JP3503919B2 - 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 such as a copying machine having a heat fixing device for thermally fixing a toner image on a transfer paper after transferring the toner image on the transfer paper.

[0002]

2. Description of the Related Art In recent years, copiers have become more compact, and the intervals between units in the copier have become narrower. In particular, a unit arranged in the vicinity of the heat fixing unit, for example, a space between the heat fixing device and the developing unit, a space between the heat fixing device and the cleaning unit, and the like are narrow, so that the following problems occur.

[0003]

If the distance between the heat fixing device and the developing unit is narrow, the temperature of the developer rises and the toner scatters. Further, if the gap between the heat fixing device and the cleaning unit is narrow, there is a problem that the toner collecting mechanism is locked due to the adhesion of the excess toner.

In order to solve such a problem, an attempt to provide a duct, a heat shield plate, etc. is disclosed in Japanese Patent Laid-Open Nos. 3-282570 and 6-95543.
In Japanese Patent Laid-Open No. 3-282570, a heat shield member that shields heat is provided between the cleaning device and the heat fixing device.

FIG. 5 shows a schematic structure of a conventional copying machine. Stays 108a and 108b also functioning as a reinforcing plate and a heat shield plate are provided on the upper and right portions of the fixing unit 104, and the stay 108b is The photoconductor drum 101, the cleaning unit 102, and the developing unit 1 located on the right side thereof.
It is intended to prevent heat radiation and heat conduction from the fixing unit 104 with respect to No. 03. However, normal stay 1
Since the sheets 08a and 108b are made of sheet metal, their heat capacity is small and they quickly become hot, and the heat causes the photosensitive drum 101 and the like to become hot.

In Japanese Patent Laid-Open No. 6-95543, it is attempted to suppress heat conduction from the fixing unit to other members. FIG. 6 shows the internal structure of this conventional copying machine.
A fan 107a provided at the inlet of the charging charger 106 blows fresh air to the charging charger 106 in the A1 direction, and the air is charged by the fresh air.
The air is A while removing ozone generated in 06
It moves along the direction A2 and A3 to flow inside the duct stay 110, and the fan 107b discharges the air as an exhaust flow to the outside of the machine. At that time, the fixing unit 10
On the fourth side, the duct stay 110 is provided on the photosensitive drum 101.
Since they are heated to shield the heat, they are cooled by the exhaust flow of the air.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above problems and to provide an image forming apparatus capable of preventing the temperature rise of the peripheral portion of the heat fixing device.

[0008]

According to a first aspect of the present invention, there is provided an image forming apparatus having a heat fixing device for fixing a toner image on a transfer paper after transferring the toner image on the transfer paper. The heat shield device is disposed between the heat fixing device and its peripheral portion, and has a metal reinforcing member and a resin member, and at least a part of the metal reinforcing member and at least one of the resin members. The part forms a duct for guiding cooling air, the metal reinforcing member is arranged on the heat fixing device side, and the resin member is arranged on the opposite side of the reinforcing member from the heat fixing device side. Characterize. The invention according to claim 2 is characterized in that, in the invention according to claim 1, the metal reinforcing member is made of aluminum, and the cooling air is taken in from the outside of the image forming apparatus. . According to the inventions of claims 1 and 2, a reinforcing member made of metal having high heat conductivity is arranged on the side of the heat fixing device, and heat conduction to the opposite side of the reinforcing member from the side of the heat fixing device. Since a resin member having low heat transfer property is arranged and at least a part of the metal reinforcing member and at least a part of the resin member form a duct for guiding cooling air, the heat generated by the heat fixing device is ducted. The heat generated by the heat fixing device can be cooled by exchanging heat with the air introduced to the heat fixing device. By providing the resin member, the peripheral side of the heat fixing device (the side of the reinforcing member opposite to the heat fixing device side) ). As a result, it is possible to prevent the temperature of the peripheral portion of the heat fixing device from rising.

According to a third aspect of the present invention, in the first aspect of the invention, the metal reinforcing member on the heat fixing device side of the duct has an air flow path for forming an air layer. To do. In the invention according to claim 3, since the duct is formed in the metal reinforcing member, the strength is increased,
Moreover, since the air layer in the duct and the air layer in the air flow path, that is, a plurality of air layers can be formed, the conductivity of the heat generated by the heat fixing device can be reduced, and the temperature rise in the area around the heat fixing device can be more efficiently performed. Can be prevented.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the exhaust fan is provided, and an air flow path suppressing portion for guiding the air in the duct to the exhaust fan side is provided in the duct. It is characterized in that it is formed integrally. According to the invention described in claim 4, when the air is exhausted by the exhaust fan, the stagnation of the air flow in the duct can be prevented, the pressure loss of the air can be prevented, and the partial temperature rise can be prevented.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a copying machine which is an image forming apparatus of the present invention. In FIG. 1, this copying machine is an apparatus for transferring a toner image of a document onto a transfer paper P indicated by a broken line. Light is emitted from the light source to the original surface 3 on the body 1 of the copying machine, and the reflected light from the original is exposed to the photosensitive drum 7 via the optical system 5 to form an electrostatic latent image on the photosensitive drum 7. Are formed. Inside the outer cover 1A of the machine body 1 of the copying machine, the above-mentioned optical system 5, photosensitive drum 7, fixing unit 9, cleaning unit 11, developing unit 13, charging charger 15, transfer / conveying belt 17, heat shield device 19, Exhaust fan 21, paper feed tray 33
Etc. are arranged. Further, a paper feed section 23 for manual feeding is arranged on the outer cover 1A.

Between the paper feeding section 23 and the developing unit 13,
A grip roller pair 25 and a registration roller pair 27 are arranged, and the transfer paper P is fed to the paper feed tray 33 or the manual paper feed section 2 by driving these roller pairs 25 and 27.
3 is conveyed between the developing unit 13, the photosensitive drum 7, and the transfer / conveyance belt 17.

The transfer / conveyance belt 17 includes a transfer sheet P from the photosensitive drum 7 and the transfer / conveyance belt 17 to the fixing unit 9 side.
To transport. The charging charger 15 uniformly charges the surface of the photosensitive drum 7. The developing unit 13 is the photosensitive drum 7.
The electrostatic latent image formed on the surface of the is developed. The cleaning unit 11 cleans the toner and the like remaining on the surface of the photosensitive drum 7 that has been transferred. Fixing unit 9
Fixes the toner image on the transfer paper P, and the transfer paper P after the fixing is discharged to the outside by the discharge roller pair 31. The exhaust fan 21 is a fan that exhausts the inside of the machine body 1.

Next, the heat shield device 19 shown in FIG. 1 will be described. The heat shield 19 is enlarged and shown in FIG. The heat shield 19 shown in FIG. 1 is, for example, a member fixed between the left and right side plates in the machine body 1 with screws or the like, has a horizontal portion 19a and an inclined portion 19b, and has a fixing unit (heat fixing device) 9
And a cleaning unit 11, a photosensitive drum 7, and a developing unit 1 corresponding to the peripheral portion of the fixing unit 9.
It is located between 3rd grade. As shown in FIG. 2, the heat shield 19 includes a metal reinforcing member 41 and a resin member 43.
And at least a part 41a of the metallic reinforcing member 41
At least a part 43a of the resin member 43 forms a duct 45 that guides cooling air.

The metallic reinforcing member 41 is disposed on the fixing unit 9 side, and the resin member 43 is the cleaning unit 11.
And the photoconductor drum 7 and the like. The metal reinforcing member 41 is preferably made of aluminum, which has a higher thermal conductivity than resin, and the cooling air is supplied from the outside of the outer cover 1A shown in FIG.
2 is taken in from the air intake port and is passed through the duct 45 along the X direction in FIG. 2 (the direction perpendicular to the paper surface of FIG. 2).

Next, the operation of the copying machine will be described. Figure 1
The transfer paper P is driven from the paper feed tray 33 or the manual paper feed section 23 by driving the roller pair 25, 27 shown in FIG.
When the transfer paper P is conveyed between the transfer and conveyance belts 17,
The toner image on the photoconductor drum 7 is transferred by being conveyed in the T direction. When the transfer process is completed, the toner image on the transfer paper P is fixed by heat in the fixing unit 9 and is discharged to the outside of the machine body 1 by the discharge roller 31.

Toner and the like remaining on the surface of the photoconductor drum 7 after the transfer is cleaned by the cleaning unit 11, and the surface of the photoconductor drum 7 is charged again by the charging unit 13 to prepare the next latent image. Prepare

When the copying machine is operated as described above, the fixing unit 9 generates heat, but the heat shield device 19 applies the heat of the fixing unit 9 to the cleaning unit 11, which is the anti-fixing unit, the photosensitive drum 7, and the developing unit. Prevent temperature rise without transmitting to each unit such as 13. That is, the metal stay member 41, which is a duct stay, is warmed by the hot air in the upper portion of the fixing unit 9 shown in FIGS. 1 and 2, but the stand member member 41 prevents the outside air taken into the airframe 1 from the duct 45. In the X direction shown in FIG. 2 (perpendicular to the paper surface of FIG. 2)
To be cooled. Moreover, since the resin member 43 having a smaller heat conduction than that of the reinforcing member 41 is provided, the cleaning unit 1 located outside the resin member 43.
1, the temperature rise of each unit such as the photosensitive drum 7 and the developing unit 13 is prevented. As a result, the fixing unit 9, the cleaning unit 11 other than the fixing unit 9, the photosensitive drum 7 and the developing unit 1 are provided in a small space.
It is possible to secure a temperature gradient between the units such as 3 and the like and reinforce the strength of the machine body 1.

FIG. 3 shows another embodiment of the heat shield device. When the components of the heat shield device 69 are substantially the same as those of the heat shield device 19 shown in FIG. The same reference numerals are given and the description thereof is omitted. The heat shield 69 has a plurality of airflow paths 79 arranged in the duct 45 by adding a reinforcing member 77 to the heat shield 19 shown in FIG. These airflow paths 79 are integrally formed with the metallic reinforcing member 41 on the fixing unit 9 side to form an air layer. By doing this,
Although the air space passing through the duct 45 and the air flow path 79 is formed into two layers in a small occupied space, the fixing unit 9 and other units such as the cleaning unit 11, the photosensitive drum 7, and the developing unit 13 are further separated. In the meantime, it is possible to further secure the temperature gradient and reinforce the strength of the machine body 1.

FIG. 4 shows still another embodiment of the heat shield device. In the heat shield device 99 shown in FIG. 4, substantially the same parts as those of the heat shield device 19 shown in FIG. Horizontal portion 19a of the heat shield 99
An exhaust fan 97 is provided at the end portion of the, and an airflow guide 81 is integrally formed with the resin member 43 as an airflow path restraining portion in the inclined portion 19b.

As a result, when the exhaust fan 97 is rotated to take in the outside air for cooling from the outside of the machine body 1 to the inlet 94, the air passes through the inside of the duct 45 along the X direction, and in the metal reinforcing member 41. The hot air in the upper part of the fixing unit 9 is heat-exchanged and cooled. At that time, the air passing through the inside of the inclined portion 19b is guided by the airflow guide 81 and is discharged to the exhaust fan 97.
Be guided to the side. As a result, the exhaust fan 97 discharges the air that has undergone heat exchange by the metal reinforcing member 41 to the outside of the machine body 1.

[0022]

According to the first and second aspects of the present invention, the heat generated by the heat fixing device can be cooled by exchanging heat with the air introduced into the duct, and the heat generated by the heat fixing device is provided in the resin member. This prevents the transfer to the peripheral side of the heat fixing device. As a result, it is possible to prevent the temperature of the peripheral portion of the heat fixing device from rising.

According to the third aspect of the invention, since the duct is formed in the metal reinforcing member, the strength is increased, and moreover, the air layer in the duct and the air layer in the air flow path, that is, a plurality of air layers are formed. Therefore, the conductivity of the heat generated by the heat fixing device can be reduced, and the temperature rise of the peripheral portion of the heat fixing device can be prevented more efficiently.

According to the fourth aspect of the invention, when the air is exhausted by the exhaust fan, the stagnation of the air flow in the duct can be prevented, the pressure loss of the air can be prevented, and the partial temperature rise can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing an image forming apparatus of the present invention.

2 is a diagram showing an embodiment of a heat shield device used in the image forming apparatus of FIG. 1 and its surroundings.

FIG. 3 is a diagram showing another embodiment of the heat shield device used in the image forming apparatus of FIG. 1 and its surroundings.

4 is a diagram showing still another embodiment of a heat shield device used in the image forming apparatus of FIG.

FIG. 5 is a diagram showing a conventional image forming apparatus.

FIG. 6 is a perspective view showing a structure of a conventional image forming apparatus.

[Explanation of symbols]

P transfer paper 7 Photoconductor unit (parts around) 9 Fixing unit (heat fixing device) 19 Heat shield 11 Cleaning unit (peripheral area) 15 Development unit (peripheral area) 41 Metal reinforcement members 43 Resin member 45 duct 79 Airflow path 81 guide (airflow path restraint part) 97 Exhaust fan

Continuation of the front page (56) Reference JP 62-38489 (JP, A) JP 8-22157 (JP, A) JP 1-128073 (JP, A) JP 7-134533 (JP , A) JP 8-254938 (JP, A) JP 8-328410 (JP, A) JP 62-244065 (JP, A) JP 3-282570 (JP, A) JP 8-194429 (JP, A) Actual opening 63-185148 (JP, U) Actual opening 2-35158 (JP, U) Actual opening 2-81540 (JP, U) Actual opening 6-40956 (JP, U) Actual development 59-138862 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 21/20 G03G 21/00 370-540 G03G 15/20 101

Claims (4)

(57) [Claims] 1. An image forming apparatus having a heat fixing device for fixing the toner image on the transfer paper after transferring the toner image on the transfer paper, wherein a heat shield device is arranged between the heat fixing device and a peripheral portion thereof. This heat shield device has a metal reinforcing member and a resin member, and at least a part of the metal reinforcing member and at least a part of the resin member form a duct for guiding cooling air. The image forming apparatus is characterized in that the metal reinforcing member is arranged on the heat fixing device side and the resin member is arranged on the opposite side of the reinforcing member from the heat fixing device side. 2. The image forming apparatus according to claim 1, wherein the metal reinforcing member is made of aluminum, and the cooling air is taken in from outside the image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the metal reinforcing member on the heat fixing device side of the duct has an air flow path for forming an air layer. 4. An exhaust fan is provided, and an air flow path suppressing portion for guiding the air in the duct to the exhaust fan side is integrally formed with the resin member in the duct. Image forming device.