Hewlett-packard Company

E.i. Dupont De Nemours and Company

David H Donovan

Gregg A Lane

Stefano Schiaffino

Chaucer C Tang

Sebastia Castelltort

Mark S Hickman

Larrie A Deardurff

Paul David Gast

Peter C Morris

Xavier Gros

Antoni Gil Miquel

Javier Salvador Lagares Garcia

A system and method are provided for selectively warming a printhead in response to a relatively sudden change in one or more operating conditions of a printer. These operating conditions may include, for example, duty cycle, print density, print speed, and the like, which can be empirically detected, calculated, or predicted. Because sudden changes in printing conditions generally do not occur frequently, the printhead will not be warmed at all for much of its operating time. This reduces dramatic fluctuations in drop volume, to prevent thermal banding, while not maintaining the printhead at an undesirably high temperature.

Selectively warming a printhead for optimized performance

Techniques for pausing and resuming printing operations in mid-plot while reducing visible artifacts. A pause row/swath location is determined at which printing is to be paused. In one pause/resume mode, printing of all rows and all pixels from commencement of printing through the row location is completed, and no pixels in rows immediately following the row location are printed. The printing is paused for a time interval, and operations such as a pen refill can be performed. Printing is resumed at a resume row location immediately following the pause row location to print only rows following the pause row, wherein wet ink is not applied to locations printed prior to the pausing. In another pause/resume mode, in a multi-pass print of an image, the pause occurs upon completion of a pass without completing all printing prior to the pause row. Following the pause interval, printing is resumed, as though a pause had not occurred. The pause/resume mode is selected in dependence on print parameters, including media type and print quality.

Mid plot refill technique for large scale printers

A variable maximum operating temperature for a printhead is defined and utilized within both a system and a method. The variable maximum operating temperature varies according to one or more operating conditions within a printer into which the printhead may be installed. If a detected temperature of the printhead is greater than the variable maximum operating temperature for a detected operating condition, the printer will be shut down to prevent overheating. Accordingly, the system and method extend the useful life of the printhead and reduce paper waste.

Variable maximum operating temperature for a printhead

In various methods, image registration variations among test patterns are used to calibrate misalignment among one or more printheads, paper advance distance, different portions of an inkjet printhead, or bidirectional printhead alignment. A set of test patterns are printed. Each pattern includes a reference portion and a varying portion. The varying portion is changed from pattern to pattern in a manner for testing a parameter being calibrated. An optical sensor scans each test pattern. The parameter setting for the lest pattern having the highest reflectance (i.e., most blank space) is selected as the calibrated parameter value.

Inkjet printhead calibration

In accordance with the invention a set of dyes suitable for use in ink-jet inks and method for formulating the same are provided. A specific dye set for formulating the yellow, cyan, magenta, and optionally black inks is disclosed, comprising Direct Yellow 132, Direct Blue 199, Magenta 377, and optionally Pacified Reactive Black 31 dyes, respectively. This dye set provides ink-jet prints able to match printed color standards such as specification for web offset publications (SWOP) and Euroweb, with excellent lightfade and pen reliability performance.

Dye set for improved ink-jet print quality

Ink jet ink compositions containing an aqueous carrier medium, an aqueous carrier medium insoluble colorant, a structured polymeric dispersant and a film-forming polyacrylamide polymer having a weight average molecular weight of 500-100,000 exhibit reduced film cracking, rapid drying, excellent image definition, are storage stable and have excellent decap properties and, when used in combination with a differently colored ink, result in reduced bleed in multi-colored printed elements.

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Barcelona, Spain

David H Donovan