JPH02175292A - Sublimable heat transfer recording medium and heat transfer recording method - Google Patents

Abstract

PURPOSE:To write and heat transfer by heat generation of an ink layer itself by a semiconductor laser by incorporating near infrared ray absorbing substance having absorption capacity in a wavelength range of the semiconductor laser in the ink layer. CONSTITUTION:An adhesive layer 2 is provided on a board 1, and sublimable dye 3 and near infrared ray absorption substance 4 are uniformly dispersed in an ink layer 2 to be contained. The ink layer 2 itself generates heat and can record at a higher speed as compared with a type of heating through a base material by a thermal head, etc., and eliminates a heat resistant smooth layer for holding heat resistance in a recording medium. The near infrared ray absorbing substance 4 contained together with the sublimable dye 3 in the ink layer 2 is an organic compound which exhibits remarkably absorption in 780-900nm of near infrared ray wavelength band, and generates sufficient heat for sublimating the sublimable dye 3 by the radiated energy of a semiconductor laser, etc. The content of the near infrared ray absorber 3 in the ink layer 2 is about 0.1-10.0wt.% with respect to the total weight of the ink layer 2 by weight after the base material 1 is coated with the ink layer 2 and dried.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a sublimation type thermal transfer recording medium, and more particularly to a recording medium and a recording method for performing thermal transfer using laser light.

(Prior Art) As a recording method for so-called video printers that record full-color images based on electricity No. 45 obtained from still video cameras, video cameras, TVs, optical discs, etc.
The dye sublimation thermal transfer method is a powerful recording method among other non-impact printing technologies because it can express density gradation. In the Y1 flower type thermal transfer method, a thermal transfer method using a thermal head is generally known.

(Problems to be Solved by the Invention) However, in the conventional thermal transfer method using a thermal head, the time required to record one pixel is calculated by the difference between head temperature - rise time. It may be slow or futile as it depends on data transfer time etc. Furthermore, even if an efficient heat dissipation design is implemented, there is a limit to the ability to increase the recording speed due to heat accumulation in the head, which poses a problem.

On the other hand, increasing the recording speed can also be achieved by increasing the sensitivity of the recording medium, but increasing the sensitivity of the medium (ink sheet) has a contradictory relationship with the storage stability of the medium. High quality recording media have not yet been obtained.

Various effective methods have been proposed to solve the problem of increasing the speed of thermal transfer recording, among which a method using a laser is known6 [for example.

In, A., Bruce, J., T., Jacobs, J.
^pp1. Photo, En)<,.

3,40(+977)]. This disperses carbon black particles that absorb laser light in the ink layer.

Recording is performed using a single-volume c-Ne laser beam, which is 0.2 J/
A recording density of 0.6 is obtained with an energy of cm2.

Although the sublimation thermal transfer method using such a laser contains carbon black in the ink layer, it is not transferred itself, so colorization is easy. However, if a large amount of carbon black particles are included in an ink layer with a thickness of 2 to 3 μm, the strength of the ink layer and the adhesion strength to the base may deteriorate, and the near-infrared absorption ability of Koeda carbon black is low, so He-
There is a problem in that thermal transfer cannot be performed unless a high energy gas laser such as a Ne laser is used.

The present invention is directed to 1i!, which is associated with increasing the speed of sublimation thermal transfer recording using a 1-item laser. Our goal is to provide a sublimation-type thermal transfer recording medium and thermal transfer recording method that can be recorded with a semiconductor laser and has high storage stability.
It is considered to be I-like.

Means for Solving Section C] The present invention provides a sublimation type thermal transfer recording medium in which an ink layer containing at least a sublimable dye is provided on one side of a substrate. This is a sublimation type thermal transfer recording medium that contains a material, and since the near-infrared absorbing material is sensitive to the wavelength range of a conductor laser, it can be easily generated by light irradiation with a semiconductor laser, and it can be used directly with ink. The layer can be heated to thermally transfer the +ft-quenching dye to the recording medium. Two more inventions are 750-8
In this method, a semiconductor laser having an emission peak at 90 nm is used to irradiate an ink layer containing a near-infrared absorbing substance with light through a base material to obtain a high-quality recorded image at high speed.

According to the above configuration, the ink layer itself generates heat, which enables faster recording than the method of heating via the base material using a thermal head, etc., and also because it maintains heat resistance in the recording medium. A heat-resistant slipping layer, etc., is also unnecessary.

In the present invention, the near-infrared absorbing substance contained in the ink layer together with the sublimable dye has a near-infrared wavelength band of 780 nm-9.
This is a substance that exhibits significant absorption in 0OnI11, and generates enough heat to sublimate a sublimable dye by irradiation energy from a semiconductor laser or the like. Although gas lasers such as He--Ne lasers have a large irradiation energy, it is desirable that the near-infrared absorbing material generate sufficient heat even when irradiated with low energy by a semiconductor laser or the like. Semiconductor lasers have high density pumping and high efficiency, making them excellent for practical use, but their oscillation wavelength range is typically 700 nm.
The near-infrared absorbing material preferably has an absorption maximum in the n+s band, 800 nm band, +000 nm band, etc. More preferably, from the point of view of practicality of the semiconductor laser, 750rv to 890r+++
It mainly absorbs + near-infrared light.

Preferred near-infrared substances include, for example, organic compounds with a molecular extinction coefficient of 30,000 or more, preferably 100,000 or more, such as polymethine. Examples include azulenium-based, biryllium-based, thiopyrylium-based, squarylium-based, phthalocyanine-based, etc.Near-infrared absorber 5101756 (I C1 Company), which has an absorption spectrum as shown in Figure 2, is commercially available as a near-infrared absorber. made)
, near-infrared absorber 51.16510 (manufactured by IC1), which exhibits an absorption spectrum as shown in FIG. 3, can be suitably used.

The content of the near-infrared absorber in the ink layer (1' aim is the weight after drying the ink layer as a base material for 4 times, preferably 0.1 to 10.0% by weight based on the total amount of the ink layer) is about 1 to 5% by weight.If the content is less than 0.1% by weight, heat generation will be insufficient, and if it exceeds 1090% by weight, precipitation may occur on the surface, which is not preferable.

The recording medium of the present invention is characterized by using the near-infrared absorbent described in -F, and the other structure is the same as that of a conventionally known recording medium, but a heat-resistant slipping layer is not required. Other elements related to the present invention will be explained below.

The base sheet used in the construction of the thermal transfer recording medium of the present invention may be any conventionally known material having a certain degree of tensile strength and heat resistance, for example, 1 to 25 μl, preferably 2 to 25 μl.
These include yuzu processed paper, polyester film, polypropylene film, polysulfone film, polycarbonate film, polyvinyl acedate film, etc. each having a thickness of about 8 μl, and preferably biaxially stretched polyester film.

The depth of the ink layer provided on the surface of the base sheet below is 1~
10 μm, preferably 3 to 6 μm, and the sublimable dye in the same layer is preferably one that sublimates at about 100 to 300° C., and is preferably an azo type or anthraquinone type.

Quinophthalone-based disperse dyes are used, specifically Kayalon Fast Yellow, Kayalon Fast Blue,
Known dyes such as Kayalon Fast Red, Seriton Fast Yellow, and Diketone Fast Violet may be used.

Furthermore, as the binder resin for storing the +2 dye in the ink layer, conventionally known binder resins may be used, and celluloses such as nitrocellulose and methylcellulose, polyesters, etc. are suitable. Adjustment of the ink layer and qr can be carried out according to a conventional method.

FIG. 1 is a schematic cross-sectional view showing the structure of the recording medium that is finally obtained. An adhesive layer 2 is formed on the base material IF, and a sublimable dye 3 and a near-infrared absorbing substance 4 are formed in the ink layer 2.
is uniformly dispersed and contained.

To perform thermal transfer recording using the L recording medium, a semiconductor laser is focused to form a beam of a predetermined diameter, a recording speed is set, and the recording medium of the present invention is made to sweat. As a laser light source, 5 outputs are 30 to 1001I+
A W semiconductor laser is preferably used. Considering the recording density, the spot size may be 80 to 100 μ+n, equivalent to about 10 to 12 pels.

The oscillation wavelength of the semiconductor laser is preferably in the range of 750 to 8,900 wavelengths for practical use, but it may be appropriately selected depending on the maximum absorption wavelength band of the near-infrared absorbing substance used. For example, A
Lasers having various laminated structures such as an lGaAs laser and an InGaAsP laser can be used. Further, it is preferable to carry out circular irradiation from the side of the substrate opposite to the ink layer.

〔Example〕

The present invention will be specifically described below based on Examples.

Example 1 A 6μIIIJ5 biaxially stretched PET film (
An ink having the following composition was applied with an applicator so that the ink layer contained 8.3 weight 1i% of the near-infrared absorbing agent, and an ink layer with a dry film thickness of 5 μI was formed on the ink layer (made by Toshi@). Obtained.

7 Stomach [% Binder: Byron + O: + (ill) 15wt% Solvent Toluene-MEK 76 wt% Near-infrared absorber: NARROW BAND INFR
AREDAB SORBER5101755(ICI)2
A synthetic paper-based receiving paper having a polyester-based receiving layer on the surface is overlaid on the ink layer of the recorded recording medium, and a semiconductor laser LTO90MO/MP (wavelength 830 nn+, maximum optical output 100+ oW, A beam of approximately 100 .mu.I in diameter was created by condensing a laser beam (manufactured by BU Corporation) and scanning the beam at a recording speed of approximately 100 KHz. Immediately after, the recording medium and the receiving paper were peeled off and the dot diameter was measured, and dots with a diameter of about 75 to 90 μm were obtained.

Comparative Example 1 In Example 1, an ink having the following composition was prepared by changing the near-infrared absorbent to carbon black having an average particle size of 3 μm, and an ink layer of 5 μl was obtained.

Sublimation dye: C, 1, Disperse Red
57 Stomach [% Binder: Byron 103 (Toyobo) 15 wt
% Solvent: Toluene-ME (1:1) 48% Near-infrared absorber 2 carbon black 30wt% This recording medium does not have sufficient film strength and the ink layer peels off, resulting in thermal transfer recording. That was impossible.

(Effects of the Invention) Since the ink layer of the sublimation thermal transfer recording medium of the present invention contains a near-infrared absorbing substance that is sensitive (absorbed) in the wavelength range of a semiconductor laser, writing by the semiconductor laser due to the heat generated by the ink layer itself, Thermal transfer can be performed, resulting in faster and higher quality recorded images than when using a thermal head. Furthermore, since the thermal head does not come into contact with the medium, there is no need for a heat-resistant slipping layer, which has the effect of reducing the cost of the recording medium.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing the structure of the M flower-shaped thermal transfer recording medium of the present invention, and FIGS. 2 and 3 respectively show near-infrared absorber 5101756 that can be used in the present invention.
(Nil:I, 3 solution) and 5116510 (
FIG. 1 Base material 2 Ink layer 3 Elevating dye 4 Near-infrared absorbing substance Patent applicant Canon Co., Ltd. Representative Tadashi Wakabayashi Figure 1 5116rlO (Book-ES:a)? 'QQS#7blL
No. 5101756 (CHCja 24; Iru 1stji Matamata 8゛7 Tor M2 figure

Claims (4)

[Claims] (1) In a sublimation thermal transfer recording medium comprising an ink layer containing at least a sublimable dye on one side of a base material,
A sublimation thermal transfer recording medium characterized in that the ink layer contains a near-infrared absorbing substance. (2) The sublimation thermal transfer recording medium according to claim 1, wherein the near-infrared absorbing substance is an organic substance having an absorption maximum in a region of 750 to 890 nm. (3) The near-infrared absorbing substance is present in the ink layer at 0.1 to 1
The sublimation type thermal transfer recording medium according to claim 1, characterized in that it contains 0.0 wt%. (4) The sublimation type thermal transfer recording medium according to claim 1 has a
A thermal transfer recording method characterized in that a semiconductor laser having an emission peak at 890 nm is used to irradiate light to thermally transfer a sublimable dye.