Abstract: Density or reflectance targets for respective first and second marking engines of a document processing system are determined. A series of control patches is printed with the respective first and second marking engines. Relative reflectance values of each control patch printed with the first and second engines are determined. First marking engine relative reflectance error values of each control patch and second marking engine relative reflectance error values of each control patch are determined correspondingly based at least on (a) corresponding first engine relative reflectance value and target relative reflectance value and (b) corresponding second engine relative reflectance value and target relative reflectance value. Based at least on one of the first and second marking engine relative reflectance error values, at least one of the first and second engine relative reflectance targets is adjusted.

Abstract: A printer image drum is provided that includes a cylindrical drum formed of a first material, a bearing formed of a second material and an end bell formed of the first material with the end bell mounting the cylindrical drum on the bearing. The image drum is structured so that the bearing is plastically undeformed at a temperature of about 20° C. and so that an outer face of the cylindrical drum retains a consistently cylindrical shape at about 70° C.

Abstract: A non-gated print media crossover for a printing system includes crossover pathways which intersect at a crossover junction. A control system controls arrival of sheets of print media at the crossover junction whereby a sheet conveyed on the first crossover pathway traverses the junction in an intersheet gap between sheets traversing the junction on the second crossover pathway. The printing system includes print media processing units, such as marking engines, paper sources, and output destinations, which are connected by a conveyor system incorporating the crossover.

Abstract: An ink jet printer includes a printer housing, an imaging drum, a drum frame connected to the printer housing and the imaging drum, a print head frame movably mounted in the printer housing, at least two print heads mounted to the print head frame, a first alignment pin connected to the print head frame, and a second alignment pin connected to the print head frame. The imaging drum includes first and second ends. The drum frame includes a first support connected to the first end of the imaging drum and a second support connected to the second end of the imaging drum. The first support includes a first docking station and the second support includes a second docking station. The print head is movable between a printing position and a cleaning position. Each alignment pin connects to the print head frame and extends generally towards the drum frame. The first alignment pin is adapted to be received by the first docking station when the print head frame is moved into the printing position.

Abstract: An image processing apparatus including tandem print engines is provided for forming an image on an image receiving substrata. The apparatus includes a first print engine and a second print engine downstream from the first print engine. The second print engine is slaved to the first print engine. The first print engine has a first photoreceptor and a first period of revolution. The second print engine has a second photoreceptor and a second period of revolution. The image processing apparatus further includes an intermediate inverter that inverts the image receiving substrate between the first print engine and the second print engine. The inverter determines a phase difference between a first seam signal from the first photoreceptor and a second seam signal from the second photoreceptor.

Abstract: A reflex printing device having multiple print heads mounted at different locations around the circumference of the drum at different “angles” and an encoder disk mounted on the drum to allow for detection of the drum position as a function of time. An image defect due to a misalignment in the print process direction of the output from the multiple print heads is corrected by detection of an encoder position error function subtracted from itself shifted by the angle between the print heads.

Abstract: A system and method for delivering phase change ink to a plurality of printheads is provided. The system includes an ink source having a housing for holding solid phase change ink, an ink melter assembly having a heated ink contact portion for melting the solid phase change ink and a drip point. The system also includes a first conduit for transferring the melted ink to a first printhead, and a second conduit for transferring the melted ink to a second printhead. The method includes melting a solid phase change into the liquid phase, transferring the liquid phase change ink to the first printhead in a first conduit, transferring liquid phase change ink to the second printhead in a second conduit. The solid phase change ink can be stored in a single ink source.

Abstract: A method of maintaining a rotational velocity of an imaging drum during engagement with a transfer roll in an image producing device including: forming a nip to transfer an image from the imaging drum to media when the imaging drum is in engagement with the transfer roll; maintaining a substantially constant imaging drum rotational velocity mode during engagement with the transfer roll; sensing a lead edge of portion of the media prior to entering the nip; augmenting torque assist to increase the torque of the transfer roll when the media is in the nip for a defined period; and resuming the substantially constant imaging drum rotational velocity mode while a second portion of the media is in the nip.

Abstract: Convenient placement of media supply trays in a printing apparatus is provided by placing the media supply trays in the printer enclosure at an elevation above the elevation of the print engine. In particular, the imaging station of the print engine is placed at a lower elevation within the printer enclosure than are the media feed heads for each media supply tray. In addition, a substrate heater is positioned along the media path between the media feed heads and the imaging station when the print engine is a phase change ink jet printhead.