Migration imaging, optionally with dyes or pigments to effect bleaching

A method of migration imaging using an imaging element with a thermoplastic imaging surface layer, said method comprising:

• depositing marking particles as a substantially continuous layer on said thermoplastic imaging surface layer;
• attracting the marking particles to said imaging element magnetically or both magnetically and electrostatically;
• exposing the imaging clement in an imagewise pattern with near-infrared radiation, whereby said thermoplastic imaging surface layer is heated so that the marking particles addressed by said exposing migrate into said thermoplastic imaging surface layer to form an imagewise pattern and
• removing unaddressed marking particles from said thermoplastic imaging surface layer, wherein both the marking particles and the thermoplastic imaging surface layer comprise:
• an acid photogenerator comprising an aromatic onium salt selected from the group consisting of aryl halonium salts, aryl phosphonium salts, aryl arsenonium salts, aryl sulfonium salts, aryl selenonium salts, aryl diazonium salts, and mixtures thereof and
• a near-infrared radiation-absorbing dye or pigment.

A method of migration imaging using an imaging element with a thermoplastic imaging surface layer comprising:

• an acid photogenerator comprising an aromatic onium salt selected from the group consisting of aryl halonium salts, aryl phosphonium salts, aryl arsenonium salts, aryl sulfonium salts, aryl selenonium salts, aryl diazonium salts, and mixtures thereof, said method comprising:
• depositing marking particles as a substantially continuous layer on said thermoplastic imaging surface layer, wherein the marking particles comprise
• a near-infrared radiation-absorbing dye or pigment;
• attracting the marking particles to said imaging element magnetically;
• or both magnetically and electrostatically;
• exposing the imaging element in an imagewise pattern with near-infrared radiation, whereby said thermoplastic imaging surface layer is heated so that the marking particles addressed by said exposing migrate into said thermoplastic imaging surface layer to form an imagewise pattern;
• and
• removing unaddressed marking particles from said thermoplastic imaging surface layer.

A method of migration imaging using an imaging element with a thermoplastic imaging surface layer, wherein said thermoplastic imaging surface layer comprises:

• a thermoplastic binder selected from the group consisting of polycarbonates, polyesters, polyolefins, phenolic resins, paraffins, polystyrenes, and mixtures thereof,
• an acid photogenerator comprising an aromatic onium salt selected from the group consisting of aryl halonium salts, aryl phosphonium salts, aryl arsenonium salts, aryl sulfonium salts, aryl selenonium salts, aryl diazonium salts, and mixtures thereof;
• and
• a near-infrared radiation-absorbing dye or pigment, said method comprising:
• depositing marking particles as a substantially continuous layer on said thermoplastic imaging surface layer;
• attracting the marking particles to said imaging element magnetically;
• or magnetically and electrostatically;
• exposing said imaging element in an imagewise pattern with near-infrared radiation, whereby said thermoplastic imaging surface layer is heated so that the marking particles addressed by said exposing migrate into said thermoplastic imaging surface layer to form an imagewise pattern;
• and
• removing unaddressed marking particles from said thermoplastic imaging surface layer.