Electric heating – Metal heating – By arc
Reexamination Certificate
1999-09-30
2001-05-08
Evans, Geoffrey S. (Department: 1725)
Electric heating
Metal heating
By arc
C219S121710
Reexamination Certificate
active
06229114
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention is directed to precision cut fluid seals, such as for use in any microfluidic device including ink jet print cartridges, and methods for precision cutting such fluid seals. In particular, the present invention is directed to precision cutting methods using a laser cutting source.
2. Description of Related Art
Making a connections between two fluid containing or transporting components is widely practiced. In the new and emerging area of microfluidics, the fluid carrying components are small, in the range of 500 microns down to as small as 1 micron and possibly even smaller. For a general description of this class of devices, see for example, the conference proceedings “Microfluidic Devices and Systems,”
Proceedings of the SPIE,
Vol. 3515 (1998). Microfluidic devices pose challenges in fluid path connection both within the microscopic componentry and also for the connection between a microfluidic device and macroscopic fluid containers or transporters. Such microfluidic devices are important in a wide range of applications that include drug delivery, analytical chemistry, microchemical reactors and synthesis, genetic engineering, and marking technologies including a range of ink jet technologies including thermal ink jet.
In existing thermal ink jet printing, such as disclosed in U.S. Pat. No. 4,774,530, the print cartridge comprises one or more ink filled channels, communicating with a relatively small ink supply chamber or manifold, at one end and having an opening at the opposite end, referred to as a nozzle. A thermal energy generator, usually a resistor, is located in each of the channels, a predetermined distance from the nozzles. The resistors are individually addressed with a current pulse to momentarily vaporize the ink and form a bubble, which expels an ink droplet. As the bubble grows, the ink bulges from the nozzle and is contained by the surface tension of the ink as a meniscus. As the bubble begins to collapse, the ink still in the channel between the nozzle and resistor starts to move towards the collapsing bubble, causing a volumetric contraction of the ink at the nozzle and resulting in the separation of the bulging ink as a droplet. The acceleration of the ink out of the nozzle while the bubble is growing provides the momentum and velocity of the droplet in a substantially straight-line direction towards a recording medium, such as paper. Because the droplet of ink is emitted only when the resistor is actuated, this general type of thermal ink jet printing is known as “drop-on-demand” printing.
U.S. Pat. No. 5,736,998 describes an improved ink seal between a nozzle plate and the pen cartridge in an ink jet printhead. Though mention is made of optimized shape and the use of a dispensed bead of adhesive, no mention is made of a laser cut seal or a discreet fluid seal member.
Another exemplary print cartridge is disclosed in U.S. Pat. No. 4,463,359. The disclosed print cartridge has one or more ink-filled channels, which are replenished by capillary action. A meniscus is formed at each nozzle to prevent ink from weeping therefrom. A resistor or heater is located in each channel upstream from the nozzles. Current pulses representative of data signals are applied to the resistors to momentarily vaporize the ink in contact therewith and form a bubble for each current pulse. Ink droplets are expelled from each nozzle by the growth and collapse of the bubbles. The current pulses to the heater are shaped to prevent the meniscus from breaking up and receding too far into the channels after each droplet is expelled. In addition, various embodiments of linear arrays of thermal ink jet devices are known, such as those having staggered linear arrays attached to the top and bottom of a heat sinking substrate and those having different colored inks for multiple colored printing.
Previously, a typical end-user product in this art was a cartridge in the form of a prepackaged, usually disposable, item comprising a sealed container holding a supply of ink and, operatively attached thereto, a die module having a linear or matrix array of channels. Presently, however, products are designed using a more permanent (or at least multi-use) print cartridge connected to a replaceable ink tank unit. Generally, the cartridge or print cartridge unit may include terminals to interface with the electronic control of the printer; electronic parts in the cartridge itself are associated with the ink channels in the print cartridge, such as the resistors, as well as digital means for converting incoming signals for imagewise operation of the heaters. In one common design of printer, the cartridge is held with the print cartridge in close proximity to the sheet on which an image is to be rendered, and is then moved across the sheet periodically, in swaths, to form the image, much like a typewriter. Full-width linear arrays, in which the sheet is moved past a linear array of channels that extends across the full width of the sheet, are also known. Typically, cartridges are purchased as needed by the consumer and used either until the supply of ink is exhausted, or, equally if not more importantly, until the amount of ink in the cartridge becomes insufficient to maintain the back pressure of ink to the print cartridge within the useful range.
However, in many of the various print cartridge designs, an important feature of the print cartridge is the fluid seal, generally located between the ink supply manifold and the ink drop ejecting die module. The fluid seal is important because it must ensure a tight seal between the ink manifold and the die module. If a tight seal is not maintained, then ink can leak out of the print cartridge through the connection area and/or air and other contaminants can be introduced into the print cartridge and ink supply. A second important function is to seal the ink manifold fluid path in areas adjacent to the die module.
One example of a fluid seal is disclosed in U.S. Pat. No. 5,696,546, which describes an ink cartridge for an ink jet printer, having an ink supply in a housing in fluid communication with an ink supply manifold. The ink is contained in an absorbent material in the ink supply, which has a housing floor having a vent and an ink outlet into a manifold. The manifold is an elongated recess in the outer surface of the housing. There can be a single or multiple chambers connected to a single or multiple ink supplies, depending on whether the print cartridge is a monochrome or multicolor print cartridge. The chamber or chambers in the manifold have a common flat surface. A fluid seal or film member is bonded to this flat surface by an adhesive not attacked or eroded by the ink. This bond between the fluid seal and manifold must prevent ink from leaking from the manifold or ink leaking between chambers within the manifold. There is at least one via or opening that goes all of the way through the fluid seal for each chamber in the manifold. These vias provide fluid communication between each manifold chamber and an inlet of the die module. The surface of the film member opposite the surface bonded to the manifold is coated with a thermosetting adhesive, which bonds to a die module surface containing the ink inlets. The die module ink inlet is of similar size and is aligned with the vias in the fluid seal. The adhesive makes a seal around the via in the fluid seal and the inlet to the die module to provide a fluid communication path between a chamber of the manifold and the inlet to the die module while preventing fluid from leaking out of the desired fluid path. The adhesive bonding the fluid seal to the housing floor is either a pressure sensitive adhesive or the same thermosetting adhesive as is used on the other side of the film member. In this reference, the fluid seal is cut using a die cutting method.
As generally practiced in the art, fluid seals and other parts are cut from multilayer sheet stock using a die cutting process. For an application such as the creation of fluid seals,
Andrews John R.
Hawkins William G.
Hilton Brian S.
Moore Steven R.
Prince C. Glenn
Evans Geoffrey S.
Oliff & Berridg,e PLC
Xerox Corporation
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