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| United States Patent | 4520375 |
| Link to this page | http://www.wikipatents.com/4520375.html |
| Inventor(s) | Kroll; John W. (Greendale, WI) |
| Abstract | A fluid jet ejector, such as is used in an inkjet printer head, is provided
by a pair of spaced capacitor plates, one of which is a thin diaphragm,
preferably of semiconductor material, such as silicon. The capacitor
plates may be photolithographically developed. Impressing a time varying
voltage on the capacitor causes the diaphragm to be set into mechanical
motion. A reservoir containing fluid, such as ink, is contiguous the
diaphragm and has a nozzle through which fluid exits responsive to
diaphragm motion. |
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Title Information  |
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Drawing from US Patent 4520375 |
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Fluid jet ejector |
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| Publication Date |
May 28, 1985 |
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Title Information |
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References |
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Public's "Guesstimation" of Royalty Value
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Market Review |
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Technical Review |
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Claims |
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I claim:
1. A fluid jet ejector comprising a pair of spaced capacitor plates, one of
which is a thin diaphragm of semiconductor material, responsive to a time
varying voltage causing a varying electric field between said plates to
set said diaphragm into mechanical motion, and reservoir means containing
fluid contiguous said diaphragm and including a nozzle through which fluid
exits responsive to said diaphragm motion.
2. A fluid jet ejector comprising a pair of spaced capacitor plates, one of
which is a thin diaphragm, responsive to a time varying voltage causing a
varying electric field between said plates to set said diaphragm into
mechanical motion, and a reservoir means containing fluid contiguous said
diaphragm and including a nozzle through which fluid exits responsive to
said diaphragm motion wherein said reservoir is on the side of said
diaphragm opposite said other capacitor plate.
3. The invention according to claim 2 wherein said diaphragm is a thin
section of semiconductor material, and wherein said reservoir is formed by
side walls of said semiconductor material extending integrally from said
diaphragm.
4. The invention according to claim 3 wherein said reservoir is formed in a
semiconductor substrate by a groove or cavity etched thereinto.
5. The invention according to claim 3 comprising an end wall facing and
spaced from said diaphragm and engaging the ends of said side walls to
close said cavity, said end wall having a fluid source entry port
therethrough.
6. The invention according to claim 5 wherein said nozzle comprises a
passage along the interface of said side wall and said end wall.
7. The invention according to claim 2 wherein said voltage is varied to
drive said diaphragm with a pulsating effect to form discrete fluid drops
in the fluid stream exiting said nozzle.
8. The invention according to claim 2 wherein said voltage is varied to
drive said diaphragm at its resonant frequency.
9. An inkjet printer head comprising a pair of spaced capacitor plates, one
of which is a thin silicon diaphragm, responsive to a time varying voltage
causing a varying electric field between said plates to set said diaphragm
into mechanical motion, and reservoir means containing ink contiguous said
diaphragm and including a nozzle through which ink exits responsive to
said diaphragm motion, said reservoir being on the side of said diaphragm
opposite said other capacitor plate, said reservoir being formed in a
silicon substrate by a groove or cavity etched thereinto to provide said
reservoir between side walls of silicon extending integrally from said
diaphragm.
10. The invention according to claim 9 wherein said voltage is varied to
drive said diaphragm with a pulsating effect to form discrete ink drops in
the ink stream exiting said nozzle.
11. The invention according to claim 10 wherein said voltage is varied to
drive said diaphragm at its resonant frequency.
12. The invention according to claim 9 comprising an end wall facing and
spaced from said diaphragm and engaging the ends of said side walls to
close said cavity, said end wall having an ink source entry port
therethrough.
13. The invention according to claim 12 wherein said nozzle comprises a
passage along the interface of said side wall and said end wall. |
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Claims |
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Description |
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BACKGROUND AND SUMMARY
The invention relates to fluid jet ejectors, including the type used in
inkjet printer heads. Present inkjet printer heads employ piezoelectric
devices as the driver element. The present invention affords an
alternative to the piezoelectric element.
The present invention provides a fluid jet ejector comprising a pair of
spaced capacitor plates, one of which is a thin diaphragm, responsive to a
time varying voltage causing a varying electric field between the plates
to set the diaphragm into mechanical motion as the driver element. In the
preferred embodiment, the diaphragm is semiconductor material, such as
silicon, and the set of capacitor plates may be photolithographically
developed.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic sectional view of a fluid jet ejector constructed in
accordance with the invention.
DETAILED DESCRIPTION
FIG. 1 shows a fluid jet ejector 2, such as is used in an inkjet printer
head, comprising a pair of capacitor plates 4 and 6 spaced by insulating
means 8. Plate 6 is a thin diaphragm. The capacitor plates are responsive
to a time varying voltage from source 10 causing a varying electric field
between the plates to set diaphragm 6 into mechanical motion. A reservoir
12 contains fluid contiguous diaphragm 6, which fluid exits through nozzle
14 responsive to diaphragm motion.
In preferred form, diaphragm 6 is a thin section of semiconductor material,
such as silicon. Reservoir 12 is on the side of diaphragm 6 opposite the
other capacitor plate 4. The reservoir is formed by silicon side walls
such as 16 extending integrally from diaphragm 6. In preferred form,
capacitor plates 4 and 6 are photolithographically developed. Reservoir 12
is formed in a silicon substrate by a groove or cavity etched thereinto in
accordance with standard processing techniques. An end wall 18 is provided
facing and spaced from diaphragm 6 and engaging the ends of the side walls
to close the cavity. End wall 18 has an entry port 20 therethrough from
fluid source 22, which is an ink supply in the case of an inkjet printer
head. Nozzle 14 is a passage along the interface of side wall 16 and end
wall 18.
In the case of an inkjet printer head, voltage applied to capacitor plates
4 and 6 is varied to drive diaphragm 6 with a pulsating effect to form
discrete ink drops in the ink stream exiting nozzle 14. Though the
available driver element forces are low, the system requirements are also
low, particularly when the voltage is varied to drive the diaphragm at its
resonant frequency.
It is recognized that various modifications are possible within the scope
of the appended claims.
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Description |
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