JPS6317088A - Printing method - Google Patents

Abstract

PURPOSE:To form a character or image having a high resolving power and a high grade even to paper or a film having an inferior surface smoothness, by transferring the ink of an ink medium activated thermally to an intermediate transfer medium and subsequently fixing said transfer medium to a medium receiving transfer. CONSTITUTION:In such a state that an ink medium 42 and an intermediate transfer medium 45 are laminated, the dye in an ink layer is diffused in the developer layer of the intermediate transfer medium by heat energy from a thermal head 41 to form an image. In such a state that the ink medium, the intermediate transfer medium and a medium 48 receiving a transfer are laminated, the ink medium is separated from the intermediate transfer medium and, at the same time, the intermediate transfer medium is adhered to the medium 48 receiving a transfer by heat or pressure from a roller 49a and fixed thereto (S-part). At a finish time, since the running of the ink medium and the intermediate transfer medium on a supply side is stopped and only the medium receiving a transfer runs, the intermediate transfer medium is cut at a P-part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a thermal transfer printing method for forming an image by controlling the application of thermal energy.

[Conventional technology]

A thermal transfer printing method has been widely put into practical use as a small and low-cost printing method. As shown in Figure 6, the thermal spatula
61. Ink medium 62. Installed in the order of transfer medium 63,
In this method, thermal energy from the thermal head is transferred from the support layer 64 to the ink layer 65 to melt the ink and transfer it to form an image. The ink is a thermoplastic substance colored with pigments, dyes, etc., and the method using melting and adhesion is the heat-melt transfer method, or the ink contains a heat-sublimable dye and the dye is transferred The heat sublimation transfer method is a method of dyeing a medium to form a pattern.

[Problem that the invention seeks to solve]

However, in the conventional technology, when the transfer medium is rough vapor with poor planar smoothness, paper or film with poor chemical affinity with heat-melting ink or heat-sublimable dye, 1. Transfer efficiency was poor and image quality deteriorated. That is, as shown in FIG. 7, when a transfer paper 73 with poor smoothness is used,
Ink that was not in contact with the transfer paper during heat application resulted in poor transfer and remained on the ink medium side (7A), causing a drop in surface quality. In the figure, 71 is a thermal head, and 72 is an ink medium.

Moreover, such a problem becomes very noticeable when the resolution of the transferred dots becomes high, and the incidence of dots that are not completely transferred increases.

Therefore, the present invention was devised to solve these problems, and its purpose is to use paper, which has very poor surface smoothness and poor chemical affinity with ink.
Also to the film 1. The purpose of the present invention is to provide a printing method that can format high-resolution, high-quality characters and graphics.

[Means for solving problems]

The printing method of the present invention comprises a means for applying thermal energy corresponding to an image signal, a thermally activated ink medium, an intermediate transfer medium, and a transfer medium, and after the image signal is transferred to the intermediate transfer medium, the ink medium is transferred to the intermediate transfer medium. , is characterized in that the intermediate transfer medium is fixed to the transfer medium.

[Effect]

The effect of the above configuration of the present invention will be explained in comparison with a conventional method.

1. In the conventional method, when rough paper with poor surface smoothness is used as the transfer medium, when heat is applied from the thermal head, the areas where the ink and the transfer medium are not in contact are covered with activated ink. Because it does not adhere (adhere) to the transfer medium,
When the subsequent ink medium is peeled off from the transfer medium, a transfer failure occurs.

On the other hand, in the method according to the present invention, ink corresponding to the thermal image is attached to an intermediate transfer medium having a very high degree of smoothness, so that the transfer can be performed under ideal conditions.

2 In the conventional method, during the process of peeling off the ink medium from the transfer medium (in other words, the process of fixing the ink to the transfer medium), ink that is not sufficiently attached to the transfer medium is not transferred. There was a phenomenon in which the ink was transferred to the ink medium. This defective transfer phenomenon becomes more pronounced as the surface smoothness of the medium to be transferred is poor and the area of the ink to be transferred is small (such as in high-resolution dot transfer).

That is, in the pulling process of the ink medium shown in FIGS. 8(a) and 8(b), the force acting on the ink to be transferred (82a) is the force exerted by the IPA (support layer 81 of the ink medium and the ink of the ink medium). Adhesive force between layers 82), 'B
There are three types: FC (cohesive force of the ink at the image boundary), and FC (adhesive force between the ink and the transfer medium 83). In the figure, 84 is the point where the ink is attached to the transfer medium, and the ink 82a is completely transferred to the transfer medium (C is FC) F'A
+ Must be IFB. Here, FA and FC are
Proportional to my area, FA=fA-8, FC=fO-8
It is expressed as Here, fA and fC are adhesive forces (adhesive forces) per unit area, respectively, and S is the area of the image. IFB is proportional to the circumference of the image (provided that the ink thickness is constant), and is expressed as FB=fB-J. Here, fB is the cohesive force of the wild goose length and the length of the Jpo circumference.

If the image is a circular dot and the dot diameter is φ, then FA=
・fA・φ” FB=, ・fB・φF C!=
K,・fO・φ2. However, K and 3 are constants.

Therefore, the transcription conditions PC > FA + FB are, ・fC・φ go > Kl・fA・φ20, fB・φ and υ, K, ・fC
>K, ・fA+, ・fB・1A...■.

Here, if the smoothness of the transfer medium is poor, fC in the above equation 0 becomes small, and if the area of the transferred image is small, 1/4 in the above equation 0 increases, so for both of them, It works to lower the transfer efficiency.

On the other hand, in the method of the present invention, when transferring small dots as shown in FIG. This has the effect of reducing /4, and has the effect of greatly increasing transfer efficiency.

〔Example〕

<Example 1> An example of the printing method according to the present invention is shown in FIGS. 1(a) and (b).
) and (c). 11 is a thermal head, and 12 is an ink medium, which consists of a support layer 13 and an ink layer 14.

The ink medium of the present invention can be the same as the conventional ink medium for thermal transfer.

That is, as a support layer, pz'r, pps.

A heat-resistant polymer film such as PEEK, PKE+, or polyamide, preferably with a thickness of 1 to 20 μm. The ink is
The thermoplastic material containing dyes, pigments, etc. preferably has a melting point or softening point in the range of AO°C to 200°C.

As binders for thermoplastic substances, waxes such as natural waxes, petroleum waxes, and synthetic waxes, fatty acid amides, fatty acid esters, EVA, FXEA,
Polyvinyl alcohol, methyl cellulose, carboxin methyl heptylulose, styrene-butadiene copolymer, methyl methacrylic resin, etc. can be used. dye·
The pigment content is preferably 1 to 50 wt%.

The thickness of the ink is preferably 1 liter to 20 microns. In FIG. 1, reference numeral 15 denotes an intermediate transfer medium, which is mainly composed of a thermoplastic organic substance and is a thin film that is transparent or colored as necessary. Melting point or softening point is AQ℃
It is preferable that the temperature is in the range of ~200°C, and the thickness is in the range of 11 to 100 μm. As for the components, waxes, polymers, etc., similar to the above-mentioned ink, can be used alone or in combination, and the viscosity above the melting point or softening point is 5000P8.
It is preferable to make it more than that.

Next, the printing mechanism in this embodiment will be explained.

5 steps 1. The process of transferring an ink medium to an intermediate transfer medium.

As shown in FIG. 1(a), when the ink medium and the intermediate transfer medium are stacked (at the top of the platen 17), the ink is melted by thermal energy from the thermal head and adheres to the intermediate transfer medium (transferred). ). In the figure, part S is the attached part.

5top 2. The process of fixing an imaged intermediate transfer medium to a receiving medium.

As shown in FIG. 1(a), in a state in which the ink medium, intermediate transfer medium, and transfer medium are stacked (at the top of the platen 19), the ink medium is peeled off from the intermediate transfer medium and attached using the previous Eltep. Transferring the ink portion onto the intermediate transfer medium. (IAa in the figure) At the same time, the intermediate transfer medium is transferred to the transfer medium 1 by heat or pressure from the roller 18.
6 and fix it (Sa part).

In the case of transfer by compression, the intermediate transfer medium must be a pressure-sensitive adhesive material, and in the case of transfer by softening or melting the intermediate transfer medium by heat, it is necessary to use a thermoplastic material. In the latter case, the adhesion temperature TA of the ink to the intermediate transfer medium, the temperature of the roller 18, and the temperature of the roller 18 are set so that the ink in the non-recorded area where no thermal image is applied does not adhere to the intermediate transfer medium due to the heat from the roller 18. TB, the adhesion temperature TO of the intermediate transfer medium to the transfer medium is TA)TB)T(:!
The softening points or melting points of the ink and intermediate transfer medium, and the temperature of the roller 18 are appropriately set so that

FIG. 1(b) shows a state in which the fixation of the intermediate transfer medium to the transfer target medium is completed. As shown in the figure, at the end,
The supply side ink medium and intermediate transfer medium stop running,
Since only the medium to be transferred travels (the reverse is also possible), the intermediate transfer medium is cut at portion P in the figure.

The above is the printing mechanism in this embodiment.

Further, the ink medium and the intermediate transfer medium can be supplied separately and overlapped when the thermal image is applied by the thermal head, but as shown in FIG.
．． It is also possible to supply the intermediate transfer medium 23 in a stacked and integrated form.

However, in this case, in order to prevent the ink from adhering (blocking) to the intermediate transfer medium during storage and to ensure that the area to which heat is applied by the thermal head adheres firmly, the boundary between the ink and the intermediate recording medium must be It is necessary to provide a very thin silicone layer on the surface or to perform an interfacial treatment. Since the silicone layer and the interface treatment layer are very thin, they melt and diffuse during thermal imaging, and do not prevent the ink from adhering to the intermediate transfer medium.

Also, 5top j, the process of transferring the ink medium to the intermediate transfer medium, and 5top2. The process of fixing the intermediate transfer medium on which @ is formed to the transfer medium can be performed separately in chronological order as described above, but it can be performed in 8 step 1. and 5t
ep 2. It is also possible to do both at the same time. That is,
As shown in FIG. 1C, when a thermal image is applied by the thermal head (on the upper part of the platen 17), the image is transferred and the intermediate transfer medium is fixed to the transfer medium at the same time. In this case, the intermediate transfer medium can be fixed by any one of the following methods: suppression from a thermal head, thermal stimulation below the ink transfer temperature, heating of the platen 17, or a combination thereof.

<Example 2> In the printing method in this example, the ink medium 32 (
Support layer 33. The ink layer 54) and intermediate transfer medium 35 are the same as in Example 1.

The transfer mechanism of this example will be explained.

5top 1. The process of transferring an ink medium to an intermediate transfer medium.

As shown in FIG. 3(a), when the ink medium and the intermediate transfer medium are stacked (at the top of the platen 37), the ink is melted by thermal energy from the thermal head and adheres to the intermediate transfer medium (transferred). ). In the figure, part S is the attached part.

5top 2. The process of separating the ink medium and the intermediate transfer medium and transferring the ink onto the intermediate transfer medium.

The ink medium and the intermediate transfer medium are separated by the peeling roller 38 and the transfer roller 39 shown in FIG. .

5top 5 The process of fixing the intermediate transfer medium to the transfer medium.

The intermediate transfer medium is fixed to the transfer medium 36 by the transfer roller 39 and platen roller 39a shown in FIG. 3(a) (Sa).

The fixing method may be a method that relies on pressure between the transfer roller and the platen roller, or a method that heats the transfer roller and thermally activates the intermediate transfer medium to fix it.

However, when transferring by pressure, the intermediate transfer medium is a pressure-sensitive adhesive material, and the intermediate transfer medium is softened by heat.
Alternatively, if the material is melted and transferred, it needs to be a thermoplastic material. In the latter case, the adhesion temperature TA of the ink to the intermediate transfer medium is set to the roller 39 so that the ink in the non-recording area that has not been given a thermal image does not adhere to the intermediate transfer medium due to the heat from the transfer roller 39. temperature TB, the adhesion temperature TO of the intermediate transfer medium to the transfer medium
The softening points or melting points of the ink and intermediate transfer medium, and the temperature of the transfer roller 39 are appropriately set so that TA>TB>TO.

FIG. 3(b) shows a state in which the fixation of the intermediate transfer medium to the transfer target medium is completed. As shown in the figure, at the end,
The supply side ink medium and intermediate transfer medium stop running,
Since only the transfer medium moves (the reverse is also possible), the intermediate transfer medium is cut in two parts in the figure.

<Example 3> The printing method in this example is shown in Fig. 4 (a) and (1)).
and (C). 41 is a thermal head, and 42 is an ink medium, which consists of a support layer 43 and an ink medium.

The ink medium of the present invention can be the same as the conventional sublimation thermal transfer ink medium. That is, as a support layer, capacitor paper, PET, PE
A heat-resistant polymer film such as S, PEEE, PIPS, or polyimide with a thickness of 1 to 20 μm is desirable. The ink layer contains sublimable dyes, binders, and additives, and as the sublimable dyes, anthraquinone dyes and other printing dyes can be used. As the binder, oil-based polymers such as phenol-based, rosin-based, polyacid-based, alkyd-based, and alkyl cellulose-based polymers, or water-based polymers such as acrylic acid-based and maleic acid-based polymers can be used. The content of dye in the ink is cL5~150wt4
The thickness of the ink layer is preferably CLI to 20 μm.

In FIG. 4, reference numeral 45 denotes an intermediate transfer medium, which is composed of a color developing layer 46 and an adhesive layer 47. The color developing layer is mainly composed of a polymer that is highly compatible with the dye in the ink layer, and if necessary, a crosslinking agent can be added to improve fixing properties. As the polymer, polyester resin is excellent. The adhesive layer is
It is desirable to have a thermoplastic polymer and/or wax as the main component and to have tackiness when compressed or heated.

That is, waxes such as natural wax, petroleum wax, and synthetic wax, and fatty acid amides.

Fatty acid ester, 1! One or a mixture of fVA, KKA, polyvinyl alcohol, methylcellulose, styrene-butadiene copolymer, acrylic resin, etc. can be used. The thickness of the color developing layer is l:L5~20μ
The thickness of the adhesive layer is desirably from L1 to 30 μm.Also, by selecting the components, one layer can serve as both the color developing layer and the adhesive layer.

Next, the printing mechanism in this embodiment will be explained.

5top1. The process of transferring sublimable ink (dye) to an intermediate transfer medium.

As shown in Fig. 4(a) K, when the ink medium and the intermediate transfer medium are stacked (above the platen A9), the thermal energy from the thermal head causes the pigment in the ink layer to develop into the intermediate transfer medium. Diffuse into the layer and form an image. (A in the diagram) Stop 2. The process of fixing an imaged intermediate transfer medium to a receiving medium.

As shown in FIG. 4(a), an ink medium, an intermediate transfer medium,
In a state where the transfer media are stacked, the ink medium and the intermediate transfer medium are separated, and at the same time, the intermediate transfer medium is attached onto the transfer medium 48 by heat or pressure from the roller 49a (8 parts) Make it stick.

FIG. 4(b) shows a state in which the fixation of the intermediate transfer medium to the transfer target medium is completed. As shown in the figure, at the end,
The supply rabbit's ink medium and intermediate transfer medium stop running,
Since only the medium to be transferred travels (the reverse is also possible), the intermediate transfer medium is cut at the portion tI'iP.

The above is the mechanism of printing with the actual remaining layer.

Also, E]tep1. The process of transferring the ink medium to the intermediate transfer medium and the process of fixing the intermediate transfer medium on which the 5tepl image is formed to the transfer medium can be performed separately in chronological order as described above, but EItepl, and 5t
ep 2. It is also possible to do both at the same time. That is,
As shown in FIG. 4C, when the thermal image is applied by the thermal head (on the upper part of the platen 49), the image transfer and the fixation of the intermediate transfer medium to the transfer medium are performed simultaneously. In this case, the intermediate transfer medium can be fixed by any one of pressing from a thermal head, thermal bias below the ink transfer temperature, heating of the platen 17, or a combination thereof.

Further, the ink medium and the intermediate transfer medium can be supplied separately and overlapped when the thermal image is applied by the thermal head, but as shown in FIG. 5, the support layer 51. Ink layer 52
．． Color developing layer 53. The adhesive layer 54 can also be laminated, ie, the ink medium and the intermediate transfer medium can be laminated and fed onto the Z chamber.

〔Effect of the invention〕

As described above, in the printing method according to the present invention, scratches are formed under conditions with very high transfer reproducibility, that is, on an intermediate transfer medium, and even on a transfer medium with poor optical surface smoothness. Since the transfer efficiency is extremely high since it is necessary to transfer a large area of the intermediate transfer medium all at once, it is possible to form high-quality characters and images with high resolution and speed. Furthermore, the intermediate transfer medium provides excellent fixation of characters and images onto the transfer medium.

[Brief explanation of drawings]

FIG. 1(a), (1)), (((ri) is a diagram showing an embodiment of the printing method of the present invention. FIG. 2 is a diagram showing an ink medium and intermediate transfer used in the printing method of the present invention. Diagrams showing embodiments of the medium.
) and (C) are diagrams showing an embodiment of the printing method of the present invention. FIG. 5 is a diagram showing an example of an ink medium and an intermediate transfer medium used in the printing method of the present invention. FIG. 6 and FIG. 7 are diagrams showing a conventional printing method. Figures 18 (turtle'), (b), and (c) are diagrams showing the forces acting on ink during ink transfer. Applicant Seiko Epson Co., Ltd. and Agent Patent Attorney Mogami ゛ 2 and 1 other person Figure 1 (C) Figure 2 Figure 3 (b) Figure 4 Figure 4 (C) Figure 5 Figure 7

Claims (1)

[Claims] The method comprises a means for applying thermal energy corresponding to an image signal, a thermally activated ink medium, an intermediate transfer medium, and a transfer medium, and the ink of the ink medium activated by the thermal energy is transferred to the intermediate transfer medium. A printing method characterized by fixing an intermediate transfer medium to a medium to be transferred after the transfer.