Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
1998-07-13
2001-11-06
Barlow, Jr., John E. (Department: 2853)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S067000, C347S045000, C427S240000
Reexamination Certificate
active
06312085
ABSTRACT:
The present invention concerns inkjet print heads which consist, at least in part, of a polymer material which is produced with the use of silicon-organic compounds with polycondensable and polymerizable groups.
At the present time, inkjet print heads must be manufactured in ever increasing numbers. On the one hand, this printing technique has, in the meantime, found enormous application and, secondly, it is desirable to develop an inexpensive print head, which can, each time, be exchanged together with the ink cartridge.
Ink jet print heads consist—in addition to the actor, i.e. (heating element, piezo element, electro-dynamic converter etc.)—of structures for fluid transport (channel walls, channel coverings, jet walls, jet coverings, ink supply) ink filters and a non-wetting jet exit side (for example jet plate). Modern inkjet print head have in common planar construction, which facilitates by means of semiconductor production, a relatively cost-effective, highly accurate manufacture in large quantities. There are differences in construction: in the so-called “edge-shooter arrangement” the droplet expulsion occurs tangentially vis-a-vis the heating element surface, while in the so-called “side-shooter arrangement” the droplet is emitted normally relative to the heating element surface.
The layered construction of the “edge shooter variation” (substrate, thin film structure, channel structure, channel covering, glass tub with ink reservoir) requires jets which are formed by different materials with varying wetting properties (thin-film layer, photoresists channel wall, photoresists adhesive layer, channel covering). These varying wetting properties have a negative effect upon the droplet formation. Therefore, with “edge shooter arrangements” there exists the additional requirement of coating the jet exit surface with a hydrophobe material.
In contrast, the jet exit of the side shooter arrangement jet plate consists of only one material. Consequently, identical wetting properties exist in the jet area. An additional coating (“Antitriel”-coating) is needed only if the hydrophobic properties of the material are insufficient.
Normally, the channel structures of present-day print head are produced from photoresists on acrylate basis by means of photolithographic processes. Forturan glass is employed, for example, which is structurally corrodible following mask exposure.
It is the object of the present invention to make available a universally employable material for inkjet print heads with which it is possible to completely produce channel structures, substrates, jet plates, jets, ink reservoirs, ink filters and similar for color and single color inkjet print heads, and whose hydrophobe properties suffice in order to forego the application of an “Anti-Wetting”-Coating. The material shall be cost-effective and structuring shall be effected with little expenditure and/or high precision.
Said object is solved by providing a polymer material for inkjet print heads which is basically produced from, or with utilization of, at least one compound I
X
a
R
b
SiR
1
(4−a−b)
I
with
X
=
hydrolyzable group
R
=
if required, substituted alkyl, aryl, alkenyl,
alkylaryl or arylalkyl,
R′
=
organic remainder with at least one
polymerizable Group
a
=
1 to 3
b
=
0 to 2.
It could hereby be discovered that the manufacture of channel structures can be effected with the aid of technically or physically different processes, so that depending upon the individual requirements as to quality and price, particularly cost-effective heads can be produced as so-called “disposable” heads, while with a somewhat more costly process print heads of particularly high quality can be produced, which provide longer service life or are suitable for greater ink through-put.
Polymer materials of the type employed according to the invention are part of the material category of the so-called ORMOCERS (ORganically MOdified CERamics). They may be classified among the inorganic and organic polymers. Production takes place based on alkoxides of silicon and, if needed, supplementary to other metals which have been modified, totally or partially, by organically polymerizable substituents. By means of hydrolysis and condensation, the inorganic part of the network is formed by means of polymerization, polyaddition or other organic coupling reactions, the organic part from reactive organic substituents.
By targeted incorporation of photo-interlinkable organic groups and components, it is possible to produce the aforementioned ORMOCERS for photolitographical and other relevant applications. Preferably, 4-component systems are involved, which can be specifically modified and adapted to the specification profile for micro-electronic, micro-optical and micro-mechanical requirements.
Layers which are to be structured can be produced as follows according to the invention: To begin with, within a polycondensation reaction (for example in the Sol-Gel Process) a pre-condensate (mostly called “lacquer” in this text) is produced from the chosen educts, which depending upon the employed chemical compounds, usually has a storage stability of several months. The lacquer can be varied in its solid matter contents, for example by draining of solvents or water or also by addition of another solvent. The lacquer is subsequently applied to the desired substrate material in form of a layer by immersion, hurling or spraying, whereby the substrate may not only consist of foreign material such as glass, ceramic, metal or extraneous polymer, but also of the identical material. By exposure of structure (mostly UV light) the lacquer can be photopolymerized with any chosen technology at the desired locations, whereby, by means of a so-called “developmental step” the non-exposed part is leached out (negative-resist-behavior), which can be done with the aid of solvents such as acetone or alkaline watery medium. In conclusion, the already structured material is completely interlaced. Mechanical pressing is also possible with simultaneous or subsequent exposure and succeeding thermal post-interlacing.
Thus, is preferred that the polymer material contain both photopolymerizable groups as well as thermally interlinkable groups. In addition, of course, a photoinitiator and, if needed, an accelerator, for example, an amine base, is added.
An example of the development of a polymer “ORMOCER”-Hybrid material is shown in FIG.
1
.
To begin with, by polycondensation of alkoxysilanes, the inorganic oxide network is first constructed—in a subsequent step, the mathacryl groups of the 3-methacryloxyproplytrimethoxysilane (MEMO) are photo-chemically interlaced and finally the epoxy groups of 3-Glycidoxypropyltrimethoxysilane (GLYMO) are thermally polymerized, so that an organic network is created.
The following systems are proving themselves as particularly suitable for the manufacture of the polymer material.
GMP2T, GMDT, GMP2D and GMD, with
G
=
Glycidoxypropyltrimethoxysilane,
P2
=
Diphenylsilandiol
M
=
Methacryloxypropyltrimethoxysilane,
T
=
Tetraethoxysilane and
D
=
Dimethyldimethoxysilane.
Suitable photochemical radical starters are for example Quantacure ITX by Shell Chemie, Irgacure 184 by Ciba-Geigy or Darocur 4263 by Messrs. Merck. Suitable as accelerator for the photo-chemical interlacing is, for example N-Methyidiethanolamine or Diethylenetriamine, whereby the latter can as well function as epoxide hardener.
Mixtures of these can also be employed.
Employment of the GMP2T System is particularly preferred.
The lacquer is preferably produced in that the desired silanes are, if needed, mixed with additional additives (for example network builders or modifying substances) and, if necessary, hydrolyzed under heat, by adding water. Addition of water may be done slowly, so that the system is initially supplied with sub-stoichiometric amounts.
The liquid lacquer, manufactured as described above, is brought, if needed, to a desired solid matter contents, which is preferably done b
Buhler Karl
Kappel J{overscore (u)}rgen
Martin Adelheid
Olsowski Birke-E.
Popall Michael
Barlow Jr. John E.
Fay Sharpe Fagan Minnich & McKee LLP
Pelikan Produktions AG
Shah M S
LandOfFree
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