JPH09104172A - Method for forming monochromatic ablation image - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the fading by exposure hard to generate while keeping rational coloring matter removing ratio and contamination excluding properties by adding nitrosophenol or a ferrous complex of nitrosophenol to a coloring matter ablasion film element. SOLUTION: In a coloring matter ablasion recording element formed by a coloring matter layer wherein cyan image coloring matter is dispersed in a polymeric binder is provided on the surface of a support, an independent separate infrared absorbing substance is not contained and nitrosphenol or a ferrous complex of nitrosophenol is combined with the coloring matter layer. Nitrosophenol or the ferrous complex of nitrosophenol added to the coloring matter ablasion film element brings about the enhancement of fading resistance against exposure while keeps rational coloring matter removing ratio (speed) and contamination excluding properties (low Dmin level).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION This invention relates to the use of certain cyan dye stabilizers in single sheet laser dye ablative recording elements.

[0002]

2. Description of the Related Art Recently, a thermal transfer apparatus for obtaining a print from an image generated electronically from a color video camera has been developed. According to one method of obtaining such prints, an electronic image is first subjected to color separation by a color filter. Next, each color separation image is converted into an electric signal. Then manipulate these signals to get cyan,
It generates magenta and yellow electrical signals and transmits these signals to a thermal printer. To obtain a print, a cyan, magenta or yellow dye-donor element is placed face-to-face with a dye-receiving element. The two elements are then inserted between the thermal print head and the platen roller. Heat is applied from the back side of the dye-donor sheet using a line-type thermal printhead. The thermal printhead has a number of heating elements and is heated up sequentially in response to cyan, magenta and yellow signals. Thereafter, this process is repeated for the other two colors. Thus,
A color hard copy corresponding to the original image viewed on the screen is obtained. Details of this method and the apparatus for performing it are described in U.S. Pat. No. 4,621,271.

Another method of using the electronic signals described above to obtain prints thermally is to use a laser instead of a thermal printhead. In such a manner, the donor sheet contains a substance that exhibits strong absorption at the wavelength of the laser. Upon irradiation of the donor, the absorbing material converts light energy into heat energy, which is transferred to the nearby dye, which is heated to its evaporation temperature and transferred to the acceptor. The absorbing material may be present in the layer below the dye, or mixed with the dye, or both. The laser beam is modulated by an electronic signal that is representative of the shape and color of the original image, and each dye is heated and evaporated only in those areas on the receptor that must be present to reconstruct the color of the original object . The details of this method are described in GB-A-2,083,726.

In one of the ablative modes of imaging by the action of a laser beam, an element in which a dye layer composition comprising an image dye, an infrared absorbing material, and a binder is coated on a support is the dye. The image is formed from the side. The energy imparted by the laser drives off at least the image dye at the point where the laser beam hits the element. In ablative imaging, laser radiation causes abrupt local changes in the imaging layer, thus causing the material to be released from the layer. Ablation imaging is another method in that the image dye is almost completely transferred rather than partially transferred by some chemical change (eg, bond destruction) rather than a complete physical change (eg, melting, evaporation or sublimation). It is distinct from material transfer techniques. The usefulness of such ablative elements is determined in large part by the efficiency with which image dye can be removed upon laser irradiation. The transmission Dmin density is a quantitative value of the image dye removal property, and the lower the value at the recording point, the higher the completeness of the dye removal.

Laser dye ablation is useful in the manufacture of graphic arts technology, printing plates, printed circuit boards and masks for producing monochrome transparent images for medical imaging. These masks are used to block light to other materials and, in the case of medical images, to the eyes, thus providing long term exposure. Therefore, photostability of the dye is of utmost importance. Cyan dyes tend to fade in a relatively short period of time, even on moderate exposure to light from a "light table", ie a table with a fluorescent light to illuminate the film through translucent plastic. Films exposed to light from the light table for a week show a clearly visible fading and hue shift towards yellow. Alignment of the film becomes more difficult because yellow is a color with low visible contrast.

US Pat. No. 5,219,823 describes a dye-donor element for laser-induced thermal dye transfer which comprises a dye layer containing a cyanine infrared absorbing material and a ferrous iron complex of nitrosonnaphthol. Has been done. However, the above U.S. patents indicate that ferrous complexes of nitrosonaphthol specifically stabilize cyan image dyes, or such materials can be used in laser dye ablative methods instead of laser dye transfer methods. There is no mention of anything.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a laser dye ablative process which uses a stabilizer for cyan image dyes. Another object of the invention is to provide a stabilizer for cyan image dyes for use in dye ablative recording elements that does not contain a separate, separate infrared absorbing material.

[0008]

These and other objects are directed to a dye ablative comprising a support having on its surface a dye layer in which a cyan image dye is dispersed in a polymeric binder in the absence of a separate receiving element. When the recording element is imagewise irradiated by a laser, the dye layer is combined with a ferrous iron complex of nitrosophenol or nitrosonaphthol, and the dye layer is characterized by the laser used to irradiate the element. Further combined with an infrared absorbing material that absorbs at a wavelength, the cyan image dye does not exhibit substantial absorption at the wavelength of the laser used to illuminate the element,
Irradiating the laser from the dye side of the element, thus imagewise heating the dye layer and ablating it;
Removing the ablated material to obtain an image on the ablative recording element.

Another embodiment of the present invention is a dye ablative recording element which comprises a support having on its surface a dye layer in which a cyan image dye is dispersed in a polymeric binder, the separate infrared absorbing element. A recording element which contains no substance and in which the dye layer is combined with a ferrous complex of nitrosophenol or nitrosonaphthol. In accordance with the present invention, a ferrous iron complex of nitrosophenol or nitrosonaphthol added to a dye ablation film element is resistant to exposure while maintaining reasonable dye removal rates (speed) and stain removal (low Dmin levels). Provides improved fading. The added complex may be in the form of the free salt or in the form of a counterion to the infrared absorbing dye which may be present in the element.
This latter form is advantageous in that it requires less material to be removed before reaching Dmin.
This is because the elimination of the inert counterion to both the stabilizer and the IR absorbing dye reduces the mass of the counterion that must be ablated.

Any ferrous complex of nitrosophenol or nitrosonaphthol can be used in the present invention. In a preferred embodiment, the ferrous iron complex of nitrosophenol or nitrosonaphthol is represented by the following chemical formula.

[0011]

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In the above formula, X and Y are each independently hydrogen,
Acetamido, alkyl or alkoxy having 1 to 4 carbon atoms, nitro, halogen or an atom necessary for completing a condensed or substituted substituted or unsubstituted aromatic ring, provided that Y is an aromatic ring. X is hydrogen, acetamide, alkyl or alkoxy having 1 to 4 carbon atoms,
Is nitro or halogen, and A represents a cation such as ammonium, tetraalkylammonium, alkali metal, 1-alkylpyridinium, and the like.

In another preferred embodiment of the invention A represents tetraalkylammonium, Y is hydrogen,
And X represents methoxy. In yet another preferred embodiment, A represents tetraalkylammonium and either X or Y represents the atoms necessary to provide a fused naphthol ring. Examples of stabilizer complexes that can be used in the present invention are given below.

[0014]

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[0015]

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[0016]

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[0017]

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In a preferred embodiment of the method of the present invention, the infrared absorbing material is an infrared absorbing dye, and it and the ferrous iron complex of nitrosophenol or nitrosonaphthol are present in the dye layer. The dye layer of the dye ablation element of the present invention comprises an ultraviolet absorbing dye such as benzotriazole, substituted dicyanobutadiene, aminodicyanobutadiene or JP-A Nos. 58-62651 and 57-3889.
No. 6, No. 57-132154, No. 61-109049.
No. 58-17450 or German Patent Application Publication No. DE 3,139,156, it may further contain any substance. These can be used in amounts of about 0.05 to about 1.0 g / m ² .

Using the ablation element of the present invention,
Medical images, reprographic masks, printing masks, etc. can be obtained. The obtained image may be a positive image or a negative image. This dye ablation or dye removal method can produce either continuous (photographic-like) images or halftone images. The invention is particularly useful for making reprographic masks used in the manufacture of printed circuit boards and publications.
These masks are exposed to a light source after being placed on a photosensitive material such as a printing plate. The photosensitive material is usually activated only by a specific wavelength. For example, the photosensitive material can be such a polymer that crosslinks or cures when irradiated with ultraviolet or blue light, but does not react with red or green light. In such a light-sensitive material, the mask used for blocking light during exposure is Dmax.
It is necessary to absorb all of the wavelengths that activate the photosensitive material in the region and hardly absorb in the Dmin region. Therefore, for a printing plate, it is important that the mask has a high blue and UV Dmax. Otherwise, the printing plate cannot be developed to provide areas that absorb and those that do not. By using the present invention, it is possible to obtain a mask with improved stability to light for manufacturing a large number of printing plates or circuit boards without deterioration of the mask.

Any polymeric material can be used for the binder in the recording element used in the present invention. For example, a cellulose derivative [eg, cellulose nitrate, cellulose acetate hydrogen phthalate, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose triacetate,
Hydroxypropyl cellulose ether, ethyl cellulose ether, etc.], polycarbonate, polyurethane, polyester, poly (vinyl acetate), polystyrene, poly (styrene-co-acrylonitrile), polysulfone, poly (phenylene oxide), poly (ethylene oxide), poly (vinyl) Alcohol-co-acetals) such as poly (vinyl acetal), poly (vinyl alcohol-co-butyral) or poly (vinyl benzal), or mixtures or copolymers thereof can be used. The binder is about 0.1 to about 5
It can be used at a coating weight of g / m ² .

In a preferred embodiment, the polymeric binder used in the recording element used in the present invention is polystyrene measured by size exclusion chromatography as described in US Pat. No. 5,330,876. The equivalent molecular weight is 100,000 or more. If desired, a barrier layer can be used in the laser ablative recording element of the present invention, as described in US Pat. No. 5,459,017.

To obtain a laser-induced dye ablative image according to the present invention, it is preferable to use an infrared diode laser. This is because there are substantial advantages such as small size, low cost, good stability, good reliability, robustness, and easy modulation. In practical use,
Infrared absorbing materials for dye ablative recording elements (unless the image dye absorbs at the wavelength of the laser), such as the cyanine infrared absorbing dyes described in U.S. Pat. No. 4,973,572, U.S. Pat. 5,256,
506, a separate metal layer, or U.S. Pat. Nos. 4,948,777 and 4,950,6.
No. 40, No. 4,950,639, No. 4,948,
No. 776, No. 4,948,778, No. 4,94
No. 2,141, No. 4,952,552, No. 5,0
No other laser can be used to heat the element without the inclusion of the other materials described in US Pat. Nos. 36,040 and 4,912,083. Laser radiation is absorbed into the dye layer and converted to heat by a molecular process known as internal conversion. Thus, the construction of a useful dye layer depends not only on the hue, transferability and strength of the image dye, but also on the ability of the dye layer to absorb radiation and convert it to heat. The infrared absorbing dye may be contained in the dye layer itself or in another layer combined therewith, that is, in the upper layer or the lower layer of the dye layer. It is preferred that the laser irradiation in the method of the present invention be performed from the dye side of the dye ablative recording element such that the method can be a single sheet process (ie a process that does not require a separate and separate receiving element).

The dye layer of the dye ablative recording element of the present invention may be coated on the support or printed on the support by a printing method such as a gravure method. Any material can be used for the support for the dye ablative recording element of the present invention provided it is dimensionally stable and can withstand the heat of the laser. Such materials include polyesters such as poly (ethylene naphthalate), polysulfones, poly (ethylene terephthalate), polyamides, polycarbonates, cellulose esters, fluoropolymers, polyethers, polyacetals, polyolefins and polyimides.
The thickness of the support is generally from about 5 to about 200 μm. In a preferred embodiment, the support is transparent.

Thermal printers using the above lasers to form images on thermal print media are described and claimed in US Pat. No. 5,168,288. Any cyan image dye can be used in the dye ablative recording element used in the invention provided it is transferable to the dye receiving layer by the action of a laser. The following cyan dyes:

[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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Alternatively, US Pat. No. 4,541,830,
No. 4,698,651, No. 4,695,287
No. 4,701,439 and 4,757,04
No. 6, No. 4,743,582, No. 4,769,3
Particularly good results are obtained with any of the cyan dyes described in No. 60 and No. 4,753,922. The above dyes may be used alone or in combination with another dye. These dyes can be used at a coverage of from about 0.05 to about 1 g / m < ² > and are preferably hydrophobic.

[0032]

The following examples illustrate the invention. Example 1 This example illustrates that the ferrous nitrosophenol complex can be present in the form of the counterion of the infrared absorbing dye. The structures of various substances used in the examples are shown below.

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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On a 100 μm thick poly (ethylene terephthalate) film, nitrocellulose (1000
~ 1500 seconds) (0.604 g / m ² ), UV dye (0.172 g / m ² ), yellow dye (0.284
g / m ² ) and IR dye-1 (0.215 g / m ² ).
And an imaging layer consisting of cyan dyes 1 to 4 (amounts listed in Table 1) were applied to produce control elements. The cyan dye amount was varied to maintain the nominal Status A red density at about 1.5 OD. The element according to the invention was prepared in the same way as the control element, except that IR Dye-2 was added at 0.
It was included in an amount of 312 g / m ² . The reason why the coating amount of the infrared absorbing dye is increased is the change of the counter ion due to the increase of the molecular weight.

A sample of each film element was placed on a light table for a week. The arrangement of these samples was such that one half of each sample was protected from light and the other half crossed the fluorescent area. The fading of the cyan dye is confirmed by X-Ri
te310 type densitometer (X-Rite, Gr
by measuring Status A red absorbance by Andville, MI). The color fading was expressed as a percentage of the reduction in red optical density based on the unirradiated area.
A negative value means an increase in optical absorption. The following results were obtained.

Table 1 Elements Containing IR Dye / Cyan Dye (g / m ² ) Red Optical Density Reduction Rate (%) IR Dye-1 (Control) / Cyan Dye 1 (0.377 g / m ² ) 25 IR Dye-2 / cyan dye ^{1 (0.377 g / m 2)} 3 IR dye 1 (control) / cyan dye ^{2 (0.269 g / m 2)} 22 IR dye-2 / cyan dye ^{2 (0.269 g / m 2)} -2 IR dye -1 (control) / cyan dye 3 (0.161 g / m ² ) 89 IR dye-2 / cyan dye 3 (0.161 g / m ² ) 30 IR dye-1 (control) / cyan dye 4 (0.316 g / m ²⁾ ) 60 IR dye-2 / Cyan dye 4 (0.316 g / m ² ) 3

The above results show that when the infrared absorbing dye containing the ferrous complex counter ion of nitrosophenol according to the present invention and various cyan dyes are used, a remarkable improvement can be achieved in minimizing the decrease in red optical density. It shows that it can be obtained. Example 2 This example illustrates the beneficial effect of adding a stabilizer to an element that does not contain an IR absorbing dye used in the dye ablation method using a red laser. Control Element 2 was made similar to the control element of Example 1 containing Cyan Dye 3, with the exception that IR Dye-
1 did not exist at all. The element according to the invention is
Same as Control Element 2, but with stabilizer S-
1, S-2, S-3 and S-4 were contained at 0.097 g / m ² . As in the case of Example 1, the photobleaching characteristics on a light box for 5 days were measured. The following results were obtained.

Table 2 Elements containing stabilizer Red optical density reduction rate (%) None (Element 2 for control) 88 S-1 36 S-2 42 S-3 20 S-4 50

The above results show that the addition of stabilizers to elements that do not contain IR absorbing dyes significantly improves the photobleaching properties. Example 3 This example illustrates the addition of a ferrous nitrosophenol complex to an ablation element containing an IR absorbing dye. A control element of Example 1 was prepared containing cyan dyes 1 and 3. The elements according to the invention were prepared in the same way as these control elements, except that the stabilizer S-
1 (0.097 g / m ² ) was included. In the same manner as in Example 1, the photobleaching property for one week was measured on the light box. The following results were obtained.

Table 3 Elements containing cyan dye / stabilizer Red optical density reduction rate (%) Cyan dye 1 / no stabilizer (control) 22 Cyan dye 1 / stabilizer S-1 6 Cyan dye 3 / no stabilizer Containing (control) 89 Cyan dye 3 / stabilizer S-1 33

The above results show that the addition of a stabilizer to the ablation element as an independent salt significantly improves the photobleaching properties. Example 4 The four elements of Example 3 were laser ablated to remove all dye in the laser illuminated area. The laser has a focal plane average power of 550 milliwatts 700
Nine milliwatts were used. A 53 cm drum was rotated at 1040 rpm to give an energy of 583 mJ / cm ² . This resulted in an image area that was essentially removed to the base and was only 0.02 higher than the lowest UV D _min achieved at higher power.

The film has a clean removability (ultraviolet light).
Due to its high sensitivity to t), the optical density was measured in the UV range. UV D _min is X-Rite 361T
It was measured with a type densitometer. Status A Red D _min
All values are 0.05 and UVD _max values are all 2.
It was 77 ± 0.11. The following results were obtained.

Table 4 Elements containing cyan dye / stabilizer UVD _min Cyan dye 1 / stabilizer free (control) 0.12 Cyan dye 1 / stabilizer S-1 0.14 Cyan dye 3 / stabilizer free ( Control) 0.12 Cyan dye 3 / stabilizer S-1 0.15

The above results show that the change in UV D _min due to the addition of the stabilizer is extremely small. Therefore, the influence on the speed of ablation (the amount of light required to achieve D _min ) is small. Thus, the addition of stabilizer to the element has no appreciable adverse effect.

[0049]

According to the present invention, the addition of a ferrous complex of nitrosophenol or nitrosonaphthol to a dye ablation film element maintains a reasonable dye removal rate (speed) and stain elimination (low Dmin level). On the other hand, the color fastness to exposure is improved.

Claims (1)

[Claims] 1. When imagewise irradiating a dye ablative recording element comprising a support having on its surface a dye layer in which a cyan image dye is dispersed in a polymeric binder in the absence of a separate receiving element, The dye layer is combined with a ferrous iron complex of nitrosophenol or nitrosonaphthol, and the dye layer further comprises an infrared absorbing material that absorbs at a particular wavelength of the laser used to illuminate the element. Combined, the cyan image dye does not exhibit substantial absorption at the wavelength of the laser used to illuminate the element and the laser irradiation is from the dye side of the element, thus the dye Imagewise heating the layer to ablate it and removing the ablated material to provide the ablative recording requirement. Obtaining an image in the element,
Method for forming monochromatic ablation image.