1. Field of the Invention
The invention relates to an inkjet printing head for performing the ejection of ink on a print medium as drops, and a method of manufacturing an inkjet printing head. The invention may be applied to a general printing device, and in addition the invention may be applied to a copier, a fax machine having a communications system, a word processing device, etc., having a print section, and an industrial use printing apparatus in which various processing devices are combined together.
2. Description of the Related Art
In inkjet printers of recent years, high speed printing has become possible due to an increase in refill frequency in the liquid ejection heads, due to technological advances. In carrying out printing, time-division driving is routinely performed as it is necessary to restrain voltage drop due to the increase of current momentarily flowing to heaters and electrodes, and to provide a high duty image at a high quality. When high speed printing and time-division driving are combined, however, when printing ruled lines, etc., a negative effect often occurs wherein it is not possible to form straight lines, etc.
It is necessary to implement an ejection scheme in order to bring these techniques together. With respect to such problems, Japanese Patent Laid-Open No. 2001-347663 proposes a means of correcting landing position by way of shifting the positional relationship between the heating elements and ejection ports. More specifically, it describes preserving image linearity even in the case of performing time-division driving by way of arranging either of the heating elements or the ejection ports in an approximately straight line and relatively shifting the positions of the heating elements and the ejection ports.
It is also described therein that if with respect to all nozzles the heating elements and the space at the bifurcated position from the ink supply port to the ink flow paths are made as close as possible to within manufacturing tolerances it is possible to raise refill frequency to its maximum and improve printer throughput.
With the method of resolution set forth in Japanese Patent Laid-Open No. 2001-347663, however, the shape of the heating elements is changed, and in the case of a higher aspect ratio or a lower ejection amount, bending of liquid drops decreases and it becomes difficult to achieve the expected landing position correction. In short, the design range of the shape of the heating elements or the ejection amounts, etc., in which the effect is exhibited, is limited, and there was a possibility that the degree of design freedom was narrowed.