Hewlett-packard Development Company, L.p.

Hewlett-packard Company

E.i. Dupont De Nemours and Company

David Herbert Donovan

Jacob Wright

Keshava A Prasad

John L Stoffel, Jr

Winthrop D Childers

Pavel Kornilovich

Brian J Keefe

Alejandro Manuel De Pena

Steven Warren Steinfield

Steven L Webb

Kenneth J Courian

Erica Montei Fung

Jules G Moritz

Behnam Bastani

Shilin Guo

Richard A Sader

Krzysztof Nauka

Ali Emamjomeh

John R Moffatt

Stephen William Bauer

Francesc Subirada

Kevin R Hudson

Loren E Johnson

Miquel Boleda

Johan Maurice Lammens

Glenn Thomas Haddick

Dale Dean Timm, Jr

Hua Tan

David Luis Pereira

Bryan S Ly

John A Dangelawicz

Behnam Baslani

Jacob Tyler Wright

Jacob T Wright

A three-dimensional object may be generated. A controller may be to control an energy source to apply energy to a layer of build material on a support member or previous layer to cause a portion of the layer to coalesce and solidify to form a slice of the three-dimensional object. A radiation sensor may be to measure absorbance or gloss of the layer. The controller may be to receive, from the radiation sensor, data representing measured absorbance or measured gloss of the layer. The controller may be to control the apparatus to modify a process parameter if the measured absorbance or gloss indicates an incorrect degree of solidification of a part of the layer.

Generating three-dimensional objects

A three-dimensional object may be generated. Coalescing agent may be selectively delivered on a portion of a first layer of build material on a support member or previous layer. Energy may be applied to the first layer to cause the portion of the first layer to coalesce and solidify. A second layer of the build material may be provided on the first layer. While the second layer does not have coalescing agent delivered thereon, energy may be applied to the second layer such that energy may propagate through the second layer to the first layer to cause the portion of the first layer to coalesce and further solidify.

In an example, an apparatus for generating a three-dimensional object includes a build area platform, a build material distributor, a secondary material ejection device, a coalescing agent ejection device, and a controller. The controller may control the secondary material ejection device to eject a secondary material in a predefined pattern over the build area platform, control the build material distributor to distribute a layer of the build material around the ejected secondary material, control the coalescing agent ejection device to eject the coalescing agent onto the layer of the build material, and control an energy source to apply energy onto the ejected coalescing agent to cause the build material in contact with the ejected coalescing agent to coalesce and solidify.

Generating a three-dimensional object

Agent calibration can, in an example implementation, include generating a calibration based on a quantity of energy absorbed by a build material treated with different quantities of an agent and converting a portion of a three-dimensional object model to a quantity of agent based on the calibration.

Agent calibration

A method of forming a three-dimensional object includes non-deterministically generating halftone data for portions of a slice of three-dimensional model data of the three-dimensional object that overlap with a previous slice. The non-deterministically generating halftone data may comprise using randomized initialization for each slice of a three-dimensional object.

Generating halftone data for a three-dimensional object

Adjustment of a halftoning threshold can, in an example implementation, include assigning a relative energy value, relative to a reference energy value, to a location of a build area and adjusting a halftoning threshold based on the relative energy value.

Adjustment of a halftoning threshold

In a computational modeling method for identifying how to apply a modifying agent during a three-dimensional (3D) printing method, a thermal diffusion model of a layer of a 3D object to be formed from a portion of a sinterable material using the 3D printing method is created. The thermal diffusion model is created by a computer running computer readable instructions stored on a non-transitory, tangible computer readable storage medium. A quantity of the modifying agent to be selectively applied is calculated, by the computer, based upon the thermal diffusion model.

Computational model and three-dimensional (3D) printing methods

A method of diffusing an error in three-dimensional contone model data includes generating halftone data for a slice among a number of slices of the three-dimensional contone model data, generating compensatory error values based on the generated halftone data, and adding the generated compensatory error values to contone data for a successive slice.

Diffusing an error in three-dimensional contone model data

An additive manufacturing system may include a controller to determine an emissivity of a portion of a layer of build material based on a measured optical property of the portion, or based on object design data representing a degree of intended solidification of the portion. The controller may be to determine a temperature of the portion based on the determined emissivity and a measured radiation distribution emitted by the portion.

Temperature determination based on emissivity

A method for halftone printing of an image may include receiving image data of an image to be printed. The method may also include processing the image data to generate, for each printing element of a plurality of printing elements which are designed to sharingly print a single color component of a color space, or for each pass of a single printing element which is designed to pass a plurality of passes over a single print area when printing that color component, a halftone pattern for the image for that color, that was independently generated for that printing element or for that pass. The method may further include printing, by each printing element of the plurality of printing elements or in each pass of a single printing element, the halftone pattern that was independently generated for that printing element or for that pass.

Method and system for halftone printing

Embodiments of printer optical sensing error determination are disclosed.

Printer optical sensing error determination

A printer is disclosed in one example. The printer controls the amounts of the inks that are used when printing. The printer prints colors near saturation onto a media using mostly a first ink and prints saturated colors onto the media using mostly a second ink. The second ink has a reduced loading of the colorant in the first ink.

Printing near saturation

A method for density error correction is disclosed. In one embodiment, the method includes a) calculating an average density error for at least one row of an image considering density errors for printhead elements employed to print the at least one row, and a number of passes that the printhead elements will utilize to print the at least one row, b) calculating a density error correction value for the at least one row considering the average density error, and c) applying the density error correction value to adjust ink flow from the printhead elements while printing the at least one row.

Density error correction

An ink-jet printing system includes an ink set having only cyan, magenta, yellow black and gray inks, and a medium having a substantially neutral color. A ratio of printed lightness of the gray ink to a lightness of the medium ranges from 0.3 to 0.7.

Growing community of inventors

San Diego, CA, United States of America

David Herbert Donovan