Print array head and fabrication method thereof

Details Print array head and fabrication method thereof Print array head and fabrication method thereof

2001-10-18

2002-12-17

Nguyen, Lamson (Department: 2861)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S012000, C347S043000

Reexamination Certificate

active

06494564

ABSTRACT:

CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2000-63807, filed Oct. 28, 2000, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an inkjet print head and a fabrication method thereof, and more particularly to an array type inkjet print head in which a plurality of nozzle sections on a nozzle plate of a page width size are aligned with a plurality of heater chips, and a fabrication method thereof.
2. Description of the Related Art
Generally, an inkjet print head prints a desired image on a printing medium by instantly heating a plurality of heater chips, thus explosively vaporizing a certain amount of ink charged in ink chambers to cause ink bubbles. That is, by the expansion pressure of the ink bubbles, ink droplets are ejected out through nozzle holes to form a desired image.
As the demand for high resolution printing quality and high speed printing has increased recently, many efforts are made to develop a so-called page width array head that could print image information with a page unit by aligning the plurality of heater chips in a printing width size. Such an inkjet print array head is aimed at simplifying the design and improving the printing speed, and reference can be made to U.S. Pat. Nos. 5,469,199 and 4,851,371 for a detailed example thereof.
In the above-mentioned inkjet print array head, nozzle sections and the heater chips must be attached to each other in a highly accurate alignment. For example, in a printer having a resolution of 600 dpi (dots per inch), misalignment between the nozzle sections and the heater chips of the general inkjet print head is allowable within ±25 &mgr;m, while the misalignment in the page width array head is allowable approximately within only ±12 &mgr;m. However, due to alignment error generated during alignment of the heater chips in the general inkjet print array head, misalignment occurs in the alignment of the nozzle sections and the heater chips, and accordingly, the accuracy of the alignment is limited.
In order to secure high accuracy in the alignment of the nozzle sections and the heater chips during the fabrication process, expensive equipment such as a vision system is required, in addition to labor and other costs. Accordingly, productivity deteriorates while the fabrication costs increase. Also, due to the effect of heat during the operation of the general inkjet print array head, there is a high possibility that the alignment of the heater chips may vary, or distortion may occur due to a crack in the processing section.
Furthermore, the general inkjet print array head usually has a nozzle plate made of a polymer sheet or a metal sheet. Since the metal sheet is processed through an electro-forming process to form the nozzle holes, reproductibility deteriorates, and high accuracy is not guaranteed. Also, a distortion occurs due to a residual stress.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an inkjet print array head and a fabrication method thereof to improve productivity and printing quality by ensuring and maintaining an alignment accuracy between the nozzle sections and the heater chips.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The above and other objects are accomplished by a print array head in accordance with the present invention, including a nozzle plate of a predetermined size having a plurality of nozzle sections formed thereon in a predetermined pattern, each nozzle section comprising a plurality of nozzle holes, a plurality of heater chips aligned with the plurality of nozzle sections and attached to the nozzle plate, an ink supplying channel interconnected to each nozzle section, and a printer bar connected to the nozzle plate, facing the nozzle plate. The present print array head further includes a positioning means for aligning the plurality of heater chips with the plurality of nozzle sections.
According to the present invention, the positioning means includes an aligning hole formed at a predetermined location around each nozzle section, and an aligning mark formed at a predetermined location on each of the heater chips, coordinates of the aligning marks being aligned with coordinates of the aligning holes.
The above and other objects are also accomplished by a method to fabricate a print array head in accordance with the present invention, including forming a plurality of nozzle sections on a nozzle plate in a predetermined pattern, each nozzle section comprising a plurality of holes, forming an aligning hole at a predetermined location around each nozzle section, forming an aligning mark at a predetermined position on each of a plurality of heater chips, forming a pad-type recess on the printer bar, attaching each heater chip to the pad-type recess, and connecting the nozzle plate with the plurality of heater chips with reference to the aligning holes and the aligning marks.
According to one aspect of the present invention, the forming of the plurality of nozzle sections includes applying a photo-resist on both sides of the nozzle plate, exposing the photo-resist to a light in a predetermined pattern by using a mask, and forming a nozzle hole by etching the nozzle plate through a portion of the photo-resist that is exposed to the light and removed.


REFERENCES:
patent: 5719605 (1998-02-01), Anderson et al.
patent: 6109719 (2000-08-01), Cornell
patent: 6267472 (2001-07-01), Maher et al.

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