Patent Grant
10534314
This application relates generally to a fan and cooling duct for an electrostatic process unit (EPU), and more particularly to a fan impeller secured to a rotating EPU shaft and an associated cooling duct for cooling EPU components.
Document processing devices include printers, copiers, scanners and e-mail gateways. More recently, devices employing two or more of these functions are found in office environments. These devices are referred to as multifunction peripherals (MFPs) or multifunction devices (MFDs). As used herein, MFP means any of the forgoing.
An electrostatic process unit (EPU) in many toner-based printers and multifunction peripherals performs the printing function. The EPU typically comprises a photoconductive drum, and a developer roller, and can include a charge unit, a toner hopper, a semiconductor laser and developer, among other components as would be known in the art. The EPU can be configured as a field replaceable unit or can be part of a self-contained compact cartridge that includes the toner. Using magnetic and electrostatic forces, the developer roller and the photoconductive drum transfer toner from a toner hopper to a sheet of paper where it is fused by heat to the paper. After the photoconductive drum transfers toner to the paper, a cleaner blade in the EPU removes residual toner and paper dust from the photoconductive drum.
EPUs are disposed inside printers and can become hot during normal operation, both due to the EPU operation itself and due to the operations of other components inside the printer chassis. Excessive heat inside an EPU can degrade the toner present in the EPU. Heat also increases stresses on EPU components which shortens the useful lifespan of EPUs and increases the frequency of maintenance that is required to maintain printers in an operational state.
Various embodiments will become better understood with regard to the following description, appended claims and accompanying drawings wherein:
The systems and methods disclosed herein are described in detail by way of examples and with reference to the figures. It will be appreciated that modifications to disclosed and described examples, arrangements, configurations, components, elements, apparatuses, devices methods, systems, etc. can suitably be made and may be desired for a specific application. In this disclosure, any identification of specific techniques, arrangements, etc. are either related to a specific example presented or are merely a general description of such a technique, arrangement, etc. Identifications of specific details or examples are not intended to be, and should not be, construed as mandatory or limiting unless specifically designated as such.
In an example embodiment, an apparatus includes a fan impeller that is coupled to a shaft of a rotating component of an electrostatic process unit. A cooling duct in fluidic communication with the fan impeller directs air from the fan impeller across a portion of the electrostatic process unit to cool components.
In toner-based electro-photographic printers, the electrostatic process unit, or EPU, selectively transfers toner from an associated toner hopper to a transfer belt for printing images and text onto paper in accordance with user print jobs. EPU components can become hot during normal print operations, especially during periods of frequent use. EPUs are disposed inside printers in an enclosed space. As a result EPUs can become overheated both from heat generated by operation of the EPU itself and from heat generated by nearby components in the printer. Excessive heat can degrade toner present in the EPU which can result in lower quality images and other problems. High temperatures also increase stress on EPU components, which can reduce the useful life of the EPU and increase future maintenance needs.
To prevent overheating, printers can reduce printing speeds in order to limit the amount of heat generated by the EPU. Printers also can incorporate additional fans and motors to circulate air and cool components, but that can increase costs and complexity and motors may need to be controlled by a suitable motor controller. Compact printers are especially prone to overheating due to the close proximity of components to one another. However, in compact printers it may be impractical to add dedicated fans and motors to cool components as these fans and motors take up additional space and increase costs.
In an example embodiment, to cool components in an EPU, a fan impeller is coupled to an existing rotating shaft of one of the EPU components. When the shaft rotates, the fan impeller also rotates which forces air into an associated cooling duct that directs the airflow across portions of the EPU to cool components.
With reference to
With reference to
As the photoconductive drum 214 rotates, toner 202 on the photoconductive drum 214 is selectively pulled from developer 208 to the photoconductive drum 212 in accordance to the image to print. The photoconductive drum 212 transfers the toner 202 to a transfer belt (not shown) and then to paper (not shown) after which the toner 202 is permanently fused to the paper by a fusing assembly (not shown). After transferring toner 202 to the transfer belt, the photoconductive drum 212 continues to rotate towards a cleaner blade 218 that removes any residual toner and other particles that remain on the photoconductive drum 212. A recovery blade 216 prevents removed toner and other particles from escaping from this section of the developer cavity 222 into other parts of the developer cavity 224. An auger 220 moves waste toner and other particles out of the EPU to a suitable waste receptacle.
Each of the rotatable components of the electrostatic process unit 200, for example the developer 208, the photoconductive drum 214, the mixers 206a and 206b and the waste auger 220, are mounted on a rotatable shaft. The shafts can be suitably coupled to one another where appropriate or driven by independent motors as would be understood in the art.
With reference to
When the associated shaft turns, the fan impeller 304 turns and draws air through an inlet 308 in a shroud 309 that partially surrounds the fan impeller 304. The shroud 309 can be separate or part of the cover of the developer or any other component of the electrostatic process unit 302. When turned, the fan impeller 304 pushes air into the cooling duct 306. The cooling duct 306 receives air from the fan impeller 304 and directs the airflow 310 to the components of the electrostatic process unit 302 to be cooled.
The cooling duct 306 can be shaped in any suitable configuration and can be closed or partially open. For example, in certain embodiments the cooling duct 306 can be a closed tube constructed of a heat conductive material such as copper. In these embodiments, the cooling duct 306 can be in direct contact with a component that is cooled by conduction through the walls of the closed tube. For example, the cooling duct 306 can be a closed tube that passes through the interior of the electrostatic process unit 302, where toner may be present, to contact the components to be cooled. A closed tube advantageously would prevent stray toner from escaping or mixing with the airflow 310. In certain other embodiments, the cooling duct 306 can be partially open and operates by directing the airflow 310 across an exterior surface of one of the components which cools the component by convection. For example, as illustrated in the partial view of
Advantageously, the fan impeller 304 and cooling duct 306 provide a simple, low-cost solution for cooling desired components of the electrostatic process unit 302 without requiring separate fans and motors. By comparison, adding separate fans and motors would not only take up valuable space inside the printer, but would also require control by a suitable motor controller, thereby increasing both cost and complexity. Advantageously, the disclosed fan impeller 304 and cooling duct 306 can allow existing electrostatic process units 302 to be retrofitted to include the fan impeller 304 and cooling duct 306. Advantageously, the disclosed fan impeller 304 and cooling duct 306 can be configured to substantially conform to the footprint of existing electrostatic process units 302 in the field, thereby allowing existing electrostatic process units 302 to be replaced with electrostatic process units 302 that include the fan impeller 304 and cooling duct 306.
With reference to
At process block 404, a print operation is initiated on the printer, for example in response to receiving a print request from a user to print a document. Processing continues to process block 406.
At process block 406, in response to initiating the print operation, certain components of the EPU rotate in a coordinated fashion as describe in detail above, including the toner mixers, the photoconductive drum, the developer roller, and the waste toner auger. Processing continues to process block 408.
At process block 408, as the shafts rotate a fan impeller suitably connected to one of the shafts also rotates. The fan impeller can be pressed onto the shaft or suitably connected via gearing or other means as would be understood in the art. As the fan impeller turns, air is drawn through an inlet by the fan impeller and directed into a cooling duct. Processing continues to process block 410.
At process block 410, the cooling duct receives the air from the fan impeller and directs the air through the cooling duct. As air passes through the cooling duct it cools nearby components of the EPU. The cooling duct can be shaped in any suitable configuration and can be closed or partially open. In certain configurations the cooling duct can direct air through the interior of the EPU, for example through a closed tube. The closed tube may be constructed of a heat conductive material such as copper. The closed tube may be in contact with one or more components in the interior of the EPU. In other configurations the cooling duct can be a partially open tube that directs air across the surface of a component, for example by directing air across the outside of a component. Processing continues to process block 412.
At process block 412, the print operation is completed, and the EPU performs any necessary operations to configure the components for the next print job. Processing then returns to process block 404 where the next print job is received and the cycle is repeated. Processing can terminate at any suitable block, for example when the printer finishes a print job, when the printer enters a sleep or idle mode, or when the printer is turned off.
In light of the foregoing, it should be appreciated that the present disclosure significantly advances the art of cooling electrostatic process units. While example embodiments of the disclosure have been disclosed in detail herein, it should be appreciated that the disclosure is not limited thereto or thereby inasmuch as variations on the disclosure herein will be readily appreciated by those of ordinary skill in the art. The scope of the application shall be appreciated from the claims that follow.
| Number | Name | Date | Kind |
|---|---|---|---|
| 7046940 | Kim | May 2006 | B2 |
| 8538286 | Brown et al. | Sep 2013 | B2 |
| 9158272 | Okabe | Oct 2015 | B2 |
| 9176464 | Kwon | Nov 2015 | B2 |
| Number | Date | Country |
|---|---|---|
| 2002278211 | Sep 2002 | JP |
