Incremental printing of symbolic information – Ink jet – Ejector mechanism
Reexamination Certificate
2000-06-09
2001-07-17
Berman, Susan W. (Department: 1711)
Incremental printing of symbolic information
Ink jet
Ejector mechanism
C347S020000, C347S045000, C430S270100, C430S280100, C522S100000, C522S111000, C522S142000, C522S143000, C522S079000, C522S146000, C525S391000, C525S392000, C525S396000, C525S401000, C525S471000
Reexamination Certificate
active
06260949
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to curable compositions having improved characteristics. The present invention is also directed to improved photoresist compositions and to improved thermal ink jet printheads. One embodiment of the present invention is directed to a composition comprising a blend of (a) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (b) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator. Another embodiment of the present invention is directed to a process which comprises the steps of (a) providing a composition comprising (i) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (ii) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator; (b) exposing the composition to actinic radiation, thereby causing the photoreactive epoxy resin to become crosslinked or chain extended; and (c) subsequent to step (b), heating the composition to a temperature sufficient to cause crosslinking or chain extension of the thermally reactive polymer. Yet another embodiment of the present invention is directed to a photoexposed and thermally cured composition comprising a substantially homogeneous blend of at least one crosslinked or chain extended thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof and at least one crosslinked or chain extended photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator. Still another embodiment of the present invention is directed to an ink jet printhead which comprises (i) an upper substrate, and (ii) a lower substrate in which one surface thereof has an array of heating elements and addressing electrodes formed thereon, said lower substrate having an insulative layer deposited on the surface thereof and over the heating elements and addressing electrodes and patterned to form recesses therethrough to expose the heating elements and terminal ends of the addressing electrodes, said upper and lower substrates being bonded together to form a thermal ink jet printhead having droplet emitting nozzles defined by the upper substrate, the insulative layer on the lower substrate, and the heating elements in the lower substrate, wherein at least one of said upper substrate and said insulative layer comprises a material formed by crosslinking or chain extending a composition comprising a blend of (a) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (b) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator. Another embodiment of the present invention is directed to a process for forming an ink jet printhead which comprises: (a) providing a lower substrate in which one surface thereof has an array of heating elements and addressing electrodes having terminal ends formed thereon; (b) depositing onto the surface of the lower substrate having the heating elements and addressing electrodes thereon a layer comprising a photopatternable polymer; (c) exposing the layer to actinic radiation in an imagewise pattern such that the photopatternable polymer in exposed areas becomes crosslinked or chain extended and the photopatternable polymer in unexposed areas does not become crosslinked or chain extended, wherein the unexposed areas correspond to areas of the lower substrate having thereon the heating elements and the terminal ends of the addressing electrodes; (d) removing the photopatternable polymer from the unexposed areas, thereby forming recesses in the layer, said recesses exposing the heating elements and the terminal ends of the addressing electrodes; (e) providing an upper substrate comprising a supporting substrate and, coated thereon, a material formed by crosslinking or chain extending a composition comprising a blend of (i) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (ii) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator, and (f) bonding the upper substrate to the lower substrate to form a thermal ink jet printhead having droplet emitting nozzles defined by the upper substrate, the photopatternable polymer on the lower substrate, and the heating elements in the lower substrate. Yet another embodiment of the present invention is directed to a process which comprises the steps of: (a) depositing a layer comprising a composition comprising a blend of (i) a thermally reactive polymer selected from the group consisting of resoles, novolacs, thermally reactive polyarylene ethers, and mixtures thereof; and (ii) a photoreactive epoxy resin that is photoreactive in the absence of a photocationic initiator onto a lower substrate in which one surface thereof has an array of heating elements and addressing electrodes having terminal ends formed thereon, said polymer being deposited onto the surface having the heating elements and addressing electrodes thereon; (b) exposing the layer to actinic radiation in an imagewise pattern such that the photoreactive epoxy resin in the layer in exposed areas becomes crosslinked or chain extended and the photoreactive epoxy resin in the layer in unexposed areas does not become crosslinked or chain extended, wherein the unexposed areas correspond to areas of the lower substrate having thereon the heating elements and the terminal ends of the addressing electrodes; (c) removing the composition from the unexposed areas, thereby forming recesses in the layer, said recesses exposing the heating elements and the terminal ends of the addressing electrodes; (d) subsequent to step (c), heating the layer to a temperature sufficient to cause crosslinking or chain extension of the thermally reactive polymer of the layer composition; (e) providing an upper substrate; and (f) bonding the upper substrate to the lower substrate to form a thermal ink jet printhead having droplet emitting nozzles defined by the upper substrate, the photoexposed and thermally cured polymer blend composition on the lower substrate, and the heating elements in the lower substrate.
In microelectronics applications, there is a great need for low dielectric constant, high glass transition temperature, thermally stable, photopatternable materials for use as interlayer dielectric layers and as passivation layers which protect microelectronic circuitry. Poly(imides) are widely used to satisfy these needs; these materials, however, have disadvantageous characteristics such as relatively high water sorption and hydrolytic instability. There is thus a need for high performance materials which can be effectively photopatterned and developed at high resolution.
One particular application for such materials is the fabrication of ink jet printheads. Ink jet printing systems generally are of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field which adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium.
Since drop-on-demand systems require no ink recovery, charging, or deflection, the system is much
Luca David J.
McGrane Kathleen M.
Smith Thomas W.
Berman Susan W.
Byorick Judith L.
Xerox Corporation
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