Analysis of Heat-developed Dry Non-silver Imaging Products and Technology (8)

Coupler

The colorimetric nature of couplers is the most important property. However, the sensitivity and stability of TA paper are also very important. The basic structure that can satisfy these characteristics is an active methylene compound that is classified into a chain compound and a cyclic compound. From the absorption spectrum of dyes composed of a diazonium salt and an active methylene compound, a yellow dye can be obtained from the upper diazonium salt and the chain active methylene compound 3, and the middle diazonium salt and the cyclic active methylene compound 4 can be obtained. Obtain the product dye (as shown below). The yellow dye has a molar absorption coefficient (ε) of about 30,000 and a product dye of 35,000 to 45,000.

UV absorber precursor

The UV absorber precursor is an indispensable functional material for the high quality of TA paper and can improve light resistance and light coloration in non-image areas. By setting the UV absorber layer in the TA paper, the photodegradation rate of the diazonium salt in the middle layer is slowed down. Accordingly, ultraviolet rays that do not absorb 365 nm during recording are developed, and an ultraviolet absorber is generated under the light source such as a fluorescent lamp or sunlight after the image is formed. technology.

Since the hydroxy group of the benzotriazole ultraviolet absorber 11 in the figure below is substituted by etherification, esterification, or the like, it cannot bind intramolecular hydrogen in the benzotriazole ring, and therefore the absorption in the vicinity of 350 nm disappears. The benzenesulfonyl group as a protective group 12 causes photodegradation of homolytick radicals due to light, but also efficiently performs photoreaction by the coexistence of a hydrogen donor.

The UV absorber precursor 13 in the figure below can highly control the photoreaction and its photoreaction speed is 100 times higher than the sulfonate protecting group 12 (as shown below). The protecting group uses 2-hydroxyphenylethylene carboxyl group and the hydroxyl group attacks the carboxyl group intramolecularly to remove the coumarin compound and generate an ultraviolet absorber. 13 is highly functional in that the coumarin compound functions as another one molecule of an ultraviolet absorber.

TA thermal printing equipment and consumables market:

The TA-type thermal printer was developed by Fujitsu in 1994 and sold its special photo paper TA paper. The system is surprising in the presentation of continuous tones. The finished product is not only resistant to water and weathering, but it is not a problem for long-term preservation. Together with the special TA photo paper, it can be supplied cheaply, attracting more and more electronic imaging companies to start developing this type of product, including Canon, Sony and Olympus.
Fujitsu has been making unremitting efforts in this area and has launched many brands, as shown in the table below. Due to the dramatic improvement in image quality and storage performance of the new model Printpix CX-400 print photos launched in 2002, Fujifilm used "Printpix" to rename their series of thermal printers.