JP2019155861A - Printing device - Google Patents

Abstract

To provide a printing device, which can suppress deterioration in printing quality and the like by accurately controlling a position of a head of the device.SOLUTION: A printing device 1 is provided with a head 63c that can be lifted up and down along a guide 62 extending in a predetermined direction, a lifting-up/down part 68 that lifts up and down the head 63c through a cam 65 and a control part 69 that controls the lifting-up/down part 68 so that lifting quantities of the head 63c are adjusted. The control part 69 controls the lifting-up/down part 68 so that the lifting quantities of the head 63c are adjusted in a first lifting-up/down section in a lifting-up/down range of the head 63c, using a first non-linear approximation formula for approximating a relation between turning quantities of the cam 65 and the lifting quantities of the head 63c, and so that the lifting quantities of the head 63c are adjusted in a second lifting-up/down section in the lifting-up/down range of the head 63c, using a second non-linear approximation formula for approximating a relation between the turning quantities of the cam 65 and the lifting quantities of the head 63c. The second non-linear approximation formula is different from the first non-linear approximation formula.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a printing apparatus.

  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, a mechanism has been proposed in which a print head is moved up and down using a cam in a drum-type printing apparatus (see, for example, Patent Document 1). In such a mechanism using a cam, the distance from the cam shaft to the outer peripheral surface of the cam changes depending on the phase (cam rotation angle), so the print head moves “non-linearly”. Conventionally, in order to control such “non-linear” movement, an approximate expression in which the movement of the print head is linearly complemented has been used.

JP 2013-226741 A

  However, there is a problem that the difference between the conventional linearly-complemented approximate expression and the actual lifting curve is large, and the print head position cannot be controlled with high accuracy. When the accuracy of the print head position in the print area is deteriorated, not only the print quality is deteriorated, but also the print head may come into contact with the paper to damage the printed matter or damage the print head. Further, when the accuracy of the print head position in the maintenance area is deteriorated, a print head maintenance failure may occur.

  The present invention has been made in view of such circumstances, and an object of the present invention is to suppress a decrease in print quality and the like by more accurately controlling the position of the head of a printing apparatus.

  In order to achieve the above object, an apparatus according to the present invention includes a member movable along a predetermined direction, a moving unit that moves the member via a cam, and a moving amount of the member by controlling the moving unit. A control unit that adjusts the relationship between the cam rotation amount and the member movement amount in the first movement section in the member movement range by controlling the movement unit. Is adjusted using the first non-linear approximation formula that approximates, while the second movement section approximates the relationship between the cam rotation amount and the member movement amount in the second movement section of the member movement range. The amount of movement of the member is adjusted using a nonlinear approximation formula. Here, the second nonlinear approximation expression is different from the first nonlinear approximation expression.

  When such a configuration is adopted, the movement range of the member is divided into two sections (first movement section and second movement section), and different nonlinear approximation expressions (first nonlinear approximation expression and second nonlinear approximation expression) that are different in each movement section. It is possible to adjust the amount of movement of the member. Therefore, the position of the member can be controlled with high accuracy.

  In the apparatus according to the present invention, the movement amount of the member in the second movement section is made larger than the movement amount of the member in the first movement section, and the order of the second nonlinear approximation expression is set higher than the order of the first nonlinear approximation expression. Can be bigger.

  In the apparatus according to the present invention, the first movement section is made closer to the origin position of the movement range of the member than the second movement section, and the order of the second nonlinear approximation expression is made larger than the order of the first nonlinear approximation expression. be able to.

  In the apparatus according to the present invention, the cam may have a first gradient corresponding to the first movement section and a second gradient corresponding to the second movement section. In such a case, the second gradient can be made larger than the first gradient, and the order of the second nonlinear approximation formula can be made larger than the order of the first nonlinear approximation formula. The “gradient” refers to the rate at which the distance from the cam shaft to the cam outer peripheral surface changes depending on the phase (cam rotation angle).

  The printing apparatus according to the present invention includes a head that can be moved up and down along a guide extending in a predetermined direction, a lifting unit that lifts and lowers the head via a cam, and a lifting amount of the head by controlling the lifting unit. A control unit that adjusts the amount of rotation of the cam and the amount of elevation of the head in the first elevation section in the elevation range of the head by controlling the elevation unit. While adjusting the head lift using the first nonlinear approximation formula that approximates the relationship, the second approximation section in the head lift range approximates the relationship between the cam rotation and the head lift. (2) The head lift is adjusted using a nonlinear approximation formula. Here, the second nonlinear approximation expression is different from the first nonlinear approximation expression.

  When such a configuration is adopted, the head lifting range is divided into two sections (first lifting section and second lifting section), and different nonlinear approximation formulas (first nonlinear approximation formula and second nonlinear approximation formula) that are different in each lifting section. It is possible to adjust the lifting / lowering amount of the head. Therefore, the position of the head can be controlled with high accuracy.

  In the printing apparatus according to the present invention, the head lifting amount in the second lifting section is set to be larger than the head lifting amount in the first lifting section, and the order of the second nonlinear approximation formula is determined from the order of the first nonlinear approximation formula. Can also be increased.

  In the printing apparatus according to the present invention, the first lifting section is closer to the origin position of the head lifting range than the second lifting section, and the order of the second nonlinear approximation formula is larger than the order of the first nonlinear approximation formula. can do.

  In the printing apparatus according to the present invention, the cam may have a first slope corresponding to the first lifting section and a second slope corresponding to the second lifting section. In such a case, the second gradient can be made larger than the first gradient, and the order of the second nonlinear approximation formula can be made larger than the order of the first nonlinear approximation formula.

  In the printing apparatus according to the present invention, the first elevating section may include a print area of the head, and the second elevating section may include a head maintenance area.

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). The figure for demonstrating the structure of the cam of the printing apparatus which concerns on embodiment of this invention. FIG. 4 is a diagram illustrating a relationship between a movement amount of a print head and a rotation amount of a cam in the entire lift range of the print head of the printing apparatus according to the embodiment of the present invention. FIG. 4 is a diagram illustrating a relationship between a movement amount of a print head and a rotation amount of a cam in a printing region of a printing apparatus according to an embodiment of the present invention. FIG. 4 is a diagram illustrating a relationship between a print head movement amount and a cam rotation amount in a maintenance area of the printing apparatus according to the embodiment of the present invention. FIG. 5 is a diagram illustrating an operation of the head moving mechanism according to the embodiment of the invention.

  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. The actuator 68 is actuated by an operation command sent from the control unit 69 (see FIG. 3), and functions as a lifting unit (moving 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.

  Here, the elevation control of the print head 36c of the printing apparatus 1 according to the present embodiment will be described with reference to FIGS.

FIG. 6 is a diagram for explaining the configuration of the cam 65 of the printing apparatus 1. FIG. 7 is a diagram showing the relationship between the amount of movement of the print head 36c and the amount of rotation of the cam 65 in the entire lifting range of the print head 36c, and FIG. 8 shows the relationship between the print head 36c in the print area A ₁ (described later). FIG. 9 is a diagram showing the relationship between the amount of movement of the print head 36 c and the amount of rotation of the cam 65 in the maintenance area A ₂ (described later). . In the following description, only the elevation control of the print head 36c will be described, and the elevation control of the other print heads is substantially the same as the elevation control of the print head 36c, and thus detailed description thereof will be omitted. . The print head 36c corresponds to a “member (head)” in the present invention.

As shown in FIG. 6, the cam 65 is configured such that the distance from the cam shaft 66 to the outer peripheral surface thereof continuously changes. The outer surface of the cam 65 has a first area 651 corresponding to the print area A ₁ (see FIG. 7) of the print head 36c, and a second area 652 corresponding to the maintenance area A ₂ (see FIG. 7) of the print head 36c. ,have.

Printing area A ₁ is a elevation section performs print processing of all the lifting range of the print head 36c (total travel), corresponding to the first lifting section in the present invention (first movement section). As the first region 651 of the cam 65 corresponding to the print area A _1, for example, as shown in FIG. 6, a phase (rotational angle of the cam 65) can be employed following areas 70 ° 58 ° or more.

Maintenance area A ₂ is a elevation section that performs maintenance processing of all lifting range of the print head 36c, corresponding to the second elevating section in the present invention (second movement section). The second region 652 of the cam 65 corresponding to the maintenance area A _2, for example, as shown in FIG. 6, the phase can be adopted the following regions 202 ° 110 ° or more. Maintenance area A _2, the position of a wiping process, the position for capping process, and a region for the flushing process.

As shown in FIG. 6, the gradient (second gradient) in the second region 652 of the cam 65 is set to be larger than the gradient (first gradient) in the first region 651, as shown in FIG. In addition, the elevation amount of the print head 36c in the maintenance area A ₂ (second elevation section) is set to be larger than the elevation ratio of the print head 36c in the print area A ₁ (first elevation section). As shown in FIGS. 6 and 7, the printing area A ₁ (first elevating section) is located at the origin position (phase 0) of the entire elevating range of the print head 36 c than the maintenance area A ₂ (second elevating section). Set near (°). In the present invention, the “gradient” (of the cam) means the rate at which the distance from the cam shaft 66 to the outer peripheral surface of the cam 65 changes depending on the phase.

Control unit 69, by controlling the actuator 68, in the printing area A _1, the lifting of the print heads 36c with a first non-linear approximation equation that approximates the relationship between the lift amount of the print head 36c rotation of the cam 65 while adjusting the amount, in the maintenance area a _2, to adjust the amount of vertical movement of the print heads 36c with a second non-linear approximation equation that approximates the relationship between the lift amount of the print head 36c rotation of the cam. In the present embodiment, a “fourth order” nonlinear approximation formula is adopted as the first nonlinear approximation formula, and a “sixth order” nonlinear approximation formula is adopted as the second nonlinear approximation formula. The first nonlinear approximation formula and the second nonlinear approximation formula are stored in the memory (storage unit) of the control unit 69, and are used for the elevation control of the print head 36c.

Graph of Figure 8, in the printing area A _1, the moving amount from the origin of the print head 36c (mm) of setting the horizontal axis X, is obtained by setting the amount of rotation of the cam 65 (°) to the vertical axis Y . Control unit 69 in the present embodiment, in the printing area A _1, performs elevation control of the print heads 36c employs a non-linear approximation equation (1) "Quaternary" as follows.
Y = a ₁ X ⁴ + b ₁ X ³ + c ₁ X ² + d ₁ X + e ₁ (1)
The coefficients a ₁ , b ₁ , c ₁ , d ₁ , and e ₁ in Expression (1) can be set as appropriate according to the specifications of the printing apparatus 1, the type of the sheet S, and the like. When the target value of the movement amount of the print head 36c is input, the control unit 69 calculates the rotation amount of the cam 65 corresponding to the target value using the equation (1), and the calculated rotation amount. The actuator 68 is controlled so that the cam 65 is rotated.

Graph of Figure 9, in the maintenance area A _2, the moving amount from the origin of the print head 36c (mm) of setting the horizontal axis X, is obtained by setting the amount of rotation of the cam 65 (°) to the vertical axis Y . Control unit 69 in the present embodiment, in the maintenance area A _2, performs elevation control of the print heads 36c employs a non-linear approximation equation (2) of the "next six" as follows.
Y = a ₂ X ⁶ + b ₂ X ⁵ + c ₂ X ⁴ + d ₂ X ³ + e ₂ X ² + f ₂ X + g ₂ (2)
Coefficients a ₂ , b ₂ , c ₂ , d ₂ , e ₂ , f ₂ , and g ₂ in Expression (2) can be appropriately set according to the specifications of the printing apparatus 1, the type of the sheet S, and the like. When a target value for the amount of movement of the print head 36c is input, the control unit 69 calculates the amount of rotation of the cam 65 corresponding to the target value using Equation (2), and the calculated amount of rotation. The actuator 68 is controlled so that the cam 65 is rotated.

  Next, the operation of the head moving mechanism 6 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. 10A, the origin position of the cam 65 (position of phase 0 °: see FIG. 6) is positioned at the uppermost position in the vertical direction. Then, it comes into contact with the first bearing 64c attached to the left 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 executed in a state of being stretched between them, the operation command from the control unit 69 is changed. Then, the actuator 68 is operated by an amount corresponding to the thickness of the sheet S, and as shown in FIG. 10B, the cam 65 is rotated counterclockwise on the paper surface, and an appropriate position (for example, the first region 651 of the cam 65 (for example, The printing reference position of phase 67 ° (see FIG. 6) 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 the first bearing 64c 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, in the first region 651, the control unit 69 can position the print heads 36c and 36d with high accuracy by controlling the rotation amount of the cam 65 using the above-described equation (1). A desired paper gap can be obtained 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. 10 (c) and 10 (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, a cap portion 52 is fixedly disposed corresponding to each of the print heads 36a to 36e. When the process unit 3U is moved to the capping mechanism 51, the print heads 36a to 36e are positioned above the cap portion 52 provided corresponding to each of the print heads 36a to 36e. In FIG. 10, only the print heads 36 c and 36 d 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 portions 52 and 52 is completed, as shown in FIG. 10 (c), the actuator 68 is operated in accordance with an operation command from the control portion 69, and the cam 65 is The position for wiping in the second area 652 of the cam 65 is positioned at the uppermost position in the vertical direction by rotating counterclockwise. 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 moves to 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 36c and 36d move so that the tip of the nozzle approaches the cap portion 52, and are positioned at a height that allows wiping. In this state, the wiping process of the print heads 36c and 36d can be performed using a wiper (not shown).

  Next, the actuator 68 is further actuated in accordance with an operation command from the control unit 69, and the cam 65 is rotated counterclockwise on the paper surface of the drawing, so that the flushing region in the second region 652 of the cam 65 is vertically adjusted. Position at the top of the 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 moves to 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 closer to the cap portion 52. In this state, the flushing process of the print heads 36c and 36d can be performed.

  Following this, the actuator 68 further operates in accordance with an operation command from the control unit 69, and as shown in FIG. 10 (d), the cam 65 is rotated counterclockwise on the paper surface of FIG. The position for capping processing in the second region 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 moves to 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 executed. In the present embodiment, in the second region 652, the control unit 69 can position the print heads 36c and 36d with high accuracy by controlling the rotation amount of the cam 65 using the above-described equation (2).

  Thereafter, 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.

In the printing apparatus 1 according to the embodiment described above, divided lifting range of the print head 36c into two sections (printing area A ₁ and a maintenance area A _2), different nonlinear approximate expression (first nonlinear approximation in the lifting section The lift amount of the print head 36c can be adjusted using the formula (1) and the second nonlinear approximation formula (2). Therefore, the position of the print head 36c can be controlled with high accuracy.

  In the present embodiment, an example is shown in which the “fourth order expression” is adopted as the first nonlinear approximation expression and the “sixth order expression” is adopted as the second nonlinear approximation expression. The two nonlinear approximation equations are not limited to these, and it is sufficient that the two are different. However, the order of the nonlinear approximation formula used in a section where the print head lift (cam slope) is large is larger than the order of the nonlinear approximation formula used in a section where the print head lift (cam slope) is small. Try to set it larger.

  In this embodiment, an example in which the present invention is applied to a “printing apparatus” has been described. However, the present invention can also be applied to an apparatus different from the printing apparatus. That is, an apparatus (printing apparatus) that includes a member that can move along a predetermined direction, a moving unit that moves the member via a cam, and a control unit that adjusts the amount of movement of the member by controlling the moving unit. In the first apparatus, the control unit controls the moving unit to adjust the moving amount of the member using the first nonlinear approximation expression in the first moving section in the moving range of the member, while moving the member. The movement amount of the member can be adjusted using the second nonlinear approximation formula (different from the first nonlinear approximation formula) in the second movement section in the range.

  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.

1 ... printing apparatus (device), 36c ... print head (member, the head), 62 ... linear guide (guide) 65 ... cam, 68 ... actuator (mobile unit, the lifting unit), 69 ... control unit, A 1 _... Print Area (first movement section, first lifting section), A ₂ ... maintenance area (second movement section, second lifting section)

Claims (9)

An apparatus comprising: a member movable along a predetermined direction; a moving unit that moves the member via a cam; and a control unit that adjusts the amount of movement of the member by controlling the moving unit. And
The control unit controls the moving unit, and thereby a first nonlinear approximation formula that approximates a relationship between a rotation amount of the cam and a movement amount of the member in a first movement section in a movement range of the member. Is used to adjust the movement amount of the member, and in the second movement section in the movement range of the member, a second nonlinear approximation formula that approximates the relationship between the rotation amount of the cam and the movement amount of the member. Use to adjust the amount of movement of the member,
The second nonlinear approximation formula is different from the first nonlinear approximation formula. The movement amount of the member in the second movement section is larger than the movement amount of the member in the first movement section,
The apparatus according to claim 1, wherein the order of the second nonlinear approximate expression is greater than the order of the first nonlinear approximate expression. The first movement section is closer to the origin position of the movement range of the member than the second movement section,
The apparatus according to claim 1, wherein the order of the second nonlinear approximation expression is larger than the order of the first nonlinear approximation expression. The cam has a first gradient corresponding to the first movement section, and a second gradient corresponding to the second movement section,
The second gradient is greater than the first gradient;
4. The apparatus according to claim 1, wherein the order of the second nonlinear approximation formula is larger than the order of the first nonlinear approximation formula. 5. A head that can be moved up and down along a guide extending in a predetermined direction, a lift unit that lifts and lowers the head via a cam, and a control unit that adjusts the lift amount of the head by controlling the lift unit; A printing apparatus comprising:
The control unit controls the elevating unit to control a first nonlinear approximation formula that approximates a relationship between the cam rotation amount and the head elevating amount in a first elevating section in the head elevating range. Is used to adjust the lift amount of the head, and in the second lift section in the lift range of the head, a second nonlinear approximation formula that approximates the relationship between the rotation amount of the cam and the lift amount of the head. Use to adjust the amount of head lift,
The printing apparatus, wherein the second nonlinear approximate expression is different from the first nonlinear approximate expression. The lift amount of the head in the second lift section is greater than the lift amount of the head in the first lift section,
The printing apparatus according to claim 5, wherein the order of the second nonlinear approximate expression is greater than the order of the first nonlinear approximate expression. The first lifting section is closer to the origin position of the head lifting range than the second lifting section,
The printing apparatus according to claim 5 or 6, wherein the order of the second nonlinear approximation formula is larger than the order of the first nonlinear approximation formula. The cam has a first slope corresponding to the first lifting section and a second slope corresponding to the second lifting section,
The second gradient is greater than the first gradient;
8. The printing apparatus according to claim 5, wherein the order of the second nonlinear approximate expression is larger than the order of the first nonlinear approximate expression. 9. The first lifting section includes a print area of the head,
The printing apparatus according to claim 5, wherein the second elevating section includes a maintenance area for the head.

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