Metal working – Piezoelectric device making
Reexamination Certificate
1999-09-14
2002-10-22
Vo, Peter (Department: 3729)
Metal working
Piezoelectric device making
C029S890100, C029S830000, C347S071000, C347S072000, C264S642000, C156S089110, C156S252000
Reexamination Certificate
active
06467137
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
The present invention claims priority from Japanese Patent Application No. 10-263415 filed Sep. 17, 1998, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is utilized in a printer for a computer, a facsimile or a copier, etc. The present invention relates to an improvement of a structure of an ink jet recording head to be used in an ink jet recorder and a manufacturing method thereof. Particularly, the present invention relates to an improvement of an ink jet recording head having pressure chambers each having a wall surface made of ceramics, for selectively pressurizing ink therein to jet ink droplets through nozzles of the head.
2. Description of Related Art
An ink jet recording head comprises a plurality (n) of nozzles, n discrete pressure chambers provided correspondingly to the respective n nozzles, an actuator for selectively producing mechanical displacement in the discrete pressure chambers and an ink pool for supplying ink to the discrete pressure chambers. The number n of the nozzles may be, for example, 24 or 48. The actuator is driven such that an internal pressure of each discrete pressure chamber corresponding to a nozzle from which ink is to be jetted is pulsated. The n nozzles are usually arranged with an interval of from several millimeters to ten and several millimeters and the ink jet recording head is compact. Therefore, the ink jet recording head must be realized by precise machining.
One example of a conventional ink jet recording head having such structure is disclosed in Japanese Patent Application Laid-open No. Hei 8-58089, in which wall surface portions of discrete pressure chambers are formed of ceramics. With the use of ceramics as the wall surface material of the discrete pressure chambers, an anti-corrosive, ink jet recording head can be realized. Therefore, the life of the ink jet recording head can be elongated. Further, since ceramics material has high rigidity, it is possible to reduce mechanical displacement of a wall surface of each discrete pressure chamber by internal pressure of the discrete pressure chamber, compared with a case where a similar wall structure is realized by adhering plastic material and metal material together. This structure is superior in that an amount of ink to be jetted from a nozzle can be made uniform and that unnecessary pressure propagation (cross-talk) to adjacent discrete pressure chambers is small.
The present inventors had investigated the above mentioned conventional structure disclosed in Japanese Patent Application Laid-open No. Hei 8-58089 and have found that it is impossible to check an interior of each discrete pressure chamber of the disclosed structure during a manufacturing process since sintering of ceramics is performed in a state where the discrete pressure chambers are substantially sealed. That is, when the ceramics sintering process is performed while the discrete pressure chambers are substantially sealed, there may be a case where extraneous substances resulting from such as partial falling of ceramics material are left as they are in the discrete pressure chambers.
Further, there may be a case where a volume of each discrete pressure chamber is occasionally becomes larger or smaller than a standard volume. Since such defect, if any, is found by an operation test of a finished ink jet recording head, the manufacturing yield is degraded, causing the cost of product to be increased.
In the structure in which the discrete pressure chambers are substantially sealed, it is impossible to easily perform a hydrophilic processing and other processing for inner wall surfaces of the discrete pressure chambers. Therefore, it is difficult to obtain a required operation performance of the ink jet recording head and the life of the ink jet recording head is shortened.
SUMMARY OF THE INVENTION
The present invention was made in view of the above mentioned difficulty and has an object to provide a structure of an ink jet recording head in which surface portions of walls of an ink pool and discrete pressure chambers can be formed of ceramics to provide superior anti-corrosive characteristics against ink and reduced mechanical displacement of the discrete pressure chambers and interiors of the discrete pressure chambers and the ink pool can be checked during a manufacturing steps and the manufacturing method thereof.
Another object of the invention is to reduce a product cost by improving yield thereof.
Another object of the present invention is to provide a structure of an ink jet recording head having discrete pressure chambers can be performed for interiors of the discrete pressure chambers thereof and a manufacturing method thereof.
A further object of the present invention is to provide a structure of an ink jet recording head in which cross-talk between adjacent discrete pressure chambers is reduced and in which density of discrete pressure chambers can be increased, size can be reduced and nozzles can be increased in number, and a manufacturing method thereof.
In order to achieve the above objects, the manufacturing method of the present invention is featured by that the durability and reliability of an ink jet recording head formed of ceramics are improved and the printing quality is improved. In the present invention, the sintering step is performed while the discrete pressure chambers and the ink pool are open and the discrete pressure chambers are sealed by adhering a vibration plate to the pressure chamber plate after a check step.
That is, a first feature of the present invention is a first method for manufacturing an ink jet recording head having discrete pressure chambers each having a ceramics wall surface, comprising the steps of laminating, on one and the other surfaces of an ink supply plate formed with a plurality of discrete ink supply ports and the corresponding number of nozzle ports, a green sheet for a pressure chamber plate and a green sheet for an ink pool plate, respectively, sintering a lamination resulting from the laminating step and adhering a vibration plate to said pressure chamber plate sintered in the sintering step and a nozzle plate to said sintered pool plate.
The ink supply plate may be made of metal. Alternatively, the ink supply plate may be of ceramics. In the latter case, it may be a green sheet in this stage or a ceramics plate provided by preliminarily sintering the green sheet. The first method may further comprises, between the sintering step and the adhering step, the step of checking wall surfaces of the discrete pressure chambers or the step of performing a hydrophilic processing with respect to the ceramics wall surfaces of the discrete pressure chambers. That is, the discrete pressure chambers after the sintering step are in open state, so that interiors of the discrete pressure chambers can be checked by a microscope, etc., to exclude the ink supply plate having defect, if any. Further, it is possible to perform the ceramics wall surface processing.
It is preferable that the green sheet for the pressure chamber plate is formed with holes corresponding to the discrete pressure chambers before the laminating step and the green sheet for the ink pool plate is formed with a hole corresponding to the ink pool before the laminating step.
In the first manufacturing method, the ink supply plate is prepared first and then a plurality of discrete ink supply ports and the same number of discrete nozzle ports communicated with respective nozzles are formed in the ink supply plate. Thereafter, a green sheet for the discrete pressure chamber plate and a green sheet for the ink pool plate are prepared, holes corresponding to the discrete pressure chambers are formed in the green sheet for the pressure chamber plate and a hole corresponding to the ink pool and holes corresponding to the discrete nozzle ports are formed in the green sheet for the ink pool plate.
The green sheets for the pressure chamber plate having the holes corresponding to the di
Ikuina Kazuhiro
Kanda Torahiko
Kondo Takaharu
Notsu Katsuhiro
Otsuka Yasuhiro
Dickstein , Shapiro, Morin & Oshinsky, LLP
Tugbang A. Dexter
Vo Peter
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