Electrophotography – Internal machine environment – Forced air circulation
Reexamination Certificate
1996-12-26
2001-03-20
Pendegrass, Joan (Department: 2852)
Electrophotography
Internal machine environment
Forced air circulation
C347S152000, C361S695000
Reexamination Certificate
active
06205302
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure of a cooling device for an image forming apparatus of an electrostatic photography type mounted in a copying machine, a facsimile or a laser printer, for example.
2. Description of Related Art
A conventional image forming apparatus of this type is provided with a paper feed unit that feeds paper for the formation of an image, a processing unit that incorporates therein a photosensitive drum and a developing device for forming a toner image on the photosensitive drum, an exposure unit for forming an electrostatic latent image on the photosensitive drum, a fixing unit for heat-fixing the toner image after transfer onto the paper, a drive motor for driving rotating parts used in the above units, transmission gears, and a power source for a controller. These units are mounted to a main frame formed by a metallic plate or a synthetic resin. Further mounted to the main frame is a train of gears for the transmission of power to each of the above units. A case cover is formed of a synthetic resin so as to surround the front, rear, right and left sides of all of the main frame, the gear train and the aforesaid units. The case cover is fixed to the main frame with bolts or the like, thereby constituting a body case of the image forming apparatus.
For diminishing the heat generated from the above power source, drive motor and heating-type fixing unit, a cooling fan has heretofore been attached to the inner surface of the body case so that the direction of the wind generated from the fan is substantially horizontal or vertical.
However, in the case where the foregoing heat generating sources are located away from one another and at different heights within the body case, it is difficult to make the wind from one cooling fan advance in plural directions. Therefore, it is required to dispose cooling fans respectively at positions close to the heat generating sources, thus resulting in an increase in the manufacturing cost. Besides, it becomes necessary to ensure spaces for mounting those cooling fans and this gives rise to the problem that the size of the apparatus becomes larger.
SUMMARY OF THE INVENTION
The present invention has been accomplished for solving the above-mentioned and other problems. It is an object of the invention to provide a cooling device capable of cooling a plurality of heat generating sources efficiently by the use of a single cooling fan.
According to the present invention, a cooling device for an image forming apparatus is provided. The image forming apparatus includes a body case within which is a processing unit having at least a photosensitive body on which an electrostatic latent image is to be formed and a developing device for the formation of a toner image on the photosensitive body. An exposure unit for forming the electrostatic latent image on the photosensitive body, a fixing unit for heat-fixing the toner image after transfer onto paper, a drive motor for driving those units, and a power source are also provided in the body case. According to the cooling device, a cooling fan receptacle portion, an air passage for the drive motor in communication with the cooling fan receptacle portion, an air passage for the power source, and an air passage for the fixing unit, are formed within the body case of the image forming apparatus. In the cooling fan receptacle portion, a cooling fan is disposed slantwise with respect to the horizontal plane so that the wind generated by the cooling fan advances toward each of the above air passages.
Thus, the cooling wind generated by the cooling fan can be introduced into the plural air passages, i.e., air passage for the drive motor, air passage for the power source and air passage for the fixing unit, which are in communication with the cooling fan receptacle portion. Heat generating sources located away from one another can be cooled efficiently by a single cooling fan, and the reduction of the manufacturing cost can be attained by minimizing the number of cooling fans. Moreover, since the cooling fan is disposed slantwise with respect to the horizontal plane within the cooling fan receptacle portion, the direction of the cooling wind generated from the cooling fan has vectors in two directions, which include the horizontal direction and vertical direction. Consequently, even if the air passage for the drive motor, air passage for the power source and air passage for the fixing unit have different heights, it becomes easier to introduce the cooling wind to those air passages. Thus, the effect of decreasing the manufacturing cost can be attained by minimizing the number of cooling fans.
Preferably, in a first aspect of the present invention, a main frame is provided within the body case, and the foregoing various units are mounted on the upper surface side of the main frame, while the cooling fan receptacle portion, an air duct as the air passage for the fixing unit, the air passage for the drive motor and the air passage for the power source are formed integrally on the lower surface side of the main frame. The air duct, which is in communication with the cooling fan receptacle portion, is positioned between the processing unit and the fixing unit and extends in a direction intersecting the paper passing direction. Thus, the air duct is positioned so as to space the processing unit and the fixing unit from each other, whereby the radiant heat from the fixing unit side can be intercepted. The upper and lower surfaces of the main frame in the body case serve as a separator between the mounting portion for the above units and the air passages for cooling. Thus, the main frame can fulfill the aforesaid two functions. Further, the cooling fan receptacle portion, the air duct and the two air passages are formed integrally. Consequently, unlike the prior art, it is not necessary to use separate components for forming the air passages. Hence, the manufacturing cost can be reduced.
Preferably, in one aspect of the present invention, the cooling fan is abutted against both the lower surface of the main frame and a bottom plate that covers the lower portion of the main frame, and is supported thereby. In this way the posture of the cooling fan is maintained. Thus, the number of parts required for fixing the cooling fan becomes smaller and the labor required for assembly is minimized, so that the manufacturing cost can be reduced.
Preferably, in one aspect of the present invention, an upper plate portion of the air duct is formed in a generally inverted V shape in cross section. The lower ends of the upper plate portion having such a shape are interconnected with a separate partition plate to constitute the air duct. Since the air duct is disposed in such a manner that its upper plate portion causes the processing unit and the fixing unit to be spaced apart from each other, the radiant heat from the fixing unit side can be intercepted by the upper plate portion. At the same time, since the inner surface side of the upper plate portion is afforded the supply of cooling air that passes through the air duct, the temperature of the upper plate portion itself does not rise, and hence the cooling effect can be improved. Further, since part of the constituents of the air duct are common to the construction of the main frame, the number of parts required becomes smaller. Moreover, since the work required for creating the air duct is only the mounting of the partition plate, the assembly work is no longer troublesome, and the manufacturing cost can be reduced thereby.
Preferably, in one aspect of the present invention, the drive motor and the power source are disposed in proximity to each other on one side of the lower surface of the main frame. The air passage for the drive motor and that for the power source are formed as a common air passage. By this, the drive motor and the power source can be cooled efficiently with cooling air supplied from a single air passage, and the shape of the air passage can be simplified.
In a second aspect of the
Brother Kogyo Kabushiki Kaisha
Oliff & Berridg,e PLC
Pendegrass Joan
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