Patent Grant
8622532
The presently disclosed embodiments relate to delivery of solid-ink pellets to an image-forming apparatus, and more particularly to devices that maintain flowability of solid-ink pellets during delivery.
An image-forming apparatus employing solid-ink pellets, such as a printer, a fax machine, or a photocopier, includes a system for extracting pellets from a container for delivery to the image-forming apparatus. Conventionally, the solid ink pellets are placed in a container, and a feeding mechanism extracts the pellets and transports them to a heater assembly. There, the heater melts the pellets and a feeding mechanism applies the resulting liquid to media to form images.
In general, solid-ink pellets are stored in a container, from which pellets are extracted for print production as required. Typically, an extraction tube is inserted into the container, suction is applied to the extraction tube, and the resulting airflow entrains the solid-ink pellets from an extraction inlet in the extraction tube.
A flow problem can arise, however, when pellets bridge or clump together. This process, known as agglomeration, can occur when the pellets are stored in the container, as adjacent particles tend to fuse together under the combined action of temperature and pressure. Also, static charges on individual particles can cause attraction between adjacent particles, leading to agglomerations. Further, the prilling process employed to manufacture the solid-ink pellets can result in the pellets being brought into close proximity before they have cooled, likewise leading to agglomerations. The resulting clumps or agglomerations may exceed the size of the extraction inlet, clogging the flow of the solid-ink pellets.
Known approaches to this problem aim to break up the bridges and clumps, employing a variety of mechanical means. Generally, these solutions adapt the extraction tube to provide a device that manually agitates the solid-ink pellets to break up the agglomerations. This manual agitation must be performed sufficiently often to maintain the desired flow of solid-ink pellets. Where a number of agglomerations have formed, significant operator intervention may be required. Moreover, the agitation process itself interrupts pellet movement, and it often fails to produce the pellet movement once clumps have clogged the system.
In general, containers store considerable volumes of solid-ink pellets, and manually agitating the container may be cumbersome. In another alternative solution, mixers or grinders are coupled to the container to break obstructions. Current solutions, however, limit the breakage of agglomerates to positions near the extraction tube, thereby reducing both the efficiency of the breakage mechanism as well as the flowability of the solid-ink pellets.
It would be highly desirable to have a simple and cost-effective system that identifies an appropriate time for agitating pellet agglomerations, and further maintains flowability of solid ink-pellets from a container, breaking up clumps and agglomerates.
One embodiment of the present disclosure provides an apparatus for maintaining flowability of solid-ink pellets during suction-induced flow from a container to an image-forming device. The apparatus employs an extraction tube attached to a vacuum source, with an end of the extraction tube being inserted into the container for receiving pellets. Further, the apparatus includes a clog detector for sensing changes in vacuum level within the extraction tube to identify clogging. Based on the identification of the pellet agglomerations, an agitating structure breaks up pellet agglomerations
Another embodiment of the present disclosure provides an apparatus for maintaining flowability of solid-ink pellets during suction-induced flow from a container to an image-forming device, employing a clog detector. The apparatus employs an extraction tube attached to a vacuum source, with an end of the extraction tube being inserted into the container for receiving pellets. Further, the apparatus includes a clog detector for sensing changes in vacuum level within the extraction tube to identify clogging.
A further embodiment of the present disclosure provides an apparatus for maintaining flowability of solid-ink pellets during suction-induced flow from a container to an image-forming device, incorporating apparatus to break up pellet agglomerations. The apparatus employs an extraction tube attached to a vacuum source, with an end of the extraction tube being inserted into the container for receiving pellets. Further, the apparatus includes an agitating structure to break up pellet agglomerations
Another embodiment discloses a method for maintaining flowability of solid-ink pellets during flow from a container to an image-forming device. The method involves inducing a suction force through an extraction tube for pellet extraction. The method further involves transporting the pellets from the container to an assist tube, through inlet holes of the assist tube, the assist tube being inside the container. In addition, the method includes detection of clogging, followed by agitation of the pellet agglomerations to undergo breakage. Pellets are transferred from the assist tube to the image-forming device through the extraction tube.
The following detailed description is made with reference to the figures. Preferred embodiments are described to illustrate the disclosure, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations in the description that follows.
As used herein, the term “tube” includes any generally elongated device enclosing a lengthwise passage, suitable for conveying fluid or particulates. As thus defined, a tube may be formed of any suitable material and in any suitable cross-section.
Overview
The present disclosure describes various embodiments of a system and a method for maintaining flowability of solid-ink pellets during delivery to an image-forming device. The solid-ink pellets are stored in a container, and an extraction tube extends into the container for receiving the pellets. One end of the tube extends to the vicinity of the container bottom and the other end extends at least above the top, or lid, of the container. A vacuum source applies suction to the end of the vacuum tube to produce an airflow through the tube, entraining pellets in the airflow and moving them to the image-forming device. In the event that obstructions interfere with the smooth flow of pellets, a clog detector connected to the extraction tube senses a pressure spike. The system then activates an agitating structure, which can take any of a number of alternative constructions. The resulting agitation breaks up the pellet agglomerations to eliminate clogging, and airflow resumes, restoring a smooth extraction of pellets from the container.
Conventional Delivery System
Extraction assembly 105 provides a path by which solid-ink pellets 104 can flow from container 102, and it includes an assist tube 106 and an extraction tube 112. Assist tube 106 is generally rigid and tubular, having an open end 106a, a closed end 106b, and a number of inlet holes 108 passing through the sides of assist tube 106 near closed end 106b. This structure stands vertically in container 102, supported either by a convenient structure (not shown), such as struts, extending to the sides of container 102, or by an opening formed in a lid or cover (not shown) provided atop container 102. As shown, assist tube 106 extends to the vicinity of container 102 bottom. Extraction tube 112 is carried within assist tube 106, with an extraction inlet 116 at the tip of extraction tube 112, extending to the vicinity of closed end 106b. The portion of this tube lying within assist tube 106 is generally rigid, and it is carried within assist tube 106, supported by convenient means (not shown). The sizing of assist tube 106, extraction tube 112, and inlet holes 108 is based on the sizing of solid-ink pellets 104, as discussed below. It should be noted that the extraction inlet 116 of the illustrated embodiment is defined by the tip of the extraction tube, but that inlet can be formed as desired in the extraction tube, based on the need to provide a convenient and effective entrance for the pellets to enter the extraction tube.
Delivery assembly 117 provides both the motive means and the destination for the flow of solid-ink pellets. Components of delivery assembly 117 include a vacuum source 114 and a melter 118. Vacuum source 114 is a source of suction, such as an air pump, connected to a downstream end 109 of extraction tube 112. A similar tube 119 extends from vacuum source 114 to melter 118, the latter being a conventional component of imaging devices employing solid-ink pellets.
In operation, vacuum source 114 applies suction to extraction tube 112, inducing a longitudinal airflow 120 in assist tube 106. This flow produces suction at inlet holes 108, impelling individual pellets 104 to become entrained in airflow 120 within extraction tube 112. Pellets 104 proceed to vacuum source 114 and on to melter 118.
For purposes of description, the present disclosure is described in connection with solid-ink pellets. Those skilled in the art, however, will appreciate that other environments may similarly require delivery of solid-ink pellets for printing or other purposes, from a storage container or similar device. The technology set out here can also be employed to promote flowability of solid particulates and pellets in a variety of other environments.
That delivery system encounters difficulties when solid-ink pellets 104 have agglomerated, as described above. Then, the agglomerations (also referred to as clumps, arches, or bridges) either cannot pass through inlet holes 108 or they cannot enter extraction inlet 116, depending on the size of the agglomerations. Experience has shown that the most likely clogging point is extraction inlet 116.
Exemplary Embodiments
In adapting the structure of
Clog detector 202 identifies clogging within extraction tube 112 by sensing pressure changes. Thus, input to clog detector 202 is a pressure line 205 connected to extraction tube 112 at some point above assist tube 106, but upstream of vacuum source 114. The output of clog detector 202 is some indication that a clog exists, which can be provided by any known means, such as an indicator light 203 or the automated means discussed below. Those of skill in the art will appreciate that a wide range of conventional and readily available devices can be employed to provide clog detector 202. Primarily, the device must be able to sense changes in pressure and indicate that fact. Thus, suitable devices would include a pressure switch or a vacuum switch, all well within the knowledge of those in the art.
Clog detector 202 operates by sensing the pressure spike that normally accompanies a blockage. During normal operation, vacuum pressure within extraction tube 112 remains relatively constant. Solid-ink pellets 104 flow smoothly into assist tube 106, where they become entrained in airflow 120 and proceed through extraction tube 112. If agglomerate forms near extraction inlet 116, however, vacuum pressure within extraction tube 112 immediately spikes, in a manner directly analogous to blocking the entry nozzle of a home vacuum cleaner. Clog detector 202 senses that condition and communicates it to the operator by illuminating indicator light 203.
As will be appreciated by those in the art, clog detector 202 can be any device that responds to events that accompany a clog. As noted, a pressure sensor or vacuum switch performs these functions and are clear choices for this component. Devices that sense airflow would also suffice, given that a decreasing airflow occurs following a clog. The latter class of devices is generally more expensive than simple pressure sensors, but airflow monitors may be preferred in certain situations. Of the devices, now known or hereafter developed, as known to those in the art can be substituted as desired.
Alternatives and variations of the disclosed structure will be apparent to those of skill in the art. On the macro scale, it will be recognized that the principles of the present disclosure apply generally to systems in which pelletized solids or particulates must be delivered from one point to another. Similarly, the material, construction, and sizing of disclosed components may be varied as desired to suit particular applications.
System 200 improves upon the operation of the conventional device of
In the embodiments described above, both assist tube 106 and extraction tube 112 were generally stationary within container 102. Here, however, extraction tube 112 is mounted on spring mechanism 312, and an upstream tube 313 extends from spring mechanism 312 to vacuum source 114 (not shown). Spring mechanism 312 is widely known in the art, consisting of a lower portion attached to extraction tube 112 and an upper portion attached to upstream tube 313. The lower and upper portions of spring mechanism 312 can slide longitudinally with respect to each other, lengthening or shortening the distance between them. A coil spring 302 separates the two portions, biasing them in a relatively open position. By adding spring mechanism 312, extraction tube 112 can move vertically within assist tube 106.
Movement of spring mechanism 312 is accomplished by actuator 304, operating through a linkage 306. Actuator 304 applies force to the upper portion of spring mechanism 312 to move it downward, together with extraction tube 112, and it releases that pressure to allow coil spring 302 to return extraction tube 112 to its starting position. Those of skill in the art will recognize a number of well-known devices can embody actuator 304. One embodiment may employ a stepper motor for this purpose, for example. Likewise, linkage 306 can employ a suitable mechanical construction to convert rotary output of actuator 304 to a reciprocal vertical motion. An embodiment for accomplishing that result may employ a cam connected to a pivoted arm to accomplish that result. Numerous variations on these particular components will be apparent to those in the art.
Agitating structure 300 operates in a generally automatic manner, requiring notification from clog detector 202 to actuator 304 that agitation is required. That result can be accomplished through a number of means, most readily by a signal connection 305. As desired for various applications, clog detector 202 may directly provide an operating signal to actuator 304, or suitable control means may be provided. Those devices lie within the skill of those in the art.
Agitating structure 300 begins operation with the detection of a clog, typically an agglomeration 315 lodged at extraction inlet 116. As discussed above, that situation produces a pressure spike within extraction tube 112 and upstream tube 313, triggering a detection event at clog detector 202. Here, clog detector 202 reacts to the detection event by signaling actuator 304 via signal connection 305. In turn, actuator 304 operates through linkage 306 to apply a downward force to the upper portion of spring mechanism 312, driving extraction tube 112 toward closed end 106b. That action results in extraction tube 112 pressing against agglomeration 315, breaking it into individual solid-ink pellets 104. Continued operation of actuator 304 produces a release of pressure on the upper portion of spring mechanism 312, so that the restoring force of coil spring 302 returns that mechanism to its fully open position, retracting extraction tube 112 as well. In the illustrated embodiment, clog detector 202 continues to signal actuator 304 as long as a clog remains, and during that time, actuator 304 and linkage 306 impart a reciprocal vertical motion to spring mechanism 312. When the clog is cleared, clog detector 202 stops signaling and actuator 304 ceases operation.
It should be clear to those in the art that a number of variations and alternative embodiments can be introduced into agitating structure 300 to cope with a varied assortment of particular situations. For example, depending upon the exact consistency of solid-ink pellets 104, the distance between the low cycle point of extraction tube 112 and closed end 106b can be varied so that extraction tube 112 impresses more or less pressure on agglomeration 315. Similarly, both the speed and operating force applied by actuator 304 can be varied as desired.
As shown, agitating structure 300 operates automatically, but manual operation can be provided if desired. For a manual system, a suitable device for signaling an operator, such as indicator light 203 shown in
Agitating structure 400 operates to clear clogs through the actions of brush 402 mounted at the tip of extraction tube 112, near extraction inlet 116. In the illustrated embodiment, brush 402 consists of a number of bristles extending generally perpendicular to extraction tube 112, of sufficient length to engage the inner sidewalls of assist tube 106. Brush 402 lies generally level with inlet holes 108, so that the bristles engage inlet holes 108. Only one set of bristles appears in
Agitating structure 400 operates in a manner similar to structures discussed above. Upon clog identification, clog detector 202 signals actuator 404 via line 405 to initiate agitation of pellet agglomerations blocking inlet holes 108. Actuator 404 , acting through linkage 406, starts rotation of extraction tube 112, which in turn causes brush 402 to rotate within assist tube 106. Brush 402 wipes the inner surface of assist tube 106 including inlet holes 108, breaking any pellet agglomerations blocking inlet holes 108. It should be understood that at any instant during the circular motion, sets of bristles of brush 402 may only block one inlet hole, leaving remaining holes open. Alternatively, if brush 402 is substantially narrower than the width of inlet holes 108, all four inlet holes may be open at any instant to receive stored pellets. Actuator 404 may rotate extraction tube 112 continuously, at a predetermined time interval, or on agglomerate identification. In addition, actuator 404 and linkage 406 may be configured to provide reciprocal rotary movement, restricted in extent so that the bristles of brush 402 remain inserted into inlet holes 108.
The embodiments discussed in connection with
Agitating structure 500 employs a set of wires to break up agglomerations near inlet holes 108 and extraction inlet 116. As shown in
It can be noted from inspection of
Wires 502 can be attached to extraction tube 112 using a number of conventional devices, such as a span fit attachment, a friction joint, or other suitable attachment means. For a span fit attachment, wires 502 are connected to a ring-shaped structure 505, as shown in
The extent of both vertical and rotary movement provided by actuator 503 and linkage 509 is carefully regulated in this embodiment to avoid damaging wires 502. Those in the art will understand suitable methods for controlling actuator 503 to accomplish that result. Alternatively, mechanisms such as wave washer 506, discussed above, may be employed to prevent damage to wires 502 in the event of over rotation.
Operation of agitating structure 500 proceeds in a fashion similar to that previously discussed. Upon identifying a clog, clog detector 202 signals actuator 503 via line 507 to initiate motion of extraction tube 112. Based on the exact type and extent of motion desired, as reflected in configuration of the embodiment, actuator 503 and linkage 509 cooperate to produce a desired degree and tempo of reciprocal rotary or vertical motion, or a combination of the two. This motion is restricted to an extent that precludes wires 502 from making contact with the sides of inlet holes 108. The reciprocating motion causes wires 502 to move across inlet holes 108, breaking up agglomerations and clearing any flow barriers.
Agitating structure 600 breaks up agglomerations in the vicinity of inlet holes 108 through the action of a set of wires 602. As shown, the two wires 602 are mounted at the bottom of extraction tube 112 and extend outward through inlet holes 108. The two wires 602 meet at a crossover point 606, with no rigid connection between the two. In general, wires 602 are substantially thin wires such that they do not restrict the flow of pellets 104 from inlet holes 108.
To prevent wires 602 from slipping out of assist tube 106, a retention mechanism may be employed. As shown in
Agitating structure 600 operates in a manner similar to the embodiments previously discussed. Once a clog is identified, clog detector 202 directs actuator 601, through a signal line 605, to initiate rotation of assist tube 106. Rotation proceeds through the action of actuator 601 through linkage 609, which reciprocally rotates assist tube 106 about a pivot point 603. That movement causes wires 602 to move back and forth within inlet holes 108, breaking up any agglomerations near inlet holes 108. Breaking up clogs allows smooth passage of pellets 104 entering through inlet holes 108.
In the illustrated embodiments of system 200, the width of inlet holes 108 depends on the size of solid-ink pellets 104, which is typically about 2 mm. In general, inlet holes 108 are structured with a clearance greater than the size of solid-ink pellets 104 in order to allow transportation of pellets 104. Thus, the slots of the illustrated embodiment have a width of about 8 mm.
As can be seen, the agitating structures or systems described in various embodiments (
The geometry and the movement of the agitating structures may depend on the properties of the particular solid-ink pellets 104 employed in a given implementation. Relevant parameters can include bulk density, size range, melting point, static charge, flowability and so on. Further, assist tube 106 and extraction tube 112 can be tailored to these properties; for example, the diameter of extraction tube 112 may be based on the size range of solid-ink pellets 104 being extracted.
It will be apparent to those of skill in the art that a number of structural variations can be introduced to agitate and break up agglomerations. For example, the actuator (described in various embodiments) may be operatively coupled to the agitating structure (such as wires, brushes, or the like) but not to extraction tube 112, so that the actuator only rotates the agitating structure. Alternatively, multiple agitating structures may be introduced in container 102, all driven by an actuator. Further, the agitating structure may only include a brush or wires to break up pellet agglomerations.
In addition, actuators 304, 404, and 503 are disclosed as being individually connected to extraction tube 112; it should be apparent, however, that these actuators may be a part of the image-forming device or container 102 and may be detachably connected to extraction tube 112. The actuators may include a drive motor or an air cylinder. The process of introducing vertical and/or rotary movement in a structure, such as extraction tube 112, using an actuator is known to those skilled in the art and is not explained in detail. In the illustrated embodiments, the actuators may substantially move the actuator arm about the longitudinal axis and/or about the circumference of extraction tube 112, breaking up the flow barriers with minimum torque. A torque value of 5 N-m generated by the actuators may be sufficient to break up the pellet agglomerations.
Additionally, those in the art will understand that embodiments of the present disclosure will be suitable for performing agitation and clog detection functions in implementations that deal with any manner of pelletized, pellet-like, or particulate matter. The particular details of clog detection and mitigation will differ for each environment, but those of skill in the art will understand the specific variations required in each situation.
Pellets 104 in the vicinity of inlet holes 108 may have agglomerated into clumps or agglomerations, owing to the processes discussed above. Where, as shown in
After detecting a clog, the system proceeds to step 706, where it begins to employ an agitating structure to break up the agglomerations. Specific examples of agitating structures are described in
As explained above, a variety of devices can embody the processes of detecting clogs and mitigating their effects. Moreover, the specific steps employed in such processes may vary in order of timing, or exact manner of implementation. Those of skill in the art will understand effective techniques adapted to particular situations.
It should be noted that the description below does not set out specific details of manufacture or design of the various components. Those of skill in the art are familiar with such details, and unless departures from those techniques are set out, techniques, designs and materials known in the art should be employed. Those in the art are capable of choosing suitable manufacturing and design details.
The terminology used herein describes particular embodiments only; considerable variation is anticipated in implementation. It will be appreciated that several of the disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 4943818 | Hotomi | Jul 1990 | A |
| Number | Date | Country |
|---|---|---|
| 401171905 | Jul 1989 | JP |
| Number | Date | Country | |
|---|---|---|---|
| 20120287210 A1 | Nov 2012 | US |
