TUBE PUMP AND PRINTING APPARATUS

A tube pump that sends a fluid includes a tube, a roller, and a roller holder. In the roller holder, a guide groove is formed that receives a shaft of the roller and defines a range in which the roller is movable with respect to the roller holder. The roller holder has an inner side surface and an outer side surface as surfaces defining the guide groove in the roller holder. The inner side surface has a protrusion protruding toward the outer side surface.

CROSS REFERENCE TO RELATED APPLICATIONS

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.

TECHNICAL FIELD

The present disclosure relates to a tube pump and a printing apparatus.

DESCRIPTION OF THE BACKGROUND ART

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.

SUMMARY

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.

DETAILED DESCRIPTION OF EMBODIMENTS

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.FIGS. 1A, 1B, and 1Care diagrams illustrating a printing apparatus100according to an embodiment of the present disclosure, andFIG. 1Aillustrates an example of a configuration of a main part of the printing apparatus100. In the present example, the printing apparatus100is an inkjet printer that performs printing based on an inkjet method on a printing target medium (medium)50, and includes a plurality of inkjet heads102, a platen104, a plurality of main tanks106, an ink supply path108, a carriage110, a scanning driving unit112, a maintenance unit114, and a control unit120. The printing apparatus100may have features that are the same as or similar to those of known inkjet printers, except for the points described below. For example, in addition to the configuration illustrated inFIGS. 1A, 1B, and 1C, the printing apparatus100may further include a configuration that is the same as or similar to those of known inkjet printers.

The plurality of inkjet heads102are ejection heads that eject ink onto the medium50. In the present example, the plurality of inkjet heads102each include a plurality of nozzles, and eject ink of different colors. More specifically, in the illustrated configuration, the plurality of inkjet heads102eject ink of respective colors yellow (Y), magenta (M), cyan (C), and black (K). The platen104is a table-shaped member with which the medium50is held while facing the plurality of inkjet heads102. The plurality of main tanks106are ink containers that store ink to be supplied to the plurality of inkjet heads102. Furthermore, in the present example, the plurality of main tanks106store ink of different colors, and supply the ink to any one of the inkjet heads102through the ink supply path108. As the main tank106, for example, an ink bottle, an ink cartridge, or the like can be suitably used. The ink supply path108is an ink path, through which the ink is supplied from the plurality main tanks106to the plurality of inkjet heads102. The carriage110is a holding member that holds the plurality of inkjet heads102.

The scanning driving unit112is a driving unit that causes the plurality of inkjet heads102to perform a scanning operation of relatively moving with respect to the medium50. In the present example, the scanning driving unit112causes the plurality of inkjet heads102to 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 medium50, 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 medium50in a sub scanning direction orthogonal to the main scanning direction, or the like. The maintenance unit114is configured to perform a maintenance operation on the plurality of inkjet heads102. In the present example, the maintenance unit114performs maintenance on the inkjet head102by performing suction on the inkjet head102to suck out the ink in the inkjet head102. The control unit120is, for example, a part of the printing apparatus100including a CPU and the like, and controls operations of parts of the printing apparatus100, in accordance with a program (such as firmware for example) for controlling the operations of the printing apparatus100. According to the present example, for example, the printing based on the inkjet method can be appropriately performed on the medium50.

Furthermore, in the present example, the printing apparatus100is an example of a configuration using a tube pump, and executes the above-described operation using the tube pump in the ink supply path108and the maintenance unit114.FIG. 1Bis a diagram illustrating one example of a configuration of the ink supply path108, and illustrates one example of a path for supplying ink from one main tank106corresponding to one color ink to the inkjet head102in a simplified manner.FIG. 1Cis a diagram illustrating one example of a configuration of the maintenance unit114, and illustrates one example of a configuration for performing suction on one inkjet head102corresponding to one color ink in a simplified manner. In the present example, the ink supply path108has the configuration illustrated inFIG. 1Bfor each ink color. The maintenance unit114has a configuration illustrated inFIG. 1Cfor each ink color.

As illustrated in the figure, the ink supply path108has a tube pump200, for sending the ink, provided in the middle of the flow path through which the ink is supplied from the main tank106to the inkjet head102. With this configuration, for example, the ink can be appropriately supplied to the inkjet head102. The maintenance unit114includes a capping portion152and the tube pump200. The capping portion152is a member that covers the nozzle surface of the inkjet head102, when the maintenance is performed on the inkjet head102. The tube pump200in the maintenance unit114sucks the ink from the nozzles of the inkjet head102, by performing suction on a sealed space, including the nozzle surface of the inkjet head102, formed by the covering using the capping portion152. In this case, the tube pump200discharges 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 head102.

Next, features of the tube pump200used in the printing apparatus100of the present example will be described in more detail. For convenience of description, first of all, a tube pump200having a configuration different from that of the tube pump200used in the present example will be described.FIGS. 2A and 2Bare diagrams illustrating general features of the tube pump200, and illustrate an example of a configuration of the tube pump200(hereinafter, referred to as a tube pump200of the reference example) having a configuration different from that of the tube pump200used in the present example.FIGS. 2A and 2Billustrate examples of states of the tube pump200of the reference example at different timings during the forward rotation of the tube pump200.

InFIGS. 2A and 2B, for convenience of illustration, the configuration of a main part of the tube pump200is illustrated while being appropriately simplified. The tube pump200of the reference example illustrated inFIGS. 2A and 2Bcan be regarded as a tube pump200as a result of omitting the feature parts of the tube pump200used in the printing apparatus100of the present example, or the like, for example. More specifically, as will be described in more detail later, the tube pump200used in the present example has features that are the same as or similar to those of the tube pump200of the reference example, except for the shape of a guide groove300in a roller holder208and matters related to the shape. Therefore, in the following description, common reference numerals are used for the present example and the reference example, and the description on the features of the tube pump200of the reference example is given also as a description on the features of the tube pump200of the present example. The difference between the tube pump200of the present example and the tube pump200of the reference example will be described in more detail later.

The tube pump200is a pump for sending liquid such as ink, and includes a tube202, a frame204, a plurality of rollers206, and the roller holder208. In this case, the liquid sent by the tube pump200can be regarded as an example of the fluid. The tube202is a tube through which the liquid sent by the tube pump200passes. In the present example, the tube202is 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 tube202is disposed to be partially curved in an arc shape along a support surface formed in the frame204. In this case, the tube202can also be regarded as being disposed in a U shape, as illustrated in the figure for example. The frame204is a housing that holds the tube202and the roller holder208, and holds a part of the tube202along the support surface curved in an arc shape, and holds roller holder208in such a manner that the support surface and part of the roller holder208face each other with the tube202interposed therebetween. Thus, the frame204holds the tube202in such a manner that the tube202is sandwiched between the support surface and the roller holder208.

The plurality of rollers206are rollers for squeezing the tube202, and for example, as illustrated inFIG. 2A, move along a partial zone of the flow path in which the liquid is sent through the tube202, while crushing the tube202, to push out the liquid inside the tube202. In this case, the operation of the roller206can be regarded as, for example, an operation of squeezing the tube202in one direction along the tube202disposed in a U shape, or the like. The roller206has a shaft that is parallel to a direction orthogonal to a direction in which the roller moves while squeezing the tube202, and is supported by the roller holder208with this shaft inserted in the guide groove300of the roller holder208.

The roller holder208is a member that moves the roller206while holding the shaft of the roller206, and makes the rollers206orbit around a predetermined center axis to make the rollers206repeatedly pass through a path along a partial zone of the tube202. Making the roller206orbit around the center axis can be regarded as, for example, making the roller206move while making the shaft of the roller206orbit around an axis that is parallel to the shaft of the roller206and 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 tube202. 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 tube202. The roller holder208is a wheel-shaped member that rotates around the center axis, and makes the plurality of rollers206orbit around the central axis, by rotating around the central axis while the shafts of the plurality of rollers206are being held in the plurality of respective guide grooves300.

In the present example, the guide groove300in the roller holder208is a groove that penetrates the roller holder208. The guide groove300can be regarded as, for example, a groove receiving the shaft of the roller206to define a range in which the roller206is movable with respect to the roller holder208, or the like. The guide groove300can also be regarded as, for example, a configuration for guiding the movement of the roller206between 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 groove300is a groove in which, during the forward rotation of the tube pump200, 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 pump200can be regarded as, for example, being in a state in which the roller holder208is rotated in an orientation for pushing out the liquid in the tube202, or the like. During the forward rotation of the tube pump200can also be regarded as, for example, a state in which the rollers206are moved in an orientation for performing the liquid sending operation by the tube pump200, or the like. In the case of the illustrated configuration, for example, the operation of rotating the roller holder208in the orientation of the arrow illustrated inFIG. 2Acan be regarded as the operation during the forward rotation. The squeeze position can be regarded as, for example, the position of the roller206for performing the operation of squeezing the tube202, or the like. Furthermore, in the case of the present example, the position in the guide groove300on the rear end side during the forward rotation is the squeeze position. Therefore, the squeeze position can also be regarded as, for example, an end position in the guide groove300on the rear side in the movement orientation (rear end position), or the like. The retracted position can be regarded as a position where the roller206separated from the tube202is retracted, or the like. In the present example, the retracted position is an end position (front end position) of the guide groove300on the side opposite to the squeeze position.

During the forward rotation, the roller206moving along a partial zone of the tube202is held at the squeeze position in the guide groove300of the roller holder208, and thus moves while crushing the tube202, as illustrated inFIG. 2Afor example. In this case, the zone in which the roller206moves while crushing the tube202can be regarded as, for example, a squeeze zone in the moving range of the roller206orbiting around the center axis. Furthermore, in the present example, the squeeze zone is a zone including the arc-shaped part in the tube202. According to the present example, for example, the tube202can be appropriately squeezed by the roller206, so that the liquid in the tube202can be appropriately sent.

Furthermore, in the case of the illustrated configuration, a part other than the squeeze zone in the moving range of the roller206orbiting around the center axis, such as a zone indicated by a two-headed arrow inFIG. 2Bfor example, is a non-contact zone in which the roller206and the tube202do not come into contact with each other. In this case, for example, as illustrated inFIG. 2B, at the timing when the roller206moves into the non-contact zone after passing through the squeeze zone, the roller206is bounced up by the elastic force (resilience force) of the tube202, and moves toward the retracted position on the other end side of the guide groove300. Such a movement operation of the roller206can be regarded, for example, as an operation of moving in a direction away from the squeeze position in accordance with the elastic force of the tube202, or the like. In this case, with the tube pump200of the reference example, a large hitting sound might be produced due to collision between the rollers206and a wall surface of the guide groove300. On the other hand, in the tube pump200of the present example, the guide groove300has a shape different from that in the tube pump200of the reference example, for appropriately preventing the production of the large hitting sound. In view of this, the features of the tube pump200of the present example will be described in detail below.

FIGS. 3A and 3Bare diagrams illustrating the features of the tube pump200of the present example in detail. Specifically,FIG. 3Aillustrates an example of a configuration of the tube pump200of the present example.FIG. 3Bis a diagram illustrating shapes of the guide grooves300of the reference example and the present example for comparison. InFIG. 3B, the left drawing illustrates the shape of the guide groove300in the roller holder208in the tube pump200of the reference example. The right drawing illustrates the shape of the guide groove300in the roller holder208in the tube pump200of the present example.

As described above, the tube pump200of the present example has features that are the same as or similar to those of the tube pump200of the reference example, except for the shape of the guide groove300in the roller holder208and matters related to the shape. More specifically, as illustrated in the figure, the tube pump200of the present example includes the tube202, the frame204, the plurality of rollers206, and the roller holder208, as in the tube pump200of the reference example. The components inFIGS. 3A and 3Bdenoted with reference numerals that are the same as those inFIGS. 2A and 2Bmay have features that are the same as or similar to those of the components inFIGS. 2A and 2B, except for the points described below. The tube pump200may have features that are the same as or similar to those of known tube pumps, except for the points described below.

As illustrated inFIG. 3A, also in the tube pump200of the present example, the roller206, in the squeeze zone during the forward rotation, is held at the squeeze position in the guide groove300to move while crushing the tube202. Still, the shape of the guide groove300in the present example is different from that in the tube pump200of the reference example, resulting in a movement of the roller206at the timing of entering the non-contact zone after passing through the squeeze zone differing from that of the roller206of the reference example. The movement of the roller206of the present example will be described in more detail later.

Furthermore, in the present example and in the reference example, the guide groove300can 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 roller206moves along the squeeze zone during the forward rotation. As illustrated inFIG. 3B, the roller holder208has an inner side surface302and an outer side surface304as surfaces defining the guide groove300. In this case, the inner side surface302can be regarded as, for example, a surface defining a side surface of the guide groove300, on the inner side of the roller holder208, or the like. The inner side of the roller holder208can be regarded as, for example, a side farther from the tube202regarding the positional relationship with respect to the tube202in the squeeze zone, or the like. The inner side surface302can also be regarded as, for example, a surface that guides the movement of the roller206on a side closer to the rotation center axis of the roller holder208than the shaft of the roller206, or the like. The outer side surface304can be regarded as, for example, a surface defining a side surface of the guide groove300at a position more on the outer side of the roller holder208than the inner side surface302, or the like. The outer side of the roller holder208can also be regarded as, for example, a side closer the tube202regarding the relationship with the tube202in the squeeze zone, or the like. The outer side surface304can also be regarded as, for example, a surface facing the inner side surface302with the shaft of the roller206interposed therebetween, or the like.

As can be understood from the illustrated configuration and the like, the roller holder208further includes, as surfaces defining the guide groove300, surfaces connecting the inner side surface302and the outer side surface304, on one end side and the other end side of the guide groove300that are the squeeze position and the retracted position. In the present example and the reference example, the guide groove300is bent at the retracted position as illustrated in the figure. Therefore, the roller holder208has a surface for forming such a bent portion as the surface connecting the inner side surface302and the outer side surface304on the retracted position side. With such a configuration, the guide groove300holds the shaft of the roller206at the squeeze position while the roller206moves along the squeeze zone during the forward rotation.

As illustrated inFIG. 3Bfor comparison, the guide groove300in the roller holder208of the tube pump200of the present example and the guide groove300in the roller holder208of the tube pump200of the reference example are different from each other by being provided with and not provided with a protrusion312for example. More specifically, in the present example, the inner side surface302of the guide groove300has the protrusion312protruding toward the outer side surface304. The protrusion312can be regarded as, for example, a bump formed in the guide groove300, or the like. In the tube pump200of the present example, the outer side surface304of the guide groove300has, at a position facing the protrusion312on the inner side surface302, a recess314recessed in a direction away from the inner side surface302, to correspond to the protrusion312provided to the inner side surface302. In this case, the recess314is recessed to make the guide groove300have a width, at the position of the protrusion312, not smaller than the width of the roller206. With this configuration, for example, the roller206can be appropriately prevented from failing to pass through the position of the protrusion312in the guide groove300. Furthermore, with this configuration, the width of the guide groove300can be appropriately secured also at the position provided with the protrusion312, for example.

More specifically, a part of the inner side surface302of the guide groove300of the present example other than the protrusion312is 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 holder208, for example, the part of the inner side surface302other than the protrusion312can also be regarded as being curved to have a larger distance from the outer circumference of the roller holder208at a part farther from the squeeze position. In this case, the outer circumference of the roller holder208can be regarded as, for example, a position through which a part of the roller holder208farthest from the center axis passes as the roller holder208rotates, or the like.

On the other hand, in the present example, the protrusion312on the inner side surface302has a surface that is more separated from the center axis at a part farther from the squeeze position, to protrude toward the outer side surface304. In this case, for example, as illustrated in the figure, at least part of the surface, of the surfaces defining the protrusion312, 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 protrusion312can also be regarded, for example, as including a part that is closer to the outer circumference of the roller holder208at a part farther from the squeeze position. With such a configuration, for example, the protrusion312can be appropriately formed on the inner side surface302for example. In this case, the guide groove300in the tube pump200of 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 surface302.

In the present example, with the guide groove300being provided with the protrusion312, during the forward rotation of the roller holder208, the roller holder208holds the shaft of the roller206between the rear end position of the guide groove300and the protrusion312. With this configuration, the roller206is held at the rear end position of the guide groove300by the roller holder208, also while being separated from the tube202in the non-contact zone after passing through the squeeze zone. With this configuration, the roller206can be appropriately prevented from moving to the retracted position in the guide groove300during the forward rotation, for example. Thus, even when the roller206receives, from the tube202, force in a direction away from the squeeze position in the guide groove300, it is possible to appropriately and surely prevent the roller206from 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 groove300and the roller206for example. All things considered, according to the present example, the tube pump200featuring excellent quietness can be appropriately provided for example. Furthermore, with such a tube pump200used in the printing apparatus100(seeFIG. 1), the printing apparatus100featuring excellent quietness can be appropriately provided for example.

Here, in the present example, the operation of holding the shaft of the roller206by means of the guide groove300during the forward rotation can be regarded as, for example, an operation of holding the shaft of the roller206on one end side of the guide groove300regardless of whether the roller206is in contact with the tube202. Furthermore, as can be understood from the matters described above and the like, the protrusion312may be formed to prevent the shaft of the roller206from moving beyond the protrusion312, toward the retracted position side during the forward rotation, without compromising the function of the guide groove300for example. More generally, the protrusion312can also be regarded, for example, as functioning to attenuate the momentum of the roller206dislodging from the squeeze position. In this case, the attenuation of the momentum of the roller206can be regarded, for example, as reducing the momentum of the roller206from that in the case where the guide groove300not having the protrusion312formed is used, or the like. The use of the guide groove300not having the protrusion312formed can be regarded, for example, as a use of a guide groove300corresponding to a configuration obtained by removing the protrusion312from the guide groove300in the tube pump200of the present example, or the like. The guide groove300corresponding to a configuration obtained by removing the protrusion312can be regarded, for example, as being the same as or similar to the guide groove300in the tube pump200of the reference example, or the like. The guide groove300corresponding to a configuration obtained by removing the protrusion312can be regarded as, for example, using the inner side surface302smoothly curved due to the absence of the protrusion312as illustrated in a broken line in the right diagram inFIG. 3B, or the like.

Furthermore, in the present example, the protrusion312is formed between the squeeze position and the retracted position in the guide groove300and in the vicinity of the squeeze position, for example, as illustrated in the figure. In this case, for example, the protrusion312may be formed to come into contact with the roller206at a timing when the roller206that has passed through the squeeze zone is separated from the tube202. The protrusion312coming into contact with the roller206can be regarded as, for example, the protrusion312coming into contact with the shaft of the roller206, or the like. The timing at which the roller206that has passed through the squeeze zone is separated from the tube202can be regarded as, for example, a timing at which the roller206moves into the non-contact zone from the squeeze zone due to the rotation of the roller holder208, or the like. The timing at which the roller206moves into the non-contact zone from the squeeze zone can be regarded as, for example, a timing including immediately before the roller206is separated from the tube202, or the like. In the case of the tube pump200of the present example, immediately before the timing when the roller206is separated from the tube202, the roller206is in contact with the tube202at a position near the end of the arc-shaped part of the tube202. In this case, at the timing of passing through the squeeze zone, the roller206is separated from the tube202by being at a position other than the curved part in the tube202. It is conceivable that the part of the tube202in contact with the roller206gradually expand from the crushed state as the roller206moves. In this case, the gradual expansion of the tube202immediately before the timing when the roller206is separated from the tube202can be regarded as, for example, gradual reduction in the level of crushing of the tube202at the position in contact with the roller206from that in a state where the level of crushing of the tube202is the highest in the squeeze zone, as a result of the movement of the roller206, or the like.

Furthermore, in this case, the protrusion312on the inner side surface302of the guide groove300can be regarded as, for example, coming into contact with the roller206pushed away from the squeeze position by the gradually expanding tube202while the tube202and the roller206are in contact with each other, or the like. By being in contact with the roller206receiving the elastic force from the gradually expanding tube202, for example, the protrusion312prevents the movement of the shaft of the roller206toward the retracted position side beyond the protrusion312, that is, toward the front side beyond the protrusion312in the guide groove300during the forward rotation or the tube pump200, at the timing when the roller206is separated from the tube202. Thus, at the timing when the roller206passes through the squeeze zone due to the rotation of the roller holder208during the forward rotation, the protrusion312prevents the roller206, receiving the force in the direction away from the squeeze position from the tube202, from moving beyond the protrusion312. With this configuration, for example, the shaft of the roller206can be appropriately held between the squeeze position and the protrusion312in the guide groove300, during the forward rotation of the tube pump200. Therefore, according to the present example, for example, the roller206can be prevented from colliding with the wall surface of the guide groove300at 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 groove300and the roller206for example.

In this case, for example, the protrusion312can also be regarded as regulating the movement of the roller206at the timing when the roller206is separated from the tube202for example. Furthermore, for example, the protrusion312can also be regarded as pressing the roller206, until the expanded state of the tube202is achieved for example.

In the tube pump200, a backward rotation operation of rotating the roller holder208in an orientation opposite to that during the forward rotation may be performed. In the case of the tube pump200of the present example, during the backward rotation, the roller holder208holds the shaft of the roller206to be more on the retracted position side than the protrusion312in the guide groove300. In this case, the retracted position side in the guide groove300can be regarded as, for example, the other end side opposite to the one end side where the shaft of the roller206is held during the forward rotation, or the like. With this configuration, for example, the roller holder208can be appropriately rotated backward, with the roller206appropriately retracted to a position to be not in contact with the tube202for example.

Although not illustrated inFIGS. 2A and 2BandFIGS. 3A and 3B, the tube pump200may further include, for example, an elastic member or the like that comes into contact with the roller206when the roller holder208rotates. For example, the elastic member comes into contact with the roller206moving in the rotation direction of the roller holder208to move the roller206toward the rear side in the rotation direction. Thus, the elastic member moves the roller206to the squeeze position during the forward rotation of the tube pump200, and moves the roller206to the retracted position during the backward rotation of the tube pump200, for example. As such an elastic member, a member that is the same as or similar to an elastic member used for known tube pumps can be suitably used.

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 protrusion312of the guide groove300is not limited to the shape specifically illustrated inFIG. 3Band can be changed in various manner, as long as large hitting sound can be appropriately prevented from being produced as a result of collision between the wall surface of the guide groove300and the roller206. In such a case, for example, the shape and arrangement of the protrusion312are preferably determined according to characteristics such as the size and elasticity of the tube202(seeFIGS. 3A and 3B).

In this regard, for the sake of prevention of the movement the roller206beyond the protrusion312, the protrusion312can 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 holder208causes the roller206to move from the squeeze position to the retracted position. However, the protrusion312having a large size or the like makes the movement of the roller206from 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 protrusion312is preferably determined while further taking the appropriate prevention of the backflow into consideration. In this case, the position and the shape of the protrusion312may 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 protrusion312may be set to a height with which the movement of the roller206from the squeeze position to the retracted position during the backward rotation is not hindered. In this case, the movement of the roller206is not hindered can be regarded as, for example, the problem of backflow of liquid not occurring due to the influence of the protrusion312, or the like. Furthermore, for preventing the backflow of liquid during the backward rotation, for example, a width of the guide groove300at the position of the protrusion312may 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 groove300may have a large width at the position of the protrusion312. with the recess314having a recessed amount overwhelming the protruding height of the protrusion312.

As can be understood from the above description and the like, the tube202may be used while switching between the forward rotation operation and the backward rotation operation as appropriate. The roller206moves beyond the protrusion312in the guide groove300, 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 groove300and the protrusion312can be regarded to be, for example, shapes for holding the roller206on the rear end side in the rotation direction of the roller holder208during each of the forward rotation and the backward rotation, and enabling the roller206to move over the protrusion312when the rotation direction of the roller holder208is changed. With this configuration, the forward rotation operation and the backward rotation operation of the tube pump200can be appropriately performed.

Furthermore, in the present example, the roller206at the retracted position during the backward rotation is maintained in a state of receiving no elastic force from the tube202, by not being in contact with the tube202. In this case, the prevention of the movement of the roller206using the protrusion312can be regarded to be, for example, particularly important during the forward rotation of the tube pump200. Thus, the protrusion312may 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 roller206can more appropriately move beyond the protrusion312when the backward rotation is switched to the forward rotation, while more surely preventing the roller206from moving over the protrusion312during the forward rotation.

As can be understood from the configuration illustrated inFIGS. 3A and 3Band the like, the guide groove300may be formed as a through hole penetrating the roller holder208formed as an integral object, for example. In this case, the wall surfaces of the guide grooves300such as the inner side surface302and the outer side surface304can be regarded as, for example, being made of a material that is the same as that of the roller holder208. On the other hand, in a modification of the configuration of the guide groove300, for example, as illustrated inFIG. 4A, the protrusion312may be formed as a separately formed retrofit member or the like.

FIGS. 4 and 5are diagrams illustrating modifications of the configuration of the guide groove300.FIGS. 4A to 4CandFIGS. 5A to 5Cillustrate various modifications of the configuration of the guide groove300. In the modification illustrated inFIG. 4A, the protrusion312is formed by a retrofit protruding member402. In this case, a through hole corresponding to a part of the guide groove300other than the protrusion312may be formed in the roller holder208(seeFIG. 3A), and then the protruding member402may be attached to a predetermined position of the through hole, for example. Also with this configuration, for example, the function of the protrusion312described above can be appropriately implemented. In this case, with the protrusion312formed by the protruding member402, for example, the protrusion312of various shapes can be formed more easily and appropriately. Thus, various adjustment on the characteristics of the protrusion312and the like are further enabled, for example. As the protruding member402, for example, a rubber member made of rubber or the like can be suitably used. The protruding member402is not limited to a rubber member, and members made of various materials may also be used. In this case, for example, an elastic material, or a material having a cushioning property superior to that of the material forming the wall surfaces of the guide groove300in parts other than the protrusion312may be used. The material having the superior cushioning property can be regarded, for example, as a material with a superior capability of absorbing an impact upon colliding with another member, or the like. With this configuration, in cases such as that when the shaft of the roller206collides with the protrusion312, an impact of the collision can be appropriately reduced for example. As the protruding member402, for example, a member made of a material that is the same as that of the wall surface of the guide groove300in parts other than the protrusion312may be used.

In the above description, the configuration in which the recess314is formed in accordance with the shape of the protrusion312is mainly illustrated and described. On the other hand, the shape of the recess314may have a shape that is not the same as that of the protrusion312. In this case, the shape of the recess314being the same as that of the protrusion312can be regarded as, for example, the surfaces defining the protruding shape of the protrusion312being the same as the surfaces defining the recessed shape of the recess314, or the like. More specifically, for example, as illustrated inFIG. 4B, the recess314may be formed to have a shape different from that of the protrusion312. In this case, for example, the recess314may have a shape that is easily processed compared with a case where the shape is the same as that of the protrusion312, or the like. For example, as illustrated inFIG. 4B, when the protrusion312is formed with a curved surface, the recess314may be formed to have a flat surface or the like. Furthermore, the recess314may be formed in a range wider than that facing the protrusion312, as illustrated inFIG. 4Bfor example. In the above description, the configuration in which the protrusion312is formed to have a curved surface is mainly illustrated and described. With such a configuration, for example, the protrusion312of various shapes can be appropriately formed. Thus, for example, the protrusion312with a shape with which the roller206is difficult to move toward the retracted position side beyond the protrusion312during the forward rotation, but can easily move beyond the protrusion312when the rotation direction of the roller holder208is changed can be appropriately formed. On the other hand, depending on the quality and the like required for the tube pump200, for example, the protrusion312having a flat surface may be formed as illustrated inFIG. 4C, or the like. With this configuration, the protrusion312can be more easily processed for example.

Furthermore, in the above description, the configuration in which the protrusion312is formed at a position slightly separated from the rear end of the guide groove300during the forward rotation is mainly illustrated and described. In this case, the protrusion312may be positioned to enable the shaft of the roller206to be held between the protrusion312and the rear end position of the guide groove300. More specifically, the protrusion312may be positioned to make a distance between the protrusion312and the rear end position of the guide groove300not smaller than the width of the shaft of the roller206. With this configuration, for example, the protrusion312can be appropriately prevented from affecting the roller206held at the squeeze position. Furthermore, in this case, the distance between the protrusion312and the rear end position of the guide groove300can be regarded as, for example, a distance between the rear end position of the guide groove300and a part of the inner side surface302that is raised relative to other parts due to the presence of the protrusion312, or the like. Furthermore, this distance can also be regarded as, for example, a distance between a position of the hem of the protrusion312where raising in a direction away from the center axis of the roller holder208starts and the rear end position of the guide groove300, or the like.

On the other hand, in a modification of the configuration of the guide groove300, for example, as illustrated inFIG. 5A, the protrusion312may be formed to protrude toward the outer side surface304from a position closer to the rear end of the guide groove300, or the like. In this case, for example, as indicated by a broken line in the figure, the protrusion312can be regarded as a part protruding toward the outer side surface304from a virtual position smoothly continuing to a part of the inner side surface302forming the retracted position side. In this case, for example, a state where the shaft of the roller206is held between the apex of the protrusion312and the rear end position of the guide groove300during the forward rotation can be regarded as the shaft of the roller206being held between the rear end position of the guide groove300and the protrusion312. Also with the protrusion312thus formed, for example, large hitting sound can be appropriately prevented from being produced due to collision between the wall surface of the guide groove300and the roller206, as long as the protrusion312is formed to make the shaft of the roller206held between the protrusion312and the rear end position of the guide groove300during the forward rotation. Also in the case of the modification illustrated inFIG. 5A, a part with a surface that is more separated from the center axis at part farther from the squeeze position can be regarded, for example, as the protrusion312, as in the configuration described above.

Considering such a feature of the protrusion312, the protrusion312can also be regarded, for example, as being formed in the guide groove300illustrated inFIG. 5B. More specifically, in the modification illustrated inFIG. 5B, the guide groove300has a bent portion316where the inner side surface302and the outer side surface304are bent. Thus, part of the inner side surface302can be regarded as a surface that is more separated from the center axis at a part farther from the squeeze position. Thus, also in this case, the guide groove300can be regarded as having the protrusion312. Also with this configuration, for example, large hitting sound can be appropriately prevented from being produced due to collision between the wall surface of the guide groove300and the roller206, as long as the protrusion312is formed to make the shaft of the roller206held between the protrusion312and the rear end position of the guide groove300during the forward rotation, for example.

As described above, for example, the guide groove300with the configuration illustrated inFIG. 5Bor the like can also be regarded as being capable of preventing large hitting sound from being produced due to the collision between the wall surface of the guide groove300and the roller206. However, in this case, the presence of the protrusion312affects the entirety of the inner side surface302and the outer side surface304, and this may result in the shape of the guide groove300being difficult to design or the like. Thus, for example, the protrusion312is preferably be of a shape defined by part of the inner side surface302protruding, as in the configuration illustrated inFIG. 3BandFIGS. 4A to 4Cfor example. The protrusion312is preferably formed to be less likely to affect the roller206at the squeeze position for example. In view of this, the protrusion312is more preferably formed at a position separated from the rear end of the guide groove300as in the configuration illustrated inFIG. 3BandFIGS. 4A to 4Cor the like.

Furthermore, in the above description, the configuration in which the protrusion312is formed at a position close the rear end of the guide groove300during the forward rotation is mainly illustrated and described. On the other hand, for the sake of attenuation of the momentum of the roller206before reaching the retracted position, the protrusion312may be formed at a position closer to the retracted position as illustrated inFIG. 5Cfor example, or the like. More specifically, the guide groove300with the configuration illustrated inFIG. 3BandFIGS. 4A to 4Cor the like can be regarded, for example, as having the protrusion312formed at a position closer to the rear end (rear end during the forward rotation) than to the front end (front end during the forward rotation) in the guide groove300. On the other hand, in the guide groove300illustrated inFIG. 5C, the protrusion312can be regarded, for example, as being formed at a position closer to the front end than to the rear end in the guide groove300, that is, at a position closer to the retracted position. Furthermore, in this case, the protrusion312may be formed at a position also separated from the retracted position at the front end of the guide groove300, to make the roller206come into contact with the protrusion312before reaching the retracted position.

When the protrusion312is formed as illustrated inFIG. 5C, at a timing when the roller206enters the non-contact zone after passing through the squeeze zone due to the forward rotation of the roller holder208, the roller206separated from the tube202moves toward the retracted position, and during the movement, the roller206collides with the protrusion312, for example. In this case, it is conceivable that hitting sound is produced by the collision between the protrusion312and the roller206. Still, in this case, it is possible to make the hitting sound produced when the protrusion312and the roller206come into contact with each other small, as compared with the hitting sound produced by the collision between the front end of the guide groove300and the roller206in a case where the protrusion312is not formed for example. More specifically, for example, when the roller206collides with the front end of the guide groove300in the state without the protrusion312formed, for example, the roller206collides with the wall surface of the guide groove300while moving substantially linearly, resulting in production of large hitting sound. On the other hand, when the protrusion312and the roller206come into contact with each other before the roller206reaches the retracted position, with the surface defining the protrusion312inclined with respect to the moving direction of the roller206for example, the impact of the collision can be reduced. Thus, it is possible to appropriately prevent production of large hitting sound for example. Also in this case, the protrusion312is preferably formed in such a manner that the roller206does not move beyond the protrusion312during the forward rotation. The protrusion312may also be formed to be in a shape with which the roller206moves beyond the protrusion312for example, or the like. In this case, for example, the protrusion312may be formed so as not to stop the movement of the roller206completely upon coming into contact with the roller206, but to attenuate the momentum of the movement of the roller206. Also with this configuration, the volume of the hitting sound produced by the contact between the protrusion312and the roller206can be appropriately reduced, for example. Furthermore, in this case, with the momentum of the movement of the roller206attenuated by the protrusion312, even when the roller206collides with the wall surface of the guide groove300at the front end of the guide groove300thereafter, the volume of the hitting sound produced by the collision can be appropriately reduced, for example.

To attenuate the momentum of the roller206before reaching the retracted position, also in a case where the protrusion312is formed at a position closer to the rear end of the guide groove300during the forward rotation in a further modification of the guide groove300, the protrusion312may be formed to have a shape with which the roller206moves beyond the protrusion312at a timing when the roller206enters 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 roller206with the protrusion312, the production of large hitting sound can be appropriately prevented, compared with a case where the protrusion312is 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 apparatus100(seeFIG. 1). In this case, the printing apparatus100can be regarded as an inkjet printer or the like that forms a two-dimensional image on a medium. On the other hand, according to a modification of the configuration of the printing apparatus100, a 3D printer (3D printing apparatus) or the like shaping a shaped object may be used as the printing apparatus100. Also in this case, with the tube pump200described above, the printing apparatus100featuring excellent quietness can be appropriately provided for example.

INDUSTRIAL APPLICABILITY

The present disclosure can be suitably used for, for example, a tube pump.