Lithographic imaging with printing members having enhanced-performance imaging layers
AssigneePresstek, Inc.
InventorThomas E. Lewis
Life of this patent
Estimating the term…
Abstract
Lithographic plate constructions include imaging layers having dispersed therein a radiation-scattering material and a radiation-absorbing material, both of which cooperate to increase the overall absorption of radiation in that layer. The radiation-scattering material may be in particulate form, the particles reflecting the imaging radiation from their surfaces. The use of particulate scattering material within the imaging layer creates a highly porous matrix that favors deep penetration of the imaging radiation and mechanical locking of the imaging layer to one or both adjacent layers. The scattering material may also be chosen also for its ability to chemically bind with an adjacent layer to increase intercoat adhesion.
Claims35
A method for imaging a lithographic printing member, the method comprising the steps of:
- a. providing a printing member comprising a first layer;
- an imaging layer over the first layer, the imaging layer comprising a polymeric material and, dispersed therein, a radiation-scattering material and a radiation-absorbing material;
- and a topmost layer, the topmost layer and the first layer having opposite affinities for ink or a liquid to which ink will not adhere;
- b. selectively exposing at least a portion of the printing member to laser radiation in a pattern representing an image so as to substantially ablate the imaging layer, thereby removing or facilitating removal of the topmost layer;
- and
- c. cleaning the printing member to remove remaining portions of the imaging layer and the topmost layer where the printing member received radiation.
A lithographic printing member comprising:
- a. a first layer;
- b. an imaging layer over the first layer, the imaging layer comprising a polymeric material and, dispersed therein,
- a radiation-scattering material, and
- a radiation-absorbing material;
- and
- c. a topmost layer,
- the topmost layer and the first layer having opposite affinities for ink or a liquid to which ink will not adhere.
Dependencies are inferred from the claim text.