To provide a supporting structure, a driving force transmission mechanism, and a liquid injection device, capable of being reduced for noise.
A washer 28 is urged with an end of the coil spring 29, and brought in contact with a bottom surface 24a of a recess 24 in an upper case 21. The washer 28 retains the end of the coil spring 29. The washer 28 slides with the coil spring 29 rotating with a spur gear, and rotates with the center at an axle 27. Thereby, the noise occurred by contact with the upper case 21 for the coil spring 29 can be reduced. Since the washer 28 is formed to be able to rotate with the coil spring 29, the friction of the washer 29 with the coil spring 28 can be reduced compared with the case where the washer 28 is fixed to the upper case, then the noise can be more reduced.
TAKAHASHI MASARU
TOJO SEIJI
HARADA SHUHEI
Makoto Onda