Gloss Control Technology
Recent years have seen a growing need for on-demand publishing devices capable of faithful color reproduction and high image quality.
Fuji Xerox has been developing various technologies that enable high image quality, including a technology to reduce gloss non-uniformity within a page by focusing on the fact that gloss non-uniformity occurring at the fusing unit leads to color non-uniformity within a page.
The gloss level varies depending on the level of flatness of the paper's fused toner image surface. A high level of such surface flatness also results in high glossiness. The level of flatness that affects gloss largely depends on the amount of heat received by the toner during the fusing process, and the lower heat roll temperature that results when heat is dissipated by paper passing through the roll is a significant cause of gloss non-uniformity.
To resolve gloss non-uniformity within a page, the following measures were implemented.
- Heat roll material with an elastic layer having high thermal conductivity (to prevent lowering of the heat roll temperature)
- External heating roll to heat the heat roll (to prevent lowering of the heat roll temperature)
- Multi-step adjustment of heat roll speed when paper passes through the heat roll (to increase the dwell time to compensate for lower heat roll temperature)
By implementing the above, gloss non-uniformity at the trailing edge of paper that resulted from lower heat roll temperature was successfully reduced.
Fig. 1: Structure of the fusing unit
Fig. 2: Surface temperature of the heat roll
As a result of being able to reduce gloss non-uniformity between the leading and trailing edges of a sheet of paper, not only was image quality improved due to reduced non-uniformity within a page, but the gloss levels could also be clearly distinguished by adjusting the fusing conditions. This has allowed adjustment of the gloss level at three levels for coated paper by changing the fusing temperature and speed settings.
Fig. 3: Gloss level adjustment