Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2001-07-11
2003-05-20
Vo, Anh T. N. (Department: 2861)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
Reexamination Certificate
active
06565196
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an ink jet head, a method of manufacturing the same, and an ink jet recording apparatus.
BACKGROUND OF THE INVENTION
In recent years, ink jet heads having densely arranged nozzles that are produced by using a so-called “transfer process” are known in the art, as disclosed in, for example, Japanese Laid-Open Patent Publication No. 10-286953. A transfer process is an advantageous process as a method of producing a high-density print head. In a transfer process, first, a thin film actuator is produced as follows, for example. That is, a separate electrode is formed on a substrate made of single crystal MgO, or the like, and then a perovskite-type dielectric thin film made of PZT is formed as a piezoelectric member on the separate electrode. Moreover, a vibration plate that functions also as a common electrode is formed on the piezoelectric member by a method such as sputtering. Then, the thus produced actuator is attached to a pressure chamber plate, and the whole or part of the substrate is thereafter removed.
However, it was difficult to produce a line type ink jet head with the transfer process as described above for the following reasons.
In a line type ink jet head, the length of the ink jet head in the width direction (i.e., the longitudinal direction of the ink jet head) needs to be greater than the paper width of the recording paper. For example, in order to record information on A4-size paper, the length of the ink jet head in the width direction needs to be 210 mm or more. Therefore, the length of the single crystal MgO substrate in the longitudinal direction thereof also needs to be 210 mm or more. A single crystal MgO substrate is produced from a rock lump of MgO. However, the entire rock lump cannot be used, but what can actually be used is only a portion thereof. Therefore, in order to produce a single crystal MgO substrate whose length is 210 mm or more, it is necessary to provide a lump of MgO of such a length, thereby requiring very large equipment. Even if such a single crystal MgO substrate can be produced, it will be a very costly material because of a poor yield.
Moreover, in a transfer process, it is necessary to deposit, by sputtering, or the like, a piezoelectric element (e.g., PZT, etc.) on a substrate made of single crystal Mgo, or the like. However, it requires very large equipment to deposit PZT over a large area. In addition, the yield lowers when one attempts to obtain a piezoelectric element film that is uniform in properties such as the piezoelectric property and the thickness and that has no crack therein. Therefore, the manufacturing cost becomes very high.
For the reasons as described above, it was difficult to use a transfer process for a conventional line type ink jet head in view of the quality and the cost.
An object of the present invention is to provide a high-density print head and a recording apparatus incorporating the same, with various advantages, including an improved uniformity of the thin film actuator in terms of properties such as the piezoelectric property and the thickness, prevention of a crack occurring in the film, improvement in the manufacturing yield, downsizing of the manufacturing equipment, a cost reduction, etc.
SUMMARY OF THE INVENTION
In the present invention, a plurality of actuator blocks including piezoelectric elements, etc., are provided for each pressure chamber plate, with the size of each actuator block being reduced.
A first ink jet head of the present invention is an ink jet head including: a plurality of actuator blocks each having at least a plurality of piezoelectric elements, and a first electrode and a second electrode for applying a voltage across each of the piezoelectric elements; and a pressure chamber block having therein a plurality of pressure chambers each containing an ink, the actuator blocks and the pressure chamber block being layered on each other, wherein: an area of a layering surface of each of the actuator blocks is smaller than an area of a layering surface of the pressure chamber block; and the plurality of actuator blocks are arranged on one surface of the pressure chamber block.
A second ink jet head is the first ink jet head, wherein the pressure chamber block includes: a pressure chamber plate having therein the plurality of pressure chambers each containing an ink; a channel plate having therein a plurality of ink channels respectively communicated to the pressure chambers and a common liquid chamber communicated to the pressure chambers; and a nozzle plate having therein a plurality of nozzles respectively communicated to the ink channels, the pressure chamber plate, the channel plate and the nozzle plate being layered on one another.
A third ink jet head is the first ink jet head, wherein the plurality of actuator blocks are arranged so that edge surfaces of ones of the actuator blocks adjacent to each other in a direction perpendicular to a scanning direction are not in contact with each other.
A fourth ink jet head is the first ink jet head, wherein the plurality of actuator blocks are arranged so as to be separated from one another so that adjacent ones of the actuator blocks partially overlap with each other with respect to a direction perpendicular to a scanning direction.
A fifth ink jet head is the first ink jet head, wherein the plurality of actuator blocks are arranged so that adjacent ones of the actuator blocks are spaced apart from each other in a scanning direction.
A sixth ink jet head is the first ink jet head, wherein the plurality of actuator blocks are arranged in a staggered pattern.
A seventh ink jet head is the first ink jet head, wherein the actuator blocks include, instead of the second electrode, a conductive vibration plate functioning also as the second electrode.
An eighth ink jet head is the second ink jet head, wherein: the nozzle plate is made of a single plate; and one or both of the pressure chamber plate and the channel plate includes alignment means for aligning the nozzle plate when the nozzle plate is layered on the channel plate.
Note that the alignment means includes various means such as, for example, an alignment hole or an optically-detected alignment marker.
A ninth ink jet head is the second ink jet head, wherein: the nozzle plate is made of a plurality of plates; and one or both of the pressure chamber plate and the channel plate includes alignment means for aligning the nozzle plates when the nozzle plates are layered on the channel plate.
A tenth ink jet head is the second ink jet head, wherein the ink jet head is obtained by producing an actuator block by sequentially layering at least the first electrode, the piezoelectric element, and the second electrode, on a substrate having a smaller area than that of the pressure chamber plate, and then transferring the actuator block onto the pressure chamber plate so that the plurality of pressure chambers provided in the pressure chamber plate are covered by the second electrode.
An eleventh ink jet head is the tenth ink jet head, wherein the substrate is an MgO single crystal substrate, and the piezoelectric element is produced by sputtering.
A twelfth ink jet head is the tenth ink jet head, wherein the substrate is an MgO single crystal substrate.
A thirteenth ink jet head is the tenth ink jet head, wherein the piezoelectric element is produced by sputtering.
A fourteenth ink jet head is the second ink jet head, wherein the ink jet head is obtained by producing an actuator block by sequentially layering at least the first electrode, the piezoelectric element, the second electrode, and a vibration plate, on a substrate having a smaller area than that of the pressure chamber plate, and then transferring the actuator block onto the pressure chamber plate so that the plurality of pressure chambers provided in the pressure chamber plate are covered by the vibration plate.
A fifteenth ink jet head is the fourteenth ink jet head, wherein the substrate is an MgO single crystal substrate, and the piezoelectric element is produced by sput
Ikeda Koji
Matsuo Hiroyuki
Sogami Atsushi
Tatekawa Masaichiro
Harness Dickey & Pierce PLC
Vo Anh T. N.
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