Negative working, heat sensitive lithographic printing plate precursor

1. A heat-sensitive negative-working lithographic printing plate precursor comprising:

a support having a hydrophilic surface or which is provided with a hydrophilic layer, and a coating provided thereon, the coating including an image-recording layer which includes hydrophobic thermoplastic polymer particles, a binder, and an infrared absorbing dye; wherein

the amount of the infrared absorbing dye, without taking into account an optional counter ion, is more than 0.80 mg per m 2 of a total surface of the thermoplastic polymer particles, measured by Hydrodynamic Fractionation;

the amount of hydrophobic thermoplastic polymer particles relative to a total weight of all ingredients of the imaging layer is at least 60%; and

the hydrophobic thermoplastic polymer particles have an average particle diameter, measured by Photon Correlation Spectroscopy, of more than 20 nm and less than 36 nm.

2. The heat-sensitive negative-working lithographic printing plate precursor according to claim 1 , wherein the amount of the infrared absorbing dye, without taking into account an optional counter ion, is more than 1.00 mg per m 2 of the total surface of the thermoplastic polymer particles.

3. A heat-sensitive negative-working lithographic printing plate precursor comprising:

a support having a hydrophilic surface or which is provided with a hydrophilic layer, and a coating provided thereon, the coating including an image-recording layer which includes hydrophobic thermoplastic polymer particles, a binder, and an infrared absorbing dye; wherein

the hydrophobic thermoplastic polymer particles have an average particle diameter, measured by Photon Correlation Spectroscopy, of more than 10 nm and less than 40 nm;

the amount of hydrophobic thermoplastic polymer particles relative to a total weight of all ingredients of the imaging layer is at least 60%; and

the amount of the infrared absorbing dye, without taking into account an optional counter ion, is more than 1.00 mg per m 2 of a total surface of the thermoplastic polymer particles, measured by Hydrodynamic Fractionation.

4. The heat-sensitive negative-working lithographic printing plate precursor according to claim 3 , wherein the amount of the hydrophobic thermoplastic polymer particles relative to the total amount of all ingredients of the image-recording layer is at least 70%.

5. The heat-sensitive negative-working lithographic printing plate precursor according to claim 3 , wherein the amount of the hydrophobic thermoplastic polymer particles relative to the amount of the binder is at least 4:1.

6. The heat-sensitive negative-working lithographic printing plate precursor according to claim 4 , wherein the amount of the hydrophobic thermoplastic polymer particles relative to the amount of the binder is at least 4:1.

7. The heat-sensitive negative-working lithographic printing plate precursor according to claim 3 , wherein the image-recording layer further includes an organic compound including at least one phosphonic acid group or at least one phosphoric acid group, or a salt thereof.

8. The heat-sensitive negative-working lithographic printing plate precursor according to claim 4 , wherein the image-recording layer further includes an organic compound including at least one phosphonic acid group or at least one phosphoric acid group, or a salt thereof.

9. The heat-sensitive negative-working lithographic printing plate precursor according to claim 6 , wherein the image-recording layer further includes an organic compound including at least one phosphonic acid group or at least one phosphoric acid group, or a salt thereof.

10. A heat-sensitive negative-working lithographic printing plate precursor comprising:

a support having a hydrophilic surface or which is provided with a hydrophilic layer, and a coating provided thereon, the coating including an image-recording layer which includes hydrophobic thermoplastic polymer particles, a binder, and an infrared absorbing dye; wherein

the hydrophobic thermoplastic polymer particles have an average particle diameter, measured by Photon Correlation Spectroscopy, of more than 10 nm and less than 40 nm;

the amount of the infrared absorbing dye, without taking into account an optional counter ion, is more than 0.80 mg per m 2 of a total surface of the thermoplastic polymer particles, measured by Hydrodynamic Fractionation;

the amount of hydrophobic thermoplastic polymer particles relative to a total weight of all ingredients of the imaging layer is at least 60%; and

the image-recording layer further includes an organic compound including at least one phosphonic acid group or at least one phosphoric acid group, or a salt thereof.

11. A method for making a lithographic printing plate comprising the steps of:

providing a heat-sensitive negative-working lithographic printing plate precursor including:

a support having a hydrophilic surface or which is provided with a hydrophilic layer, and a coating provided thereon, the coating including an image-recording layer which includes hydrophobic thermoplastic polymer particles, a binder, and an infrared absorbing dye; wherein

the hydrophobic thermoplastic polymer particles have an average particle diameter, measured by Photon Correlation Spectroscopy, of more than 10 nm and less than 40 nm;

the amount of the infrared absorbing dye, without taking into account an optional counter ion, is more than 0.80 mg per m 2 of a total surface of the thermoplastic polymer particles, measured by Hydrodynamic Fractionation; and

the amount of hydrophobic thermoplastic polymer particles relative to a total weight of all ingredients of the imaging layer is at least 60%

exposing the printing plate precursor to heat or infrared light;

mounting the exposed printing plate precursor on a printing press; and

developing the printing plate precursor by supplying ink and/or fountain solution to the printing plate precursor thereby removing unexposed areas of the image recording layer.

12. The method according to claim 11 , wherein the infrared light used to expose the printing plate precursor has an energy density, measured on the surface of the precursor, of 200 mJ/cm 2 or less.

13. The method according to claim 12 , further comprising the steps of:

supplying ink and fountain solution to the printing plate mounted on a printing press; and

transferring the ink to paper.