JP2019166762A - Printer and driving method thereof - Google Patents

Abstract

To prevent deterioration of printing quality in printing start by eliminating a backlash generated by applying a force in an ascending direction to holders for supporting heads before the printing start.SOLUTION: A printer 1 includes: holders 61c and 61d which are liftable along a guide 62 extending in a prescribed direction; heads 36c and 36d which are supported by the holders 61c and 61d and perform printing on a recording medium S; a lifting section 68 which lifts the heads 36c and 36d through a cam 65; and a control section 69 which controls the lifting section 68. The control section 69 causes the lifting section 68 to perform reciprocating movement of the movement of the heads 36c and 36d in an ascending direction and the movement of the heads 36c and 36d in a descending direction a plurality of times after a work for applying a force in the ascending direction along the guide 62 to the holders 61c and 61d is executed and before printing by the heads 36c and 36d is started.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a printing apparatus and a driving method thereof.

  2. Description of the Related Art Conventionally, drum type printing apparatuses that record images by ejecting inks of different colors onto a recording medium from a plurality of print heads have been proposed. In such a drum-type printing apparatus, a recording medium is wound around a cylindrical platen drum in a state where tension is applied, and is supported by the surface of the platen drum. Each print head is configured to move in a direction perpendicular to the surface of the platen drum. In recent years, an elevating mechanism for elevating a print head using a cam in a drum-type printing apparatus has been proposed (see, for example, Patent Document 1).

JP 2013-226741 A

  In an elevating mechanism using a cam as described in Patent Document 1, if printing is performed immediately after an upward force is applied to a holder that supports the head by head cleaning or head replacement, etc. The inventors of the present invention have found that the print quality deteriorates only for a period of time.

  The cause of print quality deterioration is not clear, but ascending force is applied to the holder, so the position on the assembly between the holder and the head or between the holder and the lifting mechanism (cam, camshaft, guide, etc.) Even if the shift (backlash) occurs and the force in the upward direction is released and the original positional relationship is restored, the backlash is not eliminated, and the head position shifts, leading to deterioration in print quality. Inferred.

  The present invention has been made in view of such circumstances, and eliminates the play caused by the upward force applied to the holder that supports the head before the start of printing, thereby improving the print quality at the start of printing. The purpose is to prevent deterioration.

  In order to achieve the above object, a printing apparatus according to the present invention includes a holder that can be moved up and down along a guide extending in a predetermined direction, a head that is supported by the holder and performs printing on a recording medium, and a cam. And a control unit for controlling the lifting unit, the control unit is after the work to apply a force in the upward direction along the guide to the holder, Before the printing by the head is started, the reciprocating movement including the movement of the head in the upward direction and the movement of the head in the downward direction is performed by the elevating unit a plurality of times (for example, 20 times or more).

  The driving method according to the present invention includes a holder that can be lifted and lowered along a guide extending in a predetermined direction, a head that is supported by the holder and that prints on a recording medium, and a lift that lifts and lowers the head via a cam. And a control unit for controlling the lifting unit, and a printing method by the head is started after an operation of applying a force in the upward direction along the guide to the holder is performed. Before being performed, the control unit causes the elevating unit to perform reciprocating movement including movement of the head in the upward direction and movement of the head in the downward direction a plurality of times (for example, 20 times or more). Examples of the “operation” herein include an operation of removing the head from the holder, an operation of cleaning the head with a wiper, and an operation of capping the head with a cap member.

  When such a configuration and method are employed, the head is moved in the upward direction and the head after the operation of applying the upward force along the guide to the holder and before the printing by the head is started. The reciprocating movement consisting of the movement in the descending direction can be performed by the elevating part a plurality of times. Therefore, it is possible to eliminate the play caused by the upward force applied to the holder before starting printing. As a result, it is possible to prevent deterioration in print quality at the start of printing.

  The printing apparatus according to the present invention may include a notification unit that notifies the control unit of work information indicating that a work in which a force in the upward direction along the guide is applied to the holder is performed or has been performed. In such a case, the control unit, after the work information is notified from the notification unit, is performed after the work in which the upward force along the guide is applied to the holder and before the printing by the head is started. Until then, the reciprocating movement can be carried out a plurality of times.

  When such a configuration is adopted, when the work information indicating that the work in which the upward force along the guide is applied to the holder is performed (or performed) is notified, the reciprocation of the head is moved up and down. Can be performed multiple times.

  In the printing apparatus according to the present invention, the notification unit can notify the control unit of work information when the user performs a predetermined operation.

  When such a configuration is adopted, when the user performs a predetermined operation, the control unit displays work information indicating that a work in which an upward force along the guide is applied to the holder is performed (or has been performed). Can be notified.

FIG. 2 is a plan view showing the layout of the printing apparatus according to the embodiment of the present invention (viewed from above). 1 is a front view showing an overall configuration of a printing apparatus according to an embodiment of the present invention (viewed from the front side). FIG. 3 is a perspective view of the head movement mechanism of the printing apparatus according to the embodiment of the present invention as viewed from the front side. FIG. 3 is a partially enlarged perspective view when a part of the head moving mechanism of the printing apparatus according to the embodiment of the present invention is viewed from the rear side. FIG. 3 is a rear view of the head moving mechanism of the printing apparatus according to the embodiment of the present invention (viewed from the rear side). FIG. 5 is a diagram illustrating an operation of a head moving mechanism of the printing apparatus according to the embodiment of the invention. The figure which shows the state in which the force to the ascending direction was applied to the printing head (holder) of the printing apparatus which concerns on embodiment of this invention by wiping. The figure which shows the state by which the force to the ascending direction was applied to the printing head (holder) of the printing apparatus which concerns on embodiment of this invention by capping. The graph which shows the correlation with the frequency | count of the reciprocation of a print head, and positional offset amount, such as a print head.

  Hereinafter, a printing apparatus 1 according to an embodiment of the present invention will be described with reference to the drawings. In addition, this invention is not restrict | limited by this embodiment.

  FIG. 1 is a plan view showing a layout of the printing apparatus 1 according to the present embodiment. 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 device, and the maintenance unit 5 is disposed on the rear side of the process unit 3. 3U is movable with respect to the maintenance part 5 integrally. In these drawings and drawings to be described later, a three-dimensional coordinate system corresponding to the left-right direction X, the front-rear 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 feeding unit 2 and the winding unit 4 each have a feeding shaft 20 and a winding 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 feeding unit 2 to the process unit 3 along the route Pc thus stretched, subjected to a printing process by the process unit 3U, and then conveyed to the winding unit 4. The type of sheet S corresponding to the recording medium is roughly classified into a paper system and a film system. Specific examples include high-quality paper, cast paper, art paper, coated paper, and the like for paper, and synthetic paper, PET (Polyethylene terephthalate), PP (polypropylene), and the like for film. In the following description, of both surfaces of the sheet S, the surface on which an image is recorded is referred to as the front surface, and the opposite surface is referred to as the back surface.

  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 drawn from the feeding shaft 20 is wound. The feeding shaft 20 supports the end of the sheet S by winding the end thereof with the surface of the sheet S facing outward. Then, when the feeding shaft 20 rotates clockwise on the paper surface of FIG. 2, the sheet S wound around the feeding shaft 20 is fed to the process unit 3 via the driven roller 21. Incidentally, the sheet S is wound around the feeding shaft 20 via a core tube (not shown) that is detachable from the feeding shaft 20. Therefore, when the sheet S of the feeding shaft 20 is used up, a new core tube around which the roll-shaped sheet S is wound can be mounted on the feeding shaft 20 so that the sheet S of the feeding shaft 20 can be replaced. It has become. 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 process unit 3 appropriately performs processing by the process unit 3U disposed along the surface 30a of the platen drum 30 while supporting the sheet S fed from the feeding unit 2 on the surface 30a of the platen drum 30. The image is printed on. In the process unit 3, a front drive roller 31 and a 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. Receive the image.

  The front drive roller 31 has a plurality of minute protrusions formed by thermal spraying on the outer peripheral surface, and winds the sheet S fed from the feeding unit 2 from the back side. Then, the front driving roller 31 rotates clockwise on the paper surface of FIG. 2 to convey the sheet S fed from the feeding unit 2 to the downstream side of the conveying 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 while being biased toward the front drive roller 31, and sandwiches the sheet S between the front drive roller 31. Thereby, the frictional force between the front drive roller 31 and the sheet S is ensured, and the sheet S can be reliably conveyed by the front drive roller 31.

  The platen drum 30 is a cylindrical drum that is rotatably supported around a rotation 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 receives the frictional force between the sheet S and rotates in accordance with the conveying direction Ds of the sheet S, and supports the sheet S from the back surface side by the front surface 30a. Incidentally, the process unit 3 is provided with driven rollers 33 and 34 for folding the sheet S on both sides of the winding part around the platen drum 30. Among these, the driven roller 33 wraps the surface of the sheet S between the front driving roller 31 and the platen drum 30 and folds 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 the sheet S. In this way, by folding the sheet S on the upstream side and the downstream side in the transport direction Ds with respect to the platen drum 30, it is possible to secure a long winding portion of the sheet S around the platen drum 30.

  The rear drive roller 32 has a plurality of minute protrusions 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 back surface side. Then, the rear drive roller 32 conveys the sheet S to the winding unit 4 by rotating clockwise on the paper surface of FIG. A nip roller 32n is provided for the rear drive roller 32. The nip roller 32 n is in contact with the surface of the sheet S while being urged toward the rear drive roller 32, and sandwiches the sheet S between the rear drive roller 32. Thereby, the frictional force between the rear drive roller 32 and the sheet S is ensured, and the sheet S can be reliably conveyed by the rear drive roller 32.

  Thus, the sheet S conveyed from the front drive roller 31 to the rear drive roller 32 is supported by the surface 30 a of the platen drum 30. In the process unit 3, a process unit 3 </ b> 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 surface 30a of the platen drum 30, and is connected to each other by a connecting member (not shown) to form a unit frame. Then, the constituent elements of the process unit 3U (print heads 36a to 36e, UV lamps 37a and 37b, and a head moving mechanism) are mounted on 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 arranged radially from the rotation shaft 301 of the platen drum 30. The two print heads 36 a and 36 b arranged on the upstream side in the transport direction Ds among the print heads 36 a to 36 d are positioned with respect to the sheet S that is moved by one head moving mechanism and wound around the platen drum 30. Is done. Further, the two print heads 36 c and 36 d disposed on the downstream side are also moved by another head moving mechanism and positioned with respect to the sheet S wound around the platen drum 30. Then, by moving and positioning the four print heads 36a to 36d with these two head moving mechanisms, the distance between the nozzle tip (ink ejection port) of the print head 36a to 36d and the sheet S, It is possible to set a so-called paper gap to an appropriate value. As described above, the print heads 36a to 36d discharge ink onto the sheet S wound around the outer periphery of the platen drum 30 with the paper gap adjusted, thereby forming a color image on the surface of the sheet S. Is done. The configuration and operation of the head moving mechanism will be described in detail later.

  As the liquid such as ink and recording liquid used in the print heads 36a to 36d, UV (ultraviolet) ink (photo-curable ink) that is cured by irradiating ultraviolet rays (light) is used. Therefore, in the process unit 3U, UV lamps 37a and 37b are provided to cure the ink and fix it on the sheet S. The ink curing is performed in two stages, temporary curing and main curing. A temporary curing UV lamp 37a is arranged between each of the plurality of print heads 36a to 36d. That is, the UV lamp 37a irradiates relatively weak ultraviolet rays to cure (temporarily cure) the ink to such an extent that the shape of the ink does not collapse, and does not completely cure the ink. On the other hand, a UV lamp 37b for main curing is provided on the downstream side in the transport direction Ds with respect to the plurality of print heads 36a to 36d. In other words, the UV lamp 37b irradiates ultraviolet rays stronger than the UV lamp 37a, thereby completely curing (main curing) the ink. By performing the temporary curing and the main curing in this way, the color images formed by the plurality of print heads 36a to 36d can be fixed 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 36e is opposed to the surface of the sheet S wound around the platen drum 30 with a slight clearance, and discharges transparent UV ink onto the surface of the sheet S by an ink jet method. That is, the transparent ink is further ejected with respect to the color image formed by the print heads 36a to 36d for four colors. The print head 36e is moved and positioned independently 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. In the normal operation, that is, in performing the printing process, the positioning is performed between the feeding unit 2 and the winding unit 4 as indicated by a solid line in FIG. On the other hand, when performing maintenance operations of the process unit 3U, for example, wiping processing, capping processing, etc. for the print heads 36a to 36e, the process unit 3U is moved by a slide drive mechanism (not shown) as shown by a dashed line in FIG. It is moved to the maintenance unit 5.

  Returning to FIG. 2, the description of the configuration of the process unit 3 and the winding unit 4 will be continued. In the process unit 3, a UV lamp 38 is provided on the downstream side in the transport direction Ds with respect to the print head 36e. The UV lamp 38 is for completely curing (main curing) the transparent ink ejected by the print head 36e by irradiating with strong ultraviolet rays. Thereby, the transparent ink can be fixed on the surface of the sheet S. Since the configuration of the UV lamp 38 is substantially the same as the configuration of the UV lamp 37a, detailed description thereof will be omitted.

  The sheet S on which the color image is formed by the process unit 3 is conveyed to the winding unit 4 by the rear drive roller 32. The winding unit 4 includes a driven roller 41 that winds the sheet S from the back side between the winding shaft 40 and the rear drive roller 32 in addition to the winding shaft 40 around which the end of the sheet S is wound. The winding shaft 40 winds and supports the end of the sheet S with the surface of the sheet S facing outward. That is, when the winding shaft 40 rotates clockwise on the paper surface of FIG. 2, the sheet S conveyed from the rear drive roller 32 is wound around the winding shaft 40 via the driven roller 41. Incidentally, the sheet S is wound around the winding shaft 40 via a core tube (not shown) that is detachable from the winding shaft 40. Therefore, when the sheet S wound around 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 provided in the process unit 3U will be described in detail with reference to FIGS.

  FIG. 3 is a perspective view of a configuration of two print heads and a head moving mechanism that moves and positions these print heads when viewed from the front side. 4 is an enlarged perspective view when a part of the head moving mechanism shown in FIG. 3 is viewed from the rear side, and FIG. 5 is a view of the head moving mechanism shown in FIG. 3 viewed from the rear side. . In these drawings, only the head moving mechanism 6 that drives the print heads 36c and 36d is shown, and the other components are not shown. In the following, the configuration and operation of the head moving mechanism 6 will be described with reference to these drawings. However, since the head moving mechanism that moves the print heads 36a and 36b is the same, the description of the configuration and operation will be omitted. Omitted.

  The head moving mechanism 6 passes through the landing position from the rotation axis 301 of the platen drum 30 in a direction perpendicular to the tangent to the platen drum 30 at the position where printing is performed by the print head 36c (magenta ink landing position). The radial direction) is set as the first direction D1, and the print head 36c is moved in the first direction D1 for positioning. At the same time, a direction perpendicular to the tangent to the platen drum 30 at the position where printing is performed by the print head 36d (black ink landing position) (that is, passing through the landing position from the rotation shaft 301 of the platen drum 30). And the print head 36d is moved and positioned in the second direction D2. As described above, in this embodiment, the moving directions D1 and D2 of the two print heads 36c and 36d are inclined with respect to each other by the angle θ (see FIG. 5), and the head moving mechanism 6 performs both printing 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 that connects both the holder members 611 and 612, and the print head 36 c is connected to the print head 36 c through an opening 614 provided in the rear holder member 612 ( -Y) The holder 61c can be inserted and removed from the direction.

  Linear guides 62 extend in the first direction D1 on the front surface of the front holder member 611 and the rear surface of the rear holder member 612, and the holder 61c is attached to the front plate 35a and the back plate 35b by these two linear guides 62. 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 D <b> 1 is fixed to the front surface of the front holder member 611, and two sliders 622 and 622 are first along the rail 621. It is slidably attached in the direction D1. These two sliders 622 and 622 are fixed to the rear surface of the front plate 35a. Further, a linear guide 62 configured similarly to the front holder member 611 is attached to the rear surface of the rear holder member 612, and the sliders 622 and 622 of the linear guide 62 are fixed to the front surface of the back plate 35b. Thus, by providing the front and rear two linear guides 62, 62 on the holder 61c, the holder 61c can move 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 at a predetermined distance from the holder 61c on the downstream side in the transport direction Ds. Similar to the holder 61c, the holder 61d has a front holder member 611, a rear holder member 612, and a connecting plate 613. The print head 36d is connected to the holder 61d via an opening 614 provided in the rear holder member 612. Can be inserted and removed. Further, linear guides 62 extend in the second direction D2 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 are used for the front plate 35a and the back plate 35b. The holder 61d is configured to be movable in the second direction D2. The configuration of the linear guide 62 provided in the holder 61d is the same as that of the linear guide 62 provided in the holder 61c except that the extending direction of the rail 621 is different. For this reason, the same reference numerals are given here, and detailed descriptions thereof are omitted.

  One end portion (left end portion) of the left cam follower 63c is fixed to the front holder member 611 constituting the holder 61c, and the other end portion (right end portion) is directed to the holder 61d on the right side, that is, in the (−X) direction. It extends to the side, and extends to a substantially intermediate position between both front holder members 611. At the other end of the left cam follower 63c, as shown in FIG. 4, the rear portion is slightly cut off to be finished into a thin portion, and in the rear direction of the thin portion, that is, in the (−Y) direction, One bearing 64c is rotatably attached to the left cam follower 63c. The first bearing 64 c comes into contact with a cam 65 to be described later, and the rotation shaft thereof is parallel to the cam shaft 66 that is the rotation shaft of the cam 65. Further, a second bearing 64d is rotatably attached near the other end of the first bearing 64c of the left cam follower 63c. The second bearing 64d is in contact with a flat surface portion 63e of a right cam follower 63d described later, and its rotation axis is parallel to a cam shaft 66 (see FIG. 5) that 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 on the left side, that is, in the (+ X) direction side toward the holder 61c. And is extended to a substantially intermediate position between the front holder members 611. The right cam follower 63d is configured to interlock with the left cam follower 63c via a second bearing 64d 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. A flat surface portion 63e that contacts the second bearing 64d is provided at the other end of the right cam follower 63d. The flat surface 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, but not to the second bearing 64d. When the outer peripheral surface of the cam 65 contacts the outer peripheral surface of the first bearing 64c, the other end portion 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 contacts the flat surface portion 63e of the right cam follower 63d, whereby the other end of the right cam follower 63d is supported. That is, the cam 65 indirectly supports the other ends of the cam followers 63c and 63d.

  The cam 65 is finished to be slightly thicker than the cam followers 63c and 63d, and is attached to a cam shaft 66 (see FIG. 5) extending in the front-rear direction Y. The cam shaft 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 cam shaft 66 by the power transmission unit 67. As a result, the cam shaft 66 rotates about the axis and the cam 65 also rotates. As the cam 65 rotates, the first bearing 64c contacting the cam 65 rotates and the left cam follower 63c is displaced with respect to the cam shaft 66, whereby the print head 36c moves in the first direction D1, while the first 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, and thereby the print head 36d moves in the second direction D2.

  As will be described in detail in the following description of the operation, the outer peripheral surface of the cam 65 has a print adjustment area 651 (see FIG. 6) in which the distance from the cam shaft 66 to the outer peripheral surface continuously changes to position the print nozzle at the print position. ) And a capping adjustment area 652 (see FIG. 6) for continuously changing the distance from the cam shaft 66 to the outer peripheral surface to position the print nozzle at the capping position following the print adjustment area 651. . In the present embodiment, the distance from the cam shaft 66 to the outer peripheral surface changes in a manner corresponding to the printing process in the print adjustment area 651 as described later, whereas it changes in a manner corresponding to the capping process in the capping adjustment area 652. These aspects are different from each other. The capping adjustment area 652 includes a wiping adjustment area for positioning the print nozzle at the wiping position and a flushing adjustment area for performing a flushing process.

  As shown in FIGS. 7 and 8, the power transmission unit 67 includes a worm gear 67a connected to the actuator 68 and a wheel gear 67b having teeth that mesh with grooves provided in the worm gear 67a. The rotation shaft of the wheel gear 67 b is a cam shaft 66, and the wheel gear 67 b and the cam 65 rotate integrally around the cam shaft 66. The turning force of the actuator 68 is transmitted to the camshaft 66 via the worm gear 67a and the wheel gear 67b, whereby the camshaft 66 is rotated around the axis and the cam 65 is rotated.

  The actuator 68 is actuated by an operation command sent from the control unit 69 (see FIG. 3), and functions as a lifting unit in the present invention. The controller 69 controls the actuator 68 so that the amount of elevation of the print heads 36c and 36d can be adjusted. The control unit 69 has a CPU and a memory for storing various control programs and various data, and the CPU reads each control program and various data from the memory and executes them, whereby each component of the printing apparatus 1 is executed. Drive control is performed.

  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. 6A, one end of the print adjustment region 651 of the cam 65 (the position farthest from the capping adjustment region 652) is in the vertical direction. The first bearing 64c attached to the left cam follower 63c is in contact with the first cam follower 63c. In this state, the flat surface portion 63e of the right cam follower 63d contacts the second bearing 64d attached to the left cam follower 63c. As a result, the print heads 36c and 36d are positioned at the positions (home positions) 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 shape around the feeding unit 2 and the winding unit 4 and the printing process is performed in a state of being stretched between them, the entire apparatus is operated from the control unit 69. In response to the command, the actuator 68 is operated by an amount corresponding to the thickness of the sheet S, and the cam 65 is rotated counterclockwise on the paper surface as shown in FIG. The intermediate position or the other end is positioned at the uppermost position in the vertical direction.

  In the present embodiment, the first bearing 64c is positioned above the cam 65 in the vertical direction, and is pressed against the cam 65 by the weight of the left cam follower 63c. For this reason, the first bearing 64c abuts on the outer peripheral surface of the cam 65, the first bearing 64c rotates 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 displaced with respect to the cam shaft 66 and the left cam follower 63c via the two bearings 64d. 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 print position corresponding to the thickness of the sheet S. As a result, the distance between the nozzle tip of the print head 36c and the sheet S is adjusted to a desired paper gap. In parallel with the positioning of the print head 36c, the positioning of the print head 36d is executed. That is, the holder 61d connected to the cam follower 63d is lowered in the second direction D2 to position the print head 36d held by the holder 61d at the print position, and the interval between the nozzle tip of the print head 36d and the sheet S is set to a desired value. Adjust to paper gap. In the present embodiment, since the distance from the cam shaft 66 to the outer peripheral surface continuously changes in the print adjustment area 651, the print heads 36c and 36d are controlled with high accuracy by controlling the rotation angle of the cam 65. It can position and can obtain a desired paper gap reliably.

  The print heads 36a and 36b are also positioned by the 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 head 36e is positioned by another head moving mechanism.

  Thus, when the preparation for the printing operation is completed, the printing operation is executed, 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 entirely moved in the rear side, that is, in the (−Y) direction, and various maintenance processes are executed in the maintenance unit 5. Among these maintenance processes, a process related to the print heads 36a to 36e is, for example, a capping process. 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. 6 (c) and 6 (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.

  The capping mechanism 51 has a cap member 52 that is fixedly disposed corresponding to each of 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 above the cap members 52 provided in correspondence with each other. In FIG. 6, only the print heads 36c and 36d are illustrated as in the printing operation, but the other print heads are basically the same.

  When the positioning of the print heads 36c and 36d with respect to the cap members 52 and 52 is completed, as shown in FIG. 6C, the actuator 68 is operated in accordance with an operation command from the control unit 69, and the cam 65 is By rotating counterclockwise, an intermediate area (wiping adjustment area) of the capping adjustment area 652 of the cam 65 is positioned at the uppermost position in the vertical direction. As the cam 65 rotates, the first bearing 64c rotates and the left cam follower 63c displaces with respect to the cam shaft 66, while the right cam follower 63d interlocked with the left cam follower 63c includes 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 so that the nozzle tip is close to the cap member 52. In this state, the wiping process of the print heads 36c and 36d can be performed using the wiper 70 (see FIG. 7).

  Following this, the actuator 68 is further actuated in accordance with an operation command from the control unit 69, and as shown in FIG. 6D, the cam 65 is rotated counterclockwise on the paper surface of FIG. The final end of the capping adjustment area 652 is positioned at the uppermost position in the vertical direction. As the cam 65 rotates, the first bearing 64c rotates and the left cam follower 63c displaces with respect to the cam shaft 66, while the right cam follower 63d interlocked with the left cam follower 63c includes 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 members 52 and 52, respectively, and the capping process is executed.

  When the capping process is completed, the actuator 68 operates in the reverse direction in accordance with an operation command from the control unit 69 to raise the print heads 36c and 36d. When various maintenance processes in the maintenance unit 5 are completed, the process unit 3U is returned to the original process unit 3.

  Next, misregistration elimination control by the control unit 69 of the printing apparatus 1 according to the present embodiment will be described.

  As shown in FIG. 3, the holder 61c holds the print head 36c, and the holder 61d holds the print head 36d. However, when the user removes the print heads 36c, 36d from the holders 61c, 61d, the holder 61c, A force in the upward direction along the linear guide 62 is applied to 61d. 7, the nozzle surfaces of the print heads 36c and 36d are cleaned with the wiper 70, or the nozzle surfaces of the print heads 36c and 36d are capped with the cap member 52 as shown in FIG. Similarly, when the work is performed, a force in the upward direction along the linear guide 62 is applied to the holders 61c and 61d.

  As described above, when printing is performed immediately after the force in the upward direction is applied to the holders 61c and 61d, it is clear that the print quality deteriorates only for a predetermined period from the restart of printing. The cause of the deterioration of the print quality is not clear, but when an upward force is applied to the holders 61c and 61d, the holders 61c and 61d and the print heads 36c and 36d, or between the holders 61c and 61d and the head moving mechanism 6 ( Ascending position misalignment (backlash) occurs between the cam 65, the cam shaft 66, the linear guide 62, etc., or the bending of the cam shaft 66 is temporarily reduced, so that the upward force is released. Even after returning to the original positional relationship, the backlash or the like is not eliminated, so that the positions of the print heads 36c and 36d are shifted, and it is assumed that the print quality is deteriorated.

  The control unit 69 in the present embodiment performs control for eliminating such misalignment. Specifically, the control unit 69 performs the operation after applying the force in the upward direction along the linear guide 62 to the holders 61c and 61d and before the printing by the print heads 36c and 36d is started. In addition, the actuator 68 is caused to perform a reciprocating motion including the movement of the print heads 36c and 36d in the upward direction and the movement of the print heads 36c and 36d in the downward direction a plurality of times.

  In the printing apparatus 1 according to the present embodiment, the control unit 69 includes work information indicating that work for applying a force in the upward direction along the linear guide 62 to the holders 61c and 61d is performed (or has been performed). A notification unit 69a (see FIG. 3) for notifying is provided. The notification unit 69a is configured to notify the control unit 69 of the already-described work information when a user performs a predetermined operation using an operation unit (not shown). When the operation information is notified from the notification unit 69a, the control unit 69 performs the operation of applying a force in the upward direction along the linear guide 62 to the holders 61c and 61d and the print heads 36c and 36d. Before the start of printing according to, the actuator 68 is caused to reciprocate the print heads 36c and 36d a plurality of times (for example, 20 times or more).

  In the present embodiment, a configuration is adopted in which the notification unit 69a notifies the control unit 69 of work information when a user performs a predetermined operation on the operation unit, but instead of providing an operation unit, A sensor is provided to detect that an operation in which an upward force is applied to the holders 61c and 61d, and the notification unit 69a notifies the control unit 69 of the work information when the sensor detects the execution of the operation. Such a configuration may be adopted.

  FIG. 9 is a graph showing the correlation between the number of times the print head reciprocates and the amount of positional deviation of the print head or the like. The misregistration amount “0 (μm)” represents the position of the print head or the like when assuming a state immediately after the print head is removed from the holder and then the print head is returned to the holder. The “minus” value of means that the position of the print head or the like has changed in the downward direction. Here, the amount of positional deviation of the print head or the like was measured by three types of measurement methods A, B, and C. Measurement method A is a method of measuring the amount of displacement at the origin (the position of the cam surface when the print head is moved to the most upward direction along the linear guide) in a digimatic manner. This is a method of measuring the amount of displacement in the shaft with an insulator-type dial gauge, and measurement method C is a method of measuring the amount of displacement in the print position of the print head in a digimatic manner.

  As is clear from FIG. 9, immediately after the force in the upward direction is applied to the holder (that is, when the print head reciprocates “0” times), even if the print head is attached to the holder, The amount of deviation is substantially “0” μm (that is, the same state as when the print head is removed from the holder). If the reciprocation of the print head is repeated from this state, the position of the print head, etc., suddenly changes in the downward direction (minus displacement), but the change in the downward direction of the position is about 20 reciprocations. After that, it becomes clear that the amount of positional deviation does not change so much, especially after 100 times. For this reason, it is preferable that the reciprocation of the print head is performed “20 times or more” after the operation in which the force in the upward direction is applied to the holder and before the printing by the print head is started. In addition, although the upper limit of the frequency | count of a reciprocating movement is not specifically limited, when efficiency etc. are considered, it is desirable to set it as less than 100 times.

  In the printing apparatus 1 according to the embodiment described above, printing by the print heads 36c and 36d is started after an operation in which a force in the upward direction along the linear guide 62 is applied to the holders 61c and 61d. The controller 69 can cause the actuator 68 to reciprocate the print heads 36c and 36d a plurality of times before the operation is completed. Therefore, it is possible to eliminate the play caused by the upward force applied to the holders 61c and 61d before starting printing. As a result, it is possible to prevent deterioration in print quality at the start of printing.

  Further, in the printing apparatus 1 according to the embodiment described above, when the user performs a predetermined operation, an operation in which a force in the upward direction along the linear guide 62 is applied to the holders 61c and 61d is performed. The work information indicating (or has been implemented) can be notified from the notification unit 69a to the control unit 69. Then, the control unit 69 that has received the notification of the work information can cause the actuator 68 to reciprocate the print heads 36c and 36d a plurality of times.

  The present invention is not limited to the above-described embodiments, and those in which those skilled in the art appropriately modify the design are included in the scope of the present invention as long as they have the features of the present invention. . In other words, each element included in the embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed. Moreover, each element with which this embodiment is provided can be combined as long as it is technically possible, and the combination thereof is also included in the scope of the present invention as long as it includes the features of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Printing apparatus, 36c * 36d ... Print head, 52 ... Cap member, 61c * 61d ... Holder, 62 ... Linear guide, 65 ... Cam, 68 ... Actuator (elevating part), 69 ... Control part, 69a ... Notification part, 70 ... Wiper, S ... Sheet (Recording medium)

Claims (8)

A holder that can be moved up and down along a guide extending in a predetermined direction, a head that is supported by the holder and that prints on a recording medium, a lifting unit that lifts and lowers the head via a cam, and controls the lifting unit A printing device comprising a control unit,
The control unit is configured to move the head in the ascending direction after an operation of applying a force in the ascending direction along the guide to the holder and before printing by the head is started. A printing apparatus that causes the elevating unit to perform a reciprocating movement including a downward movement of the head a plurality of times. A work is performed to apply a force in the ascending direction along the guide to the holder, or a notification unit that notifies the control unit of work information indicating that work has been performed,
When the operation information is notified from the notification unit, the control unit is configured to start printing by the head after an operation in which an upward force along the guide is applied to the holder is performed. The printing apparatus according to claim 1, wherein the reciprocating movement is performed a plurality of times before printing.   The printing apparatus according to claim 2, wherein the notification unit notifies the control unit of the work information when a user performs a predetermined operation.   The printing apparatus according to claim 1, wherein the work is a work of removing the head from the holder.   The printing apparatus according to claim 1, wherein the work is a work of cleaning the head with a wiper.   The printing apparatus according to claim 1, wherein the operation is an operation of capping the head with a cap member.   The printing apparatus according to claim 1, wherein the control unit causes the elevating unit to perform the reciprocating movement 20 times or more. A holder that can be moved up and down along a guide extending in a predetermined direction, a head that is supported by the holder and that prints on a recording medium, a lifting unit that lifts and lowers the head via a cam, and controls the lifting unit And a control unit for driving a printing apparatus comprising:
After the operation of applying a force in the upward direction along the guide to the holder is performed and before the printing by the head is started, the control unit moves the head in the upward direction. A method for driving a printing apparatus, wherein the elevating unit performs a reciprocating movement including a movement of the head in a downward direction a plurality of times.

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