Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by developer roll. The developer roll adds toner to the drum to develop a latent image on the drum for transfer to media or an intermediate transfer member at a transfer roll. One or more high voltage power supplies communicate with a controller to set voltages on the rolls. During times of non-imaging, but rotation of the drum, the charge roll charges the drum to less than a Paschen breakdown voltage of the drum. A voltage of the transfer roll is determined that corresponds to a temperature and relative humidity of an operating environment of the imaging device and the developer roll is charged based thereon. The charge of the transfer roll is set close to the charge of the drum, but higher in magnitude. A laser may also discharge the drum.

Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by developer roll. The developer roll adds toner to the drum to develop a latent image on the drum for transfer to media. One or more high voltage power supplies communicate with a controller to set voltages on the rolls. The controller determines whether imaging of the media is to occur at a time when the drum is rotating. If not, a laser beam discharges the drum and the voltage on the charge roll is decreased to reduce the charge on the drum, but the controller maintains the voltage differential between the drum and the developer roll.

Abstract: An imaging device has first image transfer from photoconductive drums to an intermediate transfer member (ITM) and second image transfer from the ITM to media. Transfer rolls oppose the drums from an opposite side of the ITM and electrically ground to a frame of the imaging device by mechanical connection. The rolls may be laterally offset from the drums. The ITM has relatively low surface and volume resistivity. An imaging subassembly may include the frame, the ITM, and the transfer rolls grounded to the frame.

Abstract: An imaging device has first image transfer from photoconductive drums to an intermediate transfer member (ITM) and second image transfer from the ITM to media. Transfer rolls oppose the drums from an opposite side of the ITM and electrically ground to a frame of the imaging device by mechanical connection. The rolls may be laterally offset from the drums. The ITM has relatively low surface and volume resistivity. An imaging subassembly may include the frame, the ITM, and the transfer rolls grounded to the frame.

Abstract: An imaging device has first image transfer from photoconductive drums to an intermediate transfer member (ITM) and second image transfer from the ITM to media. Transfer rolls oppose the drums from an opposite side of the ITM and electrically ground to a frame of the imaging device by mechanical connection. The rolls may be laterally offset from the drums. The ITM has relatively low surface and volume resistivity. An imaging subassembly may include the frame, the ITM, and the transfer rolls grounded to the frame.

Abstract: A shield may be provided over a printer developer roll, adjacent to a doctor blade, to reduce toner dusting and toner accumulations. The shield may slightly conform to the curvature of the developer roll in some embodiments. As a result, toner accumulations on surfaces which the customer must touch may be reduced.

Abstract: A shield may be provided over a printer developer roll, adjacent to a doctor blade, to reduce toner dusting and toner accumulations. The shield may slightly conform to the curvature of the developer roll in some embodiments. As a result, toner accumulations on surface which the customer must touch may be reduced.

Abstract: Rubber charge roller cores are coated with loose particulate silicon carbide. Excess powder is removed, and the rollers are used in normal operation without an additional outer layer. Consistent, long-life operation of the charge roller is realized.

Abstract: An improved electrophotographic printer is provided in which the voltage applied to the charge roller is automatically adjusted to compensate for its changing characteristics over its life span. A high voltage DC power supply includes an output that is connected to the charge roller, and the input side of this high voltage DC power supply is controlled by a microprocessor of the print engine. The print engine controls the output voltage of the high voltage DC power supply by changing the duty cycle of the pulse-width modulated control signal that is supplied to the input of the high voltage DC power supply. A look-up table contains the correct duty cycle for the pulse-width modulated control signal with respect to the number of prints that have been made. The result of the inspection of the look-up table is used by the microprocessor of the print engine to control the correct duty cycle for the pulse-width modulated signal.