Method of making transfer apparatus having vacuum holes
US5119550A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 19, 1991 |
| Grant date | Jun 9, 1992 |
| Priority date | — |
| Expiry date | Feb 19, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49117
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A transfer apparatus includes a transfer member, for example, a transfer drum with a line of small closely spaced laser drilled vacuum holes to hold a receiving sheet to the drum surface. The transfer drum is formed by forming a layer of at least intermediate conductivity material on the surface of a core, forming at least one vacuum opening in the core and laser drilling in the layer a line of closely spaced small holes communicating with the opening. In one embodiment, a short focal length lens focuses a laser beam near the surface of the layer, which beam spreads below the surface to form a conical hole. The conical hole helps maintain the continuity of a transfer field while being free from clogging.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.