 3). Further, when the motor M is driven when the third connecting member 32 and the fourth connecting member 33 are not connected, the connecting member 32 including the second helical gear HG2 idles on the shaft 34. .

  In the present embodiment, the ratio of the number of teeth of the pinion gear PG and the helical gears HG1 and HG2 is 1: 1: 2, and the ratio of the number of teeth of the coupling gears CG1 and CG2 is 3: 1.

  Accordingly, since the reduction ratio of the pinion gear PG and the helical gear HG1 is 1 (= the number of teeth of the helical gear HG1 / the number of teeth of the pinion gear PG), when the torque of 1 is generated in the pinion gear PG by the driving of the motor M, A torque of 1 is transmitted to the drive shaft 23 via HG1.

  The reduction ratio of the pinion gear PG and the helical gear HG2 is 2 (= the number of teeth of the helical gear HG1 / the number of teeth of the pinion gear PG), and the reduction ratio of the connection gears CG1 and CG2 is 3 (= the teeth of the connection gear CG1). Number / number of teeth of the connecting gear CG2). As a result, the total reduction ratio reaching the drive shaft 23 via the helical gear HG2 becomes 6 (= 2 × 3). Therefore, when 1 torque is generated in the pinion gear PG by driving the motor M, the helical gear HG2 is connected to the helical gear HG2. Six torques are transmitted to the drive shaft 23 via the gears CG1 and CG2.

That is, in the state where the third connecting member 32 and the fourth connecting member 33 are connected, the state is 6 times as large as the state where the first connecting member 30 and the second connecting member 31 are connected. Torque can be transmitted to the drive shaft 23. Moreover, in the state where the first connecting member 30 and the second connecting member 31 are connected, compared to the state where the third connecting member 32 and the fourth connecting member 33 are connected, The drive shaft 23 can be rotated six times faster with 1/6 of the torque transmitted to the drive shaft 23. And in this embodiment, as shown in FIG. 6, the state which the notch part 32b of the 3rd connection member 32 and the notch part 33b of the 4th connection member 33 have connected is shown in a 2nd state, FIG. As shown, the state where the notch 30b of the first connecting member 30 and the notch 31b of the second connecting member 31 are connected is referred to as a first state.

  Further, the teeth HG1a of the first helical gear HG1 and the teeth HG2a of the second helical gear HG2 are formed as right-hand threads, and the teeth PGa of the pinion gear PG are formed as left-hand threads so as to correspond thereto. Yes.

  With this configuration, when the motor M rotates forward and the pinion gear PG rotates clockwise (in the direction indicated by the arrow G in FIG. 8), as described above, the first and second helical gears HG1 are accordingly generated. , HG2 rotate counterclockwise (H arrow direction shown in FIG. 8 and anti-B arrow direction shown in FIG. 7). At this time, a thrust force is generated in the + X direction in the first and second helical gears HG1 and HG2. In response to this thrust force, the first and second helical gears HG1, HG2 move in the + X direction on the drive shaft 23 and the shaft 34, respectively. The support frame SF that supports the first and second helical gears HG1 and HG2 receives the thrust force together with the first and second helical gears HG1 and HG2 and moves in the + X direction.

  Further, when the motor M rotates in the reverse direction and the pinion gear PG rotates counterclockwise (in the direction of the arrow A shown in FIG. 7), the first and second helical gears HG1 and HG2 rotate clockwise (as shown in FIG. 8). Anti-H arrow direction and B arrow direction shown in FIG. At this time, a thrust force is generated in the −X direction in the first and second helical gears HG1 and HG2, and the first and second helical gears HG1 and HG2 move in the −X direction. . The support frame SF that supports the first and second helical gears HG1 and HG2 receives the thrust force together with the first and second helical gears HG1 and HG2 and moves in the −X direction.

  Therefore, when the motor M is rotated forward from the second state, the thrust force is generated in the + X direction, and the support frame SF and the first and second helical gears HG1 and HG2 move in the + X direction accordingly. Therefore, the connection of the third connecting member 32 and the fourth connecting member 33 is released. When the motor M is further rotated forward, the first connecting member 30 and the second connecting member 31 are connected to enter the first state. Further, when the motor M is rotated in the reverse direction from the first state, the thrust force is generated in the −X direction, and the support frame SF and the first and second helical gears HG1 and HG2 are accordingly moved in the −X direction. It moves and the connection of the 1st connection member 30 and the 2nd connection member 31 is cancelled | released. When the motor M is further rotated in the reverse direction, the third connecting member 32 and the fourth connecting member 33 are connected to be in the second state.

  That is, the pump unit 14 can be switched between the first state and the second state by rotating the motor M forward and backward. The torque transmitted to the drive shaft 23 of the gear pump GP is adjusted by switching between the first state and the second state.

Next, the operation of the pump unit 14 will be described with reference to FIGS.
First, the printer 1 is activated and the recording head 8 is cleaned. During normal use, as described above, the pump unit 14 drives the motor M to rotate forward from the second state (see FIG. 6). At this time, as shown in FIG. 8, the driving force is transmitted to the pinion gear PG through the drive shaft Ma, and the pinion gear PG rotates (rotates clockwise) in the direction of arrow G. In response to this, the first helical gear HG1 rotates (rotates counterclockwise) in the direction of the arrow H. Then, the motor M is further rotated forward to release the connection of the third and fourth connecting members 32 and 33 (release the second state), and then the first and second connecting members 30 and 31 are moved. Connected to the first state (see FIG. 5). As a result, the drive shaft 23 of the gear pump GP rotates (left rotation) in the direction of arrow F, and the drive gear G1 and the driven gear G2 of the gear pump GP rotate (in the direction of the arrow shown in FIG. 3). Then, the printer 1 stops this cleaning after a predetermined time. At this time, when 1 torque is generated from the motor M, 1 torque is applied to the drive shaft 23 of the gear pump GP, and the drive gear G1 and the driven gear G2 rotate accordingly. As a result, the drive gear G1 and the driven gear G2 of the gear pump GP can be driven at a speed six times that in the second state from the state where the ink fixing portion is peeled off.

  At this time, if it is detected that the load torque of the pump unit 14 is large, the motor M is rotated in the reverse direction. Then, the driving force is transmitted to the pinion gear PG via the driving shaft Ma. Accordingly, as shown in FIG. 7, the pinion gear PG rotates (rotates counterclockwise) in the direction of arrow A. Further, after releasing the connection between the first and second connecting members 30 and 31 (releasing the first state), the motor M is reversely rotated to connect the third and fourth connecting members 32 and 33. The second state (see FIG. 6) is set. As a result, the driving force from the motor M is transmitted to the second connection gear CG2 and rotates in the direction C arrow (rotates right), and accordingly, the first connection gear CG1 moves in the direction D arrow. Rotate (turn left). As a result, the drive shaft 23 of the gear pump GP rotates (left rotation) in the direction of arrow F, and the drive gear G1 and the driven gear G2 of the gear pump GP rotate (in the direction of the arrow shown in FIG. 3). At this time, when a torque of 1 is generated from the motor M, a torque of 6 is applied to the drive shaft 23 of the gear pump GP, and the drive gear G1 and the driven gear G2 rotate accordingly. At this time, if the ink is fixed in the main body case 21 of the gear pump GP, the fixed portion can be peeled off by the rotation of the drive gear G1 and the driven gear G2.

As mentioned above, according to this embodiment mentioned above, there exist the following effects.
(1) In this embodiment, the gear mechanism 20 of the pump unit 14 is driven in the first state, and when it is detected that the load torque of the pump unit 14 is large, the gear mechanism 20 is driven in the second state. . As a result, the gear pump GP of the pump unit 14 transmits a large torque to the drive shaft 23 in the second state when starting from the unused state for a long period of time, and slowly rotates the drive gear G1 and the driven gear G2. The ink fixing portion in the gear pump GP can be peeled off. Further, after the ink fixing portion is peeled off, a small torque is transmitted to the drive shaft 23 in the first state, and the drive pump G1 and the driven gear G2 can be rotated rapidly to drive the gear pump GP. That is, the pump unit 14 peels off the fixed portion of the ink in the gear pump GP, reduces the load on the drive gear G1 and the driven gear G2, and then rotates the drive gear G1 and the driven gear G2 quickly to thereby rotate the drive gear G1. And the fall of the rotational speed of the follower gear G2 can be prevented, and the fall of the suction force of the pump unit 14 can be reduced. As a result, in the pump unit 14, it is possible to prevent a reduction in the cleaning effect by the gear pump GP described above.
(2) In this embodiment, the support frame SF and the helical gears HG1 and HG2 are configured to reciprocate in the X direction and the −X direction by the thrust force. As a result, the motor M can be switched between the first state and the second state by forward and reverse rotation, so that the driving force (torque) transmitted to the driving gear G1 and the driven gear G2 can be transmitted without providing a special switching device. Can be adjusted. As a result, a large driving force (torque) can be transmitted to the gear pump GP without increasing the size of the motor M, and the ink fixing portion in the gear pump GP can be peeled off. Can be realized.
(Second Embodiment)
Next, a second embodiment embodying the present invention will be described with reference to FIGS.

In the present embodiment, for the sake of convenience of explanation, portions that are different from the first embodiment will be described, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.
As shown in FIG. 9, the pump unit 40 of this embodiment includes a gear pump GP, a motor M, and a gear mechanism 41 that are configured in the same manner as in the first embodiment. Unlike the first embodiment, the gear mechanism 41 does not include the support frame SF and the first and second helical gears HG1 and HG2.

  The gear mechanism 41 includes a first connecting gear CG1 fixed to the drive shaft 23 of the gear pump GP and a second connecting gear CG2 fixed to the shaft 34, as in the first embodiment. A gear 42 is fixed to the drive shaft 23 so as to be adjacent to the first connecting gear CG1 on the motor M side. A gear 43 is fixed to the second connecting gear CG2 so as to be adjacent to the second connecting gear CG2 on the motor M side, and the gear 43 is inserted into the shaft 34. .

  On the other hand, the planetary gear 44 meshes with the sun gear SG fixed to the drive shaft Ma (see FIGS. 10 and 11) of the motor M. The planetary gear 44 constitutes a planetary gear mechanism with the sun gear SG by being sandwiched between two pairs of support members 45 rotatably attached to the drive shaft Ma. With this configuration, when the motor M is driven in the forward direction and the sun gear SG rotates in the right direction (G arrow direction shown in FIG. 10), the planetary gear 44 rotates in the left direction (J arrow direction shown in FIG. 10). It is supposed to be. At this time, the planetary gear 44 rotates in the right direction (+ Y direction shown in FIG. 11) with the drive shaft Ma of the motor M as the rotation center while being supported by the support member 45. Further, when the motor M is driven in the reverse direction and the sun gear SG rotates counterclockwise (in the direction of arrow A shown in FIG. 11), the planetary gear 44 rotates in the clockwise direction (in the direction of arrow I shown in FIG. 11). . At this time, the planetary gear 44 is rotated in the left direction (the −Y direction shown in FIG. 10) with the drive shaft Ma of the motor M as the rotation center while being supported by the support member 45. By rotating in this way, the planetary gear 44 can mesh with either the gear 42 or the gear 43 by rotating the motor M forward and backward. In this embodiment, as shown in FIG. 10, the state where the gear 43 and the planetary gear 44 are engaged is the second state, and as shown in FIG. 11, the state where the gear 42 and the planetary gear 44 are engaged. The first state is assumed.

  In this second state, the driving force from the motor M is as follows: sun gear SG (right rotation, G arrow direction) → planetary gear 44 (left rotation, J arrow direction) → gear 43 (right rotation, K arrow direction) → second It is transmitted in the order of connection gear CG2 (right rotation, direction C arrow) → first connection gear CG1 (left rotation, direction D arrow) → drive shaft 23 (left rotation, direction F arrow). In the first state, the driving force from the motor M is as follows: sun gear SG (left rotation, A arrow direction) → planetary gear 44 (right rotation, I arrow direction) → gear 42 (left rotation, L arrow direction) → drive It is transmitted in order with the shaft 23 (left rotation, F arrow direction). Thus, in both the first state and the second state, the drive gear G1 of the gear pump GP can be rotated in the direction of the arrow shown in FIG.

  In the present embodiment, the ratio of the number of teeth of the sun gear SG and the planetary gear 44 is 1: 2, and the reduction ratio of the sun gear SG and the planetary gear 44 is 2. Further, the ratio of the number of teeth of the gear 43 and the planetary gear 44 is 1: 1, and the reduction ratio of the gear 43 and the planetary gear 44 is 1. The ratio of the number of teeth of the gear 42 and the planetary gear 44 is 1: 1.5, and the reduction ratio of the gear 43 and the planetary gear 44 is 1.5. On the other hand, the ratio of the number of teeth of the connection gear CG1 and the connection gear CG2 is 3: 1, and the reduction ratio of the connection gear CG1 and the connection gear CG2 is 3. Accordingly, in the second state, the total reduction ratio is 6 (= 2 × 1 × 3), and in the first state, the total reduction ratio is 3 (= 2 × 1.5).

By configuring in this way, the pump unit 40 is detected that the load torque of the pump unit 40 is large when being driven in the first state, similarly to the pump unit 14 of the first embodiment. Then, a large torque is transmitted to the drive shaft 23 in the second state. Accordingly, the drive gear G1 and the driven gear G2 can be slowly rotated to peel off the ink fixing portion in the gear pump GP. Then, after peeling off the ink fixing portion, a small torque is transmitted to the drive shaft 23 in the first state, and the gear pump GP can be driven by rotating the drive gear G1 and the driven gear G2 quickly. That is, the pump unit 40 peels off the ink adhering portion in the gear pump GP, reduces the load on the drive gear G1 and the driven gear G2, and then rotates the drive gear G1 and the driven gear G2 quickly, thereby reducing the suction force. Reduction can be reduced. As a result, in the pump unit 40, it is possible to prevent the above-described reduction in the cleaning effect by the gear pump GP when starting from an unused state for a long period of time.

As mentioned above, according to this embodiment mentioned above, in addition to the effect of 1st Embodiment, there exist the following effects.
(3) In the present embodiment, the planetary gear 44 is sandwiched between the two pairs of support members 45 to constitute the sun gear SG and the planetary gear mechanism. Thus, the gear mechanism 41 can be switched between the first state and the second state by rotating the motor M forward and backward. As a result, since the support frame SF and the first and second helical gears HG1 and HG2 are not provided as in the first embodiment, the pump unit 40 can be configured in a smaller space and the printer 1 can be downsized. can do.
(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.

In this embodiment, for the sake of convenience of explanation, portions different from those in the first and second embodiments will be described, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.
As shown in FIG. 12, the pump unit 50 of the present embodiment includes a gear pump GP, a motor M, and a gear mechanism 51 that are configured in the same manner as in the first embodiment. Unlike the first embodiment, the gear mechanism 51 does not include the support frame SF and the first and second helical gears HG1 and HG2.

  The gear mechanism 51 includes a first connecting gear CG1 fixed to the drive shaft 23 of the gear pump GP and a second connecting gear CG2 fixed to the shaft 34, as in the first embodiment.

  A first one-way clutch 52 is connected to the drive shaft 23 on the motor M side, and a shaft 53 is connected to the one-way clutch 52. A gear 54 is fixed to the end portion (motor M side) of the shaft 53. The first one-way clutch 52 transmits driving force to the driving shaft 23 of the gear pump GP, and rotates the driving gear G1 and the driven gear G2 in the gear pump GP as described above (in the direction of the arrow shown in FIG. 3). It is intended to rotate. Only when the gear 54 rotates counterclockwise and the shaft 53 rotates counterclockwise when viewed from the motor M side, the driving force is transmitted to the driving shaft 23 to rotate the driving shaft 23 counterclockwise.

  On the other hand, a second one-way clutch 55 is connected to the shaft 34 on the motor M side, and the motor M is connected to the one-way clutch 55 via a pinion gear PG to which a gear 56 is fixed. The second one-way clutch 55 transmits driving force to the second connecting gear CG2 and rotates the connecting gear CG2 clockwise as viewed from the motor M side. Only when the pinion gear PG rotates to the right, the driving force is transmitted to the shaft 34 to rotate the connecting gear CG2 to the right. The gears 54 and 56 mesh with the gear 57, respectively.

By configuring the gear mechanism 51 as described above, when the motor M rotates forward and the pinion gear PG rotates right, the driving force is as follows: pinion gear PG (right rotation) → second one-way clutch 55 → It is transmitted in the order of shaft 34 (right rotation) → second connection gear CG2 (right rotation) → first connection gear CG1 (left rotation) → drive shaft 23 (left rotation). At this time, the driving force is transmitted to the gear 54 via the gear 56 (right rotation) and the gear 57 (left rotation), and the gear 54 and the shaft 53 rotate rightward. Since it is blocked by one one-way clutch 52, it is not transmitted to the drive shaft 23.

  When the motor M rotates in the reverse direction and the pinion gear PG rotates counterclockwise, the driving force is as follows: pinion gear PG (left rotation) → gear 56 (left rotation) → gear 57 (right rotation) → gear 54 (left rotation) ) → first one-way clutch 52 → drive shaft 23 (left rotation). At this time, since the driving force transmitted to the pinion gear PG is blocked by the second one-way clutch 55, it is not transmitted to the shaft 34 and the connection gear CG2 does not rotate. In the present embodiment, the state where the motor M is rotated in the reverse direction is referred to as a first state, and the state where the motor M is rotated in the forward direction is referred to as a second state.

  The ratio of the number of teeth of the first connection gear CG1 and the second connection gear CG2 is 1: 3, and the reduction ratio of the connection gear CG1 and the connection gear CG2 is 3. The ratio of the number of teeth of the gear 56 and the gear 57 is 2: 1, and the reduction ratio of the gear 56 and the gear 57 is 0.5. Furthermore, the ratio of the number of teeth of the gear 57 and the gear 54 is 1: 3, and the reduction ratio of the gear 54 and the gear 57 is 3. Therefore, in the second state, the total reduction ratio is 3, and in the first state, the total reduction ratio is 1.5 (= 0.5 × 3).

  With this configuration, when the pump unit 50 is driven in the first state as in the first and second embodiments, it is detected that the load torque of the pump unit 50 is large. In the second state, a large torque is transmitted to the drive shaft 23, and the drive gear G1 and the driven gear G2 are slowly rotated to peel off the ink fixing portion in the gear pump GP. Then, after peeling off the ink fixing portion, a small torque is transmitted to the drive shaft 23 in the first state, and the gear pump GP can be driven by rotating the drive gear G1 and the driven gear G2 quickly. That is, the pump unit 50 peels off the ink adhering portion in the gear pump GP, reduces the load on the driving gear G1 and the driven gear G2, and then rotates the driving gear G1 and the driven gear G2 quickly to reduce the suction force. Reduction can be reduced. As a result, in the pump unit 50, it is possible to prevent a reduction in the cleaning effect by the gear pump GP described above when starting from an unused state for a long period of time.

As mentioned above, according to this embodiment mentioned above, in addition to the effect of 1st Embodiment, there exist the following effects.
(4) In the present embodiment, the first and second one-way clutches 52 and 55 are provided so that the gear mechanism 51 can be switched between the first state and the second state. As a result, the number of parts can be reduced and the configuration can be simplified as compared with the pump unit 14 of the first embodiment, so that the printer 1 can be downsized.

In addition, embodiment of invention is not limited to said each embodiment, You may change as follows.
In the above embodiment, the gear mechanism 20 of the pump unit 14 is driven in the first state, and when it is detected that the load torque of the pump unit 14 is large, the gear mechanism 20 is driven in the second state. Instead, when the pump unit 14 is started, the pump unit 14 may be driven from the second state from the beginning and then driven in the first state. Accordingly, the ink fixing portion in the gear pump GP can be peeled off without detecting the load torque. Then, after peeling off the ink fixing portion, a small torque is transmitted to the drive shaft 23 in the first state, whereby the drive gear G1.
In addition, the gear pump GP can be driven by rapidly rotating the driven gear G2. As a result, the pump unit 14 can prevent a reduction in the cleaning effect by the gear pump GP described above. At this time, it is desirable to appropriately change the pump unit 14 and the printer 1. Similarly, the pump units 40 and 50 may be appropriately changed.

  In the above embodiment, the ratio of the number of teeth of the first connecting gear CG1 and the second connecting gear CG2 is 3: 1. However, the ratio is not limited to this, and a large driving force (torque) is applied to the driving gear G1 of the gear pump GP. This ratio of the number of teeth may be appropriately changed. Further, the gears constituting the pump units 14, 40, 50 may be appropriately changed in the same manner.

  In the above embodiment, the driving force (torque) is transmitted to the driving shaft 23 of the gear pump GP by setting the first state and the second state. However, the driving force (torque) is not limited to this, and the driven shaft 24 is not limited thereto. You may communicate directly to. At this time, it is desirable to appropriately change the configuration of the pump unit 14.

  In the above embodiment, the pump units 14, 40, 50 including the gear pump GP are configured to flow ink to the waste ink tank 16. However, the present invention is not limited to this. You may comprise so that it may supply.

  In the first embodiment, six colors of ink are supplied from the ink cartridge 10. However, the present invention is not limited to this. For example, seven colors of ink may be provided in the ink cartridge 10. At this time, it is desirable to appropriately change the configuration of the printer 1.

  In the above-described embodiment, the liquid ejecting apparatus is embodied in the printer 1. However, the present invention is not limited to this, and the liquid ejecting apparatus may be embodied in a liquid ejecting apparatus that ejects another liquid. For example, as a liquid ejecting apparatus for ejecting liquids such as electrode materials and color materials used in the manufacture of liquid crystal displays, EL displays, and surface-emitting displays, as a liquid ejecting apparatus for ejecting bioorganic materials used in biochip manufacturing, and as precision pipettes The sample injection device may be used.

FIG. 2 is a plan view for explaining the outline of the printer according to the embodiment. The perspective view for demonstrating the structure of the pump unit of 1st Embodiment. The top view for demonstrating the structure of the gear pump of the embodiment. The perspective view for demonstrating the structure of the gear pump of the embodiment. The top view for demonstrating the structure of the gear mechanism of the embodiment. The top view for demonstrating the structure of the gear mechanism of the embodiment. The top view for demonstrating operation | movement of the gear mechanism of the embodiment. The top view for demonstrating operation | movement of the gear mechanism of the embodiment. The perspective view for demonstrating the structure of the pump unit of 2nd Embodiment. The top view for demonstrating operation | movement of the gear mechanism of the embodiment. The top view for demonstrating operation | movement of the gear mechanism of the embodiment. The mechanism figure for demonstrating the structure of the pump unit of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer as liquid ejecting apparatus, 8 ... Recording head as liquid ejecting head, 14, 40, 50 ... Pump unit, 16 ... Waste ink tank constituting waste liquid storage mechanism, 20, 41, 51 ... First torque Gear mechanism as transmission mechanism and second torque transmission mechanism, 22... Pump chamber, 23... Driving shaft, 26... Ink suction port as inflow port, 25. And connecting members constituting the first engaging / disengaging member, 32, 33... Switching means and connecting member constituting the second engaging / disengaging member, 34... Supporting shaft, 42 .gear as the first rotating gear, 43. Gear as fourth rotating gear, 44 ... Planetary gear constituting switching means, 52 ... First one-way clutch constituting switching means, 55 ... Second constituting switching means 1-way clutch, CG1... First gear and first rotation gear and connection gear as second rotation gear, CG2... Second gear and second rotation gear and connection gear as third rotation gear, G1 ... drive gear, G2 ... driven gear, GP ... gear pump, HG1 ... helical gear as the first helical gear, HG2 ... helical gear as the second helical gear, M ... motor as the drive motor, PG ... pinion gear, S ... load torque detection means As a sensor, SG ... a sun gear constituting a switching means.

Claims (5)

A drive motor;
A gear pump that houses a drive gear and a driven gear that meshes with and is driven by the drive gear, sucks fluid from the inlet based on rotation of the drive gear, and flows the sucked fluid out from the outlet. When,
A pump unit comprising: a first torque transmission mechanism that rotates by applying a first driving torque to the driving gear based on a driving force of the driving motor;
A second torque transmission mechanism for applying and rotating a second driving torque larger than the first driving torque based on the driving force of the driving motor;
Switching means for selecting either the first torque transmission mechanism or the second torque transmission mechanism and transmitting the driving force of the drive motor to the drive gear via the selected torque transmission mechanism. A pump unit characterized by comprising. The pump unit according to claim 1, wherein
The first torque transmission mechanism includes a drive shaft connected to the drive gear, and a first helical gear that is rotatably supported by the drive shaft and rotates in mesh with a pinion gear connected to the drive motor,
The second torque transmission mechanism includes: a first gear fixed to the drive shaft of the drive gear; a support shaft; a second gear fixed to the support shaft and meshed with the first gear; A second helical gear that is rotatably supported by a support shaft and rotates in mesh with the pinion gear;
The switching means is provided on the drive shaft, and guides the first helical gear to two positions, a connection position for connecting to the drive shaft and a connection position for disconnecting the first helical gear based on the direction of rotation of the pinion gear. A first engagement / disengagement member that is provided on the support shaft, and a connection position for connecting the second helical gear to the connection shaft and a connection position for disconnecting the second helical gear based on the direction of rotation of the pinion gear. A pump unit comprising: a second engaging / disengaging member that guides to two positions. The pump unit according to claim 1, wherein
The first torque transmission mechanism includes a drive shaft connected to the drive gear and a first rotating gear fixed to the drive shaft,
The second torque transmission mechanism includes a second rotation gear fixed to the drive shaft of the drive gear, a support shaft, and a support shaft rotatably fixed to the support shaft or meshed with the second rotation gear. A third rotating gear and a fourth rotating gear fixed to the third rotating gear,
The switching means includes a sun gear coupled to the drive motor and a planetary gear meshing with the sun gear, and the planetary gear is selected from the first rotation gear and the fourth rotation gear based on the rotation direction of the sun gear. A pump unit configured to mesh with a heel. The pump unit according to claim 1, wherein
The first torque transmission mechanism is a drive shaft coupled to the drive gear;
The second torque transmission mechanism includes a first rotation gear fixed to the drive shaft, a support shaft, and a second rotation gear that is fixedly or rotatably supported by the support shaft and meshes with the first rotation gear. With rotating gear,
The switching means includes a first one-way clutch that transmits rotation based on rotation in one direction of the drive motor to the drive shaft, and a second that transmits rotation based on rotation in the other direction of the drive motor to the support shaft. A pump unit characterized by comprising a one-way clutch. A liquid ejecting apparatus comprising the pump unit according to any one of claims 1 to 4,
A liquid ejecting head for ejecting the liquid;
The pump unit for cleaning the liquid jet head;
A waste liquid storage mechanism for storing liquid discharged from the liquid ejecting head via the pump unit;
A load torque detecting means for detecting a load torque of the pump unit;
The switching means detects the load torque of the pump unit by the load torque detecting means, selects the second torque transmission mechanism when the load torque is large, and selects the second torque transmission mechanism when the load torque is small. A liquid ejecting apparatus comprising: a torque transmission mechanism selected to transmit a driving force of the driving motor to the driving gear.

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