JPH01275163A - Sublimation type heat transferring method - Google Patents

Abstract

PURPOSE:To obtain an image of high quality by a high speed transferring by applying an impressed voltage corresponding to the number of applied pulses or the width of a pulse obtained to realize a predetermined transferring density and the gloss or more of a transferred surface to a thermal head. CONSTITUTION:Variable states of a dye density and a gloss corresponding to the number of applied pulses of a voltage of a color transfer unit 1 are obtained by experiments to obtain a density curve and a gloss curve. When a combination of an impressed voltage, the number of applied pulses or the width of the applied pulse to realize desired density and gloss from the curves is obtained and heat 4 is applied to dots of a thermal head to which a corresponding voltage is applied, dye is sublimated from a dye layer 3 to be flown, dyed on an acceptor 5 to form a transferred image. Thus, an image of the quality of desired density and gloss can be proved on the transferred surface, and a high speed transferring can be performed.

Description

[Detailed description of the invention] Limb Distortion Corporation The present invention relates to a sublimation type thermal transfer method.

In conventional sharp distortion thermal printers, ie, thermal transfer printers, a method using sublimable dyes has recently been developed in order to obtain high-quality color images, compared to a method using melt transfer type recording paper containing wax as a main component.

Thermal transfer color images produced by dye-sublimation thermal printers have the advantage of producing glossy, high-quality images similar to photographs, but it takes a long time to transfer the sublimation dye to sufficiently heat and sublimate it to achieve the desired transfer density. It takes time.

When a high voltage is applied to shorten the transfer time, in the sublimation type, the image loses its luster, and the ink sheet stretches and wrinkles occur, which adversely affects both the ink sheet and the quality of the image.

In the case of sublimation transfer, high image quality can be obtained by lowering the applied voltage and performing slow transfer, but there is a problem in that image quality deteriorates when attempting to increase the speed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a sublimation thermal transfer method that can achieve high image quality with high-speed transfer.

Structure In order to achieve the above object, the present invention finds a combination of applied voltage and number of applied pulses or pulse width that achieves a predetermined transfer density, and on the other hand, determines a combination of applied voltage and number of applied pulses or pulse width that achieves a predetermined transfer surface gloss level or higher. The method is characterized in that the number of pulses or the pulse width is determined, and at the determined number of applied pulses or the pulse width, an applied voltage corresponding to the number of applied pulses or the pulse width is applied to the thermal head.

The present invention will be described in detail.

The structure of the dye-sublimation thermal printer itself is well known, so a description thereof will be omitted.

In thermal transfer, it is required to obtain a transfer density as high as possible. The transfer density varies depending on the amount of energy applied to the thermal head, and the higher the energy, the higher the transfer density.

For example, a thermal head used for thermal transfer divides elements into even and odd numbers, and drives the even and odd elements with small pulse widths at different timings, as shown in FIG. There is a dd/even drive system, and the transfer energy for each dot is supplied by applying a given voltage for a given number of pulses. Note that the driving method is not limited to this example.

In color transfer, color transfer bodies such as cyan, yellow, and magenta are used by a thermal head.

For example, as shown in FIG. 2, a color transfer body 1 used for sublimation type thermal transfer has a transfer base 2 and a dye layer 3 formed on the transfer base 2, and heat 4 is applied to each dot by a thermal head. When applied, the dye sublimates and jumps out from the dye layer 3, and the sublimated dye stains the receptor 5 to form a transferred image.

In sublimation type thermal transfer, one dot has multi-gradation properties, and multi-gradation density can be obtained by applying energy to each dot.

The density of the transferred image changes due to the heat energy applied during thermal transfer, and at the same time, the glossiness of the transfer surface also changes during thermal transfer using a sublimation type color transfer material.

Experimentally determining the changes in density and glossiness with respect to the number of applied voltage pulses on the cyan color transfer material, the third
The results shown in the figure were obtained.

In the figure, the horizontal axis indicates the number of applied pulses, the left vertical axis indicates cyan density OD, and the right axis indicates glossiness %.

In FIG. 3, curve A is the concentration curve when the applied voltage is 18V, and curve B is the concentration curve when the applied voltage is 17V. -The force curve C is the glossiness curve when the applied voltage is 18V, and the curve is the glossiness curve when the applied voltage is 17V.From Figure 3, in the case of a cyan color transfer material, the maximum density is OD = Although an OD of about 2.2 can be obtained, in practice, an OD of about 1.8 is considered as a guideline for the maximum concentration based on working conditions. Therefore, in the following explanation, the maximum density of cyan is assumed to be 1.8.

In addition, odd/even depending on the pulse width as shown in Figure 1.
In driving experiments, when the maximum cyan density was 1.8,
The gloss shown in Table 1 was obtained, with the highest gloss being 62.5%.
of gloss is obtained, and as the applied voltage increases, the maximum gloss actually decreases.

Table 1 From Figure 3, the gloss increases as the density increases in the low density region, but the gloss decreases in the high density region from around 1.2, and if the applied voltage is low such as 17V compared to 18V, A high gloss of about 60% can be achieved up to a density of about 2.0, but when the applied voltage is 18■, a gloss of about 60% can only be achieved up to a density of about 1.4. The range of concentrations that can be obtained is reduced. However, in the case of 17V, the number of pulses, that is, the application time width must be increased in a high concentration region, which takes time.

The glossiness of the receiver, that is, the transfer paper, before transfer is about 43.5% in the case of a standard, so if you want to ensure that the glossiness after transfer by the color transfer material is at least as high as the glossiness of the receiver, As shown in FIG. 3, 17-2 requires 220 pulses to be applied, while 18V requires only about 150 pulses.

For this reason, it is convenient to set the applied voltage to about 18 V in order to obtain the desired gloss level with high-speed transfer.

Therefore, the iso-density curve for the cyan color transfer material was experimentally determined and was as shown in FIG. In FIG. 4, as an example, the relationship between the applied voltage and the number of pulses to obtain a density of 1.8 is shown by curve A, and the glossiness of the transfer surface at that time is shown by curve B.
is shown.

In the graph, the horizontal axis shows the number of pulses, the left vertical axis shows the voltage (■), and the right dark blue axis shows the gloss level %.

Both Figures 3 and 4 are shown for cyan only,
The maximum 4 degrees of cyan is 1.8. As for color transfer materials, the maximum density values for each color are slightly different from each other, but the trends of the isodensity curve and the glossiness curve are generally the same, so if only cyan is explained, the same applies to other colors as well. Therefore, no explanation is required. Although the density conditions and the like obtained for each color transfer material differ slightly depending on the type of receptor, that is, the transfer paper, and the type of ink sheet, that is, the transfer material, typical examples will be explained.

From FIG. 4, it can be seen that when the density is the same, the glossiness improves rapidly as the number of pulses increases. From this, it can be seen that for the same concentration, the higher the number of pulses, and therefore the lower the voltage, the better the glossiness. However, the larger the number of pulses, the slower the transfer speed.

Normally, the gloss of the receiver, that is, the transfer paper, is 4 before transfer.
It is about 3.5%. Naturally, there are variations depending on the paper quality, etc., and not all glossiness is this high, but a standard example is shown. If you try to guarantee a gloss level higher than that of this standard example on the transfer surface, it is clear from Figure 4 that the gloss level is at least 205 mm.
The pulse and voltage must be at a maximum of 18.5 V.

For colors other than cyan, when the applied voltage is 18.5 V and the number of applied pulses is 205, magenta is 0D = 1.45.
, yellow has OD = 0.6, black (3 colors stacked)
It was found that a maximum concentration of OD = ], 6 can be achieved.

The gloss level of 43.5% of the above-mentioned receptor was used as the dark value to indicate the presence or absence of gloss, but in order to obtain a photograph-like image quality,
The darkness value of the presence or absence of luster must be officially determined through a magic test. The number of pulses 205 mentioned above is actually slightly larger than 205 because γ correction (temperature correction), thermal control, and environmental temperature correction must be performed.

■ According to the present invention, when the transfer surface is glossy, the combination of the applied voltage and the number of applied pulses or the applied pulse width that achieves the desired 4 degrees, for example, the maximum density, for any color transfer material is determined, and the desired gloss is obtained. The number of applied pulses or the width of the applied pulses corresponding to the degree of It is possible to guarantee image quality in terms of density and gloss, and also enables high-speed transfer.

[Brief explanation of the drawing]

Figure 1 shows the odd /eν when applying to the thermal head.
2 is a schematic illustration of a sublimation type color transfer body, FIG. 3 is a density characteristic curve and a glossiness characteristic curve, and FIG. 4 is an isodensity curve and a glossiness curve. It is.

Claims (1)

[Claims] In a sublimation thermal transfer method using a sublimation ink sheet, the combination of applied voltage and number of applied pulses or pulse width that achieves a predetermined transfer density is determined, and on the other hand, the number of applied pulses that achieves a predetermined gloss level or higher on the transfer surface. Alternatively, a sublimation thermal transfer method is characterized in that a pulse width is determined, and an applied voltage corresponding to the number of applied pulses or pulse width is applied to a thermal head at the determined number of applied pulses or pulse width.