JPH0850391A - Charging device - Google Patents

Abstract

PURPOSE:To stably charge a body with a simple constitution and by aerial discharge applying relatively low-voltage. CONSTITUTION:The charging device is provided with the flexible electrically insulated structure 1 arranged so as to uniformly come in elastic contact with the surface of the photoreceptor 11, the conductive layer 2 uniformly disposed on the contact face side with the photoreceptor 11 of the electrically insulated structure 1, and the conductive pattern 4 disposed in a reticulate state or in a parallel fine line state on the surface of the conductive layer 2 across the electrically insulated thin layer 3. Then, the surface of the photoreceptor 11 is charged by the aerial discharge between the conductive layer 2 and the conductive pattern 4 by applying DC or DC and AC superimposed voltage in between the conductive layer 2 and the conductive pattern 4 from the AC power source 6 and the DC power source 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device, and more particularly to a charging device suitable for use in an image forming apparatus (laser beam printer, copying machine, plain paper facsimile, etc.) which utilizes an electrophotographic process using a photoconductor. .

[0002]

2. Description of the Prior Art The mainstream of charging devices to date has been corona charging devices such as corotrons and scorotrons, but since corona charging devices require a high voltage of 10,000 V or higher, generation of ozone can be avoided. There was a problem that it was not there.

Therefore, in recent years, contact charging devices have begun to spread. A roller-type contact charging device, which is a representative of the contact charging devices currently put into practical use, charges a charged member by an air discharge generated in a gap between the charged member and a roller.

[0004]

The conventional roller-type contact charging device described above charges an object to be charged by the air discharge generated in the gap between the object to be charged and the roller. The charge value is likely to be non-uniform due to the non-uniformity of the gap between the body and the roller, a high applied voltage of 1,000 V or more is required, and a relatively large pressing pressure is applied to keep the discharge gap constant. There were problems such as the need.

In view of the above points, an object of the present invention is to provide a charging device having a simple structure and capable of stably charging an object to be charged by an air discharge at a relatively low voltage. Especially.

[0006]

The charging device of the present invention is a charging device for charging the surface of an object to be charged by air discharge, and is arranged so as to uniformly elastically contact the surface of the object to be charged. A flexible electrically insulating structure, a conductive layer uniformly provided on the contact surface side of the electrically insulating structure with the charged body, and an electrically insulating layer on the surface of the conductive layer. A conductive pattern provided in a mesh shape or parallel thin lines via a thin layer, and by applying a direct current or a superimposed voltage of direct current and alternating current between the conductive layer and the conductive pattern. It is characterized in that the surface of the charged body is charged by air discharge.

[0007]

In the charging device of the present invention, when a charging voltage is applied between the conductive layer and the conductive pattern, the air discharge is performed at the electrode interval corresponding to the thickness of the electrically insulating thin layer, and the charged object is charged. The body is uniformly charged.

[0008]

The present invention will be described in detail with reference to the drawings.

1 and 2 are an enlarged sectional view and an enlarged bottom view of an essential portion showing a charging device 10 according to an embodiment of the present invention. The charging device 10 according to the present exemplary embodiment is arranged so as to make uniform elastic contact with the surface (outer peripheral surface) of the photoconductor 11 along the longitudinal direction (so as to be substantially orthogonal to the moving direction of the surface of the photoconductor 11). Flexible blade-shaped electrically insulating structure 1, a conductive layer 2 uniformly provided on the contact surface side of the electrically insulating structure 1 with the photoconductor 11, and a conductive layer 2 And a wear-resistant insulating layer 5 provided on the surface of the conductive pattern 4 and a conductive pattern 4 provided in parallel thin lines on the outer surface of the conductive pattern 4 with an electrically insulating thin layer 3 interposed therebetween. 2 is connected to an AC power supply 6 and a DC power supply 7 to which a DC voltage or a superimposed voltage (or current) of DC and AC is applied, and the conductive pattern 4 is grounded.

The electrically insulating structure 1 is a plastic film made of engineering plastic such as polypropylene, polyethylene terephthalate, polyethylene or the like, and is formed in a thin blade shape having a length of about 5 to 20 mm and a thickness of about 50 μm.

The conductive layer 2 is formed by vapor deposition of a metal such as aluminum or copper to a thickness of about 1 μm.

The thin electrically insulating layer 3 has a thickness of about 10 μm by printing an insulating material made of a fluorocarbon resin such as Teflon or polyphenyl ether in parallel thin lines with a slit width of about 5 μm and a slit interval of about 20 μm. Has been formed. The thickness of the electrically insulating thin layer 3 is allowed up to about 200 μm based on Paschen's law.

The conductive pattern 4 is an electrically insulating thin layer 3
A metal having a thickness of about 1 μm is formed by vapor-depositing a metal such as aluminum or copper in the shape of parallel thin lines having the same shape as the electrically insulating thin layer 3 on the top.

The wear-resistant insulating layer 5 is made of a fluororesin such as Teflon or polyphenyl ether, and is formed on the conductive pattern 4 in substantially the same shape as the conductive pattern 4, but at the upper and lower sides (in FIG. 2). (2) is removed to form a parallel thin line to have a thickness of about 2 μm. As a result, the upper and lower sides of the conductive pattern 4 exposed to the outside are used as a common ground wire.

The DC power supply 7 generates a voltage of about 600 V in absolute value, and the AC power supply 6 gives a similar AC fluctuation to the voltage of the DC power supply 7. When a charging voltage is applied between the conductive layer 2 and the conductive pattern 4, the electrode interval (corresponding to the thickness of the electrically insulating thin layer 3) at this time is about 10 μm, so that at room temperature and normal pressure. It is possible to reliably start the air discharge at about 400V. Therefore, when the surface of the photoconductor 11 is charged to about 600 V, the applied voltage is about 600 V, which is a low value of about 1/2 of that of the conventional roller-type contact charging device.

FIG. 3 is a side view showing an example of an image forming apparatus provided with the charging device 10 of this embodiment. In this image forming apparatus, the optical scanning system 1 is provided around the photoconductor 11 and on the downstream side of the charging device 10 of the present embodiment when viewed in the rotation direction of the photoconductor 11.
2, a developing device 13, a transfer roller 14, and a cleaner blade 15 are sequentially arranged. In addition, in FIG.
Reference numeral 16 is a fixing device, S is a recording medium such as paper, and T is a developer.

Next, the operation of the charging device 10 of the present embodiment thus constructed will be described together with the operation of the image forming apparatus shown in FIG.

When the photoconductor 11 is rotated in the direction shown by the arrow by a drive source (not shown), the surface of the photoconductor 11 in contact with the lower surface of the charging device 10 has a charging voltage from the AC power source 6 and the DC power source 7. (Or current) depending on the conductive layer 2
Are uniformly charged by the air discharge generated between the conductive pattern 4 and the conductive pattern 4.

Next, the uniformly charged surface of the photoreceptor 11 is exposed with image information by the optical scanning system 12 to form an electrostatic latent image.

Subsequently, the photoconductor 11 on which the electrostatic latent image is formed
When the surface of the developing device reaches a position facing the developing device 13, the developing device 1
The electrostatic latent image is visualized by the developer T supplied from the developer 3 to form a developer image.

Next, the developer image formed on the photoconductor 11 is transferred to the surface of the recording medium S by passing through the contact portion with the transfer roller 14.

The developer T remaining on the photoconductor 11 without being transferred to the recording medium S is scraped off by the cleaner blade 15 and cleaned.

The cleaned surface of the photoreceptor 11 is
It again reaches the contact position with the charging device 10 and is uniformly charged again by the charging device 10.

By repeating the above steps, an image of the developer T is formed on the recording medium S, the developer T is fixed by the fixing device 16, and the recording medium S is discharged to the outside of the image forming apparatus.

In the image forming apparatus shown in FIG. 3, the cleaner blade 15 is provided.
It is also possible to make 0 serve as a cleaner function as well as a charging function. Further, the charging device 10 is not limited to one, and a plurality of charging devices can be arranged.

FIG. 4 is an enlarged bottom view of a main part of a charging device 10A according to another embodiment of the present invention. In the charging device 10 of the embodiment shown in FIGS. 1 and 2, the conductive pattern 4 is formed in parallel thin lines, whereas in the charging device 10A of this embodiment, the conductive pattern 4 is 10 μm × 10 μm square. A large number of through holes are formed at intervals of about 10 μm in a mesh shape.

Even if the conductive pattern 4 is formed in a net shape in this manner, it is between the conductive layer 2 and the conductive pattern 4 as in the case of the parallel thin line conductive pattern 4 shown in FIG. When a charging voltage of about 600V is applied, the surface of the photoconductor 11 can be uniformly charged to about 600V by the air discharge between the conductive layer 2 and the conductive pattern 4.

FIG. 5 is a side view showing an image forming apparatus in which a charging device 10B according to another embodiment of the present invention, in which the electrically insulating structure 1 is formed in the shape of a flexible thin film tube, is arranged. The charging device 10B of the present embodiment is similar to FIG. 1 except that the electrically insulating structure 1 is formed in a flexible thin film tube shape having the conductive layer 2 and the conductive pattern 4 on the outer peripheral surface side.
Since it is formed similarly to the charging device 10 (or 10A) shown in FIG. 2 (or FIG. 4), detailed description thereof will be omitted. Also, regarding the image forming apparatus, the portions corresponding to those of the image forming apparatus shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In the charging device 10B of the present embodiment having such a configuration, the charging device 10B is rotatably supported so as to be elastically in contact with the photoconductor 11 and shown in FIGS. It goes without saying that the same operation and effect as those of the charging device 10 (or 10A) shown in FIG. 4) can be obtained.

FIG. 6 is a side view showing an image forming apparatus in which a charging device 10C according to another embodiment of the present invention, in which the electrically insulating structure 1 is formed in a flexible bag shape, is arranged. 1C and FIG. 2C except that the electrically insulating structure 1 is formed in a flexible bag shape having the conductive layer 2 and the conductive pattern 4 on the outer surface side. Alternatively, since it is formed similarly to the charging device 10 (or 10A) shown in FIG. 4), detailed description thereof will be omitted. Also, regarding the image forming apparatus, the portions corresponding to those of the image forming apparatus shown in FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

It can be said that the charging device 10C of this embodiment having the above-described structure can also obtain the same operation and effect as the charging device 10 (or 10A) shown in FIGS. 1 and 2 (or FIG. 4). There is no end.

In the above embodiment, the member to be charged is the photosensitive member 11. However, the member to be charged is not limited to the photosensitive member 11 and may be any electrically defective conductor.

[0033]

As described above, according to the present invention,
The electrically conductive layer is uniformly provided on the contact surface side of the electrically insulating structure with the member to be charged, and the electrically conductive layer is provided on the surface of the electrically conductive layer in the form of a net or parallel thin lines with the electrically insulating thin layer interposed therebetween. The charge voltage is applied between the conductive pattern and the conductive pattern to give the charge to the surface of the charged body by the air discharge, so that the charged body has an extremely simple structure and a relatively low charging voltage. There is an effect that the surface of the can be uniformly charged.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of an essential part showing the configuration of a charging device according to an exemplary embodiment of the present invention.

FIG. 2 is an enlarged bottom view of the main parts showing the configuration of the charging device of the present embodiment.

FIG. 3 is a side view showing an example of an image forming apparatus provided with the charging device of the present exemplary embodiment.

FIG. 4 is an enlarged bottom view of essential parts showing the configuration of a charging device according to another embodiment of the present invention.

FIG. 5 is a side view showing an image forming apparatus in which a charging device according to another embodiment of the present invention, in which an electrically insulating structure is formed into a flexible thin film tube, is arranged.

FIG. 6 is a side view showing an image forming apparatus in which a charging device according to still another embodiment of the present invention, in which an electrically insulating structure is formed in a flexible bag shape, is arranged.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrically insulating structure 2 Conductive layer 3 Electrically insulating thin layer 4 Conductive pattern 5 Abrasion resistant insulating layer 6 AC power supply 7 DC power supply 10, 10A, 10B, 10C Charging device 11 Photoconductor 12 Optical scanning system 13 developing device 14 transfer roller 15 cleaner blade 16 fixing device S recording medium T developer

Claims (4)

[Claims] 1. A charging device for charging the surface of a body to be charged by air discharge, comprising: a flexible electrically insulating structure arranged so as to uniformly elastically contact the surface of the body to be charged. A conductive layer uniformly provided on the contact surface side of the electrically insulating structure with the member to be charged, and a net-like or parallel thin line on the surface of the electrically conductive layer with an electrically insulating thin layer interposed therebetween. And a conductive pattern provided in a shape, by applying a direct current or a superimposed voltage of direct current and alternating current between the conductive layer and the conductive pattern by the air discharge on the surface of the body to be charged. A charging device characterized by being charged. 2. A gap 20 corresponding to the thickness of the electrically insulating thin layer is provided between the conductive layer and the conductive pattern.
The charging device according to claim 1, wherein an air layer having a thickness of 0 μm or less is present. 3. The charging device according to claim 1, wherein the electrically insulating structure has a flexible blade shape, a flexible thin film tube shape, or a flexible bag shape. 4. The charging device according to claim 1, wherein a wear-resistant insulating layer is provided on the surface of the conductive pattern.