A writable recording medium having reduced jitter, improved performance on repeated reproduction, improved light resistance, and sensitivity controllability is disclosed, in which a light-absorbing layer thereof contains (D-1) a cyanine dye having an absorption band in the wavelength region of light for recording or reproduction, (D-2) a cyanine dye having an absorption band in a shorter wavelength region than that of cyanine dye (D-1) and having a smaller absorption than that of cyanine dye (D-...

Provided is a recording medium comprising a base material, and an ink-receiving layer thereon containing a pigment having an aggregated-particle diameter of from 0.5 to 50 .mu.m and a binder, wherein said ink-receiving layer has a value of BET specific surface area/pore volume within the range of from 50 to 500 m.sup.2 /ml.

A recording medium comprising at least one boehmite-containing porous layer on a substrate, wherein the porous layer has pores having a pore radius of from 1 to 30 nm in a pore volume of from 0.3 to 1.2 ml/g, pores having a pore radius of from 10 to 30 nm in a pore volume of from 0.2 to 1.0 ml/g and pores having a pore radius of from 30 to 100 nm in a pore volume of not more than 0.3 ml/g, and the b-axis of a boehmite crystal is oriented vertically with respect to the surface of the substrate.

A filtration medium made from a plurality of solid fibers aligned in the same direction and packed and bundle together and compressed at a portion thereof by a retainer member, and a displacement member disposed inside the packed fibers forming close packed aligned fibers defining a fluid flow passages between the fibers having a cross-sectional area capable of retaining particles from a fluid passing therethrough.

A recording medium is provided which is constituted of a base material and an ink-receiving layer formed on the base material and containing alumina hydrate of a boehmite structure, or is constituted of a fibrous material and alumina hydrate of a boehmite structure incorporated therein. The alumina hydrate in the ink-receiving layer or the fibrous material has an interplanar spacing of (020) plane of exceeding 0.617 nm but not more than 0.620 nm, and crystallite size in a direction perpendicular...

Acid can be generated by exposing a mixture of a superacid precursor and a dye to actinic radiation of a first wavelength which does not, in the absence of the dye, cause decomposition of the superacid precursor to form the corresponding superacid, thereby causing absorption of the actinic radiation and decomposition of part of the superacid precursor, with formation of a protonated product derived from the dye, then irradiating the mixture with actinic radiation of a second wavelength, thereby ...

Acid can be generated by exposing a superacid precursor to actinic radiation effective to generate superacid from the superacid precursor and heating the superacid in admixture with a secondary acid generator capable of undergoing thermal decomposition to produce a secondary acid. The superacid catalyzes decomposition of the secondary acid generator, thus increasing the quantity of strong acid present in the medium. The resultant secondary acid can be used to effect a color change in an acid-sen...

A cross-linked flexible sponge absorbent medium containing substantially uniformly distributed fibrous reinforcement is prepared under such conditions that swelling of the sponge is controlled to a water retention value of 2 to 6; and simultaneously or subsequently, the cross-linked sponge is reacted with a reagent which introduces functional groups into the modified cross-linked sponge. There is also provided apparatus having an inlet for liquid, an outlet for liquid so as to define a path for ...

A process for producing an image uses an imaging medium comprising an acid-generating layer or phase comprising a mixture of a superacid precursor, a sensitizing dye and a secondary acid generator, and a color-change layer comprising an image dye. The sensitizing dye has first and second forms, the first form having substantially greater substantial absorption in a first wavelength range than the second form. The superacid precursor is capable of being decomposed to produce superacid by radiatio...

A recording medium, showing sufficient resistance to contamination and having excellent reproducing characteristics, comprises a film provided on a surface thereof and this film comprises a copolymer formed by polymerizing a composition which comprises a compound A having a (meth)acryloyl group and a reactive antistatic agent B having a quaternary ammonium salt group, an alkylene glycol chain, a hydrocarbon group of which carbon number is four or more and a copolymerizable group.