| 摘要 |
PURPOSE:To enable pressure within the body to be kept constant by preventing change of temperature, in particular, rise of temperature within the body filled with ink. CONSTITUTION:In a writing instrument directly filled with ink 1 within the body 2 to be grasped when writing, the body is formed in such a way that an outer pipe 2b is provided on the outside of an inner pipe 2a to be filled with ink 1 over the generally entire length thereof and a thermal insulation space 7 is defined between the outer pipe 2b and the inner pipe 2a. Also, by providing an outer flowing bore 8 communicating with the thermal insulation space 7 in place in the outer pipe 2b, temperature rise within the thermal insulation space is precluded by the outer air flowing in through the outer flowing bore to be kept constant at all times, whereby heat transfer to the inner pipe to be filled with ink, i.e., transfer of the user's temperature is interrupted with the consequence that rise of inner pressure due to the temperature rise can be prevented. |
