Hewlett-packard Company

Jeffrey P Baker

Duong T La

Randy Allen Coverstone

A method for improving the print quality of ink used in ink-jet printers, particularly thermal ink-jet printers, is provided. For an ink typically comprising about 90 to 98 wt % water and about 10 to 2 wt % diethylene glycol plus about 0.1 to 12 wt % dye, the improvement is achieved by adding an additive consisting essentially of about 1 to 30 wt % ethanol, about 1 to 30 wt % n-propanol, about 1 to 10 wt % iso-propanol, or about 0.002 to 0.05 wt % of 2,5,8,11-tetramethyl-6-dodecyn-5,8-diol.

Additive to aqueous-based inks to improve print quality

A disposable thin film resistor type thermal ink jet pen including a housing having a support surface at one end thereof with openings for passing ink to an adjacent thin film resistor type thermal ink jet printhead. The printhead is mounted on the support surface and has ink ejection orifii therein communicating with openings in the support surface. A porous foam material is mounted within the housing and is operative to receive and retain a supply of ink for feeding the ink by capillary action through the openings in the support surface and to the ink jet printhead. The foam ink storage material is compressed in one or more compartments of the housing to reduce the pore size therein and reduce the foam thickness while increasing its density. By this process, the capillary force of the foam is increased and thereby renders this ink storage medium especially well-suited for feeding ink on demand to a thin film resistor type of thermal ink jet printhead.

Thin film resistor type thermal ink pen using a form storage ink supply

The novel pen body construction described herein includes multiple ink storage compartments communicating with a multi-orifice printhead, and these compartments are adapted to receive sections of ink-storage foam. Preferably, this foam is a reticulated polyurethane foam of controlled porosity and capalarity and is especially well suited for storing different ink colors, such as cyan, magenta and yellow. However, single compartment black ink storage is also within the scope of this invention.

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San Diego, CA, United States of America

Jeffrey P Baker