Patent Application
20080226351
The present application is directed to devices and methods for moving toner and, more specifically, to a weighted toner paddle for distributing toner within a reservoir of an image forming device.
Image forming devices including copiers, laser printers, facsimile machines, and the like, include a photoconductive member that receives toner during the image formation process. The toner is stored in a reservoir adjacent to the drum and is transferred to the drum's photoconductive surface through a nip point between a nip blade and developer roller. The toner image is then transferred directly or indirectly through an intermediate member to a media sheet, such as a blank sheet of paper. The media sheet is then heated thereby permanently fusing the toner to the sheet.
Toner cartridges may be replaceable to allow a user to input new toner into the image forming device after a first amount of toner originally within the device has been depleted. The toner cartridges are positioned within the image forming device at locations that provide convenient access to a user. The image forming device includes mechanisms for moving the newly-introduced toner from the new cartridge to the photoconductive drum.
The image forming device and toner cartridges should be designed to produce an overall product having the smallest possible dimensions. This may be a key selling point to consumers who desire the small dimensions because the devices are easier to manipulate and move, and occupy a minimal amount of space in a workstation where available space if often at a premium.
The present application is directed to devices for moving toner within an image forming device. In one embodiment, the device includes a reservoir with an inlet that leads into the reservoir through a first sidewall. New toner may be introduced through the inlet and into the reservoir. A paddle, may be positioned within the reservoir to move the toner from the inlet and through the reservoir. The paddle may prevent the toner from accumulating at the inlet which may act as a block to prevent further toner from being moved into the reservoir. The paddle may include a shaft with a weighted first arm extending from the shaft in a first direction and a second arm extending from the shaft in a second direction. The arms are weighted such that the first arm is heavier than the second arm. The paddle is positioned within the reservoir such that rotation of the paddle moves the toner from the inlet throughout the reservoir.
The present application is directed to toner paddle positioned to move toner within a reservoir. The reservoir includes an inlet for receiving new toner. The toner paddle includes a weighted arm and is positioned to move the toner from the inlet and throughout the reservoir
A first toner transfer area 160 includes an imaging unit with one or more imaging stations 10. The imaging stations 10 are aligned horizontally extending from the front 110 to the back 111 of the body 101. Each imaging station 10 includes a developer unit 18, a photoconductor unit 19, and a toner cartridge 50. Each of the imaging units 10 is mounted such that photoconductive (PC) drums 122 are substantially parallel. For purposes of clarity, the units 18, 19, and cartridge 50 are labeled on only one of the imaging stations 10. In one embodiment, each of the imaging stations 10 is substantially the same except for the color of toner.
The developer unit 18 includes a toner reservoir 20 to contain the toner, a toner adder roll 23, and a developer roll 24, A paddle 11 is positioned within the reservoir 20 to move the toner. The photoconductor unit 19 includes a charging roll 129 and a PC drum 122.
The charging roll 129 forms a nip with the PC drum 122, and charges the surface of the PC drum 122 to a specified voltage such as −1000 volts, for example. A laser beam from a printhead 139 is directed to the surface of the PC drum 122 and discharges those areas it contacts to form a latent image. In one embodiment, areas on the PC drum 122 illuminated by the laser beam are discharged to approximately 300 volts. The developer roll 24, which also forms a nip with the PC drum 122, then transfers toner to the PC drum 122 to form a toner image. The toner is attracted to the areas of the PC drum 122 surface discharged by the laser beam from the printhead 139.
An intermediate transfer mechanism (ITM) 138 is disposed adjacent to each of the imaging stations 10. In this embodiment, the ITM 138 is formed as an endless belt trained about support roll 131, tension roll 132 and back-up roll 133. During image forming operations, the ITM 138 moves past the imaging stations 110 in a clockwise direction as viewed in
The ITM 138 rotates and collects the one or more toner images from the imaging stations 10 and then conveys the toner images to a media sheet at a second transfer area. The second transfer area includes a second transfer nip 140 formed between the back-up roll 133 and a second transfer roll 141.
A media path 144 extends through the device 100 for moving the media sheets through the imaging process. Media sheets are initially stored in the input tray 130 or introduced into the body 101 through a manual feed 148. The sheets in the input tray 130 are picked by a pick mechanism 143 and moved into the media path 144, In this embodiment, the pick mechanism 143 includes a roll positioned at the end of a pivoting arm. The roll rotates to move the media sheets from input tray 130 towards the second transfer area. In one embodiment, the pick mechanism 143 is positioned in proximity (i.e., less than a length of a media sheet) to the second transfer area with the pick mechanism 143 moving the media sheets directly from the input tray 130 into the second transfer nip 140. For sheets entering through the manual feed 148, one or more rolls are positioned to move the sheet into the second transfer nip 140.
The media sheet receives the toner image from the ITM 138 as it moves through the second transfer nip 140. The media sheets with toner images are then moved along the media path 144 and into a fuser area 150. Fuser area 150 includes fusing rolls or belts 151 that form a nip to adhere the toner image to the media sheet. The fused media sheets then pass through exit rolls 145 that are located downstream from the fuser area 150. Exit rolls 145 may be rotated in either forward or reverse directions. In a forward direction the exit rolls 145 move the media sheet from the media path 144 to an output area 147. In a reverse direction, the exit rolls 145 move the media sheet into a duplex path 146 for image formation on a second side of the media sheet.
In one embodiment, the developer unit 18 and the photoconductive unit 19 are separate members that are connected together as a single unit. One or more springs (not illustrated) may be positioned to maintain the developer roll 24 of the developer unit 18 in contact with the PC drum 122 in the photoconductor unit 19.
In one embodiment as illustrated in
The imaging unit 10 that includes one or more developer units 18 photoconductor units 19, and toner cartridges 50 may be positioned within a frame 80 within the body 101 of the image forming device 100 as illustrated in
The toner introduced into the developer unit 18 should be distributed through the reservoir 20. The distribution is further complicated because the inlet 21 may be positioned at an end of the reservoir 20. Further, the developer units 18 are positioned within the body 101 of the image forming device 100 with the reservoir 20 being substantially level. Therefore, gravity cannot be used to move the toner from the inlet 21 and laterally throughout the reservoir 20. The paddle 11 functions to move the toner laterally along the length of the reservoir 20.
Paddle 11 includes at least one weighted arm 12 that extends outward from a shaft 14.
In the embodiment of
The weighted arm 12 is heavier than the second arm 13 thus allowing the paddle to free-all during a rotation as will be explained below. The weight difference between the arms 12, 13 may vary depending upon the application.
As illustrated in
In addition to moving the toner within the reservoir 20, paddle 11 may also function as a toner sensor,
As illustrated in
When the developer unit 18 is mounted within the image forming device 10, the drive gear 80 is driven by a gear (not illustrated) attached to the developer unit 18. The paddle 11 and cam 60 are connected together to rotate at the same speed and orientation. Both are freely rotated by the drive gear 80 defined as providing a rotational force for moving the paddle 11 and cam 60 from a toner contact point to a release point at an upper portion of the paddle envelope. However, both the paddle 11 and cam 60 may rotate at a faster speed during an angular displacement portion of the revolution from the release point to the toner contact point due to the offset weighting of the paddle 11. By way of example, when the paddle 11 positioned at an upper position within the revolution, the offset weighting of the paddle 1 provides for the paddle 11 and cam 60 to freely rotate ahead or fall forward of the drive gear 80 until the paddle 11, and specifically the weighted arm 12, contacts the toner within the reservoir 20. At the point of contact with the toner both the cam 60 and the paddle 11 will lie substantially motionless until the drive gear 80 rotates to the position, or “catches up”. At this points the continuously rotating drive gear 80 will provide a force to rotate the paddle 11 and cam 60 through the remainder of the envelope.
In one embodiment, the release point is at the top-dead-enter point of the envelope; however, other release positions on the revolution may also be used for determining the angular rotation of the paddle 11. As the drive gear 80 catches up” to the cam mechanism 60, the pawl 70 is reset to the initial position. This process is continued for each revolution of the paddle 11 and cam 60.
The drive gear 80 continuously rotates due to the intermeshing of the teeth 81 with a corresponding gear within the body 101 of the image forming device 100. This rotation pushes the paddle 11 and cam 60 through continuous revolutions with the paddle 11 and cam 60 falling in front of the rotation of the drive gear 80 until the weighted arm 12 of the paddle 11 contacts the toner within the reservoir 20. Once the paddle 1 stops falling, the drive gear 80 catches up to the paddle 11 and cam 60 and rotates through the complete revolution. As the cam 60 rotates ahead of the drive gear 80, the cam profile 61 pushes the pawl boss 73 radially inward. This movement results in the elongated openings 72 sliding along the posts 82 and pawl extension 71 moving radially outward from the center of the pawl. The larger the angular displacement of the paddle 11, from the release point to the toner contact point, the further the cam 60 and cam profile 61 pushes pawl extension 71 radially outward. The movement of the pawl 70 is dictated by the dimensions of the cam profile 61. In one embodiment, the pawl 70 begins to radially move outward upon any angular displacement of the paddle 11 ahead of the drive gear 80. At an angular displacement of about 120 degrees relative to release, point, the pawl displacement is maximized. In other embodiments, the amount of movement of the pawl 70 and degree of angular displacement can be adjusted depending upon the specific parameters of the image forming device.
Upon a predetermined amount of lateral movement, the pawl 70 eventually contacts the leg 93 of the second gear 90. The pawl 70 is within the same plane as the leg 93 to provide for contact upon a predetermined amount of pawl movement. The second gear 90 is positioned relative to the drive gear 80 such that the toothless section 92 on the perimeter is aligned with the drive gear 80. Prior to contact between the pawl 70 and leg 93, rotation of the drive gear 80 does not translate to the second gear 90 because the toothless section 92 does not provide for the teeth 81, 91 of the two gears to intermesh and the leg 93 is positioned above the edge of the drive gear teeth 81.
When an adequate amount of toner is within the reservoir 20, the amount of angular displacement of the paddle 11 results in a minimal amount of radial movement of the pawl 70. Thus, there is no contact when the pawl extension 71 rotates past the leg 93. As images are printed, the amount of toner passed from the reservoir to the PC drum 122 reduces the toner level. Eventually, the toner level will decrease to a level causing the paddle 11 to have an angular displacement ahead of the drive gear 80 an adequate amount resulting in the pawl extension 71 contacting the leg 93.
As the pawl extension 71 contacts the leg 93, the pawl 70 transfers rotation to the second gear 90 and rotates the second gear 90 and amount for the drive gear teeth 81 to mesh with the second gear teeth 91. This results because the drive gear 80 and the second gear 90 are positioned within the same plane. The continuous rotation of the drive gear 80 result in one complete rotation of the second gear 90 until the toothless section 92 is again positioned adjacent to the drive gear teeth 81 and the process is repeated.
The developer unit 18 is positioned within the body 101 of the image forming device 100 for the second gear 90 to mesh with gear 63 on the toner cartridge 50 (see
This process of continual replenishment of toner within the reservoir 20 continues until all the toner within the cartridge 50 is extinguished. At that point, additional toner level sensors may be mounted within the cartridge 50 to indicate to a user that a new cartridge is required. One example of a toner sensor system is disclosed in U.S. Pat. No. 6,510,291 herein incorporated by reference. Terms such as “first”, “second”, and the like, are also used to describe various elements, regions, sections, etc and are also not intended to be limiting. The terms “having”, “containing”, “including”, “comprising” and the like are open ended terms that indicate the presence of stated elements or features, but do not preclude additional elements or features. The articles “a”, “an” and “the” are intended to include the plural as well as the singular, unless the context clearly indicates otherwise.
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. 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.
