Abstract: A plurality of physical drives is grouped into a physical drive group. The plurality of physical drives comprises at least a first physical drive and a second physical drive. At least the first physical drive and the second physical drive are striped to create at least a first virtual drive and a second virtual drive. The first virtual drive is comprised of storage space residing on the first physical drive and the second virtual drive is comprised of storage space residing on the second physical drive. Storage data is distributed across at least the first virtual drive and the second virtual drive using at least one redundant array of independent disks (RAID) technique to create at least a first virtual volume and a second virtual volume. When a physical drive fails, data from the failed physical drive may be reconstructed using temporary stripes from a virtual drive.

Abstract: The present invention generally relates to an imaging system, and more specifically, a method and apparatus for accurately predicting toner usage and hence toner dispensing requirements in an imaging system. More, specifically, the present invention relates to a toner concentration control system for maintaining toner concentration in a developer structure, which is connected to a dispenser containing toner.

Abstract: In process control loops by keeping the DMA (Developed Mass per unit Area) under control, the print quality can be satisfactorily maintained to within tolerance in spite of temporal variabilities in subsystem parameters. The DMA is measured by creating patches in the interdocument zones. Three patches are created, one at high area coverage (90% to 100%), one at low area coverage (0 to 20%) and one at mid tone (around 50%). These DMA readings are compared to the setpoints. The errors are processed in the controller to generate the internal process parameters known as the cleaning voltage, discharge ratio and development voltage. These internal parameters have well known meaning to the physical xerographic process. The cleaning voltage is used to indicate the background in printing. The discharge ratio gives an indication of how much dot growth is present in the halftones. Finally, the development voltage is proportional to how much toner is laid on the photoreceptor.