Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1999-01-25
2002-03-26
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S044000, C347S045000, C347S063000
Reexamination Certificate
active
06361145
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of producing an ink jet recording head, an ink jet recording head produced by the method and an ink jet recording apparatus. In particular, the present invention relates to a method of producing an ink jet recording head whose discharge port is formed by use of laser beam, an ink jet recording head produced by the method, and an ink jet recording apparatus.
2. Related Background Art
To work a discharge port (orifice) of an ink jet recording head an excimer laser beam has been recently often used. As disclosed in Japanese Patent Application Laid-Open No. 2-121843 and No. 2-187346 which corresponds to U.S. Pat. No. 5,208,604, working of an orifice by the use of excimer laser beam has been typically carried out by irradiating a discharge port forming member (orifice plate) of a top plate which integrally has a groove member in which a groove of a flow path of recording liquid (ink) was formed and a discharge port member which is positioned at the front of this groove and has a comparatively thin thickness, with excimer laser beam. Further, these Applications also disclose a method of working a taper-shaped orifice whose sectional area is gradually reduced in the discharge direction by irradiation of excimer laser from the groove side of the flow path of the top plate.
The summary of the prior art method will now be described with reference to
FIGS. 6 and 7
.
FIG. 6
is a schematic perspective view showing a conventional ink jet recording head.
FIG. 7
is a schematic cross-sectional view of FIG.
6
.
In the ink jet recording head shown in
FIG. 6
, a substrate
602
and a top plate
608
are formed while they are connected to each other. The substrate
602
is provided with an energy generator which generates energy which is utilized for discharging ink. The ink jet recording head shown in
FIG. 6
is provided with electrothermal converting elements
601
which generate thermal energy as energy generators respectively. The grooves
603
which form ink paths are formed in the top plate
608
so that they correspond to the electrothermal converting elements
601
, respectively. A discharge port forming member
605
is integrally provided on the top plate
608
at the end portion of the groove
603
so that an ink discharge port
604
is communicated with the groove
603
. To the ink flow path is supplied ink from a common ink chamber
606
defined with a frame
607
.
A top plate is provided with a groove
701
, a discharge port
702
, a discharge port forming member
703
, a common ink chamber
704
, a frame for the ink chamber and the like. The reference numeral
707
denotes excimer laser beam irradiated for working the discharge port
702
through desired optical systems. The reference numeral
708
denotes a laser beam axis of the excimer laser beam
707
. The reference numeral
709
denotes the central axis of the groove
701
. Further, the reference numeral
710
denotes a straight line l obtained by connecting the center p of gravity on plane P rectangular to the central axis
709
of the groove to the center q of gravity of the discharge port on a plane Q other than the plane P rectangular to the central axis
709
of the groove.
In such working of the discharge port by use of excimer laser beam, shown in
FIG. 7
, the straight line l
710
is not made to be parallel to the central axis
709
of the groove so that the discharge port
702
has a tapered-shape whose sectional area is reduced in the discharge direction. Further, the laser beam axis
708
becomes the same as the straight line l
710
. As the result, ink is discharged in the extended direction of the laser beam axis
708
. In this connection, a recording medium surface is shown in
FIG. 7
, for reference.
The discharge port shown in Japanese Patent Application Laid-Open No. 2-187346 has a structure which can stably obtain the amount and discharge rate of ink droplets. However, to obtain higher-definition images in the ink jet recording head, there still remains the following problems.
Namely, the discharge port
702
has the above-mentioned structure or shape, ink droplets cannot reach the recording medium surface in the vertical direction thereto. This depends on the method of working the discharge port by the use of excimer laser shown in FIG.
7
. This reason is that when the excimer laser beam
707
is radiated from a groove side of the ink flow path in the ink chamber, the excimer laser beam must be radiated at a certain angle (&thgr;
1
) so that no excimer laser beam
707
reaches the frame
705
of the ink chamber. The above-mentioned Japanese Patent Application Laid-Open No. 2-187346 discloses &thgr;
1
=10°. It is physically impossible to have condition &thgr;
1
=0° without the irradiation of the frame
705
of the ink chamber with excimer laser beam
707
. On the other hand, when the frame
705
of the ink chamber is irradiated with excimer laser beam
707
, no discharge port can be worked. A method of providing the frame
705
of an ink chamber later is considered so that the condition &thgr;
1
=0° can be obtained. However, it is actually impossible to strongly and positively adhere the frame
705
of the ink chamber, which is a minute portion, without imparting change to ink and with adhesive having resistance to ink.
Thus, there are no ways other than discharging ink droplets at the angle &thgr;
1
of the laser beam axis from the discharge port using the working method described in Japanese Patent Application Laid-Open No. 2-187346. As mentioned above, since the &thgr;
1
always has an angle larger than 0°, there are no ways other than tilting a top plate or recording medium to cause the ink droplets to reach the recording medium surface in the vertical direction thereto. Further, any method thereof has complicated and large-scale configuration, it is not always an appropriate means.
Next, the reason why obtaining high-definition images is impossible when ink droplets cannot vertically arrive at the recording medium surface, will be described.
FIG. 8
is a schematic view showing the state of arrival of the ink droplets at the recording medium surface (paper surface). In
FIG. 8
the reference numeral
801
denotes an ink droplet A discharged at a certain angle &thgr;
1
and the numeral
802
denotes an ink droplet B discharged without having a certain angle &thgr;
1
. The reference numeral
803
denotes an ideal recording medium A, and the numeral
804
denotes an actual recording medium B. The reference numeral
805
denotes the arrival position A where the ink droplet A
801
discharged at a certain angle &thgr;
1
arrives at the ideal recording medium A
803
,
806
denotes the arrival position B where the ink droplet A
801
discharged at a certain angle &thgr;
1
arrives at the actual recording medium B
804
,
807
denotes the arrival position C where the ink droplet B
802
discharged without having a certain angle &thgr;
1
arrives at the ideal recording medium A
803
, and
808
denotes the arrival position D where the ink droplet B
802
discharged without having a certain angle &thgr;
1
arrives at the actual recording medium B
804
.
The actual recording medium B
804
has a flexible shape, which is different from the ideal recording medium A
803
. When an ink droplet like the ink droplet A
801
arrives at the recording medium at a certain angle, difference occurs between the arrival position A
805
of the ink droplet and the arrival position B
806
thereof by the flexibility of the recording medium B
804
(in X direction in FIG.
8
). However, when an ink droplet like the ink droplet
802
arrives at the recording medium without having a certain angle, even though the recording medium B
804
has flexible curved surfaces, there is no difference between the ink droplet arrival position C
807
and the ink droplet arrival position D
808
. The above-mentioned points are important to attain a higher definition printing in the ink jet recording.
SUMMARY OF THE INVENTI
Abe Tsutomu
Ishimatsu Shin
Okazaki Takeshi
Omata Kouichi
Barlow John
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Shah Manish
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