JPS63118291A - Thermal transfer recording method - Google Patents

Abstract

PURPOSE:To achieve clear recording with high density under a wide range of environmental temperature conditions, by forcibly cooling an ink to a temperature not higher than a top peak value measured by a differential scanning calorimeter (DSC), preferably, not higher than the solidifying temperature of the ink. CONSTITUTION:A printer of a portable word processor comprising a thermal head 5' so reconstructed as to achieve cooling by circulating a cooling medium in the interior of the head immediately after the application of a voltage is used. By using a thermal transfer ribbon employing an ink having a top peak temperature of, for example, 77 deg.C and a solidifying temperature of 75 deg.C, thermal transfer recording is performed at an environmental temperature of, for example, 45 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of Industry J 1-) The present invention is concerned with improving a thermal transfer recording method using a thermal head or the like.

(Prior art and problems to be solved by the invention) Thermal transfer, iL! The recording method has become widely used in recent years, including small word processors, because it allows the use of small and inexpensive recording devices, and its widespread use has been rapid.

However, thermal transfer recording methods have conventionally required high density (clear prints) only when used indoors such as offices where the environmental temperature is kept constant, but In the case of blinking, etc., it is not always possible to use only the ideal 10 temperature range, so conventional F
, 1% satisfactory recording with transfer recording method! There are now many cases where I am unable to do so.

The mechanism by which ink is transferred to the recording medium in this PJ transfer recording method using a thermal transfer ribbon is based on the output of the thermal head, the softening of the ink + i, t, the freezing point, and the melting temperature of the ink (G). The softening point is the temperature at which when solid ink is gradually heated, the ink begins to show adhesion (or adhesion) to the transfer target, and when heating continues, the ink turns into a gel (semi-molten). Although it becomes a state,
The temperature at which this state changes to a gel state is called the Q solidification point = solidification temperature, and the point at which it changes from a semi-molten state to an almost liquid state when heating is continued is the top beak (). There are three possibilities: m1 has an extremely small output from the thermal head, and an ink field F! of 1'λ degree, which is sufficient to soften the ink on the thermal transfer ribbon. ! If the output is to increase the capacity, the ink immediately after being applied is 4? By simply softening without melting, the surface of the ink develops tackiness, and the ink adheres to the object to be transferred with the adhesive force caused by this tackiness. At this time, if the temperature of the transferred object, which depends on the environmental temperature IQ, is sufficiently lower than the freezing point of the ink, l1l
The ink is then cooled and becomes almost completely solid.

In the second case, the output of the thermal head is normal,
If the output is enough to melt the ink,
Immediately after application, the ink on the thermal transfer ribbon is in a half-t8 molten state and has high adhesion and strong adhesion.
・The ink adheres to the object to be transferred due to the high tackiness and adhesive strength of the ink itself, and when the temperature of the object to be transferred at this time is sufficiently lower than the freezing point of the ink, the ink that adheres to the object to be transferred is immediately cooled down. It becomes almost completely solid state.

In the third case, the output of the thermal head is so large that the ink on the transfer ribbon is completely melted when it is applied.
, ylI4, the ink on the thermal transfer ribbon itself becomes completely molten and acts as an adhesive to adhere to the transfer target. At this time, if the temperature of the transfer object is sufficiently lower than the freezing point of the ink, the ink is immediately cooled and becomes almost completely solid.

In any of the above three cases, the environmental temperature is, for example, 30
If the temperature is below 11°C, it is sufficient for the ink to solidify.
degree, the ink quickly cools and completely solidifies,
If the ribbon and the transferred object are not peeled off, as shown in the figure, since the part 2 where the ink adheres to the transferred object 1 is firmly adhered, shear stress will be applied to the non-adhered part. As a result, the solid ink layer is destroyed and cut into non-adhesive portions 3.3', completing the transfer.

This is because the adhesive force at the interface between the transfer target and the ink and the cohesive force of the ink itself are greater than the adhesive force between the support of the thermal transfer ribbon and the ink, so the ink is not transferred to the transferred body. This is because that.

However, when performing thermal transfer recording in a place where the environmental temperature is 30°C or higher, for example, the temperature of the thermal transfer ribbon, platen, thermal head, transfer target, etc. must be 30°C or higher. , due to the relationship between the Q solid point and melting temperature of the ink used in conventional thermal transfer ribbons, when a normal energy is applied, the ink always melts with crystallinity lower than l-. It becomes a molten state. Also, since the temperature of the thermal transfer ribbon, platen, thermal head, transfer target, etc. is all above 30°C, the temperature of the ink does not drop instantly below the freezing point of the ink, unlike when it is below 30°C. ,
In this case, if we compare the adhesion force between the support of the thermal transfer ribbon and the ink, the adhesion force between the transferee and the ink, and the 491 force of the ink, we find that Any adhesive force at the ink interface will be greater than the cohesive force of the ink. Therefore, if the thermal transfer ribbon is peeled off from the object to be transferred in this state, a considerable amount of ink will remain on the support of the thermal transfer ribbon and will not be transferred to the object to be transferred. As a result, the quality of the transferred recording is not high enough for practical use in terms of both density and sharpness.

(Object of the Invention) The present invention provides a thermal transfer ribbon that is not affected by environmental temperature conditions, etc. It is an object of the present invention to provide a transfer recording method in which the density is reduced to 1 and clear recording is possible even in the case of high-temperature printing.

(Problem +: Lower stage and action to solve 1); In order to improve the density and sharpness of the transferred record in winter transfer recording, various methods and methods are used in P. The structure of the thermal transfer ribbon's 1 ink is made up of a number of continuous chambers, including the composition and formulation of the ink.
It is intended to be used indoors where the temperature is controlled to be below 0°C, and under a wide range of environmental temperature conditions such as the one provided by the present invention, especially in high temperature ranges. However, it is not possible to obtain high-density and clear records.

! The ink composition of the transfer ribbon is generally a mixture of heat-melting dye, dye 11 and/or pigment and binder, or 16 additives such as 1,1 surface/1r111 agent. Solid forms are often used. Even if this ink is solid at room temperature, it needs to be heated by the printer's heating means such as an electric current to melt it or soften it.
The molten or softened ink is transferred to a transfer target that is in close contact with the thermal transfer ribbon. , - the softening temperature of the ink is 35
℃ to 120℃, but in order to improve thermal response, we often use a material with a lower softening temperature.
In this case, the solidification temperature also tends to decrease. Therefore, 30
What if the record is 4 degrees in an environment below ℃? In the conventional method, the ink is sufficiently cooled below the solidification temperature and does not solidify, and the thermal transfer ribbon and the transferred object are drawn together, resulting in insufficient recording density and sharpness. I'm tired of doing things. Also ;) I below 0℃! ! However, when using the transfer method continuously, the amount of energy applied to the ink of the thermal transfer ribbon is applied to the thermal head itself due to continuous application, and transfer starts over time. The ink is not completely transferred to the transfer object, but some remains on the support of the thermal transfer ribbon. Only good recordings were obtained with problems in hW degree and sharpness.

Based on this, the present invention is designed to apply the melt-1-
ni′! For this 1j10'
li: The answer is 5 times. That is, the state of the ink of the thermal transfer ribbon is added to the [solidification-1δ melting] state.

The relationship with L energy is expressed by differential A, DS
As shown in Figure 2, when measured at temperature C, the solid ink becomes semi-molten at temperatures above the solidification temperature, and when it exceeds the top beak, it becomes almost completely molten and decreases to Iυ. .

In this figure, when the thermal transfer ribbon and the transferred object are peeled off from the adhesive layer, the melting layer exceeds the top peak value, lI
If N is used, complete transfer will not be carried out and problems such as poor transfer efficiency and smearing will occur, so a method is required that will bring the material into a semi-molten state, preferably a solid state. However, in the conventional thermal transfer method, the same ink is applied at room temperature and the ink is melted, and when the ink is still in a molten state, the thermal transfer ribbon and the transferred body are often not peeled off.
The fact that the thermal transfer ribbon and the object to be transferred are separated in the half lδ melting state or solid state in the ideal 11 hour range for transfer is merely a coincidental result depending on the environmental temperature, etc. There wasn't.

Therefore, the present invention provides a method that provides a truly ideal transfer state by forcibly cooling the ink, and lowering the ink to below the top peak value, or even below the solidification temperature, when measured by DSC. This provides a large amount of thermal transfer force to complete the transfer.

・Various J methods have been proposed for forcibly cooling the ink, and any of these methods may be larger than 11. Although not particularly limited, it is possible to thermally cool the ink while the transfer target and the thermal transfer ribbon are in close contact. In order to cool down the ink after it is applied and heated by a RAD etc. until the thermal transfer ribbon and the transfer target are peeled off, it is effective to rapidly cool the thermal head itself and/or the platen itself immediately after application. be.

・When using water or other refrigerant as a means of controlled cooling, one way to quickly cool the thermal head itself is to provide a lateral movement in which the refrigerant circulates inside the thermal head, for example, so that the refrigerant cools immediately after application. There is one sentence for instantly cold sawing the thermal head itself. On the other hand, as a method of cooling the platen itself, there is a method in which the refrigerant is circulated inside the platen by 4 degrees, and the refrigerant is circulated inside the platen immediately after application. In this case, a coolant may be constantly circulated inside the platen, or furthermore, a +8 cooling mechanism may be provided for both the thermal head and the platen, and the cooling mechanism may be used for either or both of them. .

Another method that does not use the above-mentioned refrigerant as a cooling means is to cool the thermal head or platen from the outside. always c
7. Air blowing ports provided adjacent to each other allow the thermal head and/or platen to inject and blow air onto the thermal transfer ribbon. Alternatively, the air outlet may be attached to the platen side, or it may be provided from the platen itself.

(Effects of the Invention) By providing such a cooling means, the cooling time may be extremely short.Of course, thermal transfer ribbons using ink having a softening temperature of 35°C to 120°C can be used. Even with thermal transfer ribbons using inks with lower softening temperatures,
After the ink has softened by -114 mm or melted by ft1, it can be easily lowered to below the temperature at the top peak value of the DSC.

(Example 1) As shown in FIG. 3, a commercially available portable word processor sensor printer using a thermal head 5' modified to circulate a cooling medium inside and cool it immediately after application is used.
Temperature at top peak IIN is 70℃, freezing point 68
Using a thermal transfer ribbon using ink at a temperature of 45° C., recording was performed at an ambient temperature of 45° C.

(Example 2) Instead of the thermal transfer ribbon used in Example 1, the temperature at the top peak value was 771: and the freezing point was 751:.
Using a heat transfer ribbon using ink, the environmental temperature is 4.
Thermal transfer recording was performed at 5°C.

(Example 3) As shown in FIG. 4, in a commercially available 11 Obikawa Wardpress printer modified to circulate cooling water inside the non-metallic platen 10, the temperature at the top peak value was Thermal transfer recording was performed at an environmental temperature of 45°C using a thermal transfer ribbon using ink with a temperature of 70°C and a freezing point of 68°.

(Example 4) In place of the tano-transfer ribbon used in Example 3, the m4 degree at the top peak value was 77°C, and the freezing point was 15'I:
Using a thermal transfer ribbon using ink of
Thermal transfer recording was performed at 5°C.

(Reference Examples 1 to 4) By applying the modifications for cooling in Examples 1 to 4, a commercially available 1J% Obikawa word processor printer was used to prepare a printer under the same conditions corresponding to Examples 1 to 4, respectively. Perform thermal transfer recording with 2. Ta.

Print quality evaluation result Example 1 0 #'f Example 1 × Example 2
◎ Reference Example 2X Example 3 0 Reference Pt Example 3 × Example 4 ◎
Reference Example 4 [Kanji 1 "Using the general printing 1 trial pattern of symbol 1, etc., evaluation was made as follows by visual inspection and with a loupe at 10x magnification.

0 (τε Xiu Good l\　Reading 141 characters θ1 ability X'l'l ut is possible or worse

[Brief explanation of the drawing]

lts 1. Conceptual diagram showing the transfer state when the ink of the thermal transfer ribbon is applied to the object to be transferred. Figure 2 shows the state of [solidification-melting] of the ink of the thermal transfer ribbon using differential scanning calorific value 6.
FIGS. 3 and 4 are conceptual diagrams showing a temperature-heat relationship curve measured by F(DSC), and one specific example of the present invention, respectively. 1... Transferred object 2.3.3'... Ink 5.5'... Circular head (+...
... Transfer to F Bon 7 ... Ribbon cassette: 1 ... Platen Hajime ~ Arata 11 paper 21 copies and i-zu 5. - [Hi11) Win two Lihi 0-Li-jL
Condolences 31 Toyu 4-1] Procedural amendment (method) % formula % 1, Indication of the case 1985 Patent application No. 263858
No. 2, Name of the invention Thermal transfer recording method 3, Relationship with the case of the person making the amendment Patent applicant 26-4 Nishikyokudaimon-cho, Ukyo-ku, Kyoto-shi, Kyoto Prefecture Date of amendment order (shipment date) January 27, 1988 5. Subject of amendment In column 6 of the brief description of the drawings in the specification, the content of the amendment in the second line of page 11 of the specification, "1st" is corrected to "Fig. 1."

Claims (3)

[Claims] (1) After the end of the application pulse, the temperature at which the latent heat of fusion shows the maximum value when the ink heated by the application pulse is measured with a differential scanning calorimeter (DSC) with the transfer target and the thermal transfer ribbon in close contact with each other ( This is a thermal transfer recording method in which the thermal transfer ribbon is peeled off from the object after lowering the temperature to below (top peak value), and the thermal head itself is in close contact with the object to be transferred and the thermal transfer ribbon after the application pulse ends. and/or a thermal transfer recording method characterized in that the platen itself is cooled to forcibly cool the heated melted or softened ink. (2) A thermal transfer recording method according to claim 1, which uses an air blowing mechanism as a cooling method. (3) A thermal transfer recording method according to claim 1, which uses a cooling mechanism using a refrigerant such as water or Freon gas as a cooling method.