This application claims the priority benefit of Japanese Patent Application No. 2021-079515, filed on May 10, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
The present disclosure relates to a tube pump and a printing apparatus.
Conventionally, a tube pump, with which a fluid is sent using a tube, has been used in various technical fields. For example, Japanese Unexamined Patent Publication No. 2020-172887 discloses a use of a tube pump (tube type pump device) in an inkjet printing apparatus that is a printing apparatus employing an inkjet method for performing printing. The tube pump includes, for example, a tube, a roller, and the like, and sends a fluid such as liquid by squeezing the tube with the roller. Furthermore, in this case, for example, the squeeze operation by the roller is repeated in a predetermined zone of the tube, with the roller caused to orbit around a predetermined center axis.
In the tube pump, a movement of the roller that has finished squeezing the tube, caused by the elasticity of the tube, may result in production of hitting sound (collision noise) that is unpleasant noise. More specifically, in the tube pump, a member in which a guide groove for holding a shaft of a roller is formed may be used as a roller holder which is a member for holding the roller. As the guide groove, a groove in which the shaft of the roller is movable within a certain range may be used. In this case, the roller holder holds the shaft of the roller at the position of one end of the guide groove, for example, at a tube squeezing timing. In this case, the roller may move in the guide groove toward the other end with a huge momentum, due to the elasticity of the tube, at a tube squeezing end timing. As a result, the roller may collide with the end of the guide groove, and the hitting sound thus produced by the collision may be accepted as unpleasant noise by a user.
In view of this, various configurations for preventing such production of hitting sound have been conventionally studied. For example, Japanese Unexamined Patent Publication No. 2020-172887 discloses a configuration using a guide member that comes into contact with a roller to regulate the movement of the roller. Nevertheless, there is still a demand for a new and more preferable configuration for preventing such production of hitting sound. All things considered, the present disclosure provides a tube pump and a printing apparatus.
An aspect of the disclosure provides a tube pump configured to send a fluid by using an elastic tube. The tube pump includes: the tube through which the fluid passes; a roller configured to move along a partial zone in a flow path in which the fluid is sent through the tube, while crushing the tube, to push out the fluid in the tube; and a roller holder configured to make the roller orbit around a predetermined center axis to make the roller repeatedly pass through a path along the partial zone, the roller holder being a member that makes the roller move while holding a shaft of the roller. In the roller holder, a guide groove is formed to have one end side and another end side, in a movement orientation in which the roller moves along the partial zone to push out the fluid, respectively defined as a rear side and a front side, the guide groove being a groove that receives the shaft of the roller to define a range in which the roller is movable with respect to the roller holder. The roller holder includes, as surfaces defining the guide groove: an inner side surface that is a surface guiding a movement of the shaft of the roller on a side closer to the center axis than the shaft of the roller; and an outer side surface that is a surface facing the inner side surface with the shaft of the roller interposed in between. While the roller moves along the partial zone, the shaft of the roller is held at a rear end position that is a position at an end on the rear side in the movement orientation in the guide groove. The inner side surface has a protrusion protruding toward the outer side surface.
The inventors of the present application have conducted intensive studies on a configuration with which production of hitting sound due to movement of a shaft of a roller in a guide groove of a roller holder can be appropriately prevented. As a result, the present inventors have found that the production of the hitting sound may be appropriately prevented by providing a protrusion on a surface, of surfaces defining the guide groove, on a side close to a center axis around which the roller orbits. Through further intensive studies, the present inventors have found the features required for achieving such an effect, and arrived at the present disclosure.
The present disclosure relates to a tube pump configured to send a fluid by using an elastic tube, the tube pump including: the tube through which the fluid passes; a roller configured to move along a partial zone in a flow path in which the fluid is sent through the tube, while crushing the tube, to push out the fluid in the tube; and a roller holder configured to make the roller orbit around a predetermined center axis to make the roller repeatedly pass through a path along the partial zone, the roller holder being a member that makes the roller move while holding a shaft of the roller, in which in the roller holder, a guide groove is formed to have one end side and another end side, in a movement orientation in which the roller moves along the partial zone to push out the fluid, respectively defined as a rear side and a front side, the guide groove being a groove that receives the shaft of the roller to define a range in which the roller is movable with respect to the roller holder, the roller holder includes, as surfaces defining the guide groove, an inner side surface that is a surface guiding a movement of the shaft of the roller on a side closer to the center axis than the shaft of the roller, and an outer side surface that is a surface facing the inner side surface with the shaft of the roller interposed in between, while the roller moves along the partial zone, the shaft of the roller is held at a rear end position that is a position at an end on the rear side in the movement orientation in the guide groove, and the inner side surface has a protrusion protruding toward the outer side surface.
With this configuration, due to the guide groove having the protrusion, for example, the roller that has dislodged from the rear end position of the guide groove can be appropriately prevented from colliding with the opposite end of the guide groove with a huge momentum. Thus, it is possible to appropriately prevent production of large hitting sound due to collision between the wall surface of the guide groove and the roller for example. With this configuration, the tube pump featuring excellent quietness can be appropriately provided for example.
In the present example, the tube is disposed to be at least partially curved in an arc shape, for example. The roller holder makes the roller orbit around the center axis, by rotating around the center axis determined based on a part of the tube having the arc shape, while the shaft of the roller is being held by the guide groove, for example. In this case, the partial zone is a zone including the arc-shaped part in the tube. With this configuration, for example, the tube can be appropriately squeezed by the roller, so that the fluid such as liquid in the tube can be appropriately sent.
The partial zone can be regarded as, for example, a squeeze zone in which the tube is squeezed by the roller, or the like. In this case, at the timing of passing through the partial zone, the roller is separated from the tube by being at a position other than the curved part in the tube. In this configuration, for example the roller is preferably held on the rear end position side of the guide groove, also while the roller is separated from the tube. More specifically, in this case, while the roller holder rotates in an orientation in which the fluid is pushed out, the roller holder holds the shaft of the roller between the rear end position of the guide groove and the protrusion, for example. With this configuration, for example, the roller that has dislodged from the rear end position of the guide groove can be more appropriately and surely prevented from colliding with the opposite end of the guide groove. The operation of thus holding the shaft of the roller can be regarded as, for example, holding the shaft of the roller on the one end side of the guide groove, regardless of whether the roller is contact with the tube, during forward rotation of the roller holder rotating in the orientation of pushing out the fluid.
In this configuration, during backward rotation of the roller holder rotating in an orientation opposite to that during the forward rotation, the roller holder may hold the shaft of the roller to be more on the other end side, which is opposite to the one end side on which the shaft of the roller is held during the forward rotation, than the protrusion in the guide groove. More specifically, during the backward rotation of the roller holder, the roller holder holds the shaft of the roller to be more on the other end side than the protrusion in the guide groove for example. With this configuration, for example, the roller holder can be appropriately rotated backward, while the roller is appropriately retracted. In this case, the protrusion may be inclined larger on the one end side than on the other end side, for example. With this configuration, for example, the roller can more appropriately move beyond the protrusion when the backward rotation is switched to the forward rotation, while being more surely prevented from moving beyond the protrusion during the forward rotation.
Immediately before the timing when the roller is separated from the tube, the roller is in contact with the tube at a position near the end of the arc-shaped part of the tube, for example. The part of the tube in contact with the roller should gradually expand from the crushed state as the roller moves. In this case the protrusion on the inner side surface of the guide groove comes into contact with the roller pushed by the tube gradually expanding, to prevent the roller from moving toward the other end side (front side) beyond the protrusion in the guide groove for example. With this configuration, for example, the shaft of the roller can be appropriately held between the rear end position in the guide groove and the protrusion. In this configuration, the outer side surface of the guide groove has a recess recessed in a direction away from the inner side surface, at a position of the inner side surface facing the protrusion for example. With this configuration, the width of the guide groove can be appropriately secured also at the position provided with the protrusion, for example.
The tube pump having the configuration described above may be used in a printing apparatus that performs printing based on an inkjet method for example. In this case, the printing apparatus includes an inkjet head configured to eject ink, an ink container configured to store the ink supplied to the inkjet head, and an ink supply path through which the ink is supplied from the ink container to the inkjet head by using the tube pump, for example. With this configuration, the printing apparatus featuring excellent quietness with production of hitting sound in the tube pump appropriately prevented can be appropriately provided, for example. The printing apparatus may include a maintenance unit configured to perform maintenance on the inkjet head and the like. In this case, the maintenance unit may perform an operation such as sucking ink from the inkjet head by using the tube pump for example.
The present disclosure can appropriately provide a tube pump featuring excellent quietness, for example.
Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings.
The plurality of inkjet heads 102 are ejection heads that eject ink onto the medium 50. In the present example, the plurality of inkjet heads 102 each include a plurality of nozzles, and eject ink of different colors. More specifically, in the illustrated configuration, the plurality of inkjet heads 102 eject ink of respective colors yellow (Y), magenta (M), cyan (C), and black (K). The platen 104 is a table-shaped member with which the medium 50 is held while facing the plurality of inkjet heads 102. The plurality of main tanks 106 are ink containers that store ink to be supplied to the plurality of inkjet heads 102. Furthermore, in the present example, the plurality of main tanks 106 store ink of different colors, and supply the ink to any one of the inkjet heads 102 through the ink supply path 108. As the main tank 106, for example, an ink bottle, an ink cartridge, or the like can be suitably used. The ink supply path 108 is an ink path, through which the ink is supplied from the plurality main tanks 106 to the plurality of inkjet heads 102. The carriage 110 is a holding member that holds the plurality of inkjet heads 102.
The scanning driving unit 112 is a driving unit that causes the plurality of inkjet heads 102 to perform a scanning operation of relatively moving with respect to the medium 50. In the present example, the scanning driving unit 112 causes the plurality of inkjet heads 102 to perform main scan and sub scan. In this case, the main scan can be regarded, for example, as an operation of ejecting ink while relatively moving, with respect to the medium 50, in a predetermined main scanning direction, or the like. The sub scan can be regarded, for example, as an operation of relatively moving with respect to the medium 50 in a sub scanning direction orthogonal to the main scanning direction, or the like. The maintenance unit 114 is configured to perform a maintenance operation on the plurality of inkjet heads 102. In the present example, the maintenance unit 114 performs maintenance on the inkjet head 102 by performing suction on the inkjet head 102 to suck out the ink in the inkjet head 102. The control unit 120 is, for example, a part of the printing apparatus 100 including a CPU and the like, and controls operations of parts of the printing apparatus 100, in accordance with a program (such as firmware for example) for controlling the operations of the printing apparatus 100. According to the present example, for example, the printing based on the inkjet method can be appropriately performed on the medium 50.
Furthermore, in the present example, the printing apparatus 100 is an example of a configuration using a tube pump, and executes the above-described operation using the tube pump in the ink supply path 108 and the maintenance unit 114.
As illustrated in the figure, the ink supply path 108 has a tube pump 200, for sending the ink, provided in the middle of the flow path through which the ink is supplied from the main tank 106 to the inkjet head 102. With this configuration, for example, the ink can be appropriately supplied to the inkjet head 102. The maintenance unit 114 includes a capping portion 152 and the tube pump 200. The capping portion 152 is a member that covers the nozzle surface of the inkjet head 102, when the maintenance is performed on the inkjet head 102. The tube pump 200 in the maintenance unit 114 sucks the ink from the nozzles of the inkjet head 102, by performing suction on a sealed space, including the nozzle surface of the inkjet head 102, formed by the covering using the capping portion 152. In this case, the tube pump 200 discharges the sucked ink to an ink collecting container or the like. With this configuration, for example, the maintenance can be appropriately performed on the inkjet head 102.
Next, features of the tube pump 200 used in the printing apparatus 100 of the present example will be described in more detail. For convenience of description, first of all, a tube pump 200 having a configuration different from that of the tube pump 200 used in the present example will be described.
In
The tube pump 200 is a pump for sending liquid such as ink, and includes a tube 202, a frame 204, a plurality of rollers 206, and the roller holder 208. In this case, the liquid sent by the tube pump 200 can be regarded as an example of the fluid. The tube 202 is a tube through which the liquid sent by the tube pump 200 passes. In the present example, the tube 202 is a flexible tube having elasticity, and is disposed to be at least partially curved in an arc shape. More specifically, in the case of the illustrated configuration, the tube 202 is disposed to be partially curved in an arc shape along a support surface formed in the frame 204. In this case, the tube 202 can also be regarded as being disposed in a U shape, as illustrated in the figure for example. The frame 204 is a housing that holds the tube 202 and the roller holder 208, and holds a part of the tube 202 along the support surface curved in an arc shape, and holds roller holder 208 in such a manner that the support surface and part of the roller holder 208 face each other with the tube 202 interposed therebetween. Thus, the frame 204 holds the tube 202 in such a manner that the tube 202 is sandwiched between the support surface and the roller holder 208.
The plurality of rollers 206 are rollers for squeezing the tube 202, and for example, as illustrated in
The roller holder 208 is a member that moves the roller 206 while holding the shaft of the roller 206, and makes the rollers 206 orbit around a predetermined center axis to make the rollers 206 repeatedly pass through a path along a partial zone of the tube 202. Making the roller 206 orbit around the center axis can be regarded as, for example, making the roller 206 move while making the shaft of the roller 206 orbit around an axis that is parallel to the shaft of the roller 206 and passes through a predetermined center position, or the like. The center axis is determined in accordance with, for example, the arc-shaped part of the tube 202. More specifically, in the present example, the center axis is an axis passing through the center of a circle corresponding to the arc-shaped part of the tube 202. The roller holder 208 is a wheel-shaped member that rotates around the center axis, and makes the plurality of rollers 206 orbit around the central axis, by rotating around the central axis while the shafts of the plurality of rollers 206 are being held in the plurality of respective guide grooves 300.
In the present example, the guide groove 300 in the roller holder 208 is a groove that penetrates the roller holder 208. The guide groove 300 can be regarded as, for example, a groove receiving the shaft of the roller 206 to define a range in which the roller 206 is movable with respect to the roller holder 208, or the like. The guide groove 300 can also be regarded as, for example, a configuration for guiding the movement of the roller 206 between a squeeze position and a retracted position that are described below, or the like. More specifically, in the case of the illustrated configuration, the guide groove 300 is a groove in which, during the forward rotation of the tube pump 200, the position on the rear end side is the squeeze position and the position on the front end side which is the other end is the retracted position. In this case, during the forward rotation of the tube pump 200 can be regarded as, for example, being in a state in which the roller holder 208 is rotated in an orientation for pushing out the liquid in the tube 202, or the like. During the forward rotation of the tube pump 200 can also be regarded as, for example, a state in which the rollers 206 are moved in an orientation for performing the liquid sending operation by the tube pump 200, or the like. In the case of the illustrated configuration, for example, the operation of rotating the roller holder 208 in the orientation of the arrow illustrated in
During the forward rotation, the roller 206 moving along a partial zone of the tube 202 is held at the squeeze position in the guide groove 300 of the roller holder 208, and thus moves while crushing the tube 202, as illustrated in
Furthermore, in the case of the illustrated configuration, a part other than the squeeze zone in the moving range of the roller 206 orbiting around the center axis, such as a zone indicated by a two-headed arrow in
As described above, the tube pump 200 of the present example has features that are the same as or similar to those of the tube pump 200 of the reference example, except for the shape of the guide groove 300 in the roller holder 208 and matters related to the shape. More specifically, as illustrated in the figure, the tube pump 200 of the present example includes the tube 202, the frame 204, the plurality of rollers 206, and the roller holder 208, as in the tube pump 200 of the reference example. The components in
As illustrated in
Furthermore, in the present example and in the reference example, the guide groove 300 can be regarded as, for example, a groove in which one end side is the rear side and the other end side is the front side in the orientation in which the roller 206 moves along the squeeze zone during the forward rotation. As illustrated in
As can be understood from the illustrated configuration and the like, the roller holder 208 further includes, as surfaces defining the guide groove 300, surfaces connecting the inner side surface 302 and the outer side surface 304, on one end side and the other end side of the guide groove 300 that are the squeeze position and the retracted position. In the present example and the reference example, the guide groove 300 is bent at the retracted position as illustrated in the figure. Therefore, the roller holder 208 has a surface for forming such a bent portion as the surface connecting the inner side surface 302 and the outer side surface 304 on the retracted position side. With such a configuration, the guide groove 300 holds the shaft of the roller 206 at the squeeze position while the roller 206 moves along the squeeze zone during the forward rotation.
As illustrated in
More specifically, a part of the inner side surface 302 of the guide groove 300 of the present example other than the protrusion 312 is curved to be closer to the center axis at a part farther from the squeeze position, for example. Considering the distance from the outer circumference of the roller holder 208, for example, the part of the inner side surface 302 other than the protrusion 312 can also be regarded as being curved to have a larger distance from the outer circumference of the roller holder 208 at a part farther from the squeeze position. In this case, the outer circumference of the roller holder 208 can be regarded as, for example, a position through which a part of the roller holder 208 farthest from the center axis passes as the roller holder 208 rotates, or the like.
On the other hand, in the present example, the protrusion 312 on the inner side surface 302 has a surface that is more separated from the center axis at a part farther from the squeeze position, to protrude toward the outer side surface 304. In this case, for example, as illustrated in the figure, at least part of the surface, of the surfaces defining the protrusion 312, on the side closer to the squeeze position can be regarded as the surface that is more separated from the center axis at a part farther from the squeeze position. The protrusion 312 can also be regarded, for example, as including a part that is closer to the outer circumference of the roller holder 208 at a part farther from the squeeze position. With such a configuration, for example, the protrusion 312 can be appropriately formed on the inner side surface 302 for example. In this case, the guide groove 300 in the tube pump 200 of the reference example can be regarded, for example, as being curved to be closer to the center axis at a part farther from squeeze position, over the entirety of the inner side surface 302.
In the present example, with the guide groove 300 being provided with the protrusion 312, during the forward rotation of the roller holder 208, the roller holder 208 holds the shaft of the roller 206 between the rear end position of the guide groove 300 and the protrusion 312. With this configuration, the roller 206 is held at the rear end position of the guide groove 300 by the roller holder 208, also while being separated from the tube 202 in the non-contact zone after passing through the squeeze zone. With this configuration, the roller 206 can be appropriately prevented from moving to the retracted position in the guide groove 300 during the forward rotation, for example. Thus, even when the roller 206 receives, from the tube 202, force in a direction away from the squeeze position in the guide groove 300, it is possible to appropriately and surely prevent the roller 206 from dislodging from the squeeze position and colliding with the opposite end of the guide groove with a huge momentum, for example. Thus, it is possible to appropriately prevent production of large hitting sound due to collision between the wall surface of the guide groove 300 and the roller 206 for example. All things considered, according to the present example, the tube pump 200 featuring excellent quietness can be appropriately provided for example. Furthermore, with such a tube pump 200 used in the printing apparatus 100 (see
Here, in the present example, the operation of holding the shaft of the roller 206 by means of the guide groove 300 during the forward rotation can be regarded as, for example, an operation of holding the shaft of the roller 206 on one end side of the guide groove 300 regardless of whether the roller 206 is in contact with the tube 202. Furthermore, as can be understood from the matters described above and the like, the protrusion 312 may be formed to prevent the shaft of the roller 206 from moving beyond the protrusion 312, toward the retracted position side during the forward rotation, without compromising the function of the guide groove 300 for example. More generally, the protrusion 312 can also be regarded, for example, as functioning to attenuate the momentum of the roller 206 dislodging from the squeeze position. In this case, the attenuation of the momentum of the roller 206 can be regarded, for example, as reducing the momentum of the roller 206 from that in the case where the guide groove 300 not having the protrusion 312 formed is used, or the like. The use of the guide groove 300 not having the protrusion 312 formed can be regarded, for example, as a use of a guide groove 300 corresponding to a configuration obtained by removing the protrusion 312 from the guide groove 300 in the tube pump 200 of the present example, or the like. The guide groove 300 corresponding to a configuration obtained by removing the protrusion 312 can be regarded, for example, as being the same as or similar to the guide groove 300 in the tube pump 200 of the reference example, or the like. The guide groove 300 corresponding to a configuration obtained by removing the protrusion 312 can be regarded as, for example, using the inner side surface 302 smoothly curved due to the absence of the protrusion 312 as illustrated in a broken line in the right diagram in
Furthermore, in the present example, the protrusion 312 is formed between the squeeze position and the retracted position in the guide groove 300 and in the vicinity of the squeeze position, for example, as illustrated in the figure. In this case, for example, the protrusion 312 may be formed to come into contact with the roller 206 at a timing when the roller 206 that has passed through the squeeze zone is separated from the tube 202. The protrusion 312 coming into contact with the roller 206 can be regarded as, for example, the protrusion 312 coming into contact with the shaft of the roller 206, or the like. The timing at which the roller 206 that has passed through the squeeze zone is separated from the tube 202 can be regarded as, for example, a timing at which the roller 206 moves into the non-contact zone from the squeeze zone due to the rotation of the roller holder 208, or the like. The timing at which the roller 206 moves into the non-contact zone from the squeeze zone can be regarded as, for example, a timing including immediately before the roller 206 is separated from the tube 202, or the like. In the case of the tube pump 200 of the present example, immediately before the timing when the roller 206 is separated from the tube 202, the roller 206 is in contact with the tube 202 at a position near the end of the arc-shaped part of the tube 202. In this case, at the timing of passing through the squeeze zone, the roller 206 is separated from the tube 202 by being at a position other than the curved part in the tube 202. It is conceivable that the part of the tube 202 in contact with the roller 206 gradually expand from the crushed state as the roller 206 moves. In this case, the gradual expansion of the tube 202 immediately before the timing when the roller 206 is separated from the tube 202 can be regarded as, for example, gradual reduction in the level of crushing of the tube 202 at the position in contact with the roller 206 from that in a state where the level of crushing of the tube 202 is the highest in the squeeze zone, as a result of the movement of the roller 206, or the like.
Furthermore, in this case, the protrusion 312 on the inner side surface 302 of the guide groove 300 can be regarded as, for example, coming into contact with the roller 206 pushed away from the squeeze position by the gradually expanding tube 202 while the tube 202 and the roller 206 are in contact with each other, or the like. By being in contact with the roller 206 receiving the elastic force from the gradually expanding tube 202, for example, the protrusion 312 prevents the movement of the shaft of the roller 206 toward the retracted position side beyond the protrusion 312, that is, toward the front side beyond the protrusion 312 in the guide groove 300 during the forward rotation or the tube pump 200, at the timing when the roller 206 is separated from the tube 202. Thus, at the timing when the roller 206 passes through the squeeze zone due to the rotation of the roller holder 208 during the forward rotation, the protrusion 312 prevents the roller 206, receiving the force in the direction away from the squeeze position from the tube 202, from moving beyond the protrusion 312. With this configuration, for example, the shaft of the roller 206 can be appropriately held between the squeeze position and the protrusion 312 in the guide groove 300, during the forward rotation of the tube pump 200. Therefore, according to the present example, for example, the roller 206 can be prevented from colliding with the wall surface of the guide groove 300 at the retracted position. Thus, it is possible to more appropriately prevent production of large hitting sound due to collision between the wall surface of the guide groove 300 and the roller 206 for example.
In this case, for example, the protrusion 312 can also be regarded as regulating the movement of the roller 206 at the timing when the roller 206 is separated from the tube 202 for example. Furthermore, for example, the protrusion 312 can also be regarded as pressing the roller 206, until the expanded state of the tube 202 is achieved for example.
In the tube pump 200, a backward rotation operation of rotating the roller holder 208 in an orientation opposite to that during the forward rotation may be performed. In the case of the tube pump 200 of the present example, during the backward rotation, the roller holder 208 holds the shaft of the roller 206 to be more on the retracted position side than the protrusion 312 in the guide groove 300. In this case, the retracted position side in the guide groove 300 can be regarded as, for example, the other end side opposite to the one end side where the shaft of the roller 206 is held during the forward rotation, or the like. With this configuration, for example, the roller holder 208 can be appropriately rotated backward, with the roller 206 appropriately retracted to a position to be not in contact with the tube 202 for example.
Although not illustrated in
Next, supplementary description as well as description on modifications, and the like of the configuration described above will be given. As can be understood from the above description and the like, the shape of the protrusion 312 of the guide groove 300 is not limited to the shape specifically illustrated in
In this regard, for the sake of prevention of the movement the roller 206 beyond the protrusion 312, the protrusion 312 can be regarded as preferably being formed to have a large size or a high protruding height. However, with such a configuration, backflow of liquid is likely to occur during the backward rotation. More specifically, as described above, during the backward rotation, for example, the rotation of the roller holder 208 causes the roller 206 to move from the squeeze position to the retracted position. However, the protrusion 312 having a large size or the like makes the movement of the roller 206 from the squeeze position to the retracted position difficult, and this may result in a higher possibility of occurrence of backflow of a slight amount of liquid.
Thus, the shape of the protrusion 312 is preferably determined while further taking the appropriate prevention of the backflow into consideration. In this case, the position and the shape of the protrusion 312 may be determined in such a manner that the amount of backflow occurring falls within a tolerable range set in advance, for example. More specifically, for example, the height of the protrusion 312 may be set to a height with which the movement of the roller 206 from the squeeze position to the retracted position during the backward rotation is not hindered. In this case, the movement of the roller 206 is not hindered can be regarded as, for example, the problem of backflow of liquid not occurring due to the influence of the protrusion 312, or the like. Furthermore, for preventing the backflow of liquid during the backward rotation, for example, a width of the guide groove 300 at the position of the protrusion 312 may be set to be wider than that in other parts, or the other like configuration may be employed. In this case, for example, the guide groove 300 may have a large width at the position of the protrusion 312. with the recess 314 having a recessed amount overwhelming the protruding height of the protrusion 312.
As can be understood from the above description and the like, the tube 202 may be used while switching between the forward rotation operation and the backward rotation operation as appropriate. The roller 206 moves beyond the protrusion 312 in the guide groove 300, at each of a timing of switching from the forward rotation to the backward rotation and a timing of switching from the backward rotation to the forward rotation. Thus, preferable shapes of the guide groove 300 and the protrusion 312 can be regarded to be, for example, shapes for holding the roller 206 on the rear end side in the rotation direction of the roller holder 208 during each of the forward rotation and the backward rotation, and enabling the roller 206 to move over the protrusion 312 when the rotation direction of the roller holder 208 is changed. With this configuration, the forward rotation operation and the backward rotation operation of the tube pump 200 can be appropriately performed.
Furthermore, in the present example, the roller 206 at the retracted position during the backward rotation is maintained in a state of receiving no elastic force from the tube 202, by not being in contact with the tube 202. In this case, the prevention of the movement of the roller 206 using the protrusion 312 can be regarded to be, for example, particularly important during the forward rotation of the tube pump 200. Thus, the protrusion 312 may be formed to have a shape with the inclination on the squeeze position side (one end side) being larger than the inclination on the retracted position side (other end side) for example. In this case, the shape with the inclination on the squeeze position side being larger than the inclination on the retracted position side can be regarded as, for example, a shape with the maximum inclination on the squeeze position side being larger than the maximum inclination on the retracted position side, or the like. With this configuration, for example, the roller 206 can more appropriately move beyond the protrusion 312 when the backward rotation is switched to the forward rotation, while more surely preventing the roller 206 from moving over the protrusion 312 during the forward rotation.
As can be understood from the configuration illustrated in
In the above description, the configuration in which the recess 314 is formed in accordance with the shape of the protrusion 312 is mainly illustrated and described. On the other hand, the shape of the recess 314 may have a shape that is not the same as that of the protrusion 312. In this case, the shape of the recess 314 being the same as that of the protrusion 312 can be regarded as, for example, the surfaces defining the protruding shape of the protrusion 312 being the same as the surfaces defining the recessed shape of the recess 314, or the like. More specifically, for example, as illustrated in
Furthermore, in the above description, the configuration in which the protrusion 312 is formed at a position slightly separated from the rear end of the guide groove 300 during the forward rotation is mainly illustrated and described. In this case, the protrusion 312 may be positioned to enable the shaft of the roller 206 to be held between the protrusion 312 and the rear end position of the guide groove 300. More specifically, the protrusion 312 may be positioned to make a distance between the protrusion 312 and the rear end position of the guide groove 300 not smaller than the width of the shaft of the roller 206. With this configuration, for example, the protrusion 312 can be appropriately prevented from affecting the roller 206 held at the squeeze position. Furthermore, in this case, the distance between the protrusion 312 and the rear end position of the guide groove 300 can be regarded as, for example, a distance between the rear end position of the guide groove 300 and a part of the inner side surface 302 that is raised relative to other parts due to the presence of the protrusion 312, or the like. Furthermore, this distance can also be regarded as, for example, a distance between a position of the hem of the protrusion 312 where raising in a direction away from the center axis of the roller holder 208 starts and the rear end position of the guide groove 300, or the like.
On the other hand, in a modification of the configuration of the guide groove 300, for example, as illustrated in
Considering such a feature of the protrusion 312, the protrusion 312 can also be regarded, for example, as being formed in the guide groove 300 illustrated in
As described above, for example, the guide groove 300 with the configuration illustrated in
Furthermore, in the above description, the configuration in which the protrusion 312 is formed at a position close the rear end of the guide groove 300 during the forward rotation is mainly illustrated and described. On the other hand, for the sake of attenuation of the momentum of the roller 206 before reaching the retracted position, the protrusion 312 may be formed at a position closer to the retracted position as illustrated in
When the protrusion 312 is formed as illustrated in
To attenuate the momentum of the roller 206 before reaching the retracted position, also in a case where the protrusion 312 is formed at a position closer to the rear end of the guide groove 300 during the forward rotation in a further modification of the guide groove 300, the protrusion 312 may be formed to have a shape with which the roller 206 moves beyond the protrusion 312 at a timing when the roller 206 enters the non-contact zone after passing through the squeeze zone, or the like. Also in this case, by attenuating the momentum of the movement of the roller 206 with the protrusion 312, the production of large hitting sound can be appropriately prevented, compared with a case where the protrusion 312 is not formed, for example.
In the above description, the configuration in the case of ejecting the ink on the medium is mainly described for the printing apparatus 100 (see
The present disclosure can be suitably used for, for example, a tube pump.
Number | Date | Country | Kind |
---|---|---|---|
2021-079515 | May 2021 | JP | national |