JP4208986B2 - Ribbon tension device for printer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a ribbon tensioning device in a printer that can prevent wrinkles generated on a carbon ribbon in a thermal transfer printer.
[0002]
[Prior art]
Conventionally, for example, printers as shown in FIGS. 6 and 7 are known.
[0003]
FIG. 6 mainly shows a printer 2 for thermal transfer, which has a ribbon supply shaft 6 for a ribbon (carbon ribbon) 4, a printing mechanism 8, a rotation drive mechanism 10, and a ribbon take-up shaft 12.
[0004]
The printing mechanism 8 has a platen roller 14 and a thermal head 16, and the platen roller 14 is driven to rotate in both the forward and reverse directions.
[0005]
The rotational drive mechanism 10 includes a drive motor 18, and both the platen roller 14 and the ribbon take-up shaft 12 are rotationally driven by the rotational drive of the pulsating motor 18. That is, a first belt 20 is installed between the drive motor 18 and the platen roller 14, and a second belt 22 is installed between the platen roller 14 and the ribbon take-up shaft 12. When the motor 18 is driven, the platen roller 14 rotates via the first belt 20 and the ribbon take-up shaft 12 rotates in the same direction as the rotation direction of the platen roller 14 via the second belt 22. It is.
[0006]
As shown in FIG. 7, a pulley 28 with a one-way clutch 26 and a frictional resistor 30 are attached to the ribbon take-up shaft 12. The one-way clutch 26 engages in the direction F for winding the carbon ribbon 4 to freely rotate the ribbon take-up shaft 12, and engages with the ribbon take-up shaft 12 in the direction B opposite to the take-up. The combined state is canceled and the ribbon winding shaft 12 is controlled so as not to rotate, that is, in a so-called free state.
[0007]
Further, the frictional resistor 30 is made of, for example, a felt plate, and prevents the ribbon winding shaft 12 from rotating more than necessary due to the pressing pressure including the frictional force of the felt. Reference numeral 32 denotes a machine frame.
[0008]
When printing is performed by such a printer 2, a belt-like print medium 24 such as a carbon ribbon 4 and a label or a tag is sandwiched between the thermal head 16 and the platen roller 14 of the printing mechanism 8, and the platen roller 14. , The carbon ribbon 4 and the print medium 24 are conveyed in the conveyance direction F, and predetermined information is printed on the print medium 24. At this time, the pulley 28 rotates via the second belt 22 installed between the platen roller 14 and the one-way clutch 26 driven by the rotation of the pulley 28 takes up the ribbon take-up shaft 12 in the direction F. And the carbon ribbon 4 is wound around the ribbon winding shaft 12.
Further, after printing, in order to position the printing medium 24 at a predetermined printing position, the platen roller 14 is back-fed, and in conjunction with this, the carbon ribbon 4 is also back-fed, that is, in the reverse winding direction. Pulled by B.
[0009]
By the way, since the one-way clutch 26 fitted to the ribbon take-up shaft 12 is in a free state, the carbon ribbon 4 taken up by the ribbon take-up shaft 12 at the time of back feed of the print medium 24 is in the platen roller 14. However, backfeeding may occur more than necessary due to the influence of the second belt 22 and the one-way clutch 26 interposed between the platen roller 14 and the platen roller 14. That is, the one-way clutch 26 and the ribbon take-up shaft 12 are in contact with each other, so that frictional resistance acts and a complete free state is not achieved. Therefore, the belt accompanying rotation of the platen roller 14 in the back feed direction B is not achieved. The tension (inertial force) 22 is transmitted to the ribbon take-up shaft 12 via the pulley 28 and the one-way clutch 26, and the carbon ribbon 4 may be fed back more than necessary. If the carbon ribbon 4 is excessively back-fed, wrinkles are likely to occur. Therefore, the tension of the belt 22 is controlled so that the tension of the belt 22 is not easily transmitted to the ribbon take-up shaft 12 by the pressing force of the frictional resistor 30, and the wrinkles are controlled. To prevent the occurrence of
[0010]
However, in such a conventional ribbon tensioning apparatus, the frictional force of the belt 22 is prevented from being transmitted to the ribbon take-up shaft 12 by the pressing pressure including the frictional force. Since the felt (not shown) forming the frictional resistor 30 is easily worn away, the durability is not stable.
[0011]
[Problems to be solved by the invention]
The present invention has been made paying attention to the above-described problems, and provides a ribbon tensioning device in a printer that can stably rotate the ribbon take-up shaft with a simple structure and is less likely to wrinkle the ribbon. Is an issue.
[0012]
[Means for Solving the Problems]
The present invention made to solve the above problems is a printer that performs printing on a print medium via a ribbon by a thermal head, and is mounted on the ribbon winding shaft for winding the ribbon, and the ribbon winding shaft, The ribbon winding shaft is engaged with the ribbon winding shaft in the ribbon winding direction to rotate the ribbon winding shaft, and the engagement state with the ribbon winding shaft is released in the reverse direction of the ribbon winding. The rotation control means and the ribbon take-up shaft are attached to the ribbon take-up shaft, the engagement state with the ribbon take-up shaft is released in the ribbon take-up direction, and the ribbon take-up shaft is against rotation in the reverse direction of the ribbon take-up. And a second rotation control means having an elastic body that urges the ribbon in the winding direction of the ribbon.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of a ribbon tensioning apparatus in a printer according to an embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to a prior art example, and this is abbreviate | omitted for detailed description.
[0014]
FIG. 1 is a partially enlarged front view of a ribbon tensioning device 40. The ribbon tensioning device 40 mainly includes a ribbon take-up shaft 42, a first rotation control means 44, a second rotation control means 46, and a first rotation control means 46. The frictional resistance body 48 and the second frictional resistance body 50 are provided.
[0015]
The first rotation control means 44 includes a one-way clutch 54 having a pulley 52 and is fitted on the ribbon take-up shaft 42. The pulley 52 is connected to the platen roller 14 via the second belt 22, and the rotation of the platen roller 14 is transmitted to the rotation control means 44. The one-way clutch 54 is engaged in the winding direction F of the carbon ribbon 4 and rotates the ribbon winding shaft 42, but in the winding reverse direction B, the engaged state is released and becomes a free state. Power is not transmitted to the take-up shaft 42.
[0016]
The second rotation control means 46 includes a one-way clutch 56 and an elastic body 58 made of, for example, a coil spring. The one-way clutch 56 is fitted to the ribbon take-up shaft 42 and is engaged with the ribbon take-up shaft 42 in the reverse direction B of the carbon ribbon 4 but is free in the direction F in which the carbon ribbon 4 is taken up. It is said. One end of the elastic body 58 is fixed to the one-way clutch 56 fitted to the ribbon winding shaft 42, and the other end is fixed to the machine frame 32, and the one-way clutch 56 is wound in the direction of winding the carbon ribbon 4. Is energized.
[0017]
The state of the ribbon take-up shaft 42 when it is conveyed while printing on the print medium 24 by the printer having the ribbon tensioning device 40 will be described mainly with reference to FIG. In conjunction, power is transmitted to the one-way clutch 54 of the first rotation control means 44 via the second belt 22 and the pulley 52. The one-way clutch 54 fitted to the ribbon take-up shaft 42 is locked in the direction F for taking up the carbon ribbon 4 and rotates the ribbon take-up shaft 42. The carbon ribbon 4 is wound on the ribbon winding shaft 42. At this time, the one-way clutch 56 of the second rotation control means 46 fitted to the ribbon take-up shaft 42 is in a free state and therefore does not transmit power to the ribbon take-up shaft 42.
[0018]
Next, the state of the ribbon take-up shaft 42 when the print medium 24 is back-fed will be described with reference to FIG. When the platen roller 14 is rotated in the reverse direction for back feeding, power is transmitted to the one-way clutch 54 of the first rotation control means 44 via the second belt 22 and the pulley 52 in conjunction with the rotation of the platen roller 14. Try to tell. However, since the one-way clutch 54 is free in the reverse direction B of the winding of the carbon ribbon 4, no power is transmitted to the ribbon winding shaft 42.
[0019]
At this time, even if the tension (inertial force) of the second belt 22 is transmitted to the ribbon take-up shaft 42 via the one-way clutch 54, the second rotation control means 46 fitted to the ribbon take-up shaft 42 is used. Since the one-way clutch 56 urges the ribbon take-up shaft 42 in the direction F for taking up the carbon ribbon 4 by the coil spring 58, the carbon ribbon 4 can be kept in the take-up state without loosening.
[0020]
FIG. 4 is a schematic perspective view of the first frictional resistor 48. The frictional resistor 48 mainly includes a first guide plate 60, a hold plate 62, a lining 64, and a second guide plate 66. The surface of the lining 64 on the second guide plate 66 side is a friction surface. It has become. The friction resistor 48 has the entire friction resistor 48 on the base side of the ribbon take-up shaft 42 in a state where the hold plate 62 and the lining 64 are sandwiched between the first guide plate 60 and the second guide plate 66. The ribbon winding shaft 42 is arranged so as to be pressed against the ribbon winding shaft 42 so as to prevent excessive rotation of the ribbon winding shaft 42.
[0021]
FIG. 5 is a schematic perspective view of the second frictional resistor 50. The frictional resistor 50 mainly includes a washer 68, a disk 70, a spring 72, a stopper collar 74, an adjusting screw 76, and a stopping screw 78, and is attached to the leading end portion of the ribbon take-up shaft 42. A friction surface is formed between the washer 68 and the disk 70, and the pressure is adjusted by the adjustment screw 76 and set so as to be pressed against the ribbon take-up shaft 42 side. This is intended to prevent excessive rotation of the ribbon take-up shaft 42.
[0022]
By sandwiching the ribbon take-up shaft 42 from both sides by the second friction resistor 50 and the first friction resistor 48, a synergistic effect with the first and second rotation control means 44 and 46 is achieved. The excessive rotation of the ribbon take-up shaft 42 can be further prevented, so that wrinkles of the carbon ribbon 4 can be reliably prevented.
[0023]
【The invention's effect】
In the present invention, as described above, the second rotation having the first rotation control means for rotating the ribbon winding shaft in the ribbon winding direction and the elastic body biased in the ribbon winding direction. By providing the control means, it is possible to prevent excessive rotation of the ribbon take-up shaft even during backfeeding, and as a result, the ribbon is less likely to wrinkle.
[Brief description of the drawings]
FIG. 1 is a partially enlarged front view in which a part of a printer provided with a ribbon tensioning device according to the present invention is enlarged. FIG. 2 is an operation explanatory view of first and second rotation control means when feeding a print medium. 3 is an operation explanatory view of the first and second rotation control means at the time of printing medium back feed. FIG. 4 is a perspective view of the first friction resistor. FIG. 5 is a second friction resistor. FIG. 6 is a schematic side view of a conventional printer. FIG. 7 is a front view as seen from the direction of arrow VII in FIG.
F Ribbon winding direction (conveyance direction)
B Reverse winding direction of ribbon (back feed direction)
2 Printer (conventional)
4 Carbon ribbon (ribbon)
6 Ribbon supply shaft 8 Printing mechanism 10 Rotation drive mechanism 12 Ribbon take-up shaft 14 Platen roller 16 Thermal head 18 Drive motor 20 First belt 22 Second belt 24 Print medium 26 One-way clutch 28 Pulley 30 Friction resistor 32 Machine frame 40 Ribbon tension device 42 Ribbon take-up shaft 44 First rotation control means 46 Second rotation control means 48 First friction resistor 50 Second friction resistor 52 Pulley (first rotation control means)
54 One-way clutch (first rotation control means)
56 One-way clutch (second rotation control means)
58 Elastic body (coil spring, second rotation control means)
60 First guide plate 62 Hold plate 64 Lining 66 Second guide plate 68 Washer 70 Disc 72 Spring 74 Stopper collar 76 Adjustment screw 78 Stop screw

Claims (1)

In a printer that prints on a print medium via a ribbon with a thermal head,
A ribbon winding shaft for winding the ribbon;
The ribbon winding shaft is attached to the ribbon winding shaft so that the ribbon winding shaft is engaged with the ribbon winding shaft to rotate the ribbon winding shaft, and the ribbon winding shaft is rotated in the reverse direction of the ribbon winding. First rotation control means for releasing the combined state;
Mounted on the ribbon winding shaft, the engagement state with the ribbon winding shaft is released in the ribbon winding direction, and the ribbon winding shaft is taken up against the rotation in the reverse direction of the ribbon winding. Second rotation control means having an elastic body biased in the direction;
A ribbon tensioning device for a printer, comprising:

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