| 摘要 |
PURPOSE:To make transcription from a core to a film and copying by dust restrainable, by forming a core surface into such one that maximum roughness Rt is less than the specified value and has regular unevenness whose center line mean roughness Ra is within the specified range. CONSTITUTION:A core surface is formed into such one that maximum roughness Rt is less than 10mu and has regular unevenness whose center line mean roughness Ra is within the range of 0.2-2mu. Here, when Rt>10mu or Ra>2mu is the case, it is undesirable because the unevenness itself on the core surface is transferred, and when Ra<0.2mu is the case, there is not transcription from the core itself but dust sticking to the core surface is protruded out of the flat core surface, whereby copying from the dust happens there. At the range of Rt<=10mu and 0.2mu<Ra<=2mu, the transcription from the core surface is almost nothing, if any, it is as negligible as small, so there is no problem on this matter, and that even if minute dust sticks to the core surface, it has been buried in concavities of the regular unevenness, so that if pressing force is imposed on from the film side, copying from the dust is prevented from occurring.
|
