JPS63113575A - Peeling device - Google Patents

Abstract

PURPOSE:To execute peeling-off in a state that a satisfactory image is held, by constituting the titled device so that a discharge area obtained by a second charge wire positioned at a distance against the advance direction of a transfer material becomes wider than a discharge area obtained by a first charge wire positioned at this side. CONSTITUTION:The discharge (area the range of an angular aperture theta2) obtained by the second charge wire 27 is set so as to become wider than the discharge area (the range of an angular aperture theta1) obtained by the first charge wire 26. A peeling device 7 separates its function so that in two pieces of charge wires 26, 27 extended and provided in a shielding case 25, the first charge wire 26 of this side against the advance direction of a form P, and the second charge wire 27 being at a distance are used for peeling the form P, and for destaticizing the form P, respectively, and also, the destaticization can be executed gradually since the discharge area of the second charge wire is wider. In such a way, peeling-off in a state that a satisfactory image is held can be executed even by a simple constitution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an improvement in a transfer device applied to an image forming apparatus such as an electronic copying machine or a laser printer.

(Prior Art) Normally, in an image forming apparatus of a type in which a phenomenon agent image is once formed on an image carrier such as a photoreceptor and then transferred to a transfer material such as paper, A peeling device is disposed near the image transfer position, and is configured to peel off the transfer material electrostatically attracted to the image carrier to which the developer image is transferred.

The reason why the transfer material adheres to the image carrier after transfer is as follows.
The charge applied to the back side of the transfer material causes a charge of the opposite polarity to be induced on the image carrier side, and due to the electrostatic force between the induced charge and the charge applied to the transfer material, the transfer material is transferred to the surface of the image carrier. It sticks to the surface and becomes difficult to separate.

In addition, conventional peeling devices have a structure in which a single charge wire (corona discharge electrode) is stretched inside a shield case, and the corona discharge from this charge wire removes the electric charge on the back side of the transfer material that is in close contact with it. Neutralize the transfer material and the induced charge to weaken the electrostatic force, and peel the transfer material from the image carrier so that the stiffness of the transfer material and the transfer material's own weight overcome the electrostatic force. It is structured like this.

(Problems to be Solved by the Invention) However, although the transfer material adsorbed to the surface of the image carrier is peeled off from the image carrier according to the above principle, the distance between the transfer material and the image carrier increases. At this time, if a suitable amount of charge does not leak from the transfer material, the potential between them will suddenly rise and cause a discharge, or when the transfer material comes into contact with the conveying means after separation, the charge will drop. There were problems such as discharge occurring, which disturbed the toner on the transfer material and caused image defects.

In order to prevent this problem from occurring, it is possible to increase the amount of corona discharge from the charge wire (corona discharge electrode) to increase the peeling output, but on the other hand, the charge on the transfer material may be too neutralized. , problems arise in that good transfer cannot be performed.

Therefore, in order to alleviate the above-mentioned problems, conventionally, in order to make each discharge area (frontage angle) approximately equal, a charge wire located in front of the transfer material in the direction of movement of the transfer material is placed 1 meter away from the shield case. Some have two charge wires strung together. However, this peeling device is effective for large-diameter image carriers (photosensitive drums) where the distance between the two charge wires does not vary much;
When installed opposite to an image carrier whose diameter has recently become smaller, the position of the charge wire, which is located far away in the direction of movement of the transfer material, will be far away from the surface position of the image carrier. The output must be increased more than necessary, leading to a complicated configuration. Furthermore, since the transfer material is aligned with the charge wire located in front of the transfer material in the direction of movement, the discharge area is not as wide as expected and there is a problem in that a good peeling process cannot be performed.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a peeling device that has a simple configuration and is capable of peeling while maintaining a good image. It is.

[Structure of the Invention (Means for Solving the Problems)] In order to solve the above-mentioned problems, the present invention provides a shield that is arranged near the image transfer position of the image carrier and has an opening facing the image carrier. A case and a first shield stretched inside the shield case. a second charge wire, and peels off the transfer material sent to the image transfer position and in close contact with the image carrier from the image carrier by corona discharge,
The discharge area obtained by the second charge wire located far away with respect to the traveling direction of the transfer material is made wider than the discharge area obtained by the first charge wire located nearer to you.

(Function) That is, since the present invention has the above configuration, of the two charge wires stretched in the shield case, the first charge wire located on the front side with respect to the direction of movement of the transfer material is The functions of the second charge wire for peeling off the transfer material and for removing snow from the transfer material are separated, and since the discharge area of the second charge wire is widened, static electricity can be gradually removed. There is no need to rapidly neutralize the transfer material as in the past, and the toner on the transfer material does not return to the image carrier side, and maintains a good image without causing problems when it comes into contact with the conveyance means. Peeling is possible in a state where the

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the configuration of the main parts of a two-color copying machine to which an embodiment of the peeling device of the present invention is applied.

In the figure, reference numeral 1 indicates a small drum-shaped photoreceptor with a diameter of about 78 mm as an image carrier, which is placed approximately in the center of the main body of the copying machine. The charging device 2.degree., the light irradiation section 3a of the exposure device 3, the first developing device 4. Second developing device5. Corona discharge device 6 as a transfer device, corona discharge device 7 as a peeling device. Cleaning device 8. and a static eliminator 9 are provided.

In addition, a first and second paper feeding device 10.11 is arranged at the lower right side of the main body of the copying apparatus, and a paper P serving as a transfer material is disposed.
can be selectively supplied.

Further, the paper P selectively fed from these paper feeding devices 10.11 is guided to the registration roller pair 14 via the paper feeding path 12.13, then stopped, and then the registration roller pair 14 is guided through the paper feeding path 12.13. 14, the image is sent to an image transfer section 15 formed between the photoreceptor 1 and the corona discharge device 6 as a transfer position in synchronization with the image forming operation on the photoreceptor 1. .

Further, the paper P fed to the image transfer position 15 and having the image transferred thereto is discharged via a paper conveyance path 16 to a tray (not shown) disposed on the left side of the main body of the copying apparatus. The fixing device 17 performs fixing during the transportation.

Note that 18 and 19 are paper guides that guide the paper P fed by the registration rollers 14 with mutually opposing surfaces to guide it to the image transfer position 15, 20 is a suction conveyance belt constituting the conveyance means after peeling, and 21 is a paper guide. It is a mechanical peeling device.

The copying process of the copying apparatus configured as described above is performed as follows.

That is, after the photoreceptor 1 is uniformly charged by charging by the charging station 2, an electrostatic latent image of a document image (not shown) is formed by an exposure operation by the exposure device 3.

This electrostatic latent image is developed into a predetermined color and visualized by the first developing device 4 or the second developing device 5, which selectively operates.

On the other hand, in synchronization with the image forming operation on the photoreceptor 1, the image transfer section 15
A sheet P is fed into the sheet P, and the developer image on the photoreceptor 1 is transferred onto the sheet P by the DC corona discharge action of the corona discharge device 6 as a transfer device.

Next, the sheet P electrostatically attracted to the photoreceptor 1 is peeled off by the alternating current corona discharge action of the corona discharge device 7 as a peeling device, and after being sent to the fixing device 17 via the paper conveyance path 16, the paper P is transferred to the fixing device 17 (not shown). It will be ejected to the tray.

On the other hand, the surface of the photoreceptor 1 after the transfer is brought into a clean state by facing the cleaning device 8 and the static eliminator 9 in sequence, and enters the next copying cycle.

Next, the configuration of the corona discharge device 7 as the peeling device of the present invention will be explained.

This corona discharge device 7 includes a shield case 25 with an opening 25a facing the photoreceptor 1, as shown in FIG.
The first wire, which is made of tungsten wire and has a diameter of about 80 mm, is stretched inside the shield case 25. It has a structure comprising second charge wires (corona discharge electrodes) 26 and 27.

The shield case 25 is integrally constructed with the shield case 28 of the corona discharge device @6 constituting the transfer device, and is separated by a partition plate 29. In addition, 30 in the figure
31 is a guide for guiding the peeled paper P, and 31 is a charge wire of a corona discharge device @6 as a transfer device.

Further, the second charge wire 27 located at the rear with respect to the traveling direction of the paper P is stretched upwardly displaced from the first charge wire 26 located at the front. The distances between the wires 26 and 27 from the photoreceptor 1 are approximately the same.

Then, the discharge region obtained by the second charge wire 27 (range indicated by the aperture angle 02) is set wider than the discharge region obtained by the first charge wire 26 located on the near side (range indicated by the aperture angle e1). There are 5 people.

In addition, the voltage applied to the second charge wire 27 is
The voltage applied to the charge wire 26 is set to be weaker than that applied to the charge wire 26.

Therefore, in the stripping device 7 configured as described above, of the two charge wires 26 and 27 stretched in the shield case 25, the charge wire 26, 27, which is located on the front side with respect to the traveling direction of the paper P, is used. The first charge wire 26 is used for peeling off the paper P, and the second charge wire 27 located far away is used for eliminating static electricity from the paper P, and the discharge area of the second charge wire 27 is widened. Static charge can be removed gradually, there is no need to remove static electricity from the MP suddenly as in the past, and there is no problem such as the toner on the paper P being returned to the photoreceptor 1 side. It is possible to peel off while maintaining a good image without causing any trouble when it comes into contact with the belt 20.

Although the above-mentioned embodiment is applied to a two-color copying device, the present invention is not limited to this, and is applicable to a case in which it is necessary to peel off paper that is electrostatically attracted to a photoreceptor as an image carrier. Of course, it can be applied to anything.

"Effects of the Invention" As explained above, the present invention comprises a shield case disposed near the image transfer position of the image carrier and with its opening facing the image carrier, and a first shield case stretched inside the shield case. ．． Second
In a peeling device that peels off the transfer material sent to the image transfer position and in close contact with the image carrier from the image carrier by corona discharge, the charge wire is provided with a The discharge area obtained by the second charge wire located on the front side is made wider than the discharge area obtained by the first charge wire located on the front side. Therefore, of the two charge wires stretched inside the shield case, the first charge wire located on the front side with respect to the traveling direction of the transfer material is used for peeling off the transfer material, and the first charge wire located further away is used for peeling off the transfer material. In addition to separating the functions of the second charge wire for defrosting the transfer material, the discharge area of the second charge wire has been widened so that static electricity can be gradually removed, and a good image can be maintained despite the simple configuration. This has the advantage that it is possible to provide a peeling device that can perform peeling in a state where the peeling is performed.

[Brief explanation of the drawing]

FIG. 1 is a configuration explanatory diagram showing one embodiment of the present invention, and FIG. 2 is a schematic longitudinal sectional front view showing the configuration of the main parts of a copying apparatus employing the present invention. 1... Image carrier (photoreceptor), 7... Peeling device, 15
...Image transfer position, 25...Shield case, 25a
... opening, 26 ... first charge wire, 27.
...Second charger wire, P...Transfer material (paper). Applicant's agent Patent attorney Takehiko Suzue Figure 1

Claims (2)

[Claims] (1) A shield case is provided near the image transfer position of the image carrier and has an opening facing the image carrier, and first and second charge wires are stretched within the shield case. In the peeling device that peels off the transfer material sent to the image transfer position and in close contact with the image carrier from the image carrier by corona discharge, a second charge wire located far away with respect to the traveling direction of the transfer material A peeling device characterized in that the discharge area obtained is wider than the discharge area obtained by the first charge wire located on the front side. (2) The peeling device according to claim 1, wherein the voltage applied to the second charge wire is lower than the voltage applied to the first charge wire.