| 摘要 |
PURPOSE:To provide colliding surfaces being weakly magnetized and having abrasion resistance, buckling resistance and favorable characteristics of being released from an attracted condition, provide the surfaces with a nitride layer conforming to attraction and release characteristics of a member to be attracted, and obtain a long useful life sufficient to endure, 1,000,000,000 times of collisions, by masking an electromagnetic stainless steel blank material, and providing a nitride layer only on colliding surfaces of an attracting member and the member to be attracted. CONSTITUTION:An attracting member and a member to be attracted are formed from a stainless steel having a hardness HV of 1,000. Each of the members is plated with Cu by an ordinary method, is plated with Ni, thereby masking the entire body by the plated layer, then a colliding part on the magnetic pole side is polished to remove the plated layer, and a strong oxide film remaining is removed by an acid treatment. Then, both of the members are subjected to a nitriding treatment, whereby a hard nitride layer is provided only on the colliding surfaces. For enduring 1,000,000,000 times of printing operations, the nitride layer must have a thickness of 50-100mum, the thickness being arbitrarily controlled by regulating the duration of the treatment. |
