JPH0360678B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention applies voltage to a plurality of heat-generating resistive elements, and uses the heat generated by these elements to thermally transfer ink on a thermal transfer ink film to paper (thermal melting or thermal sublimation). The present invention relates to a thermal transfer ink film used in a printing device that forms arbitrary characters and figures on paper.

Conventional configuration and its problems Recently, high-definition CRT color displays have appeared in response to the increasing functionality of personal computers (word processing function, color graphic function, etc.), and color Demand for printing has increased. Under these circumstances, various types of color printers have been proposed, and will be explained below using a thermal transfer printer as an example.

FIG. 1 is a diagram showing the principle of thermal transfer, and FIG. 2 is a diagram showing the principle of subtractive color mixing. 1 is a thermal head having a plurality of heating resistive elements 1a; 2 is transfer paper (plain paper);
3 is a band-shaped ink film for thermal transfer; 3a is a film base material such as polyester;
A heat-melting ink, here magenta ink (hereinafter referred to as M), is applied on top. 4 is a platen that holds the transfer paper 2; In the figure, when a voltage is applied to the heating resistor element 1a of the thermal head 1, the heat generated by the heating resistor element 1a melts the band-shaped thermal transfer ink film 3 M, which is transferred to the transfer paper 2 and printed. will be carried out. In addition, the figure shows an example in which yellow ink (hereinafter referred to as Y) has been transferred in advance, and M is also transferred.
They are superimposed to form a red hue. By combining the three printing primary colors Y, M, and cyan ink (hereinafter referred to as C) as described above in accordance with the subtractive color mixing principle diagram shown in FIG. 2, color printing in seven colors can be realized. FIG. 3 and FIG. 4 are one embodiment thereof, and will be explained in detail. First, in FIG. 3, the band-shaped thermal transfer ink film 3 (hereinafter referred to as ink film) includes:
Y, M, and C are applied sequentially.
Detecting means 3b for each color, such as a bar code, is provided at the boundary of C. When the detection means 3b detects the color requested by the print data from the host computer, a voltage is applied to the heat generating resistor element 1a of the thermal head 1.
The thermal head 1 is scanned in the direction of the arrow α, melts the required ink, and transfers it to the transfer paper 2, thereby printing. The ink film 3 consumed at this time is wound up in the direction of the arrow γ. As described above, monochrome printing or multicolor printing is performed based on the print data, and when one line of printing is completed, the transfer paper 2 is moved in the direction of arrow β via the platen 4 and the paper feed mechanism (not shown). will be sent. Therefore, in the case of black printing, it is necessary to detect each of Y, M, and C, and to perform overlapping printing three times, so that the printing speed is reduced to 1/3 compared to the case of monochrome printing. Furthermore, depending on the order in which Y, M, and C are stacked, a difference occurs in the hue of black, resulting in poor black reproducibility.

Furthermore, since the images are overlapped three times, the scanning mechanism of the thermal head 1 in the α direction requires extremely high precision technology to avoid color shift. Also, Y of ink film 3,
It also has the disadvantage of consuming a large amount of M and C.

In order to eliminate the above drawback, as shown in Figure 4,
An ink film 3 has been proposed in which black ink (hereinafter referred to as B) is added next to Y, M, C, and B, and Y, M, C, and B are uniformly applied sequentially, but the black reproducibility and Although it is better than the case shown in Figure 3 in terms of printing speed reduction, when only black printing is performed,
This has the disadvantage that Y, M, and C are completely wasted.

Furthermore, since a four-color configuration of Y, M, C, and B is used for one line printing, the consumption of ink film increases compared to a three-color configuration of Y, M, and C.

Therefore, as is clear from the above explanation, in the conventional example, a large amount of ink film is consumed, which increases the printing cost, placing a large cost burden on the consumer, and also reduces the printing speed and reduces the thermal head scanning mechanism. This method has drawbacks such as requiring more precise technology than necessary. Furthermore, in the conventional example described above, the line sequential method using a strip-shaped ink film was explained.
In the case of the field sequential method using a sheet-like ink film as shown in FIG. 5, the consumption of ink film will further increase.

Purpose of the Invention The present invention eliminates the drawbacks of the conventional inkjet printer, has a simple configuration, significantly reduces ink film consumption, prevents a decrease in printing speed due to overprinting, and simplifies the thermal head scanning mechanism. The purpose of the present invention is to provide an ink film for thermal transfer that can be used for thermal transfer.

Structure of the Invention In order to achieve this object, the present invention provides a black ink layer that is formed on a base material and thermally melts or thermally sublimates when heated to a predetermined temperature or higher, and a black ink layer that is formed on a base material in different areas on the black ink layer. and a color ink layer of three primary colors that thermally melts or thermally sublimates at a temperature below the predetermined temperature.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 6 is a cross-sectional view of a main part showing an embodiment of the present invention, and in FIG. 6, a black thermofusible ink B is applied onto a film base material 3a of a strip-shaped ink film 3. A first layer 3d is formed.
Furthermore, on the first layer 3d, a heat-melting ink Y,
A second layer 3e is formed in which M and C are applied in a uniform manner, and the ink film 3 has a multilayer structure. 3b is a detection means for each color, Y, M, and C, which is constituted by a bar code or the like, and is
It is easily applied in the same manufacturing process as B in d. 4
1 is a platen, 2 is a transfer paper, and 1 is a thermal head having a plurality of heating resistive elements 1a. Here, the thermal melting temperature (=T ₁ ) of the first layer 3d is the same as that of the second layer 3e.
The ink has a thermal melting temperature (=T ₂ ) and physical properties of the ink that satisfy the relational expression T ₁ >T ₂ , that is, as shown in FIG. 7. In FIG. 7, the curved line indicates the first layer, and the curved line indicates the second layer. The above temperature characteristics can be mutually changed by changing the pigment of the ink and the components of the binder wax.

In this embodiment configured as described above, first, the second layer 3e of the ink film 3, for example, Y
By supplying thermal energy that thermally melts only Y by adjusting the applied pulse width, only Y is printed as shown in FIG. Furthermore, when it is desired to print black as shown in FIG. 9, it is preferable to supply thermal energy to the thermal head 1 to thermally melt the first layer 3d. That is, as is clear from the above embodiment, by controlling the thermal energy stepwise, it is possible to selectively print on the first layer 3d or the second layer 3e of the ink film 3, and the conventional example shown in FIG. For black printing, there is no need for overlapping at all, resulting in a decrease in printing speed, deterioration of black reproducibility, and ink film.
There is no consumption of Y, M, and C, and its practical effects are extremely large.

Furthermore, in FIG. 6, B was applied to the first layer 3d, but as shown in FIG. It is clear that printing in red, green, and blue can be easily performed using the subtractive color mixing principle diagram shown in FIG.

In the embodiments described above, color printing can be easily performed by using a multilayer ink film having a first layer and a second layer and controlling the thermal energy of the thermal head. Note that the materials for the first layer and the second layer may be those commonly used, and the melting or sublimation temperature can be arbitrarily set depending on the pigment to be mixed.

Effects of the Invention As is clear from the above explanation, according to the present invention, ink film consumption can be significantly reduced very easily, printing speed reduction due to overlapping printing can be prevented, and the thermal head scanning mechanism can be improved. It is possible to provide an ink film for a color printing device that can be simplified, and has great practical effects.

[Brief explanation of drawings]

Figure 1 is a diagram of the principle of thermal transfer, Figure 2 is a diagram of the principle of subtractive color mixing, Figures 3 and 4 are plan views of an embodiment of a conventional ink film, and Figure 5 is the main part of a conventional printing device. A perspective view, FIG. 6, FIG. 8, and FIG. 9 are sectional views of essential parts of an ink film for thermal transfer according to an embodiment of the present invention, FIG. 7 is a temperature characteristic diagram of the same embodiment, and FIG. 10 is a diagram of the present invention. FIG. 7 is a sectional view of a main part showing another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Thermal head, 1a... Heating resistance element, 2... Transfer paper, 3... Ink film for thermal transfer, 3a... Film base material, 3b... Detection means, 3d... First layer, 3e... ...Second layer, 4...Platen.

Claims (1)

[Scope of Claims] 1. A base material of an ink film; a black ink layer formed on the base material and thermally melted or thermally sublimated when heated above a predetermined temperature; and mutually different ink layers on the black ink layer. An ink film for thermal transfer, comprising: a color ink layer of three primary colors formed in a region and thermally melted or thermally sublimated when heated to a temperature equal to or lower than the predetermined temperature.