JP2002278363A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve air cooling efficiency by providing a rotary body in a photoreceptor drum and rotating it, and forming vortexes of an air flow in the gap (air passage) formed between the outer peripheral surface of the rotary body and the internal wall of the photoreceptor. SOLUTION: An electrophotographic image forming device equipped with a hollow cylinder type photoreceptor drum 2 having air holes 3a and 4b in drum flanges 3 and 4 which are supported rotatably on axes and provided on both axial end surfaces, a cooling fan 10 which supplies outside air into the photoreceptor drum through one air hole of the photoreceptor drum and discharge the air from the other air vent, and a duct 11 as an air flow passage connecting the cooling fan and one air vent of the photoreceptor drum has the small-diameter cylindrical rotary body 20, forming the air flow passage 21 with the internal wall of the photoreceptor drum, arranged in the photoreceptor drum to link the air flow passage and the duct to each other through one air vent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a cooling mechanism used in an image forming apparatus such as a copying machine, a laser printer, a facsimile machine, and the like, and more particularly, to efficiently cooling internal units and components to prevent the temperature thereof from rising. By
The present invention relates to an image forming apparatus that achieves stable image quality and reliability.

[0002]

2. Description of the Related Art Recent electrophotographic image forming apparatuses are required to have a higher image forming speed, and models having a copying speed of 60 sheets or more per minute are becoming mainstream. Along with this, the amount of heat generated from the heat generating unit and the heat generating component increases,
The cooling efficiency has been reduced, and measures to raise the temperature of various unit components, which have not been a problem with conventional medium-speed machines, have become more serious. In addition, as the size of the device has been reduced, it has become increasingly difficult to efficiently discharge the heat generated inside the device. In particular, since the photoconductor, which is the most important component in performing an image forming operation, is an optical semiconductor having a role of holding an electrostatic latent image that reproduces the density of an image, an increase in the temperature of the photoconductor causes an electrical problem. The resistance is reduced and the ability to retain charge is significantly impaired. Due to this, the image density of the toner image formed on the photoreceptor is reduced,
Image quality will be greatly affected. In order to solve such a problem, a method of cooling the periphery of the photoconductor by air cooling with a fan is generally used. For example, JP
In Japanese Patent Application Laid-Open No. 0-115958, a hollow metal ventilation duct is provided to thermally isolate a photosensitive unit from an adjacent fixing unit that raises the temperature of the photosensitive member. A device for cooling the periphery is disclosed. However, although this method can avoid the thermal effect from fixing, it requires a dedicated metal duct, which is not only contrary to the demand for miniaturization and high-density mounting, but also has the disadvantage of increasing the cost. Also, JP-A-2000-19
Japanese Patent No. 4230 discloses a technique in which fins are attached to both ends of a photoconductor drum so that the fins form an airflow with rotation of the drum, and the airflow is passed through the inside of the drum to cool the air. . Although this method has a simple mechanism, the number of revolutions is not as high as that of a fan, so that the generated air flow is small and it is difficult to efficiently cool the air.

[0003]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and has been made in view of the above circumstances.
An object of the present invention is to provide an image forming apparatus provided with a cooling mechanism capable of cooling a photosensitive drum in correspondence with high-density mounting of components. The problem to be solved corresponding to each claim is as follows. In the image forming process, the photosensitive drum has a function of holding an electrostatic latent image and a toner image developed from the electrostatic latent image, and transferring the toner image to paper. Since the charge holding ability is reduced, the potential of the electrostatic latent image is reduced, which causes a side effect of reducing the image density. Therefore, it is necessary to cool the photoconductor at a constant temperature by air cooling. For the air cooling, there is also a method of cooling by flowing air to the surface side of the photoreceptor. However, since the toner is fine powder, the toner scatters and contaminates surrounding units. Therefore, the disadvantage can be solved by cooling the inside of the photoreceptor, but it is difficult to efficiently cool the photoreceptor simply by creating a flow of air inside the photoreceptor. Therefore, in the present invention, a rotating body is provided inside the photosensitive drum and rotated, and a vortex of air flow is formed in a gap (vent path) formed between the outer peripheral surface of the rotating body and the inner wall of the photosensitive body. It is an object to improve air cooling efficiency. In order to form a vortex of an air flow in a ventilation path inside the photoconductor, a vortex is generated by providing a spiral groove on the surface of the rotator. And to further improve the air cooling efficiency. The helical groove provided on the surface of the rotator rotates to generate a vortex of the air flow, and the helical groove is provided in such a manner that the vortex travels toward the discharge side. It is an object of the present invention to improve the efficiency of air cooling by setting the rotation direction to be the same. The problem to be solved by claim 4 is that the vortex of the air flow has a velocity component in the length direction of the drum due to the spiral groove, and the pitch of the spiral groove becomes narrower on the discharge side, so that the velocity component increases,
The discharge speed is increased and the air cooling effect is promoted.

[0004] A jig for fixing both ends of the photosensitive drum to the apparatus main body is called a drum flange,
The vortex is generated by rotating a rotating body having a spiral groove, which is a newly provided air-cooled structure inside the drum, in synchronization with the rotation of the photosensitive drum. It is an object to promote air cooling efficiency. The object of the present invention is to improve cooling efficiency by providing ventilation holes at the drum flanges located at both ends of the photosensitive drum for guiding the air into the drum air blown from the fan and then discharging the air to the outside. I do. After the photosensitive drum is set in the apparatus main body, a face plate for fixing the drum is used, but the face plate itself is also provided with a vent to discharge air out of the apparatus, thereby improving the air cooling efficiency. That is the task. The object of the present invention is to provide a groove in the length direction of the surface of the rotating body when the rotating body is provided inside the photosensitive drum and rotated to form a vortex of the air flow in the gap inside the photosensitive body. Accordingly, it is an object to promote the generation of vortices and to further improve the air cooling efficiency. The problem to be solved by claim 9 is that, although the inside of the rotating body is hollow, the inside of the rotating body rotates to create an internal air cooling structure. Propeller-shaped blades of the axial fan are provided on the peripheral wall inside the rotating body to generate an air flow and self-cool. Claim 10
In order to provide an air flow path inside the rotating body according to the ninth aspect, ventilation holes are provided in the flanges at both ends.

[0005]

In order to solve the above-mentioned problems, according to the present invention, the drum flanges rotatably supported about an axis and provided on both end surfaces in the axial direction are provided with ventilation holes respectively. A hollow cylindrical photoreceptor drum, a cooling fan for supplying outside air to the inside of the photoreceptor drum from one ventilation hole of the photoreceptor drum and discharging the air from the other ventilation hole, and ventilation of the cooling fan and one of the photoreceptor drums A duct as an air flow path connecting between the hole and the hole, wherein a small-diameter air passage is formed between the inside of the photosensitive drum and an inner wall of the photosensitive drum. A cylindrical rotating body is arranged, and the ventilation path and the duct communicate with each other through the one ventilation hole. The invention according to claim 2 is characterized in that a spiral groove is provided on the outer peripheral surface of the rotating body. The invention according to claim 3 is directed to a traveling direction of the spiral groove,
The shape is set so that the inside air is discharged to the outside from the other ventilation hole when the rotating body rotates. The invention according to claim 4 is characterized in that the pitch of the spiral groove provided on the outer peripheral surface of the rotating body is configured to be denser from one ventilation hole for introducing outside air to the other ventilation hole for discharging. Features. The invention according to claim 5 is characterized in that the rotating body is configured to rotate integrally with the photosensitive drum in synchronization with the photosensitive drum. According to a sixth aspect of the present invention, the drum flanges provided on both end surfaces of the photosensitive drum fix both ends of the photosensitive drum and introduce air into a ventilation path between the rotating body and the inner wall of the photosensitive drum. And a vent hole for discharging. The invention of claim 7 is
A vent plate for exhaust, which communicates with a vent hole provided in the drum flange, is provided on a face plate supporting the other drum flange of the photosensitive drum. The invention according to claim 8 is characterized in that the outer peripheral surface of the rotating body is provided with a plurality of lateral grooves extending in the axial direction. The invention according to claim 9 is characterized in that a plurality of propellers for generating a flow inside the rotating body are provided on the inner peripheral surface of the rotating body.
According to a tenth aspect of the present invention, the drum flanges provided at both ends in the axial direction of the photosensitive drum are provided with ventilation holes.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. FIG. 1A is a schematic configuration diagram of an image forming apparatus including a cooling mechanism according to an embodiment of the present invention, and FIGS. 1B and 1C are an exploded perspective view of the entire cooling mechanism and a cross-sectional view of a main part. FIG. 2 is a perspective view showing the structure of the photoconductor drum, and shows an air cooling mechanism inside the photoconductor drum. The hollow cylindrical photosensitive drum 2 disposed inside the apparatus main body 1 of the image forming apparatus has a configuration in which drum flanges 3 and 4 are fixed to both end surfaces in the axial direction, and at least one of the drum flanges 3 and 4 (In this example, the front drum flange 4) is rotatably supported by a face plate 5 described later provided on the apparatus main body side. Each drum flange 3, 4 has a ventilation hole 3a, 4a, respectively. A drive shaft 15 is fixed in the center hole of the rear drum flange 3,
The photoconductor and the rotating body are driven to rotate integrally. The center hole of the other drum flange 4 is supported by a shaft 16. A suction fan 10 for introducing outside air is provided behind the photosensitive drum 2.
Are arranged, and a duct 11 is arranged between the suction fan 10 and the drum flange 3 on the rear side. A small-diameter cylindrical rotating body 20 that forms a ventilation path 21 between the photosensitive drum 2 and the inner wall of the photosensitive drum 2 is coaxially arranged inside the photosensitive drum 2, and the ventilation path 21 is formed through a rear ventilation hole 3 a. And the duct 11 were communicated. External air is sucked in by a suction fan 10 provided inside the rear side of the device main body 1, the air flow is guided to the drum flange 3 by a duct flow path, the heat inside the drum is taken out, and the air is cooled and the air is cooled from the front ventilation hole 4 a. Discharge. In the present invention, in addition to this cooling configuration, a device for further improving the air cooling efficiency is provided.

In the present invention, as shown in FIG. 2, a hollow cylindrical rotating body 20 is coaxially and rotatably arranged inside a photosensitive drum. The material of the rotating body 20 is, for example, a resin material such as lightweight plastic. When the photosensitive drum 2 having a drum diameter of 80 mm is used, the rotating body 2 provided therein is used.
0 is 50 mm in diameter. The axial length is 300 mm for the photosensitive drum 2 and 280 mm for the rotating body 20.
By rotating the rotating body 20 and the photosensitive drum 2 integrally, the air introduced from the rear ventilation hole 3 a by the fan 10 becomes a spiral airflow in the ventilation path 21, so that the wall of the photosensitive body can be efficiently produced. , And can be exhausted from the front ventilation hole 4a. Thus, by inserting the rotating body into the photosensitive drum and cooling the gap inside the drum by forced air cooling, it is possible to efficiently prevent the temperature from rising.

Next, FIG. 3 is a configuration diagram of a rotating body according to another embodiment of the present invention, which is characterized in that a spiral groove 25 is provided on the outer peripheral surface of the rotating body 20. The spiral groove 25 may be single, double,..., And extends from one axial end of the rotating body 20 to the other end. In this embodiment, a spiral groove 25 having a groove width of 10 mm and a groove depth of 7 mm is provided for the rotating body 20 having the dimensions shown in FIG.
When the spiral groove 25 is formed, the air to be passed through the ventilation path 21 is agitated and swirled, and the efficiency of cooling the photosensitive drum is greatly improved as compared with the case where the surface of the rotating body is flat. It is possible to increase. Next, the spiral groove 25
Is set so that the air inside the ventilation path can be easily discharged to the outside from the exhaust side ventilation hole 4a when the rotating body 20 rotates. In other words, by configuring the shape, pitch, and the like of the spiral groove 25 so that the airflow in the ventilation path 21 is directed to the discharge direction, the stagnation of the airflow can be prevented and cooling can be performed efficiently. In this example, since the photosensitive drum rotates clockwise, the photosensitive drum is rotated in the same direction as the rotating direction of the photosensitive drum. The rotating body 20
May be configured such that the pitch of the spiral grooves 25 provided on the outer peripheral surface becomes closer from one ventilation hole 3a for introducing outside air to the other ventilation hole 4a for discharging. In this example, since the air is blown into the ventilation path 21 from the back of the device main body and discharged to the front, the spiral pitch is increased from the back to the front. By increasing the pitch of the spiral groove 25 on the discharge side, the air with the increased temperature can be discharged quickly, and the air cooling efficiency is improved. At this time, the rotating body 20 is
You may comprise so that it may rotate integrally with the photosensitive drum 2 in synchronism. That is, FIG. 4 is an explanatory diagram of the drum drive system,
FIG. 3 is a schematic diagram for transmitting power to flanges 3 and 4 for fixing the photosensitive drum. By fixing a rotating body to the flanges 3 and 4, a conventional drive system can be used as it is. By rotating the rotating body 20 in this manner, vortices can be generated and efficient air cooling can be performed. However, air cooling can be performed without providing a new drive system, and efficiency can be improved without adding cost.

Next, as shown in FIG.
Drum flanges 3 and 4 provided on both end surfaces of the photosensitive drum are fixed to both ends of the photosensitive drum, and the drum flanges 3 and 4 are provided between the outer peripheral surface of the rotating body 20 and the inner wall of the photosensitive drum 2. Vent hole 3 for introducing and discharging air into ventilation path 21
a, 4a. That is, the photosensitive drum 2 has a configuration in which a photosensitive layer is formed by coating or vapor deposition on an aluminum cylinder. However, in the air cooling method of the present embodiment, the aluminum material on the inner wall of the photosensitive drum is cooled. Become. In the present invention, ventilation openings 3a, 4a are provided as wide as possible in the drum flanges 3, 4 shown in FIG. Ventilation holes 3a,
The width of 4a is determined by the gap between the photosensitive drum and the rotating body (the ventilation path 2).
It was almost adjusted to the width of 1). In this embodiment, ventilation holes 3a serving as flow paths are provided to efficiently take in and discharge external air into the gap 21 between the photosensitive drum 2 and the rotating body 20.
By providing 4a, the air cooling efficiency could be improved.

FIG. 6 shows another embodiment of the present invention. In a face plate 30 (5) rotatably supporting a drum flange 4 in front of a photosensitive drum 2, a ventilation hole provided in the drum flange 4 is provided. An exhaust vent 30a communicating with 4a was provided. That is, after the photosensitive drum 2 is set in the apparatus main body 1, the flanges 3 and 4 for fixing the drum are inserted, and the drum is further fixed with the face plate 30, but the drum having the ventilation hole 4a located on the front side of the image forming apparatus. The ventilation plate 30a for discharging the cooling air is provided at a position corresponding to the ventilation hole 4a of the drum flange in the face plate 30 which further fixes the flange 4 in the apparatus. Can be better.

FIGS. 7A and 7B are diagrams showing the construction of a rotating body according to another embodiment of the present invention. A plurality of lateral grooves extending in the axial direction are provided on the outer peripheral surface of the rotating body 20. 35 is provided. The groove width is, for example, 10 mm, and the groove depth is 7 mm. Even if the grooves on the surface of the rotating body were the transverse grooves 35 extending in the length direction, a sufficient air cooling effect was exhibited. FIGS. 8A and 8B are a cross-sectional view and an end view of a rotating body according to another embodiment of the present invention. The rotating body 20 causes a flow inside the rotating body 20 on its inner peripheral surface. A plurality of propellers 40 are provided. That is, two sets of four propellers 40 having a shape like an axial fan were mounted inside the rotating body. With this configuration, when air cooling inside the rotating body,
The flow of air accompanying the rotation of the rotating body can be formed inside itself,
Effective for internal cooling. FIG. 9 is an end view of a rotating body according to another embodiment. In order to perform air cooling inside the rotating body, ventilation holes 3b and 4b communicating with the inside of the rotating body are provided on the inner diameter side of the drum flange. Thus, the air cooling efficiency was improved by forming the air flow path inside the rotating body.

[0012]

As described above, according to the present invention, an image provided with a cooling mechanism capable of cooling a photosensitive drum in response to downsizing of equipment and high-density mounting of housing units and components. A forming device can be provided. That is, according to the first aspect of the present invention, the rotating body is inserted into the photosensitive drum,
By cooling the gap inside the drum by forced air cooling, it was possible to efficiently prevent the temperature from rising. According to the second aspect of the present invention, by providing a spiral groove on the surface of the rotating body, the airflow forms a vortex, and as a result, it is possible to efficiently perform air cooling. According to the third aspect of the invention, since the direction of the spiral groove is on the air discharge side, efficient air cooling can be performed because the airflow is sent out. According to the invention of claim 4, by rotating the rotating body, a vortex can be generated and efficient air cooling can be performed. However, the driving force can be obtained without providing a new drive system, and the cost can be reduced. Efficiency can be improved without using it. According to the fifth aspect of the present invention, the air cooling efficiency is improved by providing a ventilation hole serving as a flow path so as to efficiently take in and discharge external air in the gap between the photosensitive drum and the rotating body. According to the sixth aspect, similarly to the fifth aspect, the air cooling efficiency is improved by forming the flow path. According to the invention of claim 7, even if the groove on the surface of the rotating body is a lateral groove extending in the length direction, a sufficient air cooling effect was exhibited. According to the invention of claim 8, since the pitch of the spiral groove is made dense on the discharge side, the air with the increased temperature can be discharged quickly,
Air cooling efficiency improved. According to the ninth aspect of the present invention, the flow accompanying the rotation can be formed by itself for the air cooling inside the rotating body, which is effective in cooling the inside. According to the tenth aspect, similarly to the fifth aspect, the air cooling efficiency is improved by forming the flow path.

[Brief description of the drawings]

FIG. 1A is a schematic configuration diagram of an image forming apparatus provided with a cooling mechanism according to an embodiment of the present invention, and FIGS.
FIG. 3 is an overall exploded perspective view of a cooling mechanism and a cross-sectional view of a main part.

FIG. 2 is a perspective view illustrating a configuration of a photosensitive drum.

FIG. 3 is a configuration diagram of a rotating body according to another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a drum drive system.

FIG. 5 is an end view of a drum flange.

FIG. 6 is a configuration diagram of a face plate.

FIGS. 7A and 7B are configuration diagrams of a rotating body according to another embodiment.

FIGS. 8A and 8B are configuration diagrams of a rotating body according to another embodiment.

FIG. 9 is a diagram showing another example of a drum flange.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Device main body, 2 photoreceptor drums, 3, 4 drum flanges, 3a, 4a ventilation holes, 5 face plates, 10 suction fans, 11 ducts, 15 drive shafts, 16 axes, 20 rotating bodies, 21 ventilation paths, 25 spiral grooves, 30a vent, 35 lateral grooves, 40 propellers.

Claims (10)

[Claims] 1. A hollow cylindrical photosensitive drum which is rotatably supported about an axis and has ventilation holes formed in drum flanges provided at both axial end surfaces, and one ventilation hole of the photosensitive drum. A cooling fan that supplies outside air to the inside of the photosensitive drum from the other and exhausts the air from the other ventilation hole, and a duct as an air flow path connecting the cooling fan and one ventilation hole of the photosensitive drum. In the electrophotographic image forming apparatus, a small-diameter cylindrical rotating body that forms a ventilation path between the photosensitive drum and an inner wall of the photosensitive drum is disposed inside the photosensitive drum,
An image forming apparatus, wherein the ventilation path and the duct communicate with each other through the one ventilation hole. 2. The image forming apparatus according to claim 1, wherein a spiral groove is provided on an outer peripheral surface of the rotating body. 3. The image according to claim 2, wherein a traveling direction and a shape of the spiral groove are set so as to discharge internal air from the other ventilation hole to the outside when the rotating body rotates. Forming equipment. 4. A helical groove provided on an outer peripheral surface of the rotating body is arranged such that pitches of the spiral grooves are increased from one vent hole for introducing outside air to another vent hole for discharge. The image forming apparatus according to claim 2, wherein: 5. The image forming apparatus according to claim 1, wherein the rotating body is configured to rotate integrally with the photosensitive drum in synchronization with the photosensitive drum. apparatus. 6. The drum flanges provided on both end surfaces of the photoconductor drum fix both ends of the photoconductor drum, and introduce and discharge air into a ventilation path between the rotating body and the inner wall of the photoconductor drum. The image forming apparatus according to any one of claims 1, 2, 3, 4, and 5, wherein the image forming apparatus has a ventilation hole through which the air flows. 7. The exhaust plate according to claim 1, wherein a face plate for rotatably supporting the other drum flange of the photosensitive drum is provided with an exhaust port for communicating with a vent hole provided in the drum flange. The image forming apparatus according to any one of claims 2, 3, 4, 5, and 6. 8. The image according to claim 1, wherein a plurality of lateral grooves extending in the axial direction are provided on an outer peripheral surface of the rotating body. Forming equipment. 9. The image forming apparatus according to claim 1, wherein a plurality of propellers for generating a flow inside the rotating body are provided on an inner peripheral surface of the rotating body. . 10. The image forming apparatus according to claim 9, wherein each of the drum flanges provided at both ends in the axial direction of the photosensitive drum has a ventilation hole.