Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-03-07
2001-01-23
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S068000, C347S069000, C347S071000, C347S072000
Reexamination Certificate
active
06176571
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a processing device, for example, a printer device applied with advantage to an on-demand type ‘ink jet printer’ device (referred to hereinafter simply as an ‘ink jet printer’ device).
BACKGROUND OF THE INVENTION
Heretofore, this sport of the ‘ink jet printer’ device is such a printer device in which ink drops are emitted responsive to a recording signal for printing a picture on a recording medium, such as paper of film. Recently, this sort of the printer device is finding extensive application because it can realize a small size and a low cost.
In this ‘ink jet printer’ device, two methods, for example, are used for emitting ink drops, namely a method of employing heating elements and a method of using piezoelectric devices, such as piezo devices.
With the method of employing the heating elements, ink drops are emitted via an emission nozzle under the pressure of bubbles generated on heating the ink to ebullition by the heating elements.
With the method of using the piezoelectric devices, the piezoelectric devices are deformed for pressurizing a pressure chamber charged with the ink for emitting the ink liquid drops via a nozzle port communicating with the pressurizing chamber and via an emission nozzle.
Among the methods of using the piezoelectric devices, there are a method of linearly displacing a layered type piezoelectric device comprised of three or more piezoelectric portions bonded to a vibrating plate for pressurizing the pressure chamber via the vibrating plate and a method of applying a voltage across single-layer or two-layer piezoelectric portions bonded to a vibrating plate for pressurizing the pressure chamber via the vibrating plate.
FIG. 119
shows an illustrative structure of a printer head in this sort of the ‘ink jet printer’ device. This printer head
10200
includes a first solution supply duct
10202
formed for opening on a surface
10201
a
of a base block
10201
and flown through by an ink supplied from an ink tank, not shown, a pressurizing chamber
10203
formed for opening on the surface
10201
a
of the base block
10201
in communication with the first solution supply duct
10202
and a second solution supply duct
10204
formed on the opposite side with respect to the first solution supply duct
10202
on both sides of the pressurizing chamber
10203
towards the surface
10201
a
of the base block
10201
.
The base block
10201
is formed with a nozzle inlet port
10205
for opening on an opposite side surface
10201
b
of the base block
10201
in communication with the second solution supply duct
10204
. On the surface
10201
a
of the base block
10201
is bonded a vibration plate
10206
via an adhesive, not shown. The vibration plate
10206
covers the ports in the pressurizing chamber
10203
and the first and second solution supply ducts
10202
,
10204
. To the vibration plate
10206
is mounted an ink supply pipe, not shown, connected to the ink tank. To this end, the vibration plate
10206
is formed with a through-hole, not shown, conforming to the ink supply pipe.
On a surface
10206
a
of the vibration plate
10206
in register with the pressurizing chamber
10203
is bonded a single-plate type piezoelectric device
10207
by an adhesive, not shown.
On the opposite side surface
10201
b
of the base block
10201
is bonded an orifice plate
10208
by heat pressing for covering the opening area of the nozzle inlet port
10205
. In this orifice plate
10208
is bored an emission nozzle
10208
a
in communication with the nozzle inlet port
10205
.
If a pre-set pressure is applied on the piezoelectric device
10207
of the printer head
10200
, this piezoelectric device
10207
becomes contracted in the in-plane direction by the bimorph effect so as to be warped in a direction shown by arrow A in FIG.
119
. With such warping of the piezoelectric device
10207
, the vibrating plate
10207
is warped in the direction shown by arrow A in FIG.
119
. The result is that the pressurizing chamber
10203
is decreased in volume and hence increased in pressure so that the ink charged into the pressurizing chamber
10203
is discharged via emission nozzle
10208
a
through the nozzle inlet port
10205
.
In the above-described printer head, plural pressurizing chambers
10203
are arranged side-by-side. The first solution supply ducts
10202
are arrayed in parallel with the longitudinal direction of a connection pipe with an ink tank, not shown, termed an ink buffer tank
10209
. It should be noted that the first solution supply ducts
10202
are arranged in a direction perpendicular to the arraying direction of the pressurizing chambers
10203
, that is at right angles with a supply surface
10209
a
of the ink buffer tank
10209
(the connection surface of the first solution supply duct
10202
in the ink buffer tank
10209
). The ink is supplied from the ink tank via an ink supply pipe, not shown, mounted in a through-hole
10209
b
of the ink buffer tank
10209
. Thus, the ink supplied from the ink tank via the ink buffer tank
10209
is supplied to the second solution supply duct
10204
.
Recently, document preparation using a computer, termed desktop publishing, has become popular, such that a demand for outputting not only letters or figures but also a colored natural image such as a photograph along with the letters or figures is increasing. For printing the natural image of high quality, reproduction of the half the is crucial.
For representing the half tone, the voltage or the pulse width applied to the piezoelectric device or heating device is changed for controlling the emitted liquid drop size for varying the represented printing dot diameter. Alternatively, each pixel is constituted by a matrix of, for example,
4
x
4
dots, without changing the dot diameter, for representing the gradation by the so-called dither method on the matrix basis.
However, with the method of controlling the emitted liquid drop size in the printer head of the ‘ink jet printer’ device by varying the voltage or pulse width applied to the piezoelectric device or heating device, there is imposed a limitation to the minimum liquid drop size because the ink cannot be emitted if the voltage or the pulse width applied to the piezoelectric device or heating device is lowered excessively. The result is that the low concentration, in particular, cannot be represented such that the number of gradations that can be represented becomes smaller.
On the other hand, if each pixel is represented by a 4×4 matrix by the method of representing the gradation by the dither method,
17
gradations of the concentration can be represented, however, if printing is done with the same dot density as that in the above method, deterioration is lowered by one-fourth to render roughness apparent. Thus, none of the above methods is practically not sufficient to print out a natural image.
For eliminating the defect of the ‘ink jet printer’ device, there has recently been proposed a ‘carrier jet printer’. The printer head of the ‘carrier jet printer’ device gives gradation in a dot by a quantitation nozzle for quantitating an ink and emitting the resultant quantitated ink and an emission nozzle for emitting the dilution solution. The ink emitted by the quantitation nozzle and the dilution solution emitted by the emitting nozzle are unified for varying the ink concentration for giving the gradation in a dot.
This ‘carrier jet printer’ device also is in need of an ink drop emitting function similar to that required of the ‘ink jet printer’ device. As a method for emitting the drops, a method of employing a piezoelectric device or a heating device similar to that used in the ‘ink jet printer’ device is customarily used.
The printer head of the above-mentioned ‘carrier jet printer’ device is constructed as follows: On one surface of the base block, there are defined a first pressurizing chamber charged with a dilution solution, a second pressurizing chamber charged with ink and first and second liquid supply ducts for supplying the di
Kishima Koichiro
Tanikawa Toru
Barlow John
Do An H.
Sonnenschein Nath & Rosenthal
Sony Corporation
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