Apparatus and method for deposting an overcoat on an image on a substrate

A method of overcoating a dry and fixed printed image on a printer substrate in the form of an individual sheet or a roll previously printed upon with a laser jet or a xerographic printer, the method comprising:

• applying a source of electromagnetic radiation to the printer substrate including the dry and fixed printed image and, with a temperature sensor, measuring temperature rises rate of a portion of the dry and fixed printed image and a portion of the printer substrate not including the dry and fixed printed image;
• based on the measured temperature rise rates, calculating an expected time period over which the portion of the dry and fixed printed image and the portion of the printer substrate not including the dry and fixed printed image can be exposed to the source of electromagnetic radiation to cause the portion of the dry and fixed printed image to be heated to a temperature within a predetermined temperature range, without also causing the portion of the printer substrate not including the dry and fixed printed image to be heated to within the predetermined temperature range;
• transmitting electromagnetic radiation within a predefined wavelength range to the portion of the dry and fixed printed image on the printer substrate image and the portion of the printer substrate not including the dry and fixed printed image with a radiative source for a period of time based on the calculated expected time period, such that the electromagnetic radiation is absorbed by the portion of the dry and fixed printed image to heat the portion of the dry and fixed printed image to the predetermined temperature range as measured by the temperature sensor;
• depositing an overcoating powder onto the heated portion of the dry and fixed printed image with a depositing device, the overcoating powder having a melting point within the predetermined temperature range such that upon deposition thereof, the overcoating powder adheres and/or melts onto the heated portion of the dry and fixed printed image;
• and,
• removing any residual overcoating powder not adhered to the heated portion of the dry and fixed printed image or the portion of the printer substrate not including the dry and fixed printed image with a residual powder removing device.