JP3905268B2 - Image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention facsimile, printer, relates to an image forming apparatus such as a copying machine, an image forming device with a damper device to mitigate the impact when closing the opening and closing door detail.
[0002]
[Prior art]
Conventionally, in an image forming apparatus such as a copying machine, when a door becomes a half-door, a user manually responds (closes), and an open / close detection sensor that is turned on / off by a protrusion provided on the inside of the door In general, the removal of a paper jam in the fixing device is generally performed by a type in which a drive system to the fixing device is shut off by opening / closing a door or a type in which a pressure is manually released by a user. Such doors are generally opened and closed using their own weights, and a torque-type damper device may be provided at the center of rotation. As a damper device for such an image forming apparatus, for example, in Japanese Patent Laid-Open No. 8-95417 and Japanese Patent Laid-Open No. 10-162684, a knob for removing a paper jam is pressed when the front door is closed. Thus, a mechanism (interlock mechanism) is described in which the interlocking device of the apparatus main body and the fixing device is released in conjunction with this pressing.
[0003]
[Problems to be solved by the invention]
In general, the doors provided in image forming devices such as copiers protect users from rotating gears and high-pressure parts in order to open and close when paper jams inside the device or when toner is replenished. It was intended to function as a protective cover only. However, in recent years, an image forming member and a transfer paper conveying member are provided inside the door to reduce the size and weight of the image forming apparatus, so that the weight of the door itself tends to increase. For this reason, if a mechanism for slowly opening and closing the door around the fulcrum is not provided, the door will open due to its own weight unless it is manually held, or members in the door opening and closing path may be damaged. , Users could get injured. Further, as a closing mechanism after the door is closed, a mechanism using a magnetized lock by a magnet, a lever and a claw is used. However, when a plurality of magnets are used, if one magnet is magnetized and the other magnets are not well magnetized, the door may be closed in a “half-door” state. On the other hand, even when the lever and the claw are used, there is a case where the image forming unit and the paper conveying unit mentioned above come in contact with each other in the process of closing the door and become a half door. When copying is performed in such a half-door state, light may enter the image forming apparatus from the outside to cause an abnormal image, or the door may open during paper transport, causing paper jams. End up.
[0004]
As a means for removing a paper jam in the fixing device, there is a method of removing the paper jam by temporarily releasing the driving of the fixing device and simultaneously releasing the pressure contact force between the fixing roller and the pressure roller. In this case, a mechanism that achieves the above-described method with a wire or cam mechanism is provided in conjunction with the opening and closing of the door. However, in a copying machine set at a low price, in addition to reducing the size and weight, the cost should be reduced. An increasing number of users perform these tasks manually. In the case of the above-described conventional publication, the size of the device itself increases as the number of parts increases, and thus it cannot cope with the recent reduction in size and weight.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides an image forming apparatus having image forming means, a fixing device, and an openable / closable door. wherein a plurality of magnets for the door to close magnetized in images forming apparatus main body, a damper device to mitigate the impact exert a biasing force in the opening direction of the door when closing the door is equipped, the damper device, When the door is provided at a position away from the magnet and the door is not completely closed, the biasing force pushes the door back in the opening direction against the magnetism of the magnet so as to avoid a half-door state. It is characterized by being comprised. According to a second aspect of the present invention, in the first aspect of the present invention, the damper device includes a damper main body and a biasing means for biasing the main body in the door opening direction, and the door is completely When the door is not closed, the damper body biased by the biasing means is configured to push the door back in the opening direction against the magnetism of the magnet to avoid a half-door state. It is what.
[0006]
The invention of claim 3 is the invention according to claim 1 or 2, door open and close detection sensor for detecting are provided to the door, when the door is fully closed, the operation of the damper device The sensor operates in conjunction with it .
[0007]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects , a magnet is provided at a tip portion of the damper device.
[0008]
The invention of claim 5 is the invention according to any one of claims 1 to 4, which operates absorbing device for gradual operation of the damper device, characterized in that it is attached to the damper device It is.
[0009]
According to a sixth aspect of the present invention, there is provided a connecting portion for connecting the damper device and the fixing device according to any one of the first to fifth aspects, the connecting portion having the door opened. In some cases, the pressure applied between the fixing roller and the pressure roller of the fixing device is released in conjunction with the operation of the damper device.
[0010]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the conventional image forming apparatus as described above, to achieve a reduction in size and weight, to avoid a half-door state, and to prevent a defect in the conveyance state and image quality. it is to provide an image forming apparatus capable.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic front view of an image forming apparatus according to the present invention. Here, the present invention is characterized in that a damper device is provided inside the door so that the door is pushed back when the door is not completely closed. With this damper device, it is possible to avoid the half-door state, and it is possible to prevent problems such as the above-described image and conveyance failure. Hereinafter, the present invention will be described in detail with reference to the drawings.
[0012]
As shown in FIG. 1, a photoconductor 2 is provided inside the image forming apparatus 1, and a charging device 3 for performing a charging process on the photoconductor 2, an original image, is provided around the photoconductor 2. An exposure device 4 having a polygon mirror for reading, a scanner unit, a CCD sensor, and the like, and irradiating the surface of the photoconductor 2 with image information by a laser beam, and a development for visualizing an electrostatic latent image exposed on the surface of the photoconductor 2 An apparatus 5, a transfer device 6 that transfers a toner image developed on the photoreceptor 2 to a sheet, and a cleaning device 7 that removes and collects toner remaining on the surface of the photoreceptor 2 after the transfer are disposed at predetermined positions. . The electrostatic latent image formed on the photoreceptor 2 is transferred to the transfer paper by the transfer device 6. A fixing device 8 for fixing an unfixed toner image on the transfer paper is disposed on the downstream side of the transfer paper transport path. The fixing device 8 includes a fixing roller 17 having a heat generating heater 9 inside and a pressure roller 18. The pressure roller 18 is moved toward the fixing roller 17 by the elasticity of a pressure spring 20 provided on the pressure lever 19. Pressurized constantly. Therefore, the unfixed toner image is fixed by the heat generated by the heater 9 and the applied pressure.
[0013]
11 is a paper feeding device for feeding paper (transfer paper). The paper in the paper feeding device 11 is raised by a spring 16 provided at the bottom of the bottom plate 11a, and the uppermost transfer paper is The paper is separated by the separating means 12 and fed by the paper feeding roller 13. The transfer paper fed in this way is abutted against the registration roller 14 and temporarily stops. Thereafter, the transfer paper is conveyed again by the rotation of the registration roller 14 in synchronism with the image on the photoconductor 2, and on the photoconductor 2. The electrostatic latent image is transferred by the transfer device 6. Next, the transfer paper is separated from the photosensitive member 2 by a separator (not shown) and then conveyed to the fixing device 8 via the conveyance path, and the copy image is fixed by the fixing device 8. Thereafter, the copy paper is discharged by the paper discharge device 15, and a series of copy operations is completed.
[0014]
A door 22 is configured to be openable and closable around a fulcrum 21. A magnet 23 is fixed to the upper end portion of the door 22, and the magnet 23 is magnetized on the main body side 1a. As a result, the door 22 is closed. As shown in FIG. 1, a damper device 24 is provided on the main body side of the image forming apparatus 1 and at a position facing the upper side of the door 22. The damper device 24 is constituted by a hollow casing cap 26, and a pressure spring 25 having a biasing force is fitted therein. Therefore, immediately before the door 22 is fully closed, the damper device 24 applies a biasing force in the direction of opening the door 22. Here, this urging force is applied even when the magnet 23 of the door 22 is magnetized on the main body 1a, that is, when the door 22 is completely closed, but the magnetizing force of the magnet 23 itself is set to be relatively strong. This prevents the door 22 from being completely closed. Even when a plurality of magnets 23 are provided to increase the magnetizing force, the holding state of the door 22 can be avoided only by the magnetizing force of only one magnet 23 by adjusting the operation stroke of the damper device 24. It becomes like this. As a result, since the door 22 is completely closed by the magnetizing force of the magnet 23, the half-door state can be avoided reliably. In addition to the pressure spring 25 of the present example, the damper device 24 may have a structure in which a casing cap 26 is covered, or a syringe type structure that utilizes the compressive force of air.
[0015]
Further, as shown in FIG. 1, when a door opening / closing detection sensor 27 is provided inside the image forming apparatus 1 in conjunction with the operation of the damper device 24, an image, a conveyance failure, etc., even in a half-door state. Can be prevented. That is, a part of the housing cap 26 of the damper device 24 is used as a pressing part 39 for turning on / off the door opening / closing detection sensor 27, and when the door 22 is closed in a completely closed state, the pressing part 39 The door opening / closing detection sensor 27 can be turned on. As a result, even when the door 22 is in a half-door state due to deformation of the door 22 or magnet magnetization failure, etc., the door open / close detection sensor 27 remains OFF in this half-door state, so the power line is cut off. The copying operation cannot be started. The door opening / closing detection sensor 27 is configured such that the door opening / closing detection sensor 27 and the pressure spring 25 are directly connected, and the door opening / closing detection sensor 27 is activated (ON) when a certain urging force is applied to the pressure spring 25. You may make it do.
[0016]
FIG. 2 shows a second embodiment of the present invention. That is, as shown in FIG. 2, a magnet 28 is provided at the tip of the damper device 24a, and an iron plate 29 is provided inside the door 22 at a position facing the magnet 28 when closed. With this configuration, the door 22 can be temporarily held by the magnetic force applied by the magnet 28 at the “b point” that is opened outward from the “a point” at which the door open / close detection sensor 27 is turned off. As a result, when the door is closed, the door and the damper device 24a are magnetized by the magnetism of the magnet. Even if the user releases the hand when the door 22 is opened, the door 22 is once opened. As a result, when the door 22 is opened again, it is possible to prevent the door 22 and nearby objects from being damaged accidentally. Here, the attachment position relationship between the magnet 28 and the iron plate 29 may be the reverse of this example, and it can be used as a substitute for the magnet 28 and the iron plate 29 as long as it has a certain strong holding force like a magic tape. is there.
[0017]
FIG. 3 shows a third embodiment of the present invention. In this embodiment, a damper device 24b is operated relatively gently by providing a torque damper device 30 at a position adjacent to the damper device 24b. That is, as shown in FIG. 3, the torque damper device 30 has a gear 31 that rotates with a certain load, and rack teeth 40 that can mesh with the gear 31 are formed below the damper device 24b. Accordingly, the gear 31 rotates in accordance with the operation of the damper device 24b, and torque (load) is generated by the torque damper device 30, so that the urging force of the pressure spring 25 is absorbed and the damper device 24b is prevented from operating suddenly. be able to. Here, there are a torque damper device 30 that generates torque only in one-sided rotation and a device that generates torque in both-sided rotation. For this reason, when there is a part that is damaged in the image forming apparatus 1 when the door 22 is suddenly closed, when the torque damper device 30 that generates torque is used for both-side rotation, the door 22 is opened even when the door 22 is closed. However, the damper device 24b can be operated with a slow operation. Thus, by slowly operating the damper device 24b, it is possible to improve the operability for the user and to produce a high-class feeling.
[0018]
FIG. 4 shows a fourth embodiment of the present invention. That is, in this fourth embodiment, the damper device 24c has a pair of housing caps 26a and 26b, and the rear end of one housing cap 26b is slidably fitted to the other housing cap 26a side. This is a sealed structure. The inner diameter dimension of the housing cap 26a and the outer dimension of the housing cap 26b are substantially the same, and a small hole 32 for exhaust is formed in the lower portion of the housing cap 26a. For this reason, during operation of the damper device 24c, as the casing cap 26b slides, compressed air acts inside the damper device 24c, so that the elasticity of the pressure spring 25 is absorbed. The operation will be relatively gentle. As a result, it is not necessary to separately provide the torque damper device 30 in the damper device 24c, which can contribute to cost reduction by reducing the number of parts.
[0019]
FIG. 5 shows a fifth embodiment of the present invention. The feature of the fifth embodiment is that the pressure of the fixing device is released by using a damper device that operates by opening a door without using a wire, a cam mechanism or the like that has been conventionally employed. That is, an extension portion 35 having a support shaft 35a is provided at the lower portion of the damper device 24d, and a support shaft 19a is also provided at the upper end portion of the pressure lever 19 that is rotatable about the support shaft 32. The connecting link 33 is rotatably interposed between the both support shafts 19a and 35a. The connecting link 33 is rotatable about the support shaft 34. For this reason, since the connecting link 33 remains biased in the X direction when the damper device 24d is not operated, the pressure roller 18 is constantly applied to the fixing roller 17 side by the elasticity of the pressure spring 20 provided on the pressure lever 19. It is pressed. On the other hand, when the door 22 is opened, the connecting link 33 is biased in the Y direction with the operation of the damper device 24d, so that the pressure lever 19 is also biased counterclockwise against the elasticity of the pressure spring 20. As a result, the pressure applied to the fixing roller 17 by the pressure roller 18 is released. As a result, it is possible to easily remove the jammed paper in the fixing device 8 or the conveyance path.
[0020]
【The invention's effect】
The present invention is as described above, and the invention according to claim 1 is an image forming apparatus having an image forming unit, a fixing device, and an openable / closable door, wherein the door is closed inside the door. a plurality of magnets to be magnetized in images forming apparatus Te, and the damper device to mitigate the impact exert a biasing force in the opening direction of the door when closing the door is equipped, the damper device is away from the magnet When the door is not completely closed, the biasing force pushes the door back in the opening direction against the magnetizing force of the magnet to avoid a half-door state. Therefore, according to a second aspect of the present invention, in the first aspect of the present invention, the damper device includes a damper main body and a biasing means for biasing the main body in the door opening direction. Is complete When the door is not closed, the damper main body biased by the biasing means is configured to push the door back in the opening direction against the magnetizing force of the magnet to avoid the half-door state. Even when the door is not completely closed, the door can be pushed back in the opening direction by the damper device, thereby avoiding a half-door state. is there.
[0021]
The invention of claim 3 is the invention according to claim 1 or 2, door open and close detection sensor for detecting are provided to the door, when the door is fully closed, the operation of the damper device Since the sensor operates in conjunction with it, even if the door is in a half-door state, the detection sensor is not turned on, so the image forming operation cannot be started. There is an effect that a defect can be prevented.
[0022]
According to a fourth aspect of the present invention, in the first to third aspects of the invention, since the magnet is provided at the tip of the damper device, even if the user releases the hand when opening the door, The door can be held in a slightly opened state, and there is an effect that it is possible to prevent a problem of accidentally damaging the door and nearby objects when the door is opened.
[0023]
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects , since the damper device is provided with an operation mitigation device that loosens the operation of the damper device. Can be performed slowly, and the operability is further improved and a high-class feeling can be obtained.
[0024]
According to a sixth aspect of the present invention, there is provided a connecting portion for connecting the damper device and the fixing device according to any one of the first to fifth aspects, the connecting portion having the door opened. Since it is configured to release the applied pressure between the fixing roller and the pressure roller of the fixing device sometimes in conjunction with the operation of the damper device, the function of the damper device is exhibited and the fixing device is opened by opening the door Since the pressure is released, there is an effect that the paper jam in the fixing device can be easily removed without bothering the user.
[Brief description of the drawings]
FIG. 1 is a schematic longitudinal sectional view showing a first embodiment of the present invention.
FIG. 2 is an enlarged view of a main part of the damper device showing the second embodiment;
FIG. 3 is an enlarged view of a main part of the damper device showing the third embodiment.
FIG. 4 is an enlarged view of a main part of the damper device showing the fourth embodiment.
FIG. 5 is an enlarged view of a main part of a damper device and a fixing device according to the fifth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Photoconductor 3 Charging apparatus 4 Exposure apparatus 5 Developing apparatus 8 Fixing apparatus
17 Fixing roller
18 Pressure roller
19 Pressure lever
20 Pressure spring
21 fulcrum
22 Door
23, 28 Magnet
24, 24a, 24b, 24c Damper device
25 Pressure spring
26, 26a, 26b Case cap
27 Door open / close detection sensor
29 Iron plate
30 Torque damper device
33 Link

Claims (6)

In an image forming apparatus having an image forming unit, a fixing device, and an openable / closable door,
The inside of the door, and a plurality of magnets to be magnetized in images forming apparatus main body by closing the door, and a damper device for alleviating the impact exert a biasing force in the opening direction of the door when closing the door comprises And
The damper device is provided at a position away from the magnet, and when the door is not completely closed, the urging force pushes the door back in the opening direction against the magnetizing force of the magnet, and the half door An image forming apparatus configured to avoid a state. Damper The damper device includes a biasing means for biasing the damper body and the body in the opening direction of the door, when said door is not fully closed, biased by said biasing means The image forming apparatus according to claim 1, wherein the main body is configured to push back the door in an opening direction against a magnetizing force of the magnet to avoid a half-door state .   The door opening / closing detection sensor for detecting opening / closing of the door is provided, and when the door is completely closed, the sensor is operated in conjunction with the operation of the damper device. Image forming apparatus.   The image forming apparatus according to claim 1, wherein a magnet is provided at a tip portion of the damper device.   5. The image forming apparatus according to claim 1, wherein an operation mitigating device for gently relaxing the operation of the damper device is attached to the damper device. 6.   A connecting portion for connecting the damper device and the fixing device is provided, and this connecting portion is connected to the fixing roller and the pressure roller of the fixing device in conjunction with the operation of the damper device when the door is opened. The image forming apparatus according to claim 1, wherein the image forming apparatus is configured to release pressure.

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