Incremental printing of symbolic information – Ink jet – Controller
Reexamination Certificate
2001-11-15
2004-03-09
Nguyen, Judy (Department: 2853)
Incremental printing of symbolic information
Ink jet
Controller
C347S059000
Reexamination Certificate
active
06702413
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid discharge head used for an ink jet recording head or the like, and a liquid discharge apparatus. The invention also relates to an IC package structure. Among them, the invention is particularly effective in the application to the so-called side shooter type liquid discharge head having substantially the perpendicular discharge direction of ink liquid droplets or the like to the assembling surface of the substrate thereof.
2. Related Background Art
In conjunction with
FIG. 12
, the description will be made of the conventional liquid discharge head, such as an ink jet recording head. The ink discharge area A of a head shown in
FIG. 12
is formed in such a way that the ink supply port
111
is provided in a silicon substrate
110
by means of chemical etching or laser or some other light energy; the electrothermal converting element
112
that serves as a discharge energy generating member is arranged on the silicon substrate
110
; the covering resin layer
120
that becomes the walls of an ink flow path
121
is provided; and the ink discharge port (orifice)
122
is formed in the covering resin layer
120
. The method of manufacture thereof is publicly known by Japanese Patent Laid-Open Application No. 06-286149 and others.
For the aforesaid side shooter type ink jet recording head, the distance between the ink discharge port
122
and the electrothermal converting element
112
, that is, an orifice distance, can be formed easily by means of a photolithographic technique. Accordingly, it is possible to manufacture an ink jet recording head that can consistently discharge small liquid droplets of ink.
The structural character of the side shooter type ink jet recording head has the following requirements:
1. The thickness thereof should be smaller in the bubble growing direction or the ink discharge direction. With a shorter distance between the covering resin layers, having the orifices formed therefor, and a recording sheet (paper), namely, the distance to the recording sheet (paper), it becomes possible to prevent the head and the recording sheet from rubbing against each other due to the deformation (cockling) of the recording sheet. The cockling results from the curling of paper by changes of environment or the swelling of fibers caused by the permeation of ink into paper. With the shorter distance between the covering resin layer and the recording sheet, it is also possible to make the deviations of target position of impact smaller so as to obtain a desired image. More specifically, the distance to a recording sheet (paper) is required to be approximately 1 mm.
2. The electrothermal converting elements should be formed in high density on the assembling surface of the substrate perpendicular to the ink discharge direction or the bubble growing direction. More specifically, it is required to provide them in a precision of 600 to 1,200 dpi or more than 1,200 dpi.
In order to attain these requirements efficiently, the head shown in
FIG. 12
is provided with a driver built-in area
123
formed on the silicon substrate
110
. The control circuit for the aforesaid electrothermal converting element
112
is incorporated here. The electrodes of a flexible printed substrate (FPC)
130
and the electrodes of the silicon substrate
110
are positioned to face each other on the assembling area B of the silicon substrate
110
, which are connected through an anisotropic conductive film or the like (not shown). The connecting portion is sealed and protected by a sealing resin
131
. In this manner, the assembling structure is adapted to connect with an external circuit (not shown).
In this case, the bubble growing direction, that is, the thickness of the ink jet recording head in the ink discharge direction, is determined by the height of assembling, that is, the thickness (approximately 25 to 150 &mgr;m) of the flexible printed substrate
130
, and the thickness of the sealing resin
131
provided for the connecting portion.
The bubble growing direction of this assembling structure, that is, the assembling surface in the direction perpendicular to the ink discharge direction, there is contained the aforesaid built-in control circuit for the electrothermal converting element
112
on the driver built-in area
123
on the silicon substrate
110
described above. The control circuit and the electrothermal converting element
112
are formed by means of photolithographic technique.
Consequently, even when the ink discharge port has a precision of 600 dpi or more, the assembling density can be made as roughly as 100 to 400 &mgr;m on the assembling area B where the source supply of electric power for the control circuit and electrodes on the input control signal side are drawn by use of the flexible printed substrate.
Next, in conjunction with
FIG. 13
, the description will be made of another conventional example disclosed in the specification of Japanese Patent Laid-Open Application No. 06-286127. Here, it is devised to make the thickness of the head smaller by externally installing an IC component (driving element)
223
for control use with inclination to the side opposite to the discharge direction of droplet ID to a recording medium P from the orifice (ink discharge port)
222
formed on the covering resin layer
221
on the substrate
210
. The assembling density of the assembling area B on the flexible printed substrate
230
is almost equal to the density of the orifice
222
and the electrothermal converting element (not shown), and the control IC component
223
is connected to the flexible printed substrate
230
by means of die-bonding wire, and then, covered by the sealing resin
231
. Consequently, to be in high density is dependent on the assembling density of the flexible printed substrate
230
. In this respect, a reference mark IT designates an ink tank.
Now, to meet the demand for enhancing the printing quality and printing speed, the side shooter type ink jet recording head is required to be elongated. However, when the driver built-in head as shown in
FIG. 12
is elongated, the following problems are encountered with respect to the assembling structure.
1. A number of substrates that can be taken from one wafer are reduced, leading to the increase in manufacturing costs. For example, in a simulation of a 4-inch recording head with the structure that has the control circuit incorporated therein, the size of the 4-inch recording head becomes approximately 8 mm×100 mm. However, only four of them can be taken from a 5-inch wafer; nine from a 6-inch wafer; and twenty-one from an 8-inch wafer.
2. The non-defective ratio becomes smaller. Assuming that the general CMOS process crystalline defect ration D≃0.003, the yield of the built-in control circuit is worked out. Then, no perfect products are obtainable from a 5- or 6-inch wafer. Also, only one perfect product is obtainable from an 8-inch wafer eventually.
For reference, the non-defective ratio is expressed by Y=exp (−S×D), S (area)=XY.
This brings about an extremely serious problem in the production when the head is elongated.
Also, for the conventional example of the ink jet recording head shown in
FIG. 13
, the assembling density on the assembling area of the flexible printed substrate
230
is substantially equal to the density of the orifice
222
and the electrothermal converting element provided for the ink discharge port area A.
However, since wiring is formed by copper foil or the like on the flexible printed substrate
230
which is formed by polyimide or the like, the limit of the precision degree is approximately 500 dpi, and there is a problem encountered that the elongation is possible only up to approximately 25 mm in terms of the practicable dimension in consideration of the stretch and contraction thereof caused by the linear expansion coefficient of polyimide and others.
SUMMARY OF THE INVENTION
It is one of the objects of the present invention to provide a liquid disch
Muta Tadayoshi
Takabayashi Hiroshi
Yamane Toru
Brooke Michael S
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Nguyen Judy
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