Up-down moving mechanism and inkjet printer

An up-down moving mechanism includes a support member; an up-down moving member that is formed separately from the support member and can be moved up and down with respect to the support member; a screw shaft for moving up and down the up-down moving member; a nut member that is screwed onto the screw shaft; a guide rail that guides the up-down moving member in a vertical direction; a guide block that slidably engages with the guide rail; and a gas spring that includes a cylinder and a piston rod biased in a direction projecting out from the cylinder, and that biases the up-down moving member toward an upper side with respect to the support member. To the support member, the screw shaft is rotatably attached, the guide rail is fixed, and the piston rod is attached.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit of Japanese Patent Application No. 2019-050767, filed on Mar. 19, 2019. 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 an up-down moving mechanism that moves up and down a predetermined up-down moving target object. The present disclosure also relates to an inkjet printer equipped with such an up-down moving mechanism.

DESCRIPTION OF THE BACKGROUND ART

An inkjet printer that performs printing on a print medium is conventionally known (see e.g., Japanese Unexamined Patent Publication No. 2009-248559). An inkjet printer described in Japanese Unexamined Patent Publication No. 2009-248559 includes a head unit with a plurality of inkjet heads arranged in the width direction of a transport line, a frame disposed above the head unit, and an actuator that moves up and down the head unit with respect to the frame. The actuator includes a servo motor and a screw that rotates by the power of the servo motor. The inkjet printer includes an air suspension that urges both end portions of the head unit toward the upper side. In this inkjet printer, the downward load of the head unit acting on the actuator is reduced by the air suspension.

SUMMARY

In the up-down moving mechanism that moves up and down a predetermined up-down moving target object such as a head unit described in Japanese Unexamined Patent Publication No. 2009-248559, it is preferable that the up-down moving target object be smoothly moved up and down.

The present disclosure thus provides an up-down moving mechanism that can smoothly move up and down an up-down moving target object in the up-down moving mechanism for moving up and down a predetermined up-down moving target object. The present disclosure also provides an inkjet printer equipped with such an up-down moving mechanism.

In order to solve the problems described above, an up-down moving mechanism of the present disclosure relates to an up-down moving mechanism that moves up and down a predetermined up-down moving target object, the up-down moving mechanism including a support member; an up-down moving member that is formed separately from the support member and coupled to the up-down moving target object, and that can be moved up and down with respect to the support member; a screw shaft for moving up and down the up-down moving member; a nut member that is screwed onto the screw shaft; a guide rail that guides the up-down moving member in a vertical direction; a guide block that slidably engages with the guide rail; and a gas spring that includes a cylinder and a piston rod biased in a direction projecting out from the cylinder, and that biases the up-down moving member toward an upper side with respect to the support member; in which to any one of the support member and the up-down moving member, the screw shaft is rotatably attached, the guide rail is fixed, and any one of the cylinder and the piston rod is attached.

In the up-down moving mechanism of the present disclosure, to any one of the support member and the up-down moving member, the screw shaft is rotatably attached, the guide rail is fixed, and any one of the cylinder and the piston rod of the gas spring is attached. That is, in the present disclosure, the screw shaft is rotatably attached, the guide rail is fixed, and any one of the cylinder and the piston rod is attached to a common member.

Therefore, in the present disclosure, the relative position accuracy between members of each of the screw shaft for moving up and down the up-down moving member, the guide rail for guiding the up-down moving member in the vertical direction, and the gas spring that biases the up-down moving member toward the upper side with respect to the support member can be increased. Therefore, in the present disclosure, the up-down moving member can be smoothly moved up and down with respect to the support member, and as a result, the up-down moving target object coupled to the up-down moving member can be smoothly moved up and down.

Preferably, in the present disclosure, to the support member, the screw shaft is rotatably attached, the guide rail is fixed, and any one of the cylinder and the piston rod is attached; and to the up-down moving member, the nut member is attached, the guide block is fixed, and other one of the cylinder and the piston rod is attached. With such a configuration, the weight of the structural object moved up and down with respect to the support member can be reduced compared to a case where the screw shaft and the guide rail are attached to the up-down moving member.

Preferably, in the present disclosure, the support member is a single member formed in a flat plate shape; a thickness direction of the support member is orthogonal to the vertical direction; and to one surface of the support member, the screw shaft is rotatably attached, the guide rail is fixed, and any one of the cylinder and the piston rod is attached. With such a configuration, the relative position accuracy between the members of each of the screw shaft, the guide rail and the gas springs can be further increased since the screw shaft, the guide rail, and the cylinder or the piston rod are attached to one surface of the support member formed as a plane. Therefore, the up-down moving member can be more smoothly moved up and down with respect to the support member.

Preferably in the present disclosure, the up-down moving mechanism further includes one screw shaft, two guide rails, and two gas springs; in which assuming that a direction orthogonal to the thickness direction of the support member and the vertical direction is a width direction of the support member, the screw shaft is rotatably attached to the support member at a center position of the support member in the width direction of the support member, each of the two gas springs is disposed on each side of the screw shaft in the width direction of the support member, and each of the two guide rails is fixed to the support member at each outer side of the two gas springs in the width direction of the support member.

With such a configuration, the up-down moving member can be biased toward the upper side in a balanced manner with respect to the support member, and the up-down moving member can be guided in a vertical direction in a balanced manner with respect to the support member. Therefore, the up-down moving member can be moved up and down in a balanced manner with respect to the support member, and as a result, the up-down moving member can be moved up and down more smoothly with respect to the support member.

Preferably, in the present disclosure, the screw shaft, the guide block, and the gas springs are disposed at substantially the same position in the thickness direction of the support member. With such a configuration, the up-down moving mechanism can be thinned in the thickness direction of the support member.

In the present disclosure, for example, the up-down moving mechanism includes a motor that rotates the screw shaft, and the motor is attached to the support member.

Preferably, in the present disclosure, the up-down moving mechanism includes an electromagnetic brake for stopping the rotation of the screw shaft, and a main body of the electromagnetic brake is attached to the support member. With such a configuration, the relative position accuracy between the screw shaft and the electromagnetic brake can be increased. Therefore, for example, the relative position accuracy between the disc of the electromagnetic brake fixed to the screw shaft and the main body of the electromagnetic brake can be increased, and as a result, brake can be reliably applied to the screw shaft by the electromagnetic brake.

The up-down moving mechanism of the present disclosure can be used in an inkjet printer. The inkjet printer includes, for example, two up-down moving mechanisms, an inkjet head that ejects ink droplets onto a print medium, a carriage on which the inkjet head is mounted, a carriage holding member that holds the carriage to be movable in a main scanning direction, and a table on which the print medium is placed, in which each of the two up-down moving mechanisms is disposed on each of both end sides of the table in the main scanning direction; the carriage holding member is the up-down moving target object; an end of the carriage holding member in the main scanning direction is coupled to the up-down moving member; the support member is coupled to the table; and the two up-down moving mechanisms move up and down the carriage holding member with respect to the table. In such an inkjet printer, the up-down moving member can be smoothly moved up and down with respect to the support member, and thus, the carriage holding member coupled to the up-down moving member can be smoothly moved up and down with respect to the table to which the support member is coupled.

Therefore, in the up-down moving mechanism of the present disclosure, the up-down moving target object can be smoothly moved up and down. Furthermore, in the inkjet printer of the present disclosure, the carriage holding member can be moved up and down smoothly with respect to the table.

DESCRIPTION OF EMBODIMENTS

(Schematic Configuration of Inkjet Printer)

FIG. 1is a front view of an inkjet printer1according to an embodiment of the present disclosure.

The inkjet printer1(hereinafter referred to as “printer1”) of the present embodiment is, for example, a business inkjet printer that performs printing on a print medium such as print paper. The printer1of the present embodiment is a so-called flat bed type inkjet printer. The printer1includes an inkjet head3that ejects ink droplets onto a print medium, a carriage4on which the inkjet head3is mounted, a Y bar5serving as a carriage holding member that holds the carriage4so as to be movable in the main scanning direction, and a carriage moving mechanism (not shown) for moving the carriage4in the main scanning direction with respect to the Y bar5.

The printer1also includes a table6on which a print medium is placed, and support legs7that support the table6. Furthermore, the printer1includes an up-down moving mechanism8that moves up and down the Y bar5with respect to the table6, and a slide mechanism9that slides the Y bar5with respect to the table6in the sub-scanning direction orthogonal to the vertical direction and the main scanning direction. In the following description, the main scanning direction (Y direction inFIG. 1etc.) is assumed as “left-right direction” and the sub-scanning direction (X direction inFIG. 1etc.) is assumed as “front-back direction”. Furthermore, the Y1 direction side inFIG. 1or the like which is one side in the left-right direction is referred to as the “right” side, and the Y2 direction side inFIG. 1, which is the opposite side, is referred to as the “left” side.

The carriage4is disposed on the upper side of the table6. The inkjet head3ejects ink droplets from the upper side toward the print medium placed on the upper surface of the table6. The ink discharged from the inkjet head3is, for example, an ultraviolet curable ink (UV ink). The carriage4is mounted with an ultraviolet irradiator that irradiates the ink ejected from the inkjet head3with ultraviolet rays. The carriage moving mechanism includes, for example, a motor, a driving pulley that rotates by the power of the motor, a driven pulley, and a belt applied across the driving pulley and the driven pulley. A part of the belt is fixed to the carriage4.

The Y bar5is formed in a rectangular parallelepiped shape elongated in the left-right direction. Both left and right end portions of the Y bar5are supported from below by a Y bar support member10. The table6is formed in a rectangular thick plate shape. The table6is disposed between the two Y bar support members10in the left-right direction. The support legs7support, for example, both front and rear end portions of the table6from below.

The slide mechanism9is disposed on each of the left and right ends of the table6. In other words, the printer1includes two slide mechanisms9. The slide mechanism9includes a motor and a ball screw. The fixed side of the slide mechanism9is fixed to the table6. On the movable side (slide side) of the slide mechanism9, a support member14, which will be described later, forming the up-down moving mechanism8is fixed. The slide mechanism9moves the up-down moving mechanism8in the front-back direction together with the Y bar5, the Y bar support member10, and the like.

The up-down moving mechanism8is disposed on each of the left and right ends of the table6. That is, the printer1includes two up-down moving mechanisms8, and the two up-down moving mechanisms8move up and down the Y bar5with respect to the table6. The Y bar5of the present embodiment is an up-down moving target object. Hereinafter, a specific configuration of the up-down moving mechanism8will be described. In the following description, the configuration of the up-down moving mechanism8disposed on the left side of the two up-down moving mechanisms8disposed on the left and right ends of the table6will be described.

FIG. 2is a perspective view for explaining the configuration of the up-down moving mechanism8shown inFIG. 1.FIGS. 3A and 3Bare side views for explaining the configuration and operation of the up-down moving mechanism8from the E-E direction ofFIG. 2.FIGS. 4A and 4Bare side views for explaining the configuration and operation of the up-down moving mechanism8from the F-F direction ofFIG. 2.

The up-down moving mechanism8includes a support member14and an up-down moving member15that is formed separately from the support member14and can be moved up and down with respect to the support member14. The up-down moving mechanism8includes a ball screw including a screw shaft (lead screw)16for moving up and down the up-down moving member15and a nut member17screwed to the screw shaft16, an LM guide having a guide rail18for guiding the up-down moving member15in the vertical direction and a guide block19that slidably engages with the guide rail18, and a gas spring20for urging the up-down moving member15to the upper side with respect to the support member14. InFIGS. 2, 3A and 3B, for the sake of convenience of explanation, the outer shape of the up-down moving member15is indicated by a broken line, and the up-down moving member15is illustrated in a transparent state.

The up-down moving mechanism8of the present embodiment includes one screw shaft16, two guide rails18, and two gas springs20. One nut member17is screwed into the screw shaft16. Two guide blocks19are engaged with one guide rail18. That is, the up-down moving mechanism8includes four guide blocks19. The up-down moving mechanism8includes a motor22that rotates the screw shaft16and an electromagnetic brake23that stops the rotation of the screw shaft16.

The support member14is formed in a rectangular flat plate shape. That is, the support member14is a single member formed in a flat plate shape. The support member14is disposed so that the long side direction of the support member14formed in a rectangular shape and the vertical direction coincide with each other. Furthermore, the support member14is disposed so that the thickness direction of the support member14and the left-right direction coincide. That is, the left-right direction (Y direction) is the thickness direction of the support member14, and the thickness direction of the support member14is orthogonal to the vertical direction. Note that, the front-back direction (X direction) of the present embodiment is the width direction of the support member14orthogonal to the thickness direction of the support member14and the vertical direction.

At the center portion of the support member14in the front-back direction, three through holes14ato14cthat penetrate through the support member14in the left-right direction are formed. The through hole14ais formed at the lower end portion of the support member14. The through hole14bis formed above the through hole14a, and the through hole14cis formed above the through hole14b. Thin plate-like side plates25are fixed to both front and back end faces of the support member14. The left end face of the side plate25is disposed on the right side of the left surface of the support member14. The right surface of the support member14is fixed to the movable side of the slide mechanism9. That is, the support member14is coupled to the table6by way of the slide mechanism9.

Similar to the support member14, the up-down moving member15is formed in a rectangular flat plate shape. That is, the up-down moving member15is a single member formed in a flat plate shape. The up-down moving member15is disposed so that the long side direction of the up-down moving member15formed in a rectangular shape coincides with the vertical direction. Furthermore, the up-down moving member15is disposed so that the thickness direction of the up-down moving member15coincides with the left-right direction. The up-down moving member15is disposed on the left side of the support member14. A through hole15apenetrating the up-down moving member15in the left-right direction is formed at the center portion of the up-down moving member15in the front-back direction. In addition, a notch15bfor avoiding interference between the electromagnetic brake23, a bearing29and a pulley30, which will be described later, and the up-down moving member15is formed at the lower end of the center portion of the up-down moving member15in the front-back direction.

Thin plate-like side plates26are fixed to both front and back end faces of the up-down moving member15. The left end face of the side plate26is disposed on the right side of the left surface of the up-down moving member15. Furthermore, the width in the front-back direction of the up-down moving member15is wider than the width in the front-back direction of the support member14, and the two side plates26are disposed on the outer side of the two side plates25in the front-back direction. A support plate27formed in a flat plate shape is fixed to the upper end face of the up-down moving member15. The lower surface of the Y bar support member10is fixed to the upper surface of the support plate27. In other words, the up-down moving member15is coupled to the Y bar5which is the up-down moving target object through the support plate27and the Y bar support member10. Specifically, the left end portion of the Y bar5is coupled to the up-down moving member15.

The screw shaft16is disposed so that the axial direction of the screw shaft16and the vertical direction coincide. The screw shaft16is rotatably held by the bearing29. The bearing29is attached to the left surface of the support member14. That is, the screw shaft16is rotatably attached to the left surface of the support member14through the bearing29. Furthermore, the screw shaft16is rotatably attached to the support member14at the center position of the support member14in the front-back direction. The bearing29holds the lower end side of the screw shaft16. The nut member17is attached to the up-down moving member15. Specifically, the nut member17is fixed to the right surface of the up-down moving member15. In addition to the bearing29, the up-down moving mechanism8may include a bearing that rotatably holds the upper end side of the screw shaft16.

The motor22is a servo motor. The motor22is attached to the support member14. Specifically, the motor22is fixed to the right surface of the support member14. The output shaft of the motor22projects out to the lower side. A pulley is fixed to the output shaft of the motor22, and a pulley30is also fixed to the lower end portion of the screw shaft16. A belt31is applied across a pulley fixed to the output shaft of the motor22and the pulley30. A part of the pulley30and a part of the belt31are disposed in the through hole14aof the support member14.

The electromagnetic brake23is a non-excitation operation type electromagnetic brake in which a brake force acts at the time of non-energization. The main body of the electromagnetic brake23is attached to the support member14. Specifically, the main body of the electromagnetic brake23is fixed to the left surface of the support member14. A disk of the electromagnetic brake23is fixed to the lower end portion of the screw shaft16. When the screw shaft16is rotated, the electromagnetic brake23is in an energized state so that the brake force of the electromagnetic brake23does not act.

On the other hand, when maintaining a stopped state of the screw shaft16, the electromagnetic brake23is in a non-energized state so that the brake force of the electromagnetic brake23acts. When the brake force of the electromagnetic brake23is acting, a state in which the up-down moving member15is stopped with respect to the support member14is maintained, and a distance in the vertical direction between the Y bar5and the table6is kept constant. For example, when printing on a print medium, the electromagnetic brake23is in a non-energized state, and the distance in the vertical direction between the Y bar5and the table6is kept constant.

The guide rail18is disposed so that the longitudinal direction of the guide rail18coincides with the vertical direction. The guide rail18is fixed to the support member14. Specifically, the guide rail18is fixed to the left surface of the support member14. Furthermore, each of the two guide rails18is fixed to each of both front and back ends of the support member14. The guide block19is fixed to the up-down moving member15. Specifically, the guide block19is fixed to the right surface of the up-down moving member15, and is engaged with the guide rail18from the left side.

The gas spring20includes a cylinder33that forms a main body of the gas spring20and a piston rod34that is biased in a direction projecting out from the cylinder33. The piston rod34is biased in a direction projecting out from the cylinder33by the compressed gas sealed inside the cylinder33. The gas spring20is disposed so that the longitudinal direction of the gas spring20coincides with the vertical direction. The gas spring20is disposed so that the piston rod34projects out downward.

The distal end portion (lower end portion) of the piston rod34is turnably held by the rod holding member35. The distal end portion of the piston rod34can be turned with respect to the rod holding member35with the front-back direction as the axial direction of turning. The rod holding member35is fixed to the support member14. That is, the piston rod34is attached to the support member14through the rod holding member35. Specifically, the rod holding member35is fixed to the lower end side of the left surface of the support member14, and the piston rod34is attached to the left surface of the support member14through the rod holding member35.

The upper end portion of the cylinder33is turnably held by the cylinder holding member36. The upper end portion of the cylinder33can be turned with respect to the cylinder holding member36with the front-back direction as the axial direction of turning. The cylinder holding member36is fixed to the up-down moving member15. That is, the cylinder33is attached to the up-down moving member15through the cylinder holding member36. Specifically, the cylinder holding member36is fixed to the upper end side of the right surface of the up-down moving member15, and the cylinder33is attached to the right surface of the up-down moving member15through the cylinder holding member36.

Each of the two gas springs20is disposed on each of both the front and back sides of the screw shaft16. The gas spring20is disposed between the screw shaft16and the guide rail18in the front-back direction. That is, each of the two guide rails18is disposed on each of the front and back outer sides of the two gas springs20. In the present embodiment, as shown inFIG. 2, the screw shaft16, the guide block19, and the gas spring20are disposed at substantially the same position in the left-right direction.

In the up-down moving mechanism8, when the motor22is driven, the up-down moving member15moves up and down with respect to the support member14along the guide rail18. Specifically, when the motor22is driven, the up-down moving member15moves up and down with respect to the support member14between the upper limit position shown inFIGS. 3A and 4Aand the lower limit position shown inFIGS. 3B and 4B. That is, when the motor22is driven, the Y bar5moves up and down with respect to the table6. The up/down moving amount of the up-down moving member15with respect to the support member14is, for example, 150 (mm). Furthermore, the biasing force of the gas spring20becomes maximum when the up-down moving member15is at the lower limit position, and becomes smaller as the up-down moving member15rises from the lower limit position.

(Main Effect of the Present Embodiment)

As described above, in the present embodiment, the screw shaft16is rotatably attached, the guide rail18is fixed, and the piston rod34of the gas spring20is attached to the support member14. Therefore, in the present embodiment, the relative position accuracy between members of each of the screw shaft16for moving up and down the up-down moving member15, the guide rail18for guiding the up-down moving member15in the vertical direction, and the gas spring20that biases the up-down moving member15toward the upper side with respect to the support member14can be increased. Therefore, in the present embodiment, the up-down moving member15can be smoothly moved up and down with respect to the support member14, and as a result, the Y bar5coupled to the up-down moving member15can be smoothly moved up and down with respect to the table6to which the support member14is coupled.

In particular, in the present embodiment, the screw shaft16is rotatably attached, the guide rail18is fixed, and the piston rod34is attached to the left surface of the support member14which is a flat surface, so that the relative position accuracy between members of each of the screw shaft16, the guide rail18, and the gas spring20can be further increased. Therefore, in the present embodiment, the up-down moving member15can be more smoothly moved up and down with respect to the support member14.

Furthermore, in the present embodiment, the screw shaft16is rotatably attached to the support member14at the center position of the support member14in the front-back direction, and each of the two gas springs20is disposed on both front and back sides of the screw shaft16, and each of the two guide rails18are respectively disposed on the front and Back outer sides of the two gas springs20. Therefore, in the present embodiment, the up-down moving member15can be biased toward the upper side in a balanced manner with respect to the support member14, and the up-down moving member15can be guided in a vertical direction in a balanced manner with respect to the support member14. Therefore, in the present embodiment, the up-down moving member15can be moved up and down in a balanced manner with respect to the support member14, and as a result, the up-down moving member15can be moved up and down more smoothly with respect to the support member14.

In the present embodiment, the screw shaft16, the guide block19, and the gas spring20are disposed at substantially the same position in the left-right direction. Therefore, in the present embodiment, the up-down moving mechanism8can be thinned in the left-right direction.

In the present embodiment, the main body of the electromagnetic brake23is fixed to the support member14to which the screw shaft16is attached. Therefore, in the present embodiment, the relative position accuracy between the screw shaft16and the electromagnetic brake23can be increased. Therefore, in the present embodiment, the relative position accuracy between the disc of the electromagnetic brake23fixed to the screw shaft16and the main body of the electromagnetic brake23can be increased, and as a result, brake can be reliably applied on the screw shaft16by the electromagnetic brake23.

Other Embodiments

The embodiment described above is an example of a preferred embodiment of the present disclosure, but the present disclosure is not limited thereto, and various modifications can be made without changing the gist of the present disclosure.

In the embodiment described above, the cylinder33may be attached to the support member14and the piston rod34may be attached to the up-down moving member15. In the mode described above, the screw shaft16is rotatably attached and the guide rail18is fixed to the up-down moving member15, and the nut member17is attached and the guide block19is fixed to the support member14. However, as described above, the weight of the structural object that moves up and down relative to the support member14can be reduced if the screw shaft16and the guide rail18are attached to the support member14.

In the embodiment described above, the two gas springs20may be disposed on the front and back outer sides of the two guide rails18, respectively. Furthermore, in the embodiment described above, any one of the screw shaft16, the guide block19and the gas spring20may be disposed at a position shifted in the left-right direction, or the screw shaft16, the guide block19and the gas spring20may be disposed at positions shifted from each other in the left-right direction.

In the embodiment described above, the printer1may be a shaping device that forms a three-dimensional object on the table6. Furthermore, in the embodiment described above, the up-down moving mechanism8moves up and down the Y bar5, but the up-down moving mechanism8may, for example, move up and down the table6. In this case, the table6is an up-down moving target object. Furthermore, the up-down moving mechanism8to which the present disclosure is applied may be used in devices other than the printer1.