Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by a transfer roll to transfer an image from the drum. The drum becomes biased to a negative voltage by setting charges of negative voltage on both the charge roll and transfer roll. A controller switches the bias of the transfer roll to a positive voltage from the negative voltage and a delta or difference in a charge of the drum is determined from before and after the switching. Based on the delta, the voltage on the charge roll is boosted by a boost voltage to improve the charge on the drum. In this way, deteriorating or defective charge rolls can be still used to charge the drum to a proper voltage for imaging. Techniques for determining the delta, the boost and the magnitude of voltage charges are further embodiments.

Abstract: An imaging device includes a photoconductive drum charged by a charge roll and opposed by a transfer roll to transfer an image from the drum. The drum becomes biased to a negative voltage by setting charges of negative voltage on both the charge roll and transfer roll. A controller switches the bias of the transfer roll to a positive voltage from the negative voltage and a delta or difference in a charge of the drum is determined from before and after the switching. Based on the delta, the voltage on the charge roll is boosted by a boost voltage to improve the charge on the drum. In this way, deteriorating or defective charge rolls can be still used to charge the drum to a proper voltage for imaging. Techniques for determining the delta, the boost and the magnitude of voltage charges are further embodiments.

Abstract: An electrophotographic imaging device having a method of printing which includes determining whether a duty cycle state in the imaging device has changed; selecting one of a full toner density calibration and a partial toner density calibration based on the determining; performing the one of the full toner density calibration and the partial toner density calibration; identifying a toner density to be applied during printing as a result of the performing; developing a toned image having a toner density equal to the toner density identified; and printing the toned image on a media sheet, wherein the full toner density calibration is skipped upon at least a determination that the duty cycle state has remained the same.

Abstract: An electrophotographic imaging device having a method of printing which includes determining whether a duty cycle state in the imaging device has changed; selecting one of a full toner density calibration and a partial toner density calibration based on the determining; performing the one of the full toner density calibration and the partial toner density calibration; identifying a toner density to be applied during printing as a result of the performing; developing a toned image having a toner density equal to the toner density identified; and printing the toned image on a media sheet, wherein the full toner density calibration is skipped upon at least a determination that the duty cycle state has remained the same.

Abstract: An imaging device has a photoconductive drum with a surface that is selectively discharged to create a latent electrostatic image for attracting toner for transfer to a media moving in a process direction. The image is divided into multiple segments along the process direction and discharged pixels per segment are counted. An accumulator keeps track of the numbers of pixels per revolutions of a roller that applies the toner to the drum. Upon meeting a predetermined deficiency in the counts of pixels in any given segment, an artificial image gets generated on the surface of the photoconductive drum that supplies the missing pixels, per segment. The image gets developed with toner, but does not transfer to the media. Lubrication occurs on the surface of the drum and each segment retains a relatively common number of imaging pixels that get developed over time.

Abstract: An imaging device has a photoconductive drum with a surface that is selectively discharged to create a latent electrostatic image for attracting toner for transfer to a media moving in a process direction. The image is divided into multiple segments along the process direction and discharged pixels per segment are counted. An accumulator keeps track of the numbers of pixels per revolutions of a roller that applies the toner to the drum. Upon meeting a predetermined deficiency in the counts of pixels in any given segment, an artificial image gets generated on the surface of the photoconductive drum that supplies the missing pixels, per segment. The image gets developed with toner, but does not transfer to the media. Lubrication occurs on the surface of the drum and each segment retains a relatively common number of imaging pixels that get developed over time.

Abstract: A developer unit according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. A magnetic roll is mounted on the housing. An outer surface of a sleeve of the magnetic roll is positioned to carry the developer mix from the reservoir through a front portion of the magnetic roll that is exposed from the reservoir to permit transfer of toner from the outer surface of the sleeve to a photoconductive drum and back to the reservoir as the sleeve rotates in an operative rotational direction. An air vent is positioned along a rear portion of the magnetic roll for exiting air in the reservoir from the housing. An entire opening of the air vent is positioned vertically higher than the rotational axis of the sleeve when the developer unit is in an operative orientation.

Abstract: A developer unit for a dual component development electrophotographic image forming device includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An axial sealing rib projects from an inner side of the housing toward the outer surface of a sleeve of a magnetic roll. The axial sealing rib extends along an axial length of the sleeve. A distal end of the axial sealing rib is positioned in close proximity to and spaced from the outer surface of the sleeve. The axial sealing rib is positioned to impede the flow of developer mix in the reservoir in a direction counter to an operative rotational direction of the sleeve.

Abstract: A developer unit for a dual component development electrophotographic image forming device according to one example embodiment includes a housing having a reservoir for storing a developer mix that includes toner and magnetic carrier beads. An auger is positioned to convey developer mix in the reservoir toward the outer surface of a magnetic roll on a front of the housing. A ledge on an inner surface of the housing extends axially with respect to the magnetic roll along a front of the reservoir. The ledge is positioned upstream from a trim bar and downstream from a pickup pole of the magnetic roll with respect to the operative rotational direction of the magnetic roll. The ledge has a concave curved inner surface that is open to the reservoir and extends from near the trim bar to near a front side of the auger.