Capillary regulation of ink flow in multi-chambered ink cartridge for ink jet printer.

摘要

An ink tank cartridge for an inkjet printer comprises an unvented first ink chamber 512 and a second chamber 511 adjacent to and divided from said first chamber 512 by a partition wall 510, the two chambers being in fluid communication via a laterally extending aperture 519 positioned near the bottom of the said partition wall 510. The second chamber 511 contains porous capillary material 520 (e.g. foam) in contact with both the communicating aperture 519 of the partition wall and an ink delivery port 530 in a wall of the second chamber 511. An air vent 514 into the second chamber is located well away from both the delivery port 530 and the communicating aperture 519 in the partition wall. The pressure in the unvented ink chamber remains lower than that of the atmosphere, and the capillarity of the porous material is adapted to regulate an even flow of ink from the first chamber to the outlet port via the second chamber while also regulating the admission of venting air to the first chamber. To this end a number of variations are described, which include:- (a) provision of vertical grooves in the partition wall (to facilitate air admission to the first chamber). (b) variations in the geometry of the juncture between first chamber, second chamber and partition walls (to facilitate admission of ink from the first chamber to the porous material in the second chamber), (c) adjustment of the capillarity of the porous material by differential compression thereof (e.g. by ribs 516) at different locations within the second chamber (to facilitate regulation of the flow therethrough by balancing capillary attraction against the reduced pressure in the first chamber and the capillary conditions pertaining at the outlet port). Cartridges for multicolour printers may contain respective seperate chamber systems for each of a plurality of different coloured inks. A black-only ink cartridge of enlarged ink capacity may contain two side-by side first chambers in communication with a single second chamber via a single combined communicating aperture. IMAGE