Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1994-11-18
2001-02-20
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S085000
Reexamination Certificate
active
06190005
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a liquid jet recording head having a substrate provided with an ejection outlet for ejection liquid and an electrothermal transducer element for generating heat electric upon power supply to eject the liquid and a liquid jet recording apparatus having such a recording head.
Referring first to
FIG. 4
, there is shown in an exploded perspective view of a recording head of an orifice plate, partition plate and a substrate having an opening for constituting a supply port.
FIG. 5
is a persepective view of a head having a substrate provided with supply groove having a supply port at an end portion. In
FIGS. 4 and 5
, the same reference numerals are assigned to the elements having the corresponding functions.
In the recording head of
FIG. 4
, an electrothermal transducer element
12
functioning as energy applying portion is provided on a substrate
11
of silicon or the like, and at the substrate
11
, liquid supply port
13
is formed penetrating the substrate
11
. At an end of a substrate
11
, selection wiring electrode
15
and common wiring electrode
16
are formed through photolithography or the like. An ejection outlet
17
a
is disposed at a position faced to the electrothermal transducer element
12
, and the orifice plate
17
is provided with the ejection outlet
17
a.
A partition plate
18
is provided with a partition
18
a
for isolating the ejection outlets
17
a.
In the second example shown in
FIG. 4
, when the liquid supply port
13
is formed without form a hole in the substrate, a groove is formed in the substrate
11
to form a liquid supply port
13
at an end of the substrate.
With the structure of
FIG. 4
, wherein the hole is machined by ultrasonic wave machining or laser machining or the like or another method, there is a liability that the substrate is cracked when the machining is carried out. To avoid this, the machining speed can be reduced, but doing so is not satisfactory. Additionally, this method necessarily involves the reduction of productivity. The reduction in the yield and the productivity result in the cost increase.
In the case of the head having the groove as shown in
FIG. 5
, the problem of the crack is quite eased, but the problems of non-uniformity of the image density are found, when experiments are repeated with the recording head using the groove to supply the liquid. The problem particularly appears in the case of different duty pattern, line pattern, strip pattern extending in the scanning direction for checking twist. This was particularly remarkable when plural line print is effected by driving all of the ejection outlets. Then, the checking has been effected to the ejection amount of the ink for a number of ejection outlets, and it has been found that there are slight difference in the ejection amount amount between the ejection outlet near the liquid supply port and the ejection outlet remote therefrom. This would be a significant problem from the standpoint of the print quality.
After the recording head of
FIG. 5
was left in the air, the re-driving thereof is tried. There were non-ejection nozzles, for which it was confirmed that the ink exists on the electrothermal transducer and that the cause of the non-ejection was not the absence of the ink on the electrothermal transducer. The investigations were further made as to a number of non-ejection nozzles to find common problem, and it was found that the non-ejection nozzles are those disposed remote from the liquid supply port. Particularly, the remotest nozzles showed the high probability of ejection failure. The reason is considered as being the viscosity increase. So, there is a problem to be solved, which is particularly remarkable at the remote ejection outlet.
SUMMARY OF THE INVENTION
Thus, one aspect of this invention involves a method for making liquid jet recording heads, each head having a substrate with ejection energy generating elements corresponding to liquid passages and a liquid supply groove for supplying liquid to the liquid passages. This is done by preparing a base member on which the ejection energy generating elements are disposed corresponding to the substrates, forming in the base member by dicing a groove common to the plural substrates, and cutting the base member into the substrates such that each of substrates has the liquid supply groove. The liquid supply groove of each of the substrates is a portion of the common groove.
Accordingly, it is a principal object of the present invention to provide a liquid jet recording head and a liquid jet apparatus, wherein the structure of the liquid supply passage is improved to prevent the substrate crack and the variation in the ink ejection amount resulting in the non-uniform printing.
It is another object of the present invention to provide a liquid jet recording head and liquid jet apparatus wherein smooth ejection can be effected even after the recording head is left in the air.
It is a further object of the present invention to provide a liquid jet recording head and liquid jet apparatus wherein the distribution of the temperature of the substrate is improved, and the propagation of the pressure wave to the ink supply port is suppressed, thus stabilizing the ink ejections.
According to an aspect of the present invention, there is provided a liquid jet recording head comprising a substrate on which a plurality of of arrays of ejection energy generating elements for ejecting liquid; liquid passages corresponding to said ejection energy generating elements; ejection outlets for ejecting the liquid, in a direction away from the substrate, said ejection outlets being in fluid communication with said liquid passages; a cross liquid supply passage, in the form of a groove, for supplying the liquid from opposite end portions of the substrate, said cross passage being extended across said substrate.
According to another aspect of the present invention, there is provided a liquid jet apparatus comprising a liquid jet recording head including a substrate on which a plurality of of arrays of ejection energy generating elements for ejecting liquid; liquid passages corresponding to said ejection energy generating elements; ejection outlets for ejection the liquid, in a direction away from the substrate, said ejection outlets being in fluid communication with said liquid passages; a cross liquid supply passage, in the form of a groove, for supplying the liquid from opposite end portions of the substrate, said cross passage being extended across said substrate; and means for feeding a recording material on which recording is effected.
According to a further aspect of the present invention, there is provided a liquid jet apparatus comprising a liquid jet recording head including a substrate on which a plurality of of arrays of ejection energy generating elements for ejecting liquid; liquid passages corresponding to said ejection energy generating elements; ejection outlets for ejecting the liquid, in a direction away from the substrate, said ejection outlets being in fluid communication with said liquid passages; a cross liquid supply passage, in the form of a groove, for supplying the liquid from opposite end portions of the substrate, said cross passage being extended across said substrate; and means for supplying a signal for driving said recording head.
According to the present invention, the liquid supply port is formed by formation of a groove in the substrate, and therefore, the problem of the crack is solved, and the in addition, the groove extends across the substrate, so that the liquid can be supplied from the opposite end portions of the substrate by which the variation of the ejection amount can be solved, and the liquid ejection at the resuming of the drive after being left in the air. In addition, the liquid refilling performance is improved, and the ejection failure due to the non-uniformity of the temperature of the substrate.
These and other objects, features and advantages of the present invention will become more apparent
Barlow John
Brooke M.
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
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