Partitioned array ejection chips for micro-fluid applications

#The present invention relates to micro-fluid ejection devices, such as inkjet printers. More particularly, although not exclusively, it relates to ejection heads having multiple ejection chips adjacently joined to create a lengthy micro-fluid ejection array or print swath. Ejection chips with chevron shapes facilitate certain designs. Partitioning ink arrays leads to still other designs.

#The art of printing images with micro-fluid technology is relatively well known. A permanent or semi-permanent ejection head has access to a local or remote supply of fluid. The fluid ejects from an ejection zone to a print media in a pattern of pixels corresponding to images being printed. Over time, the fluid drops ejected from heads have become increasingly smaller to increase print resolution. Multiple ejection chips joined together are also known to make lengthy arrays, such as in page-wide printheads.

#In lengthy arrays, fluid ejections near boundaries of adjacent chips have been known to cause problems of image “stitching.” Registration needs to occur between fluid drops from adjacent firing elements, but getting them stitched together is difficult especially when the firing elements reside on different substrates. Also, stitching challenges increase as arrays grow into page-wide dimensions, or larger, since print quality improves as the print zone narrows in width. Some prior art designs with narrow print zones have introduced firing elements for colors shifted laterally by one fluid via to align lengthwise with a different color near terminal ends of their respective chips. This, however, complicates chip fabrication. In other designs, complex chip shapes have been observed. This too complicates fabrication.

#The accompanying drawings incorporated in and forming a part of the specification, illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:

#FIG. 1 is a diagrammatic view in accordance with the teachings of the present invention of a micro-fluid ejection head having multiple ejection chips having skewed nozzle arrays;

#FIG. 2 is a diagrammatic view in accordance with the teachings of the present invention showing improved imaging resolutions;

#In the following detailed description, reference is made to the accompanying drawings where like numerals represent like details. The embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized and that process, electrical, and mechanical changes, etc., may be made without departing from the scope of the invention. Also, the term wafer or substrate includes any base semiconductor structure, such as silicon-on-sapphire (SOS) technology, silicon-on-insulator (SOI) technology, thin film transistor (TFT) technology, doped and undoped semiconductors, epitaxial layers of silicon supported by a base semiconductor structure, as well as other semiconductor structures hereafter devised or already known in the art. The following detailed description, therefore, is not to be taken in a limiting sense and the scope of the invention is defined only by the appended claims and their equivalents. In accordance with the present invention, methods and apparatus include ejection chips for a micro-fluid ejection head, such as an inkjet printhead.

#With reference to FIG. 1, plural ejection chips n, n+1, . . . are configured adjacently in the direction (A) across a media to-be-imaged. The micro-fluid array 10 includes as few as two chips, but as many as necessary to form a complete array. The array typifies variability in length, but two inches or more are common distances depending upon application. Arrays of 8.5″ or more are contemplated for imaging page-wide media in a single printing pass. The arrays can be used in micro-fluid ejection devices, e.g., printers, having either stationary or scanning ejection heads.

#Each chip includes pluralities of fluid firing elements (shown as darkened circles representing nozzles). The elements are any of a variety, but contemplate resistive heaters, piezoelectric transducers, or the like. They are formed on the chip through a series of growth, patterning, deposition, evaporation, sputtering, photolithography or other techniques. They have spacing along an ink via to eject fluid from the chip at times pursuant to commands of a printer microprocessor or other controller. The timing corresponds to a pattern of pixels of the image being printed on the media. The color of fluid corresponds to the source of ink, such as those labeled C (cyan), M (magenta), Y (yellow), K (black).