JPH0441668B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention utilizes a thermal recording head or the like to
The present invention relates to an improvement in a thermal transfer recording method for thermal transfer recording of gradation images and the like.

Structure of conventional example and its problems It has a recording medium and a transfer body having a recording material on one side of a base, and the thermal solubility of at least one of the constituent components of this recording material decreases as the temperature rises. A liquid solvent material having an increasing relationship is brought into pressure contact between the recording medium and the recording material, and the recording material is selectively heated and written by a thermal head, a laser beam, etc., and the recording material is heated. A thermal transfer recording method for selectively transferring and recording onto the recording medium has already been proposed.

According to this type of thermal transfer recording method, unlike the conventionally known melt transfer recording method, the density of the recording material transferred to the recording medium is continuously controlled in response to the rising writing temperature of the recording material. Analog gradation is possible, and when a so-called conventional hot melt wax type melt transfer sheet is used as a transfer material, the analog gradation transfer recording described above is faster (higher sensitivity) than the known melt transfer recording method.
It has excellent advantages such as being able to be transcribed and recorded.

However, in this type of thermal transfer recording method, the recording material is not dissolved by the liquid solvent material in the non-temperature-raising writing control section, and the recording material is not dissolved by the liquid solvent material in the temperature-raising writing control section in response to this temperature increase. The liquid solvent material must be selected so that the recording material is effectively dissolved by the material.

That is, regarding the solubility of liquid solvent materials,
There is a reciprocal relationship between the non-heated part and the heated part.

Therefore, if the solubility of the solvent material is simply selected to be high for the purpose of high-sensitivity operation, the recording material will be dissolved and transferred to the recording medium even in the non-heated area, causing so-called fog transfer in the background of the recorded image. If the solubility is reduced in order to prevent this fog transfer, the recording density of high-density portions of the recorded image will decrease, making high-speed recording difficult.

Selection of a solvent material to overcome such a conflicting relationship requires that the selection of a solvent material be extremely limited due to the correlation with the composition of the recording material, and it is desirable to improve this. It's a place where you can be.

Purpose of the Invention With the above-mentioned difficulties as a background, the present invention aims to improve the above problems, prevent fog transfer, and realize high-density, high-speed, and high-sensitivity thermal melt transfer recording in response to elevated temperatures. The aim is to improve the method.

Composition of the Invention The principle of the present invention is that in the thermal transfer recording method, the liquid solvent material is a main solvent material having a high thermal solubility for at least one of the constituent components of the recording material, and a small auxiliary solvent material. It consists of a liquid mixed solvent material with a solvent material.

The term "liquid" here refers to a state that exhibits fluidity, and is not necessarily limited to a liquid, but also includes a suspended material with a solid material,
It also includes sol, gel, etc.

Description of examples Examples of the present invention will be described below.

The figure is a cross-sectional structural diagram showing an embodiment of the thermal transfer recording method according to the present invention.

A sheet-like transfer body 100 and recording paper 300 as a recording medium are attached to a recording platen 500 made of rubber or metal that is intermittently rotated by a synchronous motor (not shown).
and a known linear thermal recording head 403 in which resistive heating element elements are linearly arranged at regular intervals, and an arrow 501 synchronizes with the line-sequential heating writing of the head 403 by a recording signal from a drive power source 420. By rotating the recording platen 500, the paper is fed at the same speed.

520 is a transfer sheet roll, 540 is a transfer sheet take-up roll, 560 is a recording paper roll, 58
0 is a recording paper take-up roll.

700 is a solvent material container that accommodates the solvent material 200 and a solvent material coater 600 that applies the solvent material to the recording medium surface 321. The coater 600 is movable, and when it moves in the direction of an arrow 602, the solvent material 200 is coated on the recording medium surface 301 as shown in the figure, and when it moves in the direction of the arrow 601, it moves away from the surface 301 and is not coated.

In the following experimental example, the base 1 of the transfer body 100
10 is a capacitor paper with a thickness of 13 μm, and on its surface, NA gravure ink for G-cello made by Sakata Shokai, which uses nitrocellulose as the main binder and carbon black and organic pigments as coloring materials, is applied using a barcoder. A recording material 120 having a thickness of 4 μm was arranged in a layered manner.

The recording head 403 has a heat generating recording section 410 with an array density of resistance heating elements of 4/mm, and a recording platen 500 consisting of a rubber surface roller with a rubber hardness of 65 degrees and a diameter of 24.5 mm. Between,
A sheet-like recording medium 300 made of recording paper with a thickness of 80 μm and a Beck smoothness of 270 seconds was heated at a pressure of 1.43 Kg/cm ^{2 .}
Pressure weld by inserting.

The deformation of the surface rubber of the platen 500 due to this pressure also has the role of adjusting the contact time between the solvent material 200 and the recording material 120.

Selective so-called temperature increase recording control of the recording material 120 via the substrate 110 by the head 403
The main recording speed is per line.
33.3 ms, and the paper is intermittently fed at a sub-scanning density of 4 lines/mm by the rotation 501 of the recording platen 500 in synchronization with this. To record the temperature increase, a recording electric signal is applied to each resistance heating element with an applied power of 0.7 W and a pulse width P _W modulated.

The recording solvent coater 600 uses a sponge-like roller with a diameter of 10 mm, and by moving as indicated by an arrow 602, it comes into contact with the recording paper surface 301 at a distance of about 35 mm from the recording section 410 of the head 403, and coats the solvent material 200. Apply and impregnate.

In order to stabilize the transfer recording operation without being affected by the ambient temperature, the solvent material container 700 and the recording platen 500 may be provided with temperature setting means such as resistance heaters 810 and 811. Further, as shown at 812 in the figure, before the temperature raising writing process, a heating roller is brought into contact with the recording material surface 121, or this roller is brought into contact with the substrate back surface 111 side to set the recording material surface 121 to a predetermined temperature, It is also possible to stabilize the recording operation.

In this way, in the figure, if the solvent material 200 and the recording material 120 are appropriately selected, the recording material 120 in the pressure recording section 220 will be heated to a recording temperature raised from the recording head 403 by the solvent material 200, that is, the pulse width P. The heat-dissolved recording material 130 is melted at a concentration corresponding to _W , and a transfer record 140 is obtained on the surface of the recording medium 301.

In addition, when repeatedly overlapping transfer recording is performed such as full-color transfer recording, the transfer record 140 is cooled to a constant temperature to stabilize the hot melt transfer record, or when a room temperature liquid is used as the solvent material 200. Since the solvent material 200 remaining on the recording medium surface 301 is no longer needed, in order to evaporate and dry it, a cooling device such as an air blower 750 or a solvent drying means is provided, and the solvent material 200 is cooled by the air blower 751 or the like. or evaporative drying.

In the following experimental examples, the temperature of the solvent material 200, recording medium 300, and transfer body 100 before transfer recording in FIG. 1 was all set to 27°C.

[Example 1] As described above, a black gravure ink (Sakata Shokai, for G cello) was prepared by using a 13 μm thick capacitor paper as the base 110, using nitrol cellulose as the main binder, and mixing carbon black as a coloring material.
In the sheet-like transfer body 100 made of a recording material 120 composed of NA-N1000 black ink) with a thickness of 4 μm, the ketone solvent is the main solvent that dissolves the nitrol cellulose binder well. For example, when the solvent material 200 is methyl isobutyl ketone (MIBK, melting point -84.7°C, boiling point 115.9°C), it exhibits high solubility in the main binder.

When thermal melting transfer is performed as shown in Fig. 1 at an operating ambient temperature of 27°C, the pulse width P _W of the recording electric signal is 0 to 0.
At any time of 4 ms, so-called solid transfer recording of black uniformity occurred, and gradation recording was impossible. On the other hand, aromatic hydrocarbons and aliphatic hydrocarbon solvents are auxiliary solvents that hardly dissolve the nitrol cellulose binder. For example, if meluene (melting point -95.0°C, boiling point 110.6°C) is used as the solvent material 200,
When the pulse width P _W was 0 to 4 ms, the melting power was small, the main binder was not thermally melted, and no transfer record 140 was generated.

In order to prevent the so-called fog transfer at P _W = 0 of MIBK, which is a main solvent with high solubility, and to obtain a transfer record 140 with a recording density corresponding to P _W , toluene, which is an auxiliary solvent with low solubility, is used in MIBK. When 4 parts by weight of toluene is mixed with 1 part by weight to form the solvent material 200, when P _W =0, fog transfer is suppressed and the transfer record 140 is not generated.
The recording density of the transfer record 140 increases as P _W increases, and reaches the saturated maximum recording density at P _W = 4 ms, and P _W
We were able to achieve good analog gradation transfer recording that corresponds to

In the thermal melt transfer recording method, as is known, the three primary colors of cyan, magenta, and yellow, as well as the above-mentioned black ink, are added to the substrate 110, and the recording materials 120 of the three primary colors, and furthermore, the four primary colors are placed regularly in a random pattern, and each Either the sheet-like transfer body 100 of three or four primary colors and three or four thermal recording heads 40 corresponding thereto are used to perform overlapping transfer recording in field sequential manner in response to electric signals of the primary colors.
3, and by sequentially overlapping transfer recording corresponding to each primary color electric signal, thermal melting transfer of a full color image can be performed.

An example of the configuration of three primary colors for full-color thermal melt transfer is shown below.

[Example 2] In Example 1, a recording material of 120 mm in thickness was made to a thickness of 4 μm using yellow gravure ink (NA-N260 transparent yellow ink for G cello) using an organic yellow pigment instead of carbon black as the coloring material. In the sheet-like transfer body 100 configured with P _W =0 to
Over 4ms, MIBK records a solid transcription of 140
, and toluene does not produce a transfer record.

Solvent material 2, which is a mixture of 1 part by weight of MIBK, which has high solubility, and 5 parts by weight, toluene, which has low solubility.
When P _W =0, fog transfer does not occur, and the density of the transferred record 140 increases as P _W increases, reaching the maximum saturation density at P _W =4 ms.

[Example 3] Magenta gravure ink (NA for G cello) in which the colorant material in Example 1 was replaced with magenta organic pigment
- N370 red red ink), the recording material is coated with a thickness of 120 mm.
When using the sheet-like transfer body 100 configured to have a thickness of 4 μm, solid transfer recording occurs in MIBK, which has a high solubility, and P W =0 to P _W =0 to toluene, which has a low solubility.
No transfer record 140 occurs for 4 ms.

When using solvent material 200 in which 7 parts by weight of toluene was mixed with 1 part by weight of MIBK, fog transfer did not occur at P _W =0, and the maximum saturation concentration was exhibited at P _W =4 ms.

[Example 4] Cyan gravure ink (NA-
N800 indigo ink), when using solvent material 200, which is a mixture of 1 part by weight of MIBK and 10 parts by weight of toluene, fog transfer does not occur at P _W = 0, and P _W =
Produces good analog gradation transfer recording with maximum saturation density in 4ms.

As described above, according to the thermal transfer recording method of the present invention,
It has the excellent effect of thermal transfer recording using ordinary gravure ink, and full-color image recording can also be performed using the above-mentioned gravure ink.

For this type of full-color recording, the primary color inks mentioned above are sequentially applied to each solvent material 200 on the recording medium surface 3.
01 to perform hot melt transfer recording, but for good full color recording, each solvent material used must be
It is desirable to consider the thermal solubility of the recording material 120 and the recording material 120.

That is, in an actual configuration, for example, as shown in FIG. 1, three to four types of solvent coaters 600 and containers 700 are installed corresponding to the respective solvent materials, and the number of recording materials for each primary color is adjusted. Prior to thermal transfer, a solvent material is applied to the surface of the recording medium, and thermal melt transfer is performed in layers to perform full-color transfer recording using a three-color method or a four-color method.

According to the above examples, as is clear from the weight ratio of the main solvent and the auxiliary solvent, the solubility of the main solvent in the recording material is as follows: Example 1 (black ink), Example 2 (yellow ink), Example 3. (magenta ink) and Example 4 (cyan ink).

Therefore, when the solvent materials of Examples 1 to 4 are applied in the order of black, yellow, magenta, and cyan after each previous solvent material has been evaporated and dried, and thermal transfer is performed, the primary color transfer record that was thermally transferred earlier will be ,
It is easily thermally dissolved by the solvent material applied prior to the subsequent primary color transfer recording, and the preceding and subsequent primary color transfer recordings are well mixed and mixed, allowing full color transfer recording with good color rendering properties.

On the other hand, if cyan, magenta, yellow, and black are layered and thermally transferred in this order, the preceding transfer record is less likely to be thermally melted by the subsequent solvent material, and the advantage is that a high-resolution, full-color transfer record with sharp outlines can be achieved. There is.

In the above thermal transfer recording method, the solvent material 200 is applied to the recording medium surface 301 side, but the solvent material 200 may be applied to the recording material surface 121 side or both surfaces 310 and 121. Also good.

In the above-mentioned full-color thermal transfer recording, the main solvent material MIBK and the auxiliary solvent material toluene, which have approximately the same boiling points, that is, vapor pressures, are used for each primary color recording material, and the solvent materials 2 and 2 are evaporated differently.
Although the thermal transfer was stabilized by preventing changes in the mixing composition ratio of 0.00, the boiling points of the main solvent material and the auxiliary solvent material can also be appropriately made different.

For example, n-hexane (melting point -95.3°C, boiling point 68.7°C) or n-heptane (melting point -90.6°C, boiling point 98.4°C) with a low boiling point and high vapor pressure is used as an auxiliary solvent for the main solvent MIBK (boiling point 115.9°C). use Liquid solvent material 2 applied and impregnated onto the recording medium surface 301
In case of No. 00, the amount of evaporation of the auxiliary solvent is relatively large over time, and as a result, the concentration of the main solvent becomes high.

Therefore, by appropriately selecting the mixing ratio of the main solvent and the auxiliary solvent, the above-mentioned solvent material 200 is applied to the recording medium surface 301 by a single solvent coater 600, and the above-mentioned Example 1 is applied before the solvent material 200 is evaporated and dried. When the primary color recording materials of ~4 are thermally transferred in the order of decreasing solubility in the main solvent in the order of cyan, magenta, yellow, and black, the concentration of the main solvent increases with time, so the concentration of each primary color recording material increases. It has the advantage of being able to perform hot melt transfer.

On the other hand, a solvent material 200 in which, for example, mesitylene (melting point -44.7°C, boiling point 164.7°C), which has a higher boiling point than the main solvent, is selected as an auxiliary solvent for the main solvent MIBK (boiling point 115.9°C) is applied to the recording medium surface 301.
When impregnated, the concentration of the auxiliary solvent becomes relatively high and the concentration of the main solvent decreases over time.

Therefore, a single solvent coater 600 coats and impregnates the surface of the recording medium with a solvent material 200 in which these mixing ratios are appropriately selected, and the primary color recording of Examples 1 to 4 is performed before the solvent material 200 evaporates and dries. There is an advantage that full-color recording can be achieved by thermally transferring materials in the order of black, yellow, magenta, and cyan in the order of increasing solubility in the main solvent.

Note that cyan, magenta,
Full-color recording is also possible using the yellow three primary color method. Further, in the two full-color methods described above, when the solvent material 200 is insufficient due to evaporation or transfer recording, replenishment can be applied to the recording medium surface 301 using a solvent coater as appropriate.

In any case, the above-described relative concentration change method by evaporation of the main solvent and auxiliary solvent has the advantage that full-color thermal transfer can be performed using a single solvent coater and a single solvent material.

The transfer body 100 may also be a so-called melt transfer type transfer body, which is a known hot melt type in which, for example, about 20% by weight of a pigment coloring material, a main binder is carnauba wax, and an adhesive material, a softening material, etc. are mixed therein. Can be used. Aromatic hydrocarbons such as toluene and xylene can be used as the main solvent, and aliphatic hydrocarbons such as hexane and octane can be used as the auxiliary solvent, and a mixed solvent thereof is suitable as the solvent material.

Note that if a translucent film such as polyethylene terephthalate film is used as the sheet-like substrate 110 of the transfer body 100, thermal melting transfer can be performed using a visible or infrared laser beam, etc., without using a thermal recording head as in this embodiment. .

Furthermore, in this example, the solvent material was composed of a mixture of one type of material for each of the main solvent and the auxiliary solvent, but if necessary, these may be composed of multiple types of materials.
Other additives such as surfactants may also be mixed.

Although the solvent material 200 is liquid at room temperature in the above embodiments, it is sufficient that the solvent material 200 is liquid at the time of temperature increase writing control. The auxiliary solvent may be applied in a molten state using a heated roller coater. In this case, since the substrate temperature of the thermal recording head generally has a limit of about 60°C, it is desirable to select the melting point of the solvent material to be 60°C or lower. Note that the coloring material is not limited to pigments, and a dye alone or a mixture of a pigment and a dye may be used in the same manner.

Effects of the Invention As detailed above, the present invention provides a thermal melt transfer recording method in which a liquid solvent material is used as a main solvent material having a high thermal solubility for at least one of the constituent components of the recording material, and as a small auxiliary solvent material. It is a thermal transfer recording method composed of a mixed material with a solvent material, which prevents fog transfer, provides high density and high sensitivity thermal melt transfer recording, and eases the conditions for selecting recording materials, making a great contribution to industry. There is something.

[Brief explanation of drawings]

The figure is a cross-sectional structural diagram of a thermal transfer recording apparatus that implements a thermal transfer recording method according to an embodiment of the present invention. 100... Transfer body, 120... Recording material, 14
0...Transfer record, 200...Solvent material, 300...
... Recording medium, 403 ... Thermal recording head, 4
20... Drive power supply.

Claims (1)

[Scope of Claims] 1. A recording medium, a transfer member having a recording material on one side of a substrate, and a liquid whose solubility for at least one of the constituent components of the recording material increases as the temperature rises. A thermal transfer recording method comprising a solvent material, the recording material is pressed against the recording medium via the liquid solvent material, and the temperature is selectively raised to transfer the recording material to the recording medium. A thermal transfer recording method characterized in that the material is a liquid mixed solvent material of a main solvent material having a high solubility with respect to at least one of the constituent components of the recording material and an auxiliary solvent material having a low solubility. 2. The thermal transfer recording method according to claim 1, wherein the recording material includes a dye material and a binder material, and the binder material is dissolved by a liquid mixed solvent material as the temperature rises. 3. A plurality of primary color recording materials are sequentially layered and thermally transfer recorded, and the primary color recording materials are classified based on different rankings of thermal solubility in the main solvent.
The thermal transfer recording method according to claim 1 or 2, characterized in that thermal transfer recording is performed in a sequentially overlapping manner.