Abstract: The present application is directed to methods of controlling the transfer voltage in a transfer nip formed between the photoconductive member and the transfer member. The methods offset the effects of large transfer current spikes caused when a media sheet enters and exits the transfer nip and account for temperature and humidity operating parameters using wet-bulb temperature measurements to adjust the transfer voltage. The control may include either ramping up or ramping down the transfer voltage. The ramped transfer voltage may include a series of alternating positive and negative steps that generally trend to ramp up or down. The size of the steps may further be adjusted to provide a smooth transition.

Abstract: A system for adjusting a selected operating parameter of an image forming device to control white vector based on selected environmental conditions includes an image forming station having a photoconductive surface with a latent image formed by discharged areas leaving non-discharged areas different from the discharged areas, a sensor mechanism for measuring selected environmental conditions of dry-bulb temperature and relative humidity, a control mechanism for reading the sensor mechanism to adjust the voltage bias of a charging unit by an offset applied to the charging unit based on a wet-bulb temperature value so as to minimize white vector without enabling onset of development of toner background on non-discharged areas, and a memory connected to and accessible by the control mechanism and storing a lookup table of a list of wet-bulb temperature values related to measured dry-bulb temperature and relative humidity values and correlated to a list of voltage bias offsets.

Abstract: A capacitive sensor to detect toner volume levels in a toner container within an image forming device includes opposed electrodes disposed within the interior of the toner container. The opposed electrodes form a capacitor characterized by an inherent capacitance that varies in response to an amount of toner that exists between the opposed electrodes. A corresponding sensor circuit is electrically coupled to the opposed electrodes and adapted to sense an instantaneous capacitance of the capacitor to determine the amount of toner that exists between the opposed electrodes. The opposed electrodes may have different shapes and configurations, including for example, plates disposed within the toner container or the interior walls of the container itself. The sensor circuit is configured to apply an alternating current signal to the opposed electrodes and sense an output voltage that is indicative of an instantaneous capacitance of the capacitor corresponding to toner volume within the container.

Abstract: The present application is directed to methods and devices for compensating for transfer belt charge buildup in an image forming device. In one embodiment, the method includes determining the charge buildup on the transfer belt due to an applied transfer voltage. A first image of a multi-image print job is printed using a first transfer voltage. The transfer voltage may then be adjusted for printing one or more subsequent images of the multi-image print job.

Abstract: A toner image transfer apparatus in a printer is provided. The toner image transfer apparatus comprises a transfer belt structure, a rotatable transfer rod and a transfer roll retraction mechanism. The transfer belt structure comprises a driven toner image transfer belt and a rotatable backup roll engaging an Inner surface of the transfer belt. The rotatable transfer roll is adapted to define a nip with the belt and backup roll. The transfer roll refraction mechanism comprises motion transfer structure coupled to the transfer roll and drive apparatus associated with the motion transfer structure.

Abstract: A capacitive sensor to detect toner volume levels in a toner container within an image forming device includes opposed electrodes disposed within the interior of the toner container. The opposed electrodes form a capacitor characterized by an inherent capacitance that varies in response to an amount of toner that exists between the opposed electrodes. A corresponding sensor circuit is electrically coupled to the opposed electrodes and adapted to sense an instantaneous capacitance of the capacitor to determine the amount of toner that exists between the opposed electrodes. The opposed electrodes may have different shapes and configurations, including for example, plates disposed within the toner container or the interior walls of the container itself. The sensor circuit is configured to apply an alternating current signal to the opposed electrodes and sense an output voltage that is indicative of an instantaneous capacitance of the capacitor corresponding to toner volume within the container.

Abstract: A door assembly movably positioned to a body of an image forming device. The door assembly includes a first frame and a second frame. The first frame is movably attached to the body, and the second frame is movably attached to the first frame. The movable connections between the frames and the main body cause accurate locating of a photoconductive member mounted on the door assembly within the body. In one embodiment, a contour surface within the body contacts the second frame to locate the second frame within the body. Methods of moving the door assembly are also disclosed including moving the door assembly from an open orientation that is spaced from the body, to a closed orientation that is in proximity to the body. The movement of the door assembly causes interaction between the frames and the body to accurately locate the second frame.

Abstract: A method and device for moving media sheets along a media path. In one embodiment, the media path comprises a metering nip, at least one transfer nip downstream from the metering nip, and a feed nip upstream from the metering nip. The feed nip moves the media sheet initially at a faster speed than the metering nip. This speed variation causes a buckle to form in the media sheet that aligns the leading edge. The media sheet is then moved from the metering nip into the transfer nip. The metering nip may move the media sheet at a faster speed than the transfer nip again forming a buckle in the media sheet. As the media sheet is moved through the transfer nip, it is tacked to a transfer belt such that it moves consistently through the remaining downstream transfer nips.

Abstract: An electrophotographic image forming apparatus comprises a drive roller having a textured finish with a plurality of microscopic protrusions and a plurality of microscopic depressions; the drive roller comprising a shaft and a surface coating on the shaft; a flexible belt having a first hardness driven by the drive roller, the belt moving at least one of a toner image or a recording media having a toner image thereon; with the surface coating comprising a base compound and plurality of grit particles having a second hardness which is higher than the first hardness. The grit coating may advantageously have a thickness of not more than about 50 microns. The grit particles may comprise one or more ceramics, or one or more polymer compounds, or other materials. The drive roller advantageously has a coefficient of static friction of at least 0.5 with the belt.

Abstract: Each sheet is picked from a stack of sheets with the time of it being picked being determined in accordance with the time of the prior pick. The sum of the times to advance a sheet its length and a desired gap between adjacent sheets is equal to a pick delay time and an expected feed time. If the measured feed time of the prior sheet exceeds a maximum feed time, the pick delay is the same as for the prior sheet. If the measured feed time of the prior sheet does not exceed the maximum feed time and the measured feed time of the prior sheet was less than the expected feed time, the pick delay is greater than the pick delay of the prior sheet. If the measured feed time of the prior sheet does not exceed the maximum feed time and the measured feed time of the prior sheet was not less than the expected feed time, the pick delay is less than the pick delay for the prior sheet.

Abstract: An image forming apparatus includes a print media supply with a pair of opposite sides and a bottom for supporting a plurality of print media sheets. A paper feed assembly defines a media path through which the print media sheets travel. A sheet picker assembly includes a sheet picker positioned adjacent to one of the sides of the print media supply. The sheet picker is configured to move a picked sheet in a pick direction substantially parallel to the bottom from the print media supply into the print media path. A separator dam is positioned between the print media supply and the paper feed assembly. The separator dam includes a wall positioned at a transverse angle relative to the bottom. The separator dam includes at least one resistive strip or abutments on the wall. The resistive strip or abutment is positioned adjacent the side which is opposite the one side. The resistive strip or abutment has a resistance to paper movement which is greater than the first coefficient of friction.

Abstract: Bracket (1) containing a gear train holds the end of spring (19) wound in a direction to be opened when the bracket moves up from the paper tray (7). Spring (19) is wound on an arbor (15) which is mounted on a shaft (9) which is located on the pivot axis of the bracket. Spring (17) is wound on a second part of the arbor in a direction to be closed when the bracket moves away from the tray. Spring (19) has a much tighter grip on the arbor than spring (17). In operation the bracket resists upward movement under the influence of stiff paper being fed, and is slowed in its downward movement to reduce bounce, which increases the speed at which a second sheet can be fed.