JPS62151391A - Thermal transfer recording system - Google Patents

Abstract

PURPOSE:To permit effective recording by effectively utilizing heat energy by a method in which a specific thermal transfer ink is selectively melted or softened on a roll by application of a patterned form of heat or voltage and the periphery of the ink roll is pressingly contacted with a recording medium. CONSTITUTION:The center 11 of an ink roll 1 composed of a thermal transfer ink with a binder containing an amide resin, as represented by the formula (I), where R1 and R2 are each a 1-30C hydrocarbon group, showing an overcooling periphery, is supported by means of a spring 2a. When heat corresponding to a desired printing pattern is supplied to a thermal transfer ink to make up the periphery from a thermal head 3 in contact with the periphery by the action of the spring 2b, the ink is melted or softened in conformity to the heating pattern and at the same time becomes sticky and transferable to recording mediums. Under pressures of a press roll 5 facing the ink roll 1 through a recording medium 4, the thermal transfer ink keeping a patterned sticky state is pressingly transferred to the medium 4 to form a transferred recording image 6.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal transfer recording method that reduces recording costs by eliminating the need for conventionally used thermal transfer materials.

11 Koi The thermal transfer recording method has been widely used recently because it can record on plain paper and the equipment used is compact and noiseless.

This heat-sensitive transfer recording method generally uses a heat-sensitive transfer material formed by coating a sheet-like support with a heat-transferable ink made of a heat-melting binder and a colorant dispersed therein. The conductive ink layer is superimposed on the recording medium so that it is in contact with the recording medium, and heat is supplied from the support side of the thermal transfer material by an external heat generating member such as a printing head, or γ is applied to the conductive support or the ink layer. Pressure is applied to the conductive support or the ink layer itself to generate heat using Joule heat (JP-A No. 58-220795, JP-A No. 58-12790, etc.), and the molten ink is recorded. By transferring it to a medium, a transferred recorded image corresponding to the heat supply shape is formed on the recording medium.

However, in the conventional thermal transfer recording method, a thermal transfer material is used in which a thermal transferable ink layer is formed by a complicated process on a relatively expensive heat-resistant plastic film support, and this Since thermal transfer materials are essentially disposable, they have the disadvantage of increasing the cost of thermal transfer recording. Furthermore, since patterned heat is applied to the above-mentioned heat-sensitive transfer material from the support side, the heat transferable ink layer is heated through the support, resulting in a loss of thermal energy.

In order to reduce the recording cost of thermal transfer recording method,
It is also possible to use an endless belt-shaped or drum-shaped support that can be used repeatedly, coat and form a heat-transferable ink layer on the spot to make a heat-sensitive transfer material, and use it as is for heat-sensitive transfer recording. However, in this case, ink coating 7
Since it is necessary to incorporate the zero mechanism into the thermal transfer device, there is a problem that the device becomes complicated and large.

The main object of the present invention is to eliminate the drawbacks of the conventional thermal transfer recording method mentioned above, maintain various thermal transfer performances, use a compact device, reduce recording cost, and use less thermal energy. It is an object of the present invention to provide a thermal transfer recording method that can be used effectively and efficiently performs recording.

As a result of research for the above-mentioned purpose, the present inventors formed the thermal transfer ink itself with a binder containing a predetermined amide resin having supercooling properties, and formed it into a roll shape, and on the outer peripheral surface of the ink, A compact thermal transfer bag that can directly apply heat or voltage to give a pattern of adhesiveness, and then press and transfer thermal transfer ink onto a recording medium while the adhesive pattern is maintained. While using Toma, the expensive thermal transfer material used in the past is not required, reducing the cost of thermal transfer recording, and eliminating the loss of thermal energy caused by patterned heat supply through the conventional support. It has been found to be extremely effective in achieving the above objectives.

The thermal transfer recording method of the present invention is based on such knowledge, and more specifically, the outer peripheral surface has supercooling property,
The thermal transfer ink is selectively melted or softened by applying patterned heat or voltage to the outer peripheral surface of an ink roll made of a thermal transfer ink whose binder is one containing an amide resin represented by the general formula % below. A step of bringing the outer circumferential surface of the ink roll into contact with a recording medium to suppress and transfer the thermally transferable ink in a melted or softened state according to the pattern onto the recording medium, and a step of smoothing the outer circumferential surface of the ink roll. It is characterized by this.

Hereinafter, the present invention will be described in further detail with reference to the drawings as necessary. In the following descriptions, "%" is used to express quantitative ratio.
``and 1 part'' are based on weight unless otherwise specified.

Figure 1 shows an embodiment of the present invention in which a thermal head is used as a source of heat for melting or softening thermal transfer ink (hereinafter, this heat supply method is referred to as the "thermal head method"). FIG. 2 is a schematic cross-sectional view in the thickness direction of a recording medium shown in FIG.

Referring to FIG. 1, an ink roll 1 made of thermal transfer ink whose outer peripheral surface contains a predetermined amide resin having supercooling properties as a binder is arranged with its center 11 held by a spring 2a, and Rotates continuously or intermittently in six directions.

On the other hand, heat corresponding to a desired printing pattern is applied to the outer circumferential surface from a thermal head 3 disposed on the right outer circumferential surface of the ink roll 1 rotating as described above and in contact with the outer circumferential surface by the action of a spring 2b. When the thermal transfer ink is supplied, the ink melts or softens depending on the heating pattern described above, and at the same time becomes sticky, and becomes transferable to the recording medium. Move upwards in the diagram accordingly.

While the adhesive pattern of the thermal transferable ink corresponding to the heat supply shape is maintained, the outer peripheral surface of the ink roll 1 is transferred to the recording medium 4, which is transferred from the right side to the left side in the figure, at the transfer position. At this time, under the pressure from the pressure roll 5 facing the ink roll 1 with the recording medium 4 in between, the thermal transfer ink that maintains the above-mentioned patterned adhesive state is transferred to the recording medium 4. A transferred recorded image 6 is formed by suppressing the transfer.

After the above transfer process, the ink roll 1 further rotates from the transfer position in the direction indicated by the arrow, and its uneven outer peripheral surface is smoothed by a blade 7 disposed upstream of the thermal head 3 and connected to a spring 2C. The ink scraped off by the blade 7 is collected in an ink reservoir 8.

Next, the configuration of each part shown in the drawings will be explained.

The ink roll 1 has a rotating body shape such as a cylinder or a circle, and at least its outer peripheral surface is made of thermal transfer ink, but it is possible to rotate around the center 11 of the ink roll 1, As long as the necessary pressure can be applied by the spring 2a connected to the center 11, the ink roll 1 may be formed by forming only the thermal transfer ink into the above-mentioned rotating body shape, or it may be made of materials such as metal or resin. A layer of the above ink is formed around the core material to form the ink roll 1.
You can also use it as

The ink that has been melted or softened in a pattern by the application of heat from the thermal head 3 needs to maintain its transferability until it reaches the transfer position upon contact with the recording medium 4 . To this end, the outer circumferential surface of the ink roll 1 is formed using a thermal transfer ink containing a predetermined amide resin as a binder.

By using an amide resin as a binder, the thermal transfer ink can be made into a supercooled thermal transfer ink.

Here, supercooled thermal transferable ink refers to an ink in a melted or softened state that can be transferred to a recording medium even at a temperature below the original melting point or softening point of the ink when it is heated to melt or soften and then cooled. A substance that maintains a sticky state for a certain period of time.

The thermal transfer ink used in the present invention is made by dispersing coloring agents such as dyes and pigments in an amide resin binder that has supercooling properties. The above properties of the supercooled thermal transfer ink are due to the properties of the amide resin itself, which has supercooling properties.

Namely.

A binder with supercooling property is a binder that maintains the molten state for a certain period of time even at a temperature below the original melting point when it is heated to a temperature above the melting point and then cooled from the molten state. say.

In the present invention, no supercooled substance is mixed into the amide resin. In addition, for binders that do not exhibit a fixed melting point, the "softening point by ring and ball method" is used instead of the "melting point" described below.

``Softening'' is used instead of ``melting.''

The amide resin used in the present invention is represented by the following general formula.

The amide resin used in the present invention may be one of the amide resins represented by the general formula below, or may be a mixture of two or more amide resins. Good too.

General formula % Formula % In the above formula, R1 and R2 are hydrocarbon groups, which can be saturated aliphatic, unsaturated aliphatic, aromatic, or those having an aromatic group in the carbon chain, but especially saturated Aliphatics are preferred. R1°R2 has 1 to 30 carbon atoms, and is particularly preferably in the range of 10 to 20 carbon atoms. In the above formula, R1 and R2 may be the same hydrocarbon group, or may be different hydrocarbon groups.

The amide resin used in the present invention has a supercooling time (-) The time required for the amide resin to start to solidify when left at room temperature after being heated above the melting point or softening point to melt or soften. (The same applies hereinafter), the total content of the amide resin represented by the above general formula contained in the binder is
It is preferable that the residual heat transferable ink roll is 5o ball% or more. If the content of the amide resin represented by the above general formula is small, sufficient effects cannot be obtained. The entire binder of the transferable ink roll may be constituted by mixing one or two or more of the amide resins represented by the general formula i1.

The amide resin used in the present invention is synthesized by the reaction of the following general formula.

OOH Monoamine (R2NH2) used in the above reaction
Examples include methylamine, ethylamine, propylamine, stearylamine, tetradecylamine, alinine, paramethylalinine, paraethylalinine, and the like.

Monocarphonic acid (RICO) used in the above reaction
2H) is 1 such as stearic acid.

Examples include lauric acid.

The amide resin used in the present invention is synthesized by mixing and heating one or more of the above-mentioned monoamines and monocarboxylic acids and condensing them. Moreover, the amide resin used in the present invention is 2
It is also possible to mix and use more than one type of amide resin.

Furthermore, it is also possible to add an oil or the like to the interlayer of the amide resin to adjust its supercooling properties, or to adjust the melt viscosity, adhesive strength, etc. by adding elastomers or the like.

As the coloring agent that composes the thermal transfer ink together with the above-mentioned amide resin binder, all the dyes and pigments commonly used for printing or other recording methods, such as carbon black, are used, and these dyes and pigments can be used alone. Alternatively, the content of the colorant used in combination of two or more types is preferably 1 to 40% with respect to the above ink.

As mentioned above, the amide resin binder.

The supercooled thermal transfer ink composed of a colorant and an additive preferably has a melting point or softening point of 40 to 20.
The temperature is about 0°C, more preferably about 50 to 180″C, and the supercooling time is preferably set to about 0.1 seconds to 100 seconds, more preferably about 0.1 seconds to 50 seconds. Preferably it is 0.1 seconds or more and 10 seconds or less.

When the melting point or softening point of the ink is lower than 40"C,
This causes a decrease in the storage stability of the ink roll l and staining of the non-printing area of the recording medium5.On the other hand, when the melting point or softening point is 200°C
If it is higher, a large amount of thermal energy will be required to melt or soften the ink.

In addition, if the supercooling time is shorter than 0.1 seconds, it will be difficult to maintain the melted or softened state after the heat application process is completed until the transfer process to the recording medium.
If it is longer than 00 seconds, the Q image immediately after being transferred to the recording medium will lack stability.

The supercooling time is the raw material monocarboxylic acid.

It can be adjusted by changing the type and mixing ratio of monoamines, or by mixing a plurality of amide resins represented by the above general formula.

To obtain the ink roll 1 used in the present invention.

For example, the above-mentioned amide resin, colorant, and additives are melt-kneaded using a dispersion device such as an attritor to obtain a thermal transfer ink, and then molded into the desired shape of a rotating body using a mold or the like, using a core material as necessary. Form.

In order to prevent the melted or softened ink from the ink roll 1 from adhering to the thermal head 3, the ink roll 1 is
A metal soap or the like may be added as a component of the heat-melting ink, or fine particles such as a wax resin having a high melting point may be added as a filler.

It is also possible to use ink rolls l having a plurality of different tones for color recording.

The thermal head 3 is a member that supplies heat to the outer circumferential surface of the ink roll 1 described above according to a desired print pattern.

As this thermal head 3, a conventional thermal head can be used as is, but in order to prevent the melted or softened ink from the ink roll 1 that comes into direct contact with it from adhering, silicone resin is used in the heat generating part of the thermal head 3. Coatings such as these may also be applied.

In applying heat by the thermal head 3, as long as the outer peripheral surface of the ink roll 1 and the thermal head are in sufficient contact to apply heat in a desired pattern, the applied pressure is 2 K g/
cm2 or less, and the applied pulse width is 015 to 5
m5ec conditions are preferably adopted.

By changing the amount of heat applied by the thermal head 3, it is also possible to change the amount of ink transferred to the recording medium 4 and obtain so-called half-tone recording on the recording medium.

As the pressure roll 5, either an elastic roll whose surface is made of various rubbers, resins, etc., or a rigid roll whose surface is made of metal or ceramic cap can be used.

This pressure roll 5 and +ii7'Is ink roll 1
The pressure applied to the recording medium 4 between
0 Kg/cm, more preferably 1 to 5 Kg/cm. In order to ensure sufficient adhesion of the thermal transfer ink to the four parts of the surface of the recording medium with poor surface smoothness, it is preferable that the pressure be higher.

The distance between the transfer position where the pressure roll 5 faces the ink roll 1 and the above-mentioned thermal head 3 is such that the thermal transfer ink constituting the outer peripheral surface of the ink roll 1 maintains a melted or softened state in a desired pattern. The interval is set as possible.

The blade 7 is a member that smooths the outer peripheral surface of the ink roll 1, which has become uneven due to the transfer process, by scraping the ink.

This smoothing may be performed using a member such as a heating roll that heats the outer circumferential surface to some extent and melts or softens it again, as will be described later.

The outer peripheral surface of the ink roll 1 whose diameter gradually decreases due to smoothing by the blade 7 is connected to the recording medium 4, the thermal head 3, and the blade 7 to continue thermal transfer recording. It holds each of the above members in a state where necessary contact can be maintained.

In the above, an embodiment of the present invention has been described in which a thermal head method is used, that is, a thermal head is used as a heat source in the heat application process, but the present invention can be applied similarly when a laser beam or other heat source is used instead of the thermal head. It is easy to understand that this can be done.

Separately, as shown in FIG. 2, in place of the thermal head 3 shown in FIG. 1, which is a patterned heat supply means, a recording electrode 3a, which is a needle-like or multi-stylus-like electrode, is used. It can also be used in combination with the conductive drum 9.

Referring to FIG. 2, low resistance layer 91 (specific resistance lO~10
A recording electrode facing the ink roll 1 is attached to the low resistance layer 91 of the conductive drum 9, which is formed by providing a metallic conductive layer 92 having higher conductivity on the conductive drum 9 (4Ωcm). The recording electrode 3 a is connected via a power source 10 to a return electrode 12 which is in contact with a metallic conductive layer 92 .

In the configuration shown in FIG. 2, heat is applied in a pattern to the outer peripheral surface of the ink roll 1 by Joule heat generation in the low resistance layer 91 directly under the recording electrode 3a. Since the electrode 3a does not come into direct contact with the surface, there is less dirt on the electrode 3a, and the metal conductive layer 92
It has the characteristic that the surface can be easily cleaned.

The other configuration is that the above-mentioned heating roll 7a is used instead of the plate 7.

The configuration is similar to that shown in FIG.

FIG. 3 shows another embodiment using the recording electrode 3a.

Referring to FIG. 3, a recording electrode 3a and a large-area return electrode 12a are in direct contact with an ink roll 1a made conductive by dispersing conductive fine particles (not shown). The configuration shown in FIG. 3 is similar to the configuration shown in FIG. 2, except that the outer peripheral surface of the conductive ink roll 1a directly below the recording electrode 3a itself generates Joule heat and melts or softens in a pattern.

As described above, according to the present invention, a pattern of heat or voltage is directly applied to the smooth outer peripheral surface of the ink roll, which has an outer peripheral surface made of thermal transferable ink using a predetermined amide resin as a binder. A thermal transfer recording method is provided in which, after adding the ink, the ink in a melted or softened state according to the pattern is transferred onto a recording medium under pressure.

Since the recording method of the present invention uses a predetermined amide resin as a binder for the thermal transfer ink, the supercooling time is
In other words, the adhesive retention time can be adjusted appropriately. Therefore, according to the recording method of the present invention, efficient recording without waste can be performed.

Furthermore, according to the recording method of the present invention, while using a compact thermal transfer device, the expensive thermal transfer material used in the past is not required, and the pattern can be printed directly on the thermal transfer ink (without using a support). By supplying such heat, recording costs can be significantly reduced in terms of material and energy costs.

Furthermore, according to the present invention, it is possible to obtain high-quality printing even on low-smoothness recording media, and it is also possible to obtain halftone recording.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

L direct Amide resins A and B were synthesized according to the formulations shown in Table 1 below.

Table 1 (Numbers are equivalent) The synthesis method was as follows. Namely, the mixture was placed in a four-eye, nine-bottomed flask equipped with a thermometer, mechanical stirrer, dehydration tube, and nitrogen blowing tube, and while purifying the nitrogen, The temperature was maintained at 180°C for 5 hours, and then the pressure was reduced to 100 mmHg and the reaction was carried out for 1.5 hours to synthesize amide resins A and B.

Next, to 100 parts of each amide resin, 10 parts of nigrosine dye was added as a coloring agent for 1 fL while heating at 110°C.
i Mix the thus obtained thermal transferable ink into a 10 mmφ
The ink roll 1 was formed into a cylindrical shape with a diameter of 60 mm centered around a core material made of resin. The softening temperatures of amide resins A and H are shown in Table 2.

Furthermore, the thermal transfer device shown in FIG. 1 has a distance of 1.5 cm between the thermal head 3 and the transfer position where the pressure roll 5 faces the ink roll 1, and the entire device is compactly constructed. By directly applying heat to the outer peripheral surface of the ink roll 1 using a thermal head, the thermal transfer ink softened in a pattern is applied between the ink roll 1 and the pressure roll 5 under a linear pressure of I K g/cm While applying pressure of
A recorded image was formed by transferring it to old quality paper. Table 2 shows the pulse width of the applied pulse applied to each amide resin.

Table 2 The recorded images thus obtained are visually good in print quality such as print density, transferability, and elucidation, and the recording cost is lower than that of a thermal transfer recording method using a conventional thermal transfer material. Thermal energy consumption was also low.

[Brief explanation of drawings]

1 to 3 are schematic sectional views in the thickness direction of a recording medium showing actual embodiments of the thermal transfer recording method of the present invention, respectively. FIG. 1 is an embodiment using a thermal head, and FIG. 2 is a recording medium. Embodiments using a combination of electrodes and conductive drums,
FIG. 3 shows an embodiment using recording electrodes. 1-------------- Ink roll, 11-------------
Center of ink roll, 2 a, 2 b, 2 c
----------Spring, 3-------------1---------Thermal head, 3 a---------
1---------Recording electrode, 4--------1--
−−−−−−−−−−−−Recording medium, 5−−−−−−−
−−−−−−−−−−−−1 pressure roll, 6−−−−
-----------1---------Transfer recorded image, 7-
−−−−−−−−−−−−−−−−−−−−Blade,
7 a--------------- One heating roll. 8-------------------------- Ink sump, 9---------------1 Conductive drum , 91------------
---Low resistance layer, 92--------
--- Monometallic conductive layer. 10-----------1-----------Power supply, 1
2------------------1------Return trip'ton pole.

Claims (1)

[Claims] The outer circumferential surface of an ink roll is made of a thermal transfer ink whose outer circumferential surface has supercooling properties and whose binder is an amide resin represented by the following general formula. A step of selectively melting or softening the thermal transfer ink by applying a voltage, bringing the outer peripheral surface of the ink roll into contact with a recording medium, and press-transferring the thermal transfer ink in a melted or softened state according to the pattern onto the recording medium. 1. A thermal transfer recording method comprising: a step of smoothing an outer peripheral surface of an ink roll; and a step of smoothing an outer circumferential surface of an ink roll. R_1CONHR_2 [In the above formula, R_1 and R_2 are hydrocarbon groups having 1 to 30 carbon atoms]