US 12,187,061 B2
Thermosensitive recording medium and image forming method
Akihiro Taya, Kanagawa (JP); Junji Ito, Kanagawa (JP); Yasuhiro Aichi, Tokyo (JP); Ayano Mashida, Kanagawa (JP); Masanobu Ootsuka, Tokyo (JP); and Yutaka Yoshimasa, Kanagawa (JP)
Assigned to Canon Kabushiki Kaisha, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Aug. 23, 2021, as Appl. No. 17/408,571.
Application 17/408,571 is a continuation of application No. PCT/JP2020/007989, filed on Feb. 27, 2020.
Claims priority of application No. 2019-035534 (JP), filed on Feb. 28, 2019.
Prior Publication US 2022/0024238 A1, Jan. 27, 2022
Int. Cl. B41M 5/34 (2006.01); B41M 5/40 (2006.01); B41M 5/46 (2006.01)
CPC B41M 5/34 (2013.01) [B41M 5/40 (2013.01); B41M 5/46 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A thermosensitive recording medium including a support and a first thermosensitive coloring layer, a first intermediate layer, and a second thermosensitive coloring layer disposed on the support in descending order of distance from the support,
wherein the first thermosensitive coloring layer and the second thermosensitive coloring layer each contain an electron-donating dye precursor, an electron-accepting compound, a radical-polymerizable compound, and a photoradical polymerization initiator, and
the first intermediate layer contains a UV absorber, which is at least one selected from the group consisting of compounds represented by general formulas (1) to (5) and titanium oxide:

OG Complex Work Unit Chemistry
wherein R1 represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, or a halogen atom, n represents an integer of 0 to 4, R2 represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, m represents an integer of 0 to 4, and when R2 is the substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, a plurality of (2-hydroxy-phenyl)-benzotriazole structures are bonded via the alkylene group;

OG Complex Work Unit Chemistry
wherein R3 and R4 each independently represent a hydrogen atom, a methyl group, or a hydroxyl group, R5, R6, and R7 each independently represent a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, and o, p, and q each independently represent an integer of 0 to 4;

OG Complex Work Unit Chemistry
wherein R15 represents a hydrogen atom, a methyl group, or a hydroxyl group, R8 represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, or a substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, r represents an integer of 0 to 4, when R8 is the substituted or unsubstituted alkylene group having 1 to 8 carbon atoms, a plurality of 2-hydroxy-benzophenone structures are bonded via the alkylene group, R9 represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, or a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, and s represents an integer of 0 to 4;

OG Complex Work Unit Chemistry
wherein R10 represents a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, or a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, R11 represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms, a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 8 carbon atoms, or a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, and t represents an integer of 0 to 4; and

OG Complex Work Unit Chemistry
wherein u represents an integer of 1 to 4, when u is 1, R14 represents a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms or a substituted or unsubstituted aralkyl group having 7 to 12 carbon atoms, and when u is 2 to 4, R14 represents a linking group having a valence of u, and
wherein the thermosensitive recording medium is such that an optical reflection density of an image formed in the thermosensitive recording medium with the second thermosensitive coloring layer is 1.34 or more, when the image is formed by an image forming method comprising:
a step (a) of heating the thermosensitive recording medium at 130° C. to thereby cause the first thermosensitive coloring layer to color;
a step (b) of irradiating the first thermosensitive coloring layer colored by the step (a) with a first UV ray having a wavelength of 365 nm to thereby polymerize the radical-polymerizable compound in the first thermosensitive coloring layer;
a step (c) heating the thermosensitive recording medium irradiated with the first UV ray at 160° C. to thereby cause the second thermosensitive coloring layer to color; and
a step (d) irradiating the second thermosensitive coloring layer colored by the step (c) with a second UV ray having a wavelength of 405 nm to thereby polymerize the radical-polymerizable compound in the second thermosensitive coloring layer.