JPH055565Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an electrophotographic apparatus, and particularly to an electrophotographic apparatus having a grid protection device for a scorotron charger.

(Prior Art) In a printer device using electrophotography, a scorotron charger is used because it is necessary to more strictly control the surface potential of a photoreceptor. This scorotron charger consists of a charger main body having a shield case and a corona wire, and a grid that is attached to an opening facing the photoreceptor and electrically insulated from surrounding members. The photoreceptor is placed close to the photoreceptor and is configured to apply a predetermined bias voltage to charge the photoreceptor to a predetermined potential. When charging a photoreceptor using a scorotron charger, the distance from the grid to the surface of the photoreceptor must be extremely strictly regulated, and must be set to about 1.5 mm, for example.

On the other hand, in order to improve the maintenance of printer devices, each process element is designed into a unit, and the printer is designed as a photoreceptor unit including the photoreceptor and its surrounding members. In this case, if the photoreceptor and scorotron charger are configured separately,
When the photoreceptor unit is attached and detached, the distance from the surface of the photoreceptor to the grid changes each time the photoreceptor unit is attached and detached, resulting in an inconvenience that the charged potential of the photoreceptor changes. On the other hand, a high voltage terminal or the like must be connected to the charger body, and it is necessary to attach the charger body to the printer apparatus body from the viewpoint of electrical wiring.
For this reason, unit-designed printers require
The charger body and the grid of the scorotron charger are made into separate structures, and the charger body is attached to the printer device body side, and the grid is attached to the photoconductor unit side. We will solve the problems together.

(Problem to be solved by the invention) In a printer device that uses a scorotron charger as a separate structure between the charger body and the electrophotographic device, when the photoreceptor unit is taken out from the device body, the grid is removed from the unit. It will be exposed to the surface and may be touched by the operator's hand or collide with surrounding members. On the other hand, since the grid is composed of a mesh-like stainless steel plate with a thickness of about 0.1 mm, it is easily deformed or scratched even by the slightest external force. Even if you touch it, it will deform and become a defective part. Furthermore, the edges of the grid were sharp and could cause lacerations if touched by service personnel. Furthermore, since the eraser device is provided before the charger, the eraser light may penetrate into the charger side. There was also an inconvenience that adversely affected charging.

SUMMARY OF THE INVENTION Therefore, the purpose of the present invention is to eliminate the above-mentioned drawbacks, and to prevent the grid from being directly exposed to the outer surface of the unit when the photoreceptor unit is taken out from the apparatus main body, and to allow the photoreceptor unit to be mounted inside the apparatus main body. An object of the present invention is to provide an electrophotographic apparatus that does not sometimes interfere with the charging of a photoreceptor, prevents erasing light from going around, and can accurately charge the surface of a photoreceptor to a predetermined potential.

(Means for Solving the Problems) An electrophotographic apparatus according to the present invention includes a scorotron charger having a charger body including a shield case and a corona wire, and a grid to which a predetermined bias voltage is applied. A grid is fixed to a photoreceptor unit including a photoreceptor, the charger main body is fixed to the electrophotographic apparatus main body so as to be adjacent to the eraser device, and the photoreceptor unit is freely attachable to and detachable from the electrophotographic apparatus main body along the vertical direction. In an electrophotographic apparatus installed in The protection plate is housed in the housing of the eraser device when attached to the main body, and the protection plate faces the grid when the photoreceptor unit is taken out.

(Function) The scorotron charger is constructed as a separate structure, the grid is fixed to the photoreceptor unit, the charger body is fixed to the device body, and a protection plate is rotatably attached to the photoreceptor unit so as to face the grid. For example, when the photoconductor unit is taken out, the protection plate functions as a shutter against the grid to protect it, while when the photoconductor unit is attached to the device body, the protection plate acts as a locking member on the device body side. The corona wire is engaged with the corona wire and positioned in a direction substantially perpendicular to the grid, thereby effectively guiding the corona ions emitted from the corona wire to the photoreceptor and preventing the eraser light from going around.

(Embodiment) FIG. 1 is a diagram showing the configuration of an embodiment of an electrophotographic apparatus according to the present invention. In this example, a printer device using an electrophotographic method will be described as an example. Photoreceptor belt 1 with a predetermined recording width (perpendicular to the paper surface)
, two driving rollers 2 spaced apart from each other in a substantially vertical body.
a and 2b and run in the direction of arrow a.
The photoreceptor belt 1 may be, for example, a polyester film on which an Al conductive layer and a photoreceptor layer made of polyvinylcarbazole or the like are formed. The photoreceptor belt 1 is uniformly photostatically eliminated by an eraser device 3, and then uniformly charged to a predetermined potential by a scorotron charger 4. The strotron charger 4 has a charger main body 5 having a shield case and a corona wire, and a mesh-shaped grid 6 disposed opposite to the photoreceptor belt 1. The corona wire of the charger main body 5 is connected to a -6KV high voltage power source 7. At the same time, the grid 6 is connected to a bias power supply 8.
The grid 6 is composed of, for example, a mesh plate made of stainless steel having a large number of openings, and is arranged at a distance of 1 mm from the traveling photoreceptor belt 1 and supported by an electrically insulating member. . A desired bias voltage, for example, a DC voltage of -500 V, is applied to the grid 6 from a bias power supply 8 to charge the photoreceptor belt 1 to a surface potential approximately equal to the grid voltage. Since the charging potential of the photoreceptor belt varies greatly depending on the distance to the opposing grid 6, the distance from the grid 6 to the photoreceptor belt 1 must be regulated with high precision. The charger body 5 is attached to the printer body side, and the grid 6 is attached to the photoreceptor unit side.
The photoreceptor belt 1 charged to a predetermined surface potential is exposed by an exposure device 9 to form an electrostatic latent image. This exposure device has a light emitting diode element array in which a large number of light emitting diode elements are linearly arranged along the recording width direction, and a rod-shaped lens that focuses the light emitted from each light emitting diode element onto a photoreceptor belt 1. It consists of an array. and,
Each light emitting diode element emits light in accordance with an image signal to form an electrostatic latent image. The electrostatic latent image on the photoreceptor belt 1 is developed into a toner image by a developing device 10, and is transported to a transfer position. At the transfer position, the toner image is transferred to the recording paper 1 which is conveyed by the transfer charger 11 in synchronization with the photoreceptor belt 1.
Transferred to 2. After the transfer, the recording paper 12 is conveyed in the direction of arrow b, passes through a fixing device (not shown), and is ejected out of the machine in a face-down state. After the transfer process, the photoreceptor belt 1 has untransferred toner removed by the cleaning device 13, and is photostatically eliminated by the eraser device 3 again, and the next image forming operation is performed.

In the present invention, a unit structure is adopted to facilitate maintenance, and the photoreceptor belt 1, drive rollers 2a and 2b, transfer charger 11, cleaning device 13, and scorotron charger grid 6 are integrated as a photoreceptor unit. Configure in a specific manner. On the other hand, the eraser device 3, the charger main body 5, the exposure device 9, and the developing device 10 are constructed separately from the photoreceptor unit, and are each individually mounted on the printer main body side. Further, the photoreceptor unit is configured to be attached to the main body of the printer apparatus by being pulled up or inserted in the vertical direction.

Figure 2 shows the detailed structure of the charging device, Figure 2a is a diagrammatic sectional view showing the state of the photoreceptor unit when it is taken out, and Figure 2b is a diagrammatic cross-sectional view showing the state of the photoreceptor unit when it is taken out. FIG. 2c is a diagrammatic cross-sectional view showing a state in which the photoreceptor unit is installed in the printer main body, and FIG. The grid 6 of the strotron charger 4 is attached to an electrically insulating support member 20.
0 is fixed to the side plate (extending parallel to the plane of the paper) of the photoreceptor unit. Further, a pivot pin 21 is installed on the side opposite to the photoreceptor belt 1 across the grid 6 of the side plate, and a protection plate 22 is attached to the pivot pin 21 so as to be rotatable in the directions of arrows c and d. This protective plate 22 is made of a metal plate or a plastic plate and has a size that substantially covers the entire surface of the grid 6. Therefore, when the photoreceptor unit is taken out from the printer main body upwards, the protective plate 22 extends parallel to the grid 6 due to the action of gravity, covers the back side of the grid 6, and protects the photoreceptor unit. Horizontally, grid 6 is photoreceptor belt 1
When the protective plate 22 is disposed on the upper surface side, the protective plate 22 comes into contact with the support member 20 and is positioned substantially parallel to the grid 6 to protect the grid 6. Therefore, when the photoreceptor unit is taken out, the entire surface of the grid 9 is exposed to the protective plate 22.
This eliminates problems caused by contact with external components or by the hands of service personnel. On the other hand, as shown in FIG. 2b, a housing 30 is provided on the printer main body side, and the housing 30 of the eraser device is attached to the housing 30.
1. Attach the shield case 32 of the charger body 5 and the terminal support member 33 for the bias power supply 8.
A connecting terminal 35 is attached to the tip of the terminal support member 33 via a spring 34. On the other hand, when installing the photoconductor unit into the main body of the apparatus, the photoconductor unit is inserted vertically from above to below, but as shown in FIG. comes into contact with the lower part 31a of the housing 31 of the eraser device 3, and as it is inserted further downward, the protective plate 2
2 rotates around a pivot pin 21, and after installation is completed, it is housed in the housing of the eraser device 3, as shown in FIG. 2b. Therefore, the housing 31 of the eraser device exhibits the function of locking the protective plate. Further, when mounted, one end of the grid 6 comes into contact with a connection terminal 35 connected to the bias power supply 8, and a bias voltage is applied to the grid 6 through this connection terminal 35. As a result, when the printer device is operated, the protective plate 22 is not present on the side of the grid 6 facing the shield case 32 and the bias voltage is appropriately applied, so that the photoreceptor belt 1 is charged to a predetermined surface potential. be able to. Furthermore,
Since the protection plate 22 acts as a shielding plate for the scorotron charger from the eraser light, the charging potential of the photoreceptor belt can be more strictly regulated.

The present invention is not limited to the embodiments described above, but can be modified in various ways. For example, in the above-described embodiments, a printer device was used as an example, but the present invention can also be applied to various electrophotographic devices that use a separate Scorotron charger.

Furthermore, although a belt-shaped photoreceptor was used as the image forming member in the above-described embodiments, it is of course possible to use a photoreceptor drum having a photoreceptor layer formed on the surface of an Al-based substrate.

Furthermore, although a reference voltage source is used as the grid bias source, it may also be constructed with a series branch of a constant voltage drop element and a field effect transistor acting as an electronic volume element.

Further, although the above-described embodiment has a structure in which the photoreceptor unit is inserted and removed in the vertical direction, the present invention can also be applied to an apparatus in which the photoreceptor unit is moved in the horizontal direction to be installed and removed.

Furthermore, although the housing of the eraser device is used as the locking member for the protection plate, a configuration in which the locking member is provided separately may also be used.

(Effects of the invention) As explained above, according to the invention, the protection plate is rotatably mounted opposite the grid fixed to the photoreceptor unit, and the device body is provided with a locking pin that engages with the protection plate. Because it is fixed, when the photoreceptor unit is taken out, the protective plate acts as a shutter against the grid, covering the entire surface of the grid and protecting it.
When the photoreceptor unit is attached to the main body of the apparatus, the protective plate is positioned perpendicular to the grid, allowing the photoreceptor to be charged to a desired potential and effectively preventing the eraser light from going around. As a result, even if the scorotron charger has a separate structure, the charging potential of the photoreceptor can be strictly regulated, and the grid can be effectively protected when the photoreceptor unit is taken out.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an example of an electrophotographic apparatus according to the present invention, FIG.
2 is a diagrammatic cross-sectional view showing a state in which the photoreceptor unit is mounted on the apparatus main body, and FIG. 1... Photoreceptor belt, 3... Eraser device, 4
... Scorotron charger, 5 ... Charger body, 6
... Grid, 7 ... High voltage power supply, 8 ... Bias power supply, 20 ... Support member, 21 ... Pivot pin, 2
2... Protective plate, 31... Eraser device housing, 32... Shield case, 33... Terminal support member, 34... Spring, 35... Connection terminal.

Claims (1)

[Scope of utility model registration request] A scorotron charger having a charger body including a shield case and a corona wire, and a grid to which a predetermined bias voltage is applied, the grid being fixed to a photoreceptor unit including a photoreceptor,
In an electrophotographic apparatus, the charger main body is fixed to the electrophotographic apparatus main body so as to be adjacent to the eraser device, and the photoreceptor unit is detachably attached to the electrophotographic apparatus main body along the vertical direction. A protective plate large enough to cover almost the entire surface of the grid is rotatably mounted on the opposite side of the grid from the photoconductor, and when the photoconductor unit is mounted on the main body of the electrophotographic apparatus, the protection plate is attached to the eraser device. An electrophotographic apparatus, wherein the electrophotographic apparatus is housed in a housing and is configured such that the protection plate faces the grid when the photoreceptor unit is taken out.