Abstract: A printer is configured to detect a missing material drop in a top layer of a part being printed in the printer. Upon detection of a missing material drop, the printer moves the platform on which the part is being formed in a direction opposite to the process direction to position the area in which the drop is missing beneath an ejector that is operated to eject a drop in the area. This procedure is performed for each area in which a missing drop was detected before the next layer of the part is formed.

Abstract: A printer is configured to detect a missing material drop in a top layer of a part being printed in the printer. Upon detection of a missing material drop, the printer moves the platform on which the part is being formed in a direction opposite to the process direction to position the area in which the drop is missing beneath an ejector that is operated to eject a drop in the area. This procedure is performed for each area in a missing drop was detected before the next layer of the part is formed.

Abstract: Methods and systems print markings on a web of media using a printer to produce a printed roll of media. During the printing, the printer automatically analyzes the internal printer conditions, and automatically identifies printing errors based on the internal printer conditions during the printing. Further, such methods and systems automatically record the printing errors in an error log file using a computerized device that is operatively connected to the printer and store the error log file in a network storage element within a computerized network. Also, such methods and systems transmit the error log file from the computerized device (or the network storage element) to a post-printing processing device using the computerized network after receiving a request for the error log file. The post-printing processing device unwinds the printed roll and automatically stops the unwinding process at locations of the printing errors based on the error log file.

Abstract: Methods and systems print markings on a web of media using a printer to produce a printed roll of media. During the printing, the printer automatically analyzes the internal printer conditions, and automatically identifies printing errors based on the internal printer conditions during the printing. Further, such methods and systems automatically record the printing errors in an error log file using a computerized device that is operatively connected to the printer and store the error log file in a network storage element within a computerized network. Also, such methods and systems transmit the error log file from the computerized device (or the network storage element) to a post-printing processing device using the computerized network after receiving a request for the error log file. The post-printing processing device unwinds the printed roll and automatically stops the unwinding process at locations of the printing errors based on the error log file.

Abstract: Registering a first image on a first side of a substrate with a second image on a second side. A motor driven document transport advances a substrate to a transfer station that transfers the first image onto the substrate. The substrate is then inverted and the document transport moves the inverted substrate back to the transfer station to receive a second image. A sensor detects a leading edge and a trailing edge of the substrate, while an encoder operatively connected to the motor produces a predetermined number of pulses per revolution. A counter counts the number of encoder pulses between the leading edge and the trailing edge. The controller then determines the width of the substrate from the number of counted encoder pulses and from the distance the substrate advances per encoder pulse. The controller then controls the document transport to position the substrate at the transfer station such that the second image is registered with the first image.

Abstract: A technique for saving data related to given machine events in a control that normally records machine events or faults in a first-in, first-out buffer of finite size called an occurrence log by selectively setting the control to respond to the occurrence of a given machine fault or event, monitoring the operation of the machine for the occurrence of the given machine event, and initiating the transfer of the data in the buffer to a nonvolatile memory. Also included is the technique of delaying the transfer of the data in the buffer memory to the non-volatile memory until the recording of a given set number of events is determined in the buffer.

Abstract: A technique is provided for controlling the interposition of one or more special sheets into a stream of regular imaged substrates. In one example, a point in time at which a special insert sheet should be fed from a special insertion sheet subsystem to the stream is determined by reference to plural sets of preset time periods. In this example, the preset time periods can be adjusted to accommodate print engine/interposing module machine clock fluctuations. In another example, interposition of a special insert sheet with the stream of regular imaged substrates is maintained at an acceptable level by comparing a distance between a special insert sheet fed to the stream and an adjacent regular imaged substrate with a predefined tolerance. The comparison can then be used to adjust feed times of special insert sheets subsequently fed to the stream.

Abstract: An apparatus for sensing the presence or an edge of a sheet, including a light emitter, a set of reflectors and at least one light detecting member. A light beam is reflected between the emitter and detector in a repeating wave form so as to intersect a sheet path; interruption of the light beam indicates the presence of a sheet. False indications of the presence, absence or true edge of the sheet such as may be caused by sheet holes or edge irregularities are avoided by the multiple passes of a beam of light across the path of the sheet. A continuous cleaning action of the sensor may be provided by the movement of the sheet over the light emitters, light detectors and/or reflectors. The sheet sensors are useful in detecting and/or correcting sheet skew, misregistration and other potential sheet handling problems.

Abstract: A method of purging copy sheets after a machine malfunction from a copy sheet path having a plurality of zones including the steps of determining the existence of copy sheets in process in any of the copy sheet path zones, selectively activating a plurality of independent copy sheet drives to maintain a predetermined interdocument space between any copy sheets in process and systematically purging the copy sheets from the zones of the paper path in a predetermined order based upon the particular disposition of the copy sheets in the sheet path zones.