Printing plate unit

A printing plate unit to be demountably mounted on a printing plate mounting portion of a plate cylinder comprising:

• a printing plate having a plate portion provided on part of a surface of a sheet formed of a resilient material and engaging projecting ridges projecting on a rear surface side or a front surface side at both end portions in a longitudinal direction and extending in a width direction;
• and
• a printing plate coupling member coupling both end portions of the printing plate formed cylindrically in the longitudinal direction by engaging the both engaging projecting ridges of the printing plate formed cylindrically, wherein
• a length of the printing plate coupling member is larger than a width of the printing plate so that the printing plate coupling member is provided with a projecting portion projecting from the printing plate formed cylindrically in an axial direction, and
• the printing plate unit is fitted to the printing plate mounting portion from one end side, and is demounted from the same one end side by gripping the projecting portion of the printing plate coupling member in a state both end portions of the printing plate formed into a cylindrical shape are coupled to each other by the printing plate coupling member.