In the Pro C5200S/C5210S, DEMS (Development Electric-field Modulation System) reduces banding and color unevenness which result from the change of distance between the drum and the development roller.
Small eccentricities in the rotation of the drum, charge roller, and development roller cause variations in charge on the drum, and this causes uneven image density. To correct for this, the machine monitors the image density as the drum, charge roller, and development roller rotate. To do this, the machine makes a pattern, while monitoring the angle of rotation of the drum and development roller (using the drum home position sensor and development roller home position sensor). The ID sensor above the ITB monitors variations in density of the pattern. Then, during image creation, development bias and charge voltage are adjusted for different phases of drum and development roller rotation, based on the ID sensor. The amount of toner is adjusted and color unevenness is reduced. Because this works for periodical eccentricities of both the drum and the development roller, it reduces banding at 190-mm intervals (drum) and banding at 53-mm intervals (development roller).
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A | Arithmetic Processing
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