BACKGROUND
It is sometimes desirable to deliver different volumes of ink in an inkjet ink pen. Inkjet ink pens are also often referred to as ink cartridges. In many conventional ink pens, a block of foam is used to hold the ink inside the pen body and help generate the backpressure needed to regulate the flow of ink to the printhead. For a particular ink pen, the foam block has a fixed size and a maximum ink capacity corresponding to the size of the foam block. The appropriate size foam block is inserted into the pen body and the desired volume of ink injected into the foam. Using conventional fill methods, ink can be accurately injected into the foam anywhere between the minimum fill volume needed to produce a working pen and the maximum capacity of the foam block. Where the desired volume of ink is well below the maximum capacity of the foam block, the foam is significantly under-filled resulting in the inefficient use of the foam. Although different sized foam blocks might be used for different ink fill volumes to more efficiently utilize the foam, each size block may require special tooling to insert the foam into the pen body. In addition, pen bodies may have to be redesigned to properly retain the different sized foam blocks. Hence, using different sized foam blocks may lead to multiple pen body designs and tooling that cannot be readily interchanged, and may still leave under-utilized foam in some pen designs.
DRAWINGS
FIG. 1 is an exploded perspective view illustrating an ink pen according to an embodiment of the disclosure
FIG. 2 is a side elevation section view of the ink pen shown in FIG. 1.
FIGS. 3A-3E are side section views of an ink pen body illustrating one embodiment of a method for filling an ink pen with a variable volume of ink in which ink soaked yarn is dispensed into the ink pen.
FIG. 4 is a flow chart illustrating the method embodiment of FIGS. 3A-3E.
FIGS. 5A-5C are plan section views illustrating example patterns for dispensing yarn into an ink pen.
FIGS. 6A-6E are side section views of an ink pen body illustrating another embodiment of a method for filling an ink pen with a variable volume of ink in which ink soaked foam pieces are dispensed into the pen.
FIG. 7 is a flow chart illustrating the method embodiment of FIGS. 6A-6E.
FIG. 8 illustrates one embodiment in which the size of the foam pieces dispensed into the pen is varied to form a higher density area and a lower density area.
DETAILED DESCRIPTION
Embodiments of the present disclosure were developed in an effort to more effectively allow for the use of different ink fill volumes in an ink pen. In the following embodiments, a first more dense material, a small foam block for example, is installed in the pen body to cover the outlet from the ink holding chamber to the printhead. Then, a second less dense material, yarn or chopped foam for example, soaked with ink is installed in the pen body until the desired volume of ink is obtained. The higher density material covering the outlet generates sufficient capillarity to wick ink to the outlet while the ink soaked fill material helps allow for more efficiently using different ink fill volumes in the ink pen. The exemplary embodiments shown and described illustrate but do not limit the disclosure. Other forms, details, and embodiments may be made and implemented. Hence, this Description should not be construed to limit the scope of the disclosure, which is defined in the claims that follow the description.
FIG. 1 is an exploded perspective view illustrating an ink pen 10 according to an embodiment of the disclosure. FIG. 2 is a side elevation section view taken along the line 2-2 of FIG. 1. Referring to FIGS. 1 and 2, ink pen 10 includes a printhead 12 located at the bottom of pen 10 below an ink holding chamber 14. Printhead 12 includes an orifice plate 16 with two arrays 18, 20 of ink ejection orifices 22. In the embodiment shown, each array 18, 20 is a single row of orifices 22. Firing resistors in a thermal inkjet printer 10, or other ink ejectors in other types of inkjet printers 10, formed on an integrated circuit chip (not shown) are positioned behind ink ejection orifices 22. A flexible circuit 24 carries electrical traces from external contact pads 26 to the ink ejectors. When ink pen 10 is installed in a printer, pen 10 is electrically connected to the printer controller through contact pads 26. In operation, the printer controller selectively energizes the ink ejectors through the signal traces in flexible circuit 24 to eject a drop of ink through an orifice 22 on to the print media.
Ink flows from ink holding chamber 14 through an outlet 28 to printhead 12. Ink chamber 14 is defined generally by a pen body 30 that includes a front wall 32, side walls 34, a back wall 36 and a floor 38. Printhead 12 is positioned below outlet 28 in a depression 40 in a front part of floor 38. Pen body 30, which is typically molded plastic, may be molded as a single unit, molded as two parts (e.g., a lid 42 and a base 44) or constructed of any number of separate parts fastened to one another in the desired configuration. A filter 46 covering outlet 28 may be used to keep contaminants, air bubbles and ink flow surges from entering printhead 12.
A small foam block 48, or other suitably more dense, absorbent ink holding material, covers outlet 28. A less dense, absorbent ink holding material 50, yarn or chopped foam for example, fills some or all of the remainder of chamber 14 to the desired volume of ink. The higher density material 48 covering outlet 28 generates sufficient capillarity to wick ink toward outlet 28 while less dense material 50 helps allow for more efficiently using different ink fill volumes in chamber 14. As ink is depleted from foam 48, the increased capillarity near outlet 28 tends to draw ink from material 50 to maximize the amount of ink drawn from chamber 14. Although a single color pen 10 with only one ink chamber 14 is shown and described, embodiments of the disclosure are also applicable to tri-color and other multi-chambered pens in which a composite ink holding material configuration may be used in one or more of the multiple ink chambers.
FIGS. 3A-3E illustrate one embodiment of a method for filling a pen 10 with a variable volume of ink. In FIG. 3A, a small foam block 48 is installed into ink chamber 14 over filter 46 and outlet 28. In FIG. 3B, ink is added to foam 48 by, for example, injecting ink into foam 48 with a needle 52. In FIG. 3C, pen 10 is primed with ink by forcing ink into printhead 12 through orifices 22. Priming ink pen 10, as used in this document, means displacing sufficient air from ink delivery areas, nozzles and/or other regions of printhead 12 such that any remaining air bubbles will not degrade print quality. FIG. 3C illustrates just one method for priming pen 10. Any suitable method for priming pen 10 may be used. For example, a low pressure may be applied to orifice plate 16 to draw ink out of foam 28 into printhead 12. In FIG. 3D, an ink absorbing yarn 50 is dispensed into ink chamber 14 from a spool 54 or other suitable dispensing unit.
One advantage of this new fill method is the ability to pre-soak the ink holding material, yarn 50 in this embodiment, with ink. Pre-soaking yarn 50 with ink helps ensure the uniform distribution of ink throughout the ink holding material in chamber 14, helps avoid undesired areas of free ink puddles in chamber 14, and helps control the volume of ink held in chamber 14. FIG. 3D illustrates generally how pre-soaked yarn 50 may be dispensed into chamber 14 from a spool 54 immersed in an ink reservoir 56 as part of a dispensing unit 58. Although it is expected that dispensing a desired length of a continuous spooled media, such as yarn 50, will be desirable in most fill methods, any suitable dispensing system may be used. Another advantage of this new fill method is the ability to vary not just the amount of ink holding material dispensed into chamber 14 but also the configuration of the ink holding material in chamber 14. For example, directional arrows 60 and 62 indicate an agitation or oscillation of pen body 30 relative to yarn 50 in dispenser 58 (or yarn 50 relative to pen body 30). By controlling the relative motion of pen body 30 and yarn 50, a variety of yarn stacking patterns can be realized in ink chamber 14. Different yarn densities and porosities, and the corresponding capillarity, may be achieved by controlling the patterns of alternate layers of yarn 50 from substantially perpendicular to substantially parallel. Finally, in FIG. 3E lid 42 is affixed to pen body 30 to complete filling pen 10.
The method embodiment described above with reference to FIGS. 3A-3E is illustrated in the flow chart of FIG. 4. Referring to FIG. 4, in an ink fill method 64, a more dense ink holding material, foam block 48 in FIGS. 3A-3E, is installed in ink chamber 14 over ink outlet 28 (block 66). Ink is injected into or otherwise added to foam 48 (block 68). Ink pen 10 is primed with ink (block 70) and a less dense ink holding material pre-soaked with ink, ink soaked yarn 54 in FIG. 3D, is dispensed into chamber 14 (block 72). As used in this document, yarn means any continuous strand of natural or man-made fibers. As noted above with regard to FIG. 3D, the act of dispensing yarn 50 into chamber 14 (block 72) may include the relative movement of pen body 30 and yarn 50 to form patterns and layers to achieve a desired density and/or porosity (and the corresponding capillarity) of yarn 50 as well as the desired ink fill volume. By determining the quantity of ink soaked yarn through the dispensing process, various ink fill levels are possible from the same yarn inventory. Although it is expected that the acts in ink fill method 64 will be performed in the order shown in FIG. 4, it may be desirable in some circumstances to deviate from the order shown. For example, automated equipment used in some conventional fill processes may be more effectively utilized in embodiments of the new fill processes by adding ink to the foam (block 68) and priming pen 10 (block 70) after dispensing yarn 50 into chamber 14 (block 72). For another example, ink may be injected into the foam (block 68) simultaneously with the priming pen 10 (block 70). Hence, the acts shown in FIG. 4 are not necessarily performed in the order shown.
FIGS. 5A-5C illustrate example patterns for dispensing yarn 50 into ink chamber 14. By changing the major direction of the yarn layers by the controlled oscillation of the pen relative to the yarn, or conversely, the oscillation of the yarn relative or the pen, various densities are achieved. In FIG. 5A, alternate yarn layers are substantially perpendicular to each other resulting in a lower density of yarn 50 in ink chamber 14. In FIG. 5B, alternate yarn layers are substantially parallel to each other resulting in a higher density of yarn 50 in chamber 14 compared with the perpendicular pattern of FIG. 5A. FIG. 5C illustrates a variable density of yarn 50 and, therefore, a corresponding variable porosity and capillarity within yarn 50. By controlling the rate of relative motion between yarn 50 and pen body 30 while the dispensing yarn 50 into chamber 14, a higher density of yarn 50 may be dispensed into one part of ink chamber 14 and a lower density of yarn 50 at another part of ink chamber 14. This density gradient creates a corresponding capillarity gradient within yarn 50 in chamber 14.
FIGS. 6A-6E illustrate another embodiment of a method for filling a pen 10 with a variable volume of ink. In FIG. 6A, a thin foam block 74 is installed into ink chamber 14 over filter 46 and outlet 28 and along the floor of chamber 14. In FIG. 6B, ink is added to foam 74 by, for example, injecting ink into foam 74 with a needle 52. In FIG. 6C, pen 10 is primed with ink by forcing ink into printhead 12 through orifices 22. FIG. 6C illustrates just one method for priming pen 10. Any suitable method for priming pen 10 may be used. In FIG. 6D, pieces of ink absorbing foam 76 is dispensed into ink chamber 14 from a hopper 78 or other suitable dispensing unit. One advantage of this new fill method embodiment is the ability to pre-soak the ink holding material, foam pieces 76 in this embodiment, with ink. Pre-soaking foam pieces 76 with ink helps ensure the uniform distribution of ink throughout the ink holding material in chamber 14, helps avoid undesired areas of free ink puddles in chamber 14, and helps control the volume of ink held in chamber 14. In this fill method embodiment, different foam densities and porosities, and the corresponding capillarity, may be achieved if desired by mixing pieces of foam with different/varying density and porosity. Finally, in FIG. 6E lid 42 is affixed to pen body 30 to complete filling pen 10.
The method embodiment described above with reference to FIGS. 6A-6E is illustrated in the flow chart of FIG. 7. Referring to FIG. 7, in an ink fill method 80, a more dense ink holding material, foam block 74 in FIGS. 6A-6E, is installed in ink chamber 14 over ink outlet 28 and covering the floor of chamber 14 (block 82). Ink is injected into or otherwise added to foam 74 (block 84). Ink pen 10 is primed with ink (block 86) and a less dense ink holding material pre-soaked with ink, ink soaked foam pieces 76 in FIG. 6D is dispensed into chamber 14 (block 88). Although it is expected that the acts in ink fill method 80 will be performed in the order shown in FIG. 7, it may be desirable in some circumstances to deviate from the order shown. For example, automated equipment used in some conventional fill processes may be more effectively utilized in embodiments of the new fill processes by adding ink to the foam (block 84) and priming pen 10 (block 86) after dispensing foam pieces 76 into chamber 14 (block 88). For another example, ink may be injected into the foam (block 84) simultaneously with priming pen 10 (block 86). Hence, the acts shown in FIG. 7 are not necessarily performed in the order shown. The desired volume of ink held in chamber 12 may be achieved by controlling the quantity of foam pieces 76 dispensed into chamber 14. Individual ink pens 10 can have custom ink fill levels determined by the quantity of foam pieces 76 dispensed into chamber 14.
FIG. 8 illustrates one embodiment in which the size of the foam pieces 76 is varied to vary the density of the ink holding material in chamber 12 and the corresponding capillarity characteristics of the ink holding material. Referring to FIG. 8, smaller pieces of foam 76a are dispensed into the bottom of ink chamber 12 to form a more dense, higher capillarity area 90, and larger pieces of foam 76b are dispensed into top of chamber 12 to form less dense, lower capillarity area 92. In one example for the ink holding material, foam pieces 76a and 76b range in size from 2 mm to 10 mm.
The present disclosure has been shown and described with reference to the foregoing exemplary embodiments. It is to be understood, however, that other forms, details and embodiments may be made without departing from the spirit and scope of the disclosure which is defined in the following claims.
Patent Application
20090071564
