BACKGROUND
During the image forming process, toner is transferred from toner carrying members to print or copy media. Inefficiencies in the transfer process cause residual toner to remain on the toner carrying members or other transport members, such as transport belts, intermediate transfer belts/drums, and photoconductive members. Residual toner may also be created during registration, color calibration, paper jams, and over-print situations. This residual toner should be cleaned before it affects the quality of subsequent images. The residual or waste toner is commonly removed by a blade or other means and the removed toner is stored in a waste toner housing.
The effectiveness of a waste toner cleaner can be limited by back-pressure exerted at the cleaner throat by waste toner that accumulates in the housing. The cleaner throat is the area between a waste toner cleaner blade, a waste toner cleaner seal, and the surface being cleaned by the blade. Toner that is removed by the blade enters a waste toner cleaner housing at the throat. Back-pressure in this throat area may be generated by the sheer weight of the accumulated toner and may also be imparted through the accumulated toner pile by other devices in the housing, such as an auger that operates to move the waste toner to a location away from the cleaner blade. In any case, back pressure at the entrance to the housing can compromise the effectiveness of the cleaner by preventing newly cleaned waste toner from flowing into the cleaner housing.
SUMMARY
The present invention is directed to a cleaning apparatus applicable in a waste toner removal system for an image forming device. The invention includes a waste toner moving device that is movably mounted in a waste toner housing. The housing has an inlet where a cleaning blade is attached to remove toner from a transfer body. Waste toner that is removed by the blade enters the housing through the inlet. The waste toner housing includes an auger that rotates to move the toner within the housing. A drive gear is coupled to the auger to rotate the auger from a drive source. The toner moving device is pivotally mounted in the housing and is movable between a first position and a second position. The toner moving device is spring-biased toward the first position. A cam coupled to the gear displaces the toner moving device from the first position to the second position to move the toner in the housing away from the inlet and toward the auger. A portion of the toner moving device also contacts the auger when the toner moving device is in the first position. This contact between the toner moving device and the auger causes a vibration that inhibits the accumulation of toner on the toner moving device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a functional block diagram of an image forming apparatus according to one embodiment of the present invention;
FIG. 2 illustrates a side cross-sectional view of the waste toner cleaner according to one embodiment of the present invention;
FIG. 3 illustrates a side cross-sectional view of the waste toner cleaner according to one embodiment of the present invention;
FIG. 4 illustrates a perspective view of the waste toner cleaner according to one embodiment of the present invention;
FIG. 5 illustrates a partial detailed perspective view of the waste toner cleaner according to one embodiment of the present invention;
FIG. 6 is a partial side view and the first in a sequence showing the actuator movement according to one embodiment of the present invention;
FIG. 7 is a partial side view and the second in a sequence showing the actuator movement according to one embodiment of the present invention;
FIG. 8 is a partial side view and the last in a sequence showing the actuator movement according to one embodiment of the present invention; and
FIG. 9 is a detail view of the chopping wall of the toner moving member according to one embodiment of the present invention.
DETAILED DESCRIPTION
The present invention is directed to a cleaner apparatus for a waste toner system within an image forming device as generally illustrated in FIG. 1. FIG. 1 depicts a representative image forming device, indicated generally by the numeral 10. The image forming device 10 comprises a main media sheet stack 16. Media sheets may also be introduced through a manual input 20. The term “image forming device” and the like is used generally herein as a device that produces images on a media sheet. Examples include but are not limited to a laser printer, ink-jet printer, fax machine, copier, and a multi-functional machine. Examples of an image forming device include Model Nos. C750 and C752 available from Lexmark International, Inc. of Lexington, Ky.
Within the image forming apparatus body 12, the image forming apparatus 10 includes a plurality of removable image formation cartridges 26, each with a similar construction but distinguished by the toner color contained therein. In one embodiment, the apparatus 10 includes a black cartridge (K), a magenta cartridge (M), a cyan cartridge (C), and a yellow cartridge (Y). Each cartridge 26 forms an individual monocolor image that is combined in layered fashion with images from the other cartridges to create the final multi-colored image. The image forming apparatus further includes an intermediate transfer mechanism (ITM) belt 24, one or more imaging devices 30, a fuser 32, and a waste toner cleaner 40 as well as various rollers, actuators, sensors, optics, and electronics (not shown) as are conventionally known in the image forming apparatus arts, and which are not further explicated herein.
The internal components of removable image formation cartridges 26 are not specifically identified in FIG. 1, but are briefly described. Each image formation cartridge 26 is a removable cartridge that may include a reservoir holding a supply of toner, a developer roller for applying toner to develop a latent image on a photoconductive drum, and a photoconductive (PC) drum 14, which may comprise, for example, an aluminum hollow-core drum coated with one or more layers of light-sensitive organic photoconductive materials. The image formation cartridge 26 may additionally include various rollers, paddles, augers and blades, as well known in the art. Note that this description is representative only—various image formation devices may organize these components into a plurality of cartridges.
The operation of the image forming apparatus 10 is conventionally known. Upon command from control electronics, a single media sheet is “picked,” or selected, from either the primary media stack 16 or the manual input 20. Regardless of its source, the media sheet is transported to transfer location 22 to receive a toner image from the ITM belt 24. The ITM belt 24 is endless and rotates in the direction indicated by arrow R around a series of rollers adjacent to the PC drums 14 of the respective image formation cartridges 26. Toner is deposited from each PC drum 14 as needed to create a full color image on the ITM belt 24. The ITM belt 24 and each PC drum 14 are synchronized so that the toner from each PC drum 14 precisely aligns on the ITM belt during a single pass.
The media sheet may receive an electrostatic charge before contacting the ITM belt 24 at the transfer location 22 to assist in attracting the toner from the belt 24. The sheet and attached toner next travel through a fuser 32 having a pair of rollers and a heating element that heats and fuses the toner to the sheet. The paper with fused image is then transported out of the printer body 12 for receipt by a user.
In the image forming apparatus shown in FIG. 1, four image formation cartridges 26 are arrayed along the ITM belt 24. A full color image is formed on the ITM belt and the color image is subsequently transferred to a print media sheet at a secondary transfer location 22. Other devices may use an intermediate transfer drum instead of belt 24. In other conventional image forming devices, print media sheets are transported by a transfer belt similar in configuration to belt 24, but a full color image is formed directly on the media sheet by successively transferring images from the four respective image formation cartridges 26 (cyan, yellow, magenta, and optionally black) onto the media sheet. In either of these configurations, residual toner that remains on the belt 24 following the image formation process is removed by a waste toner cleaner 40. Residual toner that remains on belt 24 following color calibration and/or paper registration processes must also be cleaned by the waste toner cleaner 40.
FIGS. 2 and 3 illustrate a side cross-sectional view of the waste toner cleaner 40. The waste toner cleaner 40 is comprised of a blade 42, blade bracket 44, lower seal 46, auger 48, and cleaner apparatus 50 all contained within or coupled to a housing 52. The waste toner cleaner 40 is positioned so that cleaner blade 42 is in contact with a surface to be cleaned. The surface to be cleaned may be part of a number of different electrophotographic components, including intermediate transfer member belts, photoconductor belts, photoconductor drums, and media transport belts. In the orientation shown in FIGS. 2 and 3, the surface to be cleaned moves past the waste toner cleaner 40 at the inlet to the housing 58. As the surface to be cleaned moves past the waste toner cleaner 40, the cleaner blade 42 removes toner from that surface. The removed toner is guided at inlet 58 into the interior of the housing 52 by lower seal 46. The removed toner accumulates in the housing on floor 60, which is sloped gradually downward and rearward away from the inlet 58. The auger 48 rotates to transport the waste toner to a separate part of housing 52 or to a remote storage container (not shown). In the embodiments shown in the Figures, the auger 48 is depicted as a coiled wire, although other conveyors known to those skilled in the art, including screws or other equivalent devices, may be used. The auger 48 is rotatively driven by a gear 76 (see FIGS. 4 through 8) that is driven by an external drive source (not shown).
The cleaner apparatus 50 comprises a toner moving member 54 that is pivotally attached to the housing 52 at pivot point 56. The toner moving member 54 is depicted in FIG. 2 in a first position and is depicted in FIG. 3 in a second position. These positions are described in further detail below. The toner moving member 54 is a generally elongate structure (see also FIG. 4) that spans much of the width of the cleaner housing 52 and has a generally inverted-L shape cross section. The upper portion of the inverted-L shape is defined by a shelf 66, while the lower portion of the inverted-L shape is defined by a chopping wall 68. The chopping wall 68 may advantageously be subdivided into upper 68a and lower 68b sections. The toner moving member 54 is supported at its ends by side walls 62. Protrusions 64 extending from side walls 62 are engaged by corresponding pivot supports 72 located within the housing 52. In one embodiment, protrusions 64 are embodied as dowel pins that are inserted into holes in the side walls 62. In another embodiment, the protrusions 64 are an integral part of the toner moving member body 54. When supported in this manner, pivot point 56 coincides with the center axis of protrusions 64.
The toner moving member 54 is pivotable between two positions about pivot point 56. In FIG. 2, toner moving member 54 is in a first position where the leading edge 70 of the lower section 68b of chopping wall 68 is spaced away from the floor 60 of housing 52. By comparison, the toner moving member 54 shown in FIG. 3 is in a second position where the leading edge 70 of the lower section 68b of chopping wall 68 is closer to the floor 60 of housing 52. In one embodiment, the leading edge 70 actually contacts the floor 60 in the second position. In one embodiment, the leading edge 70 is adjacent to the floor 60 in the second position. In another embodiment, the leading edge 70 is spaced away from the floor 60 in the second position, but is still in closer proximity to the floor than in the first position. In one embodiment, the toner moving member 54 is biased by a spring 71 or other resilient member towards the first position.
Pivot point 56 is positioned vertically above the floor 60 of housing 52 so that as the toner moving member 54 travels between the first and second positions, the leading edge 70 is contactable with the floor 60. In one embodiment, the lower edges 74 of side walls 62 remain out of contact with the floor 60 so as not to impede the motion of the toner moving member 54. In one embodiment, the pivot point 56 is positioned at nearly the same vertical height as the leading edge 70 in the second position described above. In other embodiments, the position of pivot point 56 may advantageously be placed at higher points in space, as design constraints permit, to allow the leading edge 70 to pass a horizontal apex and travel away from the inlet 58 and away from blade 42 as the toner moving member 54 approaches the second position. In this latter configuration, the movement of the leading edge 70 will therefore have a horizontal component that will aid in moving waste toner away from the inlet 58 and towards the auger 48.
In addition to using the motion of the leading edge 70 (as just described) to displace waste toner within housing, the shape of the leading edge 70 and chopping wall 68 also advantageously cooperate to displace waste toner away from the blade 42. FIG. 9 shows a detail view of the orientation of the upper 68a and lower 68b sections of chopping wall 68 relative to the floor 60 of housing 52 when the toner moving member 54 is in the second position (as shown in FIG. 3). As shown in FIG. 9, the upper 68a and lower 68b sections of the chopping wall 68 are disposed at different angles relative to the floor 60 of housing 52, although both sections 68a, 68b are tilted away from the inlet 58 and blade 44. The lower section 68b is more acutely oriented than the upper section 68a relative to the floor 60. In other words, the lower section 68b is tilted at an angle Θ1 relative to floor 60 that is less than the angle Θ2 at which the upper section 68a is tilted. The orientation of the upper 68a and lower 68b sections aid in directing waste toner away from the inlet in generally the left to right direction in FIG. 9. Thus, the design of the chopping wall 68 moves the toner away from the blade 44 towards the auger 48 and advantageously prevents toner build-up that could cause back-pressure on the blade 44.
If the angle Θ1 is too small, the lower section 68b will compact waste toner against floor 60 instead of displacing the toner away from the inlet. If the angle Θ1 is too large, the waste toner will remain stagnant on the floor 60 and not move towards the auger 48. The angle Θ1 is selected to be in the range between about 25° and 65°. In one embodiment, the angle Θ1 is selected to be in the range between about 40° and 45°. In one specific embodiment, the angle Θ1 is selected to be 42°.
The angle Θ2 is less acute than Θ1 to inhibit adhesion of waste toner to the chopping wall 68. Thus, a more vertical orientation is desirable and the angle Θ2 is selected to be in the range between about 65° and 90°. In one embodiment, the angle Θ2 is selected to be in the range between about 75° and 80°. In one specific embodiment, the angle Θ2 is selected to be 77°.
In one embodiment, the chopping wall 68 does not have upper and lower sections 68a, 68b, but instead is comprised of a single flat section that is disposed at a fixed angle relative to the floor 60 of housing 52. In another embodiment, the chopping wall 68 is comprised of a curved wall that has a constant radius. In another embodiment, the chopping wall 68 is comprised of a curved wall that has a lower leading portion that is more acutely oriented than an upper portion. A variety of configurations for the chopping wall 68 that incorporate the teachings herein may be employed as will be understood by those skilled in the art.
Referring now to FIG. 4, a perspective view of the cleaner apparatus 50 is provided. As discussed above, the toner moving member 54 includes a reciprocating chopping wall 68 and upper shelf 66. The toner moving member is pivotable about protrusions 64 that extend from the side walls 62. FIG. 4 also shows the auger 48 as a spiraled body adapted to displace waste toner within or from the waste toner housing 52. The waste toner housing 52 and other components of the waste toner cleaner 40 (e.g., blade 44, seal 46) are omitted for clarity. The auger 48 is driven by a drive gear 76 that is rotated by a drive source that is not explicitly shown in the Figures, but is understood by those skilled in the art to be a motor and/or a drive train capable of imparting a rotational force to the waste toner auger 48. The drive gear 76 shown in FIGS. 4 through 8 rotates in a direction indicated by the arrow labeled R. This gear rotation, in turn, rotates the auger so as to displace toner in the direction indicated by the arrow labeled T.
As shown in FIGS. 3, 4, and 5, the upper shelf 66 of toner moving member 54 extends substantially perpendicular from the upper portion 68a of the chopping wall 68. The shelf 66 has a contact portion 66a that extends a larger distance away from the chopping wall 68 and towards auger 48 than the remainder of the shelf 66. Wall 78 shown in FIG. 5 represents the transition area between the contact portion 66a and the remainder of the shelf 66. The contact portion 66a advantageously protrudes a sufficient amount as to permit tabs 80 to contact auger 48. As discussed above, the toner moving member 54 is biased toward the first position where the chopping wall 68 is elevated from floor 60 of the waste toner cleaner housing 52. In this first position, the contact portion 66a of shelf 66 is placed close to the auger 48.
A plurality of triangular-shaped tabs 80 extend outward from the end of contact portion 66a of shelf 66. These tabs 80 extend farther towards the auger 48 than does the contact portion 66a. As a result of this protrusion, the individual turns (e.g., 48a and 48b shown in FIG. 5) of the auger 48 periodically come into contact with the tabs 80 as the auger rotates. As discussed above, the auger 48 tends to displace waste toner in the direction indicated by the arrow T. Consequently, the individual turns of the auger 48 also tend to move in this direction. The tabs 80 are generally triangle-shaped with the leading edge 82 (i.e., the edge closest to drive gear 76) having a more gradual slope than the trailing edge 84. As the auger 48 rotates, the individual auger turns 48a, 48b initially contact the tabs 80 at the leading edge 82. The motion of the auger 48 in sliding contact with the tabs 80 vibrates the toner moving member 54. The interference between the tabs 80 and the auger 48 also creates a small displacing force. This small displacing force tends to pivot the toner moving member 54 against the bias of spring 71 a small amount out of the first position in the direction of the second position. In essence, the auger 48 displaces the toner moving member by the tabs 80 until the individual auger turns 48a, 48b move past the tabs 80. Once the auger turns 48a, 48b come out of contact with the tabs 80, the toner moving member 54 returns to the first position under the influence of spring 71. The slope of the trailing edge 84 of tabs 80 is sharp to permit the auger 48 to quickly lose contact with the tabs 80 and allow the toner moving member 54 to rapidly return to the first position. This rapid movement imparts a jarring motion that tends to loosen any waste toner that may accumulate on the toner moving member 54. The jarring motion may also be of a sufficient magnitude to vibrate the remainder of the housing 52, housing blade 44, and lower seal 46 to loosen accumulated waste toner.
Referring still to FIGS. 4 and 5 with additional attention now to FIGS. 6 through 8, the drive gear 76 is coupled to the auger 48 by a shaft 86. For clarity, FIGS. 6–8 show only the drive mechanism that operates to deflect the waste toner cleaner apparatus 50 between the first (up) position and the second (down) position. The shaft 86 protrudes through the drive gear 76 and through the waste toner cleaner housing 52 so that the auger 48 can be driven by an external drive source (not shown). An actuator, depicted generally by the number 88, is also coupled to the shaft 86. In the embodiment shown in the Figures, actuator 88 is advantageously embodied as a cam 90 that has a single eccentric lobe 92 that causes the toner moving member 54 to deflect downward from the first position to the second position as described above. Once per revolution of shaft 86 (and hence, gear 76), the cam lobe 92 comes into contact and moves a deflecting arm 94 of pivot linkage, which is indicated generally by reference numeral 96. In one embodiment, the pivot linkage 96 is implemented as a bail, or a twisted wire member with the shape shown in the Figures. The pivot linkage 96 is mounted to the waste toner housing 52 at horizontal mounting segments 98 and 99. The cam lobe 92 contacts the deflecting arm 94, which causes the pivot linkage to pivot about horizontal segments 98, 99. As the deflecting arm 94 pivots, a lower urging segment 100 pivots about horizontal segments 98, 99 in the same rotational direction as the deflecting arm 94.
The lower urging segment 100 rests within a channel 102 in the toner moving member 54 that is bounded on opposite sides by walls 104, 106. As the deflecting arm is moved by cam lobe 92, the urging segment 100 tends to push on wall 106. The point of contact between urging segment 100 and wall 106 is above pivot point 56. Consequently, toner moving member 54 rotates in a direction indicated by the arrow D shown in FIG. 6. As cam 90 continues to rotate while contacting the deflecting arm 94, the pivot linkage 96 continues to rotate about horizontal segments 98, 99. FIG. 7 shows the cleaner apparatus 50, including toner moving member 54 and pivot linkage 96 rotated into the second, downward position described above. As the cam 90 continues to rotate out of contact with the deflecting arm 94 as shown in FIG. 8, the bias spring 71 (not shown in FIGS. 6–8) tends to return the cleaner apparatus 50 to the first position. In this manner, the toner moving member 54 deflects between the first and second positions to displace toner along the waste toner housing floor 60.
In one embodiment, the pivot linkage 96 is a resilient drive bail that is rigid enough to impart the urging forces described. However, the resilient nature of the pivot linkage 96 tends to buffer impact forces that may otherwise be transmitted to the toner moving member 54 by the actuator 88. Design constraints will invariably determine the shape and configuration of the actuator 88, drive linkage 96, and toner moving member 54. Thus, the design shown in the Figures is one particular embodiment. Other designs may capture the essence of the teachings herein. For instance, in one embodiment, it may be desirable to have the actuator 88 directly contact the toner moving member 54 in order to deflect the toner moving member 54 between the first and second positions. In addition, a spring 71 has been shown in FIGS. 2 and 3 as providing a biasing force tending to hold the waste toner cleaner apparatus 50 in the first position. In another embodiment, a separate spring may be used to bias the drive linkage 96. Furthermore, a cam actuator 90 has been shown as providing the initiation force that drives the cleaner apparatus 50 toward the second position. In other embodiments, a cam with multiple lobes or a rotating body with one or more recesses may be used to provide the impetus that deflects the cleaner apparatus 50 as described. Alternatively, the cleaner apparatus 50 may be spring biased toward the second position while an actuator permits periodic transitions to the first position.
The present invention may be carried out in other specific ways than those herein set forth without departing from the scope and essential characteristics of the invention. For instance, the embodiments described have been depicted in use with a waste toner cleaner 40 that uses a blade 44. Other cleaners known by those skilled in the art, such as foam or brush rollers can also be employed. Furthermore, while the embodiments discussed have been described in the context of a waste toner mover 54 that pivots about point 56, may be desirable to implement a linearly actuating waste toner mover. The waste toner mover 54 may be incorporated in a variety of image forming devices including, for example, printers, fax machines, copiers, and multi-functional machines including vertical and horizontal architectures as are known in the art of electrophotographic reproduction. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
Patent Grant
7043189
