Abstract: In one embodiment, an inkjet printer includes: a first series of print bars arranged along an arc on a first side of an arched printing unit and a second series of print bars arranged along an arc on a second side of the arched printing unit and a dryer positioned within a footprint of the arched printing unit. A plurality of web guides are arranged to guide the web along a duplex printing path past the first print bars for printing on a first side of the web, then through the dryer for drying the first side of the web, then past the second print bars for printing on a second side of the web, and then through the dryer for drying the second side of the web.

Abstract: 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.

Abstract: In one embodiment, an inkjet printer includes: a first series of print bars arranged along an arc on a first side of an arched printing unit and a second series of print bars arranged along an arc on a second side of the arched printing unit and a dryer positioned within a footprint of the arched printing unit. A plurality of web guides are arranged to guide the web along a duplex printing path past the first print bars for printing on a first side of the web, then through the dryer for drying the first side of the web, then past the second print bars for printing on a second side of the web, and then through the dryer for drying the second side of the web.

Abstract: A printhead for an inkjet printer having geometric features which reduce drop placement error of main and satellite drops ejected from the nozzles of the printhead. Nozzles that are tilted along an axis corresponding to the direction of scanning of the printhead while printing have reduced drop placement error in the orthogonal direction to the scanning, and create a breakoff velocity for the satellite drop that can cause the main and satellite drops to be placed in a coincident location on the medium in one of the directions of scanning, thus forming desireable round printed spots and reducing drop placement error in the scan direction. These improvements can be repeatably achieved for all nozzles. Nozzles with non-circular and asymmetric bores also reduce drop placement errors, particularly when these types of nozzles are also tilted.

Abstract: An embodiment of a temperature compensations system at least partially compensates for temperature induced changes in the mass of drops ejected from printheads in an inkjet printer. A value representing the temperatures of cyan, magenta, yellow, and black printheads is provided to a controller. Using these values, the controller adjusts KCMY color values associated with each pixel to form transformed color values for a swath. A halftone operation is performed upon these transformed color values for the swath. The results of the halftone operation are used by the controller to determine the printheads that must eject drops of ink onto the pixels within the swath and to determine the number of passes of the printheads across the swath to form the portion of the image on the media corresponding to the swath.

Abstract: The present invention includes as one embodiment a method of controlling an inkjet printhead assembly, including providing the printhead assembly having ink ejection elements that eject ink from a firing chamber through a nozzle and being energizable by an electrical pulse having a first predetermined energy, monitoring the printhead assembly to determine elapsed time since each ink ejection element on the printhead assembly has been fired, calculating a predetermined maximum amount of time that an ink ejection element is not operating using ink formulation and geometry of the nozzle and the firing chamber, comparing the elapsed time for each ink ejection element on the printhead assembly with the predetermined maximum amount of time and initiating high energy spitting at a second predetermined energy for the printhead assembly if the predetermined maximum amount of time has been exceeded for at least one of the ink ejection elements on the printhead assembly.