Laser-based thermal printer
One embodiment described pertains to a thermal printer is provided having a spatial light modulator (SLM) to modulate light from a laser source to record information on a thermal-sensitive surface of a recording medium, and a heater adjacent to the medium to preheat the thermal-sensitive surface prior to recording of information thereon. The printer may further include illumination optics for focusing the light beam onto the SLM, and imaging optics to image the light on the thermal-sensitive surface. The heater may comprise a resistive, a convective or a radiant heater. The printer may further include a feed mechanism with a roller having an outer surface in contact with the recording medium for feeding it past the imaging optics, and the heater may be disposed inside of the roller to heat the recording medium in contact with the roller. The heater may be arranged to heat the entire outer surface of the roller, or only a portion thereof. Other embodiments are also described.
1. A thermal printer comprising:
a laser source to generate a light beam;
an imaging system adapted to image the light beam on a thermal-sensitive surface of a portion of a recording medium to record information thereon, the imaging system including a spatial light modulator to modulate light from the laser source; and
a heater adjacent to the recording medium to preheat the thermal-sensitive surface prior to recording of information thereon, the heater adapted to preheat the thermal-sensitive surface to a temperature below a predetermined temperature required to record information on the thermal-sensitive surface,
wherein the spatial light modulator comprises a linear array of diffractive MEMS elements, and wherein each the diffractive MEMS elements comprises a plurality of deformable ribbons having a light reflective planar surface.
2. The thermal printer according to claim 1 , further comprising a feed mechanism including a roller having an outer surface in contact with the recording medium for feeding the recording medium past the imaging system, and wherein the heater is disposed inside of the roller to heat the recording medium in contact therewith through the outer surface thereof.
3. The thermal printer according to claim 2 , wherein the heater is positioned and oriented to heat only a portion of the outer surface of the roller that is in contact with the portion of the recording medium on which information is to be recorded.
4. The thermal printer according to claim 2 , wherein the heater is positioned and oriented to heat substantially the entire outer surface of the roller.
5. The thermal printer according to claim 4 , further comprising:
a temperature sensor; and
a controller to control the heater to maintain the outer surface of the roller at a substantially constant temperature.
6. The thermal printer according to claim 1 , wherein the heater is selected from the group consisting of:
resistive heating elements;
convection heaters; and
radiant heaters.
7. The thermal printer according to claim 1 , wherein the heater comprises a radiant heater positioned and oriented to direct thermal radiation directly on the thermal-sensitive surface of the recording medium.
8. The thermal printer according to claim 1 , wherein the thermal-sensitive surface is preheated to a temperature within a range from 40 degrees Celsius to 70 degrees Celsius.
9. A thermal printing system comprising
a laser source to generate a light beam;
a spatial light modulator assembly to modulate light from the laser source according to electric fields applied to control reflective components within the assembly;
illumination optics configured to focus the light beam onto the spatial light modulator assembly; and
imaging optics disposed in a light path between the spatial light modulator assembly and a thermal-sensitive surface of a recording medium to image the light beam on a portion of the thermal-sensitive surface to record information thereon,
wherein the spatial light modulator assembly comprises a linear array of diffractive MEMS elements, and wherein each the diffractive MEMS elements comprises a plurality of deformable ribbons having a light reflective planar surface.
10. The thermal printing system according to claim 9 , further comprising a heater adjacent to the recording medium to preheat the thermal-sensitive surface prior to recording of information thereon, the heater adapted to preheat the thermal-sensitive surface to a temperature below a predetermined temperature required to record information on the thermal-sensitive surface.
11. A method of thermally recording information on a thermo-sensitive surface of a recording medium, the method including steps of:
pre-heating the thermo-sensitive surface of the recording medium;
generating a light beam from a laser source;
focusing the light beam onto a spatial light modulator assembly;
modulating the light beam reflected from the spatial light modulator assembly in accordance with an electric field applied thereto; and
projecting the light beam reflected from the spatial light modulator onto a portion of the thermal-sensitive surface to record information thereon,
wherein the spatial light modulator assembly comprises a linear array of diffractive MEMS elements, and wherein each the diffractive MEMS elements comprises a plurality of deformable ribbons having a light reflective planar surface.
12. The method according to claim 11 , wherein the thermo-sensitive surface of the recording medium is preheated to a temperature below a predetermined temperature required to record information on the thermal-sensitive surface.