| 摘要 |
PROBLEM TO BE SOLVED: To prevent wrong detection of a lack of ink caused by dust, smudge, etc. stuck to the outside surface of a detecting part. SOLUTION: The detecting part 40 of an ink cartridge 1 has a light transmitting properties, including a space which communicates with an ink tank where the ink is stored. Also a part to be detected 71 of a sensor arm 70 with light stopping properties is arranged in the internal space. The detecting part 40 is formed at a position held between a light emitting part 13a and a light receiving part 13b of a sensor 13. A spherical plano-concave lens 12 which widens the width of a bundle of rays by refracting the bundle of rays emitted from the light emitting part 13a is placed between the light emitting part 13a and the detecting part 40. Moreover, a curved surface 41a projecting outside is formed at a part where the bundle of rays passing through the spherical plano-concave lens 12 passes on an outside surface of the detecting part 40. The width of the bundle of rays passing through the spherical plano-concave lens 12 is narrowed by the curved surface 41a. COPYRIGHT: (C)2008,JPO&INPIT |
