JP3055213B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus in which heat generated in the vicinity of a heat fixing device is prevented from adversely affecting other members.

[0002]

2. Description of the Related Art In an image forming apparatus using an electrophotographic method, such as an electrophotographic copying machine, a toner image formed on a photosensitive drum is transferred onto a sheet, and the sheet carrying the toner image is fixed through a fixing device and copied. Is used. As the fixing device used in the image forming apparatus, a heating roller type device is often used because its mechanism is simple, the usage record is extremely large, and maintenance is easy. . In the fixing device of the heating roller type, a heating roller having a built-in heating source and a pressure roller are arranged to face each other, and when a sheet carrying an unfixed toner image is passed between the rollers, heat is applied. And pressure to fix the toner.

As the fixing device, for example, Japanese Utility Model Laid-Open No.
An apparatus as disclosed in JP-A-81540 is known. In the fixing device shown in the above-mentioned conventional example, an air passage through which cooling air passes is disposed above the frame of the device, and means is used which can prevent overheating of a member disposed above the fixing device. Further, the air passage is provided at the upper part of the fixing device and also provided in the image forming apparatus main body. The air passage is communicated to allow air to flow, and the air passage is disposed at the upper portion by the heat of the fixing device. It is possible to prevent a heated device or the like from being heated.

[0004]

However, the heat generated from the fixing device does not affect only the upper device, but also the devices disposed on the side of the fixing device. However, there is a problem that it has a significant effect. Further, as the image forming apparatus is downsized, a device for forming an electrophotographic toner image is arranged at a position close to the fixing device. It is necessary to shut off from
However, as a cooling unit for the fixing device, a frame member provided with a heat insulating material, which is generally used conventionally, may be used, or a unit for sucking air by a paper conveying device, or a cooling unit flowing inside the device. Only a mechanism such as using air is adopted.

Further, in order to provide a heat shielding means to the side of the fixing device so that the heat of the fixing device does not affect other devices such as the photosensitive drum, for example, it is necessary to open the fixing device. Means shown in JP-A-54-94336 and the like can be used. In the conventional example, a heat shield is disposed in a paper path connecting the image transfer unit of the photosensitive drum and the fixing device, and only when performing the fixing operation, the heat shield is opened so that the fixing is performed. Ensures that the heat of the device does not affect other devices. However, in an apparatus such as a general electronic copying machine, if the paper path is provided by being divided by upper and lower guide plates, there is a problem that the configuration of the paper path becomes complicated and jam processing becomes troublesome. is there. On the other hand, it has been proposed to form an air curtain around the fixing device. However, when an air curtain is formed around the fixing device, although there is a general effect of discharging heat, radiant heat cannot be blocked, and when a cleaning device or the like is arranged at a position close to the fixing device. However, it is difficult to prevent problems such as solidification of the collected toner due to heat.

In addition to the above-described problems, for example, in a very small-sized electronic copying machine or the like, a fixing device is arranged close to an image transfer portion from a photosensitive drum, and a fixing device is provided between the two devices. It has been proposed to use a mechanism for guiding a sheet through a guide plate arranged in the paper. In the case where the above-described mechanism is used, for example, since a means for removing heat of the fixing device such as a suction conveyance device cannot be provided as in the case of a conventional image forming apparatus, the photosensitive member side is heated. The problem that the degree becomes large arises. In addition to the general electronic copying machine described above, in the case of a color electronic copying machine, a transfer drum is used to transfer a color toner image onto paper. The sheet peeling section from the transfer drum and the fixing device are arranged at positions very close to each other. Therefore, in a color electronic copying machine, the influence of the heat from the fixing device on the transfer drum and the like becomes large, and it is desired to solve the problem of the heat shielding.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the heat of a fixing device from affecting other members. It is an object of the present invention to provide a duct near a fixing device to exhaust heat around the fixing device. It was done.

[0008]

According to the present invention, there is provided an image forming apparatus in which a member for accommodating toner and other devices which are easily affected by heat are arranged in proximity to a fixing device of the image forming apparatus. Related to a cooling device. The invention according to claim 1 of the present invention is directed to a lower duct 22 that is disposed so as to cover the upper and lower stream sides and the upper side of the heating roller of the fixing device in the sheet conveying direction.
And an upper duct 21 disposed above the lower duct 22 for accommodating a member requiring cooling, and disposed on the front side of the image forming apparatus main body of the lower duct to supply external air toward the lower duct. The front suction duct 35 and the upper duct 21 are connected to the fan 24 from the rear side of the apparatus.
An air flow path for sending cold air from the portion connected to the lower duct on the front side and exhausting the air toward the lower duct, at the lower surface of the lower duct and the lower end of the side duct 30 on the upstream side of the lower duct. A suction port 31 is provided, and the air sucked from the upper duct 21 and the suction port 31 is exhausted by using an exhaust fan 25 arranged on the rear side of the lower duct. According to a second aspect of the present invention, in the first aspect, a shutter member 32 is arranged on a side of the suction port 31 at a lower end of the side duct 30 of the lower duct, and the shutter member can be opened only when a fixing operation is performed. It is characterized by doing.

[0009]

According to the above construction, in the first aspect of the present invention, the toner cartridge is provided between the toner cartridge and the fixing device and has a duct through which air flows. Even if it is arranged in the vicinity, deterioration of the toner due to heat can be prevented, and the internal space of the image forming apparatus can be effectively used while maintaining the quality of the toner. According to the second aspect of the present invention, since a duct is provided between the control substrate and the fixing device and through which air flows, even if the control substrate is disposed near the fixing device, an abnormal operation of the control substrate due to heat occurs. Can be prevented,
It is possible to effectively use the internal space of the image forming apparatus while maintaining the properties of the control board. According to the third aspect of the present invention, the flow of the air by the air blowing means is guided to the vicinity of the fixing device and the vicinity of the discharge device by the first duct and the second duct branched from the first duct. Since heat can be removed, ozone generated by the discharging means can be removed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A cooling device for an image forming apparatus according to the present invention will be described with reference to the illustrated example. The example of the present invention shown in FIG. 1 shows a cooling device 20 provided for a fixing device 15. The fixing device 15 has a heating roller 17 and a pressure roller 18 inside a frame 16 facing each other. It is arranged as such and is configured as a heating roller type device. A discharge roller 19 is provided on the copy discharge side of the fixing device, and discharges the copy toward a discharge tray or the like. With respect to the fixing device 15, a cooling device 20 provided with an air circulation path is disposed for each of the upper part and the side part. In the cooling device 20, an upper duct 21 and a lower duct 22 are provided in a double configuration above the fixing device. As will be described later, the two air passages communicate with each other on the front side of the image forming apparatus. Thus, the effect of heat shielding on the upper member can be exerted. The duct 23 is disposed on the sheet discharge side of the fixing device, and a means for preventing heat from being transmitted to the side of the image forming apparatus main body is provided.

A side duct 30 is disposed upstream of the fixing device on the sheet conveying side, and a lower suction hole 31 is provided below the side duct 30 to leak from the fixing device to the upstream side of the device. Means are provided for removing hot air by suction into the side duct 30. The side duct 30
It is also possible to arrange a structure in which a duct member for air suction is arranged at a lower portion, and a heat insulating layer is arranged at a portion of a connection portion with the duct 22 at an upper portion. Further, the shutter member 32 is slidable with respect to the side duct 30 along one vertical wall thereof.
Is provided so that the shutter member 32 can be moved up and down by a pinion 33 of a driving mechanism. The drive mechanism is operated so that the shutter member 32 is held at the raised position only during the copying operation. When the fixing device is not operated, the shutter member 32 is held at the closed position. So that the driving is controlled.

FIG. 2 shows a state in which the cooling device 20 is viewed from the front side of the image forming apparatus. The cooling device 20 includes a front suction duct 35 for the lower duct 22 and a control board disposed above the image forming apparatus. On the other hand, a state where heat is shielded is shown. Further, as shown in FIG. 2, the side duct 30 is configured to be able to suck air from an opening at a lower portion thereof. The heat shield mechanism for the toner cartridge 37 is configured as shown in FIG. As shown in FIG. 3, the upper duct 21 and the lower duct 22 disposed above the fixing device 15 are provided above a frame of the fixing device. A device such as a (PWBA) 38 is arranged so that those members are cooled by air flowing inside the upper duct 21. A front suction hole 36 is provided for the lower duct 22 so that air is sucked from the front suction duct 35 toward the lower duct 22 through the front suction hole 36 and exhausted through the lower duct 22. I do. In addition, as shown in FIG. 3, when a toner cartridge is provided corresponding to the upper part of the fixing device, the front suction duct 35 blocks transmission of heat of the fixing device to the toner cartridge. The fixing device can be heated, and the heat conducted from the fixing device by the air flowing in the front suction duct 35 can be eliminated.

The example shown in FIG. 2 shows the cooling device 20 viewed from the front side, while the example shown in FIG. 4 shows a state where the duct member is viewed from the rear side of the device. . As shown in FIG. 4, a blower fan 24 and a discharge fan 25 are arranged on the rear side of the apparatus. The blower fan 24 is arranged corresponding to the upper duct 21, and the discharge fan 25 is It is located at the exhaust port.
In addition, air is diverted from the blower fan 24 to the upper duct 21 and the branch duct 26. Air is blown from the branch duct 26 toward the charging corotron 5, and the Ozone is removed. Further, with respect to the lower duct 22, the suction force of the discharge fan 25 sucks air from the end of the upper duct 21 to circulate the air, and also sucks air from a side duct (not shown). It is configured as follows.

With the configuration described above, in the cooling device of the present invention, the cooling air is sent to the upper duct 21 by the blower fan 24 to cool the control board and the like disposed in the upper duct 21. Then, the air flowing through the upper duct 21 is supplied to the lower duct 22 as the first duct. Further, the air blown by the blower fan 24 is diverted to the branch duct 26 as a second duct provided corresponding to the upper duct 21, so that the air blows the charged corotron. . The lower duct 22 disposed below the upper duct 21 is subjected to suction by using a discharge fan 25 provided at an end on the exhaust side, so that air is directed from the upper duct 21 to the lower duct 22. And through a duct not shown,
The air suction from the side duct 30 is performed. Needless to say, air sucked from the lower suction holes 31 is used to remove heat from the upstream side of the fixing device from the side duct 30.

The cooling device of the present invention configured as described above can be applied to, for example, a color electronic copying machine 1 as shown in FIG. In the color electronic copying machine 1, a developing device 3 provided with a plurality of developing devices for a photosensitive drum 2 is disposed, a color toner image is formed on the photosensitive drum, and a color toner image is formed on a sheet supported by a transfer drum 10. I am trying to transfer it. A charging corotron 5 and a cleaning device 6 are arranged for the photosensitive drum 2 in the same manner as in the case of an image forming apparatus using a general electrophotographic method. Then, the color toner image on the photosensitive drum is transferred to the paper by the discharge from the transfer corotron 4.

In the color electronic copying machine, paper is supplied from a paper feeding device 7, and the paper is sent to a transfer drum 10 by a transport roller device 9 provided in a paper path 8. Is used to suck and hold the image by static electricity. Further, the sheet held on the transfer drum 10 is rotated once each time a color toner image is formed on the photosensitive drum 2, and each color toner image is transferred so as to overlap the sheet. Then, the sheet on which all the color toner images have been transferred is peeled off by the peeling means 11, guided to the fixing device 15 via the suction guide 12, the fixing operation is performed, and the copy is discharged to the discharge roller 19.
Through a device such as a discharge tray.

In the color electronic copying machine 1, FIG.
As shown in FIG. 4, a duct for circulating cooling air is disposed at an upper portion and a side portion of the fixing device 15, and in addition to a function of cooling a control board disposed at an upper portion of the fixing device,
The lower duct acts as a heat shield for the substrate.
Further, as shown in FIG. 3, when a toner cartridge is provided corresponding to the upper part of the fixing device, the heat of the fixing device is reduced by a front suction duct disposed between the toner cartridge and the fixing device. The transmission to the toner cartridge can be prevented. Therefore, in the cooling device of the present invention, in addition to the exhaust mechanism in the conventional electronic copying machine, since a means for exhausting heat to the fixing device is provided, other devices are arranged close to the periphery of the fixing device. In this case, the heat of the fixing device can be prevented from being transmitted to other devices.

The cooling device of the present invention configured as described above is not only applied to a color electronic copying machine as shown in FIG. 5, but is also applicable to a general electronic copying machine and the like. Applicable. And, for example, when the cleaning device is arranged close to the fixing device,
The cooling device of the present invention can be applied to a case where a control board is arranged. When each member of the image forming apparatus is compactly arranged to constitute a small-sized image forming apparatus, by using the heat shielding / cooling means of the fixing device, the influence of the heat of the fixing device is reduced. It can be prevented from reaching the device or the like.

[0019]

As described above, according to the first aspect of the present invention, since a duct is provided between the toner cartridge and the fixing device and through which air flows, the toner cartridge is fixed. Even if it is arranged in the vicinity of the apparatus, it is possible to prevent the deterioration of the toner due to heat and the like, and it is possible to effectively use the internal space of the image forming apparatus while maintaining the quality of the toner. According to the second aspect of the present invention, since a duct is provided between the control substrate and the fixing device and through which air flows, even if the control substrate is disposed near the fixing device, an abnormal operation of the control substrate due to heat occurs. Can be prevented, and the internal space of the image forming apparatus can be effectively used while maintaining the properties of the control board. According to the third aspect of the present invention, the flow of the air by the blower is guided to the vicinity of the fixing device and the vicinity of the discharge unit by the first duct and the second duct branched from the first duct. Since heat can be removed, ozone generated by the discharging means can be removed.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of a cooling device of the present invention.

FIG. 2 is a perspective view of the cooling device of the present invention as viewed from the front side.

FIG. 3 is an explanatory diagram of a heat shielding mechanism for the toner cartridge.

FIG. 4 is a perspective view of the cooling device of the present invention as viewed from the rear side.

FIG. 5 is an explanatory diagram of a color electronic copying machine to which the cooling device of the present invention is applied.

[Explanation of symbols]

1 color electronic copier, 2 photoreceptor drum, 10
Transfer drum, 15 fixing device, 16 frames,
17 heating roller, 18 pressure roller, 20 cooling device, 21 upper duct, 22 lower duct, 24
Blower fan, 25 discharge fan, 26 branch duct, 30 side duct, 31 lower suction hole, 32
Shutter member, 35 Front suction duct, 36
Front suction hole.

Continuation of the front page (56) References JP-A-62-138862 (JP, A) JP-A-3-58063 (JP, A) JP-A-2-183275 (JP, A) JP-A-57-189169 (JP) JP-A-62-206573 (JP, A) JP-A-62-135163 (JP, U) JP-A-1-120157 (JP, U) JP-A-3-35548 (JP, U) 2-35158 (JP, U) Japanese Utility Model Hei 2-81540 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 15/08-15/08 115 G03G 15/20-15 / 20 302 G03G 21/00 530-540 G03G 21/20

Claims (2)

(57) [Claims] 1. An apparatus in which a member for accommodating toner and other devices which are easily affected by heat are arranged close to a fixing device of an image forming apparatus, wherein a heating roller of the fixing device is provided. A lower duct 22 disposed so as to cover the upstream and downstream sides and the upper part of the sheet in the paper transport direction; an upper duct 21 disposed above the lower duct 22 to accommodate a member requiring cooling; A front suction duct 35 that is disposed on the front side of the image forming apparatus main body and supplies outside air to the lower duct;
And an air flow path for sending cold air from the portion connected to the lower duct on the front side and exhausting air toward the lower duct from the front side, and a lower end portion of the lower surface of the lower duct and the side duct 30 on the upstream side of the lower duct. A cooling device for an image forming apparatus, wherein a suction port 31 is provided in the cooling device, and air sucked from the upper duct 21 and the suction port 31 is exhausted by using an exhaust fan 25 disposed on the rear side of the lower duct. 2. The shutter member according to claim 1, wherein a lower end of the lower duct is provided with a shutter member at a lower end of the side duct.
2. A cooling device for an image forming apparatus, wherein the shutter member is opened only when a fixing operation is performed.