| 摘要 |
<p>PURPOSE: To easily produce a lower cylinder by molding a resin for a video tape recorder with high accuracy so that the processes and production equipments can be decreased compared with a cylinder made of aluminum. CONSTITUTION: This lower cylinder 1 for a video tape recorder is produced by injection molding of a thermoplastic resin, and the area from the part 2 where a tape travels on the side face of the cylinder to the grounding part 3 on the lower face of the cylinder is coated with a conductive coating film 4 to form a circuit. Thus, the circuit of the conductive thin film coating gives enough conductivity to ground the electrostatic charges produced in the part where a tape travels. Therefore, to prepare the resin itself which constitutes the lower cylinder, it is enough to add spherical carbon beads or the like considering a sliding property. By this method, the problem of decrease in the dimensional accuracy such as sphericity which is caused by anisotropic contraction rate by the addition of a long carbon fiber to increase the conductivity can be avoided.</p> |
