| 摘要 |
To a lower part of a housing 20 of a development unit 3a, a cover 21 is detachably fitted by using snap fittings 40. To a fitting surface 41a of the housing 20 and a fitting surface 41b of the cover 21, sponges 43a and 43b, respectively, are attached and fixed all around them. In a state in which the snap fittings 40 are engaged and thereby the housing 20 and the cover 21 are fixed to each other, the sponges 43a and 43b are in contact with each other and compressed, whereby air-tightness of a fitting part 45 is secured. |
