Laser engraving apparatus
First Claim
1. A system comprising, in combination, an anilox roller, and an apparatus for preparing the roller for use in a printing process, the apparatus comprising means to support the roller for rotation about an axis and a head (6,7) mounted for movement parallel to the axis including means to direct a laser beam onto the surface of the roller to engrave or expose a series of cell sites (C) around the roller characterised by an acousto-optic modulator (12) positioned in the path of the laser beam and arranged to deflect the beam substantially in the direction of rotation of the anilox roller (2).
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Accused Products
Abstract
An apparatus for preparing a medium for use in a printing process supports the medium (2) for rotation about an axis. A head (6) is mounted for movement parallel to the axis and includes means to direct a laser beam onto the surface of the medium. The laser beam engraves or exposes the series of cell sites (c) around the medium and an acousto-optic modulator (12) positioned in the path of the laser beam deflects the beam substantially in the direction of rotation of the medium (2). In a preferred example the beam tracks the surface of the medium at a speed matched to that of the medium so as to keep the beam stationary on the cell site while that site is being engraved or exposed. The beam may also be deflected to skip backwards or forwards over immediately adjacent cell sites.
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Citations
17 Claims
- 1. A system comprising, in combination, an anilox roller, and an apparatus for preparing the roller for use in a printing process, the apparatus comprising means to support the roller for rotation about an axis and a head (6,7) mounted for movement parallel to the axis including means to direct a laser beam onto the surface of the roller to engrave or expose a series of cell sites (C) around the roller characterised by an acousto-optic modulator (12) positioned in the path of the laser beam and arranged to deflect the beam substantially in the direction of rotation of the anilox roller (2).
- 8. An apparatus for preparing a medium for use in a printing process comprising means to support the medium for rotation about an axis and a head (6,7) mounted for movement parallel to the axis including means to direct a laser beam onto the surface of the medium to engrave or expose a series of cell sites (C) around the medium, said means to direct a laser beam including an acousto-optic modulator (12) positioned in the path of the laser beam and arranged to deflect the beam substantially in the direction of rotation of the medium (2) so that the acousto-optic modulator tracks the surface of the medium at a speed matched to the speed of the medium to keep the beam stationary on a cell site (C) when the site is being engraved or exposed, and wherein the acousto-optic modulator (12) deflects the beam between cell sites (C) at a speed very much greater than the speed of rotation of the medium.
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16. A method of preparing an anilox roller for use in a printing process comprising supporting the roller for rotation about an axis and directing a laser beam onto the surface of the medium from a head mounted for movement parallel to the axis, characterised by passing the beam through an acousto-optic modulato and thereby deflecting the beam substantially in the direction of rotation of the medium.
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17. A method of preparing a medium (2) for use in a printing process comprising supporting the medium for rotation about an axis and directing a laser beam onto the surface of the medium from a head mounted for movement parallel to the axis, the beam engraving or exposing a series of cell sites (C) around the medium, characterised by deflecting the beam in the direction of rotation of the medium so as to track a cell site (C) while the cell site is engraved or exposed, and subsequently deflecting the beam between cell sites (C) at a speed very much greater than the speed of rotation of the medium.
Specification