JP2019104116A - Head moving mechanism and printer - Google Patents

Abstract

To suppress wear of a cam and a cam follower in a head moving mechanism moving a plurality of print heads.SOLUTION: A head moving mechanism 6 comprises: a first holding part 61c holding a first print head 36c and having a first cam follower 63c; a second holding part 61d holding a second print head 36d and having a second cam follower 63d; and a cam 65 receiving driving force of an actuator 68 and rotating around a cam shaft 66. A first bearing 64c brought into contact with the cam 65 is attached to the first cam follower 63c, and the second cam follower 63d is interlocked with the first cam follower 63c. The first bearing 64c rotates by rotation of the cam 65, and the first cam follower 63c is displaced with respect to the cam shaft 66. The first print head 36c moves in a first direction, on the other hand, the second cam follower 63d interlocked with the first cam follower 63c is displaced with respect to the cam shaft 66 and the first cam follower 63c, and the second print head 36d moves in a second direction.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a head moving mechanism and a printing apparatus.

  Conventionally, there has been proposed a printing apparatus which records an image by discharging inks of different colors onto a recording medium from a plurality of print heads (see, for example, Patent Document 1). In such a printing apparatus, the recording medium is wound around a cylindrical platen drum under tension, and supported by the surface (curved surface) of the platen drum. Each print head is configured to move in a direction perpendicular to the surface of the platen drum. That is, assuming that the movement direction of the first print head is a first direction, the movement direction of the second print head adjacent to the first print head is a second direction different from the first direction.

  In recent years, a mechanism for moving a plurality of print heads moving in different directions as described above using one cam has been proposed (see, for example, Patent Document 2). The mechanism described in Patent Document 2 moves the print heads connected to the respective cam followers in different directions by moving the two cam followers up and down with the rotation of one cam. By adopting such a mechanism, it is not necessary to separately provide a cam and a head moving mechanism for each print head, and therefore, downsizing and cost reduction of the apparatus can be achieved, and positioning of the print head due to individual differences of cams It is said that errors can be prevented from occurring.

JP, 2011-67964, A Patent No. 6008091

  However, if a mechanism such as that described in Patent Document 2 is employed, two cam followers contact the outer peripheral surface of one cam, and there is a problem that the cams and cam followers may be worn with repeated use. The As the wear of the cam and the cam follower progresses, the position of the print head gradually changes, and the nozzle at the tip of the print head may contact the recording medium, which may damage the recorded image or damage the nozzle. The

  The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress wear of a cam and a cam follower in a head moving mechanism that moves a plurality of print heads.

  In order to achieve the above object, a head moving mechanism according to the present invention comprises a first holding portion for holding the first print head movably in a first direction, and a second holding mechanism that is inclined with respect to the first direction. A second holding unit for movably holding the print head, an actuator for generating a driving force for moving the first print head and the second print head, and a driving force of the actuator to rotate around a cam shaft A first cam follower attached to the first holding portion, and a second cam follower attached to the second holding portion, the first cam follower being attached with a first bearing in contact with the cam The second cam follower is configured to contact the first cam follower or interlock with the first cam follower via the interlocking member, and to be displaced relative to the first cam follower The first bearing in contact with the cam is rotated by the rotation of the cam, and the first cam follower is displaced with respect to the cam shaft, whereby the first print head is moved in the first direction. On the other hand, the second cam follower contacting or interlocking with the first cam follower is displaced with respect to the cam shaft and the first cam follower, whereby the second print head is moved in the second direction.

  With this configuration, when the first print follower is moved by displacing the first cam follower by the rotation of the cam, the cam can be brought into contact with the first bearing. Further, when the second cam follower is displaced to move the second print head, the second cam follower can be brought into contact with or interlocked with the first cam follower. Therefore, direct contact between the cam and the first cam follower and the second cam follower can be prevented, so that wear of the cam, the first cam follower and the second cam follower can be suppressed.

  In the head moving mechanism according to the present invention, a plane which causes at least one of the first cam follower and the second cam follower to interlock the second cam follower with the first cam follower and realize displacement of the second cam follower with respect to the first cam follower A part can be provided. In such a case, the virtual plane including the flat portion may be orthogonal to the virtual plane including the straight line bisecting the angle formed by the first straight line parallel to the first direction and the second straight line parallel to the second direction. it can.

  When this configuration is adopted, the movement distance of the first cam follower (first print head) in the first direction along with the rotation of the cam is equal to the movement distance of the second cam follower (second print head) in the second direction. be able to.

  In the head moving mechanism according to the present invention, the second bearing as the interlocking member is attached to one of the first cam follower and the second cam follower, and a flat portion contacting the second bearing is attached to the other of the first cam follower and the second cam follower. It can be provided.

  When this configuration is adopted, the second bearing (the interlocking member) attached to the first cam follower (the second cam follower) is brought into contact with the flat portion provided in the second cam follower (the first cam follower). The two cam followers can be interlocked with the first cam followers, and the second cam followers can be displaced with respect to the first cam followers.

  In the printing apparatus according to the present invention, a roller provided rotatably, a first print head for discharging a first liquid from a first direction to a recording medium wound around the surface of the roller, and a surface of the roller A second print head for ejecting the second liquid from the second direction to the recording medium to be wound, and moving the first print head in the first direction while moving the second print head in the second direction And a head moving mechanism. Here, the first direction and the second direction can be directions extending radially from the rotation axis of the roller.

The top view (figure seen from the upper side) which shows the layout of the printing apparatus equipped with the head moving mechanism which concerns on embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS The front view (figure seen from the front side) which shows the whole structure of the printing apparatus equipped with the head moving mechanism which concerns on embodiment of this invention. The perspective view at the time of seeing the head moving mechanism which concerns on embodiment of this invention from the front side. FIG. 2 is a partially enlarged perspective view of a part of the head moving mechanism according to the embodiment of the present invention as viewed from the rear side. The rear view (figure seen from the back side) of the head moving mechanism which concerns on embodiment of this invention. The figure for demonstrating arrangement | positioning of the plane part of the 2nd cam follower of the head moving mechanism which concerns on embodiment of this invention. FIG. 7 is a view showing the operation of the head moving mechanism according to the embodiment of the present invention. FIG. 10 is a partial enlarged perspective view showing a modified example of the head moving mechanism according to the embodiment of the present invention.

  Hereinafter, an embodiment of a head moving mechanism according to the present invention will be described with reference to the drawings. The present invention is not limited by the embodiments.

  FIG. 1 is a plan view showing the layout of a printing apparatus 1 equipped with a head moving mechanism according to an embodiment of the present invention. FIG. 2 is a front view for explaining the overall configuration of the printing apparatus 1 shown in FIG. In the printing apparatus 1, the feeding unit 2, the process unit 3, and the winding unit 4 are arranged in the left-right direction on the front side of the apparatus, and the maintenance unit 5 is disposed on the rear side of the process unit 3. The 3U is movable relative to the maintenance unit 5 integrally. In these drawings and the drawings to be described later, a three-dimensional coordinate system corresponding to the lateral direction X, the longitudinal direction Y, and the vertical direction Z of the printing apparatus 1 is employed.

  As shown in FIG. 2, in the printing apparatus 1, the delivery unit 2 and the take-up unit 4 each have a delivery shaft 20 and a take-up shaft 40. Then, both ends of the sheet S are wound around the feeding unit 2 and the winding unit 4 in a roll shape, and are stretched between them. The sheet S is conveyed from the delivery unit 2 to the processing unit 3 along the path Pc thus stretched and subjected to printing processing by the process unit 3U, and then conveyed to the winding unit 4. The types of sheet S corresponding to the "recording medium" of the present invention are roughly classified into paper-based and film-based. Specific examples thereof include high-quality paper, cast paper, art paper, coated paper and the like in the paper system, and synthetic paper, PET (polyethylene terephthalate), PP (polypropylene) and the like in the film system. In the following description, of the both sides of the sheet S, the side on which an image is recorded is referred to as the front side, and the opposite side is referred to as the back side.

  The feeding unit 2 includes a feeding shaft 20 around which the end of the sheet S is wound, and a driven roller 21 around which the sheet S pulled from the feeding shaft 20 is wound. The delivery shaft 20 winds and supports the end of the sheet S with the surface of the sheet S facing outward. Then, the delivery shaft 20 is rotated clockwise on the sheet surface of FIG. 2 so that the sheet S wound around the delivery shaft 20 is delivered to the processing unit 3 via the driven roller 21. Incidentally, the sheet S is wound around the feeding shaft 20 via a core tube (not shown) which is detachably attached to the feeding shaft 20. Therefore, when the sheet S of the feeding shaft 20 is used up, a new core tube around which the rolled sheet S is wound can be attached to the feeding shaft 20 so that the sheet S of the feeding shaft 20 can be replaced. It has become. The symbol Se in FIG. 2 is an edge sensor that detects the end of the sheet S in the width direction between the driven roller 21 and the front drive roller 31.

  The processing unit 3 supports the sheet S fed from the feeding unit 2 by the platen drum 30, and appropriately processes the sheet S by the process unit 3U disposed along the outer peripheral surface of the platen drum 30, thereby forming an image on the sheet S. It is something to print. In the process unit 3, the front drive roller 31 and the rear drive roller 32 are provided on both sides of the platen drum 30, and the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 is supported by the platen drum 30. To receive a print of the image.

  The front drive roller 31 has a plurality of minute projections formed by thermal spraying on the outer peripheral surface, and winds the sheet S fed from the feeding unit 2 from the back surface side. Then, the front drive roller 31 rotates clockwise on the sheet surface of FIG. 2 to convey the sheet S fed out from the feeding unit 2 to the downstream side of the conveyance path. A nip roller 31 n is provided for the front drive roller 31. The nip roller 31 n is in contact with the surface of the sheet S in a state of being biased toward the front drive roller 31, and sandwiches the sheet S with the front drive roller 31. By this, the frictional force between the front drive roller 31 and the sheet S is secured, and the conveyance of the sheet S by the front drive roller 31 can be reliably performed.

  The platen drum 30 is a cylindrical drum rotatably supported around a pivot shaft 301 extending in the Y direction by a support mechanism (not shown), and is conveyed from the front drive roller 31 to the rear drive roller 32. The sheet S is wound from the back side. The platen drum 30 supports the sheet S from the back surface side while being rotationally driven in the conveyance direction Ds of the sheet S by receiving a frictional force with the sheet S. Incidentally, in the process unit 3, driven rollers 33 and 34 configured to fold back the sheet S on both sides of the winding portion around the platen drum 30 are provided. Among these, the driven roller 33 wraps the surface of the sheet S between the front drive roller 31 and the platen drum 30, and folds back the sheet S. On the other hand, the driven roller 34 wraps the surface of the sheet S between the platen drum 30 and the rear drive roller 32, and folds back the sheet S. As described above, by folding the sheet S back and forth in the transport direction Ds with respect to the platen drum 30, a long winding portion of the sheet S on the platen drum 30 can be secured.

  The rear driving roller 32 has a plurality of minute projections formed by thermal spraying on the outer peripheral surface, and winds the sheet S conveyed from the platen drum 30 via the driven roller 34 from the rear surface side. Then, the rear driving roller 32 conveys the sheet S to the winding unit 4 by rotating clockwise on the sheet surface of FIG. 2. A nip roller 32 n is provided for the rear drive roller 32. The nip roller 32 n is in contact with the surface of the sheet S in a state of being biased toward the rear drive roller 32, and sandwiches the sheet S with the rear drive roller 32. By this, the frictional force between the rear drive roller 32 and the sheet S is secured, and the conveyance of the sheet S by the rear drive roller 32 can be reliably performed.

  Thus, the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 is supported by the outer peripheral surface of the platen drum 30. In the processing unit 3, a process unit 3 U is provided to print a color image on the surface of the sheet S supported by the platen drum 30. The process unit 3U has a front plate 35a and a back plate 35b (see FIG. 3) provided in a pair of front and rear. Each of the plates 35a and 35b has an arc shape along the outer peripheral surface of the platen drum 30, and is connected to each other by a connecting member (not shown) to form a unit frame. The components (print heads 36a to 36e, UV lamps 37a and 37b, and a head moving mechanism) of the process unit 3U are attached to the unit frame as described below.

  Four print heads 36a to 36d corresponding to yellow, cyan, magenta and black are arranged in the transport direction Ds in this color order. More specifically, the four print heads 36 a to 36 d are disposed radially from the pivot shaft 301 of the platen drum 30. Further, among the print heads 36a to 36d, the two print heads 36a and 36b disposed on the upstream side in the transport direction Ds are positioned with respect to the sheet S which is moved by one head moving mechanism and wound around the platen drum 30. Be done. The two print heads 36 c and 36 d disposed downstream are also moved by another head moving mechanism and positioned with respect to the sheet S wound around the platen drum 30. Then, the four print heads 36a to 36d are moved and positioned by these two head moving mechanisms, whereby the distance between the nozzle tip (ink discharge port) of the print heads 36a to 36d and the sheet S, a so-called paper gap Can be set to an appropriate value. In this manner, each print head 36 a to 36 d discharges ink to the sheet S wound around the outer periphery of the platen drum 30 in a state where the paper gap is adjusted, thereby forming a color image on the surface of the sheet S Be done. The configuration and operation of the head moving mechanism will be described in detail later.

  As liquids, such as ink used by printing head 36a-36d, and a recording liquid, UV (ultraviolet) ink (photocurable ink) hardened | cured by irradiating an ultraviolet-ray (light) is used. Therefore, in the process unit 3U, UV lamps 37a and 37b are provided in order to cure the ink and fix it on the sheet S. The ink curing is performed in two stages of temporary curing and main curing. A temporary curing UV lamp 37a is disposed between each of the plurality of print heads 36a to 36d. That is, the UV lamp 37a cures (temporarily cures) the ink to such an extent that the shape of the ink does not collapse by irradiating a relatively weak ultraviolet ray, and does not completely cure the ink. On the other hand, a UV lamp 37b for main curing is provided on the downstream side of the plurality of print heads 36a to 36d in the transport direction Ds. That is, the UV lamp 37 b completely cures (main cures) the ink by irradiating ultraviolet rays stronger than the UV lamp 37 a. By thus performing temporary curing and main curing, it is possible to fix the color image formed by the plurality of print heads 36 a to 36 d on the surface of the sheet S.

  Further, a print head 36e is provided downstream of the UV lamp 37b in the transport direction Ds. The print head 36 e opposes the surface of the sheet S wound around the platen drum 30 with a slight clearance, and discharges the transparent UV ink on the surface of the sheet S by the inkjet method. That is, the transparent ink is further discharged to the color image formed by the print heads 36 a to 36 d for four colors. The print head 36 e is independently moved and positioned by a head moving mechanism different from the head moving mechanism described above, and the paper gap is set to an appropriate value.

  As described above, the print heads 36a to 36e, the UV lamps 37a and 37b, and the head moving mechanism are mounted on the unit frame to constitute the process unit 3U. Then, when performing the normal operation, that is, the printing process, as shown by a solid line in FIG. 1, it is positioned between the feeding unit 2 and the winding unit 4. On the other hand, when the maintenance operation of the process unit 3U, for example, the wiping process, capping process, etc., is performed on the print heads 36a to 36e, as shown by the one-dot chain line in FIG. Is moved to the maintenance unit 5 by the

  Returning to FIG. 2, the description of the configuration of the processing unit 3 and the winding unit 4 will be continued. In the processing unit 3, a UV lamp 38 is provided on the downstream side of the print head 36 e in the transport direction Ds. The UV lamp 38 completely cures (mainly cures) the transparent ink ejected by the print head 36 e by irradiating strong ultraviolet light. Thereby, the transparent ink can be fixed on the surface of the sheet S.

  The sheet S on which a color image is formed by the processing unit 3 is conveyed to the winding unit 4 by the rear drive roller 32. In addition to the winding shaft 40 around which the end of the sheet S is wound, the winding unit 4 includes a driven roller 41 that winds the sheet S from the back surface side between the winding shaft 40 and the rear drive roller 32. The winding shaft 40 winds up and supports the end of the sheet S with the surface of the sheet S facing outward. That is, when the take-up shaft 40 rotates clockwise on the sheet surface of FIG. 2, the sheet S conveyed from the rear drive roller 32 is taken up around the take-up shaft 40 via the driven roller 41. Incidentally, the sheet S is wound around the winding shaft 40 via a core tube (not shown) which is detachable from the winding shaft 40. Therefore, when the sheet S wound up by the winding shaft 40 becomes full, it is possible to remove the sheet S together with the core tube.

  Next, the configuration of the head moving mechanism (head moving mechanism for moving two print heads) provided in the process unit 3U will be described in detail with reference to FIGS.

  FIG. 3 is a perspective view of two print heads and a head moving mechanism for moving and positioning these print heads as viewed from the front side. 4 is an enlarged perspective view of a portion of the head moving mechanism shown in FIG. 3 as viewed from the rear side, and FIG. 5 is a view of the head moving mechanism shown in FIG. 3 as viewed from the rear side. . Further, FIG. 6 is a view for explaining the arrangement of the flat portion 63e of the right cam follower 63d of the head moving mechanism. In these drawings, only the head moving mechanism 6 for driving the print heads 36c and 36d is shown, and the illustration of the other configuration is omitted. In the following, the configuration and operation of the head moving mechanism 6 will be described with reference to these drawings, but since the head moving mechanism for moving the print heads 36a and 36b is also the same, the description of the configuration and operation is I omit it.

  The head moving mechanism 6 passes the landing position in the direction perpendicular to the tangent of the platen drum 30 at the position where printing is performed by the print head 36 c (the landing position of magenta ink) (that is, the pivoting axis 301 of the platen drum 30). (1), and the print head 36c is moved and positioned in the first direction D1. At the same time, a direction perpendicular to the tangent of the platen drum 30 at the position where printing is performed by the print head 36d (the impact position of the black ink) (that is, passing the impact position from the pivot shaft 301 of the platen drum 30) In the second embodiment, the printing head 36d is moved in the second direction D2 and positioned. As described above, in the present embodiment, the moving directions D1 and D2 of the print heads 36c and 36d are inclined to each other by the angle θ (see FIG. 5), and the head moving mechanism 6 maintains both the printings while maintaining the angular relationship. It has a function of moving and positioning the heads 36c and 36d.

  The head moving mechanism 6 has a holder 61c for holding the print head 36c. The holder 61 c has a front holder member 611, a rear holder member 612, and a connection plate 613 for connecting the two holder members 611 and 612, and the print head 36 c (an opening 614 provided in the rear holder member 612) It is insertable into and removable from the holder 61c from the -Y) direction.

  Linear guides 62 are extended in the first direction D1 on the front surface of the front holder member 611 and on the rear surface of the rear holder member 612, and the two linear guides 62 cause the holder 61c to face the front plate 35a and the back plate 35b. It is configured to be movable in the first direction D1. More specifically, as shown in FIG. 3, a linear rail 621 extending in the first direction D1 is fixed to the front surface of the front holder member 611 and two sliders 622 and 622 are provided along the rail 621. It is slidably mounted in the direction D1. And these two sliders 622 and 622 are being fixed to the rear surface of front plate 35a. Further, a linear guide 62 configured similarly to the front holder member 611 is attached also to the rear surface of the rear holder member 612, and the sliders 622, 622 of the linear guide 62 are fixed to the front surface of the rear plate 35b. Thus, by providing two linear guides 62, 62 in the front and rear direction in the holder 61c, the holder 61c is movable in the first direction D1 while holding the print head 36c.

  In the head moving mechanism 6, a holder 61d for holding the print head 36d is provided on the downstream side of the holder 61c at the downstream side in the transport direction Ds by a predetermined distance. Similar to the holder 61 c, the holder 61 d has a front holder member 611, a rear holder member 612 and a connection plate 613, and the print head 36 d is held against the holder 61 d through an opening 614 provided in the rear holder member 612. It has become removable.

  Further, linear guides 62 are extended in the second direction D 2 on the front surface of the front holder member 611 and on the rear surface of the rear holder member 612, and these two linear guides 62 extend to the front plate 35 a and the rear plate 35 b. The holder 61 d is configured to be movable in the second direction D2. The configuration of the linear guide 62 provided in the holder 61 d is the same as the linear guide 62 provided in the holder 61 c except that the extending direction of the rail 621 is different. Therefore, the same reference numerals are given here and the detailed description is omitted.

  One end (left end) of the left cam follower 63c is fixed to the front holder member 611 constituting the holder 61c, and the other end (right end) is directed rightward to the holder 61d, that is, in the (-X) direction It is extended to the side, and is extended to a substantially middle position of both front holder members 611. At the other end of the left cam follower 63c, as shown in FIG. 4, the rear side portion is slightly cut away and finished as a thin portion, and in the rear side direction of the thin portion, that is, in the (-Y) direction, A single bearing 64c is rotatably attached to the left cam follower 63c. The first bearing 64 c is in contact with a cam 65 described later, and its rotation axis is parallel to a cam shaft 66 which is a rotation axis of the cam 65. Further, a second bearing 64d as an interlocking member is rotatably attached to the other end of the first bearing 64c of the left cam follower 63c. The second bearing 64 d is in contact with a flat portion 63 e of a right side cam follower 63 d described later, and its rotation axis is parallel to a cam shaft 66 which is a rotation axis of the cam 65.

  One end (right end) of the right cam follower 63d is fixed to the front holder member 611 constituting the holder 61d, and the other end (left end) is directed leftward to the holder 61c, that is, the (X) direction side It is extended to the approximately middle position of both front holder members 611. The right cam follower 63d is configured to interlock with the left cam follower 63c via the second bearing 64d (interlocking member) attached to the left cam follower 63c, and is configured to be displaceable in the left-right direction with respect to the left cam follower 63c. ing. At the other end of the right cam follower 63d, a flat portion 63e in contact with the second bearing 64d is provided. The flat portion 63e realizes interlocking of the right cam follower 63d with the left cam follower 63c and displacement of the right cam follower 63d with respect to the left cam follower 63c.

  A cam 65 is rotatably disposed between the holders 61c and 61d. The cam 65 is disposed so as to contact the first bearing 64c attached to the left cam follower 63c and not to contact the second bearing 64d. The outer peripheral surface of the cam 65 abuts on the outer peripheral surface of the first bearing 64c, whereby the other end of the left cam follower 63c is supported. Further, the outer peripheral surface of the second bearing 64d attached to the left cam follower 63c abuts on the flat portion 63e of the right cam follower 63d, thereby supporting the other end of the right cam follower 63d. That is, the cam 65 indirectly supports the other end of the cam followers 63c and 63d.

  The cam 65 is finished to be slightly thicker than the thickness of the cam followers 63c and 63d, and is attached to a cam shaft 66 extended in the front-rear direction Y. The camshaft 66 is connected to an actuator 68 such as a motor via a power transmission unit 67, and the driving force generated by the actuator 68 is transmitted to the camshaft 66 by the power transmission unit 67. As a result, the cam shaft 66 pivots about the axis, and the cam 65 also pivots. By the rotation of the cam 65, the first bearing 64c in contact with the cam 65 is rotated and the left cam follower 63c is displaced with respect to the cam shaft 66, whereby the print head 36c is moved in the first direction D1. The right cam follower 63d interlocked with the left cam follower 63c via the two bearings 64d is displaced with respect to the cam shaft 66 and the left cam follower 63c, whereby the print head 36d is moved in the second direction D2.

  The outer peripheral surface of the cam 65 has a print adjustment area 651 for positioning the print nozzle at the print position by continuously changing the distance from the cam shaft 66 to the outer peripheral surface, as described in detail in the following operation description. Following the print adjustment area 651, there is a capping adjustment area 652 in which the distance from the cam shaft 66 to the outer peripheral surface is continuously changed to position the printing nozzle at the capping position. In the present embodiment, the distance from the cam shaft 66 to the outer peripheral surface changes in a mode corresponding to the printing process in the print adjustment area 651 as described later, while changes in a mode corresponding to the capping process in the capping adjustment area 652 And their aspects are different from one another. The capping adjustment area 652 includes a wiping adjustment area for positioning the printing nozzle at the wiping position.

  Here, the arrangement of the flat portion 63e of the right cam follower 63d will be described with reference to FIG.

  The virtual plane P1 including the flat portion 63e is orthogonal to the virtual plane P2 including a straight line bisecting an angle θ formed by a first straight line parallel to the first direction D1 and a second straight line parallel to the second direction D2. It is supposed to be. By doing this, the movement distance L1 of the left cam follower 63c (print head 36c) in the first direction D1 and the movement distance L2 of the right cam follower 63d (print head 36d) in the second direction D2 with the rotation of the cam 65 Can be identical. The reason why the moving distance L1 of the left cam follower 63c and the moving distance L2 of the right cam follower 63d become equal when the virtual plane P1 including the flat portion 63e is orthogonal to the virtual plane P2 will be described below with reference to FIG.

As shown in FIG. 6, assuming that the moving distance of the left cam follower 63c in the first direction D1 along with the rotation of the cam 65 is L1, the second bearing 64d moves in the first direction D1 in synchronization with the left cam follower 63c. The flat portion 63e of the right cam follower 63d is pushed by the moving distance L1 in the first direction D1 by the second bearing 64d. At this time, the right cam follower 63d is fixed to the holder 61d, and the moving direction of the holder 61d is restricted to the second direction D2 by the linear guide 62, so the right cam follower 63d does not move in the first direction D1. The movement distance along the guide 62 can be divided into a component in a direction parallel to the flat portion 63e and a component in a direction perpendicular to the flat portion 63e. Here, assuming that the angle formed by the direction perpendicular to the plane portion 63e and the first direction D1 is α, and the component in the direction perpendicular to the plane portion 63e of the movement distance L1 is L0, the relationship between L0 and L1 is as follows It is expressed by equation (1).
L0 = L1 · cos α (1)

When the moving distance of the right cam follower 63d in the second direction D2 is L2, the moving distance L2 is decomposed into a component in a direction parallel to the flat portion 63e and a component in a direction perpendicular to the flat portion 63e. The component in the direction perpendicular to the plane portion 63e is equal to the component L0 in the direction perpendicular to the plane portion 63e of the movement distance L1. Here, assuming that an angle formed by the direction perpendicular to the plane portion 63e and the second direction D2 is β, the following equation (2) holds, and the following equation (3) is derived from the equation (2).
cos β = L0 / L2 (2)
L0 = L2 · cos β (3)

From the equations (1) and (3), the following equation (4) representing the relationship between the movement distance L1 of the left cam follower 63c and the movement distance L2 of the right cam follower 63d is derived.
L2 = L1 · (cos α / cos β) (4)
From equation (4), it can be seen that “L2 = L1” when “α = β”. Since the sum of α and β is θ, L2 becomes equal to L1 by setting “α = β = θ / 2”. L0 can also be said to be a straight line dividing an angle θ formed by a first straight line (L1) parallel to the first direction D1 and a second straight line (L2) parallel to the second direction D2 into an angle α and an angle β Therefore, in the case of “α = β”, L0 is a straight line that bisects the angle θ formed by the first straight line and the second straight line, and is parallel to the virtual plane P2. Furthermore, since L0 is a component in a direction perpendicular to the flat portion 63e of the movement distance L1, it is perpendicular to the virtual plane P1. Therefore, when “L2 = L1”, it can be said that the virtual plane P1 and the virtual plane P2 are orthogonal, in other words, when the virtual plane P1 including the plane portion 63e is orthogonal to the virtual plane P2, the left cam follower 63c It can be said that the movement distance L1 is equal to the movement distance L2 of the right cam follower 63d.

  On the other hand, when the virtual plane P1 including the flat portion 63e is not orthogonal to the virtual plane P2, since α and β are different, L1 is necessarily different from L2. For example, in the case of α> β (however, 0 <α <90, 0 <β <90), cos α / cos β <1, and therefore L2 <L1. In this case, since L2 is smaller than L1, the moving distance of the right cam follower 63d is reduced more than the moving distance of the left cam follower 63c. Conversely, in the case of α <β, cos α / cos β> 1, and therefore L2> L1. In this case, since L2 is larger than L1, the moving distance of the right cam follower 63d is larger than the moving distance of the left cam follower 63c. In order to control the heights of the two heads 36c and 36d with the cam 65, if L1 and L2 are not the same amount, the cap position and the head height at the time of cleaning vary from head to head, making it difficult to control the position accuracy Become. Therefore, it is necessary to make L1 and L2 the same amount.

  Next, the operation of the head moving mechanism 6 configured as described above will be described in detail with reference to FIG.

  In the present embodiment, while the printing operation and the maintenance operation are not performed, as shown in FIG. 7A, one end of the print adjustment area 651 of the cam 65 (the position farthest from the capping adjustment area 652) is in the vertical direction. , And abut on a first bearing 64c attached to the left cam follower 63c. Further, in this state, the flat portion 63e of the right cam follower 63d abuts on the second bearing 64d attached to the left cam follower 63c. As a result, the print heads 36c and 36d are positioned at a position (home position) where the nozzle tips of the print heads 36c and 36d are separated from the platen drum 30 by a predetermined distance longer than the paper gap.

  When both ends of the sheet S are wound in a roll around the feeding unit 2 and the winding unit 4 and the printing process is performed in a stretched state between them, an operation command from the control unit is issued to the entire apparatus. Accordingly, the actuator 68 is actuated by an amount corresponding to the thickness of the sheet S, and the cam 65 is turned counterclockwise on the paper surface as shown in FIG. 7B, and the middle of the print adjustment area 651 of the cam 65 Position or the other end is positioned at the uppermost position in the vertical direction.

  In the present embodiment, the first bearing 64c is located above the cam 65 in the vertical direction, and is pressed against the cam 65 by the weight of the left cam follower 63c. Therefore, while the first bearing 64c abuts on the outer peripheral surface of the cam 65 and the first bearing 64c rotates with the rotation of the cam 65, the left cam follower 63c is displaced with respect to the cam shaft 66, The right cam follower 63d interlocked with the left cam follower 63c via the two bearings 64d is displaced with respect to the cam shaft 66 and the left cam follower 63c. As a result, the holder 61c connected to the left cam follower 63c descends in the first direction D1 and positions the print head 36c held by the holder 61c at the printing position according to the thickness of the sheet S. Thereby, the distance between the nozzle tip of the print head 36c and the sheet S is adjusted to a desired paper gap. Further, in parallel with the positioning of the print head 36c, the positioning of the print head 36d is performed. That is, the holder 61d connected to the cam follower 63d descends in the second direction D2 to position the print head 36d held by the holder 61d at the printing position, and the gap between the nozzle tip of the print head 36d and the sheet S is desired. Adjust to the paper gap. In the present embodiment, in the print adjustment area 651, since the distance from the cam shaft 66 to the outer peripheral surface continuously changes, by controlling the rotation angle of the cam 65, each print head 36c, 36d can be made with high accuracy. It can be positioned and the desired paper gap can be reliably obtained.

  The print heads 36a and 36b are also positioned by a head moving mechanism having the same configuration as the head moving mechanism 6 in the same manner as the print heads 36c and 36d. Further, the remaining print heads 36 e are positioned by another head moving mechanism.

  Thus, when the preparation for the printing operation is completed, the printing operation is performed, but it is necessary to perform the maintenance operation of the process unit 3U according to the operation status of the apparatus. In this maintenance operation, the process unit 3U is generally moved rearward, that is, in the (−Y) direction, and the maintenance unit 5 executes various maintenance processes. Among these maintenance processes, among those related to the print heads 36a to 36e, for example, there is a capping process, for example. This capping process is performed to prevent clogging of the nozzles of the print heads 36a to 36e, and the maintenance unit 5 executes the capping process as shown in FIGS. 7 (c) and 7 (d). A capping mechanism 51 is provided. Then, the capping process is performed on the process unit 3U moved to the maintenance unit 5 as follows.

  In the capping mechanism 51, cap portions 52 are fixedly disposed corresponding to the print heads 36a to 36e. Then, when the process unit 3U is moved to the capping mechanism 51, the print heads 36a to 36e are positioned vertically above the cap portions 52 provided correspondingly. Although only the print heads 36c and 36d are illustrated in FIG. 7 as in the printing operation, the other print heads are basically the same.

  When the positioning of the print heads 36c and 36d with respect to the cap portions 52 and 52 is completed, as shown in FIG. 7C, the actuator 68 operates in accordance with the operation command from the control unit, and the cam 65 is reversed in FIG. By rotating clockwise, the middle area (wiping adjustment area) of the capping adjustment area 652 of the cam 65 is positioned at the uppermost position in the vertical direction. While the first bearing 64c is rotated with the rotation of the cam 65 and the left cam follower 63c is displaced with respect to the cam shaft 66, the right cam follower 63d interlocked with the left cam follower 63c is the cam shaft 66 and the left cam follower 63c. As a result, the holders 61c and 61d connected by the cam followers 63c and 63d move in the first direction D1 and the second direction D2, respectively. As a result, the print heads 36 c and 36 d are positioned such that the nozzle tip approaches the cap 52. In this state, wiping processing of the print heads 36c and 36d can be performed using a wiper not shown.

  Subsequently, the actuator 68 is further operated in response to an operation command from the control unit, and as shown in FIG. 7D, the cam 65 is rotated counterclockwise in the drawing sheet surface to cap the cam 65. The final end of the adjustment area 652 is positioned at the uppermost position in the vertical direction. While the first bearing 64c is rotated with the rotation of the cam 65 and the left cam follower 63c is displaced with respect to the cam shaft 66, the right cam follower 63d interlocked with the left cam follower 63c is the cam shaft 66 and the left cam follower 63c. As a result, the holders 61c and 61d connected to the cam followers 63c and 63d move in the first direction D1 and the second direction D2, respectively. As a result, the print heads 36c and 36d are pressed against the cap portions 52 and 52, respectively, and the capping process is performed.

  When the capping process is completed, the actuator 68 is operated in the reverse direction according to the operation command from the control unit to raise the print heads 36c and 36d. Then, when various maintenance processes in the maintenance unit 5 are completed, the process unit 3U is returned to the original process unit 3.

  Thus, in the present embodiment, the platen drum 30 corresponds to the "roller" of the present invention. The print heads 36c and 36d respectively correspond to the "first print head" and the "second print head" of the present invention, and the holders 61c and 61d correspond to the "first holding portion" and the "second holding portion" of the present invention, respectively. Equivalent to The left cam follower 63c corresponds to the "first cam follower" of the present invention, and the right cam follower 63d corresponds to the "second cam follower" of the present invention.

  In the head moving mechanism 6 according to the embodiment described above, when the print head 36c is moved by displacing the left cam follower 63c by the rotation of the cam 65, the cam 65 can be brought into contact with the first bearing 64c. Further, when moving the print head 36d by displacing the right side cam follower 63d, the right side cam follower 63d can be interlocked with the left side cam follower 63c via the second bearing 64d. Therefore, direct contact between the cam 65 and the cam followers 63c and 63d can be prevented, so that wear of the cam 65 and the cam followers 63c and 63d can be suppressed.

  Further, in the head moving mechanism 6 according to the embodiment described above, the right cam follower 63d is a flat portion 63e that realizes interlocking of the right cam follower 63d to the left cam follower 63c and displacement of the right cam follower 63d to the left cam follower 63c. A virtual plane P2 including a straight line bisecting an angle θ formed by a first straight line parallel to the first direction D1 and a second straight line parallel to the second direction D2; Orthogonal to the Therefore, the movement distance L1 of the left cam follower 63c (print head 36c) and the movement distance L2 of the right cam follower 63d (print head 36d) in the first direction D1 along with the rotation of the cam 65 can be made the same.

  In the head moving mechanism 6 according to the embodiment described above, the second bearing 64d as the interlocking member attached to the left cam follower 63c is brought into contact with the flat portion 63e provided on the right cam follower 63d. The right cam follower 63d can be interlocked with the left cam follower 63c, and the right cam follower 63d can be displaced with respect to the left cam follower 63c.

  In the above embodiment, as shown in FIG. 4, the second bearing 64d is attached to the left cam follower (first cam follower) 63c and the flat portion 63e is provided on the right cam follower (second cam follower) 63d. As shown in FIG. 8, the second bearing 64d can be attached to the right cam follower (second cam follower) 63d, and the left cam follower (first cam follower) 63c can be provided with a flat portion 63e contacting the second bearing 64d. . Also in this case, a virtual plane including the flat portion 63e is a virtual plane including a straight line bisecting an angle θ formed by a first straight line parallel to the first direction D1 and a second straight line parallel to the second direction D2. Planar portions 63e are provided to be orthogonal to each other.

  In the above embodiment, the right cam follower 63d is interlocked with the left cam follower 63c via the second bearing 64d as an interlocking member, but instead of the second bearing 64d, a non-rotating protrusion is used. The left cam follower 63c (or the right cam follower 63d) may be provided as an interlocking member, and the right cam follower 63d may be interlocked with the left cam follower 63c through the projection. Furthermore, the right cam follower 63d may be brought into direct contact with the left cam follower 63c without providing such an interlocking member. For example, the left flat surface may be provided in the left cam follower 63c, and the right flat surface in contact with the left flat may be provided in the right cam follower 63d.

  Further, in the above embodiment, the head moving mechanism 6 drives two print heads simultaneously, but may be configured to simultaneously drive three or more print heads.

  In the above embodiment, the driving force generated by the actuator 68 is applied to the cam shaft 66 through the power transmission unit 67. However, the driving force is directly applied from the actuator 68 to the cam shaft 66. May be

  Furthermore, in the above embodiment, the present invention is applied to a head moving mechanism that drives a plurality of print heads that eject UV ink, but the specific configuration of the print head is not limited to this.

  The present invention is not limited to the above-described embodiments, and those skilled in the art with appropriate design modifications to such embodiments are also included in the scope of the present invention as long as they have the features of the present invention. . That is, each element with which the said embodiment is equipped, its arrangement | positioning, material, conditions, a shape, a size, etc. are not necessarily limited to what was illustrated, and can be changed suitably. Moreover, each element with which the said embodiment is equipped can be combined as much as technically possible, and what combined these is also included in the scope of the present invention as long as the feature of the present invention is included.

  DESCRIPTION OF SYMBOLS 1 ... printing apparatus, 6 ... head moving mechanism, 30 ... platen drum (roller), 36c ... printing head (1st printing head), 36d ... printing head (2nd printing head), 61c ... holder (1st holding part) 61 d Holder (second holding portion) 63 c Left cam follower (first cam follower) 63 d Right cam follower (second cam follower) 63 e Flat portion 64 c First bearing 64 d Second bearing (interlocking member , 65: cam, 66: cam shaft, 68: actuator, 301: rotation axis, D1: first direction, D2: second direction, P1 (including flat portion) virtual plane, P2: (first direction) A virtual plane including the straight line bisecting the angle formed by the first straight line parallel to the second straight line and the second straight line parallel to the second direction, S...

Claims (5)

A first holding unit that holds the first print head movably in a first direction; a second holding unit that holds the second print head movably in a second direction inclined with respect to the first direction; An actuator that generates a driving force for moving the first print head and the second print head, a cam that rotates about a cam shaft under the driving force of the actuator, and is attached to the first holding unit A head moving mechanism comprising: a first cam follower; and a second cam follower attached to the second holding portion, wherein
A first bearing in contact with the cam is attached to the first cam follower,
The second cam follower is configured to be in contact with the first cam follower or interlocked with the first cam follower through an interlocking member, and configured to be displaceable with respect to the first cam follower.
By the rotation of the cam,
The first bearing in contact with the cam rotates and the first cam follower is displaced with respect to the cam shaft, whereby the first print head moves in the first direction,
A head moving mechanism, wherein the second cam follower contacting or interlocking with the first cam follower is displaced with respect to the cam shaft and the first cam follower, thereby moving the second print head in the second direction. In at least one of the first cam follower and the second cam follower, a flat portion that realizes interlocking of the second cam follower with the first cam follower and displacement of the second cam follower with respect to the first cam follower Provided,
The virtual plane including the flat portion is orthogonal to a virtual plane including a straight line bisecting an angle formed by a first straight line parallel to the first direction and a second straight line parallel to the second direction. The head moving mechanism according to 1. A second bearing as the interlocking member is attached to one of the first cam follower and the second cam follower.
The head mechanism according to claim 2, wherein the other of the first cam follower and the second cam follower is provided with the flat portion in contact with the second bearing. A roller rotatably provided,
A first print head which discharges a first liquid from the first direction to a recording medium wound around the surface of the roller;
A second print head which discharges a second liquid from the second direction to a recording medium wound around the surface of the roller;
The head moving mechanism according to any one of claims 1 to 3, wherein the first print head is moved in the first direction, and the second print head is moved in the second direction;
A printing device comprising:   The printing apparatus according to claim 4, wherein the first direction and the second direction radially extend from a rotation axis of the roller.