The Influence of Flash Fusing Variables on Image Fixing Quality

摘要

Fusing or fixing is the final stage in electrophotographic printing process. Flash fusing, as a non-contact method has not been implemented alone in commercial scale, it is usually used with black and white prints as a post fusing method, to remove the gloss and improve the fixing quality. This study focuses on the mechanism of Near-Infra-Red (NIR) flash fusing. At the outset, the hypothesis was that the method would be very efficient due to lack of absorption of NIR radiation by paper. Experiments were carried out in separate flash fusing unit, which was built to be operated by controllable flashing energy, pulse width and damping parameter. The influences of flashing energy levels on irregular and spherical shape toners with different thermal properties were determined. Unfused images of different grey scale were transferred by electrostatic means to different paper grades by commercial laser printer. Image adhesion was evaluated by a modified controllable tape test. The results show that the spherical toner was better than the irregular toners due to the even property distributions arising from the even shape. Therefore, the fusing quality in terms of image enhancement and image adhesion is higher. Initially, flashing energy is consumed by the toner particles to cohere to each other, and the rest of the energy -if any remains- for melting and penetrating into the paper. Hence, the pulse width needs to be long enough for an effective fixing process.