JP3609680B2 - Shutter device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shutter device for protecting an image carrier of an image forming apparatus using an electrophotographic system such as a copying machine, a printer, and a facsimile machine.
[0002]
[Prior art]
Some image forming apparatuses such as copiers, printers, and facsimiles have a shutter device for protecting the photosensitive member. Such a shutter device has a link mechanism configured to open and close the shutter member in conjunction with insertion of the image forming unit into the image forming apparatus main body and opening and closing of the cover of the image forming apparatus main body. With this link mechanism, when the image forming unit is taken out of the main body of the apparatus or when the cover that covers the transfer unit is opened, the shutter member covers the photoconductor to damage the photoconductor due to light fatigue or contact with the object. It is preventing.
[0003]
Generally, a developing unit, a registration roller, a pre-transfer conveyance guide, and the like are disposed on the upstream side of the photosensitive member, and a cleaning unit, a fixing unit, a post-transfer conveyance guide, and the like are disposed on the downstream side. It is necessary to retreat to a position that avoids these and does not hinder the conveyance of the sheet.
[0004]
[Problems to be solved by the invention]
However, as the internal structure increases in density due to downsizing of the apparatus, it becomes difficult to secure a retracting space for the shutter member. That is, the thickness of the shutter member is generally about 1.5 mm to 2 mm, and has a predetermined area for covering the image carrier.
[0005]
For example, when a retracting space cannot be secured on the upstream side of the photoconductor, the shutter member is often retracted to the vicinity of the cleaning unit (waste toner storage unit) on the downstream side of the photoconductor. The capacity decreases, or the shutter member hinders ventilation of exhaust heat from the apparatus, and the sheet transfer surface easily rubs.
[0006]
SUMMARY OF THE INVENTION An object of the present invention is to provide a shutter device that can reduce the retreat space of the shutter member.
[0007]
[Means for Solving the Problems]
The invention according to claim 1 includes a shutter member that covers a predetermined area of the image carrier, a link mechanism that moves the shutter member to a closed position that covers the image carrier and an open position that exposes the image carrier, At least a part of the shutter member is an elastically deformable film.
[0008]
In the first aspect of the present invention, for example, when the cover of the image forming apparatus is opened or the image forming unit including the image carrier is taken out from the image forming apparatus main body, the link mechanism positions the shutter member in the closed position. The shutter member covers the exposed portion (predetermined region) of the image carrier.
[0009]
On the other hand, when the cover of the image forming apparatus is closed or the image forming unit is inserted into the image forming apparatus, the link mechanism moves the shutter member from the closed position to the open position (withdraws the shutter member). When the shutter member is retracted to the open position, the film constituting the shutter member is elastically deformed by contact with a member around the retracting location and is bent toward the space of the retracting location, or Or curved along the surface.
[0010]
Therefore, the retreat space of the shutter member can be reduced. In addition, since the retracting space for the shutter member can be reduced, the retracting location of the shutter member can be selected relatively freely, and the degree of freedom in designing the link mechanism is increased. In particular, since the restriction on the space for disposing the link mechanism can be reduced, the structure of the link mechanism can be simplified and the number of parts can be reduced.
[0011]
If the film constituting the shutter member is elastically deformed toward the dead space in the image forming apparatus, the dead space can be used as a retreating place for the shutter member. As the film, a film having a thickness of about 0.1 mm to 1 mm is used.
[0012]
According to a second aspect of the present invention, in the first aspect of the present invention, the shutter member is formed in a shape along the peripheral surface of the image carrier.
[0013]
According to the second aspect of the invention, the same effect as that of the first aspect of the invention can be obtained, and the shutter can be operated when the shutter member is in the closed position or moved from the closed position to the open position. It is possible to prevent the member from coming into contact with the surface of the image carrier.
[0014]
According to a third aspect of the invention, in the first or second aspect of the invention, when the shutter member moves from the closed position to the open position, the film constituting the shutter member is a frame body that supports the image carrier. It is elastically deformed so as to overlap along the surface.
[0015]
In the invention according to claim 3, the same effect as that of the invention according to claim 1 or 2 is obtained, and the shutter member is guided by the surface of the frame and overlaps along the surface of the frame. Elastically deforms. Therefore, the retreat space of the shutter member can be further reduced.
[0016]
According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, a flexible buffer member is affixed to a surface of the shutter member on the image carrier side. .
[0017]
The invention according to claim 4 provides the same effects as the invention according to any one of claims 1 to 3, and when an external force acts on the shutter member, the shutter member faces the image carrier. Even if it is deformed, the image carrier can be prevented from being damaged. Since the buffer member has flexibility, it does not hinder elastic deformation of the film constituting the shutter member.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a cross-sectional view schematically showing an image forming case to which the present invention is applied, and FIG. 2 is a cross-sectional view showing a state in which the shutter member of FIG. 1 is retracted.
[0019]
As shown in FIG. 1, an image forming case 1 of a laser printer is formed in a cartridge shape. The image forming case 1 supplies a photoconductor 3 as an image carrier and a developer to the photoconductor 3 and develops it. A developing device 5 that performs the cleaning, a cleaning device 9 that removes the developer remaining on the photosensitive member 3, and a shutter device 11. The imaging case 1 can be detachably attached to the laser printer main body, and can be easily replaced by the user depending on the lifetime of the imaging case 1. Reference numeral 13 in the figure denotes a charging device that uniformly charges the photosensitive member 3.
[0020]
The photoreceptor 3 is uniformly charged by the charging device 13 and an electrostatic latent image is formed by a writing device (not shown). The electrostatic latent image is visualized as a developed image by supplying a developer to the developing device 5.
[0021]
Further, a part of the photosensitive member 3 is exposed from the image forming case 1, and this exposed portion T serves as a transfer portion. That is, when the developed image of the photoconductor developed by the developing device reaches the exposed portion T by the rotation of the photoconductor 3, it is transferred onto the conveyed paper in time with this developed image. . Then, after the developed image is transferred to the paper, the developer remaining on the photoreceptor 3 is removed by the cleaning device 9.
[0022]
The shutter device 11 includes a shutter member 15 that covers the exposed portion T of the photoconductor 3, a closed position that covers the photoconductor 3 (see FIG. 1), and an open position that exposes the photoconductor 3 (see FIG. 2). ) And a shutter arm (link mechanism) 17 to be moved.
[0023]
As shown in FIG. 1, the shutter member 15 covers the exposed portion T of the photoconductor 3 when the image forming unit 1 is detached from the laser printer body, and damages the surface of the photoconductor 3, light fatigue, and dust adhesion. Is to prevent. The shutter member 15 is formed in a substantially arc shape along the peripheral surface of the photoreceptor 3. Since the shutter member 15 is formed in a shape along the peripheral surface of the photoconductor 3, the surface of the photoconductor 3 when the shutter member 15 is in the closed position or when moving from the closed position to the open position. Can be prevented from contacting.
[0024]
In the present embodiment, the shutter member 15 is made of an elastically deformable thin film having a thickness of about 0.1 mm to 1 mm. As this film, a resin such as polyethylene, polycarbonate, or polyester is used. be able to. The thickness of a general shutter member is about 1.5 mm to 2 mm. Compared with this, the shutter member 15 of the present embodiment is thin, so that the retreat space can be reduced accordingly. .
[0025]
Further, a buffer member 14 having a flexibility so as not to damage the photosensitive member 3 even when contacting the photosensitive member 3 is attached to the inner surface (photosensitive member side 3) of the shutter member 15. In the present embodiment, the buffer member 14 is composed of a sponge such as felt or foamed urethane, but is not limited thereto. By attaching the buffer member 14, it is possible to prevent the photosensitive member 3 from being damaged even if the shutter member 15 is deformed toward the photosensitive member 3 when an external force is applied to the shutter member 15. Since the buffer member 14 has flexibility, the elastic deformation of the shutter member 15 is not hindered.
[0026]
The shutter arm 17 is rotatable about a rotation shaft 17a fitted to the image forming case 1, and one end of the shutter member 15 is joined. In this embodiment, the shutter arm 17 is attached to the image forming case 1 by fitting a rotating shaft 17a and a rotating shaft on the opposite side (not shown) to the image forming case 1.
[0027]
The rotating shaft 17a of the shutter arm 17 is provided with a torsion coil spring (not shown). The shutter arm 17 is moved in the direction of arrow A in FIG. 1 (the direction in which the shutter member 15 covers the photoreceptor 3) by the torsion coil spring. Always energized. Further, the image forming case 1 is provided with a projection (not shown) as a stopper of the shutter arm 17, and the shutter arm 17 biased by the torsion coil spring is locked to the projection, whereby the shutter member 15 is shown in FIG. The closed position shown in FIG.
[0028]
The shutter arm 17 is provided with a protrusion 17b that is guided by a guide (not shown) provided in the laser printer body. When the imaging case 1 is inserted into the laser printer main body, the projection 17b of the shutter arm 17 is guided by the guide of the laser printer main body, so that the shutter arm 17 resists the biasing force of the torsion coil spring. It moves in the arrow B direction. Thus, the shutter member 15 is retracted from the closed position shown in FIG. 1 to the open position shown in FIG.
[0029]
Next, the operation of the present embodiment will be described based on the configuration described above. When the imaging unit 1 is removed from the laser printer main body during maintenance such as cleaning of the laser printer, the locking state between the projection of the imaging case and the shutter arm 17 is released, and the shutter arm 17 is biased by the torsion coil spring. Thus, by moving in the direction of arrow A, the shutter member 15 moves from the open position to the closed position and covers the exposed portion T of the photoreceptor 3.
[0030]
On the other hand, when the imaging case 1 is inserted into the laser printer body, the shutter arm 17 moves in the direction of arrow B against the biasing force of the torsion coil spring by the guide of the laser printer body, so that the shutter member 15 is closed. Evacuate toward the open position. At this time, as shown in FIG. 2, the shutter member 15 is guided by the frame 3a of the photosensitive member 3 and elastically deforms so as to overlap along the surface of the frame 3a.
[0031]
Accordingly, the retreat space of the shutter member 15 can be reduced, and the retreat location of the shutter member 15 can be easily secured. On the other hand, when the shutter member 15 is not elastically deformed, the shutter member 15 moves to the position indicated by the one-dot chain line in FIG. It becomes difficult to secure.
[0032]
Further, since the retracting space of the shutter member 15 can be reduced, the retracting location of the shutter member 15 can be selected relatively freely, so that the degree of freedom in designing the shutter arm 17 is increased. In particular, since the restriction on the space where the shutter arm 17 is disposed can be reduced, the structure of the shutter arm 17 can be simplified, and the number of parts can be reduced.
[0033]
The present invention is not limited to the embodiment described above, and various modifications can be made without departing from the scope of the invention. For example, in the present embodiment, the shutter member 15 is opened / closed in conjunction with the attachment / detachment of the imaging case 1 to / from the laser printer. However, the shutter member 15 may be opened / closed in conjunction with the opening / closing of the cover of the laser printer. good. Further, the shutter device 11 may be provided in the laser printer main body.
[0035]
In the present embodiment, the entire shutter member 15 is made of a film, but a part of the shutter member 15 may be made of a film, for example, the tip of the shutter member 15 is made of a film.
[0036]
Although the present invention is applied to a laser printer, the present invention is not limited to this. For example, the same effects can be obtained when applied to an image forming apparatus such as a copying machine or a facsimile.
[0037]
【The invention's effect】
According to the first aspect of the present invention, since the film constituting the shutter member is elastically deformed, the retreat space of the shutter member can be reduced. In addition, since the retracting space of the shutter member can be reduced, the retracting location of the shutter member can be selected relatively freely. Therefore, the design freedom of the link mechanism is increased, the structure of the link mechanism can be simplified, and the number of parts can be reduced. Can be reduced.
[0038]
The invention according to claim 2 has the same effect as that of the invention according to claim 1, and when the shutter member is in the closed position or moved from the closed position to the open position, Contact with the surface of the image carrier can be prevented.
[0039]
According to the invention described in claim 3, since the same effect as that of the invention described in claim 1 or 2 is obtained, the shutter member is guided by the frame and elastically deforms so as to overlap along the surface of the frame. The retreat space for the shutter member can be further reduced.
[0040]
The invention according to claim 4 has the same effect as that of any one of claims 1 to 3, and when an external force is applied to the shutter member, the shutter member is deformed toward the image carrier. However, it is possible to prevent the image carrier from being damaged. Moreover, since the buffer member has flexibility, the elastic deformation of the film constituting the shutter member is not hindered.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing an imaging case to which the present invention is applied.
FIG. 2 is a cross-sectional view showing a state in which the shutter member of FIG. 1 is retracted.
[Explanation of symbols]
3 Photoconductor (image carrier)
3a Photosensitive member frame 11 Shutter device 14 Buffer member 15 Shutter member 17 Shutter arm (link mechanism)

Claims (6)

A shutter member that covers a predetermined region of the image carrier, a link mechanism that moves the shutter member to a closed position that covers the image carrier and an open position that exposes the image carrier, and a frame that includes the image carrier. Prepared,
At least a portion Ri elastically deformable film der, the shutter device in which the film is characterized in that is guided by the frame body to the elastic deformation of the shutter member. The shutter device according to claim 1, wherein the shutter member is formed in a shape along the peripheral surface of the image carrier. 3. The shutter according to claim 1, wherein when the shutter member moves from the closed position to the open position, the film is elastically deformed so as to overlap along a surface of a frame that supports the image carrier. apparatus. The shutter device according to claim 1, wherein a cushioning member having flexibility is attached to a surface of the shutter member on the image carrier side. An image forming apparatus comprising the shutter device according to claim 1. A shutter device according to any one of claims 1 to 4, a developing device for supplying a developer to the image carrier, and a cleaning device for removing the developer remaining on the image carrier, An image forming case that is detachable from the image forming apparatus, is formed in a cartridge shape, and moves the shutter member from the closed position to the open position by the link mechanism when the cartridge is attached to the image forming apparatus.

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