A ray applying device as a fixer applies ultraviolet or near ultraviolet rays to a recording surface of a thermosensitive recording sheet. The recording surface is extended two-dimensionally in main and sub scan directions. A plasma display panel extends in the main scan direction, for emitting the ultraviolet or near ultraviolet rays.

A yellow luminous-element array, which is an optical fixing unit, includes a large number of yellow LEDs emitting ultraviolet rays. The LEDs in each of lines extending in a feeding direction are connected in series. Integral illuminance of each line is adjusted by changing electrical energy to be supplied to the respective lines. The integral illuminance of each line extending in the feeding direction is measured to obtain illuminance distribution relative to a scanning direction when the yellow luminous-element array is examined at the time of manufacture thereof. The integral illuminance of each line is corrected so as to even the illuminance distribution.

A print head has an array of surface-emitting light-emitting diodes formed in a chip, near one edge of the chip. The chip is mounted on a conductive pattern on the component surface of a printed circuit board. The printed circuit board includes a material, exposed on the component surface throughout a region adjacent to the above-mentioned edge of the chip, that is less optically reflective than the conductive pattern. Emitted light that leaks through the chip edge is partly or completely absorbed by the exposed material, instead of being reflected by the conductive pattern. The exposed material may be a dielectric coating, a dielectric substrate, or a conductive paste that also bonds the chip to the conductive pattern.

A printing system capable of writing RFID data consistent with print information printed on a print-information recoding medium into an RFID chip carried on the print-information recording medium. The printing system includes a printer engine for printing print information, including at least either one of contactlessly readable information and image information visible to human being, onto at least the print-information recording medium, and an RFID reader/writer for writing RFID data consistent with the print information into the RFID chip carried on the print-information recording medium.

A UV curing apparatus and method is provided for enhancing UV curing of inks, coatings and adhesives having UV photo initiators therein by subjecting the UV curable inks, coatings or adhesives to UV light at different wavelengths. Preferably, the UV LED assemblies are alternated in rows and emit light at a wavelength between 180 nm and 420 nm. A row of UV-LED assemblies which emit light in the visible spectrum can be included so a user can visually see if the apparatus is working. A cooling system can be provided for maintaining the UV-LED assemblies at a desired temperature to maintain light intensity and the UV LED assemblies are placed at a distance from the UV curable product which will provide a uniform pattern of light diverging from the UV-LED chips of at least 50% the power output of the UV-LED chips at a viewing cone angle of 2.theta..sub.1/2. Still further the apparatus can be combined with an ink, coating or adhesive having photo initiators that are activated by light at more than one wavelength.