Abstract: A three-dimensional object printer ejects drops of a build material from a plurality of ejectors in a first printhead to form an object on a first region of a member and ejects drops of a support material from a plurality of ejectors in a second printhead to support the object on the first region of the member. The second printhead ejects drops of the support material onto a second region of the member that is separate from the first region to form a substrate layer. The first printhead ejects drops of the build material onto the substrate layer to form a printed test pattern. An image sensor generates image data of the printed test pattern to identify an inoperable ejector in the first printhead.

Abstract: A method for dynamically compensating for thermal expansion and contraction of a light emitting diode print bar having first and second light emitting diodes having first and second ideal positions, respectively, the method including: a) determining a first measured position of the first light emitting diode and a second measured position of the second light emitting diode; b) comparing the first measured position and the second measured position to the first ideal position and the second ideal position, respectively; and, c) correcting a first difference between the first measured position and the first ideal position and a second difference between the second measured position and the second ideal position based on results from the step of comparing.

Abstract: A method for dynamically compensating for thermal expansion and contraction of a light emitting diode print bar having first and second light emitting diodes having first and second ideal positions, respectively, the method including: a) determining a first measured position of the first light emitting diode and a second measured position of the second light emitting diode; b) comparing the first measured position and the second measured position to the first ideal position and the second ideal position, respectively; and, c) correcting a first difference between the first measured position and the first ideal position and a second difference between the second measured position and the second ideal position based on results from the step of comparing.

Abstract: A printer compensates for variations in ejected material drop volumes occurring during production of the layers for the formation of an object in a three-dimensional printer. The printer includes an optical sensor that generates topographical and measurement data of each layer of the object after each layer is printed. Differences in height between columns of material being formed by the ejectors in the printhead are identified with reference to the data produced by the sensor and raster data used to operate the printhead are modified adjust the formation of a next layer in the object.

Abstract: A printer uses closed loop control to keep material drops ejected by a printhead within a predetermined range. The printer forms at least two objects on a support member and then operates a specular sensor array to obtain image data of the two objects on the support member. The two objects have different predetermined heights to enable a controller in the printer to identify the mass or volume of the material drops forming the objects to adjust operational parameters of the printer to maintain the mass or volume of the material drops in the predetermined range.

Abstract: A system for focusing light including a gradient index lens array positioned at a first distance from a surface, and first and second positioning elements arranged to modify the first distance. The first and second positioning elements modify the first distance based on an analysis of an image formed on the surface across substantially a full width of a cross process direction of the surface.

Abstract: A printer compensates for printing errors occurring during production of the layers for the formation of an object in a three-dimensional printer. The printer includes an optical sensor that generates data corresponding to edges of each layer of the object after each layer is printed. Differences between the raster data used to eject the material to form a layer and the data received from the optical sensor are used to modify the raster data that operates a printhead to form a next layer in the object.

Abstract: A three-dimensional object printer ejects drops of a build material from a plurality of ejectors in a first printhead to form an object on a first region of a member and ejects drops of a support material from a plurality of ejectors in a second printhead to support the object on the first region of the member. The second printhead ejects drops of the support material onto a second region of the member that is separate from the first region to form a substrate layer. The first printhead ejects drops of the build material onto the substrate layer to form a printed test pattern. An image sensor generates image data of the printed test pattern to identify an inoperable ejector in the first printhead.

Abstract: A printer compensates for variations in ejected material drop volumes occurring during production of the layers for the formation of an object in a three-dimensional printer. The printer includes an optical sensor that generates topographical and measurement data of each layer of the object after each layer is printed. Differences in height between columns of material being formed by the ejectors in the printhead are identified with reference to the data produced by the sensor and raster data used to operate the printhead are modified adjust the formation of a next layer in the object.

Abstract: A printer compensates for printing errors occurring during production of the layers for the formation of an object in a three-dimensional printer. The printer includes an optical sensor that generates data corresponding to edges of each layer of the object after each layer is printed. Differences between the raster data used to eject the material to form a layer and the data received from the optical sensor are used to modify the raster data that operates a printhead to form a next layer in the object.

Abstract: A semi-conductor chip for a print head, including: a plurality of LEDs; a drive circuit for supplying electrical power to the plurality of LEDs; and a control system calibrated to supply, using the drive circuit, the electrical power at a first magnitude to every LED in the plurality of LEDs and configured to: receive a first external clock pulse less than a second external clock pulse used to calibrate the plurality of LEDs; change the first magnitude to at least one second magnitude proportional to the first external clock pulse; receive a third external clock pulse different from the first and second external clock pulses; and energize, using the drive circuit and in response to the third external clock pulse, the plurality of LEDs for a first internal strobe time at the at least one second magnitude calculated by the control system.

Abstract: A semi-conductor chip for a print head, including: a plurality of LEDs; a drive circuit for supplying electrical power to the plurality of LEDs; and a control system calibrated to supply, using the drive circuit, the electrical power at a first magnitude to every LED in the plurality of LEDs and configured to: receive a first external clock pulse less than a second external clock pulse used to calibrate the plurality of LEDs; change the first magnitude to at least one second magnitude proportional to the first external clock pulse; receive a third external clock pulse different from the first and second external clock pulses; and energize, using the drive circuit and in response to the third external clock pulse, the plurality of LEDs for a first internal strobe time at the at least one second magnitude calculated by the control system.

Abstract: A printer uses closed loop control to keep material drops ejected by a printhead within a predetermined range. The printer forms at least two objects on a support member and then operates a specular sensor array to obtain image data of the two objects on the support member. The two objects have different predetermined heights to enable a controller in the printer to identify the mass or volume of the material drops forming the objects to adjust operational parameters of the printer to maintain the mass or volume of the material drops in the predetermined range.

Abstract: LED printhead apparatus and printing systems are presented in which an LED array and a first high angle lens array are housed in an LED printbar assembly and a second low angle lens array is provided between the first lens array and a photoreceptor belt or drum in order to relay the output of the first lens array to the photoreceptor to provide a larger depth of focus and to reduce waterfront and tolerance issues near the photoreceptor.

Abstract: LED printhead apparatus and printing systems are presented in which an LED array and a first high angle lens array are housed in an LED printbar assembly and a second low angle lens array is provided between the first lens array and a photoreceptor belt or drum in order to relay the output of the first lens array to the photoreceptor to provide a larger depth of focus and to reduce waterfront and tolerance issues near the photoreceptor.

Abstract: A device including: a photoreceptor; an LED printbar; and a computer processor for: determining how long LEDs on the printbar are energized while the device is operated to generate an image output; determining that a first plurality of LEDs has been energized less than a second plurality of LEDs; energizing the first plurality of LEDs for a correction time period as the LEDs are aligned with an inter-document zone (IDZ); and de-energizing the second plurality of LEDs during the time period. Energizing the second plurality of LEDs is unrelated to energizing the LEDs for purposes of evaluating an image. The time period is concurrent with operation of the device to generate an image output.

Abstract: A phase change inkjet printer is equipped with an agitator to prevent settling of metal particles in melted magnetic phase change ink. The agitator operates to agitate the melted magnetic phase change ink as the ink enters the printhead to maintain the metal particles in suspension within the melted ink.

Abstract: A printhead wiper assembly includes an elongated member having a first and second wiper, a linkage, and an actuator. The linkage includes a clutch that enables the elongated member to move to a plurality of positions in response to the actuator activating a plurality of times. The sequence of positions enables first wiper and then the other wiper to contact the printhead face to remove purged ink from the face.

Abstract: A method of performing maintenance on printheads of an imaging device includes the detection of at least one missing or defective inkjet in a printhead. A first pressure is applied to ink in printheads in which at least one missing or defective inkjet was detected. The first pressure is configured to discharge ink from the plurality of apertures in an aperture plate of the printhead to reestablish fluid continuity through the inkjet. A second pressure is applied to all of the printheads to be wiped. The second pressure is configured to form a convex meniscus at the plurality of apertures in the aperture plate of all of the printheads to be wiped. A single actuator is then operated to move one or more wipers into engagement with the printheads to be wiped. During wiping the convex meniscus is encountered by a wiper to lubricate a printhead and prevent the printhead from being damaged by wiping. The single actuator then retracts the one or more wipers from the printheads.

Abstract: A phase change inkjet printer is equipped with an agitator to prevent settling of metal particles in melted magnetic phase change ink. The agitator operates to agitate the melted magnetic phase change ink as the ink enters the printhead to maintain the metal particles in suspension within the melted ink.