BRIEF DESCRIPTION OF THE DRAWINGS
In the detailed description of the preferred embodiments of the invention presented below, reference is made to the accompanying drawings, in which:
FIG. 1 is a partial schematic view of a prior art printhead assembly;
FIG. 2 is a partial schematic view of a prior art printhead assembly;
FIG. 3 is a partial schematic view of a printhead assembly including a first example embodiment of the present invention;
FIG. 4 is a partial schematic view of a printhead assembly including a second example embodiment of the present invention;
FIG. 5 is a partial schematic side view of a printhead assembly including a third example embodiment of the present invention; and
FIG. 6 is a partial schematic side view of a printhead assembly including a fourth example embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
The present description will be directed in particular to elements forming part of, or cooperating more directly with, apparatus in accordance with the present invention. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art.
Referring to FIG. 3, a drop generator 13 is operable to create liquid drops 2 in a known manner. Some of the liquid drops 2 are deflected in a known manner toward a contact region 30 of a catcher face 4. After the liquid drops 2 contact the contact region of the catcher face 4, the liquid drops 2 form a liquid film 3 that travels toward an opening or throat 5 from which the liquid is removed from the printhead assembly 34 and either recycled or disposed. A charge plate 16 including charge electrodes 7 and associated circuitry is located between the drop generator 13 and the catcher 32.
During a start up or shut down sequence, a lip portion 18 of an eyelid 15 (shown in FIG. 5) is operatively associated with the catcher 32 to form a seal with the catcher below the catch pan 6 in order to prevent liquid from contacting a recording media. After the start up sequence is complete, the lip portion 18 of eyelid 15 is positioned away from the catcher to enable liquid drops to pass between the eyelid 15 and the catcher 32 and contact the recording media.
A pair of walls 10 (only one of which is shown in FIG. 3, the second wall being essentially a mirror image of the first wall) is positioned on either side of the liquid removal opening 5 of the catcher 32. A first portion 19 of the each of the pair of walls extends in a first direction toward the fluid drop generator 13. The first portion 19 of each of the pair of walls can be substantially perpendicular to the length of the opening 5 of the catcher 32. A second portion 20 of each of the pair of walls extends in a second direction at least partially toward each other along the length of the catcher 32. The pair of walls 10 and the lip portion 18 are operable to form a fluid seal at least partially around the opening of the catcher to help prevent liquid from wicking up the catcher face. Lip portion 18 can extend beyond the pair of walls 10 (represented by reference sign 24 in FIG. 4).
The first portion 19 and the second portion 20 of the pair of walls 10 can intersect form a corner that has an angle. For example, the second portion 20 of the wall can be positioned perpendicular relative to the first portion 19 of the wall. Alternatively, the second portion 20 of the wall can be positioned at a non-perpendicular angle relative to the first portion 19 of the wall. The angle can include a radius fillet 22 as shown in FIG. 4.
Example configurations of the pair of walls 10 will be discussed next. The first portion 19 of each of the pair of walls 10 can extend to at least the liquid drop contact region 30 of the catcher 32 (represented by line 21 shown in FIG. 3) from the area of the catcher 32 that is contacted by the lip portion 18. Alternatively or additionally, the first portion 19 of the pair of walls 10 can be spaced apart from the liquid drop contact region 30 of the catcher by a distance X (represented by line 23 in FIG. 4). When this is done, the second portion 20 of the pair of walls 10 can include an end 40 spaced apart from the liquid drop contact region 30 of the catcher 32 by a distance Y (represented by line 12 in FIG. 4), where Y≦0.5 X. Alternatively, the second portion 20 of the pair of walls 10 can include an end 40 spaced apart from the liquid drop contact region 30 of the catcher 32 by a distance Y, where 0≦Y≦0.8 mm.
It has been found that when one or more of these example configurations are used, accumulated liquid 9 may still wick up the first portion 19 of wall 10. However, when the liquid 9 contacts the second portion 20 of wall 10, the liquid begins circulating in a circular motion 11 which eventually causes the liquid 9 to move back toward liquid removal opening 5.
The pair of walls 10 can be located on either the eyelid 15 as shown in FIG. 5 or the catcher 32 as shown in FIG. 6. Depending on its location, the portion 19 or 20 of each wall 10 that is contactable with either the eyelid 15 or the catcher 32 can be contoured to substantially mirror the shape of either the eyelid 15 or the catcher 32, as is shown in FIGS. 5 and 6. The pair of walls 10 can be integrally formed on either of the catcher 32 or the eyelid 15. Alternatively, the pair of walls 10 can be attached to either the catcher 32 or the eyelid 15 using any known technique. For example, the pair of walls 10 can be glued or fastened to either the catcher 32 or the eyelid 15.
At least a portion 19 or 20 of each of the pair of walls 10 can be made from a polymeric material to improve the seal between the pair of walls 10 and either the catcher 32 or the eyelid 15 depending on the location of the pair of walls 10. At least a portion 19 or 20 of each of the pair of walls 10 can be made from a hydrophobic material to help guide the liquid 9 back toward the liquid removal opening 5 of the catcher 32.
The invention has been described in detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention.
Patent Application
20070291085
