Patent Application
20060165935
Imaging devices may include an imaging fluid storage container for supplying ink to a printhead for printing an image on a media. The imaging fluid storage container may include a gas vent to maintain a pressure within the storage container during printing. A mechanical seal may be utilized to seal the gas vent of the imaging device such that imaging fluid may not easily flow through the gas vent during altitude changes, such as during air transport, of the imaging device. The mechanical seal may include vacuum packaging of the entire imaging fluid storage container. The mechanical seal is manually removed by the operator upon first use of the imaging device. It may be desirable to eliminate the time and expense of the mechanical seal thereby reducing packaging costs and set-up time of the imaging device.
Lid 14 may further include three gas vents 24 that may each define an elongate labyrinth that begins at a gas vent entrance 34 in communication with an interior of container 16, winds along a small-cross sectional area gas vent labyrinth path 36, and which terminates in a gas vent exit aperture 38 that is in communication with the ambient atmosphere. Gas vent exit aperture 38 may be positioned within a window 40 of selectively permeable membrane 12.
Gas exiting container 16 is forced to travel through gas vent entrance 34, along winding labyrinth path 36, and out to the atmosphere through gas vent exit aperture 38. The long exit path 36 facilitates condensation of the gas exiting container 16 such that fluid is hindered from exiting gas vent exit aperture 38. The addition of selectively permeable membrane 12 to lid 14 further enhances the fluid flow inhibiting characteristics of gas vent 24. The size of window 40 may be based on the cross-sectional surface area of aperture 38, the type of fluid 18 contained with container 16, the porosity of membrane 12 (discussed in more detail below), the type of transport that imaging device 18 may be subjected to, or any other variables that may be applicable.
First layer 44 may be an adhesive layer including three sub-layers 44a, 44b and 44c. First and third sub-layers 44a and 44c may be an acrylic, such as an acrylic pressure sensitive adhesive. Second sub-layer 44b may be a tissue layer also known as a carrier, such as Polypropylene. In this embodiment three layers are utilized so that the tissue or carrier layer could be chosen to further minimize the Water Gas Transmission Rate of membrane 12, or a material could be chosen to minimize the Oxygen Transmission Rate if required. Alternatively, layer 44 could be simplified by using a monolayer of adhesive.
Second layer 46 may be a selectively permeable layer, such as a hydrophobic layer or an oleophobic layer and, in particular, may be a layer of polytetrafluoreneethylene (PTFE). Second layer 46 may provide a positive vent gas exchange rate in a range of 0.5 to 1.5 cubic centimeters per minute. Second layer 46 may selectively allow gas to vent therethrough but may hinder imaging fluid 18 from flowing therethrough. Second layer 46 may retain its selective permeability characteristics up to 14,000 feet in elevation, such as during periods of transport of imaging device 18 by air. Second layer 46 may define a porosity range of 0.45 to 1.00 microns so that membrane 12 may be referred to as selectively porous. Second layer 46 may inhibit a flow therethrough of fluids with a surface tension in a range of 20 to 70 Dynes/Cm. These properties allow membrane 12 to selectively inhibit or regulate the flow of fluid therethrough, such that imaging fluid 18 may not seep or flow through gas vent 24, even during periods of high stress, such as during impact, vibration or altitude changes during transport. Moreover, due to the controlled venting of container 16 through membrane 12, more ink than heretofore placed in container 16 may be initially placed within container 16, thereby increasing the imaging run time of imaging device 10 before imaging fluid 18 is depleted. Selectively permeable membrane 12, therefore, including selectively permeable layer 46, may allow gas 52 to vent out of container 16 through membrane 12 at window 40, may allow gas 54 to vent into container 16 through membrane 12 at window 40, and may inhibit imaging fluid 18 from exiting container 16 through membrane 12 at window 40.
Third layer 48 may be an adhesive, such as acrylic used to bond the second layer 46 to the fourth 50.
Fourth layer 50 may be a material such as Oriented Polypropylene and may include an exposed surface 50a that is oxidized by a corona discharge process to provide a printable surface. The corona discharge may oxidize exposed surface 50a by the formation of polar groups on reactive sites, thereby making surface 50a receptive to coatings thereon, such as printing. Accordingly, exposed surface 50a of fourth layer 50 may define a printable surface that may allow marketing, labeling, barcode information or the like to be printed thereon. Additionally, layer 50 may define a water gas transmission rate (WVTR) of 0.1 to 0.14 g/100 sq. in/day@100 Degrees F., 90% RH (wherein this measured value is based on the water gas transmission rate through a sheet of the material without the other layers of the stack being present, i.e., measured when this layer stands alone).
Other variations and modifications of the concepts described herein may be utilized and fall within the scope of the claims below.
