Patent Publication Number: US-7722177-B2

Title: System for loading ink sticks configured for lateral anti-skewing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   Reference is made to commonly-assigned co-pending U.S. patent application Ser. No. 11/605,015, which was filed on Nov. 28, 2006 and is entitled “INTERMEDIATE SIDE SLOT VERTICAL INK CONSTRAINT WITH OFFSET SUPPORT,” by Brent R. Jones et al., and to commonly-assigned co-pending U.S. patent application Ser. No. 11/605,100, which was also filed on Nov. 28, 2006 and is entitled “LATERAL ANTI-SKEWING SOLUTION FOR SOLID INK”, by Brent R. Jones et al., the disclosure of both applications are hereby expressly incorporated herein by reference in their entireties. 
   TECHNICAL FIELD 
   This disclosure relates generally to ink printers, the ink sticks used in such ink printers, and the devices and methods used to provide ink to such printers. 
   BACKGROUND 
   Solid ink or phase change ink printers conventionally receive ink in a solid form, either as pellets or as ink sticks. The solid ink pellets or ink sticks are typically placed in an “ink loader” having a feed chute or channel. A feed mechanism delivers the solid ink sticks through the feed channel to a heater assembly. In some solid ink printers, gravity pulls solid ink sticks through the feed channel to the heater assembly. Typically, a heater plate (“melt plate”) in the heater assembly melts the solid ink impinging on it into a liquid that is delivered to a print head for jetting onto a recording medium. U.S. Pat. No. 5,734,402 for a Solid Ink Feed System, issued Mar. 31, 1998 to Rousseau et al.; and U.S. Pat. No. 5,861,903 for an Ink Feed System, issued Jan. 19, 1999 to Crawford et al., the disclosures of which are incorporated herein by reference, describe exemplary systems for using solid ink sticks (“phase change ink sticks”) in a phase change ink printer. 
     FIG. 1  is a simplified cross-sectional view of a prior art feed channel  20  and one of a plurality of phase change ink sticks  24 . The previously known phase change ink sticks  24  have included various top surfaces  28 , bottom surfaces  32 , side surfaces  36 , and side surfaces  40 . These surfaces may be complementary or otherwise correspond to ink loader features to support and guide the ink sticks into optimal feed/melt positions. Some horizontal or near horizontal ink loaders have included “lower laterally offset” or “bottom laterally offset” ink stick supports and/or guide rails  44  that are vertically below and laterally offset from the ink stick centers of gravity  47 . In addition to substantially supporting the weights of the ink sticks  24 , these ink loader structures  44  have also slidably engaged corresponding protruding and/or inset ink stick features  52  to guide the ink sticks  24  to melt plates (not shown) along substantially straight or other prescribed feed paths. As may be understood by viewing the structure shown in  FIG. 1 , gravity causes the side  40  of the ink stick  24  which is opposite the lower laterally offset feature  44  to lean and slide against the feed channel wall  48 . 
   Ink loaders typically hold many ink sticks at once and each individual ink stick typically must travel several times its length to reach the melt plate. The wax-like components from which phase change ink sticks are typically made are typically designed to bond to media of many different types, and, accordingly, they may become slightly sticky in some environmental conditions. Consequently, some phase change ink printers occasionally encounter intermittent sticking and slipping of ink sticks in the ink loaders as the ink sticks are pushed through the ink loaders. Ink loader length and complexity of the feed path may also contribute to the intermittent sticking of ink sticks in the feed channel. 
     FIG. 2  is a simplified cross-sectional view of a prior art feed channel  60  and a phase change ink stick  24 . In channel  60 , an additional support  64  protrudes from the lateral side that is opposite the lower offset features  68 . The support  64  helps reduce the opportunity for intermittent sticking by enabling gravity to cause the ink stick  24  to pivot somewhat (e.g., as indicated generally by the arrow  72 ) about the lower laterally offset features  68  and slidably lean against the side rail feature  64 . While side rail features, such as support  64 , have worked reasonably well to properly position and orient ink sticks  24  in their path to a melt plate, sometimes reverse pivoting or other dislodging of the ink sticks  24  occurs when a printer is moved or jostled during normal use. These actions may result in misalignments of the ink sticks  24  that can lead to misalignment of the ink sticks in the feed channel and impact their progress down the feed channel. Leaning may also result in side loads in the lower guides that may amplify sticking issues arising from friction between the phase change ink sticks and the guides. 
   As emerging technologies reduce the time for generating solid ink images, faster solid ink delivery systems must be developed. Increased speed, however, may increase the risk of intermittent sticking. One proposed solution is to widen the phase change ink sticks to increase melt surface areas to generate more ink as an ink stick is melted. Increasing the size of the ink sticks may result in greater size tolerances for manufacturing the ink sticks and for construction of the corresponding ink loaders. These increased tolerances may lead to larger clearances between the ink sticks and corresponding ink loader guide features. These enlarged clearances could allow undesirable skewing and jamming of the ink sticks in some ink loaders, especially with ink sticks widened so their width-to-length ratios (“aspect ratios”) become disadvantageous. Therefore, enhanced control of ink sticks as they move through a feed channel is desirable. 
   Solutions to these issues encountered with the feeding of solid ink sticks to a melt plate through a feed channel are provided by the ink stick configurations disclosed in the two co-pending patent applications cross-referenced above. These ink stick configurations interact with anti-skewing features in the feed channels to maintain proper orientation of the ink sticks in the feed channel. The anti-skewing features, such as side rails that extend into side slots in the ink sticks, cannot extend into the loading area for the ink sticks when the insertion direction is generally orthogonal to the feed channel. If they did, they would engage the bottom of the ink stick and prevent it from dropping onto the bottom support extending from the channel. 
   SUMMARY 
   A solid ink stick receiver for a solid ink stick loader is configured to receive and orient solid ink sticks so the skew limiters in a solid ink stick are generally aligned to receive longitudinal guide rails in a feed channel of the loader. The solid ink receiver configuration includes a pair of generally upright sidewalls separated by a distance that corresponds to an ink stick body width, and a set down area having at least one bottom support with a top surface that is located at a position that enables at least one skew limiter in a side of the ink stick to be generally aligned with a longitudinal guide rail in a feed channel. An insertion opening for the ink stick receiver may also include an anti-rotation stub to help prevent rotation of the solid ink stick about a vertical axis as the ink stick is being inserted into the receiver. 
   An ink stick may be configured to take advantage of the anti-rotation stub in the ink stick receiver. Such an ink stick includes an ink stick body having a width that extends from one side to another side and a length that extends from a front surface of an ink stick to a rear surface of the ink stick, and an anti-rotation inset on at least one side of the ink stick. The anti-rotation inset interacts with the anti-rotation stub of the ink stick receiver to help prevent rotation of the solid ink stick about a vertical axis as the ink stick is being inserted into the receiver. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a simplified cross-sectional view of a prior art feed channel and a phase change ink stick within the feed channel. 
       FIG. 2  is a simplified cross-sectional view of another prior art feed channel and the phase change ink stick of  FIG. 1 . 
       FIG. 3  is a perspective view of an exemplary phase change ink printer. 
       FIG. 4  is a partial top perspective view of the phase change ink printer of  FIG. 3  with its ink access cover open. 
       FIG. 5  is a side sectional view of a feed channel of the solid ink feed system of the phase change ink printer of  FIG. 3  (and  FIG. 4 ) taken along line  5 - 5  of  FIG. 4 . 
       FIG. 6  is a simplified cross-sectional view of the feed channel of  FIG. 5  taken along line  6 - 6  of  FIG. 5 . 
       FIG. 7  is a top/front perspective view of the insertion key plate and the feed key plate of the phase change ink printer of  FIG. 3  (and  FIG. 4 ). 
       FIG. 8  is a top/back perspective view of exemplary ink sticks configured for use in the phase change ink printer of  FIG. 3  (and  FIG. 4 ,  FIG. 5 ,  FIG. 6 , and  FIG. 7 ). 
       FIG. 9  is a top/front perspective view of one of the exemplary ink sticks of  FIG. 8 . 
       FIG. 10  is a top/front perspective view of another exemplary alternative ink stick. 
       FIG. 11  is a simplified cross-sectional view of the feed channel of  FIG. 5  taken along line  11 - 11  of  FIG. 5  with one of the exemplary ink sticks of  FIG. 8  therein. 
       FIG. 12  is a simplified cross-sectional view of an alternative feed channel from the perspective of line  12 - 12  of  FIG. 5 . 
       FIG. 13  is a simplified cross-sectional view of an ink stick receiver into which solid ink sticks may be loaded before being urged into the feed channel of  FIG. 5 . 
       FIG. 14  is a side view of the ink stick receiver shown in  FIG. 13 . 
       FIG. 15  is an embodiment of an ink stick having skew limiters and an anti-rotation inset that cooperates with the ink stick receiver as shown in  FIG. 14  to reduce vertical rotation of an ink stick during insertion of the stick. 
   

   DETAILED DESCRIPTION 
   Like reference numerals refer to like parts throughout the following description and the accompanying drawings. Some illustrations are shown as a mirror image for feature clarification. 
     FIG. 3  is a perspective view of an exemplary phase change ink printer  110 . Printer  110  includes an outer housing having a top surface  112  and side surfaces  114 . A user interface display, such as a front panel display screen  116 , displays information concerning the status of the printer, and user instructions. Buttons  118  or other control actuators for controlling operation of the printer are adjacent the user interface window, or may be at other locations on the printer. An ink jet printing mechanism (not shown) is contained inside the housing. Such a printing mechanism is described in U.S. Pat. No. 5,805,191, entitled Surface Application System, to Jones et al, and U.S. Pat. No. 5,455,604, entitled Ink Jet Printer Architecture and Method, to Adams et al, the disclosures of which are incorporated herein by reference. The top surface of the housing includes a hinged ink access cover  120  that opens (see  FIG. 4 ) to provide the user access to an ink feed system (see  FIG. 5 ) contained under the top surface of the printer housing that delivers ink to the printing mechanism. 
     FIG. 4  is a partial top perspective view of the phase change ink printer  110  with its ink access cover  120  open. As at least partially discernable in  FIG. 4 , the ink access cover  120  is attached to an ink load link  122  so that when the ink access cover  120  is raised, the ink load link  122  slides and pivots to an ink load position. The interaction of the ink access cover  120  and the ink load link  122  is described in U.S. Pat. No. 5,861,903 for an Ink Feed System, issued Jan. 19, 1999 to Crawford et al., the disclosure of which is incorporated herein by reference, though with some differences noted below. Opening the ink access cover  120  reveals an insertion key plate  126  having keyed openings  124 A-D. Each keyed opening  124 A,  124 B,  124 C,  124 D provides access to a feed key plate  327  having respective keyed openings  328 A,  328 B,  328 C,  328 D (see  FIG. 5  and  FIG. 7 ) positioned at the insertion end(s) of respective individual feed channels  129 A,  129 B,  129 C,  129 D (see, e.g.,  FIG. 5 ) of the solid ink feed system. In the exemplary embodiment, the feed key plate  327  (see  FIG. 5  and  FIG. 7 ) is oriented generally perpendicularly to the insertion key plate  126 . As discussed further below (see  FIG. 5  and  FIG. 7 ), the phase change ink printer  110  is configured to receive ink sticks  330 A,  330 B,  330 C, and  330 D inserted through the respective keyed openings  124 A,  124 B,  124 C,  124 D (as indicated generally by respective insertion direction arrows  131 A,  131 B,  131 C, and  131 D) and to advance or feed the ink sticks  330 A-D through the respective keyed openings  328 A,  328 B,  328 C,  328 D and further through the respective feed channels  129 A,  129 B,  129 C,  129 D. 
     FIG. 5  is a side sectional view of feed channel  129 C of the solid ink feed system of the phase change ink printer  110  taken along line  5 - 5  of  FIG. 4 . Each longitudinal feed channel  129 A-D is configured to receive respective ink sticks  330 A-D of respective colors. For example, ink stick  330 A is yellow, ink stick  330 B is cyan, ink stick  330 C is magenta, and ink stick  330 D is black, ( FIG. 8 ). The ink sticks are inserted through the respective keyed openings  124 A-D (see also  FIG. 4 ) of the insertion key plate  126 . The ink sticks  330 A-D are then advanced through the respective keyed openings  328 A-D (see also  FIG. 7 ) of the feed key plate  327  to the respective melt plates  132 A-D. For clarity of exposition,  FIG. 5  focuses on feed channel  129 C and in  FIG. 5  ink stick  330 C is illustrated without key features. In the exemplary embodiment, feed channels  129 A,  129 B, and  129 C are likewise configured and they extend, respectively, from keyed openings  124 A,  124 B, and  124 D. 
   With continued reference to  FIG. 5 , feed channel  129 C has a longitudinal feed direction, indicated generally by direction arrow  337 C, from its insertion end  124 C to its melt end adjacent to the melt plate  132 C. The melt plate  132 C melts the solid ink stick  330 C into a liquid form. The melted ink drips through a gap  133 C between the melt end of the feed channel  129 C and the melt plate  132 C, and into a liquid ink reservoir (not shown). Feed channel  129 C has a longitudinal dimension extending from the insertion end to the melt end, and a lateral dimension substantially perpendicular to the longitudinal dimension. Feed channel  129 C includes a push block  134 C driven by a driving force, such as a constant force spring  136 C, to push ink stick  330 C and/or a succession of ink sticks  330 C along the length of feed channel  129 C toward the melt plate  132 C that are at the melt end of each feed channel. The tension of the constant force spring  136 C drives the push block  134 C toward the melt end of the feed channel  129 C. As described in U.S. Pat. No. 5,861,903, the disclosure of which is incorporated herein by reference, the ink load linkage  122  (see also  FIG. 4 ) is coupled to a yoke  138 C, which is attached to the constant force spring  136 C mounted in the push block  134 C. The attachment to the ink load linkage  122  pulls the push block  134 C toward the insertion end of the feed channel  129 C when the ink access cover  120  (see  FIG. 4 ) is raised to reveal the insertion key plate  126 . 
   A lower portion of the feed channel  129 C includes a longitudinal feed channel support/guide rail  140 C and defines an accompanying longitudinal feed channel support/guide trough or groove  141 C adjacent and parallel to the feed channel support/guide rail  140 C (see also  FIG. 6 ). The feed channel support/guide rail  140 C and the feed channel support/guide groove  141 C are laterally offset from the central longitudinal axis of the feed channel  129 C (see  FIG. 6 ), and are designed to support and guide a bottom surface of the ink stick  330 C as discussed further below. Additionally, the feed channel  129 C includes a longitudinal feed channel side support/guide rail  147 C extending laterally inwardly from about the vertical midpoint of the lateral side wall  144 C (see also  FIG. 6 ). The rail  147 C, its opposite side counterpart and the complementary skew limiting features in an ink stick need not be located near the vertical midpoint. The feed channel side support/guide rail  147 C extends from a position near the melt end of the feed channel  129 C to, but not into, the key plate  327  insertion area. This arrangement enables an ink stick to be inserted without the guide rail  147 C interfering with the downward insertion of the ink stick. As used herein, the term “support” refers to a surface or structure that bears all or a portion of the weight of an object and the term “guide” refers to a surface or structure that assists in maintaining alignment or orientation of an object. In a horizontal orientation, the full mass of an ink stick bears on supports as gravity pulls the ink to these supports. As the loader orientation becomes more vertical, force from ink stick mass is directed more to the stack of ink sticks and the melt plate into which they progress than the support surfaces. In this case, the support may become guidance or constraining surfaces. 
     FIG. 6  is a simplified cross-sectional view of the feed channel  129 C taken along line  6 - 6  of  FIG. 5 . For clarity of exposition  FIG. 6  focuses on feed channel  129 C. In the exemplary embodiment, feed channels  129 A,  129 B, and  129 D are likewise configured. As at least partially discernable in  FIG. 6 , the feed channel  129 C is defined by lateral side walls  142 C,  144 C that are substantially vertical, and a bottom  146 C, which may be recessed, open, or partially open. The transverse dimension of the feed channel  129 C is between its lateral side walls  142 C,  144 C. The longitudinal feed channel support/guide rail  140 C and the adjacent longitudinal feed channel support/guide groove  141 C are included in a lower portion of the feed channel  129 C, preferably near the bottom  146 C. As noted above, the feed channel support/guide rail  140 C and the feed channel support/guide groove  141 C are parallel and laterally offset from the central longitudinal axis of the feed channel  129 C, and they are designed to receive a bottom surface of the ink stick  330 C as discussed further below. As noted above, the feed channel  129 C includes the longitudinal feed channel side support/guide rail  147 C, which extends inwardly from an elevated position relative to the lower support and about the vertical midpoint of the lateral side wall  144 C. The feed channel side support/guide rail  147 C may be non-flat or contoured so that it incorporates an ink contactor area  148 C and a constraining extension  149 C. The contactor  148 C extends laterally inward from and generally perpendicularly at a position, in the example configuration, near the vertical midpoint of the lateral side wall  142 C. The extension  149 C extends generally inward from the contactor  148 C at an angle  151 C relative to the contactor  148 C. The angle  151 C may be less than 180 degrees, such as about 150 degrees, although other angles may be used. Alternatively, the contour may be a continuous or variable radius. The contactor is intended to provide a predictable line of contact that the ink stick uses for support on that side of the channel. The extension protrudes beyond the contact to a narrower inset or waist point within an ink stick that is closer to the center of the stick so that unintended rotation of the stick is restricted. The extension limits movement, but need not contact the ink stick under normal operational conditions. The extension is configured to enable limited contact with an ink stick to an area along the contactor. 
     FIG. 7  is a top/front perspective view of the insertion key plate  126  and a feed key plate  327 . As at least partially discernable in  FIG. 7 , the perimeters of the keyed openings  124 A-D define generally U-shaped notch-like indentation or “female key features”  150 A-D. Further, keyed openings  124 A-D have respective lateral dimensions or widths  154 A-D and respective back perimeter segments or portions  158 A-D. The widths  154 A-D are all about equal to each other and the respective key features  150 A-D are mutually exclusively or uniquely positioned along the respective back perimeter segments  158 A-D. 
   As also at least partially discernable in  FIG. 7 , the feed key plate  327  defines keyed openings  328 A-D. The keyed openings  328 A-D are about the same size and shape. The perimeter of each keyed opening  328 A-D defines a pair of laterally opposing protuberances or “male key features”  362 A-D. Further, a bottom lateral corner of the perimeter of each keyed opening  328 A-D also defines a generally V-shaped or generally U-shaped notch-like indentation or “female key feature”  364 A-D. Feed keying may be provided by a feed key plate, such as the key plate  327 , or by individual feed key plates in each independent color channel, or by the more traditional features formed in the channel, in which case, no plate is used. No feed keying may be employed for a channel or one or more feed keying features may be provided on any, all, or any combination of, sides, top, or bottom of a channel. 
     FIG. 8  is a top/back perspective view of exemplary ink sticks  330 A-D configured for use with the phase change ink printer  110 . In the exemplary embodiment, each of the ink sticks  330 A-D is formed of a generally rectilinear ink stick body, although other volumetric shapes may be used. Each of the sticks  330 A-D, as depicted, includes a bottom surface  380 A-D (obscured in  FIG. 8 ), a top surface  384 A-D, a pair of lateral side surfaces  388 A-D, substantially flat front surfaces  392 A-D (obscured in  FIG. 8 , but see  FIG. 9 ), and back surfaces  396 A-D. The front surfaces  392 A-D are substantially parallel to the respective back surfaces  396 A-D and are substantially perpendicular to the respective lateral side surfaces  388 A-D. However, ink sticks  330 A-D are merely exemplary and in alternative embodiments the respective surfaces of the ink stick bodies need not be substantially flat, nor need they be substantially parallel or perpendicular to one another. Ink stick bodies need not be generally rectilinear and may have 3, 5, 6 or any reasonable number of sides, with or without parallel ends. Consequently, as used herein the term “side” may refer to any such surface of an ink stick. Other shapes of the side and end surfaces are also possible, including curved surfaces. Nevertheless, the present descriptions should aid the reader in visualizing, even though the surfaces may have three dimensional topographies, or be angled with respect to one another. The ink sticks  330 A-D may be formed by pour molding, compression molding, forging, or any other suitable technique or combination thereof. 
   Further, as at least partially discernable in  FIG. 8 , the back surfaces  396 A-D include respective ridges or “male features”  404 A-D extending from the respective top surfaces  384 A-D to about ¾ of the way towards the respective bottom surfaces  380 A-D. The male features  404 A-D are shaped and positioned to complement and be received by the respective female key features  150 A-D of the respective keyed openings  124 A-D of the insertion key plate  126 . The features  404 A-D function as keys to help exclude ink sticks of the wrong color from being inserted through each of the corresponding complementary keyed openings  124 B,  124 C, and  124 D (see  FIG. 7 ). 
   As also at least partially discernable in  FIG. 8 , the pairs of generally lateral side surfaces  388 A-D define respective pairs of laterally opposing generally U-shaped notch-like indentations or “female features”  408 A-D that extend from the respective back surfaces  396 A-D to the respective front surfaces  392 A-D. These features operate as skew limiters as described below. The bottom surfaces  380 A-D also include respective ridges or “male features”  410 A-D that extend fully or partially from the respective front surfaces  392 A-D to the respective back surfaces  396 A-D. These features function as guiding supports as described below. The female features  408 A-D may interact with respective male key features  362 A-D of the respective keyed openings  328 A-D of the feed key plate  327  or alternative feed keying features. These features also enable the ink sticks  330 A-D to be constrained by rails  143 A-D and  147 A-D as the ink sticks travel through the respective feed channels  129 A-D. The male features  410 A-D are also configured to slide in the respective feed channel support/guide grooves  141 A-D as the ink sticks  330 A-D travel through the respective feed channels  129 A-D. These features are elevationally offset from the bottom surface and are complementary to the supports in the feed channel so the engagement of the features and the supports function as guiding supports as described below. 
   The ink sticks  330 A-D of  FIG. 8  have respective lateral centers of gravity between their respective pairs of lateral side surfaces  388 A-D, and have respective vertical centers of gravity between the respective top surfaces  384 A-D and the bottom surfaces  380 A-D. In the exemplary embodiment, the ink sticks  330 A-D have substantially uniform weight densities, and the lateral centers of gravity are, excepting asymmetrical features, approximately midway between the respective pairs of lateral side surfaces  388 A-D. In alternative embodiments each of the exemplary male features  404 A-D may be replaced with one or more longer ridges or other suitable protuberances that may span the entire back surfaces  396 A-D, and each of the male features  410 A-D may be replaced with one or more shorter ridges or other suitable protuberances that need not necessarily span the entire bottom surfaces  380 A-D. 
     FIG. 9  is a top/front perspective view of the ink stick  330 C.  FIG. 9  focuses on the ink stick  330 C for clarity of exposition, although the ink sticks  330 A,  330 B, and  330 D are similarly configured. The respective maximum lateral dimensions or maximum widths of the ink sticks  330 A-D are no wider than the lateral dimensions of the respective feed channels  129 A-D between their respective side walls  142 A-D and  144 A-D, and in the exemplary embodiment, are only fractionally smaller than the lateral dimensions of the respective feed channels  129 A-D. 
   As also at least partially discernable in  FIG. 9 , the ink sticks  330 A-D have the same or nearly the same respective minimum lateral dimensions or core widths  512 A-D between their respective anti-skew features  408 A-D. The lengths  504 A-D and the core widths  512 A-D are engineered to, among other things, provide a significantly higher length-to-core width ratio (“core aspect ratio”) for each of the ink sticks  330 A-D over the generally central, waist or “core,” portion of each ink stick than the respective length-to-maximum width ratio (“overall aspect ratio”). The favorable core aspect ratio discourages longitudinal skewing and consequent jamming of the ink sticks  330 A-D in the respective feed channels  129 A-D. Incorporation of the anti-skew features  408 A-D enables the ink sticks  330 A-D to have increased overall frontal melt areas and also increased lateral cooling surface areas. In one embodiment, one indentation may be located near the vertical center of mass between the top and the bottom of an ink stick and configured to increase peripheral surface area of the stick. These features promote more uniform temperature changes of the ink material and thus ameliorate or avoid cracking and/or deformation of the ink sticks  330 A-D during manufacturing, handling, and printing operations. Although the anti-skew features  408 A-D in the exemplary embodiment are positioned approximately midway between the respective bottom surfaces  380 A-D (obscured in  FIG. 9 ) and the respective top surfaces  384 A-D, they may be at other positions intermediate the respective bottom surfaces  380 A-D and the respective top surfaces  384 A-D in alternative embodiments. These features are positioned far enough from the respective bottom surfaces  380 A-D and the respective top surfaces  384 A-D that these alternative embodiments of the ink sticks  330 A-D are not undesirably weakened or made too fragile for normal handling. Further, the anti-skew features  408 A-D in the exemplary embodiment are configured to provide a core aspect ratio of at least about 1.2:1. As an example: an ink stick with a width 2 times its length could have similar female features that extend inward about 25% of the width, yielding a core aspect ratio of about 1:1. Although alternative embodiments may provide lower or higher core aspect ratios, the core aspect ratio of 1.2:1 appears realistic for maintaining ink stick robustness, manufacturability, and suitable melt mass for a given frontal surface area or cross-section. Any appreciable improvement in the core aspect ratio is likely to benefit feed reliability. Thus, one of the skew limiters may have a width that is about ten (10) to about forty (40) percent of the width of the ink stick body. Depending on ink stick size and mass, dimensional influence or structural robustness may override a specific aspect ratio goal. In any event, the anti-skew features reduce the constrainable width, preferably to 85% or less of the ink stick width in this region without such features. Also, the anti-skew features  408 A-D in alternative embodiments need not necessarily be equally sized. Some size differences may be used to achieve specific desired ink stick masses, which may facilitate achieving uniformity across sets of differently colored ink sticks. For example, one indentation may be larger than the other one as a result of a greater volume of material being removed from the stick to form the indentation. In other embodiments, the widths of the two skew limiters sum to a distance that produces a waist that is preferably about ninety (90) percent or less than the length of the ink stick. A skew limiter may also only be present on only one side of an ink stick on account of asymmetrical features or other considerations. The skew limiting features  408 A-D are shown as being uninterrupted along the length of the ink stick body. Note that the waist width, which is intended to be guided by rails in the loader, permits the anti-skew features to be interrupted by keying features, other insets, or truncated portions of the stick side above and/or below the anti-skew feature at an equal, lesser or greater depth than the anti-skew features. 
     FIG. 10  is a top/front perspective view of another exemplary alternative ink stick  630 C, which may be used for configuring alternative embodiments of other ink stick colors.  FIG. 10  focuses on the ink stick  630 C for clarity of exposition. As at least partially discernable in  FIG. 10 , the alternative ink stick  630 C defines stylized lateral anti-skew features  650 C that operate similarly to the anti-skew features  408 A-D (see, e.g.,  FIG. 11 ). Ink stick  630  also includes respective stylized bottom female features  654 A-D that perform similarly to the support features  412 A-D. Alternative embodiments may also define guide features in the respective top surfaces  684 A-D. In other embodiments, the skew limiters and support features may even be configured to resemble the shape of the letter “X” or any other suitable symbolic and/or suggestive shape(s). Thus, the skew limiters may be curved or arcurate, and, in some cases, the curvature may be significant. As depicted in the configuration of  FIG. 10 , the supporting area of the interfacing rail  148 C need not support weight in the same vector as the lower guide  141 C to maintain the advantage over a lean support that is directly lateral, as done in the prior art. 
   In exemplary operation of phase change ink printer  110 , phase change ink printer  110  uses four colors of ink (e.g., yellow, cyan, magenta, and black). First, a user opens the ink access cover  120 . The keyed openings  124 A-D aid the user in inserting (as generally indicated by the respective directional lines  131 A-D) only respective ink sticks  330 A-D of the proper colors into each respective feed channel  129 A-D. After the user inserts ink sticks  330 A-D through the keyed openings  124 A-D, the user closes the ink access cover  120 . Provided that the user has inserted the proper series or type of ink sticks  330 A-D, push blocks  134 A-D push the respective ink sticks  330 A-D along their respective corresponding feed channels  129 A-D (as generally indicated by respective directional lines  337 A-D) towards the respective melt plates  132 A-D. 
     FIG. 11  is a simplified cross-sectional view of the feed channel  129 C taken along line  11 - 11  of  FIG. 5  with one of the exemplary ink sticks  330 C therein.  FIG. 11  focuses on the feed channel  129 C for clarity of exposition. As an ink stick  330 C advances through the feed channel  129 C, the ink stick  330 C remains substantially upright but does pivot or tilt slightly as generally indicated by the arrow  600 . During normal operations, the feed channel side support/guide rail  143 C extends into the respective female feature  408 C but does not contact the waist of ink stick  330 C nor does the stick rest on the rail. The primary support and alignment for the ink stick  330 C within the feed channel  129 C are the engagement between the male feature  410 C and the feed channel support/guide groove  141 C and the engagement between the feed channel side support/guide rail  147 C and the female feature  408 C. Thus, the feed channel side guide rail  143 C is a non-load bearing, while the feed channel side support/guide rail  147 C bears the weight load  604 C. Little or no lateral force or load occurs on the sides of the feed channel guide  141 C when the upper surface of the ink stick female feature  408 C is horizontal, relative to the view depicted in  FIG. 11 . This feature may be angled, however. Additionally, the upper surface of one of the skew limiters may be located closer to the top surface of the ink stick than the upper surface of the other skew limiter. The support/guide rail  147 C and rail  143 C may take a form from a broad range of shapes, including curved, rounded, U-shaped, rectangle, square, V-shaped or combinations of such shapes. The reader should also understand that these exemplary listed forms may be further altered by minor features such as varying radii, localized notches, draft angles, and the like. 
   The minimal contact between an ink stick  330 A-D and its respective feed channel  129 A-D reduces opportunities for chips or flakes from the ink stick to interfere with the progress of the ink stick through the feed channel. Additionally, engagements between the supports  410 A-D (of the respective ink sticks  330 A-D) and the respective feed channel support/guide grooves  141 A-D (of the respective feed channels  129 A-D) and the engagements between the feed channel side support/guide rails  147 A-D (of the respective feed channels  129 A-D) and the respective skew limiters  408 A-D (of the respective ink sticks  330 A-D) work to reduce skewing within the channels. This action helps maintain proper orientation of the ink sticks  330 A-D as the ink sticks  330 A-D progress along the lengths of the respective feed channels  129 A-D to the respective melt plates  132 A-D. 
   With the ink sticks  330 A-D properly aligned within the respective feed channels  129 A-D, the ink sticks  330 A-D meet the respective melt plates  132 A-D generally normal to the melt plate surfaces, which promotes even melting of the ink sticks  330 A-D against the melt plates  132 A-D. Even melting reduces the formation of unmelted slivers, which might otherwise form at the trailing end of each ink stick  330 A-D, and thus reduces the potential for such unmelted slivers to slip through the respective gaps  133 A-D between the ends of the feed channels  129 A-D and the melt plates  132 A-D. Passage of unmelted slivers is uncontrolled and may cause color mixing or may impair the performance of certain portions of the phase change ink printer  110 . Guiding the ink sticks  330 A-D to maintain their alignments in the respective feed channels  129 A-D also ameliorates and/or prevents jamming due to skewing of the ink sticks  330 A-D as they move through the respective feed channels  129 A-D. 
   Engagement between the support  410 A-D of the respective ink sticks  330 A-D and the respective feed channel support/guide grooves  141 A-D of the respective feed channels  129 A-D and engagement between the feed channel side support/guide rails  147 A-D of the respective feed channels  129 A-D and the respective skew limiters  408 A-D also reduce “steering” effects that the push blocks  134 A-D may have when acting on the respective back surfaces  396 A-D of the ink sticks  330 A-D. Thus, laterally offset pressure by the push blocks  134 A-D on the respective ink sticks  330 A-D is of lesser concern, and maintaining a more exact lateral feed friction balance with the force exerted by the push blocks  134 A-D on the respective ink sticks  330 A-D is less critical than with some other designs. 
   Additionally, the feed channel side guide rails  143 A-D and the respective skew limiters  408 A-D, in conjunction with the feed channel side support/guide rails  147 A-D, respectively, work to inhibit reverse pivoting and/or other dislodging of the ink sticks  330 A-D in the respective feed channels  129 A-D. This inhibition occurs as the skew limiters  408 A-D abut or stop against the feed channel side guide rails  143 A-D and/or the feed channel side support/guide rails  147 A-D when the phase change ink printer is handled, moved, transported, or otherwise jostled in a manner which might otherwise dislodge the ink sticks  330 A-D. 
   In the exemplary embodiment, the portions  148 A-D of the respective feed channel side support/guide rails have arcuate portions  147 A-D that bend into the respective portions  149 A-D such that the surface areas bearing the respective vertical loads  604 A-D are quite small. The reduced surface areas of these load bearing surfaces reduce the likelihood that the ink sticks are smeared by the rails and that fewer ink particulates are dislodged from the ink sticks. Therefore, ink smearing and ink particulates are less likely to be contributors of undesirable friction in the feed channel. In alternative embodiments, the feed channel side support/guide rails  147 A-D and/or the ink sticks  330 A-D may be constructed with depressions, discontinuities, or the like for intermittent contact with the respective vertical loads  604 A-D along their respective lengths, and/or may include substantially flat or planar surfaces, notches and/or other complimentary features for bearing the respective vertical loads  604 A-D. Further,  FIG. 12  is a simplified cross-sectional view of an alternative feed channel  729 C from the perspective of line  12 - 12  of  FIG. 5 . As at least partially discernable in  FIG. 12 , an alternative phase change ink printer is configured and operates in a like manner as the phase change ink printer  110  except that in lower portions of similarly configured alternative embodiments for feed channels  729 A-D ( FIG. 12  focuses on feed channel  729 C for clarity of exposition) the longitudinal feed channel support/guide rails  140 A-D and the accompanying longitudinal feed channel support/guide grooves  141 A-D are separated from the floor of the feed channels  729 A-D. 
     FIG. 13  is a simplified cross-sectional view of an ink stick receiver that receives solid ink sticks and orients the solid ink sticks so the skew limiters of a solid ink stick are generally aligned to receive the longitudinal guide rails in the feed channel. An ink stick receiver is the portion of an ink loader into which a solid ink stick is loaded. An ink stick receiver includes an insertion opening, which is typically located in a key plate, and a set down area on which an ink stick rests upon insertion. The ink stick receiver may also refer to the portion of the feed channel adjacent to the set down area where a solid ink stick enters a feed path configured with skew limiting rails or guides. This area of the receiver includes the ink receiving end of a skew limiting guide that extends from at least one side wall of the feed channel. 
   An exemplary ink stick receiver is shown in  FIG. 13 . The ink stick receiver  500  includes a pair of generally upright sidewalls  504 ,  508 . The sidewalls  504 ,  508  are separated from one another by a distance that corresponds to an ink stick body width as shown in the figure. The relative close tolerance between wall separation distance and the width of the ink stick helps maintains proper vertical orientation of the solid ink sticks placed in the receiver. The embodiment of the receiver depicted in  FIG. 13  also includes a bottom support  510  and a bottom support  514 . The bottom support  514  is arcuate to receive the support protrusion of the ink stick. The bottom supports are located at positions to support the ink stick and orient the stick so that the skew limiters in the ink stick are generally aligned with the longitudinal guide rails  143 ,  147  in the feed channel  729 , for example. In one embodiment, the bottom support may be a continuation of a support in the receiver area that extends through the feed channel towards the melt plate. In another embodiment, the bottom support is only present in the receiver area. One, two, or more bottom supports may be used in the receiver area as a set down surface or surfaces for an ink stick as it is inserted. 
   In an alternative embodiment, the bottom support  510  may extend from the sidewall  504  towards the sidewall  508  to a position short of the support protrusion of the ink stick. This relatively flat bottom support may have a top surface  520  that holds the ink stick so the skew limiters in the lateral sides of the ink stick are generally aligned with the longitudinal guide rails in the feed channel. As shown in the figure bottom supports  510 ,  514  are extensions from sidewalls  504 ,  508 , respectively. Alternatively, the bottom supports may be provided in a manner that is independent of the sidewalls. 
   To facilitate insertion of the ink stick into the ink receiver, the sidewalls  504 ,  508  may be tapered. The tapering provides a larger opening for the insertion of the ink stick and then the increasing thickness of the sidewalls orients the ink stick appropriately for transition to the feed channel. The distance between the sidewalls at the bottom of the tapered walls corresponds closely to the width of an ink stick to help constrain movement of the ink stick within the ink receiver without unnecessarily impeding insertion of the ink stick. 
   As shown in  FIG. 14 , the ink receiver  500  may be covered with an insertion plate having an opening  538 . The ink stick is shown in a partially inserted position to emphasize the insertion opening  538  and the anti-rotation stub  530 . The stub  530  helps prevent forward stick rotation about a vertical axis by interfacing with an anti-rotation inset  544  of the ink stick. The opening is configured to correspond to the width, length, and key(s) of a solid ink stick. The insertion plate is depicted as having an anti-rotation stub  530  that extends from a side edge of an opening  538  in the insertion plate. The anti-rotation stub  530  is received within the anti-rotation inset  544  along the side of the ink stick, as depicted in  FIG. 15 , immediately behind the front of the ink stick. Additionally, the sides of the insertion opening  538  may include one or more keys. In  FIG. 14 , the rear edge  548  complements the keys on the ink stick to help reduce the likelihood that an improper ink stick is inserted in the ink receiver. The key in the rear edge may be a protrusion key that is received in an indentation key in an ink stick. Alternatively, the key may be an indentation key in the rear edge that receives a protrusion key from a rear face of an ink stick inserted through the opening  538 . The ink stick key and the key on the rear edge have a depth that is at least 1.5 times the depth of the anti-rotation inset  544 . 
   Once the ink receiver is installed at the entry end of a feed channel, ink sticks may be inserted with relative ease. The sidewalls and bottom support(s) help to align the skew limiters  408  in the ink sticks with the longitudinal guide rails  143 ,  147  in the feed channel. The anti-rotation stubs interact with the anti-rotation insets to maintain the vertical orientation of the ink sticks. This feature is especially beneficial for use with ink sticks having a canted front face. Once the ink sticks are inserted into the receiver, the push block may be engaged to urge the ink sticks into the feed channel so the bottom support and the longitudinal guide rails in the feed channel continue to maintain proper alignment of the ink sticks until they are delivered to the melt plate. 
   Those skilled in the art will recognize that numerous modifications can be made to the specific implementations described above. For example, those skilled in the art will recognize that the support/guide rail(s) of the feed channel(s) and the complementary features of the ink sticks may have numerous other suitable shapes other than the particular shapes illustrated. Additionally, the various male-female implementations of the various key and/or support/guide features may be suitably reversed or inverted. Furthermore, numerous other configurations of the feed channel, key plate, and other components of the ink feed system can be constructed. Therefore, the following claims are not to be limited to the specific embodiments illustrated and described above. The claims, as originally presented and as they may be amended, encompass variations, alternatives, modifications, improvements, equivalents, and substantial equivalents of the embodiments and teachings disclosed herein, including those that are presently unforeseen or unappreciated, and that, for example, may arise from applicants/patentees and others.