Ink slots for providing ink to unilateral heaters

Details Ink slots for providing ink to unilateral heaters Ink slots for providing ink to unilateral heaters

2002-05-13

2004-12-28

Stephens, Juanita (Department: 2853)

Incremental printing of symbolic information

Ink jet

Ejector mechanism

C347S094000

Reexamination Certificate

active

06834944

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a thermal inkjet print head and, more particularly, to a thermal inkjet print head chip with at least two ink slots disposed outside two columns of heaters in which each ink slot provides ink to unilateral heaters.
2. Description of the Related Art
Thermal inkjet print heads, successively commercialized on the inkjet printer market, are operated by rapidly heating a small volume of ink, vaporizing the ink, then bubbling and ejected it through nozzle orifice by high pressure. Thus, a dot of ink can be printed onto a recording medium, such as a sheet of paper. Generally, for a one-color inkjet head chip, a single strip of ink slots is used to provide ink to two columns of firing chambers through ink channels, respectively. Also, a thin film heater is disposed inside each firing chamber to cause ink to vaporize and be ejected through one correspondingly positioned nozzle orifice.
FIG. 1A
is a top view showing a conventional one-color inkjet head chip.
FIG. 1B
is a top view partially enlarging the firing chamber and ink slot shown in
FIG. 1A. A
one-color inkjet head chip
10
comprises two columns of firing chambers
12
in which the firing chambers
12
arranged in one column are not aligned, and a common ink slot
14
disposed between the two columns of firing chambers
12
. Also, a plurality of ink channels
18
is provided to the firing chambers
12
respectively for connecting the firing chambers
12
and the ink slot
14
. Furthermore, each firing chamber
12
comprises a nozzle orifice and a heater
16
disposed under the nozzle orifice. Therefore, an ink flow
20
moves from the ink slot
14
toward the bilateral firing chambers
12
, and then the heater
16
vaporizes the ink to eject an ink dot from the nozzle orifice. Moreover, for providing a power source to the chip
10
, a plurality of connecting wires
22
is patterned on the chip
10
to electrically connect the heaters
16
and a plurality of contact pads
24
, respectively.
Conventionally, shaping techniques, such as etching, laser working and sandblasting are selected to form the ink slot
14
. However, since the lateral space of the ink slot
14
is limited to the two columns of the firing chambers
12
, the error tolerance when forming the ink slot
14
is very small, and the lateral size of the ink slot
14
cannot be further increased. This decreases the ink flow amount, speed, supply, and print quality. In addition, the connecting wire
22
is a single metal layer. When the resistance compensation is processed to give each heater
16
an equivalent wiring resistance, the line width of the metal layer is in need of modulation. Nevertheless, depending on the arranged density of the connecting wires
22
, the line width of the metal layer is limited.
FIG. 2
is a top view showing a conventional multi-color inkjet head chip. A conventional multi-color inkjet head chip
26
can provide at least three colors of ink from different ink reservoirs. For example, the chip
26
comprises a first inkjet system A, a second inkjet system B and a third inkjet system C. Each of the inkjet systems A, B or C has two columns of firing chambers
12
A,
12
B or
12
C, a common ink slot
14
A,
14
B and
14
C, and a plurality of connecting wires
22
A,
22
B or
22
C for electrically connecting the heaters to the contact pad
24
. The firing chambers, ink slots and connecting wires within the inkjet systems A, B and C are similar to the description in FIG.
1
B. Since the ink slot
14
A provides ink to bilateral firing chambers
12
A, the above-described problems in the one-color inkjet head chip
10
are also encountered in the multi-color inkjet head chip
20
.
SUMMARY OF THE INVENTION
The present invention is an inkjet print head chip with at least two ink slots outside two columns of firing chambers. Each ink slot provides ink to unilateral heaters in one column of firing chambers.
In one preferred embodiment, An inkjet print head chip comprises: a first column of firing chambers and a second column of firing chambers in which each firing chamber comprises a heater and an ink channel; a first ink slot formed between the first column of firing chambers and the periphery of the chip to provide ink to the heaters in the first column of firing chambers; and a second ink slot formed between the second column of firing chambers and the periphery of the chip to provide ink to the heaters in the second column of firing chambers.
In another preferred embodiment, an inkjet print head chip comprises: a first column of firing chambers and a second column of firing chambers in which each firing chamber comprises a heater and an ink channel; a plurality of first ink sub-slots formed between the first column of firing chambers and the periphery of the chip to provide ink to the heaters in the first column of firing chambers; a plurality of second ink sub-slots formed between the second column of firing chambers and the periphery of the chip to provide ink to the heaters in the second column of firing chambers; and a dry film patterned on the chip to separate the first ink sub-slots and the second ink sub-slots.
In another preferred embodiment, an inkjet print head chip comprises: a first column of firing chambers and a second column of firing chambers in which each firing chamber comprises a heater and an ink channel; a first ink slot formed between the first column of firing chambers and the second column of firing chambers to provide ink to heaters in the first column of firing chambers; a second ink slot formed between the second column of firing chambers and the periphery of the chip, in which the second ink slot comprises a plurality of second ink sub-slots and each second ink sub-slot provides ink to part of heaters in the second column of firing chambers; and a dry film patterned on the entire surface of the chip to separate the second ink sub-slots.
In another embodiment, an inkjet print head chip further comprises: a plurality of connecting wires in which each connecting wire comprises at least two metal layers and an isolating layer; and a plurality of ladder-shaped connecting vias formed between the metal layers and the isolating layer.
The connecting wire goes around the region between the first column of firing chambers and the second column of firing chambers to couple to the periphery of the chip.
Accordingly, it is a principal object of the invention to improve inkflow amount, speed, supply, and print quality.
It is another object of the invention to increase the error tolerance when forming the ink slot.
Yet another object of the invention is to reduce the total area occupied by the connecting wires to compensate for the size of the ink slots.
Also, when the resistance compensation is processed to make each heater
36
have an equivalent wiring resistance, one method is to increase the line width of the metal layer and the other method is to increase the thickness of the metal layer. It is more flexible to adjust the sheet resistance of the connecting wire
42
.
It is a further object of the invention to process the resistance compensation by increasing the line width of the metal layer or increasing the thickness of the metal layer.
These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings.


REFERENCES:
patent: 4905017 (1990-02-01), Sugitani et al.
patent: 6267468 (2001-07-01), Torgerson et al.

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