Method of making transfer apparatus having vacuum holes
First Claim
1. A method of making a transfer drum for incorporation in a electrostatic transfer apparatus comprising the steps of:
- forming a layer of at least intermediate conductivity material on the surface of a core;
forming vacuum opening means in said core; and
laser drilling in said layer a line of closely spaced small holes communicating with said opening means.
2 Assignments
0 Petitions
Accused Products
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.
20 Citations
22 Claims
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1. A method of making a transfer drum for incorporation in a electrostatic transfer apparatus comprising the steps of:
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forming a layer of at least intermediate conductivity material on the surface of a core; forming vacuum opening means in said core; and laser drilling in said layer a line of closely spaced small holes communicating with said opening means. - View Dependent Claims (2, 3)
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4. A method of making a transfer drum for incorporation in a electrostatic transfer apparatus comprising the steps of:
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providing a core with vacuum opening means; applying to said core, means to prevent a flow of material into said opening means; coating a layer of at least intermediate conductivity material on said core, said layer being partly defined by said flow preventing means; and laser drilling through said layer a plurality of small holes communicating with said opening means. - View Dependent Claims (5, 6, 7)
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8. A method of making a transfer drum for incorporation in a electrostatic transfer apparatus comprising the steps of:
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forming a layer of at least intermediate conductivity material on the surface of a core, said core having vacuum opening means; laser drilling through said layer, into vacuum communication with said opening means, a plurality of generally conically shaped holes. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method of making a transfer drum for incorporation in a electrostatic transfer apparatus comprising the steps of:
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forming a layer of at least intermediate conductivity material on a reflective surface of a core; laser drilling through said layer with a laser beam that reflects off said reflective surface to form a generally conically shaped hole; and forming vacuum opening means in said core in vacuum communication with said hole.
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Specification