Hewlett-packard Development Company, L.p.

Luke P Sosnowski

Justin M Roman

Alexander Toia

Wesley R Schalk

Mark H MacKenzie

Arthur H Barnes

Pierre Joseph Kaiser

David Soriano

Saurabh Shripad Bhide

Erich Waldherr Hacker

Rafael Gonzalez

Emiliano Gabriel Tolosa Gonzalez

Robert M Yraceburu

Bruce G Johnson

Warren K Harwood

Louis C Barinaga

Raymond C Sherman

Robert Lawrence Winburne

Joseph Emery

Hsue-Yang Liu

Randall West

Scott Martin

Peter J Boucher

Gary T Strowe

Richard Scott Smith

Kynan Lon Church

Jason Young Carothers

Michael Rode

Mike Fairchild

Gabriel Michael Rask Gassoway

Allan G Olsen

Nicholas Wang

Steve A O'hara

Jason Y Carothers

Michael James Rode

In one example, a build material recovery system for additive manufacturing includes: a receiving station to receive a portable container containing a build material; a separator to remove build material from a stream of air; a first conduit to carry build material in the stream of air from the receiving station to the separator; a source of negative air pressure to pull the stream of air with the build material through the first conduit from the receiving station to the separator; a humidifier to add moisture to the stream of air; and a second conduit to carry build material from the separator to the receiving station.

Humidification in a build material recovery system

Techniques for controlling moisture content of build material in a three dimensional printer are provided. An example system includes a build material vessel to contain the build material and receive a flow of air, and a humidifier to adjust the humidity of the air flowing into the build material vessel. The system also includes one or more sensors to determine a dew point of the air flowing into the build material vessel. The humidity level of the air flowing into the hopper is controlled by the humidifier to maintain the dew point at a level that will prevent condensation of water inside the build material vessel.

Controlling moisture content of build material in a three-dimensional (3D) printer

Example printer finishing apparatus are described herein. An example printer disclosed herein includes an alignment guide, a track to align a sheet relative to the alignment guide, a clamp to move between a raised position and a lowered position relative to the sheet, and a force applicator coupled to the clamp. The force applicator is to cause the sheet to engage the alignment guide when the clamp is in the lowered position.

Printer finishing apparatus

A system for manufacturing three dimensional objects can include logic to apply a gas with at least one flow rate to a vessel of a three dimensional printer. The logic can also detect a permeability of a build material residing within the vessel, wherein the permeability is calculated based on a plurality of pressure values detected by a plurality of pressure sensors residing in the vessel, and apply the gas with a predetermined humidity level at a second flow rate to modify the permeability of the build material residing in the vessel. Furthermore, the logic can initialize manufacturing a three dimensional object with the build material in response to detecting the permeability of the build material is below a predetermined threshold.

Three-dimensional (3D) object printing based on build material permeability

A system for manufacturing three dimensional objects can include logic to detect, for at least one vessel, a moisture content level corresponding to a build material residing in the at least one vessel. The logic can also adjust a humidity level and a temperature of a gas and a conditioning agent applied to the at least one vessel, wherein the humidity level and the temperature are based on the moisture content level and a temperature of the build material residing in the at least one vessel. Additionally, the logic can initialize manufacturing a three dimensional object with the build material from the at least one vessel in response to detecting the moisture content level of the build material residing in the at least one vessel is within a predetermined range.

Three-dimensional (3D) object printing based on a build material, moisture content level

In some examples, a build material recycling system of a three-dimensional (3D) printer can include a build material transport system of the 3D printer, a build material recycling device of the 3D printer that includes a fluidizing membrane and is connected to the build material transport system, and a recycled build material hopper of the 3D printer connected, via the build material transport system, to the build material recycling device.

Build material recycling system of a three-dimensional (3D) printer

Examples described herein include examples print media handling system including a first media guide assembly comprising a sensor assembly, and a second media guide assembly comprising a retractable pressure plate and disposed opposite the first media guide assembly to guide a print media along a path between the first media guide assembly and second media guide assembly, the pressure plate moveable about an axis perpendicular to the path between an actuated position and a retracted position.

Print media pressure plates

Media skew correction is performed by determining a leading edge skew value for the media and selecting a respective media model from a memory for a media type, each media model including a paired slope and an intercept. Based on the paired slope and intercept for the respective media model, differential velocity of a pair of aligned media feed rollers in a media feed mechanism is adjusted to correct a trailing edge skew for the media to within a desired operational window.

Media skew correction

In one example implementation, a printing device may comprise a number of media skewing rollers to skew a print medium to a predetermined angle with respect to a media feed path and a print engine to print an image on the skewed print medium, the print engine skewing a digital representation of the image based on the predetermined angle such that the image printed is aligned with the print medium. In another example implementation, a printing device may comprise a number of skewing rollers to skew a print medium to a predetermined angle with respect to a media path, a number of pinch rollers to receive the skewed print medium prior to printing, and a print engine skewed to the same predetermined angle as the skewed print medium.

Skewing print medium

A media alignment calibration system determines a slope relating a trailing edge skew value to its paired leading edge skew value and an intercept representing native skew based on a linear regression of a predetermined number of a set of paired leading and trailing edge skew values for a media type stored in a buffer. Based on the slope and intercept, a media model for the media type is updated based on the linear regression to adjust a differential velocity of a pair of aligned media feed rollers in a media feed mechanism to correct both a future native skew and future paired leading and trailing edge skew values in the buffer to within a desired operational window.

Media alignment calibration

A skew sensor calibration unit including a scanner providing a scanned image of a sheet as the sheet is conveyed along a transport path, the scanned image including a leading edge of the sheet and a skew detection pattern printed thereon by a printhead. A calibration module measures a top skew of the sheet based on position signals from a plurality of skew sensors indicating a position of a leading edge of a sheet as the sheet is conveyed along the transport path, measure an image skew of the sheet relative to the printhead based on the scanned image, and generates a calibration factor that when applied to the measured top skew provides a calibrated top skew that matches the image skew.

Skew sensor calibration

In some examples, printing device performance management may include determining a physical media feed motor speed of operation for a physical media feed motor for a printing device including the physical media feed motor for transferring a physical medium within a print zone of the printing device, and a further motor for transferring the physical medium towards the print zone. For each physical medium that is to be transferred towards the print zone, the further motor may be actuated to transfer the physical medium at a further motor speed that is greater than the physical media feed motor speed to reduce a further motor duty cycle.

Printing device performance management

A printing system includes a printhead to eject ink onto a print medium in a print zone. A first roller pair is adjacent to the print zone to advance a print medium into the print zone. A second roller pair upstream from the first roller pair, and driven by an independent motor, advances the print medium to the first roller pair in a position control mode. A controller causes the second roller pair to switch from the position control mode to a force control mode when a leading edge of the print medium reaches the first roller pair. The second roller pair applies a substantially constant force to the print medium in the force control mode to push the leading edge of the print medium against the first roller pair while the first roller pair is stationary.

Printing system with force control mode

A method for media jam clearing includes detecting a media jam with sensor in the printer, in which the media jam comprises a sheet of media stuck in a media path of the printer. The method further includes monitoring for user action that alters the mechanically alters the state of the printer and detecting a user action that mechanically alters the state of the printer. In response to detection of the user action, the printer automatically attempts to clear the media jam.

Media jam clearing

A shaft for a media transport assembly includes a first assembly provided at a first end of the shaft to datum the shaft, and a second assembly provided at a second end of the shaft to bias the shaft in a direction opposite the second end of the shaft such that the first assembly and the second assembly each provide point contact with a respective surface oriented substantially perpendicular to an axis of the shaft.

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Vancouver, WA, United States of America

Luke P Sosnowski