Method and apparatus for variable gloss reduction
Various variable gloss reduction techniques are disclosed. In one embodiment, a gloss reduction technique is disclosed using a textured roller and a wiper impregnated with fuser oil to create a differential gloss pattern that reduces the gloss of an image printed on a substrate. In one embodiment, a gloss reduction technique is disclosed using a combination of heat and pressure to create a differential gloss pattern that reduces the gloss in specific regions of an image printed on a substrate. In one embodiment, a gloss reduction technique is disclosed using a differential gloss pattern to generate a security mark on a printed image to prevent against copying or fraudulent misrepresentation of the image.
1. An apparatus for providing variable gloss adjustment, comprising:
a textured roller configured to imprint a high frequency texture onto a smooth toner layer applied on a substrate, the high frequency texture being imprinted by an application of a selected combination of heat and pressure by the textured roller onto the smooth toner layer, such that a specular gloss of the smooth toner layer on the substrate is controlled;
a wiper that is composed of a heat resistant felt fabric, which is impregnated with fuser oil and positioned to both clean the textured roller and to apply a coating of the fuser oil directly to the textured roller to form a barrier between the smooth toner layer and the textured roller, such that an adhesion of the smooth toner layer to the textured roller is prevented,
wherein the fabric is of a type that retains the fuser oil and applies the oil continuously to the textured roller on each revolution of the textured roller; and
a controller configured to control a series of gas nozzles spaced along the textured roller, each gas nozzle having a valve to control an amount of gas that can escape from the nozzle,
and the controller configured to control the gas nozzles to apply cooling in sequential scan lines to develop a raster image of temperature difference on the textured roller as the textured roller rotates to create a gloss difference on the smooth toner layer formed on the substrate.
2. The apparatus of claim 1 , wherein one of the heat and the pressure is adjustable so as to adjust the specular gloss of the smooth toner layer.
3. The apparatus of claim 1 , further comprising:
a toner applicator configured to apply the smooth toner layer on the substrate prior to the smooth toner layer being imprinted with the high frequency texture.
4. The apparatus of claim 1 , further comprising:
one or more sensors coupled to the textured roller, the one or more sensors configured to control the selected combination of heat and pressure for adjusting the specular gloss of the smooth toner layer.
5. The apparatus of claim 4 , wherein the one or more sensors comprise infrared, non-contact temperature sensors that form a closed loop control system for controlling a temperature of the textured roller to adjust the heat for adjusting the specular gloss.
6. The apparatus of claim 5 , wherein the infrared, non-contact temperature sensors are configured to measure a current temperature of the textured roller and to cause an adjustment of power to be applied to an induction heater to maintain the temperature of the textured roller at a desired set point.