JPH0890805A - Thermal transfer printer - Google Patents

Abstract

PURPOSE: To provide a thermal transfer printer in which a mechanism is simplified to be reduced in size and which has excellent printing quality for a recording medium such as a cut sheet having a rough surface and further can obtain a color image of high quality with less color shifting without increasing a non- printing area in the case of a color recording, etc. CONSTITUTION: A record sheet 11 is sandwiched between a platen roller 1 and a pressure roller 2, and ink is melted to be adhered to the sheet 1 by generating heat from a heat generator 4 provided at a thermal head 3 while conveying the sheet 11. After the image of one screen is formed, the contact of the sheet 11 with an ink film 8 is maintained only for a predetermined time, and then the rollers 11 and 2 are reversely rotated, and the sheet 11 and the film 8 are peeled and transferred. In the case of color printing, etc., while the sheet 11 remains sandwiched between the rollers 1 and 2, it is repeated. Thus, the positional deviation can be reduced.

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 for transferring an image of a melt transfer type onto recording paper to form an image, and more particularly to a recording paper cut into a predetermined length as the recording paper. The present invention relates to a thermal transfer printer used.

[0002]

2. Description of the Related Art A thermal transfer printer heats and melts ink applied on an ink sheet by energization and heat generation of a heating element based on input data, and transfers it onto recording paper by pressure contact force of a thermal head to form an image. Is. Therefore, with respect to a recording medium having a rough surface such as plain paper, the ink is not completely transferred to the recording medium, and there is a problem that the image quality is deteriorated such as a decrease in density or an image loss. It was Further, there has been a problem that a good image quality cannot be obtained also on a recording medium such as an OHP sheet which cannot obtain an adhesive force due to the penetration of ink.

To address these problems, for example, Japanese Patent Publication No. 62-
As disclosed in Japanese Patent No. 21635, paying attention to the fact that the time from the recording to the peeling of the ink film from the recording medium affects the image density and the image quality, and the recording is performed at a position a predetermined distance forward from the printing unit. A technique has been developed in which a peeling portion for peeling off the medium and the ink film is provided, and further, a means for cooling the ink film is provided between the printing portion and the peeling portion. According to this technique, the recording medium and the ink film can be peeled off while the temperature of the ink is lowered, and the image quality can be improved to some extent.

6 and 7 are explanatory views of the configuration and operation of a conventional thermal transfer printer. In the figure, 1 is a platen roller, 2 is a pressure roller, 3 is a thermal head, 4
Is a heating element, 5 and 6 are guide rollers, 7 is an ink film roll, 8 is an ink film, 9 is a base material, 10 is an ink layer, 11 is recording paper, 12 is a lever, 13 is an elastic member,
Reference numeral 14 is an ink image.

In this conventional thermal transfer printer, a guide roller 5 for peeling is arranged at a position separated by a predetermined distance D from the printing portion where the platen roller 1 and the thermal head 3 are in contact with each other. As shown in FIG. 6, the recording paper 11 is nipped between the platen roller 1 and the pressure roller 2 and the platen roller 1 is rotationally driven to convey the recording paper 11 in the direction of the arrow. On the other hand, the ink film 8 is conveyed from the ink film roll 7 through the guide roller 6 to the recording section. In the printing section, the ink layer 10 applied on the ink sheet 9 is selectively melted by the heat generated by the heating element 4 and is transferred to the recording paper 11 to form an image. After the image is formed, the recording paper 11 and the ink sheet 9 are in close contact with each other, and the process proceeds by a predetermined distance D. In the meantime, the ink heated and melted by the heating element 4 is cooled and solidified again. Then, the guide roller 5 separates the recording paper 11 and the ink sheet 9. At this time, the ink melt-transferred onto the recording paper 11 forms an ink image 14 on the recording paper 11.
Remain in.

When a recording paper 11 cut into a predetermined length is used in such a printer, the trailing edge of the recording paper 11 is placed at the platen roller 1 before the entire surface of the recorded image is peeled off.
Since it is separated from the pressure contact portion of the pressure roller 2, a pair of rotationally driven capstan rollers 15 is disposed in front of the peeling portion. As shown in FIG. 7, the capstan roller 15 conveys the recording paper 11 after the front end of the recording paper 11 is nipped by the capstan roller 15 and until the entire recorded image is peeled off. Is configured.

However, in the above-described conventional recording apparatus, since the recording paper 11 is ejected by the capstan roller 15, the capstan roller 15 is indispensable and there is a problem that the number of parts is large. Further, the recording paper 11 is conveyed by the pushing force of the platen roller 1 and the pressure roller 2, and the capstan roller 15
When the sheet is pinched by the sheet, the recording position may be displaced due to the tension or the like, and the image quality may be deteriorated.

Further, when the above-mentioned conventional recording apparatus is applied to a color thermal transfer printer, the following problems may occur. That is, three color images are repeatedly printed,
In a color thermal transfer printer capable of obtaining a color image for one screen, when recording for one color is completed, it is necessary to convey the recording medium in the direction opposite to the printing direction and return the recording medium to the same recording start position. There is. In the above-mentioned conventional recording apparatus, since the recording medium conveying means changes from the platen roller 1 to the capstan roller 15 during printing, the recording medium is conveyed in a state in which it is always in contact with only one roller. Compared to the transport method, there is a problem in that the print start position is more likely to be displaced due to skew and the bending of the recording medium, and the print quality is degraded due to the displacement of the overlapping positions of the three colors.

In order to solve such a problem, in the structure of the conventional recording apparatus described above, the recording paper 11 may be always in contact with the platen roller 1, but after the recording of each color, only the peeling distance D is applied. Since the peeling is performed first, a non-printing area having a peeling distance D or more is required at the trailing end of the recording paper 11. Further, when the recording paper 11 is always in contact with the capstan roller 15, printing cannot be performed on a portion having a peeling distance D or more from the capstan roller 15 to the printing portion, and the recording paper 11 is peeled on the front end portion. A non-printing area of the distance D or more is required. Thus, in the conventional recording device,
If one roller is always in contact with one roller to maintain the print quality, there is a problem that the effective print area becomes very small.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and simplifies the mechanism portion to reduce the size thereof, and also has a rough surface cut into a predetermined length. It is possible to perform recording with good print quality even on a medium, and when performing overprinting such as color recording, it is possible to achieve high quality with little color misregistration without increasing the non-printing area. It is an object of the present invention to provide a thermal transfer printer capable of obtaining a color image.

[0011]

SUMMARY OF THE INVENTION The present invention is a thermal transfer printer for forming an image by transferring a melt transfer type ink onto a recording paper, and holding the recording paper between the platen roller and the platen roller. Pressure roller to
An ink film carrying the ink and a thermal head for transferring the ink carried on the ink film onto the recording paper are provided, and when the recording is performed, the recording paper and the ink film are peeled off after the recording. The recording paper and the ink film are conveyed in a direction opposite to that during recording by rotating the platen roller and the pressure roller in a direction opposite to that at the time of recording after a predetermined time has elapsed. The recording paper and the ink film are separated from the trailing edge of the recorded image.

Further, in the thermal transfer printer having such a structure, the recording paper and the ink film are reciprocated a plurality of times to record a plurality of colors.

[0013]

According to the present invention, after the image is printed on the recording medium, the contact state between the recording medium and the ink film is maintained for a predetermined time, and then the recording medium and the ink film are conveyed in the opposite direction to the printing, and the trailing edge of the image is conveyed. Then, the recording medium and the ink film are peeled off. This eliminates the need for a capstan roller and separates the recording medium from the ink film in a state where the ink is cooled without increasing the non-printing area even on a recording medium with a rough surface cut to a predetermined length. It is possible to carry out the above, the ink transfer property is high, and a good recorded image can be obtained. Further, since the recording medium is configured to be conveyed in both the forward and reverse directions by only one roller, the rotation amount of the roller and the conveyance amount of the recording medium correspond to each other, so that the deviation of the recording start position of each color is reduced. Even in the case of color recording, since the overlay accuracy of a plurality of colors is high, a good color recorded image can be obtained.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic diagram showing an embodiment of a thermal transfer printer of the present invention. Reference numerals in the figure are the same as those in FIGS. 6 and 7. In this embodiment, a thermal transfer printer for color recording is shown.

A pressure roller 2 is pressed against the platen roller 1 with a predetermined pressure. The recording paper 11 is sandwiched between the platen roller 1 and the pressure roller 2 and is driven to rotate in both forward and reverse directions by a driving unit (not shown), so that the recording paper 11 is conveyed in the printing direction and the returning direction. The thermal head 3 is formed with a plurality of heating elements 4 in rows that generate heat when energized. Also,
The thermal head 3 is attached to one end of the lever 12. At the time of printing, the thermal head 3 is pressed against the platen roller 1 by the elastic member 13 attached to the other end of the lever 12. The lever 12 is driven by a driving unit (not shown) during non-printing, and the thermal head 3 is separated from the platen roller 1.

The ink film 8 is wound around a pair of ink film rolls 7. The ink film 8 includes a base material 9 made of, for example, polyethylene terephthalate, and three colors, for example, yellow (Y), magenta (M), and cyan (C), or black (K), which are applied in a surface-sequential manner on the base material 9. It is composed of four color ink layers 10 added with. The guide rollers 5 and 6 are rotatably supported, and define the conveyance direction of the ink film 8.

2 to 5 are explanatory views of an example of the operation in one embodiment of the thermal transfer printer of the present invention. In the initial state, the thermal head 3 is the platen roller 1
Is kept in a state of being separated from. In this state, the recording paper 11 is conveyed to the vicinity of the platen roller 1 by the recording paper conveyance means (not shown). The conveyed recording paper 11 is nipped between the platen roller 1 and the pressure roller 2, and is conveyed to the recording start position by the frictional force of these two rollers. On the other hand, the ink film 8
Is conveyed to the print start position for the first color. Then, the thermal head 3 separated from the platen roller 1 is pressed against the platen roller 1 so as to sandwich the recording paper 11 and the ink film 8, and the recording is started in the state shown in FIG.

Recording is performed by the heating element 4 based on the image data.
Are selectively energized to generate heat, and the ink layer 10b of the heat generating portion is generated.
Becomes molten and platen roller 1 and thermal head 3
It is performed by adhering to the recording paper 11 by the pressure contact force of. In this state, the recording paper 11 and the ink film 8
Are conveyed in the direction of the arrow. At this time, the recording paper 11 and the ink film 8 are still in close contact with each other. In this way, the first color image is sequentially formed on the recording paper 11 by adhesion.

The image of the first color is formed until just before the trailing edge of the recording paper 11 separates from the contact portion between the platen roller 1 and the pressure roller 2. FIG. 3 shows the state when the image formation of the first color is completed. At this time, there is a non-printing area where printing cannot be performed at the trailing edge of the recording paper 11. This size is from the contact portion between the platen roller 1 and the pressure roller 2 to the contact portion between the platen roller 1 and the thermal head 3. Will be regulated by the distance. This distance is much shorter than the peeling distance D in the conventional recording apparatus, and the printable area can be widened.

As shown in FIG. 3, when an image for one screen of the first color is adhesively formed on the recording paper 11, as described above,
The conveyance of the recording paper 11 and the ink film 8 is stopped immediately before the trailing edge of the recording paper 11 separates from the contact portion between the platen roller 1 and the pressure roller 2. At this time, the guide roller 5 on the downstream side of the printing unit is configured to be located on the downstream side of the front end of the recording paper 11. Therefore, the recording paper 11 and the ink film 8 are maintained in close contact over the entire surface of the image. Ink recording paper 1
In order to perform a complete transfer to No. 1, it is necessary to separate the recording paper 11 and the ink film 8 in a state where the ink is completely cooled and does not cause cohesive failure. Therefore, after the printing of the final portion of the image, the conveyance of the recording paper 11 and the ink film 8 is stopped as described above, and they are kept in close contact with each other for a predetermined time to cool the heated and melted ink portion. .

After the temperature of the ink has dropped after a certain period of time, as shown in FIG. 4, the thermal head 3 is separated from the platen roller 1, and the platen roller 1 is driven in the opposite direction to that at the time of printing. The recording paper 11 is conveyed in the direction opposite to that at the time of printing as indicated by the arrow. At the same time, ink film 8
Is also conveyed in the direction of the arrow opposite to that at the time of printing, the recording paper 11 and the ink film 8 are separated from the trailing edge of the image in the printing section, and the ink image 14 is transferred onto the recording paper 11. Chart paper 1
1 is returned to the print start position or higher, and all ink images 14
When is transferred onto the recording paper 11, the conveyance in the direction opposite to that during printing is stopped. At this time, the recording paper 11 is still held between the platen roller 1 and the pressure roller 2.

For example, when the print dots at the time of recording are in the shape of a triangle with rounded corners which is swollen backward due to the effect of heat storage,
By peeling from the rear end of the recording paper 11 as described above, it is possible to peel from the rear end of a print dot having a large adhesive force with the recording paper 11, and it is possible to improve the transfer efficiency. I also have.

When the peeling of the recording paper 11 and the ink film 8 is completed, the platen roller 1 is driven again in the printing direction to convey the recording paper 11 in the direction of the arrow, as shown in FIG.
Set it at the print start position. At the same time, the ink film 8 is conveyed in the direction of the arrow and set at the print start position for the second color. With the above process, the recording operation for one screen of the first color is completed. In the same manner, recording of the second and subsequent colors is performed, and ink images of respective colors are overwritten to form a color image for one screen.

The recording paper 11 on which recording of a plurality of colors has been completed is rotated by rotating the platen roller 1 in the opposite direction to that at the time of printing, and when peeling and transferring the last color, the conveyance path of the recording paper 11 (not shown) is switched and returned. The sheet may be discharged or conveyed to the sheet discharge roller.

As described above, according to the present invention, only the platen roller 1 is driven to perform both the feeding and feeding of the recording paper 11 during printing and the returning and feeding of the recording paper 11 during non-printing. As a result, it is possible to prevent the deviation of the print start position for the second and subsequent colors and obtain a high quality print image. Further, since the peeling transfer is performed after cooling for a predetermined time after the melt-adhesion of each color, a good image can be obtained even when printing is performed on a rough cut paper or the like. Further, the capstan roller, which is indispensable in the conventional recording apparatus, is unnecessary, and the apparatus can be downsized and the cost can be reduced.

The present invention is not limited to the above-described embodiment, but can be applied to, for example, a monochrome thermal transfer printer, a sublimation printer, or the like. It is also possible to use an OHP film as the recording medium.

[0027]

As is clear from the above description, the thermal transfer printer of the present invention does not peel off the recording paper and the ink film during printing, maintains them in close contact for a predetermined time, and cools the melted ink portion sufficiently. After that, the recording paper is conveyed in the reverse direction, and the recording paper and the ink film are separated from the trailing edge of the image. This improves the transferability of ink to recording paper,
An excellent recorded image can be obtained, and it is not necessary to enlarge the non-printing area even when a cut sheet is used.
Further, since the platen roller, which is always in contact with the recording paper, carries the paper in both the forward and reverse directions, the deviation of the print start position for each time can be reduced when performing multiple times of overprinting such as color printing. The effect is that an image with no color shift can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a thermal transfer printer of the present invention.

FIG. 2 is an explanatory diagram showing a state at the start of printing of the first color in an example of the operation in one embodiment of the thermal transfer printer of the present invention.

FIG. 3 is an explanatory diagram showing a state at the end of fusion bonding of the first color in an example of the operation in one embodiment of the thermal transfer printer of the present invention.

FIG. 4 is an explanatory diagram showing a state at the time of peeling transfer by returning conveyance in an example of the operation in one embodiment of the thermal transfer printer of the present invention.

FIG. 5 is an explanatory diagram showing a state at the time of starting printing of the second color in an example of the operation in one embodiment of the thermal transfer printer of the present invention.

FIG. 6 is a configuration diagram of a conventional thermal transfer printer.

FIG. 7 is an explanatory diagram showing a state at the end of printing in the conventional thermal transfer printer.

[Explanation of symbols]

1 ... Platen roller, 2 ... Pressure roller, 3 ... Thermal head, 4 ... Heating element, 5, 6 ... Guide roller,
7 ... Ink film roll, 8 ... Ink film, 9 ...
Substrate, 10 ... Ink layer, 11 ... Recording paper, 12 ... Lever,
13 ... Elastic member, 14 ... Ink image.

Claims (2)

[Claims] 1. In a thermal transfer printer for forming an image by transferring a melt transfer type ink onto a recording sheet, a platen roller, a pressure roller for sandwiching the recording sheet between the platen roller, and the ink. An ink film to be carried, and a thermal head for transferring the ink carried on the ink film onto the recording paper,
During recording, after recording, the recording paper and the ink film are conveyed in a state in which they are not separated from each other, and after a lapse of a predetermined time, the platen roller and the pressure roller are rotated in the opposite direction to the recording. A thermal transfer printer, wherein the recording paper and the ink film are conveyed in a direction opposite to that at the time of recording by peeling the recording paper, and the recording paper and the ink film are separated from the trailing end of the recorded image. 2. The thermal transfer printer according to claim 1, wherein the recording paper and the ink film are reciprocated a plurality of times to record a plurality of colors.