Abstract: Provided is a booklet including: a plurality of leaves 2; a spine 4 that couples bound edges of the leaves 2 via a flexible glue layer 3; and a front cover 5 and a back cover 6 each having at least an entire area of a surface portion continuing to an entire area of a surface portion of the spine 4, wherein a flexural strength of the spine 4 backed by the glue layer 3 is set such that the spine 4 is flexibly deformed inwardly at a near acute angle together with the bound edges of the leaves 2 when center pages of the leaves 2 are spread.

Abstract: In case the seat portion of the inclining chair is inclined periodically, if a supporting shaft to incline the seat portion is arranged away from a position supporting an ischial tuberosity portion of a seated person in an ordinary posture of sitting, an upper body of the seated person makes an up and down movement widely in compliance with a periodical inclining movement of the seat portion, which might cause dizziness due to a vertical shock to the upper body of the seated person.

Abstract: A printing method directed to a plurality of pieces of slip paper which have been bound into a book and to the outer surface, of which ink containing an initiator and either one of coloring matter and a precursor of coloring matter is applied are placed. A printing plate has a through portion through which radiation penetrates and whose shape corresponds to a pattern to be printed. The printing plate is placed ont he stacked slip paper and X-rays are irradiated upon the printing plate fro the above direction so as to print the pattern of a character on each pieces of the slip paper at a desired are thereof.

Abstract: A printing method directed to a plurality of pieces of slip paper which have been bound into a book and to the outer surface, of which ink containing an initiator and either one of coloring matter and a precursor of coloring matter is applied are placed. A printing plate has a through portion through which radiation penetrates and whose shape corresponds to a pattern to be printed. The printing plate is placed ont he stacked slip paper and X-rays are irradiated upon the printing plate fro the above direction so as to print the pattern of a character on each pieces of the slip paper at a desired are thereof.