JPH08258305A - Thermal transfer printer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a thermal transfer printer that does not cause wrinkles on the ink ribbon, enables high-quality high-speed printing without printing spots, and has high color reproducibility during color printing. The ink is transferred by a thermal head 2 having a width narrower than that of the ink ribbon for heating a required portion in the width direction of the ink ribbon 5 coated with the ink to transfer the ink to the printing paper 11. Immediately after ink ribbon 5
The heater 17 having a width wider than that of the ink ribbon 5 reheats the ink ribbon 5 to make the temperature of the ink ribbon 5 uniform in the width direction, so that the stretching of the ink ribbon 5 is made uniform with respect to each part in the width direction. The generation of wrinkles on the ink ribbon 5 is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal transfer printer capable of high speed and high quality printing.

[0002]

2. Description of the Related Art Thermal transfer printers perform printing by heating a predetermined portion of an ink ribbon coated with molten ink or sublimation ink with a print head and thermally transferring the ink onto a printing paper. More specifically, the ink is applied to one surface of the thin film-shaped ink ribbon, and the ink surface of the ink ribbon and the printing paper are brought into pressure contact with each other. Then, the ink is transferred to the printing paper by heating a predetermined portion of the surface of the ink ribbon on which the ink is not applied by the print head.

FIG. 10 is a side sectional view showing an example of a schematic structure of a conventional thermal transfer printer. In FIG. 10, the ink ribbon 5 is supplied from the supply roller 6, passes between the platen roller 8 and the thermal head 2, and is wound up by the winding roller 7. In this figure, the lower surface of the ink ribbon 5 is the ink surface 5a. On the other hand, the sheet 11 is nipped by the pinch roller 10 and the platen roller 8 and between the pinch roller 9 and the platen roller 8 and conveyed in the direction of arrow A.

The thermal head 2 is formed as a part of the thermal head assembly 1, and the thermal head assembly 1 is also integrally formed with a peeling plate 3 and a heat sink 4. When transferring the ink applied to the ink ribbon 5 to the paper 11, the ink ribbon 5
And the paper 11 are fused by the ink, but the peeling plate 3
Are attached to separate them. The heat sink 4 is attached to appropriately dissipate the heat of the thermal head 2.

FIG. 11 shows the ink ribbon 5 and the thermal head assembly 1 from the ink surface 5a side in FIG.
It is the figure (bottom view) which looked at. In the figure, reference numeral 13 denotes a heating element attached to the thermal head 2, and a plurality of minute heating elements are arranged in the width direction of the ink ribbon 5. The total length of the heating element 13 is shorter than the total width of the ink ribbon 5.

FIG. 12 is a sectional view showing an example of the structure of the ink ribbon 5. Ink ribbon 5 as shown in this figure
Is composed of three layers, an ink layer 15, a base layer 14, and a coating layer 16. The mechanical strength of the ink ribbon 5 is generally determined by the material of the base layer 14. For the base layer 14, PET (polyethylene terephthalate), condenser paper, aramid paper, or the like has been put into practical use, but generally, a PET film is often used because of its low cost and high performance.

[0007]

The heat generation temperature of the above-mentioned heating element 13 reaches 300 to 600 ° C. It is also considered that the temperature of the base layer 14 locally rises to near 200 ° C. FIG. 13 is a diagram showing actually measured values of thermal deformation characteristics of the base layer 14 using a PET film. Here, the upper end of the ink ribbon 5 having a width of 50 mm and a length of 220 mm is fixed to the upper part of the constant temperature layer, a weight of 0.5 kg is hung at the lower end thereof, and the elongation rate with respect to the elapse of time when the temperature of the base layer 14 is constant The change was measured. As can be seen from FIG. 13, the PET film base layer 14 loses its mechanical strength at a temperature of 190 ° C. or higher.

When the ink applied to the ink surface 5a of the ink ribbon 5 is transferred to the paper 11 (during printing), both are sandwiched between the thermal head assembly 1 and the platen roller 8 and applied with a predetermined pressure. Press. At the same time, the paper 11 is conveyed by the pinch roller 9 and the platen roller 8 while heating a required portion of the thermal head 2 by the heating element 13, and the ink ribbon 5 is wound by the winding roller 7. In this case, as shown in FIG. 14, the area of the ink ribbon 5 heated by the heating element 13 is defined as the area 5.
The area other than h is called area 5c.

As described above, since the ink ribbon 5 is wound around the winding roller 7 during printing, tension is applied in this direction. Therefore, as can be seen from FIG. 13, the portion of the ink ribbon 5 which is heated by the heating element 13 is stretched.
FIG. 15 is a diagram showing an example of the stretched state of the ink ribbon 5 during printing, and the length of the arrow in this figure represents the stretched amount (deformation amount). Ink ribbon 5
Is stretched only in the region 5h, and the amount of deformation is different depending on each portion in the width direction. Due to this difference in the amount of deformation, wrinkles occur in each part of the ink ribbon 5 during printing. In Figure 16,
An example of the ink ribbon 5 in which wrinkles 5w are generated is shown.

In the ink ribbon 5, the portion where the wrinkle 5w is generated as described above has a reduced adhesiveness with the paper 11,
For this reason, the transferability of the ink is lowered, and there is a problem in that printing unevenness occurs. Further, although the single-color thermal transfer printer has been described above, in the color thermal transfer printer, as shown in FIGS. 17 (a) and 17 (b), the ink ribbon 5 is set to Y at a constant length L matched to the paper 11. Ink of (yellow), M (magenta), C (cyan) or Y, M, C, K (pure black) is applied. Then, while the ink ribbon 5 is being wound by the take-up roller 7 in FIG. 1, the paper 11 is reciprocated in the arrow A and B directions, and the respective colors are overlapped and printed. At this time, the ink ribbon 5
Wrinkles 5 at different positions depending on each color of Y, M, C, (K)
w is generated. Therefore, there arises a problem that color spots are generated or the color reproducibility is remarkably reduced.

Further, in the ink ribbon 5, the base layer 14 is more suitable for full surface printing than local printing and for high speed printing than low speed printing.
The temperature rises, and the wrinkles 5w are significantly generated. As a result, the image quality is significantly impaired, leaving a problem in practical use. The present invention has been made under such a background, and wrinkles do not occur on the ink ribbon, which enables high-quality high-speed printing without printing spots, and color reproducibility in color printing. It is intended to provide a high thermal transfer printer.

[0012]

In order to solve the above-mentioned problems, in the invention described in claim 1, the ink ribbon to which the ink is applied and the required portion in the width direction of the ink ribbon are heated. And a reheating means for reheating the ink ribbon immediately after the transfer of the ink by the thermal head, the width of the thermal head being the width of the ink ribbon. The width of the reheating means is wider than the width of the ink ribbon.

Further, in the invention according to claim 2,
The thermal transfer printer according to claim 1, wherein the thermal head comprises a heating element group, and the width of the reheating means is at least wider than the heating element group, and preferably wider than the ink ribbon width. And

Further, in the invention according to claim 3,
In the thermal transfer printer according to any one of claims 1 and 2, the reheating means has a heating element over the entire width direction thereof.

Further, in the invention described in claim 4,
In the thermal transfer printer according to claim 1 or 2, the reheating means has small heating elements at positions corresponding to both sides of the ink ribbon.

Further, in the invention according to claim 5,
3. The thermal transfer printer according to claim 1, wherein the reheating means has a plurality of minute heating elements over the entire widthwise direction thereof, and the minute heating elements form a staggered arrangement. It is characterized by

Further, in the invention according to claim 6,
The thermal transfer printer according to any one of claims 1 to 5, further comprising a transfer means and a platen roller which are in pressure contact with each other and hold the ink ribbon and the printing paper.
The transfer means has a first contact with the platen roller.
And a second pressure contact surface, the thermal head is attached to the first pressure contact surface, and the reheating means is attached to the second pressure contact surface.

Further, in the invention according to claim 7,
The thermal transfer printer according to any one of claims 1 to 5, wherein a winding unit that winds the ink ribbon, and a guide roller that changes a conveyance direction of the ink ribbon between the thermal head and the winding unit. And
The reheating means is formed in the guide roller.

According to the invention described in claim 8,
An ink ribbon coated with ink and heating means for heating the ink ribbon are provided, and the heating means prints the ink on a portion corresponding to the inside of the width of the ink ribbon in the width direction. A portion having a plurality of minute heating elements to be transferred to a sheet and not having the minute heating elements,
Each has a sub-heating element that heats to a temperature at which the ink is not transferred to the printing paper, and the minute heating element and the sub-heating element are formed in a line on the surface of the heating unit.

[0020]

According to the first aspect of the invention, a thermal head having a width narrower than that of the ink ribbon is used to transfer a desired portion of the ink ribbon coated with the ink in the width direction by heating the ink. The reheating means having a wider width than the ink ribbon reheats the ink ribbon immediately after the transfer of the ink, so that the temperature in the width direction of the ink ribbon is made uniform. According to the second aspect of the present invention, the ink ribbon immediately after the transfer of the ink is reheated at least wider than the width of the heating element group forming the thermal head, and preferably wider than the width of the ink ribbon. Means reheat. According to the third aspect of the invention, the heating element provided over the entire width of the reheating means in the width direction makes the temperature of the ink ribbon in the width direction uniform. According to the fourth aspect of the invention, in the reheating means, the small heating elements provided at the positions corresponding to both sides of the ink ribbon make the temperature of the ink ribbon uniform in the width direction. Also,
According to the fifth aspect of the present invention, the plurality of minute heating elements provided in a zigzag arrangement over the entire widthwise direction of the reheating means makes the temperature in the widthwise direction of the ink ribbon uniform. Further, according to the invention described in claim 6, it is attached to the second pressure contact surface of the transfer means having the first and second pressure contact surfaces for sandwiching the ink ribbon and the printing paper between the platen roller. The reheating means uniformizes the temperature of the ink ribbon in the width direction. Further, according to the invention described in claim 7, the reheating means formed in the guide roller for changing the carrying direction of the ink ribbon between the thermal head and the winding means controls the temperature in the width direction of the ink ribbon. Make it uniform. Also,
According to the invention described in claim 8, a plurality of minute heating elements for transferring the ink to the printing paper are provided in the area corresponding to the inner side of the width of the ink ribbon, and the ink is printed in the areas not having the minute heating elements. The sub-heating element that heats to a temperature that is not transferred to
The heating means formed in a line on the surface makes the temperature of the ink ribbon in the width direction uniform.

[0021]

EXAMPLES Examples of the present invention will be described below. In the following embodiment, an example applied to a single color thermal transfer printer will be described. A. First Embodiment FIG. 1 is a configuration diagram showing a schematic configuration of a first embodiment of the present invention. The thermal head assembly 1 is composed of a heat sink 4 located above it, a thermal head 2 attached to the lower surface of the heat sink 4, and a peeling plate 3 attached to the right side of the heat sink 4. In the thermal head assembly 1, the lower surface of the thermal head 2 is pressed against the platen roller 8.

On the left side of the thermal head assembly 1,
A supply roller 6 parallel to the platen roller 8 is provided,
The ink ribbon 5 is wound around the supply roller 6.
A take-up roller 7 parallel to the platen roller 8 is provided on the right side of the thermal head assembly 1, and the ink ribbon 5 is taken up by the take-up roller 7.

On the left and right sides of the platen roller 8,
A pinch roller 10 and a pinch roller 9 which are parallel to the platen roller 8 are provided, and are pressed against the platen roller 8. The sheet 11 is nipped and conveyed between the pinch roller 10 and the platen roller 8 and between the pinch roller 9 and the platen roller 8. Peeling plate 3
A heater 17 is attached to the lower end of the. Figure 2
FIG. 2 is a view (bottom view) of the ink ribbon 5 and the thermal head assembly 1 seen from the ink surface 5a side in FIG.

3 (a) and 3 (b) are views showing a schematic structure of the heater 17 in the embodiment, which are a bottom view and a side view, respectively. As shown in FIG.
A groove 17a having a semicircular cross section is formed at the tip of 7 and a heating element 19 such as a nichrome wire is attached to the groove 17a with an insulating layer 18 made of fluororesin or the like sandwiched therebetween. There is. The width of the heater 17 is the width of the ink ribbon 5
Is wider than the width W of the ink ribbon 5, and the entire area of the base layer 14 (see FIG. 12) is heated from the coating layer 16 side of the ink ribbon 5 to make the amount of stretching in each portion of the ink ribbon 5 in the width direction uniform. Suppresses the generation of wrinkles.

B. Second Embodiment FIGS. 4A and 4B are views showing a schematic configuration of a heater 27 in a second embodiment of the present invention, which are a bottom view and a side view, respectively. The heater 27 has recesses 27a, 27a having a semicircular cross section formed in the vicinity of the left and right ends of the lower surface of the heater 27.
Short heating elements 29, 29 are attached with 28 in between. Here, the mounting position of the heating elements 29, 29 (the concave portion 2
The positions 7a and 27a) coincide with the passage positions of the regions 5c and 5c (see FIGS. 14 and 15) located on both sides of the ink ribbon 5.

That is, according to this embodiment, the areas 5c and 5c of the ink ribbon which are not heated by the thermal head 2 at the time of printing are heated by the heating elements 29 and 29,
This eliminates the temperature unevenness in the width direction of the ink ribbon 5,
The wrinkles of the ink ribbon 5 are prevented from occurring.

The second embodiment may have the following configuration. FIG. 5A is a side sectional view showing a detailed configuration example of the peeling plate 40 integrally formed with the heater. Further, FIG. 5B is a view (front sectional view) taken along the line A in FIG. 5A. In the peeling plate 40, one end (lower end in FIG. 5) 40a of an aluminum plate is curved, and a polyimide resin layer 41 is formed on the surface of this curved surface. An alumina layer 42 having a thickness of about 2 μm is formed on the polyimide resin layer 41.
Is formed by vapor deposition, and a heater 43 made of a TaSiO ₂ resistance film is formed thereon. An electrode 44 is formed on each of the heaters 43 by aluminum vapor deposition, and leads 45 are formed.
Is formed on the electrode 44 by vapor deposition of TiW and Ni.
Further, a protective layer 46 made of SiO ₂ is covered from above.

C. Third Embodiment FIGS. 6A and 6B are diagrams showing a schematic configuration of a heater 37 in a third embodiment of the present invention, which are a bottom view and a side view, respectively. As shown in FIG.
A concave groove 37a having a semicircular cross section is formed at the tip of 7. Short heating elements 39-1, 39-2, ... Are sandwiched in the groove 37a with an insulating layer 38 made of fluororesin or the like interposed therebetween.
・ 39-n are arranged in two rows in a staggered arrangement at regular intervals. And these heating elements 39-1, 39-2 ... 39
-n can independently control heat generation.

This makes it possible to selectively heat the regions 5c and 5c located on both sides of the ink ribbon 5. At the same time, in the case of partial printing, it is possible to selectively heat even the portion inside the printed area 5h (see FIGS. 14 and 15) that is not printed.

D. Fourth Embodiment FIG. 7A is a diagram (bottom view) of the configuration of a thermal head 2a according to a fourth embodiment of the present invention as seen from the ink surface 5a side of the ink ribbon 5. In this embodiment, the heating elements 20, 20 are attached integrally with the heating element 13 in the thermal head 2a. A detailed bottom view of the heating element 20 portion is shown in FIG. As shown in FIG. 7B, in the thermal head 2a, the common electrode 21 is formed on the alumina plate 23 which is an insulator (dielectric). A plurality of minute heating elements 13a, 13a ... And a heating element 20 are arranged in a line on the common electrode 21, and further individual electrodes 22, 22 ...
· Connected by.

In this embodiment, the minute heating elements 13a, 13a
are arranged so as to correspond to the area 5h of the ink ribbon 5, and the heating elements 20 and 20 are arranged in the area 5h.
It is arranged so as to correspond to part c. Heating element 20,
Heating power is supplied to 20 from an electric power supply circuit (not shown), and the thermal head 2a uses the minute heating elements 13a, 13a ...
・ The heat generation power is supplied to each independently. Therefore, if a driver circuit is added in the control unit and heating power is supplied from the added driver circuit to the heating elements 20, 20, a power control circuit for each can be configured in a one-chip integrated circuit or the like. it can. Therefore, the thermal transfer printer can be downsized.

In this embodiment, the heating element 20,
20 is attached to a portion where the ink ribbon 5 and the paper 11 are in contact with each other. Therefore, when the temperature of the heating elements 20, 20 rises and the ink layer 15 of the ink ribbon 5 reaches the melting temperature, unnecessary ink is transferred to the paper 11. Therefore, it is necessary to set the temperature of the heating elements 20, 20 lower than the melting temperature of the ink layer 15. On the other hand, the length l'of the heating elements 20 and 20 is set to the minute heating element 13a.
By making the length l longer than the length l, the calorific value per unit area is suppressed as compared with the minute heating element 13a.

E. Fifth Embodiment FIG. 8 is a side sectional view showing the structure of the fifth embodiment of the present invention. An alumina plate is often used for the thermal head, but in the thermal head assembly 1b of this embodiment, the bottom of the thermal head 2b is formed of a metal plate. Since the thermal head 2b is a metal plate as described above, it can be easily formed into a complicated shape. Therefore, as shown in FIG. 8, the thermal head 2b is formed so as to be in contact with the platen roller 8 at two or more points, and the heating element 13 is arranged at one contact portion and the heater is provided at the other contact portion. Place 25. The shape of the heater 25 may be any of the shapes of the first to third embodiments described above.

F. Sixth Embodiment FIG. 9 is a side sectional view showing the structure of the sixth embodiment of the present invention. In this embodiment, a heater is built in the center of the winding side ribbon guide 26. Therefore, the winding-side ribbon guide 26 heats the ink ribbon 5 to make the amount of stretching in each part in the width direction uniform and suppress the occurrence of wrinkles. In this embodiment, the conventional thermal head assembly 1 can be used as it is. For this reason, there is no need to change the design of the precisely configured thermal head, which is convenient. Here, an example in which the heater is built in the central portion of the winding side ribbon guide 26 has been described, but the heater may be built in the central portion of the supply side ribbon guide 27.

In the above embodiments, an example in which the present invention is applied to a single color thermal transfer printer is shown, but the present invention is also applicable to a color thermal transfer printer. In this case, it is possible to eliminate color spots and the like caused by wrinkles generated on the ink ribbon during printing. As an example of this embodiment, in the thermal transfer printer using the peeling plate 38 shown in FIGS. 5A and 5B, when the thermal head 2 is supplied with electric power of each energy density to perform full-scale printing, the following is performed. The results were obtained. In this way, by making the amount of stretching of the ink ribbon uniform by the heater, it becomes possible to eliminate the wrinkles that occur in the ink ribbon.

[0036]

As described above, according to the present invention, since the temperature in the width direction of the ink ribbon is made uniform, it is possible to suppress wrinkles that occur during printing and to prevent printing spots. The effect is that high-quality high-speed printing is possible, and a thermal transfer printer with high color reproducibility can be realized in color printing.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a configuration of a first embodiment of the present invention.

FIG. 2 is a bottom view showing the external configuration of the thermal head assembly 1 in FIG.

3A and 3B are a bottom view and a side view showing the configuration of the heater 17 according to the first embodiment of the present invention.

FIG. 4 is a bottom view and a side view of a heater 27 according to a second embodiment of the present invention.

FIG. 5 is an integrally formed peeling plate 4 according to the embodiment.
It is a front sectional view and a side sectional view showing the composition of 0.

FIG. 6 is a bottom view and a side view of a heater 37 according to a third embodiment of the present invention.

FIG. 7 is a bottom view of a thermal head 2a according to a fourth embodiment of the present invention.

FIG. 8 is a side sectional view showing the configuration of the fifth embodiment of the present invention.

FIG. 9 is a side sectional view showing the structure of the sixth embodiment of the present invention.

FIG. 10 is a side sectional view showing a configuration example of a conventional thermal transfer printer.

11 is a thermal head assembly 1 in FIG.
It is a bottom view which shows the structure of.

FIG. 12 is a side sectional view showing an example of the configuration of the ink ribbon 5.

FIG. 13 is a diagram showing thermal deformation characteristics of a base layer 14 using a PET film.

FIG. 14 is a diagram showing a region 5c and a region 5h in the ink ribbon 5.

FIG. 15 is a diagram showing an example of a stretched state of the ink ribbon 5 during printing.

FIG. 16 is a diagram showing an example of the ink ribbon 5 in which wrinkles 5w are generated.

FIG. 17 is a diagram showing a color arrangement of Y, M, C or Y, M, C, K in the ink ribbon 5.

[Explanation of symbols]

1, 1b Thermal head assembly 2, 2a, 2b Thermal head 3 Peeling plate 5 Ink ribbon 7 Winding roller 8 Platen roller 11 Paper 13, 19, 20, 29 Heating element 39-1, 39-2 ... 39-n Heating element 17, 25, 27, 37 Heater 26a Winding side ribbon guide 26b Supply side ribbon guide

Claims (8)

[Claims] 1. An ink ribbon coated with ink, a thermal head that heats a required portion in the width direction of the ink ribbon to transfer the ink to a printing sheet, and the thermal head transfers the ink. Reheating means for reheating the ink ribbon immediately after, the width of the thermal head is narrower than the width of the ink ribbon, and the width of the reheating means is wider than the width of the ink ribbon. Printer. 2. The thermal head comprises a heating element group, and the width of the reheating means is at least wider than the heating element group, and preferably wider than the ink ribbon. The thermal transfer printer described in. 3. The thermal transfer printer according to claim 1, wherein the reheating unit has a heating element over the entire area in the width direction. 4. The thermal transfer printer according to claim 1, wherein the reheating means has small heating elements at positions corresponding to both sides of the ink ribbon. 5. The reheating means has a plurality of minute heating elements over the entire area in the width direction thereof, and the minute heating elements form a staggered arrangement. The thermal transfer printer according to any one of 1. 6. A transfer means, which presses the ink ribbon and the printing paper together, and a platen roller, which are in pressure contact with each other, and wherein the transfer means are in contact with the platen roller. The said thermal head is attached to the said 1st press contact surface, and the said reheating means is attached to the said 2nd press contact surface, It has any one of Claim 1 thru | or 5 characterized by the above-mentioned. Thermal transfer printer. 7. A winding means for winding the ink ribbon, and a guide roller for changing the carrying direction of the ink ribbon between the thermal head and the winding means, wherein the reheating means comprises the guide. The thermal transfer printer according to any one of claims 1 to 5, wherein the thermal transfer printer is formed in a roller. 8. An ink ribbon coated with ink, and heating means for heating the ink ribbon, wherein the heating means is provided in a portion corresponding to an inner side of the width of the ink ribbon in the width direction thereof. A plurality of minute heating elements for transferring the ink to the printing paper, and a sub-heating element for heating the ink to a temperature at which the ink is not transferred to the printing sheet, respectively The thermal transfer printer is characterized in that the minute heating element and the sub heating element are formed in a line on the surface of the heating means.