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CLAIM OF PRIORITY
[0001]This patent application claims priority from U.S. Provisional Patent Application No. 60/961,779 filed on Jul. 24, 2007, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002]The present invention relates to an ink cartridge and an ink cartridge holder. More particularly, the present invention relates to the ink cartridge for supplying ink to a recording apparatus.
[0003]Generally, an ink jet recording apparatus is designed to print data by causing the recording head to move back and forth along the width of a recording sheet. Ink is supplied from an ink supply source to the recording head. As a result, the ink jet recording apparatus that must produce a large number of copies must carry a larger-sized ink cartridge which cannot be mounted on a carriage. Thus, the ink cartridge is mounted on the housing of the recording apparatus, and the ink may be supplied to the recording head through a tube.
[0004]An ink jet recording apparatus can be provided which includes an ink cartridge holder on which an ink cartridge filled with ink is detachably mounted. A large-size ink cartridge is used for the ink jet recording apparatus which records on large-size papers, such as posters or the like, in order to cope with a large quantity of ink consumption.
[0005]The ink cartridge used for the ink jet recording apparatus may be provided with a memory device or chip which stores information, such as a type of ink, color of ink, remaining amount of ink and the like. An information reading section is provided on the ink cartridge holder at a position facing the chip when the ink cartridge is mounted on the ink cartridge holder, and the chip on the ink cartridge and the information reading section on the ink cartridge holder are electrically connected and communicate with each other.
[0006]Existing wide format ink cartridges often have a bag or collapsible ink reservoir contained within a rigid housing. An example of such a cartridge is shown in U.S. Pat. No. 6,053,606. A problem with this arrangement is that as the bag collapses, pockets of ink become trapped in the bag, thus reducing the efficiency of the cartridge. Also, air bubbles may form in the ink supply port, and become trapped as well, which may result in imaging defects at the printer.
[0007]The printer is designed to allow the customer to remove the cartridge to swap out different colors within the same port. Every time the cartridge is re-inserted into the printer, air is injected into the cartridge and positioned within the same compartment where the ink needle will be. This will provide the opportunity for air to be suctioned into the printer's ink line and create imaging defects such as missing jets or the entire color to deprime. Each cartridge insert adds significantly more air into the cartridge, thus, drastically accelerating printing failure. As the ink is consumed from printing, it can be expected that the customer will swap different colors based on the design of the printer. If the cartridge is laid on its side where the ink inlet is at the elevated position, air will enter into the ink fluid channel due to density of the two fluids. Upon re-inserting this cartridge back into the printer's port, the air due to buoyancy will float into the horizontal chambers where the printer's ink needle is located.
[0008]Trapped air bubbles in the ink fluid path are suctioned into the printer's ink. This trapped air results in missing jets or depriming of the entire color in the printing images.
[0009]There are at least four ways for bubbles to be formed in compartments of the ink fluid flow path of the cartridge. A first way is during ink filling of the cartridge, which may leave initial air bubbles in the fluid path section. If the cartridge is vacuum filled, air will be left behind in the cartridge after filling the cartridge. The air enters into the ink fluid flow path of the cartridge by orientating the air bubbles at the inlet. A second way that air bubbles are formed is during packaging and shipment of the cartridge. A third way is if the cartridge is laid flat on the table, air bubbles will wick into the fluid passage and float forward and possibly deprime the cartridge.
[0010]Fourth, as the cartridge is inserted into the printer, the design of the septum or valve in the ink supply port will trap free air as the ink travels from the cartridge to the printer. The rubber septum has a cylindrical cavity but seals to the outer diameter of the printer's ink needle by a compression fit. The nose of the printer's ink needle is typically a tapered cylinder which traps the air in the cylindrical volume of the rubber septum. This trapped air is squeezed into the ink cartridge's fluid compartment(s).
[0011]Thus, there is a need for a geometry of the ink fluid flow path which would overcome the foregoing difficulties while providing better and more advantageous overall results.
SUMMARY OF THE INVENTION
[0012]The present invention relates to an ink cartridge. More particularly, it relates to a wide format ink cartridge for use with an ink cartridge holder. The wide format cartridge contains ink in a box-like cavity. Air will reside in the box for such reasons as volumetric expansion of the ink, such as the ink expanding during freeze testing to survive shipping. Also, air may be entrained into the fluid channel where the air can be suctioned into the ink needle of the printer.
[0013]The existing fluidic geometry of ink cartridges results in a bubble positioned in a first compartment of the ink supply flow path exhibiting a drag force; and, thus, a negative pressure gradient results, pulling the bubble(s) into the ink. With an improved fluid flow geometry, there is no significant drag force on the simulated bubble, and there is no significant pressure gradient formed around the bubble.
[0014]In the improved compartment geometry air trapped upon insertion into the printer will enter a second, additional compartment. Air bubbles will float to the top of the new reservoir or compartment.
[0015]The improved flow path geometry results in no significant flow around a bubble positioned close to the flow path. The improved geometry results in virtually no pressure gradient surrounding the bubble. An inlet filter and wicks in the first compartment significantly reduce air ingestion without affecting image quality.
[0016]First and second compartments are combined into one bubble trap reservoir where the bubbles will float away from the ink needle. The second compartment may also have a sloped upper wall or ceiling. The slope of the ceiling must have enough slope to allow the bubbles to slide and not stick to the surrounding surfaces. The internal surfaces are preferably smooth, not rough, which will help in minimizing the amount of slope surface in order to have enough room for the valve design space.
[0017]In accordance with one aspect of the invention, an ink cartridge has a plurality of walls forming an internal cavity which is substantially filled with ink and an ink supply flow path is provided in one of the walls of the ink cartridge. An ink supply port is provided in another of the walls of the cartridge, wherein the ink supply flow path connects to the ink supply port. The ink supply flow path includes a first compartment and a second compartment, wherein the first compartment houses a wicking member, and the second compartment is configured to trap air bubbles in ink as it travels through the ink supply flow path.
[0018]One aspect of the present invention is the provision of providing two chambers in an ink supply flow path of an ink cartridge to trap bubbles formed in the ink.
[0019]Another aspect of the present invention is the provision of a reservoir formed in the second compartment which is longer and larger than the first compartment to trap bubbles and prevent the bubbles from traveling through the ink flow path in an ink supply path for preventing bubbles from forming in the ink.
[0020]Another aspect of the present invention is the provision of an ink cartridge which has a second compartment with a sloped surface for preventing bubbles from sticking to a surface of the compartment.
[0021]Other aspects of the invention will become apparent upon a reading and understanding of the following detail description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022]The foregoing advantages of the present invention, and others, will in part be obvious and in part pointed out more fully hereinafter in conjunction with the written description of the embodiments illustrated in the accompanying drawings in which:
[0023]FIG. 1 is a perspective view of a front side of an ink cartridge in accordance with a first embodiment of the present invention;
[0024]FIG. 2 is a partial elevational view of a side wall of the ink cartridge of FIG. 1;
[0025]FIG. 3 is a front elevational view of a front wall of the cartridge of FIG. 1;
[0026]FIG. 4 is a perspective view of the rear side of the cartridge of FIG. 1;
[0027]FIG. 5 is a perspective view of an ink cartridge holder which receives the ink cartridge of FIG. 1;
[0028]FIG. 6 is a top plan view of an ink cartridge being inserted into the ink cartridge holder of FIG. 5;
[0029]FIG. 7 is a top plan view of the ink cartridge of FIG. 1 with the cover removed;
[0030]FIG. 8 is a perspective view of the ink cartridge of FIG. 1 showing the cover installed;
[0031]FIG. 9 is a top plan view of the ink cartridge showing the internal cavity with an ink supply flow path with a compartment for trapping bubbles in accordance with an embodiment of the present invention;
[0032]FIG. 10 is a top plan view of the ink cartridge showing the ink supply fluid path with a compartment for trapping bubbles with a sloped surface in accordance with another embodiment of the present invention;
[0033]FIG. 11 is an enlarged view of the ink supply flow path of FIG. 10; and
[0034]FIG. 12 is a plan view of the two compartments of FIG. 11.
DETAILED DESCRIPTION OF THE INVENTION
[0035]Referring now in greater detail to the drawings, wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and not for the purpose of limiting the invention, FIG. 1 is a front perspective view of the ink cartridge according to the first embodiment of the present invention An ink cartridge 10 according to the first embodiment includes an ink cartridge main body 12 having a substantially rectangular parallel piped shape, an information storing unit 14 provided on a recess 16 which is adjacent a first side or a first wall 18 of the ink cartridge main body, and an ink supply unit 20 provided on a front surface 22 of wall 18. The body is formed by side walls 18, 24, 26, 28 and wall 30.
[0036]The ink cartridge main body includes a cavity 32 with one side being open, an ink supply port 34 (FIG. 3) provided at end 18 and is fixed to end 18, and a substantially flat cover plate 36 (FIG. 4). In this ink cartridge main body, the internal cavity 32 of the cartridge is substantially filled up with ink. The internal cavity 32 is formed by walls 18, 24, 26, 28, and 30 of the main body. An ink supply flow path 38 (FIG. 7) such as a channel for facilitating flow of ink from the main body to the ink supply port is provided in a recess 41 (FIG. 2) of wall 30. The channel 38 has a first, straight portion 31 extending along a first axis 33 of the body and a curved portion 35 connecting a second straight portion 37 extending perpendicular to first portion 31 and along second axis 39 of the body. The cover is fixed to the side walls 18, 24, 26, 28 of the container main body, such as by vibration, welding, or the like, with the internal cavity 32 of the container being enclosed by the cover. Thereby, a large quantity of ink is held and the large quantity of the ink is supplied to the ink jet recording apparatus stably which records on large-size papers such as posters or the like.
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