JP3563946B2 - Image forming device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image forming apparatus such as an electrophotographic copying machine and a printer, and more particularly, to a photosensitive drum unit which cannot be detached from an apparatus body by preventing a fixing means of a photosensitive unit from being inadvertently operated. The present invention relates to an image forming apparatus that does not perform such processing.
[0002]
[Prior art]
One example of a conventional image forming apparatus will be described with reference to FIG. In the figure, the surface of a photosensitive drum 9 as an image carrier is uniformly charged by a primary charger 12 and is exposed by a laser from a laser unit 30 to form an electrostatic latent image on the surface. Next, the toner as a developer stored in the developing device 7 is conveyed to a photosensitive drum by a developing sleeve 8 which is a developer carrying member to perform development, and a latent image is visualized to form a developed image. The developed image is transferred to a transfer material fed by a paper feeding device (not shown) by a transfer unit 31, and the transfer material is transported to a fixing unit 32, where the developed image is heated and fixed to the transfer material. The residual toner remaining on the photosensitive drum without being transferred is removed by cleaning means 11 such as a blade.
[0003]
Next, a developing device of a conventional image forming apparatus will be described with reference to FIG.
[0004]
FIG. 4A is a schematic view around the developing device in a pressed state. In this figure, reference numeral 2 denotes a photoreceptor unit having a photosensitive drum 9 in which an electrostatic latent image is formed by arranging an electric charge on a surface by an exposure unit in an electrophotographic system, and at least one of a cleaning blade 11 and a charger 12. Are unitized. Reference numeral 1 denotes a fixing unit for fixing the photoreceptor unit 2 to the image forming apparatus main body. In the illustrated example, a screw that is closed to the back side of the paper is used. Reference numeral 2A denotes a housing of the photoreceptor unit 2, in which a photosensitive drum 9, a charger 12 and the like are housed. The housing of the photoreceptor unit 2 has a flange portion 2B extending in parallel with the rotation axis of the photoreceptor drum 9, and slides the flange portion 2B onto the photoreceptor rail 2C of the device main body to push the photoreceptor main body. The unit is mounted on the apparatus main body, and a part of the photoconductor unit such as the housing is fixed to the apparatus main body by the screw.
[0005]
Reference numeral 3 denotes a developing rail for supporting the developing device 7 in the apparatus main body, and the rail supports a photosensitive unit as a pressed unit pressed by a cam 6 as a pressing unit. The developing rail 3 extends in a direction orthogonal to the extending direction of the photoconductor rail 2C, that is, the mounting direction of the photoconductor unit. Reference numeral 4 denotes a guide groove for moving the developing rail in the directions A and B, and reference numeral 5 denotes a tension spring for pulling the developing rail in the direction of arrow C. Reference numeral 6 denotes a pressure lever for pressing the developing device against the photosensitive member, and reference numeral 7 denotes a housing of the developing device.
[0006]
FIG. 4B is a detailed cross-sectional view of the above-described pressurized state, and is partially in section. In this figure, reference numeral 8 denotes a positioning roller for pressing against the surface of the photoconductor in order to accurately perform a gap between the development sleeve indicated by a broken line and the photoconductor 9, and is arranged coaxially with the development sleeve. . Reference numeral 10 denotes a pressing cam for pushing the developing rail 3 in the pressing direction and maintaining the pressing state, which is arranged coaxially with the pressing handle 6 and rotates by the same axis as the handle. Reference numeral 11 denotes a cleaning blade for scraping off residual toner remaining on the photoreceptor after the latent image is transferred to copy paper, and reference numeral 12 denotes a charging roller for applying a charge to the photoreceptor.
[0007]
FIG. 4C is a view showing a state in which the pressure of the developing device is released in order to pull out the photoconductor unit. By rotating the pressure handle 6 to move the cam 10 and moving the developing rail 3 in the direction C by the force of the spring 5, the state shown in the figure is achieved. Thereafter, the screw 1 is loosened to release the fixing of the photoconductor unit to the main body of the image forming apparatus, and the photoconductor unit is pulled out from the main body.
[0008]
Further, the relationship between the developing sleeve and the positioning rollers will be described with reference to FIG.
[0009]
FIG. 5 is an exploded perspective view showing a configuration of the developing device, and a PL line is a break line. 8 is a positioning roller and 13 is a developing sleeve. As is clear from the figure, the positioning rollers are arranged coaxially with the sleeve, one at each end of the developing sleeve.
[0010]
[Problems to be solved by the invention]
As described above, the photoconductor unit fixing screw can be loosely pulled out without performing the pressure releasing operation of the developing device. That is, since the photoconductor unit can be pulled out without releasing the pressure of the developing device, the positioning roller may be scratched in the latent image forming area on the photoconductor surface, or the developing unit and the photoconductor unit may interfere with each other. And may be damaged.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a photosensitive drum unit having a photosensitive drum on which an electrostatic latent image is formed by arranging electric charges on a surface thereof. A developing device for developing an electrostatic latent image on the photosensitive drum , which is pressed toward the mounted photoreceptor unit; a pressing unit for pressing the developing device toward the photoreceptor unit; and fixing means for fixing the unit to the apparatus main body, an image forming apparatus having the developing device in a state releasing the pressing state to the photosensitive member unit, the drawer locus of the photosensitive member unit or the fixed unit The photosensitive unit is detachable from the apparatus main body in a direction parallel to the rotation axis of the photosensitive drum, and the developing unit is disposed in a direction orthogonal to the attaching / detaching direction of the photosensitive unit. Moving and feeling Is pressed to the body unit, said shielding means, wherein said a shutter member is retractable from the developing device housing.
[0012]
According to the above configuration, after the developing device is released from the pressed state, the shielding means is separated from the drawing locus of the fixing means, for example, so that the fixing means can be pulled out and its fixing function is released. Before, the user cannot remove the photoconductor unit from the apparatus main body without permission, and it is possible to prevent the photoconductor unit from interfering with the developing device or being damaged.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS.
[0014]
Since the same parts as those in the conventional example have already been described, description thereof will be omitted as much as possible.
[0015]
FIG. 1A shows a pressed state of the developing device 7. In this figure, the photoreceptor unit 2 is detachable from the apparatus main body in a direction parallel to the rotation axis of the photosensitive drum 9, that is, in a direction perpendicular to the paper surface, and is fixed to the apparatus main body by screws as fixing means. Reference numeral 14 denotes a shutter member as a pressing means, which is a part of a component of the developing device 7, for example, a part of the housing 7A, which is provided so as to be able to protrude and retract, and which is a shutter member. To shield or open.
[0016]
Reference numeral 15 denotes a gear for rotating the member 14, and reference numeral 16 denotes a rack member for rotating the member 14 by the movement of the developing device in the A and B directions. Reference numeral 17 denotes a portion provided on the developing device housing 7 and concealing the fixing screw 1 from the external appearance. In the present embodiment, this portion alone conceals approximately half of the screw head.
[0017]
FIG. 2 is a detailed view for explaining the movement of the above-mentioned auxiliary shutter 14, showing the back side of 17. As shown in FIG. The gear 15 described above has two stages, a portion that meshes with the rack 16 and a pulley portion on which a timing belt is engaged. Reference numeral 19 denotes a timing belt which transmits the rotation of the gear 15 to the shutter member 14 in the same direction.
[0018]
As can be seen from the figure, when the developing device is released, that is, when the developing device moves in the direction B, the shutter 14 rotates from the engagement of the rack 16 and the gear 15 and is stored on the back surface of 17 which is a part of the housing 7. .
[0019]
Only in this way can the user or serviceman touch the fixed screw 1. FIG. 1B shows this state.
[0020]
Also, when the photoconductor unit is pulled out and then set again, if the developing device is in a pressurized state, the photoconductor unit interferes with the above-described shutter and housing and cannot be set.
[0021]
Further, by using the shutter housed in the housing, the above-mentioned effect can be realized while keeping the moving distance of the developing unit to a minimum, so that there is also an effect that the miniaturization of the main body is not hindered.
[0022]
Note that in the above SL embodiment, the shutter 14 or housing part 17 of the shielding means have been adapted to position the drawer locus of screws, to be located in the drawer trajectory of the photosensitive unit itself Can be. Further, as the fixing means, the photoreceptor unit can be fixed by a fixing releasing member other than the screw, which is constituted by a lever and a cam.
[0023]
[Embodiment 2]
A second embodiment of the present invention will be described with reference to FIGS.
[0024]
Note that the same components as those in the related art have already been described in the related art, and thus will not be described here.
[0025]
FIG. 3A shows the pressed state of the developing device, and FIG. 3B shows the released state.
[0026]
A pressing handle 20 for rotating the cam 6 covers and hides the fixing screw 1 of the photoconductor unit when pressed. Further, since this position is within the trajectory of the photoconductor unit, the photoconductor unit cannot be pulled out unless the handle is turned to the state shown in FIG. 3B. Also, when the photoconductor unit is set again after the photoconductor unit is pulled out, the handle and the photoconductor unit cannot interfere with each other if the pressure is maintained.
[0027]
【The invention's effect】
As described above, according to the present invention, the fixing means of the photoconductor unit cannot release the fixing unless the pressing operation of the developing device is performed. It is possible to completely eliminate the abrasion of the positioning roller on the developing device side and the damage of the developing device and the photoconductor unit due to interference between the developing device side and the latent image forming region, thereby improving the reliability of the apparatus.
[Brief description of the drawings]
FIG. 1 is a view showing a main part of an embodiment of an image forming apparatus according to the present invention; FIG. 2 is a view showing an operation mechanism of a shutter member in FIG. 1; FIG. FIG. 4 shows an example of a conventional image forming apparatus. FIG. 5 shows a relationship between a developing sleeve and rollers in the image forming apparatus of FIG. 4. FIG. Figure showing an example of the overall configuration of the system.
DESCRIPTION OF SYMBOLS 1 ... Fixed screw 2 ... Photoconductor unit 2A, 7A ... Housing 3 ... Developing rail 4 ... Guide groove 5 ... Spring 6, 20 ... Press handle 7 ... Developing unit 8 ... Present sleeve 9 ... Photosensitive drum 10 ... Cam 11 ... Cleaning Blade 12 Charger 13 Positioning roller 14 Shutter 15 Gear 16 Rack 17 Part of housing 18 Shaft 19 Belt

Claims (3)

A photosensitive drum unit having a photosensitive drum on which an electrostatic latent image is formed by disposing a charge on the surface, and a photosensitive unit detachable from the apparatus main body,
A developing device for developing the electrostatic latent image on the photosensitive drum , which is pressed toward the mounted photoreceptor unit,
Pressing means for pressing the developing device toward the photoreceptor unit,
Fixing means for fixing the photoconductor unit to the apparatus main body ,
In the image forming apparatus having
The developing device, said in a state releasing the pressing state of the photosensitive member unit, detached from the drawer locus of the photosensitive member unit or the fixed unit, the shielding means has a,
The photoconductor unit is detachable from the apparatus main body in a direction parallel to the rotation axis of the photoconductor drum, and the developing device is moved in a direction orthogonal to the mounting and demounting direction of the photoconductor unit and pressed by the photoconductor unit,
The image forming apparatus according to claim 1, wherein the shielding unit is a shutter member that can be freely protruded and retracted from a housing of the developing device. Wherein engaging the developing device gear rack of the apparatus main body, an image forming apparatus according to claim 1, characterized in that linked the timing belt turning shaft of the shutter member and the gear. The image forming apparatus according to claim 1 , wherein the pressing unit includes a cam member that presses the developing device , and an operation handle that operates the cam member.

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