JP2006305852A - Thermal transfer printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermal transfer printer which can detect a ribbon end as soon as an ink ribbon runs out. <P>SOLUTION: This thermal transfer printer detects the presence or absence of a tension which is imparted to the ink ribbon 4 by using a movable member 13 and an end sensor 14, functioning as a ribbon end detecting means. When the tension of the ink ribbon 4 is lost, the thermal transfer printer detects that the ink ribbon 4 held by a ribbon feeding shaft runs out. Thus, the ribbon end can be detected on the basis of the tension of the ink ribbon 4, which extinguishes as soon as the ink ribbon 4 held by the ribbon feeding shaft 5 runs out. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a thermal transfer printer that performs printing by sandwiching and transporting a printing medium such as a label and an ink ribbon between a thermal head and a platen roller, and more particularly to a thermal transfer printer that detects a ribbon end and stops a printing operation.

  A general thermal transfer printer sandwiches and conveys a printing medium such as a label and an ink ribbon between a thermal head and a platen roller, and selectively heats a heating element of the thermal head, thereby printing the printing surface of the printing medium. Ink is transferred from the ink ribbon. The ink ribbon is mounted on a ribbon supply shaft while being wound in a roll shape, and is supplied from the ribbon supply shaft between the thermal head and the platen roller. The thermal head and the platen roller synchronize the ink with the print medium. The ribbon is also nipped and conveyed, and the ink ribbon after printing is wound around the ribbon winding shaft.

  In such a thermal transfer printer, when the ink ribbon is exhausted, printing on the printing medium cannot be performed. Therefore, it is necessary to stop the printing operation by detecting the end of the ink ribbon, that is, the ribbon end. As a ribbon end detection method, an optical sensor is used to detect the presence or absence of an ink ribbon in the travel path (see, for example, Patent Document 1), and the cumulative number of pulses from a rotary encoder that rotates integrally with the ribbon supply shaft. There is a method of detecting the ribbon end based on the preset number of end definition pulses corresponding to the total length of the ink ribbon (see, for example, Patent Document 2). When a rotary encoder that rotates integrally with the ribbon supply shaft is used, the ribbon end can be detected when the rotation of the ribbon supply shaft stops and the pulse output from the rotary encoder disappears.

  However, when detecting the presence or absence of an ink ribbon in the traveling path using an optical sensor as in the prior art, it is necessary to adjust the gap between the optical sensor and the ink ribbon, and the ink traveling There is a problem in that the ribbon end comes into contact with the optical sensor, so that the ink adheres to the optical sensor and the ribbon end cannot be detected.

  In addition, when the ribbon end is detected based on the cumulative number of pulses from the rotary encoder that rotates integrally with the ribbon supply shaft and the number of end definition pulses set in advance corresponding to the total length of the ink ribbon, the ink ribbon is detected in advance. Therefore, there is a problem that the initial setting is troublesome.

In addition, when detecting the ribbon end due to the absence of pulse output from the rotary encoder, the ink ribbon is usually used because a back tension mechanism is provided on the ribbon supply shaft to apply tension to the ink ribbon. At that moment, the ribbon supply shaft is rotated in the reverse direction by the back tension mechanism, and it takes time until the ribbon supply shaft stops. Therefore, in the thermal transfer printer capable of high-speed printing, the end of the ink ribbon reaches the thermal head between the time when the ink ribbon runs out and the time when the ribbon end from which the pulse output from the rotary encoder is lost is detected. There was a problem that defective printing occurred.
JP 2004-167890 A JP 2001-47717 A

  The present invention has been made in view of such problems, and an object of the present invention is to require an optical sensor for detecting the presence or absence of an ink ribbon in the traveling path and input of the full length data of the ink ribbon in advance. Therefore, it is an object to provide a thermal transfer printer that can detect the ribbon end at the moment when the ink ribbon runs out.

In order to solve the above problems, the present invention has the following configurations.
The gist of the invention described in claim 1 is a thermal transfer in which printing is performed by sandwiching and transporting an ink ribbon and a printing medium spanned between a ribbon supply shaft and a ribbon take-up shaft between a thermal head and a platen roller. A ribbon end that detects the presence or absence of tension applied to the ink ribbon and detects that the ink ribbon held on the ribbon supply shaft is exhausted when the tension of the ink ribbon is lost It exists in the thermal transfer printer characterized by comprising a detection means.
The invention according to claim 2 is characterized in that the ribbon end detecting means detects the presence or absence of tension of the ink ribbon between the ribbon supply shaft and the platen roller. Exists in thermal transfer printers.
According to a third aspect of the present invention, the ribbon end detection means includes: a movable member that moves according to the presence or absence of tension applied to the ink ribbon; and an end detection sensor that detects the movement of the movable member. The thermal transfer printer according to claim 1 or 2, wherein

  The thermal transfer printer of the present invention is configured to detect the presence or absence of tension applied to the ink ribbon, and to detect that the ink ribbon held on the ribbon supply shaft is exhausted when the tension of the ink ribbon is lost. This makes it possible to detect the ribbon end based on the tension of the ink ribbon that disappears as soon as the ink ribbon held on the ribbon supply shaft runs out, so that an optical sensor that detects the presence or absence of the ink ribbon in the traveling path, There is an effect that the ribbon end can be detected at the moment when the ink ribbon runs out without requiring the input of the full length data of the ink ribbon in advance.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic side view showing a configuration of an embodiment of a thermal transfer printer according to the present invention, and FIG. 2 is a block diagram showing a schematic configuration of a control system of an embodiment of the thermal transfer printer according to the present invention. 3 is a front view showing the configuration of the movable member shown in FIG. 1, and FIG. 4 is a perspective view showing the configuration of the end detection sensor shown in FIG.

  In this embodiment, referring to FIG. 1, a platen roller 1 and a thermal head 2 having a heating element formed on a surface facing the platen roller 1, a printing medium 3 such as a label, and an ink ribbon 4 is sandwiched between the platen roller 1 and the thermal head 2 and the heating element of the thermal head 2 is selectively heated to transfer the ink from the ink ribbon 4 to the printing surface of the medium 3 to be printed. Desired characters, barcodes and the like are printed.

  The ink ribbon 4 is bridged between the ribbon supply shaft 5 and the ribbon take-up shaft 6. The ink ribbon 4 held in a state of being wound around the ribbon supply shaft 5 is supplied between the platen roller 1 and the thermal head 2, and the transferred ink ribbon 4 is rotatably provided. It reaches the ribbon take-up shaft 6 via the turning roller 7 and is taken up by the ribbon take-up shaft 6.

  Referring to FIG. 2, a platen drive motor 9 that rotationally drives the platen roller 1 and a winding drive motor 10 that rotationally drives the ribbon winding shaft 6 are controlled by a print control unit 11. The printing medium 3 is printed by controlling the platen driving motor 9 and the winding driving motor 10 to selectively generate heat from the heating element of the thermal head 2 while running the printing medium 3 and the ink ribbon 4.

  The traveling speed of the ink ribbon 4 wound on the ribbon winding shaft 6 is set to exceed the traveling speed of the printing medium 3 conveyed by the platen roller 1 so as not to loosen the ink ribbon 4. The difference in running speed between the ink ribbon 4 and the printing medium 3 is configured to be absorbed by providing the ribbon take-up shaft 6 with a torque limiter 8 as a slip mechanism.

  The ribbon supply shaft 5 is provided with a back tension mechanism 12 that applies a back tension to the ink ribbon 4. The back tension mechanism 12 is a mechanism that urges the ribbon supply shaft 5 in a direction opposite to the feeding direction of the ink ribbon 4 with a spring or the like, and applies a predetermined tension to the ink ribbon 4.

  In the traveling path of the ink ribbon 4 between the ribbon supply shaft 5 and the platen roller 1, a movable member 13 that functions as a ribbon end detection unit that detects a ribbon end depending on whether the ink ribbon 4 is tensioned, an end detection sensor 14, Is provided. Referring to FIG. 3, the movable member 13 is a plate-like member that moves according to the presence or absence of the tension of the ink ribbon 4, and the ribbon supply shaft 5 and the ribbon take-up are set so that the longitudinal direction is the width direction of the ink ribbon 4. A pair of guide plates 15 to which the shaft 6 is attached are movably installed, and are urged by a spring 16 in a direction to push the ink ribbon 4.

  In a state in which the ink ribbon 4 is stretched between the ribbon supply shaft 5 and the ribbon take-up shaft 6 and tension is applied to the ink ribbon 4 by the back tension mechanism 12, the movable member 13 is moved as shown in FIG. As shown in FIG. 4, the detection end 17 formed at one end of the movable member 13 is urged in the direction against the urging force of the spring 16 by the ink ribbon 4 as shown in FIG. 14 is arranged at a position detected by 14. As the end detection sensor 14, for example, an optical sensor that optically detects the presence / absence of the detection end 17 can be used, or a magnetic sensor that magnetically detects the presence / absence of the detection end 17 can be used.

  When the ink ribbon 4 held on the ribbon supply shaft 5 disappears and the end of the ink ribbon 4 is released from the ribbon supply shaft 5, the tension on the ink ribbon 4 acting on the movable member 13 disappears, and the movable member 13 As shown in FIG. 3B, the detection end 17 formed at one end of the movable member 13 is not detected by the end detection sensor 14 as shown in FIG. The ribbon end signal is output from the end detection sensor 14.

  2, the ribbon end signal from the end detection sensor 14 is configured to be input to the print control unit 11. When the ribbon end signal is input, the print control unit 11 receives the platen drive motor. 9 and the winding drive motor 10 are stopped to stop the printing operation, and ribbon end processing such as displaying an ink ribbon out warning on a display unit (not shown) is executed.

  As described above, according to the present embodiment, the presence or absence of the tension applied to the ink ribbon 4 is detected by the movable member 13 that functions as a ribbon end detection unit and the end detection sensor 14, and the tension of the ink ribbon 4 is detected. If the ink ribbon 4 held on the ribbon supply shaft 5 disappears, the ink ribbon 4 that disappears at the same time that the ink ribbon 4 held on the ribbon supply shaft 5 runs out is detected. Since the ribbon end can be detected based on the tension of the ink ribbon 4, the ink ribbon 4 can be detected without requiring an optical sensor for detecting the presence or absence of the ink ribbon 4 in the traveling path or the input of the full length data of the ink ribbon in advance. There is an effect that the ribbon end can be detected at the moment when there is no more.

  In the present embodiment, the movable member 13 is a plate-like member, but the shape of the movable member 13 is not particularly limited. For example, a guide roller for guiding the travel of the ink ribbon 4 is used as the movable member 13. be able to.

  Note that the present invention is not limited to the above-described embodiments, and it is obvious that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. In addition, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, and can be set to a suitable number, position, shape, and the like in practicing the present invention. In each figure, the same numerals are given to the same component.

1 is a schematic side view showing a configuration of an embodiment of a thermal transfer printer according to the present invention. It is a block diagram which shows schematic structure of the control system of embodiment of the thermal transfer printer which concerns on this invention. It is a front view which shows the structure of the movable member shown in FIG. It is a perspective view which shows the structure of the end detection sensor shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Platen roller 2 Thermal head 3 Medium to be printed 4 Ink ribbon 5 Ribbon supply shaft 6 Ribbon take-up shaft 7 Turning roller 8 Torque limiter 9 Platen drive motor 10 Take-up drive motor 11 Print controller 12 Back tension mechanism 13 Movable member (ribbon) End detection means)
14 End detection sensor (ribbon end detection means)
15 Guide plate 16 Spring 17 Detection end

Claims (3)

A thermal transfer printer that performs printing by sandwiching and transporting an ink ribbon and a printing medium spanned between a ribbon supply shaft and a ribbon take-up shaft between a thermal head and a platen roller,
Ribbon end detection means for detecting the presence or absence of tension applied to the ink ribbon and detecting that the ink ribbon held on the ribbon supply shaft is exhausted when the tension of the ink ribbon is exhausted. A thermal transfer printer characterized by that.   2. The thermal transfer printer according to claim 1, wherein the ribbon end detecting means detects the presence or absence of tension of the ink ribbon between the ribbon supply shaft and the platen roller. The ribbon end detection means includes a movable member that moves according to the presence or absence of tension applied to the ink ribbon;
3. The thermal transfer printer according to claim 1, further comprising an end detection sensor for detecting movement of the movable member.

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