Printer having detecting arm for detecting near-end state of paper roll

A printer, comprising:

• a main body having a paper roll container for containing a paper roll in which belt-shaped paper is wound plenty of times;
• a lid rotatably attached to the main body for closing an opening section of the main body through which opening section the paper roll is loaded in the paper roll container;
• a letter printing mechanism which operates when the lid is closed and prints a letter (image) on the belt-shaped paper of the paper roll by pulling out the belt-shaped paper from the paper roll container;
• and
• a detecting arm which detects a near-end state of the paper roll contained in the paper roll container;
• wherein the detecting arm is rotatably attached onto a rear surface of the lid,
• when the lid is closed, the lid is disposed at an approximately vertical position,
• an upper part of the detecting arm is held by the rear surface of the lid as a rotational center,
• the detecting arm is rotated so that the detecting arm protrudes into the paper roll container,
• the rotation of the detecting arm is stopped when the detecting arm contacts an outer circumferential surface of the paper roll contained in the paper roll container, and
• when the paper roll reaches the near-end state, the detecting arm is not stopped by the outer circumferential surface of the paper roll and rotates by a predetermined angle.