Printer and control method of the same

Abstract

To provide a printer which can maintain taking-up accuracy, and to provide a control method of the printer.SOLUTION: A printer includes: a transport unit; a printing unit; a take-up shaft which takes up a printed medium to support a roll body around which the medium is wound; a tension application unit which contacts with the medium between the printing unit and the take-up shaft to apply tension to the medium; and a control unit. The tension application unit has: a tension bar which contacts with the medium; an arm which supports the tension bar and rotates to displace the tension bar; a stopper which contacts with the tension bar or the arm to restrict the tension bar at a restriction position; and a detection unit which detects a position of the tension bar. The control unit calculates an approach distance from a position of the tension bar detected by the detection unit to the restrict position and, when the approach distance is shorter than or equal to a predetermine distance, causes the take-up shaft to rotate at a target speed lower than a speed when the approach distance is longer than the predetermined distance.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a printing apparatus and a method for controlling the printing apparatus.

Background Art

[0002] Patent Document 1 describes a printing apparatus including a conveyance unit that conveys a medium, a printing unit that prints on the conveyed medium, a winding shaft that winds up the printed medium, and a tension applying unit that applies tension to the medium between the printing unit and the winding shaft. The tension applying unit has a tension bar that contacts the medium and an arm that supports the tension bar. The tension applying unit applies a constant tension to the medium by moving the tension bar as the medium is wound up.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In such a printing apparatus, there may be a stopper that restricts the movement of the tension bar. When the winding shaft winds up the medium, the tension bar moves so as to approach the stopper. When the movement of the tension bar is restricted by the stopper, the tension applied to the medium increases. As a result, the medium is wound tightly.

[0005] When the winding shaft rotates to wind up the medium, the tension bar or the arm may come into forceful contact with the stopper. In this case, there is a risk of affecting the winding accuracy by changing the tension applied to the medium or changing the winding speed.

Means for Solving the Problems

[0006] A printing apparatus for solving the above problems includes a conveyance unit that conveys a medium, a printing unit that prints on the medium conveyed by the conveyance unit, a take-up shaft that supports a roll body in which the medium is wound up by winding up the printed medium, a tension applying unit that applies tension to the medium by contacting the medium between the printing unit and the take-up shaft, and a control unit. The tension applying unit includes a tension bar that contacts the medium, an arm that supports the tension bar and displaces the tension bar by rotating, a stopper that restricts the tension bar at a restricted position by contacting the tension bar or the arm, and a detection unit that detects the position of the tension bar. The control unit calculates an approach distance from the position of the tension bar detected by the detection unit to the restricted position, and when the approach distance is equal to or less than a predetermined distance, rotates the take-up shaft at a lower target speed compared to when the approach distance is greater than the predetermined distance.

[0007] A control method for a printing apparatus for solving the above problems is a control method for a printing apparatus that winds up a medium printed by a printing unit with a take-up shaft, and includes detecting the position of a tension bar that applies tension to the medium by contacting the medium between the printing unit and the take-up shaft, calculating an approach distance from the detected position of the tension bar to a restricted position where the movement of the tension bar is restricted by a stopper, and rotating the take-up shaft at a lower target speed when the approach distance is equal to or less than a predetermined distance compared to when the approach distance is greater than the predetermined distance.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiment for Carrying Out the Invention

[0009] Hereinafter, an embodiment of a printing apparatus will be described with reference to the drawings. The printing apparatus is, for example, an inkjet printer that prints images such as characters and photographs by discharging ink, which is an example of a liquid, onto a medium such as paper or fabric.

[0010] <Printing apparatus> As shown in FIG. 1, the printing apparatus 11 includes a printing unit 12. The printing unit 12 is configured to print on the medium 99.

[0011] The printing apparatus 11 may include a feeding unit 13. The feeding unit 13 is configured to feed the medium 99. The feeding unit 13 feeds the medium 99 toward the printing unit 12. The feeding unit 13 is attached to the printing unit 12. The printing apparatus 11 may receive the medium 99 from a feeding device that feeds the medium 99.

[0012] The printing apparatus 11 includes a winding unit 14. The winding unit 14 is configured to wind up the medium 99. The winding unit 14 winds up the printed medium 99 from the printing unit 12. The winding unit 14 forms a roll body R1 by winding up the medium 99. The roll body R1 is an article in which the medium 99 is wound.

[0013] <Printing unit> First, the printing unit 12 will be described. The printing unit 12 prints on the medium 99 fed from the feeding unit 13. After the medium 99 is printed by the printing unit 12, it is wound up by the winding unit 14. The printing unit 12 prints on the medium 99 between the time when the medium 99 is fed from the feeding unit 13 and the time when it is wound up by the winding unit 14. The printing unit 12 prints on the long medium 99 extending from the feeding unit 13 to the winding unit 14.

[0014] The printing unit 12 includes a housing 21. The printing unit 12 includes legs 22. The legs 22 support the housing 21. The printing unit 12 includes a printing section 23. The printing section 23 is located within the housing 21. The printing section 23 is configured to print on the medium 99. The printing section 23 is a head that discharges liquid onto the medium 99. The printing section 23 is a serial head that scans the medium 99.

[0015] The printing unit 12 includes a support section 24. The support section 24 is located within the housing 21. The support section 24 supports the medium 99. The support section 24 faces the printing section 23. The support section 24 supports the area of the medium 99 that is printed by the printing section 23.

[0016] The printing unit 12 may include an upstream support section 25. The upstream support section 25 may be located within the housing 21 or outside the housing 21. The upstream support section 25 is located upstream of the support section 24 in the conveyance direction of the medium 99. The upstream support section 25 supports the area of the medium 99 that is located upstream of the area supported by the support section 24. By supporting the medium 99, the upstream support section 25 guides the medium 99 from the feeding unit 13 to the support section 24.

[0017] The printing unit 12 may include a downstream support section 26. The downstream support section 26 may be located within the housing 21 or outside the housing 21. The downstream support section 26 is located downstream of the support section 24 in the conveyance direction. The downstream support section 26 supports the area of the medium 99 that is located downstream of the area supported by the support section 24. By supporting the medium 99, the downstream support section 26 guides the medium 99 from the support section 24 to the winding unit 14.

[0018] The printing unit 12 includes a conveyance unit 27. The conveyance unit 27 is configured to convey the medium 99. The conveyance unit 27 is located within the housing 21. The conveyance unit 27 conveys the medium 99 to the printing unit 23. The conveyance unit 27 conveys the medium 99 fed out from the feeding unit 13. The conveyance unit 27 conveys the medium 99 from the feeding unit 13 toward the winding unit 14. In one example, the conveyance unit 27 is located between the support unit 24 and the upstream support unit 25. The conveyance unit 27 is composed of, for example, a pair of rollers. In this case, the conveyance unit 27 conveys the medium 99 by rotating while sandwiching the medium 99.

[0019] The conveyance unit 27 conveys the medium 99 intermittently. That is, the conveyance unit 27 repeats the start and stop of conveyance. The conveyance unit 27 stops the medium 99 while the printing unit 23 discharges liquid onto the medium 99. The conveyance unit 27 conveys the medium 99 while the printing unit 23 does not discharge liquid onto the medium 99. In the printing apparatus 11, the printing of the medium 99 and the conveyance of the medium 99 are alternately repeated.

[0020] The printing unit 12 includes a control unit 28. The control unit 28 controls the printing unit 12. The control unit 28 controls, for example, the printing unit 23 and the conveyance unit 27. The control unit 28 is configured to control the feeding unit 13. The control unit 28 is configured to control the winding unit 14.

[0021] The control unit 28 may be composed of one or more processors that execute various processes according to a computer program. The control unit 28 may be composed of one or more dedicated hardware circuits such as application-specific integrated circuits that execute at least some of the various processes. The control unit 28 may be composed of a circuit including a combination of a processor and a hardware circuit. The processor includes a CPU and a memory such as a RAM and a ROM. The memory stores program code configured to cause the CPU to execute a process or instructions. The memory, that is, the computer-readable medium, includes any readable medium accessible by a general-purpose or dedicated computer.

[0022] The printing unit 12 includes a storage unit 29. The storage unit 29 stores variables indicating the state of the winding unit 14. Specifically, the variables indicate the state of the tension bar 36, which will be described later. In one example, the storage unit 29 stores, as variables, a first flag, a second flag, and a third flag. The storage unit 29 stores the first flag, the second flag, and the third flag exclusively. The storage unit 29 stores one of the first flag, the second flag, and the third flag corresponding to the state of the winding unit 14. The control unit 28 grasps the state of the tension bar 36 based on the variables stored in the storage unit 29. The variables will be described later. In addition to the variables, the storage unit 29 may store programs executed by the control unit 28. The storage unit 29 may be composed of a hard disk, a flash memory, etc. The storage unit 29 may be included in the control unit 28. The storage unit 29 may be composed of a RAM.

[0023] <Winding unit 14> Next, the winding unit 14 will be described. As shown in FIG. 1, the winding unit 14 is attached to the printing unit 12. In one example, the winding unit 14 is attached to the leg portion 22. The winding unit 14 is located below the support portion 24. Therefore, the winding unit 14 winds the medium 99 downward from the printing unit 12.

[0024] The winding unit 14 includes a frame 31. The frame 31 is attached to, for example, the leg portion 22. The frame 31 holds various components included in the winding unit 14. The winding unit 14 includes a winding shaft 32. The winding shaft 32 is a shaft that supports the roll body R1. When the winding shaft 32 rotates, the medium 99 is wound around the winding shaft 32. The winding shaft 32 is attached to the frame 31.

[0025] The take-up unit 14 includes a drive unit 33. The drive unit 33 is configured to rotate the take-up shaft 32. The drive unit 33 includes, for example, a motor. The drive unit 33 is connected to the take-up shaft 32. By rotating the take-up shaft 32 by the drive unit 33, the medium 99 is wound around the take-up shaft 32.

[0026] The take-up unit 14 includes a guide roller 34. The guide roller 34 is attached to the frame 31. The medium 99 wound around the take-up shaft 32 is wound around the guide roller 34. In one example, the medium 99 is wound around the guide roller 34 from above. The guide roller 34 guides the medium 99 wound around the take-up shaft 32. Specifically, the guide roller 34 guides the medium 99 from a tension applying unit 35, which will be described later, to the take-up shaft 32.

[0027] The take-up unit 14 includes a tension applying unit 35. The tension applying unit 35 is configured to apply tension to the medium 99. The tension applying unit 35 applies tension to the medium 99 by contacting the medium 99 between the time when the medium 99 is printed by the printing unit 23 and the time when it is wound around the take-up shaft 32. Specifically, the tension applying unit 35 applies tension to the medium 99 by contacting the medium 99 between the printing unit 23 and the take-up shaft 32. More specifically, the tension applying unit 35 applies tension to the medium 99 by contacting the medium 99 between the conveyance unit 27 and the take-up shaft 32 of the medium 99. By applying appropriate tension to the medium 99 by the tension applying unit 35, the medium 99 is smoothly wound from the printing unit 12 to the take-up unit 14.

[0028] The tension applying unit 35 has a tension bar 36. The tension bar 36 contacts the medium 99. The medium 99 is wound around the tension bar 36. Specifically, the medium 99 guided by the downstream support portion 26 is wound around the tension bar 36. The tension bar 36 is positioned such that the medium 99 is wound around it from below. Therefore, the tension bar 36 applies tension to the medium 99 by pushing the medium 99 downward. The tension bar 36 applies a certain tension to the medium 99 due to its own weight.

[0029] The tension bar 36 is configured to be displaced vertically. The tension bar 36 is displaced while applying a certain tension to the medium 99. The tension bar 36 is displaced according to the difference between the conveyance speed of the medium 99 by the conveyance unit 27 and the winding speed of the medium 99 by the take-up shaft 32. That is, when the conveyance speed is faster than the winding speed, the medium 99 is loosened by the conveyance unit 27. In this case, the tension bar 36 moves downward as the medium 99 is loosened. When the conveyance speed is slower than the winding speed, the medium 99 is pulled by the take-up shaft 32. In this case, the tension bar 36 moves upward as the take-up shaft 32 pulls the medium 99.

[0030] The tension bar 36 is a roller. Therefore, as the medium 99 is wound, the tension bar 36 rotates. Thereby, the friction between the tension bar 36 and the medium 99 is reduced, and the medium 99 is conveyed smoothly. The tension bar 36 may be composed of, for example, a non-rotatable rod.

[0031] As shown in FIG. 2, the tension applying unit 35 has an arm 37. The arm 37 supports the tension bar 36. Specifically, the tension bar 36 is attached to the tip portion of the arm 37.

[0032] The arm 37 is configured to rotate. Specifically, the arm 37 rotates about its proximal end. By rotating, the arm 37 displaces the tension bar 36. That is, when the arm 37 rotates, the tension bar 36 moves up and down.

[0033] The tension applying portion 35 has a rotation mechanism 38. The rotation mechanism 38 is a mechanism for rotating the arm 37. The rotation mechanism 38 has a motor 39. The rotation mechanism 38 may have a plurality of motors 39. The motor 39 rotates the arm 37. The motor 39 displaces the tension bar 36. The motor 39 may constitute the drive unit 33.

[0034] The rotation mechanism 38 has a transmission mechanism 40. The transmission mechanism 40 is a mechanism for transmitting the power of the motor 39 to the arm 37. The transmission mechanism 40 has a drive gear 41, a driven gear 42, and a transmission belt 43. The transmission belt 43 is wound around the drive gear 41 and the driven gear 42.

[0035] The drive gear 41 is connected to the motor 39. The drive gear 41 rotates by the motor 39. The driven gear 42 is connected to the drive gear 41 by the transmission belt 43. Thereby, the driven gear 42 is driven by the drive gear 41. The driven gear 42 rotates as the drive gear 41 rotates.

[0036] The driven gear 42 has a rotating shaft 44. The driven gear 42 rotates about the rotating shaft 44. The arm 37 is attached to the rotating shaft 44. The rotating shaft 44 is attached to the proximal end portion of the arm 37. When the rotating shaft 44 rotates, the arm 37 rotates. Therefore, the driven gear 42 is interlocked with the arm 37. The rotating shaft 44 may be positioned coaxially with the winding shaft 32.

[0037] The tension applying unit 35 has a detection unit 45. The detection unit 45 is configured to detect the position of the tension bar 36. The detection unit 45 may directly detect the position of the tension bar 36. The detection unit 45 may indirectly detect the position of the tension bar 36. For example, the detection unit 45 may detect the position of the tension bar 36 by detecting the position of the arm 37. The detection unit 45 may detect the position of the tension bar 36 by detecting the rotation angle of the arm 37, that is, the rotation angle of the driven gear 42, the rotation angle of the driving gear 41, and the like.

[0038] The detection unit 45 detects the position of the tension bar 36 by detecting the rotation angle of the arm 37. For example, the detection unit 45 has an encoder 46. In one example, the encoder 46 detects the rotation angle of the driven gear 42. The detection unit 45 converts the rotation angle of the driven gear 42 into the rotation angle of the arm 37. Thereby, the detection unit 45 detects the position of the tension bar 36. The encoder 46 may detect not only the rotation angle of the driven gear 42 but also the rotation angle of the driving gear 41.

[0039] By the detection unit 45 detecting the position of the tension bar 36, the position of the tension bar 36 is controlled. Based on the position of the tension bar 36, the rotation of the winding shaft 32 is controlled. By the control unit 28 controlling the motor 39, the winding speed by the winding shaft 32 is controlled.

[0040] In addition to detecting the position of the tension bar 36, the detection unit 45 may detect the movement of the tension bar 36. The detection unit 45 may detect that the tension bar 36 moves upward and that the tension bar 36 moves downward. For example, the detection unit 45 may detect the movement of the tension bar 36 from the change in the rotation angle of the arm 37.

[0041] The detection unit 45 may have one or more position sensors 47. For example, the position sensor 47 is an optical sensor. The position sensor 47 is positioned so as to be blocked by the tension bar 36 or the arm 37. When the position sensor 47 is blocked by the tension bar 36 or the arm 37, the tension bar 36 is detected. Thereby, the detection unit 45 detects the position of the tension bar 36.

[0042] The position sensor 47 is positioned to detect the tension bar 36 at a proximity distance that is a predetermined distance. The proximity distance will be described later. When the detection unit 45 has a plurality of position sensors 47, the plurality of position sensors 47 includes a position sensor 47 that detects the tension bar 36 at a proximity distance that is a predetermined distance. The detection unit 45 may detect the movement of the tension bar 36 by the plurality of position sensors 47. That is, the detection unit 45 can detect the movement of the tension bar 36 based on the detection order of the plurality of position sensors 47.

[0043] The detection unit 45 may have a distance sensor 48. For example, the distance sensor 48 is an optical sensor. The distance sensor 48 detects the distance to the tension bar 36. Thereby, the detection unit 45 detects the position of the tension bar 36. The detection unit 45 can also detect the movement of the tension bar 36 based on the change in the detection distance by the distance sensor 48.

[0044] The detection unit 45 has at least one of the encoder 46, the position sensor 47, and the distance sensor 48. That is, the detection unit 45 may have one, two, or all of the encoder 46, the position sensor 47, and the distance sensor 48. For example, the detection unit 45 may have only the encoder 46, only the position sensor 47, or only the distance sensor 48.

[0045] The tension applying unit 35 has a stopper 51. The stopper 51 is configured to restrict the movement of the tension bar 36. The stopper 51 restricts the movement of the tension bar 36 by contacting the tension bar 36 or the arm 37. In one example, the stopper 51 contacts the tension bar 36. The stopper 51 contacts the tension bar 36 from above. The stopper 51 restricts the upward movement of the tension bar 36.

[0046] The stopper 51 restricts the tension bar 36 at the regulation position P1. The regulation position P1 is the position of the tension bar 36 restricted by the stopper 51. The regulation position P1 is the uppermost position within the movement range of the tension bar 36.

[0047] The stopper 51 contributes to the winding of the medium 99. By the stopper 51 restricting the movement of the tension bar 36, the take-up shaft 32 can wind the medium 99. By winding the medium 99, the slack of the roll body R1 is reduced.

[0048] As the take-up shaft 32 winds the medium 99, the tension bar 36 moves upward. Thereby, the tension bar 36 contacts the stopper 51. At this time, the tension bar 36 is maintained at the regulation position P1. When the take-up shaft 32 winds the medium 99 with the tension bar 36 positioned at the regulation position P1, the tension applied to the medium 99 increases. As a result, the medium 99 is wound.

[0049] The tension applying unit 35 may have a sub-stopper 52. The sub-stopper 52 is configured to restrict the movement of the tension bar 36. The sub-stopper 52 restricts the movement of the tension bar 36 by contacting the tension bar 36 or the arm 37. In one example, the sub-stopper 52 contacts the tension bar 36. The sub-stopper 52 contacts the tension bar 36 from below. The sub-stopper 52 restricts the downward movement of the tension bar 36.

[0050] The stopper 51 and the sub-stopper 52 are positioned so as to sandwich the tension bar 36 vertically. The space between the stopper 51 and the sub-stopper 52 is the moving range of the tension bar 36.

[0051] The control unit 28 may determine the reference angle of the arm 37 based on the fact that the stopper 51 or the sub-stopper 52 restricts the movement of the tension bar 36. In one example, the control unit 28 determines the rotation angle of the arm 37 when the tension bar 36 contacts the stopper 51 as the reference angle. In this case, the reference angle is the angle corresponding to the regulation position P1. The control unit 28 may also determine the rotation angle of the arm 37 when the tension bar 36 contacts the sub-stopper 52 as the reference angle.

[0052] When the position of the tension bar 36 is detected by the encoder 46, a reference angle of the arm 37 serving as a measurement reference for the encoder 46 is required. The detection unit 45 detects the rotation angle of the arm 37 by counting encoder pulses from the reference angle. The reference angle may be stored in advance in the control unit 28, the memory unit 29, etc. The reference angle may be updated based on the fact that the stopper 51 or the sub-stopper 52 restricts the movement of the tension bar 36.

[0053] The control unit 28 causes the tension bar 36 to contact the stopper 51 or the sub-stopper 52 by controlling the motor 39. The control unit 28 detects that the movement of the tension bar 36 is restricted by the stopper 51 based on the detection result of the detection unit 45. Specifically, when the position of the tension bar 36 detected by the detection unit 45 does not change over a predetermined period of time, the control unit 28 detects that the movement of the tension bar 36 is restricted by the stopper 51. The control unit 28 determines the position of the tension bar 36 when its movement is restricted by the stopper 51 as a reference angle. The control unit 28 may detect that the movement of the tension bar 36 is restricted by the stopper 51 based on the torque of the motor 39, for example, the load current of the motor 39. That is, the control unit 28 may determine the rotation angle of the arm 37 detected by the detection unit 45 in a state where a load current that causes the torque of the motor 39 to be equal to or greater than a predetermined value is flowing through the motor 39 as the reference angle.

[0054] <Control of the printing apparatus> Next, the control of the printing apparatus 11 will be described. In particular, the winding of the medium 99 will be described.

[0055] Each time the printing apparatus 11 conveys the medium 99, it winds up the medium 99. The printing apparatus 11 continues to rotate the take-up shaft 32 while the conveyance unit 27 conveys intermittently. During the intermittent conveyance by the conveyance unit 27, the tension bar 36 is displaced vertically. Specifically, when the conveyance of the medium 99 by the conveyance unit 27 stops, the tension bar 36 moves upward. When the conveyance of the medium 99 by the conveyance unit 27 resumes, the tension bar 36 moves downward. The printing apparatus 11 winds up the medium 99 by restricting the movement of the tension bar 36 by the stopper 51 while the conveyance of the medium 99 by the conveyance unit 27 is stopped.

[0056] When the medium 99 is being wound up, if the tension bar 36 or the arm 37 comes into forceful contact with the stopper 51, the tension applied to the medium 99 may change, or the winding speed by the take-up shaft 32 may change. Therefore, if the tension bar 36 or the arm 37 comes into forceful contact with the stopper 51, there is a risk that the medium 99 cannot be wound up correctly. Accordingly, there is a risk of affecting the winding accuracy. In contrast, the printing apparatus 11 rotates the take-up shaft 32 so that the tension bar 36 or the arm 37 comes into slow contact with the stopper 51.

[0057] As shown in FIG. 3, the control unit 28 controls the target speed of the take-up shaft 32 based on the position of the tension bar 36. FIG. 3 includes a graph showing the position of the tension bar 36 and a graph showing the target speed of the take-up shaft 32.

[0058] The control unit 28 rotates the take-up shaft 32 at different target speeds based on the approach distance. When the approach distance is equal to or less than a predetermined distance, the control unit 28 rotates the take-up shaft 32 at a lower target speed than when the approach distance is greater than the predetermined distance. Specifically, when the approach distance is greater than the predetermined distance, the control unit 28 rotates the take-up shaft 32 at a first speed. When the approach distance is equal to or less than the predetermined distance, the control unit 28 rotates the take-up shaft 32 at a second speed. The first speed and the second speed are target speeds. The second speed is lower than the first speed. The approach distance is the distance from the current position of the tension bar 36 to the regulation position P1. The approach distance is the distance from the position of the tension bar 36 detected by the detection unit 45 to the regulation position P1. The predetermined distance is, for example, a threshold value stored in the storage unit 29. The predetermined distance may be indicated by the position detected by the position sensor 47.

[0059] The control unit 28 calculates the approach distance based on the detection result of the detection unit 45. In one example, the approach distance is represented by the rotation angle with respect to the reference angle in the arm 37. The control unit 28 rotates the take-up shaft 32 at the second speed to slowly approach the tension bar 36 to the stopper 51. Thereby, the risk that the tension bar 36 comes into forceful contact with the stopper 51 is reduced.

[0060] In addition to the position of the tension bar 36, the control unit 28 may control the target speed of the take-up shaft 32 based on the movement of the tension bar 36. When the target speed is controlled only based on the position of the tension bar 36, the target speed becomes the second speed even when the tension bar 36 moves away from the stopper 51. In this case, since it takes time to wind up the medium 99, the time for winding up the medium 99 may be shortened. In order to ensure the time for winding up the medium 99, it is preferable that the take-up shaft 32 quickly winds up the medium 99 when the conveyance of the medium 99 by the conveyance unit 27 resumes. Therefore, when the conveyance of the medium 99 by the conveyance unit 27 resumes, the target speed of the take-up shaft 32 is preferably the first speed.

[0061] The control unit 28 sets the target speed to the second speed when the approach distance becomes equal to or less than a predetermined distance from a state where the approach distance is greater than the predetermined distance. That is, the control unit 28 sets the target speed to the second speed when the tension bar 36 approaches the regulation position P1. The control unit 28 sets the target speed to the second speed before the movement of the tension bar 36 is regulated by the stopper 51. The control unit 28 sets the target speed to the first speed when it is located at the regulation position P1. The control unit 28 sets the target speed to the first speed when the position of the tension bar 36 does not change over a predetermined time. Thereby, when the tension bar 36 moves away from the stopper 51, the take-up shaft 32 can rotate at the first speed. Therefore, the time for winding up the medium 99 can be ensured. The control unit 28 may set the position of the tension bar 36 as the regulation position P1 when the position of the tension bar 36 does not change over a predetermined time.

[0062] The control unit 28 may detect the movement of the tension bar 36 based on a variable stored in the storage unit 29. The control unit 28 stores the variable in the storage unit 29 based on the position of the tension bar 36. The control unit 28 stores a first flag, a second flag, and a third flag in the storage unit 29 as variables based on the position of the tension bar 36.

[0063] The first flag is stored when the tension bar 36 is located at the regulation position P1. That is, it is stored when the position of the tension bar 36 does not change over a predetermined time. The first flag is a flag indicating that the tension bar 36 has been located at the regulation position P1.

[0064] The second flag is stored when the approaching distance is greater than a predetermined distance while the storage unit 29 stores the first flag. That is, the second flag is stored when the tension bar 36 moves away from the stopper 51. The second flag is a flag indicating that the tension bar 36 has moved away from the stopper 51.

[0065] The third flag is stored when the approaching distance is equal to or less than the predetermined distance while the storage unit 29 stores the second flag. That is, the third flag is stored when the tension bar 36 approaches the stopper 51. The third flag is a flag indicating that the tension bar 36 has moved so as to approach the stopper 51.

[0066] The control unit 28 controls the target speed based on the detection result of the detection unit 45 and the variables stored in the storage unit 29. The control unit 28 can grasp the position of the tension bar 36 based on the detection result of the detection unit 45. The control unit 28 can grasp the movement of the tension bar 36 based on the variables stored in the storage unit 29. Therefore, in one example, the control unit 28 sets the target speed to the second speed when the approaching distance is equal to or less than the predetermined distance while the storage unit 29 stores the second flag. The control unit 28 may grasp the movement of the tension bar 36 by the detection unit 45, not limited to variables.

[0067] Next, an example of the winding process will be described. The winding process starts together with the start of printing of the medium 99. The winding process is executed in parallel with the intermittent conveyance of the medium 99. The control unit 28, for example, resets the variable at the start of the winding process. In one example, the control unit 28 controls the motor 39 at the start of the winding process to bring the tension bar 36 into contact with the stopper 51 and stores the first flag in the storage unit 29.

[0068] As shown in FIG. 4, in step S11, the control unit 28 rotates the take-up shaft 32. At this time, the control unit 28 rotates the take-up shaft 32 at the first speed. In step S12, the control unit 28 determines whether the approach distance is greater than a predetermined distance. At this time, the control unit 28 determines whether the approach distance is greater than the predetermined distance based on the detection result of the detection unit 45. If the approach distance is greater than the predetermined distance, the control unit 28 proceeds to step S13. If the approach distance is less than or equal to the predetermined distance, the control unit 28 repeats step S12.

[0069] In step S13, the control unit 28 stores the second flag in the storage unit 29. After the control unit 28 stores the second flag in the storage unit 29, it proceeds to step S14. In step S14, the control unit 28 determines whether the approach distance is less than or equal to the predetermined distance. At this time, the control unit 28 determines whether the approach distance is less than or equal to the predetermined distance based on the detection result of the detection unit 45. If the approach distance is less than or equal to the predetermined distance, the control unit 28 proceeds to step S15. If the approach distance is greater than the predetermined distance, the control unit 28 repeats step S14.

[0070] In step S15, the control unit 28 sets the target speed of the take-up shaft 32 to the second speed. That is, when the second flag is stored and the approach distance is less than or equal to the predetermined distance, the control unit 28 sets the target speed to the second speed. After the control unit 28 sets the target speed to the second speed, it proceeds to step S16.

[0071] In step S16, the control unit 28 stores the third flag in the storage unit 29. After the control unit 28 stores the third flag in the storage unit 29, it proceeds to step S17. In step S17, the control unit 28 determines whether the tension bar 36 has stopped. Specifically, the control unit 28 determines whether the position of the tension bar 36 has changed over a predetermined time. If the position of the tension bar 36 has not changed over a predetermined time, the control unit 28 determines that the tension bar 36 continues to be located at the regulation position P1. Based on the fact that the tension bar 36 continues to be located at the regulation position P1, the control unit 28 determines that the winding of the medium 99 is completed. When the tension bar 36 continues to be located at the regulation position P1, the control unit 28 transfers the process to step S18. When the tension bar 36 is not located at the regulation position P1, the control unit 28 repeats the process of step S17.

[0072] In step S18, the control unit 28 sets the target speed of the take-up shaft 32 to the first speed. Thereby, after the conveyance of the medium 99 by the conveyance unit 27 resumes, the take-up shaft 32 can quickly wind up the medium 99. After setting the target speed to the first speed, the control unit 28 transfers the process to step S19.

[0073] In step S19, the control unit 28 causes the storage unit 29 to store the first flag. After causing the storage unit 29 to store the first flag, the control unit 28 transfers the process to step S20. In step S20, the control unit 28 updates the regulation position P1. The control unit 28 updates the position of the tension bar 36 in step S15 as the regulation position P1. That is, the control unit 28 sets the rotation angle of the arm 37 in step S15 as the reference angle. After updating the regulation position P1, the control unit 28 transfers the process to step S21.

[0074] In step S21, the control unit 28 determines whether printing has ended. If printing has ended, the control unit 28 stops the take-up shaft 32 and then ends the winding process. If printing has not ended, the control unit 28 transfers the process to step S12. The control unit 28 repeats the above process until printing ends.

[0075] <Actions and Effects of the Embodiment> Next, the actions and effects of the above embodiment will be described. (1) When the approach distance is equal to or less than a predetermined distance, the control unit 28 rotates the take-up shaft 32 at a lower target speed than when the approach distance is greater than the predetermined distance. According to the above configuration, as the tension bar 36 approaches the regulation position P1, the target speed of the take-up shaft 32 decreases. Thereby, the possibility that the tension bar 36 or the arm 37 forcefully contacts the stopper 51 is reduced. Therefore, the winding accuracy is maintained.

[0076] (2) When the tension bar 36 is located at the regulation position P1, the control unit 28 sets the target speed to the first speed. When the approach distance changes from a state greater than the predetermined distance to a state equal to or less than the predetermined distance, the control unit 28 sets the target speed to the second speed. According to the above configuration, the possibility that the target speed is set to the second speed immediately after the target speed is set to the first speed is reduced. That is, when the tension bar 36 moves away from the regulation position P1, the possibility that the target speed is set to the second speed is reduced. Thereby, the take-up shaft 32 can quickly wind the medium 99.

[0077] (3) When the tension bar 36 is located at the regulation position P1, the control unit 28 causes the storage unit 29 to store the first flag. When the approach distance is greater than the predetermined distance while the storage unit 29 stores the first flag, the control unit 28 causes the storage unit 29 to store the second flag. When the approach distance is equal to or less than the predetermined distance while the storage unit 29 stores the second flag, the control unit 28 sets the target speed to the second speed. According to the above configuration, the control unit 28 can grasp whether the tension bar 36 is away from the regulation position P1 or approaching the regulation position P1 based on the variables. Therefore, the possibility that the target speed is set to the second speed when the tension bar 36 moves away from the regulation position P1 is reduced.

[0078] (4) When the position of the tension bar 36 detected by the detection unit 45 does not change over a predetermined time, the control unit 28 sets the target speed to the first speed. When the position of the tension bar 36 does not change over a predetermined time, it is highly likely that the movement of the tension bar 36 is restricted by the stopper 51. According to the above configuration, based on the detection result of the detection unit 45, it is possible to grasp that the tension bar 36 is located at the regulation position P1.

[0079] (5) When the position of the tension bar 36 detected by the detection unit 45 does not change over a predetermined time, the control unit 28 sets the position of the tension bar 36 detected by the detection unit 45 as the regulation position P1. According to the above configuration, the accuracy of the regulation position P1 is improved.

[0080] (6) The detection unit 45 has an encoder 46 that detects the rotation angle of the arm 37. According to the above configuration, based on the rotation angle of the arm 37, it is possible to grasp the position of the tension bar 36.

[0081] (7) The detection unit 45 has a position sensor 47 that detects the tension bar 36 located at a position where the approach distance is a predetermined distance. According to the above configuration, based on the position sensor 47 detecting the tension bar 36, it is possible to grasp the position of the tension bar 36.

[0082] (8) The detection unit 45 has a distance sensor 48 that detects the distance to the tension bar 36. According to the above configuration, the distance sensor 48 can be used to grasp the position of the tension bar 36.

[0083] <Modified Example> The above embodiment can be implemented with the following modifications. The above embodiment and the following modified examples can be implemented in combination with each other within a technically non - conflicting range.

[0084] ·The control unit 28 may control the target speed based only on the position of the tension bar 36. When the approaching distance is equal to or less than a predetermined distance, the control unit 28 may set the target speed to the second speed. When the approaching distance is greater than the predetermined distance, the control unit 28 may set the target speed to the first speed.

[0085] ·The plurality of position sensors 47 may include a position sensor 47 positioned to detect the tension bar 36 located at the regulation position P1. Thereby, the detection unit 45 can easily detect that the tension bar 36 is located at the regulation position P1.

[0086] ·The control unit 28 may linearly change the target speed of the take-up shaft 32, or may non-linearly change it. For example, the control unit 28 may change the target speed of the take-up shaft 32 in a quadratic function.

[0087] ·The printing unit 23 may be a line head capable of discharging liquid all at once across the width of the medium 99. In this case, the conveyance unit 27 continuously conveys the medium 99. In this modified example, the control unit 28 tightens the medium 99 at the timing when printing is completed.

[0088] ·The liquid discharged by the printing unit 23 is not limited to ink, and may be, for example, a liquid in which particles of a functional material are dispersed or mixed in a liquid. For example, the printing unit 23 may discharge a liquid containing a material such as an electrode material or a pixel material used in the manufacture of a liquid crystal display, an electroluminescence display, and a surface-emitting display in a dispersed or dissolved form.

[0089] <Technical idea> The technical idea and its effects grasped from the above-described embodiments and modified examples will be described below.

[0090] (A) The printing apparatus includes a conveyance unit that conveys a medium, a printing unit that prints on the medium conveyed by the conveyance unit, a take-up shaft that supports a roll body in which the media are wound by taking up the printed medium, a tension applying unit that applies tension to the medium by contacting the medium between the printing unit and the take-up shaft, and a control unit. The tension applying unit includes a tension bar that contacts the medium, an arm that supports the tension bar and displaces the tension bar by rotating, a stopper that regulates the tension bar at a regulated position by contacting the tension bar or the arm, and a detection unit that detects the position of the tension bar. The control unit calculates an approach distance from the position of the tension bar detected by the detection unit to the regulated position, and when the approach distance is equal to or less than a predetermined distance, rotates the take-up shaft at a lower target speed compared to when the approach distance is greater than the predetermined distance. According to the above configuration, as the tension bar approaches the regulated position, the target speed of the take-up shaft decreases. Thereby, the possibility that the tension bar or the arm violently contacts the stopper is reduced. Therefore, the winding accuracy is maintained.

[0091] (B) In the printing apparatus, the control unit may set the target speed to a first speed when the tension bar is positioned at the regulated position, and set the target speed to a second speed that is lower than the first speed when the approach distance changes from a state greater than the predetermined distance to equal to or less than the predetermined distance. According to the above configuration, the possibility that the target speed is set to the second speed immediately after the target speed is set to the first speed is reduced. That is, the possibility that the target speed is set to the second speed when the tension bar moves away from the regulated position is reduced. Thereby, the take-up shaft can quickly take up the medium.

[0092] (C) The printing device includes a storage unit that stores a variable indicating the state of the tension bar. When the tension bar is located at the regulation position, the control unit causes the storage unit to store a first flag as the variable. When the approach distance is greater than the predetermined distance while the storage unit stores the first flag, the control unit causes the storage unit to store a second flag as the variable. When the approach distance is less than or equal to the predetermined distance while the storage unit stores the second flag, the control unit may set the target speed to the second speed. According to the above configuration, the control unit can grasp whether the tension bar is away from the regulation position or approaching the regulation position based on the variable. Therefore, the possibility that the target speed is set to the second speed when the tension bar moves away from the regulation position is reduced.

[0093] (D) In the printing device, when the position of the tension bar detected by the detection unit does not change over a predetermined time, the control unit may set the target speed to the first speed. When the position of the tension bar does not change over a predetermined time, it is highly likely that the movement of the tension bar is restricted by a stopper. According to the above configuration, based on the detection result of the detection unit, it can be grasped that the tension bar is located at the regulation position.

[0094] (E) In the printing device, when the position of the tension bar detected by the detection unit does not change over the predetermined time, the control unit may set the position of the tension bar detected by the detection unit as the regulation position. According to the above configuration, the accuracy of the regulation position is improved.

[0095] (F) In the printing device, the detection unit may include an encoder that detects the rotation angle of the arm. According to the above configuration, the position of the tension bar can be grasped based on the rotation angle of the arm.

[0096] (G) In the above printing apparatus, the detection unit may include a position sensor that detects the tension bar located at a position where the approach distance is the predetermined distance. According to the above configuration, by the position sensor detecting the tension bar, the position of the tension bar can be grasped.

[0097] (H) In the above printing apparatus, the detection unit may include a distance sensor that detects the distance to the tension bar. According to the above configuration, by the distance sensor, the position of the tension bar can be grasped.

[0098] (I) A control method for a printing apparatus is a control method for a printing apparatus that winds a printed medium by a take-up shaft by a printing unit, detecting the position of a tension bar that applies tension to the medium by contacting the medium between the printing unit and the take-up shaft, calculating an approach distance from the detected position of the tension bar to a regulation position where the movement of the tension bar is regulated by a stopper, and when the approach distance is equal to or less than a predetermined distance, rotating the take-up shaft at a lower target speed compared to when the approach distance is greater than the predetermined distance. According to the above method, the same effect as the above-described printing apparatus can be obtained.

Description of Reference Numerals

[0099] 11…Printing apparatus, 12…Printing unit, 13…Feeding unit, 14…Take-up unit, 21…Housing, 22…Legs, 23…Printing section, 24…Support section, 25…Upstream support section, 26…Downstream support section, 27…Conveying section, 28…Control section, 29…Storage section, 31…Frame, 32…Take-up shaft, 33…Drive section, 34…Guide roller, 35…Tension applying section, 36…Tension bar, 37…Arm, 38…Rotation mechanism, 39…Motor, 40…Transmission mechanism, 41…Drive gear, 42…Driven gear, 43…Transmission belt, 44…Rotation shaft, 45…Detection unit, 46…Encoder, 47…Position sensor, 48…Distance sensor, 51…Stopper, 52…Sub-stopper, 99…Medium, P1…Regulation position, R1…Roll body.

Claims

1. A conveying unit for conveying a medium, A printing unit for printing on the medium conveyed to the conveying unit, A winding shaft that supports a roll body in which the medium is wound by winding up the printed medium, A tension applying unit that applies tension to the medium by contacting the medium between the printing unit and the winding shaft, A control unit, and comprising, The tension applying unit, A tension bar that contacts the medium, An arm that supports the tension bar and displaces the tension bar by rotating, A stopper that regulates the tension bar at a regulated position by contacting the tension bar or the arm, A detection unit that detects the position of the tension bar, and having, The control unit, Calculates the approach distance from the position of the tension bar detected by the detection unit to the regulated position, A printing apparatus characterized in that when the approach distance is equal to or less than a predetermined distance, the winding shaft is rotated at a lower target speed than when the approach distance is greater than the predetermined distance.

2. The control unit, When the tension bar is located at the regulated position, sets the target speed to a first speed, When the approach distance changes from a state greater than the predetermined distance to a state equal to or less than the predetermined distance, sets the target speed to a second speed smaller than the first speed. Claim 1 The printing apparatus according to the above.

3. Comprises a storage unit for storing a variable indicating the state of the tension bar, The control unit, When the tension bar is located at the regulated position, causes the storage unit to store a first flag as the variable, When the approach distance is greater than the predetermined distance in a state where the storage unit stores the first flag, causes the storage unit to store a second flag as the variable, The printing apparatus according to claim 2, characterized in that when the approach distance is equal to or less than the predetermined distance in a state where the storage unit stores the second flag, the target speed is set to the second speed.

4. The control unit sets the target speed to the first speed when the position of the tension bar detected by the detection unit does not change over a predetermined time. The printing apparatus according to claim 3.

5. The printing apparatus according to claim 4, wherein the control unit sets the position of the tension bar detected by the detection unit as the regulation position when the position of the tension bar detected by the detection unit does not change over the predetermined time.

6. The printing apparatus according to any one of claims 2 to 5, wherein the detection unit includes an encoder that detects the rotation angle of the arm.

7. The printing apparatus according to any one of claims 2 to 5, wherein the detection unit includes a position sensor that detects the tension bar located at a position where the approach distance becomes the predetermined distance.

8. The printing apparatus according to any one of claims 2 to 5, wherein the detection unit includes a distance sensor that detects the distance to the tension bar.

9. A control method for a printing apparatus that winds a medium printed by a printing unit with a winding shaft, the method including: detecting a position of a tension bar that applies tension to the medium by contacting the medium between the printing unit and the winding shaft; calculating an approach distance from the detected position of the tension bar to a regulation position at which movement of the tension bar is regulated by a stopper; and rotating the winding shaft at a lower target speed when the approach distance is equal to or less than a predetermined distance than when the approach distance is greater than the predetermined distance.

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