Abstract: Embodiments described herein are directed to a system for reducing electrostatic fields underneath print heads in a direct marking printing system. The system includes: one or more print heads for depositing ink onto a media substrate; a media transport for moving the media substrate along a media path past the one or more print heads; a conductive platen contacting the media transport belt; and an electrostatic field reducer that includes an alternating current corona device positioned upstream of the one or more print heads. The media transport includes a media transport belt and, when the media substrate is on the transport belt it has an electrostatic field, which can cause printing defects. The electrostatic field reducer reduces the electrostatic field on the surface of the media substrate and thereby reduces printing defects.

Abstract: Embodiments described herein are directed to a system for reducing electrostatic fields underneath print heads in a direct marking printing system. The system includes: one or more print heads for depositing ink onto a media substrate; a media transport for moving the media substrate along a media path past the one or more print heads; a conductive platen contacting the media transport belt; an electrostatic field reducer that includes an alternating current charge device positioned upstream of the one or more print heads; and one or apertures with electrically isolated biased electrodes separated by an opening that is in registration with the ink deposition areas of the one or more print heads. The media transport includes a media transport belt and, when the media is on the transport belt it has an electrostatic field, which can cause printing defects. The electrostatic field reducer and electrodes reduce the electrostatic field on the surface of the media and thereby reduce printing defects.

Abstract: An imager apparatus useful for a digital lithographic printing system includes imaging roll configured to be heated to a first temperature. The imager apparatus may include one or more heating elements for heating the imaging roll to the first temperature within one revolution. The imaging roll may be about the same width as an imaging plate in a cross-process direction, the imaging plate and the imaging roll being configurable for forming an imaging nip in a digital lithographic ink printing system. The imager apparatus may include a solution ejecting mechanism such as a printhead for ejecting fountain solution or water at ambient temperature onto a surface of the imaging roll according digital image data.

Abstract: An imager apparatus useful for a digital architecture lithographic printing system includes a first imager bank having at least one imager configured to produce a first output beam; and a second imager bank having at least one imager configured to produce a second output beam, the second imager bank being located at a first angle with respect to the first imager bank, the first output beam and the second output beam being separated by a second angle which is less than the first angle.

Abstract: A printer and method of printing wherein a preview mode conveys media through the printer in a manner that avoids the possibility that the media can contact a print head. A hold-down system of the printer and/or media transport generates a hold-down pressure applied to the substrate media in the direction of the first media transport. A precurler unit applies a predetermined degree of curl to the substrate media. A media height sensor determines the height of the substrate media above the first media transport under the influence of the hold-down pressure. A print head array marks the substrate media with an image in the marking zone, and an actuator adjusts the relative spacing between the print head array and the first media transport. The gap between print head and the media is adjustable in view of the measurements.

Abstract: A reversing apparatus within a media path comprises an input nip moving sheets of media in a first direction, and a reversing nip positioned to receive the sheets of media from the input nip. The reversing nip stops the sheets and moves the sheets in a second direction opposite the first direction. Also included is an output nip positioned to receive the sheets of media from the reversing nip, and an actuator connected to the reversing nip. The actuator moves the reversing nip relative to a position of the input nip and the output nip, based on a characteristic of the sheets of media.

Abstract: A media transport apparatus and method includes a first media transport having a first drive unit, configured and operative to convey the substrate media through a marking zone to be marked by a print head. A first motion encoder is operatively connected with the first media transport, configured and operative to output a first signal dependent upon the motion of the first media transport surface. A second media transport with a second drive unit and second motion encoder is configured and operative to receive the substrate media from the first media transport and to convey the substrate media. The second drive unit drives the motion of the second media transport with substantially the same surface velocity as the first media transport.

Abstract: This invention generally relates to accurately measuring image geometries in-line within a printing system. One or more two-dimensional array sensors may be located adjacent to a sheet of media printed with a predefined array of indicia marks so that the sensor field of view is contained within the plane of sheet transport. As the sheet is transported by the sensor, the sensors continuously record the locations of the indicia marks within its field of view. The spatial frequency of the indicia marks is arranged so that at least two indicia marks are within the field of view of the sensor at any instant for each of the process and cross-process directions. The two-dimensional array sensor can thus measure the absolute spacing between adjacent local indicia marks within the precision of the sensor construction. The cumulative spacing along each direction may then calculated to determine the overall dimensions of the indicia marks array.

Abstract: Described herein is an exemplary method wherein the photoreceptor surface velocity is nominally set at a speed fractionally different than the intermediate belt (ITB) nominal surface speed. The photoreceptor speed can be preemptively altered through a velocity ramp profile whenever an event is scheduled to occur that will result in ITB transient vibration. As a result, the photoreceptor speed is not allowed to cross over or equal the belt speed at any instant during the transient event. This allows the photoreceptor to remain dynamically decoupled from the ITB, since the apparent disturbance torque imposed by the belt remains constant and does not reverse sign.

Abstract: A media sheet transport including a belt for supporting the media thereon. The belt is operably connected to a drive mechanism for moving the belt in a process direction past an image marking unit. The belt has a plurality of openings therein. A vacuum plenum has a surface disposed below the belt and is operably connected to a vacuum source. The vacuum plenum is adapted to applying a negative pressure to the media for holding the media to the belt. An electrostatic hold down apparatus includes a first tacking roller spaced in a cross-process direction from a second tacking roller. The first and second tacking rollers are engagable with the belt. The first tacking roller is disposed to engage the inboard edge of the media, and the second tacking roller is disposed to engage the outboard edge of the media. The first and second tacking rollers impart an electrostatic charge to the edges of the media for electrostatically securing the inboard and outboard edges of the media to the belt.

Abstract: A media transport apparatus and method includes a first media transport having a first drive unit, configured and operative to convey the substrate media through a marking zone to be marked by a print head. A first motion encoder is operatively connected with the first media transport, configured and operative to output a first signal dependent upon the motion of the first media transport surface. A second media transport with a second drive unit and second motion encoder is configured and operative to receive the substrate media from the first media transport and to convey the substrate media. The second drive unit drives the motion of the second media transport with substantially the same surface velocity as the first media transport.

Abstract: A media sheet transport including a belt for supporting the media thereon. The belt is operably connected to a drive mechanism for moving the belt in a process direction past an image marking unit. The belt has a plurality of openings therein. A vacuum plenum has a surface disposed below the belt and is operably connected to a vacuum source. The vacuum plenum is adapted to applying a negative pressure to the media for holding the media to the belt. An electrostatic hold down apparatus includes a first tacking roller spaced in a cross-process direction from a second tacking roller. The first and second tacking rollers are engagable with the belt. The first tacking roller is disposed to engage the inboard edge of the media, and the second tacking roller is disposed to engage the outboard edge of the media. The first and second tacking rollers impart an electrostatic charge to the edges of the media for electrostatically securing the inboard and outboard edges of the media to the belt.

Abstract: A media transport apparatus includes a first media transport, having a first transport surface and a first drive unit, to convey the substrate media. A second media transport having a second transport surface and a second drive unit receives the substrate media from the first. A first force transducer outputs a force signal associated with a first force between the media transports. A control unit receives the force signal, and outputs a control signal to at least one of the first and second drive units that is dependent upon a comparison of the first relative force signal with a predetermined value. The control signal commands the first or second drive unit to drive the motion of the respective first or second media transport to maintain the force signal at or about no greater than the predetermined value.

Abstract: A monitoring system and method for monitoring a printing system includes a printing system module and a camera. The printing system module is configured to interface with a primary printing-medium path of the printing system and includes a housing with at least one printing-medium path disposed therein. The at least one printing-medium path is a sub-printing-medium path of the primary printing-medium path. The camera is positioned to capture at least one frame of the inside of the printing system module and can be disposed therein.

Abstract: Embodiments described herein include an upstream measurement module, a curler downstream of the upstream measurement module, and a print station downstream of the curler. The upstream measurement module includes a transport on which media is tacked to flatten the media and a curl sensor to generate a curl signal corresponding to a media curl of the media on the transport. The curler curls the media in response to the curl signal to reduce a magnitude of the media curl. The print station includes a marking unit to dispose a marking material on the media and a transport to transport the media past the marking unit, wherein the first and second transports apply a substantially equivalent hold down force to the media.

Abstract: A finishing unit includes a first compiling module and a second compiling module operatively connected in parallel with the first compiling module. Each compiling module includes a finishing head adapted to perform a finishing operation upon a plurality of sheets of media. A printing system includes a sheet media source, a finishing unit operatively spaced from the sheet media source and a marking unit operatively disposed therebetween. A method of performing a print job using such first and second compiling modules is also included.

Abstract: Described herein is an exemplary method wherein the photoreceptor surface velocity is nominally set at a speed fractionally different than the intermediate belt (ITB) nominal surface speed. The photoreceptor speed can be preemptively altered through a velocity ramp profile whenever an event is scheduled to occur that will result in ITB transient vibration. As a result, the photoreceptor speed is not allowed to cross over or equal the belt speed at any instant during the transient event. This allows the photoreceptor to remain dynamically decoupled from the ITB, since the apparent disturbance torque imposed by the belt remains constant and does not reverse sign.

Abstract: A system for support, operation, installation, and removal of an endless belt in a scalable modular printing system includes an input module, at least one marking module, and an output module. The endless belt is an intermediate transfer belt, a photoconductive belt, or a sheet transport belt used in the marking system. Rollers support an interior surface of the belt, and are supported by their respective module frame structures, thus defining a vacant interior cavity of the belt. A method of belt installation includes drawing all interior rollers out of their frame structures, placing the pre-scrolled belt at one end module of the system, uncoiling the belt along its process direction within the internal cavity of the system, then reinstalling the interior rollers to capture the belt into its operating position.

Abstract: This invention provides a method to strip a media sheet that is adhered to an image carrying belt surface so that the sheet can follow the subsequent intended path through a marking system. The belt can be a photoconductor belt or an intermediate transfer belt. The stripping feature of this invention is located movably adjacent to a back-up roll in a transfer station of the marking system. The stripping feature has a radiused belt contact portion. After the sheet has an image transferred thereon from the belt, sometimes the sheet adheres to the belt, which can be disruptive to the system. This invention provides that the stripping feature can be selectively deployed so that its radiused belt contact portion presses against the inside of the image carrying belt, thus temporarily deforming the belt and thereby causing the sheet to release therefrom.

Abstract: A drive roll/idler roll nip release mechanism utilizes the motor used for the drive nip, coupled with one-way clutches, to power the nip release as a sheet is handed off to a downstream nip. A drive shaft is coupled to a first one-way clutch in one direction and an idler cam shaft is coupled to a second one-way clutch in the opposite direction. This allows the idler cam shaft to be driven only when the motor is reversed, and the drive shaft to be driven only when the motor is moving forward. The one-way clutch on the drive shaft allows the drive wheels to freewheel when the motor is reversed in order to engage the nip release. Thus, the nip release is activated while the drive nip continues to rotate in the direction of sheet motion.