Record receiver having plural interactive leaves or a colorless – Having plural interactive leaves
Reexamination Certificate
2000-07-31
2002-11-19
Hess, Bruce H. (Department: 1774)
Record receiver having plural interactive leaves or a colorless
Having plural interactive leaves
C428S913000, C428S914000
Reexamination Certificate
active
06482768
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a laser thermal transfer material in which thermal transfer of an image is performed by irradiation of a laser. More particularly, the present invention relates to a laser thermal transfer material in which a color proof (DDCP: direct digital color proof) or a masking image in the field of printing is formed by irradiation of a laser on the basis of digital image signals.
2. Description of the Related Art
Hitherto, there has been known a thermal transfer recording technique in which a thermal transfer image receiving material and a thermal transfer material having a support on which a color material layer is provided are laminated. The color material layer contains therein a thermally soluble color material layer or a thermally sublimating dye. The laminated thermal transfer image receiving material and thermal transfer material are heated imagewise from the thermal transfer material side by using a heating device which is controlled by electric signals, such as a thermal head, or an electrically conductive head to thereby transfer and record an image onto the thermal transfer image receiving material.
Such a thermal transfer recording technique has characteristics of low noise, being maintenance free, having low manufacturing cost, facilitating coloring, and being capable of digital recording. This technique is therefore utilized in multiple fields such as in various types of printers, recorders, facsimiles, and computer terminals.
On the other hand, in recent years, in the medical and printing fields, there has been a demand for recording systems which have a high resolution and enable high speed recording as well as enabling image processing, i.e., recording systems which enable so called digital recording. However, in the thermal transfer recording system in which a heating device such as a thermal head or an electrically conductive head is used, image resolution of this system is constrained by the layout density of the heating elements of a head. Further, it is difficult to control the heating temperature of the heating elements at a high speed, due to the characteristics of the heating elements. Accordingly, it is difficult to obtain a high resolution image at a high speed.
Thus, one system capable of providing an image with high resolution at a high speed is a laser recording technology which utilizes a light-to-heat conversion action due to the irradiation of a laser. Recently this system has attracted much attention and is being manufactured as a finished product.
In an image forming system using this technology, in particular, the single mode laser is generally used from the standpoint of attaining highly accurate and finely focused beams, and due to such beam quality, a high resolution image is obtained. Moreover, recording speed is also improved such that an image is formed more speedily than in any conventional recording system which uses a heating device such as a thermal head.
However, in laser recording, laser light having a relatively high energy is used in the state that the focus beam diameter of the laser is converged to about 10 &mgr;m. Thus, the laser light is highly efficiently converted to heat, so as to give a far higher heat energy than heating devices such as a thermal head used in thermal recording. Therefore, the temperature of the area irradiated with the laser locally reaches a very high temperature so that a coloring agent (pigment) contained in an image forming layer in this area decomposes thermally. The coloring agent decomposes thermally so that its hue is lost. Thus, an image having a desired density is not transferred onto an image receiving layer on which the coloring agent is to be transferred, thereby resulting in a drop in the density of the formed image.
Furthermore, the coloring material used as the coloring agent is generally a pigment or the like. However, if many pigments are thermally decomposed, they emit a material harmful to human bodies. Accordingly, in recent years, techniques for preventing or reducing the harmful materials have been sought in compliance with a demand for improving working environment or safety.
Incidentally, JP-A Nos. 6-175361 and 10-292144 disclose techniques using an isoindoline pigment with which a sufficient density can be obtained and has excellent dispersability and color-reproducibility. However, the above-mentioned publications do not state that the pigment is used in any high-temperature treating system. Moreover, such a pigment as above has not been used in any thermal transfer material up to the present. The pigment has not been used to prevent a drop in image density accompanying an improvement in heat-resistance.
JP-A Nos. 10-312088 and 10-292144 disclose techniques using C. I. Pigment Yellow or the like, which has excellent dispersability, light resistance and color-reproducibility. Furthermore, JP-A Nos. 10-268570, 10-268571, 10-268572 and 11-65172 state that the above-mentioned pigment is used as a coloring agent of a developer for developing electrostatic latent images, and has excellent heat resistance. However, such a pigment has not been used in any thermal transfer material up to now. It has not been so far made clear whether harmful materials are generated or whether the pigment generates harmful materials and has heat resistance sufficient to avoid thermal decomposition, in particular, in a case in which the pigment is used as a coloring agent of a thermal transfer material through which recording is performed at a very high temperature by converging laser light.
Incidentally, a single mode laser is generally used for laser recording. The laser power thereof is in a relatively low range of about 150 to 200 mW. Therefore, the single mode laser has not reached a satisfactory level with regard to its productivity.
Recently, therefore, a multi-mode semiconductor laser generally having higher power than the single mode laser has been used in order to increase laser power and make laser recording speed high. This multi-mode semiconductor laser has a high power of 1 W or more, thus enabling a considerable increase in laser power of the laser head.
However, there is a problem in that the multi-mode semiconductor laser has difficulties in converging a laser beam in the widthwise direction and thus the laser beam cannot be converged to have a focal beam diameter as low as 20 &mgr;m or less.
Therefore, in fields such as the medical and printing fields, when attempts are made to record a highly accurate image having a sub-scanning pitch of about 10 &mgr;m using the multi-mode semiconductor laser, adjacent beams overlap with each other and overlapping portions are heated excessively, whereby thermal decomposition of coloring agents as described above advances. Thus, a drop in the density of the image is promoted, and/or release of harmful materials is promoted.
Therefore, even if recording is performed using a multi-mode laser having a high power and overlapping adjacent beams as described above, there is demanded a material that is not easily thermally decomposed at high temperatures or a material that does not emit any harmful material even if it is thermally decomposed.
Up to the present, for image-recording using light-to-heat effect resulting from laser radiation, there has not yet been provided any thermal transfer material which has very high heat resistance not causing a coloring agent to be easily thermally decomposed at high temperatures and can give a high-quality image having a high image density. Moreover, there has not yet been provided any thermal transfer material which has high heat resistance, causes neither drop in image density nor image defects, and has such high safety that prevents generation of harmful materials.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the above-mentioned problems in the prior art.
Another object of the present invention is to provide a laser thermal transfer material which does not cause a drop in density based on thermal decomposition
Hatakeyama Akira
Suzuki Tamotsu
Yoshinari Shinichi
Fuji Photo Film Co. , Ltd.
Hess Bruce H.
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