In general, an ink jet recording head for use in an ink jet recording apparatus is composed of an ink jet recording head for forming droplets of a liquid such as ink, and of a supply system for supplying the ink and the like to the head.
With regard to a connection of a wiring board to a liquid discharge substrate, which are applied to the recording head, a wide-array ink jet apparatus composed of a printhead substrate in which an electrical connection electrode is present on a surface opposite to a surface having a discharge port therein has been disclosed in JP 11-192705A. In FIG. 18 and FIG. 19, a wide-array ink jet pen 210 disclosed in JP 11-192705A is shown. FIG. 18 is a perspective view of the wide-array ink jet pen having a wide-array printhead. FIG. 19 is a cross-sectional view of a part including a printhead die and a carrier substrate 220, showing electrical connection portions of the wide-array ink jet printhead of FIG. 18. The pen 210 is composed of a wide-array printhead 212 and a pen body 214. The pen body 214 is a housing to which the printhead 212 is attached. In the pen body 214, an internal chamber 216 serving as a local ink reservoir is present. Further, referring to FIG. 18 and FIG. 19, the printhead 212 includes plural printheads 218 attached to the carrier substrate 220. In each printhead 218, electrodes 284 for making an electrical connection and an ink supply port 242 are formed on the back surface side of a surface on which a nozzle opening 238 is formed. In the carrier substrate 220 for retaining the printhead 218, electrical wiring is installed on a first surface 270 and second surface 272 thereof, and on the first surface 270 side, the carrier substrate 220 makes the electrical connection with the printhead 218 by solder bumps, and is thus disposed. Further, a logic circuit (not shown) and a drive circuit 230 are mounted on the second surface 272 opposite to the first surface in the substrate 220.
Problems as described below are inherent in the ink jet recording head formed as described above, in which the ink supply port is formed on the back surface side of the surface of the liquid discharge substrate in which the nozzle opening is formed, the connection electrodes for making the electrical connection with the other members are provided in the vicinity of the ink supply port, and the electrical connection is made with the surface of the carrier substrate on which the electrical wiring is formed.
For example, in the ink jet recording head of FIG. 19, the ink supply ports individually formed in the carrier substrate and the liquid discharge substrate must be made to communicate with each other. Specifically, it is necessary to completely prevent the ink from entering the electrical connection portions and completely prevent the ink from leaking to the outside by forming a partition wall for surely separating a fluid on the periphery of the ink supply port.
For this purpose, dimensional and positional accuracies of the ink supply port of the liquid discharge substrate and the ink supply port of the carrier substrate become an important point.
In the head disclosed in JP 11-192705A, as shown in FIG. 19, the carrier substrate 220 is formed of a plate-like member with some thickness, which is formed of silicon, multilayer ceramics, or glass epoxy, such as one used for forming a hybrid multi-chip module.
Hence, since the head is poor in processability, the positional accuracy of the opening of the ink supply port 242 and the dimensional accuracy of the opening thereof are not very high, and accordingly, a displacement is prone to occur in a relative position thereof to the ink supply port of the liquid discharge substrate. This proves particularly troublesome in the case of using an adhesive or a sealing agent on the fluid partition wall of the ink supply port. In the case of such a construction, a position of the adhesive or the sealing agent is greatly affected by a position of an end of the ink supply port of the carrier substrate, and accordingly, when a position of an end surface of the ink supply port of the carrier substrate is overlapped with the position of the ink supply port of the liquid discharge substrate, there occurs such a problem that the adhesive or the sealing agent flows into the ink supply port of the liquid discharge substrate. Further, in the ink jet head, a necessity to array the plural liquid discharge substrates whose width is as narrow as possible at high density has increased from viewpoints of cost and size. Therefore, it is also necessary to form the ink supply ports of the liquid discharge substrate and the carrier substrate to be narrow in width and at high density. However, in the carrier substrate disclosed in FIG. 19, it is difficult to accurately form the ink supply ports narrow in width because the carrier substrate has some thickness.