Ink loader with ink stick retractor

A solid ink loading system for a phase change ink imaging device includes an ink loader having a first end, a second end, and at least one feed channel extending between the first and the second end. The at least one feed channel includes an insertion region intermediate the first and the second end where ink sticks enter the at least one feed channel. The at least one feed channel is configured to guide ink sticks in a feed direction from the insertion region toward the second end. An ink stick retractor is configured for movement between a forward position and a rearward position substantially parallel to at least a portion of the at least one feed channel. The forward position is closer to the second end of the feed channel than the first position. The ink stick retractor is configured to selectively move ink sticks in the at least one feed channel in a retraction direction toward the first end.

TECHNICAL FIELD

This disclosure relates generally to phase change ink printers, and in particular to solid ink loaders for use in such printers.

BACKGROUND

Phase change ink imaging products encompass a wide variety of imaging devices, such as ink jet printers, facsimile machines, copiers, and the like, that are configured to utilize phase change ink to form images on recording media. Some of these devices use phase change ink in a solid form, referred to as solid ink sticks. Imaging devices that utilize solid ink sticks are typically provided with feed channels. Ink sticks are inserted into the feed channels through insertion openings and then urged by one or more drive members, gravity, or a combination thereof in a feed direction toward melting devices located at one end (i.e., the melt ends) of the channels where the ink sticks are melted to a liquid ink suitable for jetting onto recording media.

Each feed channel has an insertion area or region where ink sticks are received after passing through the corresponding insertion opening. To enable insertion of ink sticks into the feed channels, drive members, such as push blocks, are retracted to a rearward position beyond the insertion regions of the channels to provide clearance for ink sticks to be inserted into the insertion regions of the feed channels in front of the push blocks. After ink stick insertion has been completed, the push blocks are moved from the retracted position to apply an urging force to the trailing end of the last ink stick inserted into the channels. If there is space in front of the last ink stick, the urging force causes the ink stick to move forward in the channel until the ink stick abuts the trailing end of the previously inserted ink stick or moves forward until the ink stick impinges on the melting device located at the melt end of the channel if no other ink sticks are in the channel.

If the column of ink in a channel extends far enough from the melt end of the channel toward the insertion region, the next ink stick inserted into the channel may still protrude into the insertion region of the channel after being abutted against the trailing end of the column, preventing ink sticks from being inserted into the channel, at least temporarily. The position of the insertion opening relative to the melt end of a channel therefore controls the number of ink sticks capable of being loaded into the channel at any given time in these systems. Consequently, the insertion openings of the channels are typically located as far away from the melt ends of the channels as possible to maximize the number of ink sticks capable of being loaded into the channels.

In some imaging device configurations, however, the lengths of the feed channels may be limited because the area most distant from the melt ends of the channels may be inaccessible for ink stick insertion. Consequently, the insertion openings for the feed channels of the ink loader in these devices have to be located at a location that shortens the potential length of the feed channel. Thus, the number of ink sticks (and the amount of ink) that may otherwise be loaded into the channels is decreased. A similar situation exists if there is an opportunity to increase channel length and thus ink capacity.

SUMMARY

In accordance with the present disclosure, an ink stick retraction system has been developed for use in the ink loader of a phase change ink imaging device that enables feed channels to incorporate ink stick insertion openings that are positioned at intermediate locations of the feed channel by using an ink stick retraction system. In one embodiment, a solid ink loading system for a phase change ink imaging device includes an ink loader having a first end, a second end, and at least one feed channel extending between the first and the second end. The at least one feed channel includes an insertion region intermediate the first and the second end where ink sticks enter the at least one feed channel. The at least one feed channel is configured to guide ink sticks in a feed direction from the insertion region toward the second end. An ink stick retractor is configured for movement between a forward position and a rearward position substantially parallel to at least a portion of the at least one feed channel. The forward position is closer to the second end of the feed channel than the first position. The ink stick retractor is configured to selectively move ink sticks in the at least one feed channel in a retraction direction toward the first end.

A solid ink loading system for a phase change ink imaging device includes an ink loader having a first end, a second end, and at least one feed channel extending between the first and the second end. The at least one feed channel includes an insertion region intermediate the first and the second end where ink sticks enter the at least one feed channel. The at least one feed channel is configured to guide ink sticks in a feed direction from the insertion region toward the second end. The solid ink loading system includes an ink feed system configured to move ink sticks in the feed direction from the insertion region toward the second end; and an ink stick retractor configured to move ink sticks in the retraction direction from the insertion region toward the first end.

DETAILED DESCRIPTION

For a general understanding of the present embodiments, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate like elements.

FIG. 1is a side schematic view of an exemplary embodiment of a phase change ink imaging device10configured to receive phase change ink in solid form and to melt the solid ink to a liquid for jetting onto an ink receiving surface. The device10ofFIG. 1includes an ink handling system12, also referred to as an ink loader, that is configured to receive phase change ink in its solid form as blocks of ink14, referred to as solid ink sticks. The ink loader12includes feed channels18into which ink sticks14are inserted. Although a single feed channel18is visible inFIG. 1, the ink loader12includes a separate feed channel for each color or shade of ink stick14used in the device10.

Ink sticks14are inserted into an insertion region30of the feed channels through insertion openings16. The insertion region of a feed channel refers to the portion of the guide path of the feed channel where an ink stick comes to rest upon entry into the channel. In the embodiment ofFIG. 1, the insertion openings16are positioned above the channels18so the insertion rest region30of the channel18corresponds to the portion of the channel18located substantially below the opening16. In alternative embodiments, ink sticks may be inserted into the channels through an opening in the side of the channels or the ends of the channels.

After an ink stick14has been inserted into the channel, the ink stick is moved in a feed direction F toward the melting assembly20at the end of the channel18by a mechanized delivery system and/or by gravity until the ink stick14abuts against the trailing end of a previously inserted ink stick or impinges on a melting device, such as a melt plate, at the melting assembly20if no other ink sticks are in the channel18. In the embodiment ofFIG. 1, the delivery system comprises a spring loaded push block22configured to push, or urge, ink sticks14toward the melting assembly20. If multiple ink sticks are loaded into the channel18, the push block22urges the ink sticks against each other in the channel18to form a substantially continuous column of solid ink that extends from a melting assembly20of the channel18to the push block22.

The push block22is retracted in a direction opposite the feed direction F (i.e., a retraction direction R) toward the opposite end of the channel18from the melt assembly20to enable ink sticks to be inserted into the insertion region30of the channel in front of the push block22. As explained below, the feed channels18of the ink loader12are provided with an ink stick retraction system200configured to move one or more ink sticks14located at the trailing end of the column of ink in each channel in the retraction direction R to provide a clear space in the feed channel for the insertion region30. The ability to retract ink sticks enables the insertion regions of the channels to be located at an intermediate location of the feed channel without decreasing or limiting the number of ink sticks that may be loaded into the channel.

The feed channel18guides the column of ink sticks14toward the melting assembly20at one end of the channel18where the sticks are heated to a phase change ink melting temperature to melt the solid ink to form a molten liquid ink, also referred to as melted ink. Any suitable melting temperature may be used depending on the phase change ink formulation. In one embodiment, the phase change ink melting temperature is approximately 80° C. to 130° C. The melted ink is received in a reservoir24configured to maintain a quantity of the melted ink in molten form for delivery to printing system26of the device10.

The printing system26includes at least one printhead28having inkjets arranged to eject drops of melted ink onto an ink receiving surface. Any suitable number of printheads28may be used. Each printhead may be configured with reservoir24or may be in fluid communication with reservoir24. The device10ofFIG. 1is configured to use an indirect printing process in which the drops of ink are ejected onto an intermediate surface32and then transferred to recording media, such as paper, transparency, and the like. In alternative embodiments, the device10may be configured to eject the drops of ink directly onto recording media. A layer or film of release agent is applied to a rotating member34by the release agent application assembly38to facilitate the transfer of ink images from the surface32of member34to the recording media. The rotating member34is shown as a drum inFIG. 1although in alternative embodiments member34may comprise a rotating roller, moving belt or band or other similar type of structure. A nip roller40is loaded against the intermediate surface32on rotating member34to form a nip44through which sheets of recording media52are fed in timed registration with the ink drops deposited onto the intermediate surface32by the inkjets of the printhead28. Pressure (and in some cases heat) is generated in the nip44that, in conjunction with the release agent that forms the intermediate surface32, facilitates the transfer of the ink drops from the surface32to the recording media52while substantially preventing the ink from adhering to the rotating member34.

The imaging device10includes a media supply and handling system48that is configured to transport recording media along a media path50defined in the device10that guides media through the nip44, where the ink is transferred from the intermediate surface32to the recording media52. The media supply and handling system48includes at least one media source58, such as supply tray58for storing and supplying recording media of different types and sizes for the device10. The media supply and handling system includes suitable mechanisms, such as rollers60, which may be driven or idle rollers, as well as baffles, deflectors, and the like, for transporting media along the media path50.

Media conditioning devices may be positioned along the media path50for controlling and regulating the temperature of the recording media so that the media arrives at the nip44at a suitable temperature to receive the ink from the intermediate surface32. For example, in the embodiment ofFIG. 1, a preheating assembly64is provided along the media path50for bringing the recording media to an initial predetermined temperature prior to reaching the nip44. The preheating assembly64may rely on contact, radiant, conductive, or convective heat, or any combination, to bring the media to a target preheat temperature, which in one practical embodiment, is in a range of about 30° C. to about 70° C. In alternative embodiments, other thermal conditioning devices may be used along the media path before, during, and after ink has been deposited onto the media for controlling media (and ink) temperatures and/or moisture content.

Operation and control of the various subsystems, components and functions of the imaging device10are performed with the aid of a control system68. The control system68is operably coupled to receive and manage image data from one or more image sources72, such as a scanner system or a work station connection, and to generate control signals that correspond to the image data. These signals cause the components and systems to perform the various procedures and operations for the imaging device10. The control system68includes a controller70, electronic storage or memory74, and a user interface (UI)78. The controller70comprises a processing device, such as a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) device, or microcontroller, configured to execute instructions stored in the memory74. Any suitable type of memory or electronic storage may be used. For example, the memory74may be a non-volatile memory, such as read only memory (ROM), or a programmable non-volatile memory, such as EEPROM or flash memory.

User interface (UI)78comprises a suitable input/output device located on the imaging device10that enables operator interaction with the control system68. For example, UI78may include a keypad, buttons, or other similar types of manual actuators (not shown), and a display (not shown). The controller70is operably coupled to user interface78to receive signals indicative of selections and other information input to the user interface78by a user or operator of the device. Controller70is operably coupled to the user interface78to display information to a user or operator including selectable options, machine status, consumable status, and the like. The controller70may also be coupled to a communication link84, such as a computer network, for receiving image data and user interaction data from remote locations.

The controller70is operably coupled to the various systems and components of the device10, such as the ink handling system12, printing system26, media handing system48, release agent application assembly38, media conditioning devices, and other devices and mechanisms of the imaging device10, and is configured to generate control signals that are output to these systems and devices in accordance with the print data and instructions stored in memory74. The control signals, for example, control the operating speeds, power levels, timing, actuation, and other parameters, of the system components to cause the imaging device10to operate in various states, modes, or levels of operation, referred to collectively herein as operating modes.

As depicted inFIGS. 2A and 2B, a solid ink stick14comprises a body formed of a solidified phase change ink material and shaped using a suitable fabrication process, such as casting, pour molding, injection molding, compression molding, or other known techniques. The body of the ink stick14includes end surfaces154,156, and lateral surfaces158,160,164,168. The lateral surfaces158,160,164,168of the ink stick14are configured for arrangement generally parallel to the direction of ink stick travel in a feed channel, referred to herein as the feed direction F. The lateral surfaces include a bottom surface160configured for arrangement adjacent to the base or floor of a feed channel18, a top surface164opposite the bottom surface, and a pair of side surfaces158,168that extend between the top and bottom surfaces164,160. The end surfaces154,156are configured for arrangement generally perpendicular to the feed direction F with one of the ends156facing in the feed direction F and serving as the leading end of the ink stick, and the other end surface154facing opposite the feed direction F and serving as the trailing end of the ink stick. Though ink sticks for different models may differ considerably in appearance or size, the ink stick14ofFIGS. 2A and 2Bis representative of the feature types that may be present on other ink sticks.

Ink sticks, such as ink stick14, may include a number of surface features that aid in the correct loading, guidance, feed control and support of the ink stick when used. As used herein, the term “surface features” and “features” used in relation to and ink sticks refers to topological contours, such as protrusions, recesses, grooves, and the like, that are sized, shaped, and/or otherwise configured to interact in some manner with one or more elements, devices, and members of an ink loader, or feed channel, such as key elements, guides, supports, sensors, etc. For example, the ink stick14includes insertion key feature174(FIG. 2B) that comprises a groove or notch formed in side surface168extending generally between the top surface164and the bottom surface160. The insertion opening16in the ink loader is provided with a perimeter (not shown) shaped complementarily with respect to the perimeter shape of the ink stick14.

An ink stick may also include feed control and guidance features for interacting with various structures provided in the feed channel. For example, ink stick14includes a feed key groove180formed in the bottom surface160extending from the leading end surface156to the trailing end surface154. The feed key groove180is configured to straddle a feed key (not shown) that extends from the feed channel. In alternative embodiments, the ink stick14may be provided with any suitable type of feed key feature for interacting in any manner with whatever type of keying, guidance or support members are provided in a feed channel. In addition, the ink stick14includes guide feature184near the bottom of side surface168and guide feature186near the top of side surface158for interacting with complementary structures in the feed channel to facilitate alignment of ink sticks in the channel and to limit contact between ink sticks and the feed channel structural elements, such as ribs, supports and other potentially restrictive surfaces. The typical ink loader in a desk top printer or MFP has generally been configured with linear feed channels. Various imaging products, including those of larger size, may have feed channels that are fully or partially non linear or any shape suited to the needs and available space in the product.

An ink stick may also include nesting features to facilitate alignment and feed guidance of the ink sticks in the feed channels. As depicted inFIGS. 2A and 2B, the ink stick14includes nesting features188,190at the leading end156and trailing end154, respectively, of the ink stick. The nesting features188,190are shaped complementary with respect to each other which facilitates alignment between adjacent ink sticks while maximizing load density in the feed channel. In use, when an ink stick having a nesting feature188in the leading surface156abuts an ink stick in the feed channel having complementary nesting feature190in the trailing surface154, the protruding nesting feature of one ink stick is received in the recessed nesting feature of the subsequent stick. The nesting features of the adjacent sticks cooperate to limit lateral movement of the sticks with respect to each other thereby promoting alignment of the sticks in the channel. Nesting features may not be present and if end insets and protrusions are incorporated, they need not be of a matching shape.

In addition to or as an alternative to the insertion, feed guidance, and nesting features, ink sticks may be provided with sensor features for conveying ink stick data to the print controller of the solid ink printer. The ink stick data encoded onto an ink stick may include identification information, such as color, formulation, and intended printer model, as well as printing information, such as printer settings or preferences for use with the ink stick. Sensor features comprise surface formations on the ink stick body that are configured to interact with sensors positioned at one or more locations in the insertion region and/or other portions of feed channels to convey ink stick data to the print controller of a solid ink printer.

Sensor features may have any suitable configuration that permits reliable sensor interaction, such as protrusions, recesses, reflective features, non-reflective features, and the like, depending on the type of sensor used. In the embodiment ofFIG. 2, the ink stick14includes a sensor feature192that comprises one or more contiguous insets194arrayed in the feed direction F in a lower portion of the side surface170. A single inset196is shown inFIG. 2. The locations196shown as dotted lines represent other positions where insets may be placed in the exemplary embodiment.

Ink stick data may be encoded into an ink stick by assigning data to the sensor feature192. To extract the data from the sensor feature192, the feed channel18is provided with a sensor system (not shown) capable of sensing, detecting, or being actuated by the recesses194of the sensor feature192. The sensor feature192actuates the sensors of the sensor system causing the sensor system to output signals to the printer controller70indicative of the data assigned to the sensor feature192. The controller70may then use the data to influence operations of the printer. For example, in one embodiment, once the ink stick data has been identified, the controller70may determine whether or not the ink stick is compatible with the printer and enable or disable operations accordingly.

FIG. 3depicts a side cross-sectional view of a feed channel18in greater detail. As shown, the feed channel18comprises a longitudinal chute or similar type of structure having a first end98and a second end100. A melting device104in the form of a melt plate is located at the second end100, also referred to as the melt end, of the channel18. The longitudinal portion of the channel extends between the first end98and the second end100. An insertion area or region30is located at a suitable location between the first end98and second end100of the channel proximate the insertion opening16. The term longitudinal, as applicable to an ink loader, refers to its lengthwise shape complementary to feed direction rather than widthwise in a direction across feed channels. The longitudinal portions of the feed channels may be straight, horizontal, vertical, sloped, arcuate or any combination thereof.

Each feed channel includes a feed mechanism for urging ink sticks that have been inserted into the channels toward the melting device104located at the melt end100of the channel. In the embodiment ofFIG. 3, the feed mechanism comprises a push block22that is configured for translational movement in the feed channel18between an urging position and at least one retracted position. As used herein, the term “push block” refers to any type of structure or mechanism capable of applying a motive or urging force to the ink sticks in the channel to cause the ink sticks to move in the feed direction F of the channel. To provide the motive or urging force, the push block22is operatively connected to a drive system configured to move the push block22between an urging position and at least one retracted position. In the urging position, the push block22is moved into contact with a trailing end surface154of the column of ink sticks14in the feed channel by the drive system to apply a suitable force to the trailing end of the column of ink sticks to urge the ink sticks in the feed direction F so that the leading ink stick of the column impinges on the melt plate104. In the urging position, the push block22continues to apply the urging force to the column of ink as the leading ink stick is melted so that the next ink stick in the column is moved into contact with the melt plate104when the leading ink stick is completely melted. The melt device has been described as being associated with the ink loader such that only molten ink would be exiting the loader after being melted during normal operation. The melt end of the ink loader feed channel typically includes a melting assembly but the melt function may be a device not integrated with the ink loader. Descriptions of or similar to “melt end” are applicable to the ink loader and/or feed direction even when the melting means is independent or implemented in an arrangement other than as depicted inFIG. 3and otherwise described herein. One alternative example to the present configuration is a loader where the ink exit end is configured to direct solidified ink forms, which may be a small size, to another device where it would be melted, one example being a melt reservoir of a printhead.

In the embodiment ofFIG. 3, the urging force is provided by a constant force spring114which is wound at one end as a freely rotatable coil housed within the push block22. The coil may be wound about a hub116. The other end of the spring114is attached to a yoke118. The yoke118is configured to move adjacent to the feed channel18between a forward position J proximate the melt end100of the feed channel18and a rearward position K proximate the first end98of the feed channel. The yoke118may be supported for movement between the forward and rearward positions in any suitable manner. For example, in the embodiment ofFIG. 3, the yoke118is configured to cooperate with a guide slot and/or guide rail120arranged adjacent to the feed channel18to enable translational movement of the yoke118between the forward and rearward positions J,K, respectively. Yoke118motion is the push block22driver and the position of the push block is complementary to yoke position. The Yoke118influences the position of the push block22within the limits of its range of motion relative to spring loading influence and the presence of ink sticks within the feed channel. The reason for this will become apparent in the following description of push block functionality.

When the yoke118is in the forward position J, the constant force spring114pulls the push block22toward the melt end100of the channel to a location proximate the yoke118. If ink sticks are positioned in the feed channel18in front of the push block22, the pulling force of spring114on the push block22causes the push block22to move into contact with the trailing end of the ink sticks in the channel and urge the ink sticks toward the melt end100of the channel18. The spring114is coupled to the hub of the push block22in a manner that enables the spring body to extend between the yoke118and the push block22without interfering with ink stick movement in the feed channel. For example, as depicted inFIG. 3, the spring body extends along a path that is located above the feed path of ink sticks in the feed channel. In embodiments, the spring114may extend along a path to either lateral side of the feed channel or below the feed channel.

To enable the insertion of ink sticks into the channel18, the push block22is moved toward the insertion end98of the feed channel to a retracted position located beyond the insertion region30of the channel to enable ink sticks to be inserted into the feed channel in front of the push block (relative to the feed direction F). To move the push block22to the retracted position, the yoke118is moved from the forward position J to the rearward position K. When the yoke118is in its rearward position, the spring114coils within the push block22enabling the push block22to be moved by the yoke in the retraction direction R to its retracted position in the feed channel.

The yoke118is coupled to an actuation system124that is configured to move the yoke118between the forward and rearward positions J, K to enable ink loading operations. Any suitable type of actuation system may be used including manually operated actuation, electro-mechanical actuation, or a combination thereof. For example, in one embodiment, the yoke is coupled by a suitable linkage to a manually operated access cover that controls access to the insertion openings16of the ink loader. When the access cover is opened, the linkage122retracts the yoke118to its rearward position K which in turn causes the push block22to be retracted toward the first end98of the feed channel. When the access cover is closed, the linkage moves the yoke118to its forward position J thereby moving the push block22forward in the channel18and into the urging position. As an alternative to manually controlling yoke118position, some devices may include a motorized actuation system124configured to control the position of the yoke118to enable ink loading operations. A motorized actuation system124may be activated in any suitable manner such as by input received from the user interface78and/or by control signals received from the device controller70. In embodiments, the controller70may be configured to control the actuation system124to enable ink loading based on user input as well as other factors, such as device operating state.

During ink loading operations, if a previously loaded ink stick is located even partially in the insertion region30of the channel18, the insertion of an ink stick into the channel may be prevented. For example, depending on the position of the insertion region30in the channel, when multiple ink sticks are loaded into a channel and abutted against each other to form a column of ink, the column of ink may extend from the melt end100of the channel a distance such that the trailing end of the column protrudes into the insertion region30of the channel. To enable ink stick insertion in circumstances such as this, the feed channel18may be equipped with an ink stick retraction system200in accordance with one embodiment of the present disclosure. The ink stick retraction system200is configured to transport or move one or more ink sticks in the retraction direction R along the feed channel to a position between the first end98of the feed channel and the insertion region30in order to clear the insertion region30of the channel18for ink loading. This function enables numerous ink loader configurations, including insertion openings intermediate the ends of the feed channel and ink insertion “drawers” that can be pulled out from the main ink loader body to replenish ink. To enable clearance of the insertion region30by the retraction system200, the feed channel18includes a staging area or section218that extends between first end98of the channel and the trailing edge210of the insertion region that is sized to accommodate the desired number of retracted ink sticks and any push block or similar feed associated components.

As depicted inFIG. 3, the ink stick retraction system200includes an ink stick retractor204supported in the channel for translational movement along the feed channel between a forward position located between the melt end100of the channel and the leading edge214of the insertion region and a rearward position located between the first end98of the channel and the trailing edge210of the insertion region. The ink stick retractor204includes an ink stick engaging portion208that is configured to engage a portion of an ink stick at least during movement of retractor204in the retraction direction R from generally in and just ahead of the insertion region. In the embodiment ofFIGS. 3 and 4, the ink stick engaging portion is oriented at least partially perpendicular to the feed and retraction directions F, R in order to engage a portion of an ink stick14that faces generally toward the melt end100of the channel when the retractor204is moved in the retraction direction R. Ink sticks in the feed channel forward of the one or more ink sticks that can be pulled into a clearance area behind the insertion region are the only ink sticks that would be moved during retraction.

To facilitate reliable interaction between the ink stick engaging portion208of the retractor204and an ink stick14during retraction, ink sticks14may be provided with a motion control inset220. As depicted inFIGS. 2A,2B,3and4, the motion control inset220comprises a recess or pocket formed in the bottom surface160of the ink stick14. In the embodiment ofFIGS. 2A and 2B, the inset220is positioned proximate the trailing end of the ink stick14extending through the trailing surface154although an inset220may be provided at any suitable location to facilitate retraction. When an ink stick having an inset is positioned adjacent to another ink stick in the feed channel, the inset220forms a clear space between sticks for the ink stick engaging portion208of the retractor204to engage the leading surface156of an ink stick. The retractor204fits into the clearance area between surface156and surface224of inset220when the retractor is moved in the retraction direction R. In alternate configurations, an inset or pocket similar to220may be positioned at the ink stick front surface or intermediate the front and rear surfaces. With respect to the retractor, the leading surface is the leading surface of an interface engagement surface that may or may not be at the front of the ink stick.

The ink stick retractor204is coupled to a drive system that enables the retractor204to be controllably moved between the forward and rearward positions. In the embodiment ofFIG. 3, the ink stick retractor204is operatively connected to the push block22so that movement of the push block22controls the movement of the retractor204. The retractor204has an extended main body206that is operatively connected to the push block at one end210with the ink stick engaging portion208extending from the other end of the main body. The main body206extends from the push block22generally in the feed direction F of the feed channel18at a location that is at least partially outside of the area of the feed channel occupied by ink sticks. In the embodiment ofFIG. 3, the main body206of the retractor204is located substantially below the feed channel18although in alternative embodiments the main body206of the retractor204may extend along the lateral sides or above the occupied area of the feed channel.

The main body206positions the ink stick engaging portion208of the retractor204a suitable distance in front of the push block22to enable the ink stick engaging portion208to extend into the feed channel in front of at least a portion of an ink stick14located in front of the push block. The distance that the main body206extends from the push block22is selected based on the size and number of ink sticks that is required to be retracted in order to clear the insertion area30for a given feed channel configuration. Depending on the position of the insertion region30of the channel18relative to the ends98,100of the channel, one or multiple ink sticks may have to be retracted in order to clear the insertion area.

The main body206of the retractor may be connected to the push block in a manner that enables the main body206and the ink stick engaging portion thereof to move between a lowered position in which the ink stick engaging portion is located outside of the feed path of the feed channel and an elevated position in which the ink stick engaging portion208is located in the feed path of the feed channel. In the embodiment ofFIGS. 3 and 4, retractor204is connected to the push block in a manner that enables main body206of the retractor to flex or pivot with respect to the push block between lowered and elevated positions based on the direction of movement. In the exemplary embodiment, when the push block22is in the urging position, the ink stick engaging portion208of the retractor204is in the lowered position and spaced apart from the ink sticks14in the channel18. Movement of the push block22in the retraction direction R may cause the retractor204to pivot with respect to the push block22which causes the ink stick engaging portion208to move into the elevated position to engage an ink stick14in the feed channel18. Alternatively, the body206and engagement208of the retractor204may be configured to enable sufficient flexure to bend below and ride under an ink stick as the push block22is pulled forward in to contact. When the push block is fully against the one or more ink sticks being pushed, the retractor would rise to its nominal elevated position so that the engaging end204rises into the ink stick recess220, where it is positioned to enable retraction.

In other embodiments, the retractor204may be slidably coupled to the push block22so that full forward motion toward the melt end of the channel18is enabled. In the exemplary embodiment shown inFIGS. 4 and 5, the retractor204is slidably connected to the push block22for translational movement with respect to the push block in directions that are generally parallel to the feed and retraction directions F, R of the feed channel. The connection end228of the retractor204extends rearwardly past the front face of the push block22and is connected to a rearward facing portion of the push block22by a biasing member, such as a spring230. The spring biases the retractor in the feed direction F to enable the retraction of the desired number of ink sticks when the push block22and retractor204are moved in the retraction direction R. As depicted inFIG. 5, when the push block22approaches the melt end100of the channel18, the retractor204is contacted by an obstructing surface234that prevents further movement of the retractor204in the feed direction F thus preventing the retractor204from contacting the melt plate104. The biasing spring230enables the push block22to move with respect to the blocked retractor204and thus continue to move in the feed direction F and urge the ink stick14toward the melt plate104.

Referring now toFIGS. 6a-6d, another embodiment of an ink stick retraction system300is shown. The retraction system300ofFIGS. 6a-6dincludes a retractor304that is operatively connected to the yoke118of the ink loader rather than to a push block22. Similar to the embodiment ofFIGS. 3-5, the retractor304includes an ink stick engaging portion308that is configured to engage a portion of an ink stick at least during movement of the retractor304in the retraction direction R. The yoke118is located substantially above the feed channel18. The retractor304is pivotably connected to the yoke118to pivot between a clearance position (FIG. 6d) which in which the ink stick engaging portion308is spaced apart from the ink sticks in the channel and an engaged position (FIG. 6b) in which the ink stick engaging portion308is moved into the feed path to contact the surface of an ink stick in the feed channel (if present). As depicted, the retractor comprises a cantilever. In other embodiments, the retractor304may comprise a flexure or similar type of structure.

The retractor304is also configured to interact with a cam310that is configured to control the movement of the retractor304between the clearance and engaged positions based on the direction of movement and/or position of the yoke118relative to the feed channel. A spring314, or other suitable biasing structure, is positioned between the retractor304and the yoke to bias the retractor304toward the clearance position and into an intermediate, or neutral, position to facilitate engagement with the cam310.

As depicted inFIG. 6a, as the yoke118is moved in the retraction direction R, the retractor304engages the cam310which causes the retractor304to pivot from the neutral position (FIG. 6a) toward the engaged position (FIG. 6b). In the engaged position, the ink stick engaging portion308is moved into the feed path and into contact with an ink stick14. The retractor304pulls the engaged ink stick as the yoke118is moved in the retraction direction R. As depicted inFIG. 6b, movement of the retractor304to the engaged position compresses the spring314. At a predetermined location along the feed channel18, movement of the yoke118in the retraction direction causes the retractor304to move out of engagement with the cam310which allows the spring314to return the retractor304to the neutral position (FIG. 6c). As the yoke118is moved in the feed direction F, the retractor304engages the cam310. The neutral position of the retractor304as it is moved in the feed direction enables the cam310to pivot the retractor304into the clearance position (FIG. 6d).

FIGS. 6a-6ddepict one possible embodiment of a yoke mounted retractor. In alternative embodiments, a number of other suitable cam or cam track arrangements may be utilized. In addition, the retractor304may have a number of other configurations that enable the retractor to move ink sticks in the retraction direction with the movement of the yoke. The retractor304may comprise a flexure or cantilever or may be pivotally mounted to the yoke118so that the ink stick engaging portion308is located above the top surface of the ink sticks during movement of the yoke118in the feed direction F and is moved downwardly into the ink stick path of the feed channel18by a suitable feature, such as a cam or cam track interaction, to catch the top of an ink stick (not shown inFIG. 6) when the yoke118is moved in the retraction direction.

FIGS. 7a-7cdepict an embodiment of an ink stick retraction system400that is configured for movement independent of the feed mechanisms of the ink loader12. The system400includes a retractor404supported by a retractor drive system410that is configured to translate the retractor404between a forward position (FIG. 7a) and a rearward position (FIG. 7c) along the feed channel in the area of the insertion region30. The retractor404includes an ink stick engaging portion408that is moved into the feed channel to push, pull, or otherwise move ink sticks in the retraction direction R as the retractor404is driven from the forward position to the rearward position. Any suitable type of drive system may be used including electro-mechanical, pneumatic, hydraulic, linear motors, piezo motors and so forth.

In the embodiment ofFIG. 7, the drive system410comprises an electric motor412connected with or without a gear reduction to a drive wheel414acting on a looped drive belt418. The drive belt418operates a cam influenced translation system420to which the retractor404, in the form of a carriage or similar type of structure, is operatively connected. The cam system420causes the retractor404to translate in generally the feed and retraction directions F, R of the feed channel18. The retractor404includes an ink stick engaging member408comprising a cantilever spring arm that is held below the ink sticks in the feed channel when the retractor is in the forward position. When the drive system410is actuated for retraction, the cam system causes the retractor404to translate in the retraction direction R and simultaneously lift the ink stick engaging portion into the feed channel to engage and push any sick present in the insertion region30toward the first end98of the feed channel. The drive system410of the retraction system400ofFIG. 7may be actuated based on controller70influence so that the retraction operation takes place at the proper time in an ink loader load access cycle. In addition, a separate retraction system400may be provided for each feed channel18so that ink retraction and ink loading may occur independently for each color of ink. Many other mechanisms independent of the yoke or push block are possible, as example, smaller Ink stick sizes may allow a solenoid driven retractor actuation.