JP2009175455A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of preventing temperature rise in an optical writing device due to residual heat from a fixing device, caused by stopping of a cooling fan in a standby mode. <P>SOLUTION: A cover member 20 is connected to the end portion of an exhaust port 9a by a hinge 21 attached to the upper end portion of the exhaust port 9a of a duct 9. The cover member 20 is attached to be freely rotatable around the hinge 21 as a supporting point in the direction of an arrow G. When the cooling fan 8 is operated and air in the duct 9 is blown from the direction of an arrow B, the cover member 20 is jumped up by the blowing force of the cooling fan 8, to open the exhaust port 9a, so that the air blown by the cooling fan 8 can be properly exhausted. On the other hand, when blowing operation by the cooling fan 8 is stopped, the cover member 20 is rotated in the direction of G by gravity by the cover member 20, to close the exhaust port 9a. Therefore, preheat C by a fixing roller 10a is prevented from entering the duct 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine or a printer, and more particularly to an image forming apparatus provided with an optical writing device having a polygon mirror.

In recent electrophotographic image forming apparatuses such as copying machines and printers, high-density mounting of components and space saving are required in response to miniaturization. As high-density mounting and space-saving progress, the problem of heat treatment is greatly highlighted, and a large heat source fixing device that heats and presses the unfixed toner image formed on the transfer material and the electrostatic latent image on the surface of the photoreceptor A cooling method of a drive motor (hereinafter referred to as a polygon motor) that rotates a polygon mirror mounted in an optical writing device that forms a problem is a problem.
In particular, in a laser beam scanning device, which is an optical writing device, the heat resistance of an optical member such as an optical lens mounted inside the housing of the laser beam scanning device is low. Problems such as a decrease in imaging performance due to expansion occur. Another cause is an increase in the temperature of the polygon motor accompanying an increase in the rotation speed of the polygon motor due to the recent increase in the speed of image forming apparatuses.
In order to suppress such a temperature increase of the polygon motor, a cooling fan that blows air that cools the polygon motor, and a duct that houses the polygon motor and blows and blows out air from the cooling fan to the drive motor. It is proposed to suppress the temperature increase of the polygon motor by blowing cooling air into the duct with a cooling fan and blowing the cooling air onto the polygon motor. (For example, see Patent Document 1)
JP 2005-91413 A

However, in the device described in Patent Document 1, in order to attach the exhaust port of the duct to the outer periphery of the image forming apparatus, it is necessary to arrange the duct long, and the occupied area of the duct becomes larger than necessary, and the image forming apparatus There is a problem that it becomes difficult to meet demands for downsizing and space saving.
In order to solve such a problem, it is conceivable to reduce the length of the duct and arrange the exhaust port of the duct in the image forming apparatus. The following problem occurs when the is disposed in the vicinity of the fixing device.
In recent image forming apparatuses such as copiers and printers, there is a demand for noise reduction in addition to miniaturization. Especially when the operation of the image forming apparatus is stopped, the mode is changed to a standby mode and all cooling fans are stopped. Therefore, the noise reduction is supported. For this reason, when the polygon motor cooling fan stops, the remaining heat of the fixing device, which is a large heat source, flows into the image forming apparatus, and may exceed the allowable temperature range of the optical writing device in the standby mode. In particular, when the duct length is shortened and the exhaust port is arranged in the vicinity of the fixing device, the residual heat of the fixing device flows back in the duct more and more instead of the chimney, and conversely the optical writing device This causes a problem that the temperature rises.

FIG. 6 is a diagram illustrating a schematic configuration of a conventional image forming apparatus, and FIG. 7 illustrates the flow of preheating from the fixing device when the cooling fan for cooling the polygon motor is stopped in the standby mode in the conventional image forming apparatus. It is a figure to do.
As shown in FIG. 6, in a conventional image forming apparatus, a light beam from a light source 3 that emits a light beam such as a laser is scanned in an optical writing device 2 that forms an electrostatic latent image on a drum-shaped photoreceptor 1. A polygon mirror 4, an fθ lens 5, a reflection mirror 6, and the like are provided. The polygon mirror 4 is rotationally driven by a polygon motor 7. Since the polygon motor 7 generates a large amount of heat when it is rotationally driven, the light writing characteristics fluctuate due to expansion of optical members such as the polygon mirror 4, the fθ lens, and the reflection mirror 6. In order to prevent this, a cooling fan 8 that blows air for cooling the polygon motor 7 is attached, and the polygon motor 7 is cooled by blowing air from the cooling fan 8 in the direction of arrow B in the duct 9 that houses the polygon motor 7. The air is discharged from the exhaust port 9a.

However, when the operation of the optical writing device 2 is stopped, the cooling fan 8 is also stopped as a countermeasure against noise as described above. Therefore, as shown in FIG. 7, the preheating from the fixing device 10, which has been at a high temperature, enters the duct 9 through the exhaust port 9 a as indicated by an arrow C, and is a metal housing 2 a such as aluminum of the optical writing device 2. As indicated by arrow D, the temperature in the housing 2a is increased, and the optical material in the optical writing device 2 may expand.
The present invention has been made in consideration of the above circumstances, and an image forming apparatus capable of suppressing a temperature increase in the optical writing device due to residual heat from the fixing device that occurs to stop the cooling fan in the standby mode. The purpose is to provide.

In order to solve the above-mentioned problems, the invention of claim 1 is a static image sensor in which a surface corresponding to an image signal is scanned from a light source by a polygon mirror rotated by a drive motor on the surface of the charged photoconductor. In an image forming apparatus including an optical writing device for forming an electrostatic latent image, a cooling fan that blows air that cools the drive motor, and a fan that houses the drive motor and blows air from the cooling fan to the drive motor And a duct member for discharging and discharging, and a lid member for closing the exhaust port is attached to the exhaust port of the duct so as to be freely opened and closed.
According to a second aspect of the present invention, in the image forming apparatus according to the first aspect, the cover member opens the exhaust port and stops the blowing by the cooling fan when blowing air in the duct by the cooling fan. The exhaust port is sometimes attached so as to close the exhaust port.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the lid member is rotatably attached to an end portion of the exhaust port by a hinge.
According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, the lid member is rotatably attached to the upper end portion of the exhaust port by a hinge, and when the air is blown by the cooling fan, When the air outlet is rotated to open the exhaust port and the air blowing by the cooling fan is stopped, the exhaust member is rotated by its own weight to close the exhaust port.
According to a fifth aspect of the present invention, in the image forming apparatus according to the first or second aspect, the lid member is rotatably attached to an end portion of the exhaust port and connected to an end portion of the lid member. The exhaust opening / closing operation is performed by a swing solenoid.
According to a sixth aspect of the present invention, in the image forming apparatus according to the fifth aspect, the swing solenoid rotates the lid member to open the exhaust port when the cooling fan blows, Control is performed so as to close the exhaust port by rotating the lid member when the blowing is stopped.

  According to the present invention, the cooling fan that blows air that cools the drive motor, and the duct that houses the drive motor and blows and discharges the air blown by the cooling fan to the drive motor are disposed, and the duct A lid member that closes the exhaust port is attached to the exhaust port of the printer so as to be openable and closable, thereby suppressing an increase in temperature in the optical writing device due to residual heat from the fixing device that occurs to stop the cooling fan in the standby mode. It is possible to provide an image forming apparatus capable of satisfying the requirements.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a cover member attached state according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view showing a closed state of the cover member exhaust port in the standby mode state of the image forming apparatus shown in FIG. is there.
The image forming apparatus according to the present embodiment includes a charging device 11 that uniformly charges the surface of the photosensitive member 1 around the drum-shaped photosensitive member 1 rotating in the direction of arrow A, and an electrostatic formed on the photosensitive member 1. A developing device 12 that supplies toner to the latent image to form a toner image and a cleaning device 13 that removes toner remaining on the photoreceptor 1 are provided. On the photosensitive member 1, there is provided an optical writing device 2 that irradiates the photosensitive member 1 with a light beam L modulated based on desired image information to form an electrostatic latent image on the surface of the photosensitive member 1. It has been.

When an image is formed on a transfer material P such as paper or a plastic sheet by such an image forming apparatus, the surface of the rotating photoreceptor 1 is first uniformly charged by the charging device 11. The surface of the photosensitive member 1 thus charged is irradiated with a laser beam L corresponding to image information from the optical writing device 2 to form an electrostatic latent image. Subsequently, the toner is supplied from the developing device 12 to the electrostatic latent image formed on the surface of the photoreceptor 1 in this way to form a toner image. The photoreceptor 1 having the toner image formed on the surface in this manner is transferred with the bias voltage applied to the transfer material P conveyed by the registration roller 14 with the conveyance timing adjusted by the transfer roller 15. To do. The transfer material P onto which the toner image has been transferred in this manner is conveyed to the fixing device 10 by an endless conveyance belt 17 stretched between the transfer roller 15 and the drive roller 16. The fixing device 10 includes a fixing roller 10a that is heated to 150 ° C. or more and rotates in the direction of arrow E, and a pressure roller 10b that rotates in the direction of arrow F and presses the fixing roller 10a. Then, the transfer material P having an unfixed toner image is conveyed between the fixing roller 10a and the pressure roller 10b while being pressed, and the unfixed toner image is heated and pressed to transfer the toner image onto the transfer material P. It is fixed to. Thereafter, the paper is transported by the transport roller 18 and the paper discharge roller 19 and discharged from the paper discharge port 22.
On the other hand, after the toner image is transferred onto the transfer material P, the toner remaining on the surface of the photoconductor 1 is removed by the cleaning device 13. Thereafter, the charge remaining on the surface of the photoreceptor 1 is neutralized by a static eliminator (not shown), and a series of image forming steps is completed. Then, as the next image forming operation with the rotation of the photosensitive member 1, the charging process of the surface of the photosensitive member 1 of the charging device 11 is started again, and the above image forming process is repeated.

As shown in FIG. 1, the optical writing device 2 in the present embodiment scans by reflecting a laser beam emitted from the light source 3 and a light source 3 that emits laser light modulated by an image signal corresponding to image information. The polygon mirror 4 to be reflected, the fθ lens 5 that forms an image of the laser beam reflected from the polygon mirror 4 on the photoconductor 1, and the laser beam that has passed through the fθ lens 5 is reflected and applied to the surface of the photoconductor 1. And a reflection mirror 6. In order to reflect and scan the polygon mirror 4, a polygon motor 7 that is rotated at a high speed is attached to a casing 2a made of metal such as aluminum.
The polygon motor 7 generates heat as it rotates at a high speed, and as described above, the polygon mirror 4 and the fθ lens may expand and deform due to the generated heat. Therefore, in the optical writing device 2 of the present embodiment, a duct 9 that houses the polygon motor 7 and guides and blows air to be cooled by the cooling fan 8 is attached below the housing 2a. The air blown by the cooling fan 8 is transferred in the direction of the arrow B, and blown to the polygon motor 7 attached therebetween to cool the polygon motor 7. Further, the blown air is discharged from the exhaust port 9a. In this case, as shown in FIG. 1, when the exhaust port 9 a is disposed in the vicinity of the fixing roller 10 a of the fixing device 10, as described above, the image forming apparatus enters the standby mode and is cooled by the cooling fan 8. When the air blowing operation is stopped, preheating of the fixing roller 10a enters from the exhaust port 9a and heats the inside of the optical writing device 2 to cause a temperature rise in the optical writing device 2.

In the present embodiment, in order to suppress such intrusion of the preheating of the fixing roller 10a into the duct 9, a lid member 20 that closes the exhaust port 9a is rotatably attached to the end of the exhaust port 9a. Yes. As shown in FIG. 2, the lid member 20 is connected to the end portion of the exhaust port 9a by a hinge 21 attached to the upper end portion of the exhaust port 9a of the duct 9, and rotates in the direction of arrow G about the hinge 21 as a fulcrum. It is attached freely. Then, when the cooling fan 8 is activated and air is blown into the duct 9 from the direction of arrow B, as shown in FIG. The air blown by the fan 8 can be appropriately exhausted.
On the other hand, when the air blowing operation by the cooling fan 8 is stopped, as shown in FIG. 3, it rotates in the G direction by its own weight by the lid member 20, and closes the exhaust port 9a. As a result, the preheating C by the fixing roller 10a is prevented from entering the duct 9. In this way, since the preheating C is prevented from entering the duct 9 by the fixing roller 10a, the heating of the optical writing device 2 is suppressed, and the temperature rise in the optical writing device 2 can be suppressed. In this case, the lid member 20 is preferably made of a plastic material having poor thermal conductivity, and it is possible to appropriately prevent the preheating from the fixing roller 10a from entering the duct.

In the present embodiment, the lid member 20 is attached to the upper end portion of the exhaust port 9a, and automatically moves downward by the weight of the lid member 20 to close the exhaust port 9a when the cooling fan 8 stops operating. However, the lid member 20 is attached to the side end portion of the exhaust port 9a, a spring member is attached to the opposite side of the hinge 21 of the lid member 20, and the spring member is pulled to connect the exhaust port 9a with the lid member 20. You may make it obstruct | occlude.
In this embodiment, the cooling fan 8 is disposed at the right end of the duct 9 so that the cooling air is blown to the polygon motor 7 in the duct 9. It is also possible to form an air inlet at the right end of the duct 9, to suck air from the air inlet by the cooling fan 8, and to blow the air blown by the air intake onto the polygon motor 7. As described above, the air blowing by the cooling fan in the present invention refers to a state in which air flows through the cooling fan by either exhalation or inhalation.

Next, the structure of the lid member that opens and closes the exhaust port 9a of the duct 9 according to another embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram showing a schematic configuration of a lid member opening / closing mechanism according to another embodiment of the present invention, and FIG. 5 is a diagram showing a state where an exhaust port is opened by the lid member of FIG.
The opening and closing of the lid member 20 according to this embodiment is such that the lower end portion of the exhaust port 9a of the duct 9 and the lower end portion of the lid member 20 are connecting members such as hinges (not shown) in the direction of the arrow H (not shown). The swing solenoid 23 is attached to the rotation shaft of the lid member 20 and the swing solenoid 23 is operated. That is, for example, when the swing solenoid 23 is turned off, as shown in FIG. 5, the rotation shaft of the lid member 20 is rotated to open the exhaust port 9a of the duct 9, and the swing solenoid 23 is turned on. As shown in FIG. 4, the exhaust port 9a of the duct 9 is closed.

As shown in FIG. 4, the operation of the swing solenoid 23 is controlled by a control unit 25 that operates according to a signal for detecting a standby mode from a standby mode detection unit 24 provided in the image forming apparatus. ing. Therefore, when the standby mode is detected by the standby mode detection unit 24, the control unit 25 is operated, the swing solenoid 23 is operated, and the cover member 20 closes the exhaust port 9a of the duct 9. Thus, when the exhaust port 9a of the duct 9 is closed by the lid member 20, the residual heat C from the fixing roller 8a of the fixing device 8 disposed in the vicinity of the exhaust port 9a enters the duct 9 as described above. This can be suppressed. As a result, a temperature rise in the optical writing device 2 can be suppressed, and fluctuations in the optical writing operation of the optical writing device 2 can be suppressed.
In this embodiment, the swing solenoid 23 in which the opening / closing operation of the lid member 20 is attached to the rotation shaft of the lid member 20 is used. However, instead of the swing solenoid 23, a solenoid in which a normal plunger moves in parallel is used. A pinion gear may be attached to the rotation shaft of the member 20, a rack gear meshing with the pinion gear may be attached to the solenoid, and the lid gear 20 may be moved left and right by operating the solenoid to open and close the lid member 20. However, when the swing solenoid 23 is used, it is advantageous because the occupied surface of the opening / closing mechanism of the lid member 20 can be reduced.

1 is a cross-sectional view illustrating a schematic configuration of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which shows the attachment state of the cover member of one Embodiment by this invention. FIG. 2 is a cross-sectional view illustrating a closed state of an exhaust port of a lid member in a standby mode state of the image forming apparatus illustrated in FIG. 1. It is a perspective view which shows schematic structure of the opening / closing mechanism of the cover member which concerns on other embodiment by this invention. It is a perspective view which shows the state which open | released the exhaust port with the cover member of FIG. It is sectional drawing which shows schematic structure of the conventional image forming apparatus. FIG. 10 is a cross-sectional view illustrating a preheating flow from a fixing device when a cooling fan for cooling a polygon motor is stopped in a standby mode in a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoconductor, 2 Optical writing device, 2a housing, 3 Light source, 4 Polygon mirror, 5 f (theta) lens, 6 Reflecting mirror, 7 Polygon motor, 8 Cooling fan, 9 Duct, 9a Exhaust port, 10 Fixing device, 10a Fixing roller, DESCRIPTION OF SYMBOLS 11 Charging device, 12 Developing device, 13 Cleaning device, 14 Registration roller, 15 Transfer roller, 20 Lid member, 21 Hinge, 23 Swing solenoid, 24 Standby mode detection unit, 25 Control unit

Claims (6)

Image formation comprising a photoconductor and an optical writing device for forming an electrostatic latent image on a charged surface of the photoconductor by scanning light corresponding to an image signal from a light source with a polygon mirror rotated by a drive motor In the device
A cooling fan that blows air for cooling the drive motor, and a duct that houses the drive motor and blows and discharges the air blown by the cooling fan to the drive motor are disposed, and the exhaust is disposed at an exhaust port of the duct. An image forming apparatus, wherein a lid member for closing a mouth is attached so as to be freely opened and closed. The image forming apparatus according to claim 1.
The lid member is attached so as to open the exhaust port when the cooling fan blows air in the duct and close the exhaust port when the cooling fan stops blowing air. Image forming apparatus. The image forming apparatus according to claim 1 or 2,
The image forming apparatus according to claim 1, wherein the lid member is rotatably attached to an end portion of the exhaust port by a hinge. The image forming apparatus according to claim 3.
The lid member is pivotally attached to the upper end portion of the exhaust port by a hinge, and when blowing by the cooling fan, the lid member is rotated by a blowing force to open the exhaust port and stop blowing by the cooling fan. In some cases, the image forming apparatus is characterized in that the exhaust member is rotated by its own weight to close the exhaust port. The image forming apparatus according to claim 1 or 2,
The image forming apparatus, wherein the lid member is rotatably attached to an end portion of the exhaust port, and an opening / closing operation of the exhaust port is performed by a swing solenoid coupled to the end portion of the lid member. The image forming apparatus according to claim 5.
The swing solenoid rotates the lid member when the cooling fan blows to open the exhaust port, and rotates the lid member when the cooling fan stops blowing to close the exhaust port. An image forming apparatus that is controlled.

Images