In known electrophotographic art, an electrostatically imaged metal printing plate can be prepared for imaging by preheating to a first temperature, and then heating to a second temperature, without developing an image between the heating steps. An example of this type of method can be found in U.S. Pat. No. 6,675,710, incorporated by reference in its entirety herein. This method is used to obtain an imaged element with adequate toner fusing while avoiding substrate buckling and distortion. Although certain methods are known for preparing an electrostatically imaged metal printing plate, such as the aluminum plate of the '710 patent, there are no corresponding methods for controlling a temperature of extremely heat sensitive substrates (e.g. non-metal substrates such as plastics used for labels) in electrophotographic devices or otherwise.
It is appreciated herein that a temperature of a metal printing plate can be relatively easy to control, unlike a non-metal, heat sensitive substrate. For example, metal has a small specific heat and high conductivity. This means that the temperature of a sheet of metal increases rapidly and relatively uniformly as heat is added, and it is therefore easy to control a fusing temperature at a fuser when using metal as a substrate. Metal substrates are also not extremely heat sensitive at the temperatures used for fusing toner images. However, for non-metallic substrates, the relative inability to heat a non-metal substrate quickly and uniformly can cause error and delay in reaching a fusing temperature at which a toner composition can be fused to the substrate, and allowing all fusing heat to be derived from the fuser can easily cause distortion and other degradation of the non-metal substrate. Further, relying on the fuser for all heat input to reach a fusing temperature can result in excessive heating for certain non-metal substrates, and early failure of the fuser apparatus.
It is now desirable to expand electrophotographic imaging to include a wide variety of substrate materials. Non-metal substrates can include heat sensitive materials. The heat sensitive materials can include heat sensitive films typically formed of flexible materials, including heat-shrink film. Imaged flexible materials can then be used in flexible displays, packaging, bottle labeling, container labeling, and the like. However, because of their flexible, thermosensitive nature, these non-metal substrates can be highly subject to distortion, tearing, buckling, degradation, etc. compared to metallic substrates or normal paper substrates.
In view of the foregoing, it would be advantageous to employ electrostatic imaging of a non-metal substrate in such a manner as to achieve adequate toner fusing and minimize or eliminate undesired buckling, distortion, and degradation of the non-metal substrate during fusing. Because fusing can be the speed-limiting step in an electrophotographic imaging device, an increase in speed at the fusing apparatus can improve an overall speed of the imaging device.
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