Patent Application
20110206408
1. Field of the Invention
The present invention relates to a system for cooling a developer roll inside an image forming device.
2. Description of the Related Art
An image forming device, such as a laser printer, forms a latent image on a surface of a photoconductive drum by selectively exposing an area of the surface to light. Generally, the photoconductive drum is made of photoconductive material that is discharged by light, typically emitted by a laser. As the photoconductive drum rotates, the image forming device directs a laser beam across the surface of the photoconductive drum to discharge certain points. The laser beam “draws” letters and images to be printed as a pattern of electrical charges—the latent image. The latent image is developed into a visible or a toned image by using toner.
The toner is stored in a toner cartridge housing, a small container built into a removable casing. The image forming device gathers the toner from a sump within the toner cartridge housing and supplies it to a developer roll. The developer roll is a charged rotating roller. The toner moves from the developer roll onto the latent image on the photoconductive drum to create the toned image on the photoconductive drum. The toner cartridge housing is generally sealed to prevent toner leakage. Usually, J-seals are positioned proximate both ends of the developer roll to seal the toner cartridge housing on one hand and the developer roll on the other.
However, there is friction between the developer roll and the J-seals when the developer roll rotates. The friction creates heat inside the toner cartridge. Printing at higher speeds such as at or above 50 ppm causes extreme overheating, which is localized at the ends of the developer roll around the J-seals interface. Due to overheating, the toner leaks out through the J-seals. Once toner leakage at the J-seals begins, toner loss usually continues at a rapid rate, permitting several grams of toner per minute to escape into the image forming device. Such large amounts of toner losses severely affect cartridge yield, and may result in yields of several thousand pages fewer than expected. In addition, major print defects occur as the escaped toner from the toner cartridge can spill directly onto a transfer belt near the location of a first transfer or onto print media.
One solution to prevent overheating of the developer roll is to apply a lubricant to the ends of the developer roll or to the J seals to decrease the coefficient of friction. However, the lubricant applied to the J-seals or to the ends of the developer roll may contaminate the toner and ruin any printed image. Additionally, the lubricant may seep into other areas of the toner cartridge or the image forming device, causing unwanted damage and interfere with the proper operation of the unit. Another solution to prevent overheating of the developer roll is to utilize directed airflow, such as from a fan, to blow air across the entire length of the developer roll. However, this had been found to be ineffective in lowering the temperature of the developer roll by any significant amount.
It would therefore be desirable to provide an effective cooling system that obviates the above-mentioned problems.
Disclosed herein is a system for cooling a developer roll inside an image forming device. The system includes an air duct for carrying an airflow, the air duct having at least one opening to allow airflow to pass therethrough, and at least one toner cartridge in fluid communication with the air duct, the at least one toner cartridge includes the developer roll and at least one input port disposed adjacent the developer roll, the at least one input port coupled to the at least one opening of the air duct to receive the airflow and to direct the received airflow towards the developer roll.
In some embodiments, the air duct is disposed on an inside surface of a front cover of the image forming device.
In some embodiments, the system further includes a waste toner box positioned between the air duct and the at least one toner cartridge, the waste toner box includes a channel connecting the at least one opening of the air duct to the at least one input port of the at least one toner cartridge.
In some embodiments, the waste toner box channel includes a first end coupled to the opening of the air duct and a second end coupled to the at least one input port of the at least one toner cartridge, and the coupling is provided through a sealing member.
In some embodiments, the at least one toner cartridge further includes an air conduit, the air conduit includes an elongated body having a length extending between a first end and a second end, the first end being coupled to the at least one input port for receiving the airflow and a pair of nozzles disposed along the elongated body, one of the pair of nozzles positioned to direct the received airflow at a distal end of the developer roll and the other of the pair of nozzles is positioned to direct the received airflow at a proximal end of the developer roll.
In some embodiments, the at least one opening of the air duct is coupled to the at least one input port of the toner cartridge through a seal member.
In another aspect, an image forming device includes a housing, an air duct disposed within the housing for carrying an airflow, the air duct having at least one opening to allow airflow to pass therethrough, and at least one toner cartridge in fluid communication with the air duct, the at least one toner cartridge includes a developer roll and at least one input port coupled to the at least one opening of the air duct to receive the airflow and to direct the received airflow towards the developer roll.
Additional features and advantages of the invention will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the invention as described herein, including the detailed description which follows, the claims, as well as the appended drawings.
It is to be understood that both the foregoing general description and the following detailed description of the present embodiments of the invention and are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.
The above-mentioned and other features and advantages of the various embodiments of the invention, and the manner of attaining them, will become more apparent will be better understood by reference to the accompanying drawings, wherein:
Reference will now be made in detail to the exemplary embodiment(s) of the invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used throughout the drawings to refer to the same or like parts.
Normally, the airflow is generated by an air blower 170. The air blower 170 is in fluid communication with the air duct 130. The air blower 170 may take air in from outside of image forming device 100 and force airflow into the air duct 130 through an inlet 180 of the air duct 130. The air duct 130 may be disposed on an inside surface of a front cover 310 (see
As illustrated in
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Once the opening 150 is coupled to the first end of the channel 400, the first end of the channel 400 receives the airflow from air duct 130. The received airflow moves towards the second end of the channel 400. The second end of the channel 400 channels the airflow into the input port 160 of the toner cartridge 140.
It is understood that imaging device 100 may include additional components and modules not described hereinabove but which are commonly found in imaging devices including laser printers and multifunction imaging products. For example, imaging device 100 may include a print engine which cooperates with toner cartridge 140 to impart an image on a media sheet, a media feed mechanism for picking a sheet of media from an input media stack and forwarding the picked sheet to the print engine and subsequently to a media output tray, a user interface and a controller coupled to the print engine, the media feed mechanism and the user interface for controlling same (not shown).
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.
