Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-11-22
2003-02-25
Oen, William (Department: 2855)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S070000
Reexamination Certificate
active
06523942
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention generally relates to print heads for printers, and more particularly to a head (or an inkjet head) for use with an inkjet printer. The inkjet head of the present invention is applicable not only to a single printer unit but also widely to copiers, facsimile machines, computer systems word processors, and combination machines thereof which have a printing function.
Among inkjet heads, those which employ a piezoelectric element have increasingly come into the limelight in recent years due to their excellence in energy efficiency. This type of inkjet head typically includes a piezoelectric element, one common ink chamber which receives from an external device and stores ink, a plurality of pressure chambers coupled to the piezoelectric element, and a nozzle plate so connected to the pressure chambers that a nozzle may be connected to each pressure chamber. Each pressure chamber is connected to the common ink chamber through an ink supply channel so that it may receive ink from the common ink chamber and increase its internal pressure using deformation of the piezoelectric elements, thereby jetting ink from each nozzle.
In recent years, piezoelectric elements have often been manufactured by printing or sputtering of LSI technology. The LSI technology facilitates miniature piezoelectric elements, while the miniature ink supply channels are needed as well. A higher resolution is also needed by reducing an interval between two nozzles of adjacent pressure chambers (i.e., nozzle pitch) and increasing the number of nozzles. The miniature ink supply channels are also required for this purpose. The miniature ink supply channels are thus sought for both manufacturing and higher-resolution purposes.
According to ink's hydraulic resistance equivalence, a doubled number of ink supply channels would make the length of the ink supply channel twice as long as that of one ink supply channel. A quadrupled number of ink supply channels would make the length of the ink supply channel four times as long as that of one ink supply channel. Thus, in terms of hydrodynamics, ink's hydraulic resistance equivalence is maintained by increasing the length of the ink supply channel by the number of ink supply channels.
On the other hand, an ink supply channel has been demanded which is longer than a distance between adjacent pressure chambers since a long ink supply channel would enhance rigidity and strength of a wall between the common ink chamber and each pressure chamber. Some head configurations are required to be a adhered to a thin film before being adhered to a piezoelectric element in a pressure-chamber plate that includes pressure chambers, ink supply channels and a common ink chamber. Such a head calls for a longer ink supply channel so that the thin film can be firmly adhered to a larger area between each pressure chamber and the common ink chamber.
For these requirements, each pressure chamber has been allocated a plurality of (e.g., four) ink supply channels that align with a direction in which the pressure chambers are arranged in a conventional inkjet head.
However, the instant inventors have discovered those ink supply channels, which align with a direction in which the pressure chambers are arranged as in the conventional inkjet head, would prevent a higher resolution. This is because a nozzle pitch that is designed to be narrow so as to attain a high integration would necessarily lead to the narrow pressure chamber width, and it would be extremely difficult to establish multiple ink supply channels in the narrow width.
BRIEF SUMMARY OF THE INVENTION
Accordingly, it is an exemplified general object of the present invention to provide a novel and useful inkjet head and its manufacturing method in which the above disadvantages are eliminated.
A more specific object of the present invention is to provide an inkjet head and its manufacturing method which may realize a high resolution, maintain at a desired strength a wall that defines an ink supply channel between a common ink chamber and each pressure chamber, and secures a sufficient adhesion area on the wall.
The present invention also has an object to provide an inkjet head and its manufacturing method which allocate a plurality of ink supply channels so as to connect each pressure chamber to the common ink chamber, and use a dry film resist for high-precision and efficient manufacturing.
To achieve the above objects, an inkjet head of the present invention comprises a pressure-chamber plate which includes a plurality of pressure chambers which store ink and a plurality of ink supply channels that supply the pressure chamber with the ink, a piezoelectric element that may pressurize the pressure chamber in the pressure-chamber plate, and a nozzle plate that includes a nozzle which jets the ink in the pressure chamber when the piezoelectric element pressurizes the pressure chamber, wherein some of the ink supply channels are connected by the plural number to each pressure chamber, and arranged in a direction perpendicular to that in which the plurality of pressure chambers are arranged. Alternatively, said ink supply channels may be connected by the plural number to each pressure chamber, and arranged two-dimensionally at random with respect to a plane parallel to a direction in which the plurality of pressure chambers are arranged.
A manufacturing method for an inkjet head which is manufactured by joining a plurality of layered members that is made of independent multiple layers, including the step of forming one of the plurality of layered members which comprises the steps of forming a layered member by laminating a dry film resist onto a substrate having a predetermined shape, exposing part of the layered member which corresponds to pressure chambers, an ink supply channel, and a common ink chamber, and developing the layered member, wherein a plurality of ink supply channels are formed and connecting each of a plurality of pressure chambers to the common ink chamber, a direction in which the plurality of pressure chambers are arranged being perpendicular to that in which the ink supply channels allocated to each of the plurality of pressure chambers are arranged.
A manufacturing method of an inkjet head of the present invention comprises the steps of forming first and second layers defining at least one of an introduction path, a pressure chamber, an ink supply channel and a common ink chamber by using a dry film resist, forming a rigid layer on either one of the first and second layers, and joining the first and second layers to each other via the rigid layer.
A printer of the present invention comprises an inkjet head, and a drive unit which drives the inkjet head, wherein the inkjet head comprises a pressure-chamber plate that includes a plurality of pressure chambers which store ink and a plurality of ink supply channels which supply the pressure chambers with the ink, a piezoelectric element that may pressurize the pressure chamber in the pressure-chamber plate, and a nozzle plate that includes a nozzle which jets the ink in the pressure chambers when the piezoelectric element pressurizes the pressure chamber, wherein part of the ink supply channels are connected to each pressure chamber, and arranged in a direction perpendicular to that in which the plural pressure chambers are arranged.
A printer and an inkjet head of the present invention include a plurality of ink supply channels that are connected to each pressure chamber and arranged in a direction perpendicular to a direction in which the pressure chambers are arranged. Therefore, where the predetermined number of ink supply channels is needed, all of them need not align with a direction in which the pressure chambers are arranged. This however intends to exclude a structure in which all of the ink supply channels align with a direction with which the pressure chambers align, and not to prohibit some of the ink supply channels from aligning with the direction with which the pressure chambers align. For example, given
Koike Shuji
Mikami Tomohisa
Sakamoto Yoshiaki
Armstrong Westerman & Hattori, LLP
Dickens Charlene
Oen William
LandOfFree
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