JPH0655530B2 - Thermal transfer printer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermal transfer printer that prints images and the like.

[Prior Art] As one of thermal transfer printers, there is a thermal transfer color printer that performs color printing by appropriately thermally transferring a plurality of color inks applied to an ink film onto printing paper.

As such a thermal transfer type color printer, those shown in FIGS. 3 to 5 have been conventionally known.

In FIG. 3, reference numeral 1 is a printer body. On the back surface of the printer body 1, a printing paper supply roll 3 on which a printing paper 2 is wound is rotatably supported by a bracket 1a. As shown in FIG. 4, the printing paper 2 has feed holes 2a, 2a, ...
A large number of printing papers 2 are formed in a straight line in the longitudinal direction (vertical direction in the drawing) of the printing paper 2, and the portion pulled out from the printing paper supply roll 3 is inside the printer body 1 as shown in FIG. It is wound around the guide roller 4 and the platen roller 5 provided on the printer main body 1, and then pulled out to the outside from the vicinity of the center of the upper surface of the printer body 1. The guide roller 4 and the platen roller 5 are provided for feeding the printing paper 2, and sprocket pins 4a, 4a having a diameter smaller than the feed holes 2a, 2a of the printing paper 2 are provided at both ends of the outer peripheral surface thereof. .., 5a, 5a .. are formed at equal pitches, and these sprocket pins 4a, 4a
.. are engaged with the feed holes 2a, 2a of the printing paper 2 (see FIG. 4). And
The shaft end of the platen roller 5 is connected to a motor (not shown) so as to rotate in the normal direction (in the direction of arrow Y1 in the figure) about the axis.
It can be reversed (in the direction of arrow Y2 in the drawing), and this rotation is also transmitted to the guide roller 4 by a belt (not shown). The belt is wound so that the guide roller 4 and the platen roller 5 have the same peripheral speed and the rotating directions thereof are opposite to each other.

On the other hand, below the guide roller 4, the ink film 6
An ink film supply roll 7 on which is wound is rotatably attached. The ink film 6 is formed by repeatedly applying the yellow, magenta, and cyan color inks, which are the primary colors for color surface image printing, sequentially in the longitudinal direction thereof as shown in FIG. 5, and is shown in FIG. As described above, the portion pulled out from the ink film supply roll 7 is wound around the outside of the printing paper 2 wound around the platen roller 5, further wound around the guide roller 8, and then wound around the take-up roll 9. Has been wound up. The take-up roll 9 is driven by a motor (not shown).

A thermal head 10 is provided below the platen roller 5. This thermal head 10
Is provided so as to be capable of being brought into pressure contact with and separated from the outer peripheral surface of the platen roller 5, and when the ink film 6 wound around the outer periphery of the platen roller 5 with the printing paper 2 sandwiched therebetween is subjected to a heat pulse to the ink film 6. The color ink applied and applied to the ink film 6 is thermally transferred to the printing paper 2.

In the thermal transfer type color printer having the above configuration, color printing is performed according to the following procedure.

First, the platen roller 5 is rotated forward (in the direction of the arrow Y1 in the figure).
Then, the print start position of the printing paper 2 is set to the thermal head 10
And the winding roll 9 is rotated to match the tip position of the yellow color ink applied to the ink film 6 with the printing position of the thermal head 10. Next, the thermal head 10 is brought into pressure contact with the ink film 6 wrapped around the outer peripheral surface of the platen roller 5 with the printing paper 2 sandwiched therebetween. Then, the platen roller 5 is rotated in the forward direction to send the printing paper 2 to the paper discharge side in a state where the ink films 6 are superposed on each other, and a heat pulse is appropriately applied to the thermal head 10 so that the yellow color ink is printed. Heat transfer to.

As described above, when the printing of the yellow is completed, the thermal head 10 is separated from the ink film 6, and then the platen roller 5 is normally rotated again to separate the printing paper 2 and the ink film 6. Next, the platen roller 5 is rotated in the reverse direction (arrow Y2 direction in the drawing) to feed the printing paper 2 to the paper supply side (right side in the drawing), and the printing start position of the printing paper 2 is returned to the printing position of the thermal head 10. , Rotate the take-up roll 9 slightly in the direction of the arrow Y3 in the figure,
The tip portion of the magenta color ink applied to the ink film 6 is made to coincide with the printing position of the thermal head 10. Then, as in the case of the yellow, the thermal head 10 is brought into pressure contact with the ink film 6 and the platen roller 5 is normally rotated to apply magenta color ink to the printing paper 2.
When a magenta printing is performed by heat-transferring to the printing sheet, then the printing sheet 2 is reversely fed and the ink film 6 is conveyed to print cyan in the same manner as described above, a color image is printed on the printing sheet 2. is there.

[Problems to be Solved by the Invention] By the way, in the conventional thermal transfer type color printer,
When the thermal head 10 thermally transfers the ink of the ink film 6 onto the printing paper 2, the ink film 6 is thermally contracted by the heat of the thermal head 10, so that wrinkles occur. For this reason, there is a portion in which the ink film 6 is folded and brought into close contact with the printing paper 2. When the thermal transfer is performed in such a state, the ink is difficult to be transferred in the folded portion of the ink film 6, so that the transferred image may have uneven color or may not be transferred, so that a desired image cannot be obtained. There was an inconvenience. In color printing in which a plurality of colors are superposed and transferred, this remarkably appears as color unevenness in the image, which deteriorates the image quality.

The present invention has been made in view of the above circumstances, and an object thereof is to prevent generation of wrinkles due to thermal contraction of an ink film, and therefore, uneven density, uneven color or transfer to a transferred image. It is an object of the present invention to provide a thermal transfer printer capable of reliably printing desired characters and colors with good image quality by eliminating unprinted portions.

[Means to be Solved by the Invention] In order to achieve the above object, the present invention provides an ink film supply roll for supplying an ink film, a take-up roll for winding an ink film, a platen roller for conveying printing paper, and this platen. The thermal head is provided so that it can be pressed into contact with and separated from the roller, the printing paper is wrapped around the outer peripheral surface of the platen roller, and the thermal head is attached to the platen roller while the ink film is wrapped around the outer side of the printing paper. In a thermal transfer printer that prints by thermally transferring the ink of the ink film to the printing paper by the heat of the thermal head while pressing, a tension applying means for applying a tension to the ink film between the ink film supply roll and the thermal head only when the thermal head is pressed. Is provided.

[Operation] According to the present invention, since the ink film is printed while being pulled, it is possible to prevent the ink film from being thermally shrunk by the heat of the thermal head, and thus to prevent wrinkles from occurring. Therefore, the transferred image has no density unevenness, color unevenness, or a non-transferred portion.

Further, since the ink film is conveyed by the platen roller during printing, the take-up roll only needs to wind up the ink film fed from the platen roller, so tension is applied to the ink film between the ink film supply roll and the thermal head. However, the extra torque is not applied to the winding roll motor.

On the other hand, when printing is not performed, no tension is applied to the ink film, so that a conventional capacity motor is sufficient and a large torque motor is not required.

[Embodiment] An embodiment in which the present invention is applied to a thermal transfer color printer will be described below with reference to FIGS. 1 and 2.

The same components as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 2, 11 and 12 are holding shafts for holding the ink film supply roll 7. These supply shafts 11, 1
Reference numeral 2 is rotatably attached to the printer body 1 so that the axes thereof coincide with each other. A holding member 1 for holding the ink film supply roll 7 is provided at opposite shaft ends of the holding shafts 11 and 12.
3 and 14 are attached respectively. The ink film supply roll 7 is attached between the holding members 13 and 14, and is held by the biasing force of the coil spring 15, so that the holding shafts 11 and 12 and the ink film supply roll 7 rotate integrally.

A friction clutch 16 is attached to the other shaft end of the holding shaft 11. The friction clutch 16 is configured as follows. That is, the friction plate 19 is attached to the clutch shaft 18 fixed to the holding shaft 11 by the set screw 17. The friction plate 19 forms the holding shaft 11 in a vertical cross-sectional shape “D” shape, and at the same time, the clutch shaft 1
The hole shape of 8 is also formed in a “D” shape and fitted therein, so that it can slide on the clutch shaft 18 in the axial direction and rotates together with the clutch shaft 18. A friction member 20, a friction plate 21, and a friction member 22 are loosely fitted on the clutch shaft 18 between the friction plate 19 and the friction plate 18a formed on the clutch shaft 18 in a brim shape. Saw-toothed teeth 21a, 21a ... Are formed on the outer periphery of the friction plate 21. The friction plate portion 18a, the friction member 20, the friction plate 21, the friction member 22, and the friction plate 19 are pressed against each other by a coil spring 24 interposed between the friction plate 19 and the adjustment nut 23. The adjusting nut 23 is screw-fitted to the clutch shaft 18 and can adjust the biasing force of the coil spring 24.

In FIG. 1, reference numeral 25 denotes a lever rotatably attached to a fulcrum 26 attached to the printer body 1.
An engaging projection 25a is formed on the top end of the lever 25, and the engaging projection 25a is formed on the tooth 21 of the friction plate 21.
It is adapted to engage with the recess between a, 21a .... The lever 25 is connected to a rod 28 by a connecting pin 27 provided between the engaging protrusion 25a and the fulcrum 26, and the rod 28 is connected to an actuator 29 that moves the rod 28 in the direction of arrow Y4 in the drawing. They are connected by a pin 30. The actuator 29 is connected to a control device (not shown) and is activated only when the thermal head 10 is pressed against the platen roller 5. When the actuator 29 is actuated, the lever 25 rotates about the fulcrum 26 as a fulcrum in the direction of the arrow Y5 in the figure, and the locking projection 25a is engaged with one of the recesses between the teeth 25a of the friction plate 21. The lever 25 is connected to the coil spring 32 by a locking pin 31 provided below the fulcrum 26, and the coil spring 32 is fixed to the printer body 1. When the operation of the actuator 29 is stopped, the coil spring 32
Thus, the lever 25 is rotated in the direction opposite to the arrow Y5 in the drawing and separated from the friction plate 21.

In the thermal transfer type color printer having the above configuration, when the thermal head 10 is pressed against the platen roller 5 for printing, one of the recesses between the teeth 21a of the friction plate 21 is engaged with the protrusion of the lever 25. Since 25a is engaged, the ink film supply roll 7 is braked by the frictional force between the friction plate 21 and the friction members 20 and 22, and tension is applied to the ink film 6 between the thermal head 10 and the ink film supply roll 7. . As a result, it is possible to prevent the ink film 6 from being thermally shrunk by the heat of the thermal head 10, and it is possible to prevent the generation of wrinkles. Therefore, the transferred image does not have density unevenness, color unevenness, or a non-transferred portion, and desired characters and colors with good image quality can be reliably printed.

Further, during printing, since the ink film 6 is conveyed by the platen roller 5 together with the printing paper 2, the take-up roll 9 may take up the ink film 6 sent from the platen roller 5, so that the ink film supply roll 7 and thermal Even if tension is applied to the ink film 6 between the heads 10, the motor of the take-up roll 9 does not receive an excessive amount of torque. On the other hand, when printing is not performed, the lever 25 is separated from the friction plate 21 and the ink film supply roll 7 is not braked, so that no tension is applied to the ink film 6, so that a conventional motor having a large capacity and a large torque can be used. do not need. Therefore, there is an advantage that a high-quality image can be obtained without increasing the size of the motor that drives the winding roll 9.

[Effects of the Invention] As described above, in the present invention, since the tension applying means for applying tension to the ink film between the ink film supply roll and the thermal head is provided only when the thermal head is pressed, the ink film is pulled. Since printing is performed while being heated, it is possible to prevent the ink film from shrinking due to the heat of the thermal head.
Therefore, it is possible to prevent wrinkles from occurring.
Therefore, the transferred image does not have density unevenness, color unevenness, or a non-transferred portion, and it is possible to reliably print desired characters and colors with high image quality.

Furthermore, since the ink film is conveyed by the platen roller during printing, the take-up roller only has to take up the ink film sent from the platen roller, so tension is applied to the ink film between the ink film supply roll and the thermal head. However, the extra torque is not applied to the winding roll motor. On the other hand, when printing is not performed, no tension is applied to the ink film, so that a conventional capacity motor is sufficient and a large torque motor is not required. Therefore, there is an advantage that a high quality image can be obtained without increasing the size of the motor that drives the winding roll.

[Brief description of drawings]

1 and 2 are views showing an embodiment of the present invention. FIG. 1 is a schematic side view showing the structure of a printer mechanism section, and FIG. 2 is a sectional view of an ink film supply roll section. FIGS. 3 to 5 are views showing a conventional thermal transfer type color printer. FIG. 3 is a schematic side view showing the configuration of a printer mechanism section, and FIG. 4 is a view showing a printing paper and a sprocket pin of a platen roller. FIG. 5 is a plan view showing an engaged state, and FIG. 5 is a plan configuration diagram of the ink film. 2 ... Printing paper, 5 ... Platen roller, 6 ... Ink film, 7 ... Ink film supply roll, 9 ... Winding roll, 10 ... Thermal head, 11 ... Holding shaft, 16 ... Friction clutch, 21 ...... Friction plate, 21a ...
… Tooth, 25 …… Lever, 25a …… Engaging protrusion, 29 ……
Actuator.

Claims (2)

[Claims] 1. An ink film supply roll for supplying an ink film, a take-up roll for winding up the ink film, a platen roller for conveying printing paper, and a thermal head provided on the platen roller so as to be capable of pressure contact and separation. The printing paper is wrapped around the outer peripheral surface of the platen roller, and the ink film is further wrapped around the outer surface of the platen roller, while the thermal head is pressed against the platen roller while the thermal head heats the heat. In a thermal transfer printer that thermally transfers and prints the ink of the ink film onto the printing paper, a tension applying means for applying a tension to the ink film between the ink film supply roll and the thermal head is provided only when the thermal head is pressed. Characteristic thermal transfer printer. 2. The tension applying means applies a tension to the holding shaft of the ink film supply roll by attaching a friction clutch so that the frictional force of the friction clutch works only when the thermal head is pressed. The thermal transfer printer according to claim 1.