Abstract: An exemplary apparatus herein includes a registration item positioned at the end of a shelf. Further, tamper elements contact the sides of sheets of media on the shelf to align them and push them toward the registration item. In addition, a frame element is connected to each of the tamper elements and a biased member is connected to the frame element. A motor is connected to the biased member. Rotation of the motor moves the tamper elements in a closed curve path motion relative to the shelf and the registration item. With increasing speed of the rotation of the motor, the biased member expands, and this increases the distance of the closed curve path motion and increases the force applied by the tamper elements against the sheets of media being moved toward the registration item along the shelf.

Abstract: A printer detects inoperative inkjets during printing of three dimensional objects. The printer includes an electrically conductive substrate onto which a printhead ejects building material in a test pattern. A plurality of electrically conductive members arranged in a pattern corresponding to the test pattern are moved a predetermined distance towards the substrate so ends of the members either contact the surface of the substrate or the building material on the substrate. An electrical current source coupled to the substrate produces a current in those members contacting the substrate. Thus, the inkjets corresponding to the members in which an electrical current is produced are identified as inoperative and the printing of an object can be suspended to take remedial action with regard to the printhead.

Abstract: A printer detects inoperative inkjets during printing of three dimensional objects. The printer includes a substrate onto which a printhead ejects building and support material in a test pattern. An ultrasonic sensor scans the substrate on the unprinted side and measures thicknesses at a plurality of locations on the substrate. The thickness measurements are used to identify inoperative inkjets in the printhead and the printing of an object can be suspended to take remedial action with regard to the printhead before formation of the object is completed.

Abstract: A sheet-receiving surface comprises retractable bars movable between a first position and a second position. The first position is a first distance away from a mounting support. The second position is a second distance away from the mounting support. The first distance is greater than the second distance. Pivot arms, having a first end and a second end opposite the first end, are rotationally attached at the first end to the retractable bars and rotationally attached at the second end to the mounting support. Bias elements, operatively connected to the pivot arms, bias the retractable bars to the first position. A link is operatively connected to the retractable bars and an actuator. The sheet-receiving surface accumulates sheets of media into sets of sheets. Responsive to operation of the actuator, the link applies a force to move the retractable bars to the second position, forming an opening to allow the sets of sheets to drop, forming a stack of sets of sheets.

Abstract: Sheet stacking apparatus examples herein include a clamp receiving at least two sheets (e.g., a set of sheets). The clamp aligns and holds the set of sheets. The sheet stacking apparatus also includes an ejector device, an elevator platform, and a registration wall. The ejector device moves the set of sheets held by the clamp in a first direction to move the set of sheets to the elevator platform. The ejector device moves the set of sheets held by the clamp in a second direction to move the set of sheets to contact either the elevator platform or a previously stacked set of sheets. The ejector device moves the set of sheets held by the clamp in a third direction, opposite the first direction, to position the set of sheets against the registration wall. The clamp then releases the set of sheets so that they remain against the registration wall.

Abstract: An apparatus includes a compiler surface that receives sheets of media, and a registration surface positioned at one end of the compiler surface. The leading edges of the sheets of media contact and are aligned by the registration surface. A rotatable cam is positioned at the other end of the compiler surface. The rotatable cam has a lobe, and the surface of the lobe is a high-friction surface. When the rotatable cam is at a “first” rotation position, this causes the lobe to contact the bottom sheet as the sheets of media are received onto the compiler surface. When the rotatable cam is at a “second” rotation position, this causes the lobe to move out of the way and avoid contacting any of the sheets of media as the sheets of media are ejected from the compiler surface.

Abstract: A media stack sheet media stack fluffer jet flow is provided to a first plurality of media stack sheets in a media stack. The media stack sheet media stack fluffer jet flow then is provided to a second plurality of media stack sheets in the media stack. The second plurality of media stack sheets are positioned either above or below the first plurality of media stack sheets. Also, a sequence of momentary jet flows form a media stack sheet fluffer jet flow, which is then provided to a plurality of media stack sheets in a media stack.

Abstract: A media stack sheet media stack fluffer jet flow is provided to a first plurality of media stack sheets in a media stack. The media stack sheet media stack fluffer jet flow then is provided to a second plurality of media stack sheets in the media stack. The second plurality of media stack sheets are positioned either above or below the first plurality of media stack sheets. Also, a sequence of momentary jet flows form a media stack sheet fluffer jet flow, which is then provided to a plurality of media stack sheets in a media stack.

Abstract: A sheet separating and feeding system for separating a top sheet from a stack of sheets for sheet feeding, wherein a vacuum feed head has a two dimensional array of multiple vacuum tubes for vacuum engaging the top sheet, and a control system whereby at least a portion of the multiple vacuum tubes are variably positionally controlled relative to the top sheet to engage the top sheet at different levels in a different plane than the external surfaces of the other vacuum tubes so as to provide a variable three dimensional sheet corrugation inducing surface with the multiple vacuum tubes that is variable for different sheet properties.

Abstract: A sheet feeder assembly for acquiring and conveying a sheet comprises a plenum connectable to a vacuum source and having an opening facing the sheet to be conveyed, and a slide plate covering the opening. The slide plate has an acquisition surface facing the sheet to be conveyed and defining apertures in communication with the plenum. A drive mechanism is connected to the slide plate and supported within the plenum, and is operable to translate the slide plate relative to the plenum to convey the acquired sheet while maintaining the vacuum through the apertures. The drive mechanism includes a motor and eccentrically driven link connected to a carriage supporting the slide plate. The motor is coupled to a cam element that drives a flapper valve disposed between the plenum and a vacuum duct. The cam element also drives a height sensing arm supported to contact the top of the stack.

Abstract: A sheet feeding apparatus for feeding a stack of sheets in a direction of movement to a process station, including: a sheet tray for holding the stack of sheets; an air plenum, positioned above the stack of sheets, for picking up a sheet from the stack of sheets when a vacuum force in the air plenum; a paper fluffer for blowing air between individual sheets in the stack.

Abstract: A sheet feeding apparatus for feeding a stack of sheets in a direction of movement to a process station, including: a sheet tray for holding the stack of sheets; an air plenum, positioned above the stack of sheets, for picking up a sheet from the stack of sheets when a vacuum force in the air plenum; a paper fluffer for blowing air between individual sheets in the stack, the paper fluffer having a system for adjusting air flow between individual sheets.

Abstract: A compact structure and rapid method for calibrating a document scanner provides for a substantially cylindrical calibration casing having a central axis and an outer surface, with a brightness calibration section of the outer surface encompassing a portion of the circumference of the outer surface, a document width detection segment encompassing a second portion of the circumference of the outer surface, and a document backer element encompassing a third segment of the circumference of the outer surface of the casing. A driver selectively positions the casing in different rotational positions in which the different segments of the outer surface of the cylinder face the optical element of the scanner.

Abstract: A sheet feeding apparatus for feeding a stack of sheets in a direction of movement to a process station, including: a sheet tray for holding the stack of sheets; an air plenum, positioned above the stack of sheets, for picking up a sheet from the stack of sheets when a vacuum force in the air plenum; a paper fluffer for blowing air between individual sheets in the stack.

Abstract: A sheet feeding apparatus for feeding a stack of sheets in a direction of movement to a process station, including: a sheet tray for holding the stack of sheets; an air plenum, positioned above the stack of sheets, for picking up a sheet from the stack of sheets when a vacuum force in the air plenum; a paper fluffer for blowing air between individual sheets in the stack, the paper fluffer having a system for adjusting air flow between individual sheets.

Abstract: A compact structure and rapid method for calibrating a document scanner provides for a substantially cylindrical calibration casing having a central axis and an outer surface, with a brightness calibration section of the outer surface encompassing a portion of the circumference of the outer surface, a document width detection segment encompassing a second portion of the circumference of the outer surface, and a document backer element encompassing a third segment of the circumference of the outer surface of the casing. A driver selectively positions the casing in different rotational positions in which the different segments of the outer surface of the cylinder face the optical element of the scanner.