JP2018171750A - Conveying apparatus, printing apparatus, conveying method, and conveying program - Google Patents

Abstract

Provided are a transport device that can transport an ink ribbon by applying an appropriate tension, a printing device that performs printing using an ink ribbon transported by the transport device, a transport method, and a transport program. A printing apparatus rotates at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted, and conveys the ink ribbon between the ribbon rolls mounted on each shaft (S13). ). The printing apparatus acquires the first tension detected by the tension detection unit when the ink ribbon is transported so that the transport amount of the ink ribbon at a predetermined position becomes the first amount (S15). The printing apparatus acquires the second tension detected by the tension detection unit when the ink ribbon is transported so that the transport amount of the ink ribbon at a predetermined position becomes the second amount (S19). The printing apparatus determines the initial tension of the ink ribbon from the first tension and the second tension (S23). [Selection] Figure 5

Description

  The present invention relates to a transport apparatus that transports an ink ribbon, a printing apparatus that performs printing using an ink ribbon transported by the transport apparatus, a transport method, and a transport program.

  There is known a thermal transfer type printing apparatus that performs printing by heating an ink ribbon. When the printing of the ink ribbon is started and printing is started, there is a high possibility that the ink ribbon is loose. If the ink ribbon is loosened, wrinkles may occur on the ink ribbon, which may adversely affect print quality. For this reason, for example, the printing apparatus may start printing with tension applied to the ink ribbon. At this time, if the tension applied to the ink ribbon is too small, the slack of the ink ribbon is not eliminated, and wrinkles and meandering occur in the conveyed ink ribbon. If the tension applied to the ink ribbon is too large, the conveyed ink ribbon breaks.

  Patent Document 1 discloses a printing system including a supply unit, a winding unit, a tension detection unit, a conveyance roller, and a control unit. In the printing system, the ink ribbon is conveyed from the supply unit toward the winding unit. The tension detection unit outputs a signal corresponding to the tension of the conveyed ink ribbon to the control unit. The controller holds the tension of the ink ribbon constant by controlling the transport motor in accordance with the signal output from the tension detector.

JP 2010-221503 A

  If the tension applied to the conveyed ink ribbon is too large, the ink ribbon may break. On the other hand, by applying the technique described in Patent Document 1 and executing control to suppress tension when a certain level of tension is applied to the ink ribbon, it is considered that the ink ribbon can be prevented from being broken. .

  However, the resistance to the tension of the ink ribbon may be different for each mounted ink ribbon. Accordingly, it is not possible to uniformly specify an appropriate tension applied to the ink ribbon at the start of conveyance. In the case of the printing system described in Patent Document 1, the control unit controls the transport motor in accordance with the signal output from the tension detection unit. Therefore, before the signal is output from the tension detection unit, the ink ribbon The tension cannot be suppressed. For this reason, there is a problem that the breakage of the ink ribbon according to the application of tension cannot be prevented appropriately.

  An object of the present invention is to provide a transport device that can transport an ink ribbon by applying an appropriate tension, a printing device that performs printing using the ink ribbon transported by the transport device, a transport method, and a transport program.

  The transport device according to the first aspect of the present invention rotates at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted, and the ink between the ribbon rolls mounted on the respective shafts. A first conveying unit that conveys a ribbon; a tension detection unit that detects a parameter corresponding to the tension of the ink ribbon that is conveyed between the ribbon rolls; and the ink ribbon that is mounted by the first conveying unit. A first acquisition unit configured to acquire a first tension based on a parameter detected by the tension detection unit when the ink ribbon is transported so that a transport amount from a predetermined state becomes a first amount; When the ink ribbon is transported by the transport means so that the transport amount of the mounted ink ribbon from the predetermined state is the second amount, the tension is Based on parameters detected by the detection unit, second acquisition means for acquiring a second tension, the first tension when the ink ribbon is transported in the first amount, and the ink ribbon transporting in the second amount Determining means for determining the initial tension of the ink ribbon from the respective values of the second tension in the case of being performed.

  The conveyance device can specify a parameter (for example, the width and thickness of the ink ribbon) indicating the resistance to the tension of the ink ribbon from the acquired first tension and second tension. The transport device can calculate an appropriate initial tension applied to the ink ribbon based on the specified parameter. Therefore, for example, the transport device can suppress loosening while suppressing breakage of the ink ribbon by applying an appropriate initial tension to the ink ribbon.

  In the first aspect, the apparatus may further include a second transport unit that starts transporting the ink ribbon by applying the initial tension determined by the determining unit to the ink ribbon. In this case, the transport device can suppress the slack of the ink ribbon while suppressing breakage of the ink ribbon at the start of transport of the ink ribbon. For this reason, the conveyance device can appropriately convey the ink ribbon.

  1st aspect WHEREIN: The said 1st conveyance means rotates the 1st shaft among the said 2 shafts, and winds the said ink ribbon to the winding roll which is the said ribbon roll with which the said 1st shaft was mounted | worn. The first acquisition means is configured to obtain the first tension when the first shaft is rotated by an amount of rotation by which the first ribbon is wound on the take-up roll by the first amount. The second acquisition means rotates the first shaft by an amount of rotation by which the first conveying means causes the winding roll to wind the ink ribbon by the second amount larger than the first amount. You may acquire the said 2nd tension | tensile_strength when letting it be made. In this case, the transport device can specify a parameter indicating resistance to the tension of the ink ribbon from the first tension and the second tension when the transport amount of the ink ribbon in the same direction is the first amount and the second amount.

  1st aspect WHEREIN: The said 1st conveyance means is the said winding roll in the state which stopped rotation of the supply roll which is the said ribbon roll with which the 2nd shaft different from the said 1st shaft was mounted | worn. The take-up roll may be rotated to convey the ink ribbon from the supply roll toward the take-up roll. In this case, the transport device can specify a parameter indicating resistance to the tension in the ink ribbon based on the amount of elongation when the ink ribbon is stretched according to transport.

  In the first aspect, the tension detection unit detects the tension by detecting a position of a moving body that moves in accordance with the tension of the ink ribbon conveyed between the ribbon rolls, and The acquisition unit and the second acquisition unit may acquire the tension in a state where the movable body of the tension detection unit is disposed at a position within a predetermined movement range. In this case, the transport device can accurately detect the tension with the tension sensor.

  1st aspect WHEREIN: The said 1st conveyance means rotates the 1st shaft among the said 2 shafts, and winds the said ink ribbon to the winding roll which is the said ribbon roll with which the said 1st shaft was mounted | worn. The ink ribbon is transported from the supply roll, which is the ribbon roll mounted on the second shaft different from the first shaft of the two shafts, toward the take-up roll, and the initial tension is determined by the determining unit. Is determined, and the third transport for transporting the ink ribbon for the transport amount of the ink ribbon wound around the take-up roll by the first transport means from the take-up roll toward the supply roll. And the second conveying means, after the ink ribbon is conveyed by the third conveying means, from the supply roll toward the winding roll, The serial ink ribbon, the initial tension may be transported in a state of action. In this case, the conveyance device can also use a part of the ink ribbon used for calculating the initial tension of the ink ribbon for printing.

  A printing apparatus according to a second aspect of the present invention includes the transport apparatus according to the first aspect and a printing unit that performs printing on the ink ribbon transported by the transport apparatus. According to the 2nd aspect, there can exist an effect similar to a 1st aspect. Further, in this case, the printing apparatus can perform printing using the ink ribbon in a state in which the slack is eliminated, so that good print quality can be realized.

  The transport method according to the third aspect of the present invention is such that at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted is rotated, and the ink ribbon is interposed between the ribbon rolls mounted on the respective shafts. When the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the first amount by the first transport step for transporting the ink ribbon, the tension detection unit Based on the detected parameter, the first acquisition step of acquiring the first tension and the ink transporting amount so that the transport amount of the mounted ink ribbon from the predetermined state becomes the second amount by the first transport step. A second acquisition step of acquiring a second tension based on a parameter detected by the tension detector when the ribbon is conveyed; The initial tension of the ink ribbon is determined from the respective values of the first tension when the ink ribbon is transported by the first amount and the second tension when the ink ribbon is transported by the second amount. And a determining step. According to the 3rd aspect, there can exist an effect similar to a 1st aspect.

  According to a fourth aspect of the present invention, there is provided a transport program that rotates at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted, and the ink ribbon between the ribbon rolls mounted on the respective shafts. When the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the first amount by the first transport step for transporting the ink ribbon, the tension detection unit Based on the detected parameter, the first acquisition step of acquiring the first tension and the ink transporting amount so that the transport amount of the mounted ink ribbon from the predetermined state becomes the second amount by the first transport step. A second acquisition step of acquiring a second tension based on a parameter detected by the tension detector when the ribbon is conveyed; From the respective values of the first tension when the ink ribbon is transported by the first amount and the second tension when the ink ribbon is transported by the second amount, the initial tension of the ink ribbon is determined. The determination step of determining is executed by the computer of the transport apparatus. According to the 4th aspect, there can exist an effect similar to a 1st aspect.

2 is a diagram illustrating an outline of the printing apparatus 1 and a ribbon assembly 90. FIG. It is a figure which shows operation | movement of the sensor assembly. FIG. 2 is a block diagram illustrating an electrical configuration of the printing apparatus 1. 6 is a graph showing a stress-strain curve of the ink ribbon 9. It is a flowchart which shows a main process. 6 is a graph showing the relationship between the transport amount of the ink ribbon 9 and the tension.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The printing apparatus 1 is a thermal transfer type printing apparatus. As shown in FIG. 1, the printing apparatus 1 has a box-shaped housing 10. A metal base plate 10 </ b> A is fixed inside the housing 10. Ribbon mounting portion 2, thermal head 3, sensor assembly 4, guide shafts 61 to 64 (collectively referred to as “guide shaft 60”), control unit 31 (see FIG. 3), motors 81, 82, and 83 (see FIG. 3) ) (Hereinafter collectively referred to as “motor 80” (see FIG. 3)) is provided on the base plate 10A and is accommodated in the housing 10. Hereinafter, in order to facilitate understanding of the description of the drawings, the upper side, the lower side, the left side, the right side, the front side, and the rear side of the printing apparatus 1 are defined. The upper side, lower side, left side, right side, front side, and rear side of the printing apparatus 1 correspond to the upper side, lower side, left side, right side, front side, and back side of FIG.

<Ribbon assembly 90>
A ribbon assembly 90 is mounted on the ribbon mounting portion 2 of the printing apparatus 1. The printing apparatus 1 performs printing by transferring ink to the printing medium P by heating the ink ribbon 9 of the ribbon assembly 90 with the thermal head 3. The ribbon assembly 90 has core shafts 90 </ b> A and 90 </ b> B and an ink ribbon 9. The core shafts 90A and 90B are each cylindrical. The ink ribbon 9 has one end connected to the side surface of the core shaft 90A and the other end connected to the side surface of the core shaft 90B. The ink ribbon 9 is a belt-like film, and an ink layer is applied to the surface of a substrate film such as polyethylene terephthalate (PET). As the base film, for example, any of a plurality of base films having different thicknesses in the range of 2 μm to 10 μm is used. The ink layer includes, for example, a pigment component such as carbon and a binder component such as wax and / or resin. The ink is melted by heating and transferred to the printing medium P.

  The ribbon assembly 90 is mounted on the ribbon mounting portion 2 of the printing apparatus 1 in a state where the ink ribbon 9 is wound around the core shaft 90A. The ink ribbon 9 wound around the core shaft 90A is referred to as “supply roll 9A”. The ink ribbon 9 wound around the core shaft 90B is referred to as “winding roll 9B”. The ink ribbon 9 is unwound from the supply roll 9A of the core shaft 90A in the course of printing by the thermal head 3, and is guided by the sensor assembly 4, the thermal head 3, and the guide shaft 60, which will be described later. It is wound on a roll 9B. The direction of rotation of each of the core shafts 90A and 90B when the ink ribbon 9 is unwound from the supply roll 9A and taken up by the take-up roll 9B is referred to as “normal rotation direction”. The ink ribbon 9 is unwound from the take-up roll 9B and taken up by the supply roll 9A by rotating the core shafts 90A and 90B in the direction opposite to the normal direction (hereinafter referred to as “reverse direction”). Sometimes.

<Ribbon mounting part 2>
The ribbon mounting portion 2 has shafts 21 and 22. Each of the shafts 21 and 22 is rotatable around a rotation axis extending in the front-rear direction. The shaft 21 is provided at the approximate center in the up-down direction of the base plate 10A and on the right side of the center in the left-right direction. The shaft 22 is provided at the substantially vertical center of the base plate 10A and on the left side of the horizontal center. A supply roll 9 </ b> A wound around the core shaft 90 </ b> A of the ribbon assembly 90 is attached to the shaft 21. A winding roll 9 </ b> B wound around the core shaft 90 </ b> B of the ribbon assembly 90 is attached to the shaft 22. The shaft 21 is directly connected to a motor 81 (see FIG. 3, described later) and is rotated by the motor 81. Since the rotation axis of the shaft 21 and the motor 81 coincide with each other, the rotation amount of the motor 81 is equal to the rotation amount of the shaft 21. The shaft 22 is directly connected to a motor 82 (see FIG. 3, described later) and is rotated by the motor 82. Since the rotation axis of the shaft 22 and the motor 82 coincide with each other, the rotation amount of the motor 82 is equal to the rotation amount of the shaft 22. Since the shafts 21 and 22 are rotated by different motors 80, they can be rotated at different rotational speeds.

  As shown in FIG. 1, when the shafts 21 and 22 rotate counterclockwise with the printing apparatus 1 viewed from the front side, the core shafts 90A and 90B rotate in the forward rotation direction. At this time, the ink ribbon 9 is unwound from the supply roll 9A and taken up by the take-up roll 9B. When the shafts 21 and 22 rotate clockwise with the printing apparatus 1 viewed from the front side, the core shafts 90A and 90B rotate in the reverse direction. The ink ribbon 9 is unwound from the take-up roll 9B and taken up by the supply roll 9A. The forward rotation direction of the core shafts 90A and 90B is not limited to the clockwise direction. For example, depending on the winding state of the ink ribbon 9, at least one of the forward rotation directions of the supply roll 9A and the take-up roll 9B may be a clockwise direction.

  The ink ribbon 9 stretched between the supply roll 9 </ b> A and the take-up roll 9 </ b> B according to the rotation of the shafts 21 and 22 is conveyed in the housing 10. The ink ribbon 9 is guided by contact with a sensor assembly 4 and a guide shaft 60 which will be described later. The thermal head 3 to be described later is disposed adjacent to the ink ribbon 9 that is stretched between the supply roll 9A and the take-up roll 9B. A path through which the ink ribbon 9 is transported along the thermal head 3, the sensor assembly 4, and the guide shaft 60 is referred to as a “transport path R”.

<Sensor assembly 4>
The sensor assembly 4 is provided near the upper right corner of the base plate 10A. The sensor assembly 4 has a function as a tension arm that maintains the tension of the ink ribbon 9 by changing the length of the transport path R of the ink ribbon 9, and a function as a position sensor that detects the position of the tension arm. The sensor assembly 4 may be provided at least at a position where the direction along the transport path R of the ink ribbon 9 is changed. Note that the tension arm includes not only a structure that rotates about a predetermined fulcrum but also a structure that moves linearly as shown in FIG. The sensor assembly 4 includes a restriction portion 40 (see FIG. 1), a support portion 41, a guide shaft 42, a magnet 43, a magnetic sensor 44, and a spring 45. The restriction arm 40, the support portion 41, the guide shaft 42, and the spring 45 constitute the tension arm 4A, and the magnet 43 and the magnetic sensor 44 constitute the position sensor 4B.

  The support portion 41 is supported on the rear side of the base plate 10A so as to be movable in the vertical direction. The guide shaft 42 has a cylindrical shape and extends from the front surface of the support portion 41 toward the front side through a restriction portion 40 (described later). The guide shaft 42 projects forward from the front surface of the base plate 10A. The guide shaft 42 is rotatable around a rotation axis that extends in the front-rear direction. As shown in FIG. 1, the restricting unit 40 prohibits the movement of the guide shaft 42 in the left-right direction and restricts the movement of the guide shaft 42 in the vertical direction within a predetermined range. The restricting portion 40 is, for example, a long hole that is provided in the base plate 10A and extends in the vertical direction.

  As shown in FIG. 2, the guide shaft 42 moves vertically between the upper end reference position C (0) and the lower end maximum position C (m) in accordance with the movement of the support portion 41 in the vertical direction. It is movable. A range from a position spaced C (a) below the reference position C (0) to a position spaced C (b) below the reference position C (0) is referred to as a movement range C (ab). The reference position C (0) and the maximum position C (m) are not included in the movement range C (ab). The movement range C (ab) is narrower than the range from the reference position C (0) to the maximum position C (m).

  The magnet 43 extends from the rear surface of the support portion 41 toward the rear side. The magnet 43 is a permanent magnet. The guide shaft 42 and the magnet 43 are movable in the vertical direction according to the movement of the support portion 41.

  The magnetic sensor 44 is provided on the base plate 10B extending rearward from the rear surface of the base plate 10A. The magnetic sensor 44 faces the lower side of the magnet 43. The magnetic sensor 44 is for detecting the magnetic force of the magnet 43, and is composed of, for example, a Hall element. The magnitude of the magnetic force detected by the magnetic sensor 44 changes according to the movement of the magnet 43 in the vertical direction. The spring 45 is a coil spring. One end portion of the spring 45 is connected to the upper surface of the support portion 41. The other end of the spring 45 is connected to a base plate 10C that extends rearward from the rear surface of the base plate 10A. The spring 45 is a tension spring that biases the support portion 41, the guide shaft 42, and the magnet 43 upward.

  As shown in FIG. 1, the ink ribbon 9 contacts a part of the peripheral surface of the guide shaft 42. The transport path R of the ink ribbon 9 extends from the supply roll 9A attached to the shaft 21 toward the upper right side, contacts the guide shaft 42, changes its direction, and extends downward to the guide shaft 61 (described later).

  A downward force corresponding to the tension of the ink ribbon 9 acts on the guide shaft 42 when the ink ribbon 9 contacts the upper region. More specifically, the guide shaft 42 includes a downward component of the tension of the ink ribbon 9 extending from the guide shaft 42 toward the supply roll 9 </ b> A, and the tension of the ink ribbon 9 extending from the guide shaft 42 toward the guide shaft 61. The resultant force acts in the downward direction. The guide shaft 42 stops in a state where the component acting downward of the tension of the ink ribbon 9 and the biasing force of the spring 45 are balanced. As shown in FIG. 2, the smaller the downward force f acting on the guide shaft 42 according to the tension of the ink ribbon 9, the more the guide shaft 42 moves upward by the biasing force of the spring 45. The greater the downward force f acting on the guide shaft 42 according to the tension of the ink ribbon 9, the lower the guide shaft 42 and the magnet 43 move against the biasing force of the spring 45. That is, the length of the transport path R of the ink ribbon 9 changes according to the magnitude of the tension acting on the ink ribbon 9. When the tension acting on the ink ribbon 9 is large, the length of the transport path R of the ink ribbon 9 is shortened, and when the tension acting on the ink ribbon 9 is small, the length of the transport path R of the ink ribbon 9 is lengthened.

  The magnetic sensor 44 detects a magnetic force that changes according to the vertical position of the magnet 43. That is, the magnetic force detected by the magnetic sensor 44 changes according to the tension of the ink ribbon 9. The sensor assembly 4 outputs a signal indicating a value corresponding to the magnetic force detected by the magnetic sensor 44 to the control unit 31 (see FIG. 3). Based on the output signal, the control unit 31 can specify the position in the vertical direction when the reference position C (0) of the guide shaft 42 is used as a reference. For example, a position specifying table in which a value corresponding to the magnetic force detected by the magnetic sensor 44 is associated with a distance from the reference position C (0) of the guide shaft 42 is stored in the storage unit 32 (see FIG. 3). . The control part 31 (refer FIG. 3) specifies the position of the up-down direction of the guide shaft 42 corresponding to the value according to magnetic force using a position specification table. The control unit 31 can specify the tension of the ink ribbon 9 based on the specified position of the guide shaft 42 and the spring constant of the spring 45.

<Guide shaft 61>
As shown in FIG. 1, the guide shaft 61 is provided near the lower right corner of the base plate 10A. The guide shaft 61 is cylindrical and extends from the front surface of the base plate 10A toward the front side. The guide shaft 61 is, for example, a roller that can rotate around a rotation shaft extending in the front-rear direction. The ink ribbon 9 contacts a part of the peripheral surface of the guide shaft 61. The transport path R of the ink ribbon 9 extends downward from the guide shaft 42 of the sensor assembly 4, contacts the guide shaft 61, changes its direction, and extends to the left to the thermal head 3 (described later).

<Thermal head 3>
The thermal head 3 is provided in front of the front surface of the base plate 10A in the front-rear direction. Further, the thermal head 3 is provided at a substantially center in the left-right direction of the base plate 10A and below the shafts 21 and 22. The thermal head 3 has a plurality of heating elements arranged linearly in the front-rear direction. The thermal head 3 is adjacent to the transport path R.

  When printing using the printing apparatus 1 is performed, the thermal head 3 is movable in the vertical direction between the printing position 3A and the printing standby position 3B. The printing position 3A is a position where the lower end portion of the thermal head 3 is in contact with a platen roller Q (described later). The print standby position 3B is a position where the lower end portion of the thermal head 3 is separated from the platen roller Q and contacts or approaches the ink ribbon 9 extending in the left-right direction. The thermal head 3 that moves between the printing position 3A and the printing standby position 3B intersects the transport path R of the ink ribbon 9 when the thermal head 3 is disposed at the printing standby position 3B. The motor 83 (see FIG. 3) moves the thermal head 3 in the vertical direction. When the supply roll 9A and the take-up roll 9B are attached to and detached from the ribbon mounting portion 2, the thermal head 3 is moved to a retracted position (not shown) above the print standby position 3B.

  When the thermal head 3 is disposed at the printing position 3A, the transport path R of the ink ribbon 9 extends from the guide shaft 61 toward the left side, contacts the lower end portion of the thermal head 3 and changes its direction, and the guide shaft 62 ( Extends diagonally to the left upward (to be described later).

<Guide shafts 62, 63, 64>
The guide shafts 62, 63, and 64 are each cylindrical and extend from the front surface of the base plate 10A toward the front side. Each of the guide shafts 62, 63, and 64 is, for example, a roller that can rotate around a rotation shaft that extends in the front-rear direction. The guide shaft 62 is on the upper left side of the base plate 10A with respect to the lower end portion of the thermal head 3 disposed at the printing position 3A, in other words, with respect to the lower end portion of the thermal head 3 disposed at the print standby position 3B. It is provided at a position on the lower left side. The guide shaft 63 is provided near the lower left corner of the base plate 10A. The guide shaft 64 is provided near the upper left corner of the base plate 10A.

  The ink ribbon 9 contacts a part of the peripheral surface of each of the guide shafts 62, 63, 64. The transport path R of the ink ribbon 9 extends from the lower end portion of the thermal head 3 disposed at the printing position 3 </ b> A toward the upper left side, contacts the guide shaft 62, changes its direction, and moves to the left side toward the guide shaft 63. Extend. The transport path R of the ink ribbon 9 further changes direction by contacting the guide shaft 63 and extends upward toward the guide shaft 64. The conveyance path R of the ink ribbon 9 further changes its direction by contacting the guide shaft 64 and extends to the lower right side to the winding roll 9B.

<Encoder 64A>
The guide shaft 64 can rotate following the conveyance of the ink ribbon 9 by a frictional force acting between the guide shaft 64 and the ink ribbon 9. The guide shaft 64 is provided with an encoder 64A (see FIG. 3) capable of detecting the number of rotations of the guide shaft 64. The encoder 64A detects the amount of rotation of the guide shaft 64. The encoder 64A outputs a signal indicating the detected rotation amount. The control unit 31 (see FIG. 3) calculates the rotation amount of the guide shaft 64 indicated by the signal output from the encoder 64A and the diameter of the guide shaft 64 stored in the storage unit 32 (see FIG. 3) in advance. It is possible to specify the transport amount of the ink ribbon 9 to the take-up roll 9B wound around the core shaft 90B.

  The control unit 31 may detect the rotation amounts of the motors 81 and 82 and specify the transport amount of the ink ribbon 9 from the rotation amounts of the shafts 21 and 22 that are equal to the rotation amounts of the motors 81 and 82, respectively. For example, the control unit 31 uses the rotation amount of the motor 81 from the reference as a reference when the core shaft 90A of the ribbon assembly 90 is mounted on the shaft 21 and the core shaft 90B is mounted on the shaft 22. 9 may be specified, and the winding amount of the ink ribbon 9 may be specified from the rotation amount of the motor 82 from the reference. And the control part 31 may specify the conveyance amount of the ink ribbon 9 from the specified feeding amount and winding amount.

<Electrical Configuration of Printing Apparatus 1>
The electrical configuration of the printing apparatus 1 will be described with reference to FIG. The printing apparatus 1 includes a control unit 31. The control unit 31 includes a CPU that controls the printing apparatus 1 and various drive circuits that operate according to instructions from the CPU. The various drive circuits include, for example, a circuit for supplying a signal (for example, drive current) to the motor 80, a circuit for supplying a signal (for example, drive current) to the thermal head 3, the sensor assembly 4, and the encoder 64A. Including a circuit for receiving the signal. The control unit 31 is electrically connected to the storage unit 32, the thermal head 3, the sensor assembly 4, the motor 80, the encoder 64A, and the communication interface (communication I / F) 33 via an interface circuit (not shown).

  The storage unit 32 includes various storage media such as a ROM, a RAM, and a flash memory. The storage unit 32 stores a program of processing executed by the control unit 31, print data, a length L of the transport path R, a use stress σu (described later), and a Young's modulus E (described later).

  The thermal head 3 is, for example, a line thermal head having a plurality of heating elements arranged in a line. Each of the plurality of heating elements selectively generates heat according to a signal output from the control unit 31. The motor 80 is a stepping motor that rotates in synchronization with a pulse signal output from the control unit 31. The motor 81 rotates the shaft 21. The motor 82 rotates the shaft 22. The motor 83 moves the thermal head 3 between the print position 3A (see FIG. 1), the print standby position 3B (see FIG. 1), and a retracted position (not shown). The sensor assembly 4 outputs a signal indicating a value corresponding to the position of the guide shaft 42 (see FIG. 1) to the control unit 31. The encoder 64A outputs a signal corresponding to the rotation amount of the guide shaft 64 to the control unit 31.

  The communication I / F 33 is an interface element for performing communication with the external device 100 connected to the printing apparatus 1. The external device 100 is a terminal device used for the user to give various instructions to the printing apparatus 1. The program executed by the control unit 31 may be downloaded from the external device 100 via the communication I / F 72, for example. The control unit 31 may store the program acquired from the external device 100 via the communication I / F 72 in the storage unit 32. Various types of information stored in the storage unit 32 may be changeable via the external device 100.

<Outline of printing operation by printing apparatus 1>
As shown in FIG. 1, the print medium P is conveyed in a predetermined direction D. The printing apparatus 1 has a position where the lower end of the printing apparatus 1 faces the printing surface (upper surface in FIG. 1) of the printing medium P, and a direction in which the direction from the right side to the left side of the printing apparatus 1 coincides with the predetermined direction D. Thus, it is arranged close to the print medium P. A platen roller Q is disposed on the opposite side of the printing apparatus 1 from the printing medium P.

  The printing operation by the printing apparatus 1 is started. The motors 81 and 82 are driven, and the shafts 21 and 22 are rotated. The core shafts 90A and 90B of the ribbon assembly 90 rotate in the forward rotation direction. The ink ribbon 9 is unwound from the supply roll 9 </ b> A of the shaft 21 and taken up by the take-up roll 9 </ b> B of the shaft 22. The ink ribbon 9 is transported to the left side at the portion in contact with the thermal head 3.

  When the transport speed of the ink ribbon 9 increases to the transport speed of the print medium P, the thermal head 3 moves from the print standby position 3B to the print position 3A. The thermal head 3 contacts the platen roller Q from above via the ink ribbon 9 and the print medium P. The ink ribbon 9 is pressed against the printing surface of the printing medium P according to the movement of the thermal head 3. The platen roller Q contacts the surface of the print medium P opposite to the print surface, and presses the ink ribbon 9 and the print medium P against the thermal head 3. The thermal head 3 is heated based on the print data stored in the storage unit 32. The heated portion of the ink ribbon 9 is transferred to the printing surface of the printing medium P. Thereafter, the heating of the thermal head 3 is stopped. The thermal head 3 moves from the printing position 3A to the printing standby position 3B (see FIG. 1). The driving of the motors 81 and 82 is stopped, and the conveyance of the ink ribbon 9 is stopped.

<Characteristics of ink ribbon 9>
If the ink ribbon 9 is slackened in the transport path R during the printing operation, wrinkles may occur in the ink ribbon 9 and the print quality may be reduced. For this reason, tension may be applied to the ink ribbon 9 in order to eliminate the slack of the ink ribbon 9.

A stress corresponding to the magnitude of the applied tension acts on the ink ribbon 9. For example, the stress σ when the tension F is applied to the ink ribbon 9 is derived by the following equation (1). However, the cross-sectional area of the ink ribbon 9 is expressed as “A”. The width of the ink ribbon 9 is expressed as “w”. The thickness of the ink ribbon 9 is expressed as “t”. The thickness t of the ink ribbon 9 substantially matches the thickness of the base film (PET film) of the ink ribbon 9.
σ = F / A = F / (w × t) (1)

  FIG. 4 shows a stress-strain curve of the ink ribbon 9. σy indicates the stress at the yield point S (referred to as “yield stress”). σmax indicates a stress at the time of breaking of the ink ribbon 9 (referred to as “breaking stress”). The slope of the straight line from the origin to the yield point S corresponds to the Young's modulus E. Even if the thickness t changes within an allowable range (for example, about 2 μm to 10 μm) of the thickness t of the ink ribbon 9 used in the ribbon assembly 90 that can be used in the printing apparatus 1, the yield stress σy and the breaking stress σmax and Young's modulus E show substantially the same value.

The stress when the tension Fy (referred to as “yield tension”) is applied to the ink ribbon 9 is the yield stress σy, and the stress when the tension Fmax (referred to as “breaking tension”) is applied to the ink ribbon 9. It is assumed that the breaking stress σmax. In this case, the relationship between the yield tension Fy and the yield stress σy, and the relationship between the breaking tension Fmax and the breaking stress σmax are expressed by the following equations (2) and (3) based on the equation (1), respectively.
Fy = σy × (w × t) (2)
Fmax = σmax × (w × t) (3)

  That is, as the width w and thickness t of the ink ribbon 9 used change, the yield tension Fy and the breaking tension Fmax also change. For example, when the allowable range of the thickness t of the ink ribbon 9 is 2 μm to 10 μm, the maximum value (10 μm) of the allowable range is five times the minimum value (2 μm). In this case, as the thickness t of the ink ribbon 9 changes from the minimum value to the maximum value in the allowable range, the yield tension Fy and the breaking tension Fmax change by a maximum of 5 times.

  The case where the predetermined tension | tensile_strength for eliminating the slack of the ink ribbon 9 is applied to the ink ribbon 9 is illustrated. Here, when the width w and the thickness t of the ink ribbon 9 are indefinite, the control unit 31 cannot determine an appropriate magnitude of tension. For this reason, there is a possibility that the elastic limit is exceeded by applying a tension larger than the yield tension Fy, or the ink ribbon 9 is broken by applying a tension larger than the breaking tension Fmax.

<Determination method of initial tension>
In order to prevent the ink ribbon 9 from exceeding the elastic limit or breaking, the control unit 31 determines the tension applied to the ink ribbon 9 to eliminate the slack as follows. As shown in FIG. 4, a predetermined stress (referred to as “use stress”) σu smaller than the yield stress σy is determined in advance. It is assumed that the stress when the initial tension Fu is applied to the ink ribbon 9 is the use stress σu. In this case, the initial tension Fu is derived from the following equation (4) based on the equation (1).
Fu = σu × (w × t) (4)
Even if the thickness t of the ink ribbon 9 changes within an allowable range, the yield stress σy shows substantially the same value. Therefore, as long as the initial tension Fu satisfies Expression (4), even if the thickness t of the ink ribbon 9 changes within an allowable range, the use stress σu when the initial tension Fu is applied is the yield stress σy and It becomes smaller than the breaking stress σmax. For this reason, the ink ribbon 9 does not exceed the elastic limit or break.

When the initial tension Fu is calculated based on the equation (4), a parameter “w × t” value other than the known use stress σu is required. On the other hand, the elongation amount λ and the tension Fp of the ink ribbon 9 satisfy the relationship of the following equation (5). However, the length of the ink ribbon 9 between the supply roll 9A and the take-up roll 9B, in other words, the length of the transport path R is expressed as “L”.
λ = (L × Fp) / (w × t × E) (5)
Of the above parameters, the length L of the transport path R and the Young's modulus E are known. Therefore, the control unit 31 measures the elongation amount λ and the tension Fp of the ink ribbon 9 in the main process (see FIG. 5) described later, and specifies w × t based on the equation (5). The control unit 31 calculates the initial tension Fu by substituting the specified w × t into the equation (4).

<Main processing>
The main process will be described with reference to FIG. The main process is started when the control unit 31 reads and executes the program stored in the storage unit 32 when the power of the printing apparatus 1 is turned on.

  The control unit 31 measures the diameters of the supply roll 9A and the take-up roll 9B and stores them in the storage unit 32 (S11). The diameters of the supply roll 9A and the take-up roll 9B are necessary when specifying the driving conditions of the motors 81 and 82 for accurately transporting the ink ribbon 9 by the target length. This is because the amount of the ink ribbon 9 that is fed out or wound up from the supply roll 9A changes according to the diameter of the supply roll 9A even when the rotation amount of the shaft 21 is set to a predetermined value. Similarly, the amount of the ink ribbon 9 that is taken up or fed out by the take-up roll 9B varies depending on the diameter of the take-up roll 9B even when the rotation amount of the shaft 22 is a predetermined value.

  The diameters of the supply roll 9A and the take-up roll 9B can be measured by various methods. For example, the control unit 31 rotates the motors 81 and 82 at a predetermined rotational speed by a predetermined number of rotations, and conveys the ink ribbon 9 from the supply roll 9A toward the take-up roll 9B. The control unit 31 acquires a signal output from the encoder 64 </ b> A during the rotation of each of the motors 81 and 82, and specifies the amount of rotation of the guide shaft 64. The control unit 31 divides the rotation amount by time to specify the rotation speed. The control unit 31 specifies the conveyance speed of the ink ribbon 9 based on the known diameter of the guide shaft 64. The controller 31 calculates the diameter of the supply roll 9 </ b> A from the rotation speed of the motor 81 and the conveyance speed of the ink ribbon 9. The controller 31 calculates the diameter of the take-up roll 9B from the rotation speed of the motor 82 and the conveyance speed of the ink ribbon 9. In addition, the measuring method of the diameter of supply roll 9A and winding roll 9B is not limited to said method.

  The controller 31 excites the motor 81 to stop the rotation of the shaft 21 (S13). Thereby, the rotation of the supply roll 9A wound around the core shaft 90A is stopped. The control unit 31 drives the motor 82 so that the core shaft 90B rotates in the forward rotation direction. The rotation of the shaft 22 is started. As a result, the rotation of the take-up roll 9B wound around the core shaft 90B is started, and the ink ribbon 9 is taken up by the take-up roll 9B (S13). The ink ribbon 9 is conveyed from the supply roll 9A toward the take-up roll 9B. Since the rotation of the supply roll 9A is stopped, the ink ribbon 9 is extended.

  The controller 31 rotates the amount of rotation of the shaft 22 (referred to as “first rotation amount”) required to wind the ink ribbon 9 corresponding to the first target amount ga indicating a predetermined length around the take-up roll 9B. It calculates based on the diameter of the winding roll 9B memorize | stored in the memory | storage part 32 by the process of. The control unit 31 acquires a signal output from the sensor assembly 4 when the shaft 22 is rotated by the calculated first rotation amount after the rotation of the shaft 22 is started by the process of S13. The control unit 31 specifies the position of the guide shaft 42 based on the acquired signal. Further, the control unit 31 acquires the tension (referred to as “first tension fa”) of the ink ribbon 9 based on the specified position (S15).

  Based on the signal acquired from the encoder 64A from the time when the rotation of the shaft 22 is started by the process of S13 to the time when the first tension fa is acquired by the process of S15, the control unit 31 performs the guide shaft 64 during this period. Specify the amount of rotation. Further, the control unit 31 acquires the transport amount (referred to as “first transport amount ma”) of the ink ribbon 9 at the position of the guide shaft 64 based on the known diameter of the guide shaft 64 (S17).

  The control unit 31 takes up the ink ribbon 9 corresponding to the second target amount gb indicating the predetermined length conveyed from the reference after the rotation of the shaft 22 is started by the process of S13, that is, to take up the take-up roll 9B. Is calculated based on the diameter of the take-up roll 9 </ b> B stored in the storage unit 32 by the process of S <b> 11. Note that the second target amount gb based on when the rotation of the shaft 22 is started is larger than the first target amount ga, and the second rotation amount is larger than the first rotation amount. The control unit 31 acquires a signal output from the sensor assembly 4 when the shaft 22 is rotated by the calculated second rotation amount after the rotation of the shaft 22 is started by the process of S13. The control unit 31 specifies the position of the guide shaft 42 based on the acquired signal. Further, the control unit 31 acquires the tension of the ink ribbon 9 (referred to as “second tension fb”) based on the specified position (S19). Note that the second tension fb of the ink ribbon 9 obtained at this time is a value different from the first tension fa.

  Based on the signal acquired from the encoder 64A from when the rotation of the shaft 22 is started by the process of S13 until the second tension fb is acquired by the process of S19, the control unit 31 performs the guide shaft 64 during this period. Specify the amount of rotation. Further, the control unit 31 acquires the transport amount (referred to as “second transport amount mb”) of the ink ribbon 9 at the position of the guide shaft 64 based on the known diameter of the guide shaft 64 (S21). Note that the second transport amount mb acquired at this time is a value different from the first transport amount ma. In the present embodiment, the second transport amount mb is larger than the first transport amount ma.

  As shown in FIG. 6, the relationship between the acquired first tension fa (S15), first transport amount ma (S17), second tension fb (S19), and second transport amount mb (S21) is plotted. In this case, each point is arranged on a straight line that passes through the origin and whose inclination is indicated by Young's modulus E.

  In the above description, when the slack amount of the ink ribbon 9 disposed in the portion of the transport path R between the winding roll 9B and the guide shaft 64 is small, the first target amount ga and the first transport amount ma are The second target amount gb and the second transport amount mb match. In this case, the control unit 31 rotates the shaft 22 by the first rotation amount in order to wind the ink ribbon 9 for the first amount (the first target amount ga and the first transport amount ma) around the take-up roll 9B. The first tension fa is acquired (S15). Further, the control unit 31 rotates the shaft 22 by the second rotation amount in order to wind up the ink ribbon 9 corresponding to the second amount (second target amount gb and second transport amount mb) on the take-up roll 9B. The second tension fb is acquired (S19).

  Further, when the shaft 22 is rotated by the first rotation amount after the rotation of the shaft 22 is started by the process of S13, that is, when the first tension fa is acquired (S15), the guide shaft 42 of the sensor assembly 4 is obtained. The first target amount ga is adjusted in advance so that is placed at a position within the movement range C (ab). Similarly, at the time when the shaft 22 is rotated by the second rotation amount after the rotation of the shaft 22 is started by the process of S13, that is, when the second tension fb is acquired (S19), the guide shaft of the sensor assembly 4 is used. The second target amount gb is adjusted in advance so that 42 is arranged at a position within the movement range C (ab).

As shown in FIG. 5, the control unit 31 performs the following calculation to calculate the initial tension Fu (S23). In the equation (5), the control unit 31 substitutes (mb−ma) (see FIG. 6) for λ, and substitutes (fb−fa) (see FIG. 6) for Fp. As a result, the following formula (6) is obtained.
(Mb−ma) = (L × (fb−fa)) / (w × t × E) (6)
The control unit 31 derives Expression (7) by transforming Expression (6).
(W × t) = (L × (fb−fa)) / ((mb−ma) × E) (7)
The control unit 31 substitutes the length L and Young's modulus E stored in the storage unit 32 into Expression (7). Thus, (w × t) is calculated. The control unit 31 further substitutes the use stress σu stored in the storage unit 32 and the calculated (w × t) into the equation (4) to calculate the initial tension Fu.

  The control unit 31 stops the rotation of the motor 82 started by the process of S13. At this time, the ink ribbon 9 is transported by the second transport amount mb acquired by the process of S21 at the position of the guide shaft 64. The control unit 31 rotates the shaft 21 (referred to as “third rotation amount”) required to convey the ink ribbon 9 for the second conveyance amount mb from the take-up roll 9B toward the supply roll 9A. The rotation amount of the shaft 22 (referred to as “fourth rotation amount”) is calculated based on the diameters of the supply roll 9A and the take-up roll 9B stored in the storage unit 32 by the process of S11. The control unit 31 drives the motors 81 and 82 so that the core shaft 90A and the core shaft 90B rotate in the reverse direction. The rotation of the shafts 21 and 22 is started. Thereby, the rotation of the supply roll 9A wound around the core shaft 90A and the take-up roll 9B wound around the core shaft 90B is started. The ink ribbon 9 is unwound from the take-up roll 9B and taken up by the supply roll 9A (S25). The controller 31 stops the rotation of the motors 81 and 82 when the shaft 21 rotates by the calculated third rotation amount and the shaft 22 rotates by the calculated fourth rotation amount. Thus, the ink ribbon 9 is transported by the second transport amount mb from the take-up roll 9B toward the supply roll 9A. As a result, the ink ribbon 9 returns to the state before the main process is started.

  The control unit 31 determines whether an instruction for starting printing is input via the external device 100 (S27). When it is determined that no instruction is input via the external device 100 (S27: NO), the control unit 31 returns the process to S27. When it is determined that the instruction is input via the external device 100 (S27: YES), the control unit 31 advances the process to S29. The controller 31 drives the motors 81 and 82 so that the core shaft 90A and the core shaft 90B rotate in the forward rotation direction. The rotation of the shafts 21 and 22 is started. Thereby, the rotation of the supply roll 9A wound around the core shaft 90A and the take-up roll 9B wound around the core shaft 90B is started. The ink ribbon 9 is fed from the supply roll 9A and wound around the take-up roll 9B, thereby being conveyed from the supply roll 9A toward the take-up roll 9B (S29).

  The control unit 31 acquires a signal output from the sensor assembly 4. The control unit 31 specifies the position of the guide shaft 42 based on the acquired signal, and acquires the tension of the ink ribbon 9 based on the specified position. The control unit 31 feedback-controls the rotation speeds of the motors 81 and 82 so that the acquired tension matches the initial tension Fu calculated by the process of S23. As a result, the tension of the ink ribbon 9 being conveyed is maintained at the initial tension Fu.

  Specifically, it is as follows. The controller 31 decelerates the motor 82 when the specified tension is greater than the initial tension Fu. As a result, the rotation speed of the take-up roll 9B wound around the shaft 22 decreases, and the amount of the ink ribbon 9 taken up by the take-up roll 9B per unit time decreases. As a result, the tension of the ink ribbon 9 is reduced. On the other hand, the control unit 31 accelerates the motor 82 when the specified tension is smaller than the initial tension Fu. As a result, the rotation speed of the take-up roll 9B wound around the shaft 22 increases, and the amount of the ink ribbon 9 taken up by the take-up roll 9B per unit time increases. As a result, the tension of the ink ribbon 9 increases. As described above, the tension of the ink ribbon 9 is maintained at the initial tension Fu.

  The control unit 31 drives the motor 83 to move the thermal head 3 from the print standby position 3B (see FIG. 1) to the print position 3A (see FIG. 1). The control unit 31 performs printing on the print medium P by heating the thermal head 3 based on the print data stored in the storage unit 32 (S31). When printing is completed, the motor 83 is driven to move the thermal head 3 from the printing position 3A (see FIG. 1) to the printing standby position 3B (see FIG. 1). The control unit 31 ends the main process.

<Main functions and effects of this embodiment>
The printing apparatus 1 acquires the first tension fa in the process of transporting the ink ribbon 9 (S15). Further, the printing apparatus 1 acquires a first transport amount ma corresponding to the transport amount of the ink ribbon 9 at the position of the guide shaft 64 and corresponding to the transport amount after starting the rotation of the shaft 22 by the process of S13 ( S17). The printing apparatus 1 further acquires the second tension fb (S19). Further, the printing apparatus 1 obtains the second conveyance amount mb corresponding to the conveyance amount at the position of the guide shaft 64 of the ink ribbon 9 and after the rotation of the shaft 22 is started by the process of S13 ( S21). The printing apparatus 1 calculates (w (width of the ink ribbon 9) × t (thickness of the ink ribbon 9)) by applying the acquired value to Expression (7). The calculated value corresponds to the cross-sectional area of the ink ribbon 9. Further, the stress σ of the ink ribbon 9 is calculated by dividing the tension F acting on the ink ribbon 9 by (w × t) (see Expression (1)). The yield tension Fy and the breaking tension Fmax of the ink ribbon 9 increase in proportion to (w × t) (see equations (2) and (3)). That is, (w × t) can be said to be a parameter indicating resistance to the tension of the ink ribbon 9.

  The printing apparatus 1 substitutes (w × t) calculated based on the acquired first tension fa, second tension fb, first transport amount ma, and second transport amount mb into Expression (4). To do. Thereby, the printing apparatus 1 calculates the initial tension Fu (S23). Since the initial tension Fu is calculated based on the use stress σu smaller than the yield stress σy, even if the initial tension Fu is applied to the ink ribbon 9, the ink ribbon 9 does not exceed the yield limit, and Does not break. For this reason, the printing apparatus 1 applies the specified initial tension Fu to the ink ribbon 9 to prevent the ink ribbon 9 from exceeding the yield limit or to break, and to eliminate the slack of the ink ribbon 9. Can be transported properly. Moreover, the printing apparatus 1 can implement | achieve favorable print quality by performing printing in the state in which the ink ribbon 9 was conveyed appropriately.

  When an instruction for starting printing is input (S27: YES), the printing apparatus 1 starts transporting the ink ribbon 9 (S29). At this time, the printing apparatus 1 performs control so that the tension applied to the ink ribbon 9 becomes the initial tension Fu. Thereby, the slack of the ink ribbon 9 is eliminated. Therefore, the printing apparatus 1 can start printing in a state where the ink ribbon 9 is free of wrinkles, and thus can realize good print quality.

  The printing apparatus 1 acquires the first tension fa and the second tension fb at different timings in the process of transporting the ink ribbon 9 from the supply roll 9A toward the take-up roll 9B (S15, S19). In this case, since the printing apparatus 1 can acquire the first tension fa and the second tension fb by transporting the ink ribbon 9 in the same direction, the transport control of the ink ribbon 9 can be easily performed.

  The printing apparatus 1 drives the motor 82 in a state where the motor 81 is excited to stop the rotation of the shaft 21, and transports the ink ribbon 9 by winding the ink ribbon 9 around the winding roll 9B (S13). In this case, the printing apparatus 1 can accurately calculate (w × t) by acquiring an appropriate elongation amount λ of the ink ribbon 9 and substituting it into Equation (5). For this reason, the printing apparatus 1 can calculate the initial tension Fu for appropriately transporting the ink ribbon 9 with high accuracy.

  The accuracy of the position of the guide shaft 42 specified based on the signal output from the sensor assembly 4 is such that the position of the guide shaft 42 is at both ends (reference position C (0) or maximum position C (m)) of the movement range. The closer you get, the lower it will be. On the other hand, the printing apparatus 1 sets the first target so that the guide shaft 42 of the sensor assembly 4 is disposed at a position within the movement range C (ab) at the time when the first tension fa is acquired (S15). Adjust the amount ga. Similarly, the printing apparatus 1 sets the second target amount so that the guide shaft 42 of the sensor assembly 4 is disposed at a position within the movement range C (ab) at the time when the second tension fb is acquired (S19). Adjust gb. The movement range C (ab) does not include the reference position C (0) and the maximum position C (m). For this reason, since the printing apparatus 1 can specify the position of the guide shaft 42 with high accuracy based on the signal output from the sensor assembly 4, the first tension fa and the second tension fb can be specified with high accuracy.

  Before starting printing, the printing apparatus 1 transports the ink ribbon 9 for the second transport amount mb from the take-up roll 9B toward the supply roll 9A (S25). As a result, the printing apparatus 1 rewinds a part of the ink ribbon 9 that has been conveyed in order to calculate the initial tension Fu of the ink ribbon 9 (the portion corresponding to the second conveyance amount mb), and the ink ribbon 9 is returned to its original state. Return to. Thereafter, when an instruction to start printing is input (S27: YES), printing is performed while the ink ribbon 9 is conveyed from the supply roll 9A toward the take-up roll 9B (S29). Accordingly, the printing apparatus 1 can use a part of the ink ribbon 9 conveyed for calculating the initial tension Fu of the ink ribbon 9 at the time of printing.

<Modification>
The present invention is not limited to the above embodiment, and various modifications can be made. The sensor assembly 4 outputs a signal indicating a value corresponding to the magnetic force detected by the magnetic sensor 44 to the control unit 31. The control unit 31 specifies the position of the guide shaft 42 based on the output signal, and further specifies the tension of the ink ribbon 9 based on the specified position. On the other hand, the sensor assembly 4 may calculate the tension based on the position of the guide shaft 42 and output a signal indicating the calculated tension to the control unit 31. The control unit 31 may directly specify the tension of the ink ribbon 9 based on the signal output from the sensor assembly 4. For example, the sensor assembly 4 may have a tensiometer.

  The control unit 31 may calculate the initial tension Fu by using the first target amount ga instead of the first transport amount ma and using the second target amount gb instead of the second transport amount mb. In this case, the controller 31 does not have to acquire the first transport amount ma and the second transport amount mb. Further, after starting the rotation of the motor 82, the control unit 31 monitors whether the ink ribbon 9 has moved by the first target amount ga at the position of the guide shaft 64 based on the signal output from the encoder 64A. Good. The controller 31 may acquire the first tension fa when it is determined that the motor 82 has rotated by the number of rotations that moves the ink ribbon 9 by the first target amount ga. Similarly, after starting the rotation of the motor 82, the control unit 31 monitors whether the ink ribbon 9 has moved by the second target amount gb at the position of the guide shaft 64 based on the signal output from the encoder 64A. Also good. The controller 31 may acquire the second tension fb when it is determined that the motor 8 has rotated by the number of rotations that moves the ink ribbon 9 by the second target amount gb.

  When an instruction for starting printing is input (S27: YES), the controller 31 starts transporting the ink ribbon 9 (S29). In this case, the control unit 31 acquires the tension of the ink ribbon 9 based on the signal output from the sensor assembly 4, and rotates each of the motors 81 and 82 so that the acquired tension matches the initial tension Fu. The speed was feedback controlled. Here, the control unit 31 may continue the process for controlling the tension of the ink ribbon 9 to the initial tension Fu during the period in which the ink ribbon 9 is conveyed. On the other hand, the control unit 31 may stop the processing for controlling the tension of the ink ribbon 9 to the initial tension Fu after a predetermined time has elapsed since the conveyance of the ink ribbon 9 was started. That is, the control unit 31 may execute a process of controlling the tension of the ink ribbon 9 to the initial tension Fu only when the ink ribbon 9 is transported.

  In the above, the control unit 31 drives the motor 82 in a state where the motor 81 is excited to stop the rotation of the shaft 21, and winds the ink ribbon 9 around the take-up roll 9B (S13). On the other hand, the control unit 31 may drive the motor 82 in a state where the motor 81 is not excited to wind the ink ribbon 9 around the winding roll 9B. Further, the control unit 31 may drive the motor 81 so that the core shaft 90A rotates in the forward rotation direction and feed the ink ribbon 9 from the supply roll 9A. At this time, the motor 81, so that the amount of ink ribbon 9 fed out from the supply roll 9A is smaller than the amount of ink ribbon 9 wound around the take-up roll 9B so that tension acts on the ink ribbon 9. The rotational speed of 82 may be controlled. Furthermore, the control unit 31 first rotates the core shaft 90B in the forward rotation direction, acquires the first tension fa in a state where the ink ribbon 9 is wound around the winding roll 9B (S15), and then the core shaft 90A. The second tension fb may be acquired in a state where the ink ribbon 9 is wound around the supply roll 9A (S19). At this time, the winding amount of the ink ribbon 9 wound around the winding roll 9B when the first tension fa is acquired, and the ink wound around the supply roll 9A when the second tension fb is acquired. It is preferable that the winding amount of the ribbon 9 is different.

  The controller 31 drives the motors 81 and 82 to transport the ink ribbon 9 corresponding to the second transport amount mb from the take-up roll 9B toward the supply roll 9A before an instruction to start printing is input. did. On the other hand, after the instruction to start printing is input, the control unit 31 may transport the ink ribbon 9 for the second transport amount mb from the take-up roll 9B toward the supply roll 9A. Further, the control unit 31 may not execute the process of transporting the ink ribbon 9 for the second transport amount mb from the take-up roll 9B toward the supply roll 9A.

  The control unit 31 calculates (w × t) by substituting (mb−ma) for λ and (fb−fa) for Fp in equation (5). The control unit 31 substituted the use stress σu stored in the storage unit 32 and the calculated (w × t) into the equation (4), and calculated the initial tension Fu. On the other hand, the width w of the ink ribbon 9 to be used may be stored in the storage unit 32 in advance. The controller 31 may calculate the thickness t of the ink ribbon 9 by further substituting the stored width w into the equation (5). The control unit 31 may calculate the initial tension Fu by substituting the calculated thickness t into the equation (4).

  The printing apparatus 1 may have only a configuration for transporting the ink ribbon 9 with respect to the thermal head 3, and may not have the thermal head 3 itself. That is, the printing apparatus 1 may be a transport apparatus that transports the ink ribbon 9 to the external thermal head 3.

  The printing apparatus 1 adjusts the first target amount ga so that the guide shaft 42 of the sensor assembly 4 is disposed at a position within the movement range C (ab) at the time (S15) when the first tension fa is acquired. did. Similarly, the printing apparatus 1 sets the second target amount so that the guide shaft 42 of the sensor assembly 4 is disposed at a position within the movement range C (ab) at the time when the second tension fb is acquired (S19). gb was adjusted. In contrast, the printing apparatus 1 sets the first target amount ga and the second target amount gb so that the guide shaft 42 is disposed at a position between the reference position C (0) and the maximum position C (m). You may adjust.

<Others>
The control unit 31 that performs the process of S13 is an example of the “first transport unit” in the present invention. The sensor assembly 4 is an example of the “tension detector” in the present invention. The magnetic force detected by the magnetic sensor 44 of the sensor assembly 4 is an example of the “parameter according to the tension of the ink ribbon” in the present invention. The guide shaft 42 is an example of the “moving body” in the present invention. The position of the ink ribbon 9 that contacts the guide shaft 64 corresponds to the “predetermined position” of the present invention. The first target amount ga is an example of the “first amount” in the present invention. The second target amount gb is an example of the “second amount” in the present invention. The state before the rotation of the shaft 22 by the process of S13 is an example of the “predetermined state” of the present invention. The control unit 31 that performs the process of S15 is an example of the “first acquisition unit” in the present invention. The control unit 31 that performs the process of S19 is an example of the “second acquisition unit” in the present invention. The control unit 31 that performs the process of S23 is an example of the “determination unit” in the present invention. The shaft 22 is an example of the “first shaft” in the present invention. The shaft 21 is an example of the “second shaft” in the present invention. The control unit 31 that performs the process of S29 is an example of the “second transport unit” in the present invention. The control unit 31 that performs the process of S25 is an example of the “third transport unit” in the present invention. The control unit 31 that performs the process of S31 is an example of the “printing unit” in the present invention. The process of S13 is an example of the “first transport step” in the present invention. The process of S15 is an example of the “first acquisition step” in the present invention. The process of S19 is an example of the “second acquisition step” in the present invention. The process of S23 is an example of the “decision step” in the present invention.

1: Printer 3: Thermal head 4: Sensor assembly 9: Ink ribbon 9A: Supply roll 9B: Winding rolls 21, 22: Shaft

Claims (9)

First conveying means for rotating at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted, and transporting the ink ribbon between the ribbon rolls mounted on the respective shafts;
A tension detection unit that detects a parameter according to the tension of the ink ribbon conveyed between the ribbon rolls;
Based on a parameter detected by the tension detection unit when the ink ribbon is transported by the first transport means so that the transport amount of the mounted ink ribbon from a predetermined state becomes a first amount. First acquisition means for acquiring one tension;
Based on the parameter detected by the tension detection unit when the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the second amount by the first transport unit, A second acquisition means for acquiring a second tension;
From the respective values of the first tension when the ink ribbon is transported by the first amount and the second tension when the ink ribbon is transported by the second amount, the initial tension of the ink ribbon is determined. A decision means to decide;
A conveying apparatus comprising:   The transport apparatus according to claim 1, further comprising a second transport unit that starts transport of the ink ribbon by applying the initial tension determined by the determination unit to the ink ribbon. The first conveying means rotates the first shaft of the two shafts, winds the ink ribbon around a winding roll that is the ribbon roll attached to the first shaft,
The first acquisition means acquires the first tension when the first shaft is rotated by an amount of rotation by which the first ribbon is wound around the take-up roll by the first amount by the first conveying means. And
When the second acquisition unit rotates the first shaft by the rotation amount that causes the ink ribbon to be wound on the winding roll by the second amount larger than the first amount by the first conveying unit. The conveying device according to claim 1, wherein the second tension is acquired. The first transport means includes
Of the two shafts, the winding roll is rotated in a state in which the rotation of the supply roll, which is the ribbon roll mounted on the second shaft different from the first shaft, is stopped, and the winding roll The transport apparatus according to claim 3, wherein the ink ribbon is transported toward a take-up roll. The tension detector
Detecting the tension by detecting the position of a moving body that moves according to the tension of the ink ribbon conveyed between the ribbon rolls;
The first acquisition unit and the second acquisition unit are respectively
5. The transport device according to claim 1, wherein the tension is acquired in a state where the moving body of the tension detection unit is disposed at a position within a predetermined movement range. The first conveying means rotates the first shaft of the two shafts, winds the ink ribbon around a take-up roll which is the ribbon roll mounted on the first shaft, and the two shafts From the supply roll that is the ribbon roll mounted on the second shaft different from the first shaft, the ink ribbon is conveyed toward the take-up roll,
After the initial tension is determined by the determining means, the ink ribbon corresponding to the transport amount of the ink ribbon wound around the take-up roll by the first transport means is transferred from the take-up roll to the supply roll. A third conveying means for conveying toward the
The second conveying means includes
3. The ink ribbon is transported from the supply roll toward the take-up roll in a state where the initial tension is applied after the ink ribbon is transported by the third transport unit. The conveying apparatus as described in. The transport apparatus according to any one of claims 1 to 6,
A printing apparatus comprising: a printing unit that performs printing on the ink ribbon conveyed by the conveyance apparatus. A first transporting step of rotating at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted and transporting the ink ribbon between the ribbon rolls mounted on the respective shafts;
Based on the parameter detected by the tension detection unit when the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the first amount by the first transporting step, A first acquisition step of acquiring tension;
Based on the parameter detected by the tension detection unit when the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the second amount by the first transport step, A second acquisition step of acquiring a second tension;
From the respective values of the first tension when the ink ribbon is transported by the first amount and the second tension when the ink ribbon is transported by the second amount, the initial tension of the ink ribbon is determined. A decision step to decide;
A conveying method characterized by comprising: A first transporting step of rotating at least one of two shafts on which a ribbon roll around which an ink ribbon is wound is mounted and transporting the ink ribbon between the ribbon rolls mounted on the respective shafts;
Based on the parameter detected by the tension detection unit when the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the first amount by the first transporting step, A first acquisition step of acquiring tension;
Based on the parameter detected by the tension detection unit when the ink ribbon is transported so that the transport amount from the predetermined state of the mounted ink ribbon becomes the second amount by the first transport step, A second acquisition step of acquiring a second tension;
From the respective values of the first tension when the ink ribbon is transported by the first amount and the second tension when the ink ribbon is transported by the second amount, the initial tension of the ink ribbon is determined. A decision step to decide;
Is a conveyance program for causing a computer of the conveyance apparatus to execute the above.

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